西南交通大学学报

Mechanism of Longitudinal Force Transmission of Welded Turnouts with Different Structures

WANG Ping

2003, 16(4): 371-374.

[Abstract](1337)

Abstract:
The regularity of longitudinal force transmission of welded turnouts with different types of frog and heel is investigated, and the effects of frogs and heels on the force and displacement of the parts of a welded turnout are discussed. The types of frog and heel dicussed include rigid frog, long-wing movable-point frog and short-wing movable-point frog for the former and spacer block and spacing restricting device for the latter. The research result shows that combination of the long-wing movable-point frog and the spacing restricting device is a more reasonable structure of welded turnouts.

Stability Analysis of Jointless Turnout Based on General Formula

TIAN Chun-xiang, WANG Ping

2003, 16(4): 375-379.

[Abstract](1693)

Abstract:
Based on the general formula for the stability analysis of common jointless tracks, the calculation method for the stability of switches of a jointless turnout is put forward. By taking the No.18 turnout in the Qinhuangdao-Shenyang passenger express line as an example, the relationship between the safety coefficient and the wave length, the original plastic camber and the allowable deformation camber is discussed, and a simplified formula for jointless turnouts completely welded is given. The results show that the frog heel of jointless turnouts is easy to lose stability, so the basic verification requirement for the stability of jointless turnouts is suggested as 2 mm for the original elastoplastic allowance camber and 1 mm for the allowable deformation camber.

Process Eigenvalue and Quality of Continuous Flash Welding of Alloy Rail

HUANG Jian-ping, DAIHong, LUO De-yang

2003, 16(4): 380-383.

[Abstract](1343)

Abstract:
Aiming at the problem that the use ofК190Лкwelding machines for welding PD3 60 kg/m rail makes the quality of joints not satisfy the TB/T1632 - 91 standard because of the existence of grey spots in welding joints, the relationship between the quality of rail joints and the eigenvalue of high frequency data at the acceleration stage of rail smelting is analyzed, and the process eigenvalue of rail flash welding is obtained. The research contributes to establishing of the on-line control system of welding quality.

Continuous Calculation of Steady-State Solutions for Railway Vehicle Curve Negotiation

LvKe-wei, ZENG Jing

2003, 16(4): 384-388.

[Abstract](1651)

Abstract:
In order to better understand the mechanical behavior of railway vehicles from a straight track into a curved track, the steady-state solutions(equilibrium points) of a vehicle system are investigated. By using the DERPAR algorithm, the numerical calculation of steady-state solutions of a vehicle system from a straight track through a transitional track to a constant radius curved track is continuously accomplished, and the calculation efficiency is improved. And the steady-state solutions obtained by using the DERPAR algorithm do not contain transient components. Therefore, the influence of the parameters of a vehicle system on its dynamic behaviors can be clearly presented. The research lays the theoretical foundation for the design of the system parameters.

2-D Finite Element Analysis of Prestressed Anchorage Sheet-Pile Wall

FUHai-ying, HE Chang-rong, CHEN Qun

2003, 16(4): 389-392.

[Abstract](1594)

Abstract:
With 2-D finite element method (FEM), the moment and displacement of metope piles, the stress and displacement of interface between anchorage pile and surrounding rock, the settlement and earth pressure of filling soil, and the internal force of anchored cables are calculated in six typical conditions of construction. And the calculation results accord basically with those of field observation and other numerical methods. The results show that the the moment and displacement of metope piles can be decreased effectively by the use of prestressed cables.

Relationship between Moment and Axial Load of Reinforced Concrete Columns Strengthened with Prestressed Struts

JIANG Hua

2003, 16(4): 393-397.

[Abstract](1529)

Abstract:
Based on the basic formula of the limit load-bearing capacity of reinforced concrete (RC) columns strengthened with prestressed struts, the relationship between momentMand axial loadN of a strengthened column is analyzed theoretically, and itsM-Ndiagram is obtained. By comparing with theM-Ndiagram of a common RC column, the result shows that this strengthed method has a reasonal range of application.

Discussion on Some Issues in Theory of Soil Arch

JIAHai-li, WANG Cheng-hua, LIJiang-hong

2003, 16(4): 398-402.

