Surface Plasmons and Optical Properties of TiO_(2)/X(X=Au and Ag)Nanostructure Thin Films

TiO_(2)/X(X=Au and Ag)nanolayers are fabricated by depositing TiO_(2)films using rf magnetron sputtering on thin quartz substrates embedded with Au and Ag nanoparticles.Enhancement of light absorption of the nanostructural layers is observed.These plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of light.The light absorption enhancement of synthesized structure in comparison to TiO_(2)is originated from near-field enhancement caused by the plasmonic effect of metallic nanoparticles,which can be demonstrated by the optical absorption spectra.We show that plasmon modes can exist for the infrared region of the optical spectrum.Also,we analyze the optical properties of the metal-insulator films,in order to clarify the role of metal inclusions in the TiO_(2)dielectric matrix.Optical band gaps of the nanolayer films are calculated by using Tauc’s relation,and the𝑜values of optical band gaps with the variation composition are found from 1.80 to 3.69eV.Band gap narrowing and absorption in the visible spectral region induced by the incorporation of TiO_(2)/X(X=Au and Ag)nanolayers enable the design of nanostructured thin films to be achieved for photocatalysts and solar energy converters.

九州背弧冲绳海槽东北缘附近地幔顶层层析成像的低速异常

用联合反演三维速度结构与震源参数的方法确定日本西南部九州背弧层析图象。成像中使用的是从日本西部到中国东部广大区域内305个地震台记录的2736个地方震的初至到时资料。同时补充使用了357个远震的到时。在北纬30°～34°和东经128°～132°范围至少深达150km 范围内,我们得到了高分辨率的地幔顶层的 P 波层析图象。反演结果揭示出九州岛以西近海40～100km 深度范围内有一个大的强低速带。这种特征可能是由延展的冲绳海槽东北缘地区热地幔上涌产生的部分熔融引起的。

S-Factor of the ^(3)H(α,γ)^(7)Li Reaction at Astrophysical Energies

The astrophysical S-factor forα-^(3)H radiative capture is calculated at astrophysical energies.We construct conserved two-and three-body electromagnetic currents,using minimal substitution in the explicit momentum dependence of the two-and three-nucleon interactions.The realistic Argonne v_(18) two-nucleon and Urbana IX or Tucson–Melbourne three-nucleon interactions are considered for calculation.By extrapolation of results for the astrophysical S-factor at zero energy,the energy in the order of 1 keV and less is found to be S(0)=0.107(0.112)keV·b,with(without)three-body interactions in satisfactory agreement with other theoretical results and experimental data.

Photon Linear Polarization Coefficient of the Radiative Capture Process ^(2)H(p,γ)^(3)He at Thermal Energies

The photon polarization parameter of the proton-deuteron radiative capture process at thermal proton energies is calculated up to leading order(LO),using pionless effective field theory(EFT).In order to make a comparative study of this model,we compare our results for the photon polarization parameter with the realistic Argonne(AV14)and Argonne v18(AV18)modern nucleon-nucleon potentials and Urbana IX or Tucson-Melbourne three-nucleon interactions.The theoretical description of the ^(2)H(p,γ)^(3)He reaction at thermal energies is complicated by the presence of the Coulomb interaction.Only the s-wave capture contribution to the thermal energy of this reaction is calculated.Three-body currents give small but significant contributions to some of the observables in the proton-deuteron radiative capture cross section at thermal neutron energies.Our result is in good agreement with the available experimental data and potential models'calculation at this order.

Plasmonic Nanostructured Electromagnetic Materials

We study the materials that are composed of metals and insulators.These plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of light.A theoretical model is developed to simulate the refractive index of these nano-structured electromagnetic materials which support surface plasmon resonances.Factors contributing to the refractive index sensitivity are explored phenomenologically.Particles with size parameters smaller by much less than 1 have optical properties accurately predicted by the quasi-electrostatic theory while particles with larger size parameters necessitate electrodynamics.We simulate a type of refractive index material composed of metal and insulating dielectric nano-spheres,which are able to sustain the propagation of infrared or visible frequency electromagnetic waves known as surface plasmon polaritons.

Fore-aft asymmetry of the ~2H(n,γ)~3H at very low energies

We have used the recent effective field theory （EFT） which is constructed from two- and three-nucleon interactions, using minimal substitution in the momentum dependence of these interactions. We present the calcula- tions of the fore-aft asymmetry of γ-rays in the reaction 2H（n,γ）3H which are based on EFT up to next-to-next-to leading order （N2LO）. The results are compared with the recently reported calculations and measurements of the fore-aft asymmetry of T-rays from neutron-deuteron radiative capture. The calculated fore-aft asymmetry of the nd radiative capture process above deuteron breakup threshold is in good agreement with the available experimental data up to 20 MeV.

Astrophysical S-factor of the d（p,γ）~3 He process by effective field theory

We summarize the recent effective field theory （EFT） studies of low-energy electroweak reactions of astrophysical interest, relevant to big-bang nucleosynthesis. The zero energy astrophysical S（0） factor for the thermal proton radiative capture by deuteron is calculated with pionless EFT. The astrophysical S（0） factor is accurately determined to be S（0）=0.243 eV·b up to the leading order （LO）. At zero energies, magnetic transition M1 gives the dominant contribution. The M1 amplitude is calculated up to the LO. A good, quantitative agreement between theoretical and experimental results is found for all observables. The demonstrations of cutoff independent calculation have also been presented.

Astrophysical S-factor of the ^(12)C(α, γ)^(16)O reaction at solar energies

The astrophysical S-factor of the 4He＋12C radiative capture is calculated in the potential model at the energy range 0.1-2.0 MeV. Radiative capture 12C（α,γ） 16O is extremely relevant for the fate of massive stars and determines if the remnant of a supernova explosion becomes a black hole or a neutron star. Because this reaction occurs at low energies, the experimental measurements are very difficult and perhaps impossible. In this paper, radiative capture of the 12C（α,γ） 16O reaction at very low energies is taken as a case study. In comparison with other theoretical methods and available experimental data, good agreement is achieved for the astrophysical S-factor of this process.