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全球地表热流的产生与分布

全球地表热流的产生与分布

Degree One Loading by Pressure Variations at the CMB

中国科学院地质与地球物理研究所2001学术年会

作者：叶正仁 bradford h.hager 中国科学院地质与地球物理研究所 Department of Earth Atmospheric and Planetary SciencesMassachusetts Institute of Technology

全球地表热流是反映地球内部热与动力学过程的一种主要能流.本文在三维球坐标框架下,就几个不同的粘度模型分别研究地幔内部密度异常(基于全球地震层析结果)以及板块运动激发的地幔流动的热效应及其对于观测地表热流产生和分布特征的贡... 详细信息

全球地表热流是反映地球内部热与动力学过程的一种主要能流.本文在三维球坐标框架下,就几个不同的粘度模型分别研究地幔内部密度异常(基于全球地震层析结果)以及板块运动激发的地幔流动的热效应及其对于观测地表热流产生和分布特征的贡献.由于地幔动力系统具有较高的Pe数,可以期望由板块运动激发的地幔流动将强烈地扰动地幔内部初始传导状态下的温度场以及地表热的热流分布.结果表明,与地幔内部密度异常产生的热效应相比,运动的板块及其激发的地幔流动在全球地表观测热流的产生和分布特征上起着更为重要的作用.观测到的大洋中脊处的高热流在很大程度上可以归因于板块激发的地幔流动的热效应.计算的平均温度剖面较好地揭示了岩石圈和D″层的温度特征,即温度随深度的剧烈变化,这与我们目前通过其他手段对岩石圈和D″层的温度结构了解是一致的.一个下地幔粘度比上地幔高出30倍的粘度结构(文中使用的粘度模型2)较之其余模型的拟合程度似乎更好.

关键词：地表热流地幔流动 Peclet数板块运动大洋中脊

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Journal of Earth Science 2013年第5期24卷 736-749页

作者： Ming Fang bradford h.hager Weijia Kuang Department of Earth Atmospheric & Planetary Sciences Massachusetts Institute of Technology Planetary Geodynamics Laboratory NASA Goddard Space Flight Center

hemispherical asymmetry in core dynamics induces degree-1 pressure variations at the core mantle boundary （CMB）, which in turn deforms the overlaying elastic mantle, at the same time keeps center of mass of the whole Earth stationary in space. We develop a systematic procedure to deal with the degree-1 CMB pressure loading. We find by direct calculation a surprisingly negative load Love number h1=-1.425 for vertical displacement. Further analysis indicates that the negative hi corre- sponds to thickening above the positive load that defies intuition that pressure inflation pushes over- laying material up and thins the enveloping shell. We also redefine the pressure load Love numbers in general to enable comparison between the surface mass load and the CMB pressure load for the whole spectrum of harmonic degrees. We find that the gravitational perturbations from the two kinds of loads at degrees n〉l are very similar in amplitude but opposite in sign. In particular, if the CMB pressure variation at degree 2 is at the level of -1 hpa/yr （1 cm water height per year）, it would perturb the variation of Earth＇s oblateness, known as the J2, at the observed level.

关键词： Degree One Loading by Pressure Variations at the CMB MRSP

Reverse-Time Prestack Depth Migration of GPR Data from Topography for Amplitude Reconstruction in Complex Environments

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Journal of Earth Science 2015年第6期26卷 791-798页

作者： John h.bradford Center for Geophysical Investigation of the Shallow Subsurface Boise State University

With increased computational power, reverse-time prestack depth migration（RT-PSDM） has become a preferred imaging tool in seismic exploration, yet its use has remained relatively limited in ground-penetrating radar（GPR） applications. Complex topography alters the wavefield kinematics making for a challenging imaging problem. Model simulations show that topographic variation can substantially distort reflection amplitudes due to irregular wavefield spreading, attenuation anomalies due to irregular path lengths, and focusing and defocusing effects at the surface. The effects are magnified when the topographic variations are on the same order as the depth of investigation––a situation that is often encountered in GPR investigations. here, I use a full wave-equation RT-PSDM algorithm to image GPR data in the presence of large topographic variability relative to the depth of investigation. The source and receiver wavefields are propagated directly from the topographic surface and this approach inherently corrects for irregular kinematics, spreading and attenuation. The results show that when GPR data are acquired in areas of extreme topography, RT-PSDM can accurately reconstruct reflector geometry as well as reflection amplitude.

