bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on epitaxial growth of organic compounds on sucrose by the fourier transform method (I). On crystal growth of the participants
Authors: Adler H.‐J. , Follner H. 
Published: January 2007

AbstractEpitaxial growth of organic compounds on sucrose crystals has been observed. In any case two‐dimensional lattice analogies exist. The structural relations are, as a rule, unknown. In the present first part crystal growth of the participants was investigated. Equilibrium and growth forms of host (sucrose) and guest crystals (β‐succinic acid, hexachlorobenzene, anthraquinone, isatin) have been determined by the Fourier transform method. The growth polyhedra fully correspond to the experimental observations.
RHEED Measurements of AgGaSe2 thin films flash evaporated onto {111} a‐GaAs
Authors: Tempel A. , Schumann B. , Kühn G. 
Published: January 2007

AbstractAgGaSe2 thin films were prepared by flash evaporation on {111} A‐oriented GaAs substrates and investigated by reflection high energy electron diffraction (RHEED). Epitaxial growth takes place in the substrate temperature interval of Ts = 845–920 K. The azimuthal orientation of the deposit on the substrate is discussed, supposing a AgGaSe2 c/a ratio of 1.82. It is shown that detection of twin formation in the films is possible from RHEED measurements in the <211>‐azimuths with respect to the substrate.
Microstructure and spacings of directionally solidified metal‐semiconductor eutectic alloys
Authors: Vetter J. , Frühauf J. , Schmidt G. 
Published: January 2007

AbstractDirectionally solidified metal‐semiconductor eutectic alloys, representing nonfacetted facetted eutectics, show a variety of microstructures caused by the great differences in semiconductor volume fraction (ZnGe 7,8 %; GeZrGe2 98.6 %), the influence of growth rate and temperature gradient at the solid‐liquid interface. The AlSi, AgSi, AgGe, ZnGe, Cu3SiSi, NiGeGe, CoGe2Ge, Mn3Ge2Ge, FeGe2Ge, Mn11Si19Si, Cu3GeGe, GeTiGe2 and GeZrGe2 eutectics habe been investigated. The following three models are applicable for the calculation of the spacings as a function of growth rate and temperature gradient at the solid‐liquid interface to certain microstructures: diffusion‐determined growth, branchinglimited growth and phase‐lead‐determined growth.
Electronic structure investigation of V1−xNbxO2 mixed oxide by XES and XPS
Authors: Werfel F. , Rohländer D. 
Published: January 2007

AbstractThe mixed oxide system V1−xNbxO2 (x ≦ 0.12) has been studied by X‐ray and photo‐emission spectroscopy as a function of the composition. The metal L valence band spectra (VLIII and NbLβ2.15) with increasing Nb concentration change their width and relative band intensity substantially pointing to charge flow and hybridization effects. The XPS valence band for x ≧ 0.04 indicates a total d band shift of 0.4 eV relative to smaller Nb concentrations. The measured core level spectra at higher Nb doping x ≈︁ 0.10 support the expected existence of V3+‐Nb5+ pairs. A comparison of different X‐ray spectra and the XPS valence band spectrum for x = 0.08 exhibits a more stronger V3d localization relative to Nb4d, favouring charge transfer and bonding variations with Nb doping. Our spectroscopial data confirm the established ideas concerning the electronic structure of rutile‐like compounds and its change at the phase transition point.
Vapour Phase Epitaxy of GaxIn1−xAs in the GaInHClAsH3H2‐System Using a Mixed Ga/In Source
Authors: Jacobs K. , Bugge F. , Simon I. 
Published: January 2007

AbstractThe mixed crystal composition of GaxIn1−xAs layers is analysed as a function of the composition of a mixed Ga/In source during VPE in the hydride system. Experimental results are compared with thermodynamic calculations. Both thermodynamics of the deposition reactions and thermodynamies of the souree reactions are considered in the calculations.
Main Factors Influencing the Crystal Size Distribution from a Batch Cooling Crystallizer
Authors: Chianese A. , Di Cave S. , Mmazzarotta B. 
Published: January 2007

AbstractAn experimental investigation was carried out with a view to characterizing the influence of some typical operating factors on the size distribution of the crystal product obtained from a batch cooling crystallization. Reference was made to K2SO4 crystallizing from aqueous solutions, a system for which some data are available in the literature making possible some interesting comparisons. The obtained results indicate that a consistent improvement of the product size distribution can be achieved by limiting the stirring rate, by the use fo seeding, and by the presence of a draft‐tube, in that order; little in‐fluence seems to have the cooling medium temperature. Quite important is also the cooling policy adopted and in this sense a linear cooling curve lead to the best product quality.
Techniques for Generation of Supersaturation Applicable to the Precipitation of Barium Chromate
Authors: De Silva R. L. , Creasy D. E. 
Published: January 2007

