A comparison of three marine ecosystems surrounding the Korean peninsula: Responses to climate change

This study uses a comparative approach to examine responses of marine ecosystems to climatic regime shifts. The three seas surrounding the Korean peninsula, the Japan/East Sea, the East China Sea and the Yellow Sea represent three contiguous but distinct ecosystems. Sampling has been carried out by the National Fisheries Research and Development Institute of South Korea since 1965, using the same methods in all three seas. Sampling was generally synoptic. Amplitude time series of 1st EOF modes for temperature, salinity, zooplankton biomass and concentrations of four major zooplankton taxa were used to determine whether the three marine ecosystems respond in a similar manner to climate variations. Temporal patterns of the variables were strongly similar among the three seas at decadal time scales, but very weakly similar at interannual scales. All three seas responded to a climatic regime shift that occurred in 1989. Temperature, zooplankton biomass and copepod concentrations increased in the late 1980s or early 1990s in all three seas. Concentrations of amphipods, chaetognaths and euphausiids also increased in the Japan/East Sea and the East China Sea, but not the Yellow Sea. The Yellow Sea ecosystem differs strongly from the other two seas, and water exchange between the Yellow Sea and the East China Sea is much weaker than that between the East China Sea and Japan/East Sea. Spatial patterns of zooplankton determined by the EOF analysis were closely related to currents and fronts in each of the three seas.     

敦化市区地下水动态特征

本文按不同地下水类型,从地下水的水位、水温、水质三个方面论述了敦化市规划区地下水的动态特征。     

高地震区公路隧道地震动力响应分析

基于土一结构相互作用理论,对高地震区一实际重大工程的公路隧道洞口段结构进行了抗震计算,得到了衬砌结构各控制点的位移、加速度及内力响应规律。结果表明：在人工合成地震波条件下,衬砌墙脚、拱腰为抗震薄弱位置;结构的加速度波形与输入波形相似;这些结果为抗震设计提供了一些依据。     

地铁隧道结构变形监测信息管理系统的开发

地铁隧道结构变形监测的特殊性、周期性和长期性,使其信息量非常庞大.信息管理是地铁隧道结构变形监测中一项重要的工作,现有的管理方式效率很低.为了高效、准确地管理监测信息,及时分析预报地铁隧道结构的稳定状况,本文结合南京地铁运营期隧道结构变形监测实例,开发了一套具有变形监测资料存储、预处理、管理分析、可视化分析、预测预报及限值预警等功能的信息管理系统,保证了准确及时快速的数据处理和信息反馈,具有良好的运用和推广前景.     

自动化监测技术在我国首条大型电力隧道中的应用

通过自动化监测在超大工程项目中的应用,利用现有技术手段,对工程进行有效管理,逐渐将对工程的安全、预判起到越来越重要的作用,它可以在为工程节约大量资金情况下,提高预判安全施工的能力,是提高工程管理的重要手段。     

Overbreak and underbreak in underground openings Part 2: causes and implications

Summary The newly developed light sectioning method has been used to investigate some of the causes and costs of overbreak and underbreak. Investigations at the Aquamilpa Hydroelectric Project in Mexico have shown decreased overbreak and increased underbreak as a result of increased rock quality and decreased explosive energy. A new measure of explosive energy, the perimeter powder factor (PPF), has been defined and shown to be useful in the context of tunnel-wall rock damage. Tentative results indicate that explosive energy (PPF) may be a more important factor in producing underbreak, whereas rock quality may be a greater factor in producing overbreak. A site-specific equation is given for predicting overbreak or underbreak as a function of rock quality and explosive energy, with an evaluation of the cost of underbreak and overbreak.     

The origin of accretionary lapilli

Experimental investigations in a recirculating wind tunnel of the mechanisms of formation of accretionary lapilli have demonstrated that growth is controlled by collision of liquid-coated particles, due to differences in fall velocities, and binding as a result of surface tension forces and secondary mineral growth. The liquids present on particle surfaces in eruption plumes are acid solutions stable at 100% relative humidity, from which secondary minerals, e.g. calcium sulphate and sodium chloride, precipitate prior to impact of accretionary lapilli with the ground. Concentric grain-size zones within accretionary lapilli build up due to differences in the supply of particular particle sizes during aggregate growth. Accretionary lapilli do not evolve by scavenging of particles by liquid drops followed by evaporation — a process which, in wind tunnel experiments, generates horizontally layered hemispherical aggregates. Size analysis of particles in the wind tunnel air stream and particles adhering to growing aggregates demonstrate that the aggregation coefficient is highly grain-size dependent. Theoretical simulation of accretionary lapilli growth in eruption plumes predicts maximum sizes in the range 0.7–20 mm for ash cloud thicknesses of 0.5–10 km respectively.     

钻孔灌注桩施工对邻近运营隧道变形影响研究

桩基施工将引起周边地层位移和邻近隧道结构变形,以南京龙津桥改建项目桩基工程为背景,通过现场实测,分析研究钻孔灌注桩施工全过程各工况条件对地层位移场和邻近既有隧道结构变形的影响规律。结果表明:由于钢套管的护壁作用,钻孔灌注桩施工过程中产生的最大地层位移和隧道结构变形较小,说明采用“钢套管边旋压边取土”、“群桩间跳施工”等工艺,对周围土体扰动影响程度较小,建议近隧桩基工程采用全套管灌注桩的施工方法,监测分析结果可为类似工程提供技术参考。     

On the spatial characteristic of the short term and imminent anomalies of underground water behaviors before strong earthquake

Ｏｎｔｈｅｓｐａｔｉａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆｔｈｅｓｈｏｒｔ┐ｔｅｒｍａｎｄｉｍｍｉｎｅｎｔａｎｏｍａｌｉｅｓｏｆｕｎｄｅｒｇｒｏｕｎｄｗａｔｅｒｂｅｈａｖｉｏｒｓｂｅｆｏｒｅｓｔｒｏｎｇｅａｒｔｈｑｕａｋｅＸＵＥ－ＢＩＮＤＵ（杜学彬）...     

Assessment of sand encroachment in Kuwait using GIS

Assessment of sand encroachment in Kuwait using Geographical Information System (GIS) technology has been formulated as a Multi-Criteria Decision Making problem. The Delphi method and Analytical Hierarchy Process were adopted as evaluating techniques, in which experts’ judgments were analyzed for objectively estimating and weighting control factors. Seven triggering factors, depicted in the form of maps, were identified and ordered according to their priority. These factors are (1) wind energy; (2) surface sediment; (3) vegetation density; (4) land use; (5) drainage density; (6) topographic change and (7) vegetation type. The factor maps were digitized, converted to raster data and overlaid to determine their possible spatial relationships. Applying a susceptibility model, a map of sand encroachment susceptibility in Kuwait was developed. The map showed that the areas of very high and high sand encroachment susceptibility are located within the main corridor of sand pathway that coincides with the northwesterly dominant wind direction.