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Unsteady Correlation between Pressure and Temperature Field on Impinging Plate for Dual Underexpanded Jets

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Journal of Thermal Science 2009年第3期18卷 215-219页

作者： Minoru YAGA Hiroyuki HIGA Shoichi MATSUDA Izuru SENAHA depts. Mech. systems eng. Univ. of the Ryukyus Graduate student Faculty of Eng. Univ. of the Ryukyus Okinawa National College of Technology

In this paper, dual underexpanded impinging jets are experimentally studied by measuring unsteady wall staticpressure and temperature fields using high response semiconductor pressure sensors and infrared imaging cam-era(100 captures per sec) with dual converging sonic nozzles. The flow field is also visualized by means of highspeed schlieren system( up to 70000 frame per second) to clarify the unsteady behavior of the jet structures suchas barrel shock wave, and Mach disk. Experiments were performed with a blow down tunnel changing the parameterssuch as the nozzle to plate distance, the distance between the two nozzles, and wind tunnel pressure *** nozzle to plate distance L and the distance between the two nozzles H are non-dimensionalized by the nozzlediameter D covering H/D=1.5, 2.0, and 3, L/D= 2, 3,and 4, and po/pb=1.0 - 5.0, where po and pb are stagnationpressure and back pressure respectively. Although the response of the infrared camera is quite different fromthat of the high speed camera, the unsteady correlation between the pressure and temperature fields is confirmedunder some conditions. Also the high speed schlieren pictures and the wall static pressure fluctuations suggestthat the generation of the Mach disk promote the unsteady behavior of the jets. After the confirmation of the correlation,a simple way to find the severe fluctuating region can be provided according to the two dimensional unsteadytemperature images without a lot of unsteady pressure measurements.

关键词： Shock wave CFD supersonic flow unsteady jet fluctuation

The Structural eng.neering Challeng.s Following the Wenchuan Earthquake

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四川大学学报（工程科学版） 2009年第3期41卷 223-230页

作者： GRUNDY Paul dept.of Civil eng. Monash Univ.

The "5·12" Wenchuan Earthquake presents two challeng.s-reconstruction of the devastated areas and building adequate seismic resistance into the rest of *** stages in recovery include structural condition assessment,identification of seismic weaknesses,appreciation of the variable seismicity of PR China,the development of a seismic performance index to aid the decision to relocate,rebuild or retrofit,development and application of the principles of retrofitting which recycles rubble and waste from Wenchuan "5·12",with an emphasis on integrating masonry construction into seismic *** recovery and resilience achieved through structural eng.neering must be integrated into a broader community involvement in disaster risk reduction.

关键词：建筑工程抗振结构建筑结构建筑物

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

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 depth 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 depth 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

Ultrasonic Approach of Rayleigh Pitch-Catch Contact Ultrasound Waves on CFRP Laminated Composites

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Journal of Materials Science & Technology 2008年第3期24卷 407-409页

作者： In-Young Yang Kwang-Hee Im Uk Heo David K Hsu Je-Woong Park Hak-Joon Kim Sung-Jin Song School of Mechanical eng. Chosun Univ Department of Automotive eng. Woosuk Univers-ity Center for Nondestructive Evaluation Iowa State University dept.of Naval Arch.and Ocean eng. Chosun Univ School of Mechanical eng. Sungkyunkwan University

CFRP （carbon fiber reinforced plastics） composite materials have wide applicability because of their inherent design flexibility and improved material properties. However, impacted composite structures have 50%-75% less streng.h than undamaged structures. In this work, a CFRP composite material was nondestructively characterized in order to ensure product quality and structural integrity of CFRP and one-sided pitch-catch technique was developed to measure impacted-damaged area by using an automated-data acquisition system in an immersion tank. A pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave under defect conditions in the composite.

关键词： Impact damages C-scanner Carbon fiber reinforced plastics (CFRP) Pitchcatch mode

Synchronal Measurement of Flow Structure and Heat Transfer of Impingement Jet

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Journal of Thermal Science 2010年第3期19卷 228-233页

作者： Shoichi MATSUDA Naomichi SAJI Minoru YAGA Masaaki ISHIKAWA Kenyu OYAKAWA dept.Mech.systems eng. Univ.of the RyukyusSenbaru 1NishiharaOkinawaJapan903-0213 Graduate student Faculty of Eng.Univ.of the RyukyusSenbaru 1NishiharaOkinawaJapan903-0213

This paper will present the characteristics of flow behavior and thermal field of both free and impingement jet issued from a circular orifice nozzle at Re=*** flow behavior of a single round jet and impingement jet was observed by smoke flow visualization recorded by a high speed camera using 5000 frame per *** transfer coefficient on the impingement surface was measured by means of infrared camera (TVS-8500,Avio) with a two-dimensional array of Indeum-Antimony (In Sb) sensors varying in the separation distance between the nozzle and the target *** heat transfer coefficient changes in time and ***,the root mean square distribution of the heat transfer was obtained from the *** a result,it was confirmed that the longitudinal vortex was observed outside of the ring vortex,and then the longitudinal vortex was penetrated in the jet ***,the high value of root mean square of the heat transfer coefficient has spread radially in stripy manner,which is caused as the results of the longitudinal vortexes flowing in the radial direction on the impingement plate.

关键词： Impingement jet Forced convection Heat transfer Ring vortex Longitudinal vortex

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

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

Partition Behavior of Penicillin in Three-liquid-phase Extraction System

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过程工程学报 2006年第3期6卷 363-368页

作者：谭显东季清荣常志东 dept. Environ. eng. Chengdu Univ. Information Technol.ChengduSichuan 610225China State Key Lab. Biochem. eng. Lab. Sep. Sci. & Eng.Inst. Process Eng.CASBeijing 100080China

Partition behavior of penicillins G and V was studied in a novel three-liquid-phase extraction system,which is composed of butyl acetate (BA),polyethylene glycol (PEG),ammonia sulfate (NH4)2SO4 and water (H2O). The main components in the top,middle and bottom phases are butyl acetate,polyethylene glycol aqueous solution and ammonia sulfate aqueous solution,respectively. Some parameters such as partition coefficients Di/j and mass fractions Ei of penicillins G and V were determined at the room temperature,respectively. Experimental efforts have been made to investigate the partition behavior of penicillin in the three-liquid-phase extraction system,including initial concentrations of phase-forming components PEG and (NH4)2SO4,PEG molecular weight,pH,initial concentration of penicillin. The results indicated that penicillins G and V have the similar partition behavior. They preferentially distribute into the middle phase with the increase of initial concentration of phase-forming components and into the top phase with the decrease of pH,while partition coefficient Dm/b is hardly affected by pH value. The variation of PEG molecular weight has little effect on mass fractions of penicillin. The increase of initial concentration of penicillins G and V could lead to the increase of Dt/b,Dm/b and the decrease of Dt/m,while their mass fractions in all phases were almost independent on their initial concentrations.

关键词： three-phase extraction penicillin partition