中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共7条，第1-7条

帮助

条数/页：排序方式：
	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 \| 收藏 \| 浏览/下载：48/0 \| 提交时间：2022/02/08 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 NOT operation on Majorana qubits with mobilizable solitons in an extended Su-Schrieffer-Heeger model 期刊论文 OAI收割 NEW JOURNAL OF PHYSICS, 2015, 卷号: 17, 期号: 0, 页码: 13017 作者: Xiong, Y; Tong, PQ 收藏 \| 浏览/下载：24/0 \| 提交时间：2016/11/21 Majorana fermion soliton bound state Not operation
	Optimal multiresolution dynamic models generation based on triangle importance (EI CONFERENCE) 会议论文 OAI收割 2nd International Conference on Image Analysis and Signal Processing, IASP'2010, April 12, 2010 - April 14, 2010, Xiamen, China 作者: Zhao J.; Zhang S. 收藏 \| 浏览/下载：20/0 \| 提交时间：2013/03/25 In this paper we propose an efficient method to generate optimal multiresolution dynamic models. By the method we define the triangle importance degree as a weight parameter to be embedded to the edge contraction cost so the new metric can not only measure distance error but also reflect geometric variation of local areas. A deformation degree weight is appended to the aggregated edge contraction cost for the whole animation thus sharp features on areas with large deformation can be preserved. In addition a process of mesh optimization and validity check can further alleviate the geometric distortion of the approximations. Our approach is efficient in operation easy for implementation and as a result high quality of dynamic approximations with well-preserved fine details can be generated at any given frame. 2010 IEEE.
	Electromagnetic radiation test of power driver module in optical tracking system and electromagnetic compatibility (EI CONFERENCE) 会议论文 OAI收割 2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China 作者: Yu H. 收藏 \| 浏览/下载：31/0 \| 提交时间：2013/03/25 In order to solve the conductive ring module's interference problems measured the electromagnetic radiation of Power drive module and used test results analysis the electromagnetic compatibility of the conductive ring identified and implemented appropriate EMC (electromagnetic compatibility) measures. When optical tracking system working test equipment can not be fixed. Therefore from the electromagnetic radiation theory the paper analyzed the electromagnetic radiation of the power drive module. From it determine the EMC pre-compliance test method for electromagnetic radiation of power drive module. Based on Test results calculate the interference voltage of wire in Conductive ring and then determine the corresponding EMC method. The results show that when The power drive module Radiate Electromagnetic waves wires would coupled common mode interference voltage its frequency is 3MHz amplitude is about 10V it would interfered the operation of sensor. By reducing the area of ground loops used shielded cables final rule out the interference. 2010 IEEE.
	Correction method for detection of the frequencies of railway fsk signals (EI CONFERENCE) 会议论文 OAI收割 2008 9th International Conference on Signal Processing, ICSP 2008, October 26, 2008 - October 29, 2008, Beijing, China 作者: Yu J. 收藏 \| 浏览/下载：63/0 \| 提交时间：2013/03/25 In order to acquire the information of railway binary frequency-shift keying signals which include upper/down side frequencies and base low-frequency with high-accuracy a novel frequency detection algorithm for France UM-71 system is proposed. Combining fast Fourier transform with the ratio correction method the carrier frequency and the base frequency are obtained. Furthermore the hardware consumption has been decreased. And it possesses the advantage of simple algorithm and fast operation speed. Comparing with the detection of the base frequency the upper/down side frequency of railway signal is more difficult. Based on spectrum analysis and the spectrum correction a new method which adopts the sliding window is put forward in this paper. The absolute differences between the upper side frequencies and the down side frequencies obtained are regarded as the criterion for judgment. Then the set of data in which the maximum absolute value is is to be the result of the upper/down side frequency. Because the sliding window will go through every stage when the upper/down side frequency changes therefore it is not sensitive enough to the position of data which need to be transformed. Using the method mentioned above the experiment results show that the accuracy requirement of the side frequency is satisfied well. 2008 IEEE.
	The spectral feature analysis of semiconductor thin disk laser (EI CONFERENCE) 会议论文 OAI收割 Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China 作者: Li J.; Wang L.-J.; Wang L.-J.; Ning Y.-Q.; Li J. 收藏 \| 浏览/下载：23/0 \| 提交时间：2013/03/25 The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of semiconductor disk laser and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperature. We can see that: with increasing pump power the thermal effects of the gain material becomes seriously and causes the saturation of carrier lifetime so the electron-hole pair created in the absorbtion layer have no enough time to rate to one of the wells and the non-radiative recombination happens in the barrier. When the thermal effects becomes stronger the chip will not lasing. This phenomenon is from the smaller energy offset between barrier and quantum well. We optimize the original structure design and experimental technology. A non-absorbing AlGaAs layer who is transparent to the pumping and laser wavelength is added to confine the carriers in the quantum wells. At the same time a DBR with double reflecting band is induced to improve the absorbing efficiency of the pumping light. The single QW is replaced by the three narrow QWs This three QWs structure can add the quantum state of QW increase the recombination probability of carriers in the QWs and reduce the heat effect. The chemical etch equipment is also improved to control the surface unevenness to be within 50 nm.
	Low power frame buffer pixel circuits for LCoS microdisplays (EI CONFERENCE) 会议论文 OAI收割 13th International Display Workshops, IDW '06, December 6, 2006 - December 6, 2006, Otsu, Japan Song Y.; Ling Z. 收藏 \| 浏览/下载：14/0 \| 提交时间：2013/03/25 In the frame buffer pixel circuits extra power was dissipated to implement the data transfer operation. Extra power dissipation can not only increase power but also decrease the device reliability. One method to deal with it at pixel level is needed. In this novel pixel circuit one PMOS transistor acts as a simple analog comparator in order to determine whether the discharging by comparing the current pixel voltage and the next frame data voltage.