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Computing the Intersection of a Plane and Geometric Primitives in VRML Model for Rapid Prototyping Software

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武汉理工大学学报 2006年第S3期28卷 918-923页

作者： LI Zhanli SUN xiuying Department of Computer science & technology,xi’an university of science and technology,xi’an 710054,China, Department of Computer science & technology Xi'an University of Science and TechnologyXi'an 710054China

VRML(Virtual Reality Modeling Language)format as an international standard for virtual reality,has al- ready been widely adopted for graphical representation of 3D objects over the *** VRML model in RP(Rapid Prototyp- ing)can reduce the precision loss which is caused by triangulation in generating STL *** exploring a slicing method and de- veloping a slicing software for VRML model is important and significant to improve the accuracy of RP *** inter- sections of a plane and VRML model is the key operation in slicing *** paper presents a method for calculating the in- tersections between a set of parallel planes and VRML geometric *** on the analysis of the relative position between a plane and a geometric primitive,intersection conditions in all cases were obtained,and the geometric parameters and corresponding equations of intersections were *** algorithm had been tested,and applications show that it is robust and effective.

关键词： slicing VRML rapid prototyping intersection cylinder cone

Dynamic Analysis of PWM Switching DC-DC Converters

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Dynamic Analysis of PWM Switching DC-DC Converters

CES/IEEE 5th International Power Electronics and Motion Control Conference

作者： Liu Jian Wang Yuanbin xi’an university of science & technology/ School of Electrical & Control Engineering xi’an China School. of Electrical & Control Engineering Xi''an University of Science and Technology Xi'an China

ISBN: (纸本)1424404487;9781424404483

＜正＞The dynamic behavior of DC-DC converters is analyzed on the basis of a state-space averaged model including the feed back loop. The low frequency ripple behavior of DC-DC converters is analyzed in s filed. A buck DC-DC converter is used as an example. The condition causing oscillation and impulse during starting period and in case of input perturbation is obtained. The output to input voltage transfer function in the feedback loop is deduced. The stability requirement is obtained based on Hurwitz Stability Criterion. The frequency and amplitude of the low frequency ripple voltage are determined by using zero-pole analysis method. The proposed approach is verified by simulation and experiment results.

关键词： switching converters Pulse Width Modulation (PWM) dynamic analysis stability low frequency ripple voltage

来源： cnki会议评论

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液压油载体净化的理论与实验研究

煤炭学报 1997年第1期22卷 94-97页

作者： Zhang xi(university of science and technology Beijing) 北京科技大学

通过对污染液压油表面特性的分析，认为污染油液具有很强的表面活性，依此提出了液压油载体净化理论，进行了液压油载体净化的实验室试验．试验结果证明，污染液压油净化后的主要理化指标达到了新油水平．

关键词：液压油载体净化污染液压油矿山机械

Removal of Cr (VI) from Aqueous Solution Using Ultrafine Coal Fly Ash

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Journal of Wuhan university of technology(Materials science) 2010年第2期25卷 323-327页

作者：刘转年 College of Geology and Environment Xi'an University of Science and Technology

Coal fly ashes WSRA and BQRA were ball milled for 5 h to produce their ultrafine coal fly ashes WSUA and BQUA, respectively. Batch kinetic, isotherm and pH effect on adsorption were studied to evaluate removal of Cr （VI） from aqueous solutions by ultrafine coal fly ashes comparing with raw coal fly ashes. The kinetics of adsorption indicates the process to be intraparticle diffusion controlled and follows the Lagergren first-order kinetics for all coal fly ashes. The first-order rate constants （k1） of Cr （VI） adsorption onto WSRA, WSUA, BQRA and BQUA are 1.981, 1.497, 2.119 and 1.500 （×10^-2） min^-1, respectively. The adsorption capacities of WSUA and BQUA are much better than those of WSRA and BQRA. Equilibrium adsorption data of all coal fly ashes well satisfy the Langmuir isotherm. The adsorbed amounts of Cr （VI） onto WSUA and BQUA decrease from pH 2 to pH 6 and then increase up to pH 12.

关键词： ultrafine coal fly ash Cr (VI) adsorption wastewater treatment

A centrality measure based on spectral optimization of modularity density

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science China(Information sciences) 2010年第9期53卷 1727-1737页

作者： FU LiDong1,2*,GAO Lin1 & MA xiaoKe1 1School of Computer science and Engineering,xidian university,xi'an 710071,China 2College of Computer,xi'an university of science and technology,xi'an 710054,China 1. School of Computer science and Engineering Xidian University Xi’an 710071 China2. College of Computer Xi’an University of Science and Technology Xi’an 710054 China

Centrality analysis has been shown to be a valuable method for the structural analysis of complex *** is used to identify key elements within networks and to rank network elements such that experiments can be tailored to interesting *** this paper,we show that the optimization process of modularity density can be written in terms of the eigenspectrum of kernel *** on the eigenvectors belonging to the largest eigenvalue of kernel matrix,we present a new centrality measure that characterizes the contribution of each node to its assigned community in a network,called modularity density *** measure is illustrated and compared with the standard centrality measures by using respectively an artificial example and a classic network data *** statistical distribution of modularity density centrality is investigated by considering large computer generated graphs and two large networks from the real *** results show the significance of the proposed approach.

