交通运输工程学报

Effect of yaw dampers on locomotive riding comfortability

LIU Jian-xin, WANG Kai-yun

Abstract: In order to effectively control the severe sway and improve the riding comfortability for speed-raised locomotive, the effects of the damping parameters, unloaded speeds and working conditions of dampers on locomotive comfortability were analyzed by vehicle and track coupling dynamics.Analysis result shows that the working conditions of dampers have much effect on the running quality of locomotive, so it must be ensured that all of dampers are in work when locomotive runs on railway; it can improve locomotive riding performance to choose proper unloaded velocities of dampers; the bigger the damping values of all dampers are, the more comfortable locomotive is.More>

2006, 6(4): 1-4.

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Finite element analysis of composite structure of eccentric beam and plate

XIE Su-chao, TIAN Hong-qi, YAO Song

Abstract: In order to deal with the eccentric connection problems of plate and beam reasonably in the structural analysis of vehicle, the constraint equations to the correlative nodes of plate and beam were involved in their balance equations, based on the theories of penalty element method and Lagrange multiplier method, which can solve the contribution problem of the eccentric connection to unitary stiffness matrix.A finite element program was worked out to solve the static intensity calculation problem of composite structure.Numerical computation result shows that the results of the two methods are both close to those obtained by finite element software ANSYS 9.0, the maximum errors of displacement and stress are respectively less than 1% and 2%, it indicates that the two methods are effective on dealing with the composite structure of plate and beam.More>

2006, 6(4): 5-9.

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Calculation method of wheel-rail contact relation

NI Ping-tao, WANG Kai-wen, ZHANG Wei-hua, CHI Mao-ru

Abstract: In order to reflect really wheel-rail contact states, the displacement, bouncing, yaw, roll of wheelsets and the displacement, bouncing, roll of rails were considered, wheel-rail normal forces at two contact points were respectively calculated by nonlinear Hertz contact theory, the minimum gap between rail and wheel was calculated by trochoid method and divided rail outline method, so that wheel-rail real contact states, such as natural one-point contact, nonnatural one-point contact, two-point contact and wheel complete lift, were easily judged.Simulation result of wheel-rail contact relation shows that judged wheel-rail relation accords with real wheel-rail contact relation, the method is feasible.More>

2006, 6(4): 10-13.

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Influence of non-steady state loading on two-dimensional wheel-rail pure rolling contact stresses and deformation

WEN Ze-feng, JIN Xue-song, XIAO Xin-biao

Abstract: In order to study the relation between wheel-rail corrugation surface and non-steady state loading, a two-dimensional elastic-plastic model of repeated frictionless wheel-rail rolling contact was established, the effects of the fluctuating amplitude coefficient of normal contact pressure on the residual stresses, strains and displacements of rail were analyzed.An advanced cyclic plasticity model developed by Jiang and Sehitoglu was used, material ratchetting effect was considered, non-steady state rolling contact was only considered as the harmonic variation of normal contact pressure, repeated rolling contact was simulated by the multiple translations of varying semielliptical Hertzian pressure distribution across elastic-plastic semi-infinite half space.Analysis result shows that non-steady state normal contact pressure results in a wavy rail surface profile with the same wavelength as the pressure; as rolling time increases, rail residual stress increases, but tends to stabilize, rail residual strain also increases, but ratchetting rate decays; when preassure fluctuating amplitude coefficient increases, rail residual stress in rolling direction below the trough and crest of wavy deformation increase respectively, rail residual stress in axial direction, rail residual shear strain and surface displacement in longitudinal direction below the trough increase respectively, but rail residual stress in axial direction, rail residual shear strain and rail surface displacement in longitudinal direction below the crest decrease respectively, the wave depth increases.More>

2006, 6(4): 14-19.

