2009 Vol.15

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Some Remarks on the Multiplicative Decomposition F＝FeFp in Finite Elasto-Plasticity SUN Bo-hua1,YE Zhi-ming2 Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 1-7.   Abstract （2233）      PDF（pc） （839KB）（971）       Knowledge map    Save Based on the work of Stumpf and Badur (1990) some problems related with the multiplicative decomposition F＝FeFp in finite elasto-plasticity have been investigated in detail. It is pointed out that there is no chance to supply an additional independent constitutive equation for plastic and/or elastoplastic spin since it can be represented, in general,by elastic and plastic stretches, as well as elastic and plastic deformation rates. It is especially for the case of rigid-finite plastic deformation suitable for metallic materials, the explicit representation of plastic spin, objective rate of back-stress and its relation with the Zaremba-Jaumann rate. Finally, a suitable way is pointed out that can supply an additional constitutive equation to plastic spin is the use of additive decomposition of elastoplastic deformation rates. Related Articles | Metrics | Comments（0）

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Equivalence of Lp Projection Inequality and Lp Centroid Inequality YU Zhi-gang，YUAN Jun，LENG Gang-song Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 8-10.   Abstract （2208）      PDF（pc） （270KB）（899）       Knowledge map    Save Petty’s projection inequality and Busemann-Petty centroid inequality are the basic inequalities in the classical Brunn-Minkowshi theory. In the recent studies, Lutwak, Yang and Zhang generalized the above two inequalities into the circumstances of Lp  Brunn-Minkowshi. The purpose of the present paper is to show equivalence of the Lp  Petty projection inequality and the Lp Busemann-Petty centroid inequality. Related Articles | Metrics | Comments（0）

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Finite Groups with Every Non-abelian Subgroup Being Subnormal LUO Xiao-liang,GUO Xiu-yun Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 11-13.   Abstract （2299）      PDF（pc） （391KB）（943）       Knowledge map    Save In this paper， the finite non-nilpotent group with every non-abelian subgroup being subnormal  is investigated.It’s shown that such groups are solvable, and then give a necessary and sufficient condition and some structures for this kind of groups by taking into account the Sylow subgroups. As an application, the supersolvable group with the above property is discussed. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Distance between Unit Balls in lnp-Space and Its Application MA Dan,HE Bin-wu Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 14-16.   Abstract （2523）      PDF（pc） （296KB）（925）       Knowledge map    Save The Banach-Mazur distance, defined by homothetic transformation, between two different unit balls in lnp-space is shown with optimization calculation. Compared to the Banach-Mazur distance, it shows distance between convex bodies without any rotation. The result is applied to estimate the Gaussian measure of unit balls in the lnp-space. Related Articles | Metrics | Comments（0）

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Conditions for Two Types of Ellipsoids of Parallelotope Being Ball LIU Xu-fei,WANG Wei,LENG Gang-song Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 17-19.   Abstract （2215）      PDF（pc） （297KB）（902）       Knowledge map    Save John ellipsoid and new ellipsoid are two types of important ellipsoids in convex bodies. In this paper, a necessary and sufficient condition for each of the two types of ellipsoids of the parallelotope being a ball is given. Related Articles | Metrics | Comments（0）

