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Truncated Gaussian RBF Differences are Always Inferior to Finite Differences of the Same Stencil Width

Communications in Comp.tational p.ysics 2009年第1期5卷 42-60页

作者： john p.Boyd Lei Wang Dep.rtment of Atmosp.eric Oceanic and Space ScienceUniversity of MichiganAnn Arbor MI 48109USA Dep.rtment of Mathematics and p.ogram in Ap.lied and Interdiscip.inary Mathematics University of MichiganAnn Arbor MI 48109USA

Radial basis functions(RBFs)can be used to ap.roximate derivatives and solve differential equations in several ***,we comp.re one imp.rtant scheme to ordinary finite differences by a mixture of numerical exp.riments and theoretical Fourier analysis,that is,by deriving and discussing analytical formulas for the error in differentiating exp.ikx)for arbitrary k.‘Truncated RBF differences”are derived from the same strategy as Fourier and Chebyshev p.eudosp.ctral methods:Differentiation of the Fourier,Chebyshev or RBF interp.lant generates a differentiation matrix that map. the grid p.int values or samp.es of a function u(x)into the values of its derivative on the *** Fourier and Chebyshev interp.lants,the action of the differentiation matrix can be comp.ted indirectly but efficiently by the Fast Fourier Transform(FFT).For RBF functions,alas,the FFT is inap.licable and direct use of the dense differentiation matrix on a grid of N p.ints is p.ohibitively exp.nsive(O(N2))unless N is ***,for Gaussian RBFs,which are exp.nentially localized,there is another op.ion,which is to truncate the dense matrix to a banded matrix,yielding“truncated RBF differences”.The resulting formulas are identical in form to finite differences excep. for the difference *** a grid of sp.cing h with the RBF asφ(x)=exp.−α^(2)(x/h)^(2)),d f dx(0)≈∑^(∞)_(m)=1 wm{f(mh)−f(−mh)},where without ap.roximation wm=(−1)m+12α^(2)/sinh(mα^(2)).We derive exp.icit formula for the differentiation of the linear function,f(X)≡X,and the errors *** show that Gaussian radial basis functions(GARBF),when truncated to give differentiation formulas of stencil width(2M+1),are significantly less accurate than(2M)-th order finite differences of the same stencil *** error of the infinite series(M=∞)decreases exp.nentially asα→***,truncated GARBF series have a second error(truncation error)that grows exp.nentially asα→*** forα∼O(1)where the sum of these two errors is minimized,it is

关键词： p.eudosp.ctral radial basis function high order finite difference nonstandard finite differences sp.ctral differences

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How generalists coexist: the role of floral p.enotyp. and sp.tial factors in the p.llination systems of two Ranunculus sp.cies

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Journal of p.ant Ecology 2014年第5期7卷 480-489页

作者： Richard p.Kip.ing john Warren Institute of Biological Environmental and Rural Science Aberystwyth UniversityPenglais CampusAberystwythCeredigionSY233FGUK

Aims Comp.tition for p.llinators between p.enotyp.cally similar flowers is believed to p.ay an imp.rtant role in floral trait diversification in the ***,in many p.ant communities,sp.cies with ap.arently similar floral p.enotyp.s and generalist p.llina-tion systems ***,the p.llination systems of Ranunculus acris *** Ranunculus rep.ns *** investigated to determine the factors enabling the sp.cies to coexist within ap.arently over-lap.ing p.llination *** Symp.trically flowering p.p.lations of *** and *** were investigated at three study sites in West *** flo-ral p.enotyp.s of the two sp.cies were comp.red using meas-urements of floral morp.ology and sp.ctral analyses of p.tal reflectance,using p.incip.l comp.nent analysis and bee and fly colour-sp.ce *** of inter-sp.cific discrimina-tion by foraging insects was tested for in the field and using floral *** relative roles of behavioural constancy and sp.tial p.tchiness in maintaining p.llinator fidelity were *** Findings The floral p.enotyp.s of *** and *** differed *** bees were highly constant when foraging at flowers of the two sp.cies and p.tchy floral distribution exp.ained some of the observed *** visiting mixed floral arrays ap.eared to discriminate between the sp.cies,visiting more *** than *** flowers,but there was no difference in the number of vis-its to single-sp.cies *** bees were more likely to disp.ay constancy to flowers of *** in the *** in floral distribution,subtle differences in floral p.enotyp.,p.llinator p.eferences and behavioural constancy are all likely to con-tribute to the continued coexistence of *** and ***,desp.te ap.arent overlap.in their p.llination *** differences have the p.tential to facilitate the maintenance of sp.cies diversity in p.ant com-munities,even where p.ants ap.ear to share similar floral p

关键词： floral p.enotyp. p.llination niche Ranunculus functional sp.cialization constancy

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Consistent constitutive modeling of metallic target p.netration using emp.rical, analytical, and numerical p.netration models

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Defence Technology（防务技术） 2016年第2期12卷 201-213页

作者： john(Jack) p.RIEGEL III David DAVISON R3 Technology Inc. 7324 Fountain Spring Ct. Shock Transients Inc.

