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991.
D. Bharathi Mohan K. Sreejith C.S. Sunandana 《Applied physics. B, Lasers and optics》2007,89(1):59-63
Silver thin films in the thickness range 2–10 nm produced by thermal evaporation onto glass substrates were systematically
iodized and carefully characterized by X-ray diffraction, atomic force microscopy (AFM) and optical absorption spectroscopy.
While the uniodized films are X-ray amorphous in keeping with their quasi-continuous nature and 2D islanded structure, briefly
iodized films showed characteristic beta AgI structure. Most interestingly, AFM of Ag films revealed uniform triangle-shaped
embryos whose shape does not change appreciably upon iodization. Optical absorption spectra of uniodized Ag films show intense
surface plasmon resonance (SPR) features with maxima at 440, 484 and 498 nm for the films of thicknesses 2, 5 and 10 nm, respectively,
with 5 nm films showing properties characteristic of optimally matched dielectric and electronic properties of the substrate
and sample, respectively. Finally, an interesting and unique SPR–exciton phase transition is observed as the ultra-thin films
are progressively iodized. These Ag and AgI films could be promising candidates for plasmonic and nanophotonic applications.
PACS 78.66.-w; 73.20.Mf; 71.35.Cc; 42.70; 68.37.Ps; 42.82.-m 相似文献
992.
The high-energy Glauber approximation is used to derive the formula for scattering amplitude for ionization of helium atom by electron impact. The scattering amplitude is expressed as a one dimensional integral involving MeijerG-functions. This may further be expressed in a closed form as simple sums of Meijer functions by writing down the series expansion for Bessel and Meijer functions. Further, the asymptotic behaviour of these amplitudes is examined for both large and small momentum transfers. 相似文献
993.
994.
Peter van de Weijer Chandra Mohan Dirk M. W. van den Ham 《Magnetic resonance in chemistry : MRC》1977,10(1):165-168
The 13C n.m.r. spectra of the N-methylated mono- and diazanaphthalenes have been recorded and analysed. It has been shown that N-methylation as well as N-protonation in cinnoline occur predominantly at the β-nitrogen atom. N-methylation and N-protonation show a similar effect on the 13C chemical shifts. 相似文献
995.
N. V. Gopalakrishnan 《Proceedings Mathematical Sciences》1970,71(5):242-256
The fraction of energy transferred to the neutral pions ( \( K_{\pi ^ \circ } \) ), in an interaction of high energy (> 20 GeV) N-particles (nucleons and pions) with atomic nuclei, is estimated from the data collected, using a total absorption spectrometer (TAS) and a multiplate cloud chamber. The average value of \( K_{\pi ^ \circ } \) ( \( \bar K_{\pi ^ \circ } \) ) is found to be 0·12 ± 0·01 in the energy range 20–100 GeV (ē0 = 35 GeV) and 0·19 ± 0·02 in the region of > 100 GeV (ē0 = 206 GeV). The value of \( \bar K_{\pi ^ \circ } \) obtained in different experiments and its dependence on the primary energy are discussed. An increase in \( \bar K_{\pi ^ \circ } \) in pion-nucleus collisions with the energy of the pion or an increase in the ratio of pions to protons, at 800 gm./cm.2, in the energy range of a few tens of GeV to a few hundred GeV or both is to be invoked to explain the energy dependence of \( \bar K_{\pi ^ \circ } \) observed in this investigation. 相似文献
996.
Mohan S. Putcha 《Semigroup Forum》1973,6(1):12-34
The purpose of this paper is to develop a general theory of semilattice decompositions of semigroups from the point of view
of obtaining theorems of the type: A semigroup S has propertyD if and only if S is a semilattice of semigroups having property β. As such we are able to extend the theories of Clifford
[3], Andersen [1], Croisot [5], Tamura and Kimura [14], Petrich [9], Chrislock [2], Tamura and Shafer [15], Iyengar [7] and
Weissglass and the author [10]. The root of our whole theory is Tamura's semilattice decomposition theorem [12, 13]. Of this,
we give a new proof.
The results of this paper were obtained by the author between January and July of 1971, while an undergraduate at the University
of California, Santa Barbara. 相似文献
997.
The symmetric marching technique developed in [1,2] has been extended to the elliptic equations with variable coefficients involving mixed partial derivatives. The restricted class of such equations of the form uxx+2B(x, y)uxy+c(x,y)uyy=0 have been considered. Numerical results of model problems solved are presented. 相似文献
998.
D.Bharathi Mohan 《Journal of Physics and Chemistry of Solids》2004,65(10):1669-1677
Nanoscale crystallites of Ag-rich (Ag1−xCuxI, x=0.05, 0.10, 0.15 and 0.25), Cu-rich (Cu1-yAgyI, y=0.05, 0.10, 0.15 and 0.25) and intermediate Ag1-xCuxI (x=0.50) solid solutions and end members AgI, CuI with sizes in the range of 46-13 nm were synthesized by attrition at ambient temperature in a soft mechanochemical reaction (MCR) of Ag, Cu and I. Monophasic γ-AgI (zincblende, ) with disordered Ag+ sublattice and the crystallite size of about ∼31 nm was realized in the case of Ag0.75Cu0.25I (x=0.25) composition. Lattice parameter decreases linearly from 649 to 604 pm with increasing Cu concentration in the AgI-CuI system validating Vegard's law. Smallest size (∼13 nm) agglomerated nanocrystals were realized in the Cu-rich composition Cu0.75Ag0.25I (), while unagglomerated uniform-sized (∼17 nm) and spherical shape nanocrystallites of Ag0.50Cu0.50I () with maximum strain were synthesized for sensor applications using MCR. Differential scanning calorimetry study shows the systematic changes in the phase transition temperature with Cu substitution. Ag-rich composition posses less enthalpy (ΔH (x or Cu=0.05, 0.10, 0.15, 0.25)=6.0, 6.11, 6.6, 6.3 in kJ/mol) and entropy (ΔS (y or Ag=0.05, 0.10, 0.15, 0.25)=14.15, 14.1, 15.03, 13.6 in J/mol K) when compared to undoped AgI () implying greater thermal stability of γ-phase due to Cu-strengthened Ag-I bond. Enhanced entropy () in Cu0.75Ag0.25I (Cu-rich) solid solutions relative to CuI () indicates Ag-induced cation disorder. Fifteen percent Ag-doped CuI (Cu0.85Ag0.15I) nanocrystals apparently behave like microscopic p-n junctions with currents in the range of 10−6-10−8 A characterized by a non-linear I-V curve. 相似文献
999.
1000.
Upper and lower bounds on the drag offered to a Newtonian fluid sphere placed in an Ellis model fluid in creeping flow have been found using variational principles. For a solid sphere, the bounds are in good agreement with those reported by earlier investigators. 相似文献