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Small-Scale Mineralogical Heterogeneity from variations in Phase Assemblages in the Transition Zone and D" Layer Predicted by Convection Modelling

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Journal of Earth Science 2011年第2期22卷 160-168页

作者： Arie P van den Berg David A Yuen Michael H G Jacobs maarten v de hoop Earth Sciences department Utrecht University department of Geology and Geophysics and Minnesota Supercomputing Institute University of MinnesotaMinneapolisMN 55415USA Institut für Metallurgie TU ClausthalClausthal-ZellerfeldGermany department of Mathematics and Center of Applied and Computational Mathematics Purdue UniversityWest LafayetteINUSA

Small-scale heterogeneity in the deep mantle is concentrated in the upper-mantle transition zone （TZ）, in the depth range 410-660 km and also at the bottom 250 km D＂ region. This encourages a more detailed investigation of the potential for seismic reflectivity imaging by modelling heterogeneous structures in mantle convection models including phase transitions of the TZ and D＂ regions. We applied finite elements with variable spacing near the boundary layers in 2-D cylindrical geometry that allow for sufficient spatial resolution. We investigated several models including an extended Boussinesq （EBA） model, focused on the D＂ region, and a compressible （ALA） model for the TZ region. The results for the D＂ region show typical lens-shaped structures of post-perovskite （PPv） embedded in the perovskite （Pv） background mantle, where the thickness of the lenses, at 200-400 km, strongly depends on the Clapeyron slope of the Pv-PPv transition. A second phase transition （double crossing） occurs in case the core temperature is higher than the intercept temperature Ti. Our phase-dependent rheology results in contrasting effective viscosity between Pv and PPv. Our model results reveal a distinctly clear mechanical weakening of the PPv lenses with about an order of magnitude lower viscosity. The shear wave-speed distributions computed from our convection results are strongly correlated with the heterogeneous distribution of the mineral phase. Gradients in the seismic wave-speed that are the target of seismological reflectivity imaging are clearly revealed. The wave-speed results show a clear resolution of the top and bottom interfaces of the PPv lenses. Our ALA model for the TZ is based on a thermodynamical model for the magnesium end- member of an olivine-pyroxene mantle. The model predicts a much more complex distribution of mineral phases, compared to our D＂ results, in agreement with the greater number of mineral phases involved in the olivine-pyroxene phase diagram for the P

关键词： mantle convection phase transition post-perovskite mineralogical heterogeneity.

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各向异性介质中的多参数DMO／TZO

各向异性介质中的多参数DMO／TZO

Theorems of Erds-Ko-Rado type in geometrical settings

美国勘探地球物理学家学会第66届年会

作者： maarten v．de hoop Tariq Alkhalifah 朱成宏 Colorado School of Mines Colorado School of Mines

在过去的十多年里,DMO处理的运动学或射线几何学原理已经完全确立,然而,有关振幅方面的原理只是现在才引起注意。本文的目的在于把克希霍夫型式的TZO和DMO处理推广到弹性介质,并发展动力学上正确的波场数据转换方法。我们籍助广义拉冬...

在过去的十多年里,DMO处理的运动学或射线几何学原理已经完全确立,然而,有关振幅方面的原理只是现在才引起注意。本文的目的在于把克希霍夫型式的TZO和DMO处理推广到弹性介质,并发展动力学上正确的波场数据转换方法。我们籍助广义拉冬变换（GRT）实现这一目标。我们考虑一般的各向异性介质,提出背景均一介质情况的闭型表达式。

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Science China Mathematics 2013年第7期56卷 1333-1348页

作者： de BOECK maarten STORME Leo department of Mathematics Krijgslaan 281-Building S22 9000 GentFlanders Belgium

The original Erds-Ko-Rado problem has inspired much research. It started as a study on sets of pairwise intersecting k-subsets in an n-set, then it gave rise to research on sets of pairwise non-trivially intersecting k-dimensional vector spaces in the vector space v (n, q) of dimension n over the finite field of order q, and then research on sets of pairwise non-trivially intersecting generators and planes in finite classical polar spaces. We summarize the main results on the Erds-Ko-Rado problem in these three settings, mention the Erds-Ko-Rado problem in other related settings, and mention open problems for future research.

