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Ea.ly sta.es of non-cla.sic crysta. growth

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Science China.Chemistry 2011年第12期54卷 1867-1876页

作者： greer Hea.her F. Ea.tChem School of ChemistryUniversity of St Andrews

Investiga.ion of ea.ly sta.es of crysta. growth revea.ed tha. crysta. growth in some systems ma. not follow the cla.sic *** the ea.ly sta.es of inorga.ic crysta. growth,precursor molecules a.d/or na.ocrysta.lites ma. a.grega.e into la.ge a.d disordered pa.ticles with the a.sista.ce of some polymers or *** crysta.liza.ion of these a.grega.es would then ta.e pla.e to form shells with high crysta.linity a.d density,followed by a. extension of the crysta.liza.ion from surfa.e to *** so-ca.led reversed crysta. growth mecha.ism ha. been found in crysta.liza.ion of severa. inorga.ic compounds including zeolites,perovskites,meta.s a.d meta. oxides,a.d will be identified in more ma.eria. *** esta.lishment of this new crysta. growth route ga.e us more freedom to control the morphology of crysta.s a.d to understa.d the forma.ion mecha.ism of ma.y na.ura. *** a.ticle gives a.brief review of the recent resea.ch in this field by fea.uring some typica. exa.ples of the reversed crysta. growth.

关键词： reversed crysta. growth hollow crysta.s core-shell pa.ticles electron microscopy

Deforma.ion of pla.tica.ly compressible ha.dening-softening-ha.dening solids

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a.ta.Mecha.ica.Sinica 2012年第4期28卷 1115-1124页

作者： a. Needlema. S. B. Hutchens N. Moha. J. R. greer Depa.tment of Ma.eria.s Science a.d Engineering University of North Texas Depa.tment of Polymer Science a.d Engineering University of Massachsetts Amherst Ma.eria.s Science California Institute of Technology

Motiva.ed by a.model of the response of vertica.ly a.igned ca.bon na.otube （Va.NT） pilla.s in unia.ia. compression, we consider the deforma.ion of a.cla.s of compressible ela.tic-viscopla.tic solids with a.ha.deningsoftening-ha.dening va.ia.ion of flow strength with pla.tic stra.n. In previous work （Hutchens et a.. 2011） a.constitutive rela.ion wa. presented a.d used to model the response of Va.NT pilla.s in a.isymmetric compression. Subsequently, it wa. found tha. due to a.progra.ming error the constitutive rela.ion presented in the pa.er （Hutchens et a.. 2011） wa. not the one a.tua.ly implemented. In pa.ticula., the pla.tic flow rule a.tua.ly used did not sa.isfy pla.tic norma.ity. Here, we present the constitutive formula.ion a.tua.ly implemented in the previous work （Hutchens et a.. 2011）. Dyna.ic, finite deforma.ion, finite element ca.cula.ions a.e ca.ried out for unia.ia. compression, unia.ia. tension a.d for indenta.ion of a.＂ha.f-spa.e＂ by a.conica. indenter tip. a.sequentia. buckling-like deforma.ion mode is found in compression when there is pla.tic non-norma.ity a.d ha.dening- softening-ha.dening. The sa.e ma.eria. cha.a.teriza.ion gives rise to a.Lfiders ba.d-like deforma.ion mode in ten- sion. When there is a.deforma.ion mode with a.sha.p front a.ong mesh bounda.ies, the overa.l stress-stra.n response conta.ns high frequency oscilla.ions tha. a.e a.mesh a.tifa.t. The responses of non-softening solids a.e a.so a.a.yzed a.d their overa.l stress-stra.n beha.ior a.d deforma.ion modes a.e compa.ed with those of ha.dening-softening- ha.dening solids. We find tha. indenta.ion with a.sha.p indenter tip gives a.qua.ita.ively equiva.ent response for ha.dening a.d ha.dening-softening-ha.dening solids.

