bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some remarks on the statistical character of crystal growth
Authors: Malicsko L. 
Published: July 2007

AbstractThe instantaneous growth rate of KBr crystals growing under constant external conditions in a supersaturated aqueous solution and that of fixing salt crystals growing in an under‐cooled melt show statistical fluctuations. According to our experiments the instantaneous growth rate – as a probability variable – may be described with a good approximation by using a Maxwellian probability density function.
Evaporation of Zinc Single Crystals
Authors: Iwanov D. , Nanev Chr. , Kaischew R. 
Published: July 2007

AbstractThe dislocation nature of defects leading to local evaporation of the {0001} face of zinc single crystals is proved. Two kinds of pits appear on the emergence points of dislocations, upon heating the crystals in vacuum, that is, hexagonal ones on screw dislocations and conical ones on edge dislocations (and probably on impurities). Hexagonal pits appeared at the growth points of whiskers upon evaporation. This is in excellent agreement with the assumption that whiskers grow by a screw dislocation mechanism.Deepening and broadening of the pits were studied by interferometry. It was found that the change in profile with time can be described by the equations of Frank's kinematic theory. The same theory was used to calculate the step flux along the basal face of zinc single crystals upon evaporation at 250, 270, and 290°C. The rate of advance of unit steps was determined from the flux and compared with the theoretically expected one. The temperature dependence of this rate made it possible to estimate the vibrational frequency of the atoms in the crystal lattice as well as the evaporation heat of zinc. The reasonable values obtained demonstrate the correctness of the interpretation of the experimental data.
Beiträge zum Ätzen von Galliumarsenid (II) Zur Kinetik der Auflösung von GaAs
Authors: Voigt R. , Neels H. 
Published: July 2007

AbstractUntersucht wird die Kinetik der Auflösung von {111}‐ und {100}‐Ebenen von GaAs in NaClO‐ und HNO3‐Lösungen sowie im HF/CrO3‐Lösungssystem. Dazu werden Auflösungsgeschwindigkeiten bestimmt und mit Hilfe der Arrhenius‐Gleichung w = C · e Aktivierungsenergien und Geschwindigkeitskonstanten angenähert ermittelt. Es ergeben sich Anhaltspunkte für den geschwindigkeitsbestimmenden Schritt (Diffusion ‐ Konvektion, heterogene chemische Reaktion). Bei der Auflösung von GaAs können je nach Art des Mediums (Konzentrationen) Diffusion oder chemische Reaktion geschwindigkeitsbestimmend sein. In manchen Fällen läßt sich aus der Größe der Geschwindigkeitskonstanten das Erscheinen oder Nichterscheinen von Ätzgruben verstehen. Die Auflösungsgeschwindigkeit w für sich allein gestattet keine zuverlässige Aussage über die Wahrscheinlichkeit der Bildung von Ätzgruben.
The Influence of AsCl3 Impurity on Growth Mechanism and Structure Perfection of Autoepitaxial Germanium Films
Authors: Stepanova A. N. , Sheftal N. N. 
Published: July 2007

AbstractThe changes of film morphology and microtwin concentration in these films caused by AsCl3 impurity have been studied. The correlation of growth mechanism and structure perfection of the films has been revealed.
Phasen und Epitaxien in gasnitrierten polykristallinen Fe‐Blechen und einkristallinen Fe‐Folien
Authors: Amthauer G. , Gebhardt M. , Neuhaus A. 
Published: July 2007

