Volume 35,Issue 10,2012 Table of Contents

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  • 1  The optimization for vibration comfort of commercial vehicle cab based on road test
    HE Yansong ZHANG Junfeng Xu Zhongming ZENG Jia
    2012, 35(10):1-8. DOI: 10.11835/j.issn.1000-582X.2012.10.001
    [Abstract](2322) [HTML](0) [PDF 9.45 M](1257)
    Abstract:
    The vibration comfort of commercial vehicle is improved in two ways where the data for the road-test are used as excitation and validation signals. The cab structure is optimized in HYPERMESH.At different speeds,acceleration RMS of the driver’s seat is reduced by 6% on average compared with the previous structure in ADAMS. In terms of the cab suspension,a multi-body dynamics model based on flexible cab is built. Taking the acceleration RMS as the evaluation target,the orthogonal test for optimizing the stiffness and damping of the suspension is conducted in the frequency domain. The different dynamic deflections are compared in time domain..At different speeds,acceleration RMS of the driver's seat is reduced by 10% on average after optimization of the cab suspension,dynamic deflection is reduced by 21% on average.
    2  Finite element model of coupled systems for vibration reduction plates with smart constrained layer damping
    Cao Youqiang Deng Zhaoxiang Wang Pan Liu Huijie
    2012, 35(10):9-16. DOI: 10.11835/j.issn.1000-582X.2012.10.002
    [Abstract](2674) [HTML](0) [PDF 7.68 M](1360)
    Abstract:
    Considering the relationships of coupling movement and compatible displacement among bonding layer, piezoelectric layer, damping layer, and base structure, a finite element dynamic model of coupled systems for vibration reduction plates is established. The model combined with piezoelectric theory, finite element theory and ADF model of viscoelastic damping material can be suitable for vibration model of complex SCLD structure. The dynamics parameters for clamped-clamped steel plate with partially treated smart constrained layer damping are obtained by theoretical calculation, ANSYS modal analysis and modal experiment. The results show that theoretical values are closer to the test results and ANSYS analysis, and the methods proposed is more accurate and effective.
    3  The study on EMI principle and suppression method of vehicle ignition system
    YANG Yongming SU Chengjun AN Zongyu WANG Quandi
    2012, 35(10):17-23. DOI: 10.11835/j.issn.1000-582X.2012.10.003
    [Abstract](2516) [HTML](0) [PDF 9.22 M](1362)
    Abstract:
    Vehicle ignition system is the main electromagnetic interference source. Electromagnetic radiation produced by ignition system will produce the interference to electromagnetic environment around. It is necessary to study the electromagnetic interference (EMI) principle, noise paths and suppression method. We analyze the electromagnetic interference principle of ignition system, and harness trouble-shooting related to electromagnetic interference is also tested. Results show that the spark discharge between spark plug electrodes is the main interference source in ignition system. Then, the paths of conducted interference and the reason of radiated emission are discussed in detail. Finally, two kinds of power supply cord EMI filters are designed and implemented on the basis of analysis results. Experimental results indicate that the filter can reduce the noise of power-wire in broadband range. Simultaneously, the radiation emission performance from power wire is also reduced observably. The proposed mixing filter has been demonstrated in this paper to perform satisfactorily with excellent effectiveness in suppression of conducted EMI from 10 MHz to 110 MHz, and the object car can also pass the EMC standard tests.
