1,184 research outputs found
Momentum space properties from coordinate space electron density
Electron density and electron momentum density, while independently tractable
experimentally, bear no direct connection without going through the
many-electron wave function. However, invoking a variant of the
constrained-search formulation of density functional theory, we develop a
general scheme (valid for arbitrary external potentials) yielding decent
momentum space properties, starting exclusively from the coordinate space
electron density. Numerical illustration of the scheme is provided for the
closed-shell atomic systems He, Be and Ne and for singlet
electronic excited state for Helium by calculating the Compton profiles and the
expectation values derived from given coordinate space electron
densities.Comment: 4 pages, 1 figur
Supergrassmannian and large N limit of quantum field theory with bosons and fermions
We study a large N_{c} limit of a two-dimensional Yang-Mills theory coupled
to bosons and fermions in the fundamental representation. Extending an approach
due to Rajeev we show that the limiting theory can be described as a classical
Hamiltonian system whose phase space is an infinite-dimensional
supergrassmannian. The linear approximation to the equations of motion and the
constraint yields the 't Hooft equations for the mesonic spectrum. Two other
approximation schemes to the exact equations are discussed.Comment: 24 pages, Latex; v.3 appendix added, typos corrected, to appear in
JM
Growth Stress Induced Tunability of Dielectric Constant in Thin Films
It is demonstrated here that growth stress has a substantial effect on the
dielectric constant of zirconia thin films. The correct combination of
parameters - phase, texture and stress - is shown to yield films with high
dielectric constant and best reported equivalent oxide thickness of 0.8 nm. The
stress effect on dielectric constant is twofold, firstly, by the effect on
phase transitions and secondly by the effect on interatomic distances. We
discuss and explain the physical mechanisms involved in the interplay between
the stress, phase changes and the dielectric constant in detail.Comment: 11 pages, 5 figure
Studies on Aluminothermic Reduction of Manganese ore for Ferro-Manganese Making
It is well known that lowering the carbon content offerro-alloy increases the value of the metal. This grade of ferro-alloy results in lowering the cost of production in steel melting stage. Alurninothermic process produces carbon free ferro-alloys. In this paper, details of investigations onferro-manganese making are given.- Influence ofpre-reduction of manganese ore to Mn7O3 and
Mn .,stage, excess aluminium overstoichiometric requirement, addition of fluxes etc., on metal yield is discussed. Metal yield of 58-64% on 10 kg scale
with alloy composition of Mn-83%, Fe-13%, Si-1.4 to 2%, Al-0.008% and P-0.16% has been successfully achieved at the Laboratory
Physico-Chemical Characterisation of Lateritic Nickel Ores of Sukinda, Orissa
The only nickel ore deposit of significance in India occurs in the chrorniferous ultramafic complex ofSukinda, Orissa. It is a lateritic nickel o re deposit with a reserve of about 150 million tonne having cut-off grade of 0.05% Ni. The processing of this ore is difficult due
to ultrafine nature ofgeothite, low content of nickel in the ore (max. 1.5% Ni), complex intergrowths of goethite with quartz, talc, kaolinite and magnetite and abrupt variation of nickel content in the ores in horizontal and vertical profiles. In this study the results of detailed
investigations to characterise five bulk samples collected
from different sectors of Sukinda-Kansa, TISCO and OMC are discussed.The techniques used for characterisation include
granulometric study, optical microscopy, X-ray diffraction, thermal analysis, scanning electron microscopic, infrared studies, electron probe microanalysis, leaching experiments and chemical analyses.
This study indicates that the nickel is not present as discrete minerals but mostly associated with goethite. Kansa ore has goethite as major mineral (90%) whereas the other samples contain significant amount of free quartz along with variable amount of chromite,hematite,magnetite, talc, serpentine and kaolin. The fine grained goethite is amorphous to quasi-amorphous in nature. Mineralogy and chemistry of the samples indicate that goethite. Fe and Ni are invariably enriched in the finer size fractions. Electron probe microanalyses indicate that nodular goethire and chromite are Ni-poor (<0.2% Ni) whereas lithiophorite and magnetite contain 11% and 0.9% Ni respectively- The results of the sequential leaching studies involving oxalic, sulphuric and hydrochloric acids indicate three types of association of nickel in goethite: a part with amorphous goethite (ferrilivdrite), a part in weak/A- bonded nature and a part as lattice bound state in goethite . The laterite ore is thus proved to be of comple x in nature which creates problem for liberation of the
constituent minerals based on the srnface properties. Classification down to silt size fraction increases the Ni content to about 1.0% in the material. These ores have been succes.sful/v tested on pilot plant scale for extraction of nickel metal by reduction roasting followed
by arnnrotriut)r - atnmonicrcal leaching and electrowinnin
Symmetries of Large N Matrix Models for Closed Strings
We obtain the symmetry algebra of multi-matrix models in the planar large N
limit. We use this algebra to associate these matrix models with quantum spin
chains. In particular, certain multi-matrix models are exactly solved by using
known results of solvable spin chain systems.Comment: 12 pages, 1 eps figure, RevTex, some minor typos in the publised
version are correcte
Renormalization in Quantum Mechanics
We implement the concept of Wilson renormalization in the context of simple
quantum mechanical systems. The attractive inverse square potential leads to a
\b function with a nontrivial ultraviolet stable fixed point and the Hulthen
potential exhibits the crossover phenomenon. We also discuss the implementation
of the Wilson scheme in the broader context of one dimensional potential
problems. The possibility of an analogue of Zamolodchikov's function in
these systems is also discussed.Comment: 16 pages, UR-1310, ER-40685-760. (Additional references included.
Perl module and PISE wrappers for the integrated analysis of sequence data and SNP features
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