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911.
采用扫描电子显微镜、电子探针、X射线粉晶衍射、红外光谱、拉曼光谱等测试方法对新疆和田-于田县矿区产出碧玉的结构特征、组成矿物成分进行了测试与分析,得到新疆和田碧玉的典型显微结构为纤维交织结构。组成矿物颗粒呈纤维状、粒状交织排列,进而形成了其手标本细腻的质地与高韧度。和田碧玉为闪石质玉石,主要矿物成分为透闪石,并且含有铬铁矿、绿泥石、蛇纹石、辉石、磷灰石等杂质矿物,透闪石随铁含量的增加向阳起石过渡。  相似文献   
912.
运用DPSIR模型及空间计量方法对黄河流域高质量绿色发展水平及时空演化进行测度和研究。结果表明:(1)黄河流域高质量绿色发展水平呈现稳步提高的趋势,但整体处于初级阶段,1999—2019年年均增长3.32%,内部驱动力和响应方面贡献显著,压力、状态和影响方面发展有待提高。(2)流域内各省区高质量绿色发展水平差异显著,且均呈增长趋势。(3)黄河流域高质量绿色发展水平存在空间自相关,但这一相关性逐渐减弱,并没有形成具有沿黄分布的空间集聚特征。黄河流域高质量绿色发展的空间集聚中心由四川省(1999年)转移到内蒙古自治区(2019年),尚未形成一定规模的空间集聚群。  相似文献   
913.
Masahiko  Yagi 《Island Arc》1993,2(4):240-261
Abstract Alteration of reservoir rocks in the Yurihara Oil and Gas Field, hereafter referred to as the ‘Yurihara field’, have been examined by using samples from six wells. These rocks are basalts in the lowermost part of the basin-fills (‘green tuff’ Formation). These basalts were produced in many eruptions in a submarine environment during the early to middle Miocene, and they underwent continuous intensive alteration genetically associated with Miocene submarine volcanism. The alteration of the basalts is of two types: low grade metamorphism and hydrothermal. The former belongs to the type of ocean floor metamorphism and comprises two subgroups: zeolite (zone I) and prehnite-pumpellyite (zones IIa: vein and amygdule occurrence, and IIb: replacing plagioclase). The latter is characterized by potassic metasomatism accompanied by adularia, quartz and calcite veins (zones IIIa: center and IIIb: margin of the metasomatism). This overprints the low grade metamorphic alteration. The central zone of hydrothermal alteration coincides with a major estimated fault, so that fluids probably assent along the fault. The basalts erupted during 16.5-15.5 Ma, determined by planktonic foraminifera assemblages of inter-bedded shales, then underwent successive low grade metamorphism. In time, the hydrothermal alteration that overprints low grade metamorphism occurred. Adularia veins of the altered rocks located in the hydrothermal alteration zones (zone IIIa and IIIb) have been dated as 9 Ma determined by the K-Ar method. This fact indicates that the activity of low grade metamorphism had already crossed the peak before hydrothermal alteration occurred at 9 Ma. The shape of isotherms of fluid inclusion homogenization temperatures (Th) and that of isolines of apparent salinity (Tm) almost coincide with each other, and these also coincide with the distribution of hydrothermal alteration (zones IIIa and IIIb). This indicates that the fluid inclusions formed at the same time as ascending fluids produced the potassic metasomatism. The maximum Th of the fluid inclusions is 222°C and Tm indicates trapped fluids of up to 3.3 wt% equivalent NaCl (i.e. almost the same as seawater). A Th versus Tm plot indicates mixing occurred between hydrothermal fluids and formation water that has low salinity. Corrensite and chlorite form veins, and the temperatures of their formation, estimated by the extent of aluminium substitution into the tetrahedral site of chlorite, ranges between 165 and 245°C in the centre of the hydrothermal alteration zone (zone IIIa). This is consistent with the result of Th analyses. The deposition temperature of chlorite associated with prehnite in veins ranges between 190 and 215°C in zones IIa and IIb.  相似文献   
914.
