bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal behaviour of beta‐uranophane
Authors: De Camargo W. G. R. , Souza I. M.
Published: July 2007

Beta‐uranophane from Perus, SP, Brazil‐ has been heated progressively up to 1.350°C, and its thermal behaviour has been investigated thoroughly by several methods: thermogravimetry, differential thermal analysis, optical measurements (variation of refraction indices), infra‐red spectroscopy, and X‐ray diffraction (powder photographs at room temperature of previously heated material, and powder photographs at high temperatures in special cameras). – The mineral seems to be stable up to a temperature of 200°C, confirmed by the several experimental procedures. The differential thermal analysis gives a sharper point of transformation at 165°C, which should be ascribed to water evaporation (zeolitic water). At this temperature the beta‐uranophane should change to another isostructural compound, containing a small amount of crystallization water. Alternatively, crystal structure of the mineral could be transformed into a random layer structure, due probably to loss of the structural water. This kind of crystal disorder induces, as a rule, in the X‐ray powder diagrams, absences of the hkl reflections, leaving merely the prismatic (hk0 and 0kl) and the pinacoidal reflections (h00, 0k0, 00l, and h0l). This could explain the small number of observed lines in the powder photographs of the material heated above 200°C.

A new phase transformation is reported in the temperature interval of 700 to 800°C. This transformation should be related to the beta‐uranophane chemical breakdown into two or more new crystalline phases. The chemical composition of such products is discussed in the paper. As the temperature rises to a higher level, a phase transformation takes place between 1000 and 1200°C and yet another one in the range of 1200 to 1350°C. The latter transition has been detected with the high temperature camera, and could be ascribed to the formation of an alloy between the platinum holder and the breakdown products of beta‐uranophane.

Infra‐red espectroscopy has been proved inadequate for the study of the phase transformations of beta‐uranophane. However, some conclusions could be reached in connection with the water content at several temperature levels.
Application of the method CORDAL based on the combination of the convolution molecule method and the residual analysis to the structure determination of 3‐dehydro gibberellin A3
Authors: Kutschabsky L. , Reck G. , Kulpe S. , Höhne E.
Published: July 2007

In connection with studies of the solid state photolysis the crystal and molecular structure of 3‐dehydro gibberellin A3 was determined by X‐ray analysis. The final discrepancy factor R was 0.078. The packing of the molecules in the crystal explains the preference of intramolecular photoaromatization in contrast to the topophotodimerisation of the corresponding methylester upon UV‐irradiation. In this structure determination the method CORDAL, based on the combination of the convolution molecule method by Hoppe and Paulus and the residual analysis, was applied successfully.
Anwendung der „Optimalfilter‐Methode”︁ bei der röntgendiffraktometrischen Bestimmung von Differenz‐Elektronendichten
Authors: Försterling G. , Blau W. , Stephan D. , Sonntag J.
Published: July 2007

Die Methode der Fouriersynthese mit Differenzen zwischen den gemessenen und theoretischen Strukturamplituden zum Nachweis Bindungsbrücken in Metallen und Metall‐Legierungen wird dargestellt. Die Meßstrategie und die Auswertemethodik werden nach der „Optimal‐Filter”︁‐Methode für diesen Anwendungsfall entwickelt und am Beispiel kubisch‐raumzentrierter Legierungen erprobt.
A steady‐state procedure of liquid phase epitaxy
Authors: Kühn G. , Neels H. , Höbler H.‐J. , Sutter D.
Published: July 2007

A turning‐shifting technique is reported permitting the deposition of epitaxial layers at constant temperatures and with small melting volumes. Basic parameters of GaAs are studied and the development of crystal growth is followed up in dependence on temperature.
Untersuchung der lokalisierten magnetischen Momente und der Nahordnung in Fe‐Cr‐Al‐ und Fe‐Mn‐Al‐Legierungen mittels Neutronenstreuung
Authors: Wieser E.
Published: July 2007

An zwei ferromagnetischen Legierungssystemen mit hohem elektrischen Widerstand (Fe–Cr–Al, Fe–Mn–Al) wurden Nahordnungseffekte und die lokalisierten magnetischen Momente von Fe, Cr und Mn mittels magnetisch diffuser Neutronenstreuung untersucht. Für Fe–Cr–Al wurden die Nahordnungsparameter der ersten drei Nachbarschaftssphären bestimmt. Für Fe–Mn–Al werden die Al‐ und die Mn‐Verteilung qualitativ diskutiert. Der Wirkungsquerschnitt für die magnetisch diffuse Neutronenstreuung an Systemen mit Nahordnung wurde von binären auf ternäre Legierungen verallgemeinert.
A new experimental method for recrystallization studies
Authors: Žáček S. , Vacek V. , Skřivánek J. , Karel M.
Published: July 2007

A new experimental apparatus for and a method of studying the recrystallization process in the system KAl(SO4)2 · 12 H2O – water are presented. The mean particle size growth and the expansion of the distribution curve depending on particle size are shown for selected time periods, and the effect of the initial concentration of the particles in suspension on the recrystallization rate is described.
Das Kristallwachstum von BaAl2Si2O8
Authors: Oehlschlegel G. , Abraham K. , Flörke O. W.
Published: July 2007

Im System BaO‐Al2O3‐SiO2 wurden neben einem metastabilen Mischkristall Ba1−0,5xAl2−xSi2+xO8 zwei stabile und eine metastabile Modifikation der Zusammensetzung BaAl2Si2O8 untersucht. Die deutlichen Unterschiede der Keimbildung sowie der Geschwindigkeit und Anisotropie des Kristallwachstums dieser kristallinen Phasen führen zur bevorzugten Bildung von Gliedern der Mischkristallreihe. Für die Temperaturwechselbeständigkeit von keramischen und glaskeramischen Produkten ist das gezielte Erzeugen der metastabilen Mischkristalle oder der nadelig gewachsenen Kristalle der Tieftemperaturmodifikation von Bedeutung.
Determination of linear growth rates of crystals (I). Calculation of linear growth rates of individual crystal faces from overall rates
Authors: Matuchová Marie , Nýavlt J.
Published: July 2007

The presented paper (Part I and II) is devoted to the fundamental principles of the kinetics of crystal growth. The number of studies in this field has been increasing and some authors have introduced different terms and definitions. To avoid possible mistakes and confusions, the individual definitions of the rate of crystal growth are specified and their interrelations are discussed in detail.

