Table of Content

20 June 2012 Volume 25 Issue 3

  

Content

A brightness classification and improved dichotomy based license

XU Lei, ZHANG Xiao-Ning

J4. 2012, 25(3):  1-6.  doi:10.3976/j.issn.1002-4026.2012.03.001

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      License plate (LP) segmentation can easily be affected by rim, noise and LP rotation, which causes low segmentation accuracy. We presented a goodrobustness segmentation algorithm for the issue. The algorithm performed brightness classification and grayscale enhancement in the preprocessing stage before tilt correction and localization of the upper and lower boundaries. An improved dichotomy algorithm was then applied to segment LP characters. We implemented precise border localization for characters 1, 2, 6 and 7. Experiment shows that the algorithm has low computational burden and can effectively overcome such negative influences as low contrast, blurness, character adhesion and LP tilt.

Analysis of traction energy consumption of urban rail transit

LIU Peng, TIAN Qiong

J4. 2012, 25(3):  7-11.  doi:10.3976/j.issn.1002-4026.2012.03.002

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      We collect and generalize the factors impacting urban rail transit traction energy consumption. We further get a more comprehensive factor system. We also establish a physical model of traction energy consumption with daily variable factors as varibles. We further establish a multiple linear regression statistical model. The model is applied to the prediction of traction energy consumption of Beijing Metro Line 2. Results indicate that the model can predict traction energy consumption with higher accuracy. The model also has good explanation and prediction capability.

Modeling and solving of balance-based single track railway  mixed passenger and freight trains rescheduling

HUO Jian-Wei, WU Jian-Jun

J4. 2012, 25(3):  12-17.  doi:10.3976/j.issn.1002-4026.2012.03.003

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      We established a 0~1 Mixed-Integer Programming (MIP) model of passenger and freight trains with weighted delay time balance as a target parameter for the issue of single track railway rescheduling. We employed layered decomposition technology to build a dynamic regional local optimization algorithm to solve the issue. We also analyzed its example and verified its effectiveness.

Route decision of hazmat shipments with maximum risk constraint

PENG Shan-Shan, SUN Hui-Jun

J4. 2012, 25(3):  18-22.  doi:10.3976/j.issn.1002-4026.2012.03.004

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      This paper establishes a route choice model with the maximum risk constraint based on the definition of hazmat material transportation risk. The model takes into account the effect of the social vehicles on the travel time of hazmat shipments and the total risks of transportation network. We design a corresponding particle swarm optimization algorithm to solve the model. We eventually use numerical examples to analyze the effectiveness of the model and the algorithm. Computation results show that the consideration of the maximum risk constraint can significantly decrease the total transportation network risks of the hazmat shipments.

RBF neural network based urban expressway short-term traffic flow prediction

ZHENG Xuan-Chuan, HAN Bao-Ming, LI De-Wei

J4. 2012, 25(3):  23-28.  doi:10.3976/j.issn.1002-4026.2012.03.005

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       We analyzed and compared the effects of gray model GM (1,1) and RBF neural network model on short-term traffic flow prediction to test their feasibility and applicability. Practical instances show that gray model is inapplicable to the short-term prediction of traffic flow, but RBF neural network model is applicable. Moreover, we can acquire higher prediction accuracy when the distribution density of the radial basis function is from 0.8 to 1.0.

An intersection motor vehicle traffic behavior probability based delay model

ZHANG Hui, ZHANG Xiu-Yuan

J4. 2012, 25(3):  29-33.  doi:10.3976/j.issn.1002-4026.2012.03.006

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      We derive the probability and average delay time of each traffic behavior with the analysis of traffic behavior at single-controlled intersection, signal cycle and effective green light time. We also present a traffic delay model analyzing the probability of all traffic behavior. We employ Beckham Model to calculate traffic flow delay, taking the intersection at East Zhongshan Road and South Jianshe Street as an example. The error is two percent, less than the error range, by the comparisons of results. It demonstrates that traffic behavior probability based delay model can provide an estimation approach for the calculation of intersection average vehicle delay. The acquired average traffic delay can also be served as an index to assess the intersection service level.

Existence and uniqueness of the positive solutions of boundary value of a class of singular fractional-order differential equations

YUAN Shao-Yan, LIU Yan-Sheng

J4. 2012, 25(3):  34-38.  doi:10.3976/j.issn.1002-4026.2012.03.007

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      This paper employs the theory of mixed monotone operator to address the existence and uniqueness of the positive solutions of boundary value of a class of singular fractionalorder differential equations.

