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Insight-HXMT observations of Swift J0243.6+6124: the evolution of RMS pulse fractions at super-Eddington luminosity 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 497, 页码: 5498-5506
作者: HXMT

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stars: neutron pulsars: individual: Swift J0243.6+6124 X-rays: binaries Astrophysics - High Energy Astrophysical Phenomena Abstract: Based on Insight-HXMT data, we report on the pulse fraction evolution during the 2017-2018 outburst of the newly discovered first Galactic ultraluminous X-ray (ULX) source Swift J0243.6+6124. The pulse fractions of 19 observation pairs selected in the rising and fading phases with similar luminosity are investigated. The results show a general trend of the pulse fraction increasing with luminosity and energy at supercritical luminosity. However, the relative strength of the pulsation between each pair evolves strongly with luminosity. The pulse fraction in the rising phase is larger at luminosity below 7.71 × 10³⁸ erg s^-1, but smaller at above. A transition luminosity is found to be energy independent. Such a phenomenon is first confirmed by Insight-HXMT observations and we speculate that it may have relation with the radiation-pressure-dominated accretion disc.

Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文 OAI收割
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：42/0 | 提交时间：2013/03/25

Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror semiconductor lasers as light source and CCD sensor as receiver. The system is smaller lighter and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

KW-output high beam quality diode laser array source (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者: Zhang J.; Wang L.; Wang L.; Wang L.; Liu Y.

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With the advantages of small volume light weight high efficiency and long lifespan diode laser has been widely applied to industrial processing. Presently for laser used as processing light source needs to amount to dozens of KW per cm2 of power density how to increase power output and get smaller light spot for diode laser becomes a key problem. It is introduced that by designing beam shaping by ourselves and making use of optical system for beam blooming and focusing 808nm laser array composed of 20 bars eventually achieves the 1001.5w power output coupling efficiency at 90% 11mm2 of light spot through experiments which enables diode laser to be directly applied to cladding welding and so on. 2012 IEEE.

Comparison of radiation temperature measurement precision between middlewave and longwave thermal-imaging systems (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者: Sun Z.

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A comparison study on temperature measurement precision between middlewave 3-5m and longwave 8-12m measuring thermal imaging systems has been conducted. The study was limited to systems working in indoor conditions and the target's temperature is in the range of 270K900K. First the Disturb Resisting Function (DRF) of infrared systems is deduced. On the base of DRF curve we find that the middlewave infrared system get the smaller influences under the same size disturb compared with the longwave system. A theory of the influence of target's physical characteristic and measurement conditions on the accuracy of temperature measurements has been developed. On the basis of the developed formulas an analysis of the influence of signal disturbances (because of incorrectly assumed emissivity limited transmittance of the atmosphere radiation reflected by the object and shift of optics radiation) on the accuracy of temperature measurement has been made. It has been found that the middlewave systems in typical temperature range offer generally better accuracy in temperature measurement than the longwave ones do. 2012 IEEE.

Correction of shear creep compliance determined by conical indentation 会议论文 OAI收割
23rd International Congress of Theoretical and Applied Mechanics, 中国北京/Beijing, China, 2012-08-19
作者:

收藏 | 浏览/下载：20/0 | 提交时间：2014/04/02

indentation creep conical shear compliance determined angle uniaxial large smaller relaxation determination ratio theoret tension result error found Poisson equal

The design of chisel-edge ruling tool for diffraction gratings (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
作者: Zhang F.; Zhang F.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

The process of parameters design on chisel-edge ruling tool of diffraction grating which is inefficient and highly costive needs plenty ruling experience came from a series of ruling test to optimize and design it. In order to reduce the choosing range of experiential design parameters on chisel-edge grating ruling tool to improve efficiency and to reduce costs this paper summarize the experimental results of several gratings ruling process for the experiential design on parameters of chisel-edge ruling tool. Provide the specific parameters choosing range as follows: that the blaze angle and directional angle difference in less than 3 the bottom angle and apex angle difference in less than 5. Apex angle larger than the groove bottom angle in conventional grating while apex angle smaller than the bottom angle in echelle grating and the directional angle smaller than blaze angle in both condition. 2011 IEEE.

The Research of real time auto-recognition of the moire fringe (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Wang M.-J.; Wu Z.-G.

