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A Numerical Investigation for a Model of the Solid-Gas Phase in a Crystal Growth Apparatus

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Communications in Computational Physics 2008年第4期3卷 913-934页

作者： Jurgen geiser Humboldt-Universitat zu Berlin Department of Mathematics Unter den Linden 6D-10099 BerlinGermany.

We present discretization and solver methods for a model of the solid-gas phase in a crystal growth *** model equations are coupled Eulerian and heat-transfer equations with flux boundary *** a more detailed discussion we consider simpler equations and present time-and space-decomposition methods as solver methods to decouple the multi-physics *** present the error analysis for the discretization and solver *** experiments are performed for the Eulerian and heat-transfer equation using decomposition *** present a real-life application of a crystal growth apparatus,based on underlying stationary heat *** we discuss further error analysis and application to a more complex model of crystal growth.

关键词： Decomposition methods finite-volume discretization error analysis heat equation crystal growth.

Multi-Product Expansion with Suzuki’s Method: Generalization

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Numerical Mathematics(Theory,Methods and Applications) 2011年第1期4卷 68-91页

作者： Jürgen geiser Department of Mathematics Humboldt University of BerlinUnter den Linden 6D-10099 BerlinGermany

In this paper we discuss the extension to exponential splitting methods withrespect to time-dependent operators. We concentrate on the Suzuki’s method, whichincorporates ideas to the time-ordered exponential of [3, 11, 12, 34]. We formulate themethods with respect to higher order by using kernels for an extrapolation scheme. Theadvantages include more accurate and less computational intensive schemes to specialtime-dependent harmonic oscillator problems. The benefits of the higher order kernelsare given on different numerical examples.

关键词： Suzuki’s method multiproduct expansion multiplicate and additive splitting schemes exponential splitting

Monte Carlo Simulations of Elastic Scattering with Applications to DC and High Power Pulsed Magnetron Sputtering for Ti3_(S)iC_(2)

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Communications in Computational Physics 2012年第5期11卷 1618-1642页

作者： Jurgen geiser Sven Blankenburg Department of Mathematics Humboldt-Universitat zu BerlinD-10099 BerlinGermany Department of Physics Humboldt-Universitat zu BerlinD-10099 BerlinGermany.

We simulate the particle transport in a thin film deposition process made by PVD(physical vapor deposition)and present several models for projectile and target collisions in order to compute the mean free path and the differential cross section(angular distribution of scattered projectiles)of the scattering process.A detailed description of collision models is of the highest importance in Monte Carlo simulations of high power impulse magnetron sputtering and DC *** derive an equation for the mean free path for arbitrary interactions(cross sections)that includes the relative velocity between the *** apply our results to two major interaction models:hard sphere interaction&screened Coulomb *** types of interaction separate DC sputtering from HIPIMS.

关键词： DC sputtering MAX-phases mean free path particle in cell Monte Carlo collisions Monte Carlo Markov chain

Fourth-Order Splitting Methods for Time-Dependant Differential Equations

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Numerical Mathematics(Theory,Methods and Applications) 2008年第3期1卷 321-339页

作者： Jürgen geiser Department of Mathematics Humboldt-Universitt zu BerlinUnter den Linden 6D-10099 BerlinGermany.

This study was suggested by previous work on the simulation of evolution equations with scale-dependent processes,e.g.,wave-propagation or heat-transfer,that are modeled by wave equations or heat ***,we study both parabolic and hyperbolic *** focus on ADI (alternating direction implicit) methods and LOD (locally one-dimensional) methods,which are standard splitting methods of lower order,*** aim is to develop higher-order ADI methods,which are performed by Richardson extrapolation,Crank-Nicolson methods and higher-order LOD methods,based on locally higher-order *** discuss the new theoretical results of the stability and consistency of the ADI *** main idea is to apply a higher- order time discretization and combine it with the ADI *** also discuss the dis- cretization and splitting methods for first-order and second-order evolution equations. The stability analysis is given for the ADI method for first-order time derivatives and for the LOD (locally one-dimensional) methods for second-order time *** higher-order methods are unconditionally *** numerical experiments verify our results.

