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three-Dimensional Lattice Kinetic Scheme and its Application to Simulate Incompressible Viscous thermal Flows

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Communications in Computational Physics 2007年第2期2卷 239-254页

作者： y.Peng C.Shu y.t.Chew Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260.

In this paper,the three-dimensional lattice kinetic scheme is presented to simulate incompressible viscous thermal *** compared with the standard LBM,the present scheme has the following good *** can save the computer memory since there is no need to store the density *** the conventional NS solvers,the implementation of boundary conditions is straightforward since the dependent variables are the macroscopic flow *** easy implementation of boundary conditions is a good property for solving three-dimensional flow *** present scheme is validated by simulating the three-dimensional natural convection in an air-filled cubical enclosure,which is heated differentially at two vertical side *** obtained numerical results compare very well with available data in the literature.

关键词： Lattice kinetic scheme lattice Boltzmann method three-dimensional incompressible flow natural convection thermal flow.

Viral infections and cell cycle G2/M regulation

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Cell Research 2005年第3期15卷 143-149页

作者： Richard y. ZHAO,Robert t. ELDER Children's Memorial Research Center Northwestern University Feinberg School of Medicine Chicago IL 60614 USA

Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast (Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15 (tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. these Cdc2 regulators are the downstream targets of two well- characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins, which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest. Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small t antigen, polyomavirus t antigen, HtLV tax and adenovirus E4orf4. thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

关键词： HIV-1 Vpr cell cycle G2/M regulation DNA damage DNA replication checkpoints viral infections fission yeast Schizosaccharomyces pombe.

PREDICtION OF CARBON CONCENtRAtION AND FERRItE VOLUME FRACtION OF HOt-ROLLED StEEL StRIP DURING LAMINAR COOLING

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 251-257页

作者： y.t. Zhang C.Z. Wang D.Z. Li y.y. Li School of Material Science and Engineering Shenyang Ligong University Shenyang 110168 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A phase transformation model was presented for predicting the phase fraction transformed and the carbon concentration in austenite for austenite to ferrite transformation during laminar cooling on run-out table in hot rolling strip mill. In this model, the parameter k in Avrami equation was developed for carbon steels. the wide range of chemical composition, the primary austenite grain size, and the retained strain were taken into account. It can be used to predict the ferrite volume fraction and the carbon concentration in austenite of hot-rolled steel strip during laminar cooling on run-out table. the coiling temperature controlling model was also presented to calculate the temperature of steel strip. the transformation kinetics of austenite to ferrite and the evolution of carbon concentration in austenite at different temperatures during cooling were investigated in the hot rolled Q235B strip for thickness of 9.35, 6.4, and 3.2mm. the ferrite volume fraction along the length of the strip was also calculated. the calculated ferrite volume fraction was compared with the log data from hot strip mill and the calculated results were in agreement with the experimental ones. the present study is a part of the prediction of the mechanical properties of hot-rolled steel strip, and it has already been used on-line and off-line in the hot strip mill.

关键词： carbon concentration ferrite volume fraction laminar cooling hot rolling

Purge and trap method to determine alpha factors of VOC liquid-phase mass transfer coefficients

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Chinese Science Bulletin 2000年第S1期45卷 76-79页

作者： S.C.lee L.y.Chan C.y.Chan Department of Civil & Structural Engineering The Hong Kong Polytechnic UniversityHong KongChina Correspondence should be addressed to Wang XinmingDepartment of Civil & Structural EngineeringThe Hong Kong Polytechnic UniversityHong KongChina Correspondence should be addressed to Wang XinmingDepartment of Civil & Structural EngineeringThe Hong Kong Polytechnic UniversityHong KongChina Correspondence should be addressed to Wang Xinming

A theoretical approach and laboratory practice of determining the alpha factors of volatile organic compound (VOC) liquid-phase mass transfer coefficients are present in this study. Using Purge & trap Concentrator, VOC spiked water samples are purged by high-purity nitrogen in the laboratory, the VOC liquid-phase mass transfer rate constants under the laboratory conditions are then obtained by observing the variation of VOCs purged out of the water with the purge time. the alpha factors of VOC liquid-phase mass transfer coefficients are calculated as the ratios of the liquid-phase mass transfer rate constants in real water samples to their counterparts in pure water under the same experimental conditions. this direct and fast approach is easy to control in the laboratory, and would benefit mutual comparison among researchers, so might be useful for the study of VOC mass transfer across the liquid-gas interface.

关键词： mass transfer coefficient purge and trap volatile organic compounds alpha factor.

Fault detection method with PCA and LDA and its application to induction motor

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Journal of Central South University 2010年第6期17卷 1238-1242页

作者： JUNG D y lee S M 王洪梅 KIM J H lee S H Daeho tech Company Limited Department of Electronics Engineering Inha University School of Mechatronics Changwon National University

A feature extraction and fusion algorithm was constructed by combining principal component analysis(PCA) and linear discriminant analysis(LDA) to detect a fault state of the induction *** yielding a feature vector with PCA and LDA from current signal that was measured by an experiment,the reference data were used to produce matching *** a diagnostic step,two matching values that were obtained by PCA and LDA,respectively,were combined by probability model,and a faulted signal was finally *** the proposed diagnosis algorithm brings only merits of PCA and LDA into relief,it shows excellent performance under the noisy *** simulation was executed under various noisy conditions in order to demonstrate the suitability of the proposed algorithm and showed more excellent performance than the case just using conventional PCA or LDA.

