小灌区农田土壤水分析

对山西省小灌区农田土壤水分在时空分布及其影响因素进行了分析.结果表明:大气降水、农田灌溉、作物蒸腾和田间土壤蒸发是影响土壤水分变化的主要因素.农田土壤水分分布随着作物的种类而变化.     

Defining the geochemical baseline: a case of Hong Kong soils

A geochemical baseline provides the means to distinguish between the pedogenic origin and the anthropogenic origin of the trace element in the environmental compartments. We collected 271 soil samples representative of different parent rocks and soil types from the whole territory of Hong Kong and analyzed the composition of clay mineralogy and the contents of 15 chemical elements (Fe, Cd, As, etc.) for these samples. The baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The result indicated that Fe was the best reference element for the normalization procedure among the five potential reference elements (Fe, Al, Sc, Ti, and Mn), followed by Sc and Ti. A poor correlation was found between Sc, Ti, and Cu. The predicted baseline was much lower than the A-value of the Dutch List used usually in screening the polluted soil of Hong Kong, implying that the extent of heavy metal pollution might have been underestimated with respect to local lands. We also applied the cluster analysis to distinguish the geochemical associations of the trace elements due to its importance to the baseline. Approximately three major associations including the Fe–Mn-oxides related, Al oxides or Al-bearing-clay-mineralogy related and sulfide- related associations were observed from the dendrogram.     

An assessment of land degradation in the Save catchment of Zimbabwe

The lack of reliable baseline information on land degradation is a hindrance towards its monitoring and mitigation. Of particular interest is the identification of areas susceptible to degradation. In this study, remote sensing and GIS technologies were applied to detect and map susceptibility to land degradation in Buhera district, in Save catchment, Zimbabwe. Data used included Landsat TM and ETM imagery for 1992 and 2002, agro-ecological zones, vegetation cover and population density. The study identified five preliminary categories of degradation susceptibility ranging from very high to low.     

A non‐baseline algorithm for damage locating in flexural structures using dynamic distributed macro‐strain responses

The concept of distributed strain‐sensing techniques has been proposed in our recent research, which was dedicated to utilizing the strain distributions throughout the full or partial areas of structures to detect arbitrary and unforeseen damage. An algorithm not requiring a detailed analytical model is presented for damage locating in flexural structures through the direct use of dynamic responses recorded by distributed long‐gauge strain sensors. The modal macro‐strain vector (MMSV), which has been proven to have a mapping relation with displacement mode shape, can be extracted directly from macro‐strain time‐series data, from which a damage evaluating index can be derived and used as an indicator for locating damage. Numerical examples are simulated to verify the sensitivity and effectiveness of the index in different cases. Furthermore, experimental investigations on a cantilevered beam with various long‐gauge fibre optic sensors placements are carried out to examine the feasibility and applicability of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.     

应用高分辨CT（HRCT）扫描弥补腔隙诊断之不足

目的：应用高分辨CT（HRCT）扫描方法，增加对头颅腔隙梗塞诊断的可靠性，材料和方法：对临床疑有腔隙的病人，在基底节区及可疑部位加用HRC扫描，遇到腔隙病灶与像素颗粒难以区分时在相同层面或上下1－2mm处做HRCT扫描。结果，有489例常规CT正常的病例哪现了腔隙灶，在遇到的502例不易诊断的可疑病灶中，经HRCT确诊的真正腔隙灶300例，伪腔隙（像素）202例，同时发现HRCT对正常脑组织结构的显示要较常规CT越得多，结论HRCT不仅能提高腔隙性梗塞的检出率，还能辨伪腔隙，是弥补常规CT对腔隙诊断不足的较好手段。     

黄土丘陵沟壑区小流域降雨入渗产流点面转化

在充分考虑小流域土壤入渗速率点面转化及地表结皮等影响因素在内的基础上 ,提出了小流域土壤入渗速率点面转化公式 :fm=fn×Sn/S×an×bn。以纸坊沟小流域为例 ,将实测的流域土壤入渗速率值 (点渗值 )利用上式进行转化 (面渗值 ) ,并与流域径流出口观测站由降雨径流观测值根据水量平衡原理推算出的面渗值进行对比 ,平均相对误差仅为 2 .42 %。初步得出流域土壤面渗率与不同治理度、年内 5～ 9月降雨总量间的单因子和复合因子高精度回归方程 ,为流域综合治理后的水资源量变化趋势提供一条量化途径     

Overview of US Minerals Management Service Activities in Deepwater Research

The US Minerals Management Service (MMS) is responsible for safe and environmentally sound management of offshore oil and gas resources. In recent years, there has been a tremendous increase in both activities and plans for deepwater development of these resources in the Gulf of Mexico (GOM). As the industry meets the enormous technical challenges involved, there is a concomitant effort to assure environmental protection of deep-ocean and coastal resources. This paper will outline the research planning and program currently underway to assess impacts, identify potential problems, and discover more about unknown resources of the deep ocean.     

伊舒断裂带南、北段震源参数研究

利用时间城小地震地震图的方法，研究了震源参数与介质特性的差异。据初步研究结果，伊通－舒兰断裂南、北两段的震源应力降与Ｑ值存在差异。该方法是断层的震源深度范围内介质特性研究的补充，为断裂的分段提供一个重要方法     

脑脓肿的CT诊断

作者报告了１００例脑脓肿，其中一般性脑脓肿６２例、脑内小脓肿３８例（强化灶小于１．５ｃｍ），并对发病部位，临床表现及ＣＴ表现的主要特点进行了讨论。     

一种适合定点使用的DTZ型质子旋进磁力仪

系统地介绍了ＤＴＺ系列质子旋进磁力仪的思路和性能特点，通过台站使用认为，ＤＴＺ系列仪器能满足地磁台观测精度的要求，具有实际使用的价值。