Materials Literature
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A novel regioregular polymer comprising alternating 1,4-phenylene and 3-butyl-2,5-thienylene repeat units has been synthesized and characterized using 1 H NMR, FTIR, UV-VIS absorption and fluorescence emission spectroscopy. The derived polymer showed strong fluorescence with a solution quantum yield of 48% relative to…
The synthesis of novel perfluorovinyl thioacetoxy monomer (FSAc) and its copolymerization with vinylidene fluoride (VDF; also called 1,1-difluoroethylene) are presented. This monomer was obtained in good yield from the photochemical addition of thiol acetic acid to 1,1,2-trifiuoro-1,4-pentadiene. It was first hydrolyz…
Molecular dynamics simulations of the perovskite oxide KNbO 3 are performed with a first-principles effective Hamiltonian. They reveal the prevalence of local polar distortions with short-range chain-like correlations, present even in the paraelectric phase far above T c . The ordering of these dynamically fluctuating…
Several sets of non-standard zero-field splitting (ZFS) parameters in the spin Hamiltonian (SH) for transition-metal ions at orthorhombic or lower symmetry sites in various crystals have been revealed by a recent literature survey. The standardization limits the ratio of the orthorhombic ZFS parameters: (conventional)…
This paper describes a spectroscopic study of the heterogenisation of a novel liquid-phase epoxidation catalyst, a titanium(IV) silsesquioxane complex. Its immobilisation is performed exclusively via a straightforward adsorption of the homogeneous catalyst, i.e. the metal complex, in the pores of an MCM-41 host materi…
Penicillin G acylase is an important enzyme in the commercial production of semisynthetic penicillins used to combat bacterial infections. Mutant strains of Providencia rettgeri were generated from wild-type cultures subjected to nutritional selective pressure. One such mutant, Bro1, was able to use 6-bromohexanamide…
The reaction of an aqueous solution of sodium molybdate with hypophosphorous (phosphinic) acid acting both as reducing agent and ligand at low pH values (≈1) results in the formation of nanosized ring-shaped cluster units which assemble to form layers of the compound Na21[MoVI126- MoV28O462H14(H2O)54(H2PO2)7]·xH2O 1 (…
This paper deals with discontinuous pollution layers deposited on the insulator surface. Two zones are known to form: a clean (dry) zone and a polluted (wetted) zone. The influence of the length and position of the dry zone on the leakage current and the arc length are investigated. These were made on a plane experime…
Perfluoroheptadecan-9-one is a selective and mild catalyst for the epoxidation of a wide variety of alkenes with hydrogen peroxide; after the reaction the catalyst can be easily recovered and reused without noticable decomposition.
Hetrogenisation of H3PW12O40 and (nBu4N)4W10O32 with silica provides new photocatalytic systems able to oxygenate cyclohexane with O2 without causing the oxidative mineralization process which typically occur on the surface of the photosensitive semiconductor TiO2.
The ligands N-methyl-2,7-diazapyrenium (Medap+), N-(2-pyrimidyl)-4,4′-bipyridinium (PymQ+), N-methyl-4-[trans-2-(4-pyridyl)ethenyl]pyridinium (Mebpe+) and N-phenyl-4-[trans-2-(4-pyridyl)ethenyl]pyridinium (Phbpe+) have been used to prepare a series of complex salts trans-[RuII(NH3)4(LD)(LA)][PF6]3 [LD = NH3 and LA = M…
Room-temperature dechlorination process for polyvinyl chloride (PVC) has been developed. The process employs a mechanochemical (MC) treatment of PVC and CaO mixture followed by washing of mixture with water. MC reaction between PVC and CaO was induced by the treatments with a planetary mill and a new type of mill name…
The synthesis and optical properties of 4,4′-bis(dialkylaminophenylazo)-2,2′-bipyridine and 4,4′-bis(dialkylaminophenylimino)-2,2′-bipyridine ligands are described; the corresponding dipolar bipyridyl zinc dichloride complexes have been prepared and their second order nonlinear optical properties determined by electri…
The synthesis of CdS nanocrystals has been carried out by the thermolysis of cadmium dichloride with trioctylphosphine sulfide as the sulfur source, in tri-n-octylphosphine oxide at 250 °C. The material shows quantum size effects in the optical spectrum. The onset of absorption for CdS is at ≈480 nm (bulk CdS, 515 nm)…
Several different types of SiC fiber tows were coated with BN and composited using chemically vapor‐infiltrated SiC to form single‐tow minicomposites. The types of SiC fiber included Nicalon ™ , Hi‐Nicalon ™ , and the new Sylramic ™ polycrystalline SiC fiber. The interfacial shear stresses were determined from unload–…
The main properties of NiTi alloys are presented, discussed and compared with respect to those of stainless steels. Special regard is given to the use of NiTi alloy as orthodontic wires and endodontic instruments. The superelastic properties of orthodontic wires and endodontic files are measured as a function of the a…
Cobalt can be doped into the layered alkali manganese dioxides, M x Mn 1 − y Co y O 2 for M = K or Na , during the hydrothermal synthesis from the alkali permanganates. A single phase is obtained up to about 5 % mol cobalt. The cobalt doping is found to enhance the conductivity by two orders of magnitude relative to p…
The precipitation of CaCO3 during washing treatments can be reduced by polymeric additives. This process of incrustation inhibition could be described by modeling the effects upon crystal growth. Molecular dynamics calculations were used. Different conformations of the additives on the substrates developed during the…
The crystal structure of tyrosine aminotransferase (TAT) from the parasitic protozoan Trypanosoma cruzi, which belongs to the aminotransferase subfamily Igamma, has been determined at 2.5 A resolution with the R-value R = 15.1%. T. cruzi TAT shares less than 15% sequence identity with aminotransferases of subfamily Ia…
The aim of this work was to optimize protein entrapment in pure poly(epsilon-caprolactone) (PCL) microparticles (MP) using the (water-in-oil)-in water solvent evaporation technique and bovine serum albumin (BSA) as drug model. Therefore, the preparative variables such as polymer solvent, protein/polymer ratio, polymer…