2012 volumne 33 Issue 04
ZHU Haitang,WANG Yizhong,LI Jinzhang
Abstract: Based on the material character of BFRP rebar and the plastic method for conerete structure. theconcept on nominal yield strength of BFRP rebar was proposed, the yield condition of concrete and BFRP re-bar were determined, and the failure mechanics of two-way BFRP rebar reinforced conerete slabs under centraconcentrated load was established. The calculating expression on plastic solution of ultimate punching capacityfor two-way BFRP rebar reinforced conerete slabs under central concentrated load was educed using the virtual work principle.
ZHENG Yuanxun,CAl Yingchun,ZHANG Yamin
Abstract: To study the similarities and differences of force and deformation of asphalt pavement under single roundand two round loads, and to verify the effectiveness of using single round uniformly distributed load equivalent two.round uniformly distributed load. Firstly , the deflection and stress of asphalt pavement under two-round uniform dis.tributed load were studied, and then the comparative stress analysis of asphalt pavement under single round and tworound loads based on elastic layer theory and numerical simulation study by dynamic loading of double-and singleround were carried out. The results show that: both in the statie and dynamic load mode, except some differencesexisting in the road surface, with the increase in the depth of the pavement structure, deflection and stress trendsand size are consistent for single round and two round loads, which means that with a single round uniformly distrib.uted load equivalent to two-round to design and testing is feasible and effective.
WANG Tao,LI Yu,BAI Hua,etc;
Abstract: Reasonable strong seismic motion records are selected according to the applicable Code of SeismicDesign for Railway Engineering. By using FEA software, the FEA model of one double-column pier of passen-ger dedicated line is established with considering the effect of flexible base elfects and seismic characteristic.Based on Park-Ang seismic damage model and nonlinear seismic response analysis, the seismic damage analy.sis on double-column pier of passenger dedicated Line is carried out. The study results are obtained as follow :1 ) T’he seismic damage of bridge mainly happen during the early and middle stage of seismic motion, 2) Thereare still major discrepancies in the seismie damage made from the seismic records which come from the samegite condition and have the same PGA. 3) Although PGA has a great elfect on the seismic damage index, ithas nothing to do with the happening time of max seismic damage index.
LI Yun,WU Xiaoping,LIAO Qunli
Abstract: The choice of maintenance project for existing railway tunnel lining crack is influenced by many fac.tors, including the investment costs, the natural environment and feasibility degree. In response to these fac.tors, this paper uses discernibility matrix heuristie reduction algorithm, expert evaluation method and multi.level gray comprehensive evaluation method to establish a comprehensive maintenance project for existing rail.way tunnel lining decision-making model. The model weights the Index layer objectively by using Matrix Re-duction Algorithm and weights the sub goals subjectively by using expert evaluation method, which ensures thescientific consideration of the weight, At the same time, the model decides the existing railway tunnel liningmaintenanee project comprehensively by using multi-level gray eomprehensive evaluation method to ensure thereliability of the results of decision-making. Examples of application show that the method can get the desiredquantitative results obtained, and it can be used more widely.
ZHAO Zhihang,CHE Wei,FENG Qun
Abstract: The design response spectrum in seismic design code is the result of a large number of midfield andfar-field seismic records statistical regression analysis. As a result of the lack of observation data , the percent olnear-field seismie records is small , which lcads to the insufficient consideration of the frequency spectrumcharacteristic of near field ground motions. Near-fault ground motions have some important characteristie thatmake them different from far-fault ground motions. High-frequency components and low-frequency pulses ofnear-fault ground motions are among notable specifications. In this paper, a moving average filtering has beerdesigned to decompose the near-fault ground molions into two components having different frequeney contents:low-frequency pulses component and high-frequency component, The method is applied to decompose a few selected near-fault records and the elastie response of structure is examined through their response to the decomposed parts. The results emphasizes that for single pulse record the pulse component can effectively representhe response of the structure under the original records . But for multi-pulse record, owing to the existence ofone or more peaks, the pulse component can not efectively represent the structure response under the originalrecords, The sole consideration of the pulse component and ignoring the high frequency component is very badfor short cycle structure.
ZHOU Qinghua,SHA Aimin
Abstract: The creep stiffness modulus of the high modulus asphalt concrete was tested through uniaxial compression ereep test and low temperature bending creep test, Based on the test data, the influence laws of mate.rial composition to creep performance of high modulus asphalt concrete were analyzed. The results showed thalow grade bitumen and additives couid enhanee the creep stiffness modulus significantly, reduce the instanta.neous deformation and the speed of viscoelastic deformation, but the relaxation ability to flexural stress in lowtemperature also decreased.
