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91.
92.
Bobroff J Alloul H Ouazi S Mendels P Mahajan A Blanchard N Collin G Guillen V Marucco JF 《Physical review letters》2002,89(15):157002
We use 89Y NMR in YBa(2)Cu(3)O(6+y) in order to evaluate with high sensitivity the distribution of hole content p in the CuO2 planes. For y=1 and y=0.6, this hole doping distribution is found narrow with a full width at half maximum smaller than Deltap=0.025. This rules out any large static phase separation between underdoped and optimally doped regions in contrast with the one observed by STM in Bi2212 and by NQR in LaSrCuO. This establishes that static electronic phase separation is not a generic feature of the cuprates. 相似文献
93.
G. S. S. Saini Amit Sharma Sukhwinder Singh J. M. Abbas S. K. Tripathi Sarvpreet Kaur C. G. Mahajan H. H. Thanga A. L. Verma 《Journal of Raman spectroscopy : JRS》2007,38(12):1561-1569
We report a resonance Raman study on free‐base tetraphenylporphine (H2TPP) and its chemically prepared diacid dispersed in polymethylcyanoacrylate (PMCA). Photoexcitation of the neutral porphine by laser light leads irreversibly to the formation of the diacid, with the π‐cation radical as intermediate species. Resonance Raman (RR) spectra of the diacid dispersed in the polymer obtained with 441.6 nm in the wavenumber region of 100–1650 cm−1 are recorded. Wavenumbers with other excitation lines are also reported for the diacid species. Some bands assigned to out‐of‐plane vibrational modes and forbidden under ideal D2h symmetry are also observed in the resonance Raman spectra of the diacid. These bands arise from the out‐of‐plane distortions, which reduce the symmetry of the molecule. These findings are supported by the electronic absorption studies of the diacid in the polymer. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
94.
Vaneet K. Sharma Sonam Bansal Ashok K. Malik † Rakesh K. Mahajan 《International journal of environmental analytical chemistry》2013,93(14-15):1105-1110
A procedure has been developed for the direct fourth derivative spectrophotometric determination of zinc(II) dimethyldithiocarbamate by converting it into its copper(II) dimethyldithiocarbamate complex, which is then dissolved in Triton X-100. Beer's law is obeyed over the concentration range 0.5–30?µg/mL in the final solution. Various parameters such as the effect of pH and the interference of a number of ions on the determination of Ziram have been studied in detail. The method is sensitive and can be used for the determination of Ziram in commercial samples like Zirax and Ziron containing Ziram and from wheat grains. 相似文献
95.
96.
Experimental densities (ρ), viscosities (η), and speeds of sound (u) of the binary mixtures of n-dodecane with an alkan-1-ol (hexan-1-ol, heptan-1-ol, octan-1-ol) or an alkan-2-ol (hexan-2-ol, heptan-2-ol and octan-2-ol) were measured over the whole mixture composition range at T = 298.15 K. From these data, the excess molar volume ( $ V_{\text{m}}^{\text{E}} $ V m E ), deviations in viscosity (Δη), and excess isentropic compressibility ( $ \kappa_{S}^{\text{E}} $ κ S E ) have been calculated. The results were fitted by means of the Redlich–Kister equation, in order to estimate the binary coefficients and standard errors. Differences among these binary systems are ascribed to the different association abilities of the alkan-1-ols and alkan-2-ols. Experimental data on the constituted binaries were analyzed using McAllister’s multi-body interaction model, the Jouyban–Acree model, the Prigogine–Flory–Patterson theory, and the Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behavior among the mixtures. 相似文献
97.
Hitendra S. Mahajan Mayur H. Pingale Kapil M. Agrawal 《Journal of inclusion phenomena and macrocyclic chemistry》2013,76(3-4):467-472
The objective of the present study was to formulate inclusion complex of saquinavir mesylate to improve the aqueous solubility and dissolution rate. Saquinavir mesylate is a BCS class II drug having low aqueous solubility and therefore low oral bioavailability. In the present study, inclusion complex of saquinavir mesylate with hydroxypropyl-β-cyclodextrin were prepared by kneading method. Inclusion complex were characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), 1H NMR studies, and Fourier transform infrared spectroscopy and evaluated for in vitro dissolution, and phase solubility studies. DSC and XRD study demonstrated that there was a significant decrease in crystallinity of pure drug present in inclusion complex, which resulted in an increased dissolution rate of saquinavir mesylate and 1H NMR studies strongly, confirmed that the inclusion complex has formed. Inclusion complexation results in improvement in solubility and dissolution rate. The inclusion complexation would be suitable method for dissolution and bioavailability enhancement of saquinavir mesylate. 相似文献
98.
Monika Swami Karuna Mahajan Neeti Gupta R. V. Singh Sunita Arya Sonalika Kushwah 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):2125-2139
The present article describes the synthesis and characterization of tetracoordinated boron (III) complexes with monobasic bidentate ligands (L 1 H, L 2 H, L 3 H, L 4 H, L 5 H, and L 6 H) having the general formulae PhB(L)(OH) and PhB(L) 2 . The 1:1 and 1:2 reactions of phenyl boronic acid with monobasic bidentate ligands resulted in the formation of colored solids. The complexes have been characterized by elemental analysis, molecular weight determinations, and IR and NMR ( 1 H, 13 C and 11 B) spectroscopy, as well as UV-vis spectral studies. Based on these studies, a tetrahedral geometry has been proposed for the resulting complexes. The ligands, along with their complexes, have been screened in vitro against a number of pathogenic fungal and bacterial strains. The studies indicate that the boron chelates are more potent than the parent ligands. 相似文献
99.
Karuna Mahajan Monika Swami R. V. Singh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2664-2679
Tetra- and pentacoordinated antimony and bismuth derivatives have been prepared by the interactions of monophenylantimonydichloride(III), trichlorostibane, and trichlorobismuthane with the sodium salts of 3-(indolin-2-one)hydrazinecarbothioamide (L1H) and 3-(indolin-2-one)hydrazinecarboxamide (L2H), under microwave irradiation as well as by conventional heating. These compounds were further characterized by analytical and spectroscopic techniques including UV, IR, 1H NMR, and 13C NMR spectra. Newly synthesized complexes with their corresponding ligands were also tested for their antifungal and antibacterial activities. 相似文献
100.
Sachini Rodrigo Disni Gunasekera Jyoti P. Mahajan Long Luo 《Current Opinion in Electrochemistry》2021
Electrochemical organic synthesis has recently attracted much attention because of its unique reactivity and environmentally benign approach. Conventional electrosynthesis uses either constant current or constant potential, known as direct current electrolysis. However, recently, alternating current electrolysis has begun receiving more attention. The purpose of this study is to give a short overview of the history and recent advances in the field of alternating current electrolysis for organic synthesis. 相似文献