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121.
为探讨高原牌70kN和进口120,210kN瓷绝缘子的成分和结构性能,中采用原子吸收光谱(AAS)和X射线衍射(XRD)方法,对三类产品进行了检测。结果表明,有效成分除K2O外,70kN和210kN的SiO2,Al2O3,Fe2O3含量接近,主晶相基本相同,有刚玉,莫来石、石英和长石等;结晶相总量:70kN35%,120kN40%,210kN48%,这表明机械强度愈大,结晶相含量愈高,只需调整70kN原样的部分成分,粒度和工艺,即生产出高等级(如210kN)瓷绝缘子。 相似文献
122.
The Upper Cretaceous Juniper Ridge Conglomerate (JRC) near Coalinga, California, provides a rare, high-quality exposure of a submarine channel to overbank transition. The facies architecture of the JRC comprises a thick, predominantly mudstone sequence overlain by a channellized conglomerate package. Conglomeratic bounding surfaces truncate successions of interbedded turbiditic sandstones and mudstones both vertically and laterally. Thick-bedded, massive sandstones are interbedded with conglomerates. Facies architecture, palaeocurrent indicators, slump features, sandstone percentages and sandstone bed thickness trends lead to the interpretation that these elements comprise channel and overbank facies. A vertical sequence with conglomerate at the base, followed by thick-bedded sandstone, and capped by interbedded turbiditic sandstone and mudstone form a fining-upward lithofacies association that is interpreted as a single channel-fill/overbank system. Three similar lithofacies associations can be related to autocyclic processes of thalweg migration and submarine fan aggradation or to allocyclically driven changes in sediment calibre. 相似文献
123.
Abstract. Several epithermal gold deposits occur in the Hoshino area, which is located in the western end of the late Cenozoic Hohi volcanic zone, north‐central Kyushu, Japan. The area is characterized by intermediate to felsic extrusive rocks of Pliocene age. In the Hoshino area, the shallow manifestation of the hydrothermal activity is exposed on the surface. Several outcrops of sinter are still preserved on the top of hydro thermally altered volcanic rocks, and high‐grade gold‐bearing quartz veins occur on the surface at lower levels. The hydrothermal alteration resulted into well‐developed alteration zones. The zonal alteration pattern, primarily of near‐neutral pH type, is characterized by the outer smectite zone of a lower temperature, and the inner mixed layer minerals zone of a higher temperature. Quartz vein‐related or fracture‐controlled alteration, is represented by the occurrence of interstratified illite/smectite and K‐feldspar, suggesting a potassium‐enriched alteration. The mineralization in the Hoshino area is recognized on the surface by the occurrence of gold‐bearing quartz veins distributed mainly in the mixed layer minerals zone. The fracture system related to the gold mineralization is mainly characterized by NW‐SE trend. The alteration pattern and the mineralogical composition of the veins suggest that the mineralizing fluids had near‐neutral pH and the mineralization is of low‐sulfidation‐type. Fluid inclusion data and textures observed in quartz veins indicate that gold precipitated during boiling. The chemical composition of quartz veins shows that high‐grade gold‐bearing quartz veins are characterized by higher content of Al2O3, K2O and Rb. Several outcrops of silica‐sinters are distributed on the top of the mixed layer minerals zone. Although their structures are not very well preserved, because of later silicification, the Hoshino sinters still show characteristic textures identical to those observed in modern sinters, such as the presence of plant fossil incorporated into the sinters, the strongly developed depositional laminations and the columnar structures perpendicular to the depositional surfaces. Quartz is the only silica mineral constituting the Hoshino sinters presently. The conversion of amorphous silica into quartz was probably governed by higher temperatures resulting from later hydrothermal activity. This later hydrothermal activity is reflected by the intense silicification affecting mainly the lower parts of the sinters and also by the presence of quartz veins cutting the sinters. The distribution of sinters in the Hoshino area is very significant. The presence beneath the sinters of concealed high‐grade gold‐bearing quartz veins should be highly considered and exploration work is strongly suggested. 相似文献
124.