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Calculation method of wheelset natural frequency based on transfer matrixes

MI Cai-ying, AN Qi, LI Fei

Abstract: Vehicle wheelset natural frequency was analyzed by transfer matrixes, according to the characteristic of wheelset structure, vehicle wheel and axle-box were simplified to collective quality and inertia moment, and wheelset axle was simplified to non-uniform Temoshenko beam including collective quality and inertia moment, then wheelset vibration transfer matrix was set up, wheelset natural frequency was calculated by solving wheelset frequency equation using Newton-Raphson method.In wheelset design stage, its effects on wheelset stress condition and the vibration perporties of vehicle system and track system were analyzed.In comparison with FEM, the relative error of wheelset natural frequency is less than 10%, the calculation method can satisfy the need of project design.More>

2006, 6(4): 20-22.

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Structure parameter influence of slab track for high speed railway on wheel-rail noise

XU Zhi-sheng, ZHAI Wan-ming

Abstract: In order to decrease wheel-rail noise, wheel-rail noise predicting model and STTIN software were put forward, the structure parameter influence of slab track on wheel-rail noise was analyzed.It is pointed that wheel-rail noise rises while the stiffness of rail pad is higher than 200 MN·m^-1, and the damping of rail pad drifts off the value of 100 kN·s·m^-1, wheel-rail noise is almost indeclinable when modifying the stiffness of slab pad, but it decreases when increasing the mass of slab.The result shows that the stiffness and damping of rail pad are the key factors influencing wheel-rail noise, the mass of slab is the secondary factor, and the stiffness of slab pad primarily has no influence on wheel-rail noise.More>

2006, 6(4): 23-26.

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Influence of mix-designed parameters on frost thaw resistance of high performance concrete

GAO Lei, CHEN Shuan-fa

Abstract: Taking water to binder ratio, fly ash percentage and sand ratio as mix-designed parameters, the influences of the parameters on the frost thaw resistance of high performance concrete (HPC) were studied with orthogonal experiments, the loss rates of bending strength and quality were calculated after 300 cycles of rapid freeze-thaw test, and their maximum difference binder ratio and variance were evaluated.The result shows that water to binder ratio has great influence on the frost thaw resistance of HPC, while fly ash percentage and sand ratio have little influence on the frost thaw resistance; the loss rate of bending strength is more sensible to freeze-thaw test than the loss rate of quality, so it should be used as the evaluation index of HPC.More>

2006, 6(4): 27-31.

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Effect of fiber contents on toughness of polyester fiber asphalt concrete

GUO Nai-sheng, ZHAO Ying-hua, SUN Lue-lun

Abstract: In order to study the deformation of polyester fiber asphalt concrete with different fiber contents by splitting test, Marshall samples of asphalt mixture, with fiber quality contents of 0, 0.15%, 0.20%, 0.25% and 0.30%, were tested by MTS810 at (15 ℃, ) a non-dimensional toughness index was induced in order to evaluate the deformation performance of polyester fiber asphalt concrete.It is found that polyester fiber doesn't evidently change the splitting strength, but it significantly enhances the toughness and deformation resistance of asphalt concrete, the proposed toughness index can properly evaluate the deformation resistance of polyester fiber asphalt concrete, and the optimum fiber content is about 0.20% according to the toughness index and the splitting strength.More>

2006, 6(4): 32-35.

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Performances of new type asphalt additive TPS

ZHANG Rui, HUANG Xiao-ming, HOU Shu-guang

Abstract: To study the field performances of new type asphalt additive TPS, penetration test, ductility test, softening point test, consistency test, direct tension test, bending beam rheometer test and elastic recovery test were done to asphalt binders modified with TPS, and rutting test, fatigue test, bending beam damage test, moisture damage test were done to asphalt mixtures modified with TPS.The comparison of the test results and the performances of SBS modified asphalt mixture indicates that TPS can improve not only the temperature sensitivity, high temperature stability, low temperature performance of asphalt, but also the high temperature stability, low temperature anti-crack performance, anti-fatigue stability, moisture stability of asphalt mixture, asphalt mixture modified with TPS have good field performances.More>

2006, 6(4): 36-40.