Basic methods for measuring the kinetics of crystal growth are described. The rate of growth of individual crystal faces or the average rate of crystal growth can be determined using the selected experimental method. The presented study demonstrates that the results obtained by either of the two measuring methods (linear rate of growth of crystal faces and average rate of crystal growth) can be interrelated.

The established method of calculating linear growth rates of individual crystal faces is based on an analysis of the time dependence of the volume of a growing crystal. The relationship between the linear growth rates of individual crystal faces and the over‐all crystal growth rate is presented and a method for assessing the linear growth rates of individual crystal faces from over‐all growth rate data, which can be measured readily, is suggested.
Verfahren und Vorrichtung zur Bestimmung von Krümmungen einkristalliner, scheibenförmiger Körper
Authors: Sommerfeldt H. , Mohr U. , Jegerlehner K.
Published: July 2007

Bei der Herstellung von Halbleiterbauelementen tritt das Problem der Verkrümmung einkristalliner Scheiben auf, ein Ausdruck der im technologischen Prozeß mit jedem Bearbeitungsschritt zunehmenden Zerstörung der Kristallperfektion. Die Bestimmung der Verkrümmung kann folglich Aufschluß über den Einfluß eines jeden Bearbeitungsschrittes auf die inneren Spannungen des Kristallkörpers geben. In dem Beitrag wird ein solches Verfahren beschrieben, das auf der Ausnutzung der Braggschen Reflexion eines Röntgenstrahles an den Netzebenen des Kristallkörpers zur Bestimmung der Netzebenenneigung beruht. Es wird eine auf diesem Verfahren beruhende Vorrichtung vorgeschlagen, die einen hohen Automatisierungsgrad zuläßt.
Die Struktur der Oberfläche fester Körper
Authors: Hieke M.
Published: July 2007

Am Beispiel einer von n = – ∞ bis n = 0 erstreckten linearen Kette von Massenteilchen, auf der alle Teilchen n = 1, 2, 3, …︁ fehlen, werden die Beträge sowie die Verteilung der Angriffspunkte des Kräftesystems diskutiert, die am Ende der Kette angebracht die periodische Struktur aufrecht erhalten. Das am Ende der Kette anzubringende Kräftesystem soll die Kräfte gleichwertig ersetzen, die sonst von den fehlenden Teilchen herrühren. Verschieden vorgenommenen Verteilungen der Angriffspunkte der Einzelkräfte entsprechen unterschiedliche Störungen, die entweder auf die nahe dem Ende gelegenen Teilchen beschränkt sind oder das gesamte Gitter erfassen können. Das eindimensionale Beispiel entspricht dem Problem der Oberflächenstruktur und Oberflächenspannung fester Körper. Die Störung innerhalb der Oberflächenschicht ergibt eine Resultante der Kräfte, die als Oberflächenspannung bezeichnet wird.
Etch pits on Te basal planes
Authors: Kalinski Zb. , Lehmann G.
Published: July 2007

Prism face dislocation densities of Czochralski‐grown Te single crystals were determined and a new etchant for the basal planes tested, these being prepared by spark‐erosive cutting.
Critical behaviour and internal bias of TGS and isomorphous crystals depending on growth conditions
Authors: Tsedrik M. S. , Zaborovski G. A.
Published: July 2007

The critical behaviour of TGS and isomorphous DTGS, TGSe and DTGSe single crystals grown at various conditions was investigated. The growth dependences for ΔT in heating and cooling regimes and shift ΔT of the temperature of maximal permittivity were found. These dependencies were explained in terms of existence of internal biasing fields these being measured vs temperature.
Über das Wachstum und den Abbau von Gallium‐ und CBr4‐Einkristallen aus eigener Schmelze
Authors: Gutzow I. , Pancheva E.
Published: July 2007

Es wird eingehend die Morphologie und der Temperaturverlauf von Kristallwachstum und Kristallabbau zweier Modellsubstanzen — Gallium und Tetrabromkohlenstoff — in der Kapillare untersucht. Diese beiden Substanzen sind durch eine verhältnismäßig niedrige Schmelzentropie ΔSm ausgezeichnet, wobei im Falle von CBr4 der ΔSm‐Wert niedriger ist als jener kritische Wert von ΔSm (4 cal/grad. Mol), unter welchem nach manchen theoretischen Folgerungen die Bildung atomar diffuser Kristallfronten zu erwarten sind. Besonders eingehend wird der Temperaturverlauf der Abbaugeschwindigkeit beider Modelle untersucht. — Die erhaltenen Resultate zeigen, daß sich Gallium, dessen schmelzentropie hart über dem kritischen ΔSm‐Wert liegt, wie alle anderen, hohe Schmelzentropien aufweisende Substanzen verhält. Die Morphologie und das Kristallisations verhalten von CBr4 hingegen können gut durch die Annahme einer diffusen Kristallfront erklärt werden.
Stacking faults in deformed zinc and magnesium single crystals
Authors: Lavrentev F. F. , Pokhil Yu. A.
Published: July 2007

Using the transmission electron microscopy dissociated dislocations containing stacking faults were observed in Mg single crystals, deformed in (0001) <1120> slip system, and in Zn single crystals deformed in {1122} <1123> slip system.

