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RSS2014 Vol. 26, No. 07
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2014,
26: 070101.
doi: 10.11884/HPLPB201426.070101
Abstract:
To verify nuclear components dismantled from a nuclear warhead or stored in a nuclear facility, a neutron multiplicity counter with 32 3He tubes and high density polythene cavity was built. Eight channel circuits were used to process the signals from 3He tubes. Five 252Cf neutron sources were used to calibrate parameters of the counter. To improve the mass assay accuracy, analysis algorithm for weighted point model and double Am-Li neutron sources neutron multiplicity counting were studied. The neutron multiplicity distribution for six weapon-grade plutonium components and seven highly enriched uranium components were measured with the neutron multiplicity counter, assay results show that the mass assay bias is below 1.3% for plutonium components with the weighted neutron multiplicity model, while the value is below 5% for uranium components with calibration curve method.
To verify nuclear components dismantled from a nuclear warhead or stored in a nuclear facility, a neutron multiplicity counter with 32 3He tubes and high density polythene cavity was built. Eight channel circuits were used to process the signals from 3He tubes. Five 252Cf neutron sources were used to calibrate parameters of the counter. To improve the mass assay accuracy, analysis algorithm for weighted point model and double Am-Li neutron sources neutron multiplicity counting were studied. The neutron multiplicity distribution for six weapon-grade plutonium components and seven highly enriched uranium components were measured with the neutron multiplicity counter, assay results show that the mass assay bias is below 1.3% for plutonium components with the weighted neutron multiplicity model, while the value is below 5% for uranium components with calibration curve method.
2014,
26: 071001.
doi: 10.11884/HPLPB201426.071001
Abstract:
Spray cooling experiments were performed on the heater with different micro-structured surfaces. A smooth surface was also tested for comparison. The micro-structures consisted of uniform porous tunnels with different size, and tests were conducted in an open system with ammonia as the working fluid. When the heat flux was 300 W/cm2, the surfaces temperature was kept below 28 ℃. This result indicated that ammonia was a optional fluid for diode laser cooling application. Moreover, the uniform micro-structured surfaces offered significant performance enhancement of heat transfer. At 511.5 W/cm2, heat transfer coefficient reached to 346 701.1 W/(m2℃) which corresponded to 83.9% increase over smooth surface.
Spray cooling experiments were performed on the heater with different micro-structured surfaces. A smooth surface was also tested for comparison. The micro-structures consisted of uniform porous tunnels with different size, and tests were conducted in an open system with ammonia as the working fluid. When the heat flux was 300 W/cm2, the surfaces temperature was kept below 28 ℃. This result indicated that ammonia was a optional fluid for diode laser cooling application. Moreover, the uniform micro-structured surfaces offered significant performance enhancement of heat transfer. At 511.5 W/cm2, heat transfer coefficient reached to 346 701.1 W/(m2℃) which corresponded to 83.9% increase over smooth surface.
2014,
26: 071002.
doi: 10.11884/HPLPB201426.071002
Abstract:
In order to get a better filtering result for the output of data of fiber optic gyroscope (FOG), an adaptive LMS Algorithm with Variable Step and Multi-scale Wavelet Transform(MVSLMS) was applied to FOG data processing. A MVSLMS filter was constructed on the basis of the characteristics of FOG data, and the specific implementation steps were proposed. The measured static data, vibration test data and rate test data of FOG were filtered. The experimental results show that the proposed algorithm significantly inhibits the random noise of FOG. Compared with the conventional LMS algorithm, after filtered with new algorithm, the zero drift stability of FOG output data is decreased by 72% under static condition, 91.5%, 77.4% and 96.5% before vibration, in vibration and after vibration. The standard deviation of FOG output data is decreased by 54.4% under rate test condition. The filter results under rocking motion condition confirmed that the proposed algorithm has better signal tracking capability.
In order to get a better filtering result for the output of data of fiber optic gyroscope (FOG), an adaptive LMS Algorithm with Variable Step and Multi-scale Wavelet Transform(MVSLMS) was applied to FOG data processing. A MVSLMS filter was constructed on the basis of the characteristics of FOG data, and the specific implementation steps were proposed. The measured static data, vibration test data and rate test data of FOG were filtered. The experimental results show that the proposed algorithm significantly inhibits the random noise of FOG. Compared with the conventional LMS algorithm, after filtered with new algorithm, the zero drift stability of FOG output data is decreased by 72% under static condition, 91.5%, 77.4% and 96.5% before vibration, in vibration and after vibration. The standard deviation of FOG output data is decreased by 54.4% under rate test condition. The filter results under rocking motion condition confirmed that the proposed algorithm has better signal tracking capability.
2014,
26: 071003.
doi: 10.11884/HPLPB201426.071003
Abstract:
The characteristics of two modeling methods are discussed. Correlative theory of model modification method is introduced. The sensitivity factors of Youngs modulus, density, inner diameter and thickness of frame, motherboard and stiffened plate are obtained by sensitivity analysis. By comparing the theoretical results with the experimental data, the dynamical modification problem is established, and the dynamical model which contains nonlinear joints is updated. The results show that the average error is 2.5%, which satisfies the engineering requirements. At last, the orders are modified too.
The characteristics of two modeling methods are discussed. Correlative theory of model modification method is introduced. The sensitivity factors of Youngs modulus, density, inner diameter and thickness of frame, motherboard and stiffened plate are obtained by sensitivity analysis. By comparing the theoretical results with the experimental data, the dynamical modification problem is established, and the dynamical model which contains nonlinear joints is updated. The results show that the average error is 2.5%, which satisfies the engineering requirements. At last, the orders are modified too.
2014,
26: 071004.
doi: 10.11884/HPLPB201426.071004
Abstract:
The single oxide films damage at different laser energy values was studied with the photo-acoustic method. The acoustic acquisition was established. The frequency spectrum curves was obtained by the Fourier transform of in-time signals. In the experiment, we compared and analysed the frequency spectrum curves from 24 kHz to 40 kHz between the damaged film and undamaged one. By extracting frequency features and establishing frequency curve similarity function, it was possible to judge whether the optical film was damaged. The experimental result shows that the acoustic frequency method can be easily efficient to judge accurately film damage and it can be also used in online inspection conveniently.
The single oxide films damage at different laser energy values was studied with the photo-acoustic method. The acoustic acquisition was established. The frequency spectrum curves was obtained by the Fourier transform of in-time signals. In the experiment, we compared and analysed the frequency spectrum curves from 24 kHz to 40 kHz between the damaged film and undamaged one. By extracting frequency features and establishing frequency curve similarity function, it was possible to judge whether the optical film was damaged. The experimental result shows that the acoustic frequency method can be easily efficient to judge accurately film damage and it can be also used in online inspection conveniently.
2014,
26: 071005.
doi: 10.11884/HPLPB201426.071005
Abstract:
For the problem that objects in image center is excursing while camera is zooming, this paper analyses the modeling and improves the traditional method. Based on the results, a calibration method of camera axis offset based on image analysis is put forward. Moreover, some optimizations are processed in the validation experiment by rectangular object imaging with different focal length, whose results show that the method could accurately calibrate the camera axis offset. After calibration of camera, axis deviation jitter is lower than 0.6% of view angle, which could provide facility for using camera under high precision situations.
For the problem that objects in image center is excursing while camera is zooming, this paper analyses the modeling and improves the traditional method. Based on the results, a calibration method of camera axis offset based on image analysis is put forward. Moreover, some optimizations are processed in the validation experiment by rectangular object imaging with different focal length, whose results show that the method could accurately calibrate the camera axis offset. After calibration of camera, axis deviation jitter is lower than 0.6% of view angle, which could provide facility for using camera under high precision situations.
2014,
26: 071006.
doi: 10.11884/HPLPB201426.071006
Abstract:
The hardness and thermal properties of the nonlinear optical crystal YCOB were systematically measured. The results show that the hardness along the (100), (010) and (001) directions has low anisotropy, which is beneficial for the cutting process. The specific heat of YCOB crystal is 0.74 Jg-1K-1 at 330 K, and the thermal conductivities along the principal axes are 1.74, 2.16 and 3.08 Wm-1K-1, indicating a moderate thermal conductivity.
The hardness and thermal properties of the nonlinear optical crystal YCOB were systematically measured. The results show that the hardness along the (100), (010) and (001) directions has low anisotropy, which is beneficial for the cutting process. The specific heat of YCOB crystal is 0.74 Jg-1K-1 at 330 K, and the thermal conductivities along the principal axes are 1.74, 2.16 and 3.08 Wm-1K-1, indicating a moderate thermal conductivity.
2014,
26: 071007.
doi: 10.11884/HPLPB201426.071007
Abstract:
Dense Nd:YAG transparent ceramic was obtained by slip casting and vacuum sintering. The effect of sintered temperature and dwell time on the densification and microstructure development of Nd:YAG transparent ceramics were investigated. The YAP and YAM formation appeared from 1050 ℃ up to 1300 ℃, resulting in a significant densification. YAG was obtained in the vicinity of 1400 ℃, whereas beyond 1400 ℃, no other phase was detected. The densification and grain size increased with the increasing of the sintered temperature. Pore free Nd:YAG transparent ceramic with a grain size of 5 m to 10 m was obtained between 1700 ℃ and 1800 ℃ sintering for 20 h.
Dense Nd:YAG transparent ceramic was obtained by slip casting and vacuum sintering. The effect of sintered temperature and dwell time on the densification and microstructure development of Nd:YAG transparent ceramics were investigated. The YAP and YAM formation appeared from 1050 ℃ up to 1300 ℃, resulting in a significant densification. YAG was obtained in the vicinity of 1400 ℃, whereas beyond 1400 ℃, no other phase was detected. The densification and grain size increased with the increasing of the sintered temperature. Pore free Nd:YAG transparent ceramic with a grain size of 5 m to 10 m was obtained between 1700 ℃ and 1800 ℃ sintering for 20 h.
2014,
26: 071008.
doi: 10.11884/HPLPB201426.071008
Abstract:
Similar with the mode instability in high-power fiber lasers induced by multimode interference and optical-thermal coupling, the output power and the beam quality of large-scale resonator based solid state lasers turn out to be irregularly temporal jitter along with high output power. This phenomenon is mainly due to medium intensity inhomogeneous which results from asymmetric laser oscillation within the unstable resonator and coupling between laser extraction and medium heat generation. For three different laser types, Nd: YAG thin-disk laser, Yb: YAG thin-disk laser and immersed liquid-cooled disk laser, theoretical analysis and numerical simulation are conducted in order to provide basic rules of laser output and distinct optical-thermal coupling mechanism. The results show that dynamics instability only appears within a certain interval since the dynamics presents saturation effects for the former two kinds of lasers. Thus, the instability can be avoided by choosing proper parameters. But for immersed liquid-cooled disk laser, it has obvious threshold under strong optical intensity, dynamics instability can be suppressed only by lower cooling absorption coefficient.