AbstractPossible techniques for generating supersaturation, which could be applied to precipitation of barium chromate from aqueous solution, are reviewed, and experimental work carried out to examine the feasibility of the more promising of these techniques are described. The process requirements of a reasonable rate of production of relatively large (∼ 100 μm) crystals of normal habit, are shown to be satisfied by the technique of precipitation from homogeneous solution (PFHS), employing urea hydrolysis to cause a controlled change in the solubility of barium chromate in an acidic aqueous medium. Some recent experimental work on urea hydrolysis, as applied to the precipitation of barium chromate, has been reanalysed and found to be in agreement with the generally accepted, pseudo‐first order reaction model. The effects of urea hydrolysis on the precipitation process are discussed.
Structural Changes During Cutting of Mo Crystals
Authors: Larikov L. N. , Maximenko Ye. A. 
Published: January 2007

AbstractStructural changes occurring in a shaving and in product during cutting of Mo single crystals as well as softening processes during annealing after cutting are investigated.The extremal deformation are created when the shaving is removed and as a result the dynamic recovery process with lattice reorientation takes place.The strong deformation heterogeneity, which is revealed as the two‐scale recrystallisation processes during isothermal annealings, and its localisation in separate sections of the specimens was observed.During high‐temperature annealings of the product and shaving the matrix‐crystal orientation recovery occurs by means of absorption of the recrystallised layer by undistorted matrix.
Peak Position Determination of X‐Ray Diffraction Profiles in Precision Lattice Parameter Measurements According to the Bond‐Method with Help of the Polynomial Approximation
Authors: Grosswig S. , Jäckel K.‐H. , Kittner R. 
Published: January 2007

AbstractThe possibilities and limits of the polynomial approximation for an accurate determination of the peak position of X‐ray diffraction profiles in precision lattice parameter measurements according to the BOND‐method are investigated. The use of a polynomial approximation with reciprocal measuring values leads to an improvement of the convergence properties of the approximation and allows to use polynomials with lower degree. A practicable criterion of the choise of optimum approximation parameters is given. It is shown that the accuracy of the determination of the peak position which is needed for precision lattice parameter measurements with an accuracy of about Δd/d ≈︁ 10−7 is attainable under usual experimental conditions.
Unusual Thermal Behaviour of Mercurous Chloride
Authors: Venudhar Y. C. , Iyengar Leela , Rao K. V. Krishna 
Published: January 2007

AbstractA precise determination of the lattice parameters and the coefficients of thermal expansion of mercurous chloride has been made at different temperatures ranging from 30 °C to 260 °C with a Unicam 19 cm high‐temperature powder camera and FeKα radiation. The ‘a’ parameter increases non‐linearly, whereas the ‘c’ parameter decreases linearly with temperature. Both the c/a value and the unit‐cell volume are found to decrease with increasing temperature. The coefficient of thermal expansion along the ‘c’ axis, α∥, is found to have a constant negative value throughout the range of temperature studied. The positive value of α⊥ increases while the negative value of volume coefficient (β) decreases linearly with increasing temperature indicating an unusual and interesting thermal behaviour.
X‐Ray Determination of the Mean Amplitude of Vibration and Debye Temperatures of KRS‐5 (TIBr0.46I0.54)
Authors: Srinivas K. , Sirdeshmukh D. B. 
Published: January 2007

AbstractThe X‐ray diffraction intensities of Bragg reflections have been measured for KRS‐5 (TIBr0.16I0.54) at room temperature. From the observed intensities the mean Debye‐Waller factor and the X‐ray Debye temperature have been evaluated. The values of the Debye‐Waller factor, mean square amplitude of vibration and the Debye temperature are 2.73 ± 0.06 Å2, 0.104 ± 0.002 Å2 and 90 ± 1 K, respectively.
The Precipitation of Alkaline‐Earth Metal Polyacrylate Hydrate Powders from Aqueous Solution: Ionic Equilibria, Precipitate Compositions and Morphologies
Authors: Packter A. , Sabir S. 
Published: January 2007

