bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single crystals of barium substituted rare‐earth orthomanganites
Authors: Nevřiva M. , Pollert E. 
Published: January 2007

AbstractThe single crystals from the series of Re1‐xBaxMnO3solid solutions (Re = Pr, Nd) were prepared by the flux growth from the melt containing 0.41 BaO — 0.18 BaF2— 0.41 B2O3. as the flux constituents. The conditions of the growth, in particular the liquidus curves of the relevant pseudobinary systems, were determined by the high‐temperature microscope technique. The prepared crystals were characterized by X‐ray and chemical analysis.
Rotation field and continuity equation for texture evolution
Authors: Wierzbanowski K. , Clement A. 
Published: January 2007

AbstractIn the present paper a quite general approach is proposed for the problem of the formation of the prefered orientations (i.e. of the texture). The rotation field is considered by the present authors as the most general variable which describes completely the texture formation process. The proposed continuity equation transforms immediately the rotation field to the texture function (Orientation distribution function). The presented formatlism is illustrated by a few f.c.c. rolling textures.
Conoscopic optical method of determining liquid crystal low tilt angles
Authors: Komitov L. , Hauck G. , Koswig H. D. 
Published: January 2007

AbstractA simple conoscopic optical method of determining liquid crystal low tilt angles with sufficient accuracy for many practical purposes is described. The similarity between this method and the crystal rotation one is shown. The limits of applicability of the conoscopic optical method are also given.
The influence of OH−‐ions on the mechanical properties in LiF and NaCl single crystals
Authors: Lubenets S. V. , Ostapchuk E. I. , Soifer L. M. , Appel F. , Kaufmann H.‐J. 
Published: January 2007

AbstractAn LiF‐ und NaCl‐Einkristallen wurde der Einfluß der Atmosphäre beim Wachstumsprozeß auf die Verformungseigenschaften untersucht. Die Atmosphären waren Luft oder Vakuum bzw. Argon. Die an Luft gezogenen Kristalle haben in einem breiten Temperaturintervall eine höhere Fließspannung und ein kleineres Aktivierungsvolumen. Außerdem ist die Versetzungsbeweglichkeit geringer. Die Unterschiede entstehen vermutlich durch OH−‐Ionen, die in den an Luft gezogenen Materialien in größerer Konzenration gefunden wurden. Die OH−‐Ionen können selbst Gitterverzerrungen erzeugen bzw. durch die Zusammenlagerung mit den zweiwertigen Kationverunreinigungen bilden. Auf diese Weise erhöht sich die Dichte der thermischen und athermischen Hindernisse für die Versetzungsbewegung.
Characteristic temperature of deformation of crystalline materials
Authors: Trefilov V. I. , Milman Yu. V. , Gridneva I. V. 
Published: January 2007

AbstractUsing the ceoncept of a characteristic deformation temperature, t* (knee temperature), below which the PEIERLS‐NABARRO stress becomes significant, some general regularities have been determined on the influence of temperature upon structural state and mechanical properties of crystalline materials. It is demonstrated that t* represents a natural boundary between the intervals of warm and cold deformation. At the temperature t*, the mechanisms of deformation, fracture, and recovery of properties in annealing vary significantly in the same manner for different crystals.
Induced growth striations in Quartz Crystals
Authors: Bernhardt Hj. , Alter U. 
Published: January 2007

AbstractDue to periodical modulation of the temperature difference between the solution and growing rooms growth striations in quartz crystals have been induced. These induced striations have been found as smoky quartz coloration striations as Al containing material has been used. X‐ray topographic investigations found these growth striations even in the unirradiated quartz crystal.
Liquid‐phase epitaxy of Potassium Niobate
Authors: Khachaturyan O. A. , Madoyan R. S. 
Published: January 2007

AbstractThe possibility of potassium niobate films growing by means of liquid phase epitaxy technique was investigated. The physical and chemical analyses of K2O‐V2O5‐Nb2O5 system were carried out. Corundum wafers with {1¯210} and {0001} orientations served as substrates. The grown films were 10–30 μm thick. The grown heterostructures had a sharp, phase boundary line substrate‐film. Epitaxial layer perfection was investigated by X‐ray and electronographic methods.
Effect of γ‐irradiation on mechanically activated and on non‐activated LiF
Authors: Eifler R.‐J. , Ebert I. , Hennig H.‐P. , Schmidt J. , Kretzschmar U. 
Published: January 2007

