中国科学院机构知识库网格系统: 检索

Eight-neighborhood based background modeling (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Materials Science and Information Technology, MSIT 2012, August 24, 2012 - August 26, 2012, Xi'an, Shaan, China
Yan L.; Ming D.; Lei J.

收藏 | 浏览/下载：10/0 | 提交时间：2013/03/25

In order to solve the Gaussian kernel density-based background modeling we propose a background modeling method based on an 8-neighborhood pixels sample set. In this method we use the target pixel and its surrounding 8-neighborhood pixels to analyze whether it is included in the background or in the foreground sample space. Experimental results show that the method can judge the object as the background interference caused by the cyclical movement. By practical verification the algorithm of the background modeling can full meet the requirements of the target detection algorithm. (2012) Trans Tech Publications Switzerland.

Study on the difference between turfy soil and normal peat soil in China (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Vibration, Structural Engineering and Measurement, ICVSEM2011, October 21, 2011 - October 23, 2011, Shanghai, China
作者: Nie L.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

As the special soil turfy soil and peat soil in China contained some similar properties with high void ratio high water content high organic content etc. But turfy soil also had properties which difference from peat soil. In this paper based on the formation of the cause and geological environment and geomorphologic characteristics of geological in the quaternary took the typical and widespread turfy soil and peat soil regions for example systematically discussed the material composition and macroscopic and microcosmic structural features put further research on the physical chemistry mechanical characteristics. Then the come to the conclusion that the essential reason for difference between turfy soil and peat soil were decomposition degree and organic content. The result that worse engineering properties such as higher the moisture content porosity compressibility internal cohesion and the lower specific weight consolidation coefficient and permeability were due to the lower decomposition degree and higher organic content of turfy soil than peat soil. It can provide reference to the practical projects of turfy soil to distinguish peat soil according to this characteristic. (2012) Trans Tech Publications.

The flow field analysis of the automotive power streering congtrol unit's flow channel (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Advanced Design and Manufacturing Engineering, ADME 2011, September 16, 2011 - September 18, 2011, Guangzhou, China
Cheng K.; Yan L.; Li G.; Tang J.

收藏 | 浏览/下载：13/0 | 提交时间：2013/03/25

The automotive power steering units must be taken performance test after they are integrated assembly and then left the factory if it is qualified.Because its internal flow channel is very complicated and the residual hydraulic oil can not be eleminated clearly.So we can set up a 3D model flow channel based on CATIA and use FLUENT software to analysis the key flow channel analysing it's pressure distribution and velocity vector diagram then get the real reasonable resluts which can provide the basic for the ejector designing. (2011) Trans Tech Publications.

Design of Co-path Scanning Long Trace Profiler for Measurement of X-ray Space Optical Elements 会议论文 OAI收割
2010
Shun L.; Yan G.; Wei Z.; Yang Z.

收藏 | 浏览/下载：9/0 | 提交时间：2013/03/28

Design of co-path scanning long trace profiler for measurement of X-ray space optical elements (EI CONFERENCE) 会议论文 OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
Shun L.; Yan G.; Wei Z.; Yang Z.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

The Long Trace Profiler (LTP) is a precision surface slope error measurement instrument used in synchrotron radiation optics for many years. By making some modifications to the LTP system we developed a co-path scanning LTP (CSLTP) system to test the cylindrical aspherical surface which used in X-ray space optics. To reduce the mistake caused by air turbulence and manufacture faults of optical elements used the CSLTP is designed with the least difference between the testing beam path and the reference beam path. Also it uses multiple-beam interference but double beam interference to reduce the width of beam fringe. This improves the position precision of the beam fringe on the image plane. 2010 SPIE.

Influence of spacial temperature distribution on high accuracy interferometric metrology 会议论文 OAI收割
2010
作者: Yan F.; Yan F.

收藏 | 浏览/下载：6/0 | 提交时间：2013/03/28

Linearity measurement for image-intensified CCD (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang L.; Zhao Y.; Zhao Y.; Zhao Y.; Yan F.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

To the characteristic of the ultraviolet CCD (UV ICCD) technique of the linearity measurement of the UV ICCD camera is studied based on the theory of radiometry. Approach of linearity measurement is discussed and a kind of measurement system of the UV ICCD has been developed based on the method of neutral density filter. It is very important that the transmittance of the filter is independent of the wavelength in the method of neutral density filter. Black metal screen mesh with different transmittance is used in our system and calibration of the filters' transmittance in different working positions has been done. Meanwhile to assure the uniform of the received radiation on the target of the detector at any test points an integrating sphere is placed behind the neutral filter to balance light. The whole measurement system mainly consists of a deuterium lamp with high stabilization the attenuation film with transmission integrating sphere optical guide and electro-shift platform. Auto control is realized via special software during the test. With this instrument the linearity of the UV ICCD was measured. Experimental results show that the nonlinearity of the UV ICCD under fixed-gain is less than 2% and the uncertainty of measurement system is less than 4%. 2010 Copyright SPIE - The International Society for Optical Engineering.

Temperature characteristics of high power vertical cavity surface emitting lasers (EI CONFERENCE) 会议论文 OAI收割
Semiconductor Lasers and Applications III, November 12, 2007 - November 13, 2007, Beijing, China
作者: Qin L.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

By using oxidation confinement technology high power vertical-cavity surface-emitting lasers are fabricated in experiment. The electrical and optical performance characteristics such as threshold current efficiency emission wavelength and output power are measured under continuous wave (CW) condition at room temperature. The maximum output power is up to watt regime at wavelength of about 980nm. The temperature characteristics of the device are investigated experimentally in detail. The variation in lasing threshold current with temperature is studied. The characteristic temperature T0 of the device is derived and the value is about 211K. Such a high characteristic temperature T0 of threshold current can lead to good temperature sensitivity of the device. At the same time the lasing spectrum characteristics with temperature are also measured. The wavelength shift with temperature is just about 0.06nm/K. From the measured results it is shown that the device can still operate at high temperature condition.

Vertical-external-cavity surface-emitting lasers: Numerical simulation, and characterization (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Materials and Devices III, October 27, 2008 - October 30, 2008, Hangzhou, China
作者: Qin L.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

Firstly the vertical external-cavity surface-emiting lasers (VECSELs) device structure and model was given and the output characteristic was simple calculated. Then in experiment the VECSELs were grown bonded on to the heat sink and optically pumped by high-power 808nm diode laser array with fiber output module the light emission spectra were measured. Finally The thermal characteristic of the VECSELs was investigated by changing the temperature of the substrate. 2008 SPIE.

Large aperture low threshold current 980nmVCSELs fabricated with pulsed anodic oxidation (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China
Jinjiang C.; Yongqiang N.; Te L.; Guangyu L.; Yan Z.; Biao P.; Yanfang S.; Lijun W.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

Pulsed anodic oxidation technique a new way of forming current blocking layers was successfully used in ridge-waveguide QW laser fabrication. We apply this method in 980nm VCSELs fabrication to form a high-quality native oxide current blocking layer which simplify the device process. A significant reduction of threshold current and a distinguished device performance are achieved. The 500m-diameter device has a current threshold as low as 0.48W. The maximum CW operation output power at room temperature is 1.48W. The lateral divergence angle //and vertical divergence angle are as low as 15.3 and 13.8 without side-lobes at a current of 6A.