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Fuzzy finite difference method for heat conduction analysis with uncertain parameters

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Acta Mechanica Sinica 2014年第3期30卷 383-390页

作者： Chong Wang zhi-Ping qiu Institute of Solid Mechanics Beihang University

A new numerical technique named as fuzzy finite difference method is proposed to solve the heat conduction problems with fuzzy uncertainties in both the phys- ical parameters and initial/boundary conditions. In virtue of the level-cut method, the difference discrete equations with fuzzy parameters are equivalently transformed into groups of interval equations. New stability analysis theory suited to fuzzy difference schemes is developed. Based on the parameter perturbation method, the interval ranges of the uncertain temperature field can be approximately predicted. Subsequently, fuzzy solutions to the original difference equations are obtained by the fuzzy resolution theorem. Two numerical examples are given to demonstrate the feasibility and efficiency of the presented method for solving both steady-state and transient heat conduction problems.

关键词： Heat conduction Fuzzy uncertainties Finitedifference method Parameter perturbation Stability analysis

Interval finite difference method for steady-state temperature field prediction with interval parameters

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Acta Mechanica Sinica 2014年第2期30卷 161-166页

作者： Chong Wang zhi-Ping qiu Institute of Solid Mechanics Beihang University

A new numerical technique named interval finite difference method is proposed for the steady-state temperature field prediction with uncertainties in both physical parameters and boundary conditions. Interval variables are used to quantitatively describe the uncertain parameters with limited information. Based on different Taylor and Neumann series, two kinds of parameter perturbation methods are presented to approximately yield the ranges of the uncertain temperature field. By comparing the results with traditional Monte Carlo simulation, a numerical example is given to demonstrate the feasibility and effectiveness of the proposed method for solving steady-state heat conduction problem with uncertain-but-bounded parameters.

关键词： Steady-state heat conduction Interval finite dif-ference Temperature field prediction Parameter perturba-tion method Interval uncertainties

Fatigue reliability based on residual strength model with hybrid uncertain parameters

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Acta Mechanica Sinica 2012年第1期28卷 112-117页

作者： Jun Wang zhi-Ping qiu Institute of Solid Mechanics Beihang University100191 BeijingChina

The aim of this paper is to evaluate the fatigue reliability with hybrid uncertain parameters based on a residual strength model. By solving the non-probabilistic setbased reliability problem and analyzing the reliability with randomness, the fatigue reliability with hybrid parameters can be obtained. The presented hybrid model can adequately consider all uncertainties affecting the fatigue reliability with hybrid uncertain parameters. A comparison among the presented hybrid model, non-probabilistic set-theoretic model and the conventional random model is made through two typical numerical examples. The results show that the presented hybrid model, which can ensure structural security, is effective and practical.

关键词： Fatigue reliability Residual strength Ran- dom model Non-probabilistic set-theoretic model Hybrid model

Non-probabilistic information fusion technique for structural damage identification based on measured dynamic data with uncertainty

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Acta Mechanica Sinica 2013年第2期29卷 202-210页

作者： Xiao-Jun Wang Chen Yang zhi-Ping qiu Institute of Solid Mechanics Beihang University

Based on measured natural frequencies and acceleration responses,a non-probabilistic information fusion technique is proposed for the structural damage detection by adopting the set-membership identification（SMI） and twostep model updating *** to the insufficiency and uncertainty of information obtained from measurements,the uncertain problem of damage identification is addressed with interval variables in this *** on the first-order Taylor series expansion,the interval bounds of the elemental stiffness parameters in undamaged and damaged models are estimated,*** possibility of damage existence（PoDE） in elements is proposed as the quantitative measure of structural damage probability,which is more reasonable in the condition of insufficient measurement *** comparison with the identification method based on a single kind of information,the SMI method will improve the accuracy in damage identification,which reflects the information fusion concept based on the non-probabilistic set.A numerical example is performed to demonstrate the feasibility and effectiveness of the proposed technique.

关键词： Damage identification·Information fusion technique·Set-membership identification(SMI)·Uncertainty·Interval analysis method

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甲烷在钠基蒙脱土吸附的第一性原理研究

原子与分子物理学报 2025年第2期42卷 8-14页

作者：方志杰李博宋昌辉刘美玲何秋芝刘翔莫曼广西科技大学电子工程学院柳州545006 广西科技大学土木建筑工程学院柳州545006 广西科技大学医学部柳州545006

随着经济的发展,能源需求日益增加,为了弥补国内少油缺气短板,页岩气的开发成为近期新能源的热点,探索页岩气储存规律是页岩气能源开发的关键所在.本文采用密度泛函理论的第一性原理方法,计算甲烷(CH_(4))在钠基蒙脱土表面和层间的吸附... 详细信息

随着经济的发展,能源需求日益增加,为了弥补国内少油缺气短板,页岩气的开发成为近期新能源的热点,探索页岩气储存规律是页岩气能源开发的关键所在.本文采用密度泛函理论的第一性原理方法,计算甲烷(CH_(4))在钠基蒙脱土表面和层间的吸附能,对比吸附前后的态密度和物理结构以及差分电荷密度.结果表明:钠基蒙脱土表面吸附中,甲烷最佳选择是桥位,吸附能为-0.08eV,被吸附后甲烷的键长和键角变化率均小于0.96%.层间吸附中,伴随着甲烷吸附量增加,纳基蒙脱土体积向c轴方向线性增加,a、b轴方向则变化不大.总态密度随着吸附量的增加,总能级数量也增加,甲烷分子的分波态密度峰向低能级移动.本文的研究成果,从原子角度分析了甲烷在蒙脱石表面以及层间的吸附能力,为解释页岩气在页岩储存规律提供理论依据.