H_∞ fault detection of a distributed singular timedelay system

LIU Gao-Wei, HAO Chun-Mei, CHEN Li

J4. 2012, 25(3):  39-44.  doi:10.3976/j.issn.1002-4026.2012.03.008

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      We design an observer-based fault detection filter that serves as a residual generator. We regard the design of fault detection filter as H_∞ filtering. We further present the sufficient condition that guarantees the existence of the H_∞ fault detection filter of a singular time-delay system with Lyapunov-Krasovskii. A linear matrix inequality is applied to the solution of the problem.

Evolution and retrival of the Rydberg wave packet of a quantum bouncing ball in a gravitational field

GAO Feng, CAO Xue-Cheng, LI Ai-Feng, CONG Xiao-Yan, ZHAO Wen-Li

J4. 2012, 25(3):  45-49.  doi:10.3976/j.issn.1002-4026.2012.03.009

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      Rydberg wave packet that is employed to analyze the dynamics of quantum mechanical systems is a very important method for studying the relation between classical and quantum mechanics. We investigate the evolution and retrival of the Rydberg wave packet of a quantum bouncing ball in the gravitational field from autocorrelation function and probability density. Results show that the quantum system is not completely retrievable.

The features of partially coherent ring vortex

LI Yu-Duo, LI Xiang-Ying, ZHOU Li-Feng, WANG Wen-Lei

J4. 2012, 25(3):  50-53.  doi:10.3976/j.issn.1002-4026.2012.03.010

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       We present the partially coherent nature of the annulus vortex beams based on the transmission theory of partially coherent light. We also make a detailed analysis for the annulus vortex beam. We further discover the impact of the change of the relative width s/w0 and the topological charge intensity distribution number m on light intensity distribution in z=0 section. We give the overlapped coherent vortex of two parallel and off-axis partially coherent beams. We eventually analyze the change of light intensity in a overlapped field with the relative distance from axis d/w0 and the coherent parameter α. Moreover, composite coherent light vortex will change into composite light vortex when the paremeter α approaches infinity.

he impact of indium clusters on the photoluminescence of InN

YANG Yuan-Ling, ZHU Xue-Liang

J4. 2012, 25(3):  54-57.  doi:10.3976/j.issn.1002-4026.2012.03.011

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       We investigated the optical properties of InN films by photoluminescence. Experiments show that InN with different crystal structure exhibits different photoluminescence peaks at different temperature. The photoluminescence peaks show abnormal blue-shift phenomenon for the InN sample with indium clusters. The phenomenon is caused by the interface state between the InN and Indium clusters.

Impact of tube PECVD process on the refracitve index of silicon nitride thin film

REN Xian-Kun, MA Yu-Ying, ZHANG Li-Ming, LIU Peng, JIANG Yan-Sen, XU Zhen-Hua, JIA He-Shun, CHENG Liang, ZHANG Chun-Yan

J4. 2012, 25(3):  58-61.  doi:10.3976/j.issn.1002-4026.2012.03.012

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      Refraction index is an important parameter reflecting film composition and density. It also reflects preparation quality of thin film, which directly affects the transformation efficiency of a solar cell. This paper investigated the impact of radio frequency power, chamber pressure, substrate temperature and the ratio of saline and ammonia on the refraction index of silicon nitride thin film deposited on a c-Si solar cell. We analyze the reason that refractive index of azotized silicon thin film changes with different deposition conditions.

Preparation and antibacterial activity of Fe₃O₄/Ag nanocomposites

WU Jia-Pei, BAI Jun-Jie, LI Zhi-Peng, ZHANG Dong-Shun, FAN Xu-Ri

J4. 2012, 25(3):  62-65.  doi:10.3976/j.issn.1002-4026.2012.03.013

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We prepare Fe₃O₄ nanoparticles by solvothermal routes. We obtain Fe₃O₄/Ag nanocomposite with Fe₃O₄ nanoparticales as magnetic core, reaction with glucose in a hightemperture and high-pressure reactor and the coated nanoparticles reaction with AgNO₃ by the reduction of chitosan. Their morphology and structure are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Determination of antibacterial test of minimal inhibitory concentration and minimum bactericidal concentration shows that composite materials Fe₃O₄/Ag have better antibacterial activity.

