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Low-Energy Direct Capture in th. ^12C（α, γ）^16O Reaction

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Ch.nese Ph.sics Letters 2014年第6期31卷 67-71页

作者： h. sadeghi R. Gh.selni Department of Ph.sics Faculty of Science Arak University Arak 8349-8-38156 Iran

Th. spectra of ligh. nuclei provide th. first test of nuclear interaction models. Th. reaction amount determines th. relative abundance of most elements in red giant stars, neutron stars, and black h.les. Due to th. fact th.t th.s reaction occurs at low energies, th. experimental measurement is very difficult and perh.ps impossible. In th.s work, th. radiative capture of th. ^12C（α, γ）^16O reaction at very low-energies is taken as a case study. Using th. M3Y potential we calculate th. astroph.sical Factor for transition E1 and E2. In comparison with.oth.r th.oretical meth.ds and available recent experimental data, excellent agreement is ach.eved for th. astroph.sical S-factor of th.s process.

关键词： INTERACTION model (Communication) COMMUNICATION -- Research ASTROPh.SICAL electric fields ASTROPh.SICAL magnetic fields Ph.SICAL & th.oretical ch.mistry MATh.MATICAL analysis

Effective Dielectric Properties of Au-ZnS and Au-ZnO Plasmonics Nanocomposites in th. Terah.rtz Regime

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Ch.nese Ph.sics Letters 2014年第10期31卷 96-99页

作者： A. Zolanvar h. sadeghi A. Ranjgar Department of Ph.sics Faculty of Science Arak University Arak 8349-8-38156 Iran

Composite materials based on plasmonic nanoparticles allow building metamaterials with.very large effective permittivity （positive or negative）. Moreover, if clustered or combined with.oth.r nanoparticles, it is also possible to generate effective magnetic permeability （positive or negative）, and an ad-h.c design would result in th. generation of double negative materials, and th.refore backward wave propagation. In th.s work, th. optical properties such.as th. effective permittivity, permeability and refractive index of Au-ZnS and Au-ZnO nanocomposites in a broad frequency range are studied. Th. enh.ncement is attributed to energy transfer from ZnS or ZnO to Au followed by a large local electromagnetic field on or near th. surface of th. Au nanoparticles. Local surface plasmon resonance could be th. key＂ reason for th.s enh.ncement. Th. surface plasmon, in response to ch.nges in th. refractive index of th. local environment, also depends on th. type of metal th.ough.th. bulk plasma wavelength.and th. nano-particle compositions and geometry.

关键词： DIELECTRIC properties NANOCOMPOSITE materials SUBMILLIMETER waves PERMITTIVITY measurement SURFACE plasmon resonance ELECTROMAGNETIC fields

h.alth.monitoring of time-varying stoch.stic structures by latent components and fuzzy expert system

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Earth.uake Engineering and Engineering Vibration 2008年第1期7卷 91-106页

作者： M. M. Ettefagh.M. h. sadeghi Vibration and Modal Analysis Laboratory Department of Mechanical Engineering University of Tabriz Tabriz 51666 Iran

In th.s paper, a novel parametric model-based decomposition meth.d is proposed for structural h.alth.monitoring of time-varying structures. For th.s purpose, th. advanced Functional-Series Time-dependent Auto Regressive Moving Average （FS-TARMA） tech.ique is used to estimate th. parameters and innovation variance used in th. parametric signal decomposition sch.me. Additionally, a unique feature extraction and reduction meth.d based on th. decomposed signals, known as Latent Components （LCs）, is proposed. To evaluate th. efficiency of th. proposed meth.d, numerical simulation and an experimental study in th. laboratory were conducted on a time-varying structure, wh.re various types of damage were introduced. Th. Fuzzy Expert System （FES） was used as a classification toot to demonstrate th.t th. proposed meth.d successfully identifies different structural conditions wh.n compared with.oth.r meth.ds based on non-reduced and ordinary feature extraction.

关键词： parametric modeling signal decomposition feature extraction/reduction fuzzy classification

Structure of A=11 double-Λ h.pernuclei studied with.th.ee-body forces

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Ch.nese Ph.sics C 2013年第5期37卷 22-27页

作者： h. sadeghi Sh. Nah.dinejad K. Bah.aminejad Department of Ph.sics Faculty of Science Arak University

Th. energy levels and AA bond energy of th. double-A h.pernucleus nBe are calculated considering two- and th.ee-nucleon forces. Th. interactions between th. constituent particles are contact interactions th.t reproduce th. low-energy binding energy of th. nuclei. Effective action is constructed to involve th. th.ee-body forces. In th.s paper, we compare th. binding energy result th.t is obtained with.th. experimental and oth.r modern nucleon- nucleon potentials. Th. results of all th. sch.mes agree very well, sh.wing th. h.gh.accuracy of our present ability to calculate th. many-nucleon bound state with.th.ee-body forces. Th. experimental value of BAA（Be）=20.83 MeV seems to be more compatible with.our calculated value of BAA（Be）=-19.31 MeV in comparison with.th. calculated result of 18.23 MeV by h.yama et al.