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A Model of Growing and Navigating Networks DU Li-juan,SHI Ding-hua,CHEN Qian Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 20-25.   Abstract （2194）      PDF（pc） （813KB）（998）       Knowledge map    Save There are three important structural features in complex networks: small-world effect, scale-free property and network’s navigability. Typical models reflecting these features, respectively, are the Watts-Strogatz’s model, the Barabási-Albert’s model and the Kleinberg’s model. Based on the typical models, a new model of growing and navigable networks is proposed, with the generated networks possessing all these features simultaneously. The results of navigation obtained by using a greedy algorithm on networks of the model are similar to, or even better than, that of the Kleinberg’s model. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Mesh Free Difference Method Applied to Flows around 2-D Airfoil YE Zhi-qiang,LIU Gao-lian,CHEN Bo Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 26-31.   Abstract （1983）      PDF（pc） （569KB）（1013）       Knowledge map    Save According to the mesh-free method based on local Cartesian frame proposed by the author, partial derivatives at every node and natural boundary conditions are constructed by using the total directional derivative formulas. No mesh element is needed at all. Therefore it is very simple both theoretically and computationally. The method is tested with a numerical example of fluid flow. A reliable solution is obtained with high accuracy and efficiency. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Optimization of Pumping Station with Simulated Annealing and Genetic Algorithm WEI Xin-hua,GUO Jia-hong Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 32-36.   Abstract （2158）      PDF（pc） （620KB）（1006）       Knowledge map    Save To cope with the problem of low efficiency of pump station due to unreasonable combination of the pumps, a mathematic model for optimizing the combination is proposed leading to minimal power consumption. The constraining conditions in the model are the pump head, total water supply and rotation speed of the pumps. A simulated annealinggenetic algorithm is used to determine the number of pumps in operation, the rotation speed and the flow rate of each pump when the pump station is in an optimal state. The infeasibility degree is introduced into the algorithm to choose a suitable result from every population and to balance the demand between the target function and the constraining conditions. The result of an example shows feasibility of the present algorithm for pump station optimization. Related Articles | Metrics | Comments（0） Cited: Baidu(9)

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Deviation of Light Path in Born-regulated Gravity in Four Dimension ZHOU Jian-hua,FANG Wei,LU Hui-qing Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 37-41.   Abstract （2114）      PDF（pc） （528KB）（903）       Knowledge map    Save Deviation of light from its straight path is caused by the presence of massive objects, i.e., the presence of gravitational field according to the general theory of relativity. It is shown that the low energy effective field theory on D-branes is of Born-regulated gravity theories. In this work a Born-regulated type gravitational field is postulated. According to the space time metric in the Born-regulated gravity theory, An explicit representation of the angular deviation of light path is derived. A Born-regulated type theory of gravitational field is postulated, and an explicit representation of the angular deviation of light path is derived, Δφ≈4Mrmin-4Mrmin49k2βr6min. Clearly, the result shows that β→0 and k→0, Δφ→4Mrmin which is just the result from the Einstein’s general relativity theory. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Mixed-Signal SoC Verification Using NanoSim-VCS HU Yue-li,JING Wen-yi,XUAN Xiang-guang Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 42-46.   Abstract （2361）      PDF（pc） （638KB）（988）       Knowledge map    Save Complex full-chip system verification and interface nodes analysis between analog and digital circuit are a bottle-neck in mixed-signal system design. In this paper， a mixed-signal verification method based on NanoSimVCS is proposed, which is used to verify SHU-MV06, a mixed-signal design including Verilog and SPICE. This method provides efficient simulation with high accuracy and speed by performing speed-versus-accuracy tradeoffs. Defects can be found in time at an early stage and the design quality can be improved significantly. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Moving Object Capture Based on Characteristics of APS-CMOS Image Sensor LI Wei,PAN Zhi-hao,WANG Min Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 47-50.   Abstract （2081）      PDF（pc） （511KB）（765）       Knowledge map    Save With the growing requirement of moving object capture in embedded systems, it is hard to tradeoff the conflict requirements of resolution and capture speed. The proposed method splits motion capture process into motion detection and target capture, which have different emphases on resolution and speed. Using an active-pixel architecture, CMOS image sensor’s hardware characteristics can randomly access the sensor’s image buffer to achieve the switch between working modes of varying trait on the digital signal processing （DSP） platform. Thus, both capture speed and resolution can be guaranteed. With the proposed method, ordinary chips can achieve better performances, which otherwise would require higher performance chips. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Low-Sidelobe Microstrip Array with Circular Polarization for Radio Frequency Identification Applications SUN Zhu,ZHONG Shun-shi,CHEN Kuang-da,TANG Xiao-rong Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 51-53.   Abstract （2361）      PDF（pc） （351KB）（730）       Knowledge map    Save The design of a microstrip antenna array for 2.45 GHz radio frequency identification (RFID) reader applications is introduced with measured results. The array is of simple structure, low sidelobe level and circular polarization characteristics. Its measured sidelobe level is -23.2 dB, and the measured VSWR≤2 impedance bandwidth is 130 MHz (from 2.44 GHz to 2.58 GHz), making it suitable for RFID applications. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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Spectrum Sensing in Cognitive Radio Based on Energy Detection PAN Jian-guo,ZHAI Xu-ping Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 54-59.   Abstract （2208）      PDF（pc） （732KB）（1257）       Knowledge map    Save  Cognitive radio (CR) is viewed as a novel approach for improving utilization of the precious radio spectrum. This paper first reviews the background and concepts of CR, and then investigates energydetection based spectrum sensing by focusing on the spectrum sensing function. To deal with the problem of local sensing characteristic in wireless signal detections in the energy detection process, a distributed M-cooperative detection scheme is presented. Analytical detection probability based on the “OR” rule is presented. Both simulation and the analytical results indicate that, with a small tradeoff between detection probability and false alarm probability, the scheme significantly improves the spectrum sensing ability under low SNR. Related Articles | Metrics | Comments（0）

