Volume 31,Issue 12,2008 Table of Contents

1 Energy transmission process of combustion flame radiation in the tuyeres and raceways of blast furnaces

ZHANG Xinglan , OUYANG Qi , WEN Liangyin , BAI Chenguang

2008, 31(12):1337-1341. DOI: 10.11835/j.issn.1000-582X.2008.12.001

[Abstract](638) [HTML](0) [PDF 2.46 M](217)

Abstract:
We developed a process model of flame beam transmission using pulverized coal powder and coke combustion in a raceway. We employed a Monte Carlo computation method equation based on charge couple devrce(CCD) target heat flow distribution for radiation heat transfer. We explored the factors impacting radiation transmission. Based on these, a three dimensional reconstruction was analyzed at varying coke particle concentrations. This model provided an effective method to produce online monitoring of raceway working states.

2 A new method for calculating the vacancy formation energy of typicalstructure metals

ZHANG Xiyan , ZHAO Xinchun , JIA Chong , LIU Qing

2008, 31(12):1342-1345. DOI: 10.11835/j.issn.1000-582X.2008.12.002

[Abstract](990) [HTML](0) [PDF 1.65 M](3220)

Abstract:
Based on the model proposed by Tiwari and Patil, we improved the calculation method for surface energy, and calculated the vacancy formation energy for typical metals such as fcc, bcc and hcp metals. The calculated results and experimental values agree with each other when an energy modification coefficient is introduced. The energy modification coefficients of fcc, bcc and hcp metals are 1.292, 1.265 and 1.357, respectively. The proposed method can calculate and predict the vacancy formation energy of metals efficiently.

3 Brake disc thermal stress in material composite design

WANG Kai , LIU Changming , YANG Yong

2008, 31(12):1346-1350. DOI: 10.11835/j.issn.1000-582X.2008.12.003

[Abstract](705) [HTML](0) [PDF 2.20 M](1022)

Abstract:
The temperature distribution and thermal stress distribution of brake discs under emergency braking conditions were studied using the finite element method (FEM). The discs were of three types: those made of functionally graded SiCp/Zl104 composite materials, of uniform (20% volume) SiCp/Zl104 composite materials, and of compacted graphite iron, respectively. The rule of mixtures of dualphase material and the discretization of the material composition distribution were applied to estimate the material properties of functionally graded composite materials. The results show that the temperature and thermal stress of brake discs made of graded SiCp/Zl104 composite are the lowest among the three types studied, and the distribution of temperature and thermal stress of this brake disc type is more uniform than the others. Furthermore, brake discs made of functionally graded SiCp/Zl104 composite can reduce vehicle weight and increase wear resistance capacity. The results provide a theoretical foundation for fabricating brake discs made of graded SiCp/Al composite material.

4 Numerical analysis of material surface thaw depth under pulsed electron beam irradiation

XU Hongbin , HU Jianjun , CHEN Yuanfang , LI Dengbo

2008, 31(12):1351-1354. DOI: 10.11835/j.issn.1000-582X.2008.12.004

[Abstract](489) [HTML](0) [PDF 1.97 M](1045)

Abstract:
We developed a finite element method model. An equality heat source was used to thaw metal with an electron beam in numerical analysis. The temperature field was obtained after the metal thawed with electron beam by numerical analysis. The influence of the material thaw depth was analyzed at differing voltages, energy densities, and energy evenness. A thaw depth diagram was obtained where energy evenness is from 0.9 to 1.0, energy density is from 2 J/cm2 to 17 J/cm2, and voltage is from 25 kV to 50 kV. The change rule of material thaw depth was derived which provides a theoretical reference for fine mould machining with electron beams.

5 Gas sensing properties and mechanism of zinc stannate thick film gas sensors by doping noble metal catalysts

LIU Tianmo , GAN Haoyu , ZENG Wen

2008, 31(12):1355-1359. DOI: 10.11835/j.issn.1000-582X.2008.12.005

[Abstract](683) [HTML](0) [PDF 2.29 M](1076)

Abstract:
NanoZnSnO3 powders were prepared by the coprecipitation method, using ZnSO4·7H2O SnCl4·5H2O as the starting material. The ceramic powders were characterized by Xray diffraction and transmission electron microscopy. Pure and noble metaldoped ZnSnO3 thick film gas sensors were fabricated by an indirect heating process and the gas sensing properties were tested. The reason for the above improvement was analyzed on a gas sensing mechanism and the basis of morphology observation of these thick film sensors. The results show that the sensitivities of these thick sensors to combustible gases, such as C2H5OH and H2, are greatly improved. Gas sensitivities of thick sensors with doping metallic irons, including Ag+ and Pd2+ to hydrogen gas, are fifteen times greater than that of pure ZnSnO3 thick film sensors. The grain size is inhibited and more gas holes cover the surface by doping metallic irons, the key reason for the improved gassensing properties.

