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Journal of Jiangsu University(Natural Science Eidtion)

	2010 Vol.31 Issue.3 Published 2010-05-10

	Article

Article

	249	*Identification of green teas by HPLC and pattern recognition*
		Zhao Jiewen, Guo Zhiming- , Chen Quansheng
		Identification of green teas was made according to catechins and caffeine contents.Five varieties of green teas were tested in the experiment.First,the contents of catechins（epigallocatechin,epicatechincatechin,epigallocatechin gallate,epicatechin gallate） and caffeine were determined by HPLC.Then,Linear Discriminant Analysis（LDA）,K-Nearest Neighbors（KNN）,and Back-Propagation Artificial Neural Networks（BP-ANN） were applied comparatively to identify tea varieties as pattern recognition method.Experimental results showed that the best identification model was achieved by BP-ANN,and the identification rates for calibration set and prediction set samples were 98%and 92%,respectively.It is feasible to identify green tea varieties according to the analysis of catechins and caffeine contents by HPLC coupled with ANN pattern recognition.
		2010 Vol. 31 (3): 249-253 [Abstract] ( 1735 ) [HTML 1KB] [ PDF 310KB] ( 1714 )

	254	*Hydrodynamic lubrication performance on multi-textured surface structured by multi-arcs and triangle textures*
		Ruan Hongyan, Lv Jianjun , SiHui, Liu Huixia, Wang Xiao
		Appropriate surface texture can improve hydrodynamic lubrication performance for kinematic pairs.A geometrical model of multi-textured surface constructed by multi-arcs and triangles is established while a hydrodynamics control equation is preserved.Using CFD software FLUENT,the hydrodynamic lubrication performance of multi-textured surface is computed.It shows that the multi-textured surface performs better compared with the independent-textured surface.The former gives a more appropriate pressure distribution and thus produces a higher thrust force.
		2010 Vol. 31 (3): 254-258 [Abstract] ( 1370 ) [HTML 1KB] [ PDF 311KB] ( 1503 )

	259	*Adsorption isotherms and thermodynamic properties of camellia oleiferaseeds*
		Wu Xuehui, Li Changbao, Yang Gongming
		In order to reveal the complex relationships among the moisture content,the water activity and the temperature of camellia oleiferaseeds,and to provide fundamental data for storage and processing,the adsorption isotherms of camellia oleiferaseeds at different temperatures were determined by statically adjusting the ambient humidity based on the adsorption theory.The obtained isotherms were fitted to five commonly-used mathematical models.The thermodynamic properties of camellia oleiferaseeds were analyzed.The results indicate that the modified Henderson model is most suitable for fitting the isotherms（R2=0.999 9,RMSE=0.007 1）.The absolutely-safe and the relatively-safe storage moisture contents of camellia oleiferaseeds were calculated according to the fitted isotherm model,which reached to 9.48% and 8.00% at 20 ℃,8.96% and 7.57% at 30 ℃,8.51% and 7.19% at 40 ℃,respectively.The thermodynamic properties of camellia oleiferaseeds show that both the isosteric heat and the adsorbing energyof the seeds gradually decrease with the equilibrium moisture content,and the adsorbing energy increases with the temperature at a constant equilibrium moisture content.
		2010 Vol. 31 (3): 259-263 [Abstract] ( 1540 ) [HTML 1KB] [ PDF 317KB] ( 1941 )

	264	*A mathematical model for intelligent typesetting of label character strings*
		Yao Huixue, Lu Jinzhong, Feng Aixin, Lu Zhangping
		In order to meet the demand of automatic machining of label characters NC engraving,a mathematicalmodel for intelligent typesetting of label character strings in a circular area is constructed.The model is based on the nonlinear programming theory,and treats circular labels as typical templates.The inputs are engraving character strings,linage and geometric parameters of the circular area.The optimizationobjective is to get the maximum area engraved.The constraints are engraving operability and characters definition.It automatically calculates the parameters of start points,text height and line spacingof the strings,fulfills the intelligent typesetting in the circular area,and achieves the coordinate points on character strokes to prepare complete data for NC engraving.An automatic engraving system is devised to test the validation of the model.Experimental results show that the model can accomplish the intelligent typesetting to get a clear and perfect engraving effect.The model is extensible,and presents a new method for label character strings typesetting.
		2010 Vol. 31 (3): 264-268 [Abstract] ( 1429 ) [HTML 1KB] [ PDF 314KB] ( 1264 )

