中国科学院机构知识库网格系统: 检索

Introducing a special collection of papers in the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite: Insight-HXMT 期刊论文 OAI收割
Journal of High Energy Astrophysics, 2020, 卷号: 27, 页码: 51-52
作者: HXMT

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Astrophysics - High Energy Astrophysical Phenomena Abstract: Insight-HXMT is the first Chinese X-ray astronomical mission, launched successfully on June 15, 2017, from China's Jiuquan Satellite Launch Center. Insight-HXMT was designed to have a broad energy coverage in X-rays, from 1-250 keV, with excellent timing and adequate energy resolution at soft X-rays, and the largest effective area at hard X-rays. This allows, in particular, to observe bright sources like X-ray binaries (XRBs) in their bright/outburst states with high cadence and high statistics at hard and soft X-rays at once. It was then expected that the Insight-HXMT mission will bring us new insights regarding the characteristics of several source classes. Examples include characterizing High-Mass X-ray Binaries (HMXBs) and the outburst evolution of Low-Mass X-ray Binaries (LMXBs). For instance, in HMXB systems, the region around their Alfven radius that is responsible to determine whether accretion or propeller occurs, or the region around the NS magnetic pole where the intense X-rays are supposed to be produced are specially appealing targets of study. For the LMXBs, the evolution the outburst and the properties of the compact objects themselves are obvious priority targets for Insight-HXMT. Due to the broad coverage in energy, Insight-HXMT is specially well suited to study the influence of thermonuclear (type-I) X-ray bursts upon the surrounding environment.

Analysis of zenith pass problem and tracking strategy design for roll-pitch seeker (EI CONFERENCE) 会议论文 OAI收割
作者: Jiang H.

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Roll-pitch seeker is currently applied in particular missiles. There is a stubborn problem called zenith pass problem while roll-pitch seeker is used. Analysis of the zenith pass problem which always results in loss of target is presented in this paper. Based on the analysis result tracking strategy is carried out to deal with zenith pass problem. To prove the validity of tracking strategy a practical roll-pitch seeker was accomplished. Model identification and common PID controllers for the physical roll-pitch seeker are taken on after that both disadvantages derived from zenith pass problem in tracking process and meliorated phenomenons by the tracking strategy are shown. It is concluded that the tracking strategy designed for solving the zenith pass problem is efficient. 2011 Elsevier Masson SAS. All rights reserved.

Experimental study on formability of bulk metallic glass as mold for microstructure replication (EI CONFERENCE) 会议论文 OAI收割
作者: Liu J.; Lin J.; Huang Y.; Liu J.; Liu J.

收藏 | 浏览/下载：51/0 | 提交时间：2013/03/25

La62Al14Cu12Ni12BMG is introduced as a substitute for silicon which was widely used as mold material for nanofabrication. For the purpose of precise microstructure replication and complete filling effects of various imprint parameters including imprint temperature imprint time and compression load on formability of La 62Al14Cu12Ni12BMG are studied and discussed. Scanning electron microscope images and results of thermal analysis are used to characterize the filling effect of La62Al 14Cu12Ni12BMG. In particular correlations between time and thermodynamic properties are presented. Despite of its high viscosity at crystallization temperature and its narrow supercooled liquid region La62Al14Cu12Ni12BMG is proved to be a durable and promising material which can precisely replicate the patterns of silicon mold and then transfer its own patterns on Ce 69Al10Cu20Co1BMG and PMMA. 2012 Elsevier B.V. All rights reserved.

Double inverted pendulum control based on three-loop PID and improved BP neural network (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Digital Manufacturing and Automation, ICDMA 2011, August 5, 2011 - August 7, 2011, Zhangjiajie, Hunan, China
作者: Fan Y.

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To deal with the defects of BP neural networks used in balance control of inverted pendulum such as longer train time and converging in partial minimum this article reaLizes the control of double inverted pendulum with improved BP algorithm of artificial neural networks(ANN) builds up a training model of test simulation and the BP network is 6-10-1 structure. Tansig function is used in hidden layer and PureLin function is used in output layer LM is used in training algorithm. The training data is acquried by three-loop PID algorithm. The model is learned and trained with Matlab calculating software and the simuLink simulation experiment results prove that improved BP algorithm for inverted pendulum control has higher precision better astringency and lower calculation. This algorithm has wide appLication on nonLinear control and robust control field in particular. 2011 IEEE.

Design of data transmission speed for small high resolution satellite (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Transportation, Mechanical, and Electrical Engineering, TMEE 2011, December 16, 2011 - December 18, 2011, Changchun, China
Wang S.; Jin G.

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The particular data-transmission time of one small satellite in its data-receiving stations is given by simulateing its orbit and data-receiving stations on earth and the average data-transmission speed is calculated. The average data-transmission speed is taken as the lower limit of speed other different data-transmission speeds are selected and simulated respectively the rule of satellite memory used is found. Basing on the relationship between data-transmission speed and memory on board and considering the worst case the better speed arrived. In the end with different satellite tasks the appropriate speeds are selected which are verified to satisfy the mission. 2011 IEEE.