The overlapping flat stacking faults lying in {1102} planes and dissociated triple nodes in (0001) planes are observed in Mg. In Zn flat stacking faults are found in {1122} planes. The value of stacking fault energy γ has been determined in Mg crystals (γ ⋍ 10 erg/cm2). Such a low value of γ is attributed to the segregation of impurities on dislocations.
Versetzungsätzungen und Mikrohärtemessungen an druckverformten Reinsteiseneinkristallen
Authors: Schott G. , Graetz M.
Published: July 2007

Die bei einmaliger und wiederholter Belastung in Metallen auftretende Verfestigung erklärt man vorrangig durch das Versetzungsgeschehen. Die vorliegenden Untersuchungsergebnisse stellen eine Beitrag zum Nachweis des Zusammenhanges zwischen Versetzungsdichte und Verfestigung dar.
Über die Versetzungsverteilung bei der Züchtung von Siliziumeinkristallen
Authors: Geil W. , Schmugge K.
Published: July 2007

Ausgehend von dem aus der Literatur bekannten Vorstellungen wird eine Beziehung zwischen Temperaturfeld, Spannungen im Kristall und Versetzungsdichte hergeleitet. Bei diesen Überlegungen ist der von ALEXANDER und HAASEN beschriebene Mechanismus, nach dem die effektive Schubspannung πeff = π — A √N für die Versetzungsbildung entscheidend ist, vorausgesetzt. Am Beispiel eines zylindrischen Siliziumeinkristalls, der einem parabolischen Temperaturfeld ausgesetzt war, wurde der theoretische Befund mit experimentellen Ergebnissen verglichen. Durch die Kenntnis der Beziehung zwischen Spannungsfeld und Temperaturfeld ist auch die Beziehung zwischen Versetzungsverteilung und Temperaturfeld gegeben.
Growth of large oriented metal single crystal plates
Authors: Modrzejewski A , Paszkowicz W. , Warchoł S.
Published: July 2007

A method of growing large oriented metal single crystal plates is presented. Crystal plates without any mechanical treatment are suitable for neutron diffraction work. The mosaic spread of these crystals is smaller than that of cylindrical single crystals.
Bildung von α‐Martensit im Schnittbereich von ϵ‐Martensitplatten
Authors: Schumann H.
Published: July 2007

In Stählen wird die Keimbildung von α‐Martensitkristallen aus dem Austenit erleichtert, wenn ϵ‐Martensit vorhanden ist. Besonders in den Schnittbereichen von ϵ‐Martensitplatten, die eine 〈110〉γ‐Richtung haben, entsteht bevorzugt α‐Martensit, wie bei geeignet zusammengesetzten und vorbehandelten Legierungen metallographisch gezeigt werden konnte. Auch in den Schnittbereichen anderer Scherprodukte, wie Stapelfehler und Zwillinge, liegen günstige Atomanordnungen für α‐Martensitkeime vor. Mit Hilfe von Schermatrizen wurden die Verzerrungen in den Schnittbereichen von 2 ϵ‐Martensitplatten, von 1ϵ‐Martensitplatte und 1 Zwilling sowie von 2 Zwillingen berechnet und mit der Verzerrung bei der martensitischen γ → α‐Umwandlung verglichen.
Röntgenografische Untersuchungen an hochgeschwindigkeitsverformten Kupfer und Stahl
Authors: Schierhorn Eike , Strassburger G.
Published: July 2007

Das Materialverhalten krz‐ und kfz‐Metalle hängt von der Verformungsgeschwindigkeit ab. Streckgrenzen und Verformungsmechanismen unterscheiden sich bei Hochgeschwindigkeitsverformung von denen bei quasistatischer Verformung. Röntgenografische Untersuchungen und Mikrohärtemessungen an Kupfer und einigen Stählen (Mk3Al, 16MnCr5, X8CrNiMoTi1811) zeigen die Abhängigkeit von Teilchengrößen, inhomogenen Gitterverzerrungen, Stapelfehlerdichte, Mikrohärte und Tiefe von Verformungsschichten von der Verformungsgeschwindigkeit bzw. dem Verformungsgrad.
The application of scanning microscopy in the study of brittleness in copper and its alloys
Authors: Joszt Kazimierz , Ciura Ludwik
Published: July 2007

Among others the following results were attained: the transcrystalline ductile fracture of copper and some of its alloys resulting from a considerable plastic deformation, with numerous dimples, in the middle of which there usually appear second phase inclusions. — Intercrystalline fracture due to cracks along the grain boundaries may be different, sometimes scarecely to be disguished from the transcrystalline cleavable fracture. It should rank among brittle fracture as its appearance is always characterized by considerable brittleness of the material. Brittleness of copper and its alloys result from precipitations of these phases on the grain boundaries.
Zur Kristallisation von Melilith aus der Glasphase
Authors: Schreiter P. , Werner M.
Published: July 2007

Kristallisationsversuche von Melilithglas werden quantitativ ausgewertet und Beziehungen zwischen Kristallisationstemperatur und Habitus hergestellt. Eine temperaturabhängige nichtstationäre Induktionsperiode wird festgestellt und auf der Grundlage der Glasstrukturtheorie nach ROY gedeutet. Die Abhängigkeit der linearen Wachstumsgeschwindigkeit von der Temperatur wird mitgeteilt. Der sich daraus ergebende Einfluß von Anlagerungsgeschwindigkeit und Diffusion auf den temperaturabhängigen Habitus der Kristalle wird diskutiert.
On the morphology of cadmium sulphide epitaxial layers on germanium, observation of six‐pointed star optic figures and their explanation
Authors: Kamadjiev P. R. , Gospodinov M. M.
Published: July 2007

The morphology was investigated of the cadmium sulphide epitaxial layers, grown on germanium substrate with orientation (111), in a quasi‐closed “sandwich” system in hydrogen atmosphere. Regular hexagonal compound pyramids were observed, tipped and truncated, with a plane slope abruptly changed. With the orientation of the layer (000)CdS ∥ (111)Ge, the orientations of the pyramid planes were determined to be of the type (0113), (0114) and (0115).