Similar with the mode instability in high-power fiber lasers induced by multimode interference and optical-thermal coupling, the output power and the beam quality of large-scale resonator based solid state lasers turn out to be irregularly temporal jitter along with high output power. This phenomenon is mainly due to medium intensity inhomogeneous which results from asymmetric laser oscillation within the unstable resonator and coupling between laser extraction and medium heat generation. For three different laser types, Nd: YAG thin-disk laser, Yb: YAG thin-disk laser and immersed liquid-cooled disk laser, theoretical analysis and numerical simulation are conducted in order to provide basic rules of laser output and distinct optical-thermal coupling mechanism. The results show that dynamics instability only appears within a certain interval since the dynamics presents saturation effects for the former two kinds of lasers. Thus, the instability can be avoided by choosing proper parameters. But for immersed liquid-cooled disk laser, it has obvious threshold under strong optical intensity, dynamics instability can be suppressed only by lower cooling absorption coefficient.
2014,
26: 071009.
doi: 10.11884/HPLPB201426.071009
Abstract:
The frequency conversion of existed laser sources using infrared nonlinear optical (NLO) crystals is the main way to generate 3-5 m and 8-12 m atmospheric windows infrared sources. The traditional infrared nonlinear optical crystals have shortcomings of one kind or another which seriously limits their applications and cannot meet the application requirements. Therefore, it is practically and scientifically important to study and search for new infrared NLO crystals. In this paper, an overview on the progress of searching for new infrared NLO crystals in chalcogenides was presented. The new development in the growth and characterization of LiMQ2(M=Ga, In;Q=S, Se, Te),BaGa4S7,BaGa4Se7,BaGa2MQ6(M = Si, Ge;Q = S, Se), and Li2In2MQ6 (M = Si, Ge;Q = S, Se) was reported.
The frequency conversion of existed laser sources using infrared nonlinear optical (NLO) crystals is the main way to generate 3-5 m and 8-12 m atmospheric windows infrared sources. The traditional infrared nonlinear optical crystals have shortcomings of one kind or another which seriously limits their applications and cannot meet the application requirements. Therefore, it is practically and scientifically important to study and search for new infrared NLO crystals. In this paper, an overview on the progress of searching for new infrared NLO crystals in chalcogenides was presented. The new development in the growth and characterization of LiMQ2(M=Ga, In;Q=S, Se, Te),BaGa4S7,BaGa4Se7,BaGa2MQ6(M = Si, Ge;Q = S, Se), and Li2In2MQ6 (M = Si, Ge;Q = S, Se) was reported.
2014,
26: 072001.
doi: 10.11884/HPLPB201426.072001
Abstract:
To control the inner diameter change of double emulsions and to improve the surface finish of the resulting poly(-methyl styrene) (PAMS) capsules, the effects of electrolyte in the inner and outer water phases on the water migration and phase separation behaviors in the oil phase layer during curing process were investigated. The results show that addition of electrolyte only in the inner water phase leads to a migration of the water from the inner to the outer water phase and thus results in a shrinking of the double emulsions, potentially wrinkling the resulting PAMS capsules. When adding electrolyte into the inner and outer water phases at the same time, the chemical potential of the inner water phase balances with that of the outer water phase, so that the generation of water microdroplets and the migration of water in the oil phase layer during the curing process are suppressed and then the vacuoles in the shell wall of the resulting PAMS capsules are reduced. Moreover, through adjusting the concentrations of electrolyte in the inner and outer water phases, the densities of the three phases of the double emulsions can also be matched for improving the sphericity and wall thickness uniformity of the resulting PAMS capsules.
To control the inner diameter change of double emulsions and to improve the surface finish of the resulting poly(-methyl styrene) (PAMS) capsules, the effects of electrolyte in the inner and outer water phases on the water migration and phase separation behaviors in the oil phase layer during curing process were investigated. The results show that addition of electrolyte only in the inner water phase leads to a migration of the water from the inner to the outer water phase and thus results in a shrinking of the double emulsions, potentially wrinkling the resulting PAMS capsules. When adding electrolyte into the inner and outer water phases at the same time, the chemical potential of the inner water phase balances with that of the outer water phase, so that the generation of water microdroplets and the migration of water in the oil phase layer during the curing process are suppressed and then the vacuoles in the shell wall of the resulting PAMS capsules are reduced. Moreover, through adjusting the concentrations of electrolyte in the inner and outer water phases, the densities of the three phases of the double emulsions can also be matched for improving the sphericity and wall thickness uniformity of the resulting PAMS capsules.
2014,
26: 072002.
doi: 10.11884/HPLPB201426.072002
Abstract:
According to the spatial distribution data of the refractive index of KDP crystals obtained with orthogonal polarization interferometry (OPI), the internal detuning angle distributions have been calculated. Consequently, the optimization model and method of the best input angle of full aperture for doubler and tripler KDP crystals have been established. The variations of the input angle of doubler and tripler KDP crystals with different initial intensity of fundamental field have been analyzed and discussed. On this basis, the best input angles of the full aperture for measured KDP crystals have been optimized. The results show that doubler is sensitive to non-uniformity of refractive index while tripler is not for the relatively large values of RMS of internal detuning angle. Consequently, the method for determining the best input angle of the full aperture for doubler and tripler KDP crystals can be optimized. In practical applications, we optimize the best input angle of actually measured tripler assuming the refractive index of doubler is uniform at first. After that, the best input angle of actually measured doubler and tripler could be obtained through appropriately adjusting the input angles of doubler and tripler, respectively.
According to the spatial distribution data of the refractive index of KDP crystals obtained with orthogonal polarization interferometry (OPI), the internal detuning angle distributions have been calculated. Consequently, the optimization model and method of the best input angle of full aperture for doubler and tripler KDP crystals have been established. The variations of the input angle of doubler and tripler KDP crystals with different initial intensity of fundamental field have been analyzed and discussed. On this basis, the best input angles of the full aperture for measured KDP crystals have been optimized. The results show that doubler is sensitive to non-uniformity of refractive index while tripler is not for the relatively large values of RMS of internal detuning angle. Consequently, the method for determining the best input angle of the full aperture for doubler and tripler KDP crystals can be optimized. In practical applications, we optimize the best input angle of actually measured tripler assuming the refractive index of doubler is uniform at first. After that, the best input angle of actually measured doubler and tripler could be obtained through appropriately adjusting the input angles of doubler and tripler, respectively.
2014,
26: 072003.
doi: 10.11884/HPLPB201426.072003
Abstract:
The platform which is used to carry diagnostic instruments on Shenguang facility requires high positioning accuracy and working stability，and can aim at the target with reliability. A double optical path automatic adjusting and aiming system is designed, its position accuracy is 20 m. It employs a double optical image system and a 3-DOF motion components. In this system, visual servo technology is used to realize the automatic aiming. Automatic positioning test indicates that pointing accuracy is 11 m in x direction, 12 m in y direction and radical positioning accuracy is 14 m. Laser shot test with X-ray framing camera shows that the automatic aiming system can satisfy the projects requirement.
The platform which is used to carry diagnostic instruments on Shenguang facility requires high positioning accuracy and working stability，and can aim at the target with reliability. A double optical path automatic adjusting and aiming system is designed, its position accuracy is 20 m. It employs a double optical image system and a 3-DOF motion components. In this system, visual servo technology is used to realize the automatic aiming. Automatic positioning test indicates that pointing accuracy is 11 m in x direction, 12 m in y direction and radical positioning accuracy is 14 m. Laser shot test with X-ray framing camera shows that the automatic aiming system can satisfy the projects requirement.
2014,
26: 072004.
doi: 10.11884/HPLPB201426.072004
Abstract:
For Z-pinch physical experiment, aluminum cingulum array loads with self-accommodating structure were designed. The cutting technology for aluminum foil was researched by handiwork and laser. The figure and mechanical performance of aluminum cingulum that was cut from aluminum foil were characterized, and the aluminum cingulums that was cut by laser were suitable for aluminum cingulum array loads. The mechanical performance of aluminum cingulum cut by laser was characterized. For a 30 mm1 mm5 m aluminum cingulum, the tensile strength was about 116 cN and the elongation was about 1.3%. Aluminum cingulum array loads with self-accommodating structure were prepared using the aluminum cingulum cut by laser, and the self-accommodating quantity was up to 4.5 mm which could meet the need of Qiangguang-Ⅰ facility physical experiment.
For Z-pinch physical experiment, aluminum cingulum array loads with self-accommodating structure were designed. The cutting technology for aluminum foil was researched by handiwork and laser. The figure and mechanical performance of aluminum cingulum that was cut from aluminum foil were characterized, and the aluminum cingulums that was cut by laser were suitable for aluminum cingulum array loads. The mechanical performance of aluminum cingulum cut by laser was characterized. For a 30 mm1 mm5 m aluminum cingulum, the tensile strength was about 116 cN and the elongation was about 1.3%. Aluminum cingulum array loads with self-accommodating structure were prepared using the aluminum cingulum cut by laser, and the self-accommodating quantity was up to 4.5 mm which could meet the need of Qiangguang-Ⅰ facility physical experiment.
2014,
26: 072005.
doi: 10.11884/HPLPB201426.072005
Abstract:
The porous sol-gel silica film was prepared on silicon substrate by the dip coating process. Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of silica was investigated for the thickness and refractive index of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the film thickness increased with the withdrawal speed for the same colloid concentration. Linear relation between film thickness and withdrawal speed was better than power function relation for describing the experiment data. The refractive index of the film decreased with the withdrawal speed. For the same thickness, the refractive index of the film increased with the concentration of silica. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and concentration of silica.
The porous sol-gel silica film was prepared on silicon substrate by the dip coating process. Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of silica was investigated for the thickness and refractive index of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the film thickness increased with the withdrawal speed for the same colloid concentration. Linear relation between film thickness and withdrawal speed was better than power function relation for describing the experiment data. The refractive index of the film decreased with the withdrawal speed. For the same thickness, the refractive index of the film increased with the concentration of silica. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and concentration of silica.
2014,
26: 072006.
doi: 10.11884/HPLPB201426.072006
Abstract:
In the presence of relativistic, wakefield driven by the ponderomotive force and nonlinear polarization effects, the propagation characteristics of an intense short laser pulse in a partially stripped plasma are investigated. The evolution equation of the laser spot size is derived using variational technique. The matched parameters of laser and plasma for propagation with constant spot size are identified using the nonlinear dynamics. It is found that the laser focusing is enhanced in partially stripped plasma as compared to fully ionized plasma and also by the wakefield effects. The laser intensity for focusing dominates over the plasma density in partially stripped plasma. The results may be significant theoretically to the mechanism of ionization-induced injection and acceleration by an intense short laser.
