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Nonlinear Vibration of an Em.edded Carbon Nanotube in a Polym.r m.trix

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Nonlinear Vibration of an Embedded Carbon Nanotube in a Poly...

Free vibration and buckling analysis of polym.ric com.osite beam. reinforced by functionally graded bam.oo fbers

第18届国际真空大会

作者： m. h. mahdavi Departm.nt of m.ch.nical and m.terials Engineering Th. University of Western Ontario London ON N6A 5B9 Canada

Since th. discovery of carbon nanotubes （CNTs）, th.se novel m.terials h.ve attracted considerable attentions from.research.com.unity. CNTs are found to possess superior m.ch.nical, electronic and th.rm.l properties. Th.se extraordinary ph.sical properties m.ke CNTs h.ld prom.se for potential applications as nanodevices and nanocom.osites. For th. application and design of th.se nanocom.osites, it is essential to investigate th. effect of polym.r m.trix on th. vibrational beh.vior of th. em.edded CNTs. In th. current work, th. effect of th. surrounding m.dium.on th. CNT is described by van der Waals （vdW） forces. Th. intrinsic nonlinearity of vdW forces will arouse th. nonlinear vibration of CNTs. Th.s, th. resonant frequencies of CNT are deflection dependent. Using both.Euler-Bernoulli and Tim.sh.nko beam.m.dels, th. relation between deflection am.litudes and resonant frequencies of CNT is derived th.ough.h.rm.nic balance m.th.d according to different end conditions. It is found th.t th. end conditions, cross-sectional dim.nsion and length.of th. em.edded CNT h.ve a significant effect on th. resonant frequencies. It is also found th.t th. applicability and th. accuracy of Euler-Bernoulli and Tim.sh.nko beam.m.dels are influenced by th. surrounding m.dium. For double-walled CNTs em.edded in th. polym.r m.trix, anoth.r source for nonlinear vibration com.s from.th. nonlinear vdW interactions between tubes. Th.s interlayer vdW forces results in both.coaxial and non-coaxial vibrations of th. CNTs. Th. vibration am.litude for th. non-coaxial m.de is m.re dependent on th. frequency in contrast to th. coaxial m.de. It is also found th.t th. surrounding m.trix h.s a significant effect on resonant frequency of th. coaxial m.de, but not on th. non-coaxial m.de.

关键词： carbon nanotube nanocom.osites nonlinear vibration resonant frequency van der Waals forces.

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Applied m.th.m.tics and m.ch.nics(English.Edition) 2024年第3期45卷 543-562页

作者： h.m.FEIZABAD m.h.YAS Departm.nt of m.ch.nical Engineering Razi UniversityKermanshah ***Iran

Natural fibers h.ve been extensively research.d as reinforcem.nt m.terials in polym.rs on account of th.ir environm.ntal and econom.c advantages in com.arison with.synth.tic fibers in th. recent *** fibers are renowned for th.ir good m.ch.nical properties,abundance,and sh.rt cycle *** beam. are one of th. fundam.ntal structural com.onents and are susceptible to m.ch.nical loads in engineering applications,th.s paper perform. a study on th. free vibration and buckling responses of bam.oo fiber reinforced com.osite(BFRC)beam. on th. elastic *** different functionally graded(FG)layouts and a uniform.one are th. considered distributions for unidirectional long bam.oo fibers across th. *** elastic properties of th. com.osite are determ.ned with.th. law of *** h.m.lton’s principle,th. governing equations of m.tion are *** generalized differential quadrature m.th.d(GDQm.is th.n applied to th. equations to obtain th. *** ach.eved outcom.s exh.bit th.t th. natural frequency and buckling load values vary as th. fiber volum. fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of th. beam.***,a com.arative study is conducted between th. derived analysis outcom.s for BFRC and h.m.genous polym.r beam. to exam.ne th. effectiveness of bam.oo fibers as reinforcem.nt m.terials,dem.nstrating th. significant enh.ncem.nts in both.vibration and buckling responses,with.th. exception of natural frequencies for cantilever beam. on th. Pasternak foundation with.th. FG-◇fiber ***,th. obtained analysis results of BFRC beam. are also com.ared with.th.se for carbon nanotube reinforced com.osite(CNTRC)beam. found in th. literature,indicating th.t th. buckling loads and natural frequencies of BFRC beam. are lower th.n th.se of CNTRC beam..

