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71.
Mukund P. Sibi Chad C. Stessman Jeffrey A. Schultz James W. Christensen Jianliang Lu Mali Marvin 《合成通讯》2013,43(8):1255-1264
Carboxylic acids can be converted to their corresponding N-methoxy-N-methylamides in high yields using 2-chloro-1-methylpyridinium iodide as the coupling agent. The reaction proceeds without racemization when chiral carboxylic acids are used as the starting material. 相似文献
72.
Mukund G. Kulkarni Sanjay W. Chavhan Mayur P. Desai Yunnus B. Shaikh Dnyaneshwar D. Gaikwad Attrimuni P. Dhondge Ajit S. Borhade Vijay B. Ningdale Deekshaputra R. Birhade Nagorao R. Dhatrak 《Tetrahedron letters》2010,51(34):4494-6381
Application of Wittig olefination-Claisen rearrangement protocol for the short synthesis of furo[2,3-b]indoles is described. 相似文献
73.
A theoretical framework for treating the effects of magnetic fieldH on the pairing theory of superconductivity is considered, where the field is taken in an arbitrary direction with respect
to crystal axes. This is applicable to closed, as well as open normal state Fermi surface (FS), including simple layered metals.
The orbital effects of the magnetic field are treated semiclassically while retaining the full anisotropic paramagnetic contribution.
Explicit calculations are presented in the limits |H| → |H
c2(T)|,T ∼ 0 andT →T
c(|H|), |H| ∼ 0. Effects of weak nonmagnetic impurity scattering, without vertex corrections, have also been taken into account in a
phenomenological way. The final results for the case of open FS and layered materials are found to differ considerably from
those of the closed FS. For example, an important parameter,h(T=0)=|Hc2(0)|/[-Tδ|H
c2
T|δT]T{s0} for the case of a FS open ink
z-direction with thek
z-bandwidth, 4t
3, very small compared to the Fermi energy,E
F, is close to 0.5906, compared to 0.7273 for the closed FS, in the clean limit. Analytical results are given for the magnetic
field dependence ofT
c and the temperature dependence of H
c2 for a model of layered superconductors with widely open FS. For a set of band structure parameters for YBa2Cu3O7 used elsewhere, we find reasonable values for the upper critical fieldH
c2(0), the slope (dH
c2/dT)T
c0, anisotropic coherence lengths ζi(T=0),i=x, y, z, and (dT
c/d|H|)|H| → 0. 相似文献
74.
The phonon dispersion curves for aluminium arsenide and antimonide have been investigated by using a deformation bond approximation
model. The results obtained from this model are compared with the experimental values wherever it is available. Since there
is no complete experimental phonon dispersion curves for AlAs, we could not compare our calculated results, but the results
of AlSb have been compared with the inelastic neutron scattering measurements at 15 K. However, we compare the phonon frequencies
of AlAs and AlSb at critical points of the Brillouin zone obtained by our calculations and Raman spectroscopy measurements.
This model predicts the phonon modes satisfactorily in all the symmetry directions of the Brillouin zone (BZ). The spectrum
has similar features as observed in other III–V compound semiconductors. 相似文献
75.
Mukund G Kulkarni Aniruddha K DokeSaryu I Davawala Ajit V Doke 《Tetrahedron letters》2003,44(26):4913-4914
An efficient one-step synthesis of divinyl ethers from aldehydes and ketones using Wittig olefination is described. 相似文献
76.
B. K. Jha 《Heat and Mass Transfer》1997,33(3):261-263
An analytical study is made to examine the flow behaviour of a fully developed transient free-convective flow of an incompressible
viscous fluid between two heated vertical walls in a porous system. A Laplace transform technique has been employed to obtain
the expression for velocity, temperature and skin-friction. The influence of the various parameters, entering into the problem,
on the velocity field and skin-friction is discussed in detail.
Received on 11 March 1997 相似文献
77.
Lattice vibrational properties of uranium pnictides have been studied using breathing shell model (BSM) which includes breathing
motion of electrons of the U-atoms due tof−d hybridization. The phonon dispersion curves of U-pnicitides calculated from the present model agree reasonably well with
the measured data. A comparison has been made between BSM and our results reported earlier obtained from three-body force
rigid ion model to reveal the importance of the short-range electron-phonon interactions in these compounds. We also report,
for the first time, the two phonon density of states and specific heat for these compounds. 相似文献
78.
79.
80.
N. Kumar S. K. Jha S. S. Chaturvedi 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(3):525-533
Radiation dose-risk assessment was carried out for cereal species Brassica compestris var. dichotoma, Oryza sativa var. Shalum1, Zea mays, Lactuca indica, Cumunis sativum, and Clocasia esculanta due to naturally available radionuclides 40K, 238U and 232Th in Domiasiat area. The activity in biota and corresponding soil was measured by precipitation method using NaI(TI) detector.
Transfer factor (TF) was for Oryza spp. (1.00E−01-40K, 8.76E−05-232Th, and 9.11E−05-238U), for Brassica spp. (5.39E−01-40K, 8.17E−04-232Th and 2.96E−04-238U) and for Zea spp. (3.41E−01-40K, 5.84E−05-232Th, 8.87E−05-238U) etc., respectively. A detailed physio-morphological study of the biota and extensive investigation of ecosystem was carried
out for assessment. The data was modeled using FASSET for dose estimation and obtained total dose was 1.58E−04
\upmu Gy h-1 \upmu \hbox{Gy}\,h^{-1} in Oryza spp., 2.87E−04
\upmu Gy h-1 \upmu \hbox{Gy}\,h^{-1}
Brassica spp. and 6.90E−03
\upmu Gy h-1 \upmu \hbox{Gy}\,h^{-1} in Zea spp. etc. The dose was compared with the UNSCEAR dataset for screening level dose for biota. Zea spp. was more susceptible for the chronic radiation exposure. 相似文献