基于最佳有限网格的应力修匀

本文建议了一种新的应力分析方案。新方案结合了自适应技术和应力修匀技术的长处，对于改进有限元应力解有明显的效果，且由于算法简便，计算效率比通常的自适应方案高，因此易于纳入已有的通用程序。     

某连续梁桥主桥合拢段施工与监控技术研究

以湖南省某预应力混凝土连续箱梁桥为依托工程,阐述了主桥合拢段合拢前和合拢过程中的施工方案,同时结合合拢段施工方案制定了施工监控方案,并将监控应力实测值和ANSYS数值模拟理论值进行对比分析。结果表明：主桥合拢段施工过程中箱梁应力在预应力张拉20 d内变化幅度较大,应力指标总体满足规范要求;合拢施工监控方案采取的应力测试方法合理可行,应力测量仪器能够准确的反映现实情况。最后,总结了合拢段施工中的技术要点与施工注意事项,可供借鉴。     

基于无线传感网络技术的门式起重机无线应力监测系统设计

通过对起重机结构与应力分析,确定了影响作业安全的主要应力监测点;提出了基于无线传感网络技术的应力监测系统总体设计原则和方案;选用了Crossbow公司的IRIS系统作为无线传感网络平台,设计了应变监测节点相关电路与节点程序,开发了用于门式起重机应力监测的LABVIEW软件。该系统可实现对起重机结构的应力实时监测、超限自...     

浅谈橡胶沥青应力吸收层在桥面铺装中的应用

随着城市话进程的不断加快,城市的交通状况变得越来越拥堵,为缓解城市中重点道路的拥挤情况,桥梁的建设成为首选方案。作者根据多年的桥梁建设施工经验,讲述了橡胶沥青应力吸收层在桥梁建设过程中的使用情况,重点分析了其原理以及施工技术。橡胶沥青应力吸收层具有以下特点:吸收应力、减少反射裂缝、防水、粘接力强等。     

桥梁桁架焊接典型热点局部应力集中的实验检测分析

阐述了具有焊接热点的桥梁桁架缩尺模型的建立,对桥梁桁架焊接热点实验测点布置、约束及加载方案进行说明;介绍了桥梁桁架缩尺模型热点应力检测分析。对桥梁桁架结构典型焊接节点区域,开展应力状态有限元测试分析,获得测区的典型局部结构应力参数值及分布状态,对桥梁桁架结构的抗疲劳提供技术研究参考。     

高速铁路CFG桩复合地基处理方案数值模拟

采用有限元分析软件对CFG桩复合地基特性进行了研究,分析了不同的复合地基处理方案,如水泥土、桩帽网、和桩板方案对沉降规律和桩土应力比的影响．研究表明：复合地基处理方案为水泥土方案时路基沉降量最大、桩土应力比最小,地基面有明显沉降盆;桩板方案时路基沉降量最小、桩土应力比最大、地基面沉降更加均匀．     

基于有限元桥梁伸缩缝清理器械的优化设计

针对当前工作中使用的桥梁伸缩缝清理器械的缺陷,采用面向制造的先进技术,运用UG、ANSYS软件对桥梁伸缩缝钩刀进行了CAD/CAE建模和力学特性研究,得到了钩刀单元的应力分布,从改善力学特性的角度提出了钩刀的优化设计方案,优化后分析结果肯定了优化方案的可行性。     

全暗挖十字换乘地铁车站交叉节点施工方案比选——以长春地铁1号线解放大路站为例

在全暗挖十字换乘地铁车站交叉节点施工方案设计上,有多种方案可以选择。以长春地铁1号线解放大路站交叉节点施工方案比选为例,从沉降量大小、关键节点应力分布和土体塑性区变化等方面进行详细分析,得出了从衬砌端破马头门施工连接段的最优方案。可以为今后换乘车站及其关键节点施工技术提供技术和经验的参考。     

有限元分析中的应力后处理问题

本文在回顾现有应力修匀方案的基础上,提出了一种新的、更为合理的方法。文中还就基于应 力修匀的平衡迭代技术进行了探讨,指出了这种方法的缺陷,并提出了改进的途径。      

大跨度双连拱隧道施工方案对比优化分析

针对隧道的特点,模拟了三种不同施工方案的隧道开挖过程,得到了不同方案下的围岩应力、中隔墙应力、拱腰、拱顶及地表沉降,并从安全储备、施工难易程度、施工工期及工程投资等方面进行了三方案的对比分析,从而优化本隧道的施工方案,并为同类工程提供参考。     

