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Chinese Journal of Chemical Physics 2016年第6期29卷 650-656,I0001页

作者： Li-bo Zhang Hui Fang Shun-li Chen Xue-feng Zhu Wei Gan LaboratoryofEnvironmentalScienceandTechnology TheXinjiangTechnicalInstituteofPhysicsChemistryKeyLaboratoryofFunctionalMaterialsandDevicesforSpecialEnvironmentsChineseAcademyofSciencesUrumqi830011China UniversityofChineseAcademyofSciences Beijing100049China

The orientation angle is an important parameter that reflects the structure of molecules at interfaces. In order to obtain this parameter, second order nonlinear spectroscopic techniques including second harmonic generation （SHG） and sum frequency generation-vibrational spec- troscopy （SFG-VS） have been successfully applied through analysis of the nonlinear signal from various polarizations. In some SHG and SFG-VS experiments, total internal reflection （TIR） configuration has been adopted to get enhanced signals. However, the reports on the detailed procedure of the polarization analysis and the calculation of the orientation angle of interracial molecules under TIR configuration are still very few. In this paper, we mea- sured the orientation angles of two molecules at the hexadecane-water interface under TIR and Non-TIR experimental configurations. The results measured from polarization analysis in TIR configuration consist with those obtained from Non-TIR configuration. This work demonstrates the feasibility and accuracy of polarization analysis in the determination of the orientation angle of molecules at the interfaces under TIR-SHG configuration.

关键词： Second harmonic generation Total internal reflection Hyperpolarizability Polarization orientation angle

Phase-field-crystal simulation of nano-single crystal microcrack propagation under different orientation angles

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Chinese Physics B 2023年第4期32卷 443-451页

作者：彭敦维张云鹏田晓林侯华赵宇宏 School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048China School of Materials Science and Engineering North University of ChinaTaiyuan 030051China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China

The propagation mechanism of microcracks in nanocrystalline single crystal systems under uniaxial dynamic and static tension is investigated using the phase-field-crystal *** dynamic and static stretching results show that different orientation angles can induce the crack propagation mode,microscopic morphology,the free energy,crack area change,and causing fracture *** propagation mode depends on the dislocation activity near the crack *** propagation of the crack occurs due to dislocation always at crack *** is emitted at the front end of the crack tip and plastic deformation occurs,which belongs to ductile *** orientation angles of 9°and 14°are brittleductile mixed propagation,while the orientation angles of 19°and 30°are brittle propagation and no dislocation is formed under dynamic *** vacancy and vacancy connectivity phenomenon would appear when the orientation angle is14°under static tension,and the crack would be ductile *** the orientation angle is 19°and 30°,the crack propagates in a certain direction,which is a kind of brittle *** work has some practical significance in preventing material fracture failure and improving material performance.

关键词： phase-field-crystal microcrack orientation angle crack propagation

Reclined trend of alkyl chain of sodium dodecylbenzenesulfonate molecules induced by friction

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Friction 2022年第9期10卷 1353-1364页

作者： Xianzhang WANG Yuan LIU Liran MA Xuefeng XU Yu TIAN State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Technology Beijing Forestry UniversityBeijing 100083China

Surfactants tend to adsorb on the surface/interface mostly in a directional *** alkyl chain orientation and conformation order for molecular monolayers of sodium dodecylbenzenesulfonate(SDBS)at low concentrations are studied by using the sum frequency generation vibrational spectroscopy(SFG-VS).The molecular arrangement of the surfactants adsorbed at the solid/liquid interface is further *** is found that the arrangement of the SDBS at the interface becomes relatively ordered with increasing bulk ***,the orientation angle reduces gradually,and the molecules tend to be upright *** addition,the effect of friction on the conformation order and orientation angle are also *** intensity of the SDBS vibrational contraction peak becomes lower after friction,which indicates that the anion has a reorientation process at the *** arrangement of molecules becomes more disordered due to *** orientation angle increases slightly,which indicates the monolayer has an inclined trend relative to the lateral direction on the interface.A modified adsorption model considering friction effect is *** work may provide a reference for the further study of adsorption mechanism and application of surfactants.

