Materials Literature
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Abstract The in vitro degradation behavior of the polyester/polyether copolymer based on polycaprolactone/poly(ethylene oxide)/polylactide (PCEL) significantly depends on the caproxyl (CL)/lactyl (LA) ratio for the same poly(ethylene oxide) (PEO) content. The PCEL copolymer with rich CL units shows the crystalline str…
Three novel metal polytellurides Rb(4)Hg(5)(Te(2))(2)(Te(3))(2)Te(3) (I), [Zn(en)(3)](4)In(16)(Te(2))(4)(Te(3))Te(22) (II), and K(2)Cu(2)(Te(2))(Te(3)) (III) have been prepared by solvothermal reactions in superheated ethylenediamine at 160 degrees C. Their crystal structures have been determined by single-crystal X-r…
We have developed an experimental setup to facilitate study of the surface reactions of single-crystal silicon with Fourier transform infrared (FTIR) spectroscopy in a variety of aqueous environments. Employing a short optical path length through the silicon sample allows access to the critical low-frequency region of…
Three new linear compounds of the type Co(3)(dpa)(4)X(2), where dpa is the anion of di(2-pyridyl)amine and X is NCS(-) (5), CN(-) (6), and N(CN)(2)(-) (7), have been prepared, and their structures and magnetic behavior have been studied. In all of them, including three different solvates of 5, the Co(3) chains are sym…
The problem of superspreading has recently attracted much attention both from the theoretical point of view and because of the practical use of the phenomenon. However, up to now there is no general agreement about the mechanism of the effect and on the necessary conditions for its realization, in particular regarding…
Sixteen crystal structures have been determined for the Co3(dpa)(4)Cl2 (1) molecule in the following five crystalline solvates: 1.0.85(C2H5)(2)O.0.15CH2Cl2 (at 120, 213, 296 K); 1.C(4)H(8)O (at 120, 295 K); 1.C(6)H(6) (at 170, 213, 260, 316 K); 1.C(6)H(12) (at 120, 213, 295 K); and 1.1.75C(7)H(8).0.5C(6)H(14) (at 90,…
We report the formation of monomeric and aggregated tetrakis( p -sulfonatophenyl)porphyrin encapsulated within an aluminosilicate mesostructure, specifically MCM-41, under different pH conditions. It was necessary to stabilize the synthesized MCM-41 through use of a silylation reagent, (aminopropyl)triethoxysilane, wh…
The effect of crystalline morphology on the hydrolytic degradation behavior of poly(butylene succinate) (PBS) in an alkaline solution was investigated by using scanning electron microscopy, gel permeation chromatography, and weight loss measurement. Morphological changes were induced on PBS samples by different therma…
The internal friction of oxide-ion conductor La 2 Mo 2 O 9 has been measured using a computer-controlled torsion pendulum. Two internal friction peaks were observed around 380 K and 833 K respectively at a vibration frequency of 1 Hz and a heating rate of 5 K min -1 . The lower-temperature peak is of relaxation type a…
A simple multiplicative scheme is proposed for the evaluation of the second-order nonlinear susceptibility of molecular crystals from the knowledge of the first hyperpolarizability of small molecular clusters. The principle of this new scheme is illustrated at the semiempirical AM1 level for 3-methyl-4-nitroaniline cr…
The present paper reports on the study of the disaccharides' dynamics in aqueous solutions and discusses the role of their interaction with water, which seems to be responsible for the protective action on biological membranes and tissues. In particular, using QENS (IRIS at ISIS, RAL, U.K.) we compared the quasielasti…
$o\ensuremath{-}{\mathrm{HoMnO}}_{3}$ crystallizes in the ${\mathrm{GdFeO}}_{3}$-type structure (Pbnm) with no crystal structure anomalies below 295 K and with the Mn-O-Mn angle as low as 144.1\ifmmode^\circ\else\textdegree\fi{}. The ${\mathrm{Mn}}^{3+}$ and ${\mathrm{Ho}}^{3+}$ magnetic moments are ordered below ${T}…
The electronic structure of ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3},$ which is a major constituent of the best thermoelectric material operating at room temperature, was calculated by using the first principles full-potential linearized-augmented-plane-wave method with spin-orbit interaction included by a second variation…
Lamellar dehydroxylation mechanisms are important in understanding highly reactive nanocrystal oxide formation as well as a variety of applied lamellar hydroxide reaction processes. These mechanisms have been observed for the first time via in situ nanoscale imaging for the prototype lamellar hydroxide: Mg(OH) 2 . Env…
The electrostatic charge and photoionization characteristics of 5-nm CdSe nanocrystals were directly observed with electrostatic force microscopy (EFM) in dry air at room temperature. Measurements were made on individual nanocrystals, as well as on those in self-assembled rafts. Nanocrystals are initially charge neutr…
The syntheses and structural and physical characterization of the compounds [Cu(bipy)(2)](2)[Mo(CN)(8)].5H(2)O. CH(3)OH (1) with bipy = 2,2'-bipyridine and M(II)(2)[Mo(IV)(CN)(8)].xH(2)O (2 with M = Cu, x = 7.5; 3 with M = Mn, x = 9.5) are presented. 1 crystallizes in the triclinic space group P1; (a = 11.3006(4) A, b…
The effects of free surfaces on the dynamic critical behavior of isotropic Heisenberg ferromagnets are studied via phenomenological scaling theory, field-theoretic renormalization group tools, and high-precision computer simulations. An appropriate semi-infinite extension of the stochastic model J is constructed, the…
Abstract Synergististic and catalytic effects in flame retardancy technology are reviewed. An attempt is reported to define and determine the synergistic effectivity (SE) and the catalytic effectivity (CAT‐EFF) of a number of systems operating according to the accepted mechanism. Synergistic effects in the halogen bas…
Bis(hexylmethyldithio-/diselenocarbamato)cadmium(II)/zinc(II) (M(E 2 CNMe n Hex) 2 [M = Zn, Cd; E = S, Se]) have been used as single-source precursors for the preparation of TOPO-capped CdS, CdSe, ZnS, and ZnSe nanoparticles. The precursors are stable for long periods of time and pyrolyse cleanly to give high yields o…
Rutherford backscattering and channeling measurements have been applied to study deep radiation damage and depth profile of implanted Au atoms in pure Cu and Cu-1 at. % Ni alloy single-crystal specimens, which were irradiated off axis at room temperature by 300 keV ${\mathrm{Au}}^{+}$ ions to a dose of $2\ifmmode\time…