关键词： principal component analysis (PCA) linear discriminant analysis (LDA) induction motor fault diagnosis fusionalgorithm

the Effect of Reflector with Sound-Absorbing Material on Supersonic Jet Noise

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Journal of thermal Science 2005年第1期14卷 22-27页

作者： y.-H.KWEON M.tSUCHIDA y.MIyAZAtO t.AOKI H.-D.KIM t.SEtOGUCHI Department of Energy and Environmental Engineering Kyushu University Kasuga 816-8580Japan School of Mechanical Engineering Andong National University Andong 760-749Korea Department of Mechanical Engineering Saga University Saga 840-8502Japan

this paper describes an experimental work to investigate the effect of a reflector on supersonic jet noise radiated from a convergent-divergent nozzle with a design Mach number *** the present study,a metal reflector and reflectors made of three different sound-absorbing materials(grass wool and polyurethane foam)were employed,and the reflector size was *** measurement is carried out to obtain the acoustic characteristics such as frequency,amplitude of screech tone and overall sound pressure level(OASPL).A high-quality schlieren optical system is used to visualize the detailed structure of supersonic *** results obtained show that the acoustic characteristics of supersonic jet noise are strongly dependent upon the jet pressure ratio and the reflector *** is also found that the reflector with sound-absorbing material reduces the screech tone amplitude by about 5-13dB and the overall sound pressure levels by about 2-5dB,compared with those of the metal reflector.

关键词： supersonic jet supersonic jet noise screech tone OASPL reflector sound-absorbing material.

X-ray Peak-Shift Determination of Deformation Fault Probability in Fe-Mn-Si Alloys

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Journal of Materials Science & technology 2002年第5期18卷 459-461页

作者： yonghuaRONG GangHE ZhenghongGUO ShipuCHEN t.y.Hsu(XUZuyao) Sch. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

the X-ray diffraction peak-shift method was introduced into the determination of deformation fault probability (a) of Fe-Mn-Si alloys with various Mn contents and thermomechanical cycling numbers. the precise lattice constants required were obtained by numerical calculation instead of using standard sample without any fault. the influence of internal stress on the determined a has been evaluated, and the caused relative error was determined as about 4% and thus negligible. the results show that the deformation fault probability increases with decreasing Mn-content and increasing cycle number, which are qualitatively consistent with those results of Psf determined by peak-broadening method.

关键词： X-ray diffraction Peak-shift method Deformation fault probability Fe-Mn-Si alloy

Closed-form solutions for free vibration of rectangular FGM thin plates resting on elastic foundation

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Acta Mechanica Sinica 2016年第6期32卷 1088-1103页

作者： t. F. Xu y. F. Xing Institute of Solid Mechanics Beihang UniversityBeijing 100191 China China Academy of Launch Vehicle technology R&D Center Beijing 100076 China

this article presents closed-form solutions for the frequency analysis of rectangular functionally graded material (FGM) thin plates subjected to initially in-plane loads and with an elastic foundation. Based on classical thin plate theory, the governing differential equations are derived using Hamilton's principle. A neutral surface is used to eliminate stretching-bending coupling in FGM plates on the basis of the assumption of constant Poisson's ratio. the resulting governing equation of FGM thin plates has the same form as homogeneous thin plates. the separation-of-variables method is adopted to obtain solutions for the free vibration problems of rectangular FGM thin plates with separable boundary conditions, including, for example, clamped plates. the obtained normal modes and frequencies are in elegant closed forms, and present formulations and solutions are validated by comparing present results with those in the literature and finite element method results obtained by the authors. A parameter study reveals the effects of the power law index n and aspect ratio a/b on frequencies.

关键词： Functionally graded material Free vibration Rectangular plate Close form solutions Neutral surface

Dynamic stabilization of plasma instability

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High Power Laser Science and Engineering 2019年第1期7卷 17-26页

作者： S.Kawata t.Karino y.J.Gu Graduate School of Engineering Utsunomiya University Institute of Physics of the ASCR ELI-Beamlines Institute of Plasma Physics of the CAS

the paper presents a review of dynamic stabilization mechanisms for plasma instabilities. One of the dynamic stabilization mechanisms for plasma instability was proposed in the paper [Kawata, Phys. Plasmas 19, 024503(2012)],based on a perturbation phase control. In general, instabilities emerge from the perturbations. Normally the perturbation phase is unknown, and so the instability growth rate is discussed. However, if the perturbation phase is known, the instability growth can be controlled by a superimposition of perturbations imposed actively. Based on this mechanism we present the application results of the dynamic stabilization mechanism to the Rayleigh–taylor instability(RtI) and to the filamentation instability as typical examples in this paper. On the other hand, in the paper [Boris, Comments Plasma Phys. Control. Fusion 3, 1(1977)] another mechanism was proposed to stabilize RtI, and was realized by the pulse train or the laser intensity modulation in laser inertial fusion [Betti et al., Phys. Rev. Lett. 71, 3131(1993)]. In this latter mechanism, an oscillating strong force is applied to modify the basic equation, and consequently the new stabilization window is created. Originally the latter was proposed by Kapitza. We review the two stabilization mechanisms, and present the application results of the former dynamic stabilization mechanism.

关键词： dynamic instability stabilization filamentation instability plasma instability Rayleigh-taylor instability stabilization of instability