AbstractEs wurden die Phasen‐ und Epitaxiebeziehungen nitrierter Eisenbleche und ‐Folien mittels Röntgen‐ und Elektronenbeugungsmethoden untersucht. Dabei wurden die folgenden, in zeitlicher Bildungsfolge aufgeführten Nitrierphasen gefunden: α Fe(N) (als feste Lösung) ‐ Fe4N (γ′‐Phase) ‐ ϵ‐Phasen (mit ϵ‐Fe3N und ϵ‐Fe2N) ‐m ζ‐Fe2N.Alle genannten Nitrierphasen gehen, laufende N‐Zufuhr vorausgesetzt. durch epitaxisch initiierte Gitterumbaureaktionen auseinander hervor (= Topotaxie).Es konnten epitaxische Verwachsungen aller in der obigen Bildungsfolge benachbarten Fe‐Nitride miteinander und über Epitaxiekette auch mit αFe nachgewiesen werden und zwar: αFe mit Fe4N(γ′); Fe4N(γ′); mit ϵ‐Fe3N; ϵ‐Fe3N mit ϵ‐Fe2N und ϵ‐Fe2N mit ζ‐Fe2N. Alle zugehörigen Verwachsungsgesetze konnten festgelegt werden. Von besonderer Aussagekraft erwiesen sich hierbei nitrierte Fe‐Einkristallfolien von ≈600 Å Dicke, die durch Vakuumaufdampfung auf (001)‐NaCl bei 475°C gezüchtet worden waren.
Short range order parameters for ternary zincblende substitutional solid solutions
Authors: Brühl H. G. , Schmidt W. 
Published: July 2007

AbstractThe determination of Warren's short range order parameters (pair correlations) for substitutional A1‐xBxC‐type solid solutions by means of diffuse X‐ray scattering is described. The relations obtained are applied to the diffuse X‐ray scattering of Ga0.16Al0.84As solid solutions being under different thermal treatment.
Ergebnisse bei der Darstellung von GaAs‐Einkristallen
Authors: Schulz M. , Schaefer H. , Seifert M. , Heckert H. 
Published: July 2007

AbstractEs wird über Arbeiten zur Züchtung von 〈111〉 und 〈100〉 orientierten GaAs‐Einkristallen nach der Czochralski‐Technik mit Abdeckschmelze berichtet. Dargestellt werden Versuchsergebnisse zur Kristallperfektion und zur Dotierung. Für Zinn‐und Tellur‐dotierte GaAs‐Einkristalle werden Zusammenhänge zwischen eingesetztem Dotierungsmaterial und den Kristalleigenschaften experimentell untersucht und diskutiert. Der bei den Untersuchungen ermittelte Verteilungskoeffizient für Sn in GaAs wird mit früher veröffentlichten Werten verglichen. Des weiteren werden Ergebnisse über die Homogenität hinsichtlich der Dotierung und der Perfektion dargestellt.
Colour centre formation in corundum doped with divalent ions
Authors: Kvapil Jiři , Perner B. , Súlovský J. , Kvapil Jos. 
Published: July 2007

AbstractThe colour changes of corundum crystals annealed in hydrogen, oxygen and argon, and exposed to an UV irradiation is described. The comparison of samples doped with Be, Mg, or Fe is given. The change from pink colour to brown of rubies as well as the yellow colour of sapphires is attributed to the O− centre formation which causes an increase of the absorption between 400 to 480 nm.
Study on a simple model of recrystallization of large crystals
Authors: Skřivánek J. , Žáček S. , Vacek V. 
Published: July 2007

AbstractIn this paper a simple model of recrystallization is presented for crystallization of larger crystals than such ones, for which the explanation of Ostwald ripening can hold. Equations describing the particle size distribution are formulated and solved for a special case. The results obtained are in a qualitative agreement with so far observed facts.
Röntgenographische Bestimmung von Gitterdefekten in Magnetiten
Authors: Nestler C.‐G. , Kämpfe B. , Faust A. , Lange D. 
Published: July 2007

AbstractVon unterschiedlichen Magnetiten wurde das Verhältnis Fe2+:Fe3+ chemisch bestimmt und Röntgenbeugungsuntersuchungen wurden durchgeführt. – Die Ergebnisse zeigen, daß alle untersuchten Magnetite in Wirklichkeit Mischkristalle des Systems Magnetit: Maghaemit sind. Mit steigendem Fe3+‐Anteil wurden lokale Inhomogenitäten des Fe2+:Fe3+‐Verhältnisses festgestellt.
Lang method applied to investigation of Al single crystal initial structure and of its effect on the eventual development of plastic strain
Authors: Novikova I. G. , Pustovalov V. V. , Startsev V. I. 
Published: July 2007

