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Research on the Fault Monitoring System in Free-form Surface CNC Machining Based on Wavelet Analysis

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厦门大学学报（自然科学版） 2002年第S1期41卷 72-73页

作者： XU Shu-xin 1, ZHAO Ji 2, ZHAN Jian-ming 1, LE Guan 1 (1. college of Mechanical Science and engineering, jilin university, changchun 130022, china 2. Office of Education Administration, jilin university, changchun 130012, Chi na)

Carrying out experiments and researches on tool bre ak age and undercut of work-piece of free-form surface by using wavelet analysis, both the fault features can be extracted in a special frequency segment of wave let decompose. According to the feature of transient fault, the author proposes for the first time the automatic determination technology of the threshold by us e of the adaptive filter characteristic of wavelet transform. Based on profound researches on steady fault feature, this dissertation makes an effective token o f steady fault feature by using wavelet energy method, and proposes the new idea to identify cut-in case and cut-out case, thereby successfully gives an uniqu e description quantitatively on the characterization of the variation of fault a nd cutting condition in the monitoring system.

关键词： wavelet analysis free-form surfaces CNC mach ining monitoring system

ANALYTICAL AND NUMERICAL SOLUTIONS FOR THE FLOW IN MICROTUBE WITH THREE-DIMENSIONAL CORRUGATED SURFACE,PART 1:STEADY FLOW

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Journal of Hydrodynamics 2010年第5期22卷 647-656页

作者： WANG Hao-li YANG Meng WANG Yuan college of Metrological Technology and engineering China Jiliang University Hangzhou 310018China Department of Fluid engineering School of Energy and Power Engineering Xi＇an Jiaotong University Xi＇an710049 China

The influences of three-dimensional corrugated wall on the fully-developed steady no-slip flows in microtube are studied by analytical and numerical methods in this article. Detailed analytical solutions for the space-averaged equations and the numerical method for the solutions of the disturbance equations are given. An iterative arithm of coupled equations with respect to space-averaged velocities and disturbance velocities is suggested. The study shows that a three-dimensional subsidiary stress layer exists in the near-wall region. The relative roughness, wavenumber and Reynolds number are three important parameters influencing the subsidiary stresses and the space-averaged pressure drop. The space-averaged pressure drop subject to an invariable flow rate mainly depends on the position of datum surface. When the datum surface is taken at the balance position of wall function, the value of pressure drop is determined by the dynamic characteristics of the flow.

关键词： microtube three-dimensional corrugated surface space-averaged method subsidiary stress

A theoretical analysis of optical-to-THz conversion efficiency via optical rectification

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Science china(Technological Sciences) 2008年第12期51卷 2080-2088页

作者： LI DeHua1,QI XiaoDong2 & LIU ShengGang3 1 Terahertz Institute of Shandong university of Science & Technology,Qingdao 266510,china 2 changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,changchun 130033,china 3 Terahertz research center,Physical Electronics college,university of Electronics Science,Chengdu 610054,china Terahertz Institute of Shandong university of Science & Technology Qingdao 266510 China changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China Terahertz research center Physical Electronics College University of Electronics Science Chengdu 610054 China

A theoretical analysis of an ultra-short pulse converted to Terahertz radiation via optical rectification in nonlinear optical crystal is presented here;several factors that affect optical-to-THz conversion efficiencies are discussed;pulse durations affect the conversion efficiency effectively:when crystal length is equal to the optimal crystal length lc,optical-to-THz conversion efficiency is the highest,but for the periodically-inverted electro-optic crystals,conversion efficiency is almost proportional to the crystal length when absorption can be *** account of the absorption of crystals,effective length of crystal is Leff=0.63/α,there is no apparent increase of conversion efficiency and the conversion efficiency approaches to a constant eventually when the crystal length is increased.

