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Discrete element modeling of sand behavior in a biaxial shear test

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第9期9卷 1176-1183页

作者： zhi-yi huang Zhong-xuan YANG Zhen-yu WANG Department of Civil Engineering Zhejiang University Hangzhou 310027 China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University Hangzhou 310027 China Department of Civil Engineering The University of Hong Kong Hong Kong China

The mechanical behavior of sand is very complex, and depends on factors including confining pressure, density, and drainage condition. A soil mass can be contractive or dilative when subjected to shear loading, and eventually reaches an ultimate state, referred to as the critical state in soil mechanics. Conventional approach to explore the mechanical behavior of sand mainly relies on the experimental tests in laboratory. This paper gives an alternative view to this subject using discrete element method (DEM), which has attracted much attention in recent years. The implementation of the DEM is carried out by a series of numerical tests on granular assemblies with varying initial densities and confining pressures, under different test configurations. The results demonstrate that such numerical simulations can produce correct responses of the sand behavior in general, including the critical state response, as compared to experimental observations. In addition, the DEM can further provide details of the microstructure evolutions during shearing processes, and the resulting induced anisotropy can be fully captured and quantified in the particle scale.

关键词： Granular soil behavior Critical state Microstructure Discrete element method (DEM)

Micromechanics-based analysis for predicting asphalt concrete modulus

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第6期11卷 415-424页

作者： Xing-yi ZHU zhi-yi huang Zhong-xuan YANG Wei-qiu CHEN Department of Civil Engineering Zhejiang University Hangzhou 310058 China Department of Engineering Mechanics Zhejiang University Hangzhou 310027 China

The elastic modulus of asphalt concrete(AC) is an important material parameter for pavement *** prediction and determination of elastic modulus,however,largely depends on laboratory tests which cannot reflect explicitly the influence of the microstructure of *** this end,a micromechanical model based on stepping scheme is *** is given to the influence of interfacial debonding and interlocking effect between the aggregates and asphalt mastic using the concept of effective *** on asphalt mixture with various microstructures are conducted to verify the proposed *** is shown that the prediction is generally in agreement with experimental *** affecting the elastic modulus of AC are also discussed in light of the proposed method.

关键词： Asphalt concrete(AC) Micromechanics Microstructure Effective bonding Optimum design Elastic modulus

Car-following theory of steady-state traffic flow using time-to-collision

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第8期12卷 645-654页

作者： Sheng JIN zhi-yi huang Peng-fei TAO Dian-hai WANG College of Civil Engineering and Architecture Zhejiang University Hangzhou 310058 China College of Traffic and Transportation Jilin University Changchun 130022 China

The conventional car-following theory is based on the assumption that vehicles will travel along the center line of lanes. However, according to the field survey data, in complex traffic conditions, a lateral separation between the leader and the follower frequently occurs. Accordingly, by taking lateral separation into account, we redefined the equation of time-to-collision (TTC) using visual angle information. Based on the stimulus-response framework, TTC was introduced into the basic General Motors (GM) model as a stimulus, and a non-lane-based car-following model of steady-state traffic flow was developed. The property of flow-density relationship was further investigated after integrating the proposed car-following model with different parameters. The results imply that the property of steady-state traffic flow and the capacity of each lane are highly relevant to the microscopic staggered car-following behavior, and the proposed model significantly enhances the practicality of the human driving behavior model.

关键词： Non-lane-based Visual angle Time-to-collision(TTC) Flow-density curve

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小夹角分叉隧道分流局部损失模型（英文）

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2019年第1期20卷 21-35页

作者： Xin ZHANG Tian-hang ZHANG Yun-ge HOU Kai ZHU zhi-yi huang Ke WU College of Civil Engineering and Architecture Zhejiang University School of Electronic Engineering Xi'an Shiyou University Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province College of Quality and Safety Engineering China Jiliang University

目的:掌握分叉隧道的空气流动特征与阻力损失特性是进行分叉隧道通风设计和控制的关键。本文旨在探讨小角度分叉结构中的流动特征及局部损失机制,并基于流动分离机制构建可供设计使用的分叉隧道分流局部损失系数的理论公式。创新点:1.... 详细信息

目的:掌握分叉隧道的空气流动特征与阻力损失特性是进行分叉隧道通风设计和控制的关键。本文旨在探讨小角度分叉结构中的流动特征及局部损失机制,并基于流动分离机制构建可供设计使用的分叉隧道分流局部损失系数的理论公式。创新点:1.揭示气流在小角度分叉结构中的流动分离特征及损失机制;2.提出流向偏转角假设,建立可供设计使用的分叉隧道分流局部损失预测模型。方法:1.通过数值模拟,获得隧道分叉处的流动特征(图5、6a和6d),以及分流局部损失系数随分流比及夹角的变化规律(图6b和6c);2.通过理论推导,构建小夹角分叉结构的分流局部损失系数预测公式(公式(18)和(21));3.通过现场实测,验证预测公式的可靠性(图15)。结论:1.空气在隧道分叉处的分流将导致流速和流向的变化;当分流比β较小时,流动分离出现在靠近分叉点一侧的主线边壁和远离分叉点一侧的匝道边壁;当β较大时,流动分离出现在远离分叉点一侧的主线边壁和靠近分叉点一侧的匝道边壁。2.当分流后主线与匝道的流量比q等于两者的面积比?时,主线及匝道的分流局部损失系数ξ12和ξ13最小;当q>?时,ξ12和ξ13均随β的增大而减小,且ξ13随着θ的增大而增大;当q

关键词：分叉隧道分流局部损失机制流动分离特征计算流体动力学理论公式

Riemannian Manifolds and representations of vertex operator algebras

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Riemannian Manifolds and representations of vertex operator ...