AbstractThe land method was used to study the structure of Al single crystals (99.9997% pure) grown from the melt, the thermal stability and the character of changes in different subgrain structures during work hardening. The method has proved to permit observation of slip development both in the early strain region (where occurs “levelling” of the structure of the bulk under strain), and during concert dislocation movement in specific slip planes up to large strains at 4.2°K.
Surface and contact properties of GaN produced from GaAs
Authors: Nieke H. , Rennert K. J. , Thoma A. 
Published: July 2007

AbstractSamples of some thickness and extent showed fine cracks on the brink already after oxidization in Ga2O3 which became more distinctive after nitriding into GaN. Current‐voltage characteristics were recorded from different long nitrided samples with contacts of In, Sn, Sb, and Te. The long nitrided samples had a lower resistance. Some of the samples showed hysteresis effects with characteristics similar to varistors.
Zum Zusammenhang von Verfärbungserscheinungen und Gitterdeformationen in synthetischen Quarzeinkristallen
Authors: Härtwig J. , Dietz R. 
Published: July 2007

AbstractSynthetische Quarzeinkristalle mit Rauchverfärbungsstreifen senkrecht zur Wachstumsrichtung zeigen Maxima der reflektierten Röntgenstrahlung (Reflex (0003)) an Stellen, an denen sich die Absorption im optischen Bereich stark ändert. Nachweisbare Komponenten des Verschiebungsvektors liegen parallel zur Wachstumsrichtung. In Bereichen mit starker Verfärbung ist das Gitter gedehnt.
Investigation of a new LPE method of obtaining AlGaAs heterostructures
Authors: Alferov Zh. I. , Andryev V. M. , Konnikov S. G. , Larionov V. R. , Pushny B. V. 
Published: July 2007

AbstractA more detailed description of some peculiarities of the LPE method published by ALFEROV et al. (1974, 1975) for obtaining multilayer AIIIBV heterostructures and more precise details of the boat construction are given. A particular attention is paid to intermediate transient layers.
Zur Gleichgewichts‐ und Wachstumsform von β‐Kupferphthalocyanin‐Einkristallen
Authors: Kersten F. , Hamann C. 
Published: July 2007

AbstractMit der Methode der PBC‐Vektoren von HARTMAN und PERDOK wird die Gleichgewichtsform von β‐Kupferphthalocyanin‐Einkristallen bestimmt und mit der experimentell ermittelten Wachstumsform aus der Gasphase gezüchteter Kristalle verglichen. Es zeigt sich prinzipielle Übereinstimmung. Die Kristalle sind von nadelförmigem Habitus, die Tracht wird durch die Formen {001}, {201}, {100}, {101} und {110} gebildet. Das Längen–Breiten‐Verhältnis der Kristalle läßt sich durch die Variierung des Inertgasdruckes beeinflussen. Diese Abhängigkeit wird auf die Diffusion des Nährstoffdampfes zurückgeführt.
Zur Röntgenbeugung an kleinen kohärenten Kristallbereichen
Authors: Berger H. 
Published: July 2007

AbstractFür kohärente Einkristalle mit sehr geringen Abmessungen werden Beziehungen für die Winkelintervalle der einfallenden und reflektierten Röntgenstrahlen im Beugungsfall abgeleitet. Im Fall einer dünnen Schicht ergeben sich nach der kinematischen Beugungstheorie explizite Ausdrücke, die sich auch als Grenzfall aus den Beziehungen der dynamischen Theorie herleiten lassen. Das Verhalten der Strahlen ist dabei völlig analog zum Beugungsgeschehen an großen perfekten Einkristallen. Für einen isometrischen kleinen Kristall sind die quantitativen Zusammenhänge von der konkreten experimentellen Anordnung abhängig. Die grundsätzlichen diffraktometrischen Meßmöglichkeiten für diese Winkelintervalle der Beugung werden betrachtet und hinsichtlich ihres Informationsgehaltes verglichen. Für einige praktisch wichtige Anwendungsbeispiele diffraktometrischer Untersuchungen werden die Konsequenzen diskutiert, die sich bei Berücksichtigung der Kohärenzlängenbeiträge ergeben. Dabei wird speziell die Möglichkeit abgeschätzt, einen solchen Beitrag durch Registrierung der Rockingkurve bei festem Winkel 2⊖ experimentell zu ermitteln.
Effect of CuCl2 · 2 H2O additive in ethanol on dissolution and selective etching behaviour of CsI crystals
Authors: Sangwal K. , Urusovskaya A. A. , Smirnov A. E. 
Published: July 2007

