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No pulsed radio emission during a bursting phase of a Galactic magnetar 期刊论文 OAI收割
Nature, 2020, 卷号: 587, 页码: 63-65
作者: HXMT

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Astrophysics - High Energy Astrophysical Phenomena Abstract: Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances^1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources^4-13, but no convincing evidence has been collected so far¹⁴. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft íray bursts¹⁵. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft íray/hard-X-ray flare^18-21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-íray repeater (SGR) bursts were detected in íray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.

Data normalization of single camera visual measurement network system (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Information Technology and Management Innovation, ICITMI 2012, November 10, 2012 - November 11, 2012, Guangzhou, China
作者: Zhang Y.-C.; Zhou J.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

With the development of visual measurement system Normalize the measured coordinates into the same world coordinate system Apply in the three coordinate measuring machine(CMM) to have the simulation experiment So the data normalization has the advantage of more high precision. (2013) Trans Tech Publications the visual measurement system of single camera which applied in the imaging theory of optical feature points then get the global data the result indicates that the maximum absolute tolerance between the normalization coordinates via the center of point set and the ones measured by CMM directly is 0.058mm Switzerland. it has been widespread used in the modern production. Due to the limit of the environment in scene and achieve the overall measurement the visual measurement system of single camera could not measure the shield between the measured objects each other. Focus on this problem But the one between the coordinate repeatedly measured at the position of one network control point is 0.066mm present a kind of the the knowledge of measurement network based on the visual measurement of single camera set up the measurement network system via the multi-control points. Measure the optical feature points in every network control point via the visual measurement system of single camera

The application of adaptive enhancement algorithm based on gray entropy in mammary gland CR image (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012, April 21, 2012 - April 23, 2012, Three Gorges, China
Zhang M.-H.; Zhang Y.-Y.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

Mammary gland is composed entirely of soft tissue with approximate density therefore mammary gland CR medicine radiation image presents a low contrast and slight difference changes may be a manifestation of tumor so it is necessary to enhance mammary gland CR image to improve its visual quality in order to meet the demands of doctor's clinical diagnosis. However the general enhancement algorithms over enhance the contrast and noise due to image details lost aiming at the defects a mammary gland CR medicine image adaptive enhancement arithmetic based on image gray entropy is put forward. The arithmetic adapts dizzy image to magnify selected spatial frequency response in order to enhance the edge details of mammary gland CR images. It can adjust weighted factor K according to image gray characteristics namely pixel gray entropy. Experiments results demonstrate that mammary gland CR image enhanced by the algorithm has abundant details and high signal-to-noise ratio moreover CR image enhanced has good visual effect. So the method is effective and fit for enhancing CR medical radiation image edge details. 2012 IEEE.

Stray light analysis of solar photoelectric detection system on space target (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Intelligent System and Applied Material, GSAM 2012, January 13, 2012 - January 15, 2012, Taiyuan, Shanxi, China
Li L.-Y.; Wang Y.-F.; San X.-G.

收藏 | 浏览/下载：143/0 | 提交时间：2013/03/25

Most conventional spacious solar photoelectric detection systems suffer from unexpected stray light. This paper demonstrates the effects on photoelectric detection system bring out by stray light. On this foundation build up evaluation index of stray light system to search the reasonable programme to eliminating stray light. A detailed telescope system geometry model was created and scatter models were create for telescope and enclosure components. By the means of designing the structure of main baffle baffle vane and the coating technology. In order to verify the prosperity of structure that designed we utilizes software to analysis opto-mechanical model. we utilizes software to analysis opto-mechanical model. The simulations show that point source transmittance of the system is thus reduced by up to two orders of magnitude between 10-8 and 10-10. Meanwhile the experiment obtains clean detection data which satisfies the system requirements. Stray light has been suppressed effectually and so measurement precision was improved from detection graphics. (2012) Trans Tech Publications.

