bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical properties of vacuum‐evaporated ZnTe films
Authors: Patel N. G. 
Published: January 2007

AbstractZnTe thin films were grown on glass substrates using vacuum evaporation technique. A cylindrical furnace is designed for substrate heating, which improve the crystallite size and stoichiometry over wide substrate temperature range. The variation of electrical resistivity and photosensitivity are explained on the basis of stoichiometric composition and improvement in the crystallite size of ZnTe films deposited at different substrate temperatures. The effect of films thickness variation on the electrical resistivity have been studied. Efforts of impurities doping in ZnTe films for improving the conductivity of ZnTe film are not successful on account of self‐compensation effect.
Some replica possibilities for electron‐microscope investigations of ice crystal morphology
Authors: Stoyanova V. , Genadiev N. , Nenow D. 
Published: January 2007

AbstractComparative SEM investigations have been carried out on small ice crystals by means of vapour and modified replica methods. Different replica solutions based on 3 polymers (formvar, plexiglass, polystyrene) and 3 organic solvents (methylene chloride, chloroform, ethylene dichloride) have been used. The conditions for accurate replication have been considered.
Tannic acid induced penetration twinning in gel‐grown calcium sulfate dihydrate
Authors: Cody R. D. , Cody A. M. 
Published: January 2007

AbstractWell‐formed calcium sulfate dihydrate penetration twins with twin plane a(100) are induced by the presence of gallotannic acid under alkaline conditions in bentonite clay gel. These twin closely resemble natural gypsum that occurs in alkaline desert soils.
The origin of synthetic polycrystalline skeletal diamonds
Authors: Substyk M. 
Published: January 2007

AbstractA reaction vessel for diamond production modified by using a graphite heater around a metal‐graphite sandwich set has changed the physical conditions (especially the thermal conditions) inside the set during the synthesis process. There has been built up a reduced radial temperature gradient, as compared to the gradient in a reaction vessel for repetition work. As an effect of the process polycrystals with very different shapes, morphology, and internal structure have been achieved, and they are named as skeletal polycrystals. Basing on the relation between crystal morphology and its growth conditions, in this paper a suggestion of this polycrystals' growth process is described. It is assumed that the principal driving force of polycrystals' growth process has been the supersaturation of the cobalt solution by graphite. As a result of diamond crystallization, the graphite content decreases and causes the change of growth mechanism from continuous growth through two‐dimensional nucleation to spiral growth. It is well noticed in the skeletal polycrystals' morphology.
Interdiffusion of Mn in austenitic and ferritic CrNi steels
Authors: Tariq M. , Bergner D. 
Published: January 2007

AbstractThe interdiffusion coefficients of Mn have been obtained in different austenitic and ferritic CrNi‐steels between 1000 and 1300 °C using Boltzmann‐Matano and Grube methods. The diffusion coefficients of Mn (≦ 2 wt%) were found to be independent on its concentration. Small variations in Cr and Ni contents in both types of steels showed neglegible effect on manganese diffusion. The interdiffusion results in austenitic steels are comparable with the Mn tracer diffusion in Type 316 steel. The results of diffusion of manganese in ferritic CrNi steels reported here are first to be published.
Bulk non‐radiative recombination reduction in nGaAs due to an annealing under Ga‐Al melt
Authors: Andreev V. M. , Salieva O. K. , Solov'ev V. A. , Sulima O. V. , Khammedov A. M. 
Published: January 2007

AbstractIt is shown by microcathodoluminescence and electron beam induced current investigations that efficiency of radiative recombination and the values of hole diffusion lengths in nGaAs substrate increase (up to Lp ∽ 5 μm) due to an annealing under GaAl melt. The values of the annealing critical temperature exceeding of which leeds to bulk non‐radiative recombination drop as well as optimal values of annealing temperature and duration are determined.In pAlGaAs–(p‐n)GaAs solar cells based on annealed substrates the values of open circuit voltage Uoc = 1.16 – 1.18 V under 500‐fold concentrated solar radiation as well as values of photocurrent comparable with the best results of solar cells with epitaxial nGaAs are achieved.
The current understanding of epitaxial CVD silicon layer doping in the light of modeling and theory development (VII)
Authors: Kühne H. , Schröder K.‐W. 
Published: January 2007