	269	*Simulation of methanol droplet evaporation in quiescent environment*
		Ni Peiyong, Wang Zhong, Mao Gongping, Yuan Yinnan
		For a single methanol droplet in quiescent environment,the evaporation characteristics were simulated using the non-equilibrium evaporation model.The effects of the ambient pressure,temperature,and the droplet radius and temperature at the initial droplet temperature condition were investigated.The results indicate that the droplet equilibrium temperature increases with the increase of ambient pressure.The droplet evaporates faster when the ambient temperature is lower than the critical temperature and it evaporates slower when the ambient temperature is higher than the critical temperature.With the ambient temperature rising,the droplet evaporates faster and the equilibrium temperature increases.The initial droplet temperature has certain influences on the droplet vaporization in transient heating process and has little effect on the droplet vaporization in equilibrium process.
		2010 Vol. 31 (3): 269-272 [Abstract] ( 1572 ) [HTML 1KB] [ PDF 256KB] ( 2012 )

	273	*Ratio control strategy of continuously variable transmission for ramp-driving working condition*
		Zhang Shupei, Zhang Youkun, Wang Qingnian, Zhang Lei
		To solve the problem that the existing control strategy of CVT vehicles can not guarantee the lowest fuel consumption when driving at slope-road,and based on the analysis of power performance and economical efficiency,the optimal matching line control strategy was proposed.Based on the bench test of engine,the whole vehicle model was established in Matlab/Simulink.A large number of simulation experimentswere carried out,and fuel consumptions at different transmission ratios under various slope-roadconditions were determined.The fuel consumptions were reasonably matched with power performances,and the optimal matched line was obtained.Thus the control target of transmission ratiowas obtained.The results of simulation for typical working conditions show that precise control of transmi-ssionratio can be obtained and the optimal match of fuel consumption with power performance is realized.
		2010 Vol. 31 (3): 273-277 [Abstract] ( 1505 ) [HTML 1KB] [ PDF 321KB] ( 1605 )

	278	*Modeling of variable steering ratio with steady-state gain for active steering system*
		Shang Gao gao, Hong Ze, Zhang Hongdang, Lou Shi, He Ren
		Based on the analysis of power transmission mechanism and the front steering angle synthesis mode in Active Front Steering（AFS） system,the kinematic models of steering wheel angle and superposition angle were established.Meanwhile the transmission efficiencies of the single and dual planetary gear sets were compared by calculating the difference between output shaft speed with the input one.Based on the principle of dual planetary gear set,the relation between motor steering angle and steering wheel anglewas described as well.Furthermore,in order to improve the dynamic steering response and the high speed driving stability of vehicle,the mathematic model of variable steering ratio was established by a reasonable assumption.The simulation results show the special functions of variable steering ratio.It means that the driving comfort and active safety can be both improved by AFS.
		2010 Vol. 31 (3): 278-282 [Abstract] ( 1932 ) [HTML 1KB] [ PDF 326KB] ( 2102 )

	283	*Improvement and validation of ADSL driving simulator dynamic model*
		Zhan Jun, Guan Xin, Yang Dejun, Wang Peng
		In order to improve the fidelity of the ADSL driving simulator,the new steering model,wheel model and braking model are proposed.The force-input steering model considers the system elasticity.The wheel model considers the elasticity of pneumatic tire,dynamics of contact patch and contact model.The break model uses stick-slip friction model.The new model can truly calculate the correspondence of left and right steering wheels and the tire force,and simulate the stand-still,braking and zero speed.By comparing the handling results of new model,2000 model and the field test,the correctness of the model is validated.It is concluded that the precision of the new model is high.
		2010 Vol. 31 (3): 283-287 [Abstract] ( 1456 ) [HTML 1KB] [ PDF 330KB] ( 1776 )

