Materials Literature
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Abstract The molecular relaxation processes and structure of isotactic polystyrene (iPS) films were investigated with real‐time dielectric spectroscopy and simultaneous wide‐ and small‐angle X‐ray scattering. The purpose of this work was to explore the restrictions imposed on molecular mobility in the vicinity of the…
In this paper, very systematic experimental data on the orientation dependence of the twinning stress in Cu–8 at.% Al single crystals are reported. A method, typical for ‘latent hardening experiments’, is employed to determine the critical stresses needed to activate twin systems in a dislocated crystal. Results show…
Abstract Acrylate and methacrylate monomers were obtained by reacting vernonia oil, a naturally epoxidized oil, with acrylic or methacrylic acid. The highest conversion (85–98%) of epoxy groups was obtained when the reaction was performed with an excess of the carboxylic acid at 100–120°C. The acrylate and methacrylat…
A survey is presented covering the results obtained by the present author and his co-workers during the last decade in studies on nickel single crystals and polycrystalline nickel cyclically deformed up to the saturation stage. Two main features of cyclic plasticity are the subject of discussion. The first part of the…
We measured the optical properties of mixed-valent vanadium oxide nanotubes to investigate the charge degrees of freedom in these novel materials. The electronic structure strongly resembles that of other bulk, low-dimensional, and molecular vanadates. The 1.2-eV band is assigned as a superposition of V 4+ d → d and V…
This paper reports for the first time on the fabrication of honeycomb-patterned cellulose films by casting water in oil emulsion of cellulose acetate onto a glass substrate and subsequent deacetylation treatment. The honeycomb pore size could be controlled from 1 to 100 microm under a saturated water vapor condition.…
Temperature dependence of zero-bias conductance of the vanadium (V)/multiwall carbon nanotube (MWNT)/V structure is studied. As temperature is reduced, the conductance decreases with a functional form consistent with a power law. For the first time, we find that the exponent depends significantly on gate voltage. This…
Abstract A new fluorinated diamine monomer, 2′,5′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐ p ‐terphenyl, was synthesized from the chloro‐displacement of 2‐chloro‐5‐nitrobenzotrifluoride with the potassium phenolate of 2,5‐diphenylhydroquinone, followed by hydrazine palladium‐catalyzed reduction. A series of trifluoromet…
The crossed-lamellar microarchitecture (microstructure) of the shell of Strombus gigas, the giant Queen conch native to Caribbean habitats, is the most common of the several shell microarchitectures known in the mollusk family. We have studied tissue regeneration in juvenile S. gigas conchs and compared the microstruc…
81Br Nuclear quadrupole resonance (NQR) measurement was performed in an S = 1/2 one-dimensional Heisenberg antiferromagnetic metal complex [NiBr(chxn)2]Br2 (chxn: 1R,2R-diaminocyclohexane), having a halogen-bridged MX chain structure -Br-Ni3+-Br-Ni3+-Br-. Two 81Br NQR signals were observed below 40 K, while a single s…
Nephrogenic fibrosing dermopathy (NFD) is a rare, recently described cutaneous fibrosing disorder that primarily affects patients with a history of renal disease [1]. Since the first report in 2000 by Cowper et al., about 100 cases of NFD have been described worldwide, and clusters have been observed in dialysis units…
Spider dragline silk is a semicrystalline protein polymer in which alanine-rich crystalline regions are connected by soft glycine-rich linkers that, in dry fibers are quiescent but become motionally active when plasticized by water. Using solid-state NMR to probe molecular motion and orientation of selectively 13 C-la…
We have studied the energetics and mobility of neutral hydrogen in alumina ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ using ab initio density-functional calculations. The mobility of hydrogen was studied in corundum $(\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3})$ as well as in liquid alumina. Using bot…
A novel carbon−sulfur (C 2 S) analogue of polyacene has been synthesized and characterized. The polymer is composed of a nondegenerate trans − cisoid polyacetylene backbone in which all hydrogen atoms are replaced with sulfur atoms to form thiophene rings that are fused into a linear cross-conjugated ladder-type struc…
ZnO nanowires were grown in gram quantities on graphite flakes (as collector) using the vapour transport and condensation approach. The yield, defined as the weight ratio of ZnO nanowires to the original graphite flakes, has been studied thoroughly by tuning the various growth parameters such as pressure and temperatu…
A comparative analysis of the polymorphic behavior of samples of isotactic polypropylene (iPP) prepared with heterogeneous Ziegler−Natta catalysts and with a single-center homogeneous metallocene catalyst is presented. Different samples of Ziegler−Natta iPP, prepared with MgCl 2 -supported catalysts modified by adding…
Abstract The water sorption characteristics of banana fiber–reinforced polyester composites were studied by immersion in distilled water at 28, 50, 70, and 90°C. The effect of hybridization with glass fiber and the chemical modification of the fiber on the water absorption properties of the prepared composites were al…
Dendrimers are well-defined and highly branched macromolecules. By utilizing their capsular architectures, dendrimers encapsulating various catalytically active species can be prepared, which often bring about unique catalysis. Treatment of the alkylated PPI dendrimer with 4-diphenylphosphinobenzoic acid and [PdCl(C3H…
The electronic and magnetic properties of ${\mathrm{S}\mathrm{r}\mathrm{F}\mathrm{e}\mathrm{O}}_{3\mathrm{\text{\ensuremath{-}}}\ensuremath{\delta}}$ single crystals with controlled oxygen content ($0\ensuremath{\le}\ensuremath{\delta}\ensuremath{\le}0.19$) have been studied systematically by susceptibility, transport…
Molecular recognition of gases is an emerging area of chemistry. Supramolecular chemistry helps us to understand how gases interact with biological molecules and offers delicate insights into the mechanisms of their physiological activity. Principles of molecular recognition have been used for gas sensing, and have pr…