Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The ...Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The backlighting images show clearly the processes similar to those occurring in the initial stages of a cylindrical wire-array Z-pinch, including the electric explosion of single wires characterised by the dense wire cores surrounded by a low-density coronal plasma, the expansion of the exploding wire, the sausage instability （m = 0） in the coronal plasma around each wire, the motion of the coronal plasma as well as the wire core toward the current centroid, the formation of the precursor plasma column with a twist structure something like that of higher mode instability, especially the kink instability （m = 1）.展开更多
In order to acquire the most energy-saving luminairedistribution-parameters(LDPs)of highway tunnel interior zone backlighting,the parameters optimization model(POM)of backlighting for tunnel interior zone was establis...In order to acquire the most energy-saving luminairedistribution-parameters(LDPs)of highway tunnel interior zone backlighting,the parameters optimization model(POM)of backlighting for tunnel interior zone was established.Yanlieshan tunnel of Jiujing highway was taken as an example for the optimization.The optimal LDPs of the backlighting system of the tunnel interior zone were obtained by the POM,a comparison between the optimization results and those of Yanlieshan tunnel’s actual lighting system was performed,which showed that the optimized backlighting system with LED lamps installed according to the optimized LDPs could save energy remarkablely even under full capacity lighting condition.Illuminance and illuminance uniformity of the tunnel road surface still met the lighting demands even the LED lamp’s luminance decreased by 30%.A backlighting simulation experiment with the optimized backlighting LDPs for Yanlieshan tunnel was accomplished in the software Dialux.The simulation results basically agreed with the optimization calculated results from the POM which proved the correctness of the backlighting POM.展开更多
An X-pinch axial backlighting system has been designed to quantitatively measure the density distribution of wirearray Z-pinch plasmas. End-on backlighting experiments were carried out on a 200 kA, 100 ns pulsed-power...An X-pinch axial backlighting system has been designed to quantitatively measure the density distribution of wirearray Z-pinch plasmas. End-on backlighting experiments were carried out on a 200 kA, 100 ns pulsed-power generator（PPG-1） at the Tsinghua University. Compared with side-on backlighting, end-on measurements provide an axial view of the evolution of Z-pinch plasmas. Early stages of 2-, 4-, and 8-wire Z-pinch plasmas were observed via point-projection backlighting radiography with a relatively high success rate. The density distribution of Z-pinch plasma on the r–θ plane was obtained directly from the images with the help of step wedges, and the inward radial velocity was calculated. The ablation rates obtained by X-pinch backlighting experiments are compared in detail with those calculated by the rocket model and the results show consistency.展开更多
This study proposes an innovative design method for functional optical film microstructures used in displays and applies this design to LCD backlighting to replace multi-layer optical film functional integration with ...This study proposes an innovative design method for functional optical film microstructures used in displays and applies this design to LCD backlighting to replace multi-layer optical film functional integration with composite optical film. We design a novel optical film microstructure based on light uniformity and wide-angle lumination distribution and determine the optimal optical microstructure parameters by combining the global optimization of a genetic algorithm with ray tracing. The purpose of this study is to develop substitutes for traditional multi-layer prism brightness enhancers and light-diffusing film stacks and to examine the structural changes during calculations and summarize the characteristics. In this study, we focus on determining the optimal light uniformity of new optical film microstructures. The seven-inch LED backlight module of the method proposed in this study achieved 94.59% uniformity and 168° lumination distribution while reducing thickness by 66% to 82% compared to a traditional multi-layer optical film stack.展开更多
The fluid model is proposed to investigate the gas breakdown driven by a short-pulse（such as a Gaussian pulse） highpower microwave at high pressures.However,the fluid model requires specification of the electron ene...The fluid model is proposed to investigate the gas breakdown driven by a short-pulse（such as a Gaussian pulse） highpower microwave at high pressures.However,the fluid model requires specification of the electron energy distribution function（EEDF）;the common assumption of a Maxwellian EEDF can result in the inaccurate breakdown prediction when the electrons are not in equilibrium.We confirm that the influence of the incident pulse shape on the EEDF is tiny at high pressures by using the particle-in-cell Monte Carlo collision（PIC-MCC） model.As a result,the EEDF for a rectangular microwave pulse directly derived from the Boltzmann equation solver Bolsig＋ is introduced into the fluid model for predicting the breakdown threshold of the non-rectangular pulse over a wide range of pressures,and the obtained results are very well matched with those of the PIC-MCC simulations.The time evolution of a non-rectangular pulse breakdown in gas,obtained by the fluid model with the EEDF from Bolsig＋,is presented and analyzed at different pressures.In addition,the effect of the incident pulse shape on the gas breakdown is discussed.展开更多
