Materials Literature
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A new direct-methods procedure has been devised which consists of phase refinement via the minimal function, R(phi), alternated with Fourier summation and real space filtering. All phases are initially assigned values by computing structure factors for a randomly positioned set of atoms. These phases are then refined…
Currently, there are a large variety of degradable polymers available for use in surgery, which are generally based on blends and copolymers of poly(L-lactide) (PLLA) and poly(L-glycolide) (PGA). The major demand for these materials is for suturing of wounds, but the materials are also being developed for use in ortho…
The (R4N)2[Ni(tdas)2] complexes (tdas2–= 1,2,5-thiadiazole-3,4-dithiolate and R = Bu, Et) are prepared and characterized by X-ray crystallography, which reveals differences in their structure dependant on the size of the R4N cation.
Partial discharge measurement is an important means of assessing the condition and integrity of insulation systems in high voltage power apparatus. Commercially available partial discharge detectors display them as patterns by an elliptic time base. Over the years, experts have been interpreting and recognising the na…
The synthesis and characterization of side-chain liquid-crystalline polysiloxanes based on 4′-cyanobiphenyl-4-yl 2-(2-allyloxyethoxy)-4-(4-methoxybenzyloxy)benzoate (11-1), 4′-cyanobiphenyl-4-yl 2-[2-(2-allyloxyethoxy) ethoxy]-4-(4-methoxybenzyloxy) benzoate (11-2) and 4′-cyanobiphenyl-4-yl 2-{2-[2-(2-allyloxyethoxy)e…
The effect of additives on carbothermal reduction-nitridation was investigated for the preparation of AlN powders from the Al2O3-C-N2 system. According to the role of additives in nitridation, they were divided into three categories: “promote”, “have no effect” and “disturb”. In particular, CaF2 was an excellent nitri…
The reaction of the hydrated β-diketonate complexes [Ln(tmhd)3(H2O)] with triglyme (2,5,8,11-tetraoxadodecane, L1) in hexane yielded the eight-coordinate triglyme-bridged dimeric complexes, [{Ln(tmhd)3}2L1](Ln = Eu 1 or Tb 2; tmhd = ButCOCHCOBut). In contrast, the reaction of [La(tmhd)3(H2O)] with tetraglyme, (2,5,8,1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymer brush in contact with a mixture of solventsJ. F. MarkoCite this: Macromolecules 1993, 26, 2, 313–319Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 January 1993https://pubs.acs.org/doi/10.1021/ma00054a010https…
All articles of this category Syntheses of two novel classes of water soluble phthalocyanines substituted with propionic acid or O-ethyl, methyl-phosphonic acid groups are described. These compounds have applications in the field of photodynamic inactivation of cancer cells and viruses.
The synthesis and characterization of cyclic main chain liquid-crystalline oligomers based on 1-(4-hydroxy-4′-biphenyl)-2-(4-hydroxyphenyl)butane (TPB) with 1,7-dibromoheptane (TPB-7(c)] are described. These oligomers were synthesized by the phase transfer catalysed polyetherification of TPB with 1,7-dibromoheptane un…
Shear-induced homogenization of semidilute solutions of polybutadiene (PB) and polystyrene (PS) with dioctylphthalate as a solvent was studied as a function of temperature T, polymer compositions at a fixed total polymer concentration of 3.3 wt%. The drop of homogenization temperature ΔTc(S) as measured in the increas…
The reaction of KCa[Cr(C2O2S2)3]·6H2O (C2O2S2= dithiooxalate) and [NiL][ClO4]2(L = racemic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) in the 1:3 molar ratio gave a chromium(III)trinickel(II) complex [Cr(C2O2S2)3(NiL)3][ClO4]3. It crystallizes with two dimethylformamide and two PriOH molecules in the…
Abstract The mechanically induced changes in structure and magnetic properties of zinc ferrite were investigated by using the Rietveld analysis and Mössbauer spectroscopy. The formation of the spin arrangement in mechanically activated zinc ferrite is connected with a redistribution of the cations in the close‐packed…
Electrical conductivity and the Seebeck coefficient of compositions in the system Y[sub 1-y]Ca[sub y]MnO[sub 3] and La[sub 1-y]Ca[sub y]MnO[sub 3] were studied to determine the mechanism of electrical transport and defect structure. Electrical conduction appeared to occur via a small polaron hopping mechanism for comp…
Recent versions of PSPICE, a personal computer implementation of the SPICE circuit simulation computer software program, have the capability of simulating the hysteresis loops of magnetic materials. In order to model the hysteresis loop of a particular manufacturer's magnetic core material, the values of five paramete…
The dispersive component of the surface free energy, the nondispersive interaction, with polar liquids were determined for cellulose, cellulose acetate and cellulose grafted with alkyl ketene dimer (AKD). and were calculated in the dry state as well as the fully hydrated state by the two liquid contact angle method. w…
The complexes [MnII(L2)2]l2·2MeOH 1 and [CuIII(L1)]2 have been synthesized by a template-like reaction between S-methylisothiosemicarbazide and pentane-2,4-dione, with MnCl2 and Cu2(MeCO2)4·2H2O, respectively, in MeOH by air oxidation; both species have been characterized by X-ray crystallography.
Abstract The influence of thermoplastic polyurethane (TPU) elastomer on the rigidity of polyacetal (polyoxymethylene, POM) was studied by determining heat deflection temperature (HDT). The higher the content of TPU in the POM/TPU blend, the lower the HDT of the blend, as would be expected. A comparative study of the r…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSide-chain liquid crystalline poly(N-maleimides). 5. Dielectric relaxation behavior of liquid crystalline side-chain and amorphous poly(N-maleimides). A comparative structural studyF. Romero Colomer, J. M. Meseguer Duenas, J. L. Gomez Ribelles, J. M. Barrales-Rienda, and J.…
New intercalation compounds, M1–xPS3(G)2x(H2O)y(M = Mn, Cd) have been synthesized, where G denotes the 4-[4-(dimethylamino)-α-styryl]-1-methylpyridinium cationic chromophore. The non-linear optical properties of these materials were studied by the Kurtz powder technique. Second-harmonic generation has been evidenced,…