西南交通大学学报

An Automatic Optimization Method for Designing the Initial Horizontal Alignment of New Railway Lines

YISi-rong, ZHANGJia-ling, DENG Yu-cai

2002, 15(1): 1-4.

[Abstract](1440)

Abstract:
In order to obtain a reasonable initial horizontal alignment scheme for optimization of a new railway line quickly, the procedure of the initial horizontal alignment is divided into two stages: 1) to find a chain-linked fold line fromthe centerline ofthe route selected by aerial surveying alignment, based onwhich a straight-curve-straight initial horizontal alignment is then obtained, 2) to generate the initial horizontal alignment scheme of the new railway line by optimization design. The method proposed in this paper has been successfully applied to“the intelligent CAD system for railway location”.

Aerodynamic Effect of Large-Scale and High-Speed Landslide

LIUYong-jiang, HUHou-tian, BAI Zhi-yong

2002, 15(1): 6-9.

[Abstract](1509)

Abstract:
On the basis of aerodynamics, the aerodynamic effect of landslide body flying at a high speed in the air is studied, and the differential equation of move is elicited. According to the obtained equation, the duration time and distance of landslide flying can be figured out. The results are significant to prevent and reduce landslide disasters.

A Quantitative Method for the Coupling Effect of Temperature Fields and Stress Fields in Rock Mass

HE Yu-long, YANGLi-zhong, YANGMing

2002, 15(1): 10-13.

[Abstract](1427)

Abstract:
The coupling mechanism between temperature fields and stress fields is briefly analyzed, and a quantitative method for calculating the coupling parameterPTCis introduced in detail based on the thermo- elasticity effect and the thermal diffusion equation. The proposed quantitative parameter is used to evaluate the thermo-elasticity coupling effect. The thermo-elasticity coupling effect of several kinds of common rocks are calculated, with a result showing that usually the value ofPTCis of the order of 10-3. In the mean time, a preliminary discussion on the practicability and significance of the dimensionless parameterPTCin engineering application is made.

Study on the Criterion of SMA Framework

LUYong-gui, ZHAOKe

2002, 15(1): 14-18.

[Abstract](1794)

Abstract:
Fromthe traditional pointof view, the criterion of framework forSMA(stone matrix asphalt) mix is thatVDRC(the voids in coarse aggregate on the dry rodded condition) must be larger thanVMix(the voids in coarse aggregate of mix). However, there are several facets, such as the compaction method, the measuring precision, and the density conversion for calculating the voids in coarse aggregate, which could cause system errors. Consequently inmany casesVDRCis always largerthanVMix, and the optimal gradation can not be realized. The test results showthat theVMixwhich is calculated with the bulk density measured by calipers is fairly reasonable. There is a turning point in the curve for theVMixversus the percentage of the fine aggregate passing the 4.75 mm sieve. It is feasible to use this turning point to evaluate the formation of coarse aggregate skeleton in a SMAmix.

Mechanical Properties of Roller Compacted Concrete

DENG Rong-gui

2002, 15(1): 19-15.

[Abstract](1255)

Abstract:
To investigate the mechanical properties of the roller compacted concrete (RCC) of a high arch dam in Minjiang river catchment, the RCC samples drilled out of the damwere tested under routine triaxial pressure and direct shearing loads. According to the test data, the properties of deformation, strength and fracture of the RCC under routine triaxial pressure and direct shearing loadwere analyzed in detail, and the constitutive equation ofRCCwas derived. The results showthatthe tangentmodulus of elasticityof the RCC under triaxial pressure is comparatively high and the compressive strength is relatively low. There is a large difference between the shear strength of RCC under routine triaxial pressure and that under direct shearing load.

Research on Technical Conditions of Chromium-Containing Residue as Cement Mineralizer

FUYong-sheng, OUYANGfeng

2002, 15(1): 26-28.

[Abstract](922)

Abstract:
The best technical conditions of chromium-containing residue acting as cement mineralizer are obtained in pilot production. The proper additive ratio of chromium-containing residue in producing cement in a vertical furnace is 2%; and the temperature should be controlled at 1 300℃to 1 400℃. With this technique, the cement strength is improved by 6% to 10%, and the reduction ratio of Cr6+is 96.2%.