By analyzing the current distribution of Bow-Tie antenna used in short-pulse ground penetrating radar, the methods of antenna load and driving are presented in this paper to reduce strength of reflective wave both at ...By analyzing the current distribution of Bow-Tie antenna used in short-pulse ground penetrating radar, the methods of antenna load and driving are presented in this paper to reduce strength of reflective wave both at antenna end and excitation point. The numerical simulation results show the strength of reflective wave is smaller than ?55 dB comparing with the driving wave when the methods are adopted. Key words short-pulse GPR - resistive loading - finite difference time domain method CLC number TN 820 Foundation item: Supported by the National Natural Science Foundation of China (49984001)Biography: LI Tai-quan (1961-), male, Ph. D candidate, research direction: antenna model and design展开更多
This study investigated whether the curative effect of short-pulse gastric electrical stimulation （GES） on the vasopressin-induced dyspeptic symptoms was mediated by central opioid peptide-producing neurons. Five fe...This study investigated whether the curative effect of short-pulse gastric electrical stimulation （GES） on the vasopressin-induced dyspeptic symptoms was mediated by central opioid peptide-producing neurons. Five female beagle dogs implanted with 1 pair of electrodes in gastric serosa were used in a two-experiment study. In experiment one, the brain was scanned by positron emission tomography in 3 dogs with and without short-pulse GES, and the radioactivity in nuclei of solitary tract （NST） and hypothalamus was detected. Experiment two was composed of 4 sessions. In session one, the dogs were injected with vasopressin in the absence of short-pulse GES. With session two, the short-pulse GES was simultaneously given via the electrodes with the injection of vasopressin. In sessions three and four, naloxone and naloxone methiodide was administered respectively in the presence of short-pulse GES. Motion sickness-like symptoms were scored and compared among the different sessions. The results showed that the short-pulse GES significantly increased the radioactivity in NST and hypothalamic nuclei （P〈0.05, vs control）. The short-pulse GES could ameliorate the vasopressin-induced motion sickness-like symptoms in dogs. Naloxone, but not naloxone methiodide could attenuate the curative effects of short-pulse GES. It is concluded that NST and hypothalamic nuclei may participate in the mediation of the curative effects of short-pulse GES on dyspepsia-like symptoms. Central opioid peptide-containing neurons presumably mediate the therapeutic effect on dyspeptic symptoms of short-pulse GES.展开更多
The measurements of temperature and moisture content of a wet porous material were accomplished on the micro-seconds scale. The temperature wave was observed when the wet porous material was heated by short-pulsed las...The measurements of temperature and moisture content of a wet porous material were accomplished on the micro-seconds scale. The temperature wave was observed when the wet porous material was heated by short-pulsed laser with high power. It firstly revealed that the moisture content of wet porous material rapidly rises twice in one laser irradiation. The influences of laser parameters, the thickness and initial moisture content of the wet porous material on its temperature and moisture content were investigated.展开更多
A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 wh...A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.展开更多
针对透明物体逆光图像对比度低、可视质量差、部分区域过度曝光、边缘信息模糊等问题,提出了一种改进MSRCR(Multi-Scale Retinex with Color Restoration)的透明物体逆光图像增强算法。首先,在MSRCR算法的基础上添加最小可觉差的倒数作...针对透明物体逆光图像对比度低、可视质量差、部分区域过度曝光、边缘信息模糊等问题,提出了一种改进MSRCR(Multi-Scale Retinex with Color Restoration)的透明物体逆光图像增强算法。首先,在MSRCR算法的基础上添加最小可觉差的倒数作为光照分量的调节因子,解决图像的色偏问题,得到准确清晰的透明物体边缘信息;然后,利用自适应对比度增强算法对原图像进行处理,得到亮度适中,对比度高的图像;最后,将两幅图像按亮度均值比例进行拉普拉斯金字塔融合,并进行线性拉伸。将该算法应用于安瓿瓶视觉尺寸测量,结果表明:改进MSRCR的透明物体逆光图像增强算法,能有效解决MSRCR算法的色偏问题,突显透明物体边缘细节信息,并保留亮度增强效果,将安瓿瓶的尺寸误差由0.35 mm降低到0.1mm,提高了透明物体尺寸测量精度。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 10635050)the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 200748)+2 种基金the International Atomic Energy Agency (Grant No. 14509)the Postdoctoral Science Foundation of China (Grant No. 20090450355)the Special Research Fund for the Doctoral Program of Higher Education,China (Grant No. 200800030037)
文摘Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The backlighting images show clearly the processes similar to those occurring in the initial stages of a cylindrical wire-array Z-pinch, including the electric explosion of single wires characterised by the dense wire cores surrounded by a low-density coronal plasma, the expansion of the exploding wire, the sausage instability （m = 0） in the coronal plasma around each wire, the motion of the coronal plasma as well as the wire core toward the current centroid, the formation of the precursor plasma column with a twist structure something like that of higher mode instability, especially the kink instability （m = 1）.