The distribution of Al and F contents and the relationship between Al and F in tea plants and soils of 12 tea gardens in Central and Southwest China were investigated from October 31 to November 14, 2006. The results show that there were differences in pH, CEC, the contents of organic matter (OM), Al and F in the different soils of the tea gardens. The Al content ranged from 1196 to 7976mg/kg for old leaf, 370 to 2681mg/kg for young leaf and 285 to 525mg/kg for stem, whereas the content of F ranged from 221 to 1504mg/kg for old leaf, 49 to 602mg/kg for young leaf and 13.5 to 77.5mg/kg for stem. The concentrations of labile Al varied obviously in the different soils, but the distribution law of labile Al content for the same garden was Alexchangeable≈AlFe-Mn oxide>Alorganic>Alwater-soluble. The contents of different labile F fractions varied slightly in the different soils and the different soil layers, though the exchangeable F content was lowest among the labile F in the soils. The concentrations of Al and F in tea plants increased with increasing amount of water-soluble Al or F, especially the amount of water-soluble fractions in the soil layer of 0-20cm.The correlation between Al content and F content in the tea leaf was more significant than that in the tea stem. Furthermore, the correlation between Al content and F content in whole tea plant was strongly significant (r=0.8763, p<0.01, n=36). There were evident tendency that Al concentration increased with the increase of F concentration in different soil layers. The correlation of water-soluble Al with water-soluble F in all soils was also strongly significant (r=0.7029, p<0.01, n=34). The results may provide a proof that Al and F are jointly taken up by tea plants to some extent in natural tea gardens.  相似文献   
915.
黄向京  许桂林  王维 《地震学刊》2010,(3):262-268,286
依托湖南省湘潭至衡阳西线高速公路K 124+300~K 124+895段国内首座加筋格宾组合式挡土墙工程,介绍了以双绞合六边形金属网为筋材的2种新型加筋支挡结构:加筋格宾结构与绿色加筋格宾结构;以极限平衡理论为基础,吸收国外先进加筋土技术,提出了该组合结构的稳定性验算方法与公式;编制相关程序,深入研究了填料粘聚力、内摩擦角、网面拉力、地震力、填土重度、车辆荷载以及加筋间距等重要参数对安全系数的影响。研究表明,各设计参数对安全系数的影响程度不同。同时,也验证了该加筋格宾组合式挡土墙设计的科学性和合理性。研究成果可应用于具体支挡结构设计。  相似文献   
916.
The vegetation growth of the Loess Plateau is often restricted by water, which seriously threatens the water sustainability of regional ecosystem. In order to clarify the relationship between supply and demand of vegetation water use after Grain for Green Project, this study selected Malian River Basin as the research area and calculated the vegetation water use and water demand using the eco-hydrological model. The results showed that the annual water demand of the basin was 570 mm, while the average annual water supply was only 294 mm, accounting only for 52.0% of the demand. From 2000 to 2018, the temporal and spatial matching degree of water supply and demand in the Malian River Basin were 0.63 and 0.65, respectively. On the whole, the water resources in Malian River Basin can basically support the growth of vegetation, but in some areas are not sustainable. Water resources in the southern region can only barely maintain the normal growth of vegetation under the current conditions, so it is not recommended to carry out new plantation in this area. The evaluation of matching degree in the northern from January to April is poor, so it is necessary to appropriately reduce the planting area of economic crops and replace it with planting herbaceous plants with small water consumption in Spring. Compared with the current conditions, under the future climate scenarios of ssp126 and ssp585, the Malian River Basin will show a trend of warming and humidification. The temporal matching degree of water supply and demand also significantly improved to 0.83 and 0.92, indicating that even if the planting structure did not change significantly, water supply would gradually meet the needs of vegetation. The study results can provide the basis for formulating more scientific and reasonable vegetation restoration policies.  相似文献   
917.
