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Constraining the X-Ray-Infrared Spectral Index of Second-timescale Flares from SGR 1935+2154 with Palomar Gattini-IR 期刊论文 OAI收割
The Astrophysical Journal, 2020, 卷号: 901, 页码: L7
作者: HXMT

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收藏 | 浏览/下载：24/0 | 提交时间：2022/02/08

Radio transient sources Magnetars Soft gamma-ray repeaters 2008 992 1471 Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Instrumentation and Methods for Astrophysics Abstract: The Galactic magnetar SGR 1935+2154 has been reported to produce the first example of a bright millisecond-duration radio burst (FRB 200428) similar to the cosmological population of fast radio bursts (FRBs). The detection of a coincident bright X-ray burst represents the first observed multiwavelength counterpart of an FRB. However, the search for similar emission at optical wavelengths has been hampered by the high inferred extinction on the line of sight. Here, we present results from the first search for second-timescale emission from the source at near-infrared (NIR) wavelengths using the Palomar Gattini-IR observing system in the J band, enabled by a novel detector readout mode that allows short exposure times of ?0.84 s with 99.9% observing efficiency. With a total observing time of ?12 hr (?47,728 images) during its 2020 outburst, we place median 3Ҡlimits on the second-timescale NIR fluence of ?18 Jy ms (13.1 AB mag). The corresponding extinction-corrected limit is ?125 Jy ms for an estimated extinction of A_J = 2.0 mag. Our observations were sensitive enough to easily detect an NIR counterpart of FRB 200428 if the NIR emission falls on the same power law as observed across its radio to X-ray spectrum. We report nondetection limits from epochs of four simultaneous X-ray bursts detected by the Insight-HXMT and NuSTAR telescopes during our observations. These limits provide the most stringent constraints to date on fluence of flares at 10¹⁴ Hz, and constrain the fluence ratio of the NIR emission to coincident X-ray bursts to R_NIR ? 0.025 (fluence index ?0.35).

Laser cleaning of neutral attenuator plate based on low power laser diode (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
作者: Chen Y.; Li L.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

Laser cleaning is a non-contact green and environmental cleaning method which can effectively remove particulate contaminations of sizes as small as 0.1 m without damage to the optics. But most laser cleaning devices are large and heavy also expensive due to using large lasers such as CO2 laser YAG Laser etc. In this work a low power LD was tried to clean fingerprint and dust contaminated on the surface of the attenuator glasses plates. In the laser cleaning experiment with low power diode the fingerprint grease can be efficient to be cleaned but there is no evident effect for cleaning inorganic dust. The cleaning different degree of fingerprint contaminations was investigated at the variable laser parameters including laser power and irradiation time. An optical microscope was used to analyze the cleaning effect. The results show that low power LD can effectively remove the fingerprint on the surface of absorptive-type attenuator glass plates. On the premise that the attenuator optics glasses are not damaged the cleaning area increases with the increase of radiation time and laser power. The cleaning area doesn't change much with the variation of laser frequency when the other parameters are the same. (2013) Trans Tech Publications Switzerland.

A servo control system of dynamic target simulation device for aerial camera (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Advanced Design and Manufacturing Engineering, ADME 2012, August 16, 2012 - August 18, 2012, Taiyuan, China
作者: Ji Q.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

This article introduces a dynamic target simulation device to evaluate dynamic image quality of the aerial camera. The device simulated the positional relationship of the sky and ground in the laboratory when aerial camera flies at high altitude. And it can be used to inspect camera image quality of aerial camera flying at high altitude in laboratory. At a same time the article focuses on this servo control system of device building a control model and giving control strategy. The servo control system was proved stably and reliably after experimental verification. And it provides a strong guarantee for the test of the dynamic image. (2012) Trans Tech Publications Switzerland.

Color filtering method for CFA images based on gradient (EI CONFERENCE) 会议论文 OAI收割
International Conference on Communication Systems and Network Technologies, CSNT 2012, May 11, 2012 - May 13, 2012, Rajkot, Gujrat, India
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

Single-sensor digital cameras capture image by covering the sensor surface with a color filter array(CFA) such that each sensor pixel only samples one of three primary color values three color is R(red) G(green) and B(blue). To render a full-color image need an interpolation process commonly referred to as CFA demosaicking is required to estimate the other two contributions for producing a full-color image. But the noise in imaging sensors not only corrupts the color filter array at the same time introduces artifacts during the color interpolation step and influence quality of images. In order to acquire high quality full-color images adopt a sort of viable and effective interpolation algorithm based on gradient at the time of removing the noise reserve image border and detail information clearly. 2012 IEEE.

