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EFFECT OF THE OPEN CRACK ON THE PULL-IN INSTABILITY OF AN ELECTROSTATICALLY ACTUATED MICRO-BEAM

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Acta Mechanica Solida Sinica 2012年第6期25卷 627-637页

作者： Asadollah Motallebi Mohammad Fathalilou Ghader Rezazadeh Mech. eng. dept. Islamic Azad University Mech. eng. dept. Urmia University

In this paper, the effects of the open crack on the static and dynamic pull-in volt- ages of an electrostatically actuated fixed-fixed and cantilever micro-beam are investigated. By presenting a mathematical modeling, the governing static and dynamic equations are solved by SSLM and Galerkin-based Reduced Order Model, respectively. Then, each single-side open crack in the micro-beam is modeled by a massless rotational spring and the cracked mode shapes and corresponding natural frequencies are calculated by considering the boundary and patching con- ditions and using transfer matrix methods. Finally, the effects of the crack dept. ratio, crack position and crack number on the pull-in voltage of the micro-beams are studied. It is shown that beside the residual stresses created in the machining process, the crack（s） can be initiated, growth and consequently change the pull-in voltage of the system by decreasing the natural frequencies. The results show that the crack position is effective beside the crack dept. ratio in decreasing the pull-in voltage. Also it is shown that in the fixed-fixed micro-beam there are several points for the crack location in which, the pull-in voltage is extremum.

关键词： MEMS open crack electrostatic pull-in instability

Computational Fluid Dynamic Simulation of Liquid-Liquid Mixing in a Static Double-T-shaped Micromixer

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过程工程学报 2008年第6期8卷 1080-1084页

作者： Elmabruk A. MANSUR 王运东戴猷元 The State Key Lab. Chem. eng. Dept. Chem. Eng.Tsinghua University

The laminar flow structure and mixing performance of T-shaped and double-T-shaped micromixers with rectangular cross-section have been investigated using computational fluid dynamic (CFD) simulation. FLUENT software is used to evaluate the mixing efficiency. The numerical simulation results show that the presented double-T-micromixer is highly efficient over T-shaped micromixer. The performance of double-T-micromixer with and without static mixing elements (SME) is also investigated. The enhancement in mixing performance is thought to be caused by the generation of eddies and lateral velocity component when the mixture flows through these elements. Mixing efficiency as higher as 97% is reached within a mixing leng.h of 320 μm downstream from the first T-junction with the enhancement of three SMEs.

关键词：计算方法流体动力学模拟方法液液混合双T形微混合器物理过程

Numerical Simulation and Physical Simulation of Sea Wave Groups

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China Ocean eng.neering 1996年第3期11卷 295-305页

作者： Yu Yuxiu and Gui ManhaiProfessor, dept. of Civil eng. Dalian University of Technology (DUT), Dalian 116024 . Master, dept. of Civil eng. DUT, Dalian, 116024 dept. of Civil eng. Dalian University of Technology Dalian 116024 dept. of Civil eng. DUT Dalian 116024

Based on field wave data, an empirical formula of wave envelope spectrum is given in this paper. Then the methods of both numerical and physical simulation of sea wave groups with the given spectrum and groupiness par... 详细信息

关键词： wave group wave envelope spectrum numerical simulation physical simulation

Manganese vanadium oxide composite as a cathode for high-performance aqueous zinc-ion batteries

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Chinese Chemical Letters 2024年第9期35卷 491-495页

作者： Jiayu Bai Songjie Hu Lirong Feng.Xinhui Jin Dong Wang Kai Zhang Xiaohui Guo Key Lab of Synthetic and Natural Functional Molecule chemistry of Ministry of Education Shaanxi Key Laboratory for Carbon Neutral TechnologyThe College of Chemistry and Materials ScienceNorthwest UniversityXi’an 710069China Sustainable Materials and chemistry Dept.Wood Technology and Wood-based CompositesUniversity of GoettingenWilhelmsplatz 1(Aula)37073 GötingenGermany

The development of clean renewable energy and energy storage devices is of great significance under the present energy crisis and environmental pollution *** zinc-ion battery(ZIB)has become one of the most promising energy storage devices due to its high capacity,safety and low ***,the application of ZIB cathode is usually limited by low capacity and poor ***,we propose a novel heterostructure MnO/MnV_(2)O_(4)composite material composed of MOF derivatives and spinel with dual active components as cathode for *** from substantial framework of MOF derivatives and the synergistic effect of heterostructures,MnO/MnV_(2)O_(4)exhibits excellent rate performance(342 m Ah/g at 0.1 A/g,261 mAh/g at 15 A/g)and cycling performance(198.9 mAh/g at 10 A/g after 2000 cycles)in3 mol/L Zn(CF_(3)SO_(3))*** work extends the range of developing high-performance cathodes for ZIBs under high current density and is expected to enlighten the optimization of commercial energy storage devices.