    4  Effects of rolling lubrication on flange lateral spread of H-beam
    ZHAO Jingyun ZANG Yong
    2012, 35(10):24-29. DOI: 10.11835/j.issn.1000-582X.2012.10.004
    [Abstract](1678) [HTML](0) [PDF 6.73 M](1332)
    Abstract:
    Although rolling lubrication can decrease rolling forces and energy consumption, it also causes defects such as uneven flange lateral spread and web eccentricity during H-beam rolling process. To solve the problem caused by lubrication, finite element models of H-beam universal rolling were established. The different friction conditions of the contact surface between the rollers and work piece were simulated individually. The mechanism of rolling lubrication impacting on flange spread was studied, and the law of flange lateral spread was gained by analyzing the factors such as friction distribution and metal flow in different situations. Analytical results show that lubrication in rolling process can effectively decrease rolling forces and energy consumption. In the condition that technological parameters except friction are fixed, the flange lateral spread decreases in a linear way as the friction coefficient between flange and roller increases, and the flange lateral spread is more sensitive to the friction of flange's the inner side. Design of lubrication process should take full account of the sensitiveness differences of flange lateral spread to the lubrication conditions of different parts of roller surface.
    5  Experimental analysis of the abrasive belt follow-up grinding of Zirconium-4 alloys tubes and pipes
    HUANG Yun ZHANG Lei HUANG Zhi GUO Qiang
    2012, 35(10):30-37. DOI: 10.11835/j.issn.1000-582X.2012.10.005
    [Abstract](2908) [HTML](0) [PDF 10.16 M](8881)
    Abstract:
    Abrasive belt grinding experiments of Zr-4 nuclear power tube are carried out by using three different abrasive belts with same size, and the interactive generating mechanism between abrasive and workpiece is analyzed, the main factors of material removal rate and surface roughness of Zr-4 alloys are obtained. With the help of the advanced test facilities, the abrasive grain abrasion and surface topography of the workpiece are observed. The metallographic structure and microhardness of the layer of burnt surface during Zr-4 alloys Grinding are analyzed. Some conclusions are given as follows: the material removal rate and surface roughness are mainly affected by the factors of belt speed, grinding pressure, hardness of the contact wheel and abrasive type, of which, the belt speed is the strongest factor. The adhesion wear of the Zirconium corundum and aluminium oxide abrasive grit is more serious, the most important wear form of silicon carbide is abrasion wear. With the onset of grinding burn, the mechanical properties of Zr-4 alloys are deteriorated obviously. The results provide a theoretical and experimental basis for technical optimization in the grinding of Zr-4 alloys with efficiency and high quality.
    6  Fatigue monitoring of metallic structures by wireless smart sensor networks
    CUI Dingyu B F Spencer Jr XIN Kegui LIU Yufei
    2012, 35(10):38-43. DOI: 10.11835/j.issn.1000-582X.2012.10.006
    [Abstract](1939) [HTML](0) [PDF 7.17 M](1285)
    Abstract:
    Recent advanced sensor technology has enabled wireless smart sensor network (WSSN) for structural health monitoring (SHM). Because of many attractive features such as wireless communication, battery powered, on board computation, and low cost, the WSSN makes the dense array of sensors feasible for engineering practice.In this study, a method for fatigue life monitoring using wireless smart sensor networks is explored by implementing Rainflow cycle counting algorithm in the sensor network, which extracts the loading features including the number of each load cycles, amplitude and mean of strain.Instead of sending back raw strain data to basestation, only the onboard processed histogram of the strain data is transmitted, which tremendously reduces the amount of data and the associated energy consumption in the wireless smart sensor networks.In addition, the feasibility of the method is experimentally verified through lab-scale tests.
    7  The research of bearing capacity for double-angle composited cross-section member of UHV transmission tower
    Li Zhengliang Sun bo Yu Zhou Yang Longyu Yu Dengke
    2012, 35(10):44-50. DOI: 10.11835/j.issn.1000-582X.2012.10.007
    [Abstract](1776) [HTML](0) [PDF 8.35 M](1395)
    Abstract:
    With the rapid development of power industry in China,the traditional single angle steel members of the transmission tower cannot meet the requirements of high voltage, multi-loop, high-load and so on. By doing experiments with double-angle cruciform section, whose specification are L160×12,L160×14,L160×16, we analyze the ultimate bearing capacity of main components which constitute UHV transmission tower. Meanwhile, we use the FEM to deal with the influence of the parameters including different ratios of slenderness, different number and location of fill plate, etc. The calculation results are comperred with each other based on some general codes. The results show that, for some test pieces with certain ratios of width to thickness, other codes and Eurocode 3 code are not safe, but ASCE10-97 code is completely unsafety. So we propose the modifier formulas of calculated length. The best way of arranging plates is uniform layout and the best space between plates is existed.
