2015 volumne 36卷 Issue 04
JIANG Jian-dong1 ,ZHANG Hao-jie1 ,WANG Jing2
Abstract: To further improve the accuracy of power load forecasting,on the basis of the analysis of affectingfactors of power load, a combination prediction model based on HHT is proposed. This model uses EMD algo-rithm to decompose the original load sequence. Thus, a stationary sequence of different frequencies,which ismore predictable than the original load sequence,can be obtained. Based on the components of different fre-quencies,according to the characteristics of the different frequency of subsequence ,the RBF neural network ,BP neural network and time series model are selected to forecast while considering the influence of temperatureon the load. Then,a new combined model can be achieved. The experiment shows that the proposed modelcan effectively improve the accuracy of load forecasting.
Ll Jian-yong1,ZHAO Feng2,DING Qing-qing1
Abstract: Stochastic delay and packet loss decline the performance of networked systems and even make it un-stable. This paper proposed a novel stochastic delay compensation strategy based on model reference adaptivecontrol and dual Smith predictor. First,by introducing a joined Smith predictor at the controller and actuatorterminal end , the stochastic delay compensation problem is transformed to the model matching problem. Then,a model reference adaptive controlled is designed to make the Smith predictor model and the real system modelmatch with each other and to achieve the full compensation of random delay. The simulation results show thatthe proposed strategy can effectively compensate the network delay and has better real-time property.
ZHU Xiao-dong,LIU Dan,Ll Guang
Abstract: In view of a new type of hierarchical fuzny system,a hybrid optimization algorithm is proposed inthis paper. The antecedent parameters of each fuzzy unit model are estimated by the particle swarm optimiza-tion algorithm,and the recursive least square algorithm is used to determine the parameters of consequents.Experiments on the well-known Box-Jenkins set data and the chaotic Mackey-Glass time series are carried out.The proposed hybrid optimization algorithm is compared with the fruit fly optimization algorithm and the inva-sive weed optimization algorithm. The result of experiments shows that the hybrid optimization algorithm canimprove the accuracy of the hierarchical fuzzy system model.
SU Shi mei1,LV Xue yang2
Abstract: A segmentation method based on the wavelet analysis is proposed in this paper for segmenting visi-ble components from the bone marrow cell. Firstly,the wavelet transform is used to erase the effect of defocus-ing.Secondly,G component is chosen as clustering the information of characteristic parameters by using thethreshold multi-scale wavelet analysis,which is combined with saturation component according to different dis-tribution characteristic of leukocyte nucleus to construct a transpositional image named STG. The nucleus areextract by thresholding the image.Ultimately,it can provide an optimal initial clustering centers for K-meansclustering method to segment the red blood cells and the white blood cells from the background as well as sepa-rate them from each other. Through comparative analysis and algorithm testing,this method can effectively o-vercome the difficulties of complex components,poor discrimination and complicated defocusing during thecells segmentation ,the accuracy rate reaches 94.15 % .
CA0 Yuan,WEI Qiao nan
Abstract: This paper studies the control system of diode clamped three-level inverter in STATCOM. The vari-ation of inductance can affect a control method. The paper proposes a control method which can ignore the in-ductance and studies how to stabilize capacitive voltage difference in VSVPWM on 60° Coordinate Frame. Thesimulation verification is combined with simulation model. Finally,the simulation verification of the systemwhich is based on decoupling control is built with the system simulation model. The experimental platform usesDSP2812 as the main control chip of minimum system. The experiment results show the accuracy of the theo-retical analysis and simulation performance.
LIU Ai ling1,MA Huan2,Ql Shu kang1
Abstract: Forced-circulation evaporators (FCE) are typical muli-input multi-output strong coupling nonlinearsystems and the conventional linear system controller cannot guarantee the high performance of the system. Inthis paper,a nonlinear dynamic model was constructed based on the analysis of the construction and engineering process of FCEs. Then,with the inverse system method,a state feedback controller was proposed to real-ize the linearization and decoupling. Finally , for the obtained pseudolinear system,an optimal controller wasput forward. The simulation results showed that compared to the conventional PID controller,the proposednonlinear controller can effectively improve the dynamic performance of FCEs
Wang Hong-kai1,2,Ll Hua1,Ll Ming-xue1,GUo Qing-qing ,Ll Jing1,LIA0 Zhong-ling,SU Yuan1
Abstract: A heat-resistant flexible adhesive cured at room-temperature was synthesized with epoxy resin,pol-ysulfide rubber and organosilicone as the first component,polyamide as the second component,and addition ofdifferent modified fller. The modified epoxy resin adhesive has the satisfactory properties of rapid curing rateat room temperature and a suitable toughness and heat resistance. When the adhesive was cured for 72 hours atroom temperature,the shearing strength can be up to 19.84 MPa,the heat resistance can up to 160℃,andthe instantaneous temperature can be over 250 ℃. The modified epoxy resin adhesive has been characterizedby FT-IR,1H NMR,TGA and XRD,and the result showed that the Si-O group improved greatly the thermo-stability of the modified epoxy resin.The XRD analysis showed that the modified 20 diffraction peak was great-ly weakened at 18 °,which indicated that the modified filler can increase the cured degree of modified resinand the cured reaction time. The experimental result in this work provides the theoretical founclation for thesynthesis and application of modified organosilicone epoxy resin.