Research on the key technology of ATP system for free space optical communication (EI CONFERENCE) 会议论文 OAI收割
31st Chinese Control Conference, CCC 2012, July 25, 2012 - July 27, 2012, Hefei, China
Meng H.; Liu X.; Zhang B.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

Free space optical communication is the bidirectional transmission technology that puts to use the laser beam as a carrier in space. Free space optical communication is generally used in the severe space environment. It is the mainly problem that the narrow beam of laser beam is high-precision aimed. and it is became very important that the technology of ATP is researched. Performance of the ATP system directly affects the performance of the quality of the free space optical communication. So research of the ATP is the key technology in FSO and this technology is discussed and analysed in the article. 2012 Chinese Assoc of Automati.

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.

收藏 | 浏览/下载：38/0 | 提交时间：2013/03/25

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.

Embedded image grabber and processing system based on camera link (EI CONFERENCE) 会议论文 OAI收割
2012 World Automation Congress, WAC 2012, June 24, 2012 - June 28, 2012, Puerto Vallarta, Mexico
作者: Wang Z.; Zhao Y.; Zhao Y.; Zhao Y.; Wang Z.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

In order to realize real-time measurement based on image proposes a design project of embedded image grabber and processing system based on camera link interface. The system adopts FPGA+DSP structure design. DSP used to process the image and send out processing results to external. FPGA adopts modularize design. It contains camera link interface module image memory module DSP connection module and so on. The experiment results show that the system design flexibility small cubage high real-time image processing and can fulfil the requirement of real-time measurement. 2012 TSI Press.

Precision analysis of simulation systems with hardware-in-loop caused by performance of three-Axis virtual flight motion simulator (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Manufacturing Science and Technology, ICMST 2011, September 16, 2011 - September 18, 2011, Singapore, Singapore
Wang T.; Zhu M.-C.; Yin S.-L.; Jia H.-G.

收藏 | 浏览/下载：50/0 | 提交时间：2013/03/25

Simulation systems with hardware-in-loop are composed by three-Axis virtual flight motion simulator simulation computer load torque simulator and visual simulation systems. Three-Axis Virtual Flight Motion Simulator are used to simulate the attitude of missile in simulation system with hardware-in-loop so its performance influenced the result of simulation directly. This paper mainly analyzed the factors which influenced the performance of a three-Axis virtual flight motion simulator which we are used now in the lab then analyzed the entire simulation system's error caused by these factors through numerical simulation method. By analysis we can see that bandwidth is the main factor influenced the precision of simulation systems with hardware-in-loop mechanical device installation error and measurement error may also cause some errors of the systems at the same time.

Research on load-bearing characteristics of precision air-bearing rotary stage (EI CONFERENCE) 会议论文 OAI收割
3rd international Conference on Manufacturing Science and Engineering, ICMSE 2012, March 27, 2012 - March 29, 2012, Xiamen, China
作者: Wang L.; Wang L.; Wang L.; Lin J.

收藏 | 浏览/下载：117/0 | 提交时间：2013/03/25

Air-bearing is a core component of air-bearing rotary stage. The weakness that the air-bearing has the low load capacity and stiffness has been concerned about by domestic and foreign scholars. So how to improve the load capacity and stiffness has become a serious problem. In order to improve the load capacity and stiffness of the air-bearing rotary stage in this paper we improved structure of Zhang Wenjie and others' high-precision direct-drive air-bearing rotary stage. The gas film of air-bearing has been meshed by GAMBIT software and we use FLUENT software to obtain the carrying capacity features of the gas film. Finally the structural static force of the precision air-bearing rotary stage will be analyzed by ANSYS software. The analysis results show that: the structural design of the precision air-bearing rotary stage is reasonable and this structure can provide a larger range of loads. Even in heavy load conditions a larger deformation will not occur any more. It has a good practical value and also can be widely used in high precision equipments. (2012) Trans Tech Publications.