bluuebunny/crossref_metadata_2025_split huggingface dataset:
A note on the mechanics of diffusion of defects in solids
Authors: Michel B. , Michael D. 
Published: January 2007

AbstractThis paper deals with diffusion of point defects due to lattice deformations around the defects. The continuum theory of lattice defects is applied to derive suitable diffusion equations taking into consideration the fields of self‐stresses caused by the drift of defects. The model is applied to defects near surfaces and interfaces. The interesting phenomenon of “near‐surface Cottrell atmospheres” is discussed. The authors show that Cahns theory of spinodal decomposition is included in the model as a special case.
On batch homogeneity in horizontal CVD reactors (II). HCl gas‐phase etching
Authors: Richter F. , Morgenstern Th. , Sperling R. 
Published: January 2007

AbstractA general model of the depletion is given, to which the reactive component of the reaction gas mixture in a horizontal CVD‐reactor is subjected during its flow along the heater. Furthermore the model of heating the process gas, described in Part I of this work, is used to derive an expression of the dependence of the thickness δ of the boundary layer upon the x‐coordinate (direction of the flow). Both models are combined to get a model of longitudinal homogeneity of wafer processing in an CVD‐reactor, which is applied to the special case of HCl gas phase etching. The predictions derived using the model were compared with experimental results.
Modelling crystal growth rate of barium chromate precipitated from homogeneous solution
Authors: De Silva R. L. , Creasy D. E. 
Published: January 2007

AbstractAn empirical power law type model, used for modelling crystal growth rate of barium chromate, when precipitation was carried out from homogeneous solution, has been applied to the re‐analysis of experimental data, based on which an unusual inverse size dependence on growth rate had been claimed previously. It is shown that the current empirical model provides a more realistic explanation of the data. The weaknesses of the previous approach are discussed in comparison with this new model.
Mathematical modelling and optimization of a molten phase crystallizing process
Authors: Bezegh A. , Domokos L. , Gàl S. 
Published: January 2007

AbstractA mathematical model of a new process has been developed. A two‐dimensional function of a particle population density was defined on the phase space of mass and enthalpy. The basis of the model is the description of this density function at different stages of the process. The collision of particles followed by a coalescence is the sink and source of the particles. These events are related to the state of the total system and to the position of the particle in the phase space, and are proportional to particle density, particle cross section, particle velocity differences and residence time of particles. A computer program was written for calculations and for finding an optimum to the parameters of the process. The computations were carried out using the data for sorbitol crystallization.
Growth of n‐octacosane crystals from completely and partially stereo irregular solvents
Authors: Prasad P. B. V. , Raju I. V. K. Bhagavan 
Published: January 2007

AbstractThe growth of n‐alkane crystals from completely and partially stereo irregular solvents is reported. A sharp rise in the frequency of occurrence of simple and complex (interlaced) spirals is observed as the solvent characteristic changes from complete to partial stereo irregularity of the molecular chain. These observations are interpreted taking into consideration the acceptability of the solvent molecules as impurity in the growing crystal.
Influence of substrate orientation on the electrical properties of CuInSe2 epitaxial layers on GaAs substrates
Authors: Neumann H. , Nowak E. 
Published: January 2007

AbstractThe electrical properties of CuInSe2 epitaxial layers on (111)A‐, (110)‐, and (100)‐oriented GaAs substrates are investigated. At substrate temperatures Tsub ≧ 820 K the p‐type conductivity observed is governed by an acceptor state with an ionization energy of about 110 meV independent of the substrate orientation. At Tsub ≦ 770 K three different acceptor states are found in dependence on the substrate orientation: 390 meV for (111)A‐, 110 meV for (110)‐, and a very shallow acceptor for (100)‐oriented substrates. A possible correlation between these acceptor states and intrinsic defects is proposed.
Structural changes in MgO by activation in a planetary mill
Authors: Steinike U. , Kretzschmar U. , Tolochko B. 
Published: January 2007

AbstractMechanical activation of MgO in a planetary mill results in structural changes comparable to those observed in a vibration mill. Under the given conditions they are, however, achieved in considerable less time. Furthermore, a so far unreported lattice dilatation could be observed. The activated MgO showed an increased reactivity with respect to the ambient atmosphere. As a result magnesium hydroxide and a basic magnesium carbonate are formed.
Numerical calculation of marangoni convection in a rectangular open boat
Authors: Wilke H. , Löser W. 
Published: January 2007

