Aberration compensation of laser mode unging a novel intra-cavity adaptive optical system
作者：
Li, Jie* ;Chen, Xiqu
期刊：
Optik ,2013年124(3):272-275 ISSN：0030-4026
通讯作者：
Li, Jie
作者机构：
[Li, Jie] Wuhan Polytech Univ, Dept Elect & Informat Engn, Wuhan, Peoples R China.;[Chen, Xiqu] Wuhan Polytech Univ, Dept Math & Phys, Wuhan, Peoples R China.
通讯机构：
[Li, Jie] W;Wuhan Polytech Univ, Dept Elect & Informat Engn, Wuhan, Peoples R China.
关键词：
Aberration compensation;Adaptive optical systems;Closed loops;Control voltages;Deformable mirrors;Distortion effects;Dynamic aberrations;Intracavities;MEMS deformable mirror;Micro mirror;Output power;Thermally induced;Wavefront aberrations;Aberrations;Adaptive optics;Automation;Control;Laser beams;MEMS;Mirrors;Solid state lasers;Optical systems
摘要：
Thermally induced optically distortion effects are one of the main impediments to be overcome in developing high power solid-state lasers. To compensate the dynamic aberration of laser beam, an intra-cavity adaptive optical system was developed. A beaconing light was introduced to measure the wavefront aberration of intracavity laser beam and a MEMS deformable mirror was used to improve the wavefront aberration and output power of the laser. A genetic algorithm was used to adjust the control voltages of 37 independent electrodes to vary the shape of the deformable mirror surface such that the aberration of laser beam can be compensated. The experimental result showed that the output power was increased nearly 3 times and the beam quality was improved obviously by closed loop automatic control of the adaptive optical system. © 2011 Elsevier GmbH.
语种：
英文
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Optimal Capacity Allocation Between Primary and Secondary Services
作者：
Chen Xia*
作者机构：
[Chen Xia; Chen, X] Wuhan Polytech Univ, Sch Math & Comp Sci, Wuhan 430022, Peoples R China.
会议名称：
International Conference on Intelligence Science and Information Engineering (ISIE 2012)
会议时间：
AUG 25-26, 2012
会议地点：
Lushan, PEOPLES R CHINA
会议主办单位：
Wuhan Polytech Univ, Sch Math & Comp Sci, Wuhan 430022, Peoples R China.
会议论文集名称：
Advances in Intelligent Systems Research
关键词：
Queueing System;Optimal Control;Primary Service;Secondary Service
摘要：
In this research, we study an M/M/1 queueing system with both a primary service and a secondary service that share a common server's capacity. We show that such system's optimal control policy is that the capacity allocated for the secondary service is monotonically non-increasing in the number of people in the system. Also, the possible optimal secondary capacity is actually on the convex envelope of the secondary cost function.
语种：
英文
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Theoretical Investigation of ZnSe epitaxy growth on GaAs(001) Substrate
作者：
Chen Liangyan* ;Chen Xiqu;Zhang Daoli
期刊：
Applied Mechanics and Materials ,2012年130-134:860-863 ISSN：1660-9336
通讯作者：
Chen Liangyan
作者机构：
[Chen Liangyan; Chen Xiqu] Whan Polytech Univ, Dept Math & Phys, Wuhan, Hubei, Peoples R China.;[Zhang Daoli] Huazhong Univ Sci & Technol, Dept elect sci & technol, Wuhan, Hubei, Peoples R China.
通讯机构：
[Chen Liangyan] W;Whan Polytech Univ, Dept Math & Phys, Wuhan, Hubei, Peoples R China.
会议名称：
2011 3rd International Conference on Mechanical and Electronics Engineering, ICMEE 2011
会议时间：
23 September 2011 through 25 September 2011
会议地点：
Hefei, PEOPLES R CHINA
会议主办单位：
[Chen Liangyan;Chen Xiqu] Whan Polytech Univ, Dept Math & Phys, Wuhan, Hubei, Peoples R China.^[Zhang Daoli] Huazhong Univ Sci & Technol, Dept elect sci & technol, Wuhan, Hubei, Peoples R China.
