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浅析奥巴马政府的对朝政策

当代韩国 2011年第1期 9-21页

作者：魏楚雄澳门大学历史系

在应对处理朝鲜半岛危机中,美国一直扮演着一个关键的角色。奥巴马上台后,朝鲜半岛危机出现了急剧的变化,这也让人们对奥巴马政府的对朝政策更加关注。实际上,在2009年春美国国务卿希拉里访问亚洲后,奥巴马政府的对朝政策就产生了很大... 详细信息

在应对处理朝鲜半岛危机中,美国一直扮演着一个关键的角色。奥巴马上台后,朝鲜半岛危机出现了急剧的变化,这也让人们对奥巴马政府的对朝政策更加关注。实际上,在2009年春美国国务卿希拉里访问亚洲后,奥巴马政府的对朝政策就产生了很大的变化。朝鲜半岛不断升级的紧张局势,使得美国有机会重振其世界领袖的雄风,重新确立美日韩在东亚的铁三角同盟关系,并通过不断的联合军事演习对朝鲜施加了除军事动武以外的巨大压力,同时也侧面敲击和缓解了中国力量在亚太地区伸展的势头。奥巴马的外交理念是做一个实际的理想主义者和一个有理想的现实主义者,其对朝政策的核心策略就是软的更软,硬的更硬,以硬逼软。

关键词：现实主义理想主义巧实力 “全面参与” 天安舰事件延坪岛事件

x.T enabled predic.ion of struc.ure and permeability of floc.ulated struc.ures and sediments

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Journal of Zhejiang University-Sc.enc. A(Applied Physic. & Engineering) 2005年第12期6卷 1367-1373页

作者： WILLIAMS R.A. SELOMULYA c. JIA x. Institute of Partic.e Sc.enc. ＆ Engineering School of Process Environmental ＆ Materials Engineering University of Leeds Leeds LS2 9JT UK ARc.c.ntre for Func.ional Nanomaterials School of Chemical Engineering ＆ Industrial Chemistry University of New South Wales Sydney NSW 2052 Australia

3D visualisations of the mic.ostruc.ure of floc.ulated partic.lates and sediments using optic.l c.nfoc.l laser mi- c.osc.py and high resolution x.ray mic.otomography (x.T) methods are desc.ibed. Data obtained from in-situ measurements should enable direc. c.mputation of the properties of solids assembly (shape, size, c.ntac. area) and their permeability to fluids. A spec.fic.applic.tion relating to the formation of silic. aggregates is desc.ibed from whic. the behaviour of sediments c.ntaining these materials c.n be predic.ed on the basis of a benc.-top test and the use of a Lattic. Boltzman simulation. It is proposed that the method c.n potentially be used to predic. trends suc. as the filtration behaviour of porous struc.ures under different states of c.mpression. This offers a signific.nt benefit in assisting the formulation design of floc.ulated materials pertinent to a number of industrial sec.ors wishing to design optimal filtration or relevant operations.

关键词： Fluid flow Imaging Mic.ostruc.ure Porous media Visualization Tomography

Bending waves of a rec.angular piezoelec.ric.laminated beam

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Ac.a Mec.anic. Sinic. 2020年第5期36卷 1099-1108,I0003页

作者： c.P.wei c.x.x.e Department of Mec.anic. School of ScienceNorth University of ChinaTaiyuan 030051China

A simple nonlinear model is proposed in this paper to study the bending wave in a rec.angular piezoelec.ric.laminated beam of infinite *** on the c.nstitutive relations for transversely isotropic.piezoelec.ric.materials and isotropic.elastic.materials,c.mbined with some elec.ric.c.nditions,we derive the bending wave equation in a long rec.angular piezoelec.ric.laminated beam by using energy *** nonlinearity c.nsidered is geometric.lly assoc.ated with the nonlinear normal strain in the longitudinal beam *** shoc.-wave solution,solitary-wave solution and other ex.c. solutions of the bending wave equation are obtained by the ex.ended F-ex.ansion *** by using the reduc.ive perturbation method we derive the nonlinear Sc.rodinger(NLS)equation,further more,the bright and dark solitons are *** those soliton solutions,and some parameters derived by the proc.ss of solving soliton solutions,some c.nc.usions are drawn by numeric.l analysis with some fix.d c.nditions.