AbstractNumerical calculations of the flow caused by thermocapillary forces at the free surface in NaNO3 and Si melts in an open boat geometry have been carried out. The results agree well with measured flow velocities in model experiments for crystal growth configurations with NaNO3 melts. For Si melts a transition to a more complicated multiple eddy flow occurs. The projection‐iteration method used for the calculations is much more effective than the finite difference methods applied until now and is especially advantageous for more complicated flow patterns.
The dependence of surface morphology of GaSb‐ and AlxGa1–xSb epitaxial layers on the conditions of LPE growth
Authors: Yordanova I. M. , Pramatarova L. D. 
Published: January 2007

AbstractThe present work shows the dependence of surface morphology of the GaSb and AlxGa1–xSb epitaxial layers on the conditions of LPE growth. It is found that for LPE growth at 500 °C a supersaturation of 5—10 °C and a cooling rate of 0.24—0.4°C/min for GaSb epitaxial layers and 0.8—1.2 °C/min for AlxGa1–xSb epitaxial layers is necessary to obtain a flat and smooth surface.
Instability of “slow” solid‐liquid interface relaxation before the hetero‐LPE of III‐V compounds
Authors: Bolkhovityanov Yu. B. , Chikichev S. I. 
Published: January 2007

AbstractResults of specially designed experiments supplemented by numerous literature examples have been analysed in attempt to elucidate the processes occurring at the interface between saturated multicomponent liquid and a non‐equilibrium solid before the hetero‐LPE of nearly lattice‐matched III–V compounds. The “slow” interface relaxation which provides the moving of non‐equilibrium solid‐liquid system in the direction of thermodynamic equilibrium by solid‐state diffusion (and which was previously believed to be the only way of equilibrium approach in lattice‐matched systems) looses the stability in some cases, being replaced by “fast” relaxation. It has been shown that the liquid‐solid interface instability develops due to a collective action of several factors, and their particular combination produces definite mode of relaxation. The “slow” relaxation would be unstable, if, as a result of underlying solid dissolution: (1) the lattice parameter of equilibrium solid decreases continuously with respect to that of the substrate, increasing thereby the driving force for dissolution; (II) the solubility of group V component in a changed liquid increases. In a majority of cases the switching to “fast” relaxation is facilitated by (III) the initial negative difference between the lattice parameters of equilibrium and underlying solids at the growth temperature.
Reciprocal crystal and P.B.C.‐vector method. Crystal growth of a‐sulphur
Authors: Follner H. 
Published: January 2007

AbstractThe morphological lattice of α‐sulphur (F ddd) has coordinates 1/8, 1/8, 0. The reciprocal crystal is a polyhedron with 15 faces and point symmetry 112. The arrangements of the polyhedra parallel to the crystal faces confirm that (100), (101), (010), (011), (111), (113), (001) are F‐faces and (110), (112) S‐faces according to Hartman and Perdok. Under consideration of the extinction rules of the morphological lattice (101) and (011) have to be regarded as S‐faces. The size of the polyhedra faces is proportional to the interaction energy given by Hartman. It will be shown that the face area of the net planes, divided by the number of molecules per growth layer, represent a good approximation to the attachment energy calculated according to Hartman. The average deviation for α‐sulphur is 3%, for olivine and SnJ4 8.5% and for anthracene 10.5%. The Wulff‐plots correspond fully to the experimental observations.
Influence of source composition on the properties of flash‐evaporated thin films in the Cu–In–Se system
Authors: Neumann H. , Schumann B. , Nowak E. , Tempel A. , Kühn G. 
Published: January 2007

AbstractUsing CuIn2Se3.5 as source material epitaxial layers are obtained on (111)A‐ und (100)‐oriented GaAs substrates by flash evaporation in the substrate temperature range Tsub = 720—870 K. The composition of the films is between CuInSe2 and CuIn2Se3.5. The structural properties of the films are similar to those for CuInSe2 epitaxial layers and refer to a chalcopyrite‐like structure. The films are always p‐type conducting but different acceptor states are found in dependence on the substrate temperature.
Discontinuous Freedericksz transition in the smectic C phase
Authors: Schiller P. , Pelzl G. 
Published: January 2007

AbstractThe threshold field of the Freedericksz transition in planar oriented SC monocrystals possessing positive dielectric anisotropy is calculated for two boundary conditions. It is shown that the threshold field is relatively low when a discontinuous transition is taken into consideration. The effective elastic constant is determined from the experimental data.
Influence of crystallization conditions on the size of cellular and cellular‐dendritic substructure
Authors: Esin V. O. , Vorontsov V. B. 
Published: January 2007