关键词：偏微分方程算子分裂进化方程 LOD 稳定性分析

Responding to the weather:energy budgeting by a small mammal in the wild

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Current Zoology 2020年第1期66卷 15-20页

作者： Taylor HUME Fritz geiser Shannon E.CURRIE Gerhard KORTNER Clare STAWSKI Centre for Behavioural and Physiological Ecology ZoologyUniversity of New EnglandArmidaleNSW2351Australia Leibniz Institute for Zoo and Wildlife Research Alfred-Kowalke-Str.17Berlin10315Germany Department of Biology Norwegian University of Science and TechnologyTrondheim7491Norway

Energy conservation is paramount for small mammals because of their small size,large surface area to volume ratio,and the resultant high heat loss to the *** survive on limited food resources and to fuel their expensive metabolism during activity,many small mammals employ daily torpor to reduce energy expenditure during the rest *** hypothesized that a small terrestrial semelparous marsupial,the brown antechinus Antechinus stuartii,would maximize activity when foraging conditions were favorable to gain fat reserves before their intense breeding period,but would increase torpor use when conditions were poor to conserve these fat *** antechinus were trapped and implanted with small temperature-sensitive radio transmitters to record body temperature and to quantify torpor expression and activity patterns in the *** antechinus used torpor at least once per day over the entire study *** daily torpor use increased and mean daily body temperature decreased significantly with a reduction in minimum ambient ***,antechinus employed less torpor on days with more rain and decreasing barometric *** contrast to torpor expression,activity was directly related to ambient temperature and inversely related to barometric *** results reveal that antechinus use a flexible combination of physiology and behavior that can be adjusted to manage their energy budget according to weather variables.

关键词： antechinus heterothermy marsupial semelparous temperature torpor

The effect of bacterial challenge on ferritin regulation in the yellow fever mosquito, Aedes aegypti

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Insect Science 2013年第5期20卷 601-619页

作者： Dawn L. geiser Guoli Zhou Jonathan J. Mayo Joy J. Winzerling Department of Nutritional Sciences College of Agriculture and Life Sciences the University of Arizona Tucson Arizona 85721 USA

Secreted ferritin is the major iron storage and transport protein in insects. Here, we characterize the message and protein expression profiles of yellow fever mosquito （Aedes aegypti） ferritin heavy chain homologue （HCH） and light chain homologue （LCH） subunits in response to iron and bacterial challenge. In vivo experiments demonstrated tissue-specific regulation of HCH and LCH expression over time post-blood meal （PBM）. Transcriptional regulation of HCH and LCH was treatment specific, with differences in regulation for na？ve versus mosquitoes challenged with heat-killed bacteria （HKB）. Translational regulation by iron regulatory protein （IRP） binding activity for the iron-responsive element （IRE） was tissue-specific and time-dependent PBM. However, mosquitoes challenged with HKB showed little change in IRP/IRE binding activity compared to na？ve animals. The changes in ferritin regulation and expression in vivo were confirmed with in vitro studies. We challenged mosquitoes with HKB followed by a blood meal to determine the effects on ferritin expression, and demonstrate a synergistic, time-dependent regulation of expression for HCH and LCH.

关键词： Aedes aegypti bacteria ferritin iron IRP mosquito

Operator Splitting Method for Coupled Problems:Transport and Maxwell Equations

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American Journal of Computational Mathematics 2011年第3期1卷 163-175页

作者： Jürgen geiser 不详

In this article a new approach is considered for implementing operator splitting methods for transport problems, influenced by electric fields. Our motivation came to model PE-CVD (plasma-enhanced chemical vapor deposition) processes, means the flow of species to a gas-phase, which are influenced by an electric field. Such a field we can model by wave equations. The main contributions are to improve the standard discretization schemes of each part of the coupling equation. So we discuss an improvement with implicit Runge- Kutta methods instead of the Yee’s algorithm. Further we balance the solver method between the Maxwell and Transport equation.