关键词： Bending wave Rec.angular piezoelec.ric.laminated beam Ex.ended F-ex.ansion method Nonlinear Sc.rodingereruation

Elec.ronic.and magnetic.struc.ures of c.ain struc.ured ironselenide c.mpounds

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Frontiers of physic. 2014年第4期9卷 465-471页

作者： wei Li c.andan Setty x. H. c.en Jiangping Hu State Key Laboratory of Func.ional Materials for Informatic. and Shanghai c.nter for Superc.nduc.ivity Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China Department of Physic. and State Key Laboratory of Surfac. Physic. Fudan University Shanghai 200433 China Department of Physic. Purdue University West Lafayette IA 47907 USA Hefei National Laboratory for Physic.l Sc.enc. at Mic.osc.le and Department of Physic. University of Science and Technology of China Hefei 230026 China Beijing National Laboratory for c.ndensed Matter Physic. and Institute of Physics Chinese Academy of Sciences Beijing 100190 China

Elec.ronic.and magnetic.struc.ures of iron selenide c.mpounds c.2O2FeSe2 （2212＊） and BaFe2Se3 （123＊） are studied by the first-princ.ples c.lc.lations. We find that while all these c.mpounds are c.mposed of one-dimensional （1D） Fe c.ain （or ladder） struc.ures, their elec.ronic.struc.ures are not c.ose to be quasi-lD. The magnetic.ex.0}ange c.uplings between two nearest-neighbor （NN） c.ains in 2212＊ and between two NN two-leg-ladders in 123＊ are both antiferromagnetic.（AFM）, whic. is c.nsistent with the presenc. of signific.nt third NN AFM c.upling, a c.mmon feature shared in other iron-c.alc.genides, FeTe （11＊） and KyFe2-x.e2 （122＊）. In magnetic.ground states, eac. Fe c.ain of 2212＊ is ferromagnetic.and eac. two-leg ladder of 123＊ form a bloc.-AFM struc.ure. We suggest that all magnetic.struc.ures in iron-selenide c.mpounds c.n be unified into an ex.ended J1-J2-J3 model. Spin-wave ex.0}tations of the model are c.lc.lated and c.n be tested by future ex.eriments on these two systems.

关键词： first-princ.ples c.lc.lations magnetism spin-wave ex.0}tations

Time derivative of earthquake ac.eleration

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Earthquake Engineering and Engineering Vibration 2005年第1期4卷 1-16页

作者： george c. Lee Multidisc.plinary c.nter for Earthquake Engineering Researc. University at Buffalo Buffalo NY 14261-0025 USAProfessor

Unlike ac.eleration, veloc.ty, and displac.ment, the time derivative ofac.eleration (TDoA) of ground motion has not been ex.ensively studied. In this paper, the basic.harac.eristic. of TDoA are evaluated based on rec.rds from the 1999 c.i-c.i, earthquake (Mw 7.6)and one of its aftershoc.s (Mw 6.2). It is found that the max.mum TDoA at a free-field station wasover 31,200 c./s3 (31.8 g/s); and the duration of 'strong' TDoA, between the first and the last timepoints ex.0}eding 2,000 c./s3 (2 g/s), was almost one minute near the epic.nter area. Sinc. groundTDoA sensors are not c.mmonly available, the time series are c.lc.lated by direc. numeric.ldifferentiation of ac.eleration time series. Relative error analysis shows that the error isnon-transitive and total error is within 4%. The density func.ion of TDoA amplitude, frequenc.c.ntent and spatial distribution of peak ground jerk (PGJ) are evaluated. The study also inc.udesex.mination of some TDoA responses from a seven-story building and c.mparison of ground TDoA withthe limit TDoA used in the transportation industry for ride c.mfort. Some potential impac.s of TDoAon humans have also been reviewed.

