Journal of Wuhan University of Technology

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Vacuum Distillation Purification of TlBr Materials and Research on the Properties of TlBr Single Crystals for Roomtemperature

ZHENG Zhi-ping，MENG Fang, QUAN Lin, WANG Jing, 
GONG Shu-ping, ZHOU Dong-xiang

. 2011, (3): 1-5.

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Vacuum distillation (VD) was utilized to purify thallium bromide (TlBr) materials. The influences of vacuum distillation process on the properties of the wafers for TlBr detectors were reported. Firstly, thallium bromide (TlBr) was synthesized by chemical precipitation from TlNO3 and HBr, and purified by vacuum distillation at a temperature of 520～640 ℃. The purification efficiency and impurity concentration were evaluated by inductively coupled plasma mass spectroscopy (ICPMS). Then one of the purified materials was chosen to grow crystals with 8 mm diameter by vertical Bridgman method. The result of ICPMS showed that concentration of impurities decreased by an order of magnitude after vacuum distillation purification. The XRD patterns of the wafers cut from the crystals showed that the crystals were preferentially oriented in the \[110\] direction. The TlBr wafers had a high resistivity of 109Ω·cm, as well as better optical properties. The wafers can be used for the preparation of TlBr detectors.

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Study on the Secondorder Optical Nonlinearity of As2-S3 Glass

ZHENG Xiao-lin, ZHOU Xue-dong, ZHAO Xiu-jian

. 2011, (3): 6-9.

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As2-S3 glasses that suit for the fabrication of fibers were prepared by the conventional meltquenching technique. Their transmissivity, thermal properties, Raman spectra, secondorder optical nonlinearity and stability were studied. The results indicate that second harmonic generation (SHG) could be induced in As2-S3 glass after thermalelectric poling, but the stability of SHG was weak. Raman analysis indicates that no obvious structural changes have been induced in sample after poling. A largest secondorder nonlinear susceptibility of 0.38 pm/V could be obtained in the samples after poling at 5 kV、100 ℃ for 40 min. With the addition of Na+, the stability of SHG can be enhanced obviously, this will be beneficial for the real application of As2-S3 glasses in the infrared optoelectronic devices.

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Preparation of Bismuthate Glassceramics Used for Sealing

ZHOU Junlin,LU Anxian,LI Jing,LUO Zhiwei,LI Shaohua,LI Jianghua

. 2011, (3): 10-14.

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The bismuthate glass and glassceramics were preprared by conventional meltingquenching method and lowtemperature sintering method of glass powder,respectively. Differential scanning calorimetry (DSC) ,X-ray diffraction (XRD), thermal expansion coefficient , bending strength measurement were used to study the characteristic temperature and crystallization of basis glass ,the effects of thermal treatment temperature on crystallization of the glasses as well as thermal expansion coefficient ,bending strength of the glassceramics.The results showed that the thermal expansion coefficient of the basis glass increases with increasing content of Bi2O3,the glass transition temperature and softening temperature of the basis glass decrease with increasing content of Bi2O3. When the glasses were treated at lower temperature,the types of crystalline phase in glassceramics with different Bi2O3 content were the same.However,the types of crystalline phase were different ,when the glasses were treated at higher temperature. When the glasses were treated at 400 ℃、500 ℃、600 ℃, 50Bi2O3-20B2O3-15ZnO-10BaO composition of glass were precipitated Bi45BO69/Bi2O3、Bi2O3/Bi24B2O39 and Bi24B2O39 ,respectively,but 65Bi2O3-5B2O3-15ZnO-10BaO composition of glass were precipitated Bi45BO69/Bi2O3、Bi2O3 and Bi38ZnO58,respectively.

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Study of Nanocrystalline Magnesiumaluminum Spinel Transparent Glassceramic

TANG Liying, WANG Jing, YANG Kun, CHENG Jinshu

. 2011, (3): 15-18.

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The transparent MgOAl2O3SiO2（MAS） glassceramic doped with TiO2 and ZrO2  as nucleation agents was prepared by traditional twostep heat treatment. The specimens were analyzed by Xray diffraction, scanning electron microscopy , field emissionenvironment scanning electron microscope(FESEM) and UV scanning spectrophotometer. Only one crystal phase namely magnesiumaluminum spinel (MgAl2O4) exists below 1 000 ℃. The βquartz phase precipitates at 1 050 ℃, while the main crystal phase is still spinel. The precipitation of spinel crystal phase makes the UV cutoff wavelength increased. With the increase of crystallization temperature, the grain size gets bigger, and the light transmission of glassceramic becomes lower. After the heattreatment at 830 ℃/4 h+950 ℃/1.5 h, the mean grain size of the specimen is only 25.6 nm , and the UV cutoff rate of this specimen is 100%, while the transmission is 62% in visible light region.

