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Stability analysis of slope in strain-softening soils using local arc-length solution scheme

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Journal of Mountain Science 2017年第1期14卷 175-187页

作者： wang xiang-rong rong Qi-guo SUN Shu-li wang Hui College of Engineering Peking University Graduate School AICES RWTH Aachen University

Soils with strain-softening behavior — manifesting as a reduction of strength with increasing plastic strain — are commonly found in the natural environment. For slopes in these soils,a progressive failure mechanism can occur due to a reduction of strength with increasing strain. Finite element method based numerical approaches have been widely performed for simulating such failure mechanism,owning to their ability for tracing the formation and development of the localized shear strain. However,the reliability of the currently used approaches are often affected by poor convergence or significant mesh-dependency,and their applicability is limited by the use of complicated soil models. This paper aims to overcome these limitations by developing a finite element approach using a local arc-length controlled iterative algorithm as the solution strategy. In the proposed finite element approach,the soils are simulated with an elastoplastic constitutive model in conjunction with the Mohr-Coulomb yield function. The strain-softening behavior is represented by a piece-wise linearrelationship between the Mohr-Coulomb strength parameters and the deviatoric plastic strain. To assess the reliability of the proposed finite element approach,comparisons of the numerical solutions obtained by different finite element methods and meshes with various qualities are presented. Moreover,a landslide triggered by excavation in a real expressway construction project is analyzed by the presented finite element approach to demonstrate its applicability for practical engineering problems.

关键词： Strain-softening Progressive failure Slope stability Local arc-length scheme Numerical simulation

A Possible Minimum Toy Model with Negative Differential Capacitance for Self-sustained Current Oscillation

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Communications in Theoretical Physics 2007年第5期47卷 949-954页

作者： XIONG Gang SUN Zhou-Zhou wang xiang-rong Physics Department Beijing Normal University Beijing 100875 China Physics Department The Hong Kong University of Science and Technology Clear Water Bay Hong Kong SAR China

We generalize a simple model for superlattices to include the effect of differential capacitance. It is shown that the model always has a stable steady-state solution （SSS） if all differential capacitances are positive. On the other hand, when negative differential capacitance is included, the model can have no stable SSS and be in a self-sustained current oscillation behavior. Therefore, we find a possible minimum toy model with both negative differential resistance and negative differential capacitance which can include the phenomena of both self-sustained current oscillation and I-V oscillation of stable SSSs.

关键词： self-sustained current oscillation negative differential capacitance

Impact of STAT4 gene silencing on the expression profile of proteins in EL-4 cells

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Chinese Science Bulletin 2009年第18期54卷 3265-3270页

作者： WEI XiaoLi NI Hong wang QingShan xiang rong wang Yue School of Medicine Nankai University Tianjin 3000-71 China

The signal transducers and activators of transcription (STATs) have diverse biological functions and are involved in cell differentiation, proliferation, development, apoptosis and inflammation. Several constitutively activated STATs have been observed in a wide variety of human cancer cell lines and primary tumor cells, including blood malignancies and solid neoplasias. Although regulatory T (Treg) cells induce immune tolerance by suppressing host immune responses against selfor nonself-antigens, thus playing critical roles in preventing autoimmune diseases, they might inhibit antitumor im-munity and promote tumor growth. Our previous findings suggest that the supernatant from STAT4silenced tumor cell culture can significantly increase the ratio of CD4+ CD25+ Foxp3+ regulatory T cells among splenic cells in vitro, when compared to that from normal tumor cell culture. In the present study, we identified that the mouse lymphoma cell line EL-4 expressed a high level of STAT4, and silencing of STAT4 by siRNA did not change the expression levels of TGF-β and IL-10 in EL-4 cells. Two-dimensional electrophoresis was conducted to examine the difference of expression profiles of proteins between normal and STAT4-silenced EL4 cells. Some of the protein which has been changed may induce CD4+ CD25+ Foxp3+ regulatory T cells in vitro.

