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Transition Operator Approach to Seismic Full-Waveform Inversion in Arbitrary Anisotropic Elastic Media

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Communications in Computational Physics 2020年第6期28卷 297-327页

作者： morten jakobsen Ivan Psencık Einar Iversen Bjørn Ursin Department of Earth Science University of BergenNorway Institute of Geophysics Czech Academy of SciencesCzech Republic Department of Geoscience and Petroleum NTNU and F.University of BahiaBrazil

We generalize the existing distorted Born iterative T-matrix(DBIT)method to seismic full-waveform inversion(FWI)based on the scalar wave equation,so that it can be used for seismic FWI in arbitrary anisotropic elastic media with variable mass densities and elastic stiffness *** elastodynamic wave equation for an ar-bitrary anisotropic heterogeneous medium is represented by an integral equation of the Lippmann-Schwinger type,with a 9-dimensional wave state(displacement-strain)*** solve this higher-dimensional Lippmann-Schwinger equation using a transition operator formalism used in quantum scattering *** allows for domain decomposition and novel variational *** tensorial nonlinear inverse scat-tering problem is solved iteratively by using an expression for the Fŕechet derivatives of the scattered wavefield with respect to elastic stiffness tensor fields in terms of modified Green’s functions and wave state vectors that are updated after each *** the generalized DBIT method is consistent with the Gauss-Newton method,it incorporates approximate Hessian information that is essential for the reduction of multi-parameter cross-talk *** DBIT method is implemented efficiently using a variant of the Levenberg-Marquard method,with adaptive selection of the regularization parameter after each *** a series of numerical experiments based on synthetic waveform data for transversely isotropic media with vertical symmetry axes,we obtained a very good match between the true and inverted models when using the traditional Voigt *** suggests that the effects of cross-talk can be sufficiently reduced by the incorporation of Hessian information and the use of suitable regularization *** the generalized DBIT method for FWI in anisotropic elastic media is naturally target-oriented,it may be particularly suitable for applications to seismic reservoir characterization and ***,the theory a

关键词： Waveform inversion time-lapse seismic seismic inverse scattering target-oriented inversion Green’s function

Vortex lattices in type-II superconductors studied by small-angle neutron scattering

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Frontiers of physics 2011年第4期6卷 398-409页

作者： morten Ring Eskildsen Department of Physics University of Notre Dame Notre Dame IN 46556 USA

Here we review recent small-angle scattering studies of the vortex lattice in a range of type-II superconductors carried out by our group. Emphasis is placed on providing examples of the kind of information which can be obtained by such measurements, focusing in particular on studies of the vortex lattice structure and form factor in LuNi2B2C, TmNi2B2C, CeCoIn5 and Ba（Fe0.93Co0.07）2As2.

关键词： superconductivity vortex lattice small-angle neutron scattering borocarbides pnic-tides CeCoIn5

OPTIMAL CONTROL OF THE LAPLACE-BELTRAMI OPERATOR ON COMPACT SURFACES： CONCEPT AND NUMERICAL TREATMENT

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Journal of Computational Mathematics 2012年第4期30卷 392-403页

作者： Michael Hinze morten Vierling Schwerpunkt Optimierung und Approximation Universit~it Hamburg Bundesstrafle 55 20146 Hamburg Germany

We consider optimal control problems of elliptic PDEs on hypersurfaces F in R^n for n = 2, 3. The leading part of the PDE is given by the Laplace-Beltrami operator, which is discretized by finite elements on a polyhedral approximation of F. The discrete optimal control problem is formulated on the approximating surface and is solved numerically with a semi-smooth Newton algorithm. We derive optimal a priori error estimates for problems including control constraints and provide numerical examples confirming our analytical findings.

关键词： Elliptic optimal control problem Laplace-Beltrami operator Surfaces Controlconstraints Error estimates Semi-smooth Newton method.