Regular six‐pointed optic stars were observed in those pyramids. Explanation of the stars observed is presented. A method is proposed for the determination of the cadmium sulphide layer thickness, using the data from the pyramids and the optic stars. The same stars were obtained with the elaborated models as well.
Messung von Rockingkurven eines polierten CaF2‐Kristalls
Authors: Dietrich B. , Förster E. , Böttger R.
Published: July 2007

Es wird über die Messung von Rockingkurven an einem polierten CaF2‐Kristall nach schrittweiser Abtragung dünner Oberflächenschichten berichtet. Die Auswertung führt zu einer Erweiterung des Raetherschen Modells polierter Oberflächen durch Annahme eines elastisch deformierten Gebietes unterhalb der durch die Politur erzeugten mosaikkristallinen Schicht.
Zu dem Transportsystem VOTeCl und dem Transportverhalten der Vanadinoxide mit TeCl4 (I). Der Transport von Vanadindioxid
Authors: Oppermann H. , Reichelt W. , Krabbes G. , Wolf E.
Published: July 2007

Das thermodynamische Verhalten des Systems VOTeCl wird beschrieben. Von besonderer Bedeutung für das Transportverhalten ist der O2‐Koexistenzgleichgewichtsdruck. Für die Beschreibung des Transportes unterhalb 700 °C ist die Existenz von TeOCl2 in der Gasphase Voraussetzung. Aus dem Zusammenwirken des O2‐Koexistenzgleichgewichtsdruckes mit den diminierenden Gasphasenspezies können die Transportrichtung, die Transportrate und die Sauerstoffan‐ und ‐abreicherung der kristallisierenden Phase berechnet und vorausgesagt werden. VO2‐Einkristalle unterschiedlicher Phasenzusammensetzung werden hergestellt.
Effects of γ‐ray irradiation on the properties of Pb2+ doped potassium chloride crystals
Authors: Damm J. Z. , Kachmiarz M. , Mugeński E. , Opyrchał H. , Poźniak J.
Published: July 2007

Correlations between various properties (e.g. ionic conductivity, dislocation density, colourability, thermoluminescence, thermal recovery) of as‐received and irradiated KCl crystals containing up to about 20 mole · ppm Pb2+ are revealed. On the basis of the above data and the model proposed by MATSUNAMI et al. some speculations regarding the final irradiation product are presented.
The critical flow stress influenced by formation and transformation of precipitations in NaCl:Ca crystals after annealing
Authors: Suszyńska M. , Grau P.
Published: July 2007

The influence of thermal pretreatment of NaCl + 0.7 mole% Ca2+ single crystals on the critical flow stress and its strain rate sensitive part was investigated. On the basis of X‐ray diffraction experiments it could be shown that the characteristic values of mechanical parameters are related to different kinds of precipitates formed at particular annealing temperatures.
Determination of the distribution coefficient of Pb in NaCl crystals by estimation of the lead concentration from the optical absorption in aqueous solutions
Authors: Berg K.‐J. , Fröhlich F.
Published: July 2007

It is shown that the intensity of a UV absorption band of lead ions in aqueous solution of NaCl is linear dependent on the concentration of lead. This can be developed to a simple determination method of lead in NaCl crystals even in the ppm region. Its application on melt grown NaCl:PbCl2 crystals was used for a calculation of the distribution coefficient, for which was found k = 0.24. Furthermore it could be shown that an essential part of lead is evaporated from the melt before the growth process starts so that the real initial concentrations are drastically lower than the nominal concentrations of the melts.
Zur Defokussierungsabhängigkeit der elektronenmikroskopischen Netzebenenabbildung
Authors: Heydenreich J. , Pasemann M. , Werner P.
Published: July 2007

Die Defokussierungsabhängigkeit des Bildkontrastes der elektronenmikroskopischen Netzebenenabbildung wird im Bereiche der Netzebenenabstände von 8 Å bis zu 1,4 Å experimentell untersucht und theoretisch — unter Zuhilfenahme berechneter Phasenkontrast‐Charakteristiken — interpretiert. Während bekannt ist, daß sich im Fall der koaxialen Bestrahlung optimale Bildkontraste bei geeigneter Überfokussierung ergeben, existieren hinsichtlich der schiefen Bestrahlung widersprüchliche Aussagen zum Kontrastgeschehen. In der vorliegenden Arbeit wird gezeigt, daß sich in diesem Fall maximale Bildkontraste bei Überfokussierung erzielen lassen. Eine mögliche Deutung, die den Einfluß der Abweichung von der exakten, symmetrisch‐schrägen Bestrahlung berücksichtigt, wird gegeben.
X‐ray diffraction studies of bismuth tungstate catalysts
Authors: Sinhamahapatra Pratap Kumar , Sinhamahapatra Samarendra , Bhattacharyya Sudhir Kumar
Published: July 2007

