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In-plane load measuring technique for the strength test of MEMS micro-cantilever

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Chinese Science Bulletin 2006年第23期51卷 2819-2823页

作者： HUAN yong zhang Taihua yang Yemin State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of Sciences Beijing 100080 China

An in-plane load measuring technique is developed to perform the strength test of the micro-cantilever. Based on electromagnetism theorem, Micro UTM (Universal Testing Machine) was in-house made with the load range ±1 N and the displacement range ±300 μm. It applies an in-plane load on the free-end of the micro-cantilever. The load acts as a bending moment for the root of the cantilever, but as a torque for the anchor. The results show that for samples with different sizes the ultimate loads range from 1.3 to 69.8 mN and the calculated torque is ap-proximately proportional to the square of the bonding length. Two failure modes, fracture at the root of the cantilever and fracture at the anchor, are observed by micro examination to the debris, which indicates that there is a critical design to achieve the strength bal-ance between the cantilever and the anchor. The work demonstrates that Micro UTM is a powerful in-strument for the strength test of the micro-cantilever and similar micro-structures.

关键词：测试强度微旋臂机械学

THE LIMIT THEOREM FOR DEPENDENT RANDOM VARIABLES WITH APPLICATIONS TO AUTOREGRESSION MODELS

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Journal of Systems Science & Complexity 2011年第3期24卷 565-579页

作者： yong zhang Xiaoyun yang Zhishan DONG Dehui WANG College of Mathematics Jilin University (Qianwei Campus) Changchun 130012 China

This paper studies the autoregression models of order one, in a general time series setting that allows for weakly dependent innovations. Let {Xt} be a linear process defined by Xt =∑k=0^∞ψ kεt-k, where {ψk, k ≥ 0} is a sequence of real numbers and {εk, k = 0, ±1, ±2,...} is a sequence of random variables. Two results are proved in this paper. In the first result, assuming that {εk, k ≥ 1} is a sequence of asymptotically linear negative quadrant dependent （ALNQD） random variables, the authors find the limiting distributions of the least squares estimator and the associated regression t statistic. It is interesting that the limiting distributions are similar to the one found in earlier work under the assumption of i.i.d, innovations. In the second result the authors prove that the least squares estimator is not a strong consistency estimator of the autoregressive parameter a when {εk, k ≥ 1} is a sequence of negatively associated （NA） random variables, and ψ0 = 1, ψk = 0, k ≥ 1.

关键词： ALNQD autoregression models least squares estimator negatively associated unit root test.

A Novel Ephemeris Model for Martian Moons Incorporating Their Free Rotation

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Research in Astronomy and Astrophysics 2024年第11期24卷 181-191页

作者： yong-zhang yang Kai Huang Jian-Guo Yan Yu-Qiang Li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430070China

High-precision ephemerides not only support space missions,but can also be used to study the origin and future of celestial *** this paper,a coupled orbit-rotation dynamics model that fully takes into account the rotation of the Martian moons is *** and Deimos’rotations are first described by Eulerian rotational equations,and integrated simultaneously with the orbital motion *** and orientational parameters of Mars satellites were simultaneously obtained by numerical integration for the first *** order to compare the differences between our newly developed model and the one now used in the ephemerides,we first reproduced and simulated the current model using our own parameters,and then fit it to the Institut de Mécanique Céleste et de Calcul deséphémérides ephemerides using least-square *** adjustment test simulations show Phobos and Deimos’orbital differences between the refined model and the current model are no more than 300 m and125 m,*** orientation parameters are confirmed and the results are in good agreement with the International Astronomical Union ***,we simulated two perturbations(main asteroids and mutual torques)which were not included in our refined model,and find that their effects on the orbits are completely *** for the effect on rotation,we propose to take care of the role of mutual attraction in future models.

关键词： planets and satellites dynamical evolution and stability methods numerical celestial mechanics astrometry

Determination of the free lunar libration modes from ephemeris DE430

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Research in Astronomy and Astrophysics 2017年第12期17卷 89-94页

作者： yong-zhang yang Jin-Ling Li Jin-Song Ping Hideo Hanada Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China University of Chinese Academy of Sciences Beijing 100049China RISE Project National Astronomical Observatory of JapanOshu 0230861Japan

The Moon’s physical librations have been extensively studied, and elaborate researches have been developed for the purpose of deriving accurate modes of free librations. Our motivation comes from the Planetary and Lunar Ephemeris DE430 by JPL/NASA, which was created in April 2013,and is reported to be the most accurate lunar ephemeris today using the data from Gravity Recovery and Interior Laboratory（GRAIL）. Therefore, the residuals after fitting the model have reduced owing to improvement in the libration models, and the free librations embedded in the Euler angles have also improved. We use Fourier analysis to extract the approximate frequencies from DE430 and then a quadratic interpolation method is used to determine higher accuracy frequencies. With the frequencies,the linear least-squares fitting method is employed to fit the lunar physical librations to DE430. From this analysis we identified the three modes of free physical librations, and estimated the amplitudes as 1.471′′in longitude, 0.025′′in latitude and 8.19′′× 3.31′′for the wobble, with the respective periods of1056.16, 8806.9 and 27262.99 d. Since the free librations damp with time, they require recent excitation or a continuous stimulating mechanism in order to sustain.