AbstractExtension and maximum concentration of autodoping profile are discussed for both lateral and vertical autodoping phenomena and, additionally, bearing in mind the typical course of autodoping profile as obtainable by spreading resistance technique, on the background of previously published theoretical concepts of dopant incorporation. It is shown that the “improved” (three‐step mechanism) as well as the “consequent” dopant incorporation concepts (two‐step mechanism) are suited for theoretically explaining autodoping phenomena. If no additional supposition will be stated, however, it is a consequence of the former that the concentration maximum in the profile of vertical autodoping equals the buried‐layer surface dopant concentration in agreement with non‐steady state layer doping behaviour after dopant source flow has been immediately interrupted. In the contrary the latter conception simply identifies lateral and vertical autodoping effect since autodoping above as well as beyond buried layer is controlled in the same way by parasitie dopant partial pressure in the gas.
Mass spectrometric studies of adsorption of silver on tungsten (110) surfaces
Authors: Gerth G. , Abelmann U. 
Published: January 2007

AbstractThe adsorption of silver on (110)tungsten was studied by a mass spectrometric molecular beam technique. The temporal behaviour of the flux of adatoms leaving the substrate was measured at fixed temperatures between 860 K and 1080 K for constant impinging rates over the range 0.2 · 1013 to 9.0 · 1013 cm−2 s−1.For moderate supersaturation the growth mode changed from the layer‐by‐layer growth of three monolayers to the growth of three‐dimensional nuclei (Stranski‐Krastanov mechanism). At equal rates of impinging and desorption flux, the equilibrium adatom concentration was determined and a set of adsorption isotherms was thus derived. The shape of the experimental isotherms was found to be broadly similar to that of the theoretical Fowler‐Guggenheim isotherm for a localized adsorption model. The binding energy of an Ag atom to the substrate, the lateral binding energy of a pair of atoms, the coordination number, and the vibration frequency of the adatoms for all three monolayers were obtained by suitable fitting procedures.
Growth and basic dielectric data of high quality TSCC crystals
Authors: Vaněk P. , Klöpperpieper A. , Albers J. 
Published: January 2007

AbstractTris‐sarcosine calcium chloride (TSCC) single crystals were grown from water solutions by the isothermal evaporation method. The growth solutions contained sarcosine and CaCl2 either in stoichiometric or nonstoichiometric ratio. The required phase diagram sarcosine–CaCl2H2O at 40 °C was determined by the synthetic method. PFT 400 MHz NMR was used for the analysis of organic impurities in sarcosine and TSCC. The crystals grown from both types of solutions had maximum values of the dielectric permittivity 10 to 200 times larger than those measured by other authors at comparable measuring frequencies and fields. It is discussed in terms of crystal quality.
Electrooptical investigations on a nematic two frequency addressing mixture
Authors: Stettin H. , Kresse H. , Demus D. 
Published: January 2007

AbstractThe change of the sign of the dielectric anisotropy of a nematic liquid crystal allows an active switching process in electrooptical cells in on and off direction. In the two frequency addressing mode the TN cell shows a qualitative and quantitative different dynamic behaviour in comparison to the conventional driving mode. During the switching on process hydrodynamical domains occur. After switching off the director configuration skips into the −3π/2 twist and thereby it realizes a loss in transmission. The director configuration relaxes into the quarter twist after some minutes. A superposition of low frequent and high frequent voltage gives a strong increase of the number of multiplexable lines.
Problem of multiple solutions in the Taylor model
Authors: Wierzbanowski K. 
Published: January 2007

AbstractThe Taylor model of polycrystal plasticity gives multiple solutions for some crystal orientations. This means that the slip systems, slip shears and crystal rotations are not unique. In such a case the unique prediction of crystal rotation is impossible and consequently some limitations for the texture study are imposed. We propose to eliminate this degeneration using an energetic criterion based on the anisotropic latent hardening of slip systems. We present a few examples of unique choice of slip systems and of crystal rotation.
Zeolite NaCaA as a desulphurization adsorbent – modification of its thermal and hydrothermal stability
Authors: Lutz W. , Bülow M. , Feoktistova N. N. , Vtjurina L. B. , Shdanov S. P. , Siegel H. 
Published: January 2007

