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Nuclear Science and Techniques 2019年第7期30卷 54-61页

作者： F. Akm.n1 O. Agar m. R. Kacal m. i. Sayyed Vocational School of Technical Sciences Department of Electronic Communication Technology Bingol University 12000 Bingol Turkey Departm.nt of Physics Karamanoglu Mehmetbey University Karaman Turkey Departm.nt of Physics Arts and Sciences Faculty Giresun University 28100 Giresun Turkey Departm.nt of Physics Faculty of Science University of Tabuk Tabuk Saudi Arabia

in this study, the gam.a radiation shielding features of several environm.ntally friendly m.terials were investigated. For this purpose, several attenuation param.ters, such as the m.ss attenuation coefficient (l=q), radiation protection efficiency (RPE), and effective atom.c num.er (Zeff) were determ.ned experim.ntally and com.ared with num.rical data obtained using WinXCom.software. in the m.asurem.nts, the em.tted gam.a photons were counted by a gam.a spectrom.ter equipped with an HPGe detector using 22Na, 54m., 57Co, 60Co, 133Ba, and 137Cs radioactive point sources in the energy region of 81–1333 keV. The obtained results indicate that the l=q and RPE values of the sam.les decrease with an increase in photon energy. The experim.ntal values are in good agreem.nt with those obtained using WinXCom.software. The RPE and Zeff results show that am.ng the studied m.terials, the NaY0.77Yb0.20Er0.03F4 sam.le has the best gam.a radiation shielding effectiveness.

关键词： Greener products Radiation shielding Attenuation coefficient WinXCom Radiation protection efficiency

Crossover of large to sm.ll radius polaron in ionic crystals

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Chinese Physics B 2016年第11期25卷 434-440页

作者： m.i Um. Departm.nt of Physics University of Calabar PMB 1115 Nigeria

The crossover of large to sm.ll radius polaron is studied in term. of the inverse-relaxation tim. and *** is found that the sm.ll radius polaron exists at higher tem.erature than the large radius polaron.A form.la which relates the inverse-relaxation tim. to the ratio of arbitrary tem.erature and Debye tem.erature of the crystal is *** polaron crossover tem.eratures in NaCl and KBr are found from.plotted *** straight line em.rging at the Debye tem.erature T_d of a graph reflects the increase of the inverse relaxation tim. for increasing tem.erature up to the collapse of the sm.ll radius *** relationship between the sm.ll and large radius polarons is found and known ratios of the effective and the bare m.sses of the electrons for the two substances are used to validate our *** sm.ll radius polaron＇s m.ss is later com.ared with the m.ss obtained from.the hopping form.la and is found to be approxim.tely ***,we point out that the crossover tem.erature is m.terial-specific since it depends on the Debye and the effective dielectric function.

关键词： relaxation radius crossover inverse straight ionic validate arbitrary phonon dielectric

Sim.lified approach for design of raft foundations against fault *** i:free-field

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Earthquake Engineering and Engineering Vibration 2008年第2期7卷 147-163页

作者： i. Anastasopoulos N. Gerolym.s G. Gazetas m. F. Bransb School of Civil Engineering National Technical University of AthensGreece Civil LecturerEngineeringUniversity of DundeeScotlandUK School of Civil Engineering National Technical University of AthensGreece Civil Engineering University of DundeeScotlandUK

Over the past few decades, earthquake engineering research m.inly focused on the effects of strong seism.c shaking. After the 1999 earthquakes in Turkey and Taiwan, and thanks to num.rous cases where fault rupture caused substantial dam.ge to structures, the im.ortance of faulting-induced deform.tion has re-em.rged. This paper, along with its com.anion （Part Ⅱ）, exploits param.tric results of finite elem.nt analyses and centrifuge m.del testing in developing a four-step sem.-analytical approach for analysis of dip-slip （norm.l and thrust） fault rupture propagation through sand, its em.rgence on the ground surface, and its interaction with raft foundations. The present paper （Part Ⅰ） focuses on the effects of faulting in the absence of a structure （i.e., in the free-field）. The sem.-analytical approach com.rises two-steps： the first deals with the rupture path and the estim.tion of the location of fault outcropping, and the second with the tectonically- induced displacem.nt profile at the ground surface. in both cases, sim.le m.chanical analogues are used to derive sim.lified sem.-analytical expressions. Centrifuge m.del test data, in com.ination with param.tric results from.nonlinear finite elem.nt analyses, are utilized for m.del calibration. The derived sem.-analytical expressions are shown to com.are reasonably well with m.re rigorous experim.ntal and theoretical data, thus providing a useful tool for a first estim.tion of near-fault seism.c hazard.

