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Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 1-20页

作者： Jianlin yi zheng WU Rongyu XIA zheng LI State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China

Elastic wave absorption at subwavelength scale is of significance in many engineering ***-Hermitian metamaterials show the ability in high-efficiency wave ***,the single functionality of metamaterials is an important limitation on their practical applications for lack of tunability and ***,we propose a tunable and reconfigurable non-Hermitian piezoelectric metamaterial bar,in which piezoelectric bars connect with resonant circuits,to achieve asymmetric unidirectional perfect absorption(UPA)and symmetric bidirectional perfect absorption(PA)at low *** two functions can be arbitrarily switched by rearranging shunted *** on the reverberation-ray matrix(RRM)method,an approach is provided to achieve UPA by setting an exceptional point(EP)in the coupled resonant *** using the transfer matrix method(TMM)and the finite element method(FEM),it is observed that a non-Hermitian pseudo-band forms between two resonant bandgaps,and the EP appears at the bottom of the *** addition,the genetic algorithm is used to accurately and efficiently design the shunted circuits for desired low-frequency UPA and *** present work may provide new strategies for vibration suppression and guided waves manipulation in wide potential applications.

关键词： non-Hermitian metamaterial exceptional point(EP) unidirectional perfect absorption(UPA) piezoelectric metamaterial reverberation-ray matrix(RRM)method genetic algorithm

The diversity and evolution of retroviruses:Perspectives from viral“fossils”

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Virologica Sinica 2022年第1期37卷 11-18页

作者： Jialu zheng Yutong Wei guan-Zhu Han Jiangsu Key Laboratory for Microbes and Functional Genomics College of Life SciencesNanjing Normal UniversityNanjing210023China

Retroviruses exclusively infect vertebrates,causing a variety of *** replication of retroviruses requires reverse transcription and integration into host *** infecting germline cells,retroviruses become inherited vertically,forming endogenous retroviruses(ERVs).ERVs document past viral infections,providing molecular fossils for studying the evolutionary history of *** this review,we summarize the recent advances in understanding the diversity and evolution of retroviruses from the perspectives of viral fossils,and discuss the effects of ERVs on the evolution of host biology.

关键词： Retroviruses Endogenous retroviruses(ERVs) Origin and evolution Diversity

Heteroscedasticity check in nonlinear semiparametric models based on nonparametric variance function

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Applied Mathematics(A Journal of Chinese Universities) 2008年第4期23卷 401-409页

作者： QU Xiao-yi LIN Jin-guan Dept. of Math. Southeast Univ. Nanjing 210096 China

The assumption of homoscedasticity has received much attention in classical analysis of regression. Heteroscedasticity tests have been well studied in parametric and nonparametric regressions. The aim of this paper is to present a test of heteroscedasticity for nonlinear semiparametric regression models with nonparametric variance function. The validity of the proposed test is illustrated by two simulated examples and a real data example.

关键词： heteroscedasticity check nonlinear semiparametric regression model asymptotic normality nonparametric variance function

Boundary Points,Minimal L^(2)Integrals and Concavity PropertyⅢ—Linearity on Riemann Surfaces and Fibrations over Open Riemann Surfaces

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2091-2152页

作者： Qi An guan Zhi Tong MI zheng YUAN School of Mathematical Sciences Peking UniversityBeijing 100871P.R.China School of Mathematics and Statistics Beijing Jiaotong UniversityBeijing 100044P.R.China Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190P.R.China

In this article,we consider a modified version of minimal L^(2) integrals on sublevel sets of plurisubharmonic functions related to modules at boundary points,and obtain a concavity property of the modified *** applications,we give characterizations for the concavity degenerating to linearity on open Riemann surfaces and on fibrations over open Riemann surfaces.

关键词： Minimal L^(2)integrals plurisubharmonic functions boundary points weakly pseudoconvex Kähler manifold

Influence of Liquid Isoprene Rubber on Strain Softening of Carbon Black Filled Isoprene Rubber Nanocomposites

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Chinese Journal of Polymer Science 2021年第7期39卷 887-895页

作者： Feng-yi Hou yi-Hu Song Qiang zheng MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

The reinforcement of rubbers by nanoparticles is always accompanied with enhanced dissipation of mechanical energy upon large *** for solving the contradiction between improving reinforcement and reducing energy dissipation for rubber nanocomposites have not been well *** carbon black(CB)filled isoprene rubber(IR)/liquid isoprene rubber(LR)blend nanocomposites with similar crosslink density(ve)are prepared and influence of LR on the strain softening behaviors including Payne effect under large amplitude shear deformation and Mullins effect under cyclic uniaxial deformation is *** introduction of LR could improve the frequency sensitivity of loss modulus and reduce critical strain amplitude for Payne effect and loss modulus at the low ***,tuning ve and LR content allows reducing mechanical hysteresis in Mullins effect without significant impact on the mechanical *** investigation is illuminating for manufacturing nanocomposite vulcanizates with balanced mechanical hysteresis and reinforcement effect.