Method for improving transmission efficiency in 40Gbit/s system based on dispersion compensation (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Industrial Control and Electronics Engineering, ICICEE 2012, August 23, 2012 - August 25, 2012, Xi'an, China
Yu W.-J.; Wang R.-G.; Cheng P.; Zheng X.-F.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

In an effort to overcome the problem that the transmission efficiency is too low in 40Gbit/s system a method based on dispersion compensation is provided. Firstly the application background of 40Gbit/s system the key using technologies and the shortcomings and advantages of 40Gbit/s system are possessed. Secondly an application program of 40Gbit/s system based on dispersion compensation is given. At the same time this program is analyzed. Thirdly this program is compared with another program which has been widely used in 40Gbit/s system. Finally the compared results show that this program is able to improve the transmission efficiency apparently. 2012 IEEE.

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：48/0 | 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.

The study of heart monitor based Atmega128L (EI CONFERENCE) 会议论文 OAI收割
2nd World Congress on Computer Science and Information Engineering, CSIE 2011, June 17, 2011 - June 19, 2011, Changchun, China
作者: Chen J.; Zhang Y.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

This paper introduces a realtime system which can acquire process store and display heart sounds and electrocardiogram(ECG) of the human body at the same time. It is composed of superior microprocessor-Atmega128L large capacity Flash and the new type LCD. All hardwares adopt low power design and surface mounting package. The system do not affect the daily living and working of human being when it is used so it is suited for clinical and family monitoring. Springer-Verlag Berlin Heidelberg 2012.

Design of semi-physical simulation for small satellite by virtual display (EI CONFERENCE) 会议论文 OAI收割
2011 3rd International Conference on Mechanical and Electronics Engineering, ICMEE 2011, September 23, 2011 - September 25, 2011, Hefei, China
Xu K.; Lv Y.; Jin G.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

Semi-physical simulation of attitude control system is the more synthetically test and verify for designing of small satellite control system. It is an important means of small satellite development. However the results of current semi-physical simulation system have a lot of non-intuitive. Compare with the actual environment the simulation environment still has striking disparity. So the shortcomings affect precision of simulation. Based on the virtual display technology the group semi-physical simulation system has been constructed for attitude control of small satellite due to the combination with xPC real-time environment the simulation computer high-precision single-axis air-bearing turntable reaction wheel air thrust device fiber gyroscopes sensors synchronizer power subsystem and wireless devices virtual display computer etc. Semi-physical simulation achieved the visual simulation in orbit and tracked new information of virtual environment of space into real-time simulation computer. Simulation results show that the simulation system for real-time attitude and orbit position of small satellite semi-physical simulation has an excellent display effect. At the same time Real-time transfuse of orbit information provides a more accurate space environment simulation. The simulation system of small satellite attitude control to design and evaluate the more direct and convenient. (2012) Trans Tech Publications Switzerland.

Study on time registration method for photoelectric theodolite data fusion (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
Yang H.-T.; Gao H.-B.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

In range measurement theodolite and radar constitute a real-time tracking system at different sites to track the same target in the air and get useful information exactly and timely. As the optical theodolite and radar have different sampling frequency and measurement system the data is sent to the fusion center is asynchronous. This paper proposed a time registration method based on multi-sensor data using Wavelet neural network algorithm which not only better solved the basic problems of theodolite fusion tracking but also improve the efficiency of data fusion. Simulation experiment and comparison with other time registration method have shown the advantage of this method. 2012 IEEE.

Optimization analysis for radial support by finite elements method (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
作者: Wang Y.; Wang Y.; Wang Y.; Li C.; Wang Y.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

Primary mirror' surface figure is affected by supporting structure obviously. Especially for large-aperture telescope the surface figure is significant because of primary mirror' self-weight. For the requirement of the usage it's necessary to minimize the surface figure from self-weight by reasonable supporting scheme. The text optimized support point and force of radial support to minimize the surface figure by finite-element software. At the same time it studied the relationship between support point and counterweight to reduce the weight of support structure. At last it gave the optimal solution. (2012) Trans Tech Publications.