Volume 32,Issue 9,2009 Table of Contents

1 Numerical analysis of noise radiation from motorcycle engine shell

YANG Cheng , ZHOU Ke , CHEN Xu , WU Xingrang , WANG Zhongfang , ZHOU Jinjia

2009, 32(9):987-991. DOI: 10.11835/j.issn.1000-582X.2009.09.001

[Abstract](2048) [HTML](0) [PDF 7.16 M](1029)

Abstract:
FEM/BEM (Finite Element Method/Boundary Element Method) mode analysis of the noise radiation from motorcycle engine shell is conducted. The natural frequency is compared between FEM/BEM analysis and experimental analysis. The FEM/BEM results are agreed with the experiment results, which proves that the finite element model is correct. The frequency response is analyzed and the structure’s noise radiation is simulated by means of FEM/BEM, in order to predict the noise radiation from the motorcycle engine shell and gain the sound field characteristic outside the structure. The calculation data is compared with the experiment data in different frequency bands. The result shows high accordance, which indicates that this method is effective.

2 Study on thermal performance of vessel type green roof

TANG Mingfang , ZHENG Kaili , YAN Yonghong , KE Sizheng

2009, 32(9):992-996. DOI: 10.11835/j.issn.1000-582X.2009.09.002

[Abstract](1993) [HTML](0) [PDF 4.78 M](1199)

Abstract:
The thermal parameter measurements was carried out for vessel type green roof and bare roof in the airconditioned indoor environment in summer 2008 in Xiamen, China. The results show that temperature difference between internal surface of green roof and indoor air is about 1.5 ℃, and the heat flow from green roof is about 5.0 W/m the additional equivalent thermal resistance of vessel type green is larger than 1.0 m2·K/W.

3 Design and fabrication of a novel resonator for resonant accelerometer

HE Gao fa , TANG Yi ke , ZHOU Chuan de , HE Xiao ping , WU Ying

2009, 32(9):997-1001. DOI: 10.11835/j.issn.1000-582X.2009.09.003

[Abstract](2274) [HTML](0) [PDF 5.45 M](1406)

Abstract:
A novel resonator for accelerometer with sensing and actuating combs was designed and fabricated based on microelectromechanical system (MEMS) process. Driving force and demand voltage of the resonator were analyzed by analytical method and FiniteElement Method (FEM). Sensing capacitance on resonance state and Qfactor under atmosphere was calculated by these two methods. The microfabrication process was planned and realized using MEMS (Microelectromechanical System) method. The testing results show the performance of the resonator is high; the natural frequency of the resonator is 54 523.5 Hz, which has the error of 13.6％ with the theorical value.

4 Study on NO2 gas sensing characteristics of Indoped ZnO thin films prepared by RF magnetron sputtering

FANG Liang , PENG Liping , YANG Xiaofei , HUANG Qiuliu , ZHOU Ke , WU Fang , LIU Gaobin , MA Yong

2009, 32(9):1002-1005. DOI: 10.11835/j.issn.1000-582X.2009.09.004

[Abstract](2667) [HTML](0) [PDF 4.06 M](1135)

Abstract:
Indoped ZnO thin films were prepared on glass substrate by RF magnetron sputtering. The result of XRD and AFM shows that the films are polycrystalline with high caxis orientation. The study of gas sensing reveals that the films are sensitive to NO2 and the best sensibility occurs at 273 ℃; the sensibility is concerned with the concentration of NO2 and the film thickness. The ZnO∶In films are more sensitive to the NO2 gas with higher concentration of NO2 and thinner films have a better sensitivity. Exposed to 2×10-5 NO2 at 273 ℃, the 90nm thick film has a sensibility of 16, indicating that ZnO∶In films can be used to measure NO2 with a low concentration.

5 Kolmogorov entropy analysis of surrounding rock system in the processing of unloading for deepburied tunnels

ZHAO Yu , LU Yiyu , KANG Yong

2009, 32(9):1006-1010. DOI: 10.11835/j.issn.1000-582X.2009.09.005

[Abstract](1849) [HTML](0) [PDF 5.01 M](1027)

Abstract:
Rock is a kind of physical nonlinear complicated medium, under deepburied condition the surrounding rock system deformation shows geometrical nonlinear characteristic, and the interaction between the two nonlinear mechanism makes the unloading of surrounding rock system evolving complexly. Based on the Lagrangian method and large deformation caculation method, both the doublenonlinearity and nonlinear dynamics character of deepburied tunnel surrounding rock system under unloading are studied. The numerical model results show that the Kolmogorov entropy has been extracted from the evolution data in the unloading process of surrounding rock system. The analysis indicates that the typical chaos character has been demonstrated in the process of unloading for deepburied tunnel surrounding system and the rock mass energy dissipation is analyzed at the stage of unloading.