[Abstract](1240)

Abstract:
Some issues in the theory of soil arch in the geotechnical engineering are brought forward, including the forms of spandrel, the shape, geometric parameters and microscopic properties of soil archesetc. From the forming mechanism of soil arches, they are divided into four types,i. e.directly-forming spandrel, induced-friction spandrel, solum-forming spandrel and spandrel with different bases. Based on an engineering instance, some primary views on the geometric parameters of arch shape and arch body are put forward to develop and perfect the theory of soil arch.

Effect of Crowd on Propagation Characteristic of Electromagnetic Waves in Limited Underground Space

SUNJi-ping, ZHANG Chang-sen

2003, 16(4): 403-407.

[Abstract](1521)

Abstract:
By using the finite element method, the effect of crowd on the propagation characteristic of electromagnetic waves in a limited space such as an underground marketplace and an underground platform is investigated. The calculation result shows that crowd s reflectance coefficient increases but the transmission coefficient decreases with the raise of working frequency. The loss of input power in crowd reaches its maximium value when working frequency is between 200 and 300 MHz.

Development of Automobile ABS Controller Based on Threshold Control Method

SUN Ren-yun, GUO Xin, LONG Xing-xian

2003, 16(4): 408-413.

[Abstract](1616)

Abstract:
Through the investigation of automobile anti-lock brake systems(ABS), the controller suitable for hydraulic brake systems is developed with the threshold control method. A proto-type controller has been manufactured and tested on the test-bed. The test result shows that the ABS controller with 80C196KC single chip microcomputer as its key unit can meet the demands of anti- lock brake control, the design of its hardware and software is correct, the determination and processing way of input signals is proper, and the choice of control logic is basically reasonable.

Real Time Simulation System for AC Drive Controller Test

SONG Chang-lin, HUPeng-fei, LI Zhi

2003, 16(4): 414-417.

[Abstract](1627)

Abstract:
An AC drive simulation system, composed of two PCs and two high speed communication cards on the basis of PCI, is presented. Its software is designed to calculate the running parameters of the AC drive system, including transformer, quadrant rectifier, DC circuit, inverter, AC motor and train load. The simulation results are converted with a D/A converter as the sensor signals required by the real time simulation of AC transmission controller

Research on Micro-Computerized Automatic Block System between Railway Stations

ZOU Shao-wen, GUO Jin, YANG Yang

2003, 16(4): 418-422.

[Abstract](1706)

Abstract:
Through analyzing the feasibility of a micro-computerized automatic block system between railway stations based on CAN bus, the plan of its realization is proposed,including the structure, function, working principle and design of the system. In addition, the safety control logic of the system is analyzed.

New Blind Equalizer Based on Filtering in DCT Domain

DENG Xiao-hong, ZHANG Jia-shu

2003, 16(4): 423-427.

[Abstract](1419)

Abstract:
Based on the constant modular algorithm (CMA), a new type of blind equalizer with filtering in discrete cosine transformation (DCT) domain is proposed for the amplitude-and phase- modulated digital communication systems. Computer simulations show that the performance of the proposed blind equalizer is superior to that of the CMA equalizer.

Study on Parallel Algorithm in H.26L Video Encoder

ZHAO Yu-lin, PENG Qiang, WUXiao-xiong

2003, 16(4): 428-432.

[Abstract](1322)

Abstract:
Through the analyses of the parallelism of H.26L video encoder and its performance, several parallel computation schemes are discussed, and a scalable scheme is implemented by using MPI. The experimental results on Dawning-2000 MPP processors show that the H.26L video encoder has a good parallel performance and scalability on slice layers.

Algorithm of Transforming Any Formula in LF(X)into Reducible Form

MENG Dan, SONG Zhen-ming, QIN Ke-yun

2003, 16(4): 433-437.

[Abstract](1190)

Abstract:
In the process of automated reasoning based on the resolution principle by computers, it is necessary to transform any formula into reducible form. The algorithm of transforming any formula in LF(X)is investigated. Based on the introduction of LF(X)and the related concepts, theoretic results for the transformation are proved. Subsequently, the algorithm of transforming any formula in LF(X)into a reducible form is given.

Matrix Characterization of a Type of Disjoin Preserving Operators on Classical Banach Lattices

FENG Ying, CHEN Zi-li, FENG Tian-xiang

2003, 16(4): 438-440.

