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curvature-controlled band alignment transition in 1D van der Waals heterostructures

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npj Computational Materials 2023年第1期9卷 1411-1419页

作者： Shu Zhao Chunxia Yang Ziye Zhu Xiaoping Yao Wenbin Li School of Materials Science and Engineering Zhejiang University310027 HangzhouChina Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake University310030 HangzhouChina Institute of Advanced Technology Westlake Institute for Advanced Study310024 HangzhouChina

The effect of curvature on the band alignment of one-dimensional (1D) van der Waals (vdW) transition metal dichalcogenide(TMDC) heterostructures is studied by comprehensive first-principles calculations. We find that, as the diameter of a TMDCnanotube decreases, the combined effect of curvature-induced flexoelectricity and circumferential tensile strain causes a rapidlowering of the conduction band minimum, whereas the valence band maximum exhibits an initial lowering before rising. Asindividual TMDC nanotubes form coaxial heterostructures, the concerted effect of diameter-dependent band-edge levels andintertube coupling via flexovoltage can result in a transition of intertube band alignment from Type II to Type I in multipleheterostructural systems, including large-diameter MoSe_(2)@WS_(2), MoTe_(2)@MoSe_(2), and MoTe_(2)@WS_(2) heterostructures. These results laydown a foundation for the rational design of 1D vdW heterostructures.

关键词： alignment curvature band

curvature-induced lipid segregation

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Chinese Physics B 2015年第6期24卷 95-99页

作者：郑斌孟庆田 Robin L.B.Selinger Jonathan V.Selinger 叶方富 College of Physics and Electronics Shandong Normal University Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics of Chinese Academy of Sciences Institute of PhysicsChinese Academy of Sciences Liquid Crystal Institute Kent State University

We investigate how an externally imposed curvature influences lipid segregation on two-phase-coexistent membranes. We show that the bending-modulus contrast of the two phases and the curvature act together to yield a reduced effective line tension. On largely curved membranes, a state of multiple domains （or rafts） forms due to a mechanism analogous to that causing magnetic-vortex formation in type-II superconductors. We determine the criterion for such a multi-domain state to occur; we then calculate respectively the size of the domains formed on cylindrically and spherically curved membranes.

关键词： curvature phase separation lipid membrane rafts

curvature Dependence of Interfacial Properties for Associating Lennard-Jones Fluids:A Density Functional Study

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Chinese Physics Letters 2011年第2期28卷 168-171页

作者： SUN Zong-Li KANG Yan-Shuang Science and Technology College North China Electric Power UniversityBaoding 071051 College of Science Agriculture University of HebeiBaoding 071001

Classical density functional theory is used to study the associating Lennard Jones fluids in contact with spherical hard wall of different curvature *** interfacial properties including contact density and fluid-solid intcrfacial tension are *** influences of associating energy,curvature of hard wall and the hulk density of fluids on these properties are analyzed in *** results may provide helpful clues to understand the interfacial properties of other complex fluids.

关键词： curvature interfacial spherical

curvature and Hybridization Effects on the Persistent Current of a Carbon Nanotorus

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Chinese Physics Letters 2009年第7期26卷 218-221页

作者：徐宁丁建文陈宏波马明明 Department of Physics and Institute for Nanophysics and Rare-earth Luminescence Xiangtan University Xiangtan 411105

To accurately describe the persistent current for various toroidad carbon nanotubes （TCNs）, a semiempirical sp3 tight-binding model is presented, in which the intrinsic curvature and hybridization have been fully taken into account. The calculations show that the curvature and hybridization can induce dramatic changes in the energy spectra of TCNs such as the Fermi energy EF shifting up, an energy gap opening at IF, F, and the energy spectrum symmetry about EF destroyed, which leads to a decrease of persistent current and changes in the shape Of the flux-dependent current. In the presence of curvature and hybridization, the persistent current in non-armchair TCNs is nearly an order of magnitude lower than that obtained by using the Brillouin-zone folding approach, while it is of the same order of magnitude in armchair TCNs.

关键词： CARBON nanotubes curvature HYBRIDIZATION EMPIRICAL research SPECTRUM analysis ENERGY gaps (Physics) SYMMETRY (Physics) BRILLOUIN zones

curvature derived from LiDAR digital elevation models as simple indicators of debris-flow susceptibility

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Journal of Mountain Science 2019年第1期16卷 95-107页

作者： Atsuko NONOMURA Shuichi HASEGAWA Hideo MATSUMOTO Mari TAKAHASHI Mina MASUMOTO Kazuhito FUJISAWA Faculty of Engineering and design Kagawa University Institute of Education Research and Regional Cooperation for Crisis Management Shikoku Kagawa University Faculty of Engineering Graduate school of Engineering Kagawa University

