Journal of Shanghai University（Natural Science Edition）

Ant Colony Optimization Routing Based on Congestion Control in WSNs

2012, 18(6): 551-554. doi:10.3969/j.issn.1007-2861.2012.06.001

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Wireless sensor network (WSN) suffer from the problems of congestion, leading to packet loss and excessive energy consumption. This paper propose an improved energy-efficient ant-based routing (IEEABR) algorithm to find optimization path by taking into account the packet queue length of media access control (MAC) layer, which is the degree of congestion information. Simulation results show that IEEABR has several features such as high packet delivery ratio, low overall latency and high throughput, therefore is suitable for WSN routing protocol.

A New Method of Adaptive Wiener Filtering

LI Dong-bing,LI Guo-ping,TENG Guo-wei,ZHAO Hai-wu,WANG Guo-zhong,LI Ping

2012, 18(6): 555-560.

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Aimed at improving the insufficient result of classic Wiener filtering, a new adaptive Wiener filter is proposed. The new filter can adaptively select the filter template from different given templates, giving a better filtering result. The traditional Wiener filter seeks to suppress noise in images at the cost of losing some edge information, while the proposed method can overcome the problems. Experimental results show that the proposed filter gives improved performance both in subjective and objective evaluations as compared to the classic Wiener filtering.

Improvement of Solder Joint Reliability for Thin Small Outline Package

QIAN Jia-min,XU Run,TANG Min-yan

2012, 18(6): 561-566. doi:10.3969/j.issn.1007-861.2012.06.003

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The influence of print circuit board design on solder joint reliability (SJR) of thin small outline package (TSOP) has been investigated in a specifically designed experiment. The SJR test board includes three layout parameters. The TSOP component has been soldered to the test board under surface mount process. Solder joints’ crack length subject to each design parameter has been measured after the samples went through thermal cycling from -40 to 85 ℃. The mechanism of solder joint crack has been discussed. In addition, two judgment criteria are chosen according to the crack length. The results show that SJR of TSOP can be improved by long size pad, organic solderability preservatives (OSP) surface finish and offset double placement.

Effect of Electronic Structure on Adsorption of H and B Atoms on Ordered Ni-3Fe Surface

LIU Jing-ying, XIE Yao-ping, CHEN Ye-xin, HUANG Xiao-jun, ZHAO Shi-jin

2012, 18(6): 567-571. doi:10.3969/j.issn.1007-2861.2012.06.004

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This paper performs first-principles calculations based on the density functional theory (DFT) to investigate the interaction of H and B atoms with ordered Ni₃Fe (111) surface. The results showed that the B atom can be strongly absorbed onto the surface, and absorption energies of B atoms are much lower than that of H atoms. It indicates that the B atom can be easily bound by the ordered Ni₃Fe surface, which occupies the suitable site and inhibits the access of H into the matrix. Furthermore, electronic structure analysis is presented to understand that the adsorption energy of H atom higher than that of B atom is accrediting to its anti-bonding state being pushed up to the Fermi level when an H atom is absorbed on the (111) surface of the ordered Ni₃Fe

Preparation of Spinel Li₄Ti₅O₁₂ and Electrochemical Performance

CAO Shao-mei, ZHANG Da-wei, FENG Xin, CHI Tao, SHI Li-yi

2012, 18(6): 572-576.

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Nano-sized Li₄Ti₅O₁₂ was prepared at a low temperature with TiO₂ and lithium acetate as starting materials. Atom-sized blending was achieved by the liquid pre-dispersion and melting-soakage with ethyl alcohol as solvent. Calcination was carried out by different steps at relative low temperatures. The X-ray diffraction (XRD), scanning electron microscope (SEM) and size distribution tests showed that the Li₄Ti₅O₁₂ was spinel structure with an average size of about 550 nm. The Li₄Ti₅O₁₂ showed good electrochemical performance with the first charge-discharge capacity achieving 165 mA·h/g at 0.1 C and having a steady voltage and good cyclic performance. 

