Materials Literature
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Abstract Poly(N 1 ,N 3 ‐dimethylbenzimidazolium) (PDMBI) salt and poly(N 1 ‐methylbenzimidazole) (PMMBI) were synthesized by methylation of commercial polybenzimidazole [poly‐2,2′‐( m ‐phenylene)‐5,5′‐bibenzimidazole (PBI)]. First, the N‐lithium salt of polybenzimidazole was formed by treating polybenzimidazole soluti…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, characterization, stability, aqueous surface activity, and aqueous solution aggregation of the novel, cationic siloxane surfactants (Me3SiO)2Si(Me)-(CH2)3+NMe2(CH2)2OR X- (R = hydrogen, acetyl, N-phenylcarbamyl; X = chloride, bromide, iodide, nitrate, methyl sulfa…
The crystal structure of synthetic tolbachite, CuCl 2 , has been refined by the Rietveld method using an X-ray powder diffractometer modified for atmospheric control. The structure is monoclinic, space group C2/m, a=6.9038, b=3.2995, c=6.824A, β=122.197°, Z=2, with Cu 2+ at (000), and Cl - at [0.5048,0,0.2294]. The st…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnionic homopolymerization and block copolymerization of 4-vinylpyridine and its investigation by high-temperature size-exclusion chromatography in N-methyl-2-pyrrolidinoneSunil K. Varshney, Xing Fu Zhong, and Adi EisenbergCite this: Macromolecules 1993, 26, 4, 701–706Public…
We present ab initio calculations of x-ray-absorption fine structure for the Re ${\mathit{L}}_{3}$ and ${\mathit{L}}_{1}$ edges in crystalline ${\mathrm{ReO}}_{3}$ based on an exact curved-wave multiple-scattering approach. Good agreement between theoretical and experimental data has been found for both edges. We show…
Proteins exposed to ionizing radiation suffer both reversible and irreversible effects. Reversible effects are defined as those which disappear in a short period of time after the removal of the radiation field and without further treatment of the sample. Irreversible effects are those which cause a permanent alterati…
The Hall-Petch relation, developed originally for single-phase alloys, has been extended to alloys containing two ductile phases. The extended Hall-Petch relation can separate the contributions from the different kinds of boundary to the overall efficiency of grain and phase boundaries as obstacles to dislocation moti…
Abstract Surface Raman spectral studies of triphenylmethane dyes on colloidal silver were carried out. An assessment of the surface and solution spectra led to the conclusion that the dye molecules are most likely lying parallel to the surface of the sol and adopting C 3 symmetry. The major vibrational changes suggest…
A high‐strength machinable glass‐ceramic was prepared by controlling the crystallization of ZrO 2 ‐containing Ca 0.43 K 0.14 Mg 3 (Si 3 AlO 10 )F 2 glass. A unique microstructure of the glass‐ceramic was observed, using transmission electron microscopy (TEM): zirconia particles of nanometer size, 20–50 nm, were embedd…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSimulated annealing on free energy surfaces by a combined molecular dynamics and Monte Carlo approachBruce TidorCite this: J. Phys. Chem. 1993, 97, 5, 1069–1073Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPalladium-catalyzed reaction of 5-methylene-1,3-dioxolan-2-ones. A new access to and reactivity of oxatrimethylenemethane-palladiumKouichi Ohe, Hideki Matsuda, Toshihisa Ishihara, Sensuke Ogoshi, Naoto Chatani, and Shinji MuraiCite this: J. Org. Chem. 1993, 58, 5, 1173–1177P…
A series of N, N-di-n-alkyl-N,N-dimethylammonium bromides was synthesized and characterized. Its thermotropic liquid-crystalline behaviour was studied by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. A novel smectic mesophase was thus identified, in which the lateral packing o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFoam breakdown by hydrophobic particles and nonpolar oilRobert Aveyard, Philip Cooper, Paul D. I. Fletcher, and Christine E. RutherfordCite this: Langmuir 1993, 9, 2, 604–613Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inis…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface chemistry of boron oxidation. 2. The reactions of boron oxides B2O2 and B2O3 with boron films grown on tantalum(110)Yajun Wang and Michael TrenaryCite this: Chem. Mater. 1993, 5, 2, 199–205Publication Date (Print):February 1, 1993Publication History Published online1…
Composite films of carbon and SiO 2 were prepared by a rf cosputtering technique and their photoluminescence and absorption spectra were measured. A strong and broad photoluminescence peak located around 2.2 eV (visible to the naked eye) was observed for the samples with relatively low carbon concentrations. The blue…
Light-scattering and transmission properties of aligned nematic droplets dispersed in a solid polymer are studied. Theoretical evaluations of the differential and total cross sections are performed in the anomalous diffraction approximation. The corresponding attenuation coefficients are calculated in a single scatter…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular alignment of polymer liquid crystals in shear flows. 1. Spectrographic birefringence technique, steady-state orientation, and normal stress behavior in poly(benzyl glutamate) solutionsK. Hongladarom, W. R. Burghardt, S. G. Baek, S. Cementwala, and J. J. MagdaCite t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDynamic mechanical relaxations of ethylene ionomersHitoshi Tachino, Hisaaki Hara, Eisaku Hirasawa, Shoichi Kutsumizu, Kenji Tadano, and Shinichi YanoCite this: Macromolecules 1993, 26, 4, 752–757Publication Date (Print):February 1, 1993Publication History Published online1 M…
The flow of a periodic suspension of two-dimensional viscous drops between two parallel plane walls is considered, and a framework for performing dynamic simulations with suspensions of increasingly complex structure is developed. The computations are based on an improved implementation of the boundary integral method…
The in vitro hydrolytic degradation of 2-0 size PDS monofilament suture was studied for the purpose of revealing its morphologic structure and degradation mechanism. The sutures were immersed in phosphate buffer of pH 7.44 for up to 120 days at 37 degrees C. These hydrolyzed sutures were examined by the changes in ten…