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121.
An efficient Zn(II)-catalyzed intermolecular double hydroamination of 1,3-enynes with aryl hydrazines, for the synthesis of pyrazolines, has been discussed. 相似文献
122.
123.
Satyawati S. Joshi Prajakta R. Patil Madhav S. Nimase P.P. Bakare 《Journal of nanoparticle research》2006,8(5):635-643
The electrochemical synthesis of alpha Fe2O3 nanoparticles was performed using quaternary ammonium salts viz. TPAB, TBAB and TOAB in an organic medium by optimizing current density and molar concentration of the ligand. The role of ligands in the formation of α phase, structure and magnetic properties was investigated in details. The effect of increasing chain length on the particle size confirmed that as the chain length increases from propyl to octyl, the particle size decreases. X-ray diffraction spectra of as prepared samples and TEM analysis confirmed the amorphous nature of iron oxide. TEM showed beads of iron oxide joined together with a size distribution in the range of 6–30 nm. The Mossbauer studies also support this observation that for the lowest particle size, the line width is broader which successively reduces with increase in particle size. Iron oxide capped with TOAB indicated superparamagnetic nature at room temperature. The resultant internal magnetic field of 506 mm/s due to hyperfine splitting clearly established the formation of α-Fe2O3 The infrared spectroscopy and pH measurements revealed the binding of tetra alkyl ligand with iron oxide. The IR spectra and the increase in basicity of as prepared samples confirmed the formation of hydrated iron oxide. Above 800°C the spectra indicated only iron oxide. Surface area obtained by BET method was 205 m2/g. 相似文献
124.
Dilip P. Patil 《manuscripta mathematica》1993,80(1):239-248
LetO be a monomial curve in the affine algebraice-space over a fieldK andP be the relation ideal ofO. ifO is defined by a sequence ofe positive integers somee-1 of which form an arithmetic sequence then we construct a minimal set of generators forP and write an explicit formula for μ(P). 相似文献
125.
JPC – Journal of Planar Chromatography – Modern TLC - A thin-layer chromatographic method with densitometric UV detection at λ = 232 nm has been developed for standardization of... 相似文献
126.
127.
Sujata Patil R. Nagarajan L. C. Gupta C. Godart R. Vijayaraghavan B. D. Padalia 《Hyperfine Interactions》1988,42(1-4):1063-1066
The series Eu2M3Si5 (M=Ni, Cu, Pd, Rh) have been synthesised for the first time. The Ni, Cu, Pd systems form in U2Co3Si5 type structure.151Eu Mössbauer spectroscopy shows that Eu is in valence fluctuating (VF) state in Ni system, while in Cu and Pd systems it is in stable divalent state. These observations are further confirmed by magnetic susceptibility studies. The material Eu2Rh3Si5 shows two lines in the Mössbauer resonance, one of which shows VF behaviour. 相似文献
128.
129.
CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
130.