Abstract{100} faces of Kyropoulos grown CsI crystals had undergone a selective etching, and CsI spheres of ∼ 10 mm in diameter were subjected to dissolution at room temperature for 10 hrs. The results are: pure ethanol does not bring about any anisotropy in dissolution, addition of CuCl2 · 2 H2O leads to an anisotropy in dissolution of CsI, change in CuCl2 · 2 H2O concentration changes etch pit morphology, whereas the dissolution form does not depend on additive concentration. With increasing CuCl2 · 2 H2O etching rates at first increase, later decrease, dissolution rates linearly increase.
Zur Bestimmung der Kristallitgrößenverteilung von Metallen auf Katalysatorträgern aus Röntgenweitwinkelmessungen (I). Ermittlung primärer Verteilungskenngrößen aus Linienprofilen
Authors: Spindler Herbert , Orban Peter , Westphal Bodo 
Published: July 2007

AbstractEs werden die Möglichkeiten zur Bestimmung der Größenverteilungen von Metallkristalliten in Trägerkatalysatoren aus den Profilen von Röntgenweitwinkelinterferenzen untersucht. Dabei erweist sich ein Fourier‐Verfahren als zweckmäßig, das primär die Momente der Sehnenlängenverteilung liefert. Aus den Ergebnissen lassen sich für die Metallkristallite Verteilungsfunktionen ableiten, die mit hoher Genauigkeit die experimentellen Linienprofile wiedergeben.
Correlation between preparation variables and dielectric data of GaN formed by GaAs conversion
Authors: Procházková Olga , Šrobár F. 
Published: July 2007

AbstractPolycrystalline GaN samples were prepared by two‐stage conversion of monocrystalline GaAs. Dependence of material properties on temperature and duration of the nitriding treatment was studied mainly by means of dielectric data taken in the range 0.25… 110MHz. Existence of optimum nitriding temperature, reported by previous workers, was borne out, and an attempt was made at its explanation in the framework of a simple model.
Zur Korrespondenz von Kristallstruktur und Habitus. Bestimmung der Molekülschwerpunkte in organischen Kristallen
Authors: Follner H. 
Published: July 2007

AbstractSchraubenachsen und Gleitspiegelebenen vermindern die morphologische Bedeutung bestimmter Kristallflächen. Es wird gezeigt, daß auch Pseudosymmetrien die Kristalltracht beeinflussen. Bei organischen Kristallen ist es in günstigen Fällen möglich, mit Hilfe „morphologischer Auslöschungstabellen”︁ näherungsweise die Molekülzentren zu bestimmen.
Röntgenografische Untersuchung des Debye‐Waller‐Faktors und der Gitterkonstanten von V3Si‐Pulver im Temperaturbereich von 25 K bis 1000K
Authors: Försterling G. , Hegenbarth E. 
Published: July 2007