基金National Natural Science Foundation of China(No.61463015)
文摘In order to acquire the most energy-saving luminairedistribution-parameters(LDPs)of highway tunnel interior zone backlighting,the parameters optimization model(POM)of backlighting for tunnel interior zone was established.Yanlieshan tunnel of Jiujing highway was taken as an example for the optimization.The optimal LDPs of the backlighting system of the tunnel interior zone were obtained by the POM,a comparison between the optimization results and those of Yanlieshan tunnel’s actual lighting system was performed,which showed that the optimized backlighting system with LED lamps installed according to the optimized LDPs could save energy remarkablely even under full capacity lighting condition.Illuminance and illuminance uniformity of the tunnel road surface still met the lighting demands even the LED lamp’s luminance decreased by 30%.A backlighting simulation experiment with the optimized backlighting LDPs for Yanlieshan tunnel was accomplished in the software Dialux.The simulation results basically agreed with the optimization calculated results from the POM which proved the correctness of the backlighting POM.
基金supported by the National Natural Science Foundation of China(Grant Nos.11177086 and 51177086)Guangdong Innovative Research Team Program of China(Grant No.2011S013)+2 种基金the National Key Research and Develop Program of China(Grant No.2016YFC0105102)the National Basic Research Program of China(Grant Nos.2012AA02A604 and 2015AA043203)Beijing Center for Mathematics and Information Interdisciplinary Sciences,China
文摘An X-pinch axial backlighting system has been designed to quantitatively measure the density distribution of wirearray Z-pinch plasmas. End-on backlighting experiments were carried out on a 200 kA, 100 ns pulsed-power generator（PPG-1） at the Tsinghua University. Compared with side-on backlighting, end-on measurements provide an axial view of the evolution of Z-pinch plasmas. Early stages of 2-, 4-, and 8-wire Z-pinch plasmas were observed via point-projection backlighting radiography with a relatively high success rate. The density distribution of Z-pinch plasma on the r–θ plane was obtained directly from the images with the help of step wedges, and the inward radial velocity was calculated. The ablation rates obtained by X-pinch backlighting experiments are compared in detail with those calculated by the rocket model and the results show consistency.
文摘This study proposes an innovative design method for functional optical film microstructures used in displays and applies this design to LCD backlighting to replace multi-layer optical film functional integration with composite optical film. We design a novel optical film microstructure based on light uniformity and wide-angle lumination distribution and determine the optimal optical microstructure parameters by combining the global optimization of a genetic algorithm with ray tracing. The purpose of this study is to develop substitutes for traditional multi-layer prism brightness enhancers and light-diffusing film stacks and to examine the structural changes during calculations and summarize the characteristics. In this study, we focus on determining the optimal light uniformity of new optical film microstructures. The seven-inch LED backlight module of the method proposed in this study achieved 94.59% uniformity and 168° lumination distribution while reducing thickness by 66% to 82% compared to a traditional multi-layer optical film stack.
基金supported by the National Basic Research Program of China(Grant No.2013CB328904)the NSAF of China(Grant No.U1330109)2012 Doctoral Innovation Funds of Southwest Jiaotong University
文摘The fluid model is proposed to investigate the gas breakdown driven by a short-pulse（such as a Gaussian pulse） highpower microwave at high pressures.However,the fluid model requires specification of the electron energy distribution function（EEDF）;the common assumption of a Maxwellian EEDF can result in the inaccurate breakdown prediction when the electrons are not in equilibrium.We confirm that the influence of the incident pulse shape on the EEDF is tiny at high pressures by using the particle-in-cell Monte Carlo collision（PIC-MCC） model.As a result,the EEDF for a rectangular microwave pulse directly derived from the Boltzmann equation solver Bolsig＋ is introduced into the fluid model for predicting the breakdown threshold of the non-rectangular pulse over a wide range of pressures,and the obtained results are very well matched with those of the PIC-MCC simulations.The time evolution of a non-rectangular pulse breakdown in gas,obtained by the fluid model with the EEDF from Bolsig＋,is presented and analyzed at different pressures.In addition,the effect of the incident pulse shape on the gas breakdown is discussed.