关键词：钠基蒙脱土第一性原理甲烷吸附态密度

Parametric formulae for axial stiffness of CHS X-joints subjected to brace axial tension

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第2期12卷 121-130页

作者： Guo-zhi qiu Jing-hai GONG Jin-cheng ZHAO Department of Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China

Recent research has shown that circular hollow section(CHS) joints may exhibit non-rigid behavior under axial load or bending. The non-rigid behavior significantly affects the mechanical performance of structures. This paper is concerned with the parametric formulae for predicting axial stiffness of CHS X-joints while braces are in tension. The factors influencing the axial stiffness of CHS X-joints under brace axial tension are investigated,including the joint geometric parameters,the axial force of the chord,and bending moments of braces in two directions,etc. Effects of various parameters on axial stiffness of CHS X-joints are examined by systematic single-parameter nonlinear analysis using shell finite element methods. The analysis is implemented in a finite element code,ANSYS. The observed trends form the basis of the formulae for calculating the joint axial stiffness under brace axial tension by multivariate regression technique. In order to simplify the formulae,two non-dimensional variables are introduced. The proposed formulae can be used to calculate the joint axial stiffness in the design of single-layer steel tubular structures.

关键词： Joint stiffness Brace tension Parametric analysis Stiffness formula

Silicate-doped hydroxyapatite and its promotive effect on bone mineralization

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Frontiers of Materials Science 2013年第1期7卷 40-50页

作者： zhi-Ye qiu In-Sup NOH Sheng-Min ZHANG Advanced Biomaterials and Tissue Engineering Center Huazhong University of Science and Technology Wuhan 430074 China Department of Materials Science and Engineering Tsinghua University Beijing 100084 China Department of Chemical and Biological Engineering Seoul National University of Science and Technology Seou1139743 Korea

Bone defect is one of the most common diseases in clinic. Existing therapeutic approaches have encountered many problems, such as lack of autogenous allogeneic bone and immunological rejection to allogeneic implant. Synthetic hydroxyapatite (HA) provided solutions for bone repair, since the HA is the main inorganic component of animals’ bone. However, HA has good biocompatibility, but does not possess osteogenic capability, which is of significance for modern bone repair materials. Si is an essential trace element in bone tissue, and it has been demonstrated to be able to promote bone formation. Therefore, silicate-doped hydroxyapatite (Si-HA) may serve as a promising material for bone repair, and promote bone regeneration in the repair. The current review discusses development of Si-HA, focusing on its preparation and characterization, in vitro and in vivo evaluations of the material, positive effect of Si-HA on promoting bone formation in clinical applications, and molecular mechanism investigation of such promotive effect.

关键词： silicate-doped hydroxyapatite (Si-HA) osteogenesis collagen biosynthesis bone mineralization

Biomaterials for reconstruction of cranial defects

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Frontiers of Materials Science 2015年第4期9卷 346-354页

作者： Tao SONG zhi-Ye qiu Fu-Zhai CUI Department of Neurosurgery Shandong Provincial Hospital Jinan 250021 China School of Materials Science and Engineering Tsinghua University Beijing 100084 China Beijing AIIgens Medical Science and Technology Co. Ltd. No.1 Disheng East Roacl Yizhuang Economic-and Technological Development Zone Beijing 100176 China

Reconstruction of cranial defect is commonly performed in neurosurgical operations. Many materials have been employed for repairing cranial defects. In this paper, materials used for cranioplasty, including autografts, allografts, and synthetic biomaterials are comprehensively reviewed. This paper also gives future perspective of the materials and development trend of manufacturing process for cranioplasty implants.

关键词： cranioplasty autograft allograft metallic material bioceramics mineralized collagen

Discovering API Directives from API Specifications with Text Classification

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Journal of Computer Science & Technology 2021年第4期36卷 922-943页

作者： Jing-Xuan Zhang Chuan-Qi Tao zhi-qiu Huang Xin Chen College of Compute Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Safety-Critical Software(Nanjing University of Aeronautics and Astronautics) Ministry of Industry and Information TechnologyNanjing 210016China Key Laboratory of Complex Systems Modeling and Simulation(Hangzhou Dianzi University) Ministry of Education Hangzhou 310018China School of Computer Science and Technology Hangzhou Dianzi UniversityHangzhou 310018China

Application programming interface(API)libraries are extensively used by *** correctly program with APIs and avoid bugs,developers shall pay attention to API directives,which illustrate the constraints of ***,API directives usually have diverse morphologies,making it time-consuming and error-prone for developers to discover all the relevant API *** this paper,we propose an approach leveraging text classification to discover API directives from API ***,given a set of training sentences in API specifications,our approach first characterizes each sentence by three groups of ***,to deal with the unequal distribution between API directives and non-directives,our approach employs an under-sampling strategy to split the imbalanced training set into several subsets and trains several *** a new sentence in an API specification,our approach synthesizes the trained classifiers to predict whether it is an API *** have evaluated our approach over a publicly available annotated API directive *** experimental results reveal that our approach achieves an F-measure value of up to 82.08%.In addition,our approach statistically outperforms the state-of-the-art approach by up to 29.67%in terms of F-measure.

关键词： Application programming interface(API)directive API specification imbalanced learning text classification