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Cation Dependence of Structure in Alkali Germinate Glasses

ZHANG Changjian, TANG Gang, LU Anxian

. 2011, (3): 19-25.

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The structure and germanate anomaly of binary xR2O(1-x)GeO2 (R= Li, Na, K, Rb, Cs) series glasses are investigated by Raman spectrum, IR, density test. The results show that: 1) Li+, Na+, K+ have the same effect on the infrared spectra of xR2O(1-x)GeO2 (R= Li, Na, K) series glasses. Upon the addition of R+, the high absorption frequency band at 700～900 cm-1 gradually shifts to lower frequency while there is an increase in the wavenumber of the low absorption frequency band at 500～700 cm-1. However, when the alkali metal content is large enough, the low absorption frequency moves to lower wavenumber. Rb+, Cs+ affect the infrared spectra of xR2O(1-x) GeO2 (R= Rb, Cs) series glasses in the same way. 2) While the content of R2O reaches up to the “germanate anomaly” point, there are still \[GeO4\] 6membered rings in the network of xR2O(1-x)GeO2 (R= Li, Na, K) series glasses. Rb+, Cs+ affect the Raman spectra of xR2O(1-x) GeO2 (R= Rb, Cs) series glasses in the same way. However, at the “germanate anomaly” point, the scattering peak at 435 cm-1 disappears which indicates that there are no \[GeO4\] 6membered rings in the network.With further increasing the amount of Rb+，Cs+, the Ge—O—Ge bending vibration is active in the Raman spectra. 3) The field strength per unit volume of alkali cation is the prominent structural change responsible for changes in the structure of xR2O(1-x)GeO2 (R= Li, Na, K) series glasses .For the potassium and rubidium, the relative atomic mass per unit volume of alkali cation has the greater impact on the density of alkali germanate glasses.

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Numerical Simulation of the Effect Rule of the Burners’ InstallationHeight on Combustion Space in Oxyfuel Glass Furnace

XIE Junlin, JIN Mingfang, MEI Shuxia

. 2011, (3): 26-31.

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In this paper, numerical simulation with software FLUENT was carried out in combustion space of an oxyfuel glass furnace.On the oxyfuel combustion conditions, when the burners installed in three different heights of the furnace,compare and analyze their temperature fields, flow fields and the erosion of the crown by alkali volatilization in combustion space ,which can provide basis for operating parameters of the burners and instruct the design and optimization effectively in oxyfuel glass furnace.Our research shows that the burners’ installation height has a great effect on temperature fields of the combustion space and inappropriate installation height will result in decreasing of the heat transfer efficiency to glass surface and increasing of the alkali volatilization. When the burners installed at the height of 0.3 m, the gas flow tends to wash out the melted glass surface and has great average velocity; when the burners installed at the height of 0.5 m,the flame gas flow tends to go upwards and the average mole fraction of water vapor is obviously high near the bottom of the combustion space, which causes alkali vapors volatilize; when the burners installed at the height of 0.4 m, volatilization rate of alkali is the least,but high temperature zone appears in the crown and the heat transfer efficiency is not high.Therefore,the reasonable installation height of burners should be between 0.3～0.4 m.

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Study on a Novel Nano CeO2containing Glass Antifogging Agent

XU Huan，XIONG Liping，WU Yifeng，ZHOU Xiang，HE Zhongyi

. 2011, (3): 32-35.

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In this paper, nitric acid and H2O2 were usedto obtain the nanocrystalline CeO2 solid. Then used the alcohol and isopropanol as solvent, glycol and glycerol as additives, by adding some nanocrystalline CeO2 solid and surfactant, and some water as the stuff of the antifogging agent. By using the singlefactor optimization, the best group was selected as the formula of the antifogging agent.The obtained antifogging agent in this paper is not only good in terms of antifogging time and antifog frosting effect and easy to be prepared.

