[en] A recommended isotropic dipole oscillator strength distribution (DOSD) has been constructed for the silane (SiH₄) molecule through the use of quantum mechanical constraint techniques and experimental dipole oscillator strength data. The constraints are furnished by experimental molar refractivity data and the Thomas-Reiche-Kuhn sum rule. The DOSD is used to evaluate a variety of isotropic dipole oscillator strength sums, logarithmic dipole oscillator strength sums, and mean excitation energies for the molecule. A pseudo-DOSD for SiH₄ is also presented which is used to obtain reliable results for the isotropic dipole-dipole dispersion energy coefficients C₆, for the interaction of silane with itself and with forty-four other species, and the triple-dipole dispersion energy coefficient C₉ for (SiH₄)₃

[en] We study and constrain the parameter space of the color octet vector model from the observed m_tt-bar and δ_y distribution and spin correlation at Tevatron with the full data set through the flavor conserving and violating couplings. In order to ensure that we remain within the constraints imposed by the LHC data, we analyse the charge asymmetry and invariant mass and P_T spectrum in the tt-bar production data at the LHC. The constraints from the dijet resonance searches performed by LHC are also considered. We also explore the contribution of this model to the single top quark production mediated by charged and neutral color octet vector bosons. FV couplings introduced then induce the same sign top pair production process which is analyzed for both the hadron colliders. We have incorporated the effect of finite decay width of color octets on these processes. We find that it is possible to explain the observed A_FB^t anomaly in the color octet vector model without transgressing the production cross-sections of all these processes both through FC and FV couplings at Tevatron and LHC. Our favorable data points in the parameter space are consistent with the charge asymmetry and spin-correlation. (author)

[en] Kinetically controlled growth of gallium (Ga) metal has been reported on high index stepped Si (553) surface and its thermal stability with various novel superstructural phases has been analyzed. Auger electron spectroscopy studies revealed that the adsorption of Ga at room temperature (RT) follows Frank–van der Merwe (FM) growth mode while for higher substrate temperature, Ga adsorption remains within the submonolayer range. Thermal desorption and low energy electron diffraction studies investigated the formation of thermally stable Ga-islands and the various Ga induced superstructural phase on Si (553). During room temperature adsorption, (1 1 1)7 × 7 facet of Si (553) reconstructed into (1 1 1)6 × 6 facet while during desorption process, stable (1 1 1)6 × 6 and (1 1 1)√3 × √3-R30° surface reconstructions has been observed.

[en] LR-115 plastic track detectors have been used for the measurement of radon exhalation rate and radium concentration in soil samples collected from some villages of Kangra district, Himachal Pradesh, India. Uranium concentration has also been determined in these soil samples using fission track technique. Radium concentration in soil samples has been found to vary from 11.54 to 26.71 Bq Kg^-1, whereas uranium concentration varies from 0.75 to 2.06 ppm. The radon exhalation rate in these samples has been found to vary from 15.16 to 35.11 mBq Kg^-1 h^-1 (502.12 to 1162.64 mBq m^-2 h^-1)

[en] Distorted-wave calculations are reported for positron impact excitation of the helium atom. 1¹S-2¹S(2¹P) transitions are studied. Closed-form expressions for scattering amplitudes are obtained. Present results are compared with the earlier theoretical estimates. (author)

[en] Films of graphene oxide (GO) and amide functionalized graphene oxides (AGOs) were deposited on SiO_2/Si(100) by spin coating and were thermally annealed at different temperatures. Sheet resistance of GO and AGOs films was measured using four probe resistivity method. GO an insulator at room temperature, exhibits decrease in sheet resistance with increase in annealing temperature. However, AGOs' low sheet resistance (250.43 Ω) at room temperature further decreases to 39.26 Ω after annealing at 800 °C. It was observed that the sheet resistance of GO was more than AGOs up to 700 °C, but effect was reversed after annealing at higher temperature. At higher annealing temperatures the oxygen functionality reduces in GO and sheet resistance decreases. Sheet resistance was found to be annealing time dependent. Longer duration of annealing at a particular temperature results in decrease of sheet resistance. - Highlights: • Amide functionalized graphene oxides (AGOs) were synthesized at room temperature (RT). • AGO films have low sheet resistance at RT as compared to graphene oxide (GO). • Fast decrease in the sheet resistance of GO with annealing as compared to AGOs • AGOs were found to be highly dispersible in polar solvents

[en] Highlights: • Novel technique to synthesis self-assembled InN nanorings by low energy N. • Anisotropic strain relaxation driven self-assembly lead to formation of nanorings. • Strong downward band bending in VB-spectra signify large electron accumulation. - Abstract: A novel technique for synthesis of high crystalline quality self-assembled InN nanorings, by nitriding the bulk deposited In/Si (5 5 3)-1 × 4 system using low energy N_2"+ ions at 520 °C, has been demonstrated. Scanning electron microscopy images reveal the formation of ring shaped InN structures with average size ∼500 nm. Anisotropic strain relaxation via self assembly could be the driving force for the formation of these InN rings on reconstructed Si (5 5 3) surface. High resolution X-ray diffraction analysis indicates high crystalline quality of these wurtzite InN nanostructures with c-plane. A strong downward band bending was observed in X-ray photoelectron spectroscopy valence band spectra which signify the large electron accumulation in the InN nanostructures

[en] The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K have been determined by gamma-ray spectrometry. The measured activity in the selected building materials ranges from (3.2 to 151.7 Bq/kg), 14 to 63.7 Bq/kg and 24.3 to 121.5 Bq/kg for ²²⁶Ra, ²³²Th and ⁴⁰K respectively. The activity concentration of ²³⁸U has been determined using fission track technique and the value ranges from 0.11 to 3.85 ppm. The concentrations for these natural radionuclides are compared with the reported data from other countries. Radium-equivalent activities (Ra_eq) are calculated for the measured samples to assess the radiation hazards arising due to the use of these materials in the construction of dwellings. All building materials have shown Ra_eq activities lower than the limit set in the Organization for Economic Cooperation and Development (OECD) report (370 Bq/kg), equivalent to external gamma dose of 1.5 mSv yr^-1. A good correlation has been observed between ²³⁸U and ²²⁶Ra in these materials

[en] In recent years we have developed different techniques for plasma instrumentation. Within the paper we briefly review the developments of spectroscopic equipment's for their current aspects under the plasma spectroscopy using the general formulations of atomic spectroscopy. Special emphasis will be place on the development simple technique for plasma spectroscopy with several its multidimensional aspects in present scenario of plasma science and nuclear materials. (author)

[en] In Indus-2 we have a total of 56 button type beam position indicator. Of these 56 BPIs 40 are individual type and 16 are integrated with dipole magnet's vacuum chamber. All 56 BPIs are identical. Signal from these BPIs are measured using narrow band signal processing at 505.8 MHz. Since these BPIs were designed for narrow band signal processing, some variation of characteristics impedance from button to feed through has been accepted to accommodate ease of mechanical fabrication and fitting. It is proposed to upgrade these BPIs as a XIth plan project to -wide band structure. This paper presents simulation of button to feed through assembly of Indus-2 BPIs to understand the behavior at higher harmonics using Ansys. (author)