Improved estimation of duality gap in binary quadratic programming using a weighted distance measure

We present in this paper an improved estimation of duality gap between binary quadratic program and its Lagrangian dual. More specifically, we obtain this improved estimation using a weighted distance measure between the binary set and certain affine subspace. We show that the optimal weights can be computed by solving a semidefinite programming problem. We further establish a necessary and sufficient condition under which the weighted distance measure gives a strictly tighter estimation of the duality gap than the existing estimations.     

Surface characterization of TEMPO‐oxidized bacterial cellulose

In this study, we focused on the surface character of bacterial cellulose (BC) before and after oxidation mediated by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO).Solid‐state ¹³C NMR, XPS, SEM, contact angle and surface free energy analyses were performed to investigate the effects of various parameters (reaction time and oxidant and catalyst concentrations) on the surface composition, morphology and polarity of the BC. The results provided by the combined use of these techniques showed that hydrogen bonds were disrupted on the BC surface after carboxylation occurred; therefore, the surface of oxidized BC was rougher than that of the original BC, and the surface free energy, especially the polar components, increased after oxidation. Copyright © 2013 John Wiley & Sons, Ltd.     

Binary hairy nanoparticles: Recent progress in theory and simulations

Binary polymer brushes, including mixed homopolymer brushes and diblock copolymer brushes, are an attractive class of environmentally responsive nanostructured materials. Owing to microphase separation of the two chemically distinct components in the brush, multifaceted nanomaterials with functionalized and patterned surfaces can be obtained. This review summarizes recent progress on the theory and simulations related to binary polymer brushes grafted to flat, spherical, and cylindrical substrates, with a focus on patterned morphologies of multifaceted hairy nanoparticles, an intriguing class of hybrid nanostructured particles (e.g., nanospheres and nanorods). In particular, powerful field theory and particle-based simulations suitable for revealing novel structures on these patterned surfaces, including self-consistent field theory and dissipative particle dynamics simulations, are emphasized. The unsolved yet critical issues in this research field, such as dynamic response of binary polymer brushes to environmental stimuli and the hierarchical self-assembly of binary hairy nanoparticles, are briefly discussed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1583–1599     

A class of finite groups with complete character degree graphs

In this paper, we construct a new class of finite groups whose common divisor graphs are complete graphs, while there is no prime dividing all the nontrivial degrees.     

Extraction and separation of lanthanides from aqueous chloride and nitrate media using mixtures of binary extractants based on secondary and tertiary amines

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Coordination compounds of some transition metal ions with new Schiff base ligand derived from dibenzoyl methane. Structural characterization,thermal behavior,molecular structure,antimicrobial, anticancer activity and molecular docking studies

Series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes were prepared with tetradentate Schiff base ligand derived by condensation of 2‐aminophenol with dibenzoylmethane. The novel Schiff base H₂L (2–2′‐((1Z,1Z’)‐(1,3‐diphenyl propane‐1,3 diylidene) bis (azanylylidene) diphenol) and its binary metal complexes were characterized by physicochemical procedures i.e. elemental analysis, FT‐IR, UV–Vis, thermal analyses (TGA/DTG), mass spectrometry, magnetic susceptibility and conductometric measurements. On the basis of these studies, an octahedral geometry for all these complexes was proposed expect Ni(II) complex which had tetrahedral geometry. Molar conductivity values revealed that the complexes were electrolytes except Mn(II), Zn(II) and Cd(II) complexes were non electrolytes. The ligand bound to the metal ions via two azomethine N and two phenolic OH as indicated from the IR and ¹H NMR spectral study. The molecular and electronic structures of H₂L and its zinc complex were optimized theoretically and the quantum chemical parameters were calculated. The antimicrobial activity against a number of bacterial organisms as Streptococcus pneumonia, Bacillus Subtilis, Pseudomonas aeruginosa and Escherichia coli and fungi as Aspergillus fumigates, Syncephalastrum racemosum, Geotricum candidum and Candida albicans by disk diffusion method were screened for the Schiff base and its complexes. The Cd(II) complex has potent antimicrobial activity. Anticancer activity of the Schiff base ligand and its metal complexes were evaluated in human cancer (MCF‐7 cells viability). The Cr(III) complex exhibited higher activity than other complexes and ligand. Molecular docking was used to predict the binding between Schiff base ligand (H₂L) and its Zn(II) complex and the receptors of RNA of amikacin antibiotic (4P20) and human‐DNA‐Topo I complex (1SC7). The docking study provided useful structural information for inhibition studies.     

A Binary System of a Swallow-Tailed and a Double Swallow-Tailed Compound

The geometrical anisotropy in the shape of swallow-tailed ST liquid crystalline molecules results in an extremely strong tendency of an antiparallel order in the short range. Dielectric measurements on a binary system of a ST and a double ST compound show that even at a mole fraction of 0.5 this effect can be observed. The strong deviations from the statistical distribution of the directions of the molecular long axis is caused by the asymmetric repulsive forces and the dipole-dipole interaction.     

Specific features of T-C-P diagrams for binary systems of B-elements

Abstract

The possibility of reaching high pressures gave rise to intense studies of the phase state of substances, their structures, and properties depending on a new thermodynamic parameter-pressure. Characterizing the extensive development of these studies, one should distinguish three stages: (i) the study of polymorphism for elements under high pressure, and the construction of T-P diagrams; (ii) the study of polymorphism for compounds; and (iii) the construction of three-dimensional T- C-P diagrams for binary and multicomponent systems. At present, the first stage is almost completed in the pressure range from ～100 kbar (see Ref. 1) to 1 Mbar. A series of empirical laws have been established that determine the general direction of structural changes for chemical elements with a pressure rise. Thus, for the elements of the B-subgroup of the Periodic Table, the “coordination rule” has been established according to which an increase in pressure produces structural changes in B elements characterized by a higher packing density and coordination number. According to another rule, the so-called homology rule, B-elements under pressure acquire structures typical for their heavier homologues at normal pressure. These rules manifest themselves most clearly for the elements of the IVB subgroup. In a C-Si-Ge-Sn row structure types change with an increase of the coordination number as follows: graphite (3)-diamond (4)-white tin (6). The same sequence is also observed for the elements of the M3 subgroup with a pressure rise: graphite transforms into diamond, and the diamond-like structure of germanium and silicon transforms into the white-tin structure.