bluuebunny/crossref_metadata_2025 huggingface dataset:
The precipitation of transition metal oxalate powders from aqueous solution. Crystal numbers and final sizes
Authors: Packter A.
Published: July 2007

The precipitation of manganous, ferrous, cobalt, nickel and copper oxalate hydrates was studied from equivalent solutions of concentrations from 0.001 to 0.3 M at pHs 7 to 6, by optical microscopy and other methods. Crystals growth started after induction periods: the precipitations were heterogeneously nucleated at low supersaturations and homogeneously nucleated at medium to high supersaturations. The crystal numbers of the final precipitates depended on the number of nuclei (and crystallites) formed during the induction periods. At medium to high supersaturations, crystal numbers increased with increasing initial metal oxalate complex ion concentrations according to the relation. N = N1Cmoxβ, where β was 5. The N values increased in the order Mn ≪ Fe < Co < < Ni < Cu.

The final crystal lengths, in this range, then decreased with increasing metal oxalate complex ion concentrations according to the relation lfin = l1/Cmoxγ, where γ was 1.3. For precipitations from solution of any concentration, smaller crystals were generally obtained in the precipitates of the metal oxalate of lower solubility; nickel oxalate precipitations were the exception to this.
X‐ray diffraction topography and diffuse scattering techniques applied to study the defect structure of plastically deformed al single crystals
Authors: Braude I. S. , Novikova I. G. , Startsev V. I.
Published: July 2007

X‐ray diffraction topography and diffuse scattering techniques were used to study the defect structure formation of plastically deformed Al single crystals. The investigated X‐ray scattering has been found out materially to depend upon the character of the dislocation structure (upon the geometry of the dislocation distribution). This dependence is manifested in different distribution of the intensity and in the changed form of the isointensity curves of diffuse and regular (Laue) reflections. In spite of the fact that the distribution of the internal stresses acting in different glide systems under conditions of uniaxial stretching is of complicated character, it is possible to trace the development of the glide process in the body of a sample and to obtain satisfactory interference patterns both of regular reflexions (on topograms) and of diffuse ones (on Laue photographs) up to severe deformations of a crystal at 300, 4.2, and 1.6 K.

The following diffuse effects connected with structural changes in deformed crystals have been ascertained on the X‐ray photographs:

—diffuse regions are elongated in the reciprocal lattice space along the glide directions or other crystallographic directions;

—these diffuse regions are split into separate areas along the directions of the said elongations;

—the diffuse regions are changed in length: the diffuse reflexes are diffused or condensed;

—the diffuse scattering isointensity curves are “zigzag”‐shaped.
Zum Temperaturverhalten von Anpassungsversetzungen im gerichtet erstarrten NiAlCr‐Eutektikum
Authors: Zies G. , Völlmar S.
Published: July 2007

Im gerichtet erstarrten NiAl–Cr‐Eutektikum wird ein bestimmter Betrag der Fehlpassung zwischen den Chromstäben und der NiAl‐Matrix durch regelmäßige Anordnungen von Anpassungsversetzungen abgebaut. In vorliegender Arbeit wurde das Verhalten dieser Versetzungsnetzwerke in einem größeren Temperaturintervall untersucht. Die Wärmebehandlung wurde einmal während der transmissionselektronenmikroskopischen Beobachtung dünner Folien (bis 700°C) zum anderen an kompakten Proben (bei 800° und 900°C) vorgenommen. Obwohl sich die Fehlpassung mit der Temperatur infolge der unterschiedlichen thermischen Ausdehnungskoeffizienten der beiden Phasen verändert, bleiben die beobachteten Versetzungsnetzwerke stabil.
Dotierung dünner VO2‐Schichten
Authors: Ufert K.‐D. , Steenbeck K. , Steinbeiss R.
Published: July 2007

Es wird die Herstellung von VO2‐Schichten mit W‐ bzw. Al‐Dotierung mit der reaktiven Gleichstrom‐Sputtertechnik und mit nachfolgender Temperaturbehandlung beschrieben. Das Widerstands‐Temperatur‐Verhalten der Schichten wurde in Abhängigkeit von der Dotierungskonzentration und der Kristallitstruktur untersucht. Die Kristallitgröße hat wesentlichen Einfluß auf die elektrische Wirksamkeit der Dotierung.
Homogenitätsuntersuchungen und Bestimmung der molaren Konzentration x an CdxHg1–xTe mit Hilfe der Elektronenstrahlmikrosonde
Authors: Dittmar Günter
Published: July 2007

Der Halbleiter CdxHg1–xTe dient als Ausgangsmaterial für die Herstellung von Infrarotdetektoren mit hoher Detektivität und geringer Zeitkonstante. Für die rationelle Fertigung der Detektoren werden CdxHg1–xTe‐Einkristalle benötigt. Die Einkristalle dürfen keine Ausscheidungen enthalten und sollen eine gleichmäßige molare Konzentration x besitzen. Eine Elektronenstrahl‐Mikrosonde erfüllt alle Anforderungen, die an das Meßverfahren zur Überprüfung der Homogenität der CdxHg1–xTe‐Kristalle gestellt werden. — Ergebnisse qualitativer und quantitativer Untersuchungen im mikroskopischen und makroskopischen Bereich werden dargestellt. Typische Störungen des Gitters werden mit der qualitativen Elektronenstrahl‐Mikroanalyse erkannt. Die quantitative Analyse wurde mit Standardproben durchgeführt. Das Verfahren zur Bestimmung der molaren Konzentration x der Standardproben wird beschrieben.
Microplasticity of CsI crystals
Authors: Sizova N. L. , Urusovskaya A. A.
Published: July 2007