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Permeability coefficient and test method of porous concrete

ZHENG Mu-lian

Abstract: In order to effectively measure the permeability coefficient of porous concrete, the physical foundation of its permeability coefficient was analyzed, an ascertaining method of Darcy law applicable range to porous concrete was put forward.According to the measurement principle of constant head permeability test, a simple and practicable constant head permeameter of porous concrete was developed on the basis of considering the factors of side wall leakage, sleeve dimension and piezometer location.Besides, the factors of test piece status and water were analyzed, the test operation and data processing method of porous concrete were proposed, and the permeability coefficients of different porous concretes were tested.Test result shows that porous concrete has fine drainage performance, its permeability coefficient is more than 10 cm·s^-1; there is power exponent relationship between its permeability coefficient and effective porosity, their correlation coefficient is 0.9681.The result indicates that the method can test the permeability coefficient of porous concrete accurately and effectively.More>

2006, 6(4): 41-46.

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New load-transfered evaluating method at doweled joint of rigid pavement

CHEN Fei, ZHANG Ning, LIN Ya-ping, QIAN Zhen-dong, HUANG Wei

Abstract: Based on considering dowel loosened quantity, a doweled joint model of rigid pavement under repetitive loading was formed, a new method figured by the first critical load of load-transfered condition was put forward to evaluate load-transfered capacity at joint, the effect of load size, load position and dowel loosened quantity on joint load-transfered capacity was studied, the applicability of existing load-transfered index figured by direct deflection ratio under repetitive loading was analyzed, and compared with that of new load-transfered index which took dowel loosened quantity into consideration.It is found that the relationship between load and deflection near joint under repetitive loading is subsection linear character, there exists several levels of critical loads, the error between field test load and calculated first critical load in load-transfered condition is only 4.2%;direct deflection ratio changes from 57.3% to 71.5%, and load-transfered capacity with dowel loosened quantity changes from 0 to 51.9% after 4×10⁴ times repetitive loading.Analysis result shows that the model is reliable, the new method can actually reflect the load-transfered status of doweled joint in rigid pavement under repetitive loading.More>

2006, 6(4): 47-51.

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Effect analysis of percussive compaction and dynamic compaction on roadbed reinforcement

SHI Gang, ZHI Xi-lan, XIE Yong-li, LIU Yi-lin, ZHAO Guang-hai

Abstract: The highway bases of one section in the loess area of Shaanxi province were consolidated by percussive compaction and dynamic consolidation, the physical force indexes (dry density, constrained modulus and collapsibility coefficient) in different depths and the microstructure features of the loess were analyzed by soil engineering test in laboratory and original test, the results of plate loading test, cone penetration test and compressuremeter test were compared, the intensity forming mechanism of the loess roadbed and the changes, effects and valid influence depths of foundation bearing capacity in the loess area were analysed.Analysis result shows that the valid influence depth of dynamic consolidation ranges from 1.0 to 2.0 m, and successive, even, solid reinforcement layer is formed in the range between 0 and 1.5 m; for percussive compaction, the valid reinforcing depth reaches 4.0 m, the valid influence depths varies from 5.0 to 6.0 m, and the collapsibility is eliminated effectively in reinforcing depth. (2 tabs, )More>

2006, 6(4): 52-56.

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Auto-leveling control system of paver based on CAN bus

WANG Xin, GOU Wei-cheng, JIAO Sheng-jie

Abstract: In order to improve the smoothness of road paving, a multi-point (multi-probe) non-touching auto-leveling control system based on CAN (control area network) bus was developed, the structure of the system, the circuit of CAN node and the main flow charts of CAN node software were given, multi-filtering algorithm was employed to eliminate the wild data during road paving process, so that the disturbance attenuation performance of the system was improved.Comparison test result shows that the leveling effect of multi-probe is more effective than single-probe.Compared with touching auto-leveling system, the paving smoothness of intermediate surface layer is increased by 3.2%, and upper surface layer by 7.8% with the system.More>

2006, 6(4): 57-61.