关键词： Rubber nanocomposites Stress softening Mechanical hysteresis Liquid rubber

The Logarithmic Sobolev Inequality for a Submanifold in Manifolds with Nonnegative Sectional Curvature

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 487-496页

作者： Chengyang yi Yu zheng School of Mathematical Sciences East China Normal UniversityShanghai 200241China

The authors prove a sharp logarithmic Sobolev inequality which holds for compact submanifolds without boundary in Riemannian manifolds with nonnegative sectional curvature of arbitrary dimension and *** the Michael-Simon Sobolev inequality,this inequality includes a term involving the mean *** extends a recent result of Brendle with Euclidean setting.

关键词： Logarithmic Sobolev inequality Nonnegative sectional curvature Submanifold

Mining and Harvesting High Quality Topical Resources from the Web

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Chinese Journal of Electronics 2016年第1期25卷 48-57页

作者： ZHAO Wei guan Ziyu CAO zhengwen LIU zheng National Laboratory of Radar Signal Processing Xidian University College of Information and Technology Northwest University of China

Focused crawlers aim to effectively prioritize uncrawled URLs to harvest relevant pages while avoiding irrelevant ones. In practice, harvesting high quality topical Web resources is more important due to the explosion of Web information. Our study shows that the popular focused crawling strategy cannot achieve this *** this paper we develop a new focused crawler, namely On-line topical quality estimation(OTQE), which intelligently evaluates the topical quality of uncrawled pages by the observed link and content evidences and prioritize their URLs accordingly. The new crawler is scalable and requires fewer additional resources to do link-based analysis. The experimental results on crawling 3.6 million Web pages demonstrate the advantages of our proposed method over traditional focused crawlers.

关键词： Focused crawling Topical crawlers Clas sification Open directory project

Promising inhibitors targeting Mpro:an ideal strategy for anti-SARS-CoV-2 drug discovery

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Signal Transduction and Targeted Therapy 2020年第1期5卷 1008-1009页

作者： yi Chen guan Wang Liang Ouyang State Key Laboratory of Biotherapy and Cancer Center&Department of Gastrointestinal Surgery West China Hospitaland Collaborative Innovation Center of BiotherapySichuan University610041 ChengduChina

Recently,Dai W et *** a study on Science,1 in which the two lead compounds 11a and 11b were designed and synthesized based on the features of a key enzyme Mpro of SARSCoV-2(Fig.1).In particular,compound 11a is a potential drug candidate for coronavirus disease 2019(COVID-19)with strong anti-SARS-CoV-2 infection activity,good pharmacokinetics characteristics,and low toxicity.

关键词： al drug infection

Effect of Aging Treatment on Precipitation Behavior and Mechanical Properties of a Novel Aluminum–Lithium Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 671-677页

作者： Hua-guan Li Juan Ling yi-Wei Xu Zhong-Gang Sun Hong-Bing Liu Xing-Wei zheng Jie Tao College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology Shanghai Aircraft Manufacturing Company Limited

In this work, the microstructure and precipitation phases were primarily characterized by transmission electron microscopy. The mechanical properties were evaluated by tensile and tear test. The results indicated that the samples aged at 145 ℃ for 45 h or 155 ℃ for 30 h possessed a preferable combination of strength and plasticity, owing to the precipitation of well-dispersed T1 （A12CuLi） phases （diameter 〈 150 nm）. However, aging at more than 165 ℃ caused an obvious size growth of T1 plates, leading to the quick reduction in plasticity and toughness. Furthermore, the high Cu/Li ratio resulted in distinct precipitation features, including a shorter incubation time of T1 phase and the aggravated precipitate-free zones.

关键词： Aluminum-lithium alloy Aging treatment Fracture toughness Microstructure

Decline in semen concentration of healthy Chinese adults： evidence from 9357 participants from 2010 to 2015

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Asian Journal of Andrology 2018年第4期20卷 379-384页

作者： Hong-Fang Yuan Huang-Fang Shangguan yi zheng Tian-Qing Meng Cheng-Liang Xiong Huang-Tao guan Family Planning Research Institute Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China College of Informatics Huazhong Agricultural University Wuhan 430070 China Department of Venereology Wuhan Institute of Dermatology and Venereology Wuhan 430031 China Reproductive Medicine Center Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Hubei Province Human Sperm Bank Wuhan 430030 China

The present study aims to analyze sperm concentration trends among young and healthy Chinese adults in Wuhan, Central China, from 2010 to 2015. Semen analysis data from 9357 participants were collected and analyzed using a general linear model and the Cochran-Armitage trend test. A significant decline was observed in sperm concentration （β [standard deviation]： -1.53 [0.16]; P 〈 0.001）. In addition, a decline in sperm density was observed by stratifying student versus nonstudent sperm donors and by analyzing the year of birth or birth year cohort of the participants. Furthermore, the percentage of participants with sperm densities of over 40×10^6 ml^-1 significantly decreased with year. Notably, a dramatic decline in sperm density was recorded over the first 5 years of study.

关键词： healthy men semen concentration sperm donors temporal trends