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Numerical calculation of N-periodic wave solutions to coupled KdV-Toda-type equations 期刊论文 OAI收割
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 2021, 卷号: 477, 期号: 2245, 页码: 21
作者: Zhang, Yingnan; Hu, Xingbiao; Sun, Jianqing

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收藏 | 浏览/下载：19/0 | 提交时间：2021/04/26

N-periodic wave solution coupled KdV-Toda-type equation Riemann's -function the direct method

Reentry guidance based on parametric optimization (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Mechatronics and Control Engineering, ICMCE 2012, November 29, 2012 - November 30, 2012, Guangzhou, China
作者: Li D.

收藏 | 浏览/下载：161/0 | 提交时间：2013/03/25

This paper presents a parametric optimization approach to solve reentry guidance. Due to the various constraints imposed on the trajectory original guidance problem can be converted into an optimal control problem with a merit function to be minimized. Direct implementation of method of variation and is too complex to get a reasonable result while a numerical parametric optimization approach is feasible and efficient if we choose appropriate control variables as the optimization parameters and effective optimization algorithm. A simulation of the approach is performed to show its validity on reentry guidance problem: as the value of merit function converges to acceptable threshold all constraints are hold. (2013) Trans Tech Publications Switzerland.

LABTM control system based on FPGA (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Mechatronics and Applied Mechanics, ICMAM 2012, December 8, 2012 - December 9, 2012, Taiwan
作者: Wang Y.; Yu P.; Yu P.; Wang Y.; Wang Y.

收藏 | 浏览/下载：152/0 | 提交时间：2013/03/25

This paper presents the digital PI control method for design and simulation of a high precision limited angle brushless torque motor control system in Field Programmable Gate Array device (FPGA). The direct drive structures which are widely applied in many servo control fields. Matlab Xilinx System GeneratorR toolbox based on Fixed-Point Arithmetic is used to design the digital PI controller using DSP architecture plot the responses of the control system and generate the VHDL source code. The control system model consists of a digital PI a real LABTM and a real absolute Inductosyn encoder to rpm and position blocks. Through loading generated codes in process of the simulation that built by the digital discrete model it is verified that the rising time of current loop is only 1.2ms and rate loop is 8ms overshoot is rarely 4.2%. Finally the comprehensive positioning accuracy of system can reach up to 5 arc sec and the rate jitter achieves 5% with the 4 arc sec accuracy absolute Inductosyn. (2013) Trans Tech Publications Switzerland.

Fabrication of high-efficiency ultraviolet blazed gratings by use of direct Ar2-CHF3 ion-beam etching through a rectangular photoresist mask (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, May 24, 2011 - May 26, 2011, Beijing, China
Tan X.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

In ultraviolet spectroscopy groove irregularity and surface roughness of nanometer magnitude can cause a significant loss of diffraction efficiency. Therefore there is a constant need to improve the diffraction efficiency. A blazed grating can concentrate most of the light intensity into a desired diffraction order it is important to control the groove shape precisely so it is the optimum choice among gratings of different kinds of profile. As the operating wavelength of most UV spectral applications is less than 200 nm especially the blaze angle and the apical angle. We have presented a direct shaping method to fabricate EUV blazed gratings by using an ion-beam mixture of Ar+ and CHF2 +to etch K9 glass with a rectangular photoresist mask. With this method the required blaze angle is small we have succeeded in fabricating well-shaped UV blazed gratings with a 1200 line/mm groove density and 8.54 blaze angles and 1200 line/mm groove density and 11.68 blaze angles and the metrical efficiency is about 81% and 78%. The good performance of the gratings was verified by diffraction efficiency measurements. When one uses the etching model the conditions on the ion-beam grazing incident angle and the CHF3partial pressure should be noted. Besides since the etched groove shape depends on the aspect ratio of the photoresist mask ridge if we wish to fabricate larger gratings with this method we must improve the uniformity of the photoresist mask before ion-beam etching. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Combination of skip-flat test with Ritchey-Common test for the large rectangular flat (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: Zhang L.; Xuan B.; Zhang L.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

The Skip-Flat test and Ritchey-Common test are the well-known methods for large flat mirrors measurement. This paper describes the theories of two methods. The combination of the Skip-Flat test with Ritchey-Common test is proposed. Simulations and experiments of the combination method for testing the large rectangular flat of high aspect ratio are shown. The results of the combination test and direct measurement are presented. In comparison of the methods the combination test is in good agreement with the direct measurement. 2010 Copyright SPIE - The International Society for Optical Engineering.

