加速器质谱法测定深海锰结核样品中的^10Be

本文研究深海锰结核中＾１０Ｂｅ的加速器质谱法分析。提出了ＮａＯＨ和ＥＤＴＡ分离纯化－ＢｅＯ制样－加速器质谱法测量＾１０ＢｅＯ制样－加速器质谱法测量＾１０Ｂｅ的分析程序。研究结果表明,该法回收率较高,分离效果较好,按该法制备的ｅＯ靶能较好地满足加速器质谱法对测量＾１０Ｂｅ的要求。利用该法测得北太平洋两个锰结核的生长速率分别为２．７ｍｍ／Ｍａ和１．５ｍｍ／Ｍａ。这些结果与其他研究者所测数据相比,非常一     

Field experiment of subgrade vibration induced by passing train in a seasonally frozen region of Daqing

The vibration characteristics and attenuation of the subgrade caused by passing trains in a seasonally frozen region of Daqing, China are investigated. Three field experiments were conducted during different times through the year, in normal, freezing and thawing periods, respectively, and the influence of the season, train speed and train type, is described in this paper. The results show that: (l) the vertical component is the greatest among the three components of the measured vibration near the rail track, and as the distance to the railway track increases, the dominant vibration depends on the season. (2) Compared with the vibration in the normal period, the vertical and longitudinal vibrations increase while the lateral vibration decreases in the freezing period. However, in the thawing period, the vertical and longitudinal vibrations decrease, and the lateral vibration increases. (3) As train speeds increase, the subgrade vibration increases. (4) The vibration induced by a freight train is greater than by a passenger train. These observations provide a better understanding of the vibration and dynamic stability of the subgrade and may be useful in developing criteria for railway and building construction in cold regions.     

塔里木盆地南部中生代碰撞相关构造及其在古特提斯研究中的意义

地震资料解释和野外地质调查,在塔里木盆地南部发现中生代碰撞相关构造.同碰撞构造发育于西昆仑山前、阿尔金山前和麦盖提斜坡,为晚三叠世冲断构造.既有晚三叠世新形成的冲断构造,也有先存构造的复活(如车尔臣断裂).碰撞后构造见于西昆仑和阿尔金山前,是一些规模不大的侏罗纪—白垩纪正断层及其控制下形成堑—垒构造.晚三叠世构造应力场...     

福州市土地利用景观格局分析

以福州市土地利用现状图为基本图件,在GIS支持下编制了福州市土地利用景观图,进而选取几种主要指数,通过Excel软件计算,定量分析了福州市土地利用的景观格局及破碎化特征.结果表明林地为基质景观,优势度指数最高,分离度指数最低;耕地、园地、城镇村及工矿用地和水域的均匀度较高,多样性指数较大,但破碎化程度较深;未利用地破碎度最低.从总体上看,土地利用的景观比较单调、多样性指数较小、破碎化程度也较低,景观异质性不高.     

高压摆喷灌浆技术在西藏病险水库大坝防渗中的设计与施工

在西藏高原地区第四系冰碛和湖积松散堆积层防渗加固中,针对高原特殊的气候条件、工程地质与水文地质条件,通过改进高压摆喷设备与工艺,优化设计参数,取得了较好的防渗加固效果。工程实例表明,在高寒冻融地区,采用高压摆喷灌浆防渗加固技术,对砂砾石土坝进行加固处理,技术可靠,经济合理,效果明显,是一种有效的防渗处理方法,值得在高原地区进一步推广使用。     

碎石桩加固液化场地高桩码头抗震性能分析

针对经典离心机振动台试验,构建液化场地高桩码头三维数值模型,并验证数值模型的正确性。在此基础上,系统研究加固区距码头的距离、碎石桩直径和长度等参数对液化场地高桩码头加固效果的影响,揭示了不同加固参数下液化场地高桩码头变形受力规律。研究发现：液化场地高桩码头抗震性能与这些参数呈正相关,并且大直径和长尺寸碎石桩可以有效地控制地震过程中高桩码头的水平位移和桩身弯矩。研究工作对液化场地高桩码头地基加固具有重要借鉴意义。     

江雄水库新建大坝渗漏成因分析与处理

江雄水库蓄水初期,随着库水位逐渐上升,观测孔内水位高,坝下游陆续出现的渗漏量不断增大,量水堰最大渗漏量达到300 L/s的异常现象,影响大坝安全。通过大坝监测系统、电法探测、连通试验等成果,分析了坝基、绕坝、溢洪道、输水洞等渗漏主因,查找到主要渗流通道,为大坝堵漏处理方案设计提供了决策依据。还提出了安全渗流对保护下游生态有巨大作用的观点。     

Spatiotemporal characteristics,patterns and causes of land use changes in China since the late 1980s简

Land-use/land-cover changes （LUCCs） have links to both human and nature inter- actions. China＇s Land-Use/cover Datasets （CLUDs） were updated regularly at 5-year inter- vals from the late 1980s to 2010, with standard procedures based on Landsat TM／ETM＋ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes （LUCs） across China indicated a significant variation in spatial and temporal characteristics in the last 20 years （1990-2010）. The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included （1） an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; （2） shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; （3） continuous transformation from rain-fed farmlands in northeast China to paddy fields; and （4） effective- ness of the ＂Grain for Green＂ project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change in the north affected the change in cropland, policy regulation and economic driving forces were still the primary causes of LUC across China. During the first decade of the 21st century, the anthropogenic factors that drove variations in land-use pat- terns have shifted the emphasis from one-way land development to both development and conservation. The ＂dynamic regionalization method＂ was used to analyze changes in the spatial patterns of zoning boundaries, the internal characteristics of zones, and the growth and decrease of units. The results revealed ＂the pattern of the change process,＂ namely the process of LUC and regional differences in characteristics at different stages. The growth and decrease of zones during this dynamic LUC zoning, variations in unit boundaries, and the characteristics of change intensities between the former and latter decades were examined. The patterns of alternative transformation between the ＂pattern＂ and ＂process＂ of land use and the causes for changes in different types and different regions of land use were explored.     

浅议房产测绘制图、面积分摊系统的开发

本文针对房屋分层分户面积测算特点，设置三个级别功能模块及流程，运用灵活方便的绘图与编辑功能，采集面积自动校验功能及合理的分摊方法、步骤，科学合理地开发出一套方便实用，面积分摊计算和管理系统。