检索结果-南通市图书馆

Tensor products of coherent configurations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2022年第5期17卷 829-852页

作者： Gang Chen Ilia PONOMARENKO School of Mathematics and Statistics Central China Normal UniversityWuhan 430079China Steklov Institute of Mathematics at St.Petersburg Russia Sobolev Institute of Mathematics NovosibirskRussia

A Cartesian decomposition of a coherent configuration✗is defined as a special set of its parabolics that form a Cartesian decomposition of the underlying set.It turns out that every tensor decomposition of✗comes from a certain Cartesian decomposition.It is proved that if the coherent configuration✗is thick,then there is a unique maximal Cartesian decomposition of✗;i.e.,there is exactly one internal tensor decomposition of✗into indecomposable components.In particular,this implies an analog of the Krull–Schmidt theorem for the thick coherent configurations.A polynomial-time algorithm for finding the maximal Cartesian decomposition of a thick coherent configuration is constructed.

关键词： Coherent configuration Cartesian decomposition Krull-Schmidt theorem

Analysis of a class of globally divergence-free HDG methods for stationary Navier-Stokes equations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第5期67卷 1133-1158页

作者： Gang Chen Xiaoping Xie School of Mathematics Sichuan University Chengdu 610064China

In this paper,we analyze a class of globally divergence-free(and therefore pressure-robust)hybridizable discontinuous Galerkin(HDG)finite element methods for stationary Navier-Stokes equations.The methods use the P_(k)/P_(k-1)(k≥1)discontinuous finite element combination for the velocity and pressure approximations in the interior of elements,piecewise Pm(m=k,k-1)for the velocity gradient approximation in the interior of elements,and piecewise P_(k)/P_(k) for the trace approximations of the velocity and pressure on the inter-element boundaries.We show that the uniqueness condition for the discrete solution is guaranteed by that for the continuous solution together with a sufficiently small mesh size.Based on the derived discrete HDG Sobolev embedding properties,optimal error estimates are obtained.Numerical experiments are performed to verify the theoretical analysis.

关键词： Navier-Stokes equations HDG methods divergence-free uniqueness condition error estimates

On the Kernel of Restriction of Characters

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2022年第1期43卷 59-62页

作者： Gang Chen Jiawei HE School of Mathematics and Statistics Central China Normal UniversityWuhan 430079China

Let G be a finite group, H be a proper subgroup of G, and S be a unitary subring of C. The kernel of the restriction map S[Irr(G)] → S[Irr(H)] as a ring homomorphism is studied. As a corollary, the main result in [Is... 详细信息

关键词： Characters Character ring Character restriction

Stability Analysis of Systems With Time-varying Delay via a Novel Lyapunov Functional

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2019年第4期6卷 1068-1073页

作者： Yun chen Gang Chen the School of Electrical and Information Engineering Hunan University of TechnologyZhuzhou 412007 the Key Laboratory for Electric Drive Control and Intelligent Equipment of Hunan Province Zhuzhou 412007China

This paper investigates the stability problem for time-varying delay systems.To obtain a larger delay bound,this paper uses the second-order canonical Bessel-Legendre(BL)inequality.Secondly,using four couples of integral terms in the augmented Lyapunov-Krasovskii function(LKF)to enhance the relationship between integral functionals and other vectors.Furthermore,unlike the construction of the traditional LKF,a novel augmented LKF is constructed with two new delayproduct-type terms,which adds more state information and leads to less conservative results.Finally,two numerical examples are provided to demonstrate the effectiveness and the significant improvement of the proposed stability criteria.