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Regulation of Ultrasonic on PAN Precursor Fibers and Preoxidation

GE Bao, WANG Yuansheng, SHI Jimei, YUAN Huiwu, REN Xiaomeng

. 2011, (3): 36-39.

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In order to research the regulation of ultrasonic on PAN precursor fibers and preoxidation. Differential scanning calorimetry (DSC), Fourier transform infrared spectrometry (FTIR) and wide angle Xray diffraction (XRD) were used to study the thermal properties, structural change and microcrystal size in preoxidated fibers. These results show that, the initial reaction temperature of PAN precursor fibers with ultrasonic treated become lower and the exothermal extent's expanded. The heatresistant trapezoid structure of PAN fibers with ultrasonic treatment can be formed in lower temperature and the microcrystallite size of PAN fibers with ultrasonic treatment increases from 10.39 nm to 11.18 nm.

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Preparation and Properties of Antimicrobial Polyvinyl Alcohol / Alginate Blend Foams

FAN Lihong,ZHOU Yue,PAN Xiaoran,ZHENG Hua

. 2011, (3): 40-45.

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Based on polyvinyl alcohol (PVA) and alginate, antibacterial foams were prepared by adding antimicrobials into acetalization process. IR and XRD demonstrated the existence of acetalization process. SEM indicated interconnected and opencell structures of the PVA/alginate foams with large pore size and high porosities. The properties tests show that the best value of water absorption was obtained when alginate content was 20%. The largest tensile strength and breaking elongation of the blend foams were 0.24 MPa and 428.04% when alginate content was 30%. The foams containing higher nanosilver dispersion showed effective antimicrobial activity.

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Study on Oxidation of Cyclohexanone to ε-caprolactone over WO3/Al2O3  Catalyst

OU Huaqiang，ZHANG Guangxu，HU Changlin，CHENG Dongen, HU Zhangyan

. 2011, (3): 46-49.

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The WO3/γAl2O3 catalyst for twostep synthesis of ε- caprolactone through catalytic reactive distillation was prepared by cocalcination method. The effects of various reaction conditions such as reaction temperature, reaction time, packed tower height, amount of catalyst and raw material consumption were investigated. Under the optimum conditions, the conversion of hydrogen peroxide was 95.8%, yield to εcaprolactone was 71.2%.

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Preparation of TiO2-SiO2-Al2O3 Composite Sol by Titanium Slag and Its Properties

. 2011, (3): 50-53.

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In this paper, TiO2-SiO2-Al2O3 composite sol was prepared using blast furnace slag containing high content of titanium constituent from Panzhihua Iron and Steel Company as raw materials through the following process, alkali metal salt fusion by calcination at high temperatures, dissolution in water and ion exchange, etc. The parameters affecting the dissolution rate of TiO2-SiO2-Al2O3 constitunets from slag were investigated. The degradation of methyl orange in the composite sol under natural light and its photocatalytic properties were tested by UV visible spectrophotometer. The results showed that the optimal process parameters for preparing the TiO2-SiO2-Al2O3 composite sol were: the ratio of alkali metal salt and slag 0.96, calcinating temperature 1 100 ℃ and holding time 120 min. When the pH value of composite sol was 2.0 the degradation efficiency of the methyl orange solution with initial concentration of 10 mg/L was up to 98.4% under the condition of illumination time of 80 min under natural light.

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Research on Hydration Reactivity of Microsphere Compared with Silica Fume and Fly Ash

DING Qingjun，HAN Jiyu，HUANG Xiulin，GONG Zicheng

. 2011, (3): 54-57.

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In order to carry out the investigation of the hydration reactivity of microsphere and compare with silica fume and fly ash, several modern testing techniques including Laser Particle Sizer, Xray Diffraction, Scanning Electron Microscope, Thermogravimetic Analysis, Tam Air and Infrared Spectroscopic Analysis have been adopted in this article. The results showed that the hydration reactivity of microsphere was between silica fume and fly ash.

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Friction Characteristics of SF-1 Waterlubricated Stern Tube Bearings

DAI Mingcheng，LIU Zhenglin，FAN Faxiao

. 2011, (3): 58-61.

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Aiming at the current situation and shortcomings of the traditional waterlubricated stern tube bearings, friction properties test of the SF1 polymer graphite bearing under water lubrication was done on the SSB100 model stern tube bearings testing machine. And the effects of load, linear velocity and the temperature of lubricating water on the law of friction coefficient and wear properties were researched. The test results show that SF1 material is of outstanding selflubricating property, low frictional factor, high pressurebearing capability and wear resistance, which can be applied broadly in the shipbuilding industry.