Analysis of anthocyanins in three species Nelumbinis flos. by HPLC-Electrospray Ionization/Quadrupole-Time of Flight-Mass/ Mass Spectrometry

XU Shuang-Shuang, LIU Wei, GUO Ying-Hui, WANG Ping, SUN Yu, LIU Jian-Hua, WANG Xiao

J4. 2012, 25(3):  66-70.  doi:10.3976/j.issn.1002-4026.2012.03.014

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We employed HPLC-Electrospray Ionization/Quadrupole-Time of Flight-Mass/Mass Spectrometry (HPLC-ESI/Q-TOF-MS/MS) to analyze the anthocyanins in three species Nelumbo nucifera. The anthocyanins were extracted with methanol containing HCl (φ_HCl= 0.1%) and then purified on an Amberlite XAD-7 column. We applied an Amethyst C18 column (250 mm×4.6 mm, 5 μm) to HPLC analysis with water methanol-water (containing trifluoroacetic acid(φ_C2HF3O2=0.05%)) in gradient as mobile phase. The eluates were then detected by ESI/Q-TOF-MS/MS. We altogether identified six species anthocyanins from these Nelumbo nucifera. We further determined their contents by pH-differential spectrophotometry. It provides theoretical foundation for further development and utilization of Nelumbo nucifera resources.

Research on cellulase degradation extraction of polysaccharide in rose dregs

ZHANG Yue-Hui, MA Yao-Hong, Shi-Jian-Guo, YANG Dun-Hui

J4. 2012, 25(3):  71-74.  doi:10.3976/j.issn.1002-4026.2012.03.015

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       We employ single factor test and orthogonal test design method L9 (34) to analyze such influence factors as enzymolysis temperature, enzymolysis pH, enzymolysis time and cellulose amount on the yield rate of the polysaccharide. We also use reducing sugar analyzer to determine the amount of polysaccharide. Results show that temperature and pH are two dominant factors. The optimal enzymolysis condition is temperature of 50 ℃, pH of 4.6, 150 min and cellulose amount of 4.5%. The extract ratio of rose dregs polysaccharide is 11.1% and the yield rate of soluble polysaccharide is 4.49% in condition of the ratio of rose dregs and water of 1∶30, temperature of 100 ℃ and extract time of 5 h.

Pretreatment of blood specimens and their enzyme electrode method  analysis

SHI Jian-Guo, LIU Jin-Yu, SUN Shi-Qing, ZHANG Juan

J4. 2012, 25(3):  75-79.  doi:10.3976/j.issn.1002-4026.2012.03.016

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      We employed enzyme electrode to assess the effect of glyceraldehydes and sodium fluoride on the preservation of glucose and lactic acid in blood specimens. Experimental results show that glyceraldehydes is better than sodium fluoride in the preservation of glucose contents. However, it can not serve as the inhibition regent of lactic acid. The lactic acid remains almost constant as treated with sodium fluoride at 4 ℃.

High-precison barycentric rational interpolation collocation method of wave problems

MA Yan, WANG Zhao-Qing, TANG Bing-Chao

J4. 2012, 25(3):  80-87.  doi:10.3976/j.issn.1002-4026.2012.03.017

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       We construct the differentiation matrices of an unknown function regarding temporal and spatial variables for the given computational nodes in temporal and spatial fields with the approaximation of barycentric rational interpolation to the function. We initially acquire discrete algebraic equations of a wave equation and its definite conditions by inserting barycentric rational interpolation of an unknown function into the governing equation of the wave equation. We then denote the discrete algebraic equations as a concise matrix with the notation of differentiation matrices. We eventually obtain the displacements of the wave equation on the nodes by replacement method and applying boundary and initial conditions. Numerical examples demonstrate that the approach has such advantages as simple computation, easy programming and high precision.

An automation control system of an emulsified asphalt production equipment

ZHENG Jiang-Hua, WU Hao, LIU Cheng-Ye, MA Shi-Guo

J4. 2012, 25(3):  88-91.  doi:10.3976/j.issn.1002-4026.2012.03.018

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       We employ a PLC process control system to perform online monitoring of the liquid level, flow, temperature and pressure in the Elestex production process.In order to increas the burdening accuracy of the Elestex and implementing the automation control of Elestex production. The system can control a switch and its opening and perform online monitoring. Experiments show that the system is stable and reliable and can produce the qualified Elestex.

