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A theoretical model for the estimation of maximum impact force from a rockfall based on contact theory

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Journal of Mountain Science 2018年第2期15卷 430-443页

作者： ZHANG shi-lin YANG Xing-guo ZHOU Jia-wen State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University College of Water Resource and Hydropower Sichuan University

Rockfall poses a great threat to buildings and personal security. To understand the dynamic characteristics of rockfalls is a prerequisite for disaster prevention and assessment. Models for rockfalls in different forms are established based on the theory of rigid body motion. The equivalent velocity considering the rotational effect is determined by the energy ratio. Besides, considering plastic deformation and nonlinear hardening, the maximum impact force is estimated based on the Hertz contact theory. Then, a case study is carried out to illustrate the applicability of the model and sensitive analyses on some affecting parameters are also made. Calculation results show that the maximum impact force increases with the increasing of incident velocity, angle and slope gradient reflected by the changing of energy ratio. Moreover, the model for the estimation of maximum impact force is validated by two different scales of experiments and compared with other theoretical models. Simulated maximum impact forces agree well with the experiments.

关键词： RockfaU Motion characteristics Contacttheory Maximum impact force

Anorectal Malignant Melanoma：Diagnosis and Treatment of 42 Cases

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Chinese Journal of Cancer Research 2010年第3期22卷 176-180页

作者： Xiao-bin Li lin shi Shuang-min Zhang Department of General Surgery Peking Union Medical College Hospital Peking UnionMedical College Chinese Academy of Medical Sciences Beijing 100730 China Department of General Surgery Haidian Hospital Beijing 100080 China

Objective：Anorectal malignant melanoma（AMM） is a rare and aggressive malignant tumor,and its treatment still *** study was to investigate and summarize our experience on diagnosis,treatment and misdiagnosis of ***：From August 1980 to December 2009,42 patients with AMM were treated in our *** clinical data of those patients were retrospectively analyzed,including the major symptoms,treatment and *** immunophenotyping analyses using antibodies to S-100 protein,HMB-45 reactive antigen and vimentin were performed in 22 ***：The major complaints among the 42 cases were hematochezia（23/42,55.0%）,anal masses（12/42,28.6%）,changes in stool character（4/42,9.5%）,and anal tenesmus or pain（3/42,7.1%）.The misdiagnosis rate was 62%（26/42）,the most common misdiagnosis consisted of hemorrhoid（9/26,34.6%）,polyps（11/26,42.3%） and rectal cancer（6/26,23.1%）.28 cases underwent abdominoperineal resection,10 underwent local wide excision,3 underwent palliative operation,and 1 with no *** surgery,15 patients underwent radiotherapy,21 underwent chemotherapy and 8 were treated with both.22 cases deceased within 1 year,11 within 2 years,5 within 3 years and 1 within 4 *** median survival time was 11 months,with the longest of 45 *** immunohistochemical findings revealed that the S-100 protein was present in all 22 cases（100%）,HMB-45 was stained in 19 of 22（86.4%） and vimentin in 21 of 22（95.5%）.Conclusion：AMM is a rare disease with a poor prognosis and with an aptitude of being *** is the most common *** staining is conducive to the diagnosis of *** is the major treatment,the operation type should be individualized.

关键词： Anorectal Melanoma Diagnosis Treatment

Melnikov Method and Detection of Chaos for Non-smooth Systems

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Acta Mathematicae Applicatae Sinica 2013年第4期29卷 881-896页

作者： lin-song shi Yong-kui ZOU Tassilo Küpper Department of Mathematics Tsinghua University Departmentt of Mathematics Jilin University Mathematics Institute Univeristy of Cologne

We extend the Melnikov method to non-smooth dynamical systems to study the global behavior near a non-smooth homoclinic orbit under small time-periodic perturbations. The definition and an explicit expression for the extended Melnikov function are given and applied to determine the appearance of transversal homoclinic orbits and chaos. In addition to the standard integral part, the extended Melnikov function contains an extra term which reflects the change of the vector field at the discontinuity. An example is discussed to illustrate the results.

关键词： Chaos non-smooth dynamical system Melnikov method homoclinic orbit

Frontal Crash Analysis of a Fully Detailed Car Model Based on Finite Element Method

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上海交通大学学报 2004年第Z2期38卷 136-141页

作者： Han Shan-ling Zhu Ping lin Zhong-Qin shi Yu-Liang School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China

This paper sets up a highly detailed finite element model of a car for frontal crashworthiness applications, and then explains the characteristics of it. The geometry model is preprocessed by Hypermesh software. The finite element method solver program selected for the simulation is LS-DYNA. After the crash simulation is carefully analyzed, the frontal crash experiment is aimed to validate the finite element model. The simulation results are basically in agreement with the experimental results. The validation of the finite element model is crucial for the further research in optimization of the automotive structure or lightweighting of the vehicle.