The study of the mechanisms of plastic deformation of CsI crystals has found the participation of not only the main {110} 〈100〉 slip system but also of the secondary one {110} 〈110〉. Besides that, production and motion of point defects (or small prismatic loops) take place. The gliding on secondary slip system and the deformation accounted for by the generation and motion of point defects is facilitated at low temperatures and high deformation rates. The character of the motion and multiplication of dislocations in the main slip system is investigated. From the temperature and stress dependence of the mobility of isolated dislocations quantitative data on the thermally activated motion of edge dislocations on the main slip system have been obtained. It is shown that, as in the case of other alkali halides, the thermally activated motion of edge dislocations in CsI crystals on {110} 〈100〉 system is limited by their interaction with local obstacles.
Untersuchungen über die thermische Umlagerung von Metallphthalocyaninen mit der Differentialthermoanalyse
Authors: Starke M. , Strehle C.
Published: July 2007

Es wird die α‐β‐Umwandlung bei Kupferphthalocyanin und bei Mischkristallen aus Kupferphthalocyanin und Vanadylphthalocyanin mit Hilfe der Differentialthermoanalyse untersucht. Die Messung der Abhängigkeit der Temperatur des Peakmaximums von der Aufheizrate führt zu Aussagen über die Aktivierungsenergie und den Frequenzfaktor, die Ausmessung der Peakfläche zu Angaben über die Umwandlungswärme.
Zur elastischen Wechselwirkung von Punktdefekten und Einschlüssen in der Nähe von Festkörperoberflächen
Authors: Michel Bernd
Published: July 2007

Bei der Berechnung der Wechselwirkungsenergie von Punktdefekten und Einschlüssen in Festkörpern wird der Einfluß der Oberfläche gewöhnlich vernachlässigt. Aber in unmittelbarer Nachbarschaft von Festkörperoberflächen sind die Deformationen um die Defekte mit einem bestimmten zusätzlichen Beitrag zur Gesamtenergie verbunden, der mit den Methoden der Kontinuumsmechanik berechnet werden kann. Das Medium wird dabei als homogen und isotrop vorausgesetzt. Es wird ein analytischer Ausdruck für die Wechselwirkungsenergie zweier sphärischer Einschlüsse in der Nähe einer Halbraumbegrenzung abgeleitet. Die Ergebnisse zeigen, daß sowohl Anziehung als auch Abstoßung der Defekte in Abhängigkeit von rein geometrischen Parametern auftreten kann.
Ein Beitrag zur Ausscheidungsfolge in AlZnMg‐Legierungen
Authors: Kroggel R. , Löffler H. , Korngiebel E. , Zoch G.
Published: July 2007

Mittels Röntgenkleinwinkelstreu‐, Mikrohärte‐ und dilatometrischen Untersuchungen wurde das Entmischungsverhalten von AlZn(6)Mg(X)‐ und AlZn(4,5)Mg(X)‐Legierungen studiert. Es wurde gefunden, daß a) das bei den binären AlZn‐Legierungen bei etwa 31 Å auftretenden Minimum der Mikrohärte durch den Zusatz von Mg nicht wesentlich verschoben wird, dagegen, b) das in AlZn bei etwa 49 Å liegende Maximum mit zunehmenden Mg‐Gehalt zu niedrigeren Werten der Guinier‐Radien rückt und c) wahrscheinlich die Bildung der teilkohärenten η′‐Phase über elliptische GPZ vor sich geht. — Aus den Befunden werden Folgerungen gezogen.
Bestimmung von Diffusionskoeffizienten aus der Röntgen‐Kleinwinkelstreuung und Lichtstreuung von Gläsern
Authors: Kranold R. , Fink H.‐P. , Göcke W. , Becherer G.
Published: July 2007

Es wird gezeigt, wie aus der Röntgen‐Kleinwinkelstreuung und Lichtstreuung phasengetrennter Gläser auf die Art des Entmischungsvorgangs geschlossen werden kann. Für diffusionsbestimmtes Keimwachstum und spinodale Entmischung werden Methoden aufgezeigt, die es gestatten, die diese Entmischungsvorgänge bestimmenden Diffusionskoeffizienten aus den Ergebnissen der Beugungsexperimente zu bestimmen. Die entwickelten Methoden werden an drei Gläsern demonstriert.
Analytische Untersuchungen zum Small‐Scale‐Yielding‐Problem
Authors: Uhlmann W.
Published: July 2007

Zur asymptotischen Lösung von HUTCHINSON für das small scale yielding problem bei Potenzverfestigung wird mittels einer Störungsrechnung die Zweite Näherung angegeben. Der verwendete Störungsmechanismus gestattet es auch, höhere Näherungen sukzessive zu bestimmen. Dazu wird ein Ausdruck für die Exponenten dieser Näherungen hergeleitet.
Growth defects in barium‐strontium niobate crystals
Authors: Abramov N. A. , Ivleva L. I. , Kuz'minov Yu. S. , Myzina V. A. , Polozkov N. M.
Published: July 2007

The paper is concerned with the results of investigation of barium‐strontium niobate chemical composition change, of the lattice parameter, microhardness of the crystal region. Analysis reveals the increase of the barium content up to 4% and the change of the crystal lattice parameter by 10−3 Å, leading to considerable tensions and crystal cracking. The etching of the slides perpendicular to the growth axis has been realized as well as the decoration of the fresh cleavages by anthraquinone vapours which indicate the electric inhomogenity in the crystal volume.
The simultaneous crystallization of ZnSnP2/ZnSiP2 — a heterocombination
Authors: Pietsch C. , Buhrig E. , Boudriot H. , Deus K. , Siegel W.
Published: July 2007

In the solution growth of ternary semiconductors tin can be used as solvent. In this case the phase purity resp. the generation of a solid solution of the reaction products obtained is of interest. This problem was investigated using the growth of ZnSiP2 from tin solutions. For characterizing the phases obtained by the growth X‐ray diffraction. Mössbauer spectroscopy, electronoprobe analysis, luminescence spectroscopy, DTA‐measurements and electrical measurements were used. The results of these measurements allow the following statements within the limits of measuring.

The growth of the pure ZnSiP2 from tin melts is possible.

The phases ZnSnP2 and ZnSiP2 are generated side by side by a nonstoichiometric amount weighed of silicon.

The solubility of ZnSnP2 in ZnSiP2 or reverse could not be pointed out.

