Effect of pre-existing baryon inhomogeneities on the dynamics of quark-hadron transition

Baryon number inhomogeneities may be generated during the epoch when the baryon asymmetry of the universe is produced, e.g. at the electroweak phase transition. These lumps will have a lower temperature than the background. Also the value ofT _c will be different in these regions. Since a first-order quark-hadron (Q–H) transition is susceptible to small changes in temperature, we investigate the effect of the presence of such baryonic lumps on the dynamics of the Q–H transition. We find that the phase transition is delayed in these lumps for significant overdensities. Consequently, we argue that baryon concentration in these regions grows by the end of the transition. We mention some models which may give rise to such high baryon overdensities before the Q–H transition.     

Pressure-volume relations and bulk modulus under pressure of tetrahedral compounds

The pressure-volume relation and the compression effect on the bulk modulus of tetrahedral compounds such as GaP, InP, ZnS, ZnSe, ZnTe and CdTe are investigated from the electronic theory of solids by using our recently presented binding force, which includes mainly covalent interactions in the pseudopotential formalism and partially ionic interactions. The calculated results of the pressure-volume relations involving the pressure-induced phase transition are useful when comparing with the experimental data under high pressure. The calculated bulk modulus of these compounds increases as the crystal volume decreases. Further, the pressure derivative of bulk modulus is not constant and decreases with the reduction of the crystal volume.     

Fluctuation and fractality study of target residue in S32- AgBr interaction at 200 A GeV

In this paper we analysed scaled factorial moment in different phase-space intervals to study the dynamical fluctuation of target evaporated particles in ³²S-AgBr interactions at 200 A GeV. In order to gather knowledge about the detailed characteristics of intermittency behaviour, the SFMs are calculated upto 6th order. The analysis indicates the occurence of a nonthermal phase transition and different aspects of particle production. The multifractility among target evaporated particles is also indicated by the data when analysed using the new method proposed by Takagi.     

Equation of state and compression effect on the bulk modulus of AlP,AlAs and AlSb compounds

The equation of state and the pressure effect on the bulk modulus of AlP, AlAs and AlSb are studied from the electronic theory of solids by using our presented binding force, although not reported experimentally. The obtained results of the pressure-volume relations involving the pressure- induced phase transition are useful to estimate the experimental data of these compounds. The obtained bulk modulus increases with the crystal volume compressed, and the pressure derivative of the bulk modulus for AlP, AlAs and AlSb is estimated theoretically.     

Synthesis and characterization of ruthenium(II) complexes of the NNS-donor Schiff-base derived from 2-methyl-2-(2-pyridyl)benzothiazoline

Transition Metal Chemistry -     

Chaos in a chemical system

Chaotic oscillations have been observed experimentally in dual-frequency oscillator OAP - Ce⁺⁴-BrO^? ₃-H₂SO₄ in CSTR. The system shows variation of oscillating potential and frequencies when it moves from low frequency to high frequency region and vice-versa. It was observed that system bifurcate from low frequency to chaotic regime through periode-2 and period-3 on the other hand system bifurcate from chaotic regime to high frequency oscillation through period-2. It was established that the observed oscillations are chaotic in nature on the basis of next amplitude map and bifurcation sequences.     

Pressure-induced structural transitions in PbI2: A high-pressure Raman and optical absorption study

The effect of pressure on the 2H and 4H polytype of PbI₂ has been investigated by Raman and optical absorption spectroscopy, using the diamond anvil cell. The 2H-polytype undergoes pressure-induced phase transitions at 5 kbar and near 30 kbar. The 4H-polytype exhibits phase transitions near 8 kbar and above 30 kbar. The Raman modes abruptly change at these pressures. The optical absorption edge shifts red at the rate of 15±1 MeV/kbar in the 2H-PbI₂ and at the rate of 7 MeV/kbar in phase II. The latter phase is most likely to possess a 3d-structure and not a layer type. The possible structures for the high pressure phases are discussed.