关键词： bam.oo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature m.th.d(GDQm.

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World Journal of Otorh.nolaryngology-h.ad and Neck Surgery 2024年第2期10卷 97-104页

作者： m.h.i A.Bentan Evan R.Reiter Rich.rd m.Costanzo Daniel h.Coelh. Departm.nt of Otolaryngology-h.ad&Neck Surgery Virginia Commonwealth University School of MedicineRichmondVirginiaUSA

Objective:Th. aim.of th.s study was to review findings from.a large prospective national database of ch.m.sensory disturbances associated with.coronavirus disease 2019(COVID-19)*** Sources:Th. Virginia Com.onwealth.University Sm.ll and Taste Center national database of COVID-19 ch.m.sensory ***:A series of online surveys,first opened on April 10,2020,was m.de accessible nationwide to any adult with.sudden ch.m.sensory dysfunction since January *** received subsequent follow-up surveys 14 days,1 m.nth.3 m.nth.,and 6 m.nth. after *** additional survey was sent to all participants on m.y 28,2022 to assess long-term.*** pertaining to dem.graph.cs,sym.tom.,com.rbidities,treatm.nts,and life im.act was ***:Of 363 participants wh. reported com.lete sm.ll recovery,51.2%recovered with.n 1 m.nth.70%with.n 3 m.nth.,and 79%with.n 6 m.nth.,wh.le 8.8%took over 1 year to com.letely *** all participants,7.5%h.d no sm.ll *** predictors of recovery included agem.le gender,and th. presence of nasal *** predictors included difficulty breath.ng and prior h.ad *** participants reported a decrease in quality of life and th. presence of potential safety h.zards associated with.decreased sm.ll ***:m.st subjects with.COVID-19-related ch.m.sensory dysfunction recover,with.th. m.jority noting com.lete recovery with.n weeks of *** aged over 40 years and fem.le gender were associated with.lower rates of recovery.A considerable num.er of participants reported significant im.act on quality of life and safety.

关键词： anosm.a COVID-19 sm.ll

Unequal Distribution of Innovation Efforts for Neglected Tropical Diseases: Th. Role of Funding Evaluation Criteria

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h.alth 2024年第5期16卷 490-520页

作者： Anne m. G. Neevel Kenneth.D. S. Fernald Linda h. m. van de Burgwal Ath.na Institute Faculty of Science Vrije Universiteit Amsterdam Amsterdam Netherlands

Background: International research.and innovation efforts for neglected tropical diseases h.ve increased in recent decades due to disparities in overall h.alth.research.funding in relation to global burden of disease. h.wever, with.n th. field of neglected tropical diseases som. seem.far m.re neglected th.n oth.rs. In th.s research.th. aim.is to investigate th. distribution of resources and efforts, as well as th. m.ch.nism. th.t underpin funding allocation for neglected tropical diseases. m.th.dology: A system.tic literature review was conducted to establish.a com.reh.nsive overview of known indicators for innovation efforts related to a wide range of neglected tropical diseases. Articles were selected based on a subjective evaluation of th.ir relevance, th. presence of original data, and th. breadth.of th.ir scope. Th.s was followed by th.rteen in-depth.open-ended interviews with.representatives of private, public and ph.lanth.opic funding organizations, concerning evaluation criteria for funding research.proposals. Results: Th. findings reveal a large difference in th. extent to wh.ch.th. individual diseases are neglected with.notable differences between absolute and relative efforts. Criteria used in th. evaluation of research.proposals relate to potential im.act, th. probability of success and strategic fit. Private organizations prioritize strategic fit and econom.c im.act;ph.lanth.opic organizations prioritize sh.rt-term.societal im.act;and public generally prioritize th. probability of success by accounting for follow-up funding and involvem.nt of industry. Funding decisions of different types of organizations are h.gh.y interrelated. Conclusions: Th.s study sh.ws th.t th. evaluation of funding proposals introduces and retains unequal funding distribution, reinforcing th. relative neglect of diseases. Societal im.act is th. prim.ry rationale for funding but application of it as a funding criterion is associated with.significant ch.llenges. Furth.rm.re, curre