LI Jingjing,LI Peng-fei,ZHANG Qing
Abstract: In order to analyze the changes of joint opening displacement ( JOD) of cement concrete pavemen!under different road structures and material parameters, the joint model was established by using a 3D finiteelement method, Various factors of JOD were quantitatively analyzed, The results show that JOD is significantly effected by temperature gradient, base modulus, slab length and slab thickness, and the relationship be.tween JOD and temperature gradient is the logarithmic, the base modulus is the power, and both the slablength and thickness are the exponential. Based on the above analysis, the formulae of joint changes have beenset up with the consideration of four main factors, the theoretical analysis is verified by using the measured da.ta, and the results provide the potential for the joint design and selecting the joint filler.
WANG Zhanfeng,WANG Sheliang,WENG Guangyuan
Abstract: The mechanical properties of recycled aggregate concrete( RAC )were studied with the replacementrate of0%,30%,50%,70% and 100%,such as the cube compressive strength, prism compressivestrength, spliting tensile strength, flexural strength and modulus. The test results have shown that with the re.placement rate of recycled coarse aggregate , the cube and prism compressive strength are gradually increasedthe splitting tensile strength has decreased to some extent, and the modulus is gradually decreased. Combinedwith the analysis of test data, the conversion relationship between the prism compressive strength, splitlingtensile strength , flexural strength, modulus and the cube compressive strength are established.
JIA Cheng,CHEN Huihui
Abstract: US-FE-SPIM QUAD4 element is constructed by using classical QUAD4 element isoparametric shapefunctions sets and FE-LSPiM QUAD4 element shape functions sets as test functions and the trial functions re-spectively. The former is used for requirements of intra-element and inter-element continuity in displacementfield, and the latter is for requirements of completeness in displacement field. US-FE-SPIM QUAD4 elementeould easily fulfil exaet essential boundary condition along the entire length of the edge. This element has goodprecision and insensitivity to mesh distortion, and satisfies the consistency requirement. Further studies on sta.bility of US-FE-SPIM QUAD4 element for convergence are made in this paper. Because an analytical proof ofwhether the inf-sup condition is satisfied by a specific element is difficult, in this paper, the formulation of nu-merical inf-sup condition for this element is derived and whether the inf-sup condition is satisfied for this ele.ment is tested by the numerical method. Numerical examples show that US-FE-SPIM QUAD4 element couldpass numerical inf-sup testing, satisfying the stability requirement. And this paper offers a simple way to testelement stability.
ZHANG Yinxia,Qiao Xiangnan,WANG Dong,etc;
Abstract: With the developing language of ANSYS software and the using of the double-ellipsoid heat sourcemodel, a model of two steel plate that connected by Y groove multi-layer and multi-pass CO, are welding seamis created. Three different kinds of element birth and death technology are used separately in the model. Aftcrthe comparison of three difrerent numerical simulation results, the correctness of the element birth and deathtechnology which activates the welding material step by step is validated, The temperature field distributionregularities of the welding at various time points of welding progress are analyzed. The cycling curves of typicalspots on different place of the model are studied. Based on the results , the component’s tissue, properties andresidual stress at different position of the model can be estimated.
YAO Qiguo,LI Lin,LIU Yuliang,etcl
Abstract: The mathematical equations of the Rikitake two-disk dynamo have been derived, The relationshipbetween the dynamo currents and the angular velocity of disk has been defined. It caleulated the lyapunov ex.ponent and fractal dimension of chaotic attractor. And then this paper discussed the system’s chaotic bifurca.tion behavior and the state diversification of its periodical windows, as well might appear chaotic movementpatterns. After simulating, it obtained the Rikitake two-disk dynamo’s chaotic attractors. Moreover, it ana.lyzed the system’s basic dynamic behavior such as symmetry, power spectrum, equilibrium pots, stability andso on. These chaotic behavior can be used to simulate the reversals of the geomagnetic field. Furthermore. ithas important theory signifcance and practical value.
XlAO Yougang,HUANG Dejuan,DENG Helian
Abstract: Based on virtual instrument technology,the gearbox condition diagnostics platform was developedwith multi-method, multi-parameter comprchensive application for innovative experimental teaching. UsingLabVIEW’s Datasocket technology, data exchange can be realized between server and client. On the plat.form , gearbox vibration signals can be integrated using pattern recognition technology, which are useful for theintelligent diagnosis of gearbox state. The experimental platform is helpful to stimulate students to participatein innovative experimental consciously and to develop innovation idea, innovative ability and innovative spiritThrough the communication between server and clients, a good interaetion mechanism will be formed betweenstudents and teachers.