Synthesis of ZnTe Modified Cu Ion Doped ZnSe Quantum Dots

FU Teng-fei, LI Dong-mei, TANG Zi-long

2012, 18(6): 577-581. doi:10.3969/j.issn.1007-2861.2012.06.006

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This paper studies synthesis of ZnSe quantum dots (QDs) doped with Cu ion in an aqueous solution by using 3-mercaptopropionic acid (MPA) as ligand, and then modified its surface by ZnTe (ZnSe:Cu/ZnTe). The structure, morphology and optical properties of QDs are characterized with X-ray diffraction (XRD), high resolution transmission electronic microscopy (HRTEM), ultraviolent-visible spectroscopy (UV-VIS) and photoluminescence (PL) spectroscopy. The sizes of QDs obtained were 4～6 nm. Under an excitation wavelength of 325 nm, peaks of ZnSe:Cu/ZnTe at 510 nm were observed. Especially, the peaks moved to 540 nm after a heat processing at 160 ℃. The facts indicate that the fluorescence emission peak’s positions of ZnSe:Cu QDs capped by ZnTe surface modification can be changed.

Discretization of Speed Adaptive Full-Order Flux Observer for Induction Motors

SONG Wen-xiang, ZHOU Jie, YIN Yun

2012, 18(6): 582-588. doi:10.3969/j.issn.1007-2861.2012.06.007

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Some important information of the induction motor which cannot be measured directly can be obtained by state reconstruction. However, the mathematical model of a full order observer is a four order differential equation, which is not easy to analysis and digitally implemented. Different discretization methods have different effects on the system performance. Four methods of full order observer digital realization are proposed based on the single footwork principle in numerical integration. These are first-order Euler method, second-order Trapezoidal method, and third-order and fourth-order Runge-Kutta methods. Validity, efficiency and precision of the four methods are shown with results of experiments on a 2.2 kW induction motor platform. 

Inverse Kinematics Algorithm of 7-DOF Manipulator Based on Self-Motion

CUI Ze, HAN Zeng-jun

2012, 18(6): 589-605. doi:10.3969/j.issn.1007-2861.2012.06.008

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Based on the structure of a robot manipulator with seven degrees of freedom (7-DOF) and its self-motion characteristic, a geometric method is proposed to find solution of inverse-kinematics of a robot. The algorithm is at the level of position for inverse kinematics. Self-motion of the redundant manipulator is described and used to solve inverse kinematics of the redundant manipulator. The inverse-kinematics is solved using its self-motion. Computation involved in the method is easy. It is efficient in solving the inverse kinematics.

Extremal Ranks of Centrosymmetric Solution to System of Matrix Equations

ZHANG Xiang, HAO Lei, WANG Qing-wen

2012, 18(6): 596-600. doi:10.3969/j.issn.1007-2861.2012.06.009

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A new general form and the extremal rank of the centrosymmetric solutions to A₁X=C₁and A₃XB₃=C₃ are derived.

p-Cosine Transform and Its Application in Convex Geometry

GUO Lu-jun

2012, 18(6): 601-605. doi:10.3969/j.issn.1007-2861.2012.06.010

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Spherical integral transformations are indispensable tools in integral geometry and convex geometry. This paper gives a direct proof to the injectivity of p-cosine transformation forp=2k+1, k∈N. Using the injectivity properties of p-cosine transformation, an important result of uniqueness of star body is obtainted, i.e., a star body is uniquely determined by its p-centroid body forp=2k+1, k∈N

Modeling and Simulation of Versatile Waiting-Area at Isolated Signalized Intersection

JIANG Jin-sheng, DONG Li-yun

2012, 18(6): 606-611.

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A multilane cellular automaton model is proposed in investigating an isolated signalized intersection system with a versatile waiting-area. The effects of the length of waiting-area and the cycle time on the traffic capacity are analyzed. Numerical results show that proper setting of the versatile waiting-area can improve the traffic capacity significantly in the case of large inflow of vehicles. Both stop time and travel time at the intersection are reduced while the stop frequency is increased accordingly. For a given cycle time, a critical length of waiting-area exists. Below the critical value, the capacity increases with the length of waiting-area. When the length of waiting-area is larger than the critical value, the capacity decreases.

