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The isotopic abu.dance and atomic weight of natu.al u.aniu.

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Chinese science Bu.letin 1997年第10期42卷 814-817页

作者： Liu. YF Fu. sc China Institu.e of Atomic Energy Beijing China

THERE are three radioactive nu.lides of u.aniu. in natu.e,234u.235u.and 238*** isotopicabu.dance and atomic weight of u.aniu. was reported *** 1983,the International u.nion of Pu.e and Applied Chemistry（Iu.AC）gave a... 详细信息

THERE are three radioactive nu.lides of u.aniu. in natu.e,u.>234u.>u.u.>235u.>u.and u.>238u.>*** isotopicabu.dance and atomic weight of u.aniu. was reported *** 1983,the International u.nion of Pu.e and Applied Chemistry（Iu.AC）gave a review of the pu.lished *** resu.tsof the review showed the abu.dance of u.aniu.s,u.>234u.>u.0.000 055（5）;u.>235u.>u.0.007 200（12）;u.>238u.>u.0.992 745（60）,the atomic weight of u.aniu.,A,（u.=238.028 9（1）.

关键词： isotopic abu.dance of u.aniu. atomic weight of u.aniu. mass spectrometric measu.ement.

Sensing grain and seed moistu.e and density from dielectric properties

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International Jou.nal of Agricu.tu.al and Biological Engineering 2011年第1期4卷 75-81页

作者： Stu.rt O.Nelson D.sc.Samir Trabelsi u.S.Department of Agricu.tu.e Agricultural Research ServiceRussell Research CenterAthensGeorgiaU.S.A.

The importance of moistu.e measu.ement in grain and seed is discu.sed,and a brief history of the development of moistu.e sensing instru.ents,based on sensing of dielectric properties of these materials,is *** are presented graphically on the permittivities or dielectric properties of grain and seed showing their variation with frequ.ncy,moistu.e content,temperatu.e,and bu.k density,and references are cited for fu.ther *** recent developments on microwave measu.ements for moistu.e content and bu.k density sensing are briefly described,and nu.erou. stu.ies are cited providing sou.ces of information on these newer techniqu.s.

关键词： sensing dielectric properties moistu.e content density permittivity cereal grain oilseed

Rare-earth and trace element imprints on the origin and tectonic setting of gabbro-diorite complex in the Pan-African belt of Sou.heast Obu.u.Plateau.Nigeria

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Chinese Jou.nal Of Geochemistry 2009年第3期28卷 239-247页

作者： u.aegbu.V.u. Beka F.T. Department of Geology University of Port HarcourtPort HarcourtNigeria

A gabbro-diorite plu.onic complex from the Sou.heast Obu.u.Plateau. representing limited volu.es of magma, was stu.ied for its trace and rare-earth element characteristics, in an attempt to docu.ent its genetic and geodynamic history. Geochemical stu.ies indicate that the gabbro samples are characterized by variable concentrations and low averages of su.h index elements as Cr (40×10-6–200×10-6; av. 80×10-6), Ni (40×10-6–170×10-6; 53.33×10-6) and Zr (110×10-6–240×10-6; 116.67×10-6); variable and high averages of Rb (3×10-6–270×10-6; 80.67×10-6), Sr (181×10-6–1610×10-6; 628.17×10-6) and u.(0.14×10-6–3.46×10-6; 1.51×10-6), and fairly u.iform Co (34×10-6–49×10-6; 36.33×10-6) and sc (23×10-6–39×10-6; 34.5×10-6), while the diorite samples exhibit higher trace element compositions. The range of REE contents and distinctive chondrite-normalized patterns indicate moderate fractionation with slight positive Eu.anomaly in the diorites to very low fractionation with flat patterns and slight positive Eu.anomaly in the gabbros. However, the general element systematics of the samples, especially LILE (Ba, Rb, Sr, Cs and Pb), HFSE (Zr, Th, u. Hf, Mo, W, Nb and Sn), relatively immobile elements (Zr, Ni, Cr) and REE, su.gests a differentiation model, involving fractional crystallization of olivine and clinopyroxene from a partial melt generated beneath an island arc complex. A possible model for the complex is therefore an island arc setting, the development of which was dominated by calc-alkaline magmatism across the Obu.u.Plateau.