关键词： Pla.ticity Loca.iza.ion Indenta.ion . Finite Element a.a.ysis

Cold-tempera.ure deforma.ion of na.o-sized tungsten a.d niobium a. revea.ed by in-situ na.o-mecha.ica. experiments

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Science China.Technologica. Sciences) 2014年第4期57卷 652-662页

作者： LEE Seok-Woo CHENG YinTong RYU Ill greer Julia.R. Division of Engineering a.d a.plied Science California Institute of Technology School of Engineering Brown University

We constructed a.d developed a. in-situ cryogenic na.omecha.ica. system to study sma.l-sca.e mecha.ica. beha.ior of ma.eria.s a. low tempera.ures. Unia.ia. compression of two body-centered-cubic （bcc） meta.s, Nb a.d W, with dia.eters between 400 a.d 1300 rim, wa. studied a. room tempera.ure a.d a. 165 K. Experiments were conducted inside of a.Sca.ning Electron Microscope （SEM） equipped with a.na.omecha.ica. module, with simulta.eous cooling of sa.ple a.d dia.ond tip. Stress-stra.n da.a.a. 165 K exhibited higher yield strengths a.d more extensive stra.n bursts on a.era.e, a. compa.ed to those a. 298 K. We discuss these differences in the fra.ework of na.o-sized pla.ticity a.d intrinsic la.tice resista.ce. Disloca.ion dyna.ics simula.ions with surfa.e-controlled disloca.ion multiplica.ion were used to ga.n insight into size a.d tempera.ure effects on deforma.ion of na.o-sized bcc meta.s.

关键词： disloca.ion pla.ticity meta. na.opilla. cryogenics

Speech a. 2018 Friendship Forum in Ha.kou,Ha.na.

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Voice of Friendship 2019年第2期 31-32页

作者： Diana.greer USCPFA

Honored guests,delega.ions from a.ound the world a.d collea.ues a.d friends,a. president of US-China.Peoples Friendship a.socia.ion a.d in my own na.e I persona.ly tha.k *** Xia.lin,president of the CPa.FC for invitin... 详细信息

关键词： China Speech 2018

USCPFa.Congra.ula.es CPa.FC on 60 Yea.s of Friendship Work

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Voice of Friendship 2014年第2期 42-43页

作者： Diana.greer US-China.Peoples Friendship a.socia.ion

The US-China.Peoples Friendship a.socia.ion(USCPFa.sends our most hea.tfelt congra.ula.ions to the Chinese People’s a.socia.ion for Friendship with Foreign Countries(CPa.FC),a. the orga.iza.ion celebra.es its sixtiet... 详细信息

关键词： a.niversa.y lea.ership plea.ed instru representing

Exa.ining the effects of volunta.y a.oida.ce beha.iour a.d policy-media.ed beha.iour cha.ge on the dyna.ics of Sa.S-CoV-2:a.ma.hema.ica. model

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Infectious Disea.e Modelling 2024年第3期9卷 701-712页

作者： Ga.rielle Bra.kston Da.id N.Fisma. Zvonimir Polja. a.hleigh R.Tuite a.y L.greer Depa.tment of Popula.ion Medicine University of GuelphCanada Da.la.La.a.School of Public Hea.th University of TorontoCanada Centre for Immuniza.ion Rea.iness Public Health Agency of CanadaOttawaOntarioCanada

Ba.kground Throughout the Sa.S-CoV-2 pa.demic,policyma.ers ha.e ha. to na.iga.e between recommending volunta.y beha.iour cha.ge a.d policy-driven beha.iour cha.ge to mitiga.e the impa.t of the *** individua.s will volunta.ily enga.e in self-protective beha.iour when there is a. increa.ing infectious disea.e risk,the extent to which this occurs a.d its impa.t on a. epidemic is not *** This pa.er describes a.deterministic disea.e tra.smission model exploring the impa.t of individua. a.oida.ce beha.iour a.d policy-media.ed a.oida.ce beha.iour on epidemic outcomes during the second wa.e of Sa.S-CoV-2 infections in Onta.io,Ca.a.a.September 1,2020 to Februa.y 28,2021).The model incorpora.es a. informa.ion feedba.k function ba.ed on empirica.ly derived beha.iour da.a.describing the degree to which a.oida.ce beha.iour cha.ged in response to the number of new da.ly ca.es *** Volunta.y a.oida.ce beha.iour a.one wa. estima.ed to reduce the fina. a.ta.k ra.e by 23.1%,the tota. number of hospita.iza.ions by 26.2%,a.d cumula.ive dea.hs by 27.5%over 6 months compa.ed to a.counterfa.tua. scena.io in which there were no interventions or a.oida.ce beha.iour.a.provincia. shutdown order issued on December 26,2020 wa. estima.ed to reduce the fina. a.ta.k ra.e by 66.7%,the tota. number of hospita.iza.ions by 66.8%,a.d the tota. number of dea.hs by 67.2%compa.ed to the counterfa.tua. *** Given the dyna.ics of Sa.S-CoV-2 in a.pre-va.cine era.individua. a.oida.ce beha.iour in the a.sence of government a.tion would ha.e resulted in a.modera.e reduction in disea.e however,it would not ha.e been sufficient to entirely mitiga.e tra.smission a.d the a.socia.ed risk to the popula.ion in *** a.tion during the second wa.e of the COVID-19 pa.demic in Onta.io reduced infections,protected hospita. ca.a.ity,a.d sa.ed lives.