AbstractThe thermal and hydrothermal stability of the zeolite NaCaA in dependence on the ion exchange degree have been investigated. The increasing thermal stability of the zeolite with increasing content of calcium ions corresponds to the higher stability of calcium silicates compared with sodium silicates. In contrast to that the decreasing hydrothermal stability is due to the decreasing alkalinity of the zeolite in aqueous media. Measurements of the pH‐value of zeolite/water slurries underline this tendency.
The influence of controlled electron‐seeking addition agents of the melt on stilbene single crystal structure and radioluminescence properties
Authors: Krainov I. P. , Galunov N. Z. , Budakovsky S. V. 
Published: January 2007

AbstractThe study of certain radioluminescence characteristics of stilbene single crystals is performed. Doping the stilbene melt with electron‐seeking (ES) addition agents of benzol and benzophenone halogen derivatives allowed to control the structure perfection of the crystal grown. The root‐mean‐square random orientation of single crystal mosaic structure, and concentration of the deep traps of charge carriers and excitons were minimum for the single crystals grown from the melt containing 0.1 mol% ES addition agent. Doping the melt with ES addition agents did not cause the appearance of additional luminescence impurity centres or quench luminescence centres in the single crystals grown.
Infrared optical properties and crystal structure of Cu2GeS3
Authors: Neumann H. , Riede V. , Sharif N. , Sobotta H. , Omar M. S. 
Published: January 2007

AbstractInfrared reflectivity and transmission spectra of Cu2GeS3 are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. From an analysis of the spectra the parameters of the fundamental infrared active lattice modes and of the two‐phonon combination modes are determined. From a comparison of the experimental data with group theoretical predictions for the structure models proposed for Cu2GeS3 in the literature it is concluded that Cu2GeS3 crystallizes in a monoclinic lattice.
Hydrothermal synthesis of (Zr0.33 Ti0.67) O2–srilankite in the system ZrO2TiO2H2OMF; (M = Na, K)
Authors: Buhl J.‐Chr. , Willgallis A. 
Published: January 2007

AbstractThe hydrothermal synthesis in the system ZrO2TiO2H2OMF; (M = Na, K) is discussed for the temperature range 573 K–773 K and the pressure of 100 MPa to 150 MPa. Starting with Zr‐ and Ti‐ butoxides their co‐precipitated hydrolysates which had been annealed in different ways were used as initial products. The formation of mixed crystals (Zr, Ti)O2 analogous to the rare mineral srilankite was dependent on the crystallinity and homogeneity of the initial products. 573 K and 100 MPa proved to be the most favourable conditions for synthesis. Higher temperatures (773 K) produced multiphase crystallizates of (Zr, Ti)O2, baddeleyite, anatas, and rutile.
MOCVD layer growth of ZnO using adducts of dimethyl‐ and diethylzinc
Authors: Kaufmann Th. , Fuchs G. , Webert M. , Frieske S. , Gäckle M. 
Published: January 2007

AbstractReaction mixtures of the tetrahydrofuran adducts of Zn(CH3)2 and Zn(C2H5)2 with tertiary butanol are very well suitable for the MOCVD of c‐axis oriented ZnO films. The deposition process is greatly determined by the kind of the gas inlet into the vertical reactor. The growth rates present a great dependence on temperature. The incorporation of compensating copper acceptors can be achieved with the help of cyclopentadienyl (tributylphosphine)‐copper (I). The structural and the electrical properties of the films are presented.
Infrared lattice vibrations in CuGe2P3
Authors: Neumann H. , Sharif N. , Riede V. , Omar M. S. , Sobotta H. 
Published: January 2007

AbstractInfrared reflectivity spectra of CuGe2P3 single crystals are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. From an analysis of the spectra the parameters of five vibrational modes are determined. The results are discussed in terms of the Keating model and are compared with lattice vibrational data for ZnGeP2, CdGeP2, and CuSi2P3.
The coprecipitation of magnesium aluminium hydroxocarbonate powders from aqueous solution: Precipitate compositions and coprecipitation mechanisms
Authors: Packter A. , Panesar K. S. 
Published: January 2007