In the presence of relativistic, wakefield driven by the ponderomotive force and nonlinear polarization effects, the propagation characteristics of an intense short laser pulse in a partially stripped plasma are investigated. The evolution equation of the laser spot size is derived using variational technique. The matched parameters of laser and plasma for propagation with constant spot size are identified using the nonlinear dynamics. It is found that the laser focusing is enhanced in partially stripped plasma as compared to fully ionized plasma and also by the wakefield effects. The laser intensity for focusing dominates over the plasma density in partially stripped plasma. The results may be significant theoretically to the mechanism of ionization-induced injection and acceleration by an intense short laser.
2014,
26: 072007.
doi: 10.11884/HPLPB201426.072007
Abstract:
Laser-driven reservoir can be used to generate quasi-isentropic compression. In this paper, a method is proposed to estimate the pressure at the front of the sample. When laser-driven shock wave relaxes after reaching the rear surface of reservoir, the generated plasma expands in the vacuum, and ultimately piles up at the front of the sample with low pressure and temperature, and in time period longer than that without vacuum. Assuming the unloading reservoir as a poly-tropic gas, and dividing it into several layers, the analytic self-similar solution is obtained for every layer to describe the velocity, pressure, and density of the plasma expansion into the vacuum. With the solutions, a computation code is given to calculate the time dependent pressure. Compared with the experimental back integrated results, the simplified model is reasonable to estimate pressure at the front of the sample.
Laser-driven reservoir can be used to generate quasi-isentropic compression. In this paper, a method is proposed to estimate the pressure at the front of the sample. When laser-driven shock wave relaxes after reaching the rear surface of reservoir, the generated plasma expands in the vacuum, and ultimately piles up at the front of the sample with low pressure and temperature, and in time period longer than that without vacuum. Assuming the unloading reservoir as a poly-tropic gas, and dividing it into several layers, the analytic self-similar solution is obtained for every layer to describe the velocity, pressure, and density of the plasma expansion into the vacuum. With the solutions, a computation code is given to calculate the time dependent pressure. Compared with the experimental back integrated results, the simplified model is reasonable to estimate pressure at the front of the sample.
2014,
26: 072008.
doi: 10.11884/HPLPB201426.072008
Abstract:
To satisfy requirement of polyimide(PI) capsules for inertial confinement fusion (ICF) targets, influence of monomer heating temperature on the thin film, thickness uniformity and surface quality of shells treated by impulse tapping, configuration of PI after curing process and heating stabilization were investigated. The results show that composite shells root-mean-square value ranged from 29 nm to 45 nm by impulse tapping, which is close to ICF standard. The thickness of films is less than 1 m in both vertical and lateral directions, which is uniform. After the curing process, PAA is converted to PI. CONH is combined with COOH to form C-N. The thermal stability of films is well, which greatly deforms at 600 ℃ and still reserves 20% at 900 ℃.
To satisfy requirement of polyimide(PI) capsules for inertial confinement fusion (ICF) targets, influence of monomer heating temperature on the thin film, thickness uniformity and surface quality of shells treated by impulse tapping, configuration of PI after curing process and heating stabilization were investigated. The results show that composite shells root-mean-square value ranged from 29 nm to 45 nm by impulse tapping, which is close to ICF standard. The thickness of films is less than 1 m in both vertical and lateral directions, which is uniform. After the curing process, PAA is converted to PI. CONH is combined with COOH to form C-N. The thermal stability of films is well, which greatly deforms at 600 ℃ and still reserves 20% at 900 ℃.
2014,
26: 072009.
doi: 10.11884/HPLPB201426.072009
Abstract:
In this paper, the active velocity interferometer system for any reflector has been presented to adjust the thickness change. The expansion was calculated under different laser energy and target design. The experiment shows, the expansion is about 2.1 m under 5 kJ indirect single-ended drive. The thickness change can be obtained after calculating the fringe change. After the optimization of target design in double-ended drive experiment, the step thickness can be achieved accurately with corrected preheat effect on the thickness. The time for shock wave breaking out on the step target can be achieved with the optical stream camera. Under the condition of steady velocity in step target, the shock wave velocity can be gotten from the experiment data. This technique is suitable for the shock wave experiment with radiation drive, and provided the shock wave for equation of state with high accurate.
In this paper, the active velocity interferometer system for any reflector has been presented to adjust the thickness change. The expansion was calculated under different laser energy and target design. The experiment shows, the expansion is about 2.1 m under 5 kJ indirect single-ended drive. The thickness change can be obtained after calculating the fringe change. After the optimization of target design in double-ended drive experiment, the step thickness can be achieved accurately with corrected preheat effect on the thickness. The time for shock wave breaking out on the step target can be achieved with the optical stream camera. Under the condition of steady velocity in step target, the shock wave velocity can be gotten from the experiment data. This technique is suitable for the shock wave experiment with radiation drive, and provided the shock wave for equation of state with high accurate.
2014,
26: 072010.
doi: 10.11884/HPLPB201426.072010
Abstract:
The paper presents the advanced manufacturing process of crystals which are extensively used in high-power laser devices. Based on the properties of the typical LBO and YCOB crystals, a procedure including cutting, grinding, pre-polishing, MRF polishing, composite lap polishing and CMP polishing was proposed. Experiments were undertaken for various crystals and correlative manufacturing technologies were studied. Different polishing approaches were used, in which the MRF process was employed for LBO crystal and the composite lap polishing process was utilized for YCOB crystal. The results show that, by combining the manufacturing technologies, the surface figure and roughness of LBO reached 0.12 and 0.77 nm, and the surface figure and roughness of YCOB reached 0.11 and 0.68 nm respectively.
The paper presents the advanced manufacturing process of crystals which are extensively used in high-power laser devices. Based on the properties of the typical LBO and YCOB crystals, a procedure including cutting, grinding, pre-polishing, MRF polishing, composite lap polishing and CMP polishing was proposed. Experiments were undertaken for various crystals and correlative manufacturing technologies were studied. Different polishing approaches were used, in which the MRF process was employed for LBO crystal and the composite lap polishing process was utilized for YCOB crystal. The results show that, by combining the manufacturing technologies, the surface figure and roughness of LBO reached 0.12 and 0.77 nm, and the surface figure and roughness of YCOB reached 0.11 and 0.68 nm respectively.
2014,
26: 072011.
doi: 10.11884/HPLPB201426.072011
Abstract:
Polishing-induced redeposition layer of fused silica optics seriously limits the laser damage resistance, and currently the focus of research lies in absorbing impurities. This article focuses on structure characterization of fused silica redeposition layer in nanoscale and analysis of impurities. With atomic force microscopy to observe surface morphology of fused silica at different etching time and using secondary ion mass spectroscopy, such redeposition layer structure and impurity distribution are investigated. The results indicate that a large number of microcracks and impurities existing in redeposition layer within 10 nm deep are formed into nanoscale scratches and pits after etching, which decay exponentially with depth. The thickness of the redeposition layer is estimated based on the evolution of nanoscale scratches density and aspect ratio with etching depth, which is basically consistent with the depth of embedded impurities measured by secondary ion mass spectroscopy. Correlation between depth of embedded impurities and distribution of polishing microcracks shows that impurities are more likely to hide in the polishing microcracks.
Polishing-induced redeposition layer of fused silica optics seriously limits the laser damage resistance, and currently the focus of research lies in absorbing impurities. This article focuses on structure characterization of fused silica redeposition layer in nanoscale and analysis of impurities. With atomic force microscopy to observe surface morphology of fused silica at different etching time and using secondary ion mass spectroscopy, such redeposition layer structure and impurity distribution are investigated. The results indicate that a large number of microcracks and impurities existing in redeposition layer within 10 nm deep are formed into nanoscale scratches and pits after etching, which decay exponentially with depth. The thickness of the redeposition layer is estimated based on the evolution of nanoscale scratches density and aspect ratio with etching depth, which is basically consistent with the depth of embedded impurities measured by secondary ion mass spectroscopy. Correlation between depth of embedded impurities and distribution of polishing microcracks shows that impurities are more likely to hide in the polishing microcracks.
2014,
26: 073001.
doi: 10.11884/HPLPB201426.073001
Abstract:
Compact configuration and self-establishment of all-inductive isolated repetition frequency Marx generator is performed by improving the total circuit and key element arrange. Switches to ground and coupler of the oscillator are well-designed, and the output power of the oscillator is increased. Through experiments, the following qualifications of the wide-band source is concluded, the wide spectrum radiation factor is 175 kV, the repetition frequency is 20 Hz, the center radiation frequency is 300 MHz, the spectrum width is 22%, the volume is less than 0.2 m3, and the weight is about 200 kg. The system is integrated, movable, 360 rotatable, and can be controlled remotely.
Compact configuration and self-establishment of all-inductive isolated repetition frequency Marx generator is performed by improving the total circuit and key element arrange. Switches to ground and coupler of the oscillator are well-designed, and the output power of the oscillator is increased. Through experiments, the following qualifications of the wide-band source is concluded, the wide spectrum radiation factor is 175 kV, the repetition frequency is 20 Hz, the center radiation frequency is 300 MHz, the spectrum width is 22%, the volume is less than 0.2 m3, and the weight is about 200 kg. The system is integrated, movable, 360 rotatable, and can be controlled remotely.
2014,
26: 073002.
doi: 10.11884/HPLPB201426.073002
Abstract:
An X-band high power microwave leaky-wave-antenna array with one-dimension scanning capability is introduced in this paper. The antenna contains an 8-elements leaky-wave waveguide array, a 1-8 port power divider, and eight high power phase shifters. The gain of the leaky-wave array is 29.6 dB, and the aperture efficiency is 70%. The divider first converts the TM01 mode of circular waveguide into TE01 mode of rectangular waveguide, then divides the input power into eight ports with cascaded power split waveguide branch. Differences between the output ports are less than 0.16 dB, the power handling capacity is 1.1 GW. The phase shifter is realized by changing the width of the rectangular waveguide with a flexible brass reed, the power handling capacity is 150 MW per shifter when it works under vacuum environment. The beam scanning angle of the antenna system is ranged from -40 to 40 with a gain loss of -3 dB as simulation result shows.
An X-band high power microwave leaky-wave-antenna array with one-dimension scanning capability is introduced in this paper. The antenna contains an 8-elements leaky-wave waveguide array, a 1-8 port power divider, and eight high power phase shifters. The gain of the leaky-wave array is 29.6 dB, and the aperture efficiency is 70%. The divider first converts the TM01 mode of circular waveguide into TE01 mode of rectangular waveguide, then divides the input power into eight ports with cascaded power split waveguide branch. Differences between the output ports are less than 0.16 dB, the power handling capacity is 1.1 GW. The phase shifter is realized by changing the width of the rectangular waveguide with a flexible brass reed, the power handling capacity is 150 MW per shifter when it works under vacuum environment. The beam scanning angle of the antenna system is ranged from -40 to 40 with a gain loss of -3 dB as simulation result shows.
