Materials Literature
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The equations of state at room temperature as well as the energies of crystal structures up to pressures exceeding 100 GPa are calculated for Na and K . It is shown that the allowance for generalized gradient corrections (GGA) in the density functional method provides a precision description of the equation of state f…
We have studied polariton spin dynamics in a GaAs/AlGaAs microcavity by means of polarization- and time-resolved photoluminescence spectroscopy as a function of excitation density and normal mode splitting. The experiments reveal a novel behavior of the degree of polarization of the emission, namely the existence of a…
[formula: see text] A novel, metal-free oxidation system for the catalytic synthesis of aldehydes and ketones--TEMPO/Oxone--has been developed. An optimized reaction protocol proved especially successful for the synthesis of ketones. Additionally, the influence of quarternary ammonium salts on the catalysis was studie…
The redox behavior of Cu/ZSM-5 zeolites prepared by ion exchange from Cu 2+ aqueous solutions has been followed by a variety of spectroscopic techniques to provide a thorough picture of the so-called “self-reduction” of cupric ions, which occurs upon dehydration of the hydrated system at various temperatures, and of t…
We have examined the properties of polypyrrole (PPy) as a model electroactive membrane which can simultaneously serve as a medium sensing, and bioactive molecule releasing, material using optical spectroscopic, potentiometric, and conductometric methods. In particular, PPy membranes can sense hydrazine in aqueous solu…
Descriptions of phase separation in condensed matter have so far been classified into a solid model (model B) and a fluid model (model H). In the former the diffusion is the only transport process, while in the latter material can be transported by both diffusion and hydrodynamic flow. It has recently been found that…
The neutral trinuclear carboxylato-bridged iron(II) complex [Fe3(O2CCH3)3(BPG)3] can, after minor structural rearrangement, bind a fourth iron(II) ion, forming the tetranuclear complex [Fe4(O2CCH3)3(BPG)3](ClO4)2. The triiron(II) complex can thus be considered as a metallacrown host for the fourth iron(II) ion.
Static and dynamic light-scattering experiments on a nematic side-group polymer are described. Using two different scattering geometries, the depolarized scattering due to thermally excited fluctuations of the nematic director was analyzed. The relaxation rates and strengths show the q dependence known from low molar…
To investigate the linkage between enzyme conformation and catalysis, we have determined the effects of temperature on catalytic properties of the tryptophan synthase alpha(2)beta(2) complex and beta(2) subunit in the absence or presence of different monovalent cations (Cs(+), Na(+), and GuH(+)) and of an allosteric l…
Materials belonging to the Ti 1 - x Ru x O 2 system, where 0 ≤ x ≤ 1 (mol), have been synthesized by a polymeric sol−gel route and calcined in air at 1300 °C by rapid firing. The crystalline evolution of the prepared materials has been investigated, as a function of temperature, by means of differential thermal analys…
Blends of bacterial poly(hydroxybutyrate) (PHB) with poly(hydroxyoctanoate) (PHO) were prepared by co-dissolving the two polyesters in chloroform and casting the mixture. To probe the question of blend miscibility, scanning electron microscopy (SEM) observations and differential scanning calorimetry (DSC) spectra were…
Ag(I)/ZSM-5 catalyst was prepared and characterized spectroscopically in relation to its photocatalytic reactivity for the photodecomposition of nitric oxide. UV irradiation of the Ag(I)/ZSM-5 catalyst in the presence of NO leads to efficient catalytic conversion of NO into N 2, O 2, and other nitrogen oxides. Emissio…
The molecular structure of methylmalonyl CoA decarboxylase (MMCD), a newly defined member of the crotonase superfamily encoded by the Escherichia coli genome, has been solved by X-ray crystallographic analyses to a resolution of 1.85 A for the unliganded form and to a resolution of 2.7 A for a complex with an inert th…
A variety of porphyrin arrays connected together with different linkage were devised for possible applications to molecular optoelectronic devices such as wires, logic gates, and artificial light-harvesting arrays, etc. It has been relatively well established that the light signal transmission in these molecular assem…
The Escherichia coli genome encodes seven paralogues of the crotonase (enoyl CoA hydratase) superfamily. Four of these have unknown or uncertain functions; their existence was unknown prior to the completion of the E. coli genome sequencing project. The gene encoding one of these, YgfG, is located in a four-gene opero…
We simulate the propagation of a planar crack in a quasi-two dimensional fuse model, confining the crack between two horizontal plates. We investigate the effect on the roughness of microcrack nucleation ahead of the main crack and study the structure of the damage zone. The two dimensional geometry introduces a chara…
Concentrated colloidal solutions of well-dispersed YVO 4:Eu nanoparticles are synthesized by precipitation reactions at room temperature and stabilized by sodium hexametaphosphate. X-ray diffraction and electron microscopy characterizations show that the crystalline nanoparticles exhibit an ellipsoidal form with two c…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
The low-temperature annealing effect on electron field emission of tetrahedral amorphous carbon (ta-C) films was investigated. Ta-C films prepared by a filtered arc deposition technique were annealed at 400 °C for 60-120 min in a nitrogen atmosphere. The density and sp 3 content in as-grown film were 3.3 g cm -3 and ~…
Polycarbazole has been synthesized by electrochemistry. The carbazole monomer source consists either in carbazole in solution in the electrolyte or in carbazole deposited in thin film form onto the working electrode. The two families of polymers have been studied by infrared absorption, X-ray diffraction, thermal grav…