AbstractIm Temperaturbereich von 25 K bis 1000 K werden die Temperaturabhängigkeit der integralen Intensität und Braggwinkel der elastisch gestreuten Röntgenstrahlung von V3Si‐Pulver ermittelt. Die gemessenen Intensitäten können durch einen isotropen, quasiharmonischen Debye‐Waller‐Faktor beschrieben werden. Eine anomale Temperaturabhängigkeit im Bereich des martensitischen Phasenüberganges tritt nicht auf. Der lineare thermische Ausdehnungskoeffizient nimmt im Bereich unter 100 K anomal stark mit der Temperatur ab (und hat ein negatives Vorzeichen bei Temperaturen unterhalb 70 K).
On the growth mechanism of sodalite single crystals grown by the hydrothermal method on single crystal seeds coated with informative informative interfacial layers
Authors: Distler G. I. , Kobzareva S. A. , Lobachev A. N. , Melnikov O. K. , Triodina N. S. 
Published: July 2007

AbstractThe growth mechanism of the early formation stages of sodalite single crystals grown by the method of hydrothermal synthesis on single crystal seeds coated with interfacial layers of polycrystalline silver has been studied at an electronmicroscopic scale. Coating with interfacial layers leads to a very weak adhesion between the overgrown single crystal and the surface of the interfacial layer on top of the seed, thus providing a unique possibility of detaching the overgrown single crystals from seeds and investigating the very early crystallization stages by the morphology of the growth surface. In local microregions of seed surfaces coated with interfacial layers discrete particles arise differing from one another in morphology, this being primarily associated with the electrical heterogeneity of seed surfaces. During crystallization, the space between the discrete particles was filled with the hydrothermal solution which represented a liquid interfacial layer exhibiting informative properties occurred under the influence of electrically active elements of the seed surface. At the boundary separating the liquid interfacial layers with particular informative properties from the rest of the solution volume, at early crystallization stages, together with the formation of discrete particles directly on the coated seed surface, growth of a continuous sodalite single crystal took place. The informative properties of seed surfaces, which are regularly modified due to coating with interfacial silver layers, determine the occurrence on local regions of seed surfaces (under appropriate crystallization conditions) of one or the other polymorphous modification: either hexagonal – cancrinite, or cubic – sodalite.
The development of the rolling texture of f.c.c. metals dependent on relative stacking‐fault energy
Authors: Mücklich A. , Tobisch J. , Kleinstück K. 
Published: July 2007

AbstractNeutronographic texture investigations are presented for nickel and Co32Ni – the representatives of f.c.c. metals of very high or extremely low relative stacking‐fault energies, resp., as well as for α‐brasses with zinc concentrations between 1 and 4 atomic percent, which are typical for mean values of γ/Gb. The discussion of the results is based on three‐dimensional distribution functions calculated by series expansion. For the main texture components a higher indexing as usually is assumed what is also due to the orientations of these minor components originating in the mechanical twinning. The origin of additional minor components of additional minor components is attributed to the formation of surface textures and recrystallization phenomena. The texture development at extreme relative stacking‐fault energies is associated with cross slip or microtwinning and partial glide, resp.
Emission von Elektronen hoher Energie bei der Zerstörung verschiedener fester Körper
Authors: Chrustalev Ju. A. , Krotova N. A. 
Published: July 2007

AbstractEs wird der Einfluß der Struktur und der Eigenschaften einer größeren Zahl von Festkörpern auf die Emission von Elektronen hoher Energie bei mechanischer Beanspruchung dargelegt. Die Ursache dieser Feldelektronen‐Emission ist auf die Wirkung von Restlandungen auf der frischgebildeten Oberfläche zurückzuführen, die in den aktiven Zentren zu Feldstärken bis zu 107 V/cm führen.
Temperature distribution in growing semi‐transparent crystals (I). Theory
Authors: Kvapil Jiří , Kubelka J. , Vadura R. 
Published: July 2007

AbstractSimplified analytical and computational solutions of the temperature distribution in crystals grown by Czochralski method including the temperature difference on the liquid/solid interface are given. The model used is based on experiments with oxide crystals with melting points above 2000 K. Computational solution was more extended because it enables to calculate actual temperature distribution with a relatively small error.
Scandium thin films‐structure and electrical resistance (I). A study on films obtained in a vacuum of 10−5 up to 10−6 Torr
Authors: Loboda V. B. , Protsenko I. E. , Yaremenko A. V. 
Published: July 2007

