磁道钉导航的横向偏差等值线及其应用研究

阐述了基于磁道钉导航的车辆定位原理;利用磁道钉磁感应强度公式计算磁道钉周围磁场,生成以磁感应强度X和Z方向分量为横、纵轴的横向偏差等值线方程;基于此等值线方程,得到磁感应强度X,Z方向分量数据对所对应的横向偏差的计算方法,并给出实例验证.     

斜腿刚构桥转体施工控制技术研究

石太客运专线孤山大桥为两座单线桥,采用主跨90m的预应力混凝土斜腿刚构。由于桥位岸陡谷深,考虑施工辅助工程措施的可靠性,设计、施工大胆采用无支架施工新工艺,斜腿先进行竖向施工,而后转体,通过背索平衡采用悬臂法浇注梁体,目前此种施工方法国内尚无先例,因此在斜腿转体过程中的监控显得尤为重要,通过分析转体过程中斜腿及各转体设备的受力状态及转体到位后的斜腿线形控制,介绍了孤山大桥斜腿转体过程中的施工控制技术,并在大桥施工中得到了成功的运用,开创了斜腿刚构桥的一种新型施工方法,为同类型大跨斜腿刚构桥的施工控制提供了宝贵的经验。     

Serum concentrations of laminin and fibronectin in patients with acute coronary syndromes

Objective To study the serum iaminin (LN) and fibronectin (FN) changes in acute coronary syndromes (ACS), and explore the role of them in assessing the severity of ACS. Methods This study included 46 ACS patients [25 with acute myocardial infarction (AMI) and 21 with unstable angina (UA)], 51 stable angina (SA) patients and 47 people without CHD as controls. Serum levels of LN, FN, fibrinogen and blood fat were assessed. Coronary angiography were performed on 49 of them. Results The serum concentration of LN was lower in ACS patients [(85.20±27. 57)ng/mL], higher in SA patients [(116. 80 ± 28. 80)ng/mL] as compared to that in the control group [(100.06±29.96)ng/mL], with significant difference among the groups (P<0.05). No difference was found in FN among the three groups. However, the subgroup analysis in the group with ACS showed that the serum concentration of FN was significantly higher in UA patients [(229.60±121.39)μg/mL ], and lower in AMI patients [(108.31±47.12) μg/mL ]. The serum LN and FN concentration could respectively enter the logistic regression equations of ACS patients and US patients. Neither LN nor FN concentration was correlated with narrowing of coronary artery of angiography. Conclusion Serum LN and FN level may be a useful indicator for stability of atherosclerosis plaque in coronary arterial disease patients, but could not predict the extent of narrowing in coronary angiography.     

胃癌肝转移的危险因素分析

目的探讨胃癌肝转移与多种危险因素之间的关系。方法收集376例胃癌病例资料,选取12项指标作为胃癌肝转移的危险因素,采用Logistic回归方法,进行单因素和多因素分析。结果单因素和多因素分析结果显示胃癌的组织学类型、淋巴结转移和临床病理分期与肝转移有关。单因素分析还显示浸润深度也是与之有关的因素,而其他因素与肝转移无关。结论胃癌发生肝转移与肿瘤的组织学类型、浸润深度、淋巴结转移和临床病理分期有关。     

基于图像传感器的液位测量方法研究

文章利用激光笔与摄像头构建了一种非接触式液位测量装置。依据液面上的入射光斑中心与液面高度之间的函数关系，利用最小二乘法标定液位测量装置的参数，完成液位测量。由于液面的晃动具有周期性，文章通过自相关算法来判断晃动液面的振荡周期，对液面高度构成的振荡曲线进行最小方差拟合，一个周期内拟合函数上下积分值相等的点为液面高度。此算法实现了准确的实时地连续监测液位，可应用在工业液位测量等场合。     

海洋平台发电机保护研究

本文首先介绍了海洋平台电力系统发电机故障及异常运行方式的各类保护,随后就电压异常保护、过载保护和电流速断保护在整定设置过程中需要考虑的因素和注意问题展开讨论,最后以发电机综合保护继电器SR-489为例,讨论发电机综合保护装置应用过程中需要关注的关键事项.     

计算机网络常见故障的种类及检查方法

为迅速、准确地查找故障,将网络故障分为物理故障和逻辑故障,并对各类故障的检查方法和故障处理进行介绍.     

Identifying contributions of on-road motor vehicles to urban air pollution using travel demand model data

Ambient concentrations of pollutants are correlated with emissions, but the contribution to ambient air quality of on-road mobile sources is not necessarily equal to their contribution to regional emissions. This is true for several reasons such as the distribution of other pollution sources and regional topology, as well as meteorology. In this paper, using a dataset from a travel demand model for the Sacramento metropolitan area for 2005, regional vehicle emissions are disaggregated into hourly, gridded emission inventories, and transportation-related concentrations are estimated using an atmospheric dispersion model. Contributions of on-road motor vehicles to urban air pollution are then identified at a regional scale. The contributions to ambient concentrations are slightly higher than emission fractions that transportation accounts for in the region, reflecting that relative to other major pollution sources, mobile sources tend to have a close proximity to air quality monitors in urban areas. The contribution results indicate that the impact of mobile sources on PM₁₀ is not negligible, and mobile sources have a significant influence on both NO_x and VOC pollution that subsequently results in secondary particulate matter and ozone formation.     

山区高速铁路桥梁设计几个问题探讨

未来10年,我国将大量修建山区高速铁路。山区高速铁路桥梁应选择最小桥高的线路方案,慎重研究不良地质地段及上跨既有水利、道路、管线等设施桥址选择。简支组合箱梁、组合T梁采用较少,随着运架一体机的应用,保证了桥隧相连地段尽可能多地采用预制整孔箱梁。预应力混凝土连续梁是山区高速铁路首选特殊桥梁结构形式。圆端形墩和矩形墩各有优势,主要是外部条件决定墩形,地震区一般采用圆端形墩。建议墩高30 m以下采用流线形圆端形墩。矮墩应比较采用明挖扩大基础,钻孔灌注桩基础应根据不同覆土厚度、不同桩径、不同基岩实际情况、不同成孔方法等实际情况确定按柱桩或摩擦桩计算。     

基于UKF和线性优化的改进粒子滤波算法

针对标准粒子滤波算法存在的粒子退化问题,提出了一种改进的粒子滤波算法,该算法将不敏卡尔曼滤波算法（UKF）、线性优化的思想和基本粒子滤波算法相结合,运用不敏卡尔曼滤波算法获得重要性概率密度函数,提高了粒子的使用效率;运用线性优化的思想,保证了所有粒子都以一定的概率对状态估计作出贡献,提高了粒子的多样性。仿真结果表明,改进的算法很好的解决了基本粒子滤波存在的粒子退化问题,具有更高的状态估计精度。