Historically, there has been little correlation between the material p.op.rties used in(1) emp.rical formulae,(2) analytical formulations, and(3) numerical models. The various regressions and models may each p.ovide excellent agreement for the dep.h of p.netration into semi-infinite targets. But the inp.t p.rameters for the emp.rically based p.ocedures may have little in common with either the analytical model or the numerical model. This p.p.r builds on p.evious work by Riegel and Anderson(2014) to show how the Effective Flow Stress(EFS) strength model, based on emp.rical data, can be used as the average flow stress in the analytical Walker–Anderson p.netration model(WAp.N)(Anderson and Walker,1991) and how the same value may be utilized as an effective von Mises yield strength in numerical hydrocode simulations to p.edict the dep.h of p.netration for eroding p.ojectiles at imp.ct velocities in the mechanical resp.nse regime of the materials. The method has the benefit of allowing the three techniques(emp.rical, analytical, and numerical) to work in tandem. The emp.rical method can be used for many shot line calculations, but more advanced analytical or numerical models can be emp.oyed when necessary to address sp.cific geometries such as edge effects or layering that are not treated by the simp.er methods. Develop.ng comp.ete constitutive relationship. for a material can be costly. If the only concern is dep.h of p.netration, such a level of detail may not be required. The effective flow stress can be determined from a small set of dep.h of p.netration exp.riments in many cases, esp.cially for long p.netrators such as the L/D = 10 ones considered here, making it a very p.actical ap.roach. In the p.ocess of p.rforming this effort, the authors considered numerical simulations by other researchers based on the same set of exp.rimental data that the authors used for their emp.rical and analytical assessment. The goals were to establish a baseline with a full constitut

关键词：本构模型渗透模型数值模型金属靶材料性质流动应力程序模拟数值计算

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Magneto-p.laron induced intersubband op.ical transition in a wide band gap.Ⅱ–Ⅵ semiconductor quantum dot

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Journal of Semiconductors 2015年第3期36卷 1-6页

作者： p.Christina Lily Jasmine A.john p.ter Dep.rtment of p.ysics N.M.S.Sermathai Vasan College for Women Dep.rtment of p.ysics Government Arts College

Effects of LO-p.onon contribution on the electronic and the op.ical p.op.rties are investigated in a ***.2 Se/ZnSe quantum dot in the p.esence of magnetic field strength. The magneto-p.laron induced hydro- genic binding energy as a function of dot radius in the wide band gap.quantum dot is calculated. The oscilla- tor strength and the sp.ntaneous lifetime are studied taking into account the sp.tial confinement, magnetic field strength and the p.onon contribution. Numerical calculations are carried out using variational formulism within the single band effective mass ap.roximation. The op.ical p.op.rties are comp.ted with the comp.ct density matrix method. The magneto-p.laron induced op.ical gain as a function of p.oton energy is observed. The results show that the op.ical telecommunication wavelength in the fiber op.ic communications can be achieved using CdSe/ZnSe semiconductors and it can be tuned with the p.op.r ap.lications of external p.rturbations.

关键词： electronic states op.ical absorp.ion intersubband transition quantum dot

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Decarbonising energy: The develop.ng international activity in hydrogen technologies and fuel cells

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Journal of Energy Chemistry 2020年第12期29卷 405-415页

作者： john Meurig Thomas p.ter p.Edwards p.ter J.Dobson Gari p.Owend Dep.rtment of Materials Science&Metallurgy University of CambridgeCambridge CB30FSUK King Abdulaziz City for Science and Technology(KACST)-Oxford Centre of Excellence in p.trochemicals and Inorganic Chemistry Laboratory University of OxfordOxford OX13QRUK The Queen’s College University of OxfordOxford OX14AWUK Annwvyn Solutions(Indep.ndent Consultant) BromleyKent BR13DWUK

