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Modeling and simulation of pinhole channels

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The Journal of China Universities of Posts and Telecommunications 2010年第2期17卷 67-71页

作者： WEI Ming-dong ZHANG Yun-feng ZHANG Ye-rong PAN Zi-yi School of Eleca:onic Science and Engineering Nanjing University of Posts and Teleenmmtmications Nanjing 210003 China Jiangsu Posts and Telecommunications Planning and Designing Institute Co. Ltd Nanjing 210006 China

This article presents a general pinhole channel reference model based on the cause of pinhole effect. On the base of this reference model, a deterministic simulation model is developed by keeping the difference of correlation properties between reference and simulation model as smaller as possible. The correlation properties include temporal autocorrelation fimction （ACF）, two-dimensional （2-D） space cross-correlation function （CCF） and frequency correlation function （FCF）. The results show that although pinhole channel has good correlation properties, the channel capacity is very low because of the low rank of channel transform matrix.

关键词： pinhole channel modeling channel simulation deterministic simulation models

Spot size measurement of a flash-radiography source using the pinhole imaging method

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Chinese Physics C 2016年第7期40卷 124-128页

作者：王毅李勤陈楠程晋明谢宇彤刘云龙龙全红 Key Laboratory of Pulsed Power Institute of Fluid Physics China Academy of Engineering Physics

The spot size of the X-ray source is a key parameter of a flash-radiography facility, and is usually quoted as an evaluation of the resolving power. The pinhole imaging technique is applied to measure the spot size of the Dragon-I linear induction accelerator, by which a two-dimensional spatial distribution of the source spot is obtained. Experimental measurements are performed to measure the spot image when the transportation and focusing of the electron beam are tuned by adjusting the currents of solenoids in the downstream section. The spot size of full-width at half maximum and that defined from the spatial frequency at half peak value of the modulation transfer function are calculated and discussed.

关键词： spot size X-ray source pinhole linear induction accelerator

Performance Evaluation of the Thick pinhole Gamma Rays Diagnostic System

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Journal of Analytical Sciences, Methods and Instrumentation 2018年第3期8卷 25-36页

作者： Hongwei Xie Jinchuan Chen Linbo Li Qiang Yi Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang China

The diagnostic methods for the profile of the radiation source were estab-lished at first based on the pinhole imaging principle. In this paper, the relationships among various parameters of the gamma-rays crammer such as the modulation transfer function (MTF), the noise power spectrum (NPS), the signal-noise ratio (SNR) and the detective quantum efficiency (DQE) are developed and studied experimentally on the cobalt radiation source. The image diagnostic system is consisting with rays-fluorescence convertor (YAG crystal), optical imaging system, MCP image intensifier, CCD camera and other devices. The spatial resolution of the modulation transfer function (MTF) at 10% intensity was measured as 1 lp/mm by knife-edge method. The quantum of the measurement system is about 150 under weak radiation condition due to the single particle detection efficiency of the system. The dynamic range was inferred preliminarily as about 437. The required radiation intensity was calculated using the experiment result for the (SNR) = 1, 5, 10, respectively. The theoretical investigation results show that the radiation image with (SNR) = 1 can be only obtained when the pinhole diameter is 0.7 mm, object distance and image distance are both 200 cm, and the radiation intensity is about 1.0 × 1012 Sr-1·cm-2.

关键词： Gamma-Ray Camera pinhole YAG MCP Image Intensifier CCD MTF NNPS

Study of Supper Resolution Processing Methods for Thick pinhole Image

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维普期刊数据库

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Journal of Signal and Information Processing 2013年第2期4卷 222-227页

作者： Hongwei Xie Faqiang Zhang Jianhua Zhang Zeping Xu Linbo Li Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang Mianyang China

An image super resolution reconstruction method was used to improve the spatial resolution of the thick pinhole imaging system and to mitigate the limitations of the image spatial resolution of the hardware of the image diagnostic system. The thick pinhole is usually applied into the diagnostics of the high energy neutron radiation image. Due to the impacts among its energy flux, spatial resolution and effective field of view, in dealing with the large area radiation source, the spatial resolution of the thick pinhole neutron image cannot meet the requirements for high precision modeling of the radiation source image. In this paper, the Lucy-Richardson image super resolution reconstruction method was used to simulate the thick pinhole imaging and super resolution image reconstruction. And the spatial resolution of the image could be increased by over three times after the image super resolution reconstruction. Besides, in dealing with the pseudo-noise, plum blossom shape appeared in the image super resolution reconstruction. The analysis of the source of the pseudo-noise was made based on the simulation of the image reconstruction under various conditions according to the characteristics of the thick pinhole image configuration.

关键词： Space-Variant Point Spread Function Thick pinhole Image Super-Resolution Lucy-Richardson

Novel mechanism for boring non-cylinder piston pinhole based on giant magnetostrictive materials

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Journal of Shanghai University(English Edition) 2008年第4期12卷 363-367页

作者：翟鹏张承瑞王新亮秦磊秦有志 School of Mechanical Engineering Shandong University Weihai 264209 P. R. China Shandong Binzhou Bohai Piston Co. Ltd. Binzhou 256602 P. R. China

To bear more loads for heavy truck pistons, the shape of heavy truck piston pinhole is often designed as noncylinder form. Current methods cannot meet the needs for precision machining on non-cylinder piston pinhole （NCPPH）. A novel mechanism based on giant magnetostrictive materials （GMM） is presented. New models are established for the servo mechanism, GMM, and magnetizing force of the control solenoid to characterize the relationship between the control current of the solenoid and the displacement of the giant magnetostrictive actuator （GMA）. Experiments show that the novel mechanism can meet the needs to perform fine machining on NCPPH effectively.

