首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The results of REE leached by some organic acids with various concentrations and water/rock ratios for different durations from a mixed samples of the weathering crust of a granite in Gonghe,Guangdong,China,showed that:1)the contents of REE leached increase with increasing concentrations of the organic acids;2) the contents of REE leached by 0.01mol/L organic acids increase with increasing water/rock ration;3) the interaction between the organic acids and the samples enhances the pH value of the medium and the contents of REE leached tend to increase with decreasing pH value;and 4) compared with those leached by ammonia sulfate,the REE leached by the organic acids are characterized by a weaker negative C e anomaly,a stronger negative Eu anomaly,and lower(La/Sm)N and (Gd/Yb)N ratios,indicating that the organic acids have made contributions to the fractionation of REE in the weathering crust.  相似文献   

2.
Acta Geologica Sinica (formerly the Bulletin of the Geological Society of China) beganpublication in 1922, and was published mainly in English through 1952. Since then, thejournal has been published in Chinese with English abstracts. In March 1988, ActaGeologica Sinica appeared in English language translation. The journal is a full translationof the Chinese edition, and follows the Chinese edition by two issues.  相似文献   

3.
Acta Geologica Sinica (formerly the Bulletin of the Geological Society of China) beganpublication in 1922, and was published mainly in English through 1952. Since then, thejournal has been published in Chinese with English abstracts. In March 1988, Acta  相似文献   

4.
Acta Geologica Sinica(formerly the Bulletin of the Geological Society of China) began publication in 1922, and was published mainly in English through 1952. Since then, the journal has been published in Chinese with English abstracts. In March 1988, Acta Geologica Sinica appeared in English language translation. The journal is a full translation  相似文献   

5.
Livestock wastes applied to agricultural land are potential sources of steroidal hormones (estradiol (E2), estrone (E1), and estriol (E3)) that can adversely affect the aquatic ecosystem as endocrine disruptors. But the effects of plants on the fate of estrogen in the environment are not clearly known. In the present report, the behavior of E1, E2 and E3 added to the rhizospheric soil in various concentrations and its effect on plant growth were examined by estrogen batch sorption test, plant pot test and estrogen extraction test. Trifolium repens was grown on the soil spiked with E2 or a mixture of E1, E2 and E3. Pots without plant were prepared as controls. All pots were watered in 50 ml dose almost every day, and the rhizosheric soil and plant body were collected 7, 19, 26, 33 days after planting. The soil was sequentially extracted with Milli-Q water, and methanol / 1M acetic acid solvent followed by methanol wash at the solid to liquid ratio of 1 : 4 (g/mL). Extracts were analyzed for El, E2 and E3 using a Shimadzu GCMS-QP5050. Plant dry weight (4 hours, 105 ℃) was measured as an indicator of plant growth. In batch sorption tests, E1 and E2 concentrations in the liquid phase significantly decreased within 24 hours after the addition of estrogen. The sum of methanol / 1M acetic acid extractable E 1 and E2 in the soil decreased to half of the initial added amount within 7 days. Reduction in total estrogenic activity of the soil extracts (estimated as 0.01CE1+CE2+0.1CE3 where CE1, CE2 and CE3 are respective El, E2 and E3 concentrations per unit soil weight) continued for 1 month due to slow oxidation of E2 to E1. Desorption of E2 from soil during the pot experiment was higher than expected from the sorption experiment.  相似文献   

6.
Discussion on the Transform of Paleotethys into the Pacific   总被引:1,自引:0,他引:1  
1.IntroductionTherehavebeenalargeamountofresearchesontheN--SextendingPaleotethysinthePaleozoicandonthemodernE--WextendingPacificOceanintheCenozoic.ButfewhavetouchedonhowthePaleotethysevolvedintothemodemPacific,andthereareonlyguessesaboutthesitllationofthePaleo--Pacificbetweenthetwostages.ThispapertriestodiscussthedynamicmechanismofthePaleo--PacificplateandthecharacteristicsoftheactivitiesofEastAsiacontinentalmarginintheMesozoicthroughtheterranesfromPaleotethysremainingintheEastAsiacont…  相似文献   

7.
Plastic mulching is widely used for the vegetables growing all over the world. However, plastic mulching might change the soil physic-chemical properties due to its mini-greenhouse effect. The purpose of this study is to probe the possible transportation …  相似文献   

8.
The geological structure of monzodiorite—granite massifs (Stepninskii, Biryukovskii, Vandyshevskii, and Uiskii) of the Stepninskii complex extending as a chain of intrusive bodies crossing the submeridional structures of the Ural Fold Belt is described. These granite massifs are ascribed to the Permian and, as suggested, are related to a mantle plume. Based on the results of studying melt and gas—liquid inclusions in quartz from granitoids, it was established that the rock crystallization depth in the given series of massifs decreases gradually in the northwesterly direction from hypabyssal to hypabyssal—subsurface facies. It is shown that leucocratic and aplitic varieties of granites with a higher level of fluid content have rare-metal metallogenic specificity and are promising in the search for W—Mo ore mineralization.  相似文献   

