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1.
First-principles molecular dynamics simulations of complex material systems such as geophysically relevant oxide and silicate
liquids produce massive amounts of time-varying three-dimensional data for the atomic configurations. Given the high accuracy
of these data, it is desirable to extract as much information hidden in the data as possible. In this paper, we elaborate
on our recently proposed scheme to support interactive visualization at space–time multiresolution of the atomistic simulation
data. Instead of just focusing on direct rendering of the given data, additional data (containing more quantitative and qualitative
information) that usually have to be extracted by some other means are extracted and rendered on the fly. This allows us to
gain better insight into the global as well as local spatio-temporal behavior of the data in the context of bonding, radial
distribution, atomic coordination, clustering, structural stability and distortion, and diffusion. We illustrate such visualization
for the simulation data on the liquid phases of MgO and MgSiO3—the two most abundant components of Earth’s mantle. Our analysis shows that the structure and dynamics of both liquids change
substantially with compression, with no discernible effects of temperature in most cases. 相似文献
2.
Megan Damon Masanori C. Kameyama Michael Knox David H. Porter Dave Yuen Erik O. D. Sevre 《Visual Geosciences》2008,13(1):49-57
The current availability of thousands of processors at many high performance computing centers has made it feasible to carry
out, in near real time, interactive visualization of 3D mantle convection temperature fields, using grid configurations having
10–100 million unknowns. We will describe the technical details involved in carrying out this endeavor, using the facilities
available at the Laboratory of Computational Science and Engineering (LCSE) at the University of Minnesota. These technical
details involve the modification of a parallel mantle convection program, ACuTEMan; the usage of client–server socket based
programs to transfer upwards of a terabyte of time series scientific model data using a local network; a rendering system
containing multiple nodes; a high resolution PowerWall display, and the interactive visualization software, DSCVR. We have
found that working in an interactive visualizastion mode allows for fast and efficient analysis of mantle convection results.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
《地学前缘(英文版)》2022,13(4):101381
Talc is a layered hydrous silicate mineral that plays a vital role in transporting water into Earth’s interior and is crucial for explaining geophysical observations in subduction zone settings. In this study, we explored the structure, equation of state, and elasticity of both triclinic and monoclinic talc under high pressures up to 18 GPa using first principles simulations based on density functional theory corrected for dispersive forces. Our results indicate that principal components of the full elastic constant tensor C11 and C22, shear components C66, and several off-diagonal components show anomalous pressure dependence. This non-monotonic pressure dependence of elastic constant components is likely related to the structural changes and is often manifested in a polytypic transition from a low-pressure polytype talc-I to a high-pressure polytype talc-II. The polytypic transition of talc occurs at pressures within its thermodynamic stability. However, the bulk and shear elastic moduli show no anomalous softening. Our study also shows that talc has low velocity, extremely high anisotropy, and anomalously high VP/VS ratio, thus making it a potential candidate mineral phase that could readily explain unusually high VP/VS ratio and large shear wave splitting delays as observed from seismological studies in many subduction systems. 相似文献
4.
S. Merkel A. P. Jephcoat J. Shu H.-K. Mao P. Gillet R. J. Hemley 《Physics and Chemistry of Minerals》2002,29(1):1-9
Physical properties including the equation of state, elasticity, and shear strength of pyrite have been measured by a series
of X-ray diffraction in diamond-anvil cells at pressures up to 50 GPa. A Birch–Murnaghan equation of state fit to the quasihydrostatic
pressure–volume data obtained from laboratory X-ray source/film techniques yields a quasihydrostatic bulk modulus K
0T
=133.5 (±5.2) GPa and bulk modulus first pressure derivative K
′
0T
=5.73 (±0.58). The apparent equation of state is found to be strongly dependent on the stress conditions in the sample. The
stress dependency of the high-pressure properties is examined with anisotropic elasticity theory from subsequent measurements
of energy-dispersive radial diffraction experiments in the diamond-anvil cell. The calculated values of K
0T
depend largely upon the angle ψ between the diffracting plane normal and the maximum stress axis. The uniaxial stress component
in the sample, t=σ3−σ1, varies with pressure as t=−3.11+0.43P between 10 and 30 GPa. The pressure derivatives of the elastic moduli dC
11/dP=5.76 (±0.15), dC
12/dP=1.41 (±0.11) and dC
44/dP=1.92 (±0.06) are obtained from the diffraction data assuming previously reported zero-pressure ultrasonic data (C
11=382 GPa, C
12=31 GPa, and C
44=109 GPa).