Pozzolanic Activity and Morphology Features of Concrete Admixture of Lithium-Salt Residue

XIAChun, LIUHao-wu, YANQi-xiang

2002, 15(1): 29-34.

[Abstract](1312)

Abstract:
A newtype of concrete admixture is fabricated by mixing lithium-salt residue (LSR) and fly ash in a certain proportion. Experiments on this admixture show that: the addition amount of LSR affects the pozzolanic activity of the concrete admixture and the strengths of concrete aged 7 d, 28 d and 60 d respectively. Moreover, some modern test technologies, such as scanning electron microscopy and X-ray diffraction, are used to studythe pozzolanic activityof the concrete admixture and the morphology features of hydrated cement in their initial and later stages. The optimum content of LSR in the compound admixture is obtained.

Exact Solutions of Evolution Equation for Generalized Thermodynamic Coordinates of Viscoelastic Medium

DAIGuang-ze, XIA Yan, ARAKIShigetoshi

2002, 15(1): 35-39.

[Abstract](1184)

Abstract:
It is obvious that the exact solutions of the evolution equation, which is derived by regarding the deformation process of viscoelastic materials as an irreversible thermodynamic process, depend verymuch on the properties of their coefficient matrices. These matrices are usually affected by the nature of the generalized thermodynamic coordinates, which leads the solutions for the generalized thermodynamic coordinates to that: (1) the term proportional to time will arise when only one neutrally stable equilibrium coordinate exists in the coordinates participating in the entropy production; and (2) the generalized thermodynamic forceswill be replaced by the equivalent generalized thermodynamic forceswhen parts of the observed generalized thermodynamic coordinates participate in the entropy production.

Random Vortex Method for Two-Dimensional Flow past Bluff Body

LIXiao-yu, SUO Qi-feng, QIANG Shi-zhong

2002, 15(1): 40-43.

[Abstract](1237)

Abstract:
The theory of stochastic differential equation is employed in the discrete vortex method to solve the problem of two-dimensional flow past a bluff body. The Von Karman Vortex Street, the distribution of radial velocity on the wake axis, and the coefficients of lift and drag are obtained by the present method in the calculation about two-dimensional flow past still cylinder at several Reynolds numbers. The obtained results are in good agreementwith those reported in the published literatures.

Hydrogenerator Rotors: Zero Frequency of Torsional Vibration and Resonance

CHENGui-qing, YANG Yi-ren, QIUJia-jun

2002, 15(1): 44-48.

[Abstract](1387)

Abstract:
The clearance energyofmagnetic field and electromagnetic stiffness of a large hydrogenerator unit are obtained, the formula for solving the whole torsional natural frequency of the hydrogenerator rotors is derived, and the zero frequency of torsional vibration under the rated running condition is calculated The change of zero frequency with the exciting current and the active power, and the magnitude-frequency character of resonance when zero frequency approximates to the working frequency, are analyzed.

Experimental Study on Explosive Technology to Prepare Hydroxyapatite Coating on Titanium

ZHOUYou-long, HUANGNan, ZHANGJi-chun

2002, 15(1): 49-52.

[Abstract](939)

Abstract:
Hydroxyapatite (HA) coating on titaniumwas prepared by. Explosive temperature, pressure and velocitywere obtained with thermodynamics and the detonation wave theory, and the experimental results were also analyzed with the detonation wave theory. Because of curvisurface wave, the coating was not uniform, and there was distortion on the workpieces. Only the Al-HA composite coating was comparatively uniform. The explosive technology provides a newway to prepare stable hydroxyapatite coating on titanium

Travel Cost Analysis of Air Transportation

SUNHong

2002, 15(1): 53-56.