AbstractMagnesium aluminium hydroxocarbonate hydrates were coprecipitated from mixed metal nitrate solutions, at total CM = 0.2 M and Mg/Al2 = 1 ratio, with four sodium hydrogen carbonate‐sodium carbonate solutions (of pH 8.1 to 11.5) at ambient temperature. The course of precipitation was monitored by potentiometric (pH) titration, and the compositions of the primary and final precipitates were determined by chemical analysis, infrared spectrophotometry and X‐ray diffraction.Precipitation generally occurred through three stages, primary precipitation (of low CO3 aluminium hydroxocarbonates) at low pH with evolution of carbon dioxide, their dissolution by complexing to form hydroxocarbonatoaluminate anions and then secondary precipitation of the final coprecipitate at higher pHs. The final product from coprecipitation by sodium hydrogen carbonate solution (pH 8.1) was mainly the magnesium hydroxocarbonatoaluminate ‘MAHC I’; the final products from coprecipitation by sodium hydrogen carbonate‐sodium carbonate solutions (pH 9.4 and 10.3) were ‘MAHC I’/‘MAHC II’ mixture and ‘MAHC II’/‘MAHC I’ mixture whereas the final product from coprecipitation by sodium carbonate solution (pH 11.5) was a complex mixture if ‘MAHC II’ with ‘MAHC I’ and ‘MAHC III’;

‘MAHC I’ was probably Mg2[Al4(OH)10(CO3)3] · hH2O,
‘MAHC II’ was probably Mg[Al2(OH)4(CO3)2] · h H2O whereas
‘MAHC III’ was probably Mg[Al2(OH)6CO3] · h H2O.
Properties of Ni/p–InTe Schottky barrier
Authors: Rousina Roughieh , Shivakumar G. K. 
Published: January 2007

AbstractNickel–indium telluride schottky barriers have been prepared by sequential evaporation, and their electrical characteristics have been studied. Various diode parameters have been obtained through current‐voltage and capacitance‐voltage characteristics. An equilibrium energy level diagram for the Ni/p–InTe system has been constructed using the experimental results.
The transition layers in AlGaAs/GaAs and InGaAsP/GaAs heterostructures grown by LPE
Authors: Bolkhovityanov Yu. B. 
Published: January 2007

AbstractAlGaAs/GaAs and InGaAsP/GaAs heterostructues were grown by liquid phase epitaxy (To = 800–770 °C), the transition layers (TLs) were measured with Auger profiling. The Auger profiling of the InGaAsP/GaAs heterostructures after a long heating (1–6 hours, 770 °C) has been made too. The analysis of the experimental data led to the conclusion that the fundamental values of the TL in above mentioned systems are about 10 and 1 to 2 nm, correspondingly. This difference between the minimum widths of the TL in AlGaAs/GaAs and InGaAsP/GaAs system is connected with the different speed of solid state diffusional processes which occur at the initial stpeps of liquid – solid contact.
Theoretical compton scattering profile for conduction electrons in lithium
Authors: Mosharafa A. A. 
Published: January 2007

AbstractThe theoretical Compton scattering profile of the conduction electrons in lithium is calculated for three scattering vectors, taken along the symmetry axes of the Brillouin Zone. Qualitatively, the results are in good agreament with experiment, however, quantitatively, there are some discrepancies which are probably due to correlation effects. It is desirable to have more refined experimental data.
Computer analysis of regularities of nucleation and crystal growth in a solid
Authors: Larikov L. N. , Karpovich V. V. , Dneprenko V. N. 
Published: January 2007

AbstractAn interplay between the homogeneous nucleation and growth processes during recrystallization and phase first‐kind transformation was investigated. Computer simulation taking account of unsteadility of nucleation process and possibility of elimination of potential nucleation sites at a constant growth rate allowed to obtain the time dependence of nucleation rate of the new phase, Ṅ, in the total bulk of a sample. The various kinds of the dependence Ṅ including an increase, a constancy and a decrease are obtained.
Analytical calculation of binding energies of highly symmetrical particles
Authors: Fritsche H. G. 
Published: January 2007

AbstractAnalytical formulae of binding energies per atom are derived for icosahedral, cuboctahedral and face‐centered cubic particles AN by means of summation of pair potentials. Asymptotical relations for larger particles E/N = V (A – BN−1/3) as well as the topological model of clusters are discussed.
The thermal expansion of microcracks and grain boundaries in crystals (I). A new mechanism of crack formation
Authors: Vlasov A. D. 
Published: January 2007