    8  Aerostatic stability analysis of long span half-through arch bridges
    XIONG Hui YAN Zhitao LI Zhengying DENG Nuan
    2012, 35(10):51-56. DOI: 10.11835/j.issn.1000-582X.2012.10.008
    [Abstract](2348) [HTML](0) [PDF 7.31 M](1316)
    Abstract:
    The main arch of a long-span arch bridge is a compression member. The static wind loads on the bridge not only causes changes of dynamic characters, but also leads the structure to collapse or buckling. Especially, when the arch bridge has longer span and less lateral braces,its stability is much different from the long span cable-stayed bridges and suspension bridges. This paper takes Chongqing Caiyuanba Yangzi River Bridge as a typical example and conducted the wind section tunnel tests. The displacement response of the bridge is obtained and its yield and static stability mechanism under static wind is analyzed. The results show that those factors, such as initial attack angle of the static wind, material yield strength and the static forces coefficients, have great effects on the aerostatics stability of a long span half-through arch bridge.
    9  Texture image retrieval using double density dual tree complex wavelet RH model
    SHANG Zhaowei WANG Jie LI Wenlong HU Shengxiong
    2012, 35(10):57-62. DOI: 10.11835/j.issn.1000-582X.2012.10.009
    [Abstract](1841) [HTML](0) [PDF 7.53 M](1197)
    Abstract:
    For using smooth probability density function to retrieve wavelet coefficient histogram and coefficient module histogram, parameter estimation is complicated, which results in hard to retrieve the texture features effectively. A texture image retrieval method using double density dual tree complex wavelet Refined Histogram(RH) model is proposed. By analyzing the principle of double density dual tree complex wavelet transform (DD-DT CWT) and the inherent relationship between the nonuniform quantizer and RH model, the RH model is extended to retrieve the DD-DT CWT coefficient and the coefficient histogram feature. The RH is used to model the magnitude of the DD-DT CWT. The RH parameters for all magnitude of complex coefficients forms the signature of an image. Image similarity measurement is accomplished by using the Kullback-Leibler divergences . The proposed method combines the advantages of the RH model and the shift-invariant DD-DT CWT. The experiment results show that the proposed methods yields higher retrieval rate than using the General Gaussian Density(GGD) model to fit with the real part or imaginary part of coefficients, and is better than using the Gamma PDF to fit with the magnitude of coefficients.
    10  Image denoising based on adaptive graph regularization
    LIU Guojin ZENG Xiaoping LIU Yi
    2012, 35(10):63-68. DOI: 10.11835/j.issn.1000-582X.2012.10.010
    [Abstract](1695) [HTML](0) [PDF 7.63 M](1540)
    Abstract:
    Adaptive regularization can select different parameters based on the features of local areas in an image, which can differentiate the edges and noise in an image flexibly. An adaptive graph regularization is proposed based on graph spectral theory and adaptive regularization, which uses the Non local means to generate the weighting function of graph. The adaptive graph regularization equation is used to filter the noisy image. Simulation results show that the proposed method can effectively remove the noise and is superior to other graph theory based partial differential equation methods.