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n Approach to Generating Integration Test Case Based on Object-Z Specification ZHU Yi-yi1,MIAO Huai-kou1,2,TANG Xin-xiang1 Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 60-65.   Abstract （2122）      PDF（pc） （721KB）（951）       Knowledge map    Save Formal methods have precise description and high-level abstraction capability. Written specification in a formal method avoids consideration of data structures and algorithms in detail at the demand analysis stage. Meanwhile, it can reduce uncertainty and ambiguity in system modeling. This paper proposes a method for describing component models by using Object-Z schema and criteria to generate test a scenario, generating test cases for integrated testing on component systems. Related Articles | Metrics | Comments（0）

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Computation of Lattice Boltzmann Method Based on Graphics Processing Unit FENG Wei-bing,YANG Xiao-ling Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 66-70.   Abstract （1944）      PDF（pc） （647KB）（897）       Knowledge map    Save Computation based on graphics processing unit (GPU) has attracted increasing attention as a new research direction. As an introduction to the high performance of GPU, this paper first analyzes features of GPU as reported in the literature published in the recent years. Computation model of GPU is introduced, and pipeline structure analyzed. Programming on GPU is then discussed. Computation of lattice Boltzmann method (LBM) on GPU is implemented. Related Articles | Metrics | Comments（0）

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Demand Forecast Using Support Vector Machine for a Product Category GAO Jun-jun1，TAN Chong-li1，LIU Yue2，YIN Ya-feng2 Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 71-76.   Abstract （2101）      PDF（pc） （760KB）（929）       Knowledge map    Save Demand forecast is the basis of business operation for a company. Forecast accuracy has a great effect on safety inventory, profit and competitiveness. In this paper, support vector machine (SVM) is used to forecast the demand of a product category including multiple brands. Various factors that affect the product demand such as seasonal and promotional factors are taken into consideration. Data used in model training and assessment are generated from the demand function of this product. Different forecast models such as regression model, double exponent smooth model, Winter model and radial basis function neural network model are used for comparison and evaluation. The results show that accuracy of SVM is superior to other models, which can significantly reduce the inventory level. Therefore SVM is shown to be an effective model for demand forecast. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Distributed Resource Scheduling System Based on Reliability XU Wei-min,CAI Xin-huan,SHEN Wen-feng,ZHI Feng-lin Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 77-80.   Abstract （2109）      PDF（pc） （514KB）（945）       Knowledge map    Save The management of resources and task scheduling in a distributed computing is complex and challenging due to various factors such as the resource’s geographic distribution, heterogeneity, dynamic, distributed ownership with different policies and priorities, varying loads, reliability, and availability conditions. Performance measurement, analysis and prediction of distributed systems have become increasingly important. In particular, accurate load prediction of each computer is crucial in achieving required performance for practical applications. This paper presents a resource schedule algorithm based on its reliability, which is the centre of any scheduling and resource allocation algorithm. The algorithm can effectively resolve the problem of load balancing in a distributed system. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Interruptible Load Management Considering Reliability of Consumers LIU Guo-chun,ZHANG Shao-hua,WANG Xian Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 81-86.   Abstract （2098）      PDF（pc） （722KB）（997）       Knowledge map    Save One way of operating a power network economically and safely is to implement interruptible load (IL) management. IL is an important measure which can ascertain the power outage cost. By considering the reliability indexes such as interruption duration, a new power outage cost function is constructed. A model of interruptible load management based on the function which takes into account consumer reliability is studied. Several case studies are carried out to show that using the model can improve benefit per unit of energy. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Preparation and Characterization of Graphite/nano-ZrO2 Composite Powders LIU Jian-fei1,2 ,HANG Jian-zhong3,SHI Li-yi1,ZHU Wei-de2 Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 87-92.   Abstract （2434）      PDF（pc） （766KB）（1050）       Knowledge map    Save  Graphite/nanosized ZrO2 (GN ZrO2) composite powder was successfully prepared, with ZrOCl2·8H2O being predecessor, by surface modification on the natural flaky graphite particles using a heterogeneous nucleation technique. The effect of the amount of ZrO2 on hydrophilicity of the composite powders was investigated. Hydrophilicity of GN ZrO2 composite powders being modified was greatly improved. Composite powders were characterized by Zeta potential testing instrument and TGA-DSC analytical apparatus respectively. Isoelectric points of composite powder varied from pH=2.5 to pH=5.3 and the antioxidation property improved to some degree because the oxidation gravimetric ratio decreased from 98.9% to 93.1%. In addition, SEM photographs and the EDS analysis indicated that the graphite surface was coated with a layer of dense nano-sized ZrO2 particles, whose size was dozens of nanometers. XPS results showed that the surface of graphite powders exhibited Zr characteristic peak and the electron binding energy of C1s shifted by 0.4 eV toward the higher side. Related Articles | Metrics | Comments（0）

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Experimental Study on Freezing Expansion and Water Transference of Shanghai’s Artificially Frozen Soil QIN Ai-fang1,2,LIN Jin-qian1,2,PU Yi-bin2,GU Tong-xin2,XING Li-li2 Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 93-98.   Abstract （2184）      PDF（pc） （796KB）（1044）       Knowledge map    Save Freezing expansion is the most prominent character of frozen soil, which can bring displacement of ground and therefore is harmful to the surrounding areas. By testing Shanghai’s frozen clay with different frozen quantities and frozen stresses, the relations of consolidated stress are obtained with frozen quantity and frozen stress, and instance of water transference in the frozen process is the results of this study is useful in the design and construction of artificially frozen soil project of Shanghai. Related Articles | Metrics | Comments（0）