	288	*Microstructure and properties of bagasse-based woodceramics*
		Cheng Xiaonong, Pan Jianmei, Yan Xuehua, Zhang ChengHua
		The bagasse-based woodceramics were prepared with different proportion of the bassage and epoxy resin in vacuum tube at high temperature after hot-pressing.Themogravimetric and diffential scanningcalorimeter analysis（TG-DSC） were applied to reveal the pyrolysis behavior of the bagasse-based woodceramics.Woodceramics were investigated by x-ray diffraction（XRD） and scanning electron microscopy（SEM）.The effects of the bagasse amount on the friction properties and the appareant porosity were studied.Experimental results show that the bagasse-based woodceramics have biological tubular porous structure.With the decrease of the bagasse amount,the graphitization degree of woodceramics increases.The appareant porosity of woodceramics becomes smaller with the decrease of the bagasse amount.The friction coefficient of the woodceramics increases with the increase of the rotation speed,but the friction coefficient decreases with the increase of the load.When the mass ratio of epoxy resin and bagasseis 1,the apparent porosity of woodceramics is 35.12% and the friction property is the best.
		2010 Vol. 31 (3): 288-291 [Abstract] ( 1541 ) [HTML 1KB] [ PDF 303KB] ( 1509 )

	292	*Experiment of stainless steel corrosion and scaling in geothermal water supply pipeline*
		Zhu Liqun, Chen Wei, Li Weiping, Liu Huicong
		The corrosion and scaling on the surface of the 304 stainless steel（SS） pipe in the flowing geothermalwater at 50 ℃ were studied using the circulating-water environment simulator.The effects of corrosion and scaling on mass concentration of ions in geothermal water,corrosion potential and mass of the SS pipe were discussed.The results show that the needlelike scales were accumulated on the surface of the sample.The pitting corrosion also occurs.With time increasing,the density of corrosion pits increases.Due to the corrosion,scaling and descaling on the surface,the concentrations of Ca2＋and Mg2＋decline significantly in the first 600 h,after that they keep constant.The corrosion potential of the SS pipe increases in the first 350 h,then it is stable at 0.044 V.The quality keeps increasing during the whole soaking process.
		2010 Vol. 31 (3): 292-295 [Abstract] ( 1783 ) [HTML 1KB] [ PDF 300KB] ( 1763 )

	296	*Numerical analysis of residual stresses in quenching of aluminum alloy thick plates*
		Xu Xiaojing, Wei Baocun, Fang Shiyi, Cheng Xiaonong
		Aluminum alloy thick plates have been widely used as the key material of aircraft structures.Quenching process is one of the most important methods for improving material performance,which introduces a high level of residual stresses and easily lead to distortion and quench cracks,resulting in the performance deterioration.In this paper,the effect of aluminum alloy dimensions and quenching medium temperatures on quenching residual stress was investigated using the finite element program ANSYS.A non-linear heat transfer analysis is carried out by taking into account of the temperature dependence of the thermo-physical properties and transient condition of convection.The results show that for thin aluminum alloy plate,with increasing plate thickness the quenching residual stress increases considerably,while for thick aluminum alloy plate,the quenching residual stress remains almost unchanged.It is believed that improving hardenability of aluminum alloy is the only effective approach for thick aluminum alloy to obtain combination of high mechanical properties and low quenching residual stress after quenc
		2010 Vol. 31 (3): 296-299 [Abstract] ( 1309 ) [HTML 1KB] [ PDF 286KB] ( 1524 )