关键词： Moon physical librations Fourier analysis least squares method

Influence of the layered Moon and Earth’s orientation on lunar rotation

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Research in Astronomy and Astrophysics 2020年第2期20卷 45-52页

作者： yong-zhang yang Jin-Song Ping Jian-Guo Yan Jin-Ling Li State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430070China Instituto de Astronomia y Ciencias Flanetarias de Atacama Universidad de AtacamaCopayapu 485Chile National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China

One of the most efficient ways to probe the lunar inner structure at present is through the study of its *** and range rate(Doppler) data between the Chang’E-3 lander and station on the Earth were collected from the beginning of the Chang’E-3 lunar mission in *** observation data,taken together with the existing lunar laser ranging data,provide a new approach to extend research on the Earth-Moon *** high precision of current observation data imposes exacting demands,making it necessary to include previously neglected *** this paper,motivated by progress of the Chinese lunar exploration project and to use its data in the near future,two lunar models:a one-layer model and a two-layer model with a fluid core,were applied to the rotational equations based on our implemented algorithm of the Moon’s *** was a difference of about 0.5′′in φ and ψ,but 0.2′′in θ between the two *** result confirms that stratification of the inner structure of the Moon can be inferred from rotation *** also added precise Earth rotation parameters in our model;the results show that this factor is negligible at present,due to the limited precision of the existing *** results will help us understand the rotational process clearly and build a more realistic Earth-Moon model when we combine Lunar Laser Ranging data with high precision radio data to fit lunar motion in the near future.

关键词： Moon rotation model numerical integration Earth orientation parameters

Fabrication of Graphene by Cleaving Graphite Chemically

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Chemical Research in Chinese Universities 2011年第4期27卷 547-549页

作者： ZHAO Shu-hua ZHAO Xiao-ting FAN Hou-gang yang Li-li zhang yong-jun yang Jing-hai Physics College of Jilin Normal University Siping 136000 P. R. China

Graphite was chemically cleaved to graphene by Billups Reaction,and the morphologies and microstructures of graphene were characterized by SEM,Raman and *** results show that the graphite was first functionalized by 1-iodododecane,which led to the cleavage of the graphene layer in the *** second decoration cleaved the graphite further and graphene was *** heights of the graphene layer were larger than 1 nm due to the organic decoration.

关键词： Graphene Graphite Chemical cleaving

Computation of the atmosphere-less light intensity curve during a total solar eclipse by using Lunar Reconnaissance Orbiter topography data and the DE430 astronomical ephemeris

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Research in Astronomy and Astrophysics 2021年第1期21卷 105-118页

作者： Yun-Bo Wang Jian-Guo Yan Mao Ye yong-zhang yang Fei Li Jean-Pierre Barriot State Key Laboratory of InformationEngineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Geodesy Observatory of Tahiti University of French PolynesiaBP 657098702 FaaTahitiFrench Polynesia Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

Observations of the sky irradiation intensity in the visible wavelengths during a solar eclipse permit to model the Sun diameter,a key number to constrain the internal structure of our *** this paper,we present an algorithm that takes advantage of the precise Moon topography from Lunar Reconnaissance Orbiter to compute,with a high resolution in time,the geometrical part(***-of-atmosphere,and for a given wavelength)of the sky irradiation at any given location on the Earth during these *** algorithm is also able to model the Baily’s *** give as an application the theoretical computation of the light curve corresponding to the solar eclipse observed at Lakeland(Queensland,North Australia)on 2012 November *** application to real data,with the introduction of atmospheric and instrumental passbands,will be considered in a forthcoming paper.

关键词： eclipse Moon Sun:fundamental parameters

When History Becomes A Standing Joke：Mo Yan＇s Reflection on China＇s Historical Changes Throughout the 20th Century

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Journal of Literature and Art Studies 2017年第7期7卷 783-791页

作者： zhang yong yang Fang Xi'an Jiaotong University Xi'an China

Since the end of the 20th century, Mo Yan has made an attempt to reflect on China＇s historical changes throughout the 20th century as a whole. Centered on such several novels as Big Breasts and Wide Hips, Life and Death Are Wearing Me Out and Frog, this paper explores the author＇s thinking of the interruption and repetition phenomena in China＇s 20th century history. Differing from viewing the history in a modem linear progressive perspective, Mo Yan regards the interruption of history as a sign of human degradation, which derives from the loss of folk history subjectivity. When history is treated rudely, its repetition will occur, and the one who treats history as laughingstocks will be written into history as part of a ＂farce＂.

关键词： Mo Yan the 20th century interruption of history repetition of history

Upper Large Deviations for Mixing Random Sequence

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Communications in Mathematical Research 2010年第3期26卷 219-229页

作者： zhang yong yang XIAO-YUN DONG ZHI-SHAN Wang De-hui College of Mathematics Jilin University Changchun 130012

In this article, we prove upper large deviations for the empirical measure generated by stationary mixing random sequence under some suitable assumptions and upper large deviations for the mixing random sequence.

关键词： mixing sequence empirical measure large deviation