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Experiments on Compression Characteristics of Remoulded Soft Clay in Shanghai ZHOU Ke,SUN De-an Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 99-104.   Abstract （2119）      PDF（pc） （661KB）（867）       Knowledge map    Save Differences in compression index (Cc) and swelling index (Cs) of remoulded soft clay in Shanghai measured by different test methods are studied. The tests include isotropic compression test, K0 test and one-dimensional compression test. Differences in compression index are compared based on the results of three isotropic compression tests, two K0 tests, and three one-dimensional compression tests. And differences in swelling index are also compared based on the results of one-dimensional compression tests and isotropic compression-unloading-and-reloading tests. Variation in K0 due to the change of σv is identified from K0 tests, and the relationship between K0 and over consolidation ratio (OCR) is also given. The relationship between Cs and OCR is studied using the results of the three different kinds of tests. Results of these tests are a basis of construction of constitutive models of remoulded soft clay in Shanghai. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Test of Strengthening Negative Moment Area of Reinforced Concrete Continuous Beams with Carbon Fiber Reinforced Polymer YE Hong-yi1,CHEN Yong-xiu2 Journal of Shanghai University（Natural Science Edition）    2009, 15 (1): 105-110.   Abstract （2766）      PDF（pc） （777KB）（1284）       Knowledge map    Save When strengthening the negative moment area of a reinforced concrete (RC) beam, the presented anchorage would be insufficient because the carbon fiber reinforced polymer (CFRP) strips will be cut-off at the place of column. For this reason, strengthening effectiveness of several bonding methods is discussed in this paper based on tests. The supports of continuous beam of the vertical axis from different parts of the carbon fiber strain changes has been studied. By inspection of wing plates in different parts of the CFRP structural capacity increase of the contribution of difference, useful conclusions are obtained. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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Second Order Statistics of an Extended SUZUKI Mobile Fading Channel Model LI Ying-Chun, CHEN Jian, SONG Yang-Xiong, LIN Ru-Jian Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 111-115.   Abstract （2430）      PDF（pc） （540KB）（1227）       Knowledge map    Save The statistics of an extended SUZUKI mobile fading channel model are studied. Closed-form expressions for the secondorder statistics of the envelope process for the analytical model, i.e., the level-crossing rate (LCR) and average duration of fades (ADF) are given. Since the Rayleigh fading channel is a special case of the proposed model, the derived expression can be verified by comparison with results for the Rayleigh fading channel. A numerical optimization procedure has been used to fit the statistics of the proposed analytical model to an equivalent mobile channel for light and heavy shadowing environments. Theoretical and simulation results show that the extended SUZUKI mobile fading channel has excellent performance. Related Articles | Metrics | Comments（0）

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Dynamic Collaborative Merging Scheme for VOD Service over 3Tnet SHI Hai, TIAN Li Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 116-120.   DOI: TN925.5 Abstract （2190）      PDF（pc） （652KB）（1041）       Knowledge map    Save China’s high performance broadband information network, named 3Tnet, is a new network with large-scale video services. Based on the architecture of VOD service over 3Tnet, a new dynamic collaborative merging scheme is proposed. This scheme employs a dynamic collaborative merging scheduling algorithm based on a patching multicast policy to further reduce bandwidth requirement of the edge network for VOD service over 3Tnet. Simulation results show that, with 3 000 movies, the proposed scheme can save about 28.2% bandwidth of the edge network and 47.2% bandwidth of the residential network, respectively, compared with a peer-to-peer chaining policy. Moreover, compared with the patching multicast policy, this scheme can save about 17.6% bandwidth of the edge network by slightly increasing bandwidth (about 3.8%) of the residential network. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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Dual-Band Radio Frequency Identification Printed Antenna GU Jian-Hui, ZHONG Shun-Shi, CHEN Kuang-Da Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 121-124.   DOI: TN82 Abstract （2316）      PDF（pc） （407KB）（1113）       Knowledge map    Save A new design of dual-band radio frequency identification (RFID) printed antenna fed by a coplanar waveguide (CPW) is proposed, which operates in both 2.45 GHz and 5.80 GHz RFID bands. Its two measured impedance bandwidths are 32.0% at 2.45 GHz and 9.8% at 5.80 GHz respectively. The antenna has a simple structure sized 40 mm×40 mm, which is easy to be integrated with active devices and monolithic microwave integrated circuits. Details of the proposed antenna design and the measured results are presented and discussed. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Channel Mismatch Effects in Time-Interleaved A/D Converters HONG Liang, ZHANG Jun-Jie Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 125-129.   Abstract （2136）      PDF（pc） （499KB）（1032）       Knowledge map    Save Bandwidth mismatch effect in time-interleaved A/D converter (TIADC) is studied. Formulas of the signal-to-noise-and-distortion ratio (SINAD) for combination of four different channel mismatches and quantization errors are proposed. The derived formulas can be used for calibration to compensate for the channel mismatch effects. Simulation results are presented to verify the formulas. Related Articles | Metrics | Comments（0）

