Volume 32,Issue 8,2009 Table of Contents

1 Design of subretinal artificial chip based on standard CMOS technology

PENG Chenglin , XIA Lu , HOU Wensheng , WANG Xing , ZHENG Xiaolin , YIN Zhengqin

2009, 32(8):859-863. DOI: 10.11835/j.issn.1000-582X.2009.08.001

[Abstract](2086) [HTML](0) [PDF 5.45 M](386)

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.

2 Establishment and analysis of dynamic mathematical model for coal gasifier

YANG Chen , KONG Defeng

2009, 32(8):864-868. DOI: 10.11835/j.issn.1000-582X.2009.08.002

[Abstract](2125) [HTML](0) [PDF 3.77 M](966)

Abstract:
Based on the analysis of flowing combustion, gasification reaction, and lumped parameter, a threeregion 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.

3 System simulation for COREX process: model descriptions

WANG Chengshan , XIAO Xingguo , WANG Wenzhong

2009, 32(8):869-875. DOI: 10.11835/j.issn.1000-582X.2009.08.003

[Abstract](1947) [HTML](0) [PDF 5.29 M](369)

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、SiO2、Al2O3、MnO and P2O5, etc. The gas volume and composition are calculated using the mass conservation for the elements of C and H and the chemical equilibrium of watergas reaction, etc. The O2 consumption is calculated using the conservation of the element O. The coal consumption is calculated by using of heat balance for the meltergasifier.

4 Growth of ADP pointseed crystal (100) surface

YU Jiangtao , LI Mingwei , CAO Yachao , CHENG Min , SHI Hang

2009, 32(8):876-881. DOI: 10.11835/j.issn.1000-582X.2009.08.004

[Abstract](2166) [HTML](0) [PDF 4.70 M](368)

Abstract:
growth experiments of ammonium dihydrogen phosphate (ADP) pointseed crystal were employed. And it is shown that the growth rate of (100) surface increases linearly with the increase of supersaturation 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 supersaturation when drive force is within 0.05 kT/ωs~0.11 kT/ωs. The crystal growth is dominated by the 2Dnucleation mechanism with the existence of other growth mechanisms.

5 Watermarking algorithm based on statistical property

LIAO Xiaofeng , JIN Yuanzhi , ZHANG Yanke , ZHOU Qing

2009, 32(8):882-886. DOI: 10.11835/j.issn.1000-582X.2009.08.005

[Abstract](2099) [HTML](0) [PDF 4.54 M](1063)

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 oddeven difference for optimal embedding. This algorithm works in a new pattern other than blockdivision 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.

6 Simulation of methanol steam reforming in micro channel with lattice Boltzmann method

ZENG Jianbang , LI Longjian , CUI Wenzhi , CHEN Qinghua , WANG Feng

2009, 32(8):887-891. DOI: 10.11835/j.issn.1000-582X.2009.08.006

[Abstract](2683) [HTML](0) [PDF 3.81 M](1217)

Abstract:
Lattice Boltzmann method is used to simulate the methanol steam reforming process in a micro channel. Lattice evolution model with dualrate 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.

7 Numerical simulation of dynamic response and radiation noise of gearbox

LIN Tengjiao , LIAO Yongjun , LI Runfang , LIU Wen

2009, 32(8):892-896. DOI: 10.11835/j.issn.1000-582X.2009.08.007

[Abstract](1897) [HTML](0) [PDF 4.74 M](1258)

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.

8 Analysis of shift schedule for the automatic transmission vehicle based on fuzzy neural network

LIU Zhenjun , HU Jianjun , LI Guanghui , QIN Datong

2009, 32(8):897-903. DOI: 10.11835/j.issn.1000-582X.2009.08.008

[Abstract](2353) [HTML](0) [PDF 6.36 M](1257)

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.

9 Analysis on axial model of the urban space system

ZENG Xudong , JIANG Lili

2009, 32(8):904-909. DOI: 10.11835/j.issn.1000-582X.2009.08.009

[Abstract](1770) [HTML](0) [PDF 5.58 M](1866)

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 networkconfiguration. Through both quantitative and graphic qualitative descriptions of topological relations of urban space network and its functional attributes, the bottomtotop inherent regularities and toptobottom 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 selforganization of urban space development.

10 Kinetics analysis of oxidation process of calcium sulfite in flue gas desulfurization technology

YANG Jian , LIU Qingcai , ZHENG Huimin , DONG Lingyan , XIA Kefei

2009, 32(8):910-914. DOI: 10.11835/j.issn.1000-582X.2009.08.010

[Abstract](1650) [HTML](0) [PDF 5.40 M](1140)

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. Ferrouscatalytic 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%.

11 Characteristics of the effect of light wavelength on the growth of photosynthetic bacterial biofilm

ZHU Xun , DANG Nan , TIAN Xin , LIAO Qiang , WANG Yongzhong , LI Jun , SHI Yong , DING Yudong

2009, 32(8):915-919. DOI: 10.11835/j.issn.1000-582X.2009.08.011

[Abstract](2600) [HTML](0) [PDF 5.21 M](1476)

Abstract:
In a platetype bioreactor for biofilm development, the experiments for the growth characteristic of highefficiency hydrogenproduction 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.

12 Seismic response of longspan arch bridge under spatially variable seismic exicitation

LI Zhengying , LI Zhengliang

2009, 32(8):920-924. DOI: 10.11835/j.issn.1000-582X.2009.08.012

[Abstract](2089) [HTML](0) [PDF 6.59 M](1405)

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 timehistory analysis method to analyze the seismic response characteristic of this type of longspan arch bridge by support consistent or multisupport 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.