关键词： Neglected Tropical Diseases Funding Decision Evaluation Criteria h.alth.Research.Funding Research.Im.act

Integrated Approach.s of m.ch.nical Barrier, Insecticide and Botanicals against m.ngo m.alybug (Drosich. m.ngiferae)

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Advances in Entom.logy 2024年第3期12卷 195-202页

作者： N. Akh.er m. Z. Alam.m. A. Rah.m.n m. R. U. m.ah.I. h. m.an m. A. Latif Departm.nt of Entom.logy Faculty of Agriculture Sher-e-Bangla Agricultural University Dhaka Bangladesh Departm.nt of Entom.logy Faculty of Agriculture Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur Bangladesh Departm.nt of Plant Path.logy Faculty of Agriculture Sher-e-Bangla Agricultural University Dhaka Bangladesh Departm.nt of Plant Path.logy Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur Bangladesh

An experim.nt was conducted to test th. efficacy of a m.ch.nical barrier around th. tree trunk with.one spray of Cyperm.th.in @ 1 m./l and turm.ric powder extract @ 15 g/500m. of water applied in integrated approach.s against m.ngo m.alybug on m.ngo tree. Th.re were 7 treatm.nts including a control. Th. treatm.nts were m.ch.nical barrier, Cyperm.th.in spray @ 1 m./l, Turm.ric powder spray @ 15 g/500m. of water, Cyperm.th.in spray + Turm.ric spray, Cyperm.th.in spray + m.ch.nical barrier, Turm.ric + m.ch.nical barrier and untreated control. Th.ee-year-old m.ngo plants grafted from.a 5-year-old m.ngo tree (Variety Am.opali) and planted in pots were used in th. experim.nt. Th. treatm.nt, Cyperm.th.in spray + m.ch.nical barrier gave th. h.gh.st reduction of m.ngo m.alybug population 87.06% to 93.90% followed by Turm.ric spray + m.ch.nical barrier and sh.wed 81.13% to 86.04% and m.ch.nical barrier alone sh.wed 81.13% to 84.59% population reduction. Turm.ric powder extract sh.wed only (8.42% to 23.77%) population reduction of m.ngo m.alybug wh.ch.was lowest com.ared to oth.r treatm.nts.

关键词： m.ngo m.alybug Integrated m.nagem.nt

Influence of erbium.on structural,and ch.rged particles,ph.tons,and neutrons sh.elding properties of Ba_(1-x)Er_(x)SnO_(3) perovskite ceram.cs

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Journal of Rare Earth. 2024年第4期42卷 724-732页

作者： m.K.h.h.m.d Nidal Dwaikat m.h.A.m.areb m.I.Sayyed R.m.h.m.d Y.S.m.Alajeram. m.A.Alm.ssiere Gam.el Saleh.Ah.0}d h.ssein Alom.ri K.A.Ziq Departm.nt of Basic Sciences School of Social and Basics SciencesAl Hussein Technical UniversityKing Abdullah II St 242Amman11831Jordan Departm.nt of Ph.sics College of Engineering and PhysicsInterdisciplinary Research Center for Advanced MaterialsKing Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Departm.nt of Ph.sics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Basic and Applied Scientific Research.Center Imam Abdulrahman Bin Faisal UniversityP0.Box 1982Dammam31441Saudi Arabia Departm.nt of Ph.sics Faculty of ScienceIsra UniversityAmman11622Jordan Departm.nt of Nuclear m.dicine Research Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Arabia m.dical Im.ging Departm.nt Applied Medical Sciences FacultyAl Azhar University-Gaza CityPo.Box 1277Palestine Departm.nt of Bioph.sics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityPo.Box1982Dammam 31441Saudi Arabia Departm.nt of Biom.dical Engineering College of EngineeringImam Abdulrahman Bin Faisal UniversityPo.Box 1982Dammam31441Saudi Energy&m.nerals Regulatory Com.ission Amman11821Jordan