The precipitation of ZnSnP2 on ZnSiP2 takes place epitaxially.
On the Dissolution of Grown Synthetic Quartz Inside the Autoclaves
Authors: Kotru P. N.
Published: July 2007

Some results of microtopographical investigations on various habit faces of hydrothermally grown cultured quartz crystals are reported. Circular hillocks with a background of minor rhombohedral surface as dull as the surface surrounding the hillocks are illustrated. The dullness of the surfaces is attributed to microetching of bulk quartz crystals. Unusual etch patterns on major rhombohedral faces are illustrated. Oriented raised humps on rhombohedral faces are explained to be as a result of interaction of etch fronts from different etch nuclei surrounding the humps. Rare observations of oriented depressions on trigonal trapezohedron and prism faces are reported. Possibilities that may lead to etching of bulk quartz crystals both inside as well as outside the growing chambers are discussed. From the considerations of various facets of the processes involved, it emerges that the etch patterns are indicative of quartz crystals getting etched in the growing chambers itself when the supply quartz is exhausted and where the growing chambers is the hottest.
Zusammenhang zwischen Gitterdeformation und Verfärbungserscheinungen in synthetischen Quarzeinkristallen
Authors: Härtwig J. , Dietrich B. , Böttger R. , Lübke G.
Published: July 2007

Bei synthetischen Quarzeinkristallen mit Rauchverfärbungsstreifen senkrecht zur Wachstumsrichtung besteht ein Zusammenhang zwischen der Absorption im optischen Bereich und der Gitterkonstantenänderung der verschieden stark verfärbten Gebieten der Art, daß beide einander proportional sind.
Beitrag zur Verteilung der Hauptkomponenten bei der Darstellung von AIIBIVC2V‐verbindungen mittels Gasphasentransports, dargestellt am Beispiel von ZnSiP2
Authors: Winkler K. , Schulz U. , Hein K.
Published: July 2007

Bisher vorliegende Untersuchungsergebnisse bei der Darstellung von ZnSiP2 mittels Gasphasentransportes wiesen auf die Existenz von Konzentrationsprofilen der Hauptkomponenten im Kristallisationsraum hin. Unter Einsatz von Zn‐65 wurde das Kristallisat einer radiometrischen und metallographischen Analyse unterzogen. Dabei wurden Konzentrationsunterschiede zwischen den Kristallen in Abhängigkeit vom Ort der Kristallisation ermittelt und der Zinkgehalt im Kristallinneren gemessen. Ein Anstieg der Zinkkonzentration zum Ampullenende hin und zum Kristallinneren ist typisch. Binäre Phasen wurden nachgewiesen. Zum Konzentrationsausgleich wurden die thermische Nachbehandlung und der Mehrfachtransport mit unterschiedlichem Ergebnis erprobt.
Einkristalline Abscheidung von SiC auf arteigener Unterlage
Authors: Leonhardt A. , Selbmann D. , Wolf E. , Schönherr M. , Herrmann C.
Published: July 2007

Durch thermische Zersetzung von SiCl4 und CCl4 werden im Wasserstoffstrom einkristalline Schichten von n‐leitendem 3C–SiC auf kommerziellen p‐leitendem 6H–SiC bei 1750°C abgeschieden. Die Morphologie der Schichten werden in Abhängigkeit von der Wachstumsrate beschrieben. Die EPD‐Werte liegen zwischen 6,3 × 102 und 3,4 × 103 cm−2. Stapelfehler und Mikrozwillinge nach (111) werden nachgewiesen.
Zum Verhalten der röntgenografischen Verzerrungsverteilung von Versetzungen bei niedrigen Fourierordnungen
Authors: Röll H.
Published: July 2007

Für zylindrische Kristallite mit einer Schrauben‐ bzw. Stufenversetzung auf der Zylinderachse werden für niedrige Fourierordnungen die Momente der röntgenografischen Verzerrung berechnet und daraus qualitative Eigenschaften der Verzerrungsverteilung hergeleitet. Diese Verzerrungsverteilungen zeigen für große Verzerrungen einen Abfall umgekehrt proportional der dritten Potenz der Verzerrung und einen von der Fourierordnung abhängigen Abschneideradius bei großen Verzerrungen. Eine analytisch angegebene Verzerrungsverteilung mit den genannten Eigenschaften ist dem Warren‐Averbach‐Verfahren mit einer Gaußverteilung und auch einer von Wilson angegebenen Verzerrungsverteilung ohne Abschneideradius überlegen.
Magnetic susceptibility calculation of semiconductor compounds AIIIBV in the MOLCAO approximation
Authors: Sirota N. N. , Vitkina Ts. Z.
Published: July 2007

A semiempirical model for calculating magnetic susceptibility, which allows to substantiate the magnetic susceptibility dependence on the crystal symmetry and the nature of interatomic interaction in it, has been proposed. Diamagnetic term of magnetic susceptibility in one electron approximation together with radius mean square of atoms in the AIIIBV compound is shown to be determined by the distance, position of gravity center of charge cloud, the degree of covalency of the compound and the overlapping integrals. Paramagnetic term of magnetic susceptibility in the approximation of the first coordination sphere is determined by the averaged transition energy between the excited and unexcited p‐levels of the system, the bond nature in a semiconductor and the overlapping integrals. Numerical results satisfactorily agree with the experimental data.
Precipitation and dissolution of KCaCl3 impurity in NaCl crystals
Authors: Andreev G. A. , Buritskova L. G. , Hartmanová M.
Published: July 2007

Impurity precipitation in NaCl crystals containing CaCl2 and KCl in various proportions is studied by means of flotation density measurements. The paper is concerned with the determination and dissolution, the kinetics and activation energy, and the mechanism of nucleation. Two temperature regions for solid solution decomposition were revealed. The characteristic stages in density variation upon isochronal annealing are shown to be correlated with radical changes in the X‐ray diffraction patterns. Evidence is given that the nucleation is heterogeneous for the stable phase and homogeneous for the metastable one. – The activation energy in the low‐temperature region has been found to be 0.8 ± 0.1 eV, which suggests precipitation to be diffusion‐limited. From the kinetics studies it follows that the composition of the metastable phase corresponds to KCaCl3 and the rate‐controlling stage in stoichiometric crystals is a K+ diffusion.
Der Einfluß der Stapelfehlerenergie und der Atomgröße‐Schubmodul‐Differenzen auf Versetzungsstruktur und ZSD ermüdeter kfz‐Metallegierungen
Authors: Blochwitz C. , Mecke K. , Stephan R.
Published: July 2007

