Materials Literature
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A new method for the synthesis of inroganic—organic composites with promising properties is the incorporation of polyoxometalates into well-ordered organic films by the Langmuir–Blodgett (LB) method. The structure of such an LB film is depicted schematically on the right.
The magnetic structure of antiferromagnetically ordered phases of quasi-one-dimensional organic conductors is studied theoretically at absolute zero based on the mean field approximation to the quarter-filled band with on-site and nearest-neighbor Coulomb interaction. The differences in magnetic properties between the…
Femtosecond nonlinear transmission techniques are applied to study mechanisms for optical nonlinearities and ultrafast carrier dynamics in CdS nanocrystals (NC's). The obtained data indicate the change in a dominant hole relaxation channel at high pump levels where nonlinear recombination effects start to play a signi…
Using natural rubber latex as the sole source of carbon and energy 50 rubber-degrading bacteria were isolated. Out of those 50 isolates, 33 were identified as Streptomyces species and 8 as Micromonospora species. Screening of 1220 bacteria obtained from different culture collections revealed 46 additional rubber-degra…
Extrinsic levels, formation energies, and relaxation geometries are calculated ab initio for oxygen vacancies in alpha-quartz SiO2. The vacancy is found to be thermodynamically stable in the charge states Q=+3, Q=0, Q=--2, and Q=-3. The charged states are stabilized by large and asymmetric distortions near the vacancy…
Component of photoexcited states with large spatial extent is investigated for optical absorption spectra of the electroluminescent conjugated polymers by using the intermediate exciton theory. We calculate the ratio of oscillator strengths due to long-range excitons with respect to sum of all the oscillator strengths…
This monograph describes the theory and practice of electron spectrometry using synchrotron radiation. The book is in three parts. After a short review of background theory, neon is used to elucidate the principles of the photoelectron and Auger spectra. The second part of the book looks at experimental aspects, inclu…
A methodology is introduced for predicting the effective thermal conductivity of arbitrary particulate composites with interfacial thermal resistance in terms of an effective medium approach combined with the essential concept of Kapitza thermal contact resistance. Results of the present model are compared to existing…
We discuss a generalization of the surface reconstruction arguments for the structure of intermediate size Si clusters, which leads to model geometries for the sizes 33, 39 (two isomers), 45 (two isomers), 49 (two isomers), 57 and 61 (two isomers). The common feature in all these models is a structure that closely res…
Nb-substituting Fe impurity in KNbO3 is studied in first-principles supercell calculations by the linear muffin-tin orbital method. Possible ways to account for the impurity charge compensation are discussed. Calculations are done in the local density approximation (LDA) and, for better description of Coulomb correlat…
We report the experimental results of impurity contamination and laser-induced damage investigations on rapidly grown potassium dihydrogen phosphate (KDP) crystals. Using absorption spectroscopy and chemical analysis, we determined the impurity distribution in the different growing sectors of KDP single crystals. The…
The three-dimensional structure of glutamate-1-semialdehyde aminomutase (EC 5.4.3.8), an alpha2-dimeric enzyme from Synechococcus, has been determined by x-ray crystallography using heavy atom derivative phasing. The structure, refined at 2.4-A resolution to an R-factor of 18.7% and good stereochemistry, explains many…
Recently, the target function for crystallographic refinement has been improved through a maximum likelihood analysis, which makes proper allowance for the effects of data quality, model errors, and incompleteness. The maximum likelihood target reduces the significance of false local minima during the refinement proce…
In order to arrive at ultimately accurate results available with the LMTO method in the local density approximation, the stability of full-potential LMTO predictions for off-center displacements in KNbO3, as depending on the choice of basis and expansion cutoffs, has been thoroughly investigated. With the calculation…
Graphs of second harmonic generation coefficients and electro-optic coefficients (measured by ellipsometry, attenuated total reflection, and two-slit interference modulation) as a function of chromophore number density (chromophore loading) are experimentally observed to exhibit maxima for polymers containing chromoph…
The frequency dependence of the AC electrical conductivity of different compositions of bismuth cuprate glasses has been presented in the temperature range 80 - 400 K. The conductivity data have been analysed in terms of different theoretical models to determine the possible conduction mechanism. Analysis of the condu…
The effect on the thermal and dielectric properties of incorporating benzene rings in hydrogenated amorphous carbon (a-C:H) films was investigated. The benzene rings were introduced into a-C:H films by using plasma-enhanced chemical vapor deposition and aromatic source compounds. The a-C:H film that contained benzene…
Diamondlike carbon (DLC) thin films have been prepared by chemical vapor deposition assisted by electron cyclotron resonance plasma at low pressure with radio frequency (rf) power applied to the substrate. The microstructure studies by transmission electron microscopy and electron energy loss spectroscopy show the exi…
We present the first experimental evidence for ``disorder broadening'' of core level x-ray photoemission line shapes in alloys. The broadening is attributed to variations in electrostatic potential. A model in which the charge on a site is assumed to be proportional to its number of unlike neighbors has recently been…
We propose a novel method of measuring the cholesteric pitch of a liquid crystal (LC) in a circularly aligned configuration. The LC cell is made with one homogeneously rubbed surface and one circularly rubbed surface so that it produces a disclination line passing through the singularity created by the circular rubbin…