关键词： reverse-time prestack depth migration ground-penetrating radar topography wavefield reflector geometry reflection amplitude.

Large-amplitude dust acoustic solitons in an opposite polarity dusty plasma with generalized polarization force

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Chinese Physics B 2022年第1期31卷 199-207页

作者： Mahmood A.h.Khaled Mohamed A.Shukri Yusra A.A.hager Department of Physics Faculty of Education(Al-Mahweet)Sana'a UniversitySana'aYemen Department of Physics Faculty of ScienceSana'a UniversitySana'aYemen Department of Physics Faculty of EducationSana'a UniversitySana'aYemen

Linear and nonlinear dust acoustic(DA)waves have been investigated in an opposite polarity dusty plasma comprising negatively and positively charged dust grains,Maxwellian electrons and ions,including the generalized polarization force *** properties of linear DA waves have been significantly altered by the dual dust polarity and polarization *** amplitude DA solitons have been discussed in the framework of the Sagdeev potential *** results show that both rarefactive and compressive solitons can exist in such a dusty *** basic features of the Sagdeev potential have been examined under the effect of the polarization force parameter R,the ratio of the charge number of the positive dust to that of the negative dust Z,and the Mach number *** results show that these parameters play a significant role in determining the region of existence of large amplitude DA solitons.

关键词： large amplitude opposite polarity dusty plasma polarization force

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板块动力和地幔对流的一个简单的地球模型

世界地质 1985年第2期 41-77页

作者： bradford h.hager Richard J.O'Conilell 周富祥董焕成

岩石圈板块随着年代的冷却,变厚并消亡,引起大规模水平密度不均匀,势必导致板块运动和地幔流动。我们用与这些密度不均匀有关的量来确定它们能否引起观察到的板块运动。首先,计算二度模型来估算所设的流

关键词：岩石圈板块牵引力边界条件板块运动板块边界块体海岭俯冲带软流层行走力外力地球动力学板块边缘洋脊太平洋板块大洋岩石圈

Trading in your spindles for blebs： the amoeboid tumor cell phenotype in prostate cancer

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Asian Journal of Andrology 2014年第4期16卷 530-535页

作者： Samantha Morley Martin h.hager Sara G Poilan Beatrice Knudsen Dolores Di Vizio Michael R Freeman Division of Cancer Biology and Therapeutics Departments of Surgery Medicine and Biomedical Sciences and The Samuel Oschin Comprehensive Cancer Institute Cedars-Sinai Medical Center Los Angeles CA Urological Diseases Research Center Boston Children's Hospital Boston MA Department of Surgery Harvard Medical School Boston MA Department of Medicine David Geffen School of Medicine University of California Los Angeles CA USA.

Prostate cancer （PCa） remains a principal cause ofmortalityin developed *** no clinical interventions overcome resistance to androgen ablation therapy, management of castration resistance and metastatic disease remains largely untreatable. Metastasis is a multistep process in which tumor cells lose cell-cell contacts, egress from the primary tumor, intravasate, survive shear stress within the vasculature and extravasate into tissues to colonize ectopic sites. Tumor ceils reestablish migratory behaviors employed during nonneoplastic processes such as embryonic development, leukocyte trafficking and wound healing. While mesenchymal motility is an established paradigm of dissemination, an alternate, ＇amoeboid＇ phenotype is increasingly appreciated as relevant to human cancer.