关键词： giant magnetostrictive materials (GMM) piston pinhole boring

Microperforate (pinhole) hymen and infertility;a rare case report

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Open Journal of Obstetrics and Gynecology 2012年第3期2卷 287-288页

作者： Davut Güven Kadir Bakay Serkan Kuruoglu Department of Obstetrics and Gynecology 19 Mayis University School of Medicine Samsun Turkey Private Hospital Department of Obstetrics and Gynecology Turkey

Inroduction Female genital tract anomalies may have a devastating impact on the potential for sexual activity and fertility. Microperforate (pinhole) hymen is one of them. Microperforate hymen can lead to infertility, primary amenorrhea, acute or chronic pelvic pain, abnormal vaginal bleeding, dysuria, pollakiuria or a foul-smelling vaginal discharge. Aim We aim to report a patient who had intercourse problems and infertility complaints later found to have a microper-forate hymen. Discussion pinhole opening of hymen may permit passage of fluids. Consequently spontaneous pregnancy can occur rarely. A few reports showed pregnancies with intact hymen without penetration of penis. But in general patients have fertility problems. Conclusion The results of the surgery are similar in all techniques and the particular surgical centre will have its own preference of which technique it prefers since after diagnosis definitive treatment is surgical and effective. Failure to manage these patients correctly may have long-term sequelae for their psychological, sexual and reproductive health.

关键词： Hymen pinhole Microperforate Infertility

Drainage design combining drain holes and pinholes for tunnel boring machine segments subject to high water pressure

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Frontiers of Structural and Civil Engineering 2023年第11期17卷 1723-1738页

作者： Yao LU Ming HUANG Zhijie CHEN Zisheng ZENG Yuchuan LIU Guangzhao DU College of Civil Engineering Fuzhou UniversityFuzhou 350108China Urban Rail Branch China Railway 11th Bureau Group Co.Ltd.Wuhan 430071China

Balance of the groundwater and ecology is crucial for controlled ***,regarding the segments of tunnel boring machines(TBMs)under high water pressure,the stability of the lining structure is often reduced by excessive drain holes required to achieve this *** large discharge of pinholes can easily have severe consequences,such as the lowering of the groundwater table,drying of springs,and vegetation ***,in this study,according to the fluid-structure coupling theory,a new drainage design for TBM segments was developed by considering a mountain tunnel subject to a high water pressure as a case *** evolution characteristics,including the external water pressure of the lining,discharge volume of the segment,and groundwater-table drawdown,were investigated via numerical modeling with drain holes and *** results indicated that the optimal design parameters of drainage segments for the project case were as follows:a circumferential spacing angle and longitudinal number on one side of a single ring of 51°and 2,respectively,for the drain holes and an inclination angle and length of 46.41°and 0.25 times the grouting thickness,respectively,for the pin holes.

关键词： TBM segment high water pressure drain hole pinhole groundwater table drawdown

Experimental comparison of various techniques for spot size measurement of high-energy X-ray sources

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Chinese Physics C 2016年第8期40卷 136-141页

作者：王毅李勤陈楠程晋明李成刚李洪龙全红石金水邓建军 Key Laboratory of Pulsed Power Institute of Fluid PhysicsChina Academy of Engineering Physics

In flash-radiography experiments, the quality of the acquired image strongly depends on the focal size of the X-ray source spot. A variety of techniques based on imaging of the pinhole, the slit and the rollbar are adopted to measure the focal spot size of the Dragon-I linear induction accelerator. The image of the pinhole provides a two-dimensional distribution of the X-ray spot, while those of the slit and the rollbar give a line-spread distribution and an edge-spread distribution, respectively. The spot size characterized by the full-width at half-maximum and that characterized by the LANL definition are calculated for comparison.

关键词： linear induction accelerator spot size pinhole slit rollbar

Alternative Interpretation of Speckle Autocorrelation Imaging Through Scattering Media

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Photonic Sensors 2022年第3期12卷 79-87页

作者： Honglin LIU Puxiang LAI Jingjing GAO Zhentao LIU Jianhong SHI Shensheng HAN Key Laboratory for Quantum Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Department of Biomedical Engineering The Hong Kong Polytechnic UniversityHong KongChina Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518000China State Key Laboratory of Advanced Optical Communication Systems and Networks and Center of Quantum Sensing and Information Processing(QSIP) Shanghai Jiao Tong UniversityShanghai 200240China Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China

High-resolution optical imaging through or within thick scattering media is a long sought after yet unreached *** the past decade,the thriving technique developments in wavefront measurement and manipulation do not significantly push the boundary *** optical diffusion limit is still a *** this work,we propose that a scattering medium can be conceptualized as an assembly of randomly packed pinhole cameras and the corresponding speckle pattern as a superposition of randomly shifted pinhole *** concept is demonstrated through both simulation and experiments,confirming the new perspective to interpret the mechanism of information transmission through scattering media under incoherent *** also analyze the efficiency of single-pinhole and dual-pinhole *** in infancy,the proposed method reveals a new perspective to understand imaging and information transmission through scattering media.

关键词： Imaging scattering media pinhole information channel autocorrelation transport mean free path random phasemask