关键词： Integral inequality Lyapunov theorem stability time-delay systems

Antiviral activity of mangiferin from the rhizome of Anemarrhena asphodeloides against herpes simplex virus type 1

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2023年第3期13卷 112-120页

作者： Wen-Da Wang Gang Chen Huzhou Hospital of Traditional Chinese Medicine Affiliated to Zhejiang University of Traditional Chinese Medicine Huzhou 313001China

Objective:To evaluate the antiviral activity of pure compounds against herpes simplex virus type 1(HSV-1)from the rhizome of Anemarrhena asphodeloides.Methods:Bioassay-guided isolation was conducted to separate the active compound and its chemical structure was elucidated by spectral analysis.In vitro antiviral efficacy of active compound was detected by Cell Counting Kit-8 assay,plaque reduction assay,and fluorescence observation.RT-PCR was used to determine the viral load and the cytokine-related gene expression after HSV-1 infection.In vivo study was also conducted to further determine antiviral efficacy of an active compound against HSV-1.Results:An active compound was isolated and elucidated as mangiferin.Mangiferin significantly inhibited the replication of HSV-1 in Vero cells with a half maximal inhibitory concentration(IC_(50))of 64.0 mg/L.Time-of-addition and time-of-removal assays demonstrated that mangiferin could effectively inhibit the replication of HSV-1 in the early stage(8 h).UL12,UL42,and UL54 gene expression levels of HSV-1 in the 64 mg/L mangiferin-treated group were markedly reduced as compared with the HSV-1 group(P<0.01).Fluorescence observation showed that mangiferin attenuated the mitochondrial damage maintainingΔΨm induced by HSV-1 in Vero cells.The expression of inflammatory factors TNF-α,IL-1β,and IL-6 was remarkably increased in the virus-infected group as compared with that in the normal group(P<0.05),the levels of these inflammatory factors dropped after treatment with mangiferin.Mangiferin significantly decreased the viral load and attenuated the HSV-1-induced up-regulation of TNF-α,IL-1β,and IL-6.The relative protection rate of HSV-1-infected mice could reach up to55.5%when the concentration of mangiferin was 4 g/kg.Conclusions:Mangiferin exhibits promising antiviral activity against HSV-1 in vitro and in vivo and could be a potential antiviral agent for HSV-1.

关键词： Anemarrhena asphodeloides Herpes simplex virus Antiviral activity Mangiferin

Dental stem cell-derived extracellular vesicles as promising therapeutic agents in the treatment of diseases

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Oral Science 2022年第1期14卷 31-39页

作者： Ye Li Xu Duan Yinxue chen Bingyun Liu Gang Chen The State Key Laboratory Breeding Base of Basic Science of Stomatology(Hubei-MOST)&Key Laboratory of Oral Biomedicine Ministry of Education School and Hospital of StomatologyWuhan UniversityWuhanChina Department of Oral and Maxillofacial Surgery School and Hospital of StomatologyWuhan UniversityWuhanChina Frontier Science Center for Immunology and Metabolism Wuhan UniversityWuhanChina

Dental stem cells(DSCs), an important source of mesenchymal stem cells(MSCs), can be easily obtained by minimally invasive procedures and have been used for the treatment of various diseases. Classic paradigm attributed the mechanism of their therapeutic action to direct cell differentiation after targeted migration, while contemporary insights into indirect paracrine effect opened new avenues for the mystery of their actual low engraftment and differentiation ability in vivo. As critical paracrine effectors, DSC-derived extracellular vesicles(DSC-EVs) are being increasingly linked to the positive effects of DSCs by an evolving body of in vivo studies. Carrying bioactive contents and presenting therapeutic potential in certain diseases, DSC-EVs have been introduced as promising treatments. Here, we systematically review the latest in vivo evidence that supports the therapeutic effects of DSC-EVs with mechanistic studies. In addition, current challenges and future directions for the clinical translation of DSC-EVs are also highlighted to call for more attentions to the(Ⅰ) distinguishing features of DSC-EVs compared with other types of MSC-EVs,(Ⅱ)heterogeneity among different subtypes of DSC-derived EVs,(Ⅲ) action modes of DSC-EVs,(Ⅳ) standardization for eligible DSC-EVs and(Ⅴ) safety guarantee for the clinical application of DSC-EVs. The present review would provide valuable insights into the emerging opportunities of DSC-EVs in future clinical applications.