关键词： Metal organic framework Manganese oxides Heterostructure Cathode Zinc ion battery

Fluvial Processes in the Meandering Reach of the Lower Wei River During the Course of Degradation

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四川大学学报（工程科学版） 2005年第S1期37卷 46-51页

作者： Xia, Junqiang Wang, Guangqian Wu, Baosheng dept. of Hydraulic eng. Tsinghua Univ. Beijing 100084 China

This paper presents an analysis of the changes of the longitudinal and lateral profiles in the meander- ing reach of the Lower Wei River over the period from October 1973 to October 1976 during the course of *** results indicated that retrogressive erosion and subsequent downstream erosion occurred in the reach due to the lowering in the Tongguan elevation and the inflowing water carrying low sediment con- *** the end of the degradation,the main channel widths of the majority ...

关键词： the Lower Wei River fluvial processes batse level of erosion channel widening channel undercut

Ce^(4+)-Induced Apoptosis of Taxus cuspidata Cells in Suspension Culture

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Journal of Rare Earths 2002年第2期20卷 139-144页

作者：葛志强元英进王艳东马振毅胡宗定 dept. of Biochem. eng. Sch. of Chem. Eng. and Technol. Tianjin Univ. Tianjin 300072 China

The standard detection hallmarks of apoptosis of Taxus cuspidata cells in suspension culture with Ce 4+ were studied. The condensation and margination of chromatin were observed under the electron microscopy. DNA fragmentation ranged 'DNA ladder' on agarose gel electrophoresis. TdT mediated dUTP nick end labeling (TUNEL) analysis of the cells reveals that the nuclear DNA strand breaks can be identified by labeling free 3′ OH termini. These results suggest that Ce 4+ can induce apoptosis of Taxus cuspidata cells and also indicate that there is a certain relationship between apoptosis and secondary metabolite product Taxol.

关键词： rare earths cerium apoptosis Taxus cuspidata cell suspension culture

DRYING OF GRANULAR MATERIALS IN AGITATED FLUIDIZED BED

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Journal of Hydrodynamics 2001年第2期13卷 29-31页

作者： Ma, J.H. Liu, H. Feng. D.Z. dept. of Air-Condition eng. Shandong Inst. of Civil Eng. Jinan 250014 China

An experimental study of the drying characteristics of an agitated fluidized bed dryer is presented and discussed. In the study, the citric acid particles were used as bed material with the diameters ranging from 0.2 mm to 1.3 mm. The variables affecting apparently the drying rate were found to be the mass flow rate, the inlet air temperature, the rotary speed of agitating mechanism and the particles feed rate. Comparing with other variables considered, mass flow rate was found to have the least important influence on the drying rate. The agitated fluidized bed dryer is suitable to drying agglomerating or sticky materials.

关键词： Dryers (equipment) Drying Experiments Mass transfer

Two Bandwidth Packing Algorithms for the Centralized Wireless Network and Their Average-case Analysis

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Journal of Shanghai Jiaotong university(Science) 2007年第3期12卷 397-404页

作者：陈建新龚玲杨宇航曾鹏 dept. of Electronic eng. Shanghai Jiaotong Univ. dept. of Computer eng. of Nanjing Univ. of Posts & Telecommunications

This paper presents a detail analysis of two bandwidth packing algorithms, used for processing connection requests in the centralized wireless network. Each call comes with a specific bandwidth request. A request can be satisfied only if there is sufficient bandwidth available during resource scheduling and allocation. Unsatisfied requests were held in a queue. The metric of bandwidth utilization ratio was used to quantify the performance of our algorithms. By theoretical analysis, our algorithms can improve the average bandwidth usage ratio significantly, about 8%~10% without adding much computation complexity. Moreover, our algorithms outperform next fit with fragmentation (NFF) algorithm when the bandwidth resource is scarce. In this paper, the contributions follows: Introducing bandwidth packing problem into wireless network; Proposing two new bandwidth packing algorithms for wireless network where the complicate scheduling algorithms are prohibited; Studying the average performance of our algorithms mathematically, which agree well with the simulation results.

关键词： wireless network average performance bandwidth packing problem (BWP)

A Direct Compensative Robust Optimal Control (DCROC) Law for Ship Straight-line Track-keeping

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Journal of Shanghai Jiaotong university(Science) 2007年第3期12卷 364-369页

作者：李文魁田蔚风周岗陈永冰周永余 dept. of Instrument Science & eng. Shanghai Jiaotong Univ. School of Electrical and Information eng. Navy Eng. Univ.

A linear quadratic optimal direct track-keeping control law was proposed based on first-order Nomoto nominal model. Furthermore, based on Lyapunov stabilized theory, considering parametric uncertainty from variations of ship speed and disturbances uncertain from wind, wave and sea current, a direct compensative robust optimal control (DCROC) law was developed. It can guarantee closed-loop system globally and uniformly converge to a remained set. High accuracy and robustness were achieved. By introducing some nonlinear blocks, closed-loop system achieves global and uniform asymptotical stableness. Numerical simulations on a Mariner Class ship are presented to validate the control law.

关键词： ship track-keeping direct compensative robust optimal control (DCROC) Lyapunov stability