Finite-Time Attitude Tracking Control of Spacecraft with Actuator Saturation

The attitude tracking control problem of a rigid spacecraft with actuator saturation is investigated in this paper. A finite-time attitude tracking control scheme is presented by incorporating sliding mode control (SMC) and adaptive technique. Specifically, a novel time-varying sliding mode manifold is first developed that aims at regulating the attitude tracking error to equilibrium point within a certain finite time. Moreover, it can be specified a priori by the designer according to the mission requirement. Subsequently, an adaptive controller is derived by using the SMC in conjunction with adaptive technique. The designed controller is capable of ensuring that the state trajectories reach to sliding regime within a finite time, and hence that attitude tracking error can converge to zero in a finite time with the aid of the developed sliding dynamics, despite the presence of exogenous disturbances, unknown inertia properties and saturation nonlinearities. Finally, the simulation experiments are carried out to demonstrate the effectiveness of the proposed control scheme.     

DESIGN ISSUES FOR BIT RATE-ADAPTIVE 3R O/E/O TRANSPONDER IN INTELLIGENT OPTICAL NETWORKS

IntroductionWith the rapid progress of Optical Add- DropMultiplexer and Optical Cross- Connect( OADM/OXC) technologies,itis becoming possible for car-riers to provide high- speed services such as OC- 48/OC- 1 92 and Gigabit Ethernet transmission chan-nels directly from the optical domain. Line speedsof electrical layer devices such as IP routers andATM switches are continually growing to satisfythe increasing demands of data,as evidenced bythe introduction of line card speeds of OC- …     

隧道超欠挖的力学效果分析

用理论解析和自适应有限元法研究了超欠挖对隧道稳定性的影响，结果表明：隧道超欠挖的存在及其沿设计轮廓的不均匀分布造成的开挖轮廓的凹凸不平，将引发隧道周围岩体中的局部应力集中，提出了控制这种局部应用力集中对隧道稳定性影响的基本措施。     

Simple adaptive filtering scheme to improve measurement accuracy of gyroscope on angular motion base

The objective of this work is to improve the measurement accuracy of a gyroscope on a angular motion base with a simple adaptive filter scheme. Two main topics are highlighted in this work. The first topic is to show building a dual-process model employed for the conventional Kalman filter. The second topic is to show developing a modified noise adaptive algorithm when measurement noise and process noise are unknown. The experimental results are presented to show that the simple adaptive filtering scheme outperforms the other conventional scheme in this paper in terms of noise reduction.     

非线性系统的智能容错控制

本文提出一种针对非线性系统问题的智能容错控制方案,该方案基于自适应模糊逻辑系统的学习方法,论述了控制器作为一个扩充的体系,集成了自适应模糊控制器、检测控制器及调节控制器三者的功能。仿真表明,所提出的控制方案能够有效的鉴别和适应非线性未知错误,且被控系统在不确定及产生错误时具有很好的稳定性和鲁棒性。     

牵引网馈线自适应保护原理及配置方案研究

首先讨论了影响牵引网馈线保护原理及配置的因素,然后分析了牵引网馈线自适应保护的原理,其中重点探讨对距离保护传统阻抗多边形进行改进的可行性,并利用现场运行数据进行了仿真验证,最后提出了牵引网馈线自适应保护的配置方案．     

军用梁＋支架法悬臂浇筑在铁路客运专线桥梁施工中的应用

根据铁路客运专线连续梁（32＋48＋32）m施工箱梁自重大、工期紧等特点,提出军用梁＋支架法悬臂浇筑施工方案,介绍了采用的施工设备和具体实施方案。与常用的挂篮悬臂浇筑方案对比,此方法具有用钢量少、通用程度高、技术难度小、节约工期等优点,可为其他相应的桥梁施工提供参考。     

Distributed certificateless key encapsulation mechanism secure against the adaptive adversary

This paper proposes an adaptively secure solution to certificateless distributed key encapsulation mechanism from pairings by using Canetti's adaptive secure key generation scheme based on discrete logarithm. The proposed scheme can withstand adaptive attackers that can choose players for corruption at any time during the run of the protocol, and this kind of attack is powerful and realistic. In contrast, all previously presented threshold certificateless public key cryptosystems are proven secure against the more idealized static adversaries only. They choose and fix the subset of target players before running the protocol. We also prove security of this scheme in the random oracle model.     

A Practical Adaptive TuCM Scheme for Rayleigh Flat Fading Channels

IntroductionAs stated in Ref.[1 ],if the channel state isknown atthe transmitter,then channel capacity isachieved by adapting the transmit power,data rateand coding scheme relative to this fade state.Based on those results,an uncoded adaptive modu-lation was proposed[2 ] .This adaptive modulation is1 7d B more power efficientthan non- adaptive mod-ulation in fading.Combining trellis coded modula-tion ( TCM) with adaptive modulation,an adaptivecoded modulation was studied[3 ] .The results sh…