Trions in a periodic potential

The group-theoretical classification of trion states is presented. It is based on considerations of products of irreducible representations of the 2D translation group. For a given BvK period N degeneracy of obtained states is N^2. Trions consist of two identical particles so the symmetrization of states with respect to particles transposition is considered. Completely antisymmetric states can be constructed by introducing antisymmetric spin functions. Two symmetry adapted bases are considered. The third possibility is postponed for the further investigations.Comment: revtex, 5 p., sub. to Physica

Stimulation of macromolecular synthesis by ascorbate in Neurospora

Stimulation of macromolecular synthesis by ascorbat

Role of Silicon in Boron Potassium Nitrate System.

To examine the possibility of improving the ignition characteristics of the commonly used pyrotechnic ignition system based on B-KNO/sub -Binder (30:70:10), B was gradually replaced by Si in its composition. The addition of Si was found to reduce the maximum pressure find increase the ignition delay. Maximum dp/dr value was observed with the composition containing 5 per cent Si. The differential thermal analysis results showed single sharp peaks for ignition in the temperature range 500-570 degreeC. The heat of combustion and burning rate decreased with increase in Si content. Impact sensitivity of the compositions increased with increase in the percentage of Si, whereas no change was observed in the friction sensitivity in comparison with the base composition

Extractive Spectrophotometric Determination of Ce(IV) with p-Anisidine

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Matter-positronium interaction: An exact diagonalization study of the He atom - positronium system

The many-body system comprising a He nucleus, three electrons, and a positron has been studied using the exact diagonalization technique. The purpose has been to clarify to which extent the system can be considered as a distinguishable positronium (Ps) atom interacting with a He atom and, thereby, to pave the way to a practical atomistic modeling of Ps states and annihilation in matter. The maximum value of the distance between the positron and the nucleus is constrained and the Ps atom at different distances from the nucleus is identified from the electron and positron densities, as well as from the electron-positron distance and center-of-mass distributions. The polarization of the Ps atom increases as its distance from the nucleus decreases. A depletion of the He electron density, particularly large at low density values, has been observed. The ortho-Ps pick-off annihilation rate calculated as the overlap of the positron and the free He electron densities has to be corrected for the observed depletion, specially at large pores/voids.Comment: 18 pages, 8 figure

Polymethyl Methacrylate as a Binder for Pyrotechnic Compositions

Studies on polymethyl methacrylate (PMMA) as a binder for igniter and delay compositions are reported. Igniter compositions based on magnesium and boron as fuels and potassium nitrate as oxidiser, delay compositions comprising ferrosilicon and red lead, have been investigated. These compositions were subjected to various tests, such as linear burning rate, sensitivity, calorimetric value, compatibility, pelleting properties, spark sensitivity, ignition temperatures and performance characteristics. The results indicate that the igniter compositions Mg:KNO/sub 3/:PMMA (42:50:8) and B:KNO/sub 3/:PMMA (30:70:10) as well as the delay composition comprising FeSi:Pb/sub 3/O/sub 4:PMMA (25:75:1) have improved properties and therefore could find practical applications

Sintering characteristics of manganese ore fines from Balaghat and Ukwa mines of Manganese Ore (India) Limited

Indian manganese ore reserves are depleting very fast Manganese ore (India) Ltd. realised that utilisation of Manganese ore fines will pave the way for conservation of lumpy high grade manganese ore. Manganese ore fines generated at Balaghat and Ukwa mines of MOIL were subjected to sintering studies at the R&D Centre of Paramount Sinters Pvt. Ltd. The studies indicated that fluxed sinter with very good strength and porosity could be produced. The sinters showed a high degree of reduction and even metalization was noticed. The chemical and physical characteristics indicated that sinters can be used in ferro manganese furnaces. Advantages of using sinter in the ferro alloy manufacture has been highlighted in this report. The authors have conc-luded that from the point of view of conservation and reduction of manufacturing cost, sintering has a vital role to play in ferro alloy industries

Genome analysis of amaranths: determination of inter- and intra-species variations

Amaranths are an important group of plants and include grain, vegetable and ornamental types. Despite the economic importance of the amaranths, there is very little information available about the extent and nature of genetic diversity present in the genus Amaranthus at molecular level. We now report the randomly amplified polymorphic DNA (RAPD) profiles of different species of Amaranthus as well as different accessions of the species. These RAPD analyses have been carried out using 65 arbitrary sequence decamer primers. From the RAPD data, an UPGMA dendrogram illustrating the inter-as well as intra-species relationships has been computed. The putative hybrid origin of A.dubious from A. hybridus and A. spinosus is also ruled out by the RAPD data. The trends of species relationships amongst the amaranths determined by RAPDs is consistent with their cytogenetic and evolutionary relationships that have already been determined