Received: 21 December 2000 / Accepted: 11 July 2001 相似文献
5.
Chondrodite, a member of the humite group of minerals, forms by hydration of olivine and is stable over a range of temperatures
and pressures that includes a portion of the uppermost mantle. We have measured the single crystal elastic properties of a
natural chondrodite specimen at ambient conditions using Brillouin spectroscopy. The isotropic aggregate bulk (K) and shear
(μ) moduli calculated from the single-crystal elastic moduli, Cij, are: KS=118.4(16) GPa and μ=75.6(7) GPa. A comparison of the structures and elasticity of olivine and chondrodite indicate that the
replacement of O with (OH,F) in M2+O6 octahedra has a small effect on the elasticity of humite-group minerals. The slightly diminished elastic moduli of humite-group
minerals (as compared to olivine) are likely caused by a smaller ratio of strong structural elements (SiO4 tetrahedra) to weaker octahedra, and perhaps a more flexible geometry of edge-sharing MO4(O,OH,F)2 octahedra. In contrast to the humite-olivine group minerals, the incorporation of water into garnets and spineloids leads
to a more substantial decrease in the elastic properties of these minerals. This contrasting behavior is due to formation
of O4H4 tetrahedra and vacant hydroxyl-bearing octahedra in the garnets and spineloids, respectively. Therefore, the mechanism of
incorporation of H/OH into mineral phases, not only degree of hydration, should be taken into account when estimating the
effect of water on the elastic properties of minerals. The bulk elastic wave velocities of chondrodite and olivine are very
similar. If humite-like incorporation of OH is predominant in the upper mantle, then the reaction of OH with olivine will
have a minor or possibly no detectable effect on seismic velocities. Thus, it may be difficult to distinguish chondrodite-bearing
rocks from “anhydrous” mantle on the basis of seismically determined velocities for the Earth.
Received: 25 February 1998 / Revised, accepted: 18 August 1998 相似文献
6.
7.
Alexander Kurnosov Hauke Marquardt Leonid Dubrovinsky Vasily Potapkin 《Comptes Rendus Geoscience》2019,351(2-3):280-285
Fiber-based laser heating systems offer high flexibility and are increasingly used in high-pressure/high-temperature research. Previous fiber-based laser heating systems were based on lasers delivering radiation with 1-μm wavelength that show unfavorable heating characteristics for many sample materials. We report on the development and first experiments of a waveguide (fiber)-based CO2-laser heating system that can be used in a flexible manner for high-temperature research and for high-pressure/temperature experiments when combined with diamond-anvil cells. The waveguide-based CO2-laser heating system allows convenient heating of optically transparent samples without the need for adding an additional laser absorber. In a pilot experiment, the flexible heating system has been installed on a Brillouin scattering system to measure high-temperature sound-wave velocities in single-crystal MgO. The waveguide-based CO2-laser heating system offers perspectives for a variety of scientific applications, most importantly those that require the use of synchrotron facilities where space is limited and flexible solutions are required. 相似文献
8.
Stability of various hydrous phases in CMAS pyrolite-H<Subscript>2</Subscript>O system up to 25 GPa 总被引:1,自引:0,他引:1
We carried out a series of melting experiments with hydrous primitive mantle compositions to determine the stability of dense
hydrous phases under high pressures. Phase relations in the CaO–MgO–Al2O3–SiO2 pyrolite with ˜2 wt% of water have been determined in the pressure range of 10–25 GPa and in the temperature range between
800 and 1400 °C. We have found that phase E coexisting with olivine is stable at 10–12 GPa and below 1050 °C. Phase E coexisting
with wadsleyite is stable at 14–16 GPa and below 900 °C. A superhydrous phase B is stable in pyrolite below 1100 °C at 18.5
GPa and below 1300 °C at 25 GPa. No hydrous phases other than wadsleyite are stable in pyrolite at 14–17 GPa and 900–1100
°C, suggesting a gap in the stability of dense hydrous magnesium silicates (DHMS). We detected an expansion in the stability
field of wadsleyite to lower pressures (12 GPa and 1000 °C). The H2O content of wadsleyite was found to decrease not only with increasing temperature but also with increasing pressure. The
DHMS phases could exist in a pyrolitic composition only under the conditions present in the subducting slabs descending into
the lower mantle. Under the normal mantle and hot plume conditions, wadsleyite and ringwoodite are the major H2O-bearing phases. The top of the transition zone could be enriched in H2O in accordance with the observed increase in water solubility in wadsleyite with decreasing pressure. As a consequence of
the thermal equilibration between the subducting slabs and the ambient mantle, the uppermost lower mantle could be an important
zone of dehydration, providing fluid for the rising plumes.