AbstractApart from known reasons for crack formation it may be effected by the spontaneous microcrack wall heating. This heating takes place because of crack widening and formation of relatively free surfaces (crack walls). These surfaces must have the effective temperature that is well above the temperature in the bulk of crystals, as it has been shown earlier by the author. Simple equations for the thermal expansion of microcracks had been suggested. It has been shown that at the temperature above of 0.9Tm (Tm is the melting point) for the pure metals the spontaneous, without external stresses, crack formation takes place that may cause creep and superplasticity proceeding by the diffusion mechanism. At Tm the spontaneous cracking results in the crystal crushing to the microcrystallites, that is the spontaneous cracking may be considered to be the melting mechanism. From this point of view the intensive thermal expansion of liquids in temperature range from Tm to the critical temperature involves mainly the enlargement of microcrystallite gaps. By using this supposition simple equations for thermal expansion of liquids have been proposed.
Crystal growth of Ca3−xYxMn2Ge3O12 and phase relations in the PbOB2O3GeO2 based melts
Authors: Nevřiva M. , Durčok S. , Pollert E. 
Published: January 2007

AbstractThe bulk crystals of Ca3−xYxMn2Ge3O12 garnets were grown on a seed from the PbOB2O3GeO2 based melts, where the primary crystallization field of garnets was found. The saturation temperatures of the melts were determined before each growth run. The dependence of Y incorporation into the crystals versus the melt composition was also evaluated.
Impurity distribution within the diffusion layer in the cluster crystallization model
Authors: Zharikov E. V. , Zavartsev Yu. D. , Laptev V. V. , Samoilova S. A. 
Published: January 2007

AbstractThe impurity distribution in front of the surface of the growing crystal by Czochralski method is considered at the assumption that the crystallization begins in the melt within the diffusion layer by the formation of clusters, i.e. it has an extented nature. The moving force of the crystallization is the supercooling of the melt. The principle distinction from the classical BPS theory is that the concentration profile has no break near the meltcrystal interface and is defined by the impurity concentrations both in the liquid and cluster phases with allowance for their specific volumes.
Effects of melt composition on structural and electrical characteristics of LEC Si‐doped gallium arsenide
Authors: Fornari R. 
Published: January 2007

AbstractThe aim of this paper is that of briefly reviewing the experimental observations carried out on Si‐doped gallium arsenide grown from off‐stoichiometry melts (either Ga‐ or Asrich) in the author's laboratory. It will be shown that the melt composition strongly affect the electrical (electron mobility, density of deep levels) and structural (dislocation density, precipitates) properties of the bulk crystals which proves the existence of a link between point defects and physical and crystallographic characteristics. The experimental results will be discussed considering recent literature reports on point defects in bulk GaAs.
Infinite symmetry applied to crystals and crystal aggregates
Authors: Kostov R. I. , Kostov I. 
Published: January 2007

AbstractInfinite symmetry is referred to for describing in a more rational manner the morphology of certain crystals and crystal, particularly mineral aggregates. Their non‐crystallographic forms depend on the peculiarities of their structure, enhanced growth along preferred directions and on the symmetry and composition of the growth environment. Apart from the seven Curie forms others, fitting the corresponding point groups are suitably added as variants of the growth geometry, applicable also to the property of matter.
EPR and pulsed NMR study of (NH4)2ZnBr4:Mn2+
Authors: Rao P. Madhusudana , Reddy K. V. 
Published: January 2007

AbstractThe EPR and pulsed NMR measurements of (NH4)2ZnBr4:Mn2+ have been carried out in the temperature range 110–473 K and 83–284 K, respectively. EPR spectra from three different paramagnetic entities have been observed. Intensity changes of certain lines in the EPR spectrum observed at ≈ 430 K indicate the occurrence of a phase transition. Another phase transition at ≈ 235 K is indicated as a change of slope in the T1 vs 1/T curve.
X‐ray powder diffraction investigations of solid solutions in the KClKBrH2O system at 298 K
Authors: Dejewska B. , Sȩdzimir A. 
Published: January 2007

AbstractThe measurements of crystal lattice parameters (a) of solid solutions being formed in the system KClKBrH2O at 298 K were conducted. The volumes (v) of unit cells and the densities (ϱ) of mixed crystals K(Cl, Br) were calculated. It was confirmed that in the investigated system continuous solid solutions were formed. The lattice parameters of these crystals formed from aqueous solutions of salts as well as from molten salts and also calculated by Durham‐Hawkins method were nearly identic.