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geometric analysis of Singularity for Single-Gimbal Control Moment Gyro Systems

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Chinese Journal of Aeronautics 2005年第4期18卷 295-303页

作者：汤亮徐世杰 School of Astronautics Beijing University of Aeronautics and Astronautics Beijing 100083 China

This research is focused on the singularity analysis for single-gimbal control moment gyros systems （SCMGs） which include two types, with constant speed （CSCMG） or variable speed （VSCMG） rotors. Through angular momentum hypersurfaces of singular states, the passable and impassable singular points are discriminated easily, meanwhile the information about how much the angular momentum workspace as well as the steering capability available is provided directly. It is obvious that the null motions of steering laws are more effective for the five pyramid configuration（FPC） than for the pyramid configuration（PC） from the singular plots. The possible degenerate hyperbolic singular points of the preceding configurations are calculated and the distinctness of them is denoted by the Gaussian curvature. Furthermore, failure problems to steer integrated power and attitude control system （IPACS） are also analyzed. A sufficient condition of choosing configurations of VSCMGs to guarantee the IPACS steering is given. The angular momentum envelops of VSCMGs, in a given energy and a limited range of rotor speeds, are plotted. The connection and distinctness between CSCMGs and VSCMGs are obtained from the point of view of envelops.

关键词： attitude control single-gimbal control moment gyros singularity geometric analysis angular momentum hypersurfaces store energy

Quantum System Schmidt Decomposition and Its geometric analysis

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Quantum System Schmidt Decomposition and Its Geometric Analy...

Revisiting the ionic diffusion mechanism in Li_(3)PS_(4) via the joint usage of geometrical analysis and bond valence method

第二十七届中国控制会议

作者： Cong Shuang,Feng Xianyong Dept.of Automation,University of Science & Technology of China,Hefei 230027,P.R.China

Quantum entangled state and some common methods to measure entanglement are introduced,and Schmidt decomposition of 2-qubit quantum state and the method to identify the entangled state are induced.A method to calculate the degree of entanglement is also given,which is obtained very easily by using the Schmidt *** example about NMR quantum computation is discussed to illustrate the application of the Schmidt *** evolution of the state of sub-system is described by using the Bloch vector,which demonstrates the geometric prospect of quantum system.

关键词： The Schmidt decomposition Quantum computation geometric analysis The Bloch vector

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Journal of Materiomics 2019年第4期5卷 688-695页

作者： Li Pan Liwen Zhang Anjiang Ye Shuting Chi Zheyi Zou Bing He Lanli Chen Qian Zhao Da Wang Siqi Shi School of Materials Science and Engineering Shanghai UniversityShanghai200444China School of Computer Engineering and Science Shanghai UniversityShanghai200444China School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi435003China Materials Genome Institute Shanghai UniversityShanghai200444China

Inorganic solid electrolytes have obvious advantages on safety and electrochemical stability compared to organic liquid electrolytes,but the advance on high ionic conductivity of typical electrolytes is still *** the first-principles calculation in the ion migration simulation is an important strategy to develop high-performance solid electrolyte,the process is very ***,we propose an effective method by combining the geometrical analysis and bond valance sum calculation to obtain an approximate minimum energy path preliminarily,in parallel to pave the way for the interoperability of low-precision and high-precision ion transport *** a promising electrolyte Li_(3)PS_(4) as an example,we revisit its Li-ionic transport *** calculated Li-ion pathways and the activation energies(the corresponding values:1.09 eV vs.0.88 eV vs.0.86 eV)in γ-,β- and α-Li_(3)PS_(4) are consistent with the ones obtained from the first-principles *** variations of the position of P-ions lead the rearrangement of the host PS_(4) tetrahedron,affecting the diffusion positions of Li-ions and further enabling high Li^(+) conductivity in β-Li_(3)PS_(4).

