Materials Literature
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This paper reports the synthesis and physical properties of a novel aromatic polymer which contains the tridentate 2,6-bis(benzimidazol-2-yl)pyridine moiety. It was found that the polymer exhibits different luminescence properties in solution and in the solid state because of the formation of polymer aggregates. Upon…
A novel 2-perfluoroalkyl-activated bisfluoro monomer has been synthesized successfully using a Pd(0)-catalyzed cross-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4‘-dibromodiphenylbenzene. This monomer was converted to novel poly(aryl ether)s by nucleophilic displacement of the fluorine a…
The occurrence of barium sulfate scale (BaSO 4 ) is a severe problem and its associated environmental concerns in oil and gas production worldwide will cause considerable production losses. Chemical dissolution will create a new direction for controlling the scale deposits by chelating agents, which form strong comple…
The aenigmatite-rhonite mineral group consists of eight minerals: Aenigmatite, rhonite, serendibite, krinovite, welshite, dorrite, wilkinsonite and hogtuavite. The general chemical formula of the minerals in this group may be written as {X2} [Y6] (Z6) O 20 , with {X} eightfold coordinated Na (super +) , Ca (super 2+)…
A synthetic access to the first members of expanded corroles 1 and 2 is achieved through formation of two direct pyrrole−pyrrole links by an oxidative coupling reaction. Spectroscopic and structural analysis reveal that 1 and 2 are 22Π aromatic macrocycles despite the nonplanar structure and properties resemble that o…
Interactions of the water-soluble tetra(4-sulfonatophenyl)porphyrin (TPPS 4 ) with ionic micelles in aqueous solutions have been studied by optical absorption, fluorescence, resonance light-scattering (RLS), and 1 H NMR spectroscopies. The presence of three different species of TPPS 4 in cationic cetyltrimethylammoniu…
Hollow polyelectrolyte capsules were fabricated by means of stepwise adsorption of polyelectrolytes followed by dissolution of the templating core. The capsule wall thickness was approximately 20 nm. The diameter of the capsules is given by the size of the templates (3.3 μm). These capsules exclude poly(styrenesulfona…
A theoretical analysis of the scattering of plane-wave atomic excitations in disordered solids has been made in terms of the spectral densities. Hybridization between transverse and longitudinal waves of approximately the same frequency is demonstrated. The analytic results agree well with the results obtained from co…
The transmission of conductance modes in atom-size gold contacts is investigated by simultaneously measuring conductance and shot noise. The results give unambiguous evidence that the current in the smallest gold contacts is mostly carried by nearly fully transmitted modes. In particular, for a single-atom contact the…
Investigations have been carried out to probe the interactions between double-stranded DNA and amine-terminated, ethylenediamine core polyamidoamine starburst dendrimers generation 2 (G2), generation 4 (G4), and generation 7 (G7). Ethidium bromide is used as a fluorescent probe for this study. Under our experimental c…
We report in this paper a procedure to simulate the deposit of carbon diamondlike films over the Si(001) surface. We use the method of tight-binding molecular dynamics and well-known transferable C-C and Si-Si interactions. We propose for the Si-C interaction a weighted average of the single element interactions and t…
The title compound, C19HI8FeN2 or [Fe(CsHs)(CI4HI3-N2)], crystallizes in space group P2~/n with two molecules in the asymmetric unit. The pyrrole groups take part in intermolecular (pyrrole)N--H...Tr(pyrrole) interactions through a hydrogen-bonded ring system involving four pyrrole groups, with N..-(pyrrole centroid)…
An analytical function is presented of the measurable structure factor of a multi-species polydisperse Percus-Yevick fluid consisting of spherical particles with Schulz distributed diameters. As a demonstration, polydispersity effects on some structural properties in the single species polydisperse fluid are investiga…
The photobleaching process has been studied systematically in poly(methylphenylsilane) thin films with thickness comparable to or less than the penetration depth of incident ultraviolet light. It is found out that the photoscission of σ bonds proceeds from longer segments of Si chains to shorter segments, which has be…
The electronic structure of the ${\mathrm{TaB}}_{2}(0001)$ surface, which is terminated by graphitic boron layer has been investigated by angle-resolved ultraviolet photoelectron spectroscopy and first-principles self-consistent-charge discrete variational-$X\ensuremath{\alpha}$ calculations. The occurrence of the cha…
A spiro orthoester having an ester moiety, 2-acetoxymethyl-1,4,6-trioxaspiro[4.6]undecane (4) was synthesized, and its cationic polymerization and depolymerization of the obtained polymer (5) were carried out. The monomer 4 underwent cationic polymerization with a cationic catalyst to afford the corresponding poly(cyc…
Defects and amorphous C layers or clusters in a type-Ib diamond formed by C- or P-ion implantation under certain doses are clearly annealed or epitaxially crystallized during thermal annealing at 750 \ifmmode^\circ\else\textdegree\fi{}C or during mega-electron-volt (MeV) ion-beam irradiation at 750 \ifmmode^\circ\else…
The kinetics of forward and backward energy transfer processes in fluoroindate glasses double doped with Yb3+ and Er3+ has been studied. It was possible to excite selectively Yb3+ ions and detect emission due only to these ions or combined with the emission coming from the Er3+ ions. At low concentration of Yb3+ (0.1…
Ethylene and linear, nonconjugated dienes were copolymerized with the catalyst system Cp2ZrCl2/methylaluminoxane (MAO). The comonomer incorporation and the relationships between structure and properties were evaluated by NMR and by thermal techniques, especially the segregation fractionation technique (SFT) using DSC…
Atomic and electronic structures of intrinsic point defects in yttrium oxysulfides $({\mathrm{Y}}_{2}{\mathrm{O}}_{2}\mathrm{S})$ are studied by first-principles total-energy calculations based on density-functional theory combined with normconserving pseudopotentials. Energetics of all the intrinsic point defects are…