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961.
We present a streamline diffusion shock capturing spacetime discontinuous Galerkin (DG) method to approximate nonlinear systems of conservation laws in several space dimensions. The degrees of freedom are in terms of the entropy variables and the numerical flux functions are the entropy stable finite volume fluxes. We show entropy stability of the (formally) arbitrarily high order accurate method for a general system of conservation laws. Furthermore, we prove that the approximate solutions converge to the entropy measure valued solutions for nonlinear systems of conservation laws. Convergence to entropy solutions for scalar conservation laws and for linear symmetrizable systems is also shown. Numerical experiments are presented to illustrate the robustness of the proposed schemes. 相似文献
962.
Raman spectroscopic measurements were carried out in the temperature range 10–300 K to understand the low‐temperature antiferroelectric (AFE)–ferroelectric (FE) phase transition in NaNbO3. Several modes in the low wavenumber range were found to disappear, while some new modes appeared across the transition. The temperature dependence of mode wavenumbers suggests that, during cooling, the AFE–FE phase transition begins to occur at 180 K, while the reverse transition starts at 260 K during heating. During cooling, the two phases were found to coexist in the temperature range of 220–160 K. Upon heating, the FE phase is retained up to 240 K and both FE and AFE phases coexist in the temperature range 240–300 K. In contrast to the earlier reports, the present results suggest a different coexistence region and the reverse transition temperature. The reported relaxor‐type FE behaviour over a broad temperature is consistent with the observed coexistence of phases during cooling and heating cycles. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
963.
A. K. Mishra S. B. Mishra N. K. Kaushik 《Russian Journal of Coordination Chemistry》2009,35(4):296-301
Nickel(II) complexes of type [Ni(L)2Cl2] and [Ni(L)2(OCOCH3)2], where L = (cyclohexyl-N-thio)-1,2-ethylenediamine (L1) and (cyclohexyl-N-thio)-1,3-propanediamine (L2) has been synthesized and characterized by elemental analysis, FT-IR, mass, UV-Vis, and 1H NMR spectroscopic studies. The thiodiamines coordinate as a bidentate N-S ligand. The ratio of the metal: ligand was 1:
2 for all the complexes. The binding sites are the azomethine nitrogen and thioamide sulfur. The complexes are found to be
soluble in acetone, dimethylformamide, and dimethylsulfoxide. All the complexes were found amorphous in nature. Molar conductance
values in DMSO indicate the nonelectrolyte nature of the complexes. In vitro antifungal and in vitro antibacterial studies
were performed against fungal and bacterial strains, Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger, and Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, respectively. Preliminary antimicrobial screening shows the good results against both the fungal and the bacterial strains,
which can lead through the investigation of better drug.
The article is published in the original. 相似文献
964.
Ujjwal Koley Siddhartha Mishra Nils Henrik Risebro Magnus Svärd 《BIT Numerical Mathematics》2009,49(2):375-395
We describe high order accurate and stable finite difference schemes for the initial-boundary value problem associated with
the magnetic induction equations. These equations model the evolution of a magnetic field due to a given velocity field. The
finite difference schemes are based on Summation by Parts (SBP) operators for spatial derivatives and a Simultaneous Approximation
Term (SAT) technique for imposing boundary conditions. We present various numerical experiments that demonstrate both the
stability as well as high order of accuracy of the schemes.
相似文献
965.
The nanometric mixed tin-titanium oxide doped with a M(5+) cation was recently shown as a promising thermoelectric material. We report here synthesis of novel molecular precursors for above material using a convenient approach of reacting a metal chloride with a metal alkoxide. Heterometallic complexes with simple addition formula [(EtOH)(2)(OEt)(2)Ti(μ-OEt)(2)SnCl(4)] (1·EtOH) and [(EtOH)(OEt)(3)Ta(μ-OEt)(2)SnCl(4)] (2) were isolated in quantitative yield, which on recrystallization from isopropanol afforded mixed-alkoxide complexes [(Pr(i)OH)(2)(OPr(i))(2)Ti(μ-OEt)(2)SnCl(4)] (3) and [(Pr(i)OH)(OPr(i))(3)Ta(μ-OEt)(2)SnCl(4)] (4), respectively, thus indicating the robustness of the heterometallic M(μ-OEt)(2)Sn core in the solution phase. Facile conversion of these precursors to halide-free spinodal form of Ta(5+)-doped TiO(2)-SnO(2) as a potential thermoelectric material is reported. 相似文献
966.
A new coumarin based hydrazone (receptor 1) synthesized by modifying one of our earlier reported receptor detected fluoride ion selectively through naked eye in aq. DMSO (5:95, v/v). It was also able to detect fluoride through naked eye in a toothpaste sample. The addition of 1 equiv. of fluoride as its tetrabutylammonium salt to the 5 × 10−5 M aq. DMSO solution of the receptor 1 produced red color while the similar addition of acetate produced faint pink color. The dihydrogenphosphate and a variety of other anions were not able to produce any significant color change with receptor 1 under similar experimental conditions. The corresponding UV-vis measurements showed a bathochromic shifting of 455 nm band of receptor 1 to 514 and 484 nm for fluoride and acetate, respectively. The non-linear fittings of corresponding UV-vis titration data in 1:1 binding equation yielded association constants in 105:1 ratio for fluoride and acetate, respectively. The 1H NMR titrations studies shade further light on their mode of binding with receptor 1. The quantum mechanical calculations through time dependant density functional theory (TD-DFT) using basis set b3lyp/6-311g** supported our experimental findings nicely. 相似文献
967.
Mahato P Ghosh A Mishra SK Shrivastav A Mishra S Das A 《Chemical communications (Cambridge, England)》2010,46(48):9134-9136
Selective colorimetric detection of ATP in physiological conditions by a Zn(II)-based receptor is reported. This reagent was found to be non-toxic to the living cells and could be used for studying the growth of the yeast cells. 相似文献
968.
In this article, a convergence theorem and several comparison theorems are presented for a subclass of proper splittings of matrices introduced recently. 相似文献
969.
This paper reports the paramagnetic behavior of Mn doped ZnO co-doped with rare earth (Gd and Sm) atoms. The formation of secondary rare earth oxides (Gd2O3 and Sm2O3) is confirmed from the X-ray diffraction patterns. The rare earth oxides in the system forbids the grain growth and interconnection between the grains. The weak link between the grains suppresses the long range exchange interaction between the Mn ions and hence, reduces the ferromagnetic ordering. Owing to the large mismatch between ionic radii of rare earth and transition metal atoms inside the matrix, the rare earth element cannot contribute to promote ferromagnetic behavior in Mn doped ZnO, irrespective of their high individual magnetic moments. 相似文献
970.
Evidence of the Fano resonance in a temperature dependent Raman study of CaCu3Ti4O12 and SrCu3Ti4O12
Phononic excitations have been investigated using Raman scattering studies on CaCu(3)Ti(4)O(12) and SrCu(3)Ti(4)O(12) compounds as a function of temperature down to 10 K. Evidence of the Fano resonance effect is found in the A(g)(1) mode with an asymmetric phonon line shape that occurs because of composite electron-phonon scattering due to the onset of metallic fractions in the system. The evolution of the Fano line shape with temperature affirms the existence of nanoscale phase separation and the prominence of orbitally disrupted metallic regions above 100 K. Anomalies in the evolution of the line width of the A(g)(1) Raman mode with temperature are observed around 100 K where these compounds show an orbital order/disorder transition. These anomalies manifest mutual coupling of orbital degrees of freedom to lattice degrees of freedom. 相似文献