The age of the Nantuo Formation and Nantuo glaciation in South China

A U–Pb sensitive high‐resolution ion microprobe (SHRIMP) age of 654.5 ± 3.8 Ma from an ash bed immediately below the Nantuo Formation in South China provides the lowest age constraint for the Nantuo glaciation, which has been correlated with the global ‘Marinoan’ glaciation. A U–Pb SHRIMP age of 636.3 ± 4.9 Ma from a fallout tuff within the basal layer of the Nantuo Formation, along with the existing age of 635.2 ± 0.6 Ma from its overlying Doushantuo cap carbonate, suggests that the traditionally defined Nantuo Formation may have been deposited in a short time period at the end of the Nantuo glaciation. In combination with available ages globally, the data support a relatively short duration and rapid termination of ‘Marinoan’ glaciations.     

Interference of Multiple Strip Footings on Sand Using Small Scale Model Tests

By using small scale model tests, the interference effect on the vertical load-deformation behavior of a number of equally spaced strip footings, placed on the surface of dry sand, was investigated. At any stage, all the footings were assumed to (i) carry exactly equal magnitude of load, and (ii) settle to the same extent. No tilt of the footing was permitted. The effect of clear spacing (s) among footings on the results was explored. A new experimental setup was proposed in which only one footing needs to be employed rather than a number of footings. The bearing capacity increases continuously with decrease in spacing among the footings. The interference effect becomes further prominent with increase in soil friction angle. In contrast to an increase in the bearing capacity, with decrease in spacing of footings, an increase in the footing settlement associated with the ultimate state of shear failure was observed. The present experimental observations were similar to those predicted by the available theory, based on the method of characteristics. As compared to the theory, the present experimental data, however, indicates much greater effect of interference especially for larger spacing among footings.     

Analysis of the 2003 Varunawat Landslide,Uttarkashi, India using Earth Observation data

Mass movements such as landslides in mountainous terrains are natural degradation processes and one of the most important landscape-building factors. Varunawat Parbat overlooking Uttarkashi town witnessed a series of landslides on 23 September 2003 and the debris slides and rock falls continued for 2 weeks. This landslide complex was triggered due to the incessant rainfall prior to the event, and its occurrence led to the blockage of the pilgrim route to Gangotri (source of the Ganges river) and evacuation of thousands of people to safer places. Though there was no loss of lives due to timely evacuation, heavy losses to the property were reported. High-resolution stereoscopic earth observation data were acquired after the incidence to study the landslide in detail with emphasis on the cause of the landslide and mode of failure. Areas along the road and below the Varunawat foothill region are mapped for landslide risk. It was found that the foothill region of the Varunawat Parbat was highly disturbed by man-made activities and houses are dangerously located below steep slopes. The potential zones for landslides along with the existing active and old landslides are mapped. These areas are critical and their treatment with priority is required in order to minimise further landslide occurrences.     

Finite Element Modeling of Swelling Soil Pressures Using Joint/Interface Elements

There could be some discontinuities in a soil media such as layers, earth structures, cracks, and fissures so that estimation of stresses and deformations in these types of soil masses are somewhat different from continuous masses. The discontinuities in a soil mass could be considered as a special link between two blocks. Transmitted swelling pressures affected by the soil properties of the backfill especially at the interface between the backfill and retaining wall. In order to estimate the transmitted swelling pressure distribution behind a retaining wall, using with interface element, a new finite element model and a code (SWELPRES) have been developed. To evaluate the effect of backfill characteristics and interface element from the transmitted lateral swelling pressures, four cases of thickness of backfills with or without interface elements are investigated.     

Monitoring Large-Scale Tests for Nuclear Waste Disposal

Two large-scale “in situ” demonstration experiments and their instrumentation are described. The first test (FEBEX Experiment) involves the hydration of a compacted bentonite barrier under the combined effect of an inner source of heat and an outer water flow from the confining saturated granite rock. In the second case, the progressive de-saturation of Opalinus clay induced by maintained ventilation of an unlined tunnel is analyzed. The paper shows the performance of different sensors (capacitive cells, psychrometers, TDR’s) and a comparison of fill behaviour with modelling results. The long term performance of some instruments could also be evaluated specially in the case of FEBEX test. Capacitive sensors provide relative humidity data during long transient periods characterised by very large variations of suction within the bentonite.     

基于呼叫中心的防伪识别系统的设计与实现

呼叫中心系统是综合利用先进的通信及计算机技术,对信息和物资流程优化处理和管理,集中实现沟通、服务和生产指挥的系统.介绍了呼叫中心系统的历史、发展过程、意义等,阐明了论文的研究背景和主要的研究工作.论述了呼叫中心的基本原理,以及本系统总体方案的确定和相关技术,并详细阐述了系统的具体实现方法.本系统结合实际需求,采用板卡实现方案,有效地提高了系统的性能价格比,解决了呼叫中心在电话防伪识别系统中所涉及的相关问题.通过实践运行该电话防伪识别系统,证实了该系统的实用性和有效性.     

天津地面沉降区土水比论述

天津市地面沉降分布广,沉降速率大。本文针对当前地面沉降研究和防治过程中所遇到的勘查资料严重缺乏、禁采难以全面实现等难题,提出了土水比指标量。通过概念分析和对多年数据的分析,认为土水比可以检验地下水开采量数据的统计精度,指示地下水资源补给及土层释水条件,并表明沉降的严重程度,反映地下水资源的保障程度。建议在沉降防治工作中,以土水比作为指标,通过相关分析模型来制定压采量。     

分光光度法测定海洋河弧菌510脂多糖

本文研究了直接测定海洋河弧菌 (vibrio fluvailis) 5 10脂多糖的分光光度法。利用 1,9-二甲基亚甲蓝 (DMB) ,在适当条件下同脂多糖发生染色反应 ,在 5 5 0 nm波长下 ,反应体系的吸光值同脂多糖含量呈线性相关。相关系数为 0 .9993,最低检出限为 10 μg/m L,相对标准偏差为 1.6 2 ,平均回收率为 (10 5± 2 .18) %。     

中国对虾血细胞酶细胞化学的初步研究

运用电镜酶细胞化学技术 ,对中国对虾 (Penaeus chinensis)的血细胞和血清中的酚氧化酶、酸性磷酸酶、碱性磷酸酶和过氧化物酶的酶活性部位进行标记。实验结果显示 :酚氧化酶主要以酶原形式存在于大颗粒细胞的颗粒体中 ,酸性磷酸酶和碱性磷酸酶以酶原形式存在于小颗粒细胞的颗粒体中。健康虾和患病虾血细胞中酶活性的表现形式不尽相同 ,在病理情况下 ,颗粒细胞能以细胞解体的方式 ,排出细胞内的颗粒 ,转化成有活性的酶 ,以此提高血淋巴中这几种酶的活性。透明细胞可以吞噬排放颗粒后的颗粒细胞 ,透明细胞中由高尔基体合成的酸性磷酸酶等溶酶体酶主要用于透明细胞的细胞内消化作用。研究认为 :3种血细胞因含有不同的免疫酶以及酶的作用方式不同而具有不同的免疫功能     

中太平洋西部深海沉积物中的火山碎屑与粘土矿物

对于太平洋深海沉积物的研究虽有很久的历史(如1873-1876年“挑战者”号的科学考察),但对该区开展深入系统的岩石学和矿物学研究却是六十年代以后的事.随着研究手段的发展和进步,已积累了关于该区深海沉积物的大量资料.目前我国的海洋工作者也正在努力开展这方面的科学研究工作.