Microstructure and mechanical properties of welded joint of AZ31 magnesium alloy by DC-TIG welding

ZHANG Xin-En, ZHOU Ji-Xue, ZHAN Cheng-Wei, ZHAO Dong-Qing, LI Wei-Hong, TANG Shou-Qiu, YANG Yuan-Sheng

J4. 2012, 25(3):  92-94.  doi:10.3976/j.issn.1002-4026.2012.03.019

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      Argon tungstenarc welding (TIG) is the most popular welding method for magnesium alloys. AZ31 extruded plates with thickness of 6.0 mm were welded by DC-TIG welding. Microstructure and mechanical properties of welded joint of AZ31 magnesium alloy were studied by optical microscopy, scanning electron microscopy and tensile test machine. The microstructure analysis shows that the welded joint is composed of base material, heat affected zone and weld zone. A transition zone appears near the groove between the heat affected zone and the weld zone, which is the mix-fusion zone. The average tensile strength and the elongation of the welding joint is 241.0 MPa and 13.8% respectively, which arrives to 86.0% and 13.8% respectively of the base material. The fracture of welding joints is located in heat affected zone and the fracture surface presents mix fracture characteristics.

A DNS based reducing sugar detector

GAO Gao-Heng, ZHOU Wan-Li, ZHU Si-Rong, BI Chun-Yuan, DIAO Xiao-Hua, SHI Jian-Guo

J4. 2012, 25(3):  95-97.  doi:10.3976/j.issn.1002-4026.2012.03.020

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       We designed a DNS based reducing sugar detector. It has such advantages as low-concentration reducing sugar detection, convenient operation, easy maintenance, high accuracy and good repeatability. It employs colorimetry to detect the differential light absorption value of dye liquor before and after heating and then to calculate the content of reducing sugar in a sample. We discover that the content of reducing sugar is proportional to the light absorption value. Glucose of 0.1% is used to calibrate measurement. The linear rate of more than 0.99 exists when the concentration range is between 0% and 0.1%. The detector can stably detect the content of reducing sugar in beer, sorbitol and ferment.

Design and development of a new rotary mechanical and electrical integrated ocean current meter

LU Cheng-Jie , XU Xiao-Fei , ZHOU Yang., HUI Li

J4. 2012, 25(3):  98-102.  doi:10.3976/j.issn.1002-4026.2012.03.021

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        We design a new intelligent electromechanical rotary ocean current measurement meter in view of high-threshold flow rate, large volume, and poor stability of a traditional rotary paddle ocean current meter. The meter includes an underwater detector and a overwater receiver. It employs ATxmega microcontroller as a core control device so it has dual CPU structure. The underwater detector has such new characteristics as an independent draw bar and a separate tail. Comarative test shows that the meter works stably.

Finite-time collision-free coordination control approach for autonomous underwater vehicles

YUAN Jian, ZHANG Wen-Xia, ZHOU Zhong-Hai

J4. 2012, 25(3):  103-107.  doi:10.3976/j.issn.1002-4026.2012.03.022

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       This paper addresses the finite-time cooperative control for autonomous underwater vehicles (AUVs). We present a multi-agent control based finite-time consensus tracking control law. A virtual force is given to achieve the collision-free coordination control among many AUVs by vector composition with the law. Simulation results demonstrate the effectiveness of the proposed control scheme.

Linux based node control software for sea floor observatory network

LV Bin, DU Li-Bin, HE Hai-Jing, WU Cheng-Xuan, LI Zheng-Bao

J4. 2012, 25(3):  108-112.  doi:10.3976/j.issn.1002-4026.2012.03.023

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      A node system serves as a communication relay or a control terminal to obtain real-time submarine data information. The paper presents a Linux based software design approach for sea floor observatory network node circuit. It highlights hardware components of node circuit, software functionality analysis and program design of a node client. Experiments prove that the node control software is stable and reliable, easy to be monitored and maintained by a shore station.

A survey of human gait recognition

ZHANG Yuan-Yuan, JIANG Shu-Ming, WEI Zhi-Qiang, ZHANG Jian-Feng, XU Shi-Jie

J4. 2012, 25(3):  113-118.  doi:10.3976/j.issn.1002-4026.2012.03.024

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       Gait can be captured from a far distance. This paper makes an overview about the origin, history and the state of art of gait recognition. It also summarizes and classifies the existing gait recognition algorithms. Moreover, the paper discusses the development tendency of future study of gait recognition and considers that fusion with other biometrics is the way to make practical use of gait recognition techniques.