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Ultra-Wideband Wide-Slot Printed Antenna with Inverted π-Shaped Feed XUE Ling-Long, ZHONG Shun-Shi Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 130-133.   Abstract （2320）      PDF（pc） （391KB）（1143）       Knowledge map    Save A new ultra-wideband wideslot printed antenna with an inverted π-shaped feed is introduced, which is fed by a coplanar waveguide (CPW). The characteristics of the proposed antenna are investigated both numerically and experimentally, then the return loss curve and radiation patterns of the antenna are presented. The experimental results show that the antenna has an impedance bandwidth of approximately 120% (S11≤-10 dB), covering 3.0~12.0 GHz frequency range. Compared with some reported antennas of the same-type, it is noted that the size of the proposed antenna is the smallest among them. Related Articles | Metrics | Comments（0）

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High Order Compact Finite Difference Schemes for Linear Wave Equations LUO Bai-Hua Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 134-141.   Abstract （2272）      PDF（pc） （875KB）（1230）       Knowledge map    Save Low-dissipation and low-dispersion high-order compact finite difference schemes are studied for computation of wave motion. An optimized seven-point sixth order accurate compact finite difference scheme (CO6) is obtained to approximate spatial derivatives, and is compared with the C6 (sixthorder compact) and C8 (eighth-order compact) schemes. For time marching scheme, the fourth order explicit Runge-Kutta methods (RK4 and LDDRK or RK46) are used. The effective wave-number ranges of the spatial schemes, the numerical errors of the various schemes, and the minimum point numbers per wavelength (ppw) for long distance propagation calculation of waves are studied. Based on the comparison, suggestions are given in using these schemes. Finally, a few numerical tests are presented to show accuracy of the schemes in simulation of wave motion. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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CdTe Quantum Dots Fluorescence-Quantum Yield and Biological Labeling CHEN Li-Xia, ZHANG Jian-Cheng, SONG Zhen-Wei, YOU Chen-Xia, DING Yi-Min, SHEN Yue, GUO Jing-Kang Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 142-146.   Abstract （2674）      PDF（pc） （642KB）（1305）       Knowledge map    Save CdTe quantum dots (QDs) were synthesized in an aqueous solution with thioglycolic acid (TGA) as a stabilizing agent to actualize water solubility of semiconductor nanocrystals. The carboxylic acid groups of thioglycolic acid (TGA) stabilizing CdTe quantum dots can form amido bonds with the amine groups of bovine serum albumin by the coupling action to label the protein.Before and after labeling bovine serum albumin (BSA), the change of emission and absorption spectra of CdTe quantum dots as well as their fluorescence-quantum yield were studied by fluorescence and UV-vis spectrophotometer. CdTe-BSA was confirmed by gel electrophoresis after being purified by dialysis. Related Articles | Metrics | Comments（0） Cited: Baidu(13)

