CHEN Minyou , ZHANG Xiaoju , LUO Ciyong , HE Wei
2009, 32(7):731-735. DOI: 10.11835/j.issn.1000-582X.2009.07.001
Abstract:In order to improve the error in image reconstruction caused by changeable positions of the electrodes in closed electrical impedance tomography, we propose an open electrical impedance tomography (OEIT) model using fixed electrode array. The problem was approximately assumed to be a virtual field by defining certain local sensitive area instead of solving the boundary problem in the whole electromagnetic field strictly. Modeling and simulation of OEIT have been conducted to define reasonable boundary parameters and electrode array structure. The finite element method is used for forward computation while Newton onestep error reconstructor is used for image reconstruction. The target position, area and conductivity change can be reflected by the relative change of the boundary voltage and the reconstructed image is clear. Better resolution and positioning accuracy can be obtained in the shallower surface of the body by OEIT, so it is valuable in clinical applications.
LI Nan , LI Baizhan , SHENG Yan , YU Wei , DING Yong
2009, 32(7):736-742. DOI: 10.11835/j.issn.1000-582X.2009.07.002
Abstract:A typical residential housing in Chongqing is taken as an example, which is with worse natural climate conditions and absent of wind resource. A feasibility study on improving the thermal environment by natural ventilation is analyzed based on the id chart. By the onsite tests,the indoor thermal comfort is evaluated based on the PMVPPD methodology. Better natural ventilation can not only save the building energy consumption, but also improve indoor thermal environment, especially in the rain and transition seasons, even in the urban area with poor wind resource.
WEN Tong , LEI Jie , PEI Chunlei
2009, 32(7):743-746. DOI: 10.11835/j.issn.1000-582X.2009.07.003
Abstract:A polygon particle model with discrete element method(DEM) is developed based on the Hooke’s law, in which the geometry change caused by the elastic deformation and features of material can be taken into account. A DEM programme is developed based on the proposed model and collision processes of elastic particles is studied with finite element method(FEM) and DEM. Comparing the result of DEM with that of FEM. When dealing with the problem of particles contact, the real deformation and the contact force variation of the particles can be presented more accurately with elastic deformable particle model, compared with that from traditional rigid particle model.
2009, 32(7):747-751. DOI: 10.11835/j.issn.1000-582X.2009.07.004
Abstract:The sky luminance distribution model is developed by information analysis methods with ant colony system. A new arithmetic is given to solve complex optimization heuristic algorithm. The coefficient values of sky luminance distribution function are obtained by optimization analysis with ant colony system and on which a set of practical software is developed. It can provide an intuitive and easy calculation. The model has higher precision, which can provide valuable results on highprecision and standard daylighting design.
YANG Xin , SHEN Zhixi , HUANG Xiyue , ZHAN Jianping
2009, 32(7):752-756. DOI: 10.11835/j.issn.1000-582X.2009.07.005
Abstract:For multiclass obstacles recognition for intelligent vehicle in urban traffic scenes, an improved Binary Tree Support Vector Machine (BTSVM) based on ensemble learning is presented. Based on the distributing probability and pattern diversity of each obstacle in urban traffic scenes, a compatible tree structure of BTSVM is designed. An approach based on AdaBoost ensemble learning is applied to reduce the transfer error and improve the accuracy and generalization ability of pernode classifier. The proposed method can efficiently recognize 6 kinds of normal obstacle patterns in urban traffic scenes.
YANG Yang , LIU Song , QIN Datong , HUANG Xiaorong
2009, 32(7):757-761. DOI: 10.11835/j.issn.1000-582X.2009.07.006
Abstract:A hydraulic braking system of the hybrid vehicle is designed based on braking force distribution and brake pressure coordination control strategy of integrated startor and generator(ISG) hybrid electric vehicle(HEV). Simulation model of hydraulic braking system has been established using AMESim software platform. Dynamic performance simulation and analysis to the key components and systems are performed. The results verify the correctness and feasibility of system program and provide evidence for designing and optimizing of HEV braking system.
HE Yulin , ZHANG Ligang , HAN Dehai , DU Jing
2009, 32(7):762-765. DOI: 10.11835/j.issn.1000-582X.2009.07.007
Abstract:Using large finite element software MSC.Marc/Mentat, the contact analysis of bolted joints parts between the hub and the bearing of wind turbine is conducted for the contact stress suffering from the practical work load. The maximum stress acted on the bolt is obtained, and a detail contact analysis for this bolted joints parts is given. The accurate stress of bolts, bearing and hub is calculated. The FEA contact results are consistent with the theoretical calculation results, and the strength of materials meets the requirements, which means the structure is safe.
