人类活动对河北平原地下水水质演化的影响   总被引：14，自引：1，他引：14       下载免费PDF全文

毕二平  母海东  陈宗宇  王昭 《地球学报》2001,22(4):365-368

广大的平原地区和主要城市地区地下水水质的变化状况可以说明，人类活动引起了河北平原地下水化学组分的改变，其中硬度是一个普遍升高，且超标的化学组分，因此，认为硬度是反映人类活动对地下水影响的特征性化学指标，人类活动引起地下水的明显污染可以由铵来表征，通过对地下水硬度升高原因的分析，论述了人类活动影响地下水水质演化的基本机理。  相似文献   

氯与硫酸根比值对硫酸盐渍土工程性质影响的研究   总被引：8，自引：0，他引：8  

杨丽英  李斌 《冰川冻土》1997,19(1):84-89

对含氯化钠硫酸盐渍土的盐胀量，液限，塑限进行了试验分析，提出了不同硫酸钠含量水平下氯与硫酸根比值，即Ｃｌ＾－／ＳＯ４＾２－与盐胀率，Ｃｌ＾－／ＳＯ４＾２－与液限、塑限之间的计算公式，对从Ｃｌ＾－／ＳＯ４＾２－角度评判盐渍土的工程性质具有一定参考意义。  相似文献   

利用浮石合成13X型分子筛最佳工艺条件的研究     

金为群  权新军  蒋引珊  张军 《吉林大学学报(地球科学版)》1997,(2)

以吉林省长白山地区的天然浮石为原料，成功地合成了１３Ｘ型分子筛，对其合成路线，反应条件进行了研究，确定了合成１３Ｘ型分子筛的最佳工艺条件，并通过Ｘ射线衍射法及差热分析等手段证明了产物的结构  相似文献   

Chocolate in China: the cadbury experience     

L.J. Wood  S. Grosvenor 《The Australian geographer》1997,28(2):173-184

Since 1979, China's Open Door policy has attracted increasing foreign investment. To maintain global competitiveness, the British confectioner, Cadbury, authorised its Australian subsidiary to develop a chocolate plant in China. This paper details the decision‐making processes that eventually led to a new factory on a greenfield site near Beijing. It also illustrates some of the adaptations that Cadbury has had to make in its product and production procedures in order to match its own standards for dairy milk chocolate and yet accommodate guo qing (the special situation in China).  相似文献   

Late holocene environmental change in an upper Montane area of the snowy mountains,New South Wales     

S.D. Mooney  J.R. Watson  J.R. Dodson 《The Australian geographer》1997,28(2):185-200

This study examines environmental change in the upper montane zone of the Australian Eastern Highlands during the late Holocene, by analysing vegetation, fire and erosion records contained within a small fen located in a frost hollow. Differences in environmental parameters across the prehistoric—historic boundary were particularly investigated in an attempt to characterise better the changes associated with the imposition of European land‐use practices. Decreases in arboreal pollen and an increased charcoal concentration near the base of the analysed sequence, interpreted to be about 1600 y BP until about 1300 y BP, are suggestive of reduced moisture availability. After this, a period of relative stability continued to the close of the prehistoric period. The arrival of Europeans in the region triggered changes in the sediment record, including an increase in the accumulation of sediment by an order of magnitude, and changes in the surrounding vegetation. Saturated isothermal remnant magnetism (SIRM) was found to be significantly higher in the historic period compared to the analysed prehistoric period, suggesting an alteration in the erosional processes within the catchment. The concentration of charcoal was comparable between the prehistoric and historic periods; however, the increased sedimentation rate of the historic period infers an increased accumulation of charcoal. Fire did not appear to be related to the vegetation changes evident in the historic period, perhaps due to the use of cool fires by the pastoralists.  相似文献   

金沙江流域水土流失及其防治措施     

邓贤贵 《山地学报》1997,(4)

