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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 \| 收藏 \| 浏览/下载：44/0 \| 提交时间：2022/02/08 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.
	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：141/0 \| 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.
	An image matching algorithm based on sub-block coding (EI CONFERENCE) 会议论文 OAI收割 2nd International Workshop on Computer Science and Engineering, WCSE 2009, October 28, 2009 - October 30, 2009, Qingdao, China 作者: Li S. 收藏 \| 浏览/下载：32/0 \| 提交时间：2013/03/25 In order to improve the speed of matching algorithm and simplify the processing of existing sub-block coding matching a new template matching method combined local gray value encoding matching and phase correlation is proposed. Matching process is divided into rough matching and fine matching. Rough matching divides the image into certain size blocks called R-block sums the gray value of each R-block pixel encodes the R-block according to the gray value distribution of R-block with the adjacent R-block and matches by step between the template and each search sub-image. Then fine matching results are obtained using phase correlation according to initial match parameters. The time complexity of the proposed method is (M2) .The new algorithm is faster than traditional algorithm by two orders of magnitude and the speed has improved twice compared with existing sub-block coding method. Experiments demonstrate that the new algorithm is robust to the linear transformation of pixel grey value and image noise and it also has the stability of small-angle rotation. 2009 IEEE.
	Characteristics of ZnMgO-based metal-semiconductor-metal photodetectors (EI CONFERENCE) 会议论文 OAI收割 International Symposium on Photoelectronic Detection and Imaging, ISPDI 2007: Photoelectronic Imaging and Detection, September 9, 2007 - September 12, 2007, Beijing, China 作者: Zhang J.; Li B.; Li B.; Li B.; Zhao Y. 收藏 \| 浏览/下载：23/0 \| 提交时间：2013/03/25 In recent years ZnMgO semiconductor alloys with a direct bandgap tunable between 3.37 eV and 7.8 eV become one of the most suitable materials for the fabrication of ultraviolet detectors. In this paper we have fabricated metal-semiconductor-metal photodetectors on 1-m thick Zn 0.8Mg0.2O films. The interdigital metal electrodes are 500 m long and 5 m wide with an interelectrode spacing 2 m 5 m and 10 m respectively. Zn0.8Mg0.2O films were grown on quartz by ratio frequency magnetron sputtering at 500C. Dark current spectral responsivity and pulse response were carried out for the devices with different finger pitches. All the photodetectors showed the peak responsivity at 330 nm and the ultraviolet-visible rejection ratio (R330 nm/R400 nm) is more than four orders of magnitude at 3 V bias. For the device with 2 m finger pitch the detectivity was calculated as 4.21011 cm Hz 1/2/W at 330 nm. Furthermore the transient response measurement for all devices revealed similar rise time of 10 ns. The 90%-10% fall times are 130 ns 170 ns and 230 ns for the devices with different finger pitches of 2 m 5 m and 10 m respectively..
	Linear chirp control of infrared signal in a biased semiconductor thin film 期刊论文 OAI收割 new j. phys., 2008, 卷号: 10, 页码: 83018 Luo Jian; 钮月萍; Cui Ni; Zhang Hongjun; 金石琦; 龚尚庆收藏 \| 浏览/下载：1183/89 \| 提交时间：2009/09/18 Chirp rates Chirped pulses Infrared spectra Light-matter interactions Linear chirp Orders-of-magnitude Spectral intensities