LI Yinong , WANG Yibao , LUO Zhiqian , WANG Jian , LI Hongjun
2009, 32(7):766-769. DOI: 10.11835/j.issn.1000-582X.2009.07.008
Abstract:Based on the analysis of dynamics method of pneumatic transmission, the mathematic model of air brake Load Sensing Proportional Valve (LSPV) is established by fluid servo control theory. The air brake LSPV of one All Terrain Vehicle (ATV) is simulated with the platform of advanced modeling ervironment for performing simulations of engineering system(AMESim), then the input and output pressure characteristic curve of the valves are obtained. The characteristic curve shows, with the load increasing, the pressure adjustment point of Load Sensing Proportional Valve (LSPV) moves up. When the pressure reaches into the pressure adjustment point, the increase rate of output pressure is less than the increase rate of input pressure, so that it can effectively prevent the lockup of the rear wheel precede the front wheel. The result of the simulation is consistent with the experiment result. The validity of the model is verified, which provide foundation for the simulation of the air brake elements and brake system.
2009, 32(7):770-774. DOI: 10.11835/j.issn.1000-582X.2009.07.009
Abstract:A Chinese speech (mandarin) database was established for speakers gender recognition. A combination method is proposed for gender recognition of speakers based on support vector machine and Melfrequency cepstrum coefficients (MFCC) for classification and feature extraction respectively. The comparative result shows that the accuracy of SVM is 98.7%, which is better than other methods.
LIU Zhenjun , HU Jianjun , WEN Shao , ZHANG Zhilong
2009, 32(7):775-781. DOI: 10.11835/j.issn.1000-582X.2009.07.010
Abstract:AMT (Automatic Manual Transmission) comprehensive performance test is one of the main means to develop and evaluate AMT. An overall scheme of the data acquisition and communication system for AMT comprehensive performance testbench is proposed according to the requirement of the testbench, and a communication network of data acquisition and communication system is built. The hardware and software of data acquisition system are designed. The experiments show that the system meets the requirement of data acquisition and communication system for AMT comprehensive performance testbench and it lays a foundation for AMT comprehensive test research.
LIU Yulin , ZHANG Xianyu , LUO Yingguang
2009, 32(7):782-786. DOI: 10.11835/j.issn.1000-582X.2009.07.011
Abstract:A novel channel estimation algorithm is proposed for MBOFDM Ultra WideBand systems based on tap detecting by exploiting the sparse property of channel impulse response. The channel parameters are estimated using the DFT algorithm based on cyclic convolution property of the receive signals. The nonzero taps are detected by exploiting the matching pursuit(MP) algorithm. The new estimated channel parameters are obtained by forcing the zero taps to zeros. Simulation results demonstrate that it has better MSE (mean square error) performance for the four channels proposed by IEEE. Especially for CM1 and CM2 channels, the performance of the algorithm has been greatly improved.
YAN Bo , LI Wenyun , ZHANG Hongyan , ZHOU Song
2009, 32(7):787-792. DOI: 10.11835/j.issn.1000-582X.2009.07.012
Abstract:The dynamic balance equation of the system is set up by means of the Hamilton variational principles with the constraint conditions of the clamp points of spacers in the subconductors by the penalty function. The numerical simulation for galloping of twin bundle conductors is achieved with the time integral by Newmark method and the NewtonRaphson iteration solution for nonlinear equation. The validity is approved with simulation for the galloping of horizontal and vertical icing twin bundle conductor. The difference of aerodynamic loads, which is due to the impacts of wake flow of windward subconductor on lee subconductor, on the individual subconductors can be considered with the proposed approach. It is appropriate for further study in the field of bundle conductor galloping.
YAO Qiang , CHANG Tao , LIU Yong , QIU Ni , ZHANG Xiaoxing
2009, 32(7):793-797. DOI: 10.11835/j.issn.1000-582X.2009.07.013
Abstract:The composition of SF6 decomposition products is directly associated with the safe operation of equipment. Through GCFTIR coupling technique,the SF6 decomposition products are divided, the qualitative analysis is made with FTIR to the outlier,and spectrogram was processed with subtract and searched the analogous one. Above data is used to generate the tridimensional atlas of infrared spectrumabsorbanceGC holding time. Single gas analysis is compared with local measurement, the foregoing method can make the qualitative analysis and quantitative analysis for the decomposition products, the fault features detected by gas composition and chroma is anastomotic with the actual fault, the result indicates that this method can be used in GIS fault diagnosis.