Received: 9 September 2002 / Accepted: 11 January 2003
Acknowledgements The authors are thankful to Y. Ito for the assistance with the EPMA measurement, A. Suzuki, T. Kubo and T. Kondo for technical
help with the high-pressure experiments and Raman and X-ray diffraction measurements and C.R. Menako for technical support.
K. Litasov thanks H. Taniguchi for his continuous encouragement and the Center for Northeast Asian Studies of Tohoku University
and the Japanese Society for the Promotion of Science for the research fellowships. This work was partially supported by the
Grant-in-Aid of Scientific Research of the Priority Area (B) of the Ministry of Education, Science, Sport, and Culture of
the Japanese government (no. 12126201) to E. Ohtani. 相似文献
9.
煤层气地面与井下一体化抽采三维可视化管理系统关键技术 总被引:1,自引:0,他引:1
在对典型矿区不同储层条件下煤层气协调开发技术模式和地面与井下联合高效抽采技术分析总结的基础上,结合人工智能技术,实现了煤层气地面与井下一体化抽采三维可视化管理系统的智能化。根据煤层气地面与井下抽采系统中三维要素的不同特征,分别采用地面建筑物与抽采设备的3DMAX静态建模和基于钻孔数据的地质体动态建模。运用对原始数据进行解析控制插值算法的精度和视窗的消隐与裁剪等技术,实现了三维要素的多角度观察、放大、漫游、旋转、平移、叠加、剥离、透明和纹理处理等可视化功能。系统在晋城矿区寺河区块进行实际应用,取得了良好的效果。 相似文献
10.
南极、北极和青藏高原作为地球的"三极"是全球变化的敏感区和研究热点.随着天空地一体化对地观测技术的快速发展,三极时空信息呈现出海量、高时效、多维度的大数据特征.但由于缺乏有效的可视化手段,这些数据很难被非科研人员理解和认知.如何面向不同人群,快速直观地展示三极最新科学发现所产生的时空数据,已成为数据可视化研究迫切需要解... 相似文献
11.
12.
Four main serpentine varieties can be distinguished on the basis of their microstructures, i.e. lizardite, antigorite, chrysotile and polygonal serpentine. Among these, antigorite is the variety stable under high pressure. In order to understand the structural response of these varieties to pressure, we studied well-characterized serpentine samples by in situ Raman spectroscopy up to 10 GPa, in a diamond-anvil cell. All serpentine varieties can be metastably compressed up to 10 GPa at room temperature without the occurrence of phase transition or amorphization. All spectroscopic pressure-induced changes are fully reversible upon decompression. The vibrational frequencies of antigorite have a slightly larger pressure dependence than those of the other varieties. The O–H-stretching modes of the four varieties have a positive pressure dependence, which indicates that there is no enhancement of hydrogen bonding in serpentine minerals at high pressure. Serpentine minerals display two types of hydroxyl groups in the structure: inner OH groups lie at the centre of each six-fold ring while outer OH groups are considered to link the octahedral sheet of a given 1:1 layer to the tetrahedral sheet of the adjacent 1:1 layer. On the basis of the contrasting behaviour of the Raman bands as a function of pressure, we propose a new assignment of the OH-stretching bands. The strongly pressure-dependent modes are assigned to the vibrations of the outer hydroxyl groups, the less pressure-sensitive peaks to the inner ones. 相似文献
13.