    11  Study on CO2 removal by monoethanolamine/polyamine aqueous
    DU Yungui LIU Tao GU Min LU Yiyu XIAN Xuefu
    2012, 35(10):69-75. DOI: 10.11835/j.issn.1000-582X.2012.10.011
    [Abstract](2057) [HTML](0) [PDF 8.27 M](1195)
    Abstract:
    Aqueous monoethanolamine (MEA) is the mostly used absorbent for removing carbon dioxide (CO2) from fuel gas in the industry. Improving the performances of aqueous MEA is the key for the effective CO2 removal. The absorption, regeneration performances and corrosion properties of MEA and its four blends with polyamines (MEA/polyamines) at the same concentration are studied. The polyamines, including N-(2-hydroxyethyl) ethylenediamine (AEEA), piperazine (PZ), diethylenetriamine (DETA) and triethylenetetramine (TETA), are considered. The results show that the absorption and regeneration capacity of four kind blends of MEA/polyamine are much better than that of MEA when the content of polyamines are low. The corrosion rate of MEA/polyamine is low than that of MEA. However, with the increase of polyamines content in blends, the regeneration rates of the blends decrease. It is concluded that MEA/polyamine with suitable polyamine content is a high efficiency absorption solvent comparing with MEA. Among the four blends of MEA/polyamine, the performance of MEA/DETA and MEA/TETA are the best.
    12  Nalytical study on crack magnetic flux leakage for ferromagnetic component and detection system based on geomagnetic field
    LIAO Changrong LIAO Zheng HAN Liang WANG Binbo SHI Xiangcong XIE Yunshan
    2012, 35(10):76-84. DOI: 10.11835/j.issn.1000-582X.2012.10.012
    [Abstract](1645) [HTML](0) [PDF 12.85 M](1226)
    Abstract:
    Based on technical aspects of ferromagnetic components crack damage detection methods and instruments applications, this paper establishes a the magnetic flux leakage analysis model for V-Cracks to get the theoretical expressions for any probe point of flat ferromagnetic component surface. We use MATLAB software programming to do a comprehensive simulation, and obtain the relation curve between magnetic flux leakage normal component Hy and crack opening width, the relation curve between magnetic flux leakage normal component Hy and crack depth, the relation curve between magnetic flux leakage normal component Hy and crack length are obtained, crack magnetic flux leakage distribution characters: normal component of Hy with zero-crossing, maximum value of tangential component Hx, and tangential component Hz with tip zero-crossing. According to the leakage magnetic characteristics obtained underby the theoretical analysis, the array type detection device and test platform are designed and fabricated, and then the plate-type ferromagnetic component with V-Cracks is detected. The experimental results show that: there is a good agreement between the three-dimensional magnetic flux leakage obtained from thesis theoretical analysis and the test results, to a certain degree the magnetic flux leakage model has directive significance for the prediction and analysis of crack parameters, and the test device be developed according to the magnetic flux leakage model is able to detect cracks in ferromagnetic components.
    13  PAHs formation mechanism during Combustion Process of Diesel Engines
    WANG Feng ZHENG Zhaolei HE Zuwei
    2012, 35(10):85-92. DOI: 10.11835/j.issn.1000-582X.2012.10.013
    [Abstract](2374) [HTML](0) [PDF 9.49 M](1355)
    Abstract:
    Based on the diesel surrogate fuel (n-heptane and toluene), we develop a new kinetic mechanism of diesel surrogate fuel included polycyclic aromatic hydrocarbon (PAHs) formation and growth of up to five aromatic rings. The new mechanism included 153 species and 697 reactions. We compare it with various experimental data available in the literature including shock tube, n-heptane premixed flames and homogeneous charge compression ignition(HCCI) engine, and the results show the good performance for HCCI combustion prediction by this new mechanism. The presented mechanism can be used as the basis for further reductions and applied the combustion and emission simulation by coupling chemical reaction kinetics model with computational fluid dynamics model in internal combustion engines.