[Abstract](1349)

Abstract:
In order to improve the competitive power of air transportation, it is necessary to strengthen the analysis of market demand, especially on the choice behavior of passengers between air transportation and highway or railway transportation. In this paper, a mathematical model of travel cost is established to quantitatively describe the choice behavior of passengers, in which the major factors considered by passengers in their travel method choice, such as money, time, convenience and comfort, are expressed in the formof cost. Generally speaking, the higher the travel cost of a travel method is, the less possible it is to be chosen by passengers. A comparison between the costs by different travel methods is made on two typical air routes,i. e., Beijing to Shanghai and Chengdu to Chongqing. Finally, the methods for decreasing the travel cost of air transportation are briefly discussed.

Cost-Benefit Analysis of GNSS Non-precision Approach on Feeder-Route Aerodromes

ZHANG Fei-qiao, ZHANG Ze-long

2002, 15(1): 57-60.

[Abstract](1299)

Abstract:
Global navigation satellite system (GNSS) is the trend of development and application of CNS/ ATMtechnology in civil aviation. The cost-benefit analysis methods for the GNSS non-precision approach and the traditional non-precision instrument approach are given as reference formiddle or small feeder-route aerodromes. The investment cost of constructing GNSS non-precision approach is discussed in detail, and a calculation method forthe economic benefitgrowth ofGNSS non-precision approach relative to the traditional non-precision instrument approach is put forward.

Air Traffic Flow Management by Use of Flight Routes and Aerodrome Areas as Nodes

ZHANGXin-jun, YEHuai-zhen

2002, 15(1): 61-64.

[Abstract](1485)

Abstract:
Air traffic flowmanagement is a systematic programming management for solving air traffic jams. In this paper, by using flight routes and aerodrome areas as the nodes to control air traffic flows, an integer programming model of air traffic flowmanagement based on holding on ground is established. The effects of various constraints are discussed overall in the model. A practical example proves the effectiveness of this model in solving air traffic jams.

Toll Diversion and Rational Toll Rate of Highways

CHUKe-bo

2002, 15(1): 65-67.

[Abstract](1167)

Abstract:
The toll rate directly influences the traffic volume on toll highways, and hence influences the benefits of the projects. After an analysis of the factors affecting the route choice of cars, the concept of perceived operating cost is put forward. Amethodology for rationally setting the toll standard of highways is proposed based on the study on toll diversion model and its application, and illustrated by a practical example. Being a theoretical basis forsetting a rational toll standard, the proposedmethodology is to provide decision support information for the construction of toll highway projects.

Network Model and Algorithm for Freight Train Marshalling Plan

LI Ying-hong, WUShi-gui, PENG Qi-yuan

2002, 15(1): 68-71.

[Abstract](1734)

Abstract:
This paper begins with a description of the complexity of making up freight train marshalling plans. It is pointed out that an exact and rational result can be obtained by joint optimization of car flow routing and marshalling plan. Then, a mathematical model is built by transforming the problem of freight train marshalling plan into a calculation problem aboutmarshalling network graph, tominimize the total cost of car flows within the railway network. Finally, the algorithm of this model is approached.

A Simulation System for Rolling Freight Cars at the Rear of Marshalling Yard

MIJie, HAOJing-ru, YAO Wen-xi

2002, 15(1): 72-76.

[Abstract](1589)

Abstract:
In order to exactly describe the motion regularity of rolling freight cars at the rear of marshalling yard, and provides a basis for scientifically and rationally planning the installation of anti-rolling devices. The various longitudinal forces existing in the rolling course of train set are analyzed based on the longitudinal dynamics of train. The object-oriented modularization design method is used to develop simulation software for rolling freight cars at the rear of marshaling yard, in which real-time simulation of rolling freight cars in various operating conditions is realized..

An Analytic Method for the Synthesis of Spatial 5S-S Parallel Robot Mechanism

LILi, LIUZhao-hui, CHEN Yong

2002, 15(1): 77-80.

[Abstract](1236)

Abstract:
Groebner base is an important concept and a powerful tool for solving the problems in nonlinear polynomial algebraic systems. In this paper, an algebraic method based on Groebner bases is applied to the synthesis of a spatial 5S-S parallel robot mechanism for the first time. The symbolic triangular Groebner bases,i. e., the analytic solution of the problem of a rigid body with six given precise points, are obtained.