9.
There is a massive amount of geomorphic evidence for active tectonics in the Longmen Shan at the eastern margin of the Tibetan plateau. We have surveyed some typical geomorphic markers including the Wenchuan-Maowen, Beichuan-Yingxiu and Pengxian-Guanxian faults, terrace offsets, scarps, fault-controlled saddles, dextral shutter ridges, dextral channel offsets, graben, shatter belts, and pull-apart basins. Electron spin resonance (ESR) and thermoluminescence(TL) ages were obtained using silty sand taken from below the surface of the sediments. According to these data, we calculated the rates of thrusting and strike-slip, and the results indicate that Cenozoic tectonic shortening at the plateau margin is minor with the rate of thrusting less than 1.10 mm/a and the rate of strike-slipping less than 1.46 mm/a. The Longmen Shan is a zone of NNE-trending dextral shear with slip-dip ratio of 6:1-1.3:1. From NW to SE, the thrust component becomes smaller, whereas the strike-slip component becomes larger.  相似文献   

10.
Doklady Earth Sciences - The influence of the temperature and moisture content of the near-surface soil layer on variations of the barodeformation interaction of the boundary layer of the...  相似文献   

11.
The Taipinghu Bridge is an important project, and the safety of rock masses of its foundation is very crucial. This article analyzes the potential causes of the deformation of the rock masses of the bridge foundation, and uses the Fast Lagrangian Analysis of Continua to analyze the geologic model. The simulating process shows that no mater in the excavating process or in the loading process the rock masses are suit for the engineering. The modeling and analyzing process can be used for reference.  相似文献   

12.
Doklady Earth Sciences - A method for estimating the contribution of atmospheric pressure variations to the deformation of the upper layer of the Earth’s crust using synchronous data from...  相似文献   

13.
The Taipinghu Bridge is an important engineering construction, and the safety of rock mass of its foundation is very crucial. This article adopts FLAC 3D to analysis the geologic model. The simulating process shows that no mater the excavating process or the loading process the rock mass are safe. The modeling and analyzing process can be used for reference.  相似文献   

14.
As viewed from space remote-sensing images (e.g. Google Earth images) of South Guizhou and North Guangxi, the authors found that macroscopic karst landscape on the Earth’s surface is strongly controlled by the Conjugated shear joint of “X” type. Joints of this kind constitute a huge infiltration network and act as channel-ways for the permeation of meteoric waters from the surface, thus, leading to the dissolution of carbonate rocks nearby. As a result, the karst landscape is formed, which is dominated by linear karst valleys. An “X” karst valley network structure appears in the area where horizontal strata are distributed, and a feather-like network structure appears in the area where vertical strata are distributed, respectively. When the water permeates downwards to the underground-water level, it will flow horizontally along the strike of “X” joints toward the local base level of erosion to form an “X” network system of underground conduits in the area where horizontal strata are distributed, but it is relatively complex, because of the joining of other joints. This is the first time we have made use of Google Earth images to study the karst environment. Therefore, it has been successful in research on the Earth’s geomorphology, which could only rely on aerial photos and satellite photos in the past. Google Earth images provide low-cost and applicable imaging materials for the study of Earth’s geomorphology and karst rocky desertification and its control.  相似文献   

15.
The sorption of aqueous cadmium on carbonate-hydroxyapatite (CHap) is a complicated non-homogeneous solid/water reaction, From kinetic point of view, it can be described by two stages: at the earlier stage, reaction rate is so fast that its kinetic course is intricate, and at the later stage, the rate of reaction becomes slow and the process of reaction accords with one order reaction kinetic equation. Experimental results show that the relationship between reaction rate constant kl and temperature T accords to Arrhenius Equation, and the activation energy of sorption (Ea) is 6.075 J/mol and frequency factor (A) is 220 s^-1. At the same time, reaction rate constant kl increases with decreasing Cd^2+ initial concentration, on the contrary, with increasing pH and CHap dosage.  相似文献   

16.
The Taipinghu Bridge is an important engineering construction,and the safety of rock mass of its foundation is very crucial.This article adopts FLAC3D to analysis the geologic model.The simulating process shows that no mater the excavating process or the loading process the rock mass are safe.The modeling and analyzing process can be used for reference.  相似文献   

17.
Contamination sites pose significant environmental hazards to terrestrial ecosystems. Evaluation of the effects of contaminants in soils has become a priority for OECD countries. The biomarker approach is widely used both in vertebrates and in invertebrates for environmental biomonitoring. Eisenia fetida would provide diagnostic and prognostic early warning tests for monitoring soil contamination. These responses, often called early warning signals, would, in fact, give very important information when assessing the environmental risks of contamination. However, the use of biomarkers requires the identification of every possible variation that can influence the biochemical response, because ecosystems are generally subject to a mixture of pollutants,  相似文献   

18.
19.
20.
Tobacco is an important cash crop in Pakistan. It is a sensitive plant prone to many bacterial, fungal, and viral diseases. It is also attacked by several species of worms, beetles and moths. Therefore high levels of pesticides are used to grow tobacco. The obvious benefits from the use of the pesticides are so spectacular that some of the problems associated with their use are not recognized. However, many of these pesticides are highly toxic and have impacts on tobacco workers, especially occupational exposures, which are the direct victims of pesticides poisoning. The victims include many children, pregnant women and elders who all participate in tobacco production. Pesticides either cause or exacerbate a number of illnesses in farmers and farm workers when they are exposed to them. So, occupational exposure is probably one of the most important impacts on tobacco farmers, since they and their families are exposed constantly to a large amount of pesticides. This exposure can lead to many serious problems. No study has been done to identify the effects of tobacco pesticides on human health especially on farmers health in Pakistan. The objective of this paper is to establish a correlation of pesticides application on tobacco crop with cancer incidence in the tobacco growing districts of NWFP- Pakistan.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号