Die zyklische Spannungs‐Dehnungs‐Kurve von NiFe‐ und NiCo‐Legierungen hängt von der zyklischen Verformungsvorgeschichte ab. Unterschiedliche Versetzungsgrobkonfigurationen (einphasen‐ oder zweiphasenähnliche Struktur) sind die Hauptursache dieses Verhaltens. Geringe Stapelfehlerenergie (NiCo) und große Atomgröße‐Schubmodul‐Wechselwirkung (NiFe) beeinflussen die Versetzungsstruktur in der gleichen Weise.
Die Temperaturabhängigkeit des Dotanteneinbaus bei der Abscheidung von Siliziumepitaxieschichten aus der Gasphase (I) Der Phosphoreinbau und die Natur des Segregationskoeffizienten
Authors: Kühne H.
Published: July 2007

Ausgehend von der Anwendung des Henry‐Gesetzes N = (P)1/i · 1/Hi auf die Partialdrucke der einzelnen, im Dampfgleichgewicht des elementaren Phosphors vorhandenen Molekülarten wird der Segregationskoeffizient von Phosphor zwischen Gasphase und wachsender Siliziumepitaxieschicht (kSegr.; P) mit der reziproken effektiven Henry‐Konstante (1/Hi*) identifiziert. Damit wird der Einbau von ionisierten Phosphoratomen in die Silziumschicht als elementarer Prozeß angesehen. Der Segregationskoeffizient ist nicht nur von der Temperatur, sondern auch von der Phosphordampfzusammensetzung und damit von der Dotanteneinbaukonzentration abhängig.
Chemistry of organic eutectics (III). α‐Naphthol‐naphthalene system
Authors: Singh N. B. , Rastogi P. , Singh Narsingh Bahadur
Published: July 2007

Relative supercooling, linear velocity of crystallization and microstructure for the α‐naphthol‐naphthalene eutectic system have been investigated in order to understand the mechanism of eutectic solidification. Heat of fusion measurements indicate the possibility of molecular association in the liquid melt. The effective distribution coefficient, direction of solute transference, and separation efficiency have also been determined using zone melting technique.
Beitrag zur Kenntnis der Beziehungen zwischen Aktivierungsmechanismus und Strukturänderungen in Festkörpern Untersuchungen zur Verteilung amorpher Bereiche auf schwinggemahlenen Quarzoberflächen
Authors: Steinike U. , Ebert I. , Jedamzik J. , Kretzschmar U. , Hennig H.‐P.
Published: July 2007

Es wurden die Dicken röntgenamorpher Schichten nach verschiedenen Methoden abgeschätzt und mit Literaturwerten verglichen. Die mittlere Schichtdicke liegt zwischen 10 bis 30 nm und ist weitgehend unabhängig von der erreichten Amorphisierung und der spezifischen Oberfläche. Ein Modell der Verteilung der röntgenamorphen Bereiche um das Quarzkorn wird vorgestellt.
Die Züchtung von Pb1−xSnxTe‐Einkristallen mit vorgegebenem Zusammensetzungsgradienten mit Hilfe einer wandernden Lösungsmittelzone
Authors: Link R. , Nötzel N. , Ermisch W.
Published: July 2007

Durch entsprechende Wahl der Zusammensetzung der Lösungsmittelzone, des Quellkristalls und des Substratkristalls lassen sich mit Hilfe einer im Temperaturgradienten wandernden Lösungsmittelzone (Travelling Solvent Method, TSM) etwa 0,5 mm dicke Pb1−xSnxTe‐Einkristallscheiben mit variierendem x herstellen. Die aus Untersuchungen an einer Elektronenstrahl‐Mikrosonde ermittelte Zusammensetzung der Kristalle wird mit Hilfe einer elementaren Theorie beschrieben. Es werden Angaben über die Zinnsegregation bei der Züchtungstemperatur 585 °C gemacht.
Etching behaviour to MgO crystals in relation to chemical reactions
Authors: Sangwal K. , Patel T. C.
Published: July 2007

Experimental results of an investigation of the etching behaviour of {100} faces of MgO crystals under different etching conditions in acids, alkalies and inorganic salts are presented. It is observed that etching takes place in aqueous solutions of acids and acidic salts and in the melts of NaOH and KOH. On the basis of an analysis of the results it is suggested that the energetics of chemical reactions dictate the choice of etchants for a crystal.
Electron probe microanalysis of CuInSe2 and CuGaSe2 crystals
Authors: Möller W. , Kühn G. , Beier W.
Published: July 2007

A correction procedure for the quantitative electron probe microanalysis of nonstoichiometric crystals in the system CuInSe2–CuGaSe2 is presented and applied to the analysis of the terminal members of the mixtures. In CuInSe2 samples a precipitation of Cu2Se takes place due to an evaporation of volatile compounds with a composition ratio In: Se = 2:3. A similar reaction was observed in the case of CuGaSe2.
XPS‐study of the interaction of air‐oxygen with platinum surfaces
Authors: Wagner N. , Brümmer O.
Published: July 2007

The differences in the XPS spectra of the band regions Pt4f, Ols and VB between cleaned and air exposed polycrystalline platinum samples are discussed. After defined exposure it appears PtOads. and a cation configuration of 5d8 6s1 for platinum. This can be shown by line shapes, especially by the double peak structure of oxygen lines and by the asymmetrical tail on the high binding energy region of Pt4f combined with valence band results.
Crystal and molecular structure of the phenyl‐trimethine‐merocyanine C9ONH9
Authors: Kulpe S. , Schulz B.
Published: July 2007

