Thermal Entanglement in a Two-Qutrit Spin-1 Anisotropic Heisenberg Model

The negativity (N) as a measure of thermal entanglement (TE) is studied for a two-qutrit spin-1 anisotropic Heisenberg XXZ chain with Dzyaloshinskii-Moriya (DM)...     

Molecular Structure and Supramolecular Architecture of (E)-2-Bromo-6-[(2,4,6-Tribromophenylimino)methyl]-4-Chlorophenol

Crystallography Reports - In this study, the molecular structure and supramolecular architecture of a new compound have been studied in depth using single crystal X-ray diffraction (XRD) technique....     

Ionic liquid functionalized cellulose as an efficient heterogeneous catalyst for the facile and green synthesis of benzoxazine,pyrazine and quinoxaline derivatives in aqueous media

Immobilization of acidic ionic liquid, 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate on cellulose (Cell-[pmim]HSO₄) as an efficient heterogenous catalyst for the simple and environmentally benign synthesis of benzoxazine, pyrazine and quinoxaline derivatives in aqueous media at room temperature is described. The catalyst was characterized by FTIR spectroscopy and X-ray diffraction pattern. This method provides several advantages such as mild reaction conditions, environmentally friendly catalyst, good to excellent yields and simple work-up procedure.     

Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering

Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5 GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(?) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.     

Diterpenoids from Salvia ceratophylla

Salvia ceratophylla L. has yielded four known and two new diterpenoids together with two triterpenic acids, a steroid and a flavone. The structures of the compounds were established by spectroscopic analyses. One of the known compounds candidissiol exhibited a high antibacterial activity against Staphylococcus epidermidis and Proteus mirabilis.     

Synthesis and Biological Activity of Novel (E,E)-vic-dioximes

A novel vic-dioxime ligand containing the thiourea group, (4E,5E)-1,3-bis{4-[(4-methylphenylamino)methyl] phenyl}- 2-thiooxaimidazoline-4,5-dione dioxime, (4) mmdH₂ has been prepared from N,N′-bis{4-[(4-methylphenylamino)methyl]phenyl}thiourea, (3) mft and cyanogen di-N-oxide. Mononuclear [M(mmdH)₂], where M = Ni^II, Co^II and Cu^II complexes of the (4) mmdH₂ bidentate ligand have been obtained with a 1:2 metal:ligand ratio, as do most the vic-dioximes. The complexes are formed by coordination of N, N atoms of the ligand. The vic-dioxime ligand and its some transition metal complexes have been characterized by elemental analyses, molar conductance data, magnetic susceptibility, i.r., ¹H-n.m.r and u.v.–vis. spectroscopy. Conductivity measurements have shown that mononuclear complexes are non-electrolytes. In addition, the ligands and metal complexes were screened for antibacterial and antifungal activities by agar well diffusion techniques using DMF as solvent.     

4‐[(3‐Chloro­phenyl)­diazenyl]‐2‐{[tris(hydroxy­methyl)­methyl]amino­methyl­ene}cyclo­hexa‐3,5‐dien‐1(2H)‐one

The title compound, C₁₇H₁₈ClN₃O₄, adopts the keto–amine tautomeric form and displays an intramolecular N—H⋯O hydrogen bond [N⋯O = 2.639 (2) Å]. The configuration around the azo N=N double bond is trans, and the dihedral angle between the planes of the two aromatic rings is 20.5 (2)°. The mol­ecules are linked by O—H⋯O hydrogen bonds to form a three‐dimensional network.     

Critical and Compensation Temperatures of the Ising Bilayer System Consisting of Spin-1/2 and Spin-1 Atoms

The critical and compensation temperatures of the bilayer Bethe lattices with one of the layers having only spin-1/2 atoms and the other having only spin-1 atoms placed symmetrically are studied by using exact recursion relations in a pairwise approach. The Hamiltonian of the model consist of the bilinear intralayer coupling constants of the two layers J ₁ and J ₂ for the interactions of the atoms in layers with spin-1/2 and spin-1, respectively, and the bilinear interlayer coupling constant J ₃ between the adjacent atoms with spin-1/2 and spin-1 of the layers. After obtaining the ground state phase diagram with J ₁ > 0, the variations of the order-parameters and the free energy are investigated to obtain the phase diagram of the model by considering only the ferromagnetic ordering of the layers, i.e. J ₁ > 0 and J ₂ > 0, and ferromagnetic or antiferromagnetic ordering of the adjacent spins of the layers, J ₃ > 0 or J ₃ < 0, respectively. It was found that the system presents both second- and first-order phase transitions and, tricritical points. The compensation temperatures was also observed for the appropriate values of the system parameters. PACS: 05.50.+q 05.70.Fh 64.60.Cn 75.10.Hk     

Numerical study on local entropy generation in a burner fueled with various fuels

This study considers numerical simulations of the combustions of hydrogen and various hydrocarbons with air, including 21% oxygen and 79% nitrogen, in a burner and the numerical solution of the local entropy generation rate due to the high temperature and velocity gradients in the combustion chamber. The combustion is simulated for the fuel mass flow rates providing the same heat transfer rate to the combustion chamber in the each fuel case. The effects of (only in the case of H₂ fuel) and equivalence ratio () on the combustion and entropy generation rate are investigated for the different (from 5,000 to 10,000 W) and s (from 0.5 to 1.0). The numerical calculation of combustion is performed individually for all cases with the help of the Fluent CFD code. Furthermore, a computer program has been developed to numerically calculate the volumetric entropy generation rate distributions and the other thermodynamic parameters by using the results of the calculations performed with the FLUENT code. The calculations bring out that the maximum reaction rates decrease with the increase of (or the decrease of ). The large positive and negative temperature gradients occur in the axial direction, nonetheless, the increase of significantly reduces them. The calculations bring out also that with the increase of from 0.5 to 1.0, the volumetric local entropy generation rates decrease about 4% and that the merit numbers increase about 16%.