铁路货车防盗系统设计

针对铁路运输的货物在途中被盗现象，提出了货车、集装箱防盗系统的设计原理，给出了系统硬件结构示意图和软件设计框图并对其在 Ｔ Ｍ Ｉ Ｓ中的使用前景进行了展望。     

NGTD12DD——德累斯登第二代城市轻轨列车

0引言 自从德国统一以来德累斯登交通运输公司(DVB)一直在实施更新改造.在机车车辆更新方面,采用了低地板技术.该公司首先在所属的维修厂成功地对部分老式Tatra有轨电车进行了现代化改造.     

Choice valuation of traffic restrictions: Noise, pollution, and congestion preferences. A note

This Note looks at the choice valuation restrictions on traffic entering the city of Lisbon, based on individual preferences in relation to noise, pollution and congestion. The analysis employs a questionnaire distributed in 2007 to ascertain the significant characteristics of traveling to Lisbon, with the aim of curbing the number of cars that are associated with the probability of individuals supporting a charge on motor vehicles entering the city. The model also takes into account the uncontrolled heterogeneity of the data.     

基于Biba模型的三权分立分析

强制访问控制是建设高级别安全信息系统的必要条件.本文基于Biba模型,重点给出了信息系统中系统管理员、安全管理员和安全审计员三权分立的形式化分析.通过分析,给出三权分立管理机制下,保障信息系统安全管理的条件.本文的结果在某国家级信息系统的具体建设中得到了应用.     

锰粉加工工人心血管功能的调查研究

对 ５５ 名锰粉加工工人和 ５６ 名对照工人的调查结果显示，工人工作地点 Ｍｎ Ｏ２ 浓度几何均值为 １９６ ｍ ｇ／ｍ ３ （锰尘 ０１７～２２．２４ ｍ ｇ／ｍ ３ ），样品超标率 ８８７％ 。接触组头晕头痛、睡眠障碍、容易疲劳和记忆不良的主诉率明显高于对照组（ Ｐ＜００５～００１）。接触组和对照组的心电图异常、高血压和低舒张压检出率未见显著性差异，其心率、 Ｐ Ｒ间期、 Ｑ Ｒ Ｓ波、收缩压和舒张压的均值比较也没有显著性差异。接触组心电图异常和低舒张压的 Ｏ Ｒ分别是 １．５６（９５％ 可信区间为 ０７０～３．５０）和 ２．０８（９５％ 可信区间为 ０１８～２３．５７）。     

Synoptic transects on the distribution of trace elements (Hg,Pb, Cd,Cu, Ni,Zn, Co,Mn, Fe,and Al) in surface waters of the Northern- and Southern East Atlantic

Surface seawater samples were taken in the framework of the GEOTRACES program on “POLARSTERN” expedition ANT XXIII/1 in the Eastern Atlantic in 2005 to study the distribution of the trace elements Hg (mercury), Pb (lead), Cd (cadmium), Cu (copper), Ni (nickel), Zn (zinc), Co (cobalt), Mn (manganese), Fe (iron), and Al (aluminium). With the exception of Hg, results were compared to earlier datasets from 1989 to 1990. The particulate fraction averaged over the transect was calculated to be 49% for Cd, 23% for Mn and 50% for Fe indicating a release of these TEI's (trace elements and their isotopes) from a leachable SPM fraction in the stored and acidified samples.Total Pb concentrations ranged between 5 and 20 pmol kg^? 1 in 2005 with highest values in the ITCZ (intertropical convergence zone). In 1989 Pb concentrations were twice as high in the region of the ITCZ, while by a factor of 10–15 higher values were obtained in the North Atlantic.Total Cd and Co are dominated, by different seasonal upwelling regimes (Equatorial upwelling, Guinea Dome, Angola Dome).Total Cu, Ni, Fe, Mn and Al show nearly identical concentrations in 1990 and 2005. For total manganese and aluminium strong maxima (3–4 nmol kg^? 1 and 55 nmol kg^? 1 respectively) are observed between 23°N and 0°, while the Fe maximum (6–9 nmol kg^? 1) is located at 7°N. Total Hg concentrations ranged between 0.5 and 4.5 pmol kg^? 1.     

Wave scattering by undulating bed topography in a two-layer ocean

The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed. U. BASU was born in 1949. She is a professor in the Department Applied Mathematics, Calcutta University, India. Her current research interests include water wave problems, continuum mechanics, etc.     

用超声波检测评定焊缝的不连续性

用超声波检测,根据测试的灵敏度,可获得焊缝不连续性的6个基本方面:(1)与标准反射物的回波信号相比较,从试样的反射波幅的大小可以近似地估计反射区的大小.     

美国铁路客车的发展动向与水平

文章阐述了美国地铁、高速列车等轨道车辆的发展水平、动态,以及铁道车辆市场现状。介绍了美国针对铁路事故而开展提高车辆强度、抗碰撞能力的研究及取得的成果。     

Empirical analysis on the effect of design variables of automotive seat lumbar support on the initial sitting discomfort

An empirical analysis was performed in order to examine whether the height of the lumbar support installed on the driver’s seat in a vehicle makes a difference to the initial discomfort when sitting, and among the design variables of the seat lumbar support, which one is the main variable that affects the initial discomfort most when sitting. The subjects who participated in this study were 50^th percentile male in their 30s and 40s from Korea and America, had driving experience, and had not experienced any back pain in the last 12 months. In order to figure out the level of discomfort felt by a driver depending on the movement or the shapes of the lumbar support, subjective sensibility evaluation was conducted and sitting body pressure was measured, and the change of lumbar spine angle was observed using X-ray image. Based on the results, design variables that affect the initial discomfort when sitting on a car seat and the correlation among these design variables were verified through statistical significance testing. The empirical analysis suggested that, among design variables of car seat lumbar support, the degree of prominence is the main variable that affects the initial discomfort when sitting for both Koreans and Americans, while the height and support width have very little to do with it.