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11.
Interatomic potential parameters have been derived at simulated temperatures of 0 K and 300 K to model pyrite FeS2. The predicted pyrite structures are within 1% of those determined experimentally, while the calculated bulk modulus is within 7%. The model is also able to simulate the properties of marcasite, even though no data for this phase were included in the fitting procedure. There is almost no difference in results obtained for pyrite using the two potential sets; however, when used to model FeS2 marcasite, the potential fitted at 0 K performs better. The potentials have also been used to study the high-pressure behaviour of pyrite up to 44 GPa. The calculated equation of state gives good agreement with experiment and shows that the Fe–S bonds shorten more rapidly that the S–S dimer bonds. The behaviour of marcasite at high pressure is found to be similar to that of pyrite. 相似文献
12.
XU Guobin Senior Research Engineer Tianjin Institute of Hydroelectric Investigation Design Research Ministry of Water Resources. Dongting Road Hexi District Tianjin P R. China. BAI Shilu Senior Research Engineer Tianjin Institute o 《国际泥沙研究》1997,(3)
I.INTRODUCTIONReseri,oirsonoverloadedriverswillreachthestateofrelativeequilibriumwithcontinuousdevelopmentofsedimentation.Insuchcase,thereisdePOsitinfrontofthedam.Thereforethesiltpressureonthedambodyisconsiderablylarge.Sedimentationelevationinfrontofthedamisoneofthefactorsofcalculatingthesiltpressure.Inaddition,tokeeplong-termworkingstorageinreservoif,itisnecessarytoinstallbottomoutlets.Asthereisapressureconduitinfrontoftheoperatinggateofthebottomoutlet,thesedimelltenteredtheconduitwill… 相似文献
13.
Kela 2 Gas Field, with high formation pressure (74.35MPa), high pressure coefficient (2.022) and difficulty of potential test and evaluation, is the largest integrated proved dry gas reservoir in China so far and the principal source for West-East Gas Development Project. In order to correctly evaluate the elastic-plastic deformation of rocks caused by the pressure decline during production, some researches, as the experiment on reservoir sensitivity to stress of gas filed with abnormal high pressure, are made. By testing the rock mechanic properties, porosities and permeabilities at different temperature and pressure of 342 core samples from 5 wells in this area, the variations of petro-physical properties at changing pressure are analyzed, and the applicable inspection relationship is concluded. The average productivity curve with the reservoir sensitivity to stress is plotted on the basis of the research, integrated with the field-wide productivity equation. The knowledge lays a foundation for the gas well productivity evaluation in the field and the gas field development plan, and provides effective techniques and measures for basic research on the development of similar gas fields. 相似文献
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波浪作用下黄河口粉土液化与“铁板砂”形成机制的模拟试验研究 总被引:2,自引:0,他引:2
通过室内水槽试验,观测波浪作用下土体产生的振荡现象,分析土体内孔隙水压力的变化及波浪作用后土体强度变化特征,研究了波浪荷载作用下黄河口粉土粒径粗化和“铁板砂”的形成过程。试验及讨论结果表明:在波浪作用下上层粉土体大部分时间处于液化状态;由液化土形成的振荡土层与下部土层之间形成“W”型的滑动面,振荡土层的厚度随着波浪作用时间的增加而变小;细粒物质从振荡土层中的骨架中脱离进入水体中,并在土体表层形成一层以黏粒为主的絮凝状沉积物,其厚度随波浪作用时间的增加而增加,在土体停止振荡前达到最大值;土体液化是“铁板砂”形成的必要条件,而波浪引起的液化土体振荡则使“铁板砂”的形成成为可能。 相似文献
16.