关键词： Operator Splitting Method Initial Value Problems Iterative Solver Method Stability Analysis Beam Propagation Methods Transport and Maxwell Equations

Using highly conserved low—copy nuclear genes to reconstruct well-resolved phylogenies of animals,fungi,plants and highly divergent eukaryotes

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Using highly conserved low—copy nuclear genes to reconstruc...

A miniaturized system for measurement of the refractive index of sub-microliter liquid

后植物志时代的系统与进化植物学——2011年全国系统与...

作者： David geiser Department of Plant Pathology the Pennsylvania State UniversityUniversity ParkPennsylvania 16802USA

A comprehensive and reliable eukaryotic tree of life is important for many aspects of biological studies from comparative developmental and physiological analyses to translational medicine and *** gene-rich and taxon-rich approaches are effective strategies to improve phylogenetic accuracy and are greatly facilitated by marker genes that are universally distributed,well conserved and orthologous across *** have identified over 900 genes useful for phylogenomic studies and show that these genes can robustly resolve the eukaryotic phylogeny,even for difficult deep eukaryotic *** addition,we demonstrate that a smaller subset(0) of these genes could resolve controversial relationships among widely divergent taxa and at various depths in the eukaryotic tree of life, providing strong support for difficult relationships such as the monophyly and branching order of some eukaryotic *** supergroups,these marker genes resulted in fungal phylogenies that are congruent with previous phylogenies,with Microsporidia as sister to *** animals,we found high supports for both deep level branching patterns such as the monophyly of Protostomia and Ecdysozoa,and specific hypotheses for rooting the placental *** genes could be obtained from both plants and fungi through PCR with degenerate primers,and facilitated construction of highly supported phylogenies with resolved relationships among *** the well-supported angiosperm relationships are well-known major groups such as monophyly of eudicots,monocots,magnoliids,and many ordinal clades, as well as the placement of Amborellales,Nymphaeales,and Austrobaileyales as successive sister groups of other flowering *** sequence comparison among angiosperms indicates that these genes contain more informative sites than the commonly used chloroplast genes,and that closely related species still show sequence divergence in some coding regions and in *** are

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Chinese Optics Letters 2019年第4期17卷 47-51页

作者：陈明惠贾文宇何锦涛 Martial geiser 郑刚 Institute of Biomedical Optics and Optometry Shanghai Institute for Minimally Invasive Therapy University of Shanghai for Science and Technology Shanghai 200093 China Beckman Laser Institute and Center for Biomedical Engineering University of California Irvine CA 92612 USA Systems Engineering Institute University of Applied Sciences Western SwitzerlandSion 1950 Switzerland

This study introduced the research and development of a portable and miniaturized system for the measurement of the refractive index of sub-microliter liquid based on a microfluidic chip. A technical method of double-beam interference, was proposed for use in the measurement. Based on this, by using a laser diode as a light source,changes in the refractive index were calculated by utilizing a complementary metal–oxide–semiconductor to detect the movement of interference fringes of the liquid. Firstly, this study simulated the effects of influencing factors on the interference infringes of two Gaussian beams, such as their spot sizes, distance between two beam spots, and detection range. Secondly, this research introduced the system design and construction of the doublebeam interference method and analyzed the results of refractive index tests on sub-microliter aqueous glucose solutions with different concentrations. The measurement accuracy reached 10^(-4) refractive index units. This system has a compact structure and is rendered portable by using batteries for its power supply. The entire system is designed to be a double Z-shaped structure with a length of about 15 cm, a width of 5 cm, and a height of about 10 cm. It can be used to measure changes in the refractive index of sub-microliter to nanoliter liquids based on the use of a microfluidic chip.

关键词： introduced the research miniaturized system sub-microliter