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Optimization Analysis of Heat Transfer Enhancement in Tube by Filling with Annular Metallic Porous Medium

MING Tingzhen, ZHOU Cheng,LIU Wei

. 2011, (3): 62-66.

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In order to enhance heat transfer rate of tube flow, the inner part of fullydeveloped laminar tube flow is filled with annular metallic porous medium, and mathematical models to describe its flow and heat transfer characteristic are established in this paper, which emphasize the different temperature, velocity and PEC results of enhanced tube with different positions of metallic porous medium. Numerical simulation results show that the temperature and velocity of the zone filled with metallic porous medium are very uniform, while the temperature and velocity gradient are very large in the flow without metallic porous medium, which shows that heat transfer between the wall and the flow is enhanced greatly. In addition, it is appropriate, for a certain constant filling area, to fill the core flow with metallic porous medium in order to achieve a comparatively higher PEC value of the enhanced tube.

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Experimental Study on Evaporating Heat Transfer Characteristics of HFC-245fa

HUANG Xiaoyan,WANG Hua ,WANG Huitao

. 2011, (3): 67-71.

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Convective boiling heat transfer characteristics of R245fa inside horizontal tube are investigated at various mass flow rates of hot water, working fluids and at various evaporation temperatures. The investigation results show that convective boiling heat transfer coefficients goes up with the increase of hot water and working fluid mass flow rate, but it is contrary to evaporation temperature. By comparisons of the experimental local heat transfer coefficients with that predicted by Chen correlation，LiuWinterton correlation and Shah correlation，it is concluded that deviations of these three correlations are 31.6%、6.3%、37.4% respectively. LiuWinterton correlation is more precise to predict convective boiling heat transfer coefficients of R245fa than Chen correlation and Shah correlation.

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Vehicle Scheduling in Container Terminal Based on Reinforcement Learning

SHANG Jing，XU Changsheng

. 2011, (3): 72-76.

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Scheduling strategies of container vehicles which serve loading and unloading simultaneously were researched. Scheduling optimizing object was reducing the waiting time of quay cranes for vehicles and empty travel distance of vehicles. A reinforcement learning model based on Qlearning was designed, and its system states, action rules and reward function were defined. The Qfunction was generalized and approximated using the cerebellamodelarticulationcontroller (CMAC) neuron network. Simulation results showed that Qlearning algorithm could optimize the vehicle scheduling strategies, which guaranteed the quay cranes’ continuous working and reducing the empty travel distance of vehicles efficiently.

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Performance Evaluation of Chinese Transportation Industry Based on DEA Method

DING Xiaodong，XU Ling， YAO Zhigang

. 2011, (3): 77-81.

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By adopting CCR performance evaluation model of DEA and constructing six input indicators and five output indicators through PCA (principal component analysis), the China’s transportation industry is evaluated and its performance is solved by LINGO. Through the performance index analysis, the author pointed China’s transportation industry can be divided into four phase in the 30 years and its performance index will not decline but enter the new development cycle in 2013.Using factor weights analysis, the author found out the transportation line investment and turnover are the core factors which effect the transportation performance .The author suggested that the highway , international routes and railway should increase investment and the central core of railway transportation and waterway transportation should be emphasized.

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Test and Model Parameter Analysis of Asphaltic Sand with Viscoelasticity

LI Xiaojun,JIANG Lihua

. 2011, (3): 82-86.

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〗In this paper, uniaxial creep tests are conducted with asphaltic sand under 6 loading stress at 20 degrees centigrade. The viscoelasticity is analyzed separately with Burgers model. After fitting the model parameters using Origin7.5 software, the constitutive equation expression of asphaltic sands’s viscoelasticity can be obtained. Contrast model predicted values and test results, and analyzed the influence of model parameters to the creep equation. The result indicates that Burgers model can reflect asphaltic sand’s viscoelasticity well. And the stressstrain tautochrone indicates that the evolution of asphaltic sand displays the obvious misalignment characteristic. Besides, in Burgers model, elastic parameter E1determines the initial position (t=0) in creep process, elastic parameter E2 controls curve range in the first stage, viscosity parameter η1 determines the slope of the creep curve in the second stage, and viscosity parameter η2 controls bending extent of the creep curve in the first stage.