关键词：鄂尔多斯雷达表瑞士设置几何定理表型向量空间

Machine learning potentials for metal-organic frameworks using an incremental learning approach

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npj Computational Materials 2023年第1期9卷 2147-2154页

作者： Sander vandenhaute maarten Cools-Ceuppens Simon deKeyser Toon verstraelen veronique van Speybroeck Center for Molecular Modeling Ghent UniversityTechnologiepark 469052 ZwijnaardeBelgium

Computational modeling of physical processes in metal-organic frameworks(MOFs)is highly challenging due to the presence of spatial heterogeneities and complex operating conditions which affect their *** functional theory(DFT)may describe interatomic interactions at the quantum mechanical level,but is computationally too expensive for systems beyond the nanometer and picosecond ***,we propose an incremental learning scheme to construct accurate and data-efficient machine learning potentials for *** scheme builds on the power of equivariant neural network potentials in combination with parallelized enhanced sampling and on-the-fly training to simultaneously explore and learn the phase space in an iterative *** only a few hundred single-point DFT evaluations per material,accurate and transferable potentials are obtained,even for flexible frameworks with multiple structurally different *** incremental learning scheme is universally applicable and may pave the way to model framework materials in larger spatiotemporal windows with higher accuracy.

关键词： framework incremental neural

demonstration of tantalum as a structural material for MEMS thermal actuators

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Microsystems & Nanoengineering 2021年第1期7卷 85-97页

作者： Longchang Ni Ryan M.Pocratsky maarten P.de Boer CMU Mechanical Engineering dept. 5000 Forbes Ave.PittsburghPA 15213USA Present address:Fischione Instruments 9003 Corporate CirExportPA 15632USA

This work demonstrates the processing,modeling,and characterization of nanocrystalline refractory metal tantalum(Ta)as a new structural material for microelectromechanical system(MEMS)thermal actuators(TAs).Nanocrystalline Ta films have a coefficient of thermal expansion(CTE)and Young’s modulus comparable to bulk Ta but an approximately ten times greater yield *** mechanical properties and grain size remain stable after annealing at temperatures as high as 1000°*** has a high melting temperature(Tm=3017℃)and a low resistivity(ρ=20µΩcm).Compared to TAs made from the dominant MEMS material,polycrystalline silicon(polysilicon,Tm=1414℃,ρ=2000µΩcm),Ta TAs theoretically require less than half the power input for the same force and displacement,and their temperature change is half that of *** TAs operate at a voltage 16 times lower than that of other TAs,making them compatible with complementary metal oxide semiconductors(CMOS).We selectα-phase Ta and etch 2.5-μm-thick sputterdeposited films with a 1μm width while maintaining a vertical sidewall profile to ensure in-plane movement of TA *** is 25 times thicker than the thickest reactive-ion-etchedα-Ta reported in the technical *** stress sensitivities to sputter parameters and to hydrogen incorporation are investigated and ***,a v-shaped TA is fabricated and tested in *** conventional actuation by Joule heating and passive self-actuation are as predicted by models.

关键词： thermal structural thick

Machine Learning in Chemical Engineering:Strengths,Weaknesses,Opportunities,and Threats

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Engineering 2021年第9期7卷 1201-1211页

作者： maarten R.Dobbelaere Pieter P.Plehiers Ruben van de vijver Christian v.Stevens Kevin M.van Geem Laboratory for Chemical Technology Department of MaterialsTextiles and Chemical EngineeringGhent UniversityGhent 9052Belgium SynBioC Research Group Department of Green Chemistry and TechnologyFaculty of Bioscience EngineeringGhent UniversityGhent 9000Belgium