AbstractBy means of EPR spectroscopy lattice defects have been investigated, which had been produced in OH− containing LiF by mechanical activation and subsequent irradiation (mainly γ‐irradiation). The structure of irradiation‐induced hydrogen centers shows characteristic differences dependent on the kind of LiF: Hs0 (hydrogen atoms in anion vacancies) are created in mechanically activated LiF powders, whereas Hi0 (hydrogen atoms in interstitial positions) in LiF single crystals. In both the cases also F centers are produced besides other paramagnetic defects. The observed defects can be used for an estimation of the degree of distortion in mechanically activated LiF.
Plasticity of high purity iron single crystals (I) 1. work hardening
Authors: Novák V. , Kadečková S. , Šesták B. , Zárubová N. 
Published: January 2007

AbstractHigh purity iron single crystals were deformed in tension in the temperature range 4.2 to 473 K. Work‐hardening characteristics were determined and the plastic behaviour in dependence on temperature, strain rate and crystal orientation isz discussed. The transition temperature between low‐temperature and intermediate‐temperature deformation regimes was found to be ≅ 250 K, the critical temperature estimated from the temperature dependence of the critical resolved shear stress is ≅ 380 K. A hump on the temperature dependence of the critical resolved shear stress was observed in the vicinity of 250 K. These observations are qualitatively explained by special mobilities of dislocations in b.c.c. lattice.
Crystal growth of PbTe and (Pb, Sn)Te by the bridgman method and by THM
Authors: Gille P. , Mühlberg M. , Parthier L. , Rudolph P. 
Published: January 2007

AbstractSynthesis and growth of PbTe and (Pb, Sn)Te single crystals by the Bridgman method and by the Travelling Heater Method (THM) from Te‐rich solutions are described. It is to be seen from comparative investigations that seeded THM growth reproducibly provides oriented single‐crystalline ingots free of low‐angle grain boundaries and with etch pit densities of 8–12 × 104 cm−2. All the materials were p‐type with carrier concentrations from 1 to 2 × 1018 cm−3.
Process characteristics and parameters of Anodic Oxidation by spark discharge (ANOF)
Authors: Krysmann W. , Kurze P. , Dittrich K.‐H. , Schneider H. G. 
Published: January 2007

AbstractProcess characteristics and parameters of ANOF as well as that special logarithmic relation of the layer formation parameters which is valid for the spark region are discussed. By calorimetric investigation it can be shown that the greatest share of electric energy will be transformed to heat and that the current quantity of ≈ 1.1.A · s · cm−2 is characteristic for the incubation period before spark discharge during the gas — solid reaction of aluminium coating.
The fracture behaviour of Chromium‐ and Titanium‐doped sapphire monocrystals
Authors: Müller B. 
Published: January 2007

AbstractThe influence of chromium and titanium on the fracture behaviour of sapphire crystals was analysed by means of crack indentation pattern, and the critical stress intensity factors for the easiest spalling planes of the sapphire were measured from the crack lengths at the indents. Together with information on the room temperature plasticity of sapphire the results allow conclusions on the influence of the dopants on crystallographic and glass‐like fracture features, respectively.
Effective oxygen charge in SiO2 and its dependence on the bond angle of oxygen
Authors: Geisser C. H. , Hübner K. 
Published: January 2007

AbstractIt is not clear until now, whether the oxygen bond angle and the effective oxygen charge in SiO2 are correlated or not. This paper reviews various theoretical and experimental facts concerning some special features of the atomic structure and of electronic properties of SiO2. They lead to contrary conclusions about the correlation between the effective oxygen charge and the oxygen bond angle in distinct SiO2 forms. Results basing on quantum‐chemical investigations are compared with conclusions drawn from the dielectric theory and from tight‐binding calculations of electronic states. A critical valuation of the different methods with special consideration of solid‐state investigations yield the result that the effective oxygen charge increases with increasing bond angle.
Crystal growth rate from the AgNO3‐Dimethylsulfoxide melt
Authors: Pacák P. , Špalková H. 
Published: January 2007

AbstractThe growth rate of AgNO3·DMSO crystals from its melt and concentrated aqueous solutions was studied in the dependence on supercooling (ΔT = 0.5–65°C) by microscopic technique. The experimental results were analyzed according to the formalism proposed for describing growth kinetics from melts.
The growth of oxide precipitates during intrinsic getter formation
Authors: Pekarev A. I. , Nemtsev G. Z. 
Published: January 2007