2014,
26: 073003.
doi: 10.11884/HPLPB201426.073003
Abstract:
Distribution of magnetic field inside the solenoidal coil is calculated by using Simpson algorithm. It is proved that the off-axis magnetic field can be used for bunching the electron beam. With the aid of 2D particle-in-cell code, an X-band five-cavity high-gain klystron amplifier is designed with an output power of 299.46 MW, a frequency of 9.45 GHz, a gain of 50.3 dB and an efficiency 37.4% respectively. Three-dimensional model of device placed on the coil central axis and off-axis is designed. And the simulation result demonstrates that the off-axiss device can amplify microwave signal. Seven tubes are placed inside one solenoidal coil simultaneously, the simulated result shows that synthetic power can reach 2 GW theoretically.
Distribution of magnetic field inside the solenoidal coil is calculated by using Simpson algorithm. It is proved that the off-axis magnetic field can be used for bunching the electron beam. With the aid of 2D particle-in-cell code, an X-band five-cavity high-gain klystron amplifier is designed with an output power of 299.46 MW, a frequency of 9.45 GHz, a gain of 50.3 dB and an efficiency 37.4% respectively. Three-dimensional model of device placed on the coil central axis and off-axis is designed. And the simulation result demonstrates that the off-axiss device can amplify microwave signal. Seven tubes are placed inside one solenoidal coil simultaneously, the simulated result shows that synthetic power can reach 2 GW theoretically.
2014,
26: 073101.
doi: 10.11884/HPLPB201426.073101
Abstract:
A new numerical nonlinear theory based on 1D electronic-discs model for an extended interaction oscillator (EIO) is developed in this paper. Combining MAGIC simulation, the cold cavity and hot cavity features of EIO are tested. 35 GHz EIO could generate 125 W on 35.01 GHz in nonlinear simulation and 100 W on 35.11 GHz in MAGIC simulation. 110 GHz EIO could generate 220 W on 107.9 GHz in nonlinear simulation and 190 W on 107.93 GHz in MAGIC simulation. The nonlinear theory approach has a significant advantage of quick calculation that each calculation time is less than 5 minutes, and it could get similar results with the MAGIC simulation.
A new numerical nonlinear theory based on 1D electronic-discs model for an extended interaction oscillator (EIO) is developed in this paper. Combining MAGIC simulation, the cold cavity and hot cavity features of EIO are tested. 35 GHz EIO could generate 125 W on 35.01 GHz in nonlinear simulation and 100 W on 35.11 GHz in MAGIC simulation. 110 GHz EIO could generate 220 W on 107.9 GHz in nonlinear simulation and 190 W on 107.93 GHz in MAGIC simulation. The nonlinear theory approach has a significant advantage of quick calculation that each calculation time is less than 5 minutes, and it could get similar results with the MAGIC simulation.
2014,
26: 073102.
doi: 10.11884/HPLPB201426.073102
Abstract:
The THz image enhancement, segmentation and contour extraction algorithms are studied to achieve effective target image detection. Firstly, the terahertz images are enhanced and their grayscales are stretched. Then we apply global threshold segmentation to extracting the target, and finally the targets are marked on the visible image. The experimental results show that the algorithm proposed in this paper can extract and mark targets effectively, so that people can find suspicious objects under clothing more quickly. The algorithm can improve the usefulness of the terahertz security apparatus we have developed.
The THz image enhancement, segmentation and contour extraction algorithms are studied to achieve effective target image detection. Firstly, the terahertz images are enhanced and their grayscales are stretched. Then we apply global threshold segmentation to extracting the target, and finally the targets are marked on the visible image. The experimental results show that the algorithm proposed in this paper can extract and mark targets effectively, so that people can find suspicious objects under clothing more quickly. The algorithm can improve the usefulness of the terahertz security apparatus we have developed.
2014,
26: 073103.
doi: 10.11884/HPLPB201426.073103
Abstract:
A method for analyzing THz time-domain spectroscopy based on Hilbert-Huang transform(HHT) was presented. THz pulse of vapor can be decomposed into a number of signals with single frequency, and using Hilbert transform to those components can acquire the instantaneous frequency. The final presentation of those results is an energy-frequency-time distribution, designated as the HHT spectrum, which is compared with the time-frequency distribution based on wavelet transform. The results indicate that the method can improve the temporal resolution and frequency resolution, and it has the feature of localization analysis and adaptive selection. The HHT based THz-TDS is feasible in researching the mechanism on interaction of THz with materials by time-domain and frequency-domain.
A method for analyzing THz time-domain spectroscopy based on Hilbert-Huang transform(HHT) was presented. THz pulse of vapor can be decomposed into a number of signals with single frequency, and using Hilbert transform to those components can acquire the instantaneous frequency. The final presentation of those results is an energy-frequency-time distribution, designated as the HHT spectrum, which is compared with the time-frequency distribution based on wavelet transform. The results indicate that the method can improve the temporal resolution and frequency resolution, and it has the feature of localization analysis and adaptive selection. The HHT based THz-TDS is feasible in researching the mechanism on interaction of THz with materials by time-domain and frequency-domain.
2014,
26: 073201.
doi: 10.11884/HPLPB201426.073201
Abstract:
This paper analyzes the unmanned aerial vehicle(UAV) hierarchy and complex electromagnetic environment effects on UAV, and an efficiency evaluation index system of UAV in complex electromagnetic environment is established, the indexes are obtained using subjective weighting method and objective weighting method. Considering the fuzziness and uncertainty of UAV system indexes, the cloud model is used to get the combination between the qualitative and quantitative attributes of indexes, which effectively combines the fuzziness and uncertainty factors in the course of evaluation, and the total effectiveness of UAV in complex electromagnetic environment system is fitted using evaluation level cloud model. Finally, the method of effectiveness evaluation of UAV in complex electromagnetic environment is established based on cloud model, which provides a reference foundation for the quantitative efficiency evaluation of UAV in complex electromagnetic environment.
This paper analyzes the unmanned aerial vehicle(UAV) hierarchy and complex electromagnetic environment effects on UAV, and an efficiency evaluation index system of UAV in complex electromagnetic environment is established, the indexes are obtained using subjective weighting method and objective weighting method. Considering the fuzziness and uncertainty of UAV system indexes, the cloud model is used to get the combination between the qualitative and quantitative attributes of indexes, which effectively combines the fuzziness and uncertainty factors in the course of evaluation, and the total effectiveness of UAV in complex electromagnetic environment system is fitted using evaluation level cloud model. Finally, the method of effectiveness evaluation of UAV in complex electromagnetic environment is established based on cloud model, which provides a reference foundation for the quantitative efficiency evaluation of UAV in complex electromagnetic environment.
2014,
26: 073202.
doi: 10.11884/HPLPB201426.073202
Abstract:
The complex electromagnetic environmental effects (E3) test and evaluation (TE), as described in MIL-HDBK-237D, are discussed of military platforms, systems, subsystems, or equipment in acquisition life cycle processes. With the analysis of complex military electromagnetic environment (EME) including radiated and conducted emissions from intentional and unintentional sources, the methods for complex EME adaptability or immunity developmental test and evaluation(DTE) and operational test and evaluation(OTE) are proposed either to assure visibility, accountability, or to assure management awareness and establish complex military EME performance TE standards.
The complex electromagnetic environmental effects (E3) test and evaluation (TE), as described in MIL-HDBK-237D, are discussed of military platforms, systems, subsystems, or equipment in acquisition life cycle processes. With the analysis of complex military electromagnetic environment (EME) including radiated and conducted emissions from intentional and unintentional sources, the methods for complex EME adaptability or immunity developmental test and evaluation(DTE) and operational test and evaluation(OTE) are proposed either to assure visibility, accountability, or to assure management awareness and establish complex military EME performance TE standards.
2014,
26: 073203.
doi: 10.11884/HPLPB201426.073203
Abstract:
In this paper, carbon fibers were plated with the chemical nickel plating method. The microstructure of the nickel-plated carbon fibers, the nickel layer composition and its structures were studied by the scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction techniques. The conductivities of the nickel-plated carbon fibers and its composites were tested with broadband resistance voltage instrument. The high power microwave(HPM) shielding effectiveness of the composites were also measured with 1.3 GHz, 2.8 GHz, 4.3 GHz, 9.4 GHz at the electric field intensity equal or greater than 20 kV/m. The results reveal that the HPM shielding effectiveness of the nickel-plated carbon fiber composites is more than 60 dB, and the maximum value is 91 dB with 2.8 GHz.
In this paper, carbon fibers were plated with the chemical nickel plating method. The microstructure of the nickel-plated carbon fibers, the nickel layer composition and its structures were studied by the scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction techniques. The conductivities of the nickel-plated carbon fibers and its composites were tested with broadband resistance voltage instrument. The high power microwave(HPM) shielding effectiveness of the composites were also measured with 1.3 GHz, 2.8 GHz, 4.3 GHz, 9.4 GHz at the electric field intensity equal or greater than 20 kV/m. The results reveal that the HPM shielding effectiveness of the nickel-plated carbon fiber composites is more than 60 dB, and the maximum value is 91 dB with 2.8 GHz.
2014,
26: 073204.
doi: 10.11884/HPLPB201426.073204
Abstract:
A modeling approach for electromagnetic field coupling to a microstrip line connected with nonlinear component is proposed firstly. On this basis, a system-level analysis method of electromagnetic effects on an electronic system containing nonlinear components is presented. Nonlinear scattering parameters based on a black-box model are used to represent the nonlinear behavior of components, and can be extracted from measurement. Finally, the proposed method is experimentally validated by a laboratory system including a simple nonlinear component, which is constituted by the anti-paralleled HSMS-282C Schottky diodes pair welded to a 50 microstrip line. The calculated results using the proposed method show good agreements with the measured data.
A modeling approach for electromagnetic field coupling to a microstrip line connected with nonlinear component is proposed firstly. On this basis, a system-level analysis method of electromagnetic effects on an electronic system containing nonlinear components is presented. Nonlinear scattering parameters based on a black-box model are used to represent the nonlinear behavior of components, and can be extracted from measurement. Finally, the proposed method is experimentally validated by a laboratory system including a simple nonlinear component, which is constituted by the anti-paralleled HSMS-282C Schottky diodes pair welded to a 50 microstrip line. The calculated results using the proposed method show good agreements with the measured data.
2014,
26: 073205.
doi: 10.11884/HPLPB201426.073205
Abstract:
The statistic characteristic of induced voltages at key points in computer box cavity is researched by means of experiments and the random coupling model （RCM）. It is shown that the experiment results generally agree with the theoretical results in trend. The applicability of RCM in analysis and predication of system-level electromagnetic environment effects is validated. A new method based on statistical electromagnetism should be exploited for the analyses of electromagnetic effects for large scale nonparallel surface electron device-box cavity systems.
