Materials Literature
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Ag(I)/ZSM-5 catalyst was prepared and characterized spectroscopically in relation to its photocatalytic reactivity for the photodecomposition of nitric oxide. UV irradiation of the Ag(I)/ZSM-5 catalyst in the presence of NO leads to efficient catalytic conversion of NO into N 2, O 2, and other nitrogen oxides. Emissio…
The molecular structure of methylmalonyl CoA decarboxylase (MMCD), a newly defined member of the crotonase superfamily encoded by the Escherichia coli genome, has been solved by X-ray crystallographic analyses to a resolution of 1.85 A for the unliganded form and to a resolution of 2.7 A for a complex with an inert th…
A variety of porphyrin arrays connected together with different linkage were devised for possible applications to molecular optoelectronic devices such as wires, logic gates, and artificial light-harvesting arrays, etc. It has been relatively well established that the light signal transmission in these molecular assem…
The Escherichia coli genome encodes seven paralogues of the crotonase (enoyl CoA hydratase) superfamily. Four of these have unknown or uncertain functions; their existence was unknown prior to the completion of the E. coli genome sequencing project. The gene encoding one of these, YgfG, is located in a four-gene opero…
We simulate the propagation of a planar crack in a quasi-two dimensional fuse model, confining the crack between two horizontal plates. We investigate the effect on the roughness of microcrack nucleation ahead of the main crack and study the structure of the damage zone. The two dimensional geometry introduces a chara…
Concentrated colloidal solutions of well-dispersed YVO 4:Eu nanoparticles are synthesized by precipitation reactions at room temperature and stabilized by sodium hexametaphosphate. X-ray diffraction and electron microscopy characterizations show that the crystalline nanoparticles exhibit an ellipsoidal form with two c…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
The low-temperature annealing effect on electron field emission of tetrahedral amorphous carbon (ta-C) films was investigated. Ta-C films prepared by a filtered arc deposition technique were annealed at 400 °C for 60-120 min in a nitrogen atmosphere. The density and sp 3 content in as-grown film were 3.3 g cm -3 and ~…
Polycarbazole has been synthesized by electrochemistry. The carbazole monomer source consists either in carbazole in solution in the electrolyte or in carbazole deposited in thin film form onto the working electrode. The two families of polymers have been studied by infrared absorption, X-ray diffraction, thermal grav…
Delta(5)-3-Ketosteroid isomerase from Pseudomonas putida biotype B is one of the most proficient enzymes catalyzing an allylic isomerization reaction at rates comparable to the diffusion limit. The hydrogen-bond network (Asp99... Wat504...Tyr14...Tyr55...Tyr30) which links the two catalytic residues, Tyr14 and Asp99,…
Electron paramagnetic resonance (EPR) g tensors of 20 five- or six-coordinated d 1 metal porphyrins following the [M E(P)]−L structural motif (M = V(IV), Nb(IV), Cr(V), Mo(V); E = N, O, S, Se; P = porphyrin dianion; L = F -, Cl -, Br -, ClO 4 -, OH -, OCH 3 -, H 2 O, or not present) were computed using density functio…
The reaction between the propargyl radical (C 3 H 3 ) and NO has been investigated as a function of temperature (195−473 K) and pressure (3−100 Torr) by using color center laser infrared kinetic spectroscopy. At room temperature and below, the reaction rate was found to depend strongly on the helium buffer gas pressur…
The organized molecular structure of collagen is related to its dimensional stability. The dimensional stability of collagen arises from the interplay of various intermolecular forces such as covalent, hydrogen bonding, electrostatic interactions, hydrophobic interactions, London or van der Waals forces, and weak inte…
The grafting of hydroxy telechelic polybutadienes (HTPBD) by 2-mercaptoethanol to saturate 1,2-double bonds which enabled an increase of the OH functionality of HTPBD is presented. The functionalities of the virgin and grafted HTPBD were characterized both by 1H-NMR after silylation of the hydroxy end groups and the…
Perfluorinated polymer colloids with low refraction index are prepared via emulsion polymerization. The characterization is done using small-angle X-ray scattering and dynamic light scattering. The independently obtained particle size distributions are in remarkable mutual agreement and give evidence for the monodispe…
In an effort to design cyclic anhydride copolymers that have biodegradable characteristics and are derived from renewable resources, the copolymerization of itaconic anhydride and methacrylate-terminated poly-(L-lactic acid) (PLLA) was studied. Polymers with anhydride concentrations from 85 to 15 mol% have been synthe…
Sodium-covered silica films formed on silicon substrates are examined by X-ray photoemission spectroscopy (XPS) and X-ray absorption fine structure spectroscopy (EXAFS) in ultrahigh vacuum conditions. The presence of sodium, which diffuses within the silica matrix at 300 K results in a shift of the O 1s core level tow…
Two grades of nuclear graphite, an isotropic graphite (GCMB) and an anisotropic graphite (PGA), were thermally oxidized to high weight losses. Average values of the coefficient of thermal expansion (CTE) in the temperature range 20-600 °C for GCMB and PGA in the parallel direction were unaffected by thermal oxidation…
A microcalorimetric method is proposed to determine the contact angle of a nonwetting liquid within a mesoporous solid. It is based on the simultaneous measurement of the heat and work of wetting, as the pressure is raised. The method simply requires a previous determination of the surface area to be wetted. It allows…
Hydroxy telechelic poly( l -lactide)s of different molecular weight have been synthesized by controlled ring-opening polymerization using cyclic tin alkoxides. NMR analysis showed that the propagation proceeded through an insertion mechanism. No free hydroxyl or carboxyl end groups were detected in the polymerization…