6 Hot rolling 35CrMo ultrathick wall seamless tubes

LI Yuanrui , HUI Zhiqiang , ZHANG Ying , ZHENG Shijian

2008, 31(12):1360-1364. DOI: 10.11835/j.issn.1000-582X.2008.12.006

[Abstract](614) [HTML](0) [PDF 1.69 M](1507)

Abstract:
35CrMo ultrathick wall seamless tubes were prepared after being hot rolled from a forged 305 mm×305 mm square blank using a Φ216 mm Pilger periodic mill. Tubes with 215 mm outer diameter, thickness of approximately 725 mm, and a 297 diameterwall ratio were obtained. Two sets of tubes were prepared after analyzing the reasons for high eccentricity and rolling parameters. The uniformity of rolling temperature, piercing quality and roll pass were considered during the procedure. The geometry size, microstructure and mechanical properties were measured. It is found that the tubes meet the technical requirements.

7 Using a genetic algorithm to optimize secondary cooling water distribution in slab casting

ZHENG Zhong , ZHAN Xianhui , LUO Xiaogang

2008, 31(12):1365-1370. DOI: 10.11835/j.issn.1000-582X.2008.12.007

[Abstract](467) [HTML](0) [PDF 2.74 M](813)

Abstract:
A genetic algorithm was used for coding the volume of cooling water in the secondary cooling zone based on the heat transfer model in realtime production. This was done to improve the dynamic control of the secondary cooling water in highefficiency continuous casting. The fitness function of multiobjective optimization in the algorithm is in accordance with the distribution of metallurgical criteria. The genetic algorithm was integrated with the metallurgical criteria and the heat transferring model to optimize the water distribution. These steps increase the distribution adaptability and improve its efficiency compared to the traditional optimization methods of solving multiobjective optimization and other nonlinear problems. Simulation using the process data of the No.2 slab caster in the Steelmaking Plant of Panzhihua Iron and Steel and onsite testing were carried out. The results show that the optimized distribution saves 2% of water than without optimization, while water distribution along the slab to the water gradually decreases in accordance with requirements for slab quality control.

8 A new codebookbased precoding scheme for multipleinput multipleoutput systems

HAO Donglai  , GE Jianhua

2008, 31(12):1371-1375. DOI: 10.11835/j.issn.1000-582X.2008.12.008

[Abstract](653) [HTML](0) [PDF 1.80 M](1200)

Abstract:
Focusing on the contradiction between overhead and performance in the codebookbased precoding scheme, a precoding method with a new codebook was proposed in which the concept of diversity was adopted in the codebook design. Performance of the codebook matrix was improved by the gain resulting from spatial diversity. Furthermore, a compensation unit for precoding was added in the scheme. The simulation results for the 4 by 4 antenna mode show that the proposed codebookbased precoding scheme for multipleinput multipleoutput system does not add any overhead and produces superior performance (approximately 1 dB to 2 dB) compared to traditional precoding schemes.

9 Frequency domain analysis and the application for extracting electroencephalogram signal characteristic waves

LIU Yuhong , XIE Zhengxiang , XIONG Xingliang , WANG Zhifang , LI Hong , WANG Ying

2008, 31(12):1376-1380. DOI: 10.11835/j.issn.1000-582X.2008.12.009

[Abstract](795) [HTML](0) [PDF 2.32 M](1884)

Abstract:
A new quantitative analysis method to describe the dynamic variation of electroencephalogram (EEG) signals was proposed. Based on the Fourier transformation, the method is called Fourier multiresolution analysis (FMRA). FMRA decomposes the frequency domain with a binary system and can resolve EEG signals into the basic rhythms of the four waves to study the dynamic characteristics of EEG signal rhythms. FMRA has clear physical meaning, and can obtain more information than wavelet multiresolution analysis does. FMRA can extract perfectly the rhythmic characteristics of EEG signals in the time and frequency domains.