	300	*Influence of silane content on micro-structure and optical property of nc-Si：H films*
		Ding Jianning, Gao Xiaoni, Yuan Ningyi, Cheng Guanggui, Guo Liqiang
		The intrinsic hydrogenated nano-crystalline silicon films of varied silane volume fraction have been deposited on the corning 7059 glass substrate by plasma enhanced chemical vapor deposition assisted with direct current bias.By Raman spectrometer,atomic force microscope and ultraviolet-visible transmission spectrometer the effects of the different silane volume fraction on the micro-structure and opticalproperty of films have been studied.The results show that when silane volume fraction increases,the crystalline size increases,whereas the crystal content decreases.The decrease of crystal content is the main cause for the decrease of the Raman peak intensity,the blue shift of peak position as well as the weakness of ordering character.The optical band-gap is in direct ratio to silane volume fraction.When silane volume fraction is equal to 1.3%,the films are deposited.Even nano-size crystals distribute regularlyand their deposition is in ordered orientation.The crystalline size and crystal content of these samples are nearly 2.6 nm and 50%.The film exhibits a large optical band-gap of 1.702 eV and a relatively high conductivity.
		2010 Vol. 31 (3): 300-303 [Abstract] ( 1204 ) [HTML 1KB] [ PDF 290KB] ( 1433 )

	304	*Combustion characteristics and dynamic modeling of micro engine*
		Chen Junjie, Wang Qian
		In order to obtain ignition and combustion characteristic parameters of the micro Homogeneous Charge Compress Ignite（HCCI） free-piston engine,numerical model of operation process of micro HCCI free-piston engine was developed.A method was proposed to simulate the operation of single-shot micro HCCI free-piston engine based on the kinetic characteristics of free-piston engine.A method of varying the influencing parameters was used to simulate the operation of single shot process of micro HCCI free-pistonengine coupled with the detailed chemical kinetic model of propane.The change of ignition time and combustion characteristics were obtained under the conditions of different initial conditions.The computational results indicate that initial temperature,initial pressure and equivalence ratio of fuel have important influence on ignition and combustion process of micro HCCI free-piston engine.
		2010 Vol. 31 (3): 304-308 [Abstract] ( 1296 ) [HTML 1KB] [ PDF 338KB] ( 1400 )

	309	*Experiment on solid-liquid suspension in unbaffled stirred tank*
		Lai Yongbin, Yang Minguan
		Solid-liquid suspension performance in a high solid concentration was investigated.An unbaffled,flat bottom,cylindrical glass vessel of diameter d=0.34 m equaling to the liquid height was used,which was stirred with two different axial flow impellers,a ZHX propeller and a 45° pitched blade turbine（PBT） impeller.The spherical glass particles of 150 μm were chosen as dispersed phase.The particle volume fraction was 20%.The states of suspension were observed and recorded using a digital camera.The just-suspended speed was determined by making visual observations through the base of the vessel illuminatedby a laser light source.The effects of impeller off-bottom clearance,type of axial impeller and eccentricity of the impeller in eccentric agitation operation on the solid suspension states,the just-suspended speed and power consumption were examined.The experimental results show that,either co-axial agitationor eccentric agitation,solid particles at the corners of the tank base can not suspend simultaneosly along circular direction.The suspension of solid particles in the stirred tank can be improved by decreasing impeller off-bottom clearance height.Solid particles reach the better suspension when using PBT than ZHX.The just-suspended speed and power consumption increase with increasing eccentricity in eccentric agitation operation.The eccentric agitation has no effective action to improve the suspension performance in a high solid concentration stirred tank.
		2010 Vol. 31 (3): 309-313 [Abstract] ( 1315 ) [HTML 1KB] [ PDF 385KB] ( 1460 )