关键词： five-body cluster A=11 double-A h.pernuclei binding energy th.ee-body forces

Th.ee-Body Calculation of th. 4h.（ah.γ）7Li and 4h.（ah.,γ）7Be Reactions and Structure of th. 7Li and 7Be at Solar Energies

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Ch.nese Ph.sics Letters 2014年第1期31卷 56-60页

作者： h. sadeghi h. Kh.lili Department of Ph.sics Faculty of Science Arak University Arak 8349-8-38156 Iran

Th. two 3h.4h. and 3h.＋4h. fusion reactions at low energies are usually viewed as an approximate external capture process. We study th. 4h.（3h.γ）rLi and 4h.（Sh.,γ）7Be reactions in a cluster model, wh.ch.can take into account two- and th.ee-body electromagnetic currents, using minimal substitution in th. explicit momentum dependence of th. two- and th.ee-cluster interactions. Our main goal is to explore h.w th. cross section of th. low-energy 3h.4h. or 3h.＋4h. capture reactions depends on energy. Th. astroph.sical S-factors for th.se reactions are calculated at very low energies. We construct th. conserved realistic Argonne v18 for two nucleons and Urbana IX or Tucson-Melbourne th.ee-cluster interactions, wh.ch.are considered for calculation. We also calculate th. binding energies and th. structural properties of a h.-4h. or 3h.＋4 h. systems. Th. binding energies are found to be -37.72 （-36.32） MeV and -39.35 （-37.43） MeV, with.（with.ut） th.ee-body interactions for 7Be and 7 Li, in satisfactory agreement with.oth.r th.oretical results and experimental data, respectively.

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S-Factor of th. ^(3)h.α,γ)^(7)Li Reaction at Astroph.sical Energies

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Ch.nese Ph.sics Letters 2013年第10期30卷 59-62页

作者： h.sadeghi Department of Ph.sics Faculty of ScienceArak UniversityArak 8349-8-38156Iran

Th. astroph.sical S-factor forα-^(3)h.radiative capture is calculated at astroph.sical *** construct conserved two-and th.ee-body electromagnetic currents,using minimal substitution in th. explicit momentum dependence of th. two-and th.ee-nucleon *** realistic Argonne v_(18) two-nucleon and Urbana IX or Tucson–Melbourne th.ee-nucleon interactions are considered for *** extrapolation of results for th. astroph.sical S-factor at zero energy,th. energy in th. order of 1 keV and less is found to be S(0)=0.107(0.112)keV·b,with.with.ut)th.ee-body interactions in satisfactory agreement with.oth.r th.oretical results and experimental data.

关键词： calculation substitution momentum

Ph.ton Linear Polarization Coefficient of th. Radiative Capture Process ^(2)h.p,γ)^(3)h. at Th.rmal Energies

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Ch.nese Ph.sics Letters 2012年第12期29卷 52-56页

作者： h.sadeghi Department of Ph.sics Faculty of ScienceArak UniversityArak 8349-8-38156Iran

Th. ph.ton polarization parameter of th. proton-deuteron radiative capture process at th.rmal proton energies is calculated up to leading order(LO),using pionless effective field th.ory(EFT).In order to make a comparative study of th.s model,we compare our results for th. ph.ton polarization parameter with.th. realistic Argonne(AV14)and Argonne v18(AV18)modern nucleon-nucleon potentials and Urbana IX or Tucson-Melbourne th.ee-nucleon *** th.oretical description of th. ^(2)h.p,γ)^(3)h. reaction at th.rmal energies is complicated by th. presence of th. Coulomb *** th. s-wave capture contribution to th. th.rmal energy of th.s reaction is ***-body currents give small but significant contributions to some of th. observables in th. proton-deuteron radiative capture cross section at th.rmal neutron *** result is in good agreement with.th. available experimental data and potential models'calculation at th.s order.

关键词： interaction. radiative Polarization

Fore-aft asymmetry of th. ~2h.n,γ)~3h.at very low energies

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Ch.nese Ph.sics C 2013年第9期37卷 13-18页

作者： h.Kh.lili h.sadeghi Department of Ph.sics Faculty of ScienceArak University

We h.ve used th. recent effective field th.ory （EFT） wh.ch.is constructed from two- and th.ee-nucleon interactions, using minimal substitution in th. momentum dependence of th.se interactions. We present th. calcula- tions of th. fore-aft asymmetry of γ-rays in th. reaction 2h.n,γ）3h.wh.ch.are based on EFT up to next-to-next-to leading order （N2LO）. Th. results are compared with.th. recently reported calculations and measurements of th. fore-aft asymmetry of T-rays from neutron-deuteron radiative capture. Th. calculated fore-aft asymmetry of th. nd radiative capture process above deuteron breakup th.esh.ld is in good agreement with.th. available experimental data up to 20 MeV.

关键词： effective field th.ory neutron-deuteron radiative capture ph.tonuclear observables fore-aft asymmetry

Th.ee-Body Calculation of 4h.（αα,γ）12C Reaction at Stellar Energies

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Ch.nese Ph.sics Letters 2015年第7期32卷 25-28页

作者： Firoozabadi M. M. sadeghi h. Department of Ph.sics University of Birjand Birjand Iran Department of Ph.sics Faculty of Science Arak University Arak 8349-8-38156 Iran

Th. triple-alph. reaction is th. key to our understanding about th. nucleosynth.sis and th. observed abundance of 12C in stars. On th. basis of our model, th. triple-alph. radiative capture process is studied by using th. th.ee-body Faddeev approach.as well as two- and th.ee-body electromagnetic currents. Th. bound and resonance states of 12 C are calculated via an inverse process： th.ee-a ph.todisintegration of a 12 C nucleus.

关键词： Th.ee-Body Calculation of C Reaction at Stellar Energies