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CuCr_2O_4/石墨烯复合粒子的制备及其对AP的催化作用

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推进技术 2015年第8期36卷 1257-1261页

作者：刘环环姜炜郝嘎子南京理工大学国家特种超细粉体工程技术研究中心江苏南京210094

以石墨烯为载体,采用两步法制备了CuCr2O4/石墨烯复合粒子,通过X射线衍射仪(XRD)、透射电子显微镜(TEM)对样品的结构及形貌进行了表征,并采用差示扫描量热仪(DSC)分别研究了CuCr2O4、CuCr2O4/石墨烯、石墨烯及CuCr2O4和石墨烯的混合物... 详细信息

以石墨烯为载体,采用两步法制备了CuCr2O4/石墨烯复合粒子,通过X射线衍射仪(XRD)、透射电子显微镜(TEM)对样品的结构及形貌进行了表征,并采用差示扫描量热仪(DSC)分别研究了CuCr2O4、CuCr2O4/石墨烯、石墨烯及CuCr2O4和石墨烯的混合物对AP的催化效果。结果表明,CuCr2O4纳米粒子较均匀地分布在石墨烯上,CuCr2O4/石墨烯复合粒子使AP高温分解峰温度降至382℃,降低了60℃,表观分解热增加了351j/g,达1188j/g,其催化效果明显优于CuCr2O4、石墨烯及CuCr2O4和石墨烯的混合物。

关键词：复合催化剂 AP热分解催化石墨烯

Challenges in studying geographic atrophy(ga) age-related macular degeneration: the potential of a new mouse model with ga-like features

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Neural Regeneration Research 2020年第5期15卷 863-864页

作者： j. Arjuna Ratnayaka Andrew j. Lotery Clinical and Experimental Sciences Faculty of MedicineUniversity of SouthamptonSouthamptonUK Eye Unit University Hospital Southampton NHS Foundation TrustSouthamptonUK

Loss of central vision critical to everyday activities such as reading,face-recognition and driving due to damage in the central retina (the macula) is the leading cause of irreversible blindness amongst adults in the developed *** condition,termed age-related macular degeneration (AMD),is a complex,chronic degenerative disease driven by a combination of genetic and lifestyle risk *** signs of retinal changes in people as young as 30–40 years have been reported,although these individuals appear to be ***,by the age of 65,the disease is present in ~3% of individuals,which increases dramatically to affect 1/3 of individuals by the eighth decade of *** to intermediate AMD is estimated to affect ~150 million individuals globally,with another 10 million individuals suffering from end-stage,sight-threatening *** terminal stages are broadly grouped into dry (geographic atrophy,ga) or wet (choroidal neovascular,CNV) AMD (Sarks et al.,1988;Bird et al.,2014),with similar frequencies reported in *** advances in identifying genetic risk factors,including our discoveries in this field,indicate an initial shared pathology before progressing to aforementioned late-stage ***,ga patients have no effective treatment,which may in part be due to the lack of good in vivo models for ga ***,we summarize our new findings that describe an altogether new mouse model with ga-like features which shows progressive outer retinal pathology (Ibbett et al.,2019) that can be used to gain novel insights into ga and potentially as a tool for drug development.

关键词： macula central vision degenerative disease

The Orosirian(1800–2050 Ma)plate tectonic episode:Key for reconstructing the Proterozoic tectonic record

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Geoscience Frontiers 2023年第3期14卷 1-9页

作者： Robert j.Stern Geosciences Dept. U Texas at DallasRichardsonTX 75083-0688United States

Eight lines of evidence indicate that the Orosirian Period in mid-Paleoproterozoic time was characterized by plate tectonics:ophiolites,low T/P metamorphism including eclogites,passive margin formation,tall mountains,paleomagnetic constraints,ore deposits,abundant S-type granites,and seismic images of paleo-subduction *** plate tectonic episode occurred about 1 billion years earlier than the present plate tectonic episode began in Neoproterozoic *** two plate tectonic episodes bracket the‘Boring Billion’,which may have been a protracted single lid tectonic episode that began when the supercontinent Nuna or Columbia *** of multiple lines of evidence for Orosirian plate tectonics demonstrates that Earth’s tectonic style can be reconstructed with some confidence back to at least Early Paleoproterozoic time,and thus the absence of compelling evidence for Mesoproterozoic plate tectonics is not obvious due to poor preservation.A tectono-magmatic lull2.3 ga suggests an earlier episode of single lid *** for two episodes of plate tectonics and two episodes of single lid tectonics indicates that Earth switched between single lid and plate tectonics multiple times during the last 2.4 ga.