	314	*Harmonic current detecting method based on modified VSS LMS algorithm*
		Liu Guohai, Liu Ying, Chen Zhaoling, Yang Chenxing, Zhang Yi
		In order to suppress and compensate the harmonic current effectively to improve the power quality,based on the analysis of universal expression given for the available harmonic current detecting methods,an improved harmonic current detecting method using VSS LMS algorithm was proposed.The parameters of iteration steps were determined to ensure that the selection of parameters had no adverse effect on the algorithm convergence.A variable step-size LMS/LMF algorithm was applied to update the weights,and the step-size was adjusted by means of the normalized autocorrelation estimation of two error signals.The simulation model was established by using Matlab.The method was realized on a TMS320F2812 chip.The results of simulation and experiments show the feasibility and effectiveness of the proposed method
		2010 Vol. 31 (3): 314-317 [Abstract] ( 1720 ) [HTML 1KB] [ PDF 311KB] ( 1691 )

	318	*An improved sub-SAT algorithm of adding symmetry-breaking*
		Tang Yulan, Zhang Huiguo, Yu Zongguang
		In order to eliminate the negative effect of increasing running time of sub-SAT algorithm in the routing process,a new routing flow was proposed.Additional variables and clauses were introduced by sub-SAT,and the number of symmetries was made with exponential growth in the solving process.In responseto this problem,static symmetry-breaking was used to carry out pretreatment of conjunctive normalform（CNF）,detect and break the symmetries therein.Consequently,the purpose of reducing the search path was achieved.The method of reduction to graph automorphism was used to detect all symmetries.After adding appropriate symmetry-breaking predicates（SBPs）,the search space was confined to non-symmetric regions of the space without affecting the satisfiability to the CNF formula.A SAT solver was then applied to the preprocessed CNF formula.Results of experiments show that this approach can reduce the runtime and speed up the solving process.
		2010 Vol. 31 (3): 318-322 [Abstract] ( 1078 ) [HTML 1KB] [ PDF 352KB] ( 1491 )

	323	*Strategy and simulation for switched reluctance motor converters to achieve soft switching*
		Meng Runquan, Wang Zhenmin, Bu Qinghua
		A novel soft switching strategy in the power converter of switched reluctance drive（SRD） was proposed.In the strategy,a kind of parallel quasi-resonant DC link was inserted between the DC power and the control circuit of the switched reluctance motor（SRM） windings,a shunt-wound capacitance was added to every SRM phase switch,and zero-voltage switch of phase switches was realized.Based on the introduction of topology and characteristics of strategy circuit,the zero voltage turn-on principle of phase switches was analyzed.Considering the common switch′s chop in the common switch converter,the controlsequence and resonant modes were analyzed.Simulations were implemented to investigate the influenceof the energy storage change of resonant inductor and different inductance value of SRM winds on resonance.The results show that the resonant waveforms will not be affected by the change of inductancevalue of SRM winds only if the appropriate resonant parameters are selected.The soft switchingperformances of phase and auxiliary switches are validated by experiments.
		2010 Vol. 31 (3): 323-327 [Abstract] ( 1703 ) [HTML 1KB] [ PDF 335KB] ( 1991 )

	328	10.3969/j.issn.1671-7775.2010.05.001
		Zhang Dengyin, Gao Dehua, Li Peng-
		In order to detect the Rootkits which hid in a system by tampering registry file,the common hidden technology of Rootkits and corresponding detection methods were analyzed,and the weaknesses of these detection methods were pointed out.Based on the analysis of format of registry files and the flow control for a typical registry operation,a new Rootkit detection method was designed and realized.The process of enumerating the registry keys in win32 system kernel was simulated,and valid keys of registry were obtained.Binary search tree algorithm was used to improve the detection efficiency in ergodic key value of registry.The results of experiments show that this method can detect the Rootkits which hide registry key effectively and quickly.
		2010 Vol. 31 (3): 328-323 [Abstract] ( 3432 ) [HTML 1KB] [ PDF 412KB] ( 2076 )

