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Simulation of Impurity Diffusion in a Strained Nanowire Using Off-Lattice KMC

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Communications in Computational Physics 2007年第1期2卷 164-176页

作者： Weidong Guo tim P.Schulze Weinan e Department of Mathematics University of TennesseeKnoxvilleTN 37996-1300USA Department of Mathematics and Program in Applied and Computational Mathematics Princeton UniversityPrincetonNJ 08544-1000USA.

Kinetic Monte Carlo(KMC)is a stochastic model used to simulate crystal ***,most KMC models rely on a pre-defined lattice that neglects dislocations,lattice mismatch and strain *** this paper,we investigate the use of a 3D off-lattice KMC *** test this method by investigating impurity diffusion in a strained FCC *** faster than a molecular dynamics simulation,the most general implementation of off-lattice KMC is much slower than a lattice-based *** improved procedure is achieved for weakly strained systems by precomputing approximate saddle point locations based on unstrained lattice *** this way,one gives up some of the flexibility of the general method to restore some of the computational speed of lattice-based *** addition to providing an alternative approach to nano-materials simulation,this type of simulation will be useful for testing and calibrating methods that seek to parameterize the variation in the transition rates for lattice-based KMC using continuum modeling.

关键词： Off-lattice KMC nanowire strain rate impurity diffusion.

The Flemish Performance-based Research Funding System: A Unique Variant of the Norwegian Model

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Journal of Data and Information Science 2018年第4期3卷 45-60页

作者： tim C.e.engels Raf Guns Centre for R&D Monitoring (eCOOM) Faculty of Social Science University of Antwerp

The BOF-key is the performance-based research funding system that is used in Flanders, Belgium. In this paper we describe the historical background of the system, its current design and organization, as well as its effects on the Flemish higher education landscape. The BOFkey in its current form relies on three bibliometric parameters: publications in Web of Science, citations in Web of Science, and publications in a comprehensive regional database for SSH publications. Taken together, the BOF-key forms a unique variant of the Norwegian model: while the system to a large extent relies on a commercial database, it avoids the problem of inadequate coverage of the SSH. Because the bibliometric parameters of the BOF-key are reused in other funding allocation schemes, their overall importance to the Flemish universities is substantial.

关键词： Performance-based research funding systems Flanders(Belgium) Norwegian model Web of Science VABB-SHW

Solvable base change and Rankin-Selberg convolutions

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Science China Mathematics 2017年第1期60卷 99-112页

作者： GILLeSPIe tim Department of Mathematics St. Ambrose University Davenport IA 52803 USA

Let π and π′ be unitary automorphic cuspidal representations of GL_n(A_e) and GL_m(A_F), and let e and F be solvable Galois extensions of Q of degrees ? and ?′, respectively. Using the fact that the automorphic induction and base change maps exist for e and F, and assuming an invariance condition under the actions of the Galois groups, we attach to the pair(π, π′) a Rankin-Selberg L-function L(s, π×e,Fπ′) for which we prove a prime number theorem. This gives a method for comparing two representations that could be defined over completely different extensions, and the main results give a measure of how many cuspidal components the two representations π and π′ have in common when automorphically induced down to the rational numbers. The proof uses the structure of the Galois group of the composite extension eF and the character groups attached to the fields via class field theory. The second main theorem also gives an indication of when the base change of π up to the composite extension eF remains cuspidal.

关键词： automorphic L-function base change automorphic induction

KT Boundary Chromites Determined to be Terrestrial:Cr Isotopic evidence for excavation and ejection of Mafic/Ultramafic Rocks by the KT Boundary Impact

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Acta Geologica Sinica(english edition) 2017年第S1期91卷 26-27页

作者： Peter OLDS Mathew e.SANBORN tim TeAGUe YIN Qingzhu College of Alameda University of California at Davis University of California at Berkeley

evidence for a mantle and/or basaltic component in KT boundary distal ejecta is apparently inconsistent with ejection from Chicxulub Crater since it is located on;5km thick continental crust（De Paolo et al.,1983;Montanari et al.,1983;Hildebrand and Boynton,1988,1990）.evidence for mafic/ultramafic target rocks was reinforced by discovery of chromites,some with shock planar deformation features（PDF）,in impact layer samples from sites in southern Colorado and eastern Wyoming（Bohor et al.,1990）.However,until now it was unclear whether the chromites originated with an impactor or with terrestrial target *** this end,high-precision 54Cr/52Cr isotope ratios were measured on KT boundary chromites along with known terrestrial *** find a terrestrial 54Cr/52Cr ratio in KT boundary chromites from impact layer samples collected at the above sites over the last several years（Fig.1）.ejected terrestrial chromites suggest the impact sampled terrestrial mafic and/or ultramafic target rocks not known to exist in the Chicxulub target area.

关键词： KT Boundary Chromites Determined to be Terrestrial Cr Isotopic evidence for excavation and ejection of Mafic/Ultramafic Rocks by the KT Boundary Impact

Understorey species distinguish late successional and ancient forests after decades of minimum human intervention: A case study from Slovenia

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Forest ecosystems 2023年第1期10卷 92-101页

作者： Mirjana Sipek tim Ravnjak Nina Sajna University of Maribor Faculty of Natural Sciences and MathematicsKoroska c.1602000MariborSlovenia