关键词： Solid electrolyte Conduction pathway Crystal structure analysis geometric analysis Bond valence method

Design and analysis of bidirectional deployable parabolic cylindrical antenna

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2014年第2期15卷 83-96页

作者： Tian YU Fu-ling GUAN Lu DAI College of Civil Engineering and Architecture Zhejiang University Hangzhou 310058 China

A bidirectional deployable parabolic cylindrical reflector for an L-band synthetic aperture radar is presented in this study, in which a self-deployed antenna with low weight was designed. The antenna consists of four curved surfaces formed from thin sheets of composite materials connected by hinges along the edges, and the reflective surface is provided by the front surface. The edge profiles of connecting lines were obtained through geometric analysis. A scaled model, including design and manufac- ture, was demonstrated to validate the process from the folded state to the fully deployed state. The non-contact synchronous vision measuring method was used to test the basic frequency of the scaled model, and the test results gave the verification of the analyses. Compared with the existing unidirectional deployable antenna, this new type of bidirectional deployable antenna can be applied to larger-size antennas and has better performance because the glass-woven tape connections were substituted with more reliable hinges. Static, modal, harmonic response, and transient response analyses of the full-sized reflector structure were mod- eled with the commercial finite element （FE） package ABAQUS. The modeling techniques were developed to predict the struc- tural dynamic behavior of the reflector and the results showed that the first natural frequency was 0.865 Hz, and the reflector structure had good stiffness in three directions. This proposed structure has very high stiffness-to-mass ratio because of its hollow solid construction. A preliminary simulation of radiation properties of the parabolic cylindrical antenna, fed by an off-set linear feed horn array, was conducted to obtain the radiation pattern of the feed and the reflector.

关键词： Parabolic cylindrical antenna geometric analysis Deploying and folding process Frequency test Structuralanalysis Radiation property

Laminated Polymer Solar Cells with PEDOT：PSS Film as Anode

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Chinese Physics Letters 2014年第2期31卷 153-156页

作者：侯腾梁春军张福俊何志群孙凯 Key Laboratory of Luminescence and Optical Information Institute of Optoelectronic Technology Beijing Jiaotong University Beijing 100044

A prefabricated conductive polymer film of polymer poly（3,4-ethylenedioxy-thiophene）：poly （styrene-sulfonate）（PEDOT：PSS） is developed and is used as the anode in an inverted polymer solar cell （PSC） through a lamination process. The geometry structure of the PSC is indium tin oxide/interface layer/P3HT：PCBM/PEDOT：PSS. The PEDOT：PSS electrode is 5 μm and the sheet resistance is 10Ω/sq. The device fabrication process is vacuum-free and extremely simple. Lithium carbonate （Li2CO3） and cesium carbonate （Cs2C03） are used as the cathode interface layers, respectively, and the result shows that Li2CO3 can enhance the open-circuit voltage （Voc） and fill factor distinctly, and the power conversion efficiency （PCE） can reach 2.1%.

关键词： SOLAR cells LAMINATED plastics POLYMER films geometric analysis SURFACE chemistry ENERGY conversion

geometric Proof of Riemann Conjecture

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Advances in Pure Mathematics 2021年第9期11卷 334-345页

作者： Chuanmiao Chen School of Mathematics and Statistics Central South University Changsha China College of Mathematics and Statistics Hunan Normal University Changsha China

This paper proves Riemann conjecture (RH), i.e., that all the zeros in critical region of Riemann ξ -function lie on symmetric line σ =1/2 . Its proof is based on two important properties: the symmetry and alternative oscillation for ξ = u + iv . Denote . Riemann proved that u is real and v ≡ 0 for β =0 (the symmetry). We prove that the zeros of u and v for β > 0 are alternative, so u (t,0) is the single peak. A geometric model was proposed. is called the root-interval of u (t,β) , if |u| > 0 is inside Ij and u = 0 is at its two ends. If |u (t,β)| has only one peak on each Ij, which is called the single peak, else called multiple peaks (it will be proved that the multiple peaks do not exist). The important expressions of u and v for β > 0 were derived. By

关键词： Riemann Conjecture geometric analysis Symmetry Alternative Oscillation Single Peak Peak-Valley Structure