Urban Green Spaces (UGS) offer social and environmental benefits that enhance quality of life of the residents. However, due to the underlying social and economic disparities, different sections of urban population have disproportionate level of access to UGS. The environmental inequity owing to the varied UGS distribution poses a challenge to urban planners in efficient resource allocation. This study attempts to counter this challenge using a novel remote sensing-based approach. The variations in UGS distribution (in terms of quantity, quality and accessibility) across the neighbourhoods in Mumbai vis-à-vis the socio-economic status (SES) of neighbourhood residents are assessed using remote sensing-based indicators. Further, as these indicators are susceptible to the effect of changing scales, a multi-scale approach is adopted to study the potential variations in the relationship between SES and spatial metrics of UGS with spatial resolution. The neighbourhood SES was assessed using the newly developed Socio-Economic Status Index (SESI) and the neighbourhoods were classified into multiple SES categories. The UGS were extracted from remotely sensed data using Normalized Difference Vegetation Index (NDVI), and their spatial distribution aspects were characterized using indicators at neighbourhood level. The variations in indicators of UGS distribution in the neighbourhoods belonging to different SES categories were analysed using a logistic regression model. The results showed that, while quantity of UGS is not statistically associated with neighbourhoods SES, the quality and accessibility aspects of UGS share a statistically significant relation with SES. Also, this relation was found to vary significantly with spatial resolutions. Further, it was found that the neighbourhoods with higher SES in Mumbai have a better access to green spaces, indicating spatial inequities in UGS distribution in Mumbai. This study has important implications for planning equitable green spaces in cities that are currently in urbanization transition.  相似文献   
918.
Combining some information from field investigation of algae along the coastal areas in China and a few pictures materialized from the western Yellow Sea in 2008,authors analyze the necessary conditions and possible water area in China producing a large biomass,some reasons for firestorm,and the possibility of the reappearance of marine bloom green alga Enteromorpha prolifera.The change of habitats and the increase of nutritional levels related to the water area could be considered as direct reasons.It was ...  相似文献   
919.
李端生 《吉林地质》2002,21(4):81-88
矿化程度极低的深层地下水,往往给人体健康带来各种危害,主要是欠缺某些化学元素引起的地方病,过去多被忽视。以为矿化程度越低水质越佳;饮用水标准中各种化学元素规定的下限值常不被重视,一旦发生了疾病,多从污染或元素超标中查找问题。由于这种认识偏差,常常造成防治不利,贻误战机。松嫩平原部分氟病区,因为饮了深层“超低氟水”(水中氟的质量分数小于0.2mg/L)新发了大骨节病或患了无名疼痛病,即为典型例证。防治办法,一要加强源头矿化,二要注意终端补氟。由此有“药疗不如食疗”、“饮疗胜于食疗”之说,饮茶是最佳补氟之举,而且要从孕期或婴幼儿做起。拟彻底根治,可深浅层地下水混合开采。  相似文献   
920.
Large urban areas are typically characterized by a mosaic of different land uses, with contrasting mixes of impermeable and permeable surfaces that alter “green” and “blue” water flux partitioning. Understanding water partitioning in such heterogeneous environments is challenging but crucial for maintaining a sustainable water management during future challenges of increasing urbanization and climate warming. Stable isotopes in water have outstanding potential to trace the partitioning of rainfall along different flow paths and identify surface water sources. While isotope studies are an established method in many experimental catchments, surprisingly few studies have been conducted in urban environments. Here, we performed synoptic sampling of isotopes in precipitation, surface water and groundwater across the complex city landscape of Berlin, Germany, for a large -scale overview of the spatio-temporal dynamics of urban water cycling. By integrating stable isotopes of water with other hydrogeochemical tracers we were able to identify contributions of groundwater, surface runoff during storm events and effluent discharge on streams with variable degrees of urbanization. We could also assess the influence of summer evaporation on the larger Spree and Havel rivers and local wetlands during the exceptionally warm and dry summers of 2018 and 2019. Our results demonstrate that using stable isotopes and hydrogeochemical data in urban areas has great potential to improve our understanding of water partitioning in complex, anthropogenically-affected landscapes. This can help to address research priorities needed to tackle future challenges in cities, including the deterioration of water quality and increasing water scarcity driven by climate warming, by improving the understanding of time-variant rainfall-runoff behaviour of urban streams, incorporating field data into ecohydrological models, and better quantifying urban evapotranspiration and groundwater recharge.  相似文献   
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