An, J. M.Lin, H.Pun, E. Y. B.Li, D. S....
6页查看更多>>摘要：Newly developed glass system H3BO3-K2CO3-MgO-TeO2-ZnO-AgNO3 (HKMTZA) was synthesized by high temperature melting method for gamma and neutron shielding. The parameters of gamma and neutron attenuation are computerized utilizing Phy-X/PSD and for photon energies ranging between 15 KeV and 15 MeV. The newly developed tool is used to calculate the shielding parameters such as mass attenuation coefficient (mu/rho), relative parameters effective atomic number (Z(eff)), half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and fast neutrons (Sigma(R)). Meanwhile, Sigma(R) is enabled to assess the capabilities of the neutron shielding. Because of Ag element which has high atom number, HKMTZA6 has highest Z(eff) and lowest HVL, TVL. The results of this research revealed that Sigma(R) of this HKMTZA glass system increases with the improving of AgNO3 and the studied glass system possess higher Sigma(R) value, contrasting with T70V27Z3 glass. And it is closed to the leaded brass alloy (LB), and TeO2-B2O3 (TB), illustrating that the HKMTZA glass system possesses excellent properties of neutron shielding.
原文链接:
NSTL
Elsevier
Seto, G.Kpadonou, A.Yessoufou, R.Albayrak, E....
9页查看更多>>摘要：We have used the Oguchi approximation to study the effects of longitudinal crystal (D) and longitudinal external magnetic (h) fields on the mixed spin -(5/2, 1/2) anisotropic Heisenberg model. The thermal variations of sublattice and total magnetizations are exploited in detail for given values of D, exchange anisotropy parameter (triangle) and coordination numbers z = 3,4 and 6 when h = 0.0. Thus, the phase diagrams are constructed on the planes of (D/J, k(B)T/J) and (triangle, k(B)T/J). In this case, it is found that the model presents either first-or second order phase transitions as well as tricritical points. In the presence of magnetic field, the hysteresis loops of the model are also analyzed and it was found that the coercive field and remanent magnetization decrease as the temperature increases and increase as the crystal field or the exchange anisotropy increases.
原文链接:- NSTL
- Elsevier
Zidan, T. A.El-Menyawy, E. M.El-Shabaan, M. M.
10页查看更多>>摘要：Synthesis of azo dye, 4-[2(3-acetylphenyl) diazenyl]-3,5-dimethylphenol (ADD), is presented. The structural, linear optical and non-linear optical properties of ADD are studied together with the Ag/ADD/p-Si/Al hetero-junction photodiode characteristics. The synthetic ADD is examined by using both Fourier transform infrared spectroscopy and nuclear magnetic resonance techniques. Its structure is also investigated using both X-ray diffraction and scanning electron microscopy techniques. Based on the spectrophotometric measurements of ADD thin film, several linear-optical parameters are calculated from the absorption spectra. The single-oscillator model is used to explain the dispersion parameters of ADD thin films. Semi-empirical relations are used to calculate the non-linear optical parameters from the linear optical parameters. The good optical properties of ADD thin films qualify ADD to be used in optoelectronic applications. So, Ag/ADD/p-Si/Al heterojunction photodiode is fabricated and its electrical properties are studied. Moreover, the Ag/ADD/p-Si/Al photodiode parameters (sensitivity, resistivity and detectivity) show good response to different illumination intensities.
原文链接:- NSTL
- Elsevier
Hao, ShuyingWu, RuiqinFeng, JingjingYu, Huajian...
16页查看更多>>摘要：Carbon nanotubes (CNTs) are sensitive elements for the fabrication of nanomechanical mass sensors with greatly improved sensitivity. In this paper, the axial vibration behavior of single-walled CNTs based mass sensors was examined by nonlocal elasticity theory and Euler-Bernoulli beam theory. The vibration governing equation of the system was derived by the Hamiltonian principle, and the relationships of frequency equations and responses describing the vibration characteristics were all established. An approximate analytical method and simple expression for calculating the fundamental frequency were provided to obtain the expressions of natural frequencies with explicit physical parameters. In addition, combining with the theoretical analysis and considering the damping environment of the sensor under actual working conditions, LAMMPS molecular dynamics simulations were applied to compare and discuss the influence of various physical factors on the vibration behaviors of mass sensors. And the stable vibration signal generated by the damping was used to identify whether the attached nanoparticles fall off. The data revealed that the increase in tip attached mass and adjustment nonlocal parameters could effectively improve the sensitivity of mass sensors.
原文链接:- NSTL
- Elsevier
Shenouda, S. S.Shakra, A. M.Yahia, I. S.
