西南交通大学学报

Troubles in WastewaterTreatmentTechnologies and Countermeasures

YANG Shun-sheng, YEMei

2001, 14(1): 1-3.

[Abstract](1140)

Abstract:
Some issues encountered in modern wastewater treatment technologies based on activated sludges are summarized in this paper. It is pointed out that with the increasingly high requests on environmental quality from the society, the present technologies cannot fulfill the requirements of water area and water resource protection, and that the function ofwastewater treatment facilities should be extended by confining and killing resistant pathogens. It is necessary to develop newtechnologies as countermeasures to cope with the problems of this kind that may arise in China in the near future. The combination of activated sludges and microfiltration will open a newway in this respect.

The Corrosion and Protection of USAB Reactors

OUYang-feng

2001, 14(1): 5-7.

[Abstract](942)

Abstract:
Because of the chemical and biological reactions in an up-flowanaerobic sludge blanket (USRB) reactor, the inner surfaces of the UASB reactor are easy to corrode, so that the reaction efficiency and the service life of the reactor are decreased and the maintenance cost is increased. In this paper, based on the analysisof the effects of the structure of UASB reactors and the processes of reactions on corrosion, the corrosion mechanism is discussed, and three measures to prevent the corrosion of the UASB reactor are presented,i.e., improvement of the anticorrosion design, application of anticorrosion materials and preservative treatment of the equipment.

Study on Wind Resisting Performance of Long-Span Rigid Frame Bridge in Its Cantilever Construction Stage

ZHENG Shi-xiong, LIAOHai-li, ZHOUShu-hua

2001, 14(1): 8-11.

[Abstract](1614)

Abstract:
In this paper, the study is conducted around a three span prestressed concrete (PRC) continuous rigid frame bridge with a main span of 190 m and consisting of two parallelly-arranged roadway boxgirders. By wind tunnel tests of an aeroelastic model, the aerodynamic coefficients of the front and rear girders are discussed and the effect of horizontal angle of airflowβon these coefficients is also studied. Then, a measurement usingthe thin plate to connecthorizontallythe two parallelly-arranged boxgirders is taken, and its vibration suppressing effect on the wind induced response is analytically discussed. It is shown that for long span rigid frame bridges with two parallelly-arranged roadway box girders, connecting horizontally the two girders in cantilever construction stage can reduce the wind induced horizontal vibration response effectively and easily.

Suppressing the Flutter of Suspension Bridges with Additional Surfaces Attached belowthe Trailing Edge Deck

LIUGao, WANGXiu-wei, QIANG Shi-zhong

2001, 14(1): 12-16.

[Abstract](1430)

Abstract:
A model of self-excited aerodynamic forces acting on a section of bridge deck with additional surface attached belowthe trailing edge is established. In the engineering background of a suspension bridge tender project, taking the bridge and the airflow as a whole system, the effectiveness of the surface in the flutter stability of the system is studied by a multi-mode flutter analysis approach. The analysis shows that the additional surface attached belowthe trailing edge is an effective aerodynamic means for suppressing the flutter of suspension bridges.

Dynamic Analysis ofTrack Wave Propagation Supported on Continuous Elastic Foundations

WANG Ping, LIUXue-yi, LI Cheng-hui

2001, 14(1): 17-22.

[Abstract](1284)

Abstract:
A dynamic analysis model is proposed for the train/track system supported on continuous elastic foundations. The track wave propagation problem under a high-speed train is studied. The influences of some parameters, such as rail surface irregularitywavelength, trackmass, track rigidity and track viscosity, on the critical speed and the track wave propagation are analyzed.

A DeterminationMethod of Soil ShearModulus in Pile Foundation

HUDe-gui, LUO Shu-xue, ZHAO Shan-rui

2001, 14(1): 23-26.

[Abstract](1324)

Abstract:
Based on the comprehensive analysis of currently used three methods for calculating soil modulus in pile foundationi.e., laboratory test, empirical correlation based on previous experience and back- figuringmethod from pile-loading test, a new simple approach to compute soil modulus by back analysis from single pile load-settlement curve is putforward, and charts and formulas are also presented for practical engineering use. Practical example analysis shows that the soil modulus obtained by back analysis from single pile load curve should be used as the parameter for calculating when elastic theory is employed to calculate the pile groups settlement.