会议论文集名称：
Applied Mechanics and Materials
关键词：
epitaxy growth;binding energy;counterweight;absorption
摘要：
Theoretical studies of ZnSe epitaxy growth on GaA (001) surface were performed with first principle calculation, the bonding energy of absorbing monolayer atoms, charge and binding properties of the interface atoms were investigated to account for the growth of ZnSe films on different GaAs(001) surface. And it's concluded that As-terminated stable AsGa(001) substrate placed in Zn atmosphere, with absorption of Zn atoms on AsGa(001) substrate, which can be a counterweight to form a neutral GaAs/ZnSe interface, may be helpful in reducing the defects of the ZnSe epitaxy growth on GaAs(001) substrate. ©(2012) Trans Tech Publications, Switzerland.
语种：
英文
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Pattern Search for Generalized Hyperbolic Distribution and Financial Risk Measure
作者：
Chen, Xiufang* ;Chen, Gaobo
期刊：
Applied Mechanics and Materials ,2012年155-156:424-429 ISSN：1660-9336
通讯作者：
Chen, Xiufang
作者机构：
[Chen, Xiufang] Wuhan Polytech Univ, Coll Elect & Elect Engn, Wuhan, Peoples R China.;[Chen, Gaobo] Wuhan Polytech Univ, Coll Math & Comp Sci, Wuhan, Peoples R China.
通讯机构：
[Chen, Xiufang] W;Wuhan Polytech Univ, Coll Elect & Elect Engn, Wuhan, Peoples R China.
会议地点：
Hunan Inst Engn, Chongqing, PEOPLES R CHINA
会议主办单位：
Hunan Inst Engn
会议论文集名称：
Applied Mechanics and Materials
关键词：
Generalized hyperbolic distribution;Monte carlo;Pattern search;Risk measure
摘要：
A new parameter estimation-pattern search algorithm based on maximum likelihood estimation is used to estimate the parameters of generalized hyperbolic distribution, normal inverse Gaussian distribution and hyperbolic distribution, which are used to fit the log-return of Shanghai composite index. The goodness of fit is tested based on Anderson & Darling distance and FOF distance who pay more attention to tail distances of some distribution. Monte Carlo simulation are used to determin the critical values of Anderson & Darling distance and FOF distance of different distributions. Value at risk (VaR) and conditional value at risk (CVaR) are estimated for the fitted generalized hyperbolic distribution, normal inverse Gaussian distribution and hyperbolic distributio. The results show that generalized hyperbolic distribution family is more suitable for risk measure such as VaR and CVaR than normal distribution.
语种：
英文
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Responsivity analysis of micro-bolometer under pulsed bias
作者：
Chen, Xiqu* ;Lv, Qiang;Yi, Xinjian
期刊：
Optik ,2011年122(23):2143-2146 ISSN：0030-4026
通讯作者：
Chen, Xiqu
作者机构：
[Lv, Qiang; Chen, Xiqu] Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Hubei, Peoples R China.;[Yi, Xinjian] Huazhong Univ Sci & Technol, Dept Optoelect Engn, Wuhan 430074, Hubei, Peoples R China.;[Yi, Xinjian] Wuhan Natl Lab Optoelect, Wuhan 430074, Peoples R China.
通讯机构：
[Chen, Xiqu] W;Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Hubei, Peoples R China.
关键词：
Integration time;Key factors;Microbolometer;Numerical calculation;Output signal;Pulsed bias;Pulsed voltages;Responsivity;Signal to noise;Thermal model;Voltage bias;Bias voltage;Focusing;Infrared detectors;Signal to noise ratio;Thermography (temperature measurement);Bolometers
摘要：
The physical thermal model for micro-bolometer under pulsed voltage bias is built, and the current responsivity expression of the micro-bolometer based on this physical thermal model is approximatively obtained in theory, which is in accordance with the numerical calculation of micro-bolometer current responsivity. Theoretical analysis shows that the current responsivity parameter is changed with voltage bias time, and this indicates that the current responsivity of micro-bolometer under pulsed voltage bias can be controlled by adjusting useful voltage bias time which is equal to micro-bolometer current integration time. The expression of the current responsivity parameter reveals key factors relevant to the output signal signal-to-noise of micro-bolometric focal plane array, and theoretically gives one of the directions to increase the output signal signal-to-noise of micro-bolometric focal plane array. © 2011 Elsevier GmbH. All rights reserved.
语种：
英文
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Theoretical analysis and experimental application of CDS CMOS integrated circuit for uncooled infrared focal plane arrays
作者：
Chen, Xiqu*
期刊：
Optik ,2011年122(9):792-795 ISSN：0030-4026
通讯作者：
Chen, Xiqu
作者机构：
[Chen, Xiqu] Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Peoples R China.