    14  Fast stabilization algorithm of dynamic scene video with multiple foreground objects
    HE Kai MU Congchong YUAN Zhongwen HE Hailong ZOU Gang
    2012, 35(10):93-98. DOI: 10.11835/j.issn.1000-582X.2012.10.014
    [Abstract](1629) [HTML](0) [PDF 6.94 M](1762)
    Abstract:
    In order to improve the stabilization effect of dynamic scene video sequences with multiple moving foreground objects, a new method based on block absolute difference is proposed to extract the foreground objects automatically. Based on extracting the moving objects, the background blocks are selected to estimate the motion parameters with the defined threshold, so the background blocks for estimating motion parameters are greatly reduced. For moving scene with multiple moving foreground objects, due to the reduction of the time of extracting moving objects, the simulation results shown that the running time of the proposed method is reduced effectively, the stabilization effect is improved, and more ideal effect is realized compared with the traditional method.
    15  The fall point arithmetic of rocket wreckage adopting atmosphere resistance modification
    He Jingjiang Wei Zhidong Dong Jihui Wei Shanbi
    2012, 35(10):99-103. DOI: 10.11835/j.issn.1000-582X.2012.10.015
    [Abstract](2211) [HTML](0) [PDF 4.57 M](1448)
    Abstract:
    For the fall point calculation problem of Rocket Wreckage,the kinetic traits of rocket wreckage is analyzed, and the influence of the atmosphere resistance to wreckage fall point is studied mainly. The fall point algorithm of rocket wreckage adopting atmosphere resistance modification is proposed. Comparing with the traditional fall point algorithm, in the proposed method, the influence of layered atmosphere density of fall-point area is considered properly, and the air resistance coefficient is estimated according to the air dynamic equation of fall process, the integral method is adopted to get the moving track of the rocket wreckageand the final fall point. The effectiveness of the algorithm is validated by analyzing the fall points of the first stair of the rocket in four tasks corresponding to four types of rockets.
    16  Numerical simulation of desulfurization characteristics in CFB flue gas with bypass
    TANG Qiang HOU Shifeng ZHANG Xiaoqin
    2012, 35(10):104-108. DOI: 10.11835/j.issn.1000-582X.2012.10.016
    [Abstract](1535) [HTML](0) [PDF 5.61 M](1115)
    Abstract:
    This paper uses the standard k-ε model, DPM, Species Transport and Finite-Rate Chemistry model to simulate momentum, energy and composition equations of a new CFB desulfurization tower with gas bypass. The numerical simulation results agree well with the experimental results. The characteristics of desulfurization and flow resistance of two desulfurization towers are analyzed by numerical simulation, and the influence of SO2 concentration to desulfurization efficiency of bypassing desulfurization tower is also analyzed. The results show that both desulfurization and flow resistance characteristics of bypassing desulfurization tower are better than those of non-bypassing desulfurization tower. The desulfurization efficiency of bypassing desulfurization tower decreases with the increase of SO2 concentration, the desulfurization efficiency increases with the increase of the relative humidity of bypassing desulfurization tower.
    17  Multifocus image fusion scheme based on feature contrast in lifting stationary wavelet domain
    LI Zhaofei CHAI Yi GUO Maoyun LI Huafeng
    2012, 35(10):109-116. DOI: 10.11835/j.issn.1000-582X.2012.10.017
    [Abstract](1874) [HTML](0) [PDF 9.44 M](1418)
    Abstract:
    A novel multifocus image fusion method based on lifting stationary wavelet transform (LSWT) is proposed. The selection principles, namely fusion rules of different subband coefficients, are discussed in detail. Local feature contrast is presented according to the human vision system (HVS), which is highly sensitive to the local image contrast level. Then, the fusion rule for the low-frequency subband coefficients fusion is introduced. To choose the high frequency subband coefficients, another local feature contrast is developed according to the human vision which is often sensitive to edges and directional features, but insensitive to real luminance at independent positions. Then, a novel fusion rule is proposed for fusion of the high frequency subband coefficients. Experimental results demonstrate that the proposed image fusion method is effective and can provide better performance in fusing multifocus images than the traditional contrast-based image fusion algorithms in term of informal visual inspection and objective criteria in multi-focus image fusion.