关键词： finite element method frontal crash LS-DYNA

QCD Axial Anomaly Enhances theηη'Decay of the Hybrid Candidateη1(1855)

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维普期刊数据库

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Chinese Physics Letters 2022年第5期39卷 29-35页

作者： Hua-Xing Chen Niu Su shi-lin Zhu School of Physics Southeast UniversityNanjing 210094China School of Physics and Center of High Energy Physics Peking UniversityBeijing 100871China

We study the hybrid mesons with the exotic quantum number I^(G)J^(PG)=0+1-+and investigate their decays into theηη’,a1(1260)π,f1(1285)η,f1(1420)η,K*(892)■,K1(1270)■,and K1(1400)■*** is found that the QCD axial anomaly enhances the decay width of theηη’channel although this mode is strongly suppressed by the small p-wave phase *** results support the interpretation of theη1(1855)recently observed by BESⅢas the ssg hybrid meson of I^(G)J^(PC)=0^(+)1^(-+).The QCD axial anomaly ensures theηη’decay mode to be a characteristic signal of the hybrid nature of theη1(1855).

关键词： BESⅢ QCD mode

Group tracking control of second-order multi-agent systems 36

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Group tracking control of second-order multi-agent systems

A UNIFIED EXTENDING METHOD FOR CONTENT-IGNORANT WEB PAGE CLUSTERING

第36届中国控制会议

作者： lin shi Qing Cui Dongmei Xie Department of Mathematics Tianjin University

ISBN: (纸本)9781538629185

This paper focuses on studying the group consensus tracking issue of discrete time second-order multi-agent systems（MASs） under directed fixed and Markovian switching topologies, respectively. For MASs with m leaders, we first introduce a method to divide the whole MASs into m subgroups. Based on the subgroup-divided method, the condensation directed graph G of the communication topology of the whole MASs becomes a directed acyclic graph（DAG）. Then, for MASs with fixed/Markovian switching topology, some sufficient/necessary and sufficient group consensus tracking criteria are established.

关键词： Multi-agent systems(MASs) subgroup-divided method group tracking Markovian switching topologies

来源： cnki会议评论

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cnki会议

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Journal of Electronics(China) 2010年第1期27卷 105-112页

作者： shi lin Chen Chen School of Aerospace Science and Engineering Beijing Institute of Technology Beijing 100081 China School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

The content-ignorant clustering method takes advantages in time complexity and space complexity than the content based *** this paper,the authors introduce a unified expanding method for content-ignorant web page clustering by mining the "click-through" log,which tries to solve the problem that the "click-through" log is *** relationship between two nodes which have been expanded is also defined and *** and experiment show that the performance of the new method has improved,by the comparison with the standard content-ignorant *** new method can also work without iterative clustering.

关键词： Web data mining Clustering Content-ignorant clustering

Adsorption of herring sperm DNA onto pine sawdust biochar:Thermodynamics and site energy distribution

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Frontiers of Environmental Science & Engineering 2022年第11期16卷 223-232页

作者： Mingyi Yang lin shi Di Zhang Zhaohui He Aiping Liang Xiao Sun Faculty of Environmental Science and Engineering Kunming University of Science and TechnologyKunming 650500China School of Resources and Environment Linyi UniversityLinyi 276005China Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control Kunming 650500China School of Environmental and Material Engineering Yantai UniversityYantai 264005China

Environmental deoxyribonucleic acid(eDNA),which includes antibiotic resistance genes,is ubiquitous in the *** interactions between eDNA and biochar,a promising material widely used in soil amendment and water treatment,greatly affect the environmental behavior of *** few experimental evidences are available yet,especially on the information of thermodynamics and energy distribution to explains the interactions between biochar and *** study investigated the adsorption of herring sperm DNA(hsDNA)on pine sawdust biochar,with a specific emphasis on the adsorption thermodynamics and site energy *** adsorption of hsDNA on biochar was enhanced by an increase in the pyrolysis and adsorption *** higher surface area,strongerπ−πinteraction,and weaker electrostatic repulsion between hsDNA and biochars prepared at high pyrolysis temperatures facilitated the adsorption of *** thermodynamics indicated that the adsorption of hsDNA on biochar was spontaneous and ***,higher temperature was beneficial for the adsorption of hsDNA on biochar;this was well explained by the increase in E*and F(E*)with the adsorption *** results are useful for evaluating the migration and transformation of eDNA in the presence of biochar.

关键词： Environmental deoxyribonucleic acid Antibiotic resistance genes Biochar Adsorption thermodynamics

Anharmonic multi-phonon nonradiative transition: A n ab initio calculation approach

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Science China(Physics,Mechanics & Astronomy) 2020年第7期63卷 97-103页

作者： Yao Xiao ZiWu Wang lin shi XiangWei Jiang ShuShen Li linWang Wang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology Department of PhysicsSchool of ScienceTianjin UniversityTianjin 300354China Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of SciencesSuzhou 215123China Materials Science Division Lawrence Berkeley National LaboratoryBerkeley 94720USA

Nonradiative carrier recombinations at deep centers in semiconductors are of great importance for both fundamental physics and device *** this article,we provide a revised analysis of Huang's original nonradiative multi-phonon(NMP)theory with ab initio ***,we confirmed at the first-principles level that Huang's concise formula gives the same results as the matrix-based formula,and that Huang's high-temperature formula provides an analytical expression for the coupling constant in Marcus ***,we correct for anharmonic effects by taking into account local phonon-mode variations for different charge states of a *** corrected capture rates for defects in GaN and SiC agree well with experiments.

关键词： multi-phonon transition nonradiative point defect anharmonic density-functional theory