关键词： @@

Structure, Thermal Behavior and Characterization of a New hybrid Iron Fluoride FeF4（2,2′-bipyridine）（h2O）2

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Chemical Research in Chinese Universities 2015年第1期31卷 16-20页

作者： Mouna SMIDA hager LITAIEM Mohamed DAMMAK Santiago GARCIA-GRANDA Laboratoire de Chimie Inorganique Faculte des Sciences de Sfax Universite de Sfax 3000Sfax Tunisie Departement de Chimie Physique Analytique Faculte de Chimie Universite d'Oviedo-CINN 33006 Oviedo Spain

New crystal of FeF4（2,2′-bipyridine）（h2O）2 was prepared by hydrothermal synthesis. Crystalline structure determination is performed from single crystal X-ray diffraction data. The unit cell is monoclinic space group P21/n, with cell parameters a=0.9046（5） nm, b=0.7502（5） nm, c=1.9539（5） nm,β=93.307（5）°, V=1.3238（12） nm^3 and Z=4. The structure of FeF4（2,2＇-bipyridine）（h2O）2 is built up from FeF4N2 octahedra coordinated by two nitrogen atoms of the 2,2＇-bipyridine molecules, and four fluorine atoms as well as uncoordinated h2O molecules. Thermal analysis of the title compound showed that the decomposition introduced four steps. IR spectra confirmed the presence of 2,2＇-bipyridine molecules. The optical absorption was measured at the corresponding 2max using UV-Vis diffuse reflectance spectrum.

关键词： hydrothermal synthesis hybrid Iron fluoride

Reverse-Time Migration from Rugged Topography to Image Ground-Penetrating Radar Data in Complex Environments

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Engineering 2018年第5期4卷 661-666页

作者： John h. bradford Janna Privette David Wilkins Richard Ford Department of Geosciences Boise State University Boise ID 83725-1535 USA Department of Geosciences Weber State University Ogden UT 84408-2507 USA

In ground-penetrating radar （GPR） imaging, it is common for the depth of investigation to be on the same order as the variability in surface topography, In such cases, migration fails when it is carried out from a datum after the application of elevation statics, We introduce a reverse-time migration （RTM） algorithm based on the second-order decoupled form of Maxwell＇s equations, which requires computation of only the electric field, The wavefield extrapolation is computed directly from the acquisition surface without the need for datuming, In a synthetic case study, the algorithm significantly improves image accuracy over a processing sequence in which migration is performed after elevation statics, In addition, we acquired a field dataset at the Coral Pink Sand Dunes （CPSD） in Utah, USA, The data were acquired over rugged topography and have the complex internal stratigraphy of multiply eroded, modern, and ancient eolian deposits, The RTM algorithm significantly improves radar depth images in this challenging environment,

关键词： Ground-penetrating radar Reverse-time migration Sand dune Amplitude analysis

higher-Order Interactions： Understanding the knowledge capacity of social groups using simplicial sets

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Current Zoology 2015年第1期61卷 114-127页

作者： bradford R GREENING Jr Noa PINTER-WOLLMAN Nina h FEFFERMAN Department of Ecology Evolution and Natural Resources Rutgers University New Brunswick NJ 08901 USA BioCircuits Institute University of Califomia at San Diego 9500 Gilman Dr. Mail Code 0328 La Jolla CA 92093 USA DIMACS Rutgers University 96 Frelinghuysen Road Piscataway NJ 08854 USA

A predominant benefit of social living is the ability to share knowledge that cannot be gained through the information an individual accumulates based on its personal experience alone. Traditional computational models have portrayed sharing knowledge through interactions among members of social groups via dyadic networks. Such models aim at understanding the percolation of information among individuals and groups to identify potential limitations to successful knowledge transfer. how- ever, because many real-world interactions are not solely pairwise, i.e., several group members may obtain information from one another simultaneously, it is necessary to understand more than dyadic communication and learning processes to capture their full complexity. We detail a modeling framework based on the simplicial set, a concept from algebraic topology, which allows elegant encapsulation of multi-agent interactions. Such a model system allows us to analyze how individual information within groups accumulates as the group＇s collective set of knowledge, which may be different than the simple union of individually contained information. Furthermore, the simplicial modeling approach we propose allows us to investigate how information accumulates via sub-group interactions, offering insight into complex aspects of multi-way communication systems. The fundamental change in modeling strategy we offer here allows us to move from portraying knowledge as a ＂token＂, passed from signaler to receiver, to portraying knowledge as a set of accumulating building blocks from which novel ideas can emerge. We provide an explanation of relevant mathematical concepts in a way that promotes accessibility to a general audience [Current Zoology 61 （1）： 114--127, 2015].

关键词： Collective decision making Communication Cultural transmission Information flow Simplex Social learning