PENG Chenglin , XIA Lu , HOU Wensheng , WANG Xing , ZHENG Xiaolin , YIN Zhengqin
2009, 32(8):859-863. DOI: 10.11835/j.issn.1000-582X.2009.08.001
Abstract:A chip with smaller size and higher pixel density was designed to increase the chip’s pixel density in subretinal prosthesis. This chip was designed on 0.35 μm standard CMOS(complementary metal oxide semiconductor) technology of CHRT company, while the double inverter relaxation oscillator was chosen as the basic pixel circuit. By creating layout on Cadence software, the circuit was debugged and simulated. The experiment results show that the pixel circuit provide effective pulse signals whose values and frequencies can vary with photocurrent to stimulate retinal nerve cells. For the simulated layout, the pulse width was 0.26 ms, the frequency was 18~503 Hz, the pixel size was 65 μm×65 μm, and the chip size was 1.1 mm×1.1 mm. All of the parameters can satisfy the requirement to stimulate retinal nerve cells in physiology. The experiment results provide a good foundation for the following research.
2009, 32(8):864-868. DOI: 10.11835/j.issn.1000-582X.2009.08.002
Abstract:Based on the analysis of flowing combustion, gasification reaction, and lumped parameter, a threeregion model is established to predict the temperature and gas components of Texaco coal gasifier. Using mass balance and energy balance equations to each zone, the model takes account of gas solid two phase flow, coal pyrolysis, radiation heat transfer, and heterogeneous and homogeneous kinetic chemical reactions. Based on the model, a program is developed for dynamic and static simulation. After parameterization and simulation analysis, some important trends and conclusions are attained. Because the model can accurately predict the temperature and gas components in jet region, it has widespread engineering application value.
WANG Chengshan , XIAO Xingguo , WANG Wenzhong
2009, 32(8):869-875. DOI: 10.11835/j.issn.1000-582X.2009.08.003
Abstract:System simulation for COREX process not only gives guidance for its development, but also produces a theoretical basis for the design of its computer control system. A composite model for computational analysis on COREX process of ironmaking has been developed. The model combines a set of common material and heat balance equations, chemical equilibrium equations, and other considered correlations.These equations or correlations are coupled together through the material flows and energy flows between each two of all reactors in COREX process. All parameters are calculated based on one ton hot metal. The consumptions of ore and flux, the quantity of slag, and the composition of slag are calculated using the mass conservation for the element of Fe and the oxides such as CaO、MgO、SiO2、Al2O3、MnO and P2O5, etc. The gas volume and composition are calculated using the mass conservation for the elements of C and H and the chemical equilibrium of watergas reaction, etc. The O2 consumption is calculated using the conservation of the element O. The coal consumption is calculated by using of heat balance for the meltergasifier.
YU Jiangtao , LI Mingwei , CAO Yachao , CHENG Min , SHI Hang
2009, 32(8):876-881. DOI: 10.11835/j.issn.1000-582X.2009.08.004
Abstract:growth experiments of ammonium dihydrogen phosphate (ADP) pointseed crystal were employed. And it is shown that the growth rate of (100) surface increases linearly with the increase of supersaturation under the conditions of 0.005 kT/ωs~ 0.03 kT/ωs for phase transition drive force and 20~40 ℃ for the growth temperature. The growth rate of (100) surface increases exponentially with the rise of temperature when drive force is constant. The kinetics mechanism of crystal surface growth is in agreement with the screw dislocation growth under the condition of bulk diffusion transfer mechanism. There is death zone resulting from thermodynamic factors in crystal growth when the drive force is less than the critical value. The growth rate of (100) surface increases nonlinearly with increasing supersaturation when drive force is within 0.05 kT/ωs~0.11 kT/ωs. The crystal growth is dominated by the 2Dnucleation mechanism with the existence of other growth mechanisms.