The phenyl‐trimethin‐merocyanine crystallizes in the space group I 4 with 8 molecules per unit cell. The lattice constants are a = b = 16.121 Å, c = 6.549 Å, α = β = γ = 90°. The intensities were measured with an automatic single crystal diffractometer. The solution of the structure was obtained by applying the convolution molecule method and the R‐value method. The refinement was performed by least‐squares blockdiagonal method to an R‐value of 7.2% for 1067 independent reflexions. The C–C‐bond lengths within the plane of the trimethin chain alternate as in the molecule structure of the morpholylpentamethine‐merocyanine and thus point to a distinct polyenic behaviour. The valence angles within the chain alternate as well. This property indicates a polymethinic behaviour of the molecule. The geometry of the molecule proves the merocyanines to have an intermediate position between the polymethinic and the polyenic state. For a more detailed discussion we refer to the discussion of the morpholyl‐pentamethine‐merocyanine structure.
The investigation of solid state reactions taking place in the AlZn (4.5 at.%)–Mg (2;3 at.%) alloys by interrupted continuous heating
Authors: Sackewitz K.‐H. , Radomsky M. , Löffler H. , Kabisch O. , Ungár T. , Honyek G. , Lendvai J. , Kovács I.
Published: July 2007

The decomposition and dissolution processes taking place in these alloys during continuous heating interrupted at certain temperatures, cooled quickly to RT and heated again are followed by means of TEM, XSAS, resistivity, DTA, and DSC measurements. It could be stated that during these heat treatments the decomposition sequence GP zones η′ happened. The presence of X‐phase could not be pointed out surely.

The GP zones formed at lower temperatures are dissolved partially before the formation and growth of η′‐particles takes place. Indications were found that the presence of η′‐particles in the matrix makes the η′‐precipitates instable in the neighbourhood of the η′‐particles.
Ein Beitrag zur Entstehung von Spannungen und Versetzungen beim Kristallwachstum
Authors: Indenbom V. L.
Published: July 2007

An Hand charakteristischer Beispiele werden halbquantitative und quantitative Methoden zur Abschätzung bzw. Berechnung und Analyse von thermoelastischen Spannungen bei der Kristallzüchtung aus der Schmelze erläutert. Die Spezifik der Bildung thermoplastischer Spannungen in Kristallen mit unterschiedlichen rheologischen Charakteristiken wird betrachtet. Möglichkeiten zur Abschätzung der Versetzungsdichte und ihrer Verteilung im Kristall aus dem axialen Temperaturgradienten, der Größe und Verteilung der thermoelastischen Spannungen und dem Zustand der Spannungsrelaxation werden diskutiert.
Growth kinetics, morphology, and electrical properties of nGaAsnGaN heterojunctions
Authors: Šrobár F. , Procházková O. , Kohout J. , Zelinka J. , Šimeček A.
Published: July 2007

nGaAsnGaN heterojunctions were fabricated by one‐stage conversion of monocrystalline GaAs under varying conditions. Surface and cross section study, performed by means of optical and electron microscopy, indicates that the growth kinetics is essentially controlled by transfer of ammonia molecules across the already grown nitride layer; the diffusion coefficient value at 700°C being 3.1 × 10−10 cm2 sec−1. Current‐voltage behaviour, describable by relations of the type I = I0(T) exp (αV), appears to be dominated by tunneling processes.
Einige Erfahrungen mit dem Wachstum von LiTaO3‐Einkristallen
Authors: Šimáček V. , Tůma P.
Published: July 2007

Einkristalle von LiTaO3 wurden nach der Czochralski‐Methode aus Pt‐Tiegeln gezogen. Sie wurden zur Herstellung von Lichtleitern durch Eindiffundieren von Nb verwendet.
On the coexistence of phases at the α–β transition in quartz
Authors: Semenchenko V. K. , Bodnar I. T. , Fotchenkov A. A.
Published: July 2007

The character of the α–β transition in crystals of natural and synthetic quartz has been studied by measuring the refractive index. The coexistence of two different crystallographic modifications over some temperature range has been established. The α–β phase transition is supposed to be attributed to the near‐critical phase transitions. In synthetic quartz with Al and Fe structural impurity the α–β transition consists of two successive transitions. First the transition from the α‐phase to an intermediate one takes place, then the intermediate phase is transformed into the β‐Phase. Within a certain temperature range there exists only the intermediate phase.
Induction period of the calcium nitrate‐water system
Authors: Pacák P. , Horsák I. , Sláma I.
Published: July 2007

The induction period‐supercooling dependence was measured in calcium nitrate‐water system within the concentration range 1.5–23 mol% of Ca(II). It was found that the behaviour of the system may be described by the equations for transformation kinetics with the use of classical theory of homogeneous nucleation in glasses. From the experimental data values of interfacial tension of the liquid‐solid interface were calculated and correlated qualitatively with the observed stability of the studied system with respect to crystallization.
Change in morphology and dislocation Etch Pits on the (010) Surface of Magnesium Orthosilicate Crystals
Authors: Desai C. C. , John V.
Published: July 2007

Investigations made on the etching behaviour of magnesium orthosilicate crystals in hydrochloric acid and melts of potassium and sodium hydroxides are described. It is shown that the morphology and orientation of the etch pits depend upon the concentration, composition and temperature of the etchant used. At low concentrations of HCl acid solution, the boat shaped pits produced are oriented along [100] direction while in concentrated acid, the hexagonal pits produced are oriented along [001] direction. At intermediate concentrations of about 5 N HCl acid the pits are square. KOH melt at 400 °C is found to produce rectangular pits with their longer sides parallel to [100] direction. The effect of a mixture of KOH and NaOH in different proportions in the melt is investigated. It is observed that square pits are obtained in melt of the mixture of KOH and NaOH in the proportion of 6:4 respectively. The mechanism responsible for the change in orientation of etch pits have been explained. The implications are discussed.
Influence of Chromium and Titanium Oxide Dopants on the Real Structure and the Mechanical Properties of Corundum Single Crystals
Authors: Gościńska T. , Auleytner J.
Published: July 2007

The real structure and the mechanical properties of pure and doped corundum single crystals have been investigated. The single crystals were obtained by the Verneuil‐method. The results allow to propose two different models concerning the influence of the chromium and titanium oxide on the properties of corundum single crystals.