10 A method to generate pseudorandom phases in transform domain communication system by chaos mapping

HE Shibiao , JI Ye , PAN Hui

2008, 31(12):1381-1385. DOI: 10.11835/j.issn.1000-582X.2008.12.010

[Abstract](656) [HTML](0) [PDF 2.41 M](1025)

Abstract:
The traditional method of generating pseudorandom phase vector through a linear feedback shift register (LFSR) and a preset combination of taps in transform domain communication system(TDCS) was studied. Based on the requirements of the pseudorandom phase vector in TDCS, a new method using chaos mapping to generate the pseudorandom phases in TDCS was proposed. This method generated binary quantization chaotic sequences by using chaos mapping with different initial values, and then creates a pseudorandom phase vector by using a phase mapper. Finally, the basis function was obtained. The implementation method of chaos mapping and the simulation results regarding the correlation performance for the basis function were discussed in detail. Compared with the basis functions generated by LFSR, the basis functions generated by chaos mapping have better correlation performance. Because many basis functions with small crosscorrelation coefficients can be generated by chaos mapping, this method is advantageous for multiple access applications.

11 Chaos expression of neuron dynamic simulation model with various stimulations

TIAN Xuelong , WEN Huizhong , XU Jia , Fan Zhixiang

2008, 31(12):1386-1390. DOI: 10.11835/j.issn.1000-582X.2008.12.011

[Abstract](590) [HTML](0) [PDF 2.20 M](1304)

Abstract:
Chaos controlbased disease control has become a new direction for medical research. Chaos control can improve the study of nervous system diseases. To explain the inherent characteristics of such treatment with neurophysiology, a neuron dynamic simulation model, based on the Chay model, was built with MATLAB/SIMULINK. Various stimulations were inserted to analyze the dynamic change of the neuron action potential and its chaos expression. The experimental results show that different internal and external stimulations to the nervous system have great influence on membrane potential and chaos expression, indicating the importance and feasibility of chaos control in disease control.

12 An artificial immunitybased predictive method for neural networks and its applications

YANG Jia , XU Qiang , CAO Changxiu

2008, 31(12):1391-1394. DOI: 10.11835/j.issn.1000-582X.2008.12.012

[Abstract](687) [HTML](0) [PDF 1.43 M](179)

Abstract:
A radial basis function (RBF) neural network learning algorithm based on immune recognition was proposed to improve the low forecast precision and the slow convergence speed of such networks. In the algorithm, artificial immunity was used to determine the center and width parameters of the Gauss basis function. The recognized data were regarded as antigens and the compression mapping of antigens were taken as antibodies, i.e., the centers of the hidden layer. The recursion least square algorithm (RLS) was employed to determine the output layer weights. The algorithm improved the convergence speed and precision of the RBF neural networks. The model was applied to the blast furnace of a large iron and steel company. The results show that the model has forecast precision far superior to existing models and requires less training time than they do.

13 A method for evolving the architecture and weights of neural networks via gene expression programming

WANG Yanchun , HE Dongjian , WANG Shouzhi

2008, 31(12):1395-1399. DOI: 10.11835/j.issn.1000-582X.2008.12.013

[Abstract](597) [HTML](0) [PDF 1.60 M](176)

Abstract:
An algorithm for automatic designation of the architecture and the weights of neural networks using gene expression programming (GEP) was presented. The fundamental ideas and procedures of the algorithm were discussed. The algorithm was improved to solve the problems of prematurity and lower variance rate. An application for neural networks designation was given. The experimental results indicate that the proposed GEP approach may evolve the architecture of neural network, and can obtain the weights more precisely. Compared to other conventional evolutional algorithms, GEP shows faster convergence.

14 Design and implementation of a collaborative monitoring system

DAI Qing , TIAN Feng , ZHOU Xingquan

2008, 31(12):1400-1404. DOI: 10.11835/j.issn.1000-582X.2008.12.014

[Abstract](537) [HTML](0) [PDF 1.65 M](180)

Abstract:
We designed a collaborative monitoring system based on JXTA. The system integrates P2P network technology with network management technology. We introduced the mechanism of JXTAs peer group, discussed the necessity of using a P2P network in a peer group application, presented the cooperative work scheme of P2P network, and emphasized the mechanism of peer group collaborative monitoring network when applying P2P network technology. The implementation method of the system was put forward by remotely monitoring the CISCO3640 port utilization ratio. The system features expansibility, usability, interoperability, high performance, decentralization, and robustness.

