Materials Literature
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Nabiasite, ideally BaMn 9 [(V,As)O 4 ] 6 (OH) 2 , is a new mineral which occurs in rhodochrosite-, friedelite- and barite-bearing veinlets crosscutting Mn ores at the historic Pla de Labasse deposit near the Nabias hamlet, Central Pyrenees, France. These syn-genetic exhalative ores are embedded in Lower Carboniferous…
A helium-gas-pressure apparatus with optical-reflectivity detection tested with a spin-transition solid, Jelena Jeftic, Nieves Menéndez, AndréWack, Epiphane Codjovi, Jorge Linarès, Antoine Goujon, Gérard Hamel, Stefan Klotz, Gérard Syfosse, François Varret
The energy dissipation of Tb 3+ /Eu 3+ cations in both heterolanthanide multinuclear polyoxometalates, K 15 H 3 [Tb 1.4 Eu 1.6 (H 2 O) 3 (SbW 9 O 33 )(W 5 O 18 ) 3 ]·25.5H 2 O and Na 7 H 19 [Tb 4.3 Eu 1.7 O 2 (OH) 6 (H 2 O) 6 Al 2 (Nb 6 O 19 ) 5 ]·47H 2 O is studied by crystal structures, emission and excitation spect…
High molecular weight poly( l -glutamic acid) was chemically modified with a spiropyran reagent to give polypeptides containing 35 and 85 mol % spiropyran units in the side chains. To investigate the photochromic and conformational behavior in acid conditions, the polypeptides were dissolved in hexafluoro-2-propanol (…
A new diamine, bis[4-(4-aminophenoxy)phenyl]diphenylmethane (BAPDM ), bearing diphenylmethylene linkage was prepared starting from bis(4-hydroxyphenyl)diphenylmethane. The diamine was reacted with various aromatic dicarboxylic acids to obtain a series of new polyamides with moderate to high inherent viscosities of 0.6…
The reduction of chloroaurate and the incorporation of Au clusters in polyaniline, PANI, films have been investigated. The chloroaurate complex is generated at the electrode surface during Cl - doping of Au/PANI. FTIR and UV/vis data indicate that chloroaurate interacts with PANI and that its reduction to metallic Au…
The theoretical treatment of the evolution of a dislocation ensemble in a plastically deformed real crystal is discussed. Kinetic equations for the dislocation density are formulated which include elementary dislocation processes (source generation, immobilization, multiplication, annihilation, and diffusion) and on t…
Cathodic electrodeposition in an aqueous mixed solution of zinc nitrate and water-soluble tetrasulfonated metallophthalocyanines (TSPcMs), in which M = Zn(II) (TSPcZn), Al(III)[OH] (TSPcAl), or Si(IV)[OH] 2 (TSPcSi), resulted in a self-assembled growth of zinc oxide (ZnO) thin films whose surface is modified by TSPcMs…
Light absorption at the boundary of indirect-band-gap and direct-forbidden gap semiconductors is analyzed. It is found that the possibility of the electron momentum nonconservation at the interface leads to essential enhancement of absorption in porous and microcrystalline semiconductors. The effect is more pronounced…
We use empirical molecular dynamics technique to study the low-energy vibrations in a large 4096 atom model for pure amorphous silicon and a set of models with voids of different size based on it. Numerical vibrational eigenvalues and eigenvectors for our models are obtained by exact diagonalization of their dynamical…
I discuss the properties of electron states in amorphous Si based on large scale calculations with realistic several thousand atom models. A relatively simple model for the localized to extended (Anderson) transition is reviewed. Then, the effect of thermal disorder on localized electron states is considered. It is fo…
This research was undertaken to obtain new “BODIPY” dyes that fluoresce at relatively long wavelengths. The title compounds 1a − e were prepared via a divergent route involving Suzuki couplings of arylboronic acids to N - tert -butoxycarbonyl-4-bromopyrrole 2, condensation of the products with an acid chloride, and in…
Vinyl-functionalized MCM-41 samples were prepared by either a postsynthesis grafting (PSG) process or a direct co-condensation synthesis. The structures, stabilities, and reactivities of products from both methods were compared. The mesoscopic order of the hexagonal pore structure of vinyl-grafted MCM-41 (v-gr-MCM-41)…
The aromatic residues Phe-54, Phe-82, and Trp-116 in the hydrophobic substrate-binding pocket of Delta(5)-3-ketosteroid isomerase from Pseudomonas putida biotype B have been characterized in their roles in steroid binding and catalysis. Kinetic and equilibrium binding analyses were carried out for the mutant enzymes w…
Two series of polyether polyurethanes based on hydroquinone bis(β-hydroxyethy) ether (HQEE) or 1,4-butanediol (BDO) as a chain extender were prepared by a one-step bulk polymerization process. Their hydrogen bonding and morphological structure were studied by means of Fourier transform infrared spectroscopy (FTIR), di…
In this paper we study the static properties and the dynamical swelling behavior of thin spin-coated layers of natural polysaccharides on Si/SiO 2 substrates: the neutral and slightly branched dextran and the negatively charged, linear hyaluronic acid, by ellipsometric observation of the film swelling in a humidity-co…
Three novel bis(primary amine)iron(II) porphyrins [Fe(TPP)(RNH(2))(2)], where RNH(2) = 1-butylamine, benzylamine, and phenethylamine, have been synthesized and characterized by X-ray crystallography and IR, electronic, and Mössbauer spectroscopy. The compounds provide unprecedented structural data for the coordination…
Complexes of manganese(II)-containing aminoxyl radical substituted phosphine oxide ligands are reported. The compounds [(o-nitronyl nitroxide-phenyl)diphenylphosphine oxide]bis(hexafluoroacetylacetonato)manganese(II), 3, and bis{[(p-nitronyl nitroxide-phenyl) diphenylphosphine oxide]bis(hexafluoroacetylacetonato)manga…
Ovonyx, Inc. is developing a nonvolatile memory that is potentially denser, faster, and easier to make than Dynamic RAM. It relies on phase transitions induced by nanosecond heating and cooling of small region of the memory cell. Initial target markets are FLASH memory, Embedded memory, and DRAM.
We present a systematic study of how adsorption history affects the thickness, surface forces, and interfacial rheology of a model cationic polymer. The polymer was quaternized poly-4-vinylpyridine, QPVP (weight-average degree of polymerization n w = 325 and 98% quaternized with ethyl bromide). The main comparisons co…