6 Numerical simulation of NO and N2O emission in fluidized bed reactor

ZHOU Jiaping , TANG Qiang , ZHANG Li , HOU Shifeng

2009, 32(9):1011-1015. DOI: 10.11835/j.issn.1000-582X.2009.09.006

[Abstract](2059) [HTML](0) [PDF 3.34 M](1151)

Abstract:
Both NO and N2O emission in fluidized bed reactor are studied by numerical simulation. The effects of excess air ratio, coal composition and cocombustion of coal and biomass are researched. The results show that NO and N2O are the main products of the NOx in the fluidized bed reactor combustion, and the emission of NO and N2O increases with the excess air ratio increasing. The NOx production has strong relationship with coal composition. The nitrogen content of the coal plays an important role in the production of NO and N2O, as well as oxygen to nitrogen mass ratio and hydrogen to nitrogen mass ratio. In the cocombustion process of coal and biomass, carboxyl group have remarkable effect on HCN production, which reduces the content of NO and NO2. The cocombustion of coal and biomass can reduce the emission of NO and N2O.

7 Analysis of shifting control for dry dual clutch system

QIN Datong , ZHAO Yusheng , HU Jianjun , YE Ming

2009, 32(9):1016-1023. DOI: 10.11835/j.issn.1000-582X.2009.09.007

[Abstract](2029) [HTML](0) [PDF 6.54 M](1470)

Abstract:
Aiming at the dry Dual Clutch Transmission (DCT) system, the motordriven dry dual clutch actuator is studied; the characteristic of distortionload for diaphragm spring and the dynamic transient process of the clutch are analyzed. The mathematical model is established for the system using fuzzy control and PI (Proportion Integration) control, and the simulation is carried out for the DCT shifting process. Simulation results indicate that the motordriven dry dual clutch system can meet the need of the shifting process control requirements and guarantee the high performance of DCT system.

8 Automatic generation technology of the batch arrivals poduction rollingplan in multivarieties and smallbatch environment

WANG Shilong , YI Lili , REN Hengbin , CAI Bin

2009, 32(9):1024-1027. DOI: 10.11835/j.issn.1000-582X.2009.09.008

[Abstract](2519) [HTML](0) [PDF 3.91 M](1939)

Abstract:
Aiming at the characteristics of batch arrivals production in multivarieties and smallbatch environment, the processing components are classified into keyimportant and unkeyimportmant parts by their usage ratio. According to the principle of Knowledge Engineering, the keyimportant parts production rolling plan is generated by process metaknowledge of keyimportant parts. Unkeyimportant parts production plan is generated by ‘ABC Classification Scheduling Method’. In this way, the rolling plan problem in multivarieties and smallbatch production can be effectively solved.

9 Strength analysis for special bolt of largescale hanger system

TANG Qian , PEI Linqing , LU Bo

2009, 32(9):1028-1031. DOI: 10.11835/j.issn.1000-582X.2009.09.009

[Abstract](2313) [HTML](0) [PDF 3.53 M](1351)

Abstract:
By establishing the dynamic model and adopting the finite element method, the special bolt’s stress distribution and the contact areas between different components of the system are obtained. According to the analysis result, the bolt’s strength meets the operating requirement, bolt pretightening force has a great influence to the bolt strength, and gravity loads of cylinder cannot produce considerable changes of bolts, however, the phenomenon of deviation load is serious. The bolts experiment based on group of bolts is conducted to show degree of deformation. The experiment results are agreed well with the analysis results.

10 Thermal process model identification based on radial basisfunction neural networks

LI Panfeng , YANG Chen

2009, 32(9):1032-1036. DOI: 10.11835/j.issn.1000-582X.2009.09.010

[Abstract](1605) [HTML](0) [PDF 3.75 M](426)

Abstract:
In order to accurately reflect the dynamic behavior and realize the whole optimal control of the thermal process, a novel modeling method of the RBFNN (Radial Basis Function Neural Networks) model is proposed to build nonlinear model. This method is based on entropy clustering and competitive learning algorithm, combined with nonlinear autoregressive moving average (NARMA) model to identify the RBFNN stucture, and the power vector is gotten by the least square algorithm. Two simulation experiments show that the proposed method of the identification based on NARMA model and RBFNN can accurately describe the nonlinearity of the process and has less hidden nodes.