Optimum concentration of the chromium oxide impurities was approximately determined, from which corundum single crystals with higher hardness can be obtained. It was stated that titanium oxide impurities with some concentrations made the crystals more fragile without plastically changes in the region of the individual mosaic blocks.
Estimation of Core Energy of Dislocations from Etching Data
Authors: Sangwal K.
Published: July 2007

From data on the activation energy of dissolution at a surface and at a dislocation for the {100} planes of MgO crystals the dislocation core energy is estimated employing Schaarwächter's theory of etch pit formation.
Zur Bestimmung des Zerstäubungskoeffizienten bei der Ionenätzung
Authors: Mamaev G. I. , Seidowski E. , Ledovskoj V. P.
Published: July 2007

Die Berechnung des Wechselwirkungsquerschnitts bei der Ionenzerstäubung unter Anwendung einer allgemeinen Formel für die Streuung geladener Teilchen, die für beliebige Winkel gilt, erlaubt in Verbindung mit der Nikulin'schen Abschirmfunktion eine genauere Bestimmung des Zerstäubungskoeffizienten nach dem Kaskadenmodell. Die erhaltenen Werte befinden sich in guter Übereinstimmung mit dem Experiment.
The Molecular and Crystal Structure of p‐methyl‐phenyl‐glyoxyacid‐p‐chloranilide
Authors: Höhne E. , Seidel I.
Published: July 2007

Using X‐ray crystal structure analysis of the title compound the positions of all the atoms (including all H atoms) in the monoclinic unit cell with the parameters a = 13.900 Å, b = 5.138 Å, c = 17.956 Å and β = 91.05° and the space group P 21/n were localized. The existence of an intramolecular N—H(N)…︁ O(1)‐bridge was inferred, whose H‐bridge acceptor predominantly is the π‐electron density of the carbonyl group. At the same time the H(N) atom participates in the intermolecular bridge NH(N)…︁ O′(1) to the symmetry‐equivalent neighbouring molecule. H‐bridge‐like interactions of the two phenyl hydrogen atoms H(6) and H(15) to the carbonyl oxygen O(2) have also been inferred from the torsion angles.
Structural Properties of S‐alkylated Dithiolene Chelates (I). Crystal and Molecular Structures of Bis(S‐ethyl‐ethene‐1,2‐ dithiolato)palladium (II) and Bis(S‐ethyl‐ethene‐1,2‐dithiolato) platinum (II)
Authors: Sieler J. , Richter R. , Kaiser J. , Kolbe R.
Published: July 2007

Bis(S‐ethyl‐ethene‐1,2‐dithiolato)palladium(II), Pd(S2C4H7)2, is monoclinic, P 21/n, with a = 7.598(1) Å, b = 10.445(2) Å, c = 8.031(1) Å, β = 95.3(1)° and Z = 2. The structure was determined by 893 independent reflections and refined by the block‐diagonal leastsquares method to R = 0.12. The chelate molecule is nearly planar and the palladiumsulfur distances are 2.278(6) Å and 2.403(6) Å.

Bis(S‐ethyl‐ethene‐1,2‐dithiolato)platinum(II), Pt(S2C4H7)2, is monoclinic, P 21/a, with a 13.114(2) Å, b = 12.873(2) Å, c = 7.446(2) Å, β = 96.1(1)° and Z = 4. The structure was solved from 2040 independent reflections. The compound is not isomorphic with the isomeric palladium complex. In the unit cell there exist two symmetry independent molecules. The platinum‐sulfur distance is 2.280 (6) Å.
Dynamic Aspects of Dislocation Behaviour Near Low‐Angle Boundary in Molybdenum Single Crystals
Authors: Novikov I. I. , Kantor M. M. , Yermishkin V. A. , Plastini V. M. , Timofeev V. N.
Published: July 2007

The dislocation behaviour was inventigated in specimens of monocrystals of molybdenium during in — situ stretching in the direction [001] near low — angle twist boundary which was close to be parallel to the direction of the external force. Low‐angle boundary is easily penetrable for the fast moving nonscrew dislocations and acts as an effective stopper for screw dislocations which are quite parallel to the forming boundary dislocations. The mixed tipe dislocations emission by the low‐angle boundary was noticed. On the stage when plastic deformation is performed mainly by the motion of screw dislocations the “relay‐race”‐like transmission of the dislocations motion through the boundary was observed.
Plastic Deformation of BCC Metals — Open Problems
Authors: Šesták B.
Published: July 2007

For a deeper understanding of the plastic behaviour of bcc metals a detailed knowledge of the mobility of screw dislocations, which is intimately connected with their core structure, is necessary. A critical review of our present knowledge indicates an almost absolute lack of quantitative information on screw dislocation mobility at finite temperatures. Therefore, a detailed experimental and theoretical study of these processes is an open problem of great importance. Such a study would be of great value for the entire field of plastic deformation of bcc metals.
HVEM In‐situ Deformation Investigations on Cyclically Deformed Nickel Single Crystal
Authors: Mecke K. , Messerschmidt U.
Published: July 2007

In‐situ deformation investigations were carried out on thin foils of a nickel single crystal which was cyclically pre‐deformed. The motion of dislocations does not start in the whole specimen simultaneously but begins at localized places in the dislocation‐poor regions. The plastic deformation may be characterized by a collective movement of dislocations. Measurements of the effective stress show its characteristic dependence on the position in the direction of the Burgers vector. There are clear indications of structural changes in the dense regions of dislocations at strains exceeding the cyclic total strain amplitude.
Method of Evaluating Geometrical‐Statistical Parameters of the Interaction between Dislocations and Point Obstacles from Electron Micrographs
Authors: Messerschmidt U. , Appel F.
Published: July 2007