The Design and Simulation of Electric Vehicle Drive System with High Frequency AC Pulse Density Modulation

MAXian-min, CHENQuan-shi

2002, 15(1): 81-84.

[Abstract](1390)

Abstract:
A novel drive system with high frequency AC pulse density modulation for electric vehicles is proposed, and its operation principle and control method are studied in detail. Theoretical analysis shows that the suggested system is characterized by high energy density, small volume and high efficiency, which are verified by a computer simulatio

Evaluation of Performance of Cold Air Distribution Diffuser

CAIDe-yuan, GUAN Yan-zheng, ZENG Yan-lin

2002, 15(1): 85-89.

[Abstract](1189)

Abstract:
The performance of a windmill-centrifugal fan induction-diffuser is analyzed through experiments and numerical simulation. It is shown that this type of diffuser has a high induction ratio, and can operate well in a large variation range of airvolume. Therefore, it can provide a fairly uniformdistribution of airflow and temperature in the working area of an air conditioning room. It is concluded that by using this type of diffuser, a comfort thermal environment can be obtained in the cold air distribution systemwith ice storage.

The Properties and Application of a Mixed Operation in Evaluation Lattice

WUHong-bo, WENQiu-mei

2002, 15(1): 90-4.

[Abstract](1154)

Abstract:
TheR0-algebra, implication lattice and basic logic algebra are studied. The properties of a mixed operation ∶a b= (a→ b) in evaluation lattice, especially its properties inR0-algebra, are discussed. Akind of filter is derived by use of this mixed operation, with some interesting results being obtained. Thiswork can deliverreference and help forfurtherresearchonR0-algebra and evaluation lattice.

A Method to Calculate the Minimum Path Sets between Two Nodes in a Network

CHENG Shi-juan, HEPing

2002, 15(1): 95-98.

[Abstract](1181)

Abstract:
Based on connectionmatrix, this paper presents a newmethod to calculate the minimumpath sets between two nodes in a network, and gives a precise proof of it. By this method, the rows corresponding to the input nodes and the columns corresponding to the output nodes in the general connection matrix of the network are eliminated, and the path calculation in the network is transformed to the operation of connection matrix determinant. The method is applicable to any oriented, nonoriented or mixed networks.

A New Algorithm for Fuzzy Multi-objective Prediction Control Based on Satisfactory Optimization

FENGXiao-yun, ZHAO Dong-mei, LI Zhi

2002, 15(1): 99-102.

[Abstract](1534)

Abstract:
A new method of optimization control is proposed, in which the traditional optimum control is substituted by satisfactory optimization control in performance optimization of fuzzymulti-objective prediction control. By studying the single step prediction model of fuzzy multiple objectives, an algorithm of satisfactory optimization for a control objective is presented. On the basis of this, a new algorithm for fuzzy multi-objective prediction control is put forward based on satisfactory optimization.

Reliability and Security Analysis of 3-Module Redundancy System with One Maintainable Unit

WANGLi-hua, XUZhi-gen, WANG Chang-lin

2002, 15(1): 103-107.

[Abstract](1562)

Abstract:
The reliability and security of 3-module redundancy systems are derived in detail on the basis of Markov model, in which the influences of faulty coverage ratio and maintenance rate are considered. The differential equation group for solving the reliability and security of the system is presented, and the influences of faulty coverage ratio and maintenance rate on the reliability and security of the system are simulated withMATLAB.

Application of Microcomputer to Economical Four-Stage Semi-control Rectification System

MENG Yu-fa, GONG Bang-ming

2002, 15(1): 108-120.

[Abstract](1477)

Abstract:
The status in quo of the economical four-stage semi-control commutation control system for electric locomotives in China is analyzed. Aiming atthe existing problems, a digital control systembased on 8751 singlechip microcomputer is designed. It is a high performance digital controller, which possesses a high resolution digital trigger, high precision synchronous interrupt pulses, and a high precision fast A/D converter.

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2002 Vol. 15, No. 1