WANG Dongxiao,GAO Xueshan,LIU Yunhui
Abstract: The intention in the present paper is to provide a novel berried-free wheelchair with a wheel-trackeddeformable mechanism for the needs in urban obstacle environment in general. To combine the advantages ofnormal wheelchair and crawler wheelchair, for example rapidity and high over-obstacle ability, we design awheel-tracked deformable mechanism and an clastic crawler which can help the wheelchair to do the mode con-version from wheel to track quickly, Moreover, it also presents a fuzzy method for adjusting the gravity centerand controlling inclination of a stair-climbing wheelchair. To validate the proposed berried-free wheelchair, wehave carried out simulations with analysis. "he results demonstrate that the wheelchair has good environmentaladaptability and high over-obstacle ability.
YANG Bokai,LU Yiyu,YANG Xiaofeng,etc;
Abstract: Calculation on cavitation bubble growth and collapse is key to study the cavitating water jet. Afterthe analysis of different numerical methods to Rayleigh-Plesset equation, a numerica! method with variable-steps is developed that can overcome the weak point of constant time step method to solve the Rayleigh-Plessetequation, And it also learned that a constant time step is not appropriate for solving the Rayleigh-Plesset equa-tion when dealing with large pressure variations or under the smaller pressure variation. The variable time stegmethod ean get a better result. What more, it is only after the variable time step method can be predictedwithout singularity, So the variable time step method is batter than the constant time step method in savingcomputational and keeping accuracy, This paper provides a new idea to solve Rayleigh-Plesset equation.
LEI Cheng,XIAO Shoune,LUO Shihui
Abstract: Energy-absorbing device is the key component to improve the crashworthiness of the rail vehicles.This paper introduces metal cutting technology into the field of passive safety protection of rail vehicles, andproposes the use of chip generation process to absorb the impact energy of the train, and this process is to treatas the energy-absorbing principle of new energy-absorbing device, T’he three-dimensional simulation for the en-ergy-absorbing process in metal-cutting way of metal thin-walled structure is caried out with explicit finite ele.ment, the inflience of tool rake angle on the absorption characteristics of thin-walled structures is analyzed,and energy-absorbing process of metal thin-walled structure in metal-cutting way is compared with the compres.sion. The results show that: the energy-absorbing process in metal-cutting way is a very ideal impact energyabsorption principle of rail vehicles.
WANG Jin-feng,BAO Yi,CHENG Yaosen,etc;
Abstract: There are more and more cable lines in urban power distribution network, as a result, the capaci-tive reactive power is sent back when the load is light, and the fault current is very large when one phase isshortened. This paper established a model of a whole cable line transformer substation by using the PSB ofMA’TLAB on the basis of the theoretical analysis and caiculation. Through the simulation and reasonable gelec.tion of the parameters, the two problem are solved synthetically, The simulation results have shown that thecapacitive current is reduced obviously at both the bus under no-Load and failure point. At the same time, theparameters of the required reactor when the length of cable line is different, which ean provide reference forengineering applications.
WANG Ruimin,LI Na
Abstract: The Capability Matrity Model® Integration ( CMMI® ) is applied to management, improvement andevaluation on software process. The aim of CMMl is the improvement on sotware process. The SPl( SoftwareProcess Improvement) can not be separated from projects monitoring and control. But the CMMl did not showus how to build up and practice it. When some software organizations want to build up their CMMl system,they met many difficulties in the process of monitoring and control. To find out an effective way of implemen.ting the project monitoring and control process area of CMMl, this paper make some research on the typicalweaknesses in the SPl and a template is put forward which is more available and customizable.
LI Xiaoyuan,LI Zhongwen,LV Wenjie
Abstract: The electroeardiogram ( ECG), temperature ( Temp) and respiration ( Resp) are all the most fun-damental bio-indicators of human body, These physiological signals are important for clinical research, sothese parameters of accurate monitoring and wireless transmission are greatly demanded in the clinieal diagno.sis. A novel file about the development and design of a physiological signal monitoring system in which physio.logical signal is transmitted by a wireless transmission modules - PTR2000 and it is processed by LabVlEW isintroduced . Finally , the effectiveness of physiological signal monitoring system is tested. The results show thatthe system based on LabVlEW presented in this paper can be used in the occasions of hospital wards, at homeand outside the hospital for real-time and continuous health monitoring for a long time for patients. lt also canmake comprehensive heaith evaluation and provide guidance for clinical diagnosis and family care.
