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101.
B. Subrahmanyam G. Venkateshwerlu D. D. Patnaik E. Padmavathi Reddy 《Journal of Chemical Sciences》1980,89(3):219-223
The infrared spectra of substituted ω-bromoacetophenones were recorded in solvents of varied dielectric constants. All the
compounds exhibited two carbonyl bands. The splitting of the bands was attributed to existence of rotomers. The higher and
lower frequency bands were assigned to cis and gauche conformations respectively. A linear plot was obtained between the frequencies
of the bands and Hammett σ constants. The ratio of the cis and gauche conformers increased with increase in the dielectric
constant of the solvent. The results suggest that the relative stabilities of the conformers are determined by the electrostatic
repulsion between the C=O and C-Br dipoles in the cis form and electrostatic attraction between negative bromine atom and
the carbon atom para to the ring substituent which is rendered positive by the electron withdrawing groups. 相似文献
102.
103.
Zeitschrift für Physik A Hadrons and nuclei - An experiment which allows measurement of a collective scattering spectrum of a plasma in the forward direction (7°) in a single discharge is... 相似文献
104.
S.J. Singh J. Prakash S. Patnaik A.K. Ganguli 《Physica C: Superconductivity and its Applications》2010,470(21):1928-1932
Electron-doping of the semimetal (CeOFeAs) by either fluorine (max Tc ∼ 43 K) or cobalt (max Tc ∼ 11 K) leads to superconductivity. Here we show the effect of transition metal (Co) substitution at the iron site on the superconducting properties of CeO0.9F0.1FeAs (Tc ∼ 38 K) to understand the interplay of charge carriers in both the rare earth-oxygen and Fe–As layers. Simultaneous doping of equivalent number of charge carriers in both layers leads to a Tc of 9.8 K which is lower than the Tc obtained when either the conducting layer (FeAs) or charge reservoir layer (CeO) is individually doped. This suggests a clear interplay between the two layers to control the superconductivity. Resistivity upturn and negative magnetoresistance are observed with Co doping that is interpreted in the gamut of Kondo effect. Hall coefficient and thermoelectric power indicate increased carrier concentration with cobalt doping in CeO0.9F0.1FeAs. The rf penetration depth both for CeO0.9F0.1Fe0.95Co0.05As and CeO0.9F0.1FeAs show an exponential temperature dependence with gap values of ∼1.6 and 1.9 meV respectively. 相似文献
105.
S.J. Singh J. Prakash S. Patnaik A.K. Ganguli 《Physica C: Superconductivity and its Applications》2010,470(11-12):511-515
The effect of yttrium substitution at the lanthanum site on the superconducting properties of La1?xYxO0.9F0.1FeAs (‘x’ = 0, 0.10, 0.20, 0.30, 0.50 and 0.60) oxypnictides has been studied. Powder X-ray diffraction studies confirm single phases till x = 0.1 beyond which minor amount of Y2O3 is observed. The temperature dependence of resistivity measurements confirm the superconducting transition temperature (Tc) of 34.8 (±0.05) K and corresponding Meissner transition at 34.3 K in the ‘x’ = 0.3 composition which is higher than that reported for the parent phase (LaO0.9F0.1FeAs (Tc = 28 K)). Further increase in the concentration of yttrium leads to broadening and suppression of the superconducting transition. The value of Hc2 at zero temperature is estimated to be about 60.5 T. The Seebeck coefficient (S) shows a negative sign indicating that the major contribution to the conductivity is by electrons. The Hall coefficient (RH) also remains negative throughout the temperature range supporting the thermopower results. The lattice parameters (a and c) decreases and the charge-carrier density increases with yttrium doping. 相似文献
106.
107.
Asit Ray Sudipta Jena Basudeba Kar Jeetendranath Patnaik Pratap Chandra Panda 《Natural product research》2019,33(10):1482-1485
The chemical constituents of the essential oils hydrodistilled from rhizome parts of Hedychium greenii W.W. Sm. and Hedychium gracile Roxb, of family Zingiberaceae, growing in India, were analysed for the first time by GC-FID and GC-MS, respectively. A total of 30 and 29 components representing 99.62 and 96.74% of the total oil were identified in the essential oils of H. greenii and H. gracile, respectively. The major components of H. greenii were bornyl acetate (31.32%), α-pinene (14.49%), camphene (12.81%) and limonene (10.55%), whereas H. gracile was dominated by β-pinene (25.24%), γ-terpinene (24.62%), terpinen-4-ol (14.87%) and 1,8-cineole (7.51%). Essential oils were assessed for antioxidant potential using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay. H. greenii oil exhibited stronger antioxidant potential as compared to H. gracile oil and butylated hydroxytoluene (BHT). Thus, H. greenii rhizome oil has the potential to be used as an alternative source of antioxidant. 相似文献
108.
Flux flow of Abrikosov-Josephson vortices along grain boundaries in high-temperature superconductors
Gurevich A Rzchowski MS Daniels G Patnaik S Hinaus BM Carillo F Tafuri F Larbalestier DC 《Physical review letters》2002,88(9):097001
Low-angle grain boundaries (GBs) in superconductors exhibit intermediate Abrikosov vortices with Josephson cores, whose length l along GB is smaller than the London penetration depth, but larger than the coherence length. We found an exact solution for a periodic vortex structure moving along GBs in a magnetic field H and calculated the flux flow resistivity R(F)(H), and the nonlinear voltage-current characteristics. The predicted R(F)(H) dependence describes well our experimental data on 7 unirradiated and irradiated YBa(2)Cu(3)O(7) bicrystals, from which the core size l(T), and the intrinsic depairing density J(b)(T) on nanoscales of a few GB dislocations were measured for the first time. The observed J(b)(T) = J(b0)(1-T/T(c))(2) indicates a significant order parameter suppression on GB. 相似文献
109.
R. B. Sharma A. Patnaik S. P. Mishra 《Journal of Radioanalytical and Nuclear Chemistry》1985,94(1):33-43
The thermal annealing of the damage caused by /n,/ reaction has been investigated for anhydrous copper iodate in crystalline phase. Solvent extraction and fractional precipitation methods were employed to distinguish the recoil species containing recoil iodine-128 atoms. The role of reaction intermediates have been discussed. 相似文献
110.
On the basis of crossing symmetry a new set of exact relations involving theππ partial wave amplitudes have been derived, using Roskies’ amplitudes. 相似文献