AbstractA structure as well as a specific electrical resistance of scandium films having a various thickness (300 up to 2800 Å) obtained at a condensation rate: w⋍ 1 up to 155 Å/s have been studied in the present work. Depending on condensation conditions in films a hydride ScHx, h.c.p. — Sc, or ScHx + Sc alternatively, is formed, a phase containing a distorted hexagonal lattice evolving into the ScHx over a period of a few hours. The ScHx and h.c.p‐Sc change to Sc2O3 when annealed in a vacuum of 5 · 10−5 Torr at a T ≈ 800°C, while in a vacuum of 3 · 10−8 Torr a change to h.c.p.‐Sc with negligible inclusions of oxidic Sc2O3 particles takes place. Formation of oxide is observed also when heating the films with an electron beam directly in a microscope under vacuum of ∼ 8 · 10−5 Torr. The specific electrical resistance ϱ of the film just after a condensation has taken place is approximatly by an order higher as against the ScHx‐ and h.c.p.‐Sc solid specimens. An irreversible gain in said resistance is observed while holding at a room temperature or annealing in a vacuum of 5 · 10−5 Torr, this being associated with absorption of H2, O2 and, possibly, of water steam, and then with formation of Sc2O3. Annealing in a vacuum of 5 · 10−8 up to 10−7 Torr involves a temperature relationship for ϱ of an intricated nature, this being accounted for by a structure transition as follows:

A diode‐effect diminishing with a temperature rise is observed in annealed films.
Some micro‐disk patterns on calcite
Authors: Desai C. C. 
Published: July 2007

AbstractMicrodisk patterns have been produced on {100} cleavage faces of calcite crystals by etching them in a 5 p.c. citric acid solution at 80°C. It is observed that the disks are of different sizes and are distributed all over the face. The microtopography of the disks studied by interferometry has revealed that they are slight elevations on the surface. Various experiments have been performed on matched cleavage faces of calcite and it has been established that the formation of the microdisks is due to protective action of microbubbles formed on the crystal surface during the process of etching. The implications are discussed.
On the growth of one spherical precipitate in an isotropic infinite matrix
Authors: Simmich O. , Löffler H. 
Published: July 2007

AbstractThe growth of one spherical precipitate in an isotropic infinite matrix is treated solving the diffusion equation of the “stationary solution”, i.e. assuming ∂c/∂t = 0, for the general case that the diffusion constant D depends on concentration c. The influence of the resistance of the interface p = p(R) on the growth is considered, too (R radius of the precipitate). It could be shown that the growth law of the particle R ∼ t1/2 holds even foreach D = D(c) used, but it depends sensitively on p = p(R) applied.
On a delayed dislocation emission from hot hardness indentations
Authors: Brenner B. , Wetzig K. 
Published: July 2007

AbstractThe change of the dislocation arrangements around microindentations after indentation test has been investigated by TEM and etching. The indentations were generated on {100} ‐ surfaces of iron single crystals at temperatures between 800 K and 1000 K. The change of the dislocation structure was found to depend strongly on stress and dislocation density in the deformation field. The deformation field especially acts as a dislocation source operating over long periods. The results suggest that the propagation of emitted dislocations is controlled by dragging of Cottrell‐atmospheres of carbon atoms. Conclusions regarding the hardness‐temperature relation in pure iron are drawn.
Mechanical interaction of point defects and volume defects near curved surfaces
Authors: Michael D. , Michel B. 
Published: July 2007

AbstractThe paper deals with the influence of spherical surfaces of solids upon elastic interaction between two point defects or volume defects in an elastic isotropic medium. Formulae have been derived, taking into account the finite dimensions of the defects. This leads to analytic expressions for the energy terms which remain correct (finite) also in the immediate vicinity of the boundary surface of the solid. Hence, they are more sufficient for further application than it is the case with formulae, based on the concept of singular dilatation centres only. The latter are mostly used for investigations of the bulk material, but they lead to divergent expressions for the interaction energy at the surface. Approximation formulae will be given for practical application.