Overexpression of Tau Rescues Nogo-66-Induced Neurite Outgrowth Inhibition In Vitro

2011 Nanjing Conference on Metric Geometry and Applications in Memory of Professor Jianguo Cao

作者： yi-zhi huang(Rutgers University,USA)

Conjectures by physicists on nonlinear sigma-models are one of the most influential source of inspirations and motivations for many recent works in *** nonlinear sigma-models are still not mathematically constructed.I will review some of the attempts to construct such theories and discuss why they do not give the correct theories.I will also propose a program to give such a construction based on my recent work on representations of vertex operator algebras that are not necessarily semisimple.

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来源： cnki会议评论

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Neuroscience Bulletin 2016年第6期32卷 577-584页

作者： Yu-Chao Zuo Hong-Lian Li Nan-Xiang Xiong Jian-ying Shen yi-zhi huang Peng Fu Hong-Yang Zhao Department of Neurosurgery Union Hospital.Tongji Medical CollegeHuazhong University of Science and Technology Department of Neurosurgery The First Affiliated Hospital of Zhengzhou University Department of Anatomy Tongji Medical CollegeHuazhong University of Science and Technology

Abstract Nogo-66 plays a central role in the myelin- mediated inhibition of neurite outgrowth. Tau is a micro- tubule-associated protein involved in microtubule assembly and stabilization. It remains unverified whether tau inter- acts directly with growth factor receptors, or engages in cross-talk with regeneration inhibitors like Nogo-66. Here, we report that plasmid overexpression of tau significantly elevated the protein levels of total tau, phosphorylated tau, and microtubule-affinity regulating kinase （MARK）. Nogo- 66 transiently elevated the total tau protein level and per- sistently reduced the level of p-s262 tau （tau phosphory- lated at serine 262）, whereas it had little influence on the level of p-T205 tau （tau phosphorylated at threonine 205）. Nogo-66 significantly decreased the protein level of MARK. Hymenialdisine, an inhibitor of MARK, signifi- cantly reduced the level of p-S262 tau. Overexpression of tau rescued the Nogo-66-induced inhibition of neurite outgrowth in neuroblastoma cortical neurons. However, 2a （N2a） cells and primary concomitant inhibition ofMARK abolished the rescue of neurite outgrowth by tan in N2a cells. We conclude that dephosphorylation of tau at S262 is able to regulate Nogo-66 signaling, and that overexpression of tau can rescue the Nogo-66-induced inhibition of neurite outgrowth in vitro.

关键词： Neurite outgrowth Myelin inhibitor Microtubule-associated protein Phosphorylation

小额贷款公司试点实施的预期作用及个人建议——基于对浙江企业的实证研究

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特区经济 2009年第6期 289-291页

作者：张芝露黄燚涛西南财经大学四川成都611130

浙江企业作为全国中小企业发展的一个缩影,其经济发展具有一定的典型性。本文以浙江为例,通过收集其主要产业集群城市企业的生产数据,运用Cobb-Douglas生产函数模型和索洛增长速度方程进行生产函数和技术进步测算,得出小额贷款公司试点... 详细信息

浙江企业作为全国中小企业发展的一个缩影,其经济发展具有一定的典型性。本文以浙江为例,通过收集其主要产业集群城市企业的生产数据,运用Cobb-Douglas生产函数模型和索洛增长速度方程进行生产函数和技术进步测算,得出小额贷款公司试点实施的必要性、预期作用及对贷款业务风险管理的个人建议。

关键词：增长方式 Cobb-Douglas生产函数模型索洛增长速度方程风险管理

Car-following theory of steady-state traffic flow using time-to-collision

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第8期 632-632页

作者： Sheng JIN,zhi-yi huang,Peng-fei TAO,Dian-hai WANG

Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2011, Vol. 12, No. 8, P.645-654

关键词： time Car-following theory of steady-state traffic flow using time-to-collision flow

Car-following theory of steady-state traffic flow using time-to-collision

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 243-243页

作者： Sheng Jin zhi-yi huang Peng-fei Tao Dian-hai Wang Journal of Zhejiang University-SCIENCE A (Appfied Physics & Engineering)

The conventional car-following theory is based on the assumption that vehicles will travel along the center line of lanes. However, according to the field survey data, in complex traffic conditions, a lateral separation between the leader and the follower frequently occurs. Accordingly, by taking lateral separation into account, we redefined the equation of time-to-collision （TTC） using visual angle information. Based on the stimulus-response framework, TTC was introduced into the basic General Motors （GM） model as a stimulus, and a non-lane-based car-following model of steady-state traffic flow was developed. The property of flow-density relationship was further investigated after integrating the proposed car-following model with different parameters. The results imply that the property of steady-state traffic flow and the capacity of each lane are highly relevant to the mi- croscopic staggered car-following behavior, and the proposed model significantly enhances the practicality of the human driving behavior model.

关键词：通用汽车公司流量模型碰撞时间碰撞理论稳态跟车模型行为模型调查数据