The statistic characteristic of induced voltages at key points in computer box cavity is researched by means of experiments and the random coupling model （RCM）. It is shown that the experiment results generally agree with the theoretical results in trend. The applicability of RCM in analysis and predication of system-level electromagnetic environment effects is validated. A new method based on statistical electromagnetism should be exploited for the analyses of electromagnetic effects for large scale nonparallel surface electron device-box cavity systems.
2014,
26: 073206.
doi: 10.11884/HPLPB201426.073206
Abstract:
The inverse synthetic aperture radar (ISAR) imaging of a target in a complex environment was studied in this paper. Firstly, the radar echo from the target underlying a complex environment has been simulated by using the computational electromagnetics, where the interactions from its environment have been taken into account. It was found that the imaging quality will be affected by the environment scattering. Secondly, a new simulation model based on the compressive sensing (CS) algorithm was proposed, which greatly reduces the computational costs of radar echo simulation. Corresponding experiments show that the imaging quality achieved with the data utilzation rate of 0.4 in CS model can reach the same level of traditional ISAR imaging. Therefore, this model can reconstruct the image by using fewer data points, which makes the electromagnetic simulation and ISAR imaging of target under complex environment possible.
The inverse synthetic aperture radar (ISAR) imaging of a target in a complex environment was studied in this paper. Firstly, the radar echo from the target underlying a complex environment has been simulated by using the computational electromagnetics, where the interactions from its environment have been taken into account. It was found that the imaging quality will be affected by the environment scattering. Secondly, a new simulation model based on the compressive sensing (CS) algorithm was proposed, which greatly reduces the computational costs of radar echo simulation. Corresponding experiments show that the imaging quality achieved with the data utilzation rate of 0.4 in CS model can reach the same level of traditional ISAR imaging. Therefore, this model can reconstruct the image by using fewer data points, which makes the electromagnetic simulation and ISAR imaging of target under complex environment possible.
2014,
26: 073207.
doi: 10.11884/HPLPB201426.073207
Abstract:
Analysis of technical problem is presented on the laboratory experimental simulation techniques on the system generated electromagnetic pulse (SGEMP) effects of transient X-ray. And a new method for effective measurement of the SGEMP effects and the experimental simulation method of SGEMP effects to transient -ray are proposed. By certain designs, such as electrons shield, electromagnetism shield, photo-electricity insulation, and signal symmetrical process, X-ray hardness and anti-electromagnetic interference are solved in the measurement system. Under the irradiation of a large scale transient pulse X-ray simulation source, the measurement system can measure fairly good waveforms of SGEMP effects of the cables.
Analysis of technical problem is presented on the laboratory experimental simulation techniques on the system generated electromagnetic pulse (SGEMP) effects of transient X-ray. And a new method for effective measurement of the SGEMP effects and the experimental simulation method of SGEMP effects to transient -ray are proposed. By certain designs, such as electrons shield, electromagnetism shield, photo-electricity insulation, and signal symmetrical process, X-ray hardness and anti-electromagnetic interference are solved in the measurement system. Under the irradiation of a large scale transient pulse X-ray simulation source, the measurement system can measure fairly good waveforms of SGEMP effects of the cables.
2014,
26: 073208.
doi: 10.11884/HPLPB201426.073208
Abstract:
The traditional parameters estimating methods of maximum field distribution in chaotic electric field are the approximate normal method, percentile method and BC-t method, which all lead to kind of error when used in small samples and non-normal distribution. We make a careful analysis of the chaotic maximum field distribution and generalized extreme value distribution theory, and then a hybrid algorithm about the chaotic maximum field distribution is presented which based on Bootstrap resample technique, and it is found that this method is more practical and veracious through Monte Carlo simulation and reverberation chamber testing.
The traditional parameters estimating methods of maximum field distribution in chaotic electric field are the approximate normal method, percentile method and BC-t method, which all lead to kind of error when used in small samples and non-normal distribution. We make a careful analysis of the chaotic maximum field distribution and generalized extreme value distribution theory, and then a hybrid algorithm about the chaotic maximum field distribution is presented which based on Bootstrap resample technique, and it is found that this method is more practical and veracious through Monte Carlo simulation and reverberation chamber testing.
2014,
26: 073209.
doi: 10.11884/HPLPB201426.073209
Abstract:
To understand distribution characteristics of electromagnetic field in the building under near- and far-field radiation by narrow band electromagnetic pulse, computation results of multiple-storey multi-unit building under oblique incidence of plane and spherical electromagnetic waves are comparatively analyzed by finite-difference time-domain(FDTD) method. The electrical field amplitude at centers of different altitude planes in room and the maximum distribution of electrical field strength at different altitude planes in building are generally analyzed. The field distribution of corresponding altitude planes on each floor in building is similar. The field strength of areas where the incident wave propagates from windows into rooms is stronger, and is identical under the incidence of both kinds of electromagnetic waves. The field strength of the rest areas in wider space under incidence of spherical wave is weaker than that under incidence of plane wave. By used of the field source with spherical electromagnetic wave closely fitting the building form, the spherical wave of narrow band propagating in empty space is simulated, and computation results prove the field source of spherical wave constructed accurately workable.
To understand distribution characteristics of electromagnetic field in the building under near- and far-field radiation by narrow band electromagnetic pulse, computation results of multiple-storey multi-unit building under oblique incidence of plane and spherical electromagnetic waves are comparatively analyzed by finite-difference time-domain(FDTD) method. The electrical field amplitude at centers of different altitude planes in room and the maximum distribution of electrical field strength at different altitude planes in building are generally analyzed. The field distribution of corresponding altitude planes on each floor in building is similar. The field strength of areas where the incident wave propagates from windows into rooms is stronger, and is identical under the incidence of both kinds of electromagnetic waves. The field strength of the rest areas in wider space under incidence of spherical wave is weaker than that under incidence of plane wave. By used of the field source with spherical electromagnetic wave closely fitting the building form, the spherical wave of narrow band propagating in empty space is simulated, and computation results prove the field source of spherical wave constructed accurately workable.
2014,
26: 073210.
doi: 10.11884/HPLPB201426.073210
Abstract:
The directional side scattering of nanoantennas is significant to many research fields, such as biological sensing, and surface enhanced spectroscopy. The antennas mirror symmetry has to be broken relative to the light polarization for generating directional side scattering. Since the nanoantenna composed of nanoparticle array has flexible configuration, it is easy for the antenna to break mirror symmetry. The V-shaped antenna composed of gold nanosphere array was simulated with T-matrix method and the directivity of its side scattering was considered. We discussed the effects of some parameters on the directional side scattering of V-nanoantennas, such as the arm length with different number of nanospheres, opening angle, sphere radius, and distance between adjacent sphere centers. Our discussion shows the directional side scattering of V-nanoantennas composed of nanosphere array is tunable.
The directional side scattering of nanoantennas is significant to many research fields, such as biological sensing, and surface enhanced spectroscopy. The antennas mirror symmetry has to be broken relative to the light polarization for generating directional side scattering. Since the nanoantenna composed of nanoparticle array has flexible configuration, it is easy for the antenna to break mirror symmetry. The V-shaped antenna composed of gold nanosphere array was simulated with T-matrix method and the directivity of its side scattering was considered. We discussed the effects of some parameters on the directional side scattering of V-nanoantennas, such as the arm length with different number of nanospheres, opening angle, sphere radius, and distance between adjacent sphere centers. Our discussion shows the directional side scattering of V-nanoantennas composed of nanosphere array is tunable.
2014,
26: 073211.
doi: 10.11884/HPLPB201426.073211
Abstract:
To quickly predict the characteristic of the electromagnetic environment in two-dimensional terrain environment, this paper uses the two-dimensional parabolic equation model to simulate the electromagnetic environment. In order to get the real and effective terrain information, this paper studies the method to extract the grids terrain information from the GeoTiff, then uses the bilinear interpolation method to obtain the elevation value of the arbitrary location on the terrain profile. The calculation method of distance between two points on the Earths surface is also studied, and the results obtained by this method are compared with those obtained by the GIS software, which verifies the accuracy of the method. In the standard atmosphere condition, this paper uses the two-dimensional parabolic equation model to simulate and analyze the variation of the radio wave propagation factor with height in different distance and offers an efficient method to predict the characteristics of the wave propagation in the real terrain environment.
To quickly predict the characteristic of the electromagnetic environment in two-dimensional terrain environment, this paper uses the two-dimensional parabolic equation model to simulate the electromagnetic environment. In order to get the real and effective terrain information, this paper studies the method to extract the grids terrain information from the GeoTiff, then uses the bilinear interpolation method to obtain the elevation value of the arbitrary location on the terrain profile. The calculation method of distance between two points on the Earths surface is also studied, and the results obtained by this method are compared with those obtained by the GIS software, which verifies the accuracy of the method. In the standard atmosphere condition, this paper uses the two-dimensional parabolic equation model to simulate and analyze the variation of the radio wave propagation factor with height in different distance and offers an efficient method to predict the characteristics of the wave propagation in the real terrain environment.
2014,
26: 073212.
doi: 10.11884/HPLPB201426.073212
Abstract:
When voltage and current signals transmit on transmission lines, it can produce crosstalk responses on the other transmission lines. In this paper, the time domain BLT equation is used to set up the crosstalk model of multi-conductor transmission lines to multi-conductor transmission lines, and analyze the crosstalk voltage responses on the terminal loads of victim lines excited by different number of sine wave sources at different frequencies. The research results show that the number of main frequency of crosstalk voltage responses on terminal loads of victim lines is equal to the number of lumped voltage sources. The frequencies of crosstalk voltage responses are same with those of lumped voltage sources. The amplitudes of crosstalk voltage responses are concerned with the distance between lumped voltage sources and victim transmission lines.
When voltage and current signals transmit on transmission lines, it can produce crosstalk responses on the other transmission lines. In this paper, the time domain BLT equation is used to set up the crosstalk model of multi-conductor transmission lines to multi-conductor transmission lines, and analyze the crosstalk voltage responses on the terminal loads of victim lines excited by different number of sine wave sources at different frequencies. The research results show that the number of main frequency of crosstalk voltage responses on terminal loads of victim lines is equal to the number of lumped voltage sources. The frequencies of crosstalk voltage responses are same with those of lumped voltage sources. The amplitudes of crosstalk voltage responses are concerned with the distance between lumped voltage sources and victim transmission lines.
2014,
26: 073213.
doi: 10.11884/HPLPB201426.073213
Abstract:
This paper demonstrates a massively parallel 3D full-wave electromagnetic field simulation program JEMS-FDTD and its application in complicated electromagnetic environment study. Two numerical examples of application are presented. The computation of radio wave propagation in actual building produces the numerical results of the propagation process of electromagnetic pulse in time domain, which can be used to analyze the characteristics of indoor radio propagation and electromagnetic environment safety. The computation of aircraft transient electromagnetic characteristics gives the transient electromagnetic field distribution inside and outside the compartments, which can be used in HIRF (High Intensity Radiation Field) protection study.