AbstractA relationship is shown to exist between the size of the cellular‐dendritic substructure and the growth conditions. The dependence of the cell diameter on the crystallization rate is non‐monotonic, having a maximum in the region of low solidification rates. Theoretical calculations are compared with experimental data.
Metastable zone width in salting‐out crystallization
Authors: Karpinski Piotr H. , Nývlt Jaroslav 
Published: January 2007

AbstractMeasurements of the metastable zone width, giving information on nucleation characteristics, have been used for crystallization by cooling until now. This approach is now adopted for salting‐out of inorganic salts from aqueous solutions by addition of an organic solvent. Theoretical description is illustrated by precipitation of magnesium sulphate using methanol and ethanol as second solvents.
A new method of site occupancy analysis in substitutional mixed crystals by means of X‐ray crystal structure analysis (I). Pseudo lattice and superposition structure of a substitutional mixed crystal
Authors: Zedler A. 
Published: January 2007

AbstractIn Part I the nature of disorder in mixed crystal structures will be discussed on the basis of a pseudo lattice concept. A mixed crystal pseudo lattice applicable to all atomic positions of these mixed crystal structures will be defined, and the concept of a statistically globaldisordered ideal structure will be introduced. The structure factor for mixed crystal structures will be derived in consideration of the statistic disorder of position and sort of the atoms. The interpretation of the mixed crystal structure as a superposition structure requires the replacement of Vegard's rule by a new one having a wider range of validity.
On the substructure of epitaxial (Pb, Sn)Te films grown on KCl cleavage faces
Authors: Schenk M. , Tap Ngo Dien 
Published: January 2007

AbstractThe X‐ray diffraction rocking curve analysis has been employed for the measurement of crystallite sizes of (Pb, Sn)Te films for different thickness, epitaxially grown on KCl cleavage faces by the hot‐wall technique. The size of the coherently scattering regions parallel to the reflecting planes did not depend on film thickness and agreed with the mean distance of nuclei just before coalescence, investigated by means of replica electron microscopy. The results are consistent with a model of stalk‐like growth of crystallites in film growth direction.
The crystal structure of butylammonium dodecylsulfate
Authors: Szulzewsky K. , Schulz B. , Vollhardt D. 
Published: January 2007

AbstractC16H37NO4S, monoclinic, P 21/m, a = 25.398(11), b = 7.366(4), c = 5.459(3) Å, β = = 91.53(4)°, Z = 2, V = 1020.91 Å3, Dx = 1.104 g/cm3, μ(MoKα) = 0.175 mm−1, λ(MoKα) = 0.71069 Å. The crystal structure of this anionic surfactant was solved by Patterson methods and refined to R = 0.109 for 2497 reflections. Dodecyl‐ and butylchains are statistically disordered. Loose package of butyl chains enables strong vibration motions. The polar region satisfies the mirror plane which is by the remaining structure parts only statistically fulfilled. Statistical disorder was included in the structure refinement by separation of some atom positions. The sublattice of the hydrocarbon chains is nearly O⟂ with as = 4.77, bs = 7.37, cs = 2.52 Å.
Temperature dependence of the X‐ray diffuse scattering intensity in V3Si in the temperature range from 8 to 300 K
Authors: Sirota N. N. , Polutchankina L. P. , Orlova N. S. 
Published: January 2007

AbstractMeasurements of the diffuse X‐ray scattering are performed from the (110) plane in V3Si single crystal at different temperatures from 300 to 8 K. Contours of equal diffuse scattering intensity are drawn over the 440 node in the (001) and (111) sections. The temperature dependence and the anisotropy of the thermal diffuse scattering intensity distribution for this compound are analysed.
Low ohmic multilayer contacts in lead‐Tin‐Telluride diode lasers
Authors: Herrmann Ka. , Sumpf B. , Böhme D. , Hannemann M. 
Published: January 2007

AbstractThe preparation and the influence of low ohmic multilayer thin film contacts of lead‐salt homo‐ and heterolasers on the degradation of lasing parameters during recycling processes between low working temperatures and room temperatures storage are described and discussed in detail.
Dendritic growth forms of borax crystals
Authors: Takoo R. K. , Joshi M. S. , Patel B. R. 
Published: January 2007