11 Optimization design for hydraulicsupport of standing shield

WANG Zhongbin , ZHAO Lala , LI Shubin , NI Wenfeng

2009, 32(9):1037-1042. DOI: 10.11835/j.issn.1000-582X.2009.09.011

[Abstract](2501) [HTML](0) [PDF 4.50 M](430)

Abstract:
In order to improve the capabilities of managing the roof and enduring the load of the standing shield’s hydraulic support, the motion trace of the roof beam endpoint should be approximate twisted pair line, and its maximal horizontal swing value should be minimal. In this paper, the motion characteristics for the fourbar linkage of the hydraulic support were analyzed, and its mathematic model for optimization design was established. The length of each bar and the correspondent parameters were determined by genetic algorithm, when the motion trace of the roof beam endpoint was twisted pair line, and the maximal horizontal swing value e of the roof beam endpoint was minimal. The ZY35 hydraulic support was taken as an example to validate the optimization result. The ideal design parameters of the ZY35 hydraulic support can be obtained based on genetic algorithm, and its working status and support effect is stable and favorable.

12 Quantitative assessment method for the quality of anchors

CHEN Jiangong , LIU Haiyuan , ZHANG Yongxing

2009, 32(9):1043-1048. DOI: 10.11835/j.issn.1000-582X.2009.09.012

[Abstract](2136) [HTML](0) [PDF 4.72 M](428)

Abstract:
A method is developed to quantitatively assess the quality of anchors. An analytical model is combined with the wavelet analysis and artificial neural network is used to estimate the values of boltside stiffness coefficients for the anchor system. The samples of bolt’s anchorage system are fed into the artificial neural network for training. It’s a useable intelligent mean to assess the quality of bolt’s anchor system. The dynamic parameters of integrity bolt with different physical and mechanical parameters of surrounding rocks are acquired. A relationship curve between boltside stiffness and surrounding rock’s modulus of deformation is erected, and its quadratic fitting formula is acquired. The curve and the formula can be used as the assessment standards for the anchor quality. The anchor degree is used to judge the anchor quality. The quantitative assessment method is applied to the engineering field.

13 Highly linear wideband low noise amplifier based on GaAs pHEMT

TAN Xiaoheng , FU Yangdong , LIN Jie , HUANG Jian

2009, 32(9):1049-1053. DOI: 10.11835/j.issn.1000-582X.2009.09.013

[Abstract](1872) [HTML](0) [PDF 3.74 M](390)

Abstract:
For the disadvantages of the complementary metal oxide semiconductor (CMOS) technology under high frequency, a wideband low noise amplifier (WLNA) for wireless telecommunication systems is designed based on gallium arsenide pseudo high electron mobility transistor (GaAs pHEMT). Negative feedback is used to design the WLNA to obtain smooth gain, low input and output reflection coefficient. Simulations were conducted with Advanced Design System 2005 for the designed circuit. Simulation results show that, in the band of 0.3～2.2 GHz, the gain of this WLNA is below 12 dB and fluctuation of gain is under 3 dB, while for the noise figure being between 1.04 dB and 1.43 dB, the input and output reflection coefficients are both below -10 dB, and the group delay in the whole band is close to linearity and this WLNA is unconditionally stable. This WLNA can well meet actual demands.

14 Design of compatible processing and analyzing system for nuclear signals

REN Yong , WEI Biao , FENG Peng , TANG Yuelin , MI Deling

2009, 32(9):1054-1058. DOI: 10.11835/j.issn.1000-582X.2009.09.014

[Abstract](2489) [HTML](0) [PDF 4.15 M](395)

Abstract:
To online detect, store and process nuclear signals with multiple forms and multiple frequencies, a compatible processing and analyzing system for nuclear signals based on ultrahighspeed data acquisition card was constructed. When the source signal is at pulse form, the system records signal with the mode of timedigitalconverting. When source signal is at continuous form, the system records signal with the mode of analogdigitalconverting. The processing procedures and algorithms were designed for various signal forms. The results for nuclear random process such as correlation function and power spectrum were effectively obtained.