Bismuth tungstate catalysts with Bi/W ratios 2/3, 1/1, 2/1, and 6/1 have been investigated after various heat treatments by room temperature X‐ray analysis. The activity and selectivity of Bi2WO6 catalyst are suggested to be connected with the presence of corner sharing W—O octhedra in the bulk of the solid that give rise to tetragonal pyramidal W—O sites at the surface. The very low activity of Bi2(WO4)3 is attributed to edge‐shared octahedral coordination of W while the same of Bi6WO12 is due to tetrahedral coordination of W. The inactivity of Bi2W2O9 may be associated with its typically low oxidation power. The promoting influence of Bi2O3 is to enforce a structural situation on W—O so that W may be present in a tetragonal pyramidal 5‐configuration.
Design of batch agitated crystallizers
Authors: Nývlt J. , Mullin J. W.
Published: July 2007

Basic relationships are derived for batch‐operated crystallizers and simple laboratory procedures are specified for the measurement of design information. Worked examples are given to illustrate the design calculations.
Influence of the surface layer of the solution on the nucleation of fibrillar trimolybdate crystals and their growth on air bubbles
Authors: Hodorowicz S.
Published: July 2007

The effect of the free surface area of solutions on the nucleation of fibrillar trimolydate crystals is described. The nucleation period is inversely proportional to the free surface area of solutions at a fixed volume. The observations of the growth of fibrillar monocrystals on air bubbles are reported.
Etching behaviour of calcium fluoride crystals in hydrochloric acid vapour
Authors: Desai C. C. , Sangwal K. , John V.
Published: July 2007

Etching of octahedral cleavage faces of calcium fluoride crystals in hydrochloric acid vapour has been investigated. It is observed that dislocation etch pits and non‐dislocation elevations are formed. The morphology of etch pits obtained by vapour etching is observed to be different from that obtained by weak acid solutions. The results are discussed in terms of the prevailing etching conditions.
The Kinetics of Dissolution
Authors: Konak A. R.
Published: July 2007

The kinetics of dissolution have been expressed using a generalized dissolution rate equation which combines concentration driving force and area terms and thus enables large amounts of undersaturation to be used in experiments.
Facet Formation in Garnet Crystals
Authors: Petersyan A. G. , Shirinyan G. O. , Ovanesyan K. L. , Avetisyan A. A.
Published: July 2007

Formation of {110} and {211} type facets in rare‐earth aluminium garnet crystals grown along different crystallographic directions is analyzed and it is shown that D/2R parameter (where D is the crystal diameter and R is the curvature radius of spherical growth interface) may be used to characterize the number of originating facets and their configuration in crystals.
Röntgentopographie mit Extremwertnachführung (I) Prinzip der Nachführung und Bildverzeichnung
Authors: Alex V. , Hansch C. , Naumann E.
Published: July 2007

Ein System zur automatischen Nachführung der Reflexionsstellung (ANRES‐System) während des Scanning einer gekrümmten Silizium‐Scheibe wird beschrieben. Es. ist als Zusatz für übliche Lang‐Anordnungen zu verwenden, hat eine automatisch geregelte Eingangsverstärkung, ist relativ unempfindlich gegen stochastische Störungen und gestattet die vollständige Abbildung einer Silizium‐Scheibe. Die Bildverzeichnungen bei der Röntgentopographie mit ANRES einerseits und mit ABAC (automated Bragg angle control) nach van Mellaert, Schwuttke andererseits werden verglichen.
Dielektrische und akustische Eigenschaften von Ag5SbS4
Authors: Brilingas A. , Bucko N. J. , Grigas J. , Samulionis W. , Sheshnitsch J. D.
Published: July 2007

In der vorliegenden Arbeit sind die Ergebnisse der Untersuchung der Mikrowellen dielektrizitätskonstante, der Absorption und der Geschwindigkeit der longitudinalen Ultraschallwellen in Kristallen von Ag5SbS4 dargestellt. Es werden Probleme der Kristallzüchtung und das Wesen des Phasenüberganges in diesen Kristallen diskutiert.
TSM‐gewachsene Halbleiter‐Einkristalle aus (Pb0,8Sn0,2)Te
Authors: Bansaragtschin B. , Link R. , Lehmann G.
Published: July 2007

Unter Anwendung der TSM konnten in einem einfach zu handhabenden Züchtungsverfahren PbSnTe‐Mischkristalle hergestellt werden, die hinsichtlich ihrer Perfektion und Zusammensetzung sowie ihrer elektrischen Eigenschaften untersucht wurden. Die Ergebnisse führen zu dem Schluß, daß bei Vorteil einer kurzen Züchtungsdauer Kristalle in guter Homogenität mit niedrigen LTK und hohen Beweglichkeiten darstellbar sind. Typische erzielte Werte sind p77 ≦ 1017 cm−3, n77 ≦ 1017 cm−3; pμ77 ⋍ 1,6 · 104 cm2/Vs; Abmessungen: 1 × 4 × 4 mm3.
A memory‐effect in KCl crystals
Authors: Turchányi G. , Mátri M. , Tarján I. , Földvári I.
Published: July 2007

It is shown that the photoelectric effect produced by far UV light in KCl crystals of high purity „remembers”︁ the light energy in the F‐band obtained previously by the crystal.
Elektrooptische Hysteresekurven von Strontiumbariumniobat‐ und Bleimagnesiumniobat‐Einkristallen
Authors: Arndt H. , Schmidt G. , Hennig P. , Döhn G. , Zscheyge W.
Published: July 2007

An Strontiumbariumniobat‐ und Bleimagnesiumniobat‐Einkristallen wurde interferometrisch die Änderung des Brechungsindex in Abhängigkeit von der elektrischen Feldstärke gemessen. Die Ergebnisse sind mit den Vorstellungen über die feldinduzierten Phasenumwandlungen in diesen Ferroelektrika mit diffuser Phasenumwandlung vereinbar. Insbesondere weisen die elektrooptischen Schmetterlingskurven darauf hin, daß während der Umorientierung der spontanen Polarisation die unpolare Phase auftritt.
Untersuchungen zur heteroepitaktischen Abscheidung von GaP auf GaAs aus der Sn‐Lösung
Authors: Gottschalch V. , Kramer P. , Butter E.
Published: July 2007