This paper demonstrates a massively parallel 3D full-wave electromagnetic field simulation program JEMS-FDTD and its application in complicated electromagnetic environment study. Two numerical examples of application are presented. The computation of radio wave propagation in actual building produces the numerical results of the propagation process of electromagnetic pulse in time domain, which can be used to analyze the characteristics of indoor radio propagation and electromagnetic environment safety. The computation of aircraft transient electromagnetic characteristics gives the transient electromagnetic field distribution inside and outside the compartments, which can be used in HIRF (High Intensity Radiation Field) protection study.
2014,
26: 073214.
doi: 10.11884/HPLPB201426.073214
Abstract:
In this paper, we use the Constant-transform method to get the solution of the nonhomogeneous linear differential equations from Taylor model for a two-wire line in frequency domain. The solutions for the load current and voltage are equal to the results of the BLT equations. We give an analytic solution to the load voltage in response to an electromagnetic interference on two parallel striplines, and get the incident direction and polarized direction in which the electromagnetic wave dont cause interference voltage on the load of the two parallel striplines.
In this paper, we use the Constant-transform method to get the solution of the nonhomogeneous linear differential equations from Taylor model for a two-wire line in frequency domain. The solutions for the load current and voltage are equal to the results of the BLT equations. We give an analytic solution to the load voltage in response to an electromagnetic interference on two parallel striplines, and get the incident direction and polarized direction in which the electromagnetic wave dont cause interference voltage on the load of the two parallel striplines.
2014,
26: 073215.
doi: 10.11884/HPLPB201426.073215
Abstract:
In this paper, we introduce the blind source separation(BSS) based signal processing idea, its mathematical model and three typical algorithmsICA, SOBI and AMUSE. We also study the performance of the three algorithms using common waveform signals and the true signals. The experiments indicate that the algorithms are effective and feasible for suppressing interfering signals and extracting useful signals.
In this paper, we introduce the blind source separation(BSS) based signal processing idea, its mathematical model and three typical algorithmsICA, SOBI and AMUSE. We also study the performance of the three algorithms using common waveform signals and the true signals. The experiments indicate that the algorithms are effective and feasible for suppressing interfering signals and extracting useful signals.
2014,
26: 073216.
doi: 10.11884/HPLPB201426.073216
Abstract:
In complex electromagnetic environment, a lot of signals are missing and many parameters of signals have severe superposition. The orderliness of signals are destroyed, making the existing sorting methods unsatisfactory and even disabled completely. This paper studies the important signal parameters(PW，RF and TOA) and introduces the five-step sorting methods. It is important that using the character extraction methods, the character vectors can be mined and the corresponding models of mathematics can be made. Finally, we can achieve all the kinds of signal sorting. The results of simulations show that the five-step sorting method can be used to sort the mixed signals with losing data and severe superposition.
In complex electromagnetic environment, a lot of signals are missing and many parameters of signals have severe superposition. The orderliness of signals are destroyed, making the existing sorting methods unsatisfactory and even disabled completely. This paper studies the important signal parameters(PW，RF and TOA) and introduces the five-step sorting methods. It is important that using the character extraction methods, the character vectors can be mined and the corresponding models of mathematics can be made. Finally, we can achieve all the kinds of signal sorting. The results of simulations show that the five-step sorting method can be used to sort the mixed signals with losing data and severe superposition.
2014,
26: 073217.
doi: 10.11884/HPLPB201426.073217
Abstract:
By the experimental research of combined antenna, the advantages of magnetic dipole loop were verified: the loop can improve greatly low-frequency characteristic of radiation and transmission, it has the ability of low-frequency compensation. Furthermore, setting the ratio of magnetic dipole loop circumference S/S0, we compared the antenna characteristic at different status of magnetic dipole loop, found that double magnetic dipole loop had better low-frequency improvement, and single magnetic dipole loop had more advantages at high frequency.We hereby designed a combined receiving antenna with operation frequency of 300 MHz~5 GHz and structure of single magnetic dipole loop.
By the experimental research of combined antenna, the advantages of magnetic dipole loop were verified: the loop can improve greatly low-frequency characteristic of radiation and transmission, it has the ability of low-frequency compensation. Furthermore, setting the ratio of magnetic dipole loop circumference S/S0, we compared the antenna characteristic at different status of magnetic dipole loop, found that double magnetic dipole loop had better low-frequency improvement, and single magnetic dipole loop had more advantages at high frequency.We hereby designed a combined receiving antenna with operation frequency of 300 MHz~5 GHz and structure of single magnetic dipole loop.
2014,
26: 073218.
doi: 10.11884/HPLPB201426.073218
Abstract:
To understand the interference and damage effect of ultra-wideband electromagnetic pulse (UWB-EMP) on a typical radio fuze, the coupling effect of typical cavity was researched based on time domain finite integral method (FIT). Taking the cavity of typical radio fuze and low-frequency printed circuit board (PCB) as simulation model, the influences of aperture parameters, pulse parameters and PCB in cavity on coupling effect were analyzed. The results show that the coupling coefficient of rectangular aperture is affected by polarization direction obviously compared with those of circular and square apertures, and the coupling coefficient increases with the decreasing of UWB pulse rise time. Furthermore, the coupling coefficient decreases and resonance frequency changes after inserting a PCB into the cavity of the fuze.
To understand the interference and damage effect of ultra-wideband electromagnetic pulse (UWB-EMP) on a typical radio fuze, the coupling effect of typical cavity was researched based on time domain finite integral method (FIT). Taking the cavity of typical radio fuze and low-frequency printed circuit board (PCB) as simulation model, the influences of aperture parameters, pulse parameters and PCB in cavity on coupling effect were analyzed. The results show that the coupling coefficient of rectangular aperture is affected by polarization direction obviously compared with those of circular and square apertures, and the coupling coefficient increases with the decreasing of UWB pulse rise time. Furthermore, the coupling coefficient decreases and resonance frequency changes after inserting a PCB into the cavity of the fuze.
2014,
26: 073219.
doi: 10.11884/HPLPB201426.073219
Abstract:
To investigate the effects of complex electromagnetic environment on radio fuze, the method of building an environment with dual radio sources and the testing process were put forward. The electromagnetic environment effects on the radio fuze was measured, and different frequency combinations of the two sources which initiate accidental detonation of the radio fuze were studied. It is found that the signal the radio fuze antenna and projectile received was a Doppler signal, which would be mixed by an autodyne receiver oscillator, detected and filtered by a rectifier, then a sine wave with high amplitude output. With the effects of low frequency circuit, the rectification and integrating circuit, and the anti-interference inertia branch circuit, the signal would pass the amplification rate selecting circuit, then the executive circuit would be triggered, and the radio fuze would explode accidentally.
To investigate the effects of complex electromagnetic environment on radio fuze, the method of building an environment with dual radio sources and the testing process were put forward. The electromagnetic environment effects on the radio fuze was measured, and different frequency combinations of the two sources which initiate accidental detonation of the radio fuze were studied. It is found that the signal the radio fuze antenna and projectile received was a Doppler signal, which would be mixed by an autodyne receiver oscillator, detected and filtered by a rectifier, then a sine wave with high amplitude output. With the effects of low frequency circuit, the rectification and integrating circuit, and the anti-interference inertia branch circuit, the signal would pass the amplification rate selecting circuit, then the executive circuit would be triggered, and the radio fuze would explode accidentally.
2014,
26: 073220.
doi: 10.11884/HPLPB201426.073220
Abstract:
A novel multi-layer and multi-physics co-simulation algorithm is proposed for analyzing the effect of high power microwave (HPM) on semiconductors, circuits and electronic systems. This algorithm is based on semiconductors physical model to realize the simulation of semiconductors, and the model is constituted of multi-physic equations, electromagnetic equations, semiconductor physics and thermal equations. A co-simulation method is employed, which incorporates the multi-physics simulation for semiconductors into the equivalent-model based circuit simulation, thus the simulation is extended from semiconductors to circuits. The algorithm achieves the simulation for the HPM effect on electronic systems, by incorporating the multi-physics simulation for circuits with the electromagnetic field simulation. The electronic systems include several circuits, packaging, slot coupling and cable coupling. The principle and procedure of the algorithm is introduced. The proposed algorithm is used to simulate circuits and electronic systems containing commercial P-I-N diodes for various HPM effects, including temperature effect, forward recovery effect and spatial radiation effect in a semi-enclosed cavity. By comparing the simulation results to the measurements, the feasibility and accuracy of the proposed algorithm are validated. Moreover, the proposed algorithm provides clear and intuitive interpretation of the physical mechanism for those HPM effects.
A novel multi-layer and multi-physics co-simulation algorithm is proposed for analyzing the effect of high power microwave (HPM) on semiconductors, circuits and electronic systems. This algorithm is based on semiconductors physical model to realize the simulation of semiconductors, and the model is constituted of multi-physic equations, electromagnetic equations, semiconductor physics and thermal equations. A co-simulation method is employed, which incorporates the multi-physics simulation for semiconductors into the equivalent-model based circuit simulation, thus the simulation is extended from semiconductors to circuits. The algorithm achieves the simulation for the HPM effect on electronic systems, by incorporating the multi-physics simulation for circuits with the electromagnetic field simulation. The electronic systems include several circuits, packaging, slot coupling and cable coupling. The principle and procedure of the algorithm is introduced. The proposed algorithm is used to simulate circuits and electronic systems containing commercial P-I-N diodes for various HPM effects, including temperature effect, forward recovery effect and spatial radiation effect in a semi-enclosed cavity. By comparing the simulation results to the measurements, the feasibility and accuracy of the proposed algorithm are validated. Moreover, the proposed algorithm provides clear and intuitive interpretation of the physical mechanism for those HPM effects.
2014,
26: 074001.
doi: 10.11884/HPLPB201426.074001
Abstract:
Several CVD diamond films were etched using ECR plasma in different magnetic fields and working pressure. Double probe and ion sensitive probe were used to investigate the influence of magnetic field and working pressure on etching effect. Results showed that when the divergence magnetic field was changed to the convergence one, the ion temperature, the electron temperature and the plasma density increased and the etching effect was enhanced. While the working pressure changed from a low pressure to a high pressure, the plasma parameters first increased and then decreased, a drop of the surface roughness was showed as the same trending.
Several CVD diamond films were etched using ECR plasma in different magnetic fields and working pressure. Double probe and ion sensitive probe were used to investigate the influence of magnetic field and working pressure on etching effect. Results showed that when the divergence magnetic field was changed to the convergence one, the ion temperature, the electron temperature and the plasma density increased and the etching effect was enhanced. While the working pressure changed from a low pressure to a high pressure, the plasma parameters first increased and then decreased, a drop of the surface roughness was showed as the same trending.
