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Analysis on cohesive crack opening displacement considering the strain softening effect

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Science china(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2 & ZHAO Xiqiang3.1. Mechanics department, Shandong University of Technology, Zibo 255049, china 2. Civil engineering department, Dalian University of Technology, Dalian 116024, china 3. Mathematics department, Ocean University of china, qingdao 266071, china Mechanics department Shandong University of Technology Zibo China Civil engineering department Dalian University of Technology Dalian China Mathematics department Ocean University of China Qingdao China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

Construction and application of formal ontology for mine

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中国有色金属学会会刊：英文版 2011年第S3期21卷 577-582页

作者： CHENG Gang 1, 2, ZHANG Yin-ling1, 2, WANG Fei 1 ,2, ZHANG Zhen-hui 3. GUO Yu-xiang1, 2 1. Key Laboratory of Mine Spatial Information Technologies of State Bureau of Surveying and Mapping, Henan Polytechnic University, Jiaozuo 454003. china 2. School of Surveying and land Information engineering, Henan Polytechnic University, Jiaozuo 454003. china 3. {3. Branch of Naval Aeronautical engineering Institute, {3. 266041, china Key Laboratory of Mine Spatial Information Technologies of State Bureau of Surveying and Mapping Henan Polytechnic University Jiaozuo 454003 China School of Surveying and land Information engineering Henan Polytechnic University Jiaozuo 454003 China qingdao Branch of Naval Aeronautical engineering Institute Qingdao 266041 China

Digital mine is the only way for the development of mining industry in china. Due to lack of appropriate standards and norms, and different awareness in the field of digital mine among academia and industry insiders, the meaning for digital mine is still unclear. Starting from the nature of mining and removing of views of specialized fields, this paper constructs formal ontology for digital mine and proposes the four levels for it. The ontology clarifies the concept world for digital mine, defines the meaning of concepts and relations clearly, provides a reference for the standard construction for digital mine and provides a unified semantic framework for the integration of heterogeneous mine data. Meanwhile, it can provide formal reasoning knowledge for expert system of digital mine and improve the intelligence and automation while the machine automatically interpreting and processing mine spatial data.

关键词： Digital mine formalization ontology concept world semantic share

An Efficient Approach for Fuzzy Project Network Analysis

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Systems Science and Systems engineering 2002年第1期11卷 83-89页

作者： HU Jing-song department of Management Science & engineering, qingdao University,{3.,china department of Management Science & engineering Qingdao University Qingdao 266071 China

In this paper we present two-level linear programming method for determining latest dates and slack times in project network models with triangular fuzzy number or trapezoidal fuzzy number. Compared with the well-known fuzzy network techniques in literature, the approach always produces the meaningful latest dates and slack times. Practically we have generalized critical path method by accepting imprecise, fuzzy data for the duration of the activities.

关键词： network analysis fuzzy equations linear programming

Preparation, characterization, viscosity and thermal conductivity of CaCO_3.aqueous nanofluids

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Science china(Technological Sciences) 2010年第2期53卷 360-368页

作者： ZHU HaiTao1, LI ChangJiang2, WU DaXiong1, ZHANG CanYing1 & YIN YanSheng2 1 College of Materials Science and engineering, qingdao University of Science and Technology, qingdao 266042,{3. 2 department of Materials, Ocean University of{3., qingdao 266003.{3. College of Materials Science and engineering Qingdao University of Science and Technology Qingdao China department of Materials Ocean University of China Qingdao China

CaCO3.aqueous nanofluids were prepared by dispensing aqueous CaCO3.paste into distilled water under ultrasonic vibration. The actual microstructures of the CaCO3.nanofluids with different particle volume fractions were characterized by freeze etching replication transmission electron microscopy (FERTEM). Thermal conductivity and rheological behavior of the nanofluids were measured by standard analyzers. The results show that CaCO3.paste as raw material for nanofluids is advantageous to reducing aggregation of primary nanoparticles. The effective viscosities and effective thermal conductivities of the CaCO3.nanofluids are related to the aggregates of nanoparticles and can be well predicted by the modified Krieger & Dougherty formula and the modified Hamilton & Crosser model, respectively.

关键词： CaCO3 nanofluid thermal conductivity viscosity microstructure

Approximately optimal tracking control for discrete time-delay systems with disturbances

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Progress in Natural Science:Materials International 2008年第2期18卷 225-231页

作者： Gongyou Tang a,,Huiying Sun b,Haiping Pang c a College of Information Science and engineering,Ocean University of china,qingdao 266100,{3. b College of Information and electrical engineering,Shandong University of Science and Technology,qingdao 266510,{3. c College of Automation and Electronic engineering,qingdao University of Science and Technology,qingdao 266042,{3. College of Information Science and engineering Ocean University of China Qingdao 266100 China College of Information and electrical engineering Shandong University of Science and Technology Qingdao 266510 China College of Automation and Electronic engineering Qingdao University of Science and Technology Qingdao 266042 China

Optimal tracking control (OTC) for discrete time-delay systems affected by persistent disturbances with quadratic performance index is considered. By introducing a sensitivity parameter,the original OTC problem is transformed into a series of two-point boundary value (TPBV) problems without time-advance or time-delay terms. The obtained OTC law consists of analytic feedforward and feedback terms and a compensation term which is the sum of an infinite series of adjoint vectors. The analytic feedforward and feedback terms can be found by solving a Riccati matrix equation and two Stein matrix equations. The compensation term can be obtained by using an iteration formula of the adjoint vectors. Observers are constructed to make the approximate OTC law physically realizable. A simulation example shows that the approximate approach is effective in tracking the reference input and robust with respect to exogenous persistent disturbances.