Es werden die verwendeten Züchtungsapparaturen beschrieben und die experimentellen Daten zur Abscheidung von GaP und Ga(AsP) auf GaAs mitgeteilt. Daran schließt sich eine Diskussion des Einflusses der Züchtungsparameter (Temperatur, Abkühlungsgeschwindigkeit, Schmelzenzusammensetzung) auf die Ausbildung des Heteroüberganges und den damit im Zusammenhang stehenden Lösungsmitteleinschlüssen an. Die Auswirkung der Substratfehlorientierung auf die Oberflächenmorphologie wird untersucht.
Halbleiter‐Metall‐Übergang in V3O5
Authors: Brückner W. , Terukov E. I. , Reichelt W. , Moldenhauer W. , Čudnovskij F. A. , Oppermann H.
Published: July 2007

Das V3O5 gehört zu den Magnéli‐Phasen VnO2n−1 und besitzt einen Leitfähigkeitsübergang bei 154 °C. Der Charakter des Überganges, die Änderungen der elektrischen, thermoelektrischen, magnetischen, strukturellen u. a. Eigenschaften und der Einfluß hydrostatischen Druckes und ternärer Komponenten (Dotierungen) auf den Übergang werden beschrieben. Das Verhalten des V3O5 ordnet sich gut in das Eigenschaftsbild der anderen Magnéli‐Phasen ein. Der Übergang ist als Ladungsordnungs‐Ladungsunordnungs‐Übergang zu charakterisieren bei wesentlicher Wirkung der Elektronenkorrelation.
The influence of the mode of hardness increase on the dislocation mobility of the crystal with NaCl lattice
Authors: Boyarskaya Yu. S. , Grabko D. Z. , Pishkova D. S. , Shutova S. S.
Published: July 2007

The influence of the three types of hardening (1 – radiation hardening; 2 – the hardening in lowering of temperature; 3 – the hardening in the series of KCl‐NaCl‐NaF‐LiF‐MgO crystals) on the length of dislocation rosettes arms is investigated. This length characterizes the dislocation ensemble mobility in the nonuniform stress field. It is shown that the change of microhardness and that of mobility of dislocations correlate well while introducing the radiation damage. In contrast to it the microhardness rise does not cause marked decrease of the length of rosettes arms in the other two cases. The conclusion is made that the length of rosettes arms depends not only upon the value of crystal hardness but also upon the mode of origin of this value. On the (001) plane of the crystals under investigation it is found that the length of dislocation rosettes arms depends on the indentor orientation. A possible explanation of this phenomenon is proposed.
On the chemical transport of some niobium oxides with TeCl4 (I). Calculation of the system Nb/O/Te/Cl and the transport of NbO2/NbO2.417
Authors: Ritschel M. , Oppermann H.
Published: July 2007

This series of two papers deals with the chemical transport of niobium oxides with TeCl4. – With chemical transport of NbO2, using TeCl4 as transport agent, NbO2.417 is deposited at first followed by NbO2. The peculiarities of this transport are attributed to the oxidizing action of the transport agent and to considerable reaction inhibitions in the starting solid. Monocrystals of NbO2 and NbO2.417 are obtained without deposition of any other phases. The morphology of the crystals is described. The transport behaviour in the system Nb/O/Te/Ci is calculated. The calculated and experimental results agree well.
Process control in the multisection continuous crystallizer
Authors: Malczewski J.
Published: July 2007

The equation of steady linear growth rate of crystals is presented. It can be used by a design of the multisection continuous crystallizer.
Microhardness of single crystals of the calomel family
Authors: Barta Č. , Barta Č. , Brožek V. , Hájek B.
Published: July 2007

Microhardness of Hg2Cl2, Hg2Br2 and Hg2I2 single crystals has been measured on (001) and (110) faces using the indenter after Vickers. It has been found that the microhardness of the first two homologues differs only slightly whereas the iodide is considerably softer: by about 20% on the (001) face and by about 30% on the (110) face. The average microhardness value, calculated from the values obtained on gradually rotating the indenter over 360° on the (001) face, is for Hg2Cl2 and Hg2Br2 practically equal to the microhardness of NaCl (20.3 and 19.4 compared to 19.6 · 107 Pa). The average microhardness of the (110) face is for Hg2Cl2 and Hg2Br2 about 2 × lower and for Hg2I2 about 2.6 × lower than that of the (001) face. In the case of Hg2Cl2 the microhardness of the (001) face has been also calculated from crystallochemical parameters and the results have been found to be in good agreement with the value obtained experimentally for the orientation of the indenter's diagonal parallel to the [100] direction, where the data is the least influenced by the elasticity of the sample (16.6 compared to 18.6 · 107 Pa).
Electron optical identification of precipitations in silicon semiconductor devices
Authors: Pasemann M. , Barna Á. , Werner P. , Hagel H.‐J.
Published: July 2007

In silicon MOS semiconductor devices precipitations were observed by TEM in the boron‐diffused regions. They were identified by using selected area diffraction, high resolution lattice plane imaging, Auger spectroscopy and microanalysis of X‐rays. The results lead to the conclusion that these particles consist of polycrystalline silicon and that oxygen and nitrogen, probably carbon too are concentrated inside the particles. The formation of these precipitations is only due to the technological process of the device manufactoring and does not depend on the silicon starting material.
Wave mechanism of the effect of external fields on crystallization
Authors: Kuznetsov D. A. , Hodorowicz S. , Krymova W. G.
Published: July 2007

