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Adaptive triangular mesh coarsening with centroidal Voronoi tessellations

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 535-545页

作者： zhen-yu SHU guo-zhao WANG Chen-shi DONG Institute of Computer Graphics and lmage Processing Department of Mathematics Zhejiang University Hangzhou 310027 China Laboratory of Information and Optimization Technologies Ningbo Institute of Technology Zhejiang University Ningbo 315100 China

We present a novel algorithm for adaptive triangular mesh coarsening. The algorithm has two stages. First, the input triangular mesh is refined by iteratively applying the adaptive subdivision operator that performs a so-called red-green split. Second, the refined mesh is simplified by a clustering algorithm based on centroidal Voronoi tessellations (CVTs). The accuracy and good quality of the output triangular mesh are achieved by combining adaptive subdivision and the CVTs technique. Test results showed the mesh coarsening scheme to be robust and effective. Examples are shown that validate the method.

关键词： Triangular mesh Mesh coarsening Surface subdivision Centroidal Voronoi tessellations (CVTs)

Review:Research progress on Fabry-Perot resonator antenna

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 583-588页

作者： zhen-guo LIU Zhi-chen GE Xi-yuan CHEN State Key Lab of Millimeter Waves Southeast University Nanjing 210096 China zhenjiang Entry-Exit Inspection and Quarantine Bureau Zhenjiang 212003 China Department of lnstrument Science and Engineering Southeast University Nanjing 210096 China

The Fabry-Perot resonator (FPR) antenna has found wide applications in microwave and millimeter waves and recently attracted considerable interest. In this paper, a summary of planar and cylindrical structures, analytic models and research development is presented, and a comparison between these structures and analytic models is made, showing that such analytic models as the FP cavity mode, electromagnetic band gap (EBG) defect mode, transmission line mode, and leaky-wave mode are consistent when applied to analyze this type of resonator antenna. Some interesting topics under recent research, including dual or multi-band, improvement of gain bandwidth, low profile and beam control, are surveyed.

关键词： Fabry-Perot resonator (FPR) antenna Electromagnetic band gap (EBG) resonator antenna Leaky-wave antenna Defect mode Artificial magnetic conductor (AMC) Frequency selective surface (FSS)

Integrated Entry Guidance for Reusable Launch Vehicle

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Chinese Journal of Aeronautics 2007年第1期20卷 1-8页

作者： NING guo-dong ZHANG Shu-guang FANG zhen-ping School of Aeronautical Science and Technology Beijing University of Aeronautics and Astronautics Beijing 100083 China

A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertainties are presented to demonstrate the capacity and reliability of this method.

关键词： guidance trajectory generation entry onboard constraint robustness

The Mobility of Threadedα-Cyclodextrins in PR Copolymer and Its Influences on Mechanical Properties

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Chinese Journal of Polymer Science 2017年第6期35卷 752-763页

作者： Zhi Yan 叶霖 Ai-ying Zhang zeng-guo Feng School of Materials Science and Engineering Beijing Institute of Technology Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications

The methylated polyrotaxane （MePR） copolymer was prepared via the methylation of hydroxyl of threaded α-cyclodextrin （α-CDs） in polyrotaxane （PR） copolymer by CH3I/NaH. Its structure was characterized by GPC, IR and NMR. The WXRD and TGA measurements showed the destruction of channel-like crystalline structure in MePR copolymer. The sliding of threaded α-CDs along PEG axis in PR and MePR copolymers was demonstrated by their dielectric spectra that also evidenced the presence of rotating of threaded α-CDs around PEG axis in MePR eopolymer. The frequent and vigorous molecular mobility in MePR and PR copolymers was also verified by dynamic mechanical analysis （DMA） and rheological measurement, which was possibly assigned to the sliding and rotating of threaded α-CDs. DMA and rheological results showed that the mobility of α-CDs could simultaneously strengthen and toughen PR copolymer proved by stress-stain curves. In this paper, we report the CD mobility in PR and MePR copolymers. The macroscopic behaviors of PR copolymer, such as mechanical properties in solid state, were also found to be benefited from CD mobility.

关键词： PR copolymer Methylation CD mobility Dielectric measurement Mechanical property

Addition of the T5 exonuclease increases the prime editing efficiency in plants

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Journal of Genetics and Genomics 2023年第8期50卷 582-588页

作者： zhen Liang Yuqing Wu Yingjie guo Sha Wei School of Life Science Shanxi UniversityTaiyuanShanxi 030006China Research Institute of Big Data Science and Industry Shanxi UniversityTaiyuanShanxi 030006China

Prime editing(PE)is a versatile genome editing tool without the need for double-stranded DNA breaks or donor DNA templates,but is limited by low editing *** previously fused the M-MLV reverse transcriptase to the Cas9 nickase,generating the PE2(v1)system,but the editing efficiency of this system is still *** we develop different versions of PE2 by adding the 50-to-30 exonuclease at different positions of the nCas9-M-MLV RT fusion ***2(v2),in which the T5 exonuclease fused to the N-terminus of the nCas9-MMLV fusion protein enhances prime editing efficiency of base substitutions,deletions,and insertions at several genomic sites by 1.7-to 2.9-fold in plant cells compared to PE2(v1).The improved editing efficiency of PE2(v2)is further confirmed by generating increased heritable prime edits in stable transgenic plants compared to the previously established PE-P1,PE-P2,and PPE *** PE2(v2),we generate herbicide-resistant rice by simultaneously introducing mutations causing amino acid substitutions at two target *** PE efficiency is further improved by combining PE2(v2)and *** together,the increased genome editing efficiency of PE2(v2)developed in this study may enhance the applications of PE in plants.