Thermal waters hosted by Menderes metamorphic rocks emerge along fault lineaments in the Simav geothermal area. Thermal springs and drilled wells are located in the Eynal, Çitgöl and Na
a locations, which are part of the Simav geothermal field. Studies were carried out to obtain the main chemical and physical characteristics of thermal waters. These waters are used for heating of residences and greenhouses and for balneological purposes. Bottom temperatures of the drilled wells reach 163°C with total dissolved solids around 2225 mg/kg. Surface temperatures of thermal springs vary between 51°C and 90°C. All the thermal waters belong to Na–HCO3–SO4 facies. The cold groundwaters are Ca–Mg–HCO3 type. Dissolution of host rock and ion-exchange reactions in the reservoir of the geothermal system shift the Ca–Mg–HCO3 type cold groundwaters to the Na–HCO3–SO4 type thermal waters. Thermal waters are oversaturated at discharge temperatures for aragonite, calcite, quartz, chalcedony, magnesite and dolomite minerals giving rise to a carbonate-rich scale. Gypsum and anhydrite minerals are undersaturated with all of the thermal waters. Boiling during ascent of the thermal fluids produces steam and liquid waters resulting in an increase of the concentrations of the constituents in discharge waters. Steam fraction, y, of the thermal waters of which temperatures are above 100°C is between 0.075 and 0.119. Reservoir pH is much lower than pH measured in the liquid phase separated at atmospheric conditions, since the latter experienced heavy loss of acid gases, mainly CO2. Assessment of the various empirical chemical geothermometers and geochemical modelling suggest that reservoir temperatures vary between 175°C and 200°C. 相似文献
125.
Determining gaseous composition of fluid inclusions with quadrupole mass spectrometer 总被引:3,自引:0,他引:3
Quadrupole mass spectrometer (QMS) is an instrument for effectively determining gaseous composition of fluid inclusion. The
gaseous component is extracted from inclusions with thermal decrepitation method and then determined with the sensitive QMS
instrument. The method is characterized by high sensitivity and high accuracy with the relative standard deviation (RSD,n=6) of less than 3%. It has been successfully used for analyzing fluid inclusions. The analytical results meet the requirement
of geological study. 相似文献
126.
长江巨洪前期物理因子的配置 总被引:4,自引:4,他引:4
提出了长江巨洪前期物理因子配置的概念,在每一次巨洪发生之前,影响巨洪的主要物理因子之间一般都会表现出相似的特征,即出现一些固有的配置,这些配置正是长江发生巨洪的强信号,对长江巨洪的预测研究具有重要的指示作用。 相似文献
127.
Florence Sylvestre 《Journal of Paleolimnology》2002,27(1):45-57
A diatom study of lacustrine sediments in the southern part of the Bolivian Altiplano (Salar of Coipasa) provides a continuous record of the period 21,000–17,500 14C yr BP. Constrained by seven AMS 14C dates, this record provides evidence that the Coipasa basin was filled by a shallow body of water during this time. Diatom/salinity and diatom/ionic composition transfer functions indicate that the lake was saline, dominated by sodium-chloride throughout all the period.A comparison with regional data shows that Lake Titicaca could not have overflowed towards the southern Bolivian Altiplano at that time. As this dry phase was not registered in Lake Coipasa, this lake was probably supplied by winter precipitation originating from the Pacific. But, recent data from the deep basin of Lake Titicaca show that the lake-level was higher during this time interval, and the question arises whether precipitation from Atlantic and Amazonia sources could have played an important role on the Altiplano during the Last Glacial Maximum (LGM). This hypothesis needs to match other available paleoclimatic data from the lowlands of tropical South America, where there is evidence that during the LGM, conditions were drier than today. Global climate simulations suggest a positive P-E on the Altiplano, due to a strong cooling, reducing evaporative demand more than any increase in precipitations. An increase of winter precipitation from the Pacific is in agreement with data from the Chilean coast showing a northward locations of the Westerlies during the LGM. This paleoclimatic hypothesis is also in agreement with a coupled ocean-atmosphere model, which indicates weaker summer precipitation and stronger winter precipitation in the tropical areas. 相似文献
128.
Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental
water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater’s
economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da’an
in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All
water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation
scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic,
ecologic and social benefits were obtained. 相似文献
129.
130.
On the spatial relationship between landslides and causative factors on Lantau Island, Hong Kong 总被引:8,自引:0,他引:8
This paper presents a statistical approach to study the spatial relationship between landslides and their causative factors at the regional level. The approach is based on digital databases, and incorporates such methods as statistics, spatial pattern analysis, and interactive mapping. Firstly, the authors propose an object-oriented conceptual model for describing a landslide event, and a combined database of landslides and environmental factors is constructed by integrating the various databases within such a conceptual framework. The statistical histogram, spatial overlay, and dynamic mapping methods are linked together to interactively evaluate the spatial pattern of the relationship between landslides and their causative factors. A case study of an extreme event in 1993 on Lantau Island indicates that rainfall intensity and the migration of the center of the rainstorm greatly influence the occurrence of landslides on Lantau Island. A regional difference in the relationship between landslides and topography is identified. Most of the landslides in the middle and western parts of the island occurred on slopes with slope angles of 25–35°, while in the eastern part, the corresponding range is 30–35°. Overlaying landslide data with land cover reveals that a large number of landslides occurred in the bareland and shrub-covered area, and in the transition zones between different vegetation types. The proposed approach can be used not only to analyze the general characteristics of such a relationship, but also to depict its spatial distribution and variation, thereby providing a sound basis for regional landslide prediction. 相似文献