Over the region of the electric double layer of the system solution‐crystal, electroacoustic waves are generated by thermal movements of molecules and ions. Electrostatic field of the waves picks out crystal‐forming particles affecting thereby the rate of their deposition. The effect is controlled by the ratio of the frequency of the waves to that of vibrations of molecules in the crystal lattice. When an external variable electric field and a static magnetic field are applied to the system, the latter brings about anisotropy of generation of the electrostatic wave (in the field direction only) and appearance of another wave, transverse to the field, of the frequency higher than that of the longitudinal wave. As a result, asymmetry is produced in the growth rate of orthogonal faces of a crystal.
On the Quantum Theoretical Calculation of Activation Energies for the Self‐Diffusion of Single Atoms and the Diffusion of Adatoms on Metal Surfaces (I)
Authors: Winzer A.
Published: July 2007

By application and modification of the equation given by A. Einstein for calculating the internal oscillation energy of crystals, the activation energies for the self‐diffusion of single atoms on the metal surfaces of Rh, Pt, and for the surfaces diffusion of adatoms on metal surfaces were calculated on the basis of quantum theory from the surface Debye frequency and the bulk Debye frequency, neglecting the frequency distribution.

A comparison of the activation energies calculated by quantum theory with the experimental values of the literature obtained by the field‐ion microscope shows a relatively good agreement for the single crystal surfaces and temperature ranges. The calculation showed a strong increase of the activation energies for the self‐diffusion at higher temperatures and a relatively great dependence on the respective crystal surface of the metal. Analogous results were also obtained for the surface diffusion of adatoms on the metals.
Structural Changes during Post‐Ageing of an Al‐Zn (15 at.%) Alloy between 125 °C and 215 °C
Authors: Löffler H. , Kroggel R. , Kabisch O.
Published: July 2007

The structural changes going on in an AlZn (15 at.%) alloy postaged between 125 °C and 215 °C after pre‐ageing between 20 °C and 90 °C (till start rs = (20…︁ 55) Å are obtained) were followed by means of XSAS‐investigations. The main results are the following:

An increase of rs does not favour the growth of the precipitates during the reversion treatment.

At later reversion times the happening is obviously independent of the pre‐history of the samples.

The integral intensity is decreasing with increase of Trev, but the mean distance (d)‐size (rG) relation between the precipitates is not changed remarkably up to Trev ≈ 200 °C in the early reversion stage.

Conclusions from this behaviour are drawn.
Possibilities for In‐situ Observation of Basic Deformation Processes and of Other Dynamic Processes
Authors: Imura T.
Published: July 2007

The purposes of this paper are to discuss the possibilities of HVEM in‐situ observation for deriving meaningful results on basic deformation processes by illustrating some examples which have been obtained so far and to assess the capabilities of this method to investigate crystal deformation as well as other dynamic processes. First, the experimental procedures developed by our group in Nagoya to study the dynamic behaviour of dislocations are introduced. Research subjects which have been studied effectively by this method so far are illustrated. The lower safety limit of specimen thickness for deriving information typical of bulk materials, the effects of size and free surfaces of a specimen and the effects of electron irradiation etc. are to be discussed to assess the validity of in situ observation of dislocation behaviours. Some prospects on new applications and extensions of in‐situ HVEM for physical and materials research are to be presented, including possibilities for in‐situ observation of other subjects such as diffusion, environmental effects, interface reaction, chemical reaction, defect formation during growing or processing of semi‐conductors, surface treatment and micro fabrication by electron beam etc.
Image Recording by TV Technique
Authors: Herrmann K.‐H. , Krahl D. , Rust H.‐P.
Published: July 2007

Fernseh‐Bildverstärkeranlagen mit Speichergeräten lassen sich für die Auslesung und Verarbeitung von EM‐Bildern in Echtzeit einsetzen. Anhand des Einzelelektronensignals und der Detection Quantum Efficiency (DQE) werden die Dimensionierungsgrundsätze für den Aufbau derartiger Anlagen erläutert und für verschiedene spezielle Systeme geprüft. Während bei hohen Endbildstromdichten ein vom Dynamikumfang der Kameraröhre abhängiger Abfall der DQE in Kauf genommen werden muß, können mit ausreichender optoelektronischer Vorverstärkung bei mittleren Stromdichten Werte von mehr als 0.80 erzielt werden. Der Idealdetektor (DQE = 1) wird bei kleinen Stromdichten mit digitaler Verarbeitung und Speicherung erreicht.
In‐situ HVEM Investigation of Processes Leading to Fracture in Metals
Authors: Wilsdorf H. G. F.
Published: July 2007

The unique features of in‐situ straining to fracture in high voltage electron microscopes have been outlined. Phenomena pertinent to the ductile fracture of metals have been reviewed as they relate to the study of rupture in the microstructural regime. Experimental observations on pure single crystals of silver, α‐iron, and beryllium during fracture have been reported and analyzed. The fracture mechanism can be subdivided into the sequence microvoid initiation, void growth, and void coalescense. It is proposed to distinguish between a primary and a secondary sequence. The latter is applicable to ligament fracture which constitutes the final separation. It was concluded that dislocation cell walls and other boundaries are the initiation sites for microcracks in pure metals and alloys.
Reduction and Oxidation Effects in Metal Oxide Catalysts
Authors: Gai P. L. , Goringe M. J.
Published: July 2007

