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Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

A meta-analysis of soil background N2O emissions from croplands in China shows variation among climatic zones 期刊论文 OAI收割
AGRICULTURE ECOSYSTEMS & ENVIRONMENT, 2018, 卷号: 267, 页码: 63-73
作者: Aliyu, Garba; Sanz-Cobena, Alberto

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收藏 | 浏览/下载：43/0 | 提交时间：2019/05/23

Background N2O emissions Background N2O emission rate Climatic zone Croplands Soil properties

Associations of Plasma Amino Acid and Acylcarnitine Profiles with Incident Reduced Glomerular Filtration Rate 期刊论文 OAI收割
CLINICAL JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY, 2018, 卷号: 13, 期号: 4, 页码: 560-568
作者: Wang, Feijie; Sun, Liang; Sun, Qi; Liang,Liming; Gao, Xianfu

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Adult Incidence Metabolomics risk factors acylcarnitine Cysteine Metabolome Amino Acids glomerular filtration rate Principal Component Analysis Follow-Up Studies Genetic Background Carnitine Chromatography Liquid Renal Insufficiency Chronic Mass Spectrometry Biomarkers Environmental Exposure Humans

Key features of new particle formation events at background sites in china and their influence on cloud condensation nuclei 期刊论文 iSwitch采集
Frontiers of environmental science & engineering, 2016, 卷号: 10, 期号: 5, 页码: 11
作者: Shen, Xiaojing; Sun, Junying; Zhang, Xiaoye; Zhang, Yangmei; Zhang, Lu

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New particle formation Regional background Cloud condensation nuclei Growth rate Formation rate

Research on infrared dim-point target detection and tracking under sea-sky-line complex background (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Dong Y.-X.; Zhang H.-B.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：111/0 | 提交时间：2013/03/25

Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties.There are some traditional point target detection algorithms such as adaptive background prediction detecting method. When background has dispersion-decreasing structure the traditional target detection algorithms would be more useful. But when the background has large gray gradient such as sea-sky-line sea waves etc.The bigger false-alarm rate will be taken in these local area.It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature in our opinion from the perspective of mathematics the detection of dim-point targets in image is about singular function analysis.And from the perspective image processing analysis the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection its essence is a separation of target and background of different singularity characteristics.The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore the purpose of the image preprocessing is to reduce the effects from noise also to raise the SNR of image and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics the median filter is used to eliminate noise improve signal-to-noise ratio then the multi-point multi-storey vertical Sobel algorithm will be used to detect the sea-sky-line so that we can segment sea and sky in the image. Finally using centroid tracking method to capture and trace target. This method has been successfully used to trace target under the sea-sky complex background. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Awareness of the background rate of sudden cardiac death during mass immunization with pandemic h1n1 influenza vaccines increases the intended vaccination rate 期刊论文 iSwitch采集
Preventive medicine, 2010, 卷号: 51, 期号: 5, 页码: 445-446
作者: Wang, Youxin; Xiao, Zhongxin; Wang, Wei

收藏 | 浏览/下载：13/0 | 提交时间：2019/05/10

Background rate Sudden cardiac death Pandemic h1n1 influenza vaccines The intended vaccination rate

Design of real-time small target detection system for infrared image based on FPGA (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Optics, Photonics and Energy Engineering, OPEE 2010, May 10, 2010 - May 11, 2010, Wuhan, China
作者: Liu J.; Sun Q.; Wang J.; Ye X.; Xu H.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

A simple detection measurement is developed for realtime small target detection in infrared background which can be easily available on FPGA. Basing on the difference between target and background a predictive background is generated via restraining the infrared background with median filter and then global threshold segmentation is used to residual image for further processing. Taking advantage of the relationship of targets in frames a comprehensive analysis of residual image is made and then the precise position of target is got by removing pseudo-objectives. Experiment results show that the method is simple to apply to hardware system improve the system's false alarm rate and meet the requirements of practical engineering. 2010 IEEE.

Design of CAN bus application layer protocol for aerocraft control system (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Industrial Mechatronics and Automation, ICIMA 2010, May 30, 2010 - May 31, 2010, Wuhan, China
作者: Zhang Y.; Zhang H.; Zhang H.; Zhang W.; Zhang W.

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A special Controller Area Network (CAN) bus application layer protocol is designed for the highly reliable communication of microcomputer-based systems in aerocraft control system by analyzing the practical time sequence of data transmission data priority data type and data function etc in this paper. Identifier distribution data storage form data type data exchange method and fault handling mechanism of the application layer protocol are specified in detail in the background of a real aerocraft control system. At last a simulation platform based on CAN bus for aerocraft control system is built to validate the design. Experimental results show that this application layer protocol meets the requirements of data transmission reliability real-time and high efficiency. The bus load rate is low and there is great room for expansion. 2010 IEEE.

Research on tracking approach to low-flying weak small target near the sea (EI CONFERENCE) 会议论文 OAI收割
ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China
作者: Xue X.-C.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

Automatic target detection is very difficult in complicate background of sea and sky because of the clutter caused by waves and clouds nearby the sea-level line. In this paper in view of the low-flying target near the sea is always above the sea-level line we can first locate the sea-level line and neglect the image data beneath the sea-level line. Thus the noise under the sea-level line can be suppressed and the executive time of target segmentation is also much reduced. A new method is proposed which first uses neighborhood averaging method to suppress background and enhance targets so as to increase SNR and then uses the multi-point multi-layer vertical Sobel operator combined with linear least squares fitting to locate the sea-level line lastly uses the centroid tracking algorithm to detect and track the target. In the experiment high frame rate and high-resolution digital CCD camera and high performance DSP are applied. Experimental results show that this method can efficiently locate the sea-level line on various conditions of lower contrast and eliminate the negative impact of the clutter caused by waves and clouds and capture and track target real-timely and accurately.

Monte Carlo simulation of the BEPC II/BESIII backgrounds - Touschek effect 期刊论文 OAI收割
HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION, 2006, 卷号: 30, 期号: 5, 页码: 449-453
作者: Jin DP(金大鹏); Guo YN(过雅南); Wang YF(王艳凤); Wu LH(伍灵慧); Liu ZA(刘振安)

收藏 | 浏览/下载：26/0 | 提交时间：2016/06/28

Touschek effect single wire counting rate radiation dose background