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Development and radiance calibration of three-waveband camera (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photonics and Optoelectronics, SOPO 2010, June 19, 2010 - June 21, 2010, Chengdu, China
作者:  Wang J.;  Liu Y.;  Liu Y.;  Sun Q.;  Liu Y.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
An imaging system with three-waveband sharing one lens and an area CCD was developed. By rotating different filters into the beam path  the required waveband was selected. The optical system which can image in ultraviolet  visible and near infrared region was designed and the signal collecting system was integrated. The optical design and system integration have some advantages such as low cost  small size and light in weight. To obtain a high imaging quality  the radiation calibration is carried out in order to establish the relation between the average grey level of output image and the input radiance from the integrating sphere. According to the calibration data in experiments  the radiation dynamic range and the best working point of the system are determined. The experiment result shows that the dynamic range of the image system is maximal when the exposure time is 8ms in ultraviolet  0.5ms in visible and 0.125ms in near infrared region. 2010 IEEE.  
High power VCSEL device with periodic gain active region (EI CONFERENCE) 会议论文  OAI收割
Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China
作者:  Zhang Y.;  Liu Y.;  Liu Y.;  Liu Y.;  Qin L.
收藏  |  浏览/下载：31/0  |  提交时间：2013/03/25
High power vertical cavity surface emitting lasers with large aperture have been fabricated through improving passivation  lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structure  a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure  with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the cavity to enhance the coupling between the optical field and the gain region. Large aperture and bottom-emitting configuration was used to improve the beam quality and the heat dissipation. A maximum output power of 1.4W was demonstrated at CW operation for a 400m-diameter device. The lasing wavelength shifted to 995.5nm with a FWHM of 2nm at a current of 4.8A due to the internal heating and the absence of active water cooling. A ring-shape farfield pattern was induced by the non-homogeneous lateral current distribution in large diameter device. The light intensity at the center of the ring increased with increasing current. A symmetric round light spot at the center and single transverse mode operation with a divergence angle of 16 were observed with current beyond 4.8A.  
Development of a new diffuse near infrared food measuring (EI CONFERENCE) 会议论文  OAI收割
Sitxh International Symposium on Instrumentation and Control Technology: Signal Analysis, Measurement Theory, Photo-Electronic Technology, and Artificial Intelligence, October 13, 2006 - October 15, 2006, Beijing, China
作者:  Zhang J.;  Zhang J.;  Zhang J.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
Industries from agriculture to petrochemistry have found near infrared (NIR) spectroscopic analysis useful for quality control and quantitative analysis of materials and products. The general chemical  polymer chemistry  petrochemistry  agriculture  food and textile industries are currently using NIR spectroscopic methods for analysis. In this study  we developed a new sort NIR instrument for food measuring. The instrument consists of a light source  12 filters to the prismatic part. The special part is that we use a mirror to get two beams of light. And two PbS detectors were used. One detector collected the radiation of one light beam directly and the value was set as the standard instead the standard white surface. Another light beam irradiate the sample surface  and the diffuse light was collected by another detector. The value of the two detectors was compared and the absorbency was computed. We tested the performance of the NIR instrument in determining the protein and fat content of milk powder. The calibration showed the accuracy of the instrument in practice.  
Ultraviolet electroluminescence of ZnO based heterojunction light emitting diode (EI CONFERENCE) 会议论文  OAI收割
12th International Conference on II-VI Compounds, September 12, 2005 - September 16, 2005, Warsaw, Poland
Jiao S. J.; Lu Y. M.; Shen D. Z.; Zhang Z. Z.; Li B. H.; Zhang J. Y.; Yao B.; Liu Y. C.; Fan X. W.
收藏  |  浏览/下载：25/0  |  提交时间：2013/03/25
ZnO/GaN p-i-n heterojunctions light emitting diodes were fabricated by plasma-assisted molecular beam epitaxy. We make use of high resistivity of nitrogen doped ZnO to fabricate n-ZnO/i-ZnO/p-GaN heterojunction light emitting diode. The emission of i-ZnO was obtained due to the limitation effect of i-ZnO on electrons and holes. Moreover  n-ZnO/i-MgO/p-GaN heterojunction light emitting diode was also fabricated. The limitation effect on electrons is increased in this heterojunction. The bright ultraviolet electroluminescence at 382 nm originating from the ZnO layer was observed in the room temperature electroluminescence spectrum. We hope to realize the stimulated emission of ZnO using these heterojunctions by the improvement of crystal quality and the optimization of device structure. 2006 WILEY-VCH Verlag GmbH Co. KGaA.  
Optical diagnostics of laser beam quality for the Beijing Free Electron Laser (BFEL) 期刊论文  OAI收割
Chinese Science Bulletin, 1995, 期号: 19, 页码: 1602-1607
作者:  Fu ES(傅恩生);  Wang ZJ(王之江);  Wang YZ(王玉芝);  Shen GR(沈桂荣);  Wang B(王兵)
收藏  |  浏览/下载：10/0  |  提交时间：2015/12/07
高功率激光近场空间周期性调制补偿技术研究 学位论文  OAI收割
作者:  高雅茹
  |  收藏  |  浏览/下载：31/0  |  提交时间：2018/12/26
高功率激光光束质量提升关键因素研究 学位论文  OAI收割
作者:  雷泽民
  |  收藏  |  浏览/下载：45/0  |  提交时间：2018/12/26