Ll Wen1,LIU Chun-xia1,YU Yu-zheng2,ZHANG Hua1,CHEN Shui-ku1,ZHANG Fang-jie1
Abstract: This paper studies the chemical resolution process of Pregabalin.Process for resolving racemic Pre-gabalin to S- Pregabalin by using S- mandelic acid as the resolving agent, the content of each component in theresolution process were determined by HPLC method. The optimum resolution conditions were obtained by theinvestigations of the rule in the content variations of different components under different conditions and veri-fied by the further tests. The optimum resolution conditions obtained from this study have good repeatability ,and the content of Pregabalin could reach more than 99.5% which fully meets the requirements of Pharmaco-poeia, the amount per batch of qualified products is not less than 100 g. This study provides a valuable theo-retical foundation for the industrialized preparation of Pregabalin.
WANG Wei-shu1, SHAGN GUAN Shan-shan1,LU Tong1 ,YANG Zhi-feng2 ,ZHENG Chun-xiong1,CHEN Gang1
Abstract: Based on FLUENT6.3 software,the simulation and analysis were applied to the optimization designof splitters in Selective Catalytic Reduction ( SCR ) denitrification system for a 600MW coal-fired boiler. Theresults show that because of variable cross-section and deflection in flue,flow field in the system appears non-uniform severely when there is no splitters. The velocity difference on two sides of the section at AlG lowerreaches is up to 15 m/s,the velocity deviations in the reactor inlet is 31.25% , and the flow field is poor intail flue,which affects the operation of downstream equipments.Reasonable splitters can improve flow field influe effectively. After equipping the transition pipe of the inlet with two group of longitudinal splitters, the ve-locity deviations in section at AIG lower reaches is reduced to 15% and in the reactor inlet is reduced to 13% .Splitters in elbow is equipped with an extension for guiding,which have a good effect on homogenization of thedownstream flow field.
ZHANG Ya-dong,JIA Jin-feng
Abstract: Using the chloro-methylated polystyrene-divinyl benzene cross-linked resin ( PS,chloromethylatedbead ) as starting material,using ethanediamine(EDA ),ethanolamine(ETA ) or ethylene glycol ( EG) as trussarm,the modified PS was prepared by the reaction of truss arm and PS,and then,cyanuric chloride was load-ed to the modified PS by substitution reaction and get polystyrene chlorotriazine resins ’The structure of the pol-ystyrene chlorotriazine resins of the three truss arms were analyzed separately by IR.The results indicated thatthe truss arm with amino was more conducive to modification of PS and conducive to load cyanuric chloride.Considering the quantity of the load of the object,the modified PS by EDA is better than the modified PS byETA and EG,the weight increase ratio of the substitution reaction is 28.1 %,the capacity of loading is 1.48mmol/ g and the chlorine content is 5.9%.The prepared polystyrene chlorotriazine resins can be used as anactive intermediate,which can be made into many functional media by derivatization.
WEI Xin-li,YAN Yan-wei,MA Xin-ling,MENG Xiang-rui,LI Ming-hui
Abstract: For the Organic Rankine Cycle System ( ORCS)using R245fa as refrigerant, three types of evapo-rators are frequently-used, namely the flooded type,the falling film type and the plate type.Based on the ex-changer design and rating heat exchanger module in Aspen,this paper performed structure design and perform-ance analysis on these three types of evaporators. Under the same heat transfer medium and operating parame-ters,comparative analysis are made on size,cost and overall heat transfer factor of the evaporators.lt ’ s foundthat the plate type evaporator is most suitable for the ORCS;the effects of the corrugated inclination angle(β),plate thickness ( d) and plate spacing (l) on the evaporating, overheating and preheating of refrigerantsin the evaporator are analyzed through numerical simulation,thus the correlation between plate structure andthe heat transfer coefficient,pressure drop is concluded.