	334	*A model for representing reasoning about actions based on colored Petri net*
		Liu Yisong, Zhong Shan, Zhan Yongzhao
		In order to solve the problems in representing asynchronized concurrency,true concurrency and conflic,a new formalized representation model—CPNRAA net was proposed based on the colored Petrinets,which possessed strict mathematic model and could easily represent the asynchronization and concurrency.After that the states,actions and compound actions were formalized.A CPNRAA net system was provided by constructing the CPNRAA net for actions and compound actions and by adding a special place to save the action sequence.The method for generating action sequence was introduced and the actionsequence was obtained automatically in the proposed CPNRAA net.Finally,the case of CPNRAA net of sending coffee in the office was modeled and simulated,and the action sequence was automatically generated.The results show that the proposed CPNRAA net model possesses good feasibility and effectiveness.
		2010 Vol. 31 (3): 334-338 [Abstract] ( 1302 ) [HTML 1KB] [ PDF 403KB] ( 1442 )

	339	*Optimization of semantic MASHUP architecture applied in microlearning enivironment*
		Shi Zhiyuan, Volker Gruhn, Zhu Mingfang
		Considering the drawbacks during the syntax procedure in application of MASHUP,such as weak descriptive capability and lower reusability,a semantic realization methodology of MASHUP architecture under current microlearning environment was studied and optimized.Based on the analysis of intension and extension of microlearning model,in which learner was the organization center,it was demonstratedthat using MASHUP network aggregation architecture could effectively extract and integrate semantic-related microcontent.An advanced MASHUP architecture named Net-Node,in which resource group was automatically matched by subject,was proposed and evaluated.In this model,entire semantic encapsulation of microcontent in MASHUP applications under microlearning was completed by means of attribute routing and serial matching in the MASHUP net.
		2010 Vol. 31 (3): 339-342 [Abstract] ( 1360 ) [HTML 1KB] [ PDF 307KB] ( 1548 )

	343	*Theory of ECOSUNIDE technique and its practical application*
		Li Ang, Zhang Yanqiu, Li Yan, Diao Zhijun
		Based on the Ecological Superior Nitrification Denitrification（ECOSUNIDE） technique and unified dynamics,the dynamic equation and theory were analyzed,and the engineering experiments on ECOSUNIDE process were conducted.The results show that the treatment capacity of ECOSUNIDE system is 4 500 m^3/d more than that of A^2/O system in the same conditions.Effluent BOD,COD and NH3-Nare about 6,25 and 1.9 mg/L respectively at low temperature and carbon source.These indexes meet with the Class I-A criteria specified in discharge standard of pollutants for municipal wastewater treatment plant（GB 18918—2002）,the other indexes meet with the Class I-B criteria.The activated sludge was analyzed and compared,and the results show that the characteristics of the activated sludge are improved,with richer biological phases,darker and closer zoogloea,clearer flocs edges,and more obvious filamentous.
		2010 Vol. 31 (3): 343-347 [Abstract] ( 1232 ) [HTML 1KB] [ PDF 358KB] ( 1355 )

	348	*Treatment of high mass concentration coking wastewater using enhancement catalytic iron carbon internal-electrolysis*
		Pan Luting, WuU Jinfeng, Wang Jian
		The treatment of coking wastewater is very difficult because of its high mass concentration pollutant,complicated components and poor biodegradability.To solve the problem,catalytic iron carbon internal-electrolysis process was adopted in the pretreatment of high concentration coking wastewater.The effects of initial pH,sewage residence time,volume ratio of Fe/C and some other key factors on the treatmentwere explored.By orthogonal test,the optimized parameters of catalytic iron carbon internal-electrolysispretreatment of coking wastewater are determined as： influent ρ（CODin）=3 200～3 500 mg/L,pH=3,V（Fe）/V（C）=1∶1,hydraulic retention time=90 min.Under the above conditions,the removalrate of COD,phenol,sulfide,degree and NH3-N are 66%,75%,73%,80% and 34% relyspective,and its biodegradability（BOD5/COD） is also improved from 0.25 to 0.52.In addition,the reactivity is greatly increased.
		2010 Vol. 31 (3): 348-352 [Abstract] ( 1482 ) [HTML 1KB] [ PDF 320KB] ( 1694 )