LIAO Xiaofeng , JIN Yuanzhi , ZHANG Yanke , ZHOU Qing
2009, 32(8):882-886. DOI: 10.11835/j.issn.1000-582X.2009.08.005
Abstract:A novel robust blind watermarking algorithm in DCT domain was proposed. The DCT coefficients are arranged in a specific way, and then the watermark is embedded based on oddeven difference for optimal embedding. This algorithm works in a new pattern other than blockdivision and search of the DCT coefficients in the middle frequencies in the traditional pattern, which can overcome the problem in searching suitable coefficients in the middle frequencies for watermark embedding and the small embedding capacity. Experimental results show that the algorithm is simple and good at perceptual transparency as well as robustness against noise and JPEG compression.
ZENG Jianbang , LI Longjian , CUI Wenzhi , CHEN Qinghua , WANG Feng
2009, 32(8):887-891. DOI: 10.11835/j.issn.1000-582X.2009.08.006
Abstract:Lattice Boltzmann method is used to simulate the methanol steam reforming process in a micro channel. Lattice evolution model with dualrate kinetic parallel reaction mechanism is established. The impacts of boundary temperature, inlet velocity on reaction outlet parameters, such as methanol conversion rate, outlet concentrations of hydrogen and carbon monoxide and maximum temperature difference, are studied. It is found that under a certain boundary temperature and inlet velocity, when the methanol molar ratio, boundary temperature and inlet velocity are 1.3, 523 K and 0.1 m/s respectively, the methanol conversion ratio can reach the highest value of 94.36%, together with the concentrations of hydrogen and carbon monoxide of 0.098 9 and 0.009 5% respectively. With the increase of boundary temperature and decrease of inlet velocity, the concentration of CO will increase.
LIN Tengjiao , LIAO Yongjun , LI Runfang , LIU Wen
2009, 32(8):892-896. DOI: 10.11835/j.issn.1000-582X.2009.08.007
Abstract:Considering the internal dynamic excitation produced by stiffness excitation, error excitation and mesh impact excitation, a dynamic finite element model of transmission system and structure system of gearbox is established. The normal mode and the dynamic responses of gearbox under the internal dynamic excitation are calculated by using the numerical simulation software ANSYS. Based on the result of dynamic responses, the boundary excitation condition is determined, and then the acoustic boundary element model is built. With the software of SYSNOISE, the surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The test of airborne noise is carried out. The computational results obtained are in a good agreement with the data of experimental test.
LIU Zhenjun , HU Jianjun , LI Guanghui , QIN Datong
2009, 32(8):897-903. DOI: 10.11835/j.issn.1000-582X.2009.08.008
Abstract:The advantages and disadvantages of present methods for shift schedule analysis of automatic transmission vehicle are analyzed. An optimum shift schedule method based on fuzzy neural network is proposed. The structure and algorithm with Takagi-Sugeno mode is studied. Fuzzy logic rules with two parameters and membership functions for shift schedule are established according to the skilled driver’s experience and expert’s knowledge. The membership functions and fuzzy logic rules are modified through train mechanism of artificial neural network based on experiment sample. The fuzzy neural network is trained and simulated. The simulation results indicate that this shift schedule method based on fuzzy neural network of Takagi-Sugeno model is feasible and correct.
2009, 32(8):904-909. DOI: 10.11835/j.issn.1000-582X.2009.08.009
Abstract:On account of the inexpressibly complex features of the urban space network, the axial model analysis mechanism in space syntax is used to explore the inherent logic regularities of the urban space networkconfiguration. Through both quantitative and graphic qualitative descriptions of topological relations of urban space network and its functional attributes, the bottomtotop inherent regularities and toptobottom mandatory planning is further presented as well. With these, a platform is built for the studies of the unity relation of urban space network, thus the design schemes of urban designers can input positive, active and highly effective impetus with following with the systematicness and selforganization of urban space development.