关键词： optical rectification periodically inverted effective length conversion efficiency

New method for passive radar seeker to antagonize non-coherent radar decoy

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Journal of Systems engineering and Electronics 2010年第3期21卷 397-403页

作者： Weijian Si,Xicai Si,and Zhiyu Qu college of Information and Communication engineering,Harbin engineering university,Harbin 150001,P.R.china college of Information and Communication engineering Harbin Engineering UniversityHarbin 150001P.R.China

Using super resolution direction of arrival（DOA） estimation algorithm to reduce the resolution angle is an effective method for passive radar seeker（PRS） to antagonize non-coherent radar *** the power and correlation property between radar and non-coherent decoy,an improved subspace DOA estimation method based on traditional subspace algorithm is *** this new method uses the invariance property of noise subspace,compared with traditional MUSIC algorithm,it shows not only better resolution in condition of closely spaced sources,but also superior performance in case of different power or partially correlated *** this new method,PRS can distinguish radar and non-coherent decoy with good *** the simulation result and the experimental data confirm the performance of the method.

关键词： radar countermeasures passive radar seeker(PRS) non-coherent decoy direction of arrival(DOA) estimation.

Resonant Interaction between Atom and Large Period Quantized StandingLight Wave in a Quantized Trap

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Chinese Journal of Lasers 1997年第1期B6卷 39-42页

作者： WANG Xiaoguang Xie Chengjun LIU Xiuhuan LIU Xiaohua(Department of Computer, changchun university, changchun,130022 changchun Institute of Physics, Chinese Academy of Scieces, changchun, 130021 Department of Physics,jilin Teacher's college, jilin, 132011 Chungchun Univ Changchun China

A two-level atom in a quantized trap interacting with a large period quantized standing light wave is considered, an exactly solvable model is obtained. The coupling coeffiecients between the atom and the field are ti... 详细信息

关键词： quantized trap coherent state collapse and revival phenomenon

Taurine Inhibits Myocardial Fibrosis via PKC-ERK1/2 Signaling Pathways

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Chemical Research in Chinese Universities 2012年第1期28卷 84-90页

作者： WANG Li-ying1,2, LI Hong1 and YANG Shi-jie1 1. Department of Pharmacology, Norman Bethune college of Medicine, jilin university, changchun 130021, P. R. china 2. Department of Physiology, Basic Medicine college, Beihua university, jilin 132013, P. R. china jilin Univ Norman Bethune Coll Med Dept Pharmacol Changchun 130021 Peoples R China Beihua Univ Basic Med Coll Dept Physiol Jilin 132013 Jilin Peoples R China

Previous studies have demonstrated the important role of taurine in inhibiting proliferation of myofibrob lasts（myoFb） and myocardial fibrosis. However, the underlying mechanisms are unclear. The present study was de signed to shed light on this issue through exploring the signal pathways via in vitro experiments. Angiotension II （AngII） treatment significantly increased myoFb proliferation and the levels of collagens I and III（P〈0.05）, whereas taurine, PKCα（PKC： protein kinase C） specific inhibitor L-threo-dihydro-sphingosine（D4681）, ERK1/2 inhibitor （PD98095） abrogated myoFb proliferation and collagen levels（P〈0.05, P〈0.01, respectively）, and increased the G0/G1 phase rate and decreased S phase rate. Immunocytochemistry, confocal fluorescence staining and image analy sis showed that taurine could inhibit the translocation and expression of p-PKCαin membrane, and then inhibit nuc lear translocation and expression of p-ERK1/2. These results have statistically significant differences compared with those of AngII group（P〈0.01）. Western blot results also show that taurine could inhibit the protein expression of p-PKCα and p-ERK1/2. We used p-PKCα specific inhibitor D4681 in order to elucidate the relationship between p-PKCα and p-ERK1/2 in signal transduction pathways. Finally, the results show that the protein expression of p-ERK1/2 and nuclear translocation were suppressed in D4681 group.

关键词： Taurine Myocardial fibrosis Proliferation Signal transduction Cardiac remodeling

Dose-dependent Cytotoxicity and Oxidative Stress Induced by "Naked" Fe_3O_4 Nanoparticles in Human Hepatocyte

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Chemical Research in Chinese Universities 2012年第1期28卷 114-118页

作者： LIN Xin-li1, ZHAO Shu-hua1, ZHANG Long1, HU Gui-qin1, SUN Zhi-wei1,3 and YANG Wen-sheng2 1. School of Public Health, jilin university, changchun 130021, P. R. china 2. college of Chemistry, jilin university, changchun 130012, P. R. china 3. School of Public Health and Family Medicine, Capital Medical university, Beijing 100069, P. R. china jilin Univ Sch Publ Hlth Changchun 130021 Peoples R China jilin Univ Coll Chem Changchun 130012 Peoples R China Capital Med Univ Sch Publ Hlth & Family Med Beijing 100069 Peoples R China