AbstractThe simulation of the process of the intrinsic oxide getter (IOG) formation in terms of the precipitate growth depending on oxygen concentration in single‐crystal silicon and the nucleation temperature is done. The conditions of annealing at continuously increasing temperature and those of two‐stage and isothermal anneals are calculated. The possibility of intrinsic getter formation in Si with the boron concentration of 1.1015 and that of oxygen 6–8.1017 cm−3 during a two‐step annealing is experimentally evaluated (according to the density of microdefects). The temperature of the most rapid growth of IOG predicted due to the simulation is defined.
Effective distribution coefficient of Si in Fe—Si alloys at floating zone melting
Authors: Vaněk P. 
Published: January 2007

AbstractEffective distribution coefficients of silicon in Fe—Si alloys with 1.0–12.1 at.% Si in floating zone melting at various solidification rates were determined. The dependence of kef on the solidification rate was compared with the Burton‐Prim‐Slichter equation. Effective distribution coefficients extrapolated to a zero solidification rate were compared with equilibrium distribution coefficients taken from the equilibrium phase diagram of Fe—Si.
The Proton‐induced kossel effect and its application to crystallographic studies
Authors: Geist V. , Ascheron C. 
Published: January 2007

AbstractA survey is given of the characteristic features of the proton‐induced Kossel effect and its use for crystallographic investigations of semiconductor materials. The excitation of the characteristic X‐rays was performed with protons in the energy range 0.5–1.5 MeV. Mainly long‐wave X‐radiation was used because of the high X‐ray yields and large Bragg angles also for reflections with low indices. The use of the effect for lattice parameter determinations, the identification of polar surfaces and the detection of tetragonal distortions is described. In this connection the advantage of simultaneously recording Kossel reflection and blocking pattern is also demonstrated. The different behaviour of the observed P—Kα‐ and Ga—Kα‐reflections in response to lattice damage is pointed out.
Electrical properties of Al‐CeO2‐Al thin film capacitor structures
Authors: Chandra Shekar M. , Hari Babu V. 
Published: January 2007

AbstractCerium Oxide films were prepared by vacuum thermal evaporation from tantalum boat in a conventional vacuum coating unit. Current‐voltage characteristics were studied for different film thicknesses. The breakdown voltage (VB) and dielectric field strength (EB) were calculated. It is found that the breakdown voltage increases and dielectric field strength decreases as the thickness of the film increases. The applicability of Forlani‐Minnaja relation is discussed. Current‐voltage characteristics were also drawn at different temperatures and breakdown voltages were calculated. The breakdown voltage decreases as the temperature of the structure increases but the variation is nonlinear. The variation of current density with temperature was studied and the activation energy for the migration of charge carriers was calculated and it is about 0.52 ev. The results were discussed.
Thermoluminescence of ZnO:Cu, La under UV and γ‐ray irradiation
Authors: Diwan D. , Bhushan S. , Kathuria S. P. 
Published: January 2007

AbstractThermoluminescence (TL) glow curves of ZnO: Cu, La have been recorded under UV and γ‐ray irradiations. These consist of a pronounced peak at 600°K alongwith some sharp transitions. The higher temperature peak has been studied by a number of methods namely heating rate, initial rise, isothermal decay and peak shape methods and activation energy (E), escape frequency factor (s) and the order of kinetics (l) have been determined and their nature has been discussed. E is found to be ∼1.63 eV and the order of kinetics l = 2 for this peak.
Formation of iron carbonitride and iron carbide phases during nitrogen ion implantation
Authors: Rauschenbach Bernd , Hohmuth Karl 
Published: January 2007

AbstractPolycrystalline iron is implanted with nitrogen ions with high doses at room temperature. During nitrogen ion implantation iron is doped with carbon by recoil implantation. The formation and the transformation of iron carbonitrides and iron carbides are investigated by high‐voltage electron microscopy. The implantation‐induced phase formation of iron carbonitride phases are discussed.
Peculiarities of the cross‐section in chemically prepared SnO2‐ and SnO2:Sb layers
Authors: Dogil B. , Froissart F. , Horodecki A. J. , Precht W. 
Published: January 2007

AbstractLayers of pure as well as Sb‐doped tin dioxide have been prepared using intentionally simple modification of CVD technique. By electron microscopy of cross‐section, at least two sublayers have been observed in samples of thickness of a few micrometers in both of the cases. Their formation is thought to be associated with small perturbation of thermodynamical equilibrium arising due to the layer growth.
The effect of B2O3 on the solubility of (YSmLuCa)3(FeGe)5O12 garnet in PbO‐B2O3 flux
Authors: Nitsch K. , Bok J. , Kučera M. , Petrík S. , Pištora J. , Višňovský Š. 
Published: January 2007