AbstractA variety of dendritic forms of borax grown from solutions by the film formation method is given. The changing growth morphology is followed as a function of concentration and temperature. The initial, intermediate and final growth morphologies are described and discussed. Influence of evaporation rate and supersaturation on the mechanism of growth is assessed. It is suggested that under all crystallization conditions, borax crystals have dendritic form in the initial stages of growth.
Stoichiometry and point defects in lithium niobate crystals
Authors: Bollmann W. 
Published: January 2007

AbstractInvestigations of the OH− ion incorporation into LiNbO3 crystals and the comparison of calculated and measured densities show that undoped congruent lithium niobate crystals contain Li+ and O− − ion vavancies O and Li+. If really present, stacking faults are of inferior importance. The good agreement of the absorption edges of stoichiometric and of 2.7 mol% MgO containing congruent lithium niobate crystals is explained by the occupance of all oxygen sites within these crystals.
Mode of solidification and strength properties(II). Naphthalene‐benzil binary system
Authors: Bassi P. S. , Sharma N. K. , Sharma M. K. 
Published: January 2007

AbstractThe tensile and compressive strengths of directionally and randomly grown samples of naphthalene, benzil, and their eutectic in the faceted‐faceted benzil‐naphthalene system have been determined. The tensile strength of naphthalene and the eutectic increased significantly on directional solidification. Directional solidification substantially enhanced the compressive strength of the eutetic whes rea decrease in compressiv strength was observed in case of directionally grown naphthalene. In case of benzil, no appreciable change in strength was observed on directional solidification. A comparison between the tensile and compressive strength was made. The compressive strength was 2.5–3.8 times more than the tensile strength of naphthalene, grown randomly, benzil and their eutectic grown randomly and directionally.
Crystal and molecular structure of bis[2‐ethylamino‐4‐n‐propylamino‐6‐methoxy‐1,3,5‐triazine] copper(II) dichloride. 2‐Ethylamino‐4‐n‐propylamino‐6‐methoxy‐1,3,5‐triazine
Authors: Reck G. , Bannier G. , Kircheiss A. , Bauwe R. 
Published: January 2007

AbstractThe title compound crystallizes in the triclinic space group P1 with 2 formula units C27H51Cl2CuN15O3 in the unit cell. The lattice constants are a = 11.298(2), b = 16.024(4), c = 11.977(3) Å, α = 111.64(2), β = 102.59(2), and γ = 94.46(2)°. The crystal structure was determined by the conventional R = 0.147. The complex formation and the conformations of the three independent triazine molecules are discussed.
Ionicity of the chemical bond in AIBIIIC semiconductors
Authors: Neumann H. 
Published: January 2007

AbstractThe Phillips — van Vechten dielectric theory for binary tetrahedral compounds and Levine's extension of this theory to multibond crystals is used to evaluate the bond ionicities in the AIBIIIC chalcopyrite compounds with AI = Cu, Ag from spectroscopic data. In deriving the ionicity of the AI—CVI bond the influence of the noble metal d electrons it taken into account. The results obtained are compared with previous estimations.
Synthesis of analcime‐type zeolite from natural stilbite by hydrothermal method
Authors: Joshi M. S. , Choudhari A. L. , Kanitkar Ravindra 
Published: January 2007

AbstractUsing calcined stilbite, aluminium hydroxide and sodium hydroxide as ingradients, the procedure to synthesize a zeolite by hydrothermal method is described. Studies on characterisation (of crystals grown) by X‐rays and by infrared spectroscopy, and their morphology by a scanning electron microscope are reported. That the crystals grown have cubic symmetry with a = 13.66 Å and that they are analcime type is established. From infrared spectral studies it is confirmed that the crystals are zeolites. Needle, prismatic, and layer crystals obtained are illustrated and described.
The precipitation of barium hydroxoaluminate hydrate powders from sodium hydroxoaluminate solutions: Precipitate phases and precipitation mechanisms
Authors: Packter A. 
Published: January 2007

AbstractBarium hydroxoaluminate hydrates were precipitated from different sodium hydroxoaluminate solutions at 20 °C; CAl varied from 0.1 to 0.5 M and initial Ba/Al2 ratios ( = excess OH/Al ratios) varied from 1 to 7. Precipitate compositions were determined by chemical analysis, infra‐red spectrophotometry and thermal analysis. The compound BaO · Al2O3 · 7 H2O was precipitated at initial Ba/Al2 ratios of one to well above two while the compound 2 BaO · Al2O3 · 5 H2O was only precipitated over a narrow range of concentrations. The compound Ba(OH)2 · 8 H2O was precipitated from solutions of high hydroxide and barium ion concentrations. The ionic equilibria and precipitation mechanisms in different solutions are discussed.
X‐ray investigation of H2‐annealed quartz crystals
Authors: Zaumseil P. 
Published: January 2007

