Solitons at the critical density of negative ions in multicomponentplasmas

The derivation of solitary waves in generalized multicomponent plasmas shows that the negative ion introduces a critical density at which the characteristics of the solitons are studied. The soliton's behavior derived using the Korteweg-deVries (KdV) equation at the critical density shows that the nonlinearity of the wave vanishes. Thus the mode of study is augmented through a modified KdV equation. Using a higher-order equation involving quadratic and cubic nonlinearities, the transition of the KdV equation to a modified KdV equation along with the conservation of the Sagdeev potential, which is not affected by the negative ions, is studied in detail. The results are compared with experimental observations, especially those made by Y. Nakamura et al. (J. Plasma Phys., vol.33, p.237-48, 1985)     

Trans-bis(dimethylglyoximato) cobalt(III) complexes containing imidazole and thiocyanate as axial ligands

Imidazole(Im), benzimidazole(BzIm), morpholine (Morph) and their derivatives react with Co(CNS)₂ and dimethylglyoxime(DH₂) in ethanolic medium in presence of air to form a number of new cobalt(III) complexes of the type trans-[Co(DH)₂(L)(SCN)], which are characterised on the basis of electronic and IR spectra, NMR (¹H and ¹³C) and mass spectra as well as thermogravimetric (TG-DTA) and conductance measurements. The thiocyanate groups are S-bonded. The NMR observations suggest that in solution these compounds exist as mixtures of the neutral species [Co(DH)₂(L)(SCN)] and the salt [Co(DH)₂(SCN)₂]^? [Co(DH)₂(L)₂]⁺. The mass spectra does not show the molecular ion peak of the complex. The TG-DTA measurements show that the thermolysis of these complexes proceeds through polymeric intermediates giving CO₃O₄ as the end product.     

Hartree-Fock cluster investigation of location and hyperfine properties of normal muonium in silicon-trend with respect to diamond

Using the first-principles Hartree-Fock Cluster procedure employed earlier for normal muonium (Mu) in diamond, the total energy and hyperfine field at the muon site in silicon have been studied as a function of muon position along the <111> direction. The muon was found to be localized in the tetrahedral interstitial region, although the potential was significantly shallower as compared to diamond. The vibrationally averaged hyperfine constant for the muon shows a correct trend compared to diamond but is somewhat larger than experiment, possible reasons for which will be discussed. Results for the superhyperfine constants in silicon will be presented and compared with those for diamond.     

Degree of approximation of functions in the Hölder metric by (e,c) means

Degree of approximation of functions by the (e, c) means of its Fourier series in the Hölder metric is studied.     

Low temperature magnetic structure of MnSe

In this paper we report low temperature neutron diffraction studies on MnSe in order to understand the anomalous behaviour of their magnetic and transport properties. Our study indicates that at low temperatures MnSe has two coexisting crystal structures, high temperature NaCl and hexagonal NiAs. NiAs phase appears below 266 K and is antiferromagnetically ordered at all temperatures while the NaCl phase orders antiferromagnetically at 130 K.     

A systematic study of the Toda lattice

We apply the results of our recent investigation of integrable models to the particular case of the Toda lattice. We obtain the conserved quantities in closed form and derive the recursion relation which leads to their involution. We compare our Lax equation with the conventional and present the higher order Lax equations also in a closed form.     

A Graphical Approach to Price-Break Analysis—3

The price-break problem is a non-linear discrete problem of two variables and three parameters which is not solvable analytically. As such, a graphical solution is suggested here by re-formulating the problem in two stages: first, as an equivalent non-linear, and next, as a linear problem of two variables and a single parameter. The later formulation affords an efficient graphical solution which was not possible earlier. In addition, useful procedures for plotting iso-cost curves and deriving approximate numerical solutions are also discussed.     

Shape changes at high spin in 78Kr

High-spin states in ⁷⁸Kr have been studied via the ⁶³Cu (¹⁹F, 2p2n)⁷⁸Kr reaction at a beam energy of 60 MeV using the Indian National Gamma Array (INGA). In this nucleus, lifetimes have been measured upto the I^π=22⁺ level in the yrast positive-parity band and upto the I^π=15^- level in the negative-parity band using the Doppler Shift Attenuation Method (DSAM). The deduced transition quadrupole moments Q_t's are found to decrease with rotational frequency for both the bands.     

Nonlinear fluctuating hydrodynamics and sequence of time scales of relaxation in supercooled liquids

Nonlinear fluctuating hydrodynamic (NFH) models for relaxation in the supercooled liquid are considered. Recent results on self consistent mode coupling theory for the slow relaxation of density fluctuations are analyzed to explain the glassy dynamics. The relaxation mechanisms for different types of models with and without wave vector dependences are discussed. For the schematic models where all wave vector dependences are dropped a sequence of time scales enters the relaxation process. For the non-ergodicity parameter very close to the ideal transition point is scaled by an exponent equal to 1/2. This is demonstrated here through an analysis of the mode-coupling equations for the wave vector dependent models that follow from equations of NFH.