通讯机构：
[Chen, Xiqu] W;Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Peoples R China.
关键词：
CdS;CMOS;Complementary metal oxide semiconductors;Correlated double sampling;Eliminating noise;Experimental application;High noise;Key factors;Low-Frequency Noise;Noise frequencies;Noise source;Readout chips;Readout integrated circuits;Sampling time;Uncooled;Uncooled infrared focal plane array;Uncooled infrared focal plane arrays;Uncooled IRFPA;CMOS integrated circuits;Focal plane arrays;Focusing;Infrared detectors;Integrated circuits;Integration;Lumped parameter networks;Metallic compounds;MOS devices;Readout systems;Electric network analysis
摘要：
In this paper, a typical correlated double sampling (CDS) complementary metal oxide semiconductor (CMOS) circuit for uncooled infrared focal plane array (IRFPA) is theoretically analyzed, the key factor of CDS CMOS integrated circuit is pointed out, and a new CDS integrated circuit which is high correlative for low-frequency noise is applied in an experimental readout chip for uncooled IRFPA. Theoretical analysis indicates that the sample transfer function of a noise source acted on by CDS processing is related to noise frequency and sampling time interval and the key factor of CDS circuit for reducing or eliminating noise in readout integrated circuit is the sampling time interval. The experimental readout chip with high noise-correlative CDS integrated circuit is fabricated to verify the theoretical analysis, which can be applied to uncooled IRFPAs. © 2010 Elsevier GmbH. All rights reserved.
语种：
英文
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Optical switch with low-phase transition temperature based on thin nanocrystalline VOx film
作者：
Chen, Xiqu* ;Dai, Jun
期刊：
Optik ,2010年121(16):1529-1533 ISSN：0030-4026
通讯作者：
Chen, Xiqu
作者机构：
[Chen, Xiqu] Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Hubei, Peoples R China.;[Dai, Jun] Huazhong Univ Sci & Technol, Dept Optoelect Engn, Wuhan 430074, Hubei, Peoples R China.;[Dai, Jun] Wuhan Natl Lab Optoelect, Wuhan 430074, Peoples R China.
通讯机构：
[Chen, Xiqu] W;Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Hubei, Peoples R China.
关键词：
Au electrodes;Conducting phase;Electrode layers;Extinction ratios;Metallic phase;Micromachining technologies;Nanocrystalline;Nanocrystalline vanadium oxide;Nanocrystallines;Phase transition temperature;Phase transition temperatures;Power dissipation;Silicon substrates;Switching power supplies;Switching response;Testing results;Vanadium dioxide;Electric power supplies to apparatus;Gold;Nanocrystalline powders;Optical communication;Optical switches;Phase transitions;Power electronics;Superconducting transition temperature;Time switches;Vanadium;Vanadium alloys;Vanadium compounds;Optical films
摘要：
An optical switch is fabricated by using micromachining technology, which is based on thin nanocrystalline vanadium oxide (VO<inf>x</inf>) film, and it consists of four layers: a silicon (Si) substrate layer, a VO<inf>x</inf>layer, a Si<inf>3</inf>N<inf>4</inf>buffer layer, and an aurum (Au) electrode layer. By applying a switching power supply to a pair of the Au electrodes, the optical switch is controlled to exhibit from an "on" state with semi-conducting phase to an "off" state with metallic phase. The optical switch performance is investigated, and testing results show that its extinction ratio is about 14 dB, its switching response time can achieve about 1.5 ms, and the power dissipation required for stimulating switching to work can be below about 15 mW at least, which is lower than the power dissipation of conventional optical switches based on microstructure thin vanadium dioxide (VO<inf>2</inf>) films. This kind of optical switch is potential to be applied as optical switch for optical communication. ©2010 Published by Elsevier GmbH. All rights reserved.
语种：
英文
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Phase-shift interferometry combined with surface plasmon resonance effect for two-dimensional bio-surface analysis
作者：
Chen, Xiqu* ;Lv, Qiang
期刊：
Optik ,2010年121(9):818-820 ISSN：0030-4026
通讯作者：
Chen, Xiqu
作者机构：
[Chen, Xiqu] Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Hubei, Peoples R China.;[Lv, Qiang] Huazhong Univ Sci & Technol, Dept Optoelect Engn, Wuhan 430074, Hubei, Peoples R China.;[Lv, Qiang] Natl Lab Photoelect, Wuhan 430074, Peoples R China.
