Materials Literature
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Lipophilic and hydrophilic dendra which are terminated with long alkyl chains and oligomeric poly(ethylene glycol) moieties, respectively, were synthesized, and these dendron species were used to functionalize single-wall (SWNT) and multiple-wall (MWNT) carbon nanotubes via amidation and esterification reactions. The…
Goniophotometry has enabled measurement of the angle that the surface of the cuticle (the scales) of a human hair fiber makes with the axis of the hair shaft. This measuring technique has been used to obtain the change of this scale angle with extension of a hair fiber under fixed conditions of temperature and relativ…
Abstract The effect of the solvent composition on the elasticity of strong and weak cation‐ and anion‐exchange resin beads was studied. Poly(styrene‐ co ‐divinylbenzene) resins containing sulfonic acid or quaternary ammonium groups and an acrylic acid resin crosslinked with divinylbenzene were immersed in water, NaCl…
We have conducted temperature and frequency dependent transport measurements in amorphous ${\mathrm{Nb}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}$ samples in the insulating regime. We find a temperature dependent dc conductivity consistent with variable range hopping in a Coulomb glass. The frequency dependent response in…
A comprehensive photophysical study of protonated species of (tetra-tert-butylphthalocyaninato)zinc (tBu4ZnPcHnn+, n = 0–4) is reported. Singlet and triplet state properties have been measured and discussed with reference to the effects of protonation which occur at the azomethine bridging nitrogens of the phthalocyan…
The adsorption of polymer dispersants of the polyisobutenylsuccinimide series has been studied at the solid/xylene interface. Carbon black was studied as a model solid. Adsorption isotherms were determined, the enthalpy of adsorption was measured by calorimetry, and the thickness of the adsorbed layer was obtained fro…
Enzymes of the glyoxylate-bypass pathway are potential targets for the control of many human diseases caused by such pathogens as Mycobacteria and Leishmania. Isocitrate lyase catalyses the first committed step in this pathway and the structure of this tetrameric enzyme from Escherichia coli has been determined at 2.1…
Abstract 4‐{ n ‐[4‐(4‐Nitrophenylazo)phenyloxy]alkyl}aminobenzene sulfonic acid (C n ‐ABSA, where n = 2, 4, 6, 8, or 10) as a novel dopant for conducting polymers of polyaniline (PANI) was designed and synthesized. The molecular structure of C n ‐ABSA was characterized with 1 H NMR, Fourier transform infrared, and sec…
The evolution of the dielectric α relaxation and ionic conductivity with time t r during polymerization at 60 °C of mixtures of the diepoxide DGEBA, the diamine PACM, and the diluent Decalin (DEC) or di- n -butyl phthalate (DBP) has been studied using real-time dielectric relaxation spectroscopy (DRS). Data are presen…
Reaction of organocobalt(III) porphyrins with a cobalt(II) complex of a distinguishable porphyrin or tetrapyrrole resulted in the reversible exchange of the organic axial ligand. The exchange reaction was facile in such solvents as benzene, toluene, dichloromethane, chloroform, and pyridine; was unaffected by total ex…
The previously unknown crystal structure of the C(1) subunit of the carotenoid-binding protein alpha-crustacyanin has been determined using the anomalous scattering available at 1.77 A wavelength to determine the partial structure of the S atoms intrinsic to the native protein. The resulting 'heavy-atom' phases, in co…
The synthesis of poly(vinyl hydroquinone), PVHQ, via stable free radical polymerization (SFRP) to give a low-dispersity (1.5) material is described. The electrochemical properties of the resulting material deposited as films onto glassy carbon electrodes have been investigated by cyclic voltammetry. In aqueous acetic…
A first-principles molecular dynamics study of glassy ${\mathrm{As}}_{2}{\mathrm{Se}}_{3}$ and ${\mathrm{As}}_{4}{\mathrm{Se}}_{4}$ is presented. We focus on the differences in local structure between these glasses and identify the structural elements of ${\mathrm{As}}_{4}{\mathrm{Se}}_{4}$ and present a model of the…
A series of π-conjugated rodlike polymers, poly(2,5-dialkyl p -phenyleneethynylene)s, PPE's, were synthesized with alkyl groups of n -butyl ( 4a ), n -octyl ( 4b ), n -tetradecyl ( 4c ), 2-ethylhexyl ( 4d ), and 2-cyclohexylethyl ( 4e ). Polymers with linear alkyl side groups ( 4a, 4b, and 4c ) formed gels in toluene…
The coordination environments of Ge and As atoms in ${\mathrm{Ge}}_{x}{\mathrm{As}}_{y}{\mathrm{S}}_{1\ensuremath{-}x\ensuremath{-}y}$ glasses with $x:y=1:2,$ 1:1, and 2.5:1 and with wide-ranging S contents have been studied with Ge and As K-edge x-ray absorption fine structure spectroscopy. The coordination numbers o…
Using ab initio pseudopotential plane wave method and generalized gradient approximation for the exchange and correlation energy, we report the finding of high spin ground state of ${\mathrm{Al}}_{12}\mathrm{Cu}$ cluster in accordance with the Hund's rule of maximum spin at half-filling. It has perfect icosahedral sym…
Abstract The rheological properties, morphology, and oil resistance in natural rubber and nitrile‐butadiene rubber (NR/NBR) blends are investigated as functions of the blending conditions. It is found that the Mooney viscosity of the blends depends more strongly on the blending time than the rotor speed. The size of t…
The polarization modulation infrared reflection−absorption spectroscopy (PM-IRRAS) technique has been used in situ to determine the orientation and molecular structure of an equimolar mixture of poly( l -lactide) (PLLA) and poly( d -lactide) (PDLA) spread at the air−water interface. The characteristics of the compress…
Plasma reforming and coupling of methane with carbon dioxide using a point-to-point type of reactor have been invested. A feed mixture of CH 4 and CO 2 could be converted mainly to CO, H 2, and C 2 H 2 at atmospheric pressure and without external heating except plasma heating. Under a condition of 200 mL/min of CH 4 a…
Nanocrystalline powders of ceria doped with 20 at. % of various rare-earth cations (Ce 0.8 RE 0.2 O 1.9, RE = La, Nd, Sm, Gd, Dy, Y, Ho, Er, and Yb) have been synthesized via coprecipitation using ammonium carbonate as the precipitant. The precursors and the resultant oxide powders were characterized by chemical analy…