AbstractThe precipitation of barium, strontium, calcium and magnexium polyacryate hydrates was studied from equivalent aqueous solutions of initial concentrations 0.03 M to 0.30 M at ambient temperature: sodium polyacrylate (m. wt = 30,000 to 300,000) was added to metal chloride solution. The final yields of precipitate increased with decreasing solubility and/or peptisation (Ba > Sr > Ca > Mg) and increasing molecular weight of the polyacrylate; the precipitates had the compositions [BaA(COO)2 · 1–2H2O]n, [SrA(COO)2 · 1–2 H2O]n, [CaA(COO)2 · 2 H2O]n and [MgA(COO)2 · 2 H2O]n.The final yields of the precipitates from sodium polyacrylate solutions were far lower and these had the compositions [Na2αM1‐αCA(COO)2 · 2 H2O]n; A = CHCH2CH.The metal polyacrylate hydrate powders consisted of microcrystalline ‘spherules’; their average diameters were from 0.03–0.05 μm (for lower m. wt products) to 0.01 to 0.02 μ,m (for higher m. wt products).
Thermodynamic Calculation of the Alloy Composition of GaxIn1−xAs Grown in the Trichloride System Using Solid Sources
Authors: Simon I. , Jacobs K. , Butter E. 
Published: January 2007

AbstractThe dependence of the GaxIn1−xAs alloy composition as a function of the experimental input variables is calculated for a growth system using AsCl3 and solid GaAs and InAs sources. The results are similar to those earlier obtained for growth in the hydride system. Additional AsCl3 introduced downstream the source regions shifts the alloy composition towards higher GaAs content.
Luminescence and Photoconductivity Caused by Antisite Defects in CdIn2S4 Single Crystals
Authors: Georgobiani A. N. , Gruzintsev A. N. , Ratseev S. A. , Tezlevan V. E. , Tiginyanu I. M. , Ursaki V. V. 
Published: January 2007

AbstractResults of a study of the influence of nonstoichiometry as well as of annealing and argon ion implantation on photoluminescence and photoconductivity spectra of cadmium thioindate single crystals are presented. The energy positions of levels of antisite Incd and CdIn defects are found. The role of antisite defects in the process of conductivity compensation is analysed.
The Role of Impurity Precipitation on Ionic Conductivity of NaCl:Sr System
Authors: Reddy K. Narasimha , Sayanna R. 
Published: January 2007

AbstractIonic conductivity studies of NaCl crystals doped with 1 mole% of strontium both in as grown state and after quenching them from 550°C indicate that the conductivity depends on the impuritiy precipitates. It is found that all conductivity plots of pure NaCl, NaCl:Sr and NaCl:Sr crystals quenched from 550°C are straights lines, both in extensive and intrensic regions. The conductivity of NaCl: Sr system is always less than that of pure NaCl crystal. The results are explained on the basis of state of dispersion of impurities.
Quantitative Phase Analysis of Mixtures Containing α‐, β‐Tungsten and WO2
Authors: Salewski W. , Kiessling F. M. 
Published: January 2007

AbstractFor incandescent lamp wire fabrication various powder metallurgical steps are necessary. The stepwise reduction of WO3 to the tungsten metal powder is one of these. During reduction chemical reactions take place under participation of doping elements (K, Si and Al) causing the structure of non‐sag wires. The origin of secondary β‐W like an indicator for the activity of dopings has been attributed importance. Therefore it has been developed a method for quantitative phase analysis of α‐W, β‐W, WO2 mixtures consisting of oxidation value determination to establish the WO2 content and X‐ray phase analysis for a quantitative separation of the α‐W and β‐W content. The influence of extinction effects caused by particle size has been investigated and it is proposed a correction method of the measured integral intensities as a function of half‐width of the (110) α‐W reflex. In regard of the obtained results the formation of the tungsten suboxide W3O has been excluded.
Dynamic Behaviour of Ferroelectric Liquid Crystalline Thin Layers in Electric Fields
Authors: Schiller P. 
Published: January 2007

AbstractThe direction of the spontaneous polarization of a thin ferroelectric liquid crystalline film can be switched up and down between two stable states by applying an electric field. This process is investigated theoretically using the elastic continuum theory of liquid crystals. There are found two reorientation mechanisms with different switching rates. The regimes of fast bulk switching and relatively slow domain wall motion are separated by a critical threshold field.
On the Bindings in VOm Phases
Authors: Schubert K. 
Published: January 2007