Buckling Simulation of Multi-walled Carbon Nanotube in Compression and Bending with ANSYS

CAI Mao-yuan, CHANG Tien-chong

2012, 18(6): 612-616. doi:10.3969/j.issn.1007-2861.2012.06.012

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Shell model is widely used in studying the mechanical behavior of carbon nanotube, but the effective thickness and the physical thickness are greatly different. Especially the effects between two layers have to be considered in the study of multi-wall carbon nanotube. This paper proposed a carbon nanotube sandwich continuum model with three layers continuum to simulate one individual nanotube, the inner layer continuum simulate σ-bond, the two outer layers simulate π-bond and Van der waals force between two individual nanotubes. In this way finite element analysis could directly study mechanical behavior of multi-walled carbon nanotube. The model is proved valid by comparing the result with molecular dynamical (MD).

Dynamic Response of Pasternak Beams on Viscoelastic Foundations to Moving Load

SHI Kang-li, DING Hu, CHEN Li-qun, CHU De-lin

2012, 18(6): 617-621.

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Dynamic response of Pasternak beams on viscoelastic foundations to a moving load is proposed by integral transformation in this paper. The Green’s function of the beam is obtained by means of two-dimensional Fourier transform. Deflection of the beam is represented using inverse Fourier transform. The theorem of residue is then applied to represent the generalized integral in the form of contour integral in the complex plane. Studies on the influence of parameters of beam and subgrade are provided with illustrations. It is clear that viscosity and shear modulus of subgrade have significant effect on the deflection of the beam. Numerical solution to the integral expression is studied with spline interpolation, showing that the obtained closed-form solution is correct.

Dynamical Analysis of Arterial Wall

SHEN Jia-cheng, REN Jiu-sheng

2012, 18(6): 622-626. doi:10.3969/j.issn.1007-2861.2012.06.014

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A dynamical differential model for the arterial wall under pulse pressure is established based on a fiber-reinforced two-layer composite heterogeneous hyper-elastic tube within the finite deformation theories of continuum mechanics. Effects of the residual stress, smooth muscle activity and fiber dispersion are discussed. Time-history curves, frequency spectra, phase diagrams, Poincare maps and stress distribution curves are obtained through numerical computation. Dynamical response of the arterial wall taking into account the effects of the value and frequency of the pressure are discussed based on the nonlinear dynamical theory.

Experimental Study on Hydro-Mechanical Behavior of Unsaturated Silt

SUN De-an, YANG Xian-cai

2012, 18(6): 627-633. doi:10.3969/j.issn.1007-2861.2012.06.015

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使用非饱和土三轴试验仪，对击实非饱和粉土进行吸力控制的三轴排气排水剪切试验，得到不同试验条件下剪切时的应力应变关系和吸排水情况.首先，通过改变试样的初始密度，得到不同孔隙比条件下的三轴剪切试验结果，确定非饱和试样发生剪切膨胀和剪切体缩的临界孔隙比约为1.0；其次，通过改变施加吸力的大小，获得不同吸力条件下剪切时的应力应变关系和吸排水情况，并确定试样的临界吸排水吸力值为25～35 kPa；最后，通过改变净围压大小，得到不同净围压情况下的应力应变关系和吸排水情况，其中在剪切过程中不同净围压下的含水量变化大致相同.

Nonlinear Bending Analysis of Timber Beam Strengthened with Fiber Reinforced Polymer

LU Xin, YANG Xiao, SONG Shao-hu

2012, 18(6): 634-639. doi:10.3969/j.issn.1007-2861.2012.06.016

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Taking into account the effects of bi-modulus for tension and compression of fiber reinforced polymer (FRP) layers and second order deformation and axial tension of the nonlinear bending of a timber beam, nonlinear bending of simply-supported FRP-strengthened timber beams under a uniform transversal load is investigated with the perturbation method. Asymptotic expressions of deflection and bending moments of the FRP-strengthened timber beam are obtained, and numerical results are presented. It is revealed that deflections and bending moments of nonlinear bending of the FRP-strengthened timber beam are smaller than those of linear bending. When the dimensionless load is less than 5, deflections and bending moments of nonlinear and linear bending are almost equal to each others, and there are no distinct differences. The difference between them increases when the load is increased. When the dimensionless load is greater than 20, the effect of nonlinear bending is remarkable, and a model of nonlinear bending of the FRP-strengthened timber beam should be used.