关键词： Plate tectonics Single lid tectonics Urey ratio Paleoproterozoic

The moderating effect of physical activity on the relationship between bullying and mental health among sexual and gender minority youth

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journal of Sport and Health Science 2023年第1期12卷 106-115页

作者： Sally j.Kirklewski Ryan j.Watson Carolyn Lauckner Department of Health Promotion and Behavior University of GeorgiaAthensGA 30602USA Human Development and Family Sciences University of ConnecticutStorrsCT 06269 USA Department of Behavioral Science University of Kentucky College of MedicineUniversity of KentuckyLexingtonKY 40506USA

Background:Sexual and gender minority youth frequently experience bullying,which often contributes to higher depressive symptoms and lower *** that physical activity(PA)can mitigate depressive symptoms and improve self-esteem,we examined the moderating effect of PA on the relationship between bullying and mental health among sexual and gender minority ***:Data from the Lesbian,gay,Bisexual,Transgender,and Queer National Teen Survey(n=9890)were *** regression analyses examined the influence of history and frequency of being bullied,PA,and the interaction of these variables on depressive symptoms and *** slopes analyses were used to probe significant ***:Results indicated the importance of accounting for bullying history when examining effects of PA on mental *** was negatively related to depression(t=-4.18,pgatively related to self-esteem(t=-12.46,p<0.001).There was a significant interaction between bullying frequency and PA for depression(t=4.45,p<0.001)and self-esteem(t=-4.69,p<0.001).Post hoc analyses suggested that the positive effects of PA on mental health may be limited to those not bullied because it had a negligible effect on those who were ***:Results suggest that sexual and gender minority youth exercise interventions aiming to improve mental health should first address bullying history;otherwise,their effectiveness may be limited to those who have been bullied.

关键词： Bullying Depression Exercise LGBTQ Self-esteem Youth

Predicted Modulated Differential Rates for Direct WIMP Searches at Low Energy Transfers

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Communications in Theoretical Physics 2012年第3期57卷 504-514页

作者： j.D.Vergados CERN Theory DivisionCH 1211Geneva 23Switzerland Kavli Institute for Theoretical Physics China (KITPC) Institute of Theoretical PhysicsChinese Academy of Science

The differential event rate for direct detection of dark matter,both the time averaged and the modulated one due to the motion of the Earth,are *** calculations focus on relatively light cold dark matter candidates (WIMP) and low energy *** is shown that for sufficiently light WIMPs the extraction of relatively large nucleon cross sections is *** for some WIMP masses the modulation amplitude may change sign,meaning that,in such a case,the maximum rate may occur six months later than naively *** effect can be exploited to yield information about the mass of the dark matter candidate,if and when the observation of the modulation of the event rate is established.

关键词： dark matter WIMP direct detection WIMP-nucleus scattering event rates modulation

Higgs boson searches at the Tevatron

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Frontiers of physics 2013年第3期8卷 270-284页

作者： gavin j. Davies Imperial College London London SW7 2AZ United Kingdom

This article reviews the Higgs searches at the Tevatron, as presented over the summer of 2012; both standard model （SM） and beyond the standard model （BSM） results are discussed as detailed （arXiv： 1207.0449; Phys. Rev. Lett., 2012, 109： 071804; Phys. Rev. D, 2012, 85： 032005）. We discuss the combination of searches by the CDF and DO Collaborations for the standard model Higgs boson in the mass range 100-200 GeV/c2 produced in the the gg →H, WH, ZH, tfH, and vector boson fusion production modes, and decaying in the H → bb, H → W＋W-, H → ZZ, H →π＋π-, and H →γγ modes. The data, collected at the Fermilab Tevatron collider in p/5 collisions at √s = 1.96 TeV, correspond to integrated luminosities of up to 10 fb^-1. In the absence of signal, we expect to exclude the regions 100 〈 mH 〈 120 GeV/c2 and 139 〈 mH 〈 184 GeV/c2. We exclude, at the 95% C.L., two regions： 100 〈 mH 〈 103 GeV/c2, and 147 〈 mH 〈 180 GeV/c2. We observe a significant excess of events in the mass range between 115 and 140 GeV/c2. The local significance corresponds to 3.0 standard deviations at mH = 120 GeV/ce; the global significance （incorporating the lookelsewhere effect） for such an excess anywhere in the full mass range investigated is approximately 2.5 standard deviations. Furthermore, we separately combine searches for H→ bb-, H → W＋W- and H →γγ. We find that the excess is concentrated in the H →bb channel, appearing in the searches over a broad range of raN; the maximum local significance of 3.3 standard deviations corresponds to a global significance of approximately 3.1 standard deviations. The observed signal strengths in all channels are consistent with the expectation for a standard model Higgs boson at mH = 125 GeV/c2. The production of neutral Higgs bosons in association with b-quarks can be significantly enhanced in various beyond the standard model scenarios, including Supersymmetry. The recent combination of such searches from the two collaborations is discussed.