Analysis of Seismic Dynamic Response ofHydraulic Turbines under WaterMedium

YUJian-hua, WEI Yong-tao, CAOJian-mian

2001, 14(1): 27-32.

[Abstract](1574)

Abstract:
The seismic response of hydraulic turbines underwatermedium is the typical coupled vibration of liquid-elastic body. To begin with, this paper briefly introduces the theory background and computation method about dynamic behavior of turbines in water, then focuses on discussing the dynamic governing equations of turbine-water system in consideration of the influence of 3 dimensional coupled vibration of liquid-turbine. The time-history analysis is adopted to resolve the equations. Finally, an example of a practical case is given, with the computational result compared against the result obtained without considering the influence of water medium.

Research on Stabilizing the Railway Roadbed with Improved Urea-Formaldehyde-Resin

ZOUBin, SHENRu, QILin-lin

2001, 14(1): 33-36.

[Abstract](1173)

Abstract:
Macromolecule materials are added into urea-formaldehyde-resin to decrease its brittleness and contractility, and increase its water-resistance. The improved urea-formaldehyde-resin in liquid form is injected into soil. With the cross-polymer solidification happening in the soil, the soil is strengthened. It is shown that the strength andwater-resistance of the soil are largely improved through the laboratory test. The field test shows that the mud pumping of roadbed is effectively abated.

Toughening Analysis of Mixed-ModeⅠ-ⅡCracks in Transformation Toughened Ceramics

NIXin-hua, LIUXie-quan, LUXiao-bo

2001, 14(1): 37-40.

[Abstract](1128)

Abstract:
By use of the pressure sensitive stress criterion and the method of weight function, the fracture toughness enhancement induced bymixed modeⅠ-Ⅱcracks in phase transformation toughened ceramics is predicted theoretically. The theoretical expressions for the toughening effects of both the stationary and the steady-state growing cracks are given respectively. Results show that there is a negative effect from the stationary cracks and it increaseswith the increase ofKⅠ/KⅡ, and that the toughening effect of the steady- state growing cracks is not only associated with the modulus of elasticity, the width of transformation area and the transformation volume fraction, but also decreases with the increase ofKⅠ/KⅡ.

Electronic Orbit in the Longitudinal WigglerMagnetic Field

GONGJian-min, TANGJin-sheng

2001, 14(1): 41-43.

[Abstract](964)

Abstract:
The motion equation of electrons in an axial uniform magnetic field and a longitudinal wiggler magnetic field is solved. The strict analytical solution of the electron velocity is derived in the rectangular coordinate system, and the approximate solutions of the electron position in the rectangular or cylindrical systems are also derived. The solutions are verified by numerical simulation, showing that the approximate solutions are fairly accurate.

Analysis of Suspension Force of the EMSMaglevTrain

HUJi-shi

2001, 14(1): 44-47.

[Abstract](1333)

Abstract:
The suspension system is one of the most important subsystems in the maglev train. Its performance will influence the performances of the train directly. The suspension force is the basis of track or bridge girder design and track dynamic analysis. Based on the characteristics of the EMSmaglev train, a mathematical model of the suspension system is presented, and the magnitude of the suspension force and its changes with time are discussed.

Data Transmission by Induction Coupling and Its Application inMaglevTrain Communication System

YANGJian-yong, LIANJi-san

2001, 14(1): 48-52.

[Abstract](1303)

Abstract:
The moment method is applied to two arbitrarily located parallel wires, and the current distribution, self-impedance and mutual-impedance are obtained. An equivalent two-port network is used to get the inductive voltage of each wire. Meanwhile, the variation of coupling strength with distance is analyzed, and it is pointed out that thisway of coupling can be applied to data transmission of maglev train communication system.

Design and Accomplishment of a Real Time Walkthrough System in Virtual Architecture Environment

CHENHua-bin, WANGDan

2001, 14(1): 53-56.

[Abstract](1335)

Abstract:
The application of virtual reality in architecture is a very hot topic. In a walkthrough system, a user can observe the architecture in different view interactively. This paper discusses the characteristics and requirements of a real time walkthrough system. It also discusses the method of modeling and image generation for virtual environments. Meanwhile, the algorithmof object capture according to ray tracing and some convenient interactive tools are presented. The developed system produces a stereoscopic display and has a friendly user interface. Additionally, a specific application example is given based on the campus walkthrough system of Southwest JiaotongUniversity.