15 Design of a control system for auto loading and unloading of compressed natural gas bottles

TAN Chunlu , ZHONG Yuanchangab , LI Fei , DING Xuan

2008, 31(12):1405-1409. DOI: 10.11835/j.issn.1000-582X.2008.12.015

[Abstract](839) [HTML](0) [PDF 2.11 M](300)

Abstract:
The concept of centralized filling and separate bottle displacement was introduced to reduce the inconvenience of filling compressed natural gas(CNG) vehicles. By taking a programmable logic controller (PLC) as the smart control unit and stepper motors as drive units, a mobile threedimensional table was designed as a working platform. The stepper motor control algorithm was studied, and the system model for the CNG vehicles automatic loading and unloading was constructed. A new automatic loading and unloading system for CNG vehicle bottles was developed. Theoretical analysis and experimental results show that the system can complete the automatic loading and unloading task in 1 or 2 minutes, thereby improving CNG vehicle filling efficiency.

16 Numerical simulation of solidliquid flow of Yangtze River water in a semiannulus reentry tube

WANG Ziyun , FU Xiangzhao , WANG Yong , TONG Qinggui

2008, 31(12):1410-1414. DOI: 10.11835/j.issn.1000-582X.2008.12.016

[Abstract](548) [HTML](0) [PDF 1.84 M](189)

Abstract:
The flow of Yangtze River water in a semiannulus reentry tube was numerically simulated using a Eulerian Twophase Flow Model and computational fluid dynamics. The results show that, for Reynolds number Re=28×104, silt particles with representative diameter ds=0030 3 mm are separated in reentry tubes of all curvature (R/r) sizes, while silt particles with ds=0010 2 mm separate only slightly. Silt particles with ds=0108 5 mm, which posses a strong separation effect, are separated relatively less in reentry tubes of R/r=10~40 than in tubes with other R/r sizes.

17 Noncontact detection of the rotted points on the coating surface of the undersea pipelines

HU Ge , ZHANG Shengtao , XIANG Bing

2008, 31(12):1415-1419. DOI: 10.11835/j.issn.1000-582X.2008.12.017

[Abstract](774) [HTML](0) [PDF 1.56 M](206)

Abstract:
In the deep sea, direct measurement of pipeline cathodic protection status is very difficult. We explored a noncontact method by measuring the potential distribution of the environment field around the undersea pipelines to detect the rotted points on the coating surface. It included two aspects: developing a new type of the solidstate Ag / AgCl reference electrode for the deep sea; useing the virtual instruments to design the environment field measurement system. The noncontact measurement system was applied in the ocean of Qingdao city, P.R.China as experiments. The experimental results show that the noncontact measurement system within four meter distance to the undersea pipelines, can accurately detect rotted points.

18 A concentration and diffusion model of particulate pollutants in transition room environments

ZHU Xiaolong , XIE Zhijiang , LIU Changchun , TONG Ying

2008, 31(12):1420-1425. DOI: 10.11835/j.issn.1000-582X.2008.12.018

[Abstract](626) [HTML](0) [PDF 1.67 M](213)

Abstract:
We developed an integral concentration and diffusion model based on the aerosol theory. We studied the representation method and actualization process for pollution substances under stable and unstable status using the integral concentration model. We studied modeling and computing processes based on reflecting and absorbing barriers using the diffusion model. The model we developed can improve understanding of the change and distribution rules of inner pollution particles in transition rooms. Moreover, it provides a reference for environmental quality control and evaluation, and troublefree operation of the laser experimental system.

19 Chemical structural characteristics of microbial flocculant

XU Longjun , XU Hongliang

2008, 31(12):1426-1429. DOI: 10.11835/j.issn.1000-582X.2008.12.019

[Abstract](738) [HTML](0) [PDF 1.48 M](237)

Abstract:
Active bacteria from activated sludge in Tangjiaqiao sewage treatment plant were enriched, cultivated, separated and purified, and their degree of activity tested. Structural characteristics of the microbial flocculant produced by the activated bacteria were analyzed using coloration reaction and Fourier transform infrared spectrometry. The results show that the most active bacterium is saccharomycetes with a flocculation ratio reaching as high as 95%. Yellow crystal microbial flocculent was obtained through fermentation cultivation, separation and purification from these saccharomycetes. Results of the coloration reaction and infrared absorption spectrometry indicate this microbial flocculent is a type of sugar in which there are numerous functional groups.