The first pressure derivatives of the second-order elastic constants
have been calculated for brucite, Mg(OH)2 from the second- and third-order elastic constants. The deformation theory and finite strain elasticity theory have been used to obtain the second- and third-order elastic constants of Mg(OH)2 from the strain energy of the lattice. The strain energy ϕ is calculated by taking into account the interactions up to third nearest neighbors in the Mg(OH)2 lattice. ϕ is then compared with the strain dependent lattice energy from continuum model approximation to obtain the expressions of elastic constants. The complete set of six second-order elastic constants C
IJ
of brucite exhibits large anisotropy. Since C
33 (= 21.6 GPa), which corresponds to the strength of the material along the c-axis direction, is less than the longitudinal mode C
11 (= 156.7 GPa), the interlayer binding forces are weaker than the binding forces along the basal plane of Mg(OH)2. The 14 nonvanishing components of the third-order elastic constants, C
IJK
, of brucite have been obtained. All the C
IJK
of brucite are negative except the values of C
114 (= 230.36 GPa), C
124 (= 75.45 GPa) and C
134 (= 36.98 GPa). The absolute values of the C
IJK
are, in general, one order of magnitude greater than the C
IJ
’s in the Mg(OH)2 system as usually expected for a crystalline material. To our knowledge, no previous data are available to compare the pressure derivatives of brucite. The pressure derivatives of the two components viz., C
14 and C
33 become negative
indicating an elastic instability in brucite while under pressure. This may be related to the phase transition of brucite largely involving rearrangements of H atoms revealed in the Raman spectroscopic, powder neutron diffraction and synchrotron X-ray diffraction studies. 相似文献
14.
15.
查明煤中矿物质在不同温度和CO2分压条件下溶解度变化规律,能为注入CO2过程中煤储层渗透率分析提供重要依据。借助水文地球化学模拟软件PHREEQC对在不同温度和CO2分压条件下煤中各矿物的溶解度进行了水化学模拟,得出不同温度和CO2分压条件下矿物质溶解度的变化规律。结果表明:在无CO2分压时,随着温度的升高各矿物的溶解度增加;当溶液中CO2分压增加到一定程度时,随着温度的升高各矿物的溶解度降低(石英除外);在温度相同时,随着CO2分压的增加,所有矿物(石英除外)溶解度均增加,方解石的溶解度随着CO2分压的升高呈现出迅速增加的趋势,其他矿物随着CO2分压的升高,溶解度增加的速率较为缓慢。 相似文献
16.
德南断裂带是山东德南洼陷的主要油气聚集场所 ,精细识别各断层的分布有重要的现实意义。将平面可视化技术应用于德南断裂的精细识别取得了很好的效果 ,已识别出德南断裂是一个向西散开的断裂系 ,它从北到南由 1、 2、 3号北倾断层组成 ;1、 2号断层最终汇聚为一条 ,2号断层下降盘发育 3~ 4条反向补偿断层 ;3号断层是一个小型的断裂系 ,由 5~ 7个北倾断层组成 ,平面上亦向西散开 ;剖面上该断裂系主要反映为向上分开、向下汇聚的帚状断裂系 ;同时还发现了由 3号断裂系控制的断块群。对德南断裂系的精细识别为进一步的钻井勘探和储层建模的研究提供了可靠的依据 相似文献
17.
18.
19.
三维地质建模及可视化系统的设计与开发 总被引:31,自引:7,他引:31
三维地学模拟是三维地质信息GIS可视化的核心内容。基于基础GIS软件平台MAPGIS,利用功能强大的三维可视化开发平台MAPGIS-TDE,设计、开发具有自主版权的三维地质建模及可视化系统。MAPGIS-TDE包括MAPGIS内核模块、MAPGIS-TDE基础平台、MAPGIS-TDE构建平台和基于MAPGIS-TDE的应用系统等4个层次。基于MAPGIS-TDE的三维地质建模及可视化系统分为地质数据管理、二维地质分析、地质断面处理、地质结构建模和地质属性建模等5大功能模块。系统实现时,将空间数据库划分为基础地理图形库、区域地质数据库、工程地质数据库、水文地质数据库、地球物理数据库、地球化学数据库等6类。该系统不仅提供了强大的地质数据管理、三维地质建模以及模型的可视化功能,还为专业技术人员提供了一个可视化的分析、设计平台。 相似文献
20.
多属性融合技术是近年来针对单一属性的局限性而发展起来的一项新技术。通过研究三维空间中多种地震属性体实时融合技术,提出了一种实现方案。采用八叉树结构有效进行数据的动态管理,基于Shader编程技术,利用GPU可编程管线加速,实现多属性体融合的三维可视化。基于该方案,研发了三维可视化多属性体融合系统,实现了基于RGB映射和属性加权的两种融合技术,保证了多属性体高质量实时融合渲染,通过实际应用取得了良好效果。 相似文献