Fundamental study on the response characteristics of drivers during an earthquake based on driving simulator experiments

After the 1995 Kobe earthquake, the expressway structures in Japan were retrofitted and they will not now be seriously damaged under a certain level of strong earthquake motion. However, the stability of a moving vehicle has not been investigated yet. It has been reported that drivers feel seismically induced vibrations, especially in the transverse direction of vehicles. Owing to this phenomenon, drivers have some difficulty in controlling the vehicles during strong shaking. For further safety promotion of the expressway networks, it is important to understand the drivers' reactions to seismic motion. The present authors have performed a series of seismic response analyses of a moving vehicle to investigate its response characteristics based on numerical simulation. However, the responses of the driver were not considered in the simulation process. In order to investigate the drivers' reactions during an earthquake, a series of virtual tests were conducted using a driving simulator. This driving simulator has six servomotor‐powered electric actuators that control its motions. Several types of tests were carried out for different examinees to investigate drivers' responses while controlling the simulator under seismic motion. The results of this study showed that a larger response time lag to strong shaking and over turning of the steering wheel may shift the vehicle into the next lane. According to this finding, trafficaccidents could possibly occur under strong ground shaking in the case of heavy traffic. Copyright © 2004 John Wiley & Sons, Ltd.     

Dynamic response of partially sealed circular tunnel in viscoelastic saturated soil

Based on Biot's wave equation, dynamic response of a circular tunnel with partially sealed liner in viscoelastic saturated soil is investigated. By introducing two scalar potential functions, the analytical solutions of stresses, displacements and pore pressure induced by axisymmetric gradually applied step load are derived in Laplace transform domain. Numerical results are obtained by inverting Laplace transform presented by Durbin and used to analyze the influences of partial permeable property of boundary and viscoelastic damping coefficient of soil on dynamic response of the tunnel. It is shown that the attenuation of radial displacement appeared with the increase of viscoelastic damping coefficient of soil, and relative rigidity of liner and soil, and the influence of partial sealing property of boundary on stresses, displacements and pore pressure is remarkable. The available solutions of permeable and impermeable boundary conditions are only two extreme cases of this paper.     

钱家店铀矿床U-Ra平衡系数特征研究

本文探讨了可地浸砂岩型铀矿U-Ra平衡系数的计算方法，研究了钱家店砂岩型铀矿床U-Ra平衡系数的变化特征。这些成果为钱家店铀矿床放射性测井数据的修正、矿体边界的确定、铀矿资源量的计算提供了科学依据。     

描述黄河中下游河道横断面形态的新指标

描述河流横断面的窄深程度,无非是用来衡量它对过流能力和输沙能力的影响大小,及其在河流地貌方面的时空上的调整变化。回顾总结了以往描述横断面形态的常用指标,包括河相系数、宽深比,或湿周与平均水深的比值,指出这几种指标在描述黄河中下游河道时所存在的共同缺点:(1)缺乏物理意义;(2)不能真正代表断面的窄深程度;(3)明显的夸大了宽浅和窄深断面的差别。从表称流量的概念出发,作者认为,应该使用具有明确物理意义的等面积的表称流速来描述断面形态。如果用表称流速来衡量黄河下游河南和山东河道的断面形态的差别,就会发现,断面形态的不同,其对过流能力的影响不过1:2,远不象河相系数和宽深比所描述的达到1:6甚至1:11那样的悬殊程度;黄河下游河道主槽“多来多排”的主要影响因素是表称流速。     

Variation of the plasma turbulence in the central plasma sheet during substorm phases observed by the interball/tail satellite

Fluctuations of the plasma bulk velocity across the plasma sheet are studied using single-point measurements from the Corall instrument on board the Interball/Tail satellite. Several hour-long intervals of continuous data corresponding to quiet geomagnetic conditions and different phases of isolated substorms are analyzed. The plasma sheet flow appears to be strongly turbulent, i.e. dominated by fluctuations that are unpredictable. Corresponding eddy diffusion coefficients were obtained as a function of the autocorrelation time and rms velocity of the fluctuations. It was found that the amplitude of the turbulence and the values of eddy-diffusion coefficients increase significantly during substorm growth and expansion phases and they decrease to their initial level during the recovery phase. We also studied a relationship between the eddy-diffusion coefficients and the absolute value of the geomagnetic field, also measured by the Interball/Tail satellite. It was found that this relationship varies depending on the phase of substorm, indicating possible change in the turbulence regimen with substorm phase.     