CoordinatesTransformation of Engineering Drawings for 3D Reconstruction from Orthographic Views

ZHANGAi-jun, ZHUChang-qian, WANGJi

2001, 14(1): 57-61.

[Abstract](957)

Abstract:
Coordinates transformation of engineering drawings is the basis process for 3D reconstruction from orthographic views. In this paper, amethod is presented for segmenting engineering drawings into views and establishing the corresponding relations of coordinates between them. Two sets of 2.5D coordinate systems are introduced as intermediates to relate the 2D original drawing system to the 3D space projection coordinates, and a formal technique is developed for constructing transformation matrices between coordinates. Coordinate-constraint-based driving relations are established in addition between the views.

Dedicated Short Range Communication and Its Application inTraffic Navigation System

XIENing-bo, GUYan

2001, 14(1): 62-66.

[Abstract](1131)

Abstract:
This paper describes the concept, development, system structure and communication process of the special dedicated short range communication (DSRC). It also analyzes DSRC’s standard, characteristics, and main points of design, and introduces the DSRC’s application in traffic navigation system, with its wire connection being considered at the same time.

A Criterion for EvaluatingTiltingTrains Return Safety

NI Wen-bo, WANGKai-wen

2001, 14(1): 67-70.

[Abstract](1656)

Abstract:
The return angle stiffness of tilting mechanism can be taken to judge the return safety of tilting trains is put forward. Return angle stiffness describes the stability of car-body returning to neutral position when tilting mechanism loses power during the car-body tilting. When the return angle stiffness is positive, the car-body can return to the neutral position under the action ofweight. When the return angle stiffness is negative, the car-body can not return to the neutral position. When the return angle stiffness is zero, the car-body is in a critical position. Therefore, the return angle stiffness can be used as a criterion for evaluating the return safety of tilting trains.

Study on EvaluatingMethods for Human Exposure to Whole-Body Vibration of Automotive Ride

WANLi-xang, XUMing-heng

2001, 14(1): 71-74.

[Abstract](1251)

Abstract:
The characteristics and existing problems of ISO standard 2631 and absorbed power method, which are the currently most popular methods for evaluating human exposure to whole-body vibration in automotive ride, are discussed in detail. The theoretical analysis based on an automotive mechanics model as well as experimental results shows that GB 4970-85, which is based on ISO standard 2631, cannot accurately evaluate human exposure to whole-body vibration in automotive ride. Therefore, this paper develops a new evaluating method, using the accumulated exposure times within the frequently used speeds to evaluate human exposure to whole-body vibration of automotive ride. The evaluation result obtained with this newmethod coincides with the facts well.

On Approximation Properties of the Modified Lupas-Baskakov Integral Operators

TIANJun, WANGLi, GUO Yao-huang

2001, 14(1): 75-79.

[Abstract](1035)

Abstract:
A modified Lupas-Baskakov integral operator, which compounds Lupas operator and Baskakov operator, is introduced in this paper. By analyzing and researching the properties of the modified Lupas- Baskakov integral operators, the paperobtains theVonorovskya asymptotic formula, establishes the saturated order and trifle set of the modified Lupas-Baskakov integral operators, and then sets up the saturation theorem for this kind of operators.

AMultiscale EstimationMethod of Signal Based onMultiple Threshold Processing

HUChang-liu

2001, 14(1): 80-83.

[Abstract](1292)

Abstract:
A multiscale estimation method of signal based on multiple threshold processing is presented. First, the original measurement signal is decomposed with multiscale wavelet transform. Then the detail signals on each scale are further decomposed into sub-detail signals and sub-smoothing signals which are processedwith different thresholds respectively. The smoothing signals on the coarsest scale are processed with Kalman filtering and reconstructed with the detail signal on each scale. At last, the signal estimate value on the original scale is obtained.

ANew Solution to Structural Fuzzy Finite Element Equations Based onMonosource Fuzziness

LIUChang-hong, CHENQiu

2001, 14(1): 84-87.

[Abstract](1159)

Abstract:
Considering that a fuzzy number can be decomposed into a real number and a unit fuzzy number under the monosource of fuzziness, a newmethod to solve fuzzy finite element equations is presented. The procedure of this method in solving a fuzzy finite element equation is firstly to separate the fuzzy factors from the problem, then to solve the finite element equation left, and finally to deal with the result with fuzzy factors. Thus, the method not only can greatly reduce calculatingwork in transforming the fuzzy set into the natural number set, but also can be much greatly convenient for engineers and researchers to study and analyze the structures.