长江三峡水库入库站寸滩的水沙主要来源于长江上游金沙江和嘉陵江。其中多年平均径流量和输沙量的40.7％和52.7％来自金沙江,这对三峡水利枢纽工程关系重大。该江水土流失十分严重,且有加重趋势,这与人类活动有密切关系,对此提出五项防治措施。  相似文献   

GIS APPLICATION IN RESEARCH OF WILDLIFE HABITAT CHANGE——A case study of the Giant Panda in Wolong Nature Reserve   总被引：2，自引：0，他引：2  

Liu Xuehua Institute of Geography  CAS  Beijing People''s Republic of China M.C. Bronsveld A.G. Toxopeus M.S. Kreijns International Institute for Aerospace Survey  Earth Sciences The Netherlands 《地理学报(英文版)》1997,(4)

Ｉ.ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＧｉａｎｔＰａｎｄａ(Ａｉｌｕｒｏｐｏｄａｍｅｌａｎｏｌｅｕｅａ)ｉｓａｎｅｎｄａｎｇｅｒｅｄａｎｉｍａｌｓｐｅｃｉｅｓｉｎｔｈｅｗｏｒｌｄ.Ｔｈｅｒｅａｒｅａｂｏｕｔ1000ｉｎｄｉｖｉｄｕａｌｓｌｅｆｔａｎｄｃｏｎｆｉｎｅｄｉｎｔｈｅｉｓｏｌａｔｅｄｍｏｕｎｔａｉｎａｒｅａｓｉｎｔｈｅｓｏｕｔｈｗｅｓｔｅｒｎｐａｒｔｏｆＣｈｉｎａ.Ｉｔｓｒｅｍａｉｎｉｎｇｈａｂｉｔａｔｃｏｖｅｒｓａｂｏｕｔ29,500ｋｍ2[2,6,11].Ｈｕｍａｎｅｎｃｒｏａｃｈｍｅｎｔｉｓｃｏｎｓｉｄｅｒｅ…  相似文献   

4,4′-二[(8-羟基喹啉)偶氮]-3,3′-二甲基联苯分光光度法测定锌     

王玉枝  李常青  孙小英  杨桂法 《岩矿测试》1992,(4)

研究了新显色剂4,4,＇-二[(8-羟基喹啉)偶氮]-3.3＇-二甲基联苯(D-HQADMB)与Zn(Ⅱ)的显色反应条件。在CPC存在下的pH7.5～8.5缓冲介质中、Zn(Ⅱ)与D-HQADMB形成稳定的深红色配合物,组成比为Zn(Ⅱ):D-HQADMB=1:2,λ_(max)=550nm,表观摩尔吸光系数为7.19×10~4 L·mol~(-1)·cm~(-1),Zn量在0～1.25μg/ml范围内服从比尔定律。方法可用于测定矿样中的Zn。  相似文献   

人体感热温度与临震前震中区的热异常     

冯贵元 《四川地震》1991,(4):25-29

人体感热温度要受太阳辐射、大气温度、湿度、风等气象要素的影响。临震前,由于影响感热温度的环境状态发生了变化,而使震中区普遍出现热异常。热异常导致了人体感热温度异常,使人们闷热和不适。一定程度的闷热对地震的临震预报有一定的现实意义。  相似文献   

Verteilung ausgewählter toxischer Spurenelemente im Sediment des Breitlingsees bei Brandenburg     

Georg Schettler 《洁净——土壤、空气、水》1992,20(3):142-149

Distribution of Selected Toxic Trace Elements in the Sediment of Lake Breitling near Brandenburg. Considerable enrichments of several heavy metals in relation to the local geological background were found in the surface sediments of Lake Breitling (Havel lake system) (Zn: 50-fold, Cd: 25-fold, Cu: 14-fold, Pb: 13-fold), whereas Be, Co and V are remarkably unchanged if the increased clay mineral content in the more recent sediments is considered. – The heavy metal distribution patterns indicate a high percentage of atmospheric input of these elements, and according to geochemical profiles heavy metal deposition has been constant on a high level for years. – Especially the most enriched Zn which was found to some extent NH₄Ac-exchangeable deserves ecotoxic attention.  相似文献