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Measuring the movement of raster by the method of moire fringe has the advantage of high sensitivity high resolution and non-contacted measurement. The characteristic of moire fringe is that the image is white alternate with black the angle of the stripes is uniform the width of the stripes is uniform the terminators of the stripes aren't clear. A fast method that can figure out the width and angle of the moire fringe precisely is put forward in this paper. It calculates the angle the stripes firstly. According to the principle of the minimum mean squared error (MMSE) the closer a series of data is the smaller the value of the MMSE will be. The method is described as follows: It takes the image's center as the origin 180 beelines pass through the origin with the same angle interval. it calculates the value of the minimum mean squared error of the 180 beelines and find out the least one among those then the angle of the moire fringe comes out primarily. In order to improving the calculating precision of moire fringe 60 equal angles are divided in the neighborhood of the angle then a precise angle of moire fringe is calculated according to the principle of the MMSE. After getting out the angle of the moire fringe we begin to calculate the width of moire fringe. A line vertical with the moire fringe is drawn and we can get the width of the moire fringe by the vertical line. In order to get over the influence of the noise an effective area with the shape of diamond is selected in the image. The data of area is accumulated and projected according to the direction of moire fringe and a sine curve come out. The width of moire fringe can be obtained by getting the position of the first wave crest the position of the last wave crest and the number of wave crest. Experiments prove that the precision of the method put forward in this paper is enhanced in comparison with the traditional frequency method the precision of width calculation achieves to 99.6% according to the evaluation indicators of width detection error. The computing speed is boosted largely compared with traditional method and it can achieve with 15 ms that satisfying the demand of real time. 2011 SPIE.

Gimbal displacement error analysis on an electro-optical seeker (EI CONFERENCE) 会议论文 OAI收割
Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

It is essential to analyze the gimbal displacement errors for a seeker due to the importance for cueing of targets and tracking for the final approach. Otherwise for a seeker electro-driven with a concentric glass dome the large errors will decrease the picking pointing and tracking precision rooted from the displacement errors existing between the rotation center of the optical system and the gimbal. And the gimbaled camera system displacement errors are never eliminated but reduced due to the geometric errors consists of geometric tolerances of gimbal structure manufacture installation and vibration coming from working environment. In this paper the gimbal displacement errors in an electro-optically stabilized platform resulting from geometric errors and environment errors were analyzed and shown in detail. The mathematical modal of the gimbal displacement errors created based on multi-body dynamics demonstrated the connection between the gimbal displacement errors and the stabilized platform. Taking a visible light image seeker as a case the diameter is 120mm and the geometric tolerances came from the values of primary design and the vibration data came from the environmental vibration test on the pitch-yaw seeker and at the same time the errors resulting from installation were considered too. Based on calculating the maximum gimbal displacement error will reach to 0.2mm for pitching angle smaller than 40 and yawing angle smaller than 60. However the critical parts have been found out according to the probability theory and the reliability analysis successfully used in the paper and finally the maximum gimbal displacement error reduced to 0.1mm which is acceptable corresponding to the picking pointing and tracking precision for an optical imaging seeker. 2010 Copyright SPIE - The International Society for Optical Engineering.

Miniaturize photoelectric stable platform (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer Application and System Modeling, ICCASM 2010, October 22, 2010 - October 24, 2010, Shanxi, Taiyuan, China
Xue W.-Q.; Wang Y.-Y.; Dai M.

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In order to reduce the size and weight of the gimbal in a traditional stable platform and correct the disadvantage in size of the payload the paper first improves the gimbal which is an important component of a stable photoelectric platform that also is an important factor in affecting the size and weight of a stability platform. In this paper a closed-form solution of 3-DOF manipulator is designed according mechanical arm design principles. This manipulator is formed by a three joint axes whose extended line is intersected at one point. A standard orthogonal coordinate system is set up for each rod in the manipulator. And then rotation transformation matrix expression is obtained. At last in this paper the manipulator arm-shaped method for solving solutions is description and also each parameter of the gimbal is calculated when the photoelectric detection devices at bottom reach the expected position. Test results show that the photoelectric stability platform with gimbal we designed is smaller lighter and simpler than that traditional. Also the packaging and size of the photoelectric will not be affected with this open structure. 2010 IEEE.

Small roll angle measurement based on auto-collimation and moire fringe (EI CONFERENCE) 会议论文 OAI收割
2009 International Conference on Optical Instruments and Technology - Optoelectronic Measurement Technology and Systems, October 19, 2009 - October 22, 2009, Shanghai, China
Bai X.-G.; Cai S.; Qiao Y.-F.; Dai M.

收藏 | 浏览/下载：32/0 | 提交时间：2013/03/25

A novel method for small roll angle measurement based on auto-collimation and moire fringe is presented. A right-angle prism is used as an indicator of small roll angle around the optical axis and a CCD is used to collect moire fringes that are generated by scale grating image which is reflected by prism and index grating. Any small roll angle of the prism will change the include angle of the grating pair and meanwhile induce a change in the moire fringe period. The relationship between roll angle and period of moire fringes is established. The period data is obtained by image processing. The experimental result certifies that the principle of small angle measurement method based on auto-collimation and moire fringe is correct and feasible. The measuring error is smaller than 0.2 within 7 range compared with 0.2 autocollimator. 2009 SPIE.