文摘By analyzing the current distribution of Bow-Tie antenna used in short-pulse ground penetrating radar, the methods of antenna load and driving are presented in this paper to reduce strength of reflective wave both at antenna end and excitation point. The numerical simulation results show the strength of reflective wave is smaller than ?55 dB comparing with the driving wave when the methods are adopted. Key words short-pulse GPR - resistive loading - finite difference time domain method CLC number TN 820 Foundation item: Supported by the National Natural Science Foundation of China (49984001)Biography: LI Tai-quan (1961-), male, Ph. D candidate, research direction: antenna model and design
基金supported by a grant from the National Natural Sciences Foundation of China (No 30500233)
文摘This study investigated whether the curative effect of short-pulse gastric electrical stimulation （GES） on the vasopressin-induced dyspeptic symptoms was mediated by central opioid peptide-producing neurons. Five female beagle dogs implanted with 1 pair of electrodes in gastric serosa were used in a two-experiment study. In experiment one, the brain was scanned by positron emission tomography in 3 dogs with and without short-pulse GES, and the radioactivity in nuclei of solitary tract （NST） and hypothalamus was detected. Experiment two was composed of 4 sessions. In session one, the dogs were injected with vasopressin in the absence of short-pulse GES. With session two, the short-pulse GES was simultaneously given via the electrodes with the injection of vasopressin. In sessions three and four, naloxone and naloxone methiodide was administered respectively in the presence of short-pulse GES. Motion sickness-like symptoms were scored and compared among the different sessions. The results showed that the short-pulse GES significantly increased the radioactivity in NST and hypothalamic nuclei （P〈0.05, vs control）. The short-pulse GES could ameliorate the vasopressin-induced motion sickness-like symptoms in dogs. Naloxone, but not naloxone methiodide could attenuate the curative effects of short-pulse GES. It is concluded that NST and hypothalamic nuclei may participate in the mediation of the curative effects of short-pulse GES on dyspepsia-like symptoms. Central opioid peptide-containing neurons presumably mediate the therapeutic effect on dyspeptic symptoms of short-pulse GES.
基金This work was financially supported the National Natural Science Foundation of China (No.50376063) and the Chinese NationalKey Foundation Research Subject (No.G2000026306)
文摘The measurements of temperature and moisture content of a wet porous material were accomplished on the micro-seconds scale. The temperature wave was observed when the wet porous material was heated by short-pulsed laser with high power. It firstly revealed that the moisture content of wet porous material rapidly rises twice in one laser irradiation. The influences of laser parameters, the thickness and initial moisture content of the wet porous material on its temperature and moisture content were investigated.
基金The National Basic Research Program of China(973 Program)(No.2013CB328803)the National Natural Science Foundation of China(No.51002031)+1 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No.20100092120022)the National High Technology Research and Development Program of China(863 Program)(No.2012AA03A302,2013AA011004)
文摘A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.
文摘针对透明物体逆光图像对比度低、可视质量差、部分区域过度曝光、边缘信息模糊等问题,提出了一种改进MSRCR(Multi-Scale Retinex with Color Restoration)的透明物体逆光图像增强算法。首先,在MSRCR算法的基础上添加最小可觉差的倒数作为光照分量的调节因子,解决图像的色偏问题,得到准确清晰的透明物体边缘信息;然后,利用自适应对比度增强算法对原图像进行处理,得到亮度适中,对比度高的图像;最后,将两幅图像按亮度均值比例进行拉普拉斯金字塔融合,并进行线性拉伸。将该算法应用于安瓿瓶视觉尺寸测量,结果表明:改进MSRCR的透明物体逆光图像增强算法,能有效解决MSRCR算法的色偏问题,突显透明物体边缘细节信息,并保留亮度增强效果,将安瓿瓶的尺寸误差由0.35 mm降低到0.1mm,提高了透明物体尺寸测量精度。