[Abstract](1319)

Abstract:
The characterization of disjoint preserving operators fromRntoRmis presented by means of the matrix with the property that there is at most one nonzero element in every row. And this result is generalized to the characterizations of bounded disjoint preserving operators from classical Banach latticesc0andlp(1≤p<∞)tol∞,corc0. In addition, the matrix characteristic of bounded disjoint preserving operators on Banach lattices with the disjoint Schauder basis is discussed similarly.

Eigenvector Method of Weight Vector of Generalized Judgment Matrix in Analytic Hierarchy Process

SUNJiang-ming, SUN Li-mei

2003, 16(4): 441-444.

[Abstract](1431)

Abstract:
Through a deep study on the consistency of generalized judgment matrixes, new restraint equations of the weight vector of setS=u1,u2,...,unare obtained. The weight vector can be solved using the equations when the structure matrix corresponding to the set s generalized judgment matrix is irreversible. In addition, a sixth-order generalized judgment matrix is tested randomly, and the result shows that the scope of their application is raised from 66% to 99.5%.

Column Action Method with Orthogonalization for System of Linear Algebraic Equations

YANG Ben-li, ZENG Xian-wen, LI An-zhi

2003, 16(4): 445-449.

[Abstract](1245)

Abstract:
A new SISD iterative algorithm is put forward to effectively solve arbitrary consistent or inconsistent system of linear algebraic equations. It is proved that accurate theoretic or least square solutions of the system can be obtained throughmiterations. In addition, the computational complexity, the numerical stability and the inherent parallelism of the algorithm are discussed.

General Algorithm of Two Kinds of Cubic Spline Interpolation Functions

FENG Tian-xiang

2003, 16(4): 450-453.

[Abstract](1292)

Abstract:
The aim is to solve two kinds of cubic spline interpolation functions in a general algorithm and show the detailed derivation. By combining the spline equations based on the initial conditions for two kinds of splines, the calculation formula for cubic spline interpolation functions is derived in detail without changing the error and convergence. The research shows that two kinds of cubic spline interpolation functions can be solved in this algorithm.

Property of Difference Coefficientσ/μ for Optimal Portfolio and Its Determination

ZHAO Xin-shun, SHI Ben-shan

2003, 16(4): 454-458.

[Abstract](1403)

Abstract:
On the basis of Markowitz s mean-variance model subject to the condition of short sale, the existence and uniqueness of the difference coefficient and its optimal solution are discussed. And under the more practical condition of no short sale, the above properties are proven. The mathematical expression of the coefficient under the condition of no short sale and its solving process are given. Finally, a real example is calculated.

Graphic Analysis of Efficient Frontier of Portfolio

YAO Yuan

2003, 16(4): 459-462.

[Abstract](1531)

Abstract:
Based on the theory ofE-V(expected value-variance) and the mathematical model of the efficient frontier of portfolios, the expected profit and variance of a portfolio including three securities under the different allocation proportions of capital are discussed, and the graphic expressions of lines linking the tangent points of isomean lines and isovariance curves under different conditions are obtained. The research shows that the efficient frontier is composed of a series of parabolic segments connected each other in anE-Vplane and the risk of a compound portfolio is diversified because the variance of the compound portfolio is less than that of a single portfolio with the same variance.

Study on Second-Degree Price Discrimination under Conditions of Oligarchic Competition

GUO Chun-xiang, GUO Yao-huang

2003, 16(4): 463-467.

[Abstract](1268)

Abstract:
The conditions of profit maximizing under the second-degree price discrimination are investigated using the game theory and a quantitative method. Based on the above discussion, the coditions of profit maximizing are generalized. In addition, profit maximizing under the conditions of linear and non-linear demand functions is discussed. The formulas of computing the maximum profit are given.

Analysis of West Coast Port Lockout in USA Based on Dynamic Game Theory

YE Yong, TAN De-qing, LIU Bo

2003, 16(4): 468-471.

[Abstract](1268)

Abstract:
Based on the dynamic game theory and the Leontief model, the event of west coast port lockout in USA is analyzed by applying the Nash equilibrium model, and its possible results are discussed. The research shows that after the struggle between the Stock Workers Union (SWU) and the Pacific Maritime Association (PMA), the Pareto optimality can be approached in a long period. However, with the change of environment and time, this equilibrium will change, and the struggle between the SWU and the PMA may arise repeatedly. Therefore, this kind of events will emerge in the future again.

Research on Benefit Distribution in Signal Control Model

ZHANG Zhi-jue

2003, 16(4): 472-476.