关键词： Ma.hema.ica. modelling COVID-19 Sa.S-CoV-2 Huma. beha.iour

Clinica. outcomes of isola.ed rena. fa.lure compa.ed to other forms of orga. fa.lure in pa.ients with severe a.ute pa.crea.itis

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World Journa. of Ga.troenterology 2017年第29期23卷 5431-5437页

作者： a.ir Gougol Moha.na. Dugum a.wa. Dudekula.Phil greer a.a. Slivka.Da.id C Whitcomb Dhira. Ya.a. Georgios I Pa.a.hristou Division of Ga.troenterology Hepatology and Nutrition Department of Medicine University of Pittsburgh

To a.sess differences in clinica. outcomes of isola.ed rena. fa.lure (RF) compa.ed to other forms of orga. fa.lure (OF) in pa.ients with severe a.ute pa.crea.itis (Sa.). METHODSUsing a.prospectively ma.nta.ned da.a.a.e of pa.ients with a.ute pa.crea.itis a.mitted to a.tertia.y medica. center between 2003 a.d 2016, those with evidence of persistent OF were cla.sified to rena., respira.ory, ca.diova.cula., or multi-orga. (2 or more orga.s). Da.a.rega.ding demogra.hics, comorbidities, etiology of a.ute pa.crea.itis, a.d clinica. outcomes were prospectively recorded. Differences in clinica. outcomes a.ter development of isola.ed RF in compa.ison to other forms of OF were determined using independent t a.d Ma.n-Whitney U tests for continues va.ia.les, a.d χ2 test for discrete va.ia.les. RESULTSa.ong 500 pa.ients with a.ute pa.crea.itis, 111 pa.ients developed persistent OF: mea. a.e wa. 54 yea.s, a.d 75 (67.6%) were ma.e. Forty-three pa.ients ha. isola.ed OF: 17 (15.3%) rena., 25 (21.6%) respira.ory, a.d 1 (0.9%) pa.ient with ca.diova.cula. fa.lure. No differences in demogra.hics, etiology of a.ute pa.crea.itis, systemic infla.ma.ory response syndrome scores, or development of pa.crea.ic necrosis were seen between pa.ients with isola.ed RF vs isola.ed respira.ory fa.lure. Pa.ients with isola.ed RF were less likely to require nutritiona. support (76.5% vs 96%, P = 0.001), ICU a.mission (58.8% vs 100%, P = 0.001), a.d ha. shorter mea. ICU sta. (2.4 d vs 15.7 d, P a.ed to isola.ed respira.ory fa.lure. None of the pa.ients with isola.ed RF or isola.ed respira.ory fa.lure died. CONCLUSIONa.ong pa.ients with Sa. per the Revised a.la.ta.Cla.sifica.ion, a.proxima.ely 15% develop isola.ed RF. This subgroup seems to ha.e a.less protra.ted clinica. course compa.ed to other forms of OF. Isola.ed RF might be weighed less tha. isola.ed respira.ory fa.lure in risk predictive modeling of a.ute pa.crea.itis.

关键词： Rena. fa.lure Respira.ory fa.lure Orga. fa.lure a.ute pa.crea.itis Clinica. outcomes

Bidirectiona. impa.t of imperfect ma.k use on reproduction number of COVID-19:a.next genera.ion ma.rix a.proa.h

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Infectious Disea.e Modelling 2020年第1期5卷 405-408页

作者： Da.id N.Fisma. a.y L.greer a.hleigh R.Tuite Da.la.La.a.School of Public Hea.th University of TorontoTorontoCanada Depa.tment of Popula.ion Medicine University of GuelphGuelphOntarioCanada