YANG Jian , LIU Qingcai , ZHENG Huimin , DONG Lingyan , XIA Kefei
2009, 32(8):910-914. DOI: 10.11835/j.issn.1000-582X.2009.08.010
Abstract:The oxidation of calcium sulfite directly affect the final rate of flue gas desulfurization, but the study on the expression of oxidation rate is still in a dispute. Ferrouscatalytic oxidation kinetics of calcium sulfite has been studied with experiments in the oxidation stimulant which is 1.2 m diameter and 1.2 m height. The reaction order of bisulfite ion, ferrous ion and dissolved oxygen were 1, 0.5 and 0 respectively, and the activation energy was 54.52 kJ·mol-1. A kinetic model for the oxidation process of flue gas desulfurization technology has also been set up based on the Fick law and double film theory. Reaction order of bisulfite ion, ferrous ion and dissolved oxygen were 1, 0.5 and 0, and the activation energy was 53.85 kJ·mol-1. With the results of experiment and model, the precision of the model is high with relative error of 1.22%.
ZHU Xun , DANG Nan , TIAN Xin , LIAO Qiang , WANG Yongzhong , LI Jun , SHI Yong , DING Yudong
2009, 32(8):915-919. DOI: 10.11835/j.issn.1000-582X.2009.08.011
Abstract:In a platetype bioreactor for biofilm development, the experiments for the growth characteristic of highefficiency hydrogenproduction photosynthetic bacterial biofilm was undertaken under three different monochromatic light source with light wavelengths varied from 420 nm to 590 nm. The effect of light wavelength on the parameters of Rhodoseudomonas palustris biofilm is discussed, such as the surface coverage rate, thickness, dry weight, and density. The light wavelength has significant influences on the growth rate and structure of biofilm. Increased wavelength results in a higher surface coverage rate. While the dry weight of biofilm keeps almost constant at the same period. After 4 days, the thickness of biofilm decreases with the increase in light wavelength while longer light wavelength leads to higher density of biofilm, which results from the cell division and production of EPS by short light wave.
LI Zhengying , LI Zhengliang
2009, 32(8):920-924. DOI: 10.11835/j.issn.1000-582X.2009.08.012
Abstract:Based on a spatial nonstationary model of seismic ground motion, the seismic acceleration time history are simulated by the wave superposition method. And then taking CaiYuanBa arch bridge in Chongqing as original model , this paper utilizes timehistory analysis method to analyze the seismic response characteristic of this type of longspan arch bridge by support consistent or multisupport seismic excitation .The numerical results indicate that the spatial variation of seismic ground motion have significant effect on the response of the arch bridge. Thrust of arch rib and vertical displacement, internal force of arch crown are increased greatly, but most internal forces of stiffener support are reduced.
ZHANG Chengchang , LI Changyong , KANG Xiaoping , CHEN Yuping
2009, 32(8):925-930. DOI: 10.11835/j.issn.1000-582X.2009.08.013
Abstract:The surfaces of the Planar Spiral Antennas and Conical Spiral Antennas are analyzed with planar triangle. The surface currents of the antennas are solved by using the Method of Moment (MoM) based on the RWG basis function. The input impedance, directivity, gain, radiated power and radiation field of the antenna can be found. The results indicate that, in very wide frequency band, the value of the input impedance equals to the theoretical value of Self-Compensated antennas (in agreement with Babinet-booker' principle), which is,188.5 ohm , the half of the wave impedance of free space, while the directivity, gain and radiated power are stable within the frequency band. When the antenna is driven by the signal of derivative Gaussian pulse, the radiating electric field waveform is obtained by the Fourier transform. When the spiral antenna is used as the pulse radiation antenna, the waveform of the radiation electric field shows the characteristics of the Gaussian quadratic differential.
ZHANG Li , LU Liwei , LIU Tianmo , LI Nan , SUN Chaoyong
2009, 32(8):931-936. DOI: 10.11835/j.issn.1000-582X.2009.08.014
Abstract:A new dualdirectional extrusion (DDE) technique is applied on AZ31 Mg alloy at different extrusion ratios and temperatures by an extruder whose maximum load is 100t. In this experiment, the grain size is significantly reduced from 400 μm ascast to 6 μm asextruded when the extrusion ratio is 4.5; while at elevated extrusion ratio of 10.125, the grain size is reduced to 3 μm. The microhardness, compressive ratio, elongation and yield strength are all improved a lot and decreased with the increase of extrusion temperatures (except 250 ℃).