The dose-dependent cytotoxicity effect on human hepatocyte（HL-7702 cells） induced by ＂naked＂ Fe3O4 nanoparticles was assessed through cell viabilities and lactate dehydrogenase（LDH） activities. Three important oxi dative indexes of the cells by glutathione peroxidase（GSH-Px）, superoxide dismutase（SOD） and malondialde hyde（MDA） were determined. The good correlation of the cell viabilities with their GSH-Px, SOD and MDA levels indicated that the cytotoxicity is related to activation of oxidative stress induced by Fe3O4 nanoparticles. The oxida tive stress also leads to corresponding DNA damage in a similar dose-dependent manner, followed by the changes of cell cycle and cell apoptosis. Such work provides important experimental data for the safety evaluation of superpa ramagnetic Fe3O4 nanoparticles.

关键词： Superparamagnetic Fe304 Cytotoxicity Oxidative stress DNA damage Cell cycle Cell apoptosis

OPTIMAL CONTROL APPLIED IN AUTOMATIC CLUTCH ENGAGEMENTS OF VEHICLES

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Chinese Journal of Mechanical engineering 2004年第2期17卷 280-283页

作者： Sun Chengshun Zhang Jianwu School of Mechanical and power engineering,Shanghai Jiaotong university,Shanghai 200030, china School of Mechanical and power engineering Shanghai Jiaotong University Shanghai 200030 China Department of Science and Technology Studies University College London WC1E 6BT UK

Start-up working condition is the key to the research of optimal engagementof automatic clutch for AMT. In order to guarantee an ideal dynamic performance of the clutchengagement, an optimal controller is designed by considering throttle angle, engine speed, gearratio, vehicle acceleration and road condition. The minimum value principle is also introduced toachieve an optimal dynamic performance of the nonlinear system compromised in friction plate wearand vehicle drive quality. The optimal trajectory of the clutch engagement can be described in theform of explicit and analytical expressions and characterized by the deterministic and accuratecontrol strategy in stead of indeterministic and soft control techniques which need thousands ofexperiments. For validation of the controller, test work is carried out for the automated clutchengagements in a commercial car with an traditional mechanical transmission, a hydraulic actuator, agroup of sensors and a portable computer system. It is shown through experiments that dynamicbehaviors of the clutch engagement operated by the optimal control are more effective and efficientthan those by fuzzy control.

关键词： Automatic clutch Optimal control Nonlinear system dynamics

CFD simulation of pressure fluctuation characteristics in the gas-solid fluidized bed:Comparisons with experiments

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Petroleum Science 2011年第2期8卷 211-218页

作者： Wang Qingcheng Zhang Kai Gu Hongyan Beijing Shenwu Thermal Energy Technology Co. LTD Beijing 102200 China State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China National engineering Lab for Biomass power Generation Equipment North China Electric Power University Beijing 102206 China Electrical engineering college Guizhou University Guiyang 550025 China

A simple hydrodynamic model based on two-fluid theory, taking into account the effect of discrete particles on both the gas- and solid-phase momentum equations, was used to numerically investigate the pressure fluctuation characteristics in a gas-solid fluidized bed with the aid of CFX 4.4, a commercial CFD software package, by adding user-defined Fortran subroutines. Numerical simulations together with typical experimental measurements show that pressure fluctuations originate above the distributor when a gas pulse is injected into the fluidized bed. The pressure above the bubble gradually increases due to the presence of a rising bubble. When the bubble passes through the bed surface, the pressure near the bed surface gradually decreases to a lower value. Moreover, the pressure signals in the bubbling fluidized beds show obviously periodic characteristics. The major frequency of pressure fluctuations at the same vertical position is affected slightly by the operating gas velocity, and the amplitude of pressure fluctuations is related to both the operating gas velocity and the vertical height. In this study, the influence of the operating gas velocity on the pressure wave propagation velocity can be ignored, and only two peak frequencies in the power spectrum of the pressure fluctuations are observed which are associated with the bubble formation above the distributor and its eruption at the bed surface.

关键词： Gas-solid fluidized bed CFD simulation experimental measurements propagation ofpressure fluctuations pressure wave velocity pressure fluctuation frequency