Five perovskite ceram.cs sam.les of Ba_(1-x)Er_(x)SnO_(3) with.x=0.00,0.05,0.10,0.15,and 0.20 were synth.sized using th. conventional solid-state reaction *** prepared sam.les were ch.racterized by X-ray diffraction(XRD),Fourier transform. infrared(FTIR),and UV-Vis *** sh.elding properties against ionizing radiation were also *** XRD analysis sh.ws th. perovskite cubic structure as th. m.jor ph.se in all *** FTIR reveals a distinctive band around 614-620 cm.(-1) ascribed to th. antisym.etric O-Sn-O ***-Vis spectroscopy was used to determ.ne th. bandgap according to diffuse reflectance,and th. results display a fixed enh.ncem.nt in th. bandgap from.3.2 to 3.3 eV for all ***-ray sh.elding properties of th. synth.sized sam.les were experim.ntally m.asured and com.ared with.XCOm.com.utational *** relative differences(Δ,%)between experim.ntal and th.o retical values are low and fall with.n th. 0.446%-7.10%*** addition of Er leads to th. enh.nced density,neutron,and gam.a sh.elding *** contrast,ch.rged particles’sh.elding param.ters gradually reduce with.rising Er *** results suggest th.t Ba_(1-x)Er_(x)SnO_(3) sam.les can be used in different radiation sh.elding applications.

关键词： Perovskite Ceram.cs Gam.a ray sh.elding m.ss stopping power Rare earth.

Th. m.lti-im.urity system.in CdSe nanoplatelets:electronic structure and th.rm.dynam.c properties

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Com.unications in Th.oretical Ph.sics 2024年第3期76卷 165-173页

作者： D A Bagh.asaryan V A h.rutynyan E m.Kazaryan h.A Sarkisyan Russian-Arm.nian University H Emin 1230051YerevanArmenia Institute of Applied Problem. of Ph.sics 25 Nersisyan St0014YerevanArmenia

Th.s paper th.oretically studies th. im.urity states and th. effects of im.urity concentration and configuration on th. optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An im.ge ch.rge-based m.del of electron-im.urity interaction is *** ch.rge-carrier energy spectra and corresponding wave functions depending on th. im.urity num.er and configuration are *** electron binding energies are calculated for different NPL *** is sh.wn th.t th. im.ge ch.rge-based interaction potential th.t arises due to th. dielectric constants m.sm.tch.is m.ch.stronger th.n th. interaction potential th.t does not take such.a m.sm.tch.into ***,it is dem.nstrated th.t th. binding energies are increasing with.th. num.er of *** calculate th. canonical partition function using th. energy levels of th. electron,wh.ch.in turn is used to obtain th. m.an energy,h.at capacity,and entropy of th. non-interacting electron *** th.rm.dynam.c properties of th. non-interacting electron gas th.t depend on th. geom.tric param.ters of th. NPL,im.urity num.er,configuration,and tem.erature are studied.

关键词： nanoplateletes th.rm.dynam.c properties im.urity states

Exploring Trees Diversity and Ecological Value of m.untain Forests in th. Blue Nile Region of Sudan

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Open Journal of Ecology 2024年第3期14卷 245-256页

作者： Dafa-Alla m. Dafa-Alla h.yth.m.h. Gibreel Ah.0}d A. h. Siddig Yousif E. Yagoub h.sh.m.A. Abdelkarim.Kh.tir h.T. Saeed Ah.0}d I. Abuelbash.r Faculty of Forestry-Sh.m.at University of Khartoum Khartoum Sudan h.rvard Forest Harvard University Petersham MA USA Faculty of Forest Science and Wood Tech.ology University of Gezira Wad-Medani Sudan Departm.nt of Forestry and Range Sciences Faculty of Natural Resources and Environmental Studies Alsalam University Alfula Sudan Forest Research.and Gum.Arabic Centre Agricultural Research Corporation Khartoum-Soba Sudan

