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101.
空间数据的拓扑关系及其自动生成 总被引:8,自引:0,他引:8
本文讨论了空间数据的拓扑关系,对地图的基本图形元素作了更准确的表述;详细介绍和讨论了自动生成空间数据拓扑关系的原理和方法,重点研究和探讨了并列和嵌套的面域拓扑关系。本文所述的方法适用于多种复杂的空间实体关系。 相似文献
102.
To investigate the solubility and the sites of incorporation of hydrogen in olivine as a function of point defect concentration, two-stage high-temperature annealing experiments have been carried out. The first annealing stage (the dry preannealing stage) was conducted at a total pressure of 0.1 MPa, a temperature of 1300° C and various oxygen fugacities in the range 10?11–10?4 MPa for times > 12 h. In these heat treatments, the samples were buffered against either orthopyroxene or magnesiowustite, or they remained unbuffered. The second annealing stage (the hydrothermal annealing stage) was performed at 300 MPa and 900–1050 ° C under a hydrogen fugacity of ~ 158 MPa for 1–5 h. Infrared spectra from the annealed samples revealed two distinct groups of bands. Group I bands occurred at wavenumbers in the range 3450–3650 cm?1, while Group II bands occurred in the range 3200–3450 cm?1. The hydrogen solubility associated with Group I bands is proportional to f O 2 to the 1/6 power for samples preannealed in contact with orthopyroxene, to the 1/3 power for samples preannealed in contact with magnesiowustite, and to the 1/13 power for samples preannealed in the absence of a solid-state buffer. The hydrogen concentration for Group II bands varies with f o 2 to the 1/3 power for opxbuffered samples, to the 1/2 power for mw-buffered samples, and to the 1/3 power for unbuffered samples. The dependence of hydrogen solubility on oxygen fugacity and orthopyroxene activity suggests that hydrogen is incorporated into the olivine structure via association with point defects. The presence of two distinct groups of absorption bands indicates that hydrogen is associated with two distinct lattice defects. The following point defect model for the mechanism of incorporation of hydrogen in olivine is consistent with these results: Hydrogen ions responsible for the Group I bands are associated with doubly charged oxygen interstitials, while hydrogen ions responsible for the Group II bands are associated with singly charged oxygen interstitials. Furthermore, the infrared bands observed in naturally derived olivines are present in spectra from our hydrothermally annealed crystals. Thus, the mechanisms of incorporation of hydrogen in olivine under geological conditions are the same as those operative under laboratory conditions. The maximum solubility reached in these experiments was ~ 360H/106Si, which corresponds to ~ 0.002 wt% of H2O. This value is a lower bound for the solubility of hydrogen in olivine under upper mantle conditions. 相似文献
103.
从信息论原理和分形几何学的观点出发,采用多种方法,分析研究1988年澜沧—耿马7.6级地震前地震活动的信息、信息熵和分维的变化特征表明,地震前1—2年内,中、小地震活动的信息熵、缺信量和容量维、信息维出现明显的低值变化过程,反映了地震前兆的减熵、降维特点,从一个侧面反映了大震前,一定区域内中、小地震活动的时空变化从无序向有序的演化过程。 相似文献
104.
105.
106.
托里活断层、达尔布特活断层、独山子—安集海活断层及霍尔果斯—卡子湾活断层是塔城地区主要的全新世活断层,均有过多次古地震活动。自1977年以来,4级以上地震活动的空区在裕民县西北。据活断层古地震活动复现期及地震活动围空特点分析,今后10年北天山或塔城西北可能有发生6级左右地震的危险。 相似文献
107.
起伏加剧是相态突变前的一种临界现象,本文应用这一观点探讨了强地震前小震活动频次和地下流体、气体、地应力等前兆变化的起伏加剧现象,并得到以下初步结果: 1.临近强地震前较大范围内超过平均日活动水平的小震活动的空间分布具有有序性,即出现穿过未来大震区的小地震活动条带,条带的交汇区为未来大震区。2.强地震前的小震高频次活动日大多与外因出现时间同步,目前发现的外因有塑望、节气、中强以上磁暴以及大气压力下降等。这种小震的高频次活动一般出现在震前当天至一个月时间内。3.前兆的起伏时间和小震频次的起伏时间大致同步。它们在成因上有联系。 相似文献
108.
Reported in this paper are K-Ar ages of volcanic rocks, biotite-granite and greisen from the Lianhuashan tungsten mine in Guangdong Province. The isotopic dilution method was adopted in this work. Whole-rock isochron ages of the volcanic rocks are in the range 120.4±12.1 m.y. The petrogenetic age of biotite-granite and the minero genetic age of tungsten ore are close to those of the volcanic rocks. The apparent ages of various types of rock in the mining district generally bias towards younger values, which may be attributed to the effects of late thermal events which took place in the circum-Pacific metallogenetic belt. 相似文献
109.
110.
On the basis of its geological characteristics, the Gushan iron deposit should be assigned to volcano-hydrothermal type with hematite-quartz as its principal mineral assemblage. Iron concentration of the ore solution has been estimated from the ratio of hematite to quartz in the ore. By using experimental and thermodynamic data, the solubility of ferro-minerals at elevated temperatures and pressures have been calculated in the system FeO?Fe2O3?NaCl?HCl?H2O. The effects ofT, P, pH,f O 2 and total Cl concentration on the solubility of ferrominerals are discussed. Thermodynamic calculations based on presumed physico-chemical conditions for the ore solution are in good agreement with geological observations. The calculation shows that ferro-minerals were deposited at logf O 2=?21~?25, log(mHCl+mH+)=?2.5~?3,P=1?0.75 (or 0.5) kb, andT=400°?350°C. It is believed that the original solution was an acid NaCl-bearing solution of magmatic derivation. However, iron in the solution was enriched with falling temperatures by dissolving pre-existing ferro-minerals in consolidated rocks rather than extracting directly from the magma. Either temperature (below 400°C) or pressure decrease may result in the precipitation of ferro-minerals from the solution, but the Fe/Si ratio in the ore is dependent mainly upon pH. The widespread siliceous veins of later stages are a reflection of decreasing acidity of the solution. An increase inf O 2 will also favor the deposition of ferro-minerals. The hypabyssal occurrence and the existence of the Huangmaqing sandy shale have contributed greatly to the formation of hematite. 相似文献