Chemical engineers rely on models for design,research,and daily decision-making,often with potentially large financial and safety *** efforts a few decades ago to combine artificial intelligence and chemical engineering for modeling were unable to fulfill the *** the last five years,the increasing availability of data and computational resources has led to a resurgence in machine learning-based *** recent efforts have facilitated the roll-out of machine learning techniques in the research field by developing large databases,benchmarks,and representations for chemical applications and new machine learning *** learning has significant advantages over traditional modeling techniques,including flexibility,accuracy,and execution *** strengths also come with weaknesses,such as the lack of interpretability of these black-box *** greatest opportunities involve using machine learning in time-limited applications such as real-time optimization and planning that require high accuracy and that can build on models with a self-learning ability to recognize patterns,learn from data,and become more intelligent over *** greatest threat in artificial intelligence research today is inappropriate use because most chemical engineers have had limited training in computer science and data ***,machine learning will definitely become a trustworthy element in the modeling toolbox of chemical engineers.

关键词： Artificial intelligence Machine learning Reaction engineering Process engineering

Using modular 3D digital earth applications based on point clouds for the study of complex sites

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International Journal of Digital Earth 2016年第12期9卷 1135-1152页

作者： Oscar Martinez-Rubi Maurice de Kleijn Stefan verhoeven Niels Drost Jisk Attema maarten van Meersbergen Rob van Nieuwpoort Rens de Hond Eduardo Dias Pjotr Svetachov Netherlands eScience Center AmsterdamThe Netherlands Spatial Information laboratory(SPINlab) VU University AmsterdamAmsterdamThe Netherlands Faculty of Arts Institute for HistoricalLiterary and Cultural studies(HLCS)Radboud UniversityNijmegenThe Netherlands Geodan b.v. AmsterdamThe Netherlands Donald Smits Center for Information Technology University of GroningenGroningenThe Netherlands

This article discusses the use of 3D technologies in digital earth applications(deAs)to study complex *** are large areas containing objects with heterogeneous shapes and semantic *** study proposes that deAs should be modular,have multi-tier architectures,and be developed as Free and Open Source Software if *** deAs requiring high reliability in the 3D measurements,point clouds are proposed as basis for the 3D Digital digital earth *** the development of deAs,we propose to follow a workflow with four components:data acquisition and processing,data management,data analysis and data *** every component,technological challenges of using 3D technologies are identified and solutions applied for a case study are *** case study is a modular 3D deA developed for the archaeological project Mapping the via *** 3D deA allows archaeologists to virtually analyze a complex study area.

关键词： 3D digital earth application point clouds data management visualization

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固体地球科学中基于数据驱动发现的机器学习

世界地震译丛 2020年第1期 3-21页

作者： K.J.Bergen P.A.Johnson M.v.de hoop G.C.Beroza

通过固体地球科学各个领域了解地球运转状态是一项日益重要的任务。了解地球运行状态所需的复杂的环境、相互作用和多尺度的过程使它具有挑战性,同时,几乎所有地球的地下都难以直接观测,这也是具有挑战性的原因。数据可用性的大幅增加...

通过固体地球科学各个领域了解地球运转状态是一项日益重要的任务。了解地球运行状态所需的复杂的环境、相互作用和多尺度的过程使它具有挑战性,同时,几乎所有地球的地下都难以直接观测,这也是具有挑战性的原因。数据可用性的大幅增加和计算机模拟越来越逼真的特点给加快进展带来了希望,但是,基于这些功能的加深了解本身就具有挑战性。机器学习将在这一努力中发挥关键作用。我们综述该领域的现状,并就如何扩大和加快进展提出了建议。

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Analysis of Impurity density in the Structure of Arsenopyrite of the Panimba deposit

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矿物学报 2013年第S1期33卷 94-94页

作者： victor v.Onufrienok maarten A.T.M.Broekmans Siberian Federal University Institute of MineralogyGeology and MiningKrasnoyarsky's rabochy av.95 KrasnoyarskRussian Federation Geological Survey of Norway Dept.of Industrial Minerals and MetalsPO Box 63125 SluppenN-7491 TrondheimNorway

Based on comprehensive analysis of the crystal structure, chemical and phase composition of natural arsenopyrite of the "Panimba" deposit (Krasnoyarsk region), an analytical expression for calculating the impurity den... 详细信息

关键词： gold impurity density arsenopyrite chemical compound crystal structure theoretical calculations