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Braking torque computation method of permanent magnet retarder

HE Ren, ZHAO Wan-zhong, NIU Run-xin

Abstract: In order to optimize the design parameters, and improve the braking performance for permanent magnet retarder, its magnetization vector distribution was analyzed by complex vector method, its eddy loss was calculated in rotor, the computation formulae of its braking torque were derived in order to reflect the mutual relations among braking torque and different design parameters.The comparison of bench test result and computation result shows that the maximum error is less than 6%, so the computation formulae are feasible, and they are approximate to compute retarder braking torque.More>

2006, 6(4): 62-65.

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Neural network control method of automotive semi-active air suspension

ZHU Si-hong, LU Bao-zhan, WANG Hui, ZHANG Ying, HE Liang

Abstract: In order to improve the control effect of vehicle semi-active suspension, adaptive neural network control method was developed, the air pressure of spring was taken as controlled object, the computer simulation and experiment of body plumb acceleration, suspension dynamic deflection and wheel dynamic load with semi-active air suspension under the excitations of different road surfaces were studied, the control result of neural network control suspension was compared with the control effect of passive suspension.Under the excitations of white noise roads and lower frequency sinusoid roads, the result shows that the semi-active suspension with the method not only markedly reduces body plumb acceleration, wheel dynamic load, suspension dynamic deflection, the decreased range is from 16% to 85%, but also improves automotive driving stability, riding comfortable performance and running security.More>

2006, 6(4): 66-70.

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Integrated robust control system of rudder and fin

ZHANG Xian-ku, YANG Yan-sheng, GUO Chen

Abstract: In order to improve the safety and comfort of ship navigation, a kind of rudder-fin joint control system was designed to make ship have good course-keeping and roll-damping effects, a closed-loop gain shaping algorithm for multi-input multi-output (MIMO) system was presented by constructing the transfer function matrix of the closed-loop system according to prior knowledge, four parameters with engineering meaning, such as bandwidth frequency, high frequency asymptote slope, the largest singular value and the peak value of closed-loop frequency spectrum, were used to construct the matrix.The designed algorithm was applied to a rudder-fin joint control system, its simulating curves were obtained using Simulink.Simulation results show that the controll system has well control performances on course-keeping and roll stabilization, the average roll angle range is from +2° to-2°, and the maximum roll angle is 4°.More>

2006, 6(4): 71-74.

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Increment feedback control algorithm of ship track based on nonlinear sliding mode

BU Ren-xiang, LIU Zheng-jiang, LI Tie-shan

Abstract: The straight-path tracking problem of underactuated ship with state constraints and actuator saturation was analysed, a nonlinear control algorithm was developed by integrating increment feedback and dynamic nonlinear sliding mode based on an iterative designing procedure, so that the problems of static error caused by constant disturbances and chattering in variable structure control were circumvented, the heading and the cross-track error of ship were stabilized without necessary estimating the parametric uncertainties and disturbances induced by wind and current.Numerical simulation result of training ship "Yulong" shows that the controller is robust to systemic variation or outside disturbances and easy to adjust due to the clearness of parametric functions.More>

2006, 6(4): 75-79.

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Defined method of hydraulic parameter of rapids abating

CAO Min-xiong

Abstract: In order to directly define the hydraulic parameter of rapids abating, power method was suggested according to the comparison of ship effective power and water flow power in rapids reach, and was verified by theoretic analysis and the test data of remote-control model while ship ascending rapid in generalized rapids reach.It is pointed that ship effective power was larger than water flow power while ascending rapid, the difference range increases with the sailing speed of opposite bank; while ship failed to ascend rapid, ship effective power was lower than water flow power.Analysis result shows that the method can directly determine the hydraulic parameter of rapids abating according to hydraulic conditions and the performance data of different ship types, can satisfy the future design of waterway development, and may be applied in the regulation design of rapids channel.More>

2006, 6(4): 80-83.