    18  Modeling and control of An LCL bi-directional inductive power transfer system
    LI Yanling SUN Yue DAI Xin ZHOU Jikun
    2012, 35(10):117-123. DOI: 10.11835/j.issn.1000-582X.2012.10.018
    [Abstract](1875) [HTML](0) [PDF 8.54 M](1169)
    Abstract:
    Since there exist high-frequency switching networks and complicated operating modes in bi-directional inductive power transfer (IPT) system, it is easy to result in high harmonics and EMI interference. An LCL filter network is introduced to effectively filter out the unwanted harmonics in track current and reduce EMI interference. Based on a mathematical model of the power transmission established by complex analysis of the AC variables, under the condition of maximum transmission efficiency, the phase angle differences between the primary input voltage and secondary output voltage U·so are ±90° and the energy is respectively transferred in forward or backward direction. Moreover, the power magnitude can be controlled by adjusting the modulus of U·pi and U·so. In addition, to keep the track current constant, different phase-shifting control strategies are designed in the primary and secondary parts. Simulation and experimental results show that these strategies can not only adjust track current to keep constant but also dynamically change the direction and magnitude of power transmission according to the working conditions and actual needs of the system load to improve the system operating efficiency.
    19  A new type of prestressed concrete hollow girder design for overcoming the typical diseases
    YUAN Aimin ZHOU Yuanhua DAI Hang SUN Dasong
    2012, 35(10):124-129. DOI: 10.11835/j.issn.1000-582X.2012.10.019
    [Abstract](1551) [HTML](0) [PDF 6.86 M](1477)
    Abstract:
    This paper proposes a new type of prestressed concrete hollow girder based on the summaries of the current studies on longitudinal cracks and hinge cracks. The match prefabricated method is used with shear key at interface to solve the problem of hingle cracks, and the two-way prestressing strand techniques are used to assure the longitudinal load-bearing capacity and to prevent the emergence of longitudinal cracks because of pressure existing at the match interface. In order to reduce the temperature difference between the internal and external of the prestressed concrete hollow girder, drilling holes are carried out at the bottom slab of girder every distance. To ensure the adhesive effect between the girder and deck pavement, we designed grooves at the top slab of girders. The finite element analysis results of a design example show that the pressure stress of bottom slab of girder is about 2.58 MPa and 0.16 MPa, which are effective to avoid the appearance of longitudinal cracks and hinge cracks.
    20  The compensation method for the random time-delay of the feedbackchannel and the forward channel in the networked control system
    FU Wei YANG Xianyi LIU Guoquan
    2012, 35(10):130-135. DOI: 10.11835/j.issn.1000-582X.2012.10.020
    [Abstract](1795) [HTML](0) [PDF 7.40 M](1432)
    Abstract:
    An improved predictive control method is presented to compensate the random time delay in the networked control system. The feedback time delay is compensated by predictive controller based on softened increment input strategy. The forward time delay is unknown for controller, so an extra feedback loop is added to compensate the delay by estimating the error between the actual control signal effected on plant and the output of controller in historical moment. For the controlled system with unknown or slowly varying parameters, the networked feedback correction algorithm is discussed based on a modified recursive least-squares identi cation algorithm. The system stability is analyzed and the simulation results show that the time delay in the networked control system can be accurately compensated. The excellent network performance is ensured with this strategy.
    21  Continues software reliability demonstration testing scheme with decreasing function
    WANG Xuecheng LU Minyan LI Haifeng YANG Risheng
    2012, 35(10):136-143. DOI: 10.11835/j.issn.1000-582X.2012.10.021
    [Abstract](1711) [HTML](0) [PDF 7.26 M](1263)
    Abstract:
    The required testing duration of software reliability demonstration testing (SRDT) for the continuous safety-critical software is generally too long to endure. To solve this problem, a new continuous Bayesian-based SRDT scheme (CBSDF) for the safety-critical software is proposed by using the decreasing function method with the prior information. The representative decreasing function of the continuous reliability index (such as the failure rate) is selected to construct the prior distribution density function (PDDF). Then, the estimation values of the hyper-parameters of PDDF are calculated according to the prior information (i.e. the failure data collected in reliability growth testing) to obtain the posterior distribution and the detailed form of CBSDF. By selecting two failure data-sets as the source of prior information, the proposed CBSDF is compared with two existing Bayesian-based schemes (i.e. CBS1 without prior information and CBS2 with prior information). The experimental results show that with the same given reliability index, the proposed CBSDF is more effective than CBS1 and CBS2 by significantly decreasing the required testing time of SRDT and more suitable for the safety-critical software with high reliability.