The implementation of parachute jump commanding and simulation training system (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
作者: Li Y.; Li Y.; Li Y.; Li Y.; Cui S.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

In order to improve the method of training the commander secondly thirdly Finally the aerial instructor we adopted Vega to develop the aerial instructor federate with the models we build with Creator on MFC at Visual C++6.0 platform we implement the commander federate we interlink the federate that we implemented above with RTI back parachute commander the guarantee unit federate realize a cooperated parachute jump training system. Through lots of experiments and we compare the training system experiment result with the computes data the guarantee unit and the aerial broadcaster the back parachute commander federate and the aerial broadcaster federate on MFC at VC++6.0 we use the compare result to direct the trainee. This system makes the parachute jump command training more effective in this paper more safety we used Vega shorten training cycle Creator lower costs and weather protected. 2010 IEEE. and RTI implement the Parachute Jump Commanding And Simulation System to simulate the parachute jump commanding process. In this system firstly we used Creator build the 3D models that we need in the system

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.

Dynamic data fixing for IR target radiation characteristics (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
Lihua C.; Juan C.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

The main methods to measure the target IR features are the following two ways: test and then measurement or theoretical and simulation calculation. The former is direct measurement so the results are more accurate but the test is costly and complicated so that it is limited in the application. Theoretical and simulation calculation are widely used in the target IR radiation calibration. Here we give the basic configuration of the calibration platform for measuring the IR radiation of the large area low temperature blackbody source and discuss the calibration flowchart and key technologies for atmospheric transmission correction. The dynamic data are analyzed in real time to determine the IR radiation features in the data fusion subsystem and the experimental results show that the calibration method is feasible and practical. 2010 IEEE.

Real-time defogging processing of aerial images (EI CONFERENCE) 会议论文 OAI收割
2010 6th International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2010, September 23, 2010 - September 25, 2010, Chengdu, China
作者: Liu G.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

A real-time image defogging processing method based on FPGA is proposed to increase low-contrast of the aerial images in foggy vision conditions. According to the high similarity of the contiguous frame histogram in video image the histogram equalization algorithm is improved to enhance the image contrast. The median filter algorithm is used to eliminate the noise of the image. The experimental results demonstrate that the method can efficiently enhance the contrast strengthen the detail and clarify definition for the fog-degraded aerial images. The visibility limit of the images has been increased to a time above. Simultaneously the method satisfies the real-time processing requirement of aerial video images which has direct applications to the problem of poor visibility conditions. 2010 IEEE.

Alignment of off-axis asphere and compensator with four poles (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Li J.; Chen Y.; Li J.; Li J.; Wang P.

收藏 | 浏览/下载：58/0 | 提交时间：2013/03/25

Aspheres are utilized widely thanks to the development of optical design manufacture and testing. Compensators are usually necessary when aspheres are under test. The alignment of aspheres and their compensators is a risk because it's tough to check whether the compensators work in right way. A new method of alignment with four poles is put forward in this paper. Optical interval error can be tight while it is quite important due to direct influence on central curvature conic constant and high order coefficients of aspherical surface. A modified on-axis Foucault apparatus is set up since it makes the optical axis visible and helps to control the error of off-axis amount. Some small holes are drilled in the metallic cell of the compensator so that the ends of poles can be stably relied on in order to increase operational repeatability. The method has been carried out practically and it matches the measurement result given by a set of theodolites. 2009 SPIE.