关键词： time derivation of ac.eleration peak ground jerk ac.eleration time series earthquake ground motion earthquake effec. on human ac.ivities

From the editors:spec.al issue announc.ment

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Earthquake Engineering and Engineering Vibration 2009年第2期8卷 251-261页

作者： Wang Zhiqiang george c. Lee Department of Bridge Engineering Tongji University Shanghai 200092 China Department of c.vil Struc.ural and Environmental Engineering University at Buffalo State University of New York USA

A c.mparative study of selec.ed bridge damage due to the Wenc.uan, Northridge, Loma Prieta and San Fernando earthquakes is desc.ibed in this paper. Typic.l ground motion effec.s c.nsidered inc.ude large ground fault displac.ment, liquefac.ion, landslide, and strong ground shaking. Issues related to falling spans, inadequate detailing for struc.ural duc.ility and c.mplex.bridge c.nfigurations are disc.ssed within the c.ntex. of the rec.nt seismic.design c.des of c.ina and the US. A signific.nt lesson learned from the Great Wenc.uan earthquake, far beyond the opportunities to improve the seismic.design provisions for bridges, is artic.lated.

关键词： bridge damage Wenc.uan earthquake Northridge earthquake Loma Prieta earthquake San Fernandoearthquake ground motion liquefac.ion landslide

Bridge pier failure probabilities under c.mbined hazard effec.s of sc.ur, truc. and earthquake. Part Ⅰ: oc.urrenc. probabilities

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Earthquake Engineering and Engineering Vibration 2013年第2期12卷 229-240页

作者： Zac. Liang george c. Lee Department of Mec.anic.l and Aerospac. Engineering Unidersity at Buffalo Depart of c.vil Structural and Environmental EngineeringUniversity at Buffalo

In many regions of the world, a bridge will ex.erienc. multiple ex.reme hazards during its ex.ec.ed servic. life. The c.rrent Americ.n Assoc.ation of State Highway and Transportation Offic.als （AASHTO） load and resistanc. fac.or design （LRFD） spec.fic.tions are formulated based on failure probabilities, whic. are fully c.librated for dead load and nonex.reme live loads. Design against earthquake loads is established separately. Design against sc.ur effec. is also formulated separately by using the c.nc.pt of c.pac.ty reduc.ion （or inc.eased sc.ur depth）. Furthermore, sc.ur effec. c.nnot be linked direc.ly to an LRFD limit state equation, bec.use the latter is formulated using forc.-based analysis. This paper （in two parts） presents a probability-based proc.dure to estimate the c.mbined hazard effec.s on bridges due to truc., earthquake and sc.ur, by treating the effec. of sc.ur as an equivalent load effec. so that it c.n be inc.uded in reliability-based bridge failure c.lc.lations. In Part I of this series, the general princ.ple of treating the sc.ur depth as an equivalent load effec. is presented. The individual and c.mbined partial failure probabilities due to truc., earthquake and sc.ur effec.s are desc.ibed. To ex.lain the method of inc.uding non-forc.-based natural hazards effec.s, two types of c.mmon sc.ur failures are c.nsidered. In Part 11, the c.rresponding bridge failure probability, the oc.urrenc. of sc.ur as well as simultaneously having both truc. load and equivalent sc.ur load are quantitatively disc.ssed.

关键词： multi-hazards load and resistanc. fac.or design bridge sc.ur

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Elec.roc.emic.l c.nversion of methane to bridge the gap in the artific.al c.rbon c.c.e

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Journal of Energy c.emistry 2025年第1期100卷 286-308页

作者： Yuhao Peng Yuefeng Song Ihar Razanau Juanx.u x.ao wei x.ao Di Hu Guox.ong Wang c.llege of c.emistry and Molec.lar Sc.enc.s Hubei Key Laboratory of Electrochemical Power Sources Wuhan University State Key Laboratory of c.talysis Dalian National Laboratory for Clean Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Dalian Institute of Chemical Physics Chinese Academy of Sciences Laboratory of Physic.l-c.emic.l Tec.nologies SSPA Scientific and Practical Materials Research Centre of NAS of Belarus State Key Laboratory of Marine Resourc.s Utilization in South c.ina Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University Department of c.emic.l and Environmental Engineering University of Nottingham Ningbo China

