引入制动管路约束的车辆操纵稳定性控制方法研究

以DYC(Direct Yaw-moment Control)控制器为基础,结合制动管路摩擦力模型的约束条件,建立了全轮纵向力优化分配算法。利用Matlab软件对建立的车辆动力学模型和全轮纵向力分配算法进行了仿真分析,结果表明该算法能够进行有效的全轮纵向力分配。     

20000吨级自航半潜船冷却水系统故障诊断与排除

随着技术发展,越来越多的船舶采用电力推进装置.同常规推进相比,更多的设备比如变频器、变压器,需要采用淡水冷却,而且它们往往布置在机舱外,增加了中央冷却水系统调试的难度.介绍了采用电力推进的自航半潜船,中央冷却水系统调试中暴露出的问题,并针对其中的主要矛盾,提出了解决方案.     

Productivity and returns to scale of container ports

This is an empirical analysis of the performance of the five major container ports of the East Coast of the United States: Boston, New York-New Jersey, Philadelphia, Baltimore and Hampton Roads. The data through 1978 indicate wide disparities in the productivity of these facilities. They also suggest that container ports exhibit significant returns to scale throughout the range of observation, that is up to 15 Mt a Year. These findings indicate that a national policy of developing small ports is not economically attractive, and that specific investments should be made most carefully.     

Refined parameter and uncertainty estimation when both variables are subject to error. Case study: estimation of Si consumption and regeneration rates in a marine environment

The problem of estimating parameters and their uncertainty from experimental measurements in marine ecosystems is a common task and often necessitates solving nonlinear equations. If the measurements are subject to individually varying errors (i.e., heteroscedastic data), the parameters are often estimated using a Weighted Least Squares (WLS) method. For estimating the parameter uncertainties, a linearized expression for the covariance matrix exists. Yet, both methods assume that the errors on the independent variable, also called “input”, is negligible, which is often not true. For instance, in order to determine uptake and regeneration rates of silicic acid by phytoplankton, concentration and isotopic abundance measurements are performed at the beginning (input) and at the end (output) of an incubation experiment. Here, the so-called input and output are measurements of the same quantities, i.e., determined in exactly the same way, only differing by the time at which the measurements were performed. Clearly, there is no reason to assume that the input measurements are subject to less error than the output measurements. We propose a refinement of the two abovementioned estimation methods which enlarges their applicability to cases where input noise is not negligible. The refined methods are evaluated on the uptake and regeneration processes of silicic acid and compared to the original procedures using Monte-Carlo simulations. The results reveal a smaller bias for the refined WLS estimator compared with the original one. An additional advantage of using the refined WLS cost function is that its residual value can be interpreted as a sample from a χ² distribution. This property is especially useful because it enables an internal quality control of the results. In addition, the parameter uncertainty estimation is significantly improved. By neglecting the effect of the input noise, a (potentially) important origin of the parameter variation is simply ignored. Therefore, without the refinement, the parameter uncertainties are systematically underestimated. Using the refined method, this systematic error disappears and on the whole, the parameter standard deviations are accurately estimated.     

谈高等级公路造价管理应用微机的必要性

结合实例比较 ,说明在高等公路造价管理中应用微机的必要性及优点 ,认为应把微机应用贯穿于整个造价管理工作中。     

铁路工程地质勘察监理探讨

论述了铁路工程地质勘察监理的产生背景和发展历程，分析了建设、监理和勘察三方对铁路工程地质勘察监理的认识过程，阐明了铁路工程地质勘察监理中应注意的问题，提出了发展铁路工程地质勘察监理的建议。     

Optimal Design of Running Gears Part II. Applications

In the second part of the paper applications are shown for the two-axle unsymmetric running gear and for symmetric running gears with two, three and four wheelsets.     

连续配筋混凝土板在岩溶及采空区公路建设中的应用

采用连续配筋混凝土板对岩溶及采空区路基进行处理，可增强路面层抵抗弯矩的能力，消除安全隐患，具有良好的经济效益。本文给出的连续配筋混凝土路面板配筋计算公式经济合理，三维有限元整体分析安全可靠，对于西部高等级公路岩溶及采空区的处理具有较好的借鉴意义。     

悬索桥施工质量控制技术

结合宜昌长江公路大桥的建设实际，分析了大跨度悬索桥关键部位质量的影响因素，研究了相应控制质量的主要技术措施和方法。     

水泥强度快速检测试验研究

工程实际中应快速测定硅酸盐水泥强度，对于加快土木建筑工程施工速度，确保混凝土质量，充分合理地利用水泥活性十分重要，根据对承德地区14个品牌的175组新标准水泥的试验结果，研究了1.5h压蒸养护促硬快速检测水泥强度与28d标准强度之间的关系。通过分析它们之间的回归关系曲线表明，1.5h压蒸养护促硬快测水泥强度与28d标准强度之间的相关性高度显著。研究结果还表明，利用1.5h压蒸养护促硬快速检测和推测水泥强度的方法切实可行，该方法所建立的上述关系曲线适合于进行区域性推广应用。