不同温度下氨基酸在α-咖啡碱水溶液中的体积、粘度及折光率特性

Measurements of density(ρ), viscosity(η), and refractive index(n), were carried out on α-amino acids, DL-solution at 298.15, 303.15, 308.15, and 313.15 K. These measurements have been carried out to evaluate some important parameters, viz., apparent molar volume (φv), partial molar volume (φv0), transfer volume (φ0v (tr)), viscosity A and B coefficients of Jones-Dole equation, free energies of activation per mole of solvent (△μ0#1) and solute (△μ0#2),enthalpies (△H*) and entropies (△S*) of activation of viscous flow, variation of B with temperature ((a)B/(a)T)P, and molar refractive index (RD). These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.     

Comparative study on BIS thiourea cadmium acetate crystals using HRXRD, etching, microhardness, UV-visible and dielectric characterizations

〈1 1 1〉 oriented bis thiourea cadmium acetate (BTCA) crystal of diameter 15 mm and length 45 mm was grown for the first time by the unidirectional Sankaranarayanan-Ramasamy (SR) method. The conventional and SR method grown BTCA crystals were characterized by using high-resolution X-ray diffraction (HRXRD), chemical etching, Vickers microhardness, UV-vis, dielectric studies and differential scanning calorimetry. The HRXRD analysis indicates that the crystalline perfection of SR method grown crystal is good without having any low angle internal structural grain boundaries. The transmittance of SR method grown BTCA is 14% higher than that of conventional grown crystal. The dielectric constant was higher and the dielectric loss was less in SR method grown crystal. The crystals grown by SR method possess less dislocation density and higher microhardness.     

Prospects of inflation with perturbed throat geometry

We study brane inflation in a warped deformed conifold background that includes general possible corrections to the throat geometry sourced by coupling to the bulk of a compact Calabi–Yau space. We focus specifically, on the perturbation by chiral operator of dimension 3/2 in the CFT. We find that the effective potential in this case can give rise to required number of e-foldings and the spectral index nS$n_S$ consistent with observation. The tensor to scalar ratio of perturbations is generally very low in this scenario. The COBE normalization, however, poses certain difficulties which can be circumvented provided model parameters are properly fine tuned. We find the numerical values of parameters which can give rise to enough inflation, observationally consistent values of density perturbations, scalar to tensor ratio of perturbations and the spectral index nS$n_S$.     

Neutron emission from 14N + 165Ho collisions at 35 MeV/u

Neutron emission from ¹⁴N + ¹⁶⁵Ho collisions has been studied at 25 MeV/u incident energy. Energy and angular distributions of the neutrons were measured in coincidence with projectile-like fragments (Li, Be, B, and C) emitted at angles of 10° and 30°. The spectra of neutrons at angles far from the angle of a coincident fragment have been satisfactorily parameterized in terms of a slowly moving, target-like source of temperature 2–3 MeV and a half-beam-velocity source of temperature about 7 MeV. The latter source accounts for about 20% of the detected neutrons for in-plane measurements. The out-of-plane cross sections are smaller. The relevant parameters of the moving-sources parametrization suggest a simple model which qualitatively explains the data in terms of the development of a hot participant zone and its subsequent mass exchange interactions with spectators in the projectile and target nuclei.     

Comparative study of optical parameters of fullerene C60 film at different temperatures

Fullerene C₆₀ thin films on glass substrate (around 2000 ? thickness) were prepared by thermal evaporation technique. The structural, surface morphology and optical properties of the films were studied. The optical properties of fullerene C₆₀ were investigated in the spectral range 200 nm to 900 nm using a UV-Vis spectrophotometer at room temperature as well as at liquid nitrogen temperature (77 K). The optical band gap at room temperature is found to be 2.30 eV, which gradually decreases with lowering the temperature and reaches to 2.27 at 77 K. The thickness and refractive index of fullerene C₆₀ film were calculated by ellipsometry. From the X-ray analysis, we have calculated the grain size, dislocation density, number of crystallite per unit area, and strain of the film at room temperature. The surface morphology of film was analyzed by scanning electron microscope (SEM). The present result show that the fullerene C₆₀ film becomes more conducting at low temperature.     

Double Series Identity and Some Laurent Type Hypergeometric Generating Relations

The main aim of this article is to obtain certain Laurent type hypergeometric generating relations. Using a general double series identity, Laurent type generating functions(in terms of Kampéde Fériet double hypergeometric function) are derived. Some known results obtained by the method of Lie groups and Lie algebras, are also modified here as special cases.     