关键词： therapeutic treatment insight

Comparative Study on the Physical Properties of Edgeworthia and Wikstroemia Handmade Paper

在线全文

学校读者我要写书评

暂无评论

Paper And Biomaterials 2023年第3期8卷 11-20页

作者： Ruxuan Zhao Gang Chen Department of Cultural Heritage and Museology Fudan UniversityShanghai200433China

Both Edgeworthia and Wikstroemia have been used traditionally in hand papermaking in China.As plants from the Thymelaeaceae family,these species have been mentioned periodically and have been mixed or substituted with each other.This study reviewed their papermaking background and status,and selected one of the Edgeworthia and three of the Wikstroemia raw materials that are still in use.Pulp was cooked under the same conditions in the laboratory,and handsheets of pure and mixed materials were obtained using a Rapid-Köthen sheet former.A series of physical properties,such as color,structure,and mechanical properties were tested,followed by a comparison and discussion of the raw material properties.The results show that Wikstroemia fibers are generally thinner and shorter,but there are variations between the different genera of raw materials.Thus,compared with Edgeworthia,Wikstroemia has some advantages in tensile strength,although it shows some disadvantages when it comes to tearing strength.The performance of a mixed-ingredient paper sheet falls between the performance of two pure-component papers.For cost and performance reasons,adding a small amount of Wikstroemia(e.g.,<20%)to Edgeworthia is preferable.

关键词： handmade paper paper properties Edgeworthia Wikstroemia mixed-ingredient paper

Robust mismatched filtering algorithm for passive bistatic radar using worst-case performance optimization

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2020年第7期21卷 1074-1084页

作者： Gang Chen Jun WANG National Laboratory of Radar Signal Processing Xidian UniversityXi'an 710071China

Passive bistatic radar detects targets by exploiting available local broadcasters and communication transmissions as illuminators, which are not designed for radar. The signal usually contains a time-varying structure, which may result in high-level range ambiguity sidelobes. Because the mismatched filter is effective in suppressing sidelobes, it can be used in a passive bistatic radar. However, due to the low signal-to-noise ratio in the reference signal, the sidelobe suppression performance seriously degrades in a passive bistatic radar system. To solve this problem, a novel mismatched filtering algorithm is developed using worst-case performance optimization. In this algorithm, the influence of the low energy level in the reference signal is taken into consideration, and a new cost function is built based on worst-case performance optimization. With this optimization, the mismatched filter weights can be obtained by minimizing the total energy of the ambiguity range sidelobes. Quantitative evaluations and simulation results demonstrate that the proposed algorithm can realize sidelobe suppression when there is a low-energy reference signal. Its effectiveness is proved using real data.

关键词： Passive bistatic radar Range sidelobes Low signal-to-noise ratio Mismatched filtering Worst-case performance optimization

Fluid-structure interaction simulation for multi-body flexible morphing structures

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 137-147页

作者： Wenzhi GUO Yongtao SHUI Lu NIE Gang Chen State Key Laboratory of Strength and Vibration for Mechanic Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China China Academy of Launch Vehicle Technology Beijing 100076China China Academy of Aerospace Science and Innovation Beijing 100086China Shannxi Key Laboratory of Service Environment and Control for Flight Vehicles Xi’an Jiaotong UniversityXi’an 710049China

The multi-body flexible morphing airfoil can improve the aerodynamic characteristics based on different flight missions continuously.Recently researches have focused on the unsteady aerodynamic characteristics of flexible wings under passive actuation.However,the unsteady aerodynamic characteristics with the fluid-structure interaction effects in the multi-body active actuation process of morphing airfoil deserve further investigation.In this paper,a fluid-structure coupled simulation method for multi-body flexible morphing airfoil with active actuation subsystem was investigated,and the aerodynamic characteristics during deformation were compared with different skin flexibility,flow field environment,actuation mode and actuation time.The numerical results show that for the steady aerodynamic,the skin flexibility can improve the stability efficiency.In the unsteady process,the change trend of the transient lift coefficient and pitching moment are consistent with those of the active drive characteristics,while the instantaneous lift-drag ratio coefficient is greatly affected by the driving mode and can be improved by increasing the driving duration.

关键词： Fluid-structure interaction Multi-body dynamics modeling Flexible structures Aerodynamics Morphing wings