Study on Forecast of the PassengerTraffic Volume ofHigh-Speed Railways

LENGJun-feng, LUFeng-shan, WANGMei-yun

2001, 14(1): 88-91.

[Abstract](1602)

Abstract:
The influence factors of passenger traffic volume and the role of railway passenger transportation in our country are analyzed. Amethod of forecasting the high-speed railway passenger traffic volume in the condition of market economy is put forward,i.e., to forecast the total traffic volume first, then to determine the traffic volume of high-speed railways according to its role in the total passenger transportation market. Specifically, a sample is given to illustrate the proposed forecasting method.

A Study onTransportation Price Regulation Arrangement Based on the Optimal System Profit

SHUAIBin

2001, 14(1): 92-95.

[Abstract](1316)

Abstract:
The shipper and the transportation enterprise are considered as a maximum profit system, but a reasonable and justified transportation arrangement must be searched out in order that both the shipper and the transportation enterprise can reach their maximum profit goals and be accepted by the market. In this paper, based on the incorporation countermeasure theory and aimed at the optimal system profit, the arrangement of transportation enterprise price regulation is researched, and an optimal systemprofitmodel is established and solved with K-T theorem. It is demonstrated by calculation examples that the method has great utility value.

Forecasting the Bid of Engineering Projects with Fuzzy Similar-Priority Comparison

WANG Shun-hong

2001, 14(1): 96-99.

[Abstract](1346)

Abstract:
Bidding is a battle of wits. If a bid is too high, the contract cannot be got, what’s more, the time, manpower andmoneythathave been spentforbidding arewasted. In contrast, ifone bidsmuch lower than his rivals, he obtains the contrast, but he“leavesmoneyon the contrasttable”. Therefore, a good bid must be calculated quantitatively with several different methods, and be selected through comparing the results given by these methods. In this paper a mathematical model based on fuzzy similar-priority comparison is established. It is used to forecast the price of bidding for engineering projects, and its effectiveness is shown by a practical example.

A Synthesized Method for Group sMultiple Objective Decision-Making

ZHOUWen-kun, WUZhen-ye, JUTing-ying

2001, 14(1): 100-103.

[Abstract](1296)

Abstract:
This paper discusses group s multiple objective decision-making problem. Using least square method as a tool and Lagrange function as algorithm, it establishes the optimizationmodel that determine the weight of index by synthesizing subjective and objective information. Meanwhile, this paper gives the fuzzy scale valuation method of determining theweight of the member of a group, providing a simple and practical method for group s multiple objective decision-making.

Study on Flexible Decision-Making-Oriented Organization Design under Agile Manufacturing Environment

CHENXu, WUZhen-ye

2001, 14(1): 104-108.

[Abstract](1261)

Abstract:
Flexible decision-making and its implement under agile manufacturing environment depend on organization for support. This paper beginswith the review and analysis of modern enterprises’organization structures, and then describes the agile manufacturing enterprises’organization structure. Based on this, the authors conduct a study on flexible decision-making-oriented organization design under agile manufacturing environment. In the study, the framework of the flexible decision-making-oriented organization under agile manufacturing environment is put forward, and the organization’s character is discussed. At last, the building of models for flexible decision-making-oriented learning organization under agile manufacturing environment, alongwith the problems that should be paid attention to duringthe process of building a learning organization, is analyzed.

WaveletTransform and Its Application in StockMarket Data Analysis

XIANGXiao-dong, WANG Qing, GUO Yao-huang

2001, 14(1): 109-112.

[Abstract](1342)

Abstract:
Alipschitz exponentα, which reflects the singlaritynature of stock data, is obtainedwithwavelet transform and muti-scale analysis by regarding stock day profit ratio as a one-dimentional time signal.αin this paper is negative, showing that the singularity is more singular than non-continuum. This proves that the variation of stock prices is fractal. At the same time, it is pointed out that when scalesis very big, wavelet transform and multi-scale analysis can remove the up-and-down of stock market data caused by accidental factors and give prominence to primary factors and macroscopic sudden change points. This is important in predicting the variation trend of stock prices frommacroscopic aspect.

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2001 Vol. 14, No. 1