Intermolecular Interactions in Binary Liquid Mixtures of Styrene with m-, o-, or p-xylene

The densities (ρ), ultrasonic speeds (ν), and refractive indices (n) of binary mixtures of styrene (STY) with m-, o-, or p-xylene, including those of their pure liquids, were measured over the entire composition range at the temperatures 298.15, 303.15, 308.15, and 313.15 K. The excess volumes (V^E), deviations in isentropic compressibilities (Δks), acoustic impedances (ΔZ), and refractive indices (Δn) were calculated from the experimental data. Partial molar volumes (V⁰_?,2) and partial molar isentropic compressibilities (K⁰_?,2) of xylenes in styrene have also been calculated. The derived functions, namely, V^E, Δk_s, ΔZ, Δn, V⁰_?,2, and K⁰_?,2 were used to have a better understanding of the intermolecular interactions occurring between the component molecules of the present liquid mixtures. The variations of these parameters suggest that the interactions between styrene and o-, m-, or p-xylene molecules follow the sequences: p-xylene>o-xylene>m-xylene. Apart from using density data for the calculation of VE, excess molar volumes were also estimated using refractive index data. Furthermore, several refractive index mixing rules have been used to estimate the refractive indices of the studied liquid mixtures theoretically. Overall, the computed and measured data were interpreted in terms of interactions between the mixing components.     

Do observations favour Galileon over quintessence?

We study the Galileon scalar field model arising as a decoupling limit of the Dvali–Gababdaze–Porrati (DGP) construction for the late time acceleration of the universe. The model has one extra Galileon correction term over and above the standard kinetic and potential energy terms for a canonical quintessence field. We aim to study whether the current observational data can distinguish between the Galileon and the quintessence field. Our study shows the remarkable result that for linear and ?²${?}^2$ potentials, the data prefers the Galileon model over quintessence with significant Bayesian evidence. It confirms that the observable universe indeed prefers the inclusion of higher derivative Galileon correction in the standard scalar field Lagrangian.     

Intercalation of KCl into layered neptunyl and plutonyl iodates

The hydrothermal reaction of Np(IV) or Pu(IV) with KIO₄ and CsCl at 180°C for 1 day results in the formation of NpO₂(IO₃)₂·0.5KCl·3.25H₂O (1) or PuO₂(IO₃)₂·0.5KCl·2.5H₂O (2). The neutral layers in compounds 1 and 2 are isostructural with NpO₂(IO₃)₂·H₂O and PuO₂(IO₃)₂·H₂O, respectively. The Np and Pu centers are found in distorted pentagonal bipyramidal [AnO₇] environments that are formed from the ligation of NpO₂²⁺ or PuO₂²⁺ cations by iodate anions. There are two crystallographically unique pyramidal iodate anions in 1 and 2. One of these anions utilizes all three oxygen atoms to simultaneously bridge three neptunyl or plutonyl units. The second anion only bridges two actinyl units and has a terminal oxo atom. The bridging of the actinyl cations by iodate anions creates neutral _∞²[AnO₂(IO₃)₃] (An=Np, Pu) sheets that are separated by K⁺ cations, Cl⁻ anions, and water molecules. Crystallographic data (203 K, MoKα, λ=0.71073): 1, monoclinic, space group C2/c,a=21.537(5) Å, b=11.670(3) Å, c=7.315(2) Å, β=93.033(4)°, Z=4, R(F)=5.43% for 136 parameters with 1309 reflections with I>2σ(I); 2, monoclinic, space group C2/c, a=21.570(4) Å, b=11.656(2) Å, c=7.348(2) Å, β=94.00(3), Z=4, R(F)=4.92% for 148 parameters with 1317 reflections with I>2σ(I).     

Laser wavelength effect on structural and optical properties of Cd34Se66 nanocrystalline thin film

Cadmium Selenide (Cd₃₄Se₆₆) thin films are deposited on a glass substrate using the thermal evaporation method at room temperature. The Cd₃₄Se₆₆ films are characterized using XRD. The crystallite size of the film is calculated from XRD data, which is found as 29.61 nm as-deposited. It is also found that crystallite size of Cd₃₄Se₆₆ changed after irradiation with N₂ and Nd:YAG laser. The changes in the optical properties of the films after irradiation with N₂ laser and Nd:YAG laser are also studied in the wavelength range of 300-700 nm and it is found that the optical band gap of the Cd₃₄Se₆₆ films changed after laser irradiation.