2009, 32(8):937-942. DOI: 10.11835/j.issn.1000-582X.2009.08.015
Abstract:In order to evaluate the air distribution using CFD method scientifically, former evaluation indexes of air distribution are modified by quality weighting method. A numerical simulation model is developed for the calculation and verified by experiment. Indoor air distribution in four operating modes of ceiling mounted indoor unit is simulated with the model. Comparing the existing evaluation indexes and the modified ones, it is found that significant differences in the indexes result in different evaluation results and the modified ones are more reasonable and appropriate.
ZHAO Liangju , YANG Nanqi , WU Duo , SU Chenggong
2009, 32(8):943-949. DOI: 10.11835/j.issn.1000-582X.2009.08.016
Abstract:The flow mechanism of flowing over two circular cylinders in tandem arrangements is numerically investigated. First, the unsteady incompressible NavierStokes equation is solved using twodimensional large eddy simulation (LES) model in order to capture the flow instantaneous source data. Then both the FWH equation and its integral solutions based on Lighthill’s acoustic analogy are employed to compute the noise generated by fluid flow. Different flow velocity, circle cylinder diameter and spacing ratios are compared. The result shows that the SPL augments with the increase of flow velocity or circle cylinder diameter. The frequency of vortices shedding is raised with the increase of flow velocity. Different spacing ratios impact the vortices shedding at a certain extent, and as a result impact the acoustic noise. There is the largest SPL near the critical spacing and the direction of acoustic fields is obvious.
YAN Bo , LIU Cheng , LIU Jun , ZHAO Li
2009, 32(8):950-954. DOI: 10.11835/j.issn.1000-582X.2009.08.017
Abstract:Using the finite element method, the stress intensity factor (SIF) of the cracked penal repaired with a multilayered piezoelectric patch is studied. The effects of the parameters, including the voltage applied on the patch, the piezoelectric patch layer and the geometric size of the patch, on the SIF are numerically investigated, based on which the repair efficiencies in different repair parameters are assessed. Based on the results of the numerical models, that the SIF of the cracked panel repaired with a piezoelectric patch is attenuated greatly. Better repair efficiency is obtained with the increase of voltage, but too higher voltage may be unbeneficial. It is beneficial to use more layers in the piezoelectric patch as the thickness of the patch is fixed. The SIF of the repaired cracked panel decreases with the increase of the size of the patch, however, too large patch may not be helpful to elevate the repair efficiency.
2009, 32(8):955-959. DOI: 10.11835/j.issn.1000-582X.2009.08.018
Abstract:Frequency offset and timing error seriously influence the performance of the Orthogonal Frequency Division Multiplexing (OFDM) system. Based on the special symmetric pilot sequence and known frequency synchronization methods, an improved timing and frequency synchronization method is presented. By using one OFDM pilot inserted in both time and frequency areas, the method can simultaneously implement timing and frequency synchronization, which can increase the efficiency of wireless data transmission. Simulation and analysis shows, with this special well-correlated symmetric pilot to implement accurate timing synchronization, the frequency offset estimation performance is greatly improved compared with S&C algorithm.
CAI Congzhong , WEN Yufeng , ZHU Xingjian , PEI Junfang , XIAO Tingting
2009, 32(8):960-964. DOI: 10.11835/j.issn.1000-582X.2009.08.019
Abstract:The support vector regression (SVR) method combined with particle swarm optimization (PSO) is proposed to establish a model for predicting the thermal conductivity of timber in transverse directions (radial direction and tangential direction) based on the measuring database of thermal conductivity under different influential factors, including its density, moisture content and specific gravity. Comparing the prediction results of SVR method with those from analogism (ANA) model and BP neural network (BPNN) model, it is shown that the prediction precision is higher for SVR method by applying identical training and test samples and increase of training samples could improve the generalization ability. With the validation test by leave-one-out cross validation (LOOCV) test, maximal absolute percentage error (MPE), mean absolute error (MAE) and mean absolute percentage error(MAPE), are the smallest for the prediction of SVR method. It is suggested that SVR is an effective and powerful tool for predicting thermal conductivity of timber.