WAN Ya-zhen,LIU Ya-nan,CHEN Di
Abstract: PTA supported catalyst was prepared by dip roasting method for the synthesis of 2-(4’ -ethyl benzoyl) benzoic acid (BEA) from phthalic anhydride and ethyl benzene as raw materials and chlorobenzene as solvent.The experimental results showed that when the load of PTA was 30%(mass fraction) and the roasting temperature was 300℃, the catalytic activity of PTA was more than doubled with SiO2 as the carrier.The effects of XRD on loading capacity and NH3-TPD on calcination temperature were analyzed. Ft-ir and BET were used to characterize PTA/SiO2 catalysts.The reuse performance of PTA/SiO2 catalyst was investigated, and the results showed that the original catalytic activity of PTA/SiO2 was still maintained after repeated use.
ZHAO Hong-liang,KONG Ya-ping,LIU Zhi-peng
Abstract: We added rare earth and titanium in Al-Mg-Si alloy,and the influence of rare earth and titanium onthe microstructure and properties of Al-Mg-Si conductive material were studied in this paper,with the opticalmicroscope,scanning electron microscope,DSC analysis on the microstructure of alloy,and testing the per-formance. The results show that,RE and Ti both have refining effect on Al-Mg-Si conductive material. Whenthe content of RE is more than 0.3% and the Ti is more than 0.15%,the phase Al Ti,Ce will form in Al-Mg-Si alloy,consuming a large amounts of Ti and Ce,which has an unfavorable effect on the mechanicalproperties and electrical conductivity of the alloy.
Ll Sheng-li,HU Ya-nan,DU Dao-qing,WANG Dong-wei
Abstract: Based on the long-span suspension bridge,and by means of the computational fluid dynamics soft-ware fluent,three different turbulence models such as the standard h-s model,RNG k-g model and SST mod-el,have been used to recognize the aerodynamic coefficients of catwalk in the condition of different windspeeds,wind attack angles and Reynolds number with a ventilate rate of catwalk.The results of CFD identifi-cation are compared with the corresponding results of wind tunnel tests.Comparing the results of numericalsimulation with those of wind tunnel test,it is proved that the variation of the drag coefficients is smaller withthe different Reynolds number,but that of the lift coefficients is bigger. So the appropriate Reynolds number isvery necessary for the catwalk numerical simulation.The results show that the SST model for CFD method ofthe catwalk section is reasonable model,and the ventilate rate of simulation for catwalk is feasible.
XU Xiao-dong,LU Yang,MAO Hang-yu,LIU Jin,YANG Qi
Abstract: This paper uses the mixture to study its dynamic shear modulus and equivalent damping ratio underthe different vertical loads and different tire particles content through horizontal cyclic simple shear test.Theresults show that when the vertical load on the mixture between waste tire particles and sand increases, its dy-namic shear modulus increases and its equivalent damping ratio decreases. The dynamic shear modulus and e-quivalent damping ratio of mixture is not a monotonous variation with the addition of tire particles content. Inthe test,the dynamic elastic modulus of the mixture between tire particles in small size and sand is relativelysmall and its equivalent damping ratio is relatively big,which can provide a reference in engineer applicationsfor the mixture between waste tire particles and sand.
DU Si-yi,SHI Lei
Abstract: Field static load test of pile group foundation is difficult to carry out because the limitation of fundsor equipments. At the same time,the bearing capacity mechanism of pile group foundation and interaction be-tween piles and soil is complex,there are still large gaps between the theory research and practice. In the pa-per mechanics characteristics of pile group foundation under vertical load were researched by the local testingand computer numerical value. Some solutions were educed that the bearing capacity of pile group foundationwill increase while the pile spacing increases, but the trend is very weak while S >5D.The difference of stressbetween piles in different positions will decrease while the pile spacing increases. The stress distribution on thepile top tends to be uniform with the increase of load.The bearing capacity of pile group can increase as pilelength increases,when length-diameter ratio L/D =20 ~30,The bearing capacity of pile group is greater andthe expense is lower.
