Now we are at the stage of publishing the opening issue of a new volume, volume no. 3 of our journal. For this issue our plan was to publish the follow up papers related to the presentations in the one day national level seminar on Astronomy at our college. Though we received six follow up papers but due to technical reasons, not all of those were ready to publish; however, the papers which were received but not yet ready to bring out in this issue, may be published in future after required modifications. So we have a mixed set of papers, some are related with the seminar and some others are regular ones. In this issue we are publishing six papers in total. Among these two are research articles, three are review articles …
The transport properties of strongly correlated material Na0.75CoO2 has been studied. Both resistivity and thermoelectric power increase with temperature. The change in the slope of resistivity curve at around 20 K is associated with the magnetic transition. In thermopower, there is a kink at around 290 K possibly due to a second-order structural phase transition. The value of thermopower ( 139.4 V/K) and resistivity (2mOhm-cm) at 300 K are good enough for the material to be considered as a good thermoelectric material.
We calculate the free energy, entropy and pressure of the Quark Gluon Plasma (QGP) at finite temperature and density with a given fraction of spin-up and spin-down quarks using a MIT bag model. Within our phenomenological model, we estimate the transition temperature Tc by constructing the phase boundary between the hadronic phase and the QGP phase. Finally, we compute the equation of state of the QGP and its dependence on the temperature and the density.
The discovery of telescope changed forever the way we looked at the Universe. Our idea about space, as was perceived through the naked eye, was revolutionized. The continuous upgrading of the telescopes over the years and subsequent advancements of the sciences of Astronomy and Astrophysics experienced another big leap with the launching of the space telescopes in the 20th century. Now the space could be perceived both through the visible and invisible electromagnetic waves. Launch of “ASTROSAT” by ISRO is perhaps the next possible leap that could be. An overview of all these developments is presented here.
Bidentate ligands with nitrogen and sulphur as potential site for coordination have vast effect on coordination chemistry. Nitrogen as having ‘border line’ property can coordinate with both hard and soft transition metal ions whereas sulphur prefers to bind with soft metal ions. So thiosemicarbazides and their derivatives, having three nitrogen centres and one sulphur donor centre, would bind with all most all metal ions. Several research works have been carried out using thiosemicarbazides and their derivative as ligand to study the mode of coordination of the ligand and to study geometry, spectroscopic behavior, magnetic properties and antibacterial and antitumor activities of the prepared complexes with various transition metals. The present article is to review and summarize such major research works in this area.
Dicyanamide [N(CN)2‾, dca] bridged multinuclear metal complexes are described from the perspective of their structure and magnetism. It has been observed from several reports that dicyanamide can bind one, two or more metal centres with different bridging modes like μ1,μ1,3, μ1,5, μ1,1,5, μ1,3,5 modes and end up with a diverse range of 1D, 2D and 3D coordination polymers. Variable temperature magnetic study shows that depending on the nature of the metal centres some of these compounds show very interesting magnetic interaction through dcabridge. As for example, the neutral binary systems, M(dca)2, form three-dimensional rutile-like structures that exhibit ferromagnetic (M = Co and Ni ), antiferromagnetic (M = Cr, Mn and Fe ) or paramagnetic (M = Cu) ground states. Among the different bridging modes μ1,5 bridging is occurred in most of the cases and aweak antiferromagnetic interaction is operating in these compounds.
The concept of entropy and the spontaneity of a process are the main contents that one encounters while studying the second law of thermodynamics. In this article, a variety of natural phenomena have been discussed which ultimately explains the concept behind the introduction of various physical statements. Also a different approach has been illustrated that may be introduced while explaining the concept of entropy to students.
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