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Study of Concrete Block’s Thermal Stress Considering Tensile and Pressure Different Creep

HUANG Yaoying，ZHENG Hong，ZHOU Yihong

. 2011, (3): 87-92.

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The solution of elastic creep equation under varying stresses with tensile and pressure different creep was studied; the finite element method calculation formula of elastic creep equation under varying stresses with tensile and pressure different creep was deduced by stress increment on the basis of the theory of concrete creep depending on concrete age and the assume of linear superposition in this paper. Since the creep rates of tensile and pressure were the same, it was assumed that the creep strain increment recursion formula of tensile and pressure same creep was the same in form with that of tensile and pressure different creep. When the principal stress increment was negative value, the pressure creep was adopted; when the principal stress increment was positive value, the tensile creep was adopted. It is indicated by tensile and pressure different creep simulation in practical concrete engineering that concrete block’s stress loadingandunloading periodicity is influenced by diurnal amplitude in high temperature seasons. The concrete temperature stress calculated by tensile and pressure different creep is bigger than that calculated by tensile and pressure same creep, and this stress will increase as the pouring interval prolongs.

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Numerical Modeling of Saturatedunsaturated Earth Dam During Descent of Reservoir Water Level

XU Yangjun，ZHANG Guomin，LIU Xiaohe，XIA Yuanyou，LI Xinjun

. 2011, (3): 93-97.

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Based on seepage theory of unsaturated soil, a numerical modeling was carried out on saturatedunsaturated earth dam during descent of reservoir water level by the FEM software named Geoslope. The analysis results obtained include dissipation of excess pore water pressure, variation of water level with the descent of the reservoir water level. It’s shown that, in saturatedunsaturated earth dam, the time curve of water level in the dam took on the appearance of being gibbous, and the velocity of the dissipation of excess pore water pressure became slower, due to the part of unsaturated soil of the dam.

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Analysis and Research of Concrete Image Processing Methods Based on X-ray CT

ZHAO Liang, LI Changhua, DANG Faning, CHEN Dengfeng

. 2011, (3): 98-102.

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With the combination of the newlydeveloped devices and medical CT technology, CT vertical section images are formed under uniaxial pressure. This paper analyzes the process of CT images by two ways: method of edge pick up and method of different image. It is found that image resolution was affected by the processing result of concrete CT image. So the author offers a modified version of the metropolis dynamics（MMD） simulated annealing arithmetic to evaluate the fracture in concrete vertical setion. According to the experimental results, the method in this paper can do better in the image segmentation and help the further research on concrete mesostructure.

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Carbonation Depth Prediction of Concrete Structures Based on Bayesian Approach

WU Benying，ZHOU Xiwu

. 2011, (3): 103-107.

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The specific condition of the actual project structure should be considered the specific condition of the actual project structure in the prediction of carbonation depth. The thought of dynamic information updates based on Bayesian approach was introduced in paper. A Bayesian prior model is proposed based on epistemic information from the empirical formula. Two types of the information, the epistemic information and the natural information from the practical structural inspection, are synthesized by Bayesian approach and inferred to update the prior model. The approach inherits the completeness of the prior model and the accuracy of inspection information. Carbonation law for the concrete structure is assessed and forecasted more accurately by the Bayesian approach. Case study illustrates the practicability and advantages of Bayesian dynamic information updates.

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Research Safety Earlywarning Method for Roof Latticed Structure of Wuhan Natatorium

WANG Jing,LIU Hui,YANG Li,QIAN Bin，QU Weilian

. 2011, (3): 108-111.

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Taking roof latticed structure of Wuhan Natatorium as engineering background, according to the structural characteristics, the structural safety earlywarning method is proposed in the paper. It is great trouble of Wuhan Natatorium roof since the “V” shape skylights located on the roof. Therefore, the key to realize the structural safety earlywarning is to establish finite element model of “V” shape skylights acted by snow load and to detect firn thickness on the roof. Based on the phenomena constitutive equation of snow, the finite element model of gutter board with firn used for structural safety earlywarning is established according to climate characteristics of Wuhan city. Due to the map relationship between the strains of “V” shape skylight with firn thickness, the strain information is measured by strain gauges installed on the “V” shape skylights; the firn thickness is detected by fuzzy pattern identification methods. The target of safe earlywarning for firn thickness of the latticed structure can be achieved.