AbstractThe paper deals with the solubility of (YSmLuCa)3 (FeGe)5O12 garnet in PbO—B2O3 flux. An anionic model explaining the effect of B2O3 on the solubility of rare earth garnet is suggested. This model is based on the assumption that PbO in the melted mixture of PbO, B2O3, Fe2O3, R2O3, CaO, GeO2 dissociates into Pb2+ and O2−. The oxygen anions react with the other oxides under the formation of BO33−, FeO33−, RO69−, CaO22− and GeO32− anions, until the equilibrium is established. The garnet is dissociated into the anions mentioned above. The validity of the model is verified by an agreement of the experimentally determined saturation temperatures of the melts for LPE of garnet layers with the Arrhenius‐type expression of the solubility product of garnet
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where xi denotes the equilibrium concentrations of the anions in the melt and x° is the Ge content of the garnet film.
X‐ray investigations of BaLaGa3O7 single crystals
Authors: Przedmojski J. , Pura B. , Piekarczyk W. , Berkowski M. 
Published: January 2007

AbstractX‐ray investigations have been carried out on single crystals of BaLaGa3O7. Debye temperature as well as thermal expansion coefficients were determined, and values of which are respectively
The role of impurity precipitates on microhardness of NaCl:Ba2+ crystals
Authors: Narasimha Reddy K. , Lakshmipathi Rao M. 
Published: January 2007

AbstractMicrohardness studies of NaCl crystals doped with different concentrations of barium have been carried out both in the as grown state and after quenching them from various elevated temperatures. In heavily doped NaCl crystals visible precipitates are observed and after quenching these precipitates are dissolved partially. The effect of these precipitates on microhardness is discussed.
Nucleation and growth of some solution‐grown crystals in gel media: Visualization by interferometric holography
Authors: Lefaucheux F. , Robert M. C. , Bernard Y. , Gits S. 
Published: January 2007

AbstractHolographic interferometry has been applied to the study of mass transfer induced by nucleation and growth in gel media. Real time obsrvations were made on growth of insoluble (CaHPO4, 2 H2O) and soluble (KDP) materials.
Some transport measurements of WSe2‐x single crystals
Authors: Agarwal M. K. , Jani A. R. , Kshtriya J. D. , Vashi M. N. , Garg P. K. 
Published: January 2007

AbstractElectrical resistivity and its anisotropy, thermoelectric power and temperature coefficient of resistivity of WSe2‐x crystals have been measured (0.01 ≦x≦ 0.1) in the temperature range 300–448 K. Variations of these physical properties with respect to temperature and composition have been examined. The observed results are discussed in the light of semiconducting nature of the material.
VSZ‐5 Zeolite crystals — hydrothermal synthesis and characterization
Authors: Joshi M. S. , Mohan Rao P. , Choudhari A. L. , Kanitkar Ravindra G. 
Published: January 2007

AbstractProcedure for hydrothermal synthesis of zeolite crystals, named here as VSZ‐5, is described. Needles, prismatic and prismatic pyramidal habits of these crystals are illustrated and described. By Mössbauer spectroscopy it is established that iron is leached out from the steel liner used. Phosphorus is introduced in the zeolite lattice. Surface structures on the crystals are illustrated.
Structure investigations of the Ge‐GeO2 system by high‐resolution electron microscopy
Authors: Werner P. , Rozhanski N. V. , Arslambecov A. V. , Heydenreich J. 
Published: January 2007

AbstractThe crystal structure of thermally oxidized Ge was investigated by high‐resolution electron microscopy (HREM), mainly the interface Ge/oxide. Under special conditions the reaction Ge + O2 → GeO2 which takes place at (111) surface planes leads to suitable thin crystal regions. The GeO2 occurs normally as amorphous films on the crystal surface. Furthermore, hexagonal GeO2 can grow at the interface Ge/oxide by a topotaxial reaction; the orientation relation between these two lattices was ascertained. Intensive electron irradiation was used to initiate and to observe structure changes in boundary regions.
Direction change of dislocations on passing a growth sector boundary in quartz crystals
Authors: Alter U. , Voigt G. 
Published: January 2007