2014,
26: 074002.
doi: 10.11884/HPLPB201426.074002
Abstract:
Using the transmission line and drift diffusion coupling model (TLM-DDM), this paper analyzes the damage effect and mechanism of the silicon bipolar transistor induced by the cable under the X-ray pulse. The result shows that the damage effect can be decided by the lattice temperature of the bipolar transistor, and the burnout point appears first near the n-N+ interface above the center of the collector region. The paper also describes the relationships of the damage energy and burnout time with the X-ray pulse width and fluence in the curve fitting. When the pulse width of the X-ray increases, the damage energy is almost unchanged and the burnout time increases gradually. The burnout time reduces as the X-ray fluence increases, and the damage energy increases after the X-ray fluence exceeds 5.86 J/cm2.
Using the transmission line and drift diffusion coupling model (TLM-DDM), this paper analyzes the damage effect and mechanism of the silicon bipolar transistor induced by the cable under the X-ray pulse. The result shows that the damage effect can be decided by the lattice temperature of the bipolar transistor, and the burnout point appears first near the n-N+ interface above the center of the collector region. The paper also describes the relationships of the damage energy and burnout time with the X-ray pulse width and fluence in the curve fitting. When the pulse width of the X-ray increases, the damage energy is almost unchanged and the burnout time increases gradually. The burnout time reduces as the X-ray fluence increases, and the damage energy increases after the X-ray fluence exceeds 5.86 J/cm2.
2014,
26: 074003.
doi: 10.11884/HPLPB201426.074003
Abstract:
Evolutionary characteristics of radiation intensity for light flash generated by shocking strongly LY12 aluminum target were studied by the way to theoretical derivation and experiment. Experiments were performed under six kinds of experimental conditions using established optical pyrometer measurement system, which was loaded by two-stage light gas gun system. One set of optical fiber probe was used in every experiment, installed directly into impact point. Relationships of light flash radiation intensity were acquired by original data from experiment combined with calibration. Experimental results show that the power exponents of rising phase and decay phase for the light flash radiation signals were between 1 and 5 under current experimental condition and optical fiber probe scheme. The maximum light flash intensity increased with impact velocity increasing at the same incidence angles of the projectile. Variations of power exponent of maximum light flash radiation intensity produced by LY12 Aluminum projectile into LY12 aluminum target were 7.5 to 9.0 for wavelength in the range from 488 nm to 667 nm.
Evolutionary characteristics of radiation intensity for light flash generated by shocking strongly LY12 aluminum target were studied by the way to theoretical derivation and experiment. Experiments were performed under six kinds of experimental conditions using established optical pyrometer measurement system, which was loaded by two-stage light gas gun system. One set of optical fiber probe was used in every experiment, installed directly into impact point. Relationships of light flash radiation intensity were acquired by original data from experiment combined with calibration. Experimental results show that the power exponents of rising phase and decay phase for the light flash radiation signals were between 1 and 5 under current experimental condition and optical fiber probe scheme. The maximum light flash intensity increased with impact velocity increasing at the same incidence angles of the projectile. Variations of power exponent of maximum light flash radiation intensity produced by LY12 Aluminum projectile into LY12 aluminum target were 7.5 to 9.0 for wavelength in the range from 488 nm to 667 nm.
2014,
26: 074004.
doi: 10.11884/HPLPB201426.074004
Abstract:
A combination of flash photolysis reactor tube and synchrotron radiation photoionization mass spectrometer has been constructed for the study of the gas phase chemical kinetics. The radical-molecule chemical reactions in a side-sampled flow tubular reactor are initiated by a pulsed photolysis laser. Then the gas mixture is sampled via a pinpole and photoionized by tunable synchrotron radiation VUV photons. The constant flux ions are detected by the subsequent time-of-flight mass spectrometer. At the same time, pulsed generator generates a burst of pulses with duration of 40-50 s, which initiate the collection of mass spectrometer. The continuous collection covers the overall reaction time. The time resolution of mass spectrometer is 40 s, fulfilling the detection of transient or stable species on a millisecond time scale. In addition, the reaction products are directly detected by mass spectrometer and different structural isomers can be distinguished by photoionization efficiency curves. The experiment utilizing Cl radical reaction with 1-butene and isobutene obtains the addition and abstraction products as well as their photoionization energies.
A combination of flash photolysis reactor tube and synchrotron radiation photoionization mass spectrometer has been constructed for the study of the gas phase chemical kinetics. The radical-molecule chemical reactions in a side-sampled flow tubular reactor are initiated by a pulsed photolysis laser. Then the gas mixture is sampled via a pinpole and photoionized by tunable synchrotron radiation VUV photons. The constant flux ions are detected by the subsequent time-of-flight mass spectrometer. At the same time, pulsed generator generates a burst of pulses with duration of 40-50 s, which initiate the collection of mass spectrometer. The continuous collection covers the overall reaction time. The time resolution of mass spectrometer is 40 s, fulfilling the detection of transient or stable species on a millisecond time scale. In addition, the reaction products are directly detected by mass spectrometer and different structural isomers can be distinguished by photoionization efficiency curves. The experiment utilizing Cl radical reaction with 1-butene and isobutene obtains the addition and abstraction products as well as their photoionization energies.
2014,
26: 074005.
doi: 10.11884/HPLPB201426.074005
Abstract:
Based on the designed models of 90 nm, 0.13 m and 0.18 m CMOS devices, the single event latch-up (SEL) effect of different sized CMOS devices have been studied by TCAD. It shows that with the increase of process dimension of the CMOS devices, the CMOS devices will be more sensitive to SEL, while they are not SEL hardened. According to the trigger mechanism of SEL effect, two SEL preventing layouts (the structures of guard band and guard ring) were designed. Finally, the two types of structures were verified with TCAD and heavy ions facilities. The results suggest that for 90 nm and 0.13 m CMOS devices, the guard band structure is better, for 0.18 m CMOS device, the guard ring structure is recommended.
Based on the designed models of 90 nm, 0.13 m and 0.18 m CMOS devices, the single event latch-up (SEL) effect of different sized CMOS devices have been studied by TCAD. It shows that with the increase of process dimension of the CMOS devices, the CMOS devices will be more sensitive to SEL, while they are not SEL hardened. According to the trigger mechanism of SEL effect, two SEL preventing layouts (the structures of guard band and guard ring) were designed. Finally, the two types of structures were verified with TCAD and heavy ions facilities. The results suggest that for 90 nm and 0.13 m CMOS devices, the guard band structure is better, for 0.18 m CMOS device, the guard ring structure is recommended.
2014,
26: 074006.
doi: 10.11884/HPLPB201426.074006
Abstract:
Beam line 4B7A on Beijing Synchronous Radiation Facility with an energy range of 2.1 keV to 6.0 keV has an energy resolution of more than 5000, a harmonic interference of less than 0.1%, and an intensity of higher than 109 photons per second.We firstly give Ag films mass thickness by measuring its transmission in region of 2.1 keV to 6.0 keV using Henkes attenuation coefficient data. As Henkes data do not include the region of 3.4 keV to 3.9 keV, we get attenuation coefficient of Ag near absorption edges(3.4 keV to 3.9 keV) with an uncertainty of less than 1% by the mass thickness measured before and measuring X-ray transmission coefficient of the Ag film. The result could fill up the blank in attenuation coefficient in this energy range.
Beam line 4B7A on Beijing Synchronous Radiation Facility with an energy range of 2.1 keV to 6.0 keV has an energy resolution of more than 5000, a harmonic interference of less than 0.1%, and an intensity of higher than 109 photons per second.We firstly give Ag films mass thickness by measuring its transmission in region of 2.1 keV to 6.0 keV using Henkes attenuation coefficient data. As Henkes data do not include the region of 3.4 keV to 3.9 keV, we get attenuation coefficient of Ag near absorption edges(3.4 keV to 3.9 keV) with an uncertainty of less than 1% by the mass thickness measured before and measuring X-ray transmission coefficient of the Ag film. The result could fill up the blank in attenuation coefficient in this energy range.
2014,
26: 075001.
doi: 10.11884/HPLPB201426.075001
Abstract:
It is of great significance to study the characteristic of gas-liquid two-phase dielectric barrier discharge (DBD) and understand its discharge mechanism deeply for further environmental and other industrial applications. In this paper, by diagnosing voltage-current waveforms, Lissajous graphics and other electrical characteristics and optical characteristics such as emission spectra and luminescence images, the effects of different liquid components to the discharge characteristics of gas-liquid two-phase DBD at atmosphere pressure were studied. The discharge characteristics of gas-liquid two-phase DBD in aniline and aniline with NaOH solutions were compared , the experimental results were used to calculate discharge power and transmission charge, the discharge mechanism was analyzed based on discharge theory. The results show that for gas-liquid two-phase DBD in aniline solution with NaOH, the discharge characteristic was significantly different from that of pure aniline, the discharge current is about twice that of pure aniline solution at the same voltage, the luminous intensity is stronger, the discharge power and the transmission charge are larger, and at 589 nm wavelength of the spectral characteristic graph Na atomic line appears, the conductivity of the solution was increased when NaOH was added, hence gas phase discharge intensity was enhanced and the discharge became stronger.
It is of great significance to study the characteristic of gas-liquid two-phase dielectric barrier discharge (DBD) and understand its discharge mechanism deeply for further environmental and other industrial applications. In this paper, by diagnosing voltage-current waveforms, Lissajous graphics and other electrical characteristics and optical characteristics such as emission spectra and luminescence images, the effects of different liquid components to the discharge characteristics of gas-liquid two-phase DBD at atmosphere pressure were studied. The discharge characteristics of gas-liquid two-phase DBD in aniline and aniline with NaOH solutions were compared , the experimental results were used to calculate discharge power and transmission charge, the discharge mechanism was analyzed based on discharge theory. The results show that for gas-liquid two-phase DBD in aniline solution with NaOH, the discharge characteristic was significantly different from that of pure aniline, the discharge current is about twice that of pure aniline solution at the same voltage, the luminous intensity is stronger, the discharge power and the transmission charge are larger, and at 589 nm wavelength of the spectral characteristic graph Na atomic line appears, the conductivity of the solution was increased when NaOH was added, hence gas phase discharge intensity was enhanced and the discharge became stronger.
2014,
26: 075002.
doi: 10.11884/HPLPB201426.075002
Abstract:
GaAs photoconductive semiconductor switches (PCSS) triggered by laser diode were studied experimentally. Our research has focused on the effect of carrier accumulation on output properties of PCSS. The results indicate that the operation mode of PCSS depends on the carrier number and avalanche will occur when carriers accumulate to a certain level. High power output was obtained when the PCSS is triggered by an optical pulse train. Because of the carrier accumulation effect, the work conditions, i.e., the bias voltage and the optical energy, can be reduced. It is of importance to application of PCSS.