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Analysis on the Influence of Building Envelope to Public Buildings’ Energy Consumption

WANG Qiankun,WAN Chang

. 2011, (3): 112-115.

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By using DeSTc software, this paper takes a proposed public building as research object, analyzes the influence of exterior walls, roof, exterior windows and the whole building envelop with different thermal property respectively, obtaining the different influence of building envelop thermal property to buildings’ heat load and cooling load, as well as the energysaving potential.

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Research on Internationalization BPSM Strategy Model of Engineering Survey and Design Enterprises

PENG Shou

. 2011, (3): 116-120.

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In the 21st century, the engineering survey and design enterprise ,which is under intense competition in the domestic market, for conforming to the trend of internationalization, is actively implementing the strategy of internationalization. However, concerning the present situation of the implementation, the internationalization of the engineering survey and design enterprise is still at the exploratory stage, a lot of enterprises have not yet established a relatively complete system of international strategy. Based on this, on the basis of the theories of internationalization and strategic analysis of the engineering survey and design enterprise, this paper constructs the BPSM strategic model which is composed of “main business (B) integration, business process (P) recycling, services (S) network restructuring, the core management (M) system architecture” as core content, and uses "carrier" strategy and "base" strategy to prove the applicability and validity of the BPSM strategic model.

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Preparation of Mullite from Lowgrade Kaolin

ZHOU Huamei, QIAO Xiuchen, YU Jianguo

. 2011, (3): 121-125.

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This research investigated the preparation of mullite with an Al2O3∶SiO2 ratio of 3∶2 from Suzhou lowgrade kaolin by direct calcination and the calcination with the addition of Al(OH)3. The phase transformations of samples calcined between 1 000 ℃ and 1 500 ℃ for an hour were investigated using XRF, DTA, XRD and IR measurements. The results showed that a 3∶2 type mullite without the presence of cristobalite was formed in kaolin calcined at 1 500 ℃. The formation temperature of mullite was lowered down to 1 300 ℃ after adding Al(OH)3, however, the crystalline degree of mullite formed was lower. Although the increase in calcination temperature can increase the crystalline degree of mullite, the alumina content of mullite decreased due to the formation of corundum.

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Effects of Calciumbased Desulfurizing Absorbents on the Emission of Arsenic During Coal Combustion

YANG Hua

. 2011, (3): 126-129.

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In order to be more specific research the dearsenic characteristics of calciumbased desulfurizing absorbents during coal combustion .The influence on the dearsenic rate of different factors are investigated including the type, Ca/S, particle of calciumbased desulfurizing absorbents and the combustion temperature. The result shows that the amount of calciumbased desulfurizing absorbents is 2.0, the particle size of calciumbased desulfurizing absorbents top 200 mesh, dolomite has the best dearsenic ability and it’s dearsenic rate still could reach 65.71% in 1 200 ℃ high temperatures. Therefore the calciumbased desulfurizing absorbents not only can captue suifur but also was good to inhibit the volatile of arsenic during coal combustion.

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Anammox Process in the Presence of Organic Carbon Source

ZHANG Shaohui，LI Cong

. 2011, (3): 130-135.

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The metabolism of anammox process in the presence of organic carbon source was studied through continuous cultivation and batch tests in serum bottles. Maintaining pH8.0, 30 ℃ and HRT 1 d, the stable removal of ammonium, nitrite, nitrate and acetate were attained after the autotrophic anammox sludge was cultivated for 145 days with synthetic wastewater containing nitrogen and 1.16 mmol/L acetate, and the acetate in low concentration promoted the anammox process. The suitable molecular acetateC/NH+4N ratio was 0.73 for anammox process in the presence of acetate, while the anammox reaction was pronouncedly inhibited as the acetateC/NH+4N was higher than 1.04. The batch tests indicated that, in the presence of acetate at low concentration, the anammox bacteria had versatile metabolism pathways, i.e. mediating both autotrophic anammox reaction and heterotrophic denitrification.

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Effects of Different Cylinder Surfaces on Diesel Engine Vibration

GUO Zhiwei, YUAN Chengqing, YE Fenghua, LIU Peng,YAN Xinping

. 2011, (3): 136-140.