AbstractThis paper investigates the variation of reflection properties of nearly perfect quartz crystals after annealing in H2‐atmosphere. Annealing at 800 °C causes a strong distortion of the lattice structure. Double‐crystal diffractometer measurements show an approximate tenfold increase of the integral reflection coefficient. The reflection properties change homogeneously over the whole crystals.
Crystal and molecular structure of 3β‐hydroxy‐5β‐estr‐8(14)‐en‐17‐one
Authors: Reck G. , Schubert G. , Langbein G. 
Published: January 2007

AbstractThe title compound crystallizes in the orthorhombic space group P212121 with 4 formula units C18H26O2 in the unit cell. The lattice constants are a = 10.356(2) Å, b = 19.743(3) Å, and c = 7.487(1) Å. The structure was solved by direct methods of phases determination and refined by least‐squares calculations to the conventional R = 0.054.The configuration and conformation of the molecule were determined and compared with those of Δ‐8,14‐anhydrodigitoxigenin.
On splitting of dislocations at a reverse motion in germanium single crystals
Authors: Bondarenko I. E. , Farber B. Ya. , Khodos I. I. , Nikitenko V. I. 
Published: January 2007

AbstractThe dislocation dissociation after the reverse motion along a slip plane in Ge single crystals have been investigated. It has been established that the dissociation width as well as the constriction density were independent on the motion direction. The results obtained have been used to clarify the role of the dislocation splitting in the formation of the phenomenon of the dislocation mobility asymmetry.
Structural and thermal properties of Zn2+‐, Cd2+‐, and Hg2+ forms of zeolite X
Authors: Zieliński S. , Sarbak Z. 
Published: January 2007

AbstractThe exchange of Zn2+, Cd2+ and Hg2+ with zeolite NaX has been studied. The influence of the above cations on crystalline structure of zeolite X and its thermal stability has been shown on the grounds of X‐ray diffraction, differential thermal analysis and infrared spectroscopic measurements.
Re‐determination of the temperature of the coherent spinodal curve in an‐Al‐15 at.% Zn alloy by transmission electron microscopic and hardness investigations
Authors: Kroggel R. , Dutkiewicz J. 
Published: January 2007

AbstractThe character of the coarsening of the concentration modulations is studied in an Al‐15 at. % Zn alloy applying TEM investigations (TEM micrographs and diffraction patterns) and hardness measurements in the temperature range from 40 °C to 130 °C. From the TEM investigations the temperature of the coherent spinodal curve is estimated to be (93 ± 7)°C. This value agrees fairly well with the result obtained by means of hardness measurements (kink in the TTT‐curve occurring at about (84 ± 3) °C). The TEM observations of structure revealed in the Ta‐range below the coherent spinodal a periodic structure relevant to spinodal decomposition. The periodicity of modulations is confirmed by electron diffraction patterns where a clear effect of sidebands near the matrix spots is observed.
Spectroscopic analysis of the heat of formation in AIBIIIC compounds
Authors: Neumann H. 
Published: January 2007

AbstractThe spectroscopic model for the heat of formation of tetrahedrally coordinated binary compounds is extended to the ternary chalcopyrite semiconductors. The heats of formation of all AIBIIIC compounds are evaluated and compared with experimental data. Possible reasons for existing discrepancies between theory and experiment are discussed.
Studies on etching behaviour of {101} faces of natural mesolite crystals
Authors: Joshi M. S. , Joshi V. V. , Choudhari A. L. , Kanitkar R. G. 
Published: January 2007

AbstractEtching behaviour of {101} habit faces of natural mesolite crystals is reported. Rectangular, truncated and elliptical etch pits are illustrated, and mechanism of their formation is assessed. Factors influencing kinetics of etching are discussed. From Arrhenius plots activation energy and pre‐exponential factor are computed and reported.
Ionic conductivity studies in KCl–NaCl mixed crystals
Authors: Veeresham P. , Rao U. V. Subba , Babu V. Hari 
Published: January 2007

AbstractSingle crystals of KCl and a few compositions of KCl‐NaCl mixed crystals were grown from melt by Kyropoulos technique. Ionic conductivity measurements have been carried in these crystals in the temperature range 100 to 400 °C. The activation energy for the migration of charge carriers have been calculated from the conductivity‐temperature plots of these crystals and the results obtained were discussed.