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91.
In this work, a bridge density functional approximation (BDFA) (J. Chem. Phys. 112, 8079 (2000)) for a nonuniform hard-sphere fluid is extended to a non-uniform hard-core repulsive Yukawa (HCRY) fluid. It is found that the choice of a bulk bridge functional approximation is crucial for both a uniform HCRY fluid and a non-uniform HCRY fluid. A new bridge functional approximation is proposed, which can accurately predict the radial distribution function of the bulk HCRY fluid. With the new bridge functional approximation and its associated bulk second order direct correlation function as input, the BDFA can be used to well calculate the density profile of the HCRY fluid subjected to the influence of varying external fields, and the theoretical predictions are in good agreement with the corresponding simulation data. The calculated results indicate that the present BDFA captures quantitatively the phenomena such as the coexistence of solid-like high density phase and low density gas phase, and the adsorption properties of the HCRY fluid, which qualitatively differ from those of the fluids combining both hard-core repulsion and an attractive tail. 相似文献
92.
New phase formation at the La0.9Sr0.1MnO3/YSZ interface and its effects on the cathodic performances were studied at 900 °C in air. The resistance caused by the interfacial product layer kept increasing with time to reach up to 40% of the total resistance after 500 h. The interfacial product was identified as La2Zr2O7 by XRD measurement. The electrical conductivity of La2Zr2O7 (2.4 × 10−5 S cm−1 at 1000 °C), measured by AC impedance and current interruption methods, was 4 to 7 orders of magnitude smaller than those of La0.9Sr0.1MnO3 electrode or YSZ electrolyte. Either the electronic conductivity or the electrochemical O2 reduction activity of La2Zr2O7 was negligible. Combining these results, a conclusion was made that the cathodic degradation comes mainly from the growth of interfacial product layer and its contribution to the cell resistance increment is ohmic in nature. 相似文献
93.
W. Goldacker M. Quilitz B. Obst H. Eckelmann 《Physica C: Superconductivity and its Applications》1998,310(1-4):182-186
Hysteresis losses and coupling losses, a main component of the AC losses in Bi(2223) tapes, can effectively be reduced by enhancing the resistivity of the matrix material between the filaments and applying a filament twist. Since through alloying the sheath, as using AgAu(8 wt.%), the resistivity can only be raised by a factor <10 (77 K), a new conductor configuration with a quite novel composite matrix having resistive SrCO3 barriers inside the Ag matrix between the filaments was developed. These new barriers, a cheap and commercial material, withstand the tape annealing, do not react with the superconductor, sinter dense and have a good bonding to Ag. Applying two different preparation techniques for 19 filament prototype tapes, critical current densities up to 20.7 kA cm−2 were achieved. We report on tape preparation, the effect on the phase texture and the superconducting properties of such barrier tapes. 相似文献
94.
D. E. Daney M. P. Maley H. J. Boenig J. O. Willis J. Y. Coulter L. Gherardi G. Coletta 《Physica C: Superconductivity and its Applications》1998,310(1-4):236-239
We report single-phase AC loss measurements on 8-, 4-, and 3-layer, multi-strand, HTS prototype conductors for power transmission lines. We use both calorimetric and electrical techniques. The agreement between the two techniques suggests that the interlayer current distribution in 1-m long conductors are representative of those in long conductors. The losses for the 8- and 4-layer conductors are in rough agreement, with the 8-layer losses being somewhat lower. The 3-layer conductor losses are substantially higher — probably due to unbalanced azimuthal currents for this configuration. 相似文献
95.
P.?G.?ChufyrevEmail author N.?V.?Sidorov N.?N.?Mel'nik 《Journal of Applied Spectroscopy》2005,72(5):667-670
Using the Raman scattering spectra, we investigated the ordering of the structural units in the cation sublattice and the
photorefractive properties of lithium niobate single crystals of variable composition, i.e., nominally pure ones with different
Li/Nb ratios and those doped with the nonphotorefractive cations Mg2+, Gd3+, and Y3+. It is shown that at low concentrations of Mg2+, Gd3+, and Y3+ the magnitude of the photorefractive effect is substantially determined by the ordering of the structural units of the cation
sublattice. It has been found for the first time that the intensity of the line corresponding to the bridge valence vibrations
of oxygen atoms in the octahedrons of NbO6 is sensitive to the dipole ordering of the cation sublattice of the crystal.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 5, pp. 611–614, September–October, 2005. 相似文献
96.
Applying the time-dependent density functional theory (TD-DFT) method the design of molecular logical functions from the dithieno[3,2-b:2,3-d]thiophene (thiophene) and azo-dye Disperse Orange 3 (DO3) molecules joined with various electron-insulator bridges is performed. Based on the results of the investigations, the main design rules for the selection of the bridge fragment between a photo-acceptor and photo-donor of a charge transfer molecular device are proposed. 相似文献
97.
Simon A. King 《Transactions of the American Mathematical Society》2004,356(11):4519-4542
We introduce a numerical isomorphism invariant for any triangulation of . Although its definition is purely topological (inspired by the bridge number of knots), reflects the geometric properties of . Specifically, if is polytopal or shellable, then is ``small' in the sense that we obtain a linear upper bound for in the number of tetrahedra of . Conversely, if is ``small', then is ``almost' polytopal, since we show how to transform into a polytopal triangulation by local subdivisions. The minimal number of local subdivisions needed to transform into a polytopal triangulation is at least . Using our previous results [The size of triangulations supporting a given link, Geometry & Topology 5 (2001), 369-398], we obtain a general upper bound for exponential in . We prove here by explicit constructions that there is no general subexponential upper bound for in . Thus, we obtain triangulations that are ``very far' from being polytopal. Our results yield a recognition algorithm for that is conceptually simpler, although somewhat slower, than the famous Rubinstein-Thompson algorithm.
98.
Existence results for some fourth-order nonlinear elliptic problems of local superlinearity and sublinearity 总被引:1,自引:0,他引:1
Guixiang Xu 《Journal of Mathematical Analysis and Applications》2003,281(2):633-640
In this paper we study the existence of positive solutions for the problem
(0.1) 相似文献
99.
The ac conductivity and dielectric properties of spinel ferrite nanoparticles of Li0.1(Ni1−xZnx)0.8Fe2.1O4 (x=0.0–1.0) prepared by the chemical co-precipitation method were investigated as functions of frequency and temperature by using a complex impedance technique. Parts of the precipitated powders were pressed into a disk-shape and were sintered at 1473 K for 2 h to increase the particle size to the bulk scale (dimensions >100 nm). The ac conductivity of the samples increases with increasing temperature, ensuring the semiconducting behavior of both nano and bulk samples, in agreement with the Koops model to describe heterogeneous structures. The significant decrease in ac conductivity σ′ac, dielectric constant, and dielectric loss of the as-prepared nanosamples compared to their bulk counterparts is correlated to the small size of the grain compared to the grain boundary size. This might be useful for many applications requiring the reduction of eddy current effects. 相似文献
100.
The response of a spinless ballistic Luttinger liquid ring to an oscillating in time magnetic flux is considered in the discrete spectrum limit. The dependence of the magnitude of both AC response and the DC current on the frequency and magnitude of a magnetic flux at nonzero temperatures is calculated. 相似文献