AbstractThe phenomenological plural correlations model permits to attribute to the intermediate phases of the mixture VOM bonding types (bindings) which indicate a low energy of the empirically found structures. In the phases various electron subsystems exist which contain lattice‐like spatial correlations, and when the corresponding cells are in energetically low commensurabilities (in harmonies) to the crystal and to one another then the phase becomes stable. A fundamental assumption of a binding analysis is the electron count being here V1,4,8O0,6,2. As a consequence the phases V8O, V16O3, and V7O4 consist of a tetra‐gonally deformed V(B1) partial structure with interstices partly filled by O atoms. The composition of a phase determines the electron concentrations in the subsystems, and these influence the harmony of the correlations in the binding (BFU2 for V16O3, e.g.). In VO, V13O16, V2O3, and V3O5 an essentially complete close packed partial structure of O accepts V into its octahedral interstices. Once more harmonies of electron correlations determine favourable bindings (FF'2 for VO e.g.). The Magnéli phases V4O7 up to V8O15 being shear homeotypes of VO2 · h may be considered as homeodesmic to TiO2 · r, which is stabilized by a CFU2 binding. From the binding it may be concluded how much Hund insertion is present in a phase. Hund insertion is for instance responsible for the transformation VO2 · h → r. The phases V6O13, V4O9 and V3O7 are homeotypic to V2O5. This last phase permits presumably a UHT3 binding. The results of the binding analysis of VOM shed some new light on the interpretation of properties of the VOM phases.
Rolling Textures Predicted by the Elasto‐plastic Self‐consistent Model
Authors: Wierzbanowski K. , Ahzi S. , Hihi A. , Berveiller M. 
Published: January 2007

AbstractThe rotation rate fields of a f.c.c. polycrystal deformed by rolling have been predicted by the self‐consistent model for different values of the plastic accomodation parameter. The isotropic as well as anisotropic hardening of slip systems have been taken into account. The obtained rotation rate fields have been applied next to the continuity equation of texture evolution. All the results may be classified into two groups: a copper type texture and a transition texture (probably towards the brass type one).
Dry Patterning of Al and Al Alloys
Authors: Sameith D. , Tiller H.‐J. , Breitbarth F.‐W. 
Published: January 2007

AbstractPlasmachemical etching of Aluminium in chlorine containing discharges is discussed from a thermochemical point of view. A model of Al etching is proposed, in which diffusion of reaction products through the carbon‐rich deposite layer is considered to be rate‐limiting. The model quantitatively describes the dependence of the etch reaction on different process parameters of the CCl4‐plasma.
SixGe1−xGaAs Heterojunction IMPATT‐Diodes
Authors: Brailovskii E. J. , Matveeva L. A. , Meľnikov G. D. , Mikhailov J. F. , Semenova S. N. , Tkhorik J. A. , Khazan L. S. , Laichter V. , Červenák J. 
Published: January 2007

AbstractExperimental research IMPATT‐diodes on heterostructures SixGe1−x‐GaAs showed that the interphase boundary is noted with high thermal and radiation resistance. It is shown that such diodes are an equivalent alternative IMPATT‐diodes with type of Schottky barrier.
Investigation of Acoustic and Optical Properties of Ferro‐ and Piezoelectrics by the Optoacoustic Method
Authors: Golenishchev‐Kutuzov V. A. , Migachev S. A. , Rez J. S. 
Published: January 2007

AbstractA review of applications of optoacoustic methods, based on the pulse laser generation of the ultrasonic waves in samples studied is given. The paper demonstrates the possibilities of this method in determine the elastic, photoelastic, piezoelectric constants, optical quality and damage stability of ferro‐ and piezoelectrics.
Geometrical Aspects of the Patterns of Conduction Paths in Fast Ion Conductors
Authors: Fischer W. 
Published: January 2007

AbstractA method for a straightforward calculation of geometrically privileged conduction paths in fast ion conductors is presented. It makes use of a special property of Dirichlet domains, namely that their vertices and edges define all polyhedral voids and all least narrow connecting passages within a rigid framework. The results of the procedure are exhaustive in the geometrical sense and may be used as a basis for physical investigations. The method is illustrated by two simple examples, α‐AgI and sodium β‐alumina. Restrictions are discussed.
Photoluminescence from Thermally Treated CaO Single Crystals
Authors: Garcia J. A. , Remon A. , Piqueras J. 
Published: January 2007

AbstractPhotoluminescence emission and excitation spectra of CaO single crystals change strongly by annealing in air while rapid quenching does not produce new bands. The increase of an excitation band at 340 nm and the shift of the emission peaks are the main annealing effects observed. These changes, which are reduced by increasing the crystal thickness, have been found to be localized in the surface.
Stoichiometry of Thin Layers of CuInSe2 Investigated by ESCA
Authors: Sommer H. , John W. , Meisel A. 
Published: January 2007