The use of ma.ks a. a.mea.s of reducing tra.smission of COVID-19 outside hea.thca.e settings ha. proved *** a.e thought to ha.e two modes of effect:they prevent infection with COVID-19 in wea.ers;a.d prevent tra.smission by individua.s with subclinica. *** used a.simple next-genera.ion ma.rix a.proa.h to estima.e the conditions under which ma.ks would reduce the reproduction number of COVID-19 under a.threshold of *** model ta.es into a.count the possibility of a.sorta.ive mixing,where ma.k users intera.t preferentia.ly with other ma.k *** ma.e 3 key observa.ions:***,even with suboptima. effica.y in both prevention of a.quisition a.d tra.smission of infection,could substa.tia.ly decrea.e the reproduction number for COVID-19 if widely *** ma.king ma. be sufficient to suppress epidemics where R ha. been brought close to 1 via.other mea.ures(e.g.,dista.cing).3.“a.sortment”within popula.ions(the tendency for intera.tions between ma.ked individua.s to be more likely tha. intera.tions between ma.ked a.d unma.ked individua.s)would ra.idly erode the impa.t of *** such,ma.k upta.e needs to be fa.rly universa. to ha.e a. *** simple model suggests tha. widesprea. upta.e of ma.king could be determina.ive in suppressing COVID-19 epidemics in regions with R(t)a. or nea. 1.

关键词： Ma.ks Epidemiology COVID-19 Sa.S-CoV-2 Next genera.ion ma.rix Mixing a.sorta.ive Epidemics

Novel hea.ing-a.d deforma.ion-induced pha.e tra.sitions a.d mecha.ica. properties for multicomponent Zr_(50)M_(50),Zr_(50)(M,a.)_(50)a.d Zr_(50)(M,Pd)_(50)(M=Fe,Co,Ni,Cu)a.orphous a.loys

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Journa. of Ma.eria.s Science & Technology 2022年第9期104卷 109-118页

作者： J.Ding a.Inoue F.L.Kong S.L.Zhu Y.L.Pu E.Sha.a.n a.a.a.-Gha.di a.L.greer School of Ma.eria.s Science a.d Engineering Tianjin UniversityTianjin 300072China Interna.iona. Institute of Green Ma.eria.s Josai International UniversityTogane 283-8555Japan Institute of Ma.sive a.orphous a.loy Science China University of Mining TechnologyXuzhou 221116China Depa.tment of Physics King Abdulaziz UniversityJeddah 22254Saudi Arabia MISiS National University of Science and TechnologyMoscow 119049Russia School of Ma.eria.s Science a.d Engineering Lanzhou Jiaotong UniversityLanzhou 730070China Depa.tment of Ma.eria.s Science a.d Meta.lurgy University of CambridgeCambridge CB30FSUK

Multicomponent a.loys of Zr_(50)M_(50),Zr_(50)(M,a.)_(50)a.d Zr_(50)(M,Pd)_(50)(M=Fe,Co,Ni,Cu)ca. be melt-spun to obta.n a.orphous *** ma.imum thickness for fully a.orphous ribbons va.ies with composition in the ra.ge 34-53μ*** contra.t,fully a.orphous ribbons a.e not obta.na.le for bina.y Zr_(50)Ni_(50)or terna.y Zr_(50)(Ni,Cu)_(50)***-induced crysta.liza.ion occurs through:two sta.es of a.orphous[a.]→[~(a.')+B2]→[B2+B33]for Zr_(50)M_(50);a.d[a.]→[a.'+B2]→[B2+a.Zr]for Zr_(50)(M,a.)_(50);a.d a.single sta.e of[a.]→[B2]for Zr_(50)(M,Pd)_(50),while no B2 pha.e is formed for the bina.y a.d terna.y Zr_(50)Q_(50)(Q=Ni or/a.d Cu)***-spun a.orphous ribbons ha.e good bending ***,Zr_(50)M_(50)ribbons in tension show 0.22-0.28%pla.tic elonga.ion a.d work-ha.dening(the yield stress is~820 MPa.the fra.ture stress is~1200 MPa..When cold-rolled a. room tempera.ure to 30%reduction in thickness,Zr_(50)M_(50)ribbons show 10%increa.e in ha.dness,while reta.ning good bending ***-rolling induces precipita.ion of spheroida. B2 a.d irregula. B33 pa.ticles,while deforma.ion in tension induces B2,B33 a.d a.so pla.e-like monoclinic *** B2 a.d B33 pa.ticles form by polymorphic tra.sforma.ion,a.d include a.high density of interna. *** novel deforma.ioninduced precipita.ion ha. not been recognized for a.y Zr_(50)Q_(50)bina.y or terna.y *** new multicomponent systems a.e encoura.ing for future progress a. structura. a.orphous a.loys.

关键词： Multicomponent Microstructure Mecha.ica. properties Pha.e tra.sition a.orphous a.loy