CAO Shugang , LIU Yucheng , LIU Yanbao , LI Yong , WANG Jun
2009, 32(7):798-803. DOI: 10.11835/j.issn.1000-582X.2009.07.014
Abstract:The existing section function for mining subsidence prediction has several shortcomings, such as complex expression, uncertainty of coordinates origin and parameters in application. The features of observing data in the ground subsidence of rectangular goaf are studied and a new fit function of main section is proposed for mining subsidence prediction.This new function has some merit that the mathematical formula is simple and the parameter is also easy to identify in practices. It is proved that the results of this new function is fit well with onsite survey .
WANG Houhua , HUANG Chunyong
2009, 32(7):804-808. DOI: 10.11835/j.issn.1000-582X.2009.07.015
Abstract:The numerical simulation with FLUENT software is addressed for the natural convection heat transfer under the conditions of different airlayer thickness with 6 mm,9 mm,12 mm,14 mm and 16 mm. The heat transfer rate is compared with that by heat conduction. Gas types, Rayleigh number (Ra),the relative thickness of airlayer,δ/H,and the surface (ΔT) are main factors for natural convection heat transfer. The natural convection heat transfer could be approximately regarded as the pure heat conduction in the conditions of above airlayer thickness. The heat transfer coefficient of the insulating glass with simulation is approximate to that with empirical calculation.
QIN Shihong , CAO Huanming , NI Xiaojun , LUO Wankang
2009, 32(7):809-814. DOI: 10.11835/j.issn.1000-582X.2009.07.016
Abstract:To study the eccentric compression performance of autoclaved flyashlime brick masonry, and validate the applicability of current code’s calculation method, static tests on 36 eccentrically loaded puncheons of standard autoclaved flyashlime solid brick and KP1 type perforated brick with circular holes masonry are carried out by applying eccentric load on the top of the specimens. The bearing capacity of eccentric compression is analyzed using planesection assumption and ideal stress/strain curve. The features and shapes during the process of failure are obtained and the eccentric compression impact factor formula is also obtained by regression analysis of experimental data. With eccentricity increasing, cracking load and failure load are gradually decreased, and the failure features gradually change into large eccentric compression from axial compression. Most test values of bearing capacity under eccentric compression are higher than code calculating values. The average strain distribution in the section is in accordance with the planesection assumption. The theoretical analysis method used is feasible, current code’s formula can be used to calculate the bearing capacity of flyashlime brick masonry under eccentric compression.
REN Song , JIANG Deyi , YANG Chunhe
2009, 32(7):815-822. DOI: 10.11835/j.issn.1000-582X.2009.07.017
Abstract:Based on the new probability integral 3D model for forecasting the solution mining subsidence, the transfer rule of superincumbent strata in mining subsidence is studied and a prediction model of stratification transfer for mining subsidence is developed. The model can take into account of the impacts of features of different rock strata on mining subsidence and improve prediction precision of irregular goaf. Based on the situation that it’s hard to get the analytical solution of the model with triple integral, the numerical algorithm of the model is supplied. With the superposition principle theory, a prediction model of multicavern mining subsidence is developed. With the application in ground subsidence prediction of oilgas storage in Jintan, it proves that the transfer prediction model holds higher precision than those of traditional models
TANG Zhide , XIE Di , FENG Lixiao , WU Mingpeng
2009, 32(7):823-828. DOI: 10.11835/j.issn.1000-582X.2009.07.018
Abstract:FEMlab3.3(Finite Element Model Lab) is used to develop an energy delivery model for implanted devices. We designed three different shape electrodes made of Ag to enhance current transmitting efficiency. Several voltages were used for pursuing perfect goal. With the body safety current, we can get the results with a current transmitting efficiency of 20% and the energy delivery efficiency of 4%~9%. It is clear that the high energy delivery efficiency can be obtained and the results provide references for further study of energy delivery through body conduction.
DENG Anfu , ZHENG Bing , ZHOU Xiaoyi
2009, 32(7):829-833. DOI: 10.11835/j.issn.1000-582X.2009.07.019
Abstract:Based on basic theory of numerical manifold method, effects of cover displacement functions for the stiffness matrix is analyzed with the relationship between the cover displacement function and the formation of the stiffness matrix. The increasing speed of matrix element value has relation to the values of absolute coordinates in cover displacement function. An improved function is adopted for better solution to solve partial oversize problem of stiffness values in the stiffness matrix with the highorder cover displacement function. The validity of the proposed approach is approved with case study.
