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Vitoria P Muga I Gutiérrez-Zorrilla JM Luque A Román P Lezama L Zúniga FJ Beitia JI 《Inorganic chemistry》2003,42(4):960-969
Several cyanogold complexes react with the binuclear nickel complex [(Ni(dien)(H(2)O))(2)(mu-ox)](PF(6))(2).2H(2)O to give the compounds [(Ni(dien)(H(2)O))(2)(mu-ox)]Br(2) (1), [(Ni(dien)(Au(CN)(2)))(2)(mu-ox)] (2), and [(Ni(dien))(2)(mu-ox)(mu-Au(CN)(4))](PF(6)) (3) (dien, diethilenetriamine; ox, oxalate). In the case of compounds 2 and 3, water displacement by the corresponding cyanogold complex takes place, whereas compound 1 is formed by a substitution of the anion. The crystal structures of compounds 1 and 2 present a 2D arrangement where the layers are connected by van der Waals forces (1) or N-H.Ntbd1;C hydrogen bonds (2), where each binuclear complex is hydrogen bonded to its neighbors, whereas compound 3 presents a novel structure where the tetracyanoaurate acts as a bridging ligand to give a polymeric compound. Magnetic studies of these compounds reveal an antiferromagnetic behavior. Finally, density functional theory (DFT) calculations have been performed on isolated models of compounds 2 and 3 in order to gain some insight about the different behavior of the [Au(CN)(2)](-) and [Au(CN)(4)](-) groups as ligands and proton acceptors in hydrogen bonds. 相似文献
23.
A series of novel monoazo disperse dyes based on 2-amino-5-nitro-4-(p-nitrophenyl)thiazole were prepared using various N,N-dialkylaniline derivatives as the coupling components. The spectral properties in the IR and visible range of the dyes were investigated. The dyeing performance of these dyes was assessed on nylon fabric. These dyes were found to give a wide range of color shades from reddish brown to indigo with excellent brightness, levelness, and depth on nylon fabric. The dyed fabric showed fairly good light fastness, good to excellent fastness to wash and perspiration, and excellent fastness to sublimation. The dyebath exhaustion and fixation of the dyes on nylon were found to be very good and acceptable. 相似文献
24.
We demonstrate that it is possible to discern the way that has been followed to measure a quantum observable that can be expressed in terms of different products of observables, whereas no such discrimination is possible by assigning predetermined values. Specifically we show how to distinguish different routes (contexts) to measure C=AB=A′B′, when C,A,B and C,A′,B′ commute with each other, but A and B do not commute with A′ and B′. 相似文献
25.
J. R. Reddy G. Ravi Naveen Kumar Veldurthi Radha Velchuri Someshwar Pola Muga Vithal B. Sreedhar 《无机化学与普通化学杂志》2013,639(5):794-798
KSbWO6 was prepared by sol‐gel method. N‐doped KSbWO6 (KSbWO6–xNx) was obtained by heating KSbWO6 and urea at 400 °C. Both the compounds are characterized by powder X‐ray diffraction (XRD), TEM, SEM‐EDS, X‐ray photo electronic spectroscopy (XPS), and UV/Vis diffuse reflectance spectroscopy (UV‐DRS). A shift in the peak positions of powder XRD and XPS spectra was observed. The band gap energy (Eg) of KSbWO6 and N‐doped KSbWO6 was obtained from their diffused reflectance spectra.Eg was reduced from 3.17 eV to 2.56 eV upon nitrogen doping in KSbWO6. The reduction of the Eg is attributed to the lifting of valence band of N‐doped KSbWO6, due to the mixing of O 2p states with N 2p states. The photocatalytic activity of both the samples was studied by degradation of methylene blue (MB). The nitrogen doped KSbWO6 shows higher photocatalytic activity compared to that of KSbWO6. 相似文献
26.
David Pardo Pawel Matuszyk Ignacio Muga Carlos Torres-Verdín Angel Mora Victor M. Calo 《Journal of computational physics》2011,230(16):6320-6333
The paper introduces a high-order, adaptive finite-element method for simulation of sonic measurements acquired with borehole-eccentered logging instruments. The resulting frequency-domain based algorithm combines a Fourier series expansion in one spatial dimension with a two-dimensional high-order adaptive finite-element method (FEM), and incorporates a perfectly matched layer (PML) for truncation of the computational domain. The simulation method was verified for various model problems, including a comparison to a semi-analytical solution developed specifically for this purpose. Numerical results indicate that for a wireline sonic tool operating in a fast formation, the main propagation modes are insensitive to the distance from the center of the tool to the center of the borehole (eccentricity distance). However, new flexural modes arise with an increase in eccentricity distance. In soft formations, we identify a new dipole tool mode which arises as a result of tool eccentricity. 相似文献
27.
J. R. Reddy G. Ravi P. Suresh Naveen Kumar Veldurthi Radha Velchuri M. Vithal 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1321-1327
Single source precursor, antimony potassium tartrate, was used for the preparation of Sb2O3, KSb3O5, K0.51Sb 0.67 III Sb 2 V O6.26, and KSbO3. Antimony trioxide (Sb2O3) was prepared by hydrothermal method, while potassium antimony oxides (KSbO3, K0.51Sb 0.67 III Sb 2 V O6.26, and KSbO3) were obtained from the thermal decomposition of antimony potassium tartrate. All the compounds were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), UV–Vis diffuse reflectance spectra, and scanning electron microscopy (SEM). The decomposition process of antimony potassium tartrate with temperature was given. The product formation at different temperatures of thermal decomposition was monitored by PXRD and FT-IR. The TG profile of antimony potassium tartrate shows mass loss at three regions. The infrared spectra of parent and decomposed products gave characteristic Sb-O bands. The band gap energy of decomposed products was obtained. The SEM diagrams of Sb2O3 show different morphologies. Direct solid state preparation of KSb3O5 and K0.51Sb 0.67 III Sb 2 V O6.26 under identical experimental conditions was unsuccessful. 相似文献
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29.
This Note gives answers to the uniqueness and existence questions for solutions of the Helmholtz equation in an half-plane with an impedance or mixed boundary condition. We deal with unbounded domains which boundaries are unbounded too. The radiation conditions are different from the ones that we found in an usual exterior problem due to the appearance of surface waves. We first compute and study the half-plane Green's function to see how the solutions behave at infinity, and second obtain integral representation for these solutions. To cite this article: M. Duran et al., C. R. Acad. Sci. Paris, Ser. I 340 (2005). 相似文献
30.
Koteswara Rao K Anantharamulu N Salagram M Vithal M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(3):646-649
Bulk and nano sized pyrochlore of composition La(2-x)Gd(x)Zr(2)O(7) (x=0.025, 0.05, 0.075 and 0.1) have been prepared by sol-gel method. They are characterized by powder X-ray diffraction and infrared spectroscopy. The sintering temperature influences the particle size of the sample. The room temperature powder ESR of La(1.95)Gd(0.05)Zr(2)O(7) gave characteristic "U" spectrum. The influence of particle size on the ESR of Gd(3+) is investigated. Possible reason for the disappearance of "U" spectrum with increase in the particle size is given. 相似文献