中国科学院机构知识库网格系统: 检索

On theory and methods for advanced detonation-driven hypervelocity shock tunnels 期刊论文 OAI收割
NATIONAL SCIENCE REVIEW, 2020, 卷号: 7, 期号: 7, 页码: 1198-1207
作者: Jiang ZL(姜宗林); Li JP(李进平); Hu ZM(胡宗民); Liu YF(刘云峰); Yu HR(俞鸿儒)

|

收藏 | 浏览/下载：38/0 | 提交时间：2020/11/30

hypervelocity shock tunnel detonation driver flight condition tailored condition test facilities

新疆近地表空气干湿时空变化特征及其影响因素 学位论文 OAI收割
北京: 中国科学院大学, 2019
作者: 陈迪桃

|

收藏 | 浏览/下载：74/0 | 提交时间：2021/12/10

新疆干湿变化特征相对湿度 Mann-Kendall 趋势检验法影响因素 Xinjiang Variation characteristics of wet-dry condition Relative humidity Mann-Kendall trend test Influencing factors

环境因素对步进摩擦系数的影响 期刊论文 OAI收割
摩擦学学报, 2011, 卷号: 31, 期号: 2, 页码: 114-118
贾利晓; 张永振; 牛永平; 杜三明; 李健

收藏 | 浏览/下载：30/0 | 提交时间：2012/09/24

环境因素配副材料试验条件摩擦系数 environmental factor material of frictional couple test condition friction coefficient

The design of chisel-edge ruling tool for diffraction gratings (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
作者: Zhang F.; Zhang F.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

The process of parameters design on chisel-edge ruling tool of diffraction grating which is inefficient and highly costive needs plenty ruling experience came from a series of ruling test to optimize and design it. In order to reduce the choosing range of experiential design parameters on chisel-edge grating ruling tool to improve efficiency and to reduce costs this paper summarize the experimental results of several gratings ruling process for the experiential design on parameters of chisel-edge ruling tool. Provide the specific parameters choosing range as follows: that the blaze angle and directional angle difference in less than 3 the bottom angle and apex angle difference in less than 5. Apex angle larger than the groove bottom angle in conventional grating while apex angle smaller than the bottom angle in echelle grating and the directional angle smaller than blaze angle in both condition. 2011 IEEE.

The imaging system design of three-line LMCCD mapping camera (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
作者: Zhao Y.; Yu D.; Yu D.; Zhao Y.; Zhao Y.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

In this paper the SNR tested in laboratory is better than 95 under typical working condition(the solar incidence degree is 30 the temperature of the focal plane module is controlled under 30 in a working period of 15 minutes. All of these results can satisfy the requirements about the synchronous photography the authors introduced the theory about LMCCD (line-matrix CCD) mapping camera firstly. On top of the introduction were consists of the imaging system of LMCCD mapping camera. Secondly the photography interval of line-matrix CCD of the nadir camera can satisfy the butter requirements of LMCCD focal plane module the reflectivity of the earth's surface is 0.3) of each CCD image the temperature control of focal plane module and SNR some pivotal designs which were Introduced about the imaging system Which give the guarantee of precision for satellite photogrammetry. 2011 SPIE. such as the design of focal plane module the video signal's procession the controller's design of the imaging system synchronous photography about forward and nadir and backward camera and the nadir camera of line-matrix CCD. At last the test results of LMCCD mapping camera imaging system were introduced. The results as following: the precision of synchronous photography about forward and nadir and backward camera is better than 4 ns and the nadir camera of line-matrix CCD is better than 4 ns too

Experimental study of erosion threshold of reconstituted sediments 会议论文 OAI收割
30th International Conference on Ocean, Offshore and Arctic Engineering, Rotterdam, NETHERLANDS, JUN 19-24, 2011
作者: Ye ZH; Cheng L; Zang ZP(臧志鹏)

收藏 | 浏览/下载：28/0 | 提交时间：2013/02/26

Arctic engineering Erosion Mixtures Sedimentology Shear stress Coarse particles Cohesive sediments Equilibrium modes Erosion characteristics Erosion thresholds Experimental studies Mass content Mud weights Natural sediments Predicting models Research efforts Seabed sediments Test condition Testing facility

Study of three-mode parametric instability (EI CONFERENCE) 会议论文 OAI收割
8th Edoardo Amaldi Conference on Gravitational Waves, June 21, 2009 - June 26, 2009, New York, NY, United states
Liang F.; Zhao C.; Gras S.; Ju L.; Blair G.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