关键词：细胞分化细胞蛋白表达谱基因沉默转录激活因子转化生长因子肿瘤细胞发光

Quantum information processing and metrology with color centers in diamonds

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Frontiers of physics 2014年第5期9卷 587-597页

作者： Jing-Wei Zhou Peng-Fei wang Fa-Zhan Shi Pu Huang Xi Kong xiang-Kun Xu Qi Zhang Zi-xiang wang Xing rong Jiang-Feng Du Hefei National Laboratory for Physics Sciences at the Microscale and Department of Modern Physics University of Science and Technology of China Hefei 230026 China

The Nitrogen Vacancy （NV） center is becoming a promising qubit for quantum information processing. The defect has a long coherence time at room temperature and it allows spin state initialized and read out by laser and manipulated by microwave pulses. It has been utilized as a ultra sensi- tive probe for magnetic fields and remote spins as well. Here, we review the recent progresses in experimental demonstrations based on NV centers. We first introduce our work on implementation of the Deutsch- Jozsa algorithm with a single electronic spin in diamond. Then the quantum nature of the bath around the center spin is revealed and continuous wave dynamical decoupling has been demonstrated. By applying dynamical decoupling, a multi-pass quantum metrology protocol is realized to enhance phase estimation. In the final, we demonstrated NV center can be regarded as a ultra-sensitive sensor spin to implement nuclear magnetic resonance （NMR） imaging at nanoscale.

关键词： quantum information processing and metrology Nitrogen Vacancy center phase estimation dynamical deeoupling single spin detection

Isolation and algae-lysing characteristics of the algicidal bacterium B5

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Journal of Environmental Sciences 2007年第11期19卷 1336-1340页

作者： MU Rui-min FAN Zheng-qiu PEI Hai-yan YUAN Xue-liang Liu Si-xiu wang xiang-rong Department of Environmental Science and Engineering Fudan University Shanghai 200433 China College of Environmental Science and Engineering Ocean University of China Qingdao 266003 China Environmental Research Institute Shandong University Jinan 250100 China

Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that：（1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.

关键词： algicidal bacteria water blooms algae-lysing characteristic 16S rDNA Bacillusfusiformis

The surface treatment on oxide film of pure titanium Part *** of anodic oxide film

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口腔医学研究 2007年第1期23卷 60-62页

作者： wang Ge Cheng xiang - rong Department of Prosthodonties School of Stomatology Wuhan University 430070 Wuhan People＇s Republic of China

目的:用有氧加热处理阳极氧化膜以进一步提高纯钛的耐腐蚀性。材料和方法:6片直径9 mm厚2 mm的纯钛片经阳极氧化处理24 v 10 min后置于烤瓷炉,在有氧环境中加热至400℃(A)、420℃(B)、450℃(C)、500℃(D)、700℃(E)、915℃(F),分别维持4... 详细信息

目的:用有氧加热处理阳极氧化膜以进一步提高纯钛的耐腐蚀性。材料和方法:6片直径9 mm厚2 mm的纯钛片经阳极氧化处理24 v 10 min后置于烤瓷炉,在有氧环境中加热至400℃(A)、420℃(B)、450℃(C)、500℃(D)、700℃(E)、915℃(F),分别维持40 min,用X线衍射和电化学法检测氧化膜的微观结构和耐腐蚀性,再将样本A和E在上述条件下分别在加热40 min,重复以上检测。结果:加热400℃维持40 min的阳极氧化样品的耐腐蚀性最好,过高的加热温度和加热时间都会破坏氧化膜的耐腐蚀性。结论:阳极氧化结合有氧加热处理是一种较好的提高纯钛氧化膜的耐腐蚀性的方法。

