基于压力变送器的桥梁挠度监测系统研究

挠度反映了桥梁结构的整体刚度，是评价桥梁安全性的重要依据。参考国内外桥梁挠度监控系统的最新发展状况，对钢桁架拱桥的挠度监测系统加以研究，提出挠度监测系统的方案一为桥梁挠度的实时监控及桥梁结构状态的健康监测提供第一手依据。     

双横臂独立悬架转向梯形断开点位置的优化及分析

本文应用空间机构运动学原理对双横臂独立悬架进行空间的运动计算。     

发动机零部件结构知识库管理系统的研究与开发

为了降低汽车发动机新产品关键技术的研发成本,提高自主开发的设计水平,创建了产品设计知识库系统.利用知识工程和互联网技术,以目标样机关键零部件结构知识和数据管理为研究对象,对发动机零部件结构知识进行了系统划分,开展了知识库数据管理系统的研究,建立了基于Benchmarking数据采集的发动机关键零部件知识库数据管理系统,实现了对发动机设计知识的查询和录入功能.     

Effect of operating parameters on diesel/propane dual fuel premixed compression ignition in a diesel engine

In this research, the effects of three operating parameters (Diesel injection timing, propane ratio, and exhaust gas recirculation (EGR) rates) in a diesel-propane dual fuel combustion were investigated. The characteristics of dual-fuel combustion were analyzed by engine parameters, such as emission levels (Nitrogen oxides (NO_x) and particulate matter (PM)), gross indicated thermal efficiency (GIE) and gross IMEP Coefficient of Variance (CoV). Based on the results, improving operating strategies of the four main operating points were conducted for dual-fuel PCCI combustion with restrictions on the emissions and the maximum pressure rise rate. The NOx emission was restricted to below 0.21 g/kWh in terms of the indicated specific NO_x (ISNO_x), PM was restricted to under 0.2 FSN, and the maximum pressure rise rate (MPRR) was restricted to 10 bar/deg. Dual-fuel PCI combustion can be available with low NO_x, PM emission and the maximum pressure rise rate in relatively low load condition. However, exceeding of PM and MPRR regulation was occurred in high load condition, therefore, design of optimal piston shape for early diesel injection and modification of hardware optimizing for dual-fuel combustion should be taken into consideration.     

一类新自治混沌系统的非线性反馈控制

通过数值方法,研究了一类新的自治混沌系统的非线性反馈控制问题.利用系统的Lyapunov指数和分数维以及在不同相平面上的Poincaré截面图等混沌判据对系统的高分数维混沌特性进行了分析.基于非线性延迟反馈控制法则,选取了相应的合理控制参数,对这一类含有多个非线性项的三维自治混沌系统进行了有效的控制.结合相图,说明了这种方法对高分数维混沌系统的有效性和适用性.     

煤炭码头自动化运输系统容错控制方法

为了解决煤炭码头自动化运输系统对控制的可靠性和安全性要求,提出了一种容错控制方法。运用径向基函数神经网络构造故障诊断器,通过容错故障范例检索,建立了从故障诊断到控制律重构之间的映射关系,实施运输系统的控制律实时重构。应用结果表明:所提出的容错控制方法明显提高了煤炭码头自动化运输系统的技术性能和安全可靠性,系统的各类故障的识别率大于97%,各类故障的误诊率小于1%,系统的有效度由原来的90%提高到98%以上。     

缺血后处理对大鼠肠缺血-再灌注损伤肠黏膜细胞线粒体的影响

目的探讨缺血后处理对大鼠肠缺血-再灌注损伤肠黏膜细胞线粒体的影响。方法SD大鼠32只随机分为4组(n=8):假手术(S)组、缺血-再灌注(I/R)组、缺血预处理(IPC)组、缺血后处理(I-post)组。应用透射电子显微镜、四甲基偶氮唑蓝(MTT)比色法、激光共聚焦扫描显微镜分别观测各组大鼠肠黏膜细胞线粒体的形态结构、呼吸功能以及线粒体跨膜电位的变化。结果与I/R组相比,I-post组和IPC组大鼠肠黏膜细胞线粒体形态结构改变明显减轻,线粒体呼吸功能和线粒体跨膜电位明显升高(P<0.05);I-post组与IPC组相比,差异无统计学意义(P>0.05)。结论缺血后处理抗大鼠肠缺血-再灌注损伤的作用机制可能与改善肠黏膜细胞线粒体的形态结构和呼吸功能及提高线粒体跨膜电位有关。     

交通影响分析中路网可靠性研究

将路网可靠性的宏观理论微观化,应用到建设项目交通影响分析中,并根据交通影响分析的特性给出了适用性较强的计算方法.结合某商业场所交通影响分析的具体实例,验证了可靠性理论评价分析交通通行状况的合理性,并分析了路网可靠度与饱和度的关系.     

Effect of radial interference on torque capacity of press- and shrink-fit gears

Some gears in an automobile transmission have to be mounted by being press-fitted on a shaft instead of splines. The torque capacity of the press-fitted gear will be proportional to the radial interference. The excessive interference, however, will increase the gear radial deformation. In this paper, the press- and shrink-fit and the subsequent torque capacity test were investigated by finite element analysis, theoretically and experimentally. The static and dynamic coefficient of friction were determined.