To mitigate the damage caused by debris flows resulting from heavy precipitation and to aid in evacuation plan preparation, areas at risk should be mapped on a scale appropriate for affected individuals and communities. We tested the effectiveness of simply identifying debris-flow hazards through automated derivation of surface curvatures using LiDAR digital elevation models. We achieved useful correspondence between plan curvatures and areas of existing debris-flow damage in two localities in Japan using the analysis of digital elevation models(DEMs). We found that plan curvatures derived from 10 m DEMs may be useful to indicate areas that are susceptible to debris flow in mountainous areas. In residential areas located on gentle sloping debris flow fans, the greatest damage to houses was found to be located in the elongated depressions that are connected to mountain stream valleys. Plan curvaturederived from 5 m DEM was the most sensitive indicators for susceptibility to debris flows.

关键词： Digital elevation model LiDAR Gridspacing Debris flow Geological hazard curvature

curvature detail representation of triangular surfaces

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第7期7卷 1210-1214页

作者： WU Jin-zhong LIU Xue-hui WU En-hua State Key Lab of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100080 China Department of Computer and Information Science University of Macao Macao China Graduate University of Chinese Academy of Sciences Beijing 100039 China

curvature tells much about details of surfaces and is studied widely by researchers in the computer graphics com- munity. In this paper, we first explain the mean-curvature view of Dirichlet energy of triangular surfaces and introduce a curvature representation of details, and then present surfaces editing applications based on their curvature representation. We apply our method to surfaces with complex boundaries and rich details. Results show the validity and robustness of our method and dem- onstrate curvature map can be a helpful surfaces detail representation.

关键词： curvature Detail representation Mesh editing Shape editing Dirichlet energy

Designing planar cubic B-spline curves with monotonic curvature for curve interpolation

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Computational Visual Media 2020年第3期6卷 349-354页

作者： Aizeng Wang Chuan He Fei Hou Zhanchuan Cai Gang Zhao School of Mechanical Engineering&Automation Beihang UniversityBeijing 100191China State Key Laboratory of Virtual Reality Technology&Systems Beihang UniversityBeijing 100191China State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Faculty of Information Technology Macao University of Science and TechnologyMacao 999078China

Monotonic curvature plays an important role in industrial design and styling of curves with aesthetic shapes,e.g.,in automobile and aircraft design[1].Used in conventional parametric CAD/CAM systems,general B-splines are not adequate for aesthetic *** for the straight line and circle,monotonic curvature distribution,associated with pleasing shape,is very difficult to achieve.

关键词： curvature monotonic curves

Damage detection of a thin plate using modal curvature via macrostrain measurement

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 409-424页

作者： Ting Yu Hsu Yi Cheng Shih Quang-Vinh Pham Department of Civil and Construction Engineering Taiwan University of Science and Technology Chung-Shan Institute of Science and Technology

Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural health. Modal curvature-based damage detection techniques have recently garnered considerable attention from the research community, and have become a promising vibration-based structural health monitoring solution. However, computing errors arise when calculating modal curvatures from lateral mode shapes, which result from unavoidable measurement errors in the mode shapes as identified from lateral vibration signals; this makes curvature-based algorithms that use a lateral measurement only theoretically feasible, but practically infeasible. Therefore, in this study, long-gauge fiber Bragg grating strain sensors are employed to obtain a modal curvature without a numerical differentiation procedure in order to circumvent the computing errors. Several damage indices based on modal curvatures that were developed to locate beam damage are employed. Both numerical and experimental studies are performed to validate the proposed approach. However, although previous studies have reported relative success with the application of these damage indices on a simple beam, only one damage index demonstrated the capability to locate damage when the stiffness of the local region changed near the sensor.

关键词： macro strain long gauge modal curvature plate damage detection

Five-axis flank milling tool path generation with curvature continuity and smooth cutting force for pockets

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Chinese Journal of Aeronautics 2020年第2期33卷 730-739页

作者： Changqing LIU Yingguang LI Xin JIANG Wenyao SHAO College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In order to ensure machining stability,curvature continuity and smooth cutting force are very important so as to meet the constraints of both cutting force and kinematics of machine *** five-axis flank milling,it is difficult to meet both of the constraints because tool path points and tool axis vectors interact with each *** this paper,multiple relationships between tool path points and tool axis vectors with cutting force and kinematics of machine tools are established,and the strategies of corner-looping milling and clothoidal spirals are combined so as to find feasible solutions under both of the *** path parameters are iterated by considering the maximum cutting force and the feasible range of the tool axis vector,and eventually a curvature continuity five-axis flank milling tool path with smooth cutting force is *** experimental results show that the conditions of cutting force are satisfied,vibration during the process of machining is reduced,and the machining quality of the surface is improved.

关键词： curvature continuity Cutting force Five-axis flank milling Machining Tool path generation