LUO Lie-ri1,2,ZHENG Jun-jie2
Abstract: The deformation characteristics and overall stability of high embankment under traffic load havebeen widely studied in recent years. Based on numerical simulation method ,the response of embankment un-der dynamic uniform loads acting on the embankment surface is studied. Finally , the impacts of traffic loads’amplitude,frequency and running interval on the embankment response are analyzed. According to the re-sults , the settlements of embankment surface under dynamic traffic loads grow with the cycle index, but the in-crease percentage of deformation diminishes gradually to a stable value. The maximum settlement of embank-ment surface increases with the increment of traffic load’ s amplitude,frequency and the decrement of runninginterval.
WANG Lei1,2,MA Jiang2,YANG Zhi-gang1,ZHANG Wen-bo1,LIU Yong-bo1
Abstract: Small square muffler need to be developed for laden or towing vehicles with limited chassis layoutspace. The internal structure of muffler is gradually modified based on theoretical and numerical simulations,and aerodynamic performance and acoustic performance of each modified configuration are analyzed and re-searched to obtain the corresponding pressure filed,velocity field and temperature filed,by which to investi-gate thoroughly the resistance losses and noise characteristics and explore the effects of structural factors on theperformance of exhaust muffler. Four configurations of muffler are progressively optimized and a small squareconfiguration with insert tube connecting perforated expansion tube is ultimately designed. By bending the gasexhaust pipe and insert tube to decelerate gas exhausting,the insert tube is connected with the perforatedtube. The greater the diameter of the perforated tube is,the rapider the expansion and deceleration of high-speed gas inside the tube will be, to avoid the direct blowing of gas against wall surface. The airflow inside themuffler is improved to prevent the impact stress of airflow against wall surface concentration.
XIE Shao-bo1,2,LIU Xi-bin2,LI Si-guang2,WANG Jia2
Abstract: The power-train of APU including the engine and generator for a range-extended electric vehicle iscompared to get the minimum curve of the fuel consumption. The forward vehicle model is built on the Matlab/Simulik. Two control strategies of the output of the APU including the constant power working point and pow-er-follow are analyzed based on the Chinese classic urban driving cycle. The results show that the reasonablemach of the engine and generator can improve the vehicle ’s fuel economy and the fuel consumption is grownwith the power-follow mode when the APU outputs a wider range of the power.
FANG Hong-yuan1,2,Ll Jian1,ZHONG Yan-hui1,2,WANG Fu-ming1,2
Abstract: Ground Penetrating Radar ( GPR) has been widely applied in pavement quality detection. Thick-ness and dielectric constant of pavement structure can be obtained by inverse analysis of GPR echo signal. Theprecise and efficient numerical model of electromagnetic wave propagation in layered pavement structure is akey for inversion. The precise integration method ( PM) is developed to simulate GPR wave propagating inlayered structure in this paper. The numerical results show that simulated waveform fits well with measuredsignal,such as amplitude,time delay. In addition,the proposed method can save 40% CPU time comparedwith the traditional FDTD method.
LI Fei-ran
Abstract: Based on material nonlinear FEM and multi-convergence criterions,the new super wide " 321" pre-fabricated highway steel bridge was studied. The results show that the second stability coefficient of the extrawide "321" prefabricated highway steel bridge is small,which means the structure is not safe. The secondstability coefficient will be greatly improved, when a support is set at the mid-span. To avoid the local yieldprecedes the whole,the support should be set at the studdle position. The second stability coefficient is almostlinear increase within three supports by criterion [ and ll,but under criterion Ⅲ it does not significantly in-creased when the mid-span supports above two. ln application,the second stability coefficients will not in-crease when the number of mid-span supports is above two.
LIN Hong-liang1,2,YU Qiang1
Abstract: In the process of driving cycle construction,experimental data ’s analysis and processing will di-rectly affect the accuracy of driving cycle. Due to the complexity of urban road traffic structure and vehicle ’sspecial operating mode,fuzzy clustering method is introduced to analyze vehicle ’s typical motion data of Xi’an urban road traffic in order to establish driving cycle which is closely related to vehicle’s running state androad traffic flow. After average speed and speed standard deviation fuzzy clustering,following results arefound,sedan’s driving states on Xi’an urban road are divided into congestion running state ,steady flow run-ning state and free flow running state three categories. Furthermore,combining classification method withshort-stroke method,sedan ’s representative driving cycle in Xi ’ an city is built and verified. The resultshowed; the relative error between Xi’an representative driving cycle constructed by furzy clustering methodand experimental data is small,which would reflect the vehicle’s actual running state.