20 Impact of chloride ion on undegradable landfill leachate treatment by electrochemical oxidation

LIU Yong , LIU Dan , ZHAO Shilin , ZHANG Aiping , LI Ruizhen

2008, 31(12):1430-1435. DOI: 10.11835/j.issn.1000-582X.2008.12.020

[Abstract](880) [HTML](0) [PDF 1.81 M](158)

Abstract:
We investigated the removal effects of chloride ion on treating organic substances with electrolysis using leachate from semiaerobic bioreactors. The experimental results show that, under the given conditions, the removal efficiency of refractory organic substances increases with rising initial chloride ion concentration in leachate. The impact of chloride ion on removal efficiency mainly is influenced by the initial chloride ion concentration and the chemical oxygen demand (COD) in leachate. The impact of chloride ion on the specific electric consumption of removal COD is obvious when the initial chloride ion concentration is lower. No obvious change of this impact is observed when the chloride ion concentration exceeds 125 g/L. Meanwhile, the more obvious impact of initial chloride ion concentration on organic substance removal is observed when the COD concentration in leachate is lower.

21 Gas seepage characteristics of briquette samples in a stress field

HUANG Qixiang , YIN Guangzhi , JIANG Yongdong  , YI Jun

2008, 31(12):1436-1440. DOI: 10.11835/j.issn.1000-582X.2008.12.021

[Abstract](657) [HTML](0) [PDF 1.67 M](191)

Abstract:
A new apparatus was constructed to investigate the impact of various loading conditions on the permeability of coal specimens. Test results show that loading condition has a definite influence on the permeability of coal specimens. Higher pressures lead to lower permeability, and it seems that the confining pressure has a greater effect than the axial stress does, while the permeability is related exponentially to applied stresses. Based on the experimental results, an equation governing gas seeping through coal seams is deduced within the frame of Darcys Law, which may be helpful to understand the permeability properties of stressed coal seams and to improve the drainage of gassy coal beds.

22 Plastic upper bound theory reliability analysis of coal gangue hills

LI Dongsheng , LIU Dongsheng , WANG Yukun

2008, 31(12):1441-1445. DOI: 10.11835/j.issn.1000-582X.2008.12.022

[Abstract](609) [HTML](0) [PDF 1.82 M](1229)

Abstract:
We established the plasticity limit analysis reliability limit state equation and the reliability calculating formula for gangue hills using the JC method. This work was based on the plasticity mechanics limit analysis upper bound theory and traditional slice methods. A reliability index of gangue hill stability was derived using this equation. It was found that the safety coefficient of gangue hills derived by the limit state equation risks failure if the variability of cohesion and internal friction angle are not considered. When the variability of the strength parameters rises, the reliability theory more consistently projects practicality than the limit state equation for gangue hill stability assessment.

23 Numerical simulation of the mechanism of atypical dynamic phenomena in mines

TANG Jianxin , KANG Qinrong , ZHANG Weizhong

2008, 31(12):1446-1450. DOI: 10.11835/j.issn.1000-582X.2008.12.023

[Abstract](687) [HTML](0) [PDF 1.72 M](1007)

Abstract:
An atypical dynamic phenomenon of mines, including its action forms and definition, were put forward, based on the mining accident at the Furong Mining Group Company in Sichuan, P. R. China. The mechanism of the atypical dynamic phenomenon was revealed by analyzing rock stress distribution, calculating the first and cycle broken distance of each thick and hard roof, and analyzing the balance structure of broken rock based on the threedimensional finite element software. The first stratum of the bent, sunken, aged strip was influenced by the geological conformation and the coal mining activity. This created the first break of the key stratum and led to the atypical dynamic phenomenon. We show that the key factors affecting the phenomena are the roof and floor structures, surrounding rock, and initial stress and rock burst tendency of the key stratum.

24 The effect of moisture content on the tendency of coal to combust spontaneously

JIANG Deyi , LI Lin , BEAMISH B Basil

2008, 31(12):1451-1454. DOI: 10.11835/j.issn.1000-582X.2008.12.024

[Abstract](951) [HTML](0) [PDF 1.73 M](2440)

Abstract:
The selfheating of coal is influenced by many factors, but mainly it involves exothermic reactions between reactive sites in the coal and oxygen from the air. Moisture affects the nature of the radical sites where oxidation occurs, and affects the tendency of coal to combust spontaneously. Adiabatic tests show the coal selfheating rate increases as the moisture content increases. At approximately 40% to 50% of the moisture holding capacity of the coal, the selfheating rate becomes measurable. Above this critical level of moisture content, the heat produced by oxidation is dissipated by moisture evaporation and coal selfheating is significantly delayed.

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