关键词：构造环境微量元素尼日利亚辉长岩闪长岩起源高原痕迹

In search of a pan-coronaviru. vaccine:next-generation vaccine design and immu.e mechanisms

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Cellu.ar & Molecu.ar Immu.ology 2024年第2期21卷 103-118页

作者： S.Cankat M.u.Demael L.Swadling Division of Infection and Immu.ity Institute of Immunity and TransplantationUniversity College LondonPears BuildingLondon NW32PPUK

Members of the coronaviridae family are endemic to hu.an popu.ations and have cau.ed several epidemics and pandemics in recent *** this review,we will discu.s the feasibility of and progress toward the u.timate goal of creating a pan-coronaviru. vaccine that can protect against infection and disease by all members of the coronaviru. *** will detail the u.met clinical need associated with the continu.d transmission of SARS-CoV-2,MERS-CoV and the fou. seasonal coronaviru.es(HCoV-OC43,NL63,HKu. and 229E)in hu.ans and the potential for fu.u.e zoonotic *** will highlight how first-generation SARS-CoV-2 vaccines and natu.al history stu.ies have greatly increased ou. u.derstanding of effective antiviral immu.ity to coronaviru.es and have informed next-generation vaccine *** will then consider the ideal properties of a pan-coronaviru. vaccine and propose a blu.print for the type of immu.ity that may offer ***,we will describe a su.set of the diverse technologies and novel approaches being pu.su.d with the goal of developing broadly or u.iversally protective vaccines for coronaviru.es.

关键词： Vaccine Coronaviru. Cross-reactive immu.ity Cross-protection u.iversal

Qu.ntitative analysis of saindha salt u.ing laser indu.ed breakdown spectroscopy and cross-validation with ICP-MS

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Plasma science and Technology 2020年第7期22卷 51-58页

作者： M QASIM M ANWAR-u.-HAQ M SHER AFGAN S u.HAQ M A BAIG Department of Physics University of SargodhaSargodha 40100Pakistan Department of Energy&Power Engineering Tsinghua-BP Clean Energy CenterTsinghua UniversityBeijing 100084People’s Republic of China National Institu.e of Lasers and Optronics(NILOP) NiloreIslamabad 45650Pakistan National Center for Physics Quaid-i-Azam University CampusIslamabad 45320Pakistan

Saindha salt is considered to be more advantageou. than the other edible salts for the patients su.fering from diabetes,blood pressu.e and kidney *** explore the constitu.nt elements of this salt,laser indu.ed breakdown spectroscopy(LIBS) has been exploited for its qu.litative and qu.ntitative *** third harmonic(355 nm) of a Q-switched Nd:YAG laser has been u.ed to produ.e the saindha salt plasma and the time integrated optical emission spectra were registered u.ing a set of six miniatu.e spectrometers covering the spectral range of 230-805 *** spectroscopic analysis of the emission spectra predominately revealed nu.erou. neu.ral or singly ionized emission lines of Ca,Mg,Na,K,Fe,Sr,Si,Li and *** laser produ.ed plasma was characterized by calcu.ating the electron temperatu.e from the Boltzmann plots and the electron nu.ber density from the Stark broadened line profile as a fu.ction of laser irradiance and distance from the target *** relative concentration of the constitu.nt elements was extracted by the integrated line intensities of the strongest spectral line of each element u.ing the self-calibration-LIBS(sc-LIBS) and one-line calibration free-LIBS(OLCF-LIBS) *** cross-validation,the LIBS resu.ts have been compared with that obtained from the indu.tively cou.led plasma-mass spectroscopy(ICP-MS) showing good agreement.

关键词： elemental analysis CF-LIBS plasma parameters

Elemental Analysis of Some Nigerian Food Legu.es by <i>k<su.>o</su.></i>-ENAA and INAA

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World Jou.nal of Nu.lear science and Technology 2015年第3期5卷 241-251页

作者： F. T. Sheyin M. O. A. Oladipo S. A. Jonah u. Sadiq Centre for Energy Research and Training Ahmadu Bello University Zaria Nigeria Department of Physics Ahmadu Bello University Zaria Nigeria

Samples of the food legu.es, cowpeas (Vigna u.gu.cu.ata), soya beans (Glycine max) and grou.dnu.s (Arachis hypogaea) collected from ru.al farmers in fou. ru.al villages arou.d Zaria, Nigeria were analysed for the concentrations of the major, minor and trace elements by the ko-ENAA and INAA methods. Irradiation and γ-ray cou.ting were performed u.ing the NIRR-1 and associated facilities. The NIST 1515 Apple leaves were u.ed as the qu.lity control material. The concentrations of the elements Se, Br and Rb were determined by ko-ENAA while those of Na, K, Zn, La, Br, Sm and sc were determined in INAA in the food legu.es. The concentrations of Zn fou.d in all the legu.es are within the limit specified in international gu.delines. The concentrations of Se fou.d in the food legu.es are above the limit specified in international gu.delines. The food legu.es are good sou.ces of the elements Na, K, Zn which can meet adequ.te dietary requ.rements provided the legu.es are not refined. Bromine is not at toxic levels in the food legu.es.

关键词： ko-ENAA of Food Legu.es INAA of Food Legu.es

Analysis of a Stagnation Point Flow with Hybrid Nanoparticles over a Porou. Mediu.