15 Classification of ultra high frequency partial discharge signalsin gas insulated switchgear based on complex wavelet transform

TANG Ju , XIE Yanbin , ZHOU Qian

2009, 32(9):1059-1064. DOI: 10.11835/j.issn.1000-582X.2009.09.015

[Abstract](2062) [HTML](0) [PDF 4.47 M](388)

Abstract:
In order to classify the ultrahighfrequency (UHF) partial discharge (PD) signals resulting from four types of insulation defects in gas insulated switchgear (GIS), the complex wavelet transform is applied to extract features of UHF PD signals. Five statistical parameters including mean, variance, kurtosis, skewness and energy are used to quantize the scaling coefficients of the complex wavelet transform and describe the feature subsets of UHF PD signals.A critical index J is defined to select features according to their classification performance. Using the J criterion, five optimal features are selected from sixty UHF PD features and taken as the input of radial basis function neural network. The classification results show that the information of real part and image part of complex wavelet coefficients indicates the characteristics of UHF PD singles and the recognition effect is pretty good. To use db4 complex wavelet can get the best classification performance.

16 Parameter design and simulation for animproved direct current side active power filter

HOU Shiying , JI Liming , SUO Lijuan , XU Xi

2009, 32(9):1065-1069. DOI: 10.11835/j.issn.1000-582X.2009.09.016

[Abstract](1796) [HTML](0) [PDF 4.54 M](406)

Abstract:
Considering the characteristics of the dc side series active power filter (APF) that the output voltage cannot be adjusted and the control circuit is complex , an improved singlephase dc series APF topology is proposed. The improvement of the new circuit topology and fundamental working principle are analyzed. Following the circuit power factor preregulator principle, the designing method for the main circuit parameters is given. The voltage ring and the current ring are designed by using the zeropole method. The main circuit power switch is controlled with the same frequencies, while the control circuit was simplified further. Compared with the paralleled APF, the main circuit of topology structure is simplified and the number of the active switches is reduced, which show low input current harmonics, high power factor, large voltage output adjustment range and low cost. The simulation results prove that the proposed topology is correct and reliable.

17 Pedestrian detection in infrared images

GUO Yongcai , HU Ruiguang , GAO Chao

2009, 32(9):1070-1073. DOI: 10.11835/j.issn.1000-582X.2009.09.017

[Abstract](1938) [HTML](0) [PDF 3.47 M](510)

Abstract:
A method based neural network for pedestrians detection in infrared images is presented. The background image is extracted adaptively with 3D median filtering and regions of interest (ROIs) are segmented out with the image difference method. The Fourier descriptors (FD) are employed as the shape feature of ROIs. A BP neural network is designed to recognize ROIs. The classifier is tested with a lot of samples with different types and different shapes. The experimental results show that the classifier has high true positive rate and low false positive rate, which can distinguish whether the ROIs are pedestrians or not effectively and efficiently.

18 Simulation study on COREX process system

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

2009, 32(9):1074-1079. DOI: 10.11835/j.issn.1000-582X.2009.09.018

[Abstract](1932) [HTML](0) [PDF 5.40 M](405)

Abstract:
System simulation is carried out based on the COREX process simulation model. The coal consumption increases with the increasing of the volatile content in coal. The control of volatile in coal is an important step for COREX’s ironmaking. The coal consumption decreases with the increasing of the oxidation degree of raw gas out of the meltergasifier. The energy utilization ratio of COREX process increases with the increasing of the oxidation degree or decreasing of the temperature of raw gas out of the meltergasifier. The maximum value of the energy utilization ratio is just over 50%. The temperature of raw gas should have a much higher value, compared with the temperature of reducing gas entering shaft furnace. The requirement of using much more kinds of coal and facilitating process operations is a key reason.

19 Selection of four hoisting points for largespan steel trusses based on strain energy method

YAO Gang , XIE Wei , JU Hu

2009, 32(9):1080-1085. DOI: 10.11835/j.issn.1000-582X.2009.09.019

[Abstract](2686) [HTML](0) [PDF 5.76 M](454)

Abstract:
The strain energy method is applied to hoisting point selection in structural hoisting, and the feasibility of this method is investigated. Based on the number of hoisting points, a structural analysis is carried out for each possible combination of hoisting points in the whole variable space of nodes. The strain energy corresponding to the each combination is obtained based on the member forces from the structural analysis. The combinations are sorted based on their magnitudes of strain energy, and the combination with the smallest strain energy is picked out. The structure needed to be hoisted is in a rational state when it has low strain energy. The combination with the smallest strain energy is treated as the best selection of hoisting points. Hoisting construction of a workshop in Chongqing was taken as an example and three construction conditions were considered. The commercial package ANSYS was used to conduct the structural analysis and obtain the strain energy. The best selections were verified by another software MADIS.