	353	*Finite element simulation of laser-generated Rayleigh waves for detecting cracks on viscoelastic plate*
		Sun Hongxiang, Xu Boqiang, QIAN Rongzu
		Based on the theory of plane strain and the equations of dynamic equilibrium in the frequency domain,a finite element model for simulating laser-generated Rayleigh waves on the viscoelastic plate was developed.The effects of material viscoelasticity on the characteristic of Rayleigh waves were analyzed.The interactive process of reflection and mode-conversion of the Rayleigh waves on the surface-breaking crack of the viscoelastic plate was simulated in detail.Moreover,the position and depth of the surface-breaking crack were calculated.The numerical results show that the reflected Rayleigh waves have two components through the reflection of the laser-generated Rayleigh waves.The physical mechanism of the reflected waves RR and RS can be used to detect the position and depth of the surface-breaking crack.The study provides theoretical basis for detecting the surface-breaking crack on the viscoelastic material quantitatively.
		2010 Vol. 31 (3): 353-357 [Abstract] ( 1553 ) [HTML 1KB] [ PDF 347KB] ( 1524 )

	358	*Numerical modeling of laser-induced molten pool for laser interaction with metal material*
		Xu Boqiang, Wang Hao, Xu Guidong, Xu ChenGuang, Zhang Ziguo
		An axisymmetric numerical model of a laser-induced molten pool has been developed for a laser interaction with Al plate.Based on the mixture continuity equations,the coupled PDEs for laminar fluid flow and heat transfer were solved by the finite element method,taking into account the coupled effects of buoyancy,Marangoni force and the thermophysical characteristics with temperature variations.The temperature distribution,the molten pool shapes and fluid flow were computed for three cases： δγ/δT0,δγ/δT0,δγ/δT=0,corresponding to three different surface tension gradients.The numerical results show that the temperature distribution is similar with the Gaussian beam intensity,Marangoni flow is the main form of the liquid flow,δγ/δT plays a decisive role in the fluid flow of the molten pool,and fluid flow has a significant effect on the shape of the molten pool,which can not be ignored during laser processing.
		2010 Vol. 31 (3): 358-362 [Abstract] ( 1557 ) [HTML 1KB] [ PDF 338KB] ( 2109 )

	363	*Global sliding-model variable structure control for uncertain discrete-time systems*
		Cai Guoliang, Zhou Weihuai, Zheng Song, Wang Haoxiang
		A global discrete-time sliding mode controller is presented for the systems with parameter uncertaintiesand external disturbances.In order to reduce chattering,the boundary layer method using variable structure concept is applied.By choosing an optimal boundary layer width,the systems states reach sliding mode surface exactly in the shortest time and thereafter stay on without chattering on the condition that all the uncertainties are known.A disturbance compensator is constructed to ensure favorable robust stability to the close-loop system in the sense that unknown uncertainties are varying slowly,when the optimal design parameter is suggested.Simulation results have shown the effectiveness of the proposed algorithms.
		2010 Vol. 31 (3): 363-368 [Abstract] ( 1182 ) [HTML 1KB] [ PDF 323KB] ( 1492 )

	369	*Strong law of large numbers for three-order circular Markov chains*
		Yang Weiguo, Liang Peipei
		In order to study the strong limit theorems for circular Markov chains in nonhomogenous Markovchains,firstly,the definition of three-order circular Markov chains is introduced.Then by applyingthe limit property for functions of nonhomogenous Markov chains,the limit property for the frequenciesof occurrence of states for three-order circular Markov chains is established.Finally,the strong law of large numbers on the frequencies of occurrence of states for three-order circular Markov chains is obtained,which offers a theoretical basis for the applications of circular Markov chains
		2010 Vol. 31 (3): 369-372 [Abstract] ( 1295 ) [HTML 1KB] [ PDF 208KB] ( 1528 )

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