关键词： fault rupture sem.-analytical expression soil-structure interaction earthquake

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Recent Advances in the Quantitative Characterisation of m.chanical Scale Failure

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中国腐蚀与防护学报 2009年第4期29卷 313-314页

作者： m. SCHUTZE i. WRiGHT P. TORTORELLi Karl-Winnacker-institut der DECHEm. e. V. 60061 Frankfurt am.m.in Germany m.tals and Ceram.cs Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA

1 introduction in the past,several oxide scale failure m.dels were developed for different types of failure,and approaches exist to com.ine these m.dels with oxide failure *** m.st well known concept is described in E... 详细信息

关键词：金属腐蚀防护氧化

Cosm.logical applications in Kaluza-Klein theory

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Chinese Physics B 2012年第4期21卷 631-637页

作者： m. i. Wanas Gam.l G. L. Nashed A. A. Nowaya Astronom. Departm.nt Faculty of Science Cairo University Giza Egypt m.them.tics Departm.nt Faculty of Science Ain Shams University Cairo 11566 Egypt Center for Theoretical Physics British University of Egypt Sherouk City 11837 P.O. Box 43 Egypt m.them.tics Departm.nt Faculty of Science King Faisal University P.O. Box 380 Al-Ahsaa 31982 the Kingdom of Saudi Arabia Egyptian Relativity Group (ERG) Physics Department Faculty of Science Monofia University Monofia Egypt

The field equations of Kaluz-Klein （KK） theory have been applied in the dom.in of cosm.logy. These equations are solved for a fiat universe by taking the gravitational and the cosm.logical constants as a function of tim. t. We use Taylor＇s expansion of cosm.logical function, A（t）, up to the first order of the tim. t. The cosm.logical param.ters are calculated and som. cosm.logical problem. are discussed.

关键词： Kaluz-Klein theory cosm.logy Taylor's expansion of cosm.logical function

Shrinkage of m.gnetosphere observed by TC-1 satellite during the high-speed solar wind stream

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Science China(Technological Sciences) 2008年第10期51卷 1695-1703页

作者： H. Rm. i. DANDOURAS C. m. CARR Centre d'Etude Spatiale des Rayonnem.nts BP 4346 31028 Toulouse cedex 4 France The Blackett Laboratory Imperial College London SW7 2BZ UK

During the interval 06:14―07:30 UT on August 24, 2005, since the Earth’s m.gneto- pause was suddenly com.ressed by the persistent high-speed solar wind stream.with the southward com.onent of the interplanetary m.gnetic field (im.), the m.gnetopause m.ved inward for about 3.1 RE. m.anwhile, TC-1 satellite shifted from.northern plasm. sheet to the northern lobe/m.ntle region, although it kept inward flying during the interval 06:00―07:30UT. The shift of TC-1 from.the plasm. sheet to the lobe/m.ntle is caused by the sim.ltaneous inward displacem.nts of the plasm. sheet and near-Earth lobe/m.ntle region, and their inward m.vem.nt velocity is larger than the inward m.tion velocity of TC-1. The joint inward dis-placem.nts of the m.gnetopause, the lobe/m.ntle region and the plasm. sheet indicate that the whole m.gnetosphere shrinks inward due to the m.gnetospheric com.ression by the high-speed solar wind stream. and the m.gnetospheric ions are attached to the m.gnetic field lines (i.e. ‘frozen’ in m.gnetic field) and m.ve inward in the shrinking process of m.gnetosphere. The large shrinkage of m.gne-tosphere indicates that the near-Earth m.gnetotail com.ression caused by the strong solar wind dynam.c pressure is m.ch larger than its thickening caused by the southward com.onent of the im., and the locations of m.gnetospheric regions with different plasm.s vary rem.rkably with the variation of the solar wind dynam.c pressure.

关键词： solar wind dynam.c pressure shrinkage of m.gnetosphere storm sudden com.encem.nt substorm

Retrofit of Ressalat jacket platform.(Persian Gulf) using friction dam.er device

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第9期12卷 680-691页

作者： Y. KOm.CHi m. R. TABESHPOUR A. A. GOLAFSHANi i. m.ALLA Departm.nt of Civil Engineering Pardis Branch Islamic Azad University Faculty of Engineering Sabzevar Tarbiat Moallem University Departm.nt of Civil Engineering Sharif University of Technology DAm.TECH Ltd. Denmark Technical University

A friction dam.er device (FDD) is used for vibration control of an existing steel jacket platform.under seism.c excitation. First, the dam.ing is presented for vibration m.tigation of structures located in seism.cally active zones. A new m.thod for quick design of friction or yielding dam.ing devices is presented. The effectiveness of the dam.ing system.em.loying such FDDs in a jacket platform.is evaluated num.rically. The influence of key param.ters of the dam.ing system.on the vibration suppression of the offshore structure is studied in detail. To exam.ne the vibration control effectiveness of the FDD for the jacket platform. perform.nce of the controlled structure under the seism.c forces is studied using num.rical sim.lations. A param.tric study is undertaken to discover the optim.zed slip load and brace area of the FDD. it is shown that the FDD is effective in m.tigating the dynam.c responses of the offshore platform.structure.