Electron micrographs of MgO crystals deformed in the HVEM show screw dislocations of curly shape. The dislocations are pinned at localized obstacles and bow out between them. The paper describes a measuring procedure for the geometrical interaction parameters between the dislocations and the obstacles. Such are the effective stress, the obstacle distance and the force acting on the obstacles. The procedure consists in a graphical fit of loops calculated by the DE WITT‐KOEHLER line tension model to the observed dislocation segments.
Crystal and Molekular Structure of Piperidinium‐acet‐p‐Cl‐anilide‐chloride
Authors: Reck G. , Bannier Gloria
Published: July 2007

Piperidinium‐acet‐p‐Cl‐anilide‐chloride crystallizes in the triclinic space group P 1 with 2 formula units C13H18ON2Cl2 in the unit cell. The lattice constants are a = 10.471 Å, b = 12.545 Å, c = 6.149 Å, α = 72.14°, β = 105.70° and γ = 105.21°. Bond lengths, bond angles and the conformational flexibility were determined by X‐ray structure analysis. The crystal structure contains dimeres consisting of drug molecules connected by hydrogen bonds.
The Crystal Structure of 3‐Methoxy‐estra‐1,3,5(10)triene‐16αBr,17αOH
Authors: Szulzewsky K.
Published: July 2007

The steroid 3‐Methoxy‐estra‐1,3,5(10)triene‐16αBr,17αOH crystallizes in the orthorhombic space group P 212121 with lattice constants a = 30.653(5) Å, b = 9.039(2) Å, c = 6.098(1) Å. The single molecule has an intramolecular OH…︁ Br interaction. Intermolecular interactions are only of van der Waals type. Ring A is nearly planar, ring B has a nearly half chair conformation, ring C has a chair conformation and ring D an envelope conformation.
The Diffusion Influence in Melt on the Solid Solution Formation for a System of Eutectic Type
Authors: Cherepanova T. A. , Didrihsons G. T.
Published: July 2007

On the example of a model eutectic system an investigation was carried out on the crystallization regularities taking into account diffusion mass transfer to the interface under diffusion and kinetic growth regimes. The authors bring forward a possible mechanism of formation of continuous series of supersaturated solid solutions under speedy hardening from a liquid phase. The shape of kinetic phase diagrams was found.
α‐substituted phosphoryl compounds (III). The crystal and molecular structure of diphenyl[1,3‐benzodithiolyl‐(2)]‐phosphinoxide, C19H15OPS2
Authors: Kulpe S. , Seidel I.
Published: July 2007

Diphenyl[1,3‐benzodithiolyl‐(2)]‐phosphinoxide crystallizes in the monoclinic space group P 21/c with four molecules per unit cell. The lattice parameters are a = 9.600 Å, b = 11.270 Å, c = 16.484 Å; β = 99.72°. With X‐ray diffraction data collected at an automatic four circle diffractometer, the crystal structure has been solved by direct methods and refined to an R‐value of 0.08 for 2690 measured and symmetrically independent reflections. The substance is a derivative of acetales of formyl diphenyl phosphine oxides. Correlations between the geometry of the structure and NMR‐data are of interest.
On the reproducibility of the orientation distribution function of texture samples from pole figures (I). Relationship between the odf and pole figures
Authors: Matthies S.
Published: July 2007

The explicit relationship between the orientation distribution function and the pole figures measured by means of diffraction experiments is derived and discussed. It is shown that these pole figures have a higher symmetry than the ODF, i.e. that it is impossible to reproduce unambiguously the ODF from pole figure datas only. From this circumstance follows that the ODF reproduced by help of usual methods are falsified and contain ghost phenomenas.
Strength investigations of subsurface regions stressed by tribomechanical loading
Authors: Kampf S. , Schilling A. , Solondz D. , Wuttke W.
Published: July 2007

Polycrystalline copper and monocrystalline iron were tribomechanically loaded in a defined way. By fundamentals of a continuum mechanical analysis of the stress field and a transmission electron microscopical investigation of the dislocation arrangement conclusions were made regarding the crack nucleation, the crack propagation and the wear resistance. The proved development of a dislocation cell structure is an adaptation of the material to the friction loading to tolerate a high number of loading cycles without wear.
Electric conductivity and lattice disorder of PbMoO4 crystals
Authors: Bollmann W.
Published: July 2007

From differential thermal analysis (DTA), thermal etching, perfectly reversable redox treatments and electric conductivity it is concluded that the Pb/Mo ratio of the PbMoO4 crystals is always 1 and that phase transitions do not occur. Pb3+ ions detectable by an absorption band at 435 nm cause a p‐conductivity due to the reaction Pb3+ ⇌ Pb++ + e+. At elevated temperatures the p‐conductivity increases with increasing oxygen partial pressure of the surrounding atmosphere. The influence of foreign ions on the concentration of ionic and electronic defects in PbMoO4, CaMoO4, PbO, and PbTiO3 can be explained by an anti‐Frenkel disorder of the oxygen ion sublattice. For PbMoO4 crystals the mobility O− ion vacancies and the free formation enthalpy of anti‐Frenkel defects are found to be vv = \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop - \limits_T^{9160} $\end{document} exp (−1.15 eV/kT) cm2 K/Vs and gAF = 3.6kT −2.2 eV, respectively.
Precipitation process in a cast alloy Al‐3.5 wt.pct Zn‐4 wt.pct Mg
Authors: Dzuong Lecong
Published: July 2007

The structural changes during ageing of an alloy containing 3.5 wt.pct Zn and 4 wt.pct Mg were studied by means of transmission electron microscopy. It was shown that the precipitation process in this alloy differs from that in the alloys having high Zn/Mg ratios. The following phases were observed: hexagonal transition T′ phase, cubic stable T phase, hexagonal transition β′ phase, cubic stable β phase and hexagonal transition β′ phase. The precipitation process proposed the formation of two kinds of clusters in the beginning, i.e. Zn‐rich and Mg‐rich clusters. The former gradually transforms into GP zones and then into the T′ and T phases. The latter transforms into the β′ and β phases. The existence of the β′ phase seems to be a result of the segregation of the solute elements in the cast alloy.
Real structure investigations of LiNbO3 single crystals grown by the flux method
Authors: Hemmerling J. , Hergt R.
Published: July 2007