关键词：阳极氧化有氧加热微观结构耐腐蚀性

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城市绿地的三维生态特征及其生态功能

中国环境科学 2001年第2期21卷 101-104页

作者：张浩王祥荣华东师范大学环境科学系上海200062 复旦大学环境科学与工程系上海200433

城市绿地是城市生态系统中具有负反馈调节功能的重要组分,能在一定程度上发挥各种生态功能,维持城市生态系统的平衡.绿地在抗逆性和对环境的改造能力方面也存在着很大的差异,这可归结为绿地的三维生态特征差异所致.在对上海市区绿地生... 详细信息

城市绿地是城市生态系统中具有负反馈调节功能的重要组分,能在一定程度上发挥各种生态功能,维持城市生态系统的平衡.绿地在抗逆性和对环境的改造能力方面也存在着很大的差异,这可归结为绿地的三维生态特征差异所致.在对上海市区绿地生态效应实测数据分析的基础上,探讨了城市绿地三维生态特征对绿地生态功能的影响.

关键词：城市绿地三维生态特征生态功能城市生态系统

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三峡成库前后沿江山水景观空间视觉特征比较

上海交通大学学报 2007年第5期41卷 818-824,829页

作者：汤晓敏王祥荣复旦大学环境科学与工程系

以景观空间尺度规律与人的视觉规律为指导,基于RS、GIS以及AutoCAD技术,从江面视点出发,通过测定山水景观视觉空间断面的宽高比,辨识长江三峡库区(重庆段)沿江山水景观视觉空间的类型.从空间视域、视距与观景者视觉接收后所产生的心理... 详细信息

以景观空间尺度规律与人的视觉规律为指导,基于RS、GIS以及AutoCAD技术,从江面视点出发,通过测定山水景观视觉空间断面的宽高比,辨识长江三峡库区(重庆段)沿江山水景观视觉空间的类型.从空间视域、视距与观景者视觉接收后所产生的心理体验等几个方面,比较分析了长江在三峡成库前的常年洪水位、成库后的145与175 m水位下沿江景观视觉特征的变化.结果表明:①沿江山水构建出夹景、敞景、框景3种视觉空间类型;②长江水位的抬升对沿江山水景观视觉空间的总体特征影响不大,整体山水景观空间格局不变,夹景空间峡感犹存,雄、奇、幽的三峡风貌基本不变,但高峡平湖景观取代滩多水急的风光,两岸支流可达性增强,消落带由夏水冬陆型转为冬水夏陆型.对此提出了相应的景观规划与建设的对策建议,以期对三峡工程的景观视觉质量影响评价及景观规划建设提供科学依据.

关键词：三峡库区景观视觉空间视距视域视角

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确定总应变寿命方程中指数的一种方法

航空动力学报 2017年第1期32卷 105-113页

作者：刘香王延荣田爱梅北京航空航天大学能源与动力工程学院北京100191 先进航空发动机协同创新中心北京100191 北京航空航天大学宇航学院北京100191

在由材料的单调拉伸强度极限和断面收缩率确定总应变寿命方程中疲劳强度系数和疲劳延性系数的基础上,考查了利用材料在两个不同应力幅下的疲劳试验数据和单调拉伸延伸率来确定总应变寿命方程中疲劳强度指数和疲劳延性指数的一种方法,给... 详细信息

在由材料的单调拉伸强度极限和断面收缩率确定总应变寿命方程中疲劳强度系数和疲劳延性系数的基础上,考查了利用材料在两个不同应力幅下的疲劳试验数据和单调拉伸延伸率来确定总应变寿命方程中疲劳强度指数和疲劳延性指数的一种方法,给出了只需较少的疲劳试验数据和单调拉伸力学性能参数即可确定材料的总应变寿命方程中全部4个参数的分析流程,并利用航空发动机中常用的钛合金和镍基合金材料的疲劳试验数据对该方法进行了验证,结果表明该方法所确定的总应变寿命方程对所考查的材料大多数情形的疲劳寿命预测结果较为理想,基本在3倍分散带以内.

关键词：总应变寿命方程疲劳强度系数疲劳延性系数疲劳强度指数疲劳延性指数寿命预测