WU Su-zhen1,2,HE Wei-dong1
Abstract: In view of the quantity of cycloidal gear modification,tooth contact deformation and the effects ofthe pin gear bending deformation,the contact stress between the pin gear and the various cycloidal gears iscalculated by Hertz theory. Based on the meshing principles of cycloid pin gear planet transmission,the RVsecond-level finite element model of pin-cycloid meshing transmission is accurately established by using the fi-nite method. According to the actual working condition of fixed pin gear and cycloidal gears outputing,thenodes in the outer ring of the pin gear are constrained,and the rigid beam is employed to simulate the planeteasel output gears. Meanwhile,the rigid cell is employed to simulate the eccentric shaft crank. The hinge linktechnology is employed to simulate the rotation of crank relative to cycloid pin gear hole. Based on the actualworking condition of the constrained and simulated bearing of the bearing bore,a torque load is applied in theoutput unit centroid and the cycloid-pin gear contact nonlinear analysis is further employed to get stress, straimcontours of the eycloidal gear. Comparative analysis of the results of theoretical calculation and finite element a-nalysis offers a theoretical basis for optimal design of cycloid gear and the effective method of numerical simu-lation.
Ll Da-lei,DAI Chao-lei,Ll Feng
Abstract: The beam membrane structure of the single-layer spherical reticulated shell is analysed,and thestrength and local stability of reticulated shell structure design criterion are determined according to the failureforms of shell. The fluid solid coupling analysis of wind field and structure field is used through the finite ele-ment analysis software,and the section size optimization of the member is got by optimizing design.Through themulti point load test of the prototype of reticulated shell structure,the maximum displacement curve changeswith the load is obtained. Meanwhile,the test results and the simulation results are compared and analyzed ,and the simulation calculation model is verified,providing theoretical basis for the design and analysis of thesame type of single-layer spherical reticulated shell.
ZHAO Jin-chao,ZHU Hao-cong,SHEN Zhen,LI Hong-chan
Abstract: With the increasing amount of digital image data,image texture feature extraction has become a keystep of digital image processing. As an excellent massive data processing and storage capacity of the opensource cloud platform,Hadoop provides a parallel computation model MapReduce,HDFS distributed file sys-tem module. In this paper,we firstly introduced Hadoop platform programming framework and Tamura texturefeatures. And then,the image texture feature extraction was carried out on the Hadoop platform. In theprocess,every Map task corresponds to an image file, every nodes work at same time.The comparison resultsshow that number of nodes have no influence about the processing time,when we have little images and theimage has low-resolution. On the contrary,Hadoop paltform is more effective.
ZHOU Tong1,2,LI Yu-xuan1,YANG Zhi-yong1,2,SUN Di-hua2
Abstract: In order to describe the traffic phenomena more actually,based on the full velocity difference(FVD)model,a new car-following model,which considers the influence of the vehicle’s mechanical inertiaeffect,is presented. According to the control theory , the stability condition of traffic system is obtained. Thesimulation results are compared with that of the FVD model. It ’s observed that the proposed model can over-come the deficiency that the acceleration of leading vehicle of motorcade instantly jump,and can simulatemore practical traffic phenomena,such as stop-and-go,etc.. Therefore, the proposed model can describe theactual traffic phenomenon more precisely than FVD model,and support theoretical direction for formulation ofvehicle intelligent control strategies.
ZANG Jia-jie,LIU Ping,XU Han,CHEN Rui-ke
Abstract: This paper introduces a high frequency induction heating power supply based on MOSFET. A5kW/100kHZ prototype with power MOSFET as power switch is made.The power supply adopts the PDMpower control mode. And the resonant circuit uses series resonant so that the system can effectively overcomethe influence of load parameters change during heating process and keep MOSFET always woks at zero voltageswitching state.The inverter circuit,the power supply control circuit are researched and tested. The experi-mental conclusion showed that PDM and series resonant can meet the demand of low power high frequency in-duction heating power supply well.
WANG Zong-jiang1,YANG Shu-hui2
Abstract: Cloud computing provides four deployment models:public cloud,private cloud,community cloudand hybrid cloud.Generally,resources available in a private cloud are limited,thus the cloud users have torent resources from public clouds. This requirement means that cloud users will incur extra costs.More andmore enterprises choose the hybrid cloud to deploy their applications. In the hybrid cloud,in order to mini-mize the cost of using resources,it is also important to satisfy QoS for user. Therefore,this paper proposes re-sources allocation algorithm for hybrid cloud users who want to minimize the resource cost and ensure QoS sat-isfaction. The empirical results show that resources can be allocated by our algorithm in a way that satisfiesboth the user QoS while keeping operational costs low.
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