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Automated Photoelasticity Stress Analysis HAN Yong-Sheng, ZHANG Dong-Sheng, CUI Yang, LIANG Qiu-Sheng Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 147-152.   Abstract （2717）      PDF（pc） （679KB）（1233）       Knowledge map    Save Phase shift is applied to calculate parameters from photoelastic fringe patterns. Stress components are determined with shear stress differential methods. In planar polariscope, four fringe patterns with specific angles are acquired and the phase map of the orientation of principal stresses derived from isoclinics according to four-step phase stepping. A method is proposed to determine orientation of the first principal stress in the entire field. Similar to Tardy compensation, isochromatic fringe patterns are analyzed in 8 discrete directions. In each direction, phase shift is achieved by rotating the analyzer in the circularly polarized field. With information of the orientation of the first principal stress, the phase map of isochromatics for the entire field is constructed from the 8 phase maps. Thus, stress components within the photoelastic model can be determined. An example is given to illustrate the merits of the proposed methods. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Bayesian Estimate of Stochastic Intensity of Mixed -Poisson Random Varia YU Mei-Ling, ZHAO Fei Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 153-155.   Abstract （2156）      PDF（pc） （250KB）（1112）       Knowledge map    Save This paper studies estimation of stochastic intensity from observed values of mixed Poisson random variables. Characteristics of the Bayesian estimate of the stochastic intensity of a class of mixed Poisson distributions are given, which are then extended to a more general case. This result is an extension of Johnson’s results. Related Articles | Metrics | Comments（0）

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Analysis of Two-Photon Ionization and Photoelectron Imaging -Spectrometry for Potassium Atoms CHEN Fa-Tang, LIU Juan, FAN Rong, LI Yong-Fang Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 156-159.   Abstract （2360）      PDF（pc） （423KB）（1109）       Knowledge map    Save Based on principle of photoelectron angular distribution imaging spectrometry, with potassium atoms as an example, the interference pattern of angular distributions of photoelectrons are obtained using a single photon resonant excitation and two-photon ionization. The angular distribution of photoelectrons is closely related to interference. The interference pattern and information of the atomic energy states are discussed in detail. Related Articles | Metrics | Comments（0）

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Numerical Analysis of Axial Flow Pump Arrangement LIANG Xue-Jie, CHEN Hong-Xun, WEI Pei-Ru Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 160-163.   Abstract （2185）      PDF（pc） （497KB）（1058）       Knowledge map    Save Based on ANSYS CFX 10.0, full 3D numerical simulations of axial-flow pump arrangement are carried out under different operating conditions using two different turbulent models to solve the Reynolds-averaged NavierStokes equations. The head and hydraulic efficiency of pump arrangement are computed, and comparisons made between the calculated and measured results. The trend of calculated results agrees with the experimental results. In the vicinity of the highest efficiency point, the head relative error computed using the standard  k-ε  is the smallest. The computed head is higher than the experimented head with increasing discharge. It is lower than the experimented head with decreasing discharge.  Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Parallel Molecular Dynamics Simulation of Crack on Parallel Clusters LU Hong-Quan, ZHANG Jun-Qian Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 164-168.   Abstract （2449）      PDF（pc） （755KB）（1263）       Knowledge map    Save By discussing the parallel algorithm of molecular dynamics and describing construction of a parallel simulation cluster, the process of parallel molecular dynamics (PMD) programming and its implementation are studied. Installation and application of Lammps, a code of PMD, on the parallel cluster Ziqiang 3000 are introduced. The crack PMD simulation is checked. Related Articles | Metrics | Comments（0） Cited: Baidu(11)

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Distance Measurement Using BinocularCamera with Adaptive Focusing XU Jie, CHEN Yi-Min, SHI Zhi-Long Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 169-174.   Abstract （3052）      PDF（pc） （706KB）（1189）       Knowledge map    Save The method of depth measurement by using binocular-camera is based on the principle of parallax, which provides a new solution to distance measurement by seeking the match point in the 2D-image. In this paper, an improved method is presented to extend the length of depth measurement with adaptive focusing. A concept of sensitivity is presented, which is an important factor for efficient and accurate depth measurement. According to the sensitivity function, an improved algorithm is presented, which is well-performed in the measurement test. Related Articles | Metrics | Comments（0）