YANG Chunyu , CHEN Yonggan , ZHANG Qingwen
2009, 32(7):834-838. DOI: 10.11835/j.issn.1000-582X.2009.07.020
Abstract:With the measurement of reflection spectrum and the experimental measurement of illumination observing angle, color temperature of light source, effects of field viewing angles, it is found that the color of facing materials have relation to light incidence and observing angle. The chroma number varies with the changing of light incidence and observing angle based on the features of facing materials. The chroma number has more fluctuation with the angle close to mirror reflection direction while it is more steady with other angles. Besides, the mirror reflection phenomenon is not obvious for subbrightness facing tile. The color temperature of light source affects material color and the chroma number varies with the incidence changing, etc. All of these have provided fundamental for quantitative study of architecture color design.
CHEN Zhonglin , MA Yulin , HU Yingkui
2009, 32(7):839-843. DOI: 10.11835/j.issn.1000-582X.2009.07.021
Abstract:In order to find out a space sense indicator that can present the real appearance of human and natural in urban lighting environment, three common used indicators are studied, which are ratio of vertical illuminance to semicylindrical illuminance, ratio of vertical illuminance to horizontal illuminance and ratio of average cylindrical illuminance to horizontal illuminance.An onsite test is taken at Three Gorges Square Pedestrian Street of Chongqing. The variation law of ratio of vertical illuminance to horizontal illuminance is approximate to ratio of average cylindrical illuminance to horizontal illuminance, which varies with the changing of measure point location and reach maximum at the axial central section of pedestrian street between two streetlamps. The change of ratio of vertical illuminance to semicylindrical illuminance is small correspondingly and it is more appropriate to be as a lighting quality indicator with space sense for urban illuminance environment.
LI Shaoming , ZHANG Jiayan , XIE Fuchun , JI Ping
2009, 32(7):844-847. DOI: 10.11835/j.issn.1000-582X.2009.07.022
Abstract:It is difficult to measure the surface temperature of iron ore directly. A method is put forward to handle this problem by using softsensing technique. This online measurement method is used to replace the Lagrange interpolation offline method to estimate surface temperature. The method used LM optimum algorithm to build up ANN soft sensor model combined with offline learning neural network to establish the correlation between input variables and target variables, to achieve the surface temperature on line detection. The results of simulation and experimentation indicate that the method is reasonable and feasible.
SONG Yuchuan , MA Zhihua , WANG Yongjing , JIANG Linghui
2009, 32(7):848-853. DOI: 10.11835/j.issn.1000-582X.2009.07.023
Abstract:Effective information strategy and information systems are important for the development of automobile manufacturing enterprises. In complicated and dynamic business environment, information systems planning (ISP) faces the problem of lacking integrated optimization of enterprise strategy, business strategy, and IT strategy. A hierarchical information system planning model is developed for automobile manufacturing enterprises. A planning approach is proposed to make the information system continuously mating the enterprises' strategy. The proposed studies were applied to agile ISP of an automobile manufacturing enterprise with satisfied result.
LUO Yanfeng , QU Sheng , SUN Jiaoxia , WANG Yuanliang
2009, 32(7):854-858. DOI: 10.11835/j.issn.1000-582X.2009.07.024
Abstract:A novel pHsensitive degradable hydrogel based on ethylenediaminetetraacetic dianhydride (EDTAD) was synthesized.EDTAD reacted with butanediamine through Nacylation ringopening polymerization of anhydride groups to give a linear copolymer (pEDTADBDA) with carboxyl groups on its side chains and amide groups on its backbone. pEDTABDA was dehydrated between those carboxyl groups on its side chains and amide groups on its backbone at 160℃ with phosphoric acid as a catalyst. A copolymer was produced containing imide groups (pEDTADBDAImide). pEDTADBDAImide was crosslinked by BDA via Nacylation of the imide groups, yielding the desired network polymer with pendant amino groups (BDAcrosslinkedEDTADBDA). BDAcrosslinkedEDTADBDA is a promising hydrogel for drug controlled release integrating such advantages as degradability, good biocompatibility and pHsensitivity. FTIR and ninhydrin reaction are employed to qualitatively and quantitatively characterize pEDTADBDA and BDAcrosslinkedEDTADBDA.