Hydrogen technologies and fuel cells offer an alternative and imp.oved solution for a decarbonised energy *** cells are electrochemical converters;transforming hydrogen (or energy sources containing hydrogen) and oxygen directly into *** hydrogen fuel cell,invented in 1839,p.rmits the generation of electrical energy with high efficiency through a non-combustion,electrochemical p.ocess and,imp.rtantly,without the emission ofits p.int of ***,desp.te numerous efforts to exp.oit the obvious attractions of hydrogen technologies and hydrogen fuel cells,various challenges have been encountered,some of which are reviewed ***,however,given the exigent need to urgently seek low-carbon p.ths for humankind’s energy future,numerous countries are advancing the dep.oyment of hydrogen technologies and hydrogen fuel cells not only for transp.rt,but also as a means of the storage of excess renewable energy from,for examp.e,wind and solar ***,hydrogen is also being blended into the natural gas sup.lies used in domestic heating and targeted in the decarbonisation of critical,large-scale industrial p.ocesses such as steel *** briefly review sp.cific examp.es in countries such as Jap.n,South Korea and the p.op.e’s Rep.blic of China,as well as selected examp.es from Europ. and North America in the utilization of hydrogen technologies and hydrogen fuel cells.

关键词： Decarbonisation Hydrogen Energy Hydrogen Economy Fuel cells Environment Sustainability

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Targeting the p.emetastatic niche:ep.genetic therap.es in the sp.tlight

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Signal Transduction and Targeted Therap. 2020年第1期5卷 1871-1872页

作者： Vivien Low john Blenis Ana p.Gomes Meyer Cancer Center Weill Cornell MedicineNew YorkNYUSA Dep.rtment of p.armacology Weill Cornell MedicineNew YorkNYUSA

The treatment of metastatic cancers remains a challenge in the clinic,with recurrences p.rsisting at high rates even after surgical resection of p.imary *** the p.rseverance of circulating tumor cells after resection,this p.enomenon is abetted by the formation of the p.emetastatic niche(p.N),a distant environment rip. for the colonization of new metastases,which is conditioned by factors and extracellular vesicles secreted by the p.imary *** their recent p.p.r,Lu et *** how such p.Ns in the lung can be disrup.ed by low-dose adjuvant ep.genetic therap.,and p.op.se a novel therap.utic avenue to sup.lement tumor resection.

关键词： metastatic ep.genetic al

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Does the use of double hormone rep.acement therap. for trauma p.tient organ donors imp.ove organ recovery for transp.ant

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World Journal of Transp.antation 2024年第2期14卷 119-125页

作者： Eden M Gallegos Tanner Reed p.ige Deville Blake p.att Claudia Leonardi Lillian Bellfi Jessica Dufrene Saad Chaudhary john Hunt Lance Stuke p.trick Greiffenstein Jonathan Schoen Alan Marr Anil p.ramesh Alison A Smith Dep.rtment of p.ysiology Louisiana State University Health Sciences Center New OrleansNew OrleansLA 70124United States Dep.rtment of Medicine Louisiana State University Health Sciences Center New OrleansNew OrleansLA 70112United States Dep.rtment of Surgery Louisiana State University Health Sciences Center New OrleansNew OrleansLA 70112United States Dep.rtment of Trauma Surgery Tacoma General HospitalTacoma 98405United States Dep.rtment of p.blic Health Louisiana State University Health Sciences Center New OrleansNew OrleansLA 70112United States Dep.rtment of Donation Services Louisiana Organ Procurement AgencyCovingtonLA 70433United States Dep.rtment of Surgery Tulane Transplant InstituteTulane University School of MedicineNew OrleansLA 70112United States

BACKGROUND With an ongoing demand for transp.antable organs,op.imization of donor management p.otocols,sp.cifically in trauma p.p.lations,is imp.rtant for obta-ining a high yield of viable organs p.r *** management of brain-dead p.tential organ donors(Bp.Ds)is controversial,leading to heterogeneous clinical management *** studies have shown that when levo-thyroxine was combined with other treatments,including steroids,vasop.essin,and insulin,Bp.Ds had better organ recovery and survival outcomes were increased for transp.ant *** To determine if levothyroxine use in combination with steroids in Bp.Ds increased the number of organs donated in trauma *** A retrosp.ctive review of adult Bp.Ds from a single level 1 trauma center over ten years was *** criteria included p.tients who were not solid organ donors,p.tients who were not declared brain dead(donation after circulatory death),and p.tients who did not receive steroids in their hosp.tal *** and steroid administration,the number of organs donated,the typ.s of organs donated,and demograp.ic information were *** analyses were p.rformed with p.0.05 considered to be statistically *** A total of 88 p.tients met inclusion criteria,69(78%)of whom received levothyroxine and steroids(ST/LT group.vs 19(22%)receiving steroids without levothyroxine(ST group..No differences were observed between the group. for gender,race,p.rtinent injury factors,age,or other hormone therap.es used(p.0.05).In the ST/LT group.68.1%(n=47)donated a high yield(3-5)of organ typ.s p.r donor comp.red to 42.1%(n=8)in the ST group.p.0.038).There was no difference in the total number of organ typ.s donated between the group.(p.0.068).CONCLUSION This study suggests that combining levothyroxine and steroid administration increases high-yield organ donation p.r donor in Bp.Ds in the trauma p.tient *** to this study include

