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81.
Phase pure AlPO4 with the AlPO4-18 (AEI) structure was synthesised using N,N-diisopropylethyla-mine as a template. Using a combination of X-ray powder diffraction and computational methods, the location and orientation of the N,N-diisopropylethylamine molecules inside the cages of the AEI structure were determined. Thermogravimetric analysis confirmed that the number of template molecules per unit cell was consistent with the diffraction study. We unequivocally show that only one template molecule is present in each cage of the crystalline AEI material. Our work demon-strates that a combined approach enables accurate structure resolution of such complex materials. 相似文献
82.
We present the results of a study of structural, electronic, and optical properties of the unpassivated and H-passivated GaN nanowires having diameters in the range of 3.29 to 18.33 Å grown along [001] direction by employing the first-principles pseudopotential method within density functional theory in the local density approximation. Two types of nanowires having hexagonal and triangular cross-sections have been investigated. The binding energy increases with the diameter of the nanowire because of a decrease in the relative number of the unsaturated surface bonds. The binding energies of the triangular cross-sectional nanowires are somewhat smaller than those of the hexagonal cross-sectional nanowires in accordance with the Wulff’s rule except the smallest diameter triangular cross-sectional nanowire, where the binding energy is comparable with the corresponding hexagonal cross-sectional nanowires. The band gap varies rapidly with the diameter of the nanowire in the case of the smaller diameter nanowires, and quite slowly for the larger diameter nanowires. After atomic relaxation, appreciable distortion occurs in the nanowires, where the chains of Ga- and N-atoms are curved in different directions. These distortions are reduced with the diameters of the nanowires. The optical absorption in the GaN nanowires is quite strong in the ultra-violet region but an appreciable absorption is also present in the visible region for the larger diameter nanowires. The present results indicate the possibility of engineering the properties of nanowires by manipulating their diameter and surface structure. The presently predicted smaller diameter GaN nanowire possessing the triangular cross-section should be observable in the experiments. 相似文献
83.
Dr. Aloysius Siriwardena Kiran Kumar Pulukuri Pancham S. Kandiyal Dr. Saumya Roy Dr. Omprakash Bande Dr. Subhash Ghosh Dr. José Manuel Garcia Fernández Dr. Fernando Ariel Martin Dr. Jean‐Marc Ghigo Dr. Christophe Beloin Dr. Keigo Ito Dr. Robert J. Woods Dr. Ravi Sankar Ampapathi Dr. Tushar Kanti Chakraborty 《Angewandte Chemie (International ed. in English)》2013,52(39):10221-10226
84.
85.
Bipin Singh Koranga Mohan Narayan S. Uma Sankar 《International Journal of Theoretical Physics》2011,50(3):760-766
The neutrino parameters determined from the solar neutrino data and the anti-neutrino parameters determined from KamLAND reactor
experiment are in good agreement with each other. However, the best fit points of the two sets differ from each other by about
10−5 eV2 in mass-square difference and by about 2° in the mixing angle. Future solar neutrino and reactor anti-neutrino experiments
are likely to reduce the uncertainties in these measurements. This, in turn, can lead to a signal for CPT violation in terms
a non-zero difference between neutrino and anti-neutrino parameters. In this paper, we propose a CPT violating mass matrix
which can give rise to the above differences in both mass-squared difference and mixing angle and study the constraints imposed
by the data on the parameters of the mass matrix. 相似文献
86.
Using quasi-steady-state and time-resolved high-field impedance techniques, the frequency-dependent dielectric permittivity of poly(vinylacetate) has been studied at electric field amplitudes as high as 400 kV/cm. The relative changes of the dielectric loss depend quadratically on the field amplitude and reach about 1 %. The magnitude and frequency-dependence of this non-linear dielectric effect and its time evolution after applying the high field are consistent with energy absorption from the field being at the source of the non-linear behavior. Based upon a phenomenological model of heterogeneous dynamics at isothermal conditions, the observed changes can be explained by locally increased configurational temperatures and the resulting accelerated dynamics. 相似文献
87.
V. N. Prudnikov A. P. Kazakov I. S. Titov Ya. N. Kovarskii N. S. Perov A. B. Granovsky I. Dubenko A. K. Pathak N. Ali J. Gonzalez 《Physics of the Solid State》2011,53(3):490-493
The quasi-diamagnetism effect that manifests itself in the negative magnetic susceptibility observed in weak magnetic fields
during cooling of samples below some critical temperature has been revealed in Ni48Co2Mn35In15 Heusler alloys. The effect has been attributed to a strong nonequilibrium of the system due to the presence of magnetic and
structural disorders and exchange anisotropy. 相似文献
88.
Let F be a field of characteristic other than 2. Let F(2) denotethe compositum over F of all quadratic extensions of F, letF(3) denote the compositum over F(2) of all quadratic extensionsof F(2) that are Galois over F, and let F{3} denote the compositumover F(2) of all quadratic extensions of F(2). This paper showsthat F(3) = F{3} if and only if F is a rigid field, and thatF(3) = K(3) for some extension K of F if and only if F is Pythagoreanand . The proofs depend mainly on the behavior of quadratic forms over quadratic extensions,and the corresponding norm maps. 相似文献
89.
90.
Venkatraman S Anand VG PrabhuRaja V Rath H Sankar J Chandrashekar TK Teng W Senge KR 《Chemical communications (Cambridge, England)》2002,(16):1660-1661
First successful syntheses and structural characterization of new core modified meso aryl azuliporphyrins by a simple [3 + 1] methodology are reported. 相似文献