AbstractThe behaviour of dislocations in quartz crystals changing their direction while passing from one growth sector into another where studied with X‐ray topography. The investigations were performed on crystals which had been grown in c direction from seeds cut from different growth sectors. The dislocations are newly arranged according to KLAPPER's theory, when they enter a growth sector with a different direction.
Irradiation‐induced change of valence of Cr3+ ions doped in alkali sulphates
Authors: Alybakov A. A. , Gubanova V. A. , Kudabaev K. , Sharsheev K. 
Published: January 2007

AbstractIt is shown by means of investigation of both optical absorption spectra and Roentgen K‐lines of chromium doped in LiKSO4, LiNaSO4, and Li2SO4 · H2O crystals, that X‐irradiation results in change of the impurity charge in a following way: Cr3+ + h → Cr4, Cr4+ + h → Cr5+.
Production of sapphire tubes for high‐pressure sodium lamps using the stepanov method at high rates of growth
Authors: Borodin V. A. , Steriopolo T. A. , Tatarchenko V. A. , Chernyshova L. I. , Yalovets T. N. 
Published: January 2007

AbstractThe process of the Stepanov growth of sapphire tubes is studied at the growth rates up to 20 mm · min−1 in a Mo crucible with graphite succeptor. It is established that the main factor preventing the production of high‐quality samples is contamination of the melt due to the gas transport reactions the growth chamber atmosphere and formation of oversaturated carbon solid solution in the Al2O3 matrix. The decomposition of this solid solution gives rise to the second‐phase‐particle precipitations. The production of highquality sapphire tubes at the growth rates up to 20 mm · min−1 is possible with a careful elimination of water vapours and oxygen from the growth chamber atmosphere.
Polymorphism and aging in terephthalic acid
Authors: Saska Michael , Myerson Allan S. 
Published: January 2007

AbstractThe role of the polymorphic transformation was investigated by X‐Ray diffraction in the habit modification process of terephthalic acid reported earlier (Gaines, Myerson). Contrary to the expectations it was found that only one of the two polymorphs described in the literature (Bailey, Brown) was present. Using an interatomic function derived (Derissen, Smit) to approximate the crystallographic properties of this class of organic acids, we calculated the lattice energies of the two proposed polymorphs of terephthalic acid. These were found to be 41.02 and 39.99 kcal/mole for the polymorphs I and II, respectively. The heat of transition calculated (1.03 kcal/mole) is small enough to be overcome by an increase of the enthropy term and the polymorphic transition is realizable.
Nucleation and precipitation in an Al‐Si(1 at.%) alloy investigated by positron annihilation
Authors: Krause R. , Dlubek G. , Brümmer O. , Skladnikiewitz S. , Daut H. 
Published: January 2007

AbstractIn AlSi alloys incoherent precipitates containing the pure solute element and having diamond cubic crystal structure are formed during a post‐quench annealing without formation of any metastable phase (Mondolfo). Quenched‐in vacancies have a strong effect on rates of precipitation from solid solution by transporting Si atoms as well as by their influence on the nucleation process. One suggestion is the precipitate formation by homogeneous nucleation of small Si clusters rich of vacancies (see for instance Beller). Another picture is the heterogeneous precipitation.Positron annihilation can be expected to be very useful in studying small precipitate nuclei and the role of vacancies in the nucleation process. Positrons provide information of the concentration, configuration and internal structure of such lattice defects in solids, like dislocations, vacancies and vacancy‐clusters (Hautojärvi). The method is also very fruitful in studying small coherent precipitations (Dlubek et al. 1981). The aim of the present work is to study the nucleation and precipitation processes going on in an AlSi (1 at.%) alloy between room temperature and 300 °C by measuring the positron lifetime spectra.The spectra of pure, well annealed metals without any localisation sites are one‐component exponential decay spectra. The time constant is called mean positron lifetime (in Al:τ = 165 ps). It is a measure of the reciprocal electron density. If positrons are localized at a certain kind of traps (such like vacancies or dislocations) a second exponential decay component will appear. The lifetime of the second, longer component is characteristic of the kind of the trap, the intensity of this component is connected with the trap density. It is for instance possible to distinguish clearly between monovacancies, divacancies and small vacancy clusters on the basis of the τ2 values (Hautojärvi).The investigated AlSi(1 at.%) alloy was prepared from 4 N materials. After homogeneisation at 560 °C for some hours the samples were quenched into water at room temperature. Isochronal annealing treatment of samples was performed in 20 K steps (0.5 hours). After each annealing step the samples were slowly cooled down from the annealing temperature to room temperature within 5 minutes. Figure 1 shows the results of the isochronal annealing experiment.