关键词： friction lubricating film sum frequency generation(SFG) orientation angle conformation order

DOA and Subarray-Interval Estimation for Arbitrarily Distributed UAV Swarm System

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China Communications 2023年第4期20卷 102-117页

作者： Dian Fan Yue Zhu Jia You Zhe Wang Nan Zhong The China Academy of Information and Communications Technology Beijing 100191China The China Academy of Railway Sciences Corporation Limited Beijing 100081China

In this paper,DOA and subarray-interval estimation are considered and applied to arbitrarily distributed unmanned aerial vehicle(UAV)swarm system,in which multiple small UAVs containing uniform linear array(ULA)are divided by unknown intervals because of dynamic *** parameters are taken to indicate the steering vector,namely,the direction of arrivals(DOAs)of target users,the intervals of UAVs,and the orientation angles of *** orientation angles are first estimated with an auxiliary user and the DOAs are obtained through a search free rooting method,despite the intervals among the ***,the intervals among UAVs can also be calculated via exhaustive when the number of target users are no less than *** further develop a low-complex method to reduce the computational complexity during subarray-interval *** deterministic Cramér-Rao bound(CRB)of the DOA,orientation angle and subarray-interval can be inferred in a closed ***,numerical instances are cited to verify the research results.

关键词： distributed subarray DOA orientation angle subarray-interval CRB

Analysis of Localization of Mohr-Coulomb Strength Law with Damage Effect

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Journal of Shanghai Jiaotong university(Science) 2012年第5期17卷 619-628页

作者：王忠昶王海涛杨庆 School of Civil and Safety Engineering Dalian Jiaotong University School of Civil Engineering Dalian University of Technology

The damage critical curved surface is derived by considering the related effect of isotropic damage and degradation of cohesion and internal friction angle of Mohr-Coulomb strength *** characteristics of stress-displacement curve and networks of shear bands with the change of degree of damage,confining pressure and Poisson's ratio are investigated numerically by monitoring the stress-displacement values in the process of deformation of samples under plane strain and different initial *** dependence of elastic-plastic response of localization is *** non-uniqueness of the solution of equation is *** orientation angle of shear band is derived by considering the related effect of isotropic damage and degradation of cohesion and internal friction *** orientation angle of shear band obtained by numerical simulation is contrasted to the orientation angle by measuring Mohr *** is shown that peak strength and residual strength depend on confining *** networks of shear bands begin to appear in phaseⅡof elasticity and develop in soften phase,and the shear band is formed in the phase of residual *** the degree of damage increases,axial displacement at the points of bifurcation and shear band *** orientation angle of shear band increases with the increase of the damage *** orientation angle of shear band obtained by numerical simulation and measuring Mohr circle is not much difference when the damage degree is *** Mohr-Coulomb theory may predict the localized instability of sample by considering the degradation of cohesion and internal friction angle.

关键词： bifurcation shear band damage orientation angle Mohr-Coulomb strength law

Determination of Anisotropic Factors of Pyrolytic Carbon by Electron Diffraction

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Chinese Journal of Biomedical Engineering(English Edition) 2021年第3期30卷 105-110页

作者： ZHANG Jian-hui ZHA Xiao SUN Hai-bo School of Mechanical Engineering Hangzhou Dianzi UniversityHangzhou 310018China

The preferred orientation of pyrolytic carbon coating is an important performance parameter for the safe use of artificial mechanical heart *** this paper,the selected area electron diffraction(SAED)analysis of pyrolytic carbon coating samples of artificial heart valve was carried out by transmission electron microscopy(TEM),and the experimental method of characterizing the preferred orientation of pyrolytic carbon by electron diffraction spectrum,namely bacon anisotropy factor(BAF),was described,and the orientation angle and BAF corresponding to the electron diffraction spectrum were *** results show that the BAF value can directly reflect the anisotropy of pyrolytic carbon in the selected *** BAF value range is from 1 to infinity,and the higher the preferred orientation is,the greater the value *** BAF value decreases exponentially with the increase of orientation *** the pyrolytic carbon tends to be isotropic,the orientation angle tends to 180 and the BAF value tends to 1.

关键词： artificial heart valve pyrolytic carbon coating preferred orientation orientation angle bacon anisotropy factor

A Novel Line Segments Extraction Algorithm Based on DBSCAN Method

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A Novel Line Segments Extraction Algorithm Based on DBSCAN M...