关键词： Discrete systems Time-delay systems Disturbances Optimal control Tracking control

Symmetries and exact solutions of discrete nonconservative systems

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1699-1706页

作者： FU JingLi1,LI XiaoWei2,LI ChaoRong1,ZHAO WeiJia3.& CHEN BenYong4 1 Institute of Mathematical Physics,Zhejiang Sci-Tech University,Hangzhou 3.0018,china 2 department of Physics,Shangqiu Normal University,Shangqiu 476000,china 3.department of Mathematics,qingdao University,qingdao 266071,china 4 Faculty of Mechanical engineering & Automation,Zhejiang Sci-Tech University,Hangzhou 3.0018,china Institute of Mathematical Physics Zhejiang Sci-Tech University Hangzhou China department of Physics Shangqiu Normal University Shangqiu China department of Mathematics Qingdao University Qingdao China Faculty of Mechanical engineering & Automation Zhejiang Sci-Tech University Hangzhou China

Based on the property of the discrete model entirely inheriting the symmetry of the continuous system,we present a method to construct exact solutions with continuous groups of transformations in discrete nonconservative *** Noether's identity of the discrete nonconservative system is *** symmetric discrete Lagrangian and symmetric discrete nonconservative forces are defined for the *** quasi-extremal equations of discrete nonconservative systems are *** conserved quantities are derived with symmetries associated with the continuous *** have also found that the existence of the one-parameter symmetry group provides a reduction to a conserved quantity;but the existence of a two-parameter symmetry group makes it possible to obtain an exact solution for a discrete nonconservative *** examples are discussed to illustrate these results.

关键词： discrete nonconservative system symmetry conserved quantity quasi-extremal equation exact solution

The correlation of flare's location on solar disc and the sudden increase of total electron content

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Chinese Science Bulletin 2002年第1期47卷 82-85页

作者： ZHANG Donghe, XIAO Zuo & CHANG Qingdepartment of Geophysics, Peking University, Beijing 100871, china qingdao Research Center, china Research Insitute of Radio-wave Propagation, qingdao 266071, china department of Electronic engineering, Beijing Universit department of Geophysics Peking University Beijing China qingdao Research Center China Research Insitute of Radio-wave Propagation Qingdao China department of Electronic engineering Beijing University of Aeronautics and Astronautics Beijing China

The correlation of flare’s location on solar disc with the value of sudden increase of total electron content is analyzed with flare’s parameters observed by GOES satellite from 1997 to 1999 and total electron content derived from GPS data observed by international GPS Service for Geo-dynamics. It is found that, besides the flare’s maximum X-ray flux, flare’s location on solar disc has some relation with the value of SITEC during the flare. The ionospheric response to a flare with a smaller maximum X-ray flux and nearer angular distance to the Sun’s central meridian line may be stronger than that of the flare with a larger maxi-mum X-ray flux and far angular distance. To the flares with the same class of maximum X-ray flux, the nearer the angu-lar distance to the Sun’s meridian, the stronger the ionospheric response.

关键词： flare SITEC GPS.

A video encryption method based on chaotic maps in DCT domain

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Progress in Natural Science:Materials International 2008年第10期18卷 1299-1304页

作者： Shuguo Yang~(a,b,*) Shenghe Sun~a ~a School of electrical engineering and Automation,Harbin Institute of Technology,Harbin 150001,china ~b {3. University of Science and Technology,{3. 266061,china School of electrical engineering and Automation Harbin Institute of Technology Harbin 150001 China qingdao University of Science and Technology Qingdao 266061 China

This paper proposes a new and secure video encryption method based on chaotic maps in DCT domain,which is quite in keeping with the common ideas and the frequent practices of video *** select the I-frames of the video sequence as encryption objects. First,we introduce two coupling chaotic maps to scramble the DCT coefficients of every original I-frame,and receive the scrambled ***,we encrypt the DCT coefficients of the scrambled 1-frame using another chaotic *** the whole process,we use three chaotic maps and five keys;the I-frame is encrypted ***,we performed several tests and the experimental results have proved our method to be secure and efficient.

关键词： Video encryption Chaotic map I-frame Scrambling Video sequence

Lattice dynamical simulation of methane hydrate

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Journal of Natural Gas Chemistry 2010年第1期19卷 43-46页

作者： Lin Wang, Shunle Dong Physics department, College of Information Science and engineering, Ocean University of china, {3. 266100, Shandong, china Physics department College of Information Science and Engineering Ocean University of China Qingdao 266100 Shandong China

INS （Inelastic Neutron Scattering） spectrum of methane hydrate was measured on MARI （a direct-geometry chopper spectrometer） at Ruther-ford Appleton Laboratory, UK. Compared with ice Ih, it is found that the whole spectrum of methane hydrate moves toward high-energy by about 1.5 meV. Using lattice dynamical （LD） technique, computer simulations of methane hydrate were carried out. In the simulations, four potential models （BE TIP3., TIP4P, MCY） were employed to calculate the phonon density of states （PDOS）. Comparing the calculated PDOS spectrum with the experimental spectrum, it is found that BF, TIP4P, and TIP3. potential lattices give out well-separated translational and librational bands while MCY potential lattice is unstable to do so and this model is not suitable to describe hydrate system.

关键词： methane hydrate inelastic neutron scattering lattice dynamical simulation