关键词： Higgs Tevatron

Continental velocity through Precambrian times:The link to magmatism,crustal accretion and episodes of global cooling

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Geoscience Frontiers 2013年第1期4卷 7-36页

作者： j.D.A.Piper Geomagnetism Laboratory Geology and GeophysicsSchool of Environmental SciencesUniversity of Liverpool.Liverpool L69 7ZEUK

Quasi-integrity of continental crust between Mid-Archaean and Ediacaran times is demonstrated by conformity of palaeomagnetic poles to near-static positions between -2.7-2.2 ga, -1.5-1.2 ga and -0.75-0.6 ga. Intervening data accord to coherent APW loops turning at ＂hairpins＂ focused near a continental-centric location. Although peripheral adjustments occurred during Early Proterozoic （-2.2 ga） and Grenville （- 1.1 ga） times, the crust retained a low order symmetrical crescent-shaped form constrained to a single global hemisphere until break-up in Ediacaran times. Conformity of palaeomagnetic data to specific Eulerian parameters enables definition of a master Precambrian APW path used to estimate the root mean square velocity （VRMS） of continental crust between 2.8 and 0.6 ga. A long interval of little polar movement between -2.7 and 2.2 ga correlates with global magmatic shutdown between -2.45 and 2.2 ga, whilst this interval and later slowdown at -0.75-0.6 ga to velocities of 〈2 cm/year correlate with episodes of widespread glaciation implying that these prolonged climatic anomalies had an internal origin; the reduced input of volcanically-derived atmospheric greenhouse gases is inferred to have permitted freeze-over conditions with active ice sheets extending into equatorial latitudes as established by low magnetic inclinations in glaciogenic deposits. VRMS vari- ations through Precambrian times correspond to the distribution of U-Pb ages in orogenic granitoids and detrital zircons and demonstrate that mobility of continental crust has been closely related to crustal tectonism and incrementation. Both periods of near-stillstand were followed by rapid VRMS recording massive heat release from beneath the continental lid at -2.2 and 0.6 ga. The first coincided with the Lomagundi-jatuli isotopic event and led to prolonged orogenesis accompanied by continental flooding and reconfiguration of the crust on the Earth＇s surface; the second led to continental break-up and i

关键词： Continental velocity Precambrian Palaeopangaea Palaeomagnetism Magmatism Tectonics

Dominant Lid Tectonics behaviour of continental lithosphere in Precambrian times:Palaeomagnetism confirms prolonged quasi-integrity and absence of supercontinent cycles

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Geoscience Frontiers 2018年第1期9卷 61-89页

作者： j.D.A.Piper Geomagnetism Laboratory Department of Earth and Ocean Sciences University of Liverpool

Although Plate Tectonics cannot be effectively tested by palaeomagnetism in the Precambrian aeon due to the paucity of high precision poles spanning such a long time period,the possibility of Lid Tectonics is eminently testable because it seeks accordance of the wider dataset over prolonged intervals of time;deficiencies and complexities in the data merely contribute to *** of palaeomagnetic poles across a quasi-integral continental crust for time periods of up to thousands of millions of years,together with recognition of very long intervals characterised by minimal polar motions(～2.6-2.0,～1.5-1.25 and～0.75-0.6 ga)has been used to demonstrate that Lid Tectonics dominated this *** new PALEOMAGIA database is used to refine a model for the Precambrian lid incorporating a large quasiintegral crescentric core running from South-Central Africa through Laurentia to Siberia with peripheral cratons subject to reorganisation at～2.1,～1.6 and～1.1 *** model explains low levels of tidal friction,reduced heat balance,unique petrologic and isotopic signatures,and the prolonged crustal stability of Earth's"Middle Age",whilst density concentrations of the palaeomagnetic poles show that the centre of the continental lid was persistently focussed near Earth's rotation axis from～2.8 to 0.6 *** exception was the～2.7-2.2 ga interval defined by～90°polar movements which translated the periphery of the lid to the rotation pole for this quasi-static period,a time characterised by glaciation and low levels of magmatic activity;the～2.7 ga shift correlates with key interval of mid-Archaean crustal growth to some 60-70%of the present volume and REE signatures whilst the～2.2 ga shift correlates with the Lomagundiδ～(13)C and Great Oxygenation *** palaeomagnetic signature of breakup of the lid at～0.6 ga is recorded by the world-wide Ediacaran development of passive margins and associated environmental signatures of new ocean *** event defined the end of a

关键词： Lid Tectonics Plate tectonics Archaean Proterozoic Palaeomagnetism PALEOMAGIA

Numerical Simulation of Interaction Between Laminar Flow and Elastic Sheet

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Transactions of Tianjin University 2012年第2期18卷 85-89页

作者：许栋 Munjiza A Williams j j R School of Engineering and Material Science Queen Mary University of London Tianjin Key Laboratory of Harbour and Ocean Engineering Tianjin University

A numerical simulation of the interaction between laminar flow with low Reynolds number and a highly flexible elastic sheet is presented. The mathematical model for the simulation includes a three-dimensional finitevolume based fluid solver for incompressible viscous flow and a combined finite-discrete element method for the three-dimensional deformation of solid. An immersed boundary method is used to couple the simulation of fluid and solid. It is implemented through a set of immersed boundary points scattered on the solid surface. These points provide a deformable solid wall boundary for the fluid by adding body force to Navier-Stokes equations. The force from the fluid is also obtained for each point and then applied on the boundary nodes of the solid. The vortex-induced vibration of the highly flexible elastic sheet is simulated with the established mathematical model. The simulated results for both swing pattern and oscillation frequency of the elastic sheet in low Reynolds number flow agree well with experimental data.

关键词： fluid-structure interaction (FSI) numerical simulation immersed boundary method combined finite-discrete element method three-dimensional flow