关键词： Prime editing CRISPR T5 exonuclease Genome editing

M_(φ)-type Submodules over the Bidisk

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Acta Mathematica Sinica,English Series 2021年第5期37卷 805-824页

作者： guo zeng YANG Chang Hui WU Tao YU School of Mathematics and Statistics Zhengzhou Normal UniversityZhengzhou 450044P.R.China School of Mathematical Sciences Qufu Normal UniversityQufu 273165P.R.China School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China

Let H^(2)(D^(2))be the Hardy space over the bidisk D^(2),and let M_(φ)=[(z-φ(w))^(2)]be the submodule generated by(z-φ(w))^(2),whereφ(w)is a function in H∞(w).The related quotient module is denoted by N_(φ)=H^(2)(D^(2))ΘM_(φ).In the present paper,we study the Fredholmness of compression operators S_(z),S_(w) on N_(φ).Whenφ(w)is a nonconstant inner function,we prove that the Beurling type theorem holds for the fringe operator F_(w) on[(z-w)^(2)]Θz[(z-w)^(2)]and the Beurling type theorem holds for the fringe operator Fz on M_(φ)ΘwM_(φ)ifφ(0)=***,we study some properties of F_(w) on[(z-w^(2))^(2)]Θz[(z-w^(2))^(2)].

关键词： Submodules Beurling type theorem compression operators Fredholmness

Global Weak Solutions to a Fluid-particle System of an Incompressible Non-Newtonian Fluid and the Vlasov Equation

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Acta Mathematicae Applicatae Sinica 2024年第4期40卷 954-978页

作者： Pei-yu ZHANG Li FANG zhen-hua guo Department of Mathematics Northwest UniversityXi’an 710127China School of Mathematics and Information Science&Center for Applied Mathematics of Guangxi Guangxi UniversityNanning 530004China

The purpose of this work is to investigate the existence and uniqueness of weak solutions to the initial-boundary value problem for a coupled system of an incompressible non-Newtonian fluid and the Vlasov *** coupling arises from the acceleration in the Vlasov equation and the drag force in the incompressible viscous non-Newtonian fluid with the stress tensor of a power-law structure for p≥11/*** main idea of the existence analysis is to reformulate the coupled system by means of a so-called truncation *** advantage of the new formulation is to control the external force term G=-∫Rd(u-v)fdc(d=2,3).The global existence of weak solutions to the reformulated system is shown by using the Faedo-Galerkin method and weak compactness *** further prove the uniqueness of weak solutions to the considered system.

关键词： incompressible non-Newtonian fluid Vlasov equation global weak solutions

Stacking of Exfoliated Two-Dimensional Materials: A Review

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Chinese Journal of Chemistry 2020年第9期38卷 981-995页

作者： zhen Hu Zhi-Bo Liu Jian-guo Tian The Key Laboratory of Weak Light Nonlinear Photonics Ministry of EducotionTEDA Applied Physics Institute ond School of PhysicsNankai University Tianjin 300071China Renewable Energy Conversion and Storage Center Nankai UniversityTionjin 300384China

In recent years,two-dimensfonal(2D)atomic crystals represented by graphene have opened up new fields of 2D *** materials with atomic layer thickness are self-assembled into van der Waals heterostructures by weak van der Waals forces without considering lattice *** der Waals heterostructures can not only enhance the performance of its constituent materials but also show new ***-quality heterostructures require mechanically cleaved intrinsic 2D materials and flexible 2D material stacking ***,we summarize in detail the reliable exfoliation methods for large-area single-layer 2D materials and the dry and wet stacking techniques with high success *** twisted bilayer graphene is used as an example to briefly introduce the single-crystal tearing method,which is currently the most practical method for preparing isotropic twisted heterostructures with high-precision rotation *** hope to provide a valuable reference for researchers of 2D materials.

关键词： twisted preparing method

An assessment method of annual climatic status in China using extreme climate indices:2021 as an example

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Advances in Climate Change Research 2022年第6期13卷 868-874页

作者： zeng-Yuan guo Li-Juan CHEN Bing XIE Climate Studies Key Laboratory National Climate CenterChina Meteorological AdministrationBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China

A proper assessment of annual climatic status(ACS)is conducive to rationally formulating disaster prevention and mitigation *** former definition of ACS lacks either information on extreme climate or an intuitive grade feature service to the *** ACS defined in the National Standard of the People's Republic of China(GBACS)only considers the accumulated climate effects of each weighted 10-d temperature/precipitation anomaly in a *** global warming,the losses caused by extreme climate events often have a significant impact on the grades of ACS,but this impact cannot be reasonably reflected by *** study proposed the assessment of ACS using extreme climate indices(extreme climate-based ACS(ECACS))and compared it with *** results indicated that GBACS and ECACS can be used to evaluate the ACS from different *** ECACS is an important supplement to the GBACS,especially considering the years with frequently occurring extreme climate *** sum of GBACS and ECACS is a reasonable and comprehensive way to evaluate the *** empirical orthogonal function(EOF)analysis indicated a uniform mode(EOF1)and a dipole mode(EOF2)in GBACS and ECACS in *** interannual variation characteristics of ECACS in northern and southern China(EOF2 pattern)are consistent with real climate features,which is conducive to providing better and more detailed regional information in the ACS forecast *** results have essential instructive and application value for ACS assessment and government decision making.

关键词： Extreme climate indices Annual climatic status Temperature Precipitation