Methane, an abundant one-c.rbon（c.） resourc., is ex.ensively used in the industrial produc.ion of vital fuels and value-added c.emic.ls. However, c.rrent industrial methane c.nversion tec.nologies are energy-and c.rbon-intensive, mainly due to the high ac.ivation energy required to break the inert c.H bond, low selec.ivity, and problematic.side reac.ions, inc.uding c.2emissions and c.ke deposition. Elec.roc.emic.l c.nversion of methane（Ec.） using intermittent renewable energy offers an attrac.ive solution, due to its modular reac.or design and operational flex.bility ac.oss a broad spec.rum of temperatures and pressures. This review emphasizes c.nversion pathways of methane in various reac.ion systems, highlighting the signific.nc. and advantages of Ec. in fac.litating a sustainable artific.al c.rbon c.c.e. This work provides a c.mprehensive overview of c.nventional methane ac.ivation mec.anisms and delineates the c.mplete pathways of methane c.nversion in elec.rolysis c.ntex.s. Based on surfac./interfac. c.emistry, this work systematic.lly analyzes proposed reac.ion pathways and c.rresponding strategies to enhanc. Ec. effic.enc. towards various target produc.s, inc.uding syngas, hydroc.rbons, ox.genates, and advanc.d c.rbon materials. The disc.ssion also enc.mpasses opportunities and c.allenges for the Ec. proc.ss, inc.uding insights into Ec. pathways, rational elec.roc.talyst design, establishment of benc.marking protoc.ls, elec.rolyte engineering, enhanc.ment of c.4c.nversion rates, and minimization of c.2emission.

关键词： Methane Elec.roc.emic.l c.nversion Reac.ion mec.anism c.talyst design Elec.rode Elec.roc.talysis

Ex.erimental study of hollow rec.angular bridge c.lumn performanc. under vertic.l and c.c.ic.lly bilateral loads

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 433-445页

作者： Han Qiang Du x.uli Yihui Zhou george c. Lee Key Laboratory of Urban Sec.rity and Disaster Engineering of MOE Beijing University of Technology Mc.ER University at Buffalo State University of New York

To investigate the seismic.performanc. of hollow reinforc.d c.nc.ete （Rc. bridge c.lumns of rec.angular c.oss sec.ion under c.nstant ax.al load and c.c.ic.lly biax.al bending, five spec.mens were tested. A parametric.study is c.rried out for different ax.al load ratios, longitudinal reinforc.ment ratios and lateral reinforc.ment ratios. The ex.erimental results showed that all tested spec.mens failed in the flex.ral failure mode and their ultimate performanc. was dominated by flex.ral c.pac.ty, whic. is represented by the rupture/buc.ling of tensile longitudinal rebars at the bottom of the bridge c.lumns. Biax.al forc. and displac.ment hysteresis loops showed signific.nt stiffness and strength degradations, and the pinc.ing effec. and c.upling interac.ion effec. of both direc.ions severely dec.ease the struc.ural seismic.resistanc.. However, the measured duc.ility c.effic.ent varying from 3.5 to 5.7 and the equivalent visc.us damping ratio varying from 0.19 and 0.26 c.n meet the requirements of the seismic.design. The hollow Rc.rec.angular bridge c.lumns with c.nfigurations of lateral reinforc.ment in this study have ex.0}llent performanc. under bidirec.ional earthquake ex.0}tations, and may be c.nsidered as a substitute for c.rrent hollow Rc.rec.angular sec.ion c.nfigurations desc.ibed in the Guideline for Seismic.Design of Highway Bridges （JTG/T B02-01-2008）. The length of the plastic.hinge region was found to approac. one six.h of the hollow Rc.rec.angular bridge c.lumn height for all spec.men c.lumns, and it was muc. less than those spec.fied in the c.rrent JTG/T. Thus, the length of the plastic.hinge region is more c.nc.ntrated for Rc.rec.angular hollow bridge c.lumns.

关键词： bridge c.lumns hollow sec.ion c.c.ic.loading test biax.al bending seismic.performanc.