中国科学院机构知识库网格系统: 检索

Coupling of quasi-localized and phonon modes in glasses at low frequency 期刊论文 OAI收割
CHINESE PHYSICS B, 2024, 卷号: 33, 期号: 5, 页码: 8
作者: Duan J(段军); Cai SL(蔡松林); Ding G(丁淦); Dai LH(戴兰宏); Jiang MQ(蒋敏强)

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收藏 | 浏览/下载：8/0 | 提交时间：2024/06/11

metallic glasses low-frequency vibrational modes plane wave boson peak 65.60.+a 62.20.D- 62.25.Jk

Combining complementary methods for implicitizing rational tensor product surfaces 期刊论文 OAI收割
COMPUTER-AIDED DESIGN, 2018, 卷号: 104, 页码: 100-112
作者: Shen, Li-Yong; Goldman, Ron

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收藏 | 浏览/下载：23/0 | 提交时间：2018/10/07

Base point Implicitization A-resultant Moving plane Resultant Extraneous factor

Characterization of Two Pollen Allergens of the London Plane Tree in Shanghai 期刊论文 OAI收割
IRANIAN JOURNAL OF ALLERGY ASTHMA AND IMMUNOLOGY, 2015, 卷号: 14, 期号: 2, 页码: 139-148
作者: Chen, Z; Yang, Y; Chen, XD; Wu, ZL; Li, SF

收藏 | 浏览/下载：39/0 | 提交时间：2015/07/22

London plane tree Mass spectrometry Pla a 1 Pla a 2 Platanus acerifolia Pollen allergen

Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer (EI CONFERENCE) 会议论文 OAI收割
作者: Lin G.-Y.

收藏 | 浏览/下载：38/0 | 提交时间：2013/03/25

Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution high spectral resolution and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating which make the anterior Wadsworth condition fulfilling each wavelength is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. 2012 Optical Society of America.

Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文 OAI收割
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：42/0 | 提交时间：2013/03/25

Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror semiconductor lasers as light source and CCD sensor as receiver. The system is smaller lighter and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

Improved method of target detection on optoelectronic hybrid joint transform correlator in cluttered scences (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
作者: Yang L.; Yang L.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

A classical joint transform correlator (JTC) usually yields large correlation sidelobes as well as a large correlation peak width strong zero-order peak and low diffraction efficiency which make the detection ability of JTC lower. To overcome these difficulties firstly a joint power spectrum (JPS) subtraction technique in Fourier plane was proposed where reference image power spectrum and object image power spectrum are subtracted from the JPS before inverse Fourier-transform operation it is obvious that the modified JPS removes the zero-order term. Secondly a fringe-adjusted filter (FAF) was presented to suppress sidelobes and noises. The modified JPS is multiplied by a FAF before the inverse Fourier-transform operation to obtain the cross-correlation peak. Computer simulations demonstrated the improved method can obviously remove zero-order diffraction and effectively suppress the sidelobes and noises compared with classic JTC and then improve the detection ability for JTC. Experimental results presented the sharp correlation peak and also confirmed the method effectiveness. (2012) Trans Tech Publications Switzerland.

Research on the torque characteristic of disc micromotor on axial magnetic field (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012, April 21, 2012 - April 23, 2012, Three Gorges, China
Liu B.

收藏 | 浏览/下载：53/0 | 提交时间：2013/03/25

In order to increase the electromagnetic torque density of micromotor with axial magnetic field numerical analysis of permanent magnetic field and electromagnetic torque were deduced and the key factors of increasing torque density of micromotor was obtained. The numerical analysis of three-dimensional magnetic field in air gap produced by spliced sector permanent magnetic poles is done and the way of improving flux density and permanent magnet use efficiency are given through investigating the influence of magnet thickness height of air gap and pole interval rate and other parameters to air gap flux density and leakage flux. Based on the test of axial magnetic field and torque characteristic of micromotor the analysis of micromotor magnetic field and calculation of torque are verified meanwhile using the plane stator with 0.7mm thickness assemble micromotor having minimum air gap height of 1mm and its torque constant up to 3.8mNm/A. 2012 IEEE.

Study on ultra-light secondary baffle for coaxial two-mirror telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Zhang L.; Zhang L.

收藏 | 浏览/下载：62/0 | 提交时间：2013/03/25

The coaxial two-mirror telescope consists of two mirrors facing each other. Classical two-mirror arrangements are Gregorian and Cassegrain. These systems are usually applied to space telescopes and often have optical baffles to prevent stray light from entering the focal plane. The optical baffles consist of concentric rings suspended between the secondary and the primary mirror. The secondary baffle for a large two-mirror optical system is designed and analyzed in this paper. According to mission of a telescope the structure should have high stiffness and high reliability and light weight. Compared with invar aluminum alloy and titanium alloy carbon fiber composite is currently the best material in terms of weight-to-strength ratio. It also has advantages of high temperature tolerance and low thermal expansion. So carbon fiber composite is chosen as material to meet requirements of the coaxial telescope. In this paper optimization method based on finite element analysis (FEA) is used for design the secondary baffle. Minimum weight of the baffle is chosen as an objective function. Thicknesses of former tube and vanes are chosen as variables. Analysis results show that the designed secondary baffle has maximum diameter of 180mm total length of 120mm and weighs 142g. And its fundamental frequency reaches 651Hz. Therefore the baffle has many advantages such as ultra-light weight high stiffness and dimensional stability etc. The optimization method and the baffle design can be helpful to other coaxial telescopes such as Cassegrain Gregorian and their subdivisions. 2012 IEEE.

Design and experimental research of a new type focus mechanism used in space-based telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Wang D.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

The position of focal plane will be changed because of temperature fluctuation and vacuum environment. In order to make the telescope work well positioning accuracy of the mechanism is 0.008mm. The performance satisfies the need of precision a focusing mechanism is needed. To majority of large space-based telescopes and the scheme design is reasonable and practicable. 2012 IEEE. the general way to do this would be to use a reflector which was located in the backfocal distance. One of typical schemes of this mechanism was introduced however because of the big axial size the mechanism can't be used when the size of the enclosure was limited. A new type of focusing mechanism was introduced which has such advantages of small size high accuracy and low mass. The design and test methods had been discussed. According to the results the repeatability positioning accuracy is 0.0025mm

Simulation test research of using the Ritchey-Common method for the detection of large flat mirror (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Frontiers of Advanced Materials and Engineering Technology, FAMET 2012, January 4, 2012 - January 5, 2012, Xiamen, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

In the detection of large flat mirror the Ritchey-Common test can achieve high accuracy measurement. A method which expands the compressed images due to Ritchey Angle and rotates the plane under test is presented achieve two sets of influence functions through this we can built two equations according to two different angular positions we can solve the equations by least squares method. Then through fitting the coefficients we can get the flat errors this paper describe the simulation test of the method in order to prove the feasibility and reliability of this method. (2012) Trans Tech Publications.