通讯机构：
[Chen, Xiqu] W;Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Hubei, Peoples R China.
关键词：
Imaging sensors;Novel techniques;Optical intensities;Phase shift interferometry;Reflected light;Spatial phase variation;Spatial sensitivity;Surface plasmons;Interferometers;Interferometry;Optoelectronic devices;Phase shift;Plasmons;Surface analysis;Two dimensional;Surface plasmon resonance
摘要：
The phase-shift interferometry combined with surface plasmon resonance (SPR) effect has been studied as a novel technique used to analyze the bio-surface, which measures the spatial phase variation of SPR reflected light. The spatial sensitivity of the SPR imaging sensor is improved over the conventional SPR imaging systems based on optical intensity. Crown Copyright © 2009.
语种：
英文
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Optimal Control of Auxiliary Service Queueing System
作者：
Chen, Xia* ;Wang, Chen
期刊：
THIRD INTERNATIONAL CONFERENCE ON GENETIC AND EVOLUTIONARY COMPUTING ,2009年:773-776
通讯作者：
Chen, Xia
作者机构：
[Chen, Xia] Wuhan Polytech Univ, Dept Comp Sci, Wuhan, Peoples R China.;[Wang, Chen] Univ British Columbia, Dept Mkt, Vancouver, BC, Canada.
通讯机构：
[Chen, Xia] W;Wuhan Polytech Univ, Dept Comp Sci, Wuhan, Peoples R China.
会议名称：
2009 Third International Conference on Genetic and Evolutionary Computing, WGEC 2009, Guilin, China, 14-17 October 2009
关键词：
Queueing System;Auxiliary Service;Dynamic Programming;Uniformization
摘要：
We consider an M/M/1 queueing system with auxiliary service in addition to primary service. When the auxiliary service is requested, the server allocates part of its capacity to process the additional service. We show that the possible optimal auxiliary capacity is actually on the convex envelope of the auxiliary cost function. Also, the optimal control policy is that the allocated capacity for auxiliary service is monotonically non-increasing in the number of people in the system.
语种：
英文
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Design and experimental verification of a readout integrated circuit for uncooled focal plane arrays
作者：
Chen, Xiqu*
期刊：
Optical Engineering ,2008年47(10):104402 ISSN：0091-3286
通讯作者：
Chen, Xiqu
作者机构：
[Chen, Xiqu] Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Peoples R China.
通讯机构：
[Chen, Xiqu] W;Wuhan Polytech Univ, Dept Math & Phys, Wuhan 430023, Peoples R China.
关键词：
CMOS integrated circuits;Dielectric devices;Direct injection;Feedback amplifiers;Focal plane arrays;Focusing;Integrated circuit design;Integrated circuits;Metallic compounds;Metals;MOS devices;Operational amplifiers;Oxide semiconductors;Readout systems;Timing circuits;Transistors;Complementary metal oxide semiconductors;Correlated double sampling;Experimental verification;Integration circuits;Low-power dissipation;Readout integrated circuits;Speed performance;Uncooled focal plane array;Low power electronics
摘要：
A complementary metal oxide semiconductor (CMOS) readout integrated circuit (ROIC) for an uncooled focal plane array (UFPA) is presented. The circuit consists of four major parts: a bolometer current direct injection (BCDI) input circuit, a column-shared capacitor feedback transimpedance amplifier (CTIA) integration circuit, a column-shared correlated double sampling (CDS) circuit, and a common output circuit. By applying the BCDI input circuit and the column-shared integration circuit of CTIA structure, high performance (high gain, a highly stable detector bias, and high photon current injection efficiency) is realized with a small pixel size. Moreover, the CDS circuit is utilized to reduce or eliminate noise of the readout circuit, and the common output circuit is utilized to improve the speed performance of the ROIC under low power dissipation. An experimental readout chip for a 45-μm-pitch 64 x 64 element VO2-based UFPA has been designed and fabricated. The measurement results of the fabricated readout chip at 298 K with 5-V supply voltage have successfully verified the readout function and the performance improvement. The proposed CMOS ROIC can be applied to a micro bolometric UFPA. © 2008 Society of Photo-Optical Instrumentation Engineers.
语种：
英文
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