7页查看更多>>摘要：Films of indigo dye as organic semiconductors have been prepared with different thicknesses (462-885 nm) through thermal evaporation. X-ray diffraction shows a nanocrystalline structure for the films with crystallite size 10.5 +/- 0.1 nm. AFM confirms the nanocrystalline structure of the prepared films. The optical properties of the indigo films have been investigated using Swanepoel's method. These films have 2 optical energy gaps (1.67 and 2.61 eV) and Urbach's energy of 0.22 eV. The refractive index has normal behavior to decrease with increasing the wavelength following the Cauchy formula and the single oscillator model. The oscillator energy Eo and dispersion energy Ed are 2.75 and 4.81 eV, respectively. The lattice dielectric constant epsilon L is 2.89 while the static dielectric constant epsilon s is 2.75. The linear/nonlinear optical susceptibility and nonlinear refractive index have similar behavior to increase with increasing the photon energy.
原文链接:- NSTL
- Elsevier
Zhang, WeiYang, XinhuiQu, ZhiweiLiu, Zirui...
6页查看更多>>摘要：Ga-doped ZnO (GZO) powders were synthesized by chemical coprecipitation. GZO powders were annealed in O-2, Ar, N-2, and H-2 atmosphere, and the effects of annealing atmosphere on their structure, optical and electrical properties were systematically studied. The results show that the optical and electrical properties of GZO powder were highly influenced by annealing atmosphere. GZO annealed in Ar, N-2, H-2 atmosphere have excellent electrical resistivity, while GZO annealed in O-2 atmosphere has poor electrical resistivity. According to the annealing contrasted of GZO in different atmosphere, the lower resistivity of GZO is, the lower reflectivity will be. The blue shift of ultraviolet emission (385 nm) in photoluminescence of GZO is related to oxygen vacancy (VO) and doped Ga, the blue and green emissions (around 500 nm) are originated from VO defects. The density of VO defects and the effective doping rate of Ga will be enhanced when GZO annealed in Ar, N-2, H-2 atmosphere.
原文链接:- NSTL
- Elsevier
Dhas, S. A. Martin BrittoSivakumar, A.Dhas, S. Sahaya JudeKumar, Raju Suresh...
7页查看更多>>摘要：In the present research article, we have performed an extensive experimental investigation on the structural and linear optical properties of the prismatic face ammonium dihydrogen phosphate (ADP) crystals under the impact of shock waves of various counts such that the crystals have been analyzed by X-ray diffraction, Raman spectroscopic, Ultra-violet Visible spectroscopic and optical microscopic techniques. XRD and Raman results clearly show that the shocked ADP crystals have undergone significant changes such as lattice deformations, lattice disorders giving rise to the structural disorders and significant reduction in optical transmittance with respect to the number of shock pulses. Optical microscopic images also authenticate the formation of defective surface morphology at shocked conditions. Furthermore, we have made the comparison of the optical transmission of the prismatic face with the previously published pyramidal face ADP crystal with respect to the number of shock pulses.
原文链接:- NSTL
- Elsevier
Jose, AdonKrishnapriya, T.Jose, Jeena RoseJoseph, Cyriac...
9页查看更多>>摘要：Spectroscopic investigation on the optical characteristics of 1.06 mu m (F-4(3/2) -> I-4(11/2)) transition of Nd3+ ions with different concentration in fluoroborosilicate (FBSND) glasses is reported. The glass transition temperature estimated via DSC analysis confirmed the thermal stability of the Nd3+ doped fluoroborosilicate glassy system. The phenomenological Judd-Ofelt parameters were evaluated by implementing the Judd-Ofelt (JO) theory on the recorded absorption spectrum and the parameters. Strong NIR emission has been observed for the lasing transition at 1.06 mu m under an excitation of 584 nm. The emission intensity of all the luminescent bands in the NIR emission spectra of FBSND glasses observed to be increased up to 1 mol% and after that a fall in emission intensity is observed due to concentration quenching. Large value of JO intensity parameters and radiative properties such as branching ratio, stimulated emission cross section, radiative transition probability recommends FBSND glasses for photonic applications.
原文链接:- NSTL
- Elsevier
Iida, TsutomuYamaguchi, MasatoHirayama, NaomiImai, Yoji...
9页查看更多>>摘要：Low-temperature thermoelectric materials are attracting increased attention for their use in cold power generators and as power supplies for self-powered wireless sensors. To improve their thermoelectric performance, it is necessary to investigate the effects of impurity dopants and crystal defects on their transport properties using experimental and theoretical approaches. However, for narrow-gap semiconducting materials, the bandgap is underestimated by conventional density functional theory calculations, which often results in incorrect predictions of carrier transport properties. The present study investigates the effects of native crystal defects in low temperature thermoelectric semiconducting alpha-SrSi2, which has an extremely small bandgap of 13-35 meV, using first-principles calculations and adopting the Gaussian-Perdew-Burke-Ernzerhof hybrid functional. Consequently, we are able to clarify the effects of two types of point defects (i.e., vacancies and antisite defects) on the energetic stability, electronic structure, and thermoelectric performance of alpha-SrSi2 and to discuss the origins of the experimental p-type conduction in pure alpha-SrSi2.
原文链接:- NSTL
- Elsevier
