中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共7条，第1-7条

帮助

条数/页：排序方式：
	High-speed focusing and scanning light through multimode fiber 会议论文 OAI收割 Shanghai, China, 2020-10-17 作者: Geng, Yi; Zhang, Zaikun; He, Zhengquan; Chen, Hui; Wang, Ruiduo \| 收藏 \| 浏览/下载：34/0 \| 提交时间：2021/01/20 Light focusing amplitude-only modulation multimode fiber spot-scanning imaging
	High-speed light focusing through multimode fiber for spot-scanning imaging 会议论文 OAI收割 Xi'an, China, 2019-08-06 作者: Chen, Hui; Geng, Yi; Xu, Chengfang; Zhuang, Bin; Ren, Liyong \| 收藏 \| 浏览/下载：92/0 \| 提交时间：2020/03/04 Light focusing phase-only modulation multimode fiber spot-scanning imaging
	In-orbit Demonstration of X-Ray Pulsar Navigation with the Insight-HXMT Satellite 期刊论文 OAI收割 The Astrophysical Journal Supplement Series, 2019, 卷号: 244, 页码: 1 作者: HXMT \| 收藏 \| 浏览/下载：15/0 \| 提交时间：2022/02/08 pulsars: general techniques: miscellaneous Astrophysics - Instrumentation and Methods for Astrophysics Abstract: In this work, we report the in-orbit demonstration of X-ray pulsar navigation with Insight-Hard X-ray Modulation Telescope (Insight-HXMT) Satellite, which was launched on 2017 June 15. The new pulsar navigation method Significance Enhancement of Pulse-profile with Orbit-dynamics is adopted to determine the orbit with observations of only one pulsar. In this test, the Crab pulsar is chosen and observed by Insight-HXMT from 2017 August 31 to September 5. Using the five-day long observation data, the orbit of Insight-HXMT is determined successfully with the three telescopes onboard: High Energy X-ray Telescope, Medium Energy X-ray Telescope, and Low Energy X-ray Telescope, respectively. By combining all the data, the position and velocity of the Insight-HXMT are pinpointed to within 10 km (3ҩ and 10 m s^-1 (3ҩ, respectively.
	Improvement of the performance of the twisted-nematic liquid-crystal display as a phase modulator 期刊论文 OAI收割 applied optics, 2011, 卷号: 50, 期号: 17, 页码: 2588-2593 作者: Ma, Baiheng; Yao, Baoli; Li, Ze; Ye, Tong 收藏 \| 浏览/下载：30/0 \| 提交时间：2012/06/29 SPATIAL LIGHT MODULATORS JONES MATRIX-METHOD ONLY MODULATION POLARIZATION STATES TELEVISION DEVICES
	OFDM baseband modulation technology based on VHDL (EI CONFERENCE) 会议论文 OAI收割 2010 IEEE International Conference on Advanced Computer Control, ICACC 2010, March 27, 2010 - March 29, 2010, 445 Hoes Lane - P.O.Box 1331, Piscataway, NJ 08855-1331, United States Lin L.; Qiao Y.-F.; Su W.-X. 收藏 \| 浏览/下载：16/0 \| 提交时间：2013/03/25 In order to improve the transmission velocity in mulitipath fading wireless channel two main advantages are obtained via discussing spectrum utilization ratio of OFDM. Then the high speed OFDM technology receives increasing attentions in mobile communication. Modulation programs are designed with VHDL based on the principle of OFDM in the paper. First from the results of VHDL simulation after OFDM fundamental is introduced the realization of baseband operations such as interleaver subcarrier modulation IFFT and adding CP are presented. Finally implemented programs are validated on the actual implement system. Experimental results indicate that setup time corresponding to transmission velocity is only 71.05s and steady time is approximately 6 times as setup time that is not only achieving the high speed transmission but also supplying adequate modulation time. 2010 IEEE.
	Optical system of large relative aperture and wide field using aspheric corrector for detecting (EI CONFERENCE) 会议论文 OAI收割 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China 作者: Zhang J.; Zhang J.; Zhang J.; Wang J. 收藏 \| 浏览/下载：22/0 \| 提交时间：2013/03/25 The magnitude requirement of space target detecting determines that the image of detecting telescope should have several performances: small spots the wider field of view small 80% encircled energy diameter and good MTF(Modulation transfer function). So the aperture and field of view of optical system have some demands accordingly. The larger aperture the more extensive range which the telescope searches. Now most of ground telescopes whose apertures are from 500mm to 1000mm is on-axis optical system the more energy that telescope collects and higher magnitude the telescope detects so wide field of view becomes the most importance problem. To obtain large relative aperture and wide field of view the paper introduces a catadioptric telescope with small aperture aspheric refractive corrector whose conic surface will be used to remove the aberrations due to large relative aperture and wide field of view. As to the optical system there is only one aspheric refractive corrector and it is relatively easy for manufacturing because of its concave figure and normal material. The paper gives the example and optimizes this optical system with ZEMAX program. And then the paper provides a specific analysis program for testing the aspheric refractive corrector. The aperture of this optical system is 750mm and its relative aperture is 0.82 and the field of view is 3.6 diameter(diagonal). Its structure is simple and the image quality is also very good. 2009 SPIE.
	The compression and storage method of the same kind of medical images-DPCM (EI CONFERENCE) 会议论文 OAI收割 4th International Conference on Photonics and Imaging in Biology and Medicine, September 3, 2005 - September 6, 2005, Tianjin, China 作者: Liu H.; Liu H.; Liu H. 收藏 \| 浏览/下载：16/0 \| 提交时间：2013/03/25 Medical imaging has started to take advantage of digital technology opening the way for advanced medical imaging and teleradiology. Medical images however require large amounts of memory. At over 1 million bytes per image a typical hospital needs a staggering amount of memory storage (over one trillion bytes per year) and transmitting an image over a network (even the promised superhighway) could take minutes - too slow for interactive teleradiology. This calls for image compression to reduce significantly the amount of data needed to represent an image. Several compression techniques with different compression ratio have been developed. However the lossless techniques which allow for perfect reconstruction of the original images yield modest compression ratio while the techniques that yield higher compression ratio are lossy that is the original image is reconstructed only approximately Medical imaging poses the great challenge of having compression algorithms that are lossless (for diagnostic and legal reasons) and yet have high compression ratio for reduced storage and transmission time. To meet this challenge we are developing and studying some compression schemes which are either strictly lossless or diagnostically lossless taking advantage of the peculiarities of medical images and of the medical practice. In order to increase the Signal to-Noise Ratio (SNR) by exploitation of correlations within the source signal a method of combining differential pulse code modulation (DPCM) is presented.