Contact Electrification by Quantum-Mechanical Tunneling

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Research 2019年第1期2019卷 742-752页

作者： morten Willatzen Zhong Lin Wang CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100083China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332-0245USA

A simple model of charge transfer by loss-less quantum-mechanical tunneling between two solids is *** model is applicable to electron transport and contact electrifcation between e.g.a metal and a dielectric *** on a one-dimensional efective-mass Hamiltonian,the tunneling transmission coefcient of electrons through a barrier from one solid to another solid is calculated *** transport rate(current)of electrons is found using the Tsu-Esaki equation and accounting for diferent Fermi functions of the two *** show that the tunneling dynamics is very sensitive to the vacuum potential versus the two solids conduction-band edges and the thickness of the vacuum *** relevant time constants for tunneling and contact electrifcation,relevant for triboelectricity,can vary over several orders of magnitude when the vacuum gap changes by one order of magnitude,say,1˚A to 10˚*** repulsion between electrons on the lef and right material surfaces is accounted for in the tunneling dynamics.

关键词： tunneling solids vacuum

Clustering and classification of energy meter data: A comparison analysis of data from individual homes and the aggregated data from multiple homes

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Building Simulation 2021年第1期14卷 103-117页

作者： Juan Sala Rongling Li morten H.Christensen Department of Civil Engineering Technical University of DenmarkLyngbyDenmark Department of Electrical Engineering Technical University of DenmarkLyngbyDenmark

The transition towards a more sustainable environment requires the development of new control systems on the demand side to integrate renewable energy sources into the energy *** this purpose,energy meter data of homes have been broadly used in modelling,forecast and optimal control of energy ***,usability and reliability of household energy meter data have not been specifically *** this study,we apply commonly used machine learning methods on the heating consumption data of(1)two individual homes in an apartment building and(2)the district heating substation of the apartment building which includes 72 homes,to identify how the characteristics of data affect the result of data *** clustering approaches were applied using the K-means algorithm to group similar heating daily *** the clustering results,different classification algorithms such as logistic regression and random forest were applied to predict the heating consumption level with regards to the weather *** data analysis process showed that the substation data which is the aggregated heating consumption of the 72 homes is more reliable and valid for energy prediction than the data from two individual *** is due to the large variation and uncertainty in the daily energy use of individual homes.

关键词： smart meter data daily profile clustering classification data usability heat substation

Modeling and optimization of a spherical triboelectric generator

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Nano Research 2023年第9期16卷 11925-11931页

作者： Jens Gravesen morten Willatzen Jiajia Shao Zhong Lin Wang DTU Compute Technical University of DenmarkKgs.LyngbyDK-2800Denmark Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China Georgia Institute of Technology AtlantaGeorgia 30332USA

A detailed geometric analysis of spherical triboelectric nanogenerators is *** comparison with earlier works on spherical triboelectric generators,the general case where the moving dielectric rolls on the inside surface of the larger sphere of the TENG is discussed in terms of maximum energy *** optimization analysis of geometrical parameters allows various cases of electrode geometry,either in the form of a spherical circle,spherical ellipse,spherical rectangle,or spherical isosceles trapezium,to be *** analytical insight and computational effective models provided by differential geometry make the mathematical model superior compared to standard three-dimensional(3D)numerical methods.

关键词： spherical triboelectric nanogenerator differential geometry analysis electrode shape study modeling and optimization

Understanding Contact Electrification at Water/Polymer Interface

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Research 2022年第2期2022卷 323-332页

作者： Yang Nan Jiajia Shao morten Willatzen Zhong Lin Wang Bijing Institute of Nanocenergy and Nantosystems Chinese Academny of SciencesBeijing 101400China School of Nanosience and Techmology University of Chinese Academy of SciencesBeiing 100049China CUSTech Instiute WenzhouZhejiang 325024China School of Materials Science and Enginering Georgia Institute of TcnologrAtlantaGreorgia 30332-0245USA

Contact electrifcation(CE)involves a complex interplay of physical interactions in realistic material *** this reason,scientific consensus on the qualitative and quantitative importance of different physical mechanisms on CE remains a formidable *** CE mechanism at a water/polymer interface is a crucial challenge owing to the poor understanding of charge transfer at the atomic ***-principle density functional theory(DFT),used in the present work,proposes a new paradigm to address CE Our results indicate that CE fllows the same trend as the gap between the highest occupied and lowest unoccupied molecular orbitals(HOMO and LUMO)of *** transfer occurs at the outmost atomic layer of the water/polymer interface and is closely linked to the functional groups and atom *** the polymer chains are parallel to the water layer,most electrons are transferred;conversely,if they are perpendicular to each other,the transfer of charges can be *** demonstrate that a decrease in the inerface distance between water and the polymer chains leads to CE in quantitative agreement with the electron cloud overlap model.W'e finally use DFT calculations to predict the properies of CE materials and their potential for triboeletric nanogenerator energy harvesting devices.