Comparative Experiments on Reinforcement Effects of Denti-Inclusion Forms

SUN Liang-fu, ZHANG Meng-xi

2012, 18(6): 640-644. doi:10.3969/j.issn.1007-2861.2012.06.017

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Three model tests of reinforced sand cushion with denti-inclusions on soft ground under embankment were conducted, and the reinforcement effects of denti-inclusion forms compared. The results show that the biaxial grid reinforcement of denti-inclusions can better utilizing tensile strength. Reinforcement can be enhanced with improved integrity of denti-inclusions. The bearing capacity of soft ground is significantly increased, the settlement, differential settlement and the lateral displacement of embankment slope reduced.

Test of Shear Capacity of Pre-stressed High-Strength Concrete Pipe Piles

LOU Zhi-jun, WU Jiang-bin, SONG Qing-jun, SUN De-an

2012, 18(6): 645-650. doi:10.3969/j.issn.1007-2861.2012.06.018

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Tests on shear capacity of the pre-stress high-strength concrete (PHC) AB400(80) pipe piles were carried out, without axial force and under an axial forces of 1 300 kN, respectively. The loading devices and testing method were introduced first in this paper. The cracking and ultimate shear capacities of PHC-AB 400(80) were obtained with and without the axial forces. The failure process during shearing was studied based on the observation of crack development and an analysis of the maximum principal stress and its angle of concrete in the shear span section. Comparison between the values of shear capacity calculated according to the Standard of Pre-stressed Concrete Pipe Pile and from the test results shows that the former is about 58% of the later. The role of stirrup should be taken into account in the formula for calculating the shear capacity of PHC pipe piles.

Effects of Exposure to Ultra High Static Magnetic Fields on Antioxidation and Immune Functions of Mice

HONG Xiao-tong, LIAO Xian-yan, WENG Xin-chu

2012, 18(6): 651-655. doi:10.3969/j.issn.1007-2861.2012.06.019

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Study the effects of exposure to ultra high static magnetic fields on antioxidation and immune functions of mice. Four-week old mice were exposed to the static magnetic fields with magnetic intensity of 12 Tesla (T) for 2 hours every day, and continued for 7 days. On the ninth day, the mice were sacrificed. Livers and kidneys were taken to measure the activity of Catalase (CAT), Superoxide Dismutase (SOD), Total antioxidant capacity (T-AOC), Glutathione peroxidase (GSH-Px) and the content of Maleic Dialdehyde (MDA). Also, thymus and spleen were obtained to measure their index and the splenic lymphocyte proliferation. Besides, blood of mice was collected by taking the eyeball and the content of white cells in the peripheral blood of mice was detected. Compared to control group, activity of CAT, SOD, T-AOC and GSH-Px in kidney in the experiment group were increased significantly. The content of MDA was decreased significantly. Activity of SOD and GSH-Px in liver was enhanced, and the content of MDA decreased significantly. Furthermore, splenic lymphocyte proliferation was increased, and the index of thymus and the content of white cells in peripheral blood were increased remarkably. Exposure to ultra high static magnetic fields can improve antioxidation and immune functions of mice.

Order Models for Call Option of Retailers Based on Risk Appetite

YE Liang, SONG Guo-fang, WANG Jian

2012, 18(6): 656-660. doi:10.3969/j.issn.1007-2861.2012.06.020

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Option tools create a new model of supply chain collaboration which enables suppliers and retailers jointly to be liable for the risks of market uncertainty. Traditional supply chain researches assume that both parties are mainly risk neutral. However, different managers have different needs for risk in practice. Application of Conditional Value at Risk (CVaR) can weigh the scale of risk and reflect the risk appetite. The decision-making objective function is modified on the basis of the approach and a model of option contract in a two-level supply chain. The chain consisting of a single retailer and a single supplier is build under stochastic demands. Obtaining the optimal amount of the retailer's option by analyzing the models, the paper reveals that the risk attitude has a significant impact on the optimal amount of call options and revenue, that is, the higher degree of risk aversion, the smaller order volume and revenue. A numerical example is provided to verify the conclusions drawn in this paper.

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