The main species composition drivers in temperate deciduous forests are environmental conditions, a stand?s age and the site history, e.g., the succession stage and past land use, as well as disturbance regime and current management. We compared plant species diversity and composition in late successional and ancient forests, cooccurring on the same small river island applying species accumulation curves and nonmetric multidimensional scaling, respectively. Given the island?s geomorphological characteristics, we expected these to be very similar before human intervention in the past. The forests experienced differing disturbance regimes in the past, while over the last 30 years, human intervention has been the same and reduced to a minimum. The ancient forest in this study had two major characteristics defining it as old, mature forest: continuity of presence for more than 200years and specific composition. The late successional forest experienced major disturbance in the 20th century and was allowed natural regeneration by bordering on the ancient forest, representing a potential species pool,and by decades of minimum human intervention. Our results showed that, even though there was no difference in species richness, we could still detect differences between the forests, particularly in the abundance and species composition of the understorey, among which geophytes had the most indicative importance. To make our results useful on a broader scale, we composed from the literature a species list of plants indicative for ancient forest and tested its application. These results are important for distinguishing between old and mature secondary stands and particularly for identifying old forest stands, which should be conserved and, in the case of fragmented landscapes, included in a network connecting forest fragments.

关键词： Forest community Successional forest Indicator plants Plant diversity Understorey Geophytes

Prime number theorems for Rankin-Selberg L-functions over number fields

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Science China Mathematics 2011年第1期54卷 35-46页

作者： GILLeSPIe tim JI GuangHua Department of Mathematics The University of Iowa Iowa City Iowa 52242 USA School of Mathematics Shandong University Jinan 250100 China

In this paper we define a Rankin-Selberg L-function attached to automorphic cuspidal represen-tations of GLm(Ae) × GLm (AF ) over cyclic algebraic number fields e and F which are invariant under the Galois action,by ... 详细信息

关键词： Rankin-Selberg L-functions prime number theorem base change

Laser induced oxidation and optical properties of stoichiometric and non-stoichiometric Bi2Te3 nanoplates

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Nano Research 2015年第3期8卷 851-859页

作者： Rui He Sukrit Sucharitakul Zhipeng Ye Courtney Keiser tim e. Kidd Xuan P. A. Gao Department of Physics University of Northern Iowa Cedar Falls Iowa 50614 USA Department of Physics Case Western Reserve University Cleveland Ohio 44106 USA

Bi-Te nanoplates （NPs） grown by a low pressure vapor transport method have been studied by Raman spectroscopy, atomic force microscopy （AFM）, energy- dispersive X-ray spectroscopy （eDS）, and Auger electron spectroscopy （AeS）. We find that the surface of relatively thick （more than tens of nanometers） Bi2Te3 NPs is oxidized in the air and forms a bump under heating with moderate laser power, as revealed by the emergence of Raman lines characteristic of Bi2O3 and TeO2 and characterization by AFM and eDS. Further increase of laser power burns holes on the surface of the NPs. Thin （thicknesses less than 20 nm） NPs with stoichiometry different from Bi2Te3 were also studied. Raman lines from non-stoichiometric NPs are different from those of stoichiometric ones and display characteristic changes with the increase of Bi concentration. Thin NPs with the same thickness but different stoichiometries show different color contrast compared to the substrate in the optical image. This indicates that the optical absorption coefficient in thin Bi-Te NPs strongly depends on their stoichiometry.

关键词： bismuth telluride nanoplate Raman spectroscopy oxidation stoichiometry

Impact of 10-60-Day Low-Frequency Steering Flows on Straight Northward-Moving Typhoon Tracks over the Western North Pacific

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Journal of Meteorological Research 2018年第3期32卷 394-409页

作者： Qiao LIU tim LI Weican ZHOU Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environmental ChangeCollaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology International Pacific Research Center and Department of Atmospheric Sciences School of Ocean and Earth Science and Technology University of Hawaii

This study investigates the impact of low-frequency(intraseasonal and interannual) steering flows on straight northward-moving(defined as a meridional displacement two times greater than the zonal displacement) typhoons over the western North Pacific using observational data. The year-to-year change in the northward-moving tracks is affected by the interannual change in the location and intensity of the subtropical high. A strengthened northward steering flow east of 120°e and a weakened easterly steering flow south of the subtropical high favor more frequent straight northward tracks. examining each of the individual northward-moving typhoons shows that they interact with three types of intraseasonal(10-60-day) background flows during their northward journey. The first type is the monsoon gyre pattern, in which the northward-moving typhoon is embedded in a closed cyclonic monsoon gyre circulation. The second type is the wave train pattern, where a cyclonic(anticyclonic) vorticity circulation is located to the west(east) of the northward-moving typhoon center. The third type is the mid-latitude trough pattern, in which the northward-moving typhoon center is located in the maximum vorticity region of the trough.

关键词： intraseasonal steering flow interannual steering flow straight northward-moving typhoon

Covariation between personalities and individual differences in coping with stress:Converging evidence and hypotheses

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Current Zoology 2010年第6期56卷 728-740页

作者： Claudio CAReRe Doretta CARAMASCHI tim W. FAWCeTT Dipartimento di ecologia e Sviluppo economico Sostenibile Università della Tuscia GRIP Université de Montréal 3050douard-Montpetit

In the past decade there has been a profusion of studies highlighting covariation between individual differences in stress physiology and behavioural profiles, here called personalities. Such individual differences in ways of coping with stress are relevant both in biomedicine, since different personalities may experience a different stress and disease vulnerability, and in behavioural ecology, since their adaptive value and evolutionary maintenance are the subject of debate. However, the precise way in which individual stress differences and personalities are linked is unclear. Here we provide an updated overview of this covariation across different species and taxa, consider its functional significance and present working hypotheses for how behavioural and physiological responses to stress might be causally linked, affecting life-history traits such as dispersal and life-span [Current Zoology 56 （6）： 728-740, 2010].

关键词： Animal personality Coping style Agression Stress response Corticosterone Glucocorticoids Natural selection Fitness evolution