关键词： centrality modularity density centrality kernel matrix eigenspectrum

RESEARCH OF THE DYNAMIC CHARACTERISTICS ON A NEW HYDRAULIC SYSTEM OF ELECTRO-HYDRAULIC HAMMER

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Chinese Journal of Mechanical Engineering 2001年第2期14卷 171-174页

作者： Li Yongtang Lei Bufang Department of Mechanical Engineering,Taiyuan Heavy Machinery Institute Shi Enxiu xi’an university of science and technology 太原重型机械学院机械工程系山西太原西安理工大学陕西

A new typed hydraulic system of electro hydraulic hammer is researched and developed By means of power bond graphs the modeling and simulation to the dynamic characteristics of the new hydraulic system are performed The experimental research which is emphasized on the blowing stroke is also performed It is proved from the result of simulation and experiment that this new hydraulic system possesses such advantages as simplification of structure,flexibleness of operation and reliability of working Especially it possesses better dynamic characteristics

关键词： Electro hydraulic hammer Hydraulic system Dynamic characteristics Simulation

Effect of non-point source pollution on water quality of the Weihe River

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International Journal of Sediment Research 2011年第1期26卷 50-61页

作者： LI Jiake~(1*),LI Huaien~2,SHEN Bing~3,and LI Yajiao~4 xi’an university of technology,Key Lab of Northwest Water Resource and Environment Ecology of MOE,xi’an,Shaanxi,710048,China xi’an university of technology,Key Lab of Northwest Water Resource and Environment Ecology of MOE,xi’an,Shaanxi,710048,China, xi’an university of technology,Key Lab of Northwest Water Resource and Environment Ecology of MOE,xi’an,Shaanxi,710048,China, School of Architecture and Civil Engineering,xi’an university of science and technology,xi’an,Shaanxi, 710054,China, [a] Associate Prof. Dr. xi'an university of technology Key Lab of Northwest Water Resource and Environment Ecology of MOE xi'an Shaanxi 710048 China [b] Prof. Dr. xi'an university of technology Key Lab of Northwest Water Resource and Environment Ecology of MOE xi'an Shaanxi 710048 China [c] Prof. Dr. xi'an university of technology Key Lab of Northwest Water Resource and Environment Ecology of MOE xi'an Shaanxi 710048 China [d] Dr. School of Architecture and Civil Engineering xi'an university of science and technology xi'an Shaanxi 710054 China

Non-point source pollution is an important factor that affects the water quality of the Weihe *** study the effect of the pollution on the water quality of the Weihe River,five flood events and three normal discharge events during non-flood period were monitored from July to December in 2006,at the Lin-tong *** order to identify how sediment influenced the water quality of the river,raw and supernatant samples taken from the monitored events were *** samples were siphoned from 5 cm below the water surface of the raw samples at the lab afterwards the raw samples were shaken up and laid for 30 minutes in the *** results indicated that:1) The concentrations of SS,COD,TP and TN in the raw samples from flood events were higher than those from normal discharge *** higher values of the COD,TP and TN in the raw samples resulted from natural humic matters in surface soil.2) The load transport rate of analyzed water quality indexes increased gradually to its maximum and then drop down,matching that in the discharge *** concentrations of SS,NH-N,NO-N,NO-N,COD,and TP in the raw samples increased initially and then decreased,while the concentration of dissolved orthophosphate and TN in the raw samples decreased gradually and then *** peak time of concentration and load transport rate of SS as well as COD,TP and TN in the raw samples were close to or lagged behind the time of peak flow. Generally,the peak time of concentration and load transport rate of dissolved orthophosphate, dissolved total-phosphate,NH-N,NO-N,and NO-N occurred prior to the time of peak flow.3) The mean concentration method was used to calculate the NPS pollution load at Lin-tong section,and the results are *** 2006,the proportions of the NPS pollution load to the total load for COD,TP, TN and inorganic nitrogen were more than 30%.

关键词： Weihe River Non-point source pollution Flood Monitoring Load

Effects of Nitrogen Doping on Microstructure and Photocatalytic Activity of Nanocrystalline TiO_2 Powders

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Journal of Wuhan university of technology(Materials science) 2007年第3期22卷 457-461页

作者：杨志远 Dept. of Chemistry and Chemical Engineering Xi’an University of Science and Technology

Nitrogen-doped TiO2 nanocrystalline powders were prepared by hydrolysis of tetrachloride titanium （TiCl4） in a mixed solution of ethanol and ammonium nitrate （NH4NO3） at ambient temperature and atmosphere followed by calcination at 400 ℃ for 2 h in air. FTIR spectra demonstrate that amine group in original gel is eliminated by calcination, and the TiO2 powder is liable to absorb water onto its surface and into its capillary pore. XRD and SEM results show that the average size of nanocrystalline TiO2 particles is no more than 60 nm and with increasing the calcination temperature, the size of particles increases. XPS studies indicate the nitrogen atom enters into the TiO2 lattice and occupies the position of oxygen atom. The nitrogen doping not only depresses the grain growth of TiO2 particles, but also reduces the phase transformation temperature of anatase to futile. The photocatalytic activity of the nitrogen-doped TiO2 powders has been evaluated by experiments of photocatalytic degradation aqueous methylene blue.

关键词： titanium oxide nitrogen doping photocatalytic activity nanocrystalline methylene blue

具有随机寿命的多维Black-Scholes定价模型

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系统工程理论与实践 2004年第8期24卷 44-48页

作者：薛红西安工程科技学院理学院陕西西安710048

　利用随机微分方程和鞅方法,给出了具有随机寿命的多维Black-Scholes定价模型,并获得随机寿命情形下欧式期权及其它未定权益定价的解析表达式.将Black-Scholes定价模型进行了更为合理地推广.

关键词：随机微分方程鞅方法 Black—Scholes定价模型未定权益