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Planning algorithm of tactics flight path

ZHANG Yong-fang, ZHANG An, ZHANG Zhi-yu, ZHANG Jiu-long

Abstract: In order to find optimal flight path with certain constraints, a trajectory planning algorithm of tactics flight path based on Voronoi diagram was presented, the function of threat cost was formulated, reference flight path consisting of a series of beeline segments was generated by decomposition strategy, and real-time planning flight path was optimized by B spline, its simulation test was done by Matlab.Simulation result shows that the algorithm is feasible, the optimal flight path satisfies flight dynamic constraints and minimal flight radius, avoids unfeasible flight routine with sharp angles.More>

2006, 6(4): 84-87.

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Model and algorithm for airport gate assignment problem

CHEN Xin, LU Xun, ZHU Jin-fu

Abstract: To find feasible and effective solutions of gate assignment problem for medium-small airports, minimum passenger walking distance was taken as optimizing objective, an integer program (IP) model was developed, an improved heuristic algorithm was put forward to resolve the model, which can reduce search space and improve resolution efficiency.Computation result shows that the model and the algorithm are feasible, the algorithm has higher resolution efficiency and lower computational complexity (polynomial) compared with that (exponential) of CPLEX, the computation error of the algorithm is 5.2% compared with the computational result of CPLEX.More>

2006, 6(4): 88-90.

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Automatic classify method of traffic sign

CHU Xiu-min, YAN Xin-ping, MAO Zhe

Abstract: To achieve automatic classifying traffic sign, a sign classifying method was put forward, sign HSI color model was obtained from sign RGB model, the edge of traffic sign image was detected by Sobel operator, sign region was filled by line-scanning method to gain the binary image of traffic sign, the invariant-moments and form factors of traffic sign image were extracted as image feathers, the shape of traffic sign was recognized by BP nerve net classifier, a euclid-distance classifier was designed to recognize the background color of traffic sign by H and I values.Automatic classifying result shows that the shape and color of traffic sign can be recognised accurately by the method.More>

2006, 6(4): 91-95.

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Deploying model of city guide signs based on intersection functions

HUANG Min, YU Zhi, XIAO Guo-rong

Abstract: The modeling method of inter-town guide signs based on road network topology was discussed, the concepts of guide sign items were proposed, and the state functions of guide signs were given.Three intersection functions, such as adjacent node set, node-arc angle set and connected node set, were presented, and based on the shortest path method proposed by Dijkstra, a road guide sign model was built by using the intersection functions.The main idea of the model was as follows: destination city was taken as searching center, road guide signs were deployed by searching the adjacent node set of intersection in the influential region of the city, every path designated by road guide signs was an optimal one.Example analysed result shows that the road guide signs created by the model can effectually guide road users to aims.More>

2006, 6(4): 96-100.

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On-ramp fuzzy logic control and auxiliary project design of freeway

ZHANG Sheng-rui, TANG Guo-xi

Abstract: In order to ensure the safe, expedite and comfortable operation of freeway mainline, and to lessen its influence on linked roads, a fuzzy logic controller of on-ramp was constructed, three kinds of auxiliary on-ramp projects were designed.In practical engineering, the upstream density, downstream density and entrance queue of vehicle-flux were selected as controller inputs, the metering rate of on-ramp was selected as controller output.Calculated result indicates that downstream vehicle speeds in mainline are decreasing obviously with the increasing of vehicle number in on-ramp; according to upstream density, downstream density and vehicle number, ramp metering rate can be calculated; the entrance of on-ramp vehicles can be controlled by the real-time adjusting of the metering rate of freeway on-ramp, the application of auxiliary projects can alleviate the congestion of linked roads, and improve the safety and efficiency of freeway running.More>

2006, 6(4): 101-104.