Restoration of an atmospherically blurred image based on physical model fusion approach (EI CONFERENCE) 会议论文 OAI收割
2010 IEEE 10th International Conference on Signal Processing, ICSP2010, October 24, 2010 - October 28, 2010, Beijing, China
作者: Wang Y.; Li J.; Li J.; Li J.; Wang Y.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

This paper proposes a new restoration method only using the single image information combining atmospheric physical model with fusion techniques to reduce the degradation of the image contrast in bad weather conditions caused by atmospheric aerosols such as haze and fog. The basic idea of this method is to utilize physics-based model method instead of multisensors to generate a serial of virtual images and then to fuse those virtual images into a high contrast image based on the wavelet fusion technique. In contrast to previous methods our restoration technique is not only independent on predicted structure distributions of scene reflectance or detailed knowledge about the particular weather condition but also adapt to the situation without a reference image or images with moving objects captured by a video camera. Experiments on different poorcontrast images demonstrate the availability of the proposed method in case of restoring the atmospherically blurred images. 2010 IEEE.

Athermal design of hybrid refractive/harmonic diffractive optical system for far-infrared multi-band (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: Liu Y.; Liu Y.; Zhang H.; Zhang H.; Sun Q.

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In order to get enough information about the target avoid big chromatic aberration as a result of wide spectrum and the complexity of optical system and adapt different special environment temperature a hybrid refractive/harmonic diffractive optical system in far-infrared multi-band is described in the paper. This diffractive optical system has been designed an athermalized multi-band imaging system with harmonic diffractive element in 15-50m spectrum based on larger 1dispersion capability and particular thermal dispersive power of harmonic diffractive element. Then at the temperature range from 0C to 40C this design can simultaneously meet with all requirements of the imaging system in five harmonic wave bands including15.8-16.2m 18.5-20m 23-25m 30.5-33.5m and 46-50m. In each harmonic wave band the magnification changes as a function of wavelength which creates image registration error. To compensate this shortcoming a zoom optical system is designed with three lenses by means of optical two- component method. The design results show that the hybrid refractive/harmonic diffractive optical system can realize athermalized and achromatic design and the zoom optical system makes half image height at 3.53mm in every harmonic wave band and still realizes aberration compensation action. In the five harmonic wave bands each optical transfer function approaches the diffraction limit at ambient temperature range of 0C to 40C. Finally the system realizes the requirements of portability mini-type and ease for fabrication. 2009 SPIE.

Non-contact and on-line cone diameter measuring based on high speed linear CCD (EI CONFERENCE) 会议论文 OAI收割
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 2, 2005 - November 5, 2005, Zian, China
Guohui Z.; Jianhua W.

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The remarkable improvement of sensing and processing hardware performance makes the non-contact on-line high accuracy and high speed measuring possible by means of linear CCD. The goal of this pager is to describe the key questions on designing the cone diameter detecting system by linear CCD. This paper first describes the detecting scheme. In particular the factors affecting accuracy such as resolution voltage difference between neighbor pixels detecting rate and so on are analyzed and the quantitative estimation equations are provided. CCD takes on the photoelectric translation and measuring component double functions so the waveform of CCD output signal and the affecting factors merit deep discussion. On the basis of discussion several principles that can be used to improve the boundary recognition accuracy are presented.

CMOS APS imaging system application in star tracker (EI CONFERENCE) 会议论文 OAI收割
Advanced Materials and Devices for Sensing and Imaging II, November 8, 2004 - November 10, 2004, Beijing, China
作者: Li J.; Liu Y.; Liu Y.; Liu Y.; Liu J.

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Small satellites are capable of performing space explore missions that require accurate attitude determination and control. However low weight size power and cost requirements limit the types of attitude sensor of small craft such as CCD are not practical for small satellites. CMOS APS is a good substitute for attitude sensors of small craft. Some of the technical advantages of CMOS APS are no blooming single power low power consumption small size and little support circuitry direct digital output simple to system design in particular radiation-hard characteristic compare with CCD. This paper discusses the application probability of CMOS APS in star tracker for small satellites further more a prototype ground-based star camera based on STAR250 CMOS image sensor has been built. In order to extract stars positions coordinates subpixel accuracy centroiding algorithm has been developed and tested on some ground-based images. Moreover the camera system star sensitivity and noise model are analyzed and the system accuracy is been evaluated. Experimental results indicate that a star camera based on CMOS APS is a viable practical attitude sensor appropriate for space small satellites.

Manufacturing and Testing SiC Aspherical mirrors in Space telescopes (EI CONFERENCE) 会议论文 OAI收割
ICO20: Optical Devices and Instruments, August 21, 2005 - August 26, 2005, Changchun, China
作者: Fan D.; Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

Reaction Bonded (RB) SiC mirrors due to their excellent specific stiffness and thermal properties have been widely used in space telescopes. However polishing large SiC aspherical mirrors is difficult compared to other materials such as fused silica or Zerodu. In addition surface roughness of the polished SiC mirrors is limited by the defects of the materials and needs to be improved by means of surface coating technique. This paper introduces the current progress of large SiC aspherical mirrors manufacturing and testing in CIOMP. In particular the procedures of making large off-axis aspherical mirrors were discussed in detail. A proprietary computer controlled optical surfacing (CCOS) technique was utilized to grind and polish the mirrors and the computer aided null test was used to measure the surface figure. As results a 600mm class off-axis SiC aspherical mirrors was demonstrated with figure error less than 13nm rms.