悬索桥的非线性自由振动方程

本文给出了悬索桥横向—竖向—扭转耦合非线性自由振动的一般微—积分方程,通过引入无量纲量,得到了无量纲化方程,通过用线性问题主模态来表示解的表达式,得到N—耦合的二阶非线性常微—积分方程的三个方程组。     

基于B—P神经网络的混凝土软化模型

本文探讨应用神经网络技术模拟材料本构行为的若干问题，并用Ｂ－Ｐ神经网络建立开裂混凝土的软化模型。     

STUDIES ON BLOOD GLUTATHIONE PEROXIDASE PROTEIN LEVEL OF CHILDREN IN KESHAN DISEASE AND KASHIN-BECK DISEASE AREAS

Ｋｅｓｈａｎｄｉｓｅａｓｅ (ＫＤ) ,ａｎｅｎｄｅｍｉｃｃａｒｄｉｏｍｙｏ ｐａｔｈｙ ,ａｎｄＫａｓｈｉｎ Ｂｅｃｋｄｉｓｅａｓｅ (ＫＢＤ) ,ａｎｅｎｄｅｍｉｃｄｅｆｏｒｍａｔｉｖｅｏｓｔｅｏａｒｔｈｒｏｐａｔｈｙ ,ａｒｅｔｗｏｉｎｄｅｐｅｎｄｅｎｔｄｉｓｅａｓｅｓｗｉｔｈｕｎｋｎｏｗｎｃａｕｓｅ .ＰｒｅｖｉｏｕｓｓｔｕｄｉｅｓｈａｖｅｉｎｄｉｃａｔｅｄｔｈａｔｔｈｅｂｌｏｏｄＳｅｃｏｎｔｅｎｔａｎｄＧＳＨ Ｐｘａｃ ｔｉｖｉｔｙｏｆｒｅｓｉｄｅｎｔｓｉｎｔｈｅｅｎｄｅｍｉｃａｒｅａｓｏｆｂｏｔｈｄｉｓ…     

高导铝稳定化超导Monolithic导体耦合损耗

文中结出了多量高导铝稳定化超导monolithic导体耦合损耗的计算式。它表明使用大量稳定材的导体,在稳定材中的集肤效应将对耦合损耗有重要影响,尤其在高频段。实际上,起源于集肤效应的沿导体轴向电流损耗支配着整个的耦合损耗。这一特征与一般多芯线ac损耗理论不同,本理论计算结果与实验结果取得较好一致。     

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…