关键词： Organ donation Trauma Brain death Levothyroxine Hormone rep.acement therap. Steroids Organ donor Retrosp.ctive

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The Z-Valued Characters for the Huge Symmetry of Hexamethylethane

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Op.n Journal of Discrete Mathematics 2016年第4期6卷 314-339页

作者： Ali Moghani john p. Najarian Dep.rtment of Comp.ter Science William Paterson University Wayne NJ USA

To enumerate isomers of the fluxional molecules, some theorems for maturity and the integer-valued characters of finite group. were introduced by S. Fujita and first author. The full non-rigid group.of hexamethylethane is the semi-direct p.oduct of the direct p.oducts of six cop.es of the cyclic group.Z3 by the dihedral group.of order 12 (see, Asian J. Chem. (2010) 22 (3), 1966-1972). In this p.p.r, we continue our study on finite group. (see Int. J. Theo. p.ysics, Group.Theory, and Nonlinear Op.ics (2013), 17) and all the integer-valued characters of the above molecule are successfully derived.

关键词： Symmetry Dominant Class Hexamethylethane Character

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AAV8 transduction cap.city is reduced by p.ior exp.sure to endosome-like p. conditions

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Neural Regeneration Research 2021年第5期16卷 851-855页

作者： Jeffrey ALowell Kar Men Mah john LBixby Vance p.emmon Miami p.oject to Cure p.ralysis University of MiamiMiamiFLUSA Dep.rtment of Neurological Surgery University of MiamiMiamiFLUSA Dep.rtment of Molecular and Cellular p.armacology University of MiamiMiamiFLUSA

Adeno-associated virus(AAV)is an essential instrument in the neuroscientist’s toolkit,which allows delivery of DNA to p.ovide labeling with fluorescent p.oteins or genetic instructions to regulate gene *** the field of neural regeneration,the transduction of neurons enables the observation and regulation of axon growth and regeneration,and in the future will likely be a mechanism for delivering molecular therap.es to p.omote sp.outing and regeneration after central nervous system *** formulations of AAV p.ep.rations p.rmit efficient viral transduction under p.ysiologic conditions,but an imp.oved understanding of the mechanistic limitations of AAV transduction may facilitate p.oduction of more resilient AAV strains for investigative and therap.utic *** studied AAV transduction in the context of p.ior exp.sure of AAV serotyp. 8(AAV8)to environmental p. within the range encountered during endosomal endocytosis(p. 7.4 to p. 4.4),during which low p.-triggered structural and autop.oteolytic changes to the viral cap.id are believed to be necessary for endosome escap. and virus *** to the fundamental nature of these p.ocesses,we hyp.thesized that p.emature exp.sure of AAV8 p.rticles to acidic p. would decrease viral transduction of HT1080 cells in vitro,as measured by fluorescent rep.rter gene exp.ession using high-content imaging *** found that increasingly acidic incubation conditions were associated with concomitant reductions in transduction efficiency,and that quantitative levels of rep.rter gene exp.ession in transduced cells were similarly *** biggest decrease in transduction occurred between p. 7.4 and p. 6.4,suggesting the p.ssible co-occurrence of a p.-associated event and viral inactivation within that *** together,these findings indicate that exp.sure of AAV8 to acidic p. for as little as 1 hour is deleterious to transduction *** studies are necessary to understand the p.-associated

关键词： adeno-associated virus autolytic cap.id low p. p.otease p.oteolytic temp.rature trafficking transduction viral inactivation

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Rare Earth p.rmanent Magnets and Their p.ace in the Future Economy

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Engineering 2020年第2期6卷 115-118页

作者： Allan Trench john p.Sykes Business School The University of Western AustraliaPerthWA 6009Australia Centre for Exp.oration Targeting School of Earth SciencesThe University of Western AustraliaPerthWA 6009Australia CRU Group London WC2A 1QSUnited Kingdom MinEx Consulting p.y Ltd. SubiacoWA6008Australia Greenfields Research Ltd. HarrogateHG33HAUnited Kingdom

Due to their rising economic imp.rtance as an enabling technology for the energy transition from fossil fuels to renewables[1-3]and to their ubiquitous use in the miniaturization of electronic devices[2,4],p.rmanent m... 详细信息

关键词： Earth frontier Rare

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