Materials Literature
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Cobalt nitrosyl tetraphenylporphyrins CoT(p-X)PP(NO) (X = H, 1; OMe, 2; NO2, 3) substituted at the meso phenyl para position were prepared and the metal−NO interaction was probed using cyclic voltammetry and reflectance infrared spectroelectrochemistry. Electron-donating (OMe) and -withdrawing (NO2) groups were found…
(3-Hydroxybenzyl)hydrazine and methylhydrazine have been found to be potent slow-binding inhibitors of the pyridoxal 5-phosphate (PLP)-dependent enzyme gamma-aminobutyric acid aminotransferase (GABA-AT). Both compounds follow mechanism A (Morrison, J.F.; Walsh, C. T. Adv. Enzymol. 1988, 61, 201-301) which does not inv…
One of the major concerns in using Fiber Reinforced Composites (FRC) in applications that might be subjected to fire is their resistance to high temperature. Some of the fabrics used in FRC, such as carbon, are fire resistant. However, almost all the resins used cannot withstand temperatures higher than 200 degrees ce…
A layered ammonium zinc molybdate material was derived by a novel room-temperature chimie douce synthesis technique from a metastable mixed oxide prepared by calcination of a layered double hydroxide (LDH). The compound obtained, (NH 4 )HZn 2 (OH) 2 (MoO 4 ) 2, is highly crystalline and retains the rhombohedral symmet…
In the last few years there has been a considerable expansion in the application of Magnetic Force Microscopy (MFM). MFM images the stray field from the sample, offers excellent lateral resolution (/spl sim/10 nm) and requires minimal sample preparation. The interaction between the stray field from the sample and from…
In evaluating the performance of nonwoven fabrics, pore characteristics provide important information concerning fluid permeability, filtration and mechanical properties of the fabrics. This paper reports new approaches of measuring pore characteristics using image analysis. The image processing techniques for identif…
Simple tension tests were performed to investigate the load-elongation behavior of two geotextiles, a woven polyester and a nonwoven polypropylene, under monotonic and cyclic loading conditions. Creep tests under constant load were also performed in order to examine the time-dependent properties of both geotextiles. A…
Alkenyl succinic anhydride (ASA) is one of the reactive sizes used as cationic emulsions at wet-end of papermaking process. In order to make clear the mechanism of ASA sizing, structures of ASA components retained in handsheets were studied using model compounds and analytical techniques. The results of model experime…
Various poly(3-decylthiophene- co -3,3‘-dibutoxy-2,2‘-bithiophene)s and poly(4,4‘-didecyl-2,2‘-bithiophene- co -3,3‘-dibutoxy-2,2‘-bithiophene)s have been chemically prepared using iron trichloride as oxidizing agent in chloroform. These copolymers should combine the excellent electrical properties of alkoxy-substitut…
A novel layered titanium silicate JDF-L1 has been synthesized in an SiO2–TiO2–Na2O–H2O–H2O2 template system. It is found that the synthesis of JDF-L1 requires a relatively high alkalinity and an appropriate titanium content. The JDF-L1 samples were characterized by XRD, SEM, IR, DTA–TG and adsorption. DTA–TG studies,…
Shape memory polymers of polyurethane series have been developed. These polymers have the following features. (1) They can be molded easily similar to conventional plastics, (2) their shape recovery temperature can be set arbitrarily, and (3) they can be colored as required because they are transparent, making a wide…
Lys146 of rabbit aldolase A [D-fructose-1,6-bis(phosphate): D-glyceraldehyde-3-phosphate lyase, EC 4.1.2.13] was changed to arginine by site-directed mutagenesis. The kcat of the resulting mutant protein, K146R, was 500 times slower than wild-type in steady-state kinetic assays for both cleavage and condensation of fr…
A mixture of hard-sphere colloidal silica particles (radius 48 nm) and a nonadsorbing polymer (poly(dimethylsiloxane), radius of gyration 23 nm) is studied by means of static and dynamic light scattering near the binodal. The spinodal is determined from an extrapolation of the diffusion coefficient as measured in the…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTDiels−Alder Trapping of Photochemically Generated Dienes with a Bismaleimide: A New Approach to Polyimide SynthesisMary Ann B. Meador, Michael A. Meador, Lesley L. Williams, and Daniel A. ScheimanView Author Information NASA Lewis R…
A novel Ti−V−W−sepiolite catalyst for the selective catalytic reduction (SCR) of NO x with NH 3 was characterized by surface area and pore size distribution measurements, SEM, EDX, XRD, and FT-IR and FT-LR spectroscopy: the catalyst consists of TiO 2 particles impregnated with vanadia and tungsta and dispersed among t…
Atomistic models of two different fluorinated polybenzoxazoles, 6F-PBO and 3F-PBO, were used to simulate the amorphous structures of these polymers. Molecular mechanics and molecular dynamics techniques were utilized to relax the independent structures from an initial high-energy system. The relaxed model structures s…
Reduction of N-phenyl-meso-tetraphenylporphyrin with tosylhydrazine gives air-stable N-phenyl-meso-tetraphenylphlorin.
In order to discuss the dielectric performance of DC GIS, the flashover characteristics of gas-insulated bus were studied under conical- and disk-type spacers. The test involves the investigation on effect of electrification for charge to be accumulated in spacers and the effect of metallic particles. As the result, i…
Porphocyanines are tetrapyrrolic macrocycles containing two dipyrromethene units linked together by two C N−C bridges. The syntheses of 2,3,7,8,14,15,19,20-octaethylporphocyanine, 5,17-diphenylporphocyanine, 2,3,7,8-tetraethyl-17-phenylporphocyanine, and other meso -aryl and β-alkyl, including a tetra-β-propionate, de…
The phenomenon of bistable hysteresis in magnetic resonance of conduction electrons in solids is discussed, particularly the case of gallium oxide β-Ga 2 O 3 . This memory effect is a consequence of the dynamic polarization of nuclei by the Overhauser effect and manifests itself by a hysteresis of the ESR line provide…