The effect of parametric instability in advanced interferometric gravitational wave detectors is a potential problem for their proper operation. Great efforts have been made to study the onset of parametric instabilities and to find ways to control them. Here we present an experimental design for studying parametric instability in a 72 m cavity with suspended high quality fused silica mirrors. With 5 W input power and 20 kW circulation power inside the cavity it is predicted that parametric instability will occur. The resonant condition of parametric instability can be met by thermally tuning the radius of curvature of a test mass. We will present simulation results of parametric gains for different radii of curvature of a test mass. The simulation results will provide the basis for designing the thermal tuning and observation parametric instability experiments. This will provide a test bed for studying parametric instability and its control for next generation detectors. 2010 IOP Publishing Ltd.

Modulation transfer function measurement of sampled imaging systems in field test (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Yang L.; Zhang J.; Zhang J.; Zhang J.; Wang J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

A digital mirror device (DMD) based light projector was developed as the target generator in modulation transfer function (MTF) measurement. In order to overcome the sampling-scene phase effect in MTF measurement of sampled imaging systems a method using random targets is introduced to yield a phase-averaged MTF. The main potential problem of implementing this method is the fact that the stationary assumption of the random targets may be vitiated in practical measurement especially in field test due to the ill condition. We provide an efficient model-independent way of analyzing and isolating the spectral contents arising from these additional contributions to MTF measurement. Algorithms with adaptive parameter selection were also developed for spectral estimation of the test image in order to overcome the challenge brought by the size limit of the test matrices for one certain field of view derived from the isoplantic region. The MTF measurement of a CCD video imager is used to demonstrate the measurement technique and illustrate the benefits over other methods. In order to validate the results comparisons have been made between MTF measurements of imager implemented using this method and bar target direct measurements. 2010 Copyright SPIE - The International Society for Optical Engineering.

Design and analysis of power system of micro-electromechanical actuator (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 J.; Zhang J.; Zhang J.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

In order to apply the electromechanical actuator to tactical mini-missiles maximum rotational speed of output shafts is greater than 250/s. Test results basically correspond to the requirement of technical indexes. It is proved that this analysis and design method is congruent with the design of micro-electromechanical actuators this paper researches on the key technology such as load-bearing ability the system bandwidth can reach 25.3Hz on the condition of no load and 23.4Hz on the condition of load thus the method is feasible. 2010 IEEE. rapidity and miniaturization of the micro-electromechanical actuator power system based on the ball screw. First according to specific technical indexes the power electromechanical time constant and the size of the motors are screened originally through theoretical analysis. Finally based on the characteristics of ball screw transmission load locus of the micro-electromechanical actuator dynamic system is theoretically analyzed and the optimum speed ratio is determined through parameter optimization. The results of the double closed loop controlled test on the principle prototype show: the system can operate normally with 2.5N.m hinge moment

Intelligent MRTD testing for thermal imaging system using ANN (EI CONFERENCE) 会议论文 OAI收割
ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
Sun J.; Ma D.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

The Minimum Resolvable Temperature Difference (MRTD) is the most widely accepted figure for describing the performance of a thermal imaging system. Many models have been proposed to predict it. The MRTD testing is a psychophysical task for which biases are unavoidable. It requires laboratory conditions such as normal air condition and a constant temperature. It also needs expensive measuring equipments and takes a considerable period of time. Especially when measuring imagers of the same type the test is time consuming. So an automated and intelligent measurement method should be discussed. This paper adopts the concept of automated MRTD testing using boundary contour system and fuzzy ARTMAP but uses different methods. It describes an Automated MRTD Testing procedure basing on Back-Propagation Network. Firstly we use frame grabber to capture the 4-bar target image data. Then according to image gray scale we segment the image to get 4-bar place and extract feature vector representing the image characteristic and human detection ability. These feature sets along with known target visibility are used to train the ANN (Artificial Neural Networks). Actually it is a nonlinear classification (of input dimensions) of the image series using ANN. Our task is to justify if image is resolvable or uncertainty. Then the trained ANN will emulate observer performance in determining MRTD. This method can reduce the uncertainties between observers and long time dependent factors by standardization. This paper will introduce the feature extraction algorithm demonstrate the feasibility of the whole process and give the accuracy of MRTD measurement.