Materials Literature
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Abstract Reversible oligomerization of distributions of molecules yields distributions of monomers, dimers, trimers, tetramers and higher‐order oligomers. The distributions can be functions of molecular weight, carbon number, or other variables that may be considered continuous. Rate expressions are formulated for the…
Electrochemical techniques were used to study the inhibition effects of molybdate (MoO42–), MoO42–+ nitrite (NO2–), MoO42– + tolyltriazole (TTA, CH3C6H4N3H), and MoO42– + NO2–+ TTA on the general and pitting/crevice corrosion of carbon (C) steel and some copper (Cu) alloys common to component cooling water systems (CC…
The structure of an activated quaternary complex of ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) from Synechococcus PCC6301 has been solved by molecular replacement. The protein crystallizes in an orthorhombic P2(1)2(1)2(1) unit cell with a complete L(8)S(8) complex consisting of 4608 residues (37 680 non…
Serine hydroxymethyltransferase has a conserved lysine residue (Lys-229) that forms the internal aldimine with pyridoxal 5'-phosphate. In other pyridoxal 5'-phosphate enzymes investigated so far, this conserved lysine residue also plays a catalytic role as a base that removes the alpha-proton from the amino acid subst…
Electron propagator calculations on the vertical and adiabatic ionization energies of BO2− yield structural information on ground and excited states of BO2. Analytical gradient techniques for BO2 geometry optimizations and renormalized self-energies for the evaluation of vertical ionization energies are employed. The…
A technique for measuring B-H curves of grain-oriented silicon steel along arbitrary directions has been developed. As the control of waveform is not necessary in this technique, it is possible to measure B-H curves up to high flux densities which are required for calculating flux distribution using the finite element…
Abstract A high‐temperature radical scavenger, 2,2‐diphenyl‐l‐picryl hydrazyl (DPPH), has been used to study the reaction mechanisms of polyacrylonitrile (PAN) on thermal treatment. The effect of DPPH on the cyclization reaction of PAN in both air and nitrogen, investigated by differential scanning calorimetry (DSC),…
The thermal behavior of flame retardant jute fabrics impregnated with a diam monium hydrogen phosphate (DAP) and urea (1:2) solution was studied using dif ferential scanning calorimetry ( DSC ) and thermogravimetric ( TG ) analysis in nitrogen and air atmospheres. Thermal degradation of flame retardant jute fabrics gr…
The sulfate‐reducing bacteria (SRB)‐enhanced corrosion of mild steel in the presence of 1.5 mg·l−1 dissolved oxygen (DO) in bulk liquid was investigated. The biofilm process analysis was combined with microelectrode measurements, electrochemical measurements, and surface analysis. In the early stages of biofilm accumu…
Point-defect energetics and diffusion mechanisms in graphite are investigated using a semi-empirical tight-binding-force model. Possible diffusion processes associated with point-defect (i.e., vacancies and interstitials) and nondefect (i.e., atomic exchange) mechanisms are analyzed. It is found that self-diffusion in…
Abstract Polycrystalline samples of perovskite‐structured BaCeO 3 and SrCeO 3 were studied by Raman scattering spectroscopy in the temperature range 77–983 K. Changes in the spectra of BaCeO 3 with temperature are explained in terms of a second‐order phase transition ( D 2 h → D 4 h ) at T 0 = 427 K. Analysis of the t…
Absorption and magnetic circular dichroism (MCD) spectra are reported for the metallophthalocyanine-N-isologs: magnesium-3,4-pyridinoporphrazine (MgPcN 4 (−2)), zinc-3,4-pyridinoporphyrazine (ZnPcN 4 (−2)), and zinc-3,4-pyridazinoporphyrazine (ZnPcN 8 (−2)). Band deconvolution calculations, which couple both the absor…
Solubilized silk fibroin (SF) in 0.1 M borate buffer (pH 9.4) was modified with 2-O-[methoxy(polyethylene glycol)]-4,6-dichloro-s-triazine (actPEG1) at 4 degrees C. The weight of the modified SF (PEG1-SF) was at least 3.2 times that of the starting material SF. Amino acid analysis of PEG1-SF suggested that the nucleop…
Abstract A scanning Raman spectrometer and an Nd: YAG laser operating at 1.06 μm were used to observe the surfaceenhanced Raman scattering (SERS) of pyridine in yellow silver colloids. Enhancement factors for the triangle ring breathing vibration mode at 1006 cm −1 and for the totally symmetric breathing mode at 1036…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharacterization of structure and morphology in two poly(ether-block-amide) copolymersGalen R. Hatfield, Yihong Guo, William E. Killinger, Ronald A. Andrejak, and Paul M. RoubicekCite this: Macromolecules 1993, 26, 24, 6350–6353Publication Date (Print):November 1, 1993Public…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHesperetin 7-O-glucoside and prunin in Citrus species (C. aurantium and C. paradisi). A study of their quantitative distribution in immature fruits and as immediate precursors of neohesperidin and naringin in Citrus aurantiumJulian. Castillo, Obdulio. Benavente, and Jose A.…
Four discotic liquid crystals (LCs) from the hexa-alkoxytriphenylene series (R = C n H2n + 1, n = 5, 7, 9, 11) classified as Dho phases were investigated with respect to their photoconducting properties. Under irradiation, all samples show photoconductivity within the mesophase, whereas in the isotropic phase the phot…
Abstract Studies of the morphology of extruded polymer blend systems have shown that it is feasible to produce a laminar structure of an ethylene vinyl‐alcohol copolymer (EVOH) dispersed phase in a polypropylene (PP) matrix phase. The laminar structure forms in the core of the extrudate when a slit die is incorporated…
A new low molar mass chiral organosiloxane mesogen and its racemic analogue have been synthesized and their mesomorphic and ferroelectric properties investigated. The chiral derivative, denoted A∗B, exhibits one tilted enantiotropic ferroelectric smectic C mesophase over a broad temperature range, with very high tilt…
For a given number of skeletal atoms, the π-electron count of an unsaturated heterocycle can be modified by the incorporation of heteroatoms from different periodic groups. Sulfur and nitrogen are particularly effective in this regard, as their high electronegativity can stabilize electron-rich π-systems. A variety of…