关键词： occupied chains polymer

＂Who Is Reciting the Name of the Buddha？＂ as Gongan in Chinese Chan Buddhism

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Frontiers of History in China 2013年第3期8卷 366-388页

作者： morten Schlutter Department of Religious Studies The University of Iowa Iowa City IA 52242 USA

Chart Buddhism＇s ambivalent relationship with language and literature is perhaps most starkly seen in its practice of gongan meditation. This practice was first instituted by the famous Linji master Dahui and involves an intense meditational focus on the ＂punch line＂（huatou） of what is typically a story about an ancient Chan master or an enigmatic question like ＂why did [the legendary founder of Chan] Bodhidharrna come from the West？＂ In the Ming dynasty, a new gongan became widely used in Chart meditation： the phrase ＂who is reciting the name of the Buddha？＂ This was a reference to the widespread practice of chanting homage to the Buddha Amitgbha in hope of getting reborn into his paradise. In using this new gongan, Chan seemingly embraced oral practice in an unprecedented move and appeared to combine the other-power of Amitgbha worship with the self-power of Chan meditation. Scholars have struggled to understand this development, and several have dismissed it as an example of the degeneration of Chan and its later pandering to lay people. I argue that the development of this gongan can best be seen as an attempt to reframe the practice of Buddha-recitation in a Chan meditative framework; and further explore the rationale for the practice as given by the influential Buddhist thinker Yunqi Zhuhong, who was a staunch advocate of Buddha-recitation.

关键词： Dahui Zonggao Song huatou nianfo Yunqi Zhuhong

Comparing corneal outcome between femtosecond laser-assisted cataract surgery and conventional phaco surgery in Fuchs’endothelial dystrophy patients:a randomized pilot study with 6mo follow up

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International Journal of Ophthalmology(English edition) 2021年第5期14卷 684-692页

作者： Therese Krarup Kathrine Rose Aurore Marie-Laurence AkpeMensah morten la Cour Lars morten Holm Department of Ophthalmology Rigshospitalet-Glostrup Valdemar Hansens Vej 1-23Glostrup 2600Denmark

AIM:To compare the corneal outcome in Fuchs’endothelial dystrophy(FED)patients between femtosecond laser-assisted cataract surgery(FLACS)and conventional phaco surgery(CPS).METHODS:This was a randomized controlled study comparing one eye surgery by FLACS and the contralateral eye operated by CPS(stop and chop technique)in FED *** corneal thickness,corneal light backscatter,corneal densitometry,and central corneal endothelial cell count and hexagonality(noncontact endothelial cell microscope),and corrected distance visual acuity(CDVA)were assessed preoperatively and at day 1,40,and 180 ***:Totally 31 patients(16 women)were *** day 40 postoperatively,the mean endothelial cell loss(ECL)was 23.67%by FLACS and 17.30%by CPS(P=0.53).At day 180 postoperatively,ECL was 25.58%in FLACS and 21.32%in CPS(P=0.69).Densitometry data in all layers and all annuli from anterior layer to posterior layer in annuli 0-2,2-6,6-10 and 10-12,total densitometry with all layers and all annuli was performed.A significant difference was found in 6-10(posterior layer)at day 1 with-1.42 grayscale units(GSU;95%CI:-2.66 to-0.19,P=0.02).In 10-12(anterior layer,central layer and all layers)at day 40 were significant different with 7.7(95%CI:1.89 to 13.50,P=0.009),3.97(95%CI:0.23 to 7.71,P=0.03),4.73 GSU(95%CI:0.71 to 8.75,P=0.02),*** the remaining parameters we found no difference between the two groups(P>0.05).Three CPS eyes suffered from corneal ***:There is no significant difference in corneal outcome between FLACS and *** cell density and pentacam corneal outcome may be inadequate as outcome parameters in FED patients.

关键词： cataract surgery femtosecond-assisted cataract surgery corneal endothelial cell loss central corneal thickness pentacam Fuchs’endothelial dystrophy