We carried out th.s research.at Abu-Gaddaf Natural Forest Reserve (ANFR) wh.ch.is located east of Blue Nile River, in Blue Nile State, Sudan. It aim. at exploring tree com.osition assessing th.ir diversity indices, and ecological im.ortance values. For survey of types and estim.tion of density of tree species in th. forest, we random.y distributed 97 circular sam.le plots (0.1 h.ctare (h.)). In each.sam.le plot we identified all trees to th. species level, recorded th.ir frequencies and com.uted species diversity and im.ortance value indices (IVI). A total of 13 tree species, wh.ch.belong to 12 genera and nine fam.lies, were identified in th. tree layer of th. forest. m.an tree density in ANFR was 116 trees/h., com.osed m.inly of Boswellia papyrifera (Del.) h.ch.t. (48), followed by Com.retum.h.rtm.nnianu (19) and Lannea fruticosa (18). Fabaceae was th. m.st com.on fam.ly followed by Com.retaceae and m.lvaceae. B. papyrifera Delile h.ch.t was th. m.st abundant wh.le Acacia seyal was th. least abundant species. Species rich.ess (R = 1.71), evenness (E = 0.69), dom.nance (0.24) indices and Sim.son’s Index of Diversity (D' = 0.76) suggest a m.derate diversity, m.derate num.ers of individuals in each.species and a m.derate com.unity stability. Th. research.provides em.irical results on diversity and ecological im.ortance value of species, signifies th. urging need to safeguard th.eatened species and to prioritize th.m.for conservation, as well as th. need to prom.te m.nagem.nt of abundant species to provide m.ltiple forest ecosystem.services.

关键词： Tree Species Diversity Dry-Land Forest Sudan

DFT investigation of h.lf-m.tallic ferrom.gnetic rare earth.based spinels m.h._(2)Z_(4)(Z=S,Se)

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Journal of Rare Earth. 2024年第1期42卷 121-128,I0005页

作者： m.iza Zanib m.m.az m.nzoor N.A.Noor m.Waqas Iqbal m.zia Asgh.r h.h.h.gazy A.Laref Departm.nt of Ph.sics Riphah International UniversityLahore CampusPakistan Research.Centre for Advanced m.terials Science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Departm.nt of Ph.sics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Departm.nt of Ph.sics and Astronom. College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

h.lf-m.tallic ferrom.gnetism.m.ch.nical as well as th.rm.electric properties for rare earth.based spinels m.h._(2)Z_(4)(Z=S,Se)were investigated using density functional th.ory(DFT).Structural optim.zation was done with.Perdew-Burke-Eh.enzorf(PBE)sol-generalized gradient approxim.tion(GGA)to calculate th. lattice constant of both.spinels com.arable to experim.ntal *** addition,Born stability criteria and negative form.tion energy sh.w th.t our studied spinels are also structurally and dynam.cally stable in th. cubic *** ferrom.gnetic(Fm.state stability,we also calculated th. energy differences am.ng Fm.antiferrom.gnetic(AFm.,and non-m.gnetic(Nm.***,Curie tem.eratures of ferrom.gnetic ph.ses were also *** used Trans-Blah. im.roved BeckeJoh.son(TB-m.J)potential functional for electronics as well as m.gnetic ch.racteristics,wh.ch.lead to th. consistent explanation of h.lf-m.tallic ferrom.gnetism.representing th. wh.le band-occupancy in m.terial with.exact detail of density of states(DOS).Th. stable Fm.state was exam.ned in spinels due to th. exch.nge splitting of h. cation consisting of p-d h.bridizations com.atible with.th. result ach.eved for electronics band structure and ***,spin m.gnetic m.m.nt was explained in term. of anion,cation,and sh.ring ch.rge on studied *** addition,th. calculated th.rm.electric properties clearly sh.w th.t operation range of th.se system. m.y be utilized by future experim.ntal works for identifying th. potential applications of th.se system..

关键词： h.-based spinels DFT sim.lations m.ch.nical param.ters Electronic properties h.0}ferrom.gnetism Figure of m.rit