The real structure of flux grown LiNbO3 crystals is investigated by etching technique, X‐ray topography, and optical polariscopic method. The main defects are microdomains, dislocations and minor impurities of V3+−ions. The crystals do not contain growth striations. The mean dislocation density is in the order of 103 cm−2. The main origin of the defects seems to be post‐growth mechanical stress. The results are discussed in comparison to the real structure typically found in the case of Czochralski crystals.
Experimental proof on an anisotropic anharmonic DEBYE‐WALLER factor for silver
Authors: Vega H. , Försterling G. , Kleinstück K.
Published: July 2007

On silver were done high‐precise measurements of the thermal dependence of integrated intensities of coherently scattered X‐ray radiation. The experimental results attained at the low temperature range (80–286) K agree with calculations according to the model of the lattice vibrations suggested by WILLIS (1969) which bases on anharmonicity and anisotropy of the lokal potential. An anisotropic anharmonic DEBYE‐WALLER factor of silver was detected on this basis. The measurements at the temperature range close to and above room temperature to 1150 K didn't yield any significant confirmation of the model.
Perspective fields of application of texture topography and further development of its apparatus
Authors: Born E. , Schwarzbauer H.
Published: July 2007

The applications of a new X‐ray topography method designed for investigations of polycrystalline samples are closely related to reasons of different X‐ray reflectivity from point to point in the surface of the specimen. The discussion of these relationships is followed by suggestions for an apparatus. The most simple one is based on the principle of the “camera obscura” locating the diaphragm of the camera at the place where a diffracted beam is focussed either according to the focussing principle of Guinier or according to Bragg‐Brentano, respectively.
Modifications test of vacuum deposition Ni/Cr films with Mn and Si for thin film resistors
Authors: Schippel E.
Published: July 2007

For producing Ni/Cr thin film resistors an Si addition would be especially suitable to reduce the TCR, as Si forms several phases with Ni and Cr. By evaporating powder mixtures deposition thin films were produced with constant Cr portions of 20 at.%, 30 at.% and 40 at.% and from 5 to 50 at.% Si or Mn, rest Ni. Whereas the layers containing Mn have an exclusively positive TCR, there is a shift to negative TCR in the layers containing much Si.
Topographic studies of an X‐ray interferometer of czochralski‐silicon
Authors: Dietrich B. , Kittner R. , Zaumseil P. , Grosswig S.
Published: July 2007

Contrary values of lattice deformation result from X‐ray Moiré pattern and from reflection topographs in a double crystal diffractometer. An explanation is presented on the base of lattice deformations which vary only in the direction of growth of the crystal.
Growth of bulk zinc chalcogenide single crystals from the vapour phase and their use for laser screens of projection colour television
Authors: Bulakh B. M. , Kozlovsky V. I. , Moiseeva N. K. , Nasibov A. S. , Pekar G. S. , Reznikov P. V.
Published: July 2007

Results on ZnSe, ZnSexS1−x and ZnS crystal growing from the vapour phase up to 7.5 cm3 in volume are described. Crystals were grown on sapphire, ZnS, ZnSexS1−x and quartz glass substrates without a contact of the growing crystal with a growth ampoule and using the molten tin as a heating medium. Large high‐purity crystals with a density of etch pits of 103 cm−2 were obtained They exhibited an effective exciton luminescence and rather high radiation efficiency (30 ± 10% for ZnSe at T = 77 K). This made it possible to use these crystals for fabricating laser screens for a cathode ray tube. The main laser parameters obtained on a ZnSe screen at T = 80 and 300 K using a 75 keV electron beam excitation are presented. The light power output reached 0.8 W at T = 80 K; this allowed to obtain a 10 cd · m−2 TV image of 1.5 × 2 m2 in area.
The comparison of the properties of hydrogen forms of zeolite T obtained by the treatment with hydrochloric acid af 100 °C or through the ammonium form and its decompostion
Authors: Cichocki A.
Published: July 2007

The modification of zeolite T through the ammonium form and its decomposition is in comparison with the treatment with hydrochloric acid, more effective and more selective for the obtainment of hydrogen forms with high decationization degree at low dealumination. The calcination at 500 °C introduced between the treatments of zeolite with acid allows for the stabilization of the structure and enlargement of the H+/K+ exchange.
Growth kinetics, habit modifications and surface designs of lead iodide grown by the new gel technique
Authors: Abdulkhadar M. , Ittyachan M. A.
Published: July 2007

Lead iodide crystals have been grown in silica gel by the new gel technique by the inter action between colloidal lead tartrate and KI solution. The crystals are found to exhibit interesting surface designs. Growth kinetics and habit modifications of the crystal have been investigated. Two dimensional surface nucleation and screw dislocation are found to partake in the growth process of the crystals.
Photo‐EPR of deformation‐produced defects in GaAs
Authors: Wosiński T.
Published: July 2007

Deformation‐produced paramagnetic centres have been studied in GaAs crystals uniaxially compressed at 400° using EPR technique (X band). The effect of light with photon energies from 0.4 to 1.5 eV on the populations of the centres has been investigated. On the basis of the experimental results a model is proposed which locates the energy levels of two of the centres at Ec − 1.05 eV and Ev + 0.75 eV.
A contribution on the self‐stress fields of fully coherent precipitates
Authors: Bönning H. , Löffler H.
Published: July 2007

The self‐stress fields caused by fully coherent precipitates inclusive the local densities of the elastic energy were calculated by means of the linear isotropic theory of elasticity for few coerses of the concentration of alloyed elements in the surrounding matrix.
Distribution coefficient of foreign ions in ionic crystals‐A function of the ionic radius
Authors: Bollmann W.
Published: July 2007

The distribution coefficient k of foreign ions in melt‐grown crystals is found to be proportional to R−B and R+B in the case of large and small ionic radii R, respectively. As to alkali halides and alkaline‐earth fluorides the exponent B corresponds to the number of nearest neighboured or charge‐compensator ion sites in the case of homovalent and heterovalent foreign ions, respectively.