20 Experiment research on aseismatic capability of diagonally crossing reinforced coupling beams with the small ratio of span to depth fire safety design for ancient buildings

PI Tianxiang , FU jianping , BAI Shaoliang , YI bo , ZAN lin

2009, 32(9):1086-1092. DOI: 10.11835/j.issn.1000-582X.2009.09.020

[Abstract](1659) [HTML](0) [PDF 8.80 M](1326)

Abstract:
Low frequency cyclic loading experiments are carried out with six diagonally crossing reinforced coupling beams. The ratio of the span to depth is 1.0,1.5,2.0 and 2.5. The paper analyzes the behavior of crack development, failure mode, ductility, stiffness degeneration, hysteretic and energy dissipation of these specimens. The results show that the aseismatic behavior of properly reinforced diagonally cross reinforced coupling beams is better than conventionally reinforced coupling beams, and this kind coupling beam can get no less than 3.5 chord rotation ductility at the 0.20 ratio condition of shear to compression. For diagonally crossing reinforced coupling beams with the small ratio of span to depth, the mechanism of the main force transfer system is the main diagonal struttie model and stirrup truss model

21 Setting of fire scenarios in performancebased characteristic coefficient on the optimal quantity of concrete walls

WANG Houhua , LIU Xichen

2009, 32(9):1093-1097. DOI: 10.11835/j.issn.1000-582X.2009.09.021

[Abstract](2027) [HTML](0) [PDF 4.61 M](1397)

Abstract:
China has no fire protection regualtion about the ancient buildings, and the research on this issue is limited in China.This paper proposes some very important issues in the setting of fire scenarios for ancient buildings, especially the spread of fire. It discusses the criterion and process of fire scenario setting. The integrity procedure of fire scenario setting includes the fire position set, the fire development curve set and the fire spread analysis. Two ways of the fire spread are proposed.

22 Influence of masonryRC wall composite structures’ stiffness feature extraction and smallsample learning

SUN Yigang , PAN Zhihong

2009, 32(9):1098-1103. DOI: 10.11835/j.issn.1000-582X.2009.09.022

[Abstract](2283) [HTML](0) [PDF 4.72 M](1302)

Abstract:
According to the stress characteristics of masonryRC wall composite structures, the paper puts forward the calculation formula of the optimal number of RC walls under the action of earthquake. In the formula, the main influence factors of parameter of amount of RC walls are: the characteristic site period，the seismic fortification intensity，the elastic allowable deformation value, the stiffness characteristic coefficient of composite structures, the compensationcoefficient of the nonbearing walls on natural period of vibration,etc. According to the main influence factor, the stiffness characteristic coefficient λ, this study gets the value tables of parameter of amount of RC walls in the calculation formula of the optimal quantity of concrete wall under various antiearthquake grades，ground categories and design groups. A numerical example shows this method is simple and practical.It can be used for the initial design stage of this kind of composite structures in seismic regions.

23 Cost forecast model for power engineering based on based on back propagation neural networks

PENG Guangjin , YU Jihui , WEI Juntao , YANG Guang

2009, 32(9):1104-1110. DOI: 10.11835/j.issn.1000-582X.2009.09.023

[Abstract](2155) [HTML](0) [PDF 5.68 M](1120)

Abstract:
A novel power engineering cost forecast model was proposed by combining feature extraction and smallsample learning. The initial data was preprocessed with principal component analysis to remove the correlation among the original indexes and get the potential independent indexes. The new indexes acted as the input set to build a new forecast model based on least squares support vector machines. The results of this model were compared with the forecast results getting from artificial neural network. By comparing the forecast results with different principal components number, the optimal number was determined to achieve the desired forecast effect. The prediction results indicate that the method can extract the feature of initial data effectively and is good at smallsample learning . The expected forecasting results can be reached.

24 Fast algorithm for apparent resistivity calculation based on back propagation neural networks

XIE Pinfang , XIE Lintao , FU Zhihong , ZHANG Huaiqing

2009, 32(9):1111-1116. DOI: 10.11835/j.issn.1000-582X.2009.09.024

[Abstract](2654) [HTML](0) [PDF 4.91 M](1291)

Abstract:
To avoid the complex numerical calculation for the electromagnetic field and determine underground abnormality, a neural network based method is proposed. In consideration of turnoff transmitter current, the effect of a linear ramp turnoff current on transmitter is corrected. The characteristics of transient expression and the traditional calculation algorithm for apparent resistivity are analyzed, and a predigest structure of network is obtained based on the kernel expression. The threelayer back propagation(BP) neural network is trained by using sample data in homogeneous halfspace, and its number in hidden layer was determined. The method proposed is compared with two traditional calculation methods with simulation experiments. The result demonstrates that BP neural network has a high speed of processing data and is useful in explanation of the transient electromagnetic method.

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