TANG Ju , ZHU Liming , GONG Ningtao , ZHANG Xiaoxing , WEI Gang
2009, 32(8):965-970. DOI: 10.11835/j.issn.1000-582X.2009.08.020
Abstract:Four typical physical models for the internal insulation defects of 110kV cable joint are designed, while the test platform for Partial Discharges (PD) research on cable joint is constructed. A large number of PD data under different models are obtained by inner broadband ring sensor. The statistical analysis on the PD pattern indicates that there are significant differences between four PD forms on the statistical characteristics such as the phase distribution, skewness, kurtosis and degree of asymmetry, which can be used as effective features to reflect different characteristics of PD. Surface discharge and conductive particles may cause more serious damage to the insulation performance of cable joint, so high precaution should be paid on site operation.
WANG Zhiyuan , TONG Mingwei , YUAN Rubing
2009, 32(8):971-974. DOI: 10.11835/j.issn.1000-582X.2009.08.021
Abstract:Taking compressed air as the working medium, the performances of energy separation and temperature distribution in various kinds of vortex tubes are experimentally studied. Temperature distribution and refrigerating effect curve in vortex tubes are attained. The results show that the refrigerating effect of vortex tube with four nozzles is better than the other three kinds of vortex tube under the condition of ordinary temperature and 0.7 MPa pressure, and the refrigerating effect of vortex tube with six nozzles is worst in the four kinds of vortex tube. The refrigerating effect of nozzle with Achimid curve is best compared with other kinds of curves. The experiment shows that there is a boundary between cold and hot airflow at 0.7R of the tube, where cold airflow is inside the boundary and hot airflow is outside the boundary.
CHEN Xiaoqiang , LIU Jingcheng
2009, 32(8):975-978. DOI: 10.11835/j.issn.1000-582X.2009.08.022
Abstract:For the transmission pressure 27.5 kV of the railroad AC contact network, and the nonparallel (on earth) arbitrary plane for the wire wearing surface, the optic fiber was used to isolate the high voltage and to transmit the measurement signal. A remote gratingtype adaptive automatic machinery transducer was used to detect the AC contact network wire wearing surface with about seven meters from the ground. Based on this method, a system was designed and calibrated, achieving measurement of wire rubbing with highvoltage. The actual measurements indicate that the method and the system satisfy the demand of the measurement of contact network wire wearing. The method is significant to the geometric sense measurement of the high voltage charged body.
QU Zhongtang , YUAN Ruo , CHAI Yaqin , YE Guangrong
2009, 32(8):979-982. DOI: 10.11835/j.issn.1000-582X.2009.08.023
Abstract:A granisetron hydrochloride selective electrode is prepared based on granisetrontetraphenylboron as a carrier . Orthogonal methodology is adapted for studying the impacts of active substance content and Plasticizer on response performance of PVC Membrane Electrode. The option of Granisetron hydrochloride Sodium Tetraphenylboron IonAssociation Compounds(4.8% in membrane) as active substance and Dinoctyl phthalate(DOP) as Plasticizer is the best scheme. A fast nearNernstian response is shown for granisetron of 5.0×10-2~1.0×10-5 mol·L-1 with the slope of 58.7 mV/decade. The detection limit is 8.0×10-6 mol·L-1 and the electrode can be used for potentiometric determination of granisetron hydrochloride tablets directly. The recovery range is 99%~102% which is in agreement with those determined by the method in the Pharmacopoeia.
JIANG Libiao , MA Yue , YU Jianwei , LIU Yonghua
2009, 32(8):983-986. DOI: 10.11835/j.issn.1000-582X.2009.08.024
Abstract:Anomaly detection method was used for calibration data concentration significantly different from other data objects. In this paper, the multiphase clustering aimed at resolving the import of noise data and the lack of the attributive sample, and changing the traditional passive learning of bayes for active learning ways to structure the superior performance classifier. In the preprocessing stage, a clustering algorithm based on density is introduced to handle noise data. And the output of the densitybased clustering algorithm can be used as the input of Kmeans, which responsible for handling the training samples with absent values. At classification time, we introduce adaboost algorithm into naive bayes to generate a more effective classifier.