MAO Xiaobo,ZHU Dongwei,CHEN Tiejun
Abstract: Object tracking based on color feature often fails in a complex background. To deal with this prob.lem , a particle filter object tracking approach is proposed in this paper based on the new histograms by the fu.sion of histograms of oriented grads and color, Color histogram is the global description of targets in color im.age, while histogram of oriented gradients contains some construction information. So they can complementeach other, Experimental results show that the proposed method is able to track the object stably, when one ofthe features loses discrimination ability for tracking. It is simple and suitable to be applied to deal with track.ing problemns in complex scene.
XIAO Mei,ZHANG Lei,KOU WenYu,etc;
Abstract: In order to reduce the impact of parameters on edge detection, we presenl a novel edge detection indigital images, The proposed method consists of an adaptive neural fuzzy inference system and a post-process.ing. We selected the 4 objective functions related to edge direction and gradient magnitude as the adaptive neural fuzzy inference system inputs. The input image and the target image used for training adaptive neural fuzzyinference system were synthesized by the computer. A post-processing procedure was applied to determinewhether the point was an edge point by using a fixed threshold compared with the adaptive neural fuzzy infer.ence system output value. The proposed edge detector is tested on popular images and also compared with popular edge detectors from the literature. Experimental results show that the proposed edge detector exhibitsmuch better performance than the competing operators and may efficiently be used for the detection of edges indigital images.
LI Chunwang,SUN Yuying,WU Yimin,etc;
Abstract: Traditional BACnet/Modbus gateway could realize data interchange only though data sharing, couldnot recognize Modbus devices directly under BACnet environment. The authors designed and developed a kindof BACnet/Modbus protocol converter based on routing function, By using it, the parsing and routing directingof Modbus device address could be realized in network layer, and BACnet datagram eneapsulating to Modbusdevice could be done in application layer, so that a Modbus device could be directly encapsulated into a BACnet device. The experimentation results show that the management and operation to a Modbus device could becompleted though BACnet software directly by using the protocol converter, and a higher data throughput wasobtained simultaneously.
FAN Gaojuan,HOU Yane,WANG Ruchuan
Abstract: Trapped positioning is the primary consideration in emergeney disaster response systems.(iven theadvantage that employing RSSl( Received signal strength indications) -based distanee estimation needs no ex.tra hardware, less communication cost as well as lower implementation complexity, we develop a RSSI-basedparameters correction emergency disaster response system.We propose a RSSl-based parameter correctionschema to tackle the problem of instability for RSSl information. We also give the system architecture of the e-mergency disaster response system, The system was implemented on VS2008 platorm, the experimental resultsshow that the system can obtain accurate information of the trapped persons. This system is very applicable tothe emergent disaster environment.
ZHANG Shixun,WANG Hailong,YANG Yang
Abstract: composites were prepared by roll-compaction and pressing sintering. That has ahigh bending strength (471 MPa) and fracture toughness (7.64 MPa * m1/2). The residual stress can be infavor of inereasing the thoughness of the laminated eomposite as the crack was blocked and deflected by stress.An uneven strain model is used to analyze the residual stress in the symmetric laminate composite. The resulpresented that the maximum tensile stress in the matrix layers is 64 MPa, the maximum compressive stress inthe Mo interlayer is 320 MPa. And the shear stress between the matrix layer and interlayer is 1. 149 MPa. Theresidual stress was affected by the thick ratio between matrix layer and interface layer.
CHEN Juliang,ZHANG Huasen,LIU Guoji
Abstract: The kinetics for hydrogenation of adiponitrile were studied with Raney nickel as catalyst in a a high-pressure batch reactor. Under the condition of no inside and outside diffusion, the coneentration of adiponitrile , aminocaproic nitrile and hexamethylenediamine versus time over the Raney -- Ni catalyst were measured.The kinetic parameters of catalytic hydrogenation of adiponitrile to hexamethylenediamine such as reaction or.der, pre - exponential factor and activated energy in each step were obtained. The results show that, when thetemperature kept at 328 ~358K and pressure kept at 2 .3. 5MPa, the order of adiponitrile hydrogenation toadiponitrile was 1 , while to hydrogen pressure was l.4. The intermediate aminocaproic nitrile was hydrogenated to hexamethylene diamine, the reaction order to aminocaproic nitrile was 0, to hydrogen pressure was l. 3Based on these results, the kinetic equations of adiponitrile hydrogenation to hexamethylenediamine in eachstep were proposed, They are in consistence with the experimental data.