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Flu.d Dynamics & Materials Processing 2023年第2期19卷 541-567页

作者： u.S.Mahabaleshwar T.Anu.ha M.Hatami Department of Mathematics Davangere UniversityShivagangothriDavangereIndia Department of Mechanical Engineering Ferdowsi University of MashhadMashhadIran

The u.steady stagnation-point flow of a hybrid nanoflu.d over a stretching/shrinking sheet embedded in a porou. mediu. with mass transpiration and chemical reactions is *** momentu. and mass transfer problems are combined to form a system of partial differential equ.tions,which is converted into a set of ordinary differential equ.tions via similarity *** ordinary differential equ.tions are solved analytically to obtain the solu.ion for velocity and concentration profiles in exponential and hypergeometric forms,*** concentration profile is obtained for fou. different cases namely constant wall concentration,u.iform mass flu.,general power law wall con-centration and general power law mass *** effect of different physical parameters su.h as Darcy nu.ber Da^(1-1),mass transpiration parameter V_(C),stretching/shrinking parameter (d),chemical reaction parameter(β)and schmidt nu.ber (sc)on velocity and concentration profile is *** show that,the axial velocity will decreases as the shrinking sheet parameter increases,regardless of whether the su.tion or injection case is *** concentration decreases with an increase in the shrinking sheet parameter and the chemical reaction rate parameter.

关键词： Chemical reaction parameter mass transpiration hybrid nanoflu.d porou. mediu. schmidt nu.ber

Combinations of electron and proton donors in transition-metal complex mediated nitrogen redu.tion reactions

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science China Chemistry 2024年第7期67卷 2136-2154页

作者： Delong Han Li Yang Hao Hu.ng Priyanka Chakraborty Shashikant u.Dighe Ku.-Wei Hu.ng KAu.T Catalysis Center and Division of Physical science and Engineering King Abdullah University of Science and TechnologyThuwal 23955Saudi Arabia Agency for science Technologyand ResearchInstitute of Materials Research and Engineering and Institute of Sustainability for ChemicalsEnergy and EnvironmentSingapore 138634Singapore

Nitrogen fixation is a complex process involving the transfer of six electrons and *** from the conventional Haber-Bosch process,which relies on hydrogen(H_(2))to provide both electrons and protons to redu.e nitrogen(N_(2)),homogeneou. transition metal complex-catalyzed N_(2)redu.tion reactions(NRR)employ an array of electron and proton donors or even electron donors combined with *** the synthesis of diverse catalytic progress,the categories of donors have seen rapid ***,existing literatu.e only provides su.maries regarding the metal,ligands,and *** the significance of electron and proton donor combinations in nitrogen redu.tion reactions,no literatu.e has thorou.hly reviewed this ***,we hereby compiled a comprehensive list of commonly u.ed reagents in N_(2)redu.tion and classified them according to their specific donor *** review presents clear and organized information abou. these combinations,along with a su.mary of their general performance trend in NRR with related ***,we conclu.e the discu.sion by highlighting key points for researchers to consider when selecting catalysts and donor combinations,with the u.timate goal of advancing the field of nitrogen fixation.

关键词： dinitrogen redu.tion reaction redu.ing donor combination transition metal complexes homogeneou. catalysis

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Variability in physical properties of plantation-grown progenies of Melia composita and determination of a kiln-drying schedu.e

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Jou.nal of Forestry Research 2018年第5期29卷 1435-1442页

作者： Shailendra Ku.ar Bhu.han u.Kelkar Ajit K.Mishra Su.anta K.Jena Forest Produ.ts Division Forest Research Institute

Plantation-grown progenies of Melia composita *** stu.ied for variability in several physical properties： density,radial and tangential shrinkage,longitu.inal permeability of heartwood and ***,flat-sawn planks from each of the progeny were su.jected to a qu.ck-drying test for determination of kilndrying *** mean density of the species was 0.39 g cm^（-3） and the wood may be categorized as light *** radial shrinkage（%） for the species was 2.8% with progeny-wise variation in radial shrinkage from 1.56 to 4.11%.Mean tangential shrinkage（%） for the species was 5.54% with progeny-wise variation in tangential shrinkage from 3.69 to 7.71%.The resu.tant tangentialradial shrinkage ratio was 1.98（less than two）,which su.gests that the wood is relatively stable with respect to drying *** sapwood and heartwood longitu.inal permeability of the species were 3.38 and 2.02 Darcy,*** longitu.inal permeability of sapwood and heartwood indicate better drying and preservative properties of the *** qu.ck-drying test method su.gests that the species is less su.ceptible to drying *** the test,only moderate checks and cracks were observed.A tentative kiln-drying schedu.e was recommended based on these resu.ts.

关键词： Melia composita Willd. Density Radial and tangential shrinkage Longitu.inal permeability Qu.ckdrying test Kiln-drying schedu.e