    22  Numerical Simulation of Thermomagnetic Convection of Air in a Porous Cubic Enclosure
    JIANG Changwei LI Hesong CHEN Donglin SHI Er ZHU Xianfeng LI Mao
    2012, 35(10):144-151. DOI: 10.11835/j.issn.1000-582X.2012.10.022
    [Abstract](1429) [HTML](0) [PDF 9.81 M](1081)
    Abstract:
    This paper numerically investigates thermomagnetic convection of air in a porous cubic enclosure with a electric coil inclined around the X axis under microgravity environment. The porous cubic enclosure is heated isothermally from left-hand side vertical wall and cooled isothermally from opposing wall while the other four walls are thermally insulated. The governing equations in primitive variables are discretized by the finite-volume method and solved by the SIMPLE algorithm. Computations were performed for a range of the Rayleigh number from 10 4to 10 5, the inclination angle of coil xeuler from 0° to 90°, magnetic force parameter γ from 0 to 200 and Danumber from 5×10 -4to 5×10 -3. The results show that the overall heat transfer is enhanced gradually with the increase of γ number,Ra number and Da number. The resulted convection is symmetrical in terms of the angle at xeuler=45 ° when the range of inclination angle is from 0 ° to 90 °.
    23  Effect on the performance of piston cam enginewith the parameters of valve mechanism
    XU Qinchao WANG Shuzong LIAN Yongqing
    2012, 35(10):152-158. DOI: 10.11835/j.issn.1000-582X.2012.10.023
    [Abstract](1719) [HTML](0) [PDF 9.18 M](1200)
    Abstract:
    In order to investigate the effect on the performance of piston cam engine by the valve parameters, the instantaneous state analysis method is used to model the thermal process in cylinder and that is analyzed through computer simulation. The researching results indicate that the aperture of the air hole have little effect on performance of the piston cam engine when it is greater than a certain value; economy can be increased by decreasing intake angle on the premise of power need; power can be increased by decreasing the pressure of cylinder to back pressure at time of piston begin to get back; the forehead intake angle and compress angle for optimum power and economy can be get by comparing to different simulation results.
    24  The edge element method in the forward problem of magnetic inductiontomography with homogeneous sinusoidal magnetic excitation
    HE Wei SONG Xiaodong ZHANG Xiaoyong FAN Zhaoyong LUO Haijun XU Zheng
    2012, 35(10):159-164. DOI: 10.11835/j.issn.1000-582X.2012.10.024
    [Abstract](1619) [HTML](0) [PDF 6.70 M](1289)
    Abstract:
    The edge finite element method and the imaging visualization have been studied in the forward problem of magnetic induction tomography MIT with homogeneous sinusoidal magnetic excitation. The definite equations of the forward problem were established using the electric field intensity as the vector variable. The edge FE method for solving the definite equations was introduced in detail and realized as the MATLAB program. In order to realize the visualization of MIT in imaging the intracranial hemorrhage, a real human brain finite element model was created with the human head MRI data. On the basis of this model, we realized the 3D visualization of MIT imaging in MATLAB. The research results demonstrated the validity of the definite equations and the edge FE method in calculating the forward problem. And the 3D visualization of MIT imaging with real human brain model established a foundation for the application study of MIT in imaging intracranial hemorrhage.

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