城市交通规划中的环境影响评价体系分析

随着时代的发展,对城市交通规划的战略环境影响评价已经从研究阶段走向了应用阶段。分析了制订城市交通规划战略环境评价的原理,探讨了城市交通规划指标框架和指标体系集的建立,提出了交通规划战略环境评价程序的流程。     

On a Fast P-ary m-Sequence Transform

m-sequences have been used widely in many applications,but the corresponding computation of the correlation-detection is overwhelming N^2 operations,where N is the length of the m-sequence,such that it is unpractical. In this paper,a transform from p-ary m-sequence matrices to generalized Hadamard Matrices is developed;and then by the fast generalized Hadamard matrices transform,a fast p-ary m-sequence transform is developed.The results show that the computation can be dramatically reduced from N^2 to NlogpN operations,so the fast p-ary m-sequence transform could enable a rapid correlation-detection at the receiver.     

确定节理岩体抗剪强度的结构影响函数法

本文通过室内直剪试验和三轴压缩试验研究了常见节理岩体类型的抗剪强度特征后,提出用抗剪强度“结构影响函数”来描述岩体结构对节理岩体抗剪强度的综合影响和用结构影响函数法来确定节理岩体的抗剪强度。该方法较现场试验法要简便、迅速、经济。     

Static and Dynamic Stability of a Class of Three-Axle Railway Vehicles Possessing Perfect Steering

For railway vehicles having coned wheels mounted on solid axles there is, in general, a conflict between stability of lateral deviations from the motion along the track and ability to steer round curves. However, the three-axle vehicle with zero bending stiffness and with shear elasticity between all wheelsets can satisfy the requirement of perfect steering and for a range of values of equivalent conicity possesses both static and dynamic stability. The static and dynamic stability of the most general form of symmetric three-axle vehicle is investigated, and stability criteria derived.     

Numerical Simulation of Carbon Concentration Profiles in Case Layer of Steel 20 RE-Carburized in Multipurpose Furnace with Drip-Feed Atmosphere

IntroductionTheworkonthermochemica1treatInntswithasadditiOnswasshmulatOdbybasicresearchinl982inChinall].SignilicantProgfesshasbeenmadedurillthepastdecadeinthefield.TheresultsshowthatontheonehandtheREe1emedscanacceleratethedecomPositionofthemediumandactiVatethecarburizedschceofsteelsandthusenhancethecoefficientofcarbontransfer(D").OntheotherhandatelevatedtemPeratUreREelements,althoughtheyhavemuchbiggeratOmicsizesthaniron,couddiffuseintobasedalloystOasignilicamdepth.MoreifllPortantiXtheP…     

A SIMULATIONAL STUDY OF PRECIPITATION KINETICS AND MORPHOLOGY IN NITRIDATION OF ALLOY STEELS

IntroductionPreopationofultrideslikeAIN,Cffe,VN,TNandNbNplmpakeyroleinschceStrengtforngofalloysteelsbynitrdation.TheprocessisbasicallyillternaldridationofallOyscOmPosedofbasematalslikeFeandreactiveelemedslikeAl,UndecolltrOlledenvirondtoprevIttfonnndonofsdsescaleofbasemetalnitrdes,resemblinginternaloxidationofsimilartweofalloys[l].NUmericalmassttansferanalysisofnitridationkineticshasbeenwellestablished['],howeycfthefactthatthcyneglectinforactionofninogeneddride-formingatomsPreventsitfro…     

Advanced Ground Vehicle Suspension Systems - A Classified Bibliography

This bibliographical list classifies the extensive literature related to the dynamic analysis and control design aspects of advanced ground vehicle suspension systems. It is restricted to the design of advanced suspensions for ride quality and safety. Brief generalized notices and definitions are presented.     

Urban Space Distribution and Sustainable Transport

In many cities of the world, road space is increasingly contested. Growing vehicle numbers, traffic calming and the development of new infrastructure for more sustainable transport modes such as bicycles have all contributed to pressure on available space and conflicts over the allocation of space. This paper provides the first assessment of urban transport infrastructure space distribution, distinguishing motorized individual transport, public transport, cycling and walking. To calculate area allocation, an assessment methodology was developed using high-resolution digital satellite images in combination with a geographical information system to derive area measurements. This methodology was applied to four distinctly different city quarters in Freiburg, Germany. Results indicate that space is unevenly distributed, with motorized individual transport being the favoured transport mode. Findings also show that if trip number to space allocation ratios are calculated, one of the most sustainable transport modes, the bicycle, is the most disadvantaged. This suggests that area allocation deserves greater attention in the planning and implementation of more sustainable urban transport designs.     

城市交叉口渠化设计方法与评价——以成都市为例

在指出渠化概念及设计原则的基础上,分析了成都市交叉口的特色,同时结合了交叉口常用的渠化设计方法,以具体案例分析了具有成都特色的交叉口渠化设计方法,最后对这些渠化设计方法进行了评价。     

Parallel Distributed Implementation of Truss Optimization on a Local Area Network

A two-level optimization method for the design of complex truss and parallel distributed implementation on a LAN is presented using parallel virtual machine (PVM) for Win 32 as message passing between PCs. The volumes of truss are minimized by decomposing the original optimization problem into a number of bar optimization problems executed concurrently and a coordinate optimization problem, subject to constraints on nodal displacements, and stresses, buckling and crippling of bars, etc. The system sensitivity analysis that derives the partial derivatives of displacements and stresses with respect to areas are also performed in parallel so as to shorten the analysis time. The convergence and the speedup performances as well as parallel computing efficiency of the method are investigated by the optimization examples of a 52-bar planar truss and a 3 126-bar three-diraensional truss. The results show that the ideal speedup is obtained in the cases of 2 PCs for the 3 126-bar space truss optimization, while no speedup is observed for the 52-bar truss. It is concluded that (1) the parallel distributed algorithm proposed is efficient on the PC-based LAN for the coarsegrained large optimization problem; (2) to get a high speedup, the problem granularity should match with the network granularity;and (3) the larger the problem size is, the higher the parallel efficiency is.