13 Numerical analysis on the performance of spiral antennas

ZHANG Chengchang , LI Changyong , KANG Xiaoping , CHEN Yuping

2009, 32(8):925-930. DOI: 10.11835/j.issn.1000-582X.2009.08.013

[Abstract](1826) [HTML](0) [PDF 6.34 M](1173)

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.

14 Microstructure and mechanical properties of AZ31 Mg alloy after dualdirectional extrusion

ZHANG Li , LU Liwei , LIU Tianmo , LI Nan , SUN Chaoyong

2009, 32(8):931-936. DOI: 10.11835/j.issn.1000-582X.2009.08.014

[Abstract](2088) [HTML](0) [PDF 8.40 M](1531)

Abstract:
A new dualdirectional 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 ascast to 6 μm asextruded when the extrusion ratio is 4.5; while at elevated extrusion ratio of 10.125, the grain size is reduced to 3 μm. The microhardness, compressive ratio, elongation and yield strength are all improved a lot and decreased with the increase of extrusion temperatures (except 250 ℃).

15 Modification for evaluation indexes of air distribution

LIAN Zhiwei , QI Dahai

2009, 32(8):937-942. DOI: 10.11835/j.issn.1000-582X.2009.08.015

[Abstract](1919) [HTML](0) [PDF 5.84 M](445)

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.

16 Aeroacoustics numerical simulation of flow past towdimensional two circular cylinders in Tandem arrangements

ZHAO Liangju , YANG Nanqi , WU Duo , SU Chenggong

2009, 32(8):943-949. DOI: 10.11835/j.issn.1000-582X.2009.08.016

[Abstract](1742) [HTML](0) [PDF 9.21 M](404)

Abstract:
The flow mechanism of flowing over two circular cylinders in tandem arrangements is numerically investigated. First, the unsteady incompressible NavierStokes equation is solved using twodimensional large eddy simulation (LES) model in order to capture the flow instantaneous source data. Then both the FWH 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.

17 Repair efficiency of cracked panel repaired by a piezoelectric patch

YAN Bo , LIU Cheng , LIU Jun , ZHAO Li

2009, 32(8):950-954. DOI: 10.11835/j.issn.1000-582X.2009.08.017

[Abstract](2072) [HTML](0) [PDF 4.13 M](325)

Abstract:
Using the finite element method, the stress intensity factor (SIF) of the cracked penal repaired with a multilayered 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.

18 Time and frequency synchronization algorithm using training sequence for OFDM systems

TAN Xiaoheng , WANG Meimei

2009, 32(8):955-959. DOI: 10.11835/j.issn.1000-582X.2009.08.018

[Abstract](1946) [HTML](0) [PDF 3.86 M](393)

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.

19 Wood thermal conductivity prediction by using support vector regression

CAI Congzhong , WEN Yufeng , ZHU Xingjian , PEI Junfang , XIAO Tingting

2009, 32(8):960-964. DOI: 10.11835/j.issn.1000-582X.2009.08.019

[Abstract](2443) [HTML](0) [PDF 3.79 M](349)

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.

20 Statistical characteristics analysis of partial discharge in highvoltage cable joint

TANG Ju , ZHU Liming , GONG Ningtao , ZHANG Xiaoxing , WEI Gang

2009, 32(8):965-970. DOI: 10.11835/j.issn.1000-582X.2009.08.020

[Abstract](2080) [HTML](0) [PDF 5.09 M](643)

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.

21 Experimental Study on Channel Characteristic and Refrigerating Effect in Vortex Tubes

WANG Zhiyuan , TONG Mingwei , YUAN Rubing

2009, 32(8):971-974. DOI: 10.11835/j.issn.1000-582X.2009.08.021

[Abstract](2333) [HTML](0) [PDF 13.39 M](509)

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 0.7R of the tube, where cold airflow is inside the boundary and hot airflow is outside the boundary.

22 Online wine wearing detection device for AC contact network

CHEN Xiaoqiang , LIU Jingcheng

2009, 32(8):975-978. DOI: 10.11835/j.issn.1000-582X.2009.08.022

[Abstract](2491) [HTML](0) [PDF 3.11 M](361)

Abstract:
For the transmission pressure 27.5 kV of the railroad AC contact network, and the nonparallel (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 gratingtype 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 highvoltage. 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.

23 Preparation and content determination of ionselective electrode granisetron hydrochloride with high selective 5HT3 receptor antagonist

QU Zhongtang  , YUAN Ruo , CHAI Yaqin , YE Guangrong

2009, 32(8):979-982. DOI: 10.11835/j.issn.1000-582X.2009.08.023

[Abstract](2348) [HTML](0) [PDF 3.05 M](348)

Abstract:
A granisetron hydrochloride selective electrode is prepared based on granisetrontetraphenylboron 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 IonAssociation Compounds(4.8% in membrane) as active substance and Dinoctyl phthalate(DOP) as Plasticizer is the best scheme. A fast nearNernstian 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.

24 Anomaly detection based on the multiphase clustering and naive bayes

JIANG Libiao , MA Yue , YU Jianwei , LIU Yonghua

2009, 32(8):983-986. DOI: 10.11835/j.issn.1000-582X.2009.08.024

[Abstract](2387) [HTML](0) [PDF 3.04 M](408)

Abstract:
Anomaly detection method was used for calibration data concentration significantly different from other data objects. In this paper, the multiphase 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 preprocessing stage, a clustering algorithm based on density is introduced to handle noise data. And the output of the densitybased clustering algorithm can be used as the input of Kmeans, 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.

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