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61.
We propose a new approximation scheme to obtain analytic expressions for the bond-state energies and eigenfunctions for any arbitrary bound nl-state of the Hulthén potential. The predicted energies Enl are in excellent agreement with the perturbative results of Lai and Lin. The scope for an extension of the method to the continuum states is also discussed. 相似文献
62.
The ruthenium(II) complex [RuI2(Me2SO)4] was synthesized and characterized. The Me2SO ligands are all S-bonded. Reactions of RuI2(Me2SO)4 with ligands containing P, N and S donor atoms have been carried out and the complexes obtained were characterized using different physical methods. [RuI2L4] (L= CH3CN, Me2SO and py), [RuI2(CH3CN)2(PPh3)2] and [RuI2(CS)(PPh3)3] have been synthesized using RuI3 as the source material and characterized as above. 相似文献
63.
Gregory A. Dilisi Charles Rosenblatt Robert B. Akins Anselm C. Griffin Uma Hari 《Liquid crystals》1992,11(1):63-71
The dialkoxyphenylbenzoate monomer '5005' (C5H11OC6H4COOC6H4OC5H11) and its dimer were aligned parallel to a buffed polyimide-coated glass substrate. A magnetically induced Freedericksz transition in both thick and thin cells was used in conjunction with a capacitance technique to determine the anchoring strength coefficient Was a function of temperature in the nematic phase. It was found that for both monomer and dimer, Wincreases with decreasing temperature. The anchoring coefficient for the dimer, however, was found to be an order of magnitude larger than for the monomer at comparable reduced temperatures. The splay elastic moduli were also determined for both species, and found to be of comparable magnitude, consistent with previous results. 相似文献
64.
The cell model for diffusion transition has been applied to study first order phase transition and its pressure dependence in polyethylene. The experimental data of Matsuoka have been utilized. The agreement with experimental curves gets progressively better at higher pressure values because of the accompanied crystallisation. 相似文献
65.
Uma Basu Indira Addy Bidyut Kumar Datta 《International Journal of Theoretical Physics》1980,19(9):681-691
Recently Addy and Datta have obtained a linearized solution for isentropic motions of a perfect fluid by assigning Cauchy data on the hypersurfacex
4=0 and by imposing a restriction on the equation of state. In the present paper we pursue this study and discuss the problem of singularities from the standpoint of a local observer for which a singularity is defined as a state with an infinite proper rest mass density. It is shown that for a closed universe with any distribution of matter whatsoever there occurred a singularity in the past in the nonrotating parts of the universe and it must recur in the future. Furthermore, the collapse of a rotating fluid to a singularity seems inevitable when the relativistic equation of state is considered. 相似文献
66.
We study the connections between one-sided Hopf algebras and one-sided quantum quasigroups, tracking the four possible invertibility conditions for the left and right composite morphisms that combine comultiplications and multiplications in these structures. The genuinely one-sided structures exhibit precisely two of the invertibilities, while it emerges that imposing one more condition often entails the validity of all four. A main result shows that under appropriate conditions, just one of the invertibility conditions is su?cient for the existence of a one-sided antipode. In the left Hopf algebra which is a variant of the quantum special linear group of two-dimensional matrices, it is shown explicitly that the right composite is not injective, and the left composite is not surjective. 相似文献
67.
Nanocrystalline zinc oxide (ZnO) thin films have been deposited by spin-coating polymeric precursors synthesized by the citrate precursor route using ethylene glycol and citric acid as chelating agents. The ZnO thin films were annealed in air at different temperatures for 10 min. The films were characterized by different structural and optical techniques, including X-ray diffraction (XRD), atomic force microscopy (AFM), optical transmission spectroscopy, and photoluminescence (PL). The thermal decomposition of polymeric precursor was studied by thermogravimetric analysis (TGA). XRD analysis with grazing incidence and rocking curves indicate that the ZnO films are polycrystalline with preferential orientation along the c-axis direction with a full-width at half-maximum (FWHM) of 0.31° for 600 °C-annealed samples. On annealing, the texturing in films increased along with a decrease in FWHM. AFM micrographs illustrate that the ZnO films are crack-free with well-dispersed homogeneous and uniformly distributed spherical morphology. The synthesized ZnO thin films have transparency >85% in the visible region exhibiting band edge at 375 nm, which becomes sharper with anneal. Room temperature PL spectra of these films show strong ultraviolet (UV) emission around 392 nm with an increase in intensity with annealing temperature, attributed to grain growth. Deconvolution of the PL spectra reveals that there is coupling of free excitons with higher orders of longitudinal optical (LO) phonon replicas leading to a broad asymmetric near-band-edge peak. 相似文献
68.
A novel thionation protocol for carbonyl compounds, with the system PSCl3/H2O/Et3N has been discovered. Clean, rapid, and efficient synthesis of a variety of thiocarbonyl compounds such as thioamides, thiolactams, thioketones, thioxanthones, and thioacridone can be achieved through this simple and convenient method under solventless condition with microwave irradiation. 相似文献
69.
Phosphosilicate doped with a mixture of phosphotungstic acid and zirconium oxide (PWA/ZrO2–P2O2–SiO2) was investigated as potential glass composite membranes for use as H2/O2 fuel cell electrolytes. The glass membranes were studied with respect to their structural and thermal properties, proton conductivity, pore characteristics, hydrogen permeability, and performance in fuel cell tests. Thermal analysis including TG and DTA confirmed that the glass was thermally stable up to 400 °C. The dependence of the conductivity on the humidity was discussed based on the PWA content in the glass composite membranes. The proton transfer in the nanopores of the PWA/ZrO2–P2O5–SiO2 glasses was investigated and it was found that a glass with a pore size of ∼3 nm diameters was more appropriate for fast proton conduction. The hydrogen permeability rate was calculated at various temperatures, and was found to be comparatively higher than for membranes based on Nafion®. The performance of a membrane electrolyte assembly (MEA) was influenced by its PWA content; a power density of 43 mW/cm2 was obtained at 27 °C and 30% relative humidity for a PWA/ZrO2–P2O5–SiO2 glass membrane with a composition of 6–2–5–87 mol% and 0.2 mg/cm2 of Pt/C loaded on the electrode. 相似文献
70.
Three series of novel dimeric supramolecules, possessing both inter- as well as intramolecular H-bonding, have been prepared and investigated for their thermal properties. They were obtained in excellent yields by condensing cholesteryl ω-(3-hydroxy-4-formylphen-oxy)alkanoates with 4-(n-alkoxy)benzohydrazides, 3,4-bis(n-decyl-oxy)benzohydrazide and 3,4,5-tris(n-decyloxy)benzohydrazide. The influence of increase in the number of terminal n-alkoxy tails from one to three and the length and parity of the flexible spacer on phase transitional behaviour have been thoroughly investigated with the aid of microscopic, calorimetric and X-ray diffraction (XRD) techniques. The results of these complementary studies clearly illustrate the dependence of thermal behaviour of the dimers on these structural factors. The rigid intermolecular association via H-bonds through complementary benzohydrazide component enforce their self-assembly into frustrated and polar smectic phases; H-bond force coupled with the bulkiness of steroid moiety affects the electrical switching property of this fluid polar structure. 相似文献