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Bi-level programming model and algorithm of optimal toll rate for highway network

HUANG Ya-fei, LIU Tao

Abstract: In order to find system and science method to calculate the optimal toll rate of highway network, a bi-level programming model to determine the optimal toll rate was put forward, the relationship among highway network managers, toll road operators and users was described.Its upper objective function was consumer surplus which should be maximized, its lower-level problem was multi-vehicle-type stochastic user equilibrium model with elastic demand.A kind of hybrid optimization algorithm combined genetic algorithm and simulated annealing to solve it was proposed.Calculation result shows that the value of revenue for highway network influences the toll rate directly, furthermore, it influences OD traffic flows, and the influence on the vehicle types with low time value is more obvious than on the vehicle types with high time value, which indicates that the model can balance the benefits among managers, operators and users reasonably, and reflect the fact more accurately when considering vehicle types; compared with genetic algorithm and simulated annealing algorithm, the computation result of the algorithm for the model is least, the algorithm is feasible.More>

2006, 6(4): 105-111.

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Laws and models of traffic accidents

ZHOU Qian, LU Hua-pu, XU Wei

Abstract: The characteristics of social economies and traffic accidents in tens of countries were studied, the traffic safety development model proposed by foreign researchers was verified with recent accident data, the applicability of the model under different motorization levels was analyzed, the development characteristics of Chinese traffic accidents were studied, the traffic accident model adapting Chinese traffic safety and motorization pattern was put forward.Analysis result indicates that the levels of traffic accidents can be explained by preliminary motorization levels in different countries, but can not be deduced by mature motorization levels, Chinese level of traffic accidents is better than most of other countries at the same level of motorization.The development stage of Chinese traffic accidents is presented, in which the level rapilly worsens, and the traffic death toll continually increases.More>

2006, 6(4): 112-115.

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Characteristics of traffic safety on desert highway

SIMUTULA Ai-li, LI Xin, DONG Chun-guang

Abstract: In order to analyze the present situation, characteristics and main causes of traffic accidents on desert highway, the statistical data of traffic accidents were collected, and an interior field investigation was executed on Taklimakan desert highway.Study result shows that the numbers of traffic accidents are greater in spring and autumn than in winter, and the numbers are bigger at noon, in the evening and at night than the other daily time; the number of traffic accidents decreases from north to south along Taklimakan desert highway, but the ponderance of traffic accidents increases from north to south; main weather factors that affect traffic safety are high temperature and strong wind; driver is the main cause of traffic accidents; traffic environment often causes drivers breaking traffic rules; trees planted along desert highway also affect driving safety in a certain extent; there are still some shortages of essential safety guarantee facilities and reaction mechanism on desert highway.More>

2006, 6(4): 116-121.

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Critical slope length computation of engine brake inefficacy

XIAO Run-mou, YE Yan-xian, ZHOU Xiao-yue, LIU Dong

Abstract: To lower automobile traffic accident rate effectively on continuous downhill road and enhance its active safety of driving, the slope length of braking inefficacy was studied under engine braking, brake test on flat road in automobile proving ground was done, the elevated temperatures of brake drums under emergency braking case were measured, the elevated temperature model of main brake drums was established by least-squares procedure, the critical slope lengthes of automobile main brake inefficacy under engine braking on various longitudinal slopes in mountain area were deduced.Computation result indicates that when automobile runs at the safe-stable speed of 40 km·h^-1 on 5% ramp and driver adopts the No.Ⅲ gear engine braking, the critical slope lengthes of front-and-aft wheel main brake inefficacy respectively are 15263 m and 12368 m, which not only satisfies running distance request, but also meets running speed request, so it is a feasible and safe driving method on long downhill.More>

2006, 6(4): 122-126.

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2006 Vol. 6, No. 4

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