Towards a long-term monitoring of Central European water mite faunas (Acari: Hydrachnidia and Halacaridae) – considerations on the background of data from 1900 to 2000

The state of knowledge of the Central European water mite fauna and the research history are briefly surveyed. Several areas for which we are provided with rich data sets are of high value for the monitoring of faunistic trends on the background of local and global environmental change. The need for a database combining historical and actual faunistic information is stressed. It should facilitate the access to all data from former times, give a survey on actual activities by regular updates, and help for a better organization of future research activities. On the base of an update of the Limnofauna Europaea (K.O. Viets 1978, Gerecke in www.watermite.org) a first attempt is made to (1) recognize changes in the Central European fauna during the past 100 years; (2) emphasize species which may be endangered or have disappeared during the past 100 years. At the present state of knowledge, the degree of threat to water mite species in this area is best calculated from their preference for particular habitat types which are rare and in danger to disappear in cultivated landscapes. Our knowledge concerning neozoic water mites in the study area is discussed.     

Under stress permeability determination of the Meuse/Haute-Marne mudstone

In the underground waste isolation projects such as the ANDRA'one in the site of Bure, the transport properties of the surrounding rock mass is of fundamental importance. To measure very low permeability, we use the modified version of the pulse test proposed by Hsieh et al. [Hsieh, P.A., Tracy, J.V., Neuzil, C.E., Bredehoeft, J.D., Silliman, S.E., 1981. A transient laboratory method for determining the hydraulic properties of ‘tight’ rocks — I. Theory. Int. J. Rock Mech. Min. Sci. Geomech. Abstr. Vol. 18, pp. 245-252] which enables the intrinsic permeability, k, and the specific storage coefficient, S_s, of rocks such as mudstone to be characterized. In this paper, the special effort performed on the laboratory apparatus design, to ensure a good sensitivity of the rock response with respect to both parameters, k and S_s, is presented. In addition, two parameters identification procedures are proposed: the graphical method given by Hsieh et al. [Hsieh, P.A., Tracy, J.V., Neuzil, C.E., Bredehoeft, J.D., Silliman, S.E., 1981. A transient laboratory method for determining the hydraulic properties of ‘tight’ rocks — I. Theory. Int. J. Rock Mech. Min. Sci. Geomech. Abstr. Vol. 18, pp. 245-252] and a parameter identification based on the solution of an inverse problem. The efficiency of the apparatus design and the parameters identification procedures is then demonstrated though some pulse tests performed on the Meuse/Haute-Marne mudstone.     

273.15K下LiCl-Li2B4O7-H2O体系热力学性质的等压研究

用等压法研究了273 15K下LiCl-Li2B4O7-H2O体系中纯盐水溶液(离子强度范围为LiCl0 2046～2 5055mol·kg-1,Li2B4O70 1295～0 3700mol·kg-1)以及混合盐水溶液(离子强度范围为0 0931～2 4911mol·kg-1)渗透系数和水活度;计算了LiCl-Li2B4O7-H2O体系的饱和蒸汽压,获得饱和蒸汽压、渗透系数随离子强度的变化规律。用实验数据以最小二乘法求取了LiCl和Li2B4O7纯盐参数及体系的混合盐参数,拟合的标准偏差分别为0 0077和0 026。用该模型计算的渗透系数值与实验结果取得合理的一致。同时研究结果与273 15K下LiCl-Li2SO4-H2O体系的渗透系数随离子强度变化的规律作了比较。本研究对完善低温下含锂、硼盐湖卤水体系的热力学模型和盐湖资源的综合开发利用具有重要意义。     

Impact of deforestation on pearl mussel habitats in the Russian section of the Baltic Sea basin

Changes in the vegetation cover associated with intensive forest extermination may have a strong effect on the riverine environment, including the chances of survival for bivalve mollusc populations in small streams and rivers. In order to check this hypothesis, drainage area properties of the rivers with extinct and existing pearl mussel populations in the Russian section of the Baltic Sea basin were compared. Preservation of forest vegetation along the river banks of the studied rivers was correlated with the presence of pearl mussel populations. Traditional agriculture turned out to be, in some cases, more harmful for river ecosystems than urbanization and industrialization.     

内蒙古河套灌区春玉米作物系数试验研究

作物系数曲线是估算作物生长季耗水量变化的重要参数。基于2013年4—9月内蒙古巴彦淖尔市临河区田间水分试验和1994—2013年气象站观测资料,利用水量平衡法反求春玉米作物系数,分析生长季内的变化规律, 建立动态模拟方程,并与联合国粮农组织 (FAO) 分段直线法结果进行比较, 提出胁迫条件下作物系数的叶面积修正方法。结果表明:玉米作物系数随发育进程可用三项式曲线描述,变化趋势与产量水平无关, 但随产量增高而变幅增大;以出苗后相对积温为时间变量建立模拟方程效果较好,决定系数 (R2) 均在0.92以上;模拟计算出各站点最大 (1.30~1.48) 和平均 (0.831~0.919) 作物系数,与FAO分段直线法计算的典型值和区间值基本一致,生长中期平均相对误差为3.4%~7.2%;提出利用相对叶面积指数修正作物系数的计算方法;通过2014年实例检验,土壤水分模拟值与实测值的平均相对误差为6.3%,相对误差小于15%的占95.8%。