ZOU Ruyi,XU Zhilong,YE Yong,etc;
Abstract: Abstraet: An unexpected compound 1 ,2-bis( ( 4-( 2-bromoethoxy) naphthalen-l-yl) oxy)ethane was synthe.sized by the Schlenk line skill with 1 ,4-naphthoquinone as slarting reactant and its structure was characterizedby 1H NMR and 13C NMR based on its DEPT and HSOC spectra. Then the diimidazolium as a novel precursorof N-heterocyelie carbene was synthesized by the title compound with 1-methylimidazole and characterized byH NMR and ESl-MS , which further confirmed the title compound structure.
LI lilin,WANG Zhong,XU Guangju,etc;
Abstract: The reflected shock using CHEMKIN model to simulate biodiesel combustion, analyze the effects ofdifferent equivalence ratio and EGR rate on the biodiesel soot precursor polyeyelic aromatic hydrocarbons onbenzene , naphthalene, phenanthrene and pyrene. The results showed that; benzene, naphthalene, phenan.threne, pyrene mole fraction decreased with the increase of equivalence ratio form 1. 0 , 1. 7to 2. 1 , inhibitedthe formation of polyeyclic aromatic hydrocarbons, decreased the soot ,ECR rate of 0 ,0 ,5% , 10% , 20% and40% benzene curves almost coincide in the prophase, 40% EGR rate higher after 4 us, naphthalene, phe.nanthrene , pyrene increased with the increase of EGR rate.
ZHOU Cairong,YU Xin,YANG Yonggao,etc;
Abstract: DBD( Dielectrie Barrier Discharge ) plasma was used to sludy the hydrogenation reaction of benzeneby the CTp -2000K plasma power supply at atmospheric pressure. The discharge voltage, residence time andproportion of gas material were changed respectively to establish the optimized conditions. The optimized con-ditons were found to be discharge vollagel4 kV, residence time 12s, gas ratio of Vw/V,, =2: 1. The effect ofplasma - catalytic synergy on the raction was investigated. Compared with the result of non - existent catalyst,the percent conversion of benzene inereased from 7896 to greater than 90% , and the selectivity of cyclohexanecould reach 70% . The prepared catalyst was characterized by BH]and EMS ,respectively. The results indi-cate that the catalyst handled by plasma, the specific surface area increased from 13.72 m3· g-1 to 19.08 m3g-1, and the hole volume increased from 76.81 x10-3cm3·g-1 to 107.7 x 10-3cm3.g-1, respectively.SEM analysis shows the the surface grain size distribution on Ni/Si02 catalyst is uniform for 8 nm, the actionelement Ni of catalyst is up to 32% at outside surface
WAN Yazhen,ZHANG Wenhui,FAN Xiaolei,etc;
Abstract: In this paper, the electrocatalytie degradation properties of phenol on β-PbO,-SPE compositemembrane electrode in different media were investigated with cyclic voltammetry ( CV) method. The CV experimental results show that, only in the alkali and intermediate media, the phenol can be directly destroyedand the degradation power in alkali media goes beyond to intermediate media. The electron transfer coefficientsare calculated which is 0. 127 in alkali media, and is 0. 156 in intermediate media. The CV curves in differentscanning rates show that the degradation reactions were controlled by diffuse processes.
CHEN Zhiqiang,NIU Tianye,LI Hongbo,etc;
Abstract: There are plenty of intrinsic cation states on the surlace of nano-semiconductor crystals.When theerystals contact the transformer oil,surface states that can capture electrons easily are formed. In this paper TiO2 nano-powders with different surface modifications have been used to improve the property of transformeroil ( Kelamayi 25 ). The modifcation effeets of nano-power’s on insulating property of transformer oils havebeen investigated, And the modifying effects of TiO2 nano-powder with different concentrations on transformeroil have been studied. The breakdown property tests and fitting results show that TiO2 nano-powder can improve the breakdown properties of transformer oil and within some concentrations,the higher the concentrationof TiO2 nano-powder , the better the power frequeney insulating property of modifying transformer oil. Besides,The modifying agents play a key role in the dispensability of Ti0, nan-powder in the transformer oil. With theincreasing of nonpolar segment in the modifying agent, the breakdown property of the modified oils gets moreenhancements.
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