AbstractThe stoichiometry of thin epitaxial layers of CuInSe2 on CaF2 and GaAs substrates was determined by the ESCA method. Substrate temperature was varied. It was found, that layers of exact stoichiometry are got at substrate temperatures around 700 K.
The Effect of Additions of Mn and Fe on the Structure of an Al‐2 at.% Zn‐1 at.% Mg Alloy
Authors: Löffler H. , Korngiebel E. , Dutkiewicz J. , Salawa J. 
Published: January 2007

AbstractThe structure of an Al‐1.9 at.% Zn‐1.3‐at.% Mg mother alloy with additions of Mn and Fe, respectively, were investigated by TEM and microprobe analysis for two different heat treatments, namely direct quench from 490 °C to 160 °C and a two‐step ageing treatment (preageing at RT for 7d before storing at 160 °C), to explain the differences in the course of the hardness obtained during the ageing at 160 °C. The differences of the structure observed are explained in terms of the tendency of the additives to form intermetallic phases, particularly in the grain boundaries.
Dissolution Kinetics and Etch Pit Morphology of CaF2 Single Crystals
Authors: Nicoarǎ I. , Aczel O. F. G. , Nlcoarǎ D. , Schlett Z. 
Published: January 2007

AbstractThe effect of temperature and concentration of HCl aqeous solutions on the etching behaviour on the face {111} of CaF2 single crystals is investigated. It has been observed that the shape and the evolution of etch pits and the values of dissolution rate depend on the etching conditions. From the plots of logarithm of dissolution rate versus inverse of absolute temperature the values of activation energy and the pre‐exponential factor for the dissolution process are computed. It has been found that the value of the activation energy and of the pre‐exponential factor do not remain constant with acid concentration, but exhibit a minimum for the concentration of 6 N.
The Dimer Association of Stearic Acid in Solution
Authors: Garti N. , Sato K. , Schlichter J. , Wellner E. 
Published: January 2007

AbstractThe dissociation constant of stearic acid was determined in four different solvents, using the Fourier Transform Infrared technique. The ΔH values obtained for each solvent decrease as the solvation of stearic acid increaes. The results are relevant to the crystallization process of stearic acid from solution which may lead to different polymorphic forms depending on the different crystallization parameters.
The Effect of Solid and Liquid Inclusions on Morphology of Crystallization Front
Authors: Ovsienko D. E. , Fedorov O. P. , Kiriyevsky B. A. , Gershtein G. I. , Chemerinsky G. P. 
Published: January 2007

AbstractThe interaction between crystallization front and solid particles was studied for substances characterized by the normal growth mechanism (continuous growth). It has been measured the critical velocity below which the particle of radius R is repulsed by moving interface and above it is captured. It has been shown that critical velocity is proportional to R−(1.4–1.8) what satisfactorily agrees with Chernov‐Temkin's theory. Data have been received about change of interface morphology at capture of solid particles for growth from pure and impurity‐contained melt. The dendrites have been found to split at interaction with particles and concentration inhomogeneities. Taking for example Al‐Cu alloy, possibility has been shown to disperse the dendritic structure by formation concentration inhomogeneities in the melt.
Determination of Molar Ratio in AB1−x Rocksalt‐type Compounds by X‐ray Powder Diffraction Method. Application to TiC1−x
Authors: Čapková P. , Karen P. , Dobiášová L. 
Published: January 2007

AbstractThe B/A molar ratio in AB1−x rocksalt‐type compounds is determined by X‐ray powder diffraction method by measuring of integrated intensities Ihkl. The strategy of measurement is presented to avoid all effects influencing the integrated intensities of X‐ray powder diffraction as primary extinction, preferred orientation and surface roughness effect. This paper deals with application of this method to the determination of the deviation from stoichiometry of TiC1−x compounds.
Burgers Vectors of Dislocations in Creep‐deformed Fe3Si Single Crystals
Authors: Krämer U. , Oertel C. G. , Zies G. , Kleinstück K. 
Published: January 2007

AbstractIn creep‐deformed Fe3Si single crystals the Burgers vectors of the dislocations were examined by transmission electron microscopy. The Burgers vector in a sample deformed under conditions of 60 MPa and 575–600 °C was of the type 1/2 〈110〉, whereas 〈111〉 superlattice dislocations were not found. 1/2 〈110〉 is the shortest translation distance in the D03 superlattice structure of Fe3Si.