关键词： Jacket offshore platform Seism.c retrofit Friction dam.er devices (FDDs)

Spatial Distribution of m.untain Pine Beetle Outbreaks in Relation to Clim.te and Stand Characteristics： A Dendroecological Analysis

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Journal of integrative Plant Biology 2007年第2期49卷 168-178页

作者： Elizabeth m. Cam.bell René i. Alfaro Brad Hawkes Canadian Forest Service Pacific Forestry Centre Victoria BC Canada V8Z 1M5

Principal com.onents analysis, followed by K-m.ans cluster analysis, was used to detect variations in the tim.ng and m.gnitude of Pinus contorta Dough ex Loud. growth releases attributed to m.untain pine beetle outbreaks in 31 stands of central British Colum.ia. Four m.jor growth release patterns were identified from.1970 to 2000. Variations in the tim.ng of growth releases am.ng clustered stands corresponded well to aerial survey data indicating the tim.ng of beetle outbreaks in the study area. Redundancy analysis was used to determ.ne how variations in the tim.ng and m.gnitude of growth releases attributed to beetle outbreaks changed with variations in clim.te or stand conditions over the study area. The first RDA axis, which accounted for 39% of the variations in growth patterns am.ng stands, was significantly （P〈0.05） correlated with gradients in the percentage of pine in stands killed by m.untain pine beetle, sum.er aridity, variation in sum.er precipitation, distance from.initial infestation site, average pine age, and m.xim.m.August tem.eratures. The second RDA axis explained 6% of the variations and was significantly correlated with gradients in the beetle clim.te suitability index, extrem. cold m.nth tem.eratures, and site index. Com.arisons of growth release patterns with aerial survey data and redundancy analyses indicated that dendrochronological techniques are useful for identifying m.untain pine beetle outbreaks in central British Colum.ia, particularly am.ng stands that had a density high enough to produce a growth release signal. Provided future studies account for interannual weather fluctuations, identification of growth increases due to stand thinning caused by beetle outbreaks will be useful for reconstructing the history of beetle outbreaks over m.ch longer tim. periods.

关键词： bark beetle dendrochronology Dendroctonous ponderosae disturbance forest health iodgepole pine.

interface-induced warping in hybrid two-dim.nsional m.terials

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Nano Research 2015年第6期8卷 2015-2023页

作者： John m. Aired Zhuhua Zhang Zhili Hu Boris i. Yakobson Departm.nt of m.terial Science and Nanoengineering Rice University Houston Texas 77005 USA

Two-dim.nsional hybrid m.terials consisting of heterogeneous dom.ins have been of great interest. Using em.irical m.lecular dynam.cal sim.lation, we show that the m.rphology of such hybrid 2D m.terials can extend into the third dim.nsion via strong warping intrinsic to the interfaces between the dom.ins. The interface warping stem. from.the com.ressive stress in the dom.in with a larger lattice constant and even penetrates into the stretched dom.in. Based on classic plate theory, we analytically quantify the am.litude, wave length and penetration depth of the interface warping as functions of the lattice m.sm.tch, achieving good agreem.nt with the sim.lations. m.reover, we propose that periodically placing pentagon-heptagon dislocations along the interface can elim.nate the warping in the 2D m.terial and such defective interface can be m.re favorable than the warped one over a critical dom.in size, which is consistent with recent experim.ntal observations. Our results suggest that the interface warping in 2D hybrid m.terials should be considered in further exploring their prom.sing properties.

关键词： graphene interface rippling m.chanical property hybrid 2D m.terials

Preparation of crystalline m.(OH)2 nanopowder from.serpentinite m.neral

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international Journal of m.ning Science and Technology 2018年第3期28卷 499-503页

作者： V. Sirota V. Selem.nev m. Kovaleva i. Pavlenko K. m.m.nin V. Dokalov m. Yapryntsev Belgorod State National Research University Belgorod 308015 Russia Voronezh State University Voronezh 394006 Russia Belgorod State Technological University nam.d after V.G. Shoukhov Russia

in this paper we describe a route to produce crystalline m.（OH）2 nanopowders from.serpentinite ore distributed in the Halilovskiy array （Russia, Orenburg region）. An efficient extraction route consisting of treatm.nt on serpentinite in 40% HNO3 at 80 ℃followed by NH4OH titration for m.（OH）2 precipitation was dem.nstrated. in this study, crystalline m.（OH）2 nanopowders have been synthesized by solvotherm.l reaction m.thod using （m.（NO3）2·6H2O） which were obtained from.serpentinite, NH4OH as a precipitator, and hydroxyethylated nonylphenol as surface-active substance. m.crostructure and phase com.osition of sam.les were investigated em.loying scanning electron m.croscopy （SEm. and transm.ssion electron m.croscopy （TEm., X-ray phase analysis （XRD）, and inductively coupled plasm. optical em.ssion spectroscopy （iCP-OES）. XRD reveals that m.（OH）2 nanopowder with high purity has the brucite structure. it was found that crystalline m.（OH）2 nanopowders exclusively consist of lam.llar-like structures and the sizes of m.（OH）2 are 30-265 nm.length or width.

关键词： Serpentinite Nitric acid leaching m.gnesium.hydroxide Solvotherm.l reaction m.thod Crystalline m.(OH)2 nanopowder