[Abstract](2019)

Abstract:
A multiobjective programming model combining signal control and equilibrium network designs under equity constraint is proposed. With the utility function method, the two-objective upper level optimization is transfered into a single objective optimization problem. In this case, the proposed model becomes a standard bilevel programming model. A penalty function approach and a global optimization method such as the simulated annealing method are used to solve the model.

Forecast of Traffic in Sichuan Province in the Tenth Five-Year Plan

XUE Bo, GUO Qiang, HU Ying-jie

2003, 16(4): 477-481.

[Abstract](1420)

Abstract:
Based on the analysis of factors influencing the traffic and transportation in Sichuan Province, a conclusion is drawn that the level of economic development and its population are the two most important factors. Economic models are built up to forecast the traffic in Sichuan Province in the 10th Five-Year Plan, and the general testing process of these models is presented.

Model for Attractive Area of Urban Rail Transit Stations and Its Algorithm

LIUHui-min, LIU Wei-hua

2003, 16(4): 482-485.

[Abstract](1503)

Abstract:
The present researches on the attractive area of urban rail transit (URT) stations are analyzed, and their shortcomings are pointed out. On the basis of some rational hypotheses, the method to determine the attractive area in single lines is discussed, a model for the attractive area is set up, and its algorithm is given. In addition, its application process in URT plans is introduced by using an example.

Analysis of Drivers Security Reliability Based on Error Possibility

XUJie, DU Wen, MA Guo-zhong

2003, 16(4): 486-590.

[Abstract](1469)

Abstract:
Error possibility, a fuzzy method evaluating man-made errors, is adopted to analyze the reliability of drivers driving instead of error rate used in the present analyses. And man-made errors are analyzed and evaluated based on fault tree. A conclusion is drawn that the error potentiality of a top event is closely related to the error possibility of continuous sub-events,i.e.drivers fail is caused by a series of their errors.

Determination of Nitrite in Water with Flow Injection Chemiluminescence Method

GONG Zheng-jun, ZHANG Zhu-jun

2003, 16(4): 491-493.

[Abstract](1313)

Abstract:
A new chemiluminescence method for the determination of nitrite in water is presented. This method is based on nitrite reaction with hydrogen dioxide solution with catalyst acid to create peroxynitrous acid. Peroxynitrous acid reacts with alkaline solution of luminol, producing chemiluminescence. The linear range for nitrite is 3.3×10-3to 3.3μg/mL with a detection limit of 1.6×10-3μg/mL, and the relative standard detection is 1.03% for 0.17μg/mL NO-2and 4.38% for 0.017μg/mL NO-2. This method has obtained satisfactory results in the analysis of natural waters.

Synthesis of Tetra-Imidazolylmethyl Bi-Phenol Compounds

LU Shu-he, LIUZhi-chang, LIUXiao-xia

2003, 16(4): 494-496.

[Abstract](1055)

Abstract:
Tetra-imidazolylmethyl bi-phenol compounds (3a,3b) are efficiently synthesized and structurally confirmed. 4, 4 -dihydroxydiphenylpropane and 4,4 -biphenol are respectively treated with paraformladehyde to give tetra-hydroxyl derivative (2a,2b). Treatment of (2a,2b) with imidazole at 130 to 140℃and 160 to 170℃in DMF gives the corresponding tetra-imidazolylmethyl bi-phenol (3a,3b). The chemical yields of 3aand 3bare 57% and 59.3% respectively. Tetra- imidazolmethyl bi-phenol compounds obtained have been confirmed by MS,1HNMR, IR measurements and elemental analyses.

Experimental Investigation on Vibration Performance of Polyurethane Foam Plastic

TANG Yi-ke, GONG Xian-sheng, GU Qian-kun

2003, 16(4): 497-500.

[Abstract](1377)

Abstract:
An experimental device of the vibration performance of foam plastic was set up. The vibration test of a reinforced plastic material was carried out. Experimental results show that the vibration performance of this foam plastic material has relation not only to vibration amplitude but to exciting frequency. The restoring force of the foam plastic material is influenced by exciting frequency, vibration amplitude and deformation history. The foam plastic material has a nonlinear hysteretic characteristic. In vibration conditions, stiffness and damping characteristics of the foam plastic material are nonlinear. The research lays a foundation for modeling and parameters identification, dynamic design and dynamic optimization of the vibration-isolation material.

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2003 Vol. 16, No. 4