GaAs photoconductive semiconductor switches (PCSS) triggered by laser diode were studied experimentally. Our research has focused on the effect of carrier accumulation on output properties of PCSS. The results indicate that the operation mode of PCSS depends on the carrier number and avalanche will occur when carriers accumulate to a certain level. High power output was obtained when the PCSS is triggered by an optical pulse train. Because of the carrier accumulation effect, the work conditions, i.e., the bias voltage and the optical energy, can be reduced. It is of importance to application of PCSS.
2014,
26: 075003.
doi: 10.11884/HPLPB201426.075003
Abstract:
The effect of surface insulation for the tungsten planar wire arrays was studied on QiangGuang-Ⅰ facility. Utilizing the phenomena analysis, the X-ray radiation of the surface insulated wire arrays (SIWA) is considerably delayed and the delay time is dependent upon the width of the wire array. Strong cathode emission is also observed in the SIWA Z-pinch experiments. The amplitude of X-ray plateau before the main pulse in the SIAW experiments is 2 times of that in the standard wire array (SWA) experiments. The duration of the X-ray plateau of the SIAW is longer than that of SAW. The cooler effect due to the single wire plasma expansion in SIAW experiments is much stronger compared with that in SAW experiments. The similar macro magneto hydrodynamics instability structure is observed in both SIAW and SAW experiments.
The effect of surface insulation for the tungsten planar wire arrays was studied on QiangGuang-Ⅰ facility. Utilizing the phenomena analysis, the X-ray radiation of the surface insulated wire arrays (SIWA) is considerably delayed and the delay time is dependent upon the width of the wire array. Strong cathode emission is also observed in the SIWA Z-pinch experiments. The amplitude of X-ray plateau before the main pulse in the SIAW experiments is 2 times of that in the standard wire array (SWA) experiments. The duration of the X-ray plateau of the SIAW is longer than that of SAW. The cooler effect due to the single wire plasma expansion in SIAW experiments is much stronger compared with that in SAW experiments. The similar macro magneto hydrodynamics instability structure is observed in both SIAW and SAW experiments.
2014,
26: 075004.
doi: 10.11884/HPLPB201426.075004
Abstract:
A new xenon flash lamp triggering method is discussed based on trigger and pre-ionization integrally. The pre-ionized lamp is lighted by high voltage trigger circuit, and the current is kept by pulse forming network for 150 s. A trigger power supply is designed for the xenon lamp with a length of 160 mm, a diameter of 9 mm and a gap of 70 mm. The pre-ionized voltage amplitude is 300-900 V, pulse width is 150 s20 s, raising-time is less than 90 s, trigger delay time is less than 90 s, and jitter time is less than 2 s. Experimental results has testified the feasibility of the design theory and method.
A new xenon flash lamp triggering method is discussed based on trigger and pre-ionization integrally. The pre-ionized lamp is lighted by high voltage trigger circuit, and the current is kept by pulse forming network for 150 s. A trigger power supply is designed for the xenon lamp with a length of 160 mm, a diameter of 9 mm and a gap of 70 mm. The pre-ionized voltage amplitude is 300-900 V, pulse width is 150 s20 s, raising-time is less than 90 s, trigger delay time is less than 90 s, and jitter time is less than 2 s. Experimental results has testified the feasibility of the design theory and method.
2014,
26: 075101.
doi: 10.11884/HPLPB201426.075101
Abstract:
The BCM (Bunch Current Measurement) system was developed at BEPCⅡ (Beijing Electron-Positron Collider Ⅱ) for solving the instability. In order to measure the bunch current in accelerator storage rings, the signal of beam position monitor (BPM) was sampled by the high-speed ADC, and the digital signal was processed in field-programmable gate array (FPGA). Based on the reflective memory network, the system realized sharing of the results in high-speed and displayed the results in real-time. The system achieved higher precision, the accuracy of real-time display was 0.1 mA/bucket, and the best measurement resolution reached 10 A/bucket. Since the trigger and the algorithm structure for system were adjusted, the system realized stably work for a long time, the positron and the negative electron storage ring could control the uniformity of the bunch current, which improved the luminance of accelerator collisions.
The BCM (Bunch Current Measurement) system was developed at BEPCⅡ (Beijing Electron-Positron Collider Ⅱ) for solving the instability. In order to measure the bunch current in accelerator storage rings, the signal of beam position monitor (BPM) was sampled by the high-speed ADC, and the digital signal was processed in field-programmable gate array (FPGA). Based on the reflective memory network, the system realized sharing of the results in high-speed and displayed the results in real-time. The system achieved higher precision, the accuracy of real-time display was 0.1 mA/bucket, and the best measurement resolution reached 10 A/bucket. Since the trigger and the algorithm structure for system were adjusted, the system realized stably work for a long time, the positron and the negative electron storage ring could control the uniformity of the bunch current, which improved the luminance of accelerator collisions.
2014,
26: 075102.
doi: 10.11884/HPLPB201426.075102
Abstract:
According to the beam dynamics design, the influence of structure parameters on physical parameters was investigated after modeling the 4-vane RF quadrupole (RFQ) with window and three-dimensional electrodynamics simulations by CST Microwave Studio. We obtained the preliminary structural scheme of the 200 MHz proton 4-vane RFQ with window, the specific shunt impedance of the structure was 79.5 km, frequency separation of two modes was 25.802 MHz. Comparative research of the 4-vane RFQ with window and the traditional 4-vane RFQ shows that the 4-vane RFQ with window provides low operating frequency range, fine electrical stability and relatively high specific shunt impedance.
According to the beam dynamics design, the influence of structure parameters on physical parameters was investigated after modeling the 4-vane RF quadrupole (RFQ) with window and three-dimensional electrodynamics simulations by CST Microwave Studio. We obtained the preliminary structural scheme of the 200 MHz proton 4-vane RFQ with window, the specific shunt impedance of the structure was 79.5 km, frequency separation of two modes was 25.802 MHz. Comparative research of the 4-vane RFQ with window and the traditional 4-vane RFQ shows that the 4-vane RFQ with window provides low operating frequency range, fine electrical stability and relatively high specific shunt impedance.
2014,
26: 079001.
doi: 10.11884/HPLPB201426.079001
Abstract:
The influence of laser remelting on properties of ZrO2-20%Y2O3 thermal barrier coatings deposited by APS method on aluminum substrate, such as the microstructure, phase transition and heat insulation performance is investigated. Pulse laser was used for laser remelting of coating surface. The results show that different specific energy of the laser has an obvious impact on the shaping and performance of the coating. The surface roughness increases and the shaping get worse while the specific energy increases. Under suitable low specific energy laser remelting conditions, the surface and section morphology investigated by SEM indicates that laser remelting can eliminate the layer stacking structure and porosity of coating layer. XRD analysis shows that no phase transition occurred during plasma spraying and laser remelting process. The heat insulation test indicates that the heat insulation performance of APS coatings decreased after laser remelting.
The influence of laser remelting on properties of ZrO2-20%Y2O3 thermal barrier coatings deposited by APS method on aluminum substrate, such as the microstructure, phase transition and heat insulation performance is investigated. Pulse laser was used for laser remelting of coating surface. The results show that different specific energy of the laser has an obvious impact on the shaping and performance of the coating. The surface roughness increases and the shaping get worse while the specific energy increases. Under suitable low specific energy laser remelting conditions, the surface and section morphology investigated by SEM indicates that laser remelting can eliminate the layer stacking structure and porosity of coating layer. XRD analysis shows that no phase transition occurred during plasma spraying and laser remelting process. The heat insulation test indicates that the heat insulation performance of APS coatings decreased after laser remelting.
2014,
26: 079002.
doi: 10.11884/HPLPB201426.079002
Abstract:
The fundamentals and characteristics of pulsed laser truing and dressing technique were illustrated, and the related research process was reviewed and commented from such aspects as optimization of technical parameters and numerical simulation of laser truing and dressing technique for superabrasive grinding wheels. The major problems in the laser truing and dressing technique were pointed out and the development trend was predicted and prospected. Although progress was made and lots of experiences were accumulated in terms of laser truing and dressing technique for superabrasive grinding wheels so far, crucial subjects such as the fundamental science theory, the evaluation system of grinding wheels surface and the precise in-process truing and dressing technique are still very troublesome in this field. Consequently, it requires further exploration and research in the future.
The fundamentals and characteristics of pulsed laser truing and dressing technique were illustrated, and the related research process was reviewed and commented from such aspects as optimization of technical parameters and numerical simulation of laser truing and dressing technique for superabrasive grinding wheels. The major problems in the laser truing and dressing technique were pointed out and the development trend was predicted and prospected. Although progress was made and lots of experiences were accumulated in terms of laser truing and dressing technique for superabrasive grinding wheels so far, crucial subjects such as the fundamental science theory, the evaluation system of grinding wheels surface and the precise in-process truing and dressing technique are still very troublesome in this field. Consequently, it requires further exploration and research in the future.
2014,
26: 079003.
doi: 10.11884/HPLPB201426.079003
Abstract:
According to the characteristics of the laser and its special collimator, we designed a kind of laser projection display system with uniform illumination, using a light pipe as the light homogenization system. The light pipe has several advantages, such as a simple structure, a short period of development, and low cost. The simulation results show that luminous efficiency of the entire illumination system is 78%, and the uniformity is 85%, which reach the designed demands of the optical engine for the laser projection display system.
According to the characteristics of the laser and its special collimator, we designed a kind of laser projection display system with uniform illumination, using a light pipe as the light homogenization system. The light pipe has several advantages, such as a simple structure, a short period of development, and low cost. The simulation results show that luminous efficiency of the entire illumination system is 78%, and the uniformity is 85%, which reach the designed demands of the optical engine for the laser projection display system.
2014,
26: 073221.
doi: 10.11884/HPLPB201426.073221
Abstract:
Hopping-frequency forecasting is one of the key problems in information countermeasure. Based on pseudo-randomness of hopping-frequency and similarity of continuous distribution between these frequency data blocks, a novel method is presented. It applies non-parametric density estimation to predict those sections of frequency with bigger probabilities, which can guide smart comb-like jam of communication. To improve the performance of the method, a scalable computation based on message passing is implemented on multi-node computer system and is verified by the test. Key words: complex electromagnetic environment; hopping-frequency forecasting; on-parametric density estimation; R; message passing; parallel optimization
Hopping-frequency forecasting is one of the key problems in information countermeasure. Based on pseudo-randomness of hopping-frequency and similarity of continuous distribution between these frequency data blocks, a novel method is presented. It applies non-parametric density estimation to predict those sections of frequency with bigger probabilities, which can guide smart comb-like jam of communication. To improve the performance of the method, a scalable computation based on message passing is implemented on multi-node computer system and is verified by the test. Key words: complex electromagnetic environment; hopping-frequency forecasting; on-parametric density estimation; R; message passing; parallel optimization