Lin-gun Liu C.-C. Lin Y. J. Yung T. P. Mernagh T. Irifune 《Physics and Chemistry of Minerals》2009,36(3):143-149
K-lingunite is a high-pressure modification of K-feldspar that possesses the tetragonal hollandite structure. Variations of
the Raman spectra of K-lingunite were studied up to ~31.5 GPa at room temperature, and in the range 79–823 K at atmospheric
pressure. The Raman frequencies of all bands were observed to increase with increasing pressure, and decrease with increasing
temperature for K-lingunite. This behavior is in line with those observed for most of other materials. New sharp Raman bands
appear at pressures greater than 13–15 GPa, suggesting a phase transition in K-lingunite with increasing pressure. The transition
is reversible when pressure was released. The appearance of these new Raman bands may correspond to the phase transition revealed
earlier at around 20 GPa by X-ray diffraction studies. Instead of transforming back to its stable minerals, such as orthoclase,
microcline or sanidine, K-lingunite became amorphous in the temperature range 803–823 K at atmospheric pressure. 相似文献
17.
Metamorphic evolution of garnet-bearing ultramafic rocks from the Gongen area, Sanbagawa belt, Japan 总被引:2,自引:0,他引:2
Garnet‐bearing ultramafic rocks including clinopyroxenite, wehrlite and websterite locally crop out in the Higashi‐akaishi peridotite of the Besshi region in the Cretaceous Sanbagawa metamorphic belt. These rock types occur within dunite as lenses, boudins or layers with a thickness ranging from a few centimetres to 1 metre. The wide and systematic variation of bulk‐rock composition and the overall layered structure imply that the ultramafic complex originated as a cumulate sequence. Garnet and other major silicates contain rare inclusions of edenitic amphibole, chlorite and magnetite, implying equilibrium at relatively low P–T conditions during prograde metamorphism. Orthopyroxene coexisting with garnet shows bell‐shaped Al zoning with a continuous decrease of Al from the core towards the rim, consistent with rims recording peak metamorphic conditions. Estimated P–T conditions using core and rim compositions of orthopyroxene are 1.5–2.4 GPa/700–800 °C and 2.9–3.8 GPa/700–810 °C, respectively, implying a high P/T gradient (> 3.1 GPa/100 °C) during prograde metamorphism. The presence of relatively low P–T conditions at an early stage of metamorphism and the steep P/T gradient together trace a concave upwards P–T path that shows increasing P/T with higher T, similar to P–T paths reported from other UHP metamorphic terranes. These results suggest either (1) down dragging of hydrated mantle cumulate parallel to the slab–wedge interface in the subduction zone by mechanical coupling with the subducting slab or (2) ocean floor metamorphism and/or serpentinization at early stage of subduction of oceanic lithosphere and ensuing HP–UHP prograde metamorphism. 相似文献
18.
The pressure dependence of the zirconium-in-rutile thermometer 总被引:19,自引:1,他引:19
The solubility of ZrO2 in rutile is strongly temperature-dependent and has been identified as a potentially powerful thermometer when the rutile coexists with an appropriate buffer assemblage, e.g. zircon + quartz. In combination with experimental data at 10 kbar, previous consideration of data on natural rutile has not identified a pressure dependence for the thermometer. However, the expected volume change as a result of substitution of the larger Zr4+ cation for Ti4+ suggests that the Zr content of rutile should decrease with increasing pressure. To investigate the pressure dependence of the thermometer, piston cylinder (at 10, 20 & 30 kbar) and 1 atm furnace experiments were performed in the system ZrO2 -TiO2 -SiO2 . The solubility of ZrO2 in rutile, in the presence of zircon and quartz was reversed at each pressure value. From these experiments, the thermodynamics of the end-member reaction ZrSiO4 = SiO2 + ZrO2 (in rutile) have been determined. There is a secondary pressure effect accompanying the primary temperature dependence of the Zr content of rutile. New thermometer equations are, in the α -quartz field: in the β -quartz field and in the coesite field in which φ is ppm Zr, P is in kbar and R is the gas constant, 0.0083144 kJ K−1 . Thermometric results using these equations are shown for a range of geological settings. 相似文献
19.
20.
在简要介绍预选区水文地质条件基础上,主要通过压水试验、抽水试验等水文地质试验得出各种水文地质参数从而分析预选区含水介质渗透性变化特征以及地层渗透性变化规律。 相似文献