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The tribological system of cylinder linerpiston ring was regarded as the research object. The surface of each cylinder was treated where some pits and grooves were made. The cylinderpiston ring simulation experiments were then investigated using a tester. The vibration signals during testing were collected.The comparison analysis of diesel engine condition body surface vibration signals between conventional cylinder and a variety of surface treatment of cylinder was conducted. The wavelet packet decomposition with the reconstruction was used to obtain a high frequency signal components and extract its energy characteristics. Through comparing the characteristics of the value on the cylinder with different surface treatment, the effects of cylinder surface on diesel engine vibration were gained.

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Influence of Valve Plate Groove Structure on Its Stress Distribution

WANG Jing， LIU Zuomin, DONG Bing,LI Songyan

. 2011, (3): 141-144.

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By using the finite element method and building parametric model of valve plate, applying ANSYS to the valve for thermal stress coupling analysis,the effect of the stress distribution of the design parameters of valve groove on plate and transition arc part has been investigated. The results show that compared to the groove chord length and sagitta parameters,the radius of the valve groove greatly affects its stress distribution. The researchers can provide theory basis for the failure analysis and the groove structural design of the valve.

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Effect of Circularity Error of AMB on its Dynamic Properties

LIU Xiaojing ，MEI Ronghai

. 2011, (3): 145-148.

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The paper analyse the circularity error of the surface of the magnetic bearing rotor,the
effect of circularity error of AMB on current stiffness and displacement stiffness is analyzed,and analyse the effect of circularity error of surfacethe on stepinterference under conventional PID control. The results show displacement stiffness and current stiffness is nonlinear changing,which is not conductive to system stability. The circularity error effects overshoot and adjusting time of system under stepinterference. Fixed PID control parameters can reduce the effect.

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Optimized MIMO Algorithm for LTE Downlink Transmission

LIU Kewen,LIU Quan,MA Zherui

. 2011, (3): 149-152.

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This work deals with the existed problems in medium and highspeed scenes, based on the present LTE MIMO technology, an optimized MIMO scheme is presented in this paper. It uses the minimum error probability as the criteria to predict the feedback channel information. The performances of the optimized algorithm and implementation complexity have been analyzed. The results show that it not only achieves the good tradeoff between the system capacity and coverage quality, but also can avoid excess complexity overhead.

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Game Theory Power Control Algorithm Based on Nonlinear Pricing Function

XU Jianxia，LIU Huiheng, LIU Kezhong

. 2011, (3): 153-156.

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Considering the characteristic of game power control algorithm in cognitive radio, the pricing function is improved and power control game via nonlinear pricing function based on signaltointerference ratio （NPGPNL）is proposed, then the existence and uniqueness of the nashequilibrium are proved. Meanwhile, NPGPNL is simulated via Matlab, and the simulation results show that NPGPNL not only reduces emission power of cognitive user and improves the utility, but also takes into account the system fairness to some extent.

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Fair Resource Allocation for Relayaided OFDMA Networks

DING Enjie ，ZHANG Guopeng

. 2011, (3): 157-160.

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To acquire a fair subcarriers and power sharing in the multiuser RelayAided OFDMA (OFDMA/Relay) networks, a maxmin rule based resource allocation scheme is proposed in this paper. Using the maxmin rule, the resource allocation problem is modeled as an optimization problem to maximize the minimum of all users’ data rates. As the result, the identical data rates of the best effort user traffics’ are obtained in the network while their BER (bit error rate) constraints are satisfied. Simulation results show, by using the proposed OFDMA/Relay resource allocation scheme, the starvation phenomenon, i.e., the date rate of the user stations who have poor channel conditions with the Base Station and the Relay Station are almost zero is avoided.

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Identity Authentication Based on Fuzzy Vault

LI Fen, LIU Quan, PANG Liaojun, PEI Qingqi

. 2011, (3): 161-164.

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A scheme named strong twofactor authentication was proposed, to resolve the possible issues of digital identity illegally used by attackers. We stored the generated digital certificate and its private key in a smartcard and protected the PIN of the smartcard by fuzzy vault. The security was improved obviously through combining two kinds of factors to prove one’s identity. Meanwhile in order to relieve the computational burden of the smartcard, we imported secret sharing. Only when both the information of the smartcard and the fingerprint server are acquired, would the binding PIN of the smartcard be released. This scheme further perfects the authentication of PKI and is suitable for the authentication of highend users or high safety customers with special requirements.

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