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Collaborative Manufacturing Oriented Task Planning Configuration -Management and Collaborative Control ZHAO Zheng-De, ZHAOYu-Liang, YANG Li-Chao Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 175-180.   Abstract （2297）      PDF（pc） （728KB）（1232）       Knowledge map    Save By analyzing the principle requirements and implementation of collaborative manufacturing (CM), this paper proposes general system construction, the corresponding function of task planning, configuration management, and collaborative control. A series of tasks can be accomplished including management modeling of collaborative manufacturing in task allocation, collaborative strategy of personnel allocation management, task planning, task implementation, business process, and collaborative control of personnel during the reviewing phase. This enables the leader of alliance (LA) and out-manufacturers (OMs) to work together and complete production process with high efficiency and speed. Related Articles | Metrics | Comments（0）

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Motion Restricted Condition and Singular Configuration for Mecanum -Wheeled Omni-Directional Motion System WANG Yi-Zhi, CHANG De-Gong Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 181-185.   Abstract （2508）      PDF（pc） （578KB）（1121）       Knowledge map    Save Though kinematics analyzing for Mecanum wheeled omni-directional motion system, the restricted conditions of the system to move in omnidirections are presented. These conditions include relationships of the wheel structure, wheels number and the system lay-out to system to move in omni-direction. The singular configuration of the system is showed out from two class system layouts, it is presented that how to decrease or avoid the singular configuration of the system to move in omnidirections. Related Articles | Metrics | Comments（0）

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Error Analysis and Compensation of Plane Electronic Compass MA Cheng-Yao, QIAN Jin-Wu, SHEN Lin-Yong, ZHANG Ya-Nan Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 186-190.   Abstract （2529）      PDF（pc） （574KB）（1288）       Knowledge map    Save The principle of plane electronic compass is introduced, and the possible error and the error sources are analyzed. The deflection caused by local magnetic influence, for both the source and components, is analyzed. Based on the study, a deflection equation is obtained. The least square method is used for compensation, resulting in a maximum azimuth error of less than 1° so that the accuracy is increased. The results indicate that the methods of compensation can be widely used in similar applications. Related Articles | Metrics | Comments（0） Cited: Baidu(7)

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Simulation of Fluctuating Wind Fields around Two Kinds of Civil-Engineering Structures XU Xu, QU Ying-Hui, LIU Yu Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 191-198.   Abstract （2531）      PDF（pc） （783KB）（1277）       Knowledge map    Save Using a spectral representation method in the theory of stochastic simulation, and the fast Fourier transform (FFT) technology, fluctuating wind fields around two typical structures are simulated with MATLAB. Time-history curves of fluctuating wind at some nodes are presented. Correlation of different points on the structure is considered. Various methods have been used to verify correctness of the numerical results. The program is showed to be very efficient with the FFT. Meanwhile, precision of the traditional spectral representation is preserved. It is found that the simulation results of fluctuating wind well meet the requirement of engineering analysis. Related Articles | Metrics | Comments（0） Cited: Baidu(15)

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Interaction between Soil and Inclusions in Retaining Wall Reinforced -with Horizontal and Vertical Inclusions PENG Meng-Yuan, HUANG Chao, PENG Ji-Min, ZHANG Meng-Xi Journal of Shanghai University（Natural Science Edition）    2009, 15 (2): 199-204.   Abstract （2217）      PDF（pc） （750KB）（1333）       Knowledge map    Save In conventional reinforced soils, the reinforcements are often laid horizontally in the soil. A novel concept of soil reinforced with horizontal and vertical (H-V) reinforcements is proposed in this paper. In the proposed H-V reinforced soil, besides conventional horizontal reinforcements, some vertical reinforcing elements are also placed in the soil. The finite element method is used to analyze the interaction between soil and reinforcements. The strength reduction method is used to study instability of the retaining wall. With the method of c-tanφreduction, comparisons between H-V reinforced soil and traditional reinforced soil in the safety factor and plastic strain distribution are made when the finite element method (FEM) models reach instability. Related Articles | Metrics | Comments（0）

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