复杂悬跨条件下的管线涡激振动分析(英文)

Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections, but also generates vortex induced vibration (VIV), which can lead to fatigue issues. The phenomenon, if not predicted and controlled properly, will negatively affect pipeline integrity, leading to expensive remediation and intervention work. Span analysis can be complicated by: long span lengths, a large number of spans caused by a rough seabed, and multi-span interactions. In addition, the complexity can be more onerous and challenging when soil uncertainty, concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a .state-of-the-art. finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.     

船用微型锅炉非线性温度系统控制器仿真与研究

为了实现对船用微型锅炉高、低水温的控制，在Matlab环境下对实测和计算的数据进行曲线拟合，建立了船用微型锅炉水温系统的非线性数学模型。运用滑模变结构控制理论，选取线性切换面和比例型趋近率，设计了一种滑模控制器，实现了双输入双输出非线性耦合温度系统的解耦和控制。通过Matlab／Simulink软件的仿真，结果显示滑模变结构控制算法对非线性系统的控制有响应快、超调小、调节时间短、无误差和抖动的特点。     

财务报告目标与收益报告模式的关系

收益报告是现代财务会计的核心环节，其内容和模式取决于财务报告目标，就财务报告目标的两种主要观点（受托责任观和决策有用观）及与其对应的两种收益报告模式（传统收益模式和全面收益模式）的关系进行了探讨，并认为我国可以凭借会计准则发布的契机，有目标、有步骤地进行深化收益报告模式的改革。     

SW-220K型转向架参数优化试验研究

对配装SW—220K型转向架的25T型客车进行了振动试验;分析了车辆的主要振型;分别进行了采用不同空气弹簧、二系阻尼系数值时的试验,根据垂向、横向平稳性指标测试结果,得出了采用原型空气弹簧结构并增大二系垂向阻尼系数值能够改善车辆运行性能的结论。     

企业发展极构建及其知识联组实现方式

科技型企业面临着发展高风险与经济增长重任的尖锐矛盾，这一矛盾的有效化解须从科技型企业自身角度在发展路径方面作出创新性的调整－通过构建企业发展极，形成核心竞争力，而达成这个目标的最迅捷有效的企业组织变革措施是采取相宜的知识联组方式。     

A modified integral sliding mode control to lateral stabilisation of 4-wheel independent drive electric vehicles

This paper presents a novel sliding mode controller (SMC) and its application in the lateral stability control of a 4-wheel independent drive electric vehicle. The structure of the SMC is modified and online-tuned to ensure vehicle system stability, and to track the desired vehicle motion references when an in-wheel motor fault happens. The proposed controller is faster, more accurate, more robust, and with smaller chattering than common SMCs chatter. The effectiveness of the introduced approach is investigated through conducted simulations in the CARSIM and MATLAB software environments.     

建筑企业工程施工合同管理的研究

施工合同管理是理顺生产经营秩序，控制与降低成本，提高建设项目经济效益的关键。此文列举了目前工程施工合同在合同文本内容、合约条款履行、索赔管理和人员管理等方面存在的问题，分析问题存在的原因，认为规范施工合同文本、健全合同管理机构、营造“伙伴关系”的合同管理氛围、创新和完善合同管理模式是今后合同管理的主要努力方向。     

Sliding mode observers for vehicle mode detection

This paper explores the use of sliding mode observers to detect the onset of potentially dangerous vehicle modes such as oversteer, understeer or split-μ braking. Provided these modes can be detected quickly enough, existing stability controllers can be engaged to ensure safe performance of the vehicle. It is shown that the equivalent output error injection signals associated with the sliding mode observer have distinctive signatures depending on the particular mode encountered. Appropriate thresholds on these signals can be set so the scheme ignores variations which arise during normal driving, but can detect and isolate different undesirable vehicle modes within 0.3 seconds of their onset.     

A study on the effect of different tyre imperfections on steering wheel vibration

Multibody dynamics and tyre models have made possible detailed analysis not only for ride and handling, but also for determining their effects on tyre nonuniformities. The aim of this paper is to analyse the steering wheel vibration, both shimmy and shake, excited by different tyre imperfections by using the commercial simulation package ADAMS/car 2005R2 and FTire. Different settings with respect to imperfection locations, amount, and the combined effects of defects have been studied. An interesting beat phenomenon is observed when all the wheels have imperfections. A procedure to determine the type of imperfections in the tyre from the results of the test rig has also been proposed.     

降雨作用下裂隙红黏土边坡渗流特征与冲刷模式

针对降雨作用下裂隙红黏土边坡失稳破坏问题，开展红黏土边坡裂隙演化、降雨入渗及冲刷模型试验，提出基于图像摄影识别技术的边坡裂隙特征及含水率分布定量表征方法，揭示红黏土边坡裂隙演化规律，分析裂隙发育程度与降雨强度对红黏土边坡渗流特征与冲刷模式的影响。结果表明：干燥作用下红黏土边坡表面裂隙发育，其中坡面裂隙发育最强烈，其最大裂隙平均宽度为4.1 mm，最大裂隙深度为7.7 cm，最大裂隙率为10.4%，但坡底子裂隙和分支裂隙发育最充分，且主裂隙最先出现于远离坡面处；降雨作用下，雨水极易沿坡表裂隙形成优势流迅速渗入边坡内部，使边坡含水率增加且呈不均匀分布，出现局部暂态饱和区；裂隙发育程度和降雨强度的增强均会提高前期降雨入渗速率，并增加最终降雨入渗深度，其中坡底处入渗深度最大；极端降雨对裂隙红黏土边坡冲刷作用明显，造成坡面松散层流失，坡底显现冲刷痕迹，坡脚局部发生滑动。基于图像摄影识别技术定量分析边坡含水率分布的方法简单有效，研究成果可为裂隙性红黏土边坡灾害防治提供参考。