A brief history of the solar oblateness. A review

We hereby present a review on solar oblateness measurements. By emphasizing historical data, we illustrate how the discordance between experimental results can lead to substantial improvements in the building of new technical apparatus as well as to the emergence of new ideas to develop new theories. We stress out the need to get accurate data from space to enhance our knowledge of the solar core in order to develop more precise ephemerids and ultimately build possible new gravitational theories.     

一种应用于三峡滑坡探测的新方法-SNMR法

三峡库区蓄水后,由于水位上升滑坡地区的软弱层遇到水就会变软并引起滑塌。核磁共振是当今世界尖端技术之一,我们首先将该技术应用于滑坡探查。本文探讨了用SNMR探查滑坡的方法技术以及通过SNMR实测数据求取与滑坡稳定性有关的水文地质参数,通过一个三峡的实例说明了该方法是一种快速有效的探测滑坡的方法。     

OPERATING A LIMESTONE AQUIFER AS A RESERVOIR FOR A WATER SUPPLY SYSTEM

Abstract

An aquifer can be used not only as water source but also as a regulating reservoir linked to a water supply system, planning the operation of such reservoirs calls for a good knowledge of the characteristics and limitations of the aquifer, an estimate of its natural replenishment and outflows, as weil as the determination of a programme for pumping and artificial recharge.

A limestone aquifer of karstic nature, heavily exploited and artificially recharged, has been studied recently with respect to its storage capacity and responses to a planned scheme of operations established for the national water supply systems.

The physical characteristics of this aquifer, its inflows, outflows and dynamic behaviour, were first determined by geological and hydrological investigations. The dynamic model obtained was then verified and improved by use of a resistor-capacitor electric analog constructed for this purpose. Later on, several operational alternatives were tested on the same analog. An optimization analysis was performed on a simplified single cell model representing the aquifer system. The methodology of such integrational operation is discussed in light of the results obtained.     

A HYDROLOGICAL MODEL STUDY OF A FORESTED AND A CUTOVER SLOPE

ABSTRACT

The problem of analysing and predicting the effect of vegetation removal on the hydrological regime or soil water potential on steep slopes was approached through an experimental model set up in a greenhouse. A tilting soil bin positioned at different slope angles simulated a soil layer overlying impervious bedrock, and a forest cover was modelled by a number of small trees. The response of the soil water potential to simulated rain storms was studied first for the forested and later for the cutover slope. Transpiration in the greenhouse was measured by means of phytometers.

The results showed that a forest cover accelerates the soil moisture depletion in a shallow soil mantle regardless of the steepness of the slope. For a storm of given intensity and duration, the recharge phase for the clear-cut slope was therefore much shorter than for the forested one. The slope angle was only responsible for the distribution of recharge and the initial hydrological conditions when drainage had ceased. During the drainage phase the flow in the slope was two-dimensional, whereas it was essentially one-dimensional (i.e. vertical upwards) after field capacity had been reached. At this point the matric suction increased exponentially with time for suctions within the tensiometer range. Within this same range water loss from any point in the soil took place at a constant rate. This result is consistent with field observations.     

关于公元649年临汾地震的讨论

唐贞观２３年８月癸酉（公元６４９年９月１２日）河东（黄河以东,今山西省境）地震,晋州（治临汾,今临汾市）尤甚。对此次地震事件的烈度等一直存在不同看法。     

A comparison of integrated river basin management strategies: A global perspective

In order to achieve the integrated river basin management in the arid and rapid developing region, the Heihe River Basin (HRB) in Northwestern China, one of critical river basins were selected as a representative example, while the Murray–Darling Basin (MDB) in Australia and the Colorado River Basin (CRB) in the USA were selected for comparative analysis in this paper. Firstly, the comparable characters and hydrological contexts of these three watersheds were introduced in this paper. Then, based on comparative studies on the river basin challenges in terms of the drought, intensive irrigation, and rapid industrialization, the hydrological background of the MDB, the CRB and the HRB was presented. Subsequently, the river management strategies were compared in three aspects: water allocation, water organizations, and water act and scientific projects. Finally, we proposed recommendations for integrated river basin management for the HRB: (1) Water allocation strategies should be based on laws and markets on the whole basin; (2) Public participation should be stressed by the channels between governance organizations and local communities; (3) Scientific research should be integrated into river management to understand the interactions between the human and nature.     

一种浅水湖耦合模式系统的发展与应用

Growing developments in lake basins in China, have adversely affected, the water quality of lake, in particular, the water bodies of many famous shallow lake are seriously polluted in recent years. Some projects have been built up to improve the water quality, for example, the sewage interception project (i.e. Xiyuan tunnel project) and four sewage treatment plants etc. have been built up in Dianchi Lake. In order to predict and evaluate the effects of projects on the water quality, it is necessary to develop a coupled model system, which should mainly include wind, circulation and water quality parameters. This paper describes the development and application of a coupled modeling system in a shallow lake, which include a 3D micro-meteorology model (3DMM), a 2D hydrodynamic model (2DHM) and a 2D water quality model(2DWM).The coupled modeling system has been applied to predict the ejfects of environmental protection projects on water quality in Dianchi Lake.     

地形表面反射强度的数学层析成像方法

若二维ＲＦ窄波反射函数是定义在地面一圆形区域内部的，并假定该圆域表面介质是弱反射介质，那么在给定时刻，接收发射器（如机载合成孔径雷达）所接收到的近回数据可视 过该圆域的一圆弧上的线积分值，Ｍｕｍｓｏｎ，ｅｔ，ａｌ。在假定圆域半径与接收发射器运动路径到该圆域中心的距离相比很小的情况，用直线上的线积分值来代替圆弧线上的线积分值，利用古典的Ｒａｄｏｎ变换方法，给出了该圆域反射函数的成像模式。本文将克服这     

A MATLAB implementation of TOPMODEL

The MATLAB SIMULINK programming language is applied to the TOPMODEL rainfall–runoff model. SIMULINK requires a good recognition of model dynamics, which has been achieved here in a version based on the first TOPMODEL (Beven and Kirkby, 1979). Introducing the topographic index distribution in a vector form allows the generalization and simplification of the SIMULINK structure. The SIMULINK version of TOPMODEL has a very easy to understand graphical representation, which shows, in a straightforward way, all the physical interactions that take place in the model. Moreover, owing to its modular structure it is easy to add new and/or develop old submodels, depending on the available data and the goal of the modelling. In the example given here TOPMODEL was extended by two submodels representing the soil moisture and evaporation distribution in the catchment. Preparation of the data and presentation of the results is done in MATLAB. Discharge predictions and spatial patterns of hydrological response are demonstrated for a separate validation period. © 1997 John Wiley & Sons, Ltd.     

前震研究进展综述

介绍了当前国内外前震研究领域的一些进展。 对比了不同前震定义条件下前震序列的共性特征, 对几种主要的前震机理及主要的前震识别方法进行了简要综述, 对其特点及存在的问题进行了评述和讨论。 前震指主震之前在主震断层面上、 紧邻主震破裂起始点发生的小地震。 主震发生之前的一系列前震活动构成前震序列。 在不同的前震定义条件下, 具有“直接前震”的震例比例从10%至40%不等。 理论上前震可用级联应力触发或预滑动模型进行解释。 前震空间上主要集中分布在距离主震10~75 km范围内, 但其时间分布形式复杂, 大多发生在主震前1~2天, 部分前震序列的地震活动率显示明显的加速特征, 但许多前震序列单独来看却往往显示主-余型序列的衰减特征。 序列地震震源机制一致、 序列b值偏低是前震序列最突出的特征。 前震的发生与主震破裂形式和构造环境似有一定关系, 在有限的前震震例中, 逆冲型主震似乎具有相对较多的前震。 部分震例的研究结果显示, 随主震的临近, 前震震源深度有逐渐下迁的特点。 到目前为止, 震前很难判定一次地震或一个地震序列是否为前震或前震序列, 所使用的前震识别主要有基于统计类比的方法、 基于震源机制一致及衍生的相关方法以及基于对地震成核过程精细检测的方法。 从现有不多的震例研究结果来看, 尽管地震时空丛集和震源机制高度一致是前震序列的最显著特征, 但却不是判定前震序列的充分条件。 由于成核的破裂扩展速度和滑动位移有随时间较快增大的趋势, 因而基于对地震成核过程精细检测的方法有望在前震识别中发挥更为重要的作用, 但需更多震例进行验证。     

一次地震预测的案例

2001年11月14日昆仑山8.1级地震后, 川滇地区的震情引起了地震学者的普遍关注。 文中详细阐述了针对当时川滇地区的多种地震与地震前兆观测项的观测异常形成的综合预测意见及预测三要素的判定, 并探讨了8.1级地震对这一预测意见的影响及对经验性地震预报的认识。     

A RENEWED JOURNAL FOR A NOVEL ASSOCIATION

The International Journal of Sediment Research (edited, published and distributed by IRTCES) has, since a long time, been a valuable tool for circulating technical and scientific results in the field of erosion and sedimentation. With the present issue the Journal has become the official publication of WASER. What will this affiliation imply for the journal itself and for the readership ?     

Damping and response measurement on A small-scale model of A cable-stayed bridge

A small-scale model of an existing cable-stayed bridge has been designed and built. Hammer, sinusoidal and random signal tests have been performed to determine the dynamic characteristics of the model. An attempt has been made to evaluate the real effect of the vibration of stays upon system damping. Initial measurements have been performed for a model where there was no vibration of the stays because of the absence of appropriately scaled additional mass of these stays. In this way the effect of the cables was eliminated in damping measurement. During the second series of measurements appropriate mass has been added to the stays, causing them to take part in the vibration. The comparison of the measured damping of the model for each case makes possible the estimation of the effect of the stays upon the system damping. By using the shaking table, two types of seismic excitation were applied, with corresponding response quantities in the critical sections being measured. Good agreement between the analytical and the experimental results was achieved.