The behaviour of metal oxide catalysts in a variety of atmospheres is described. In particular the defect structures found in MoO3 under reducing, reoxidising and mixed atmospheres are detailed. Surface relaxation defects (∼ 80 °C), surface domains (120 – 350 °C) and crystallographic shear planes (∼ 380 °C) all occur under reducing atmospheres, being differently resistant to reoxidant to reoxidation. In propylene‐oxygen mixtures the CSPs appear to be unstable.
Submicroscopic Defects in Metals and their Influence on HVEM In‐situ Experiments
Authors: Kiritani M. , Urban K.
Published: July 2007

Recent high‐voltage electron microscopy has provided evidence that substantial submicroscopic changes may occur in specimens examined in the HVEM under conditions where no visible radiation damage occurs. These are the introduction of vacancies by plastic deformation, rapid accumulation of invisible vacancy clusters by electron irradiation, and radiation‐induced contamination and refining of materials. These processes are analysed in terms of defect interactions and the consequences for in‐situ experiments are discussed.
Dielectric reorientation of smectic C, F and I phases
Authors: Pelzl G.
Published: July 2007

As shown for 4 liquid crystalline substances also smectic F and smectic I phases may be reoriented by an electric field similar to a smectic C phase. The threshold voltage of the effect was determined approximately. For one substance the tilt angle of the smectic C and I phase could be measured by means of the dielectric reorientation.
On the chemical transport of molybdenum dioxide with tellurtetrahalogens (I). The Transport System MoO2/TeBr4
Authors: Ritschel M. , Oppermann H.
Published: July 2007

A report is given on the transport behaviour of MoO2 with TeBr4. The fundamentals for the calculation of the gaseous phase composition above a solid phase are explained in the system Mo/O/Te/X. The calculated transport behaviour is compared with the experimental results, and the crystal habit of the obtained MoO2 monocrystals is described.
Generation of dislocations on polished surfaces of dislocation free silicon wafers
Authors: Fischer W. , Heymann G.
Published: July 2007

This paper describes investigations into the influence of wafer defects (surface defects) on the generation of process induced crystal defects in dislocation‐free n‐type silicon material of both Czochralski and zone‐floating techniques. The surface defects are artificial defects, which were produced by scratching with definite forces. The behaviour of scratched silicon surfaces as well as that of scratched and polished silicon surfaces was studied at room temperature and after heat treatment. The experimental results are discussed.
Stability of dislocations in MgO single crystals at high temperatures
Authors: Moriyoshi Y. , Ikegami T. , Matsuda Sh. , Sekikawa Y. , Shirasaki Sh.
Published: July 2007

The dislocation structures of MgO single crystals annealed at 1900 °C for 3 hrs and at 2000°C for 1 hr were observed electron microscopically, and it was found that the following reactions took place at high temperatures: a/2 〈110〉 + a/2 [110], = a [100], a/2 [110] + a/2 〈1101〉 = a/2 [011]. The resultant dislocations were sessile. Their interaction with impurities would make the subgrain boundaries stable.
The reproduction of the orientation distribution function (ODF) of a polycrystalline material from pole figures
Authors: Pospiech J.
Published: July 2007

A detailed analysis of the relation between the orientation distribution function (ODF) and the pole figure is made.
Structure and morphology of oxide deposition on SiO2 (I) correlations between parameters of layer formation and structure
Authors: Bräuer K. , Meyer K. , Müller B. , Müller E.
Published: July 2007

The oxides of Ge, Sn and Ti were produced by reaction of the adequate metal tetrachlorides in dependence on reaction parameters (pressure, temperature, time) on crystalline and non‐crystalline SiO2 substrates. Structure and morphology of the formed oxides were investigated by electron diffraction and electron microscopy. In dependence on the reaction conditions results on the degree of crystallisation and on the particle size distribution could be received. On the basis of the obtained results of investigations conceptions for the mechanism of layer formation were derived.
Investigation of dislocation kinetics in α‐Fe monocrystals with the help of etching technique
Authors: Reinhold Ch. , Wuttke W.
Published: July 2007

Results of the etching technique concerning dislocation arrangements in regions near the surface are introduced after tribomechanical loading on (001) surfaces of α‐Fe‐monocrystals. Moreover, the load stress field related to the critical shear stress is calculated and discussed. For the etching of grown in and newly developed dislocations a solution of 2% nital was used.
Kinetics of FCC and diamond type binary crystal growth (I) lattice model and kinetic equations
Authors: Cherepanova T. A.
Published: July 2007

The lattice model is presented for describing the growth kinetics of binary crystals with various symmetry of crystallographic lattices (for example, ‐fcc, ‐bcc, simple cubic, diamond type). The system of kinetic equations of growth of binary crystal faces for different crystallographic face orientations is obtained. The discussion is given concerning applicability of the interphase model “with overhangs” and “without overhangs”.
The detection of impurities on metallic surfaces by means of the electron energy loss spectroscopy
Authors: Heyroth W.
Published: July 2007

The energy analysis of backscattered low‐energy monochromatic electrons is used to investigate the appearances on crystal surfaces in the vacuum during thermal treatment. Up to 500 K hydrocarbons can be detected by electronic excitation. In the interval from 600 K to 1100 K the presence of a carbon‐contamination layer follows from the excitations of plasmons. The thickness of the layer influences the ratio of the elastically and inelastically backscattered electrons. The material analysis of the clean surfaces due to temperatures above 1200 K is performed by the excitations of the upper inner atomic shells.
Study of the Raman Polarization Spectra of the Single Crystal Phillipsite
Authors: Pechar František
Published: July 2007

The Raman polarization spectra of a single crystal of natural phillipsite in the wave number region 50–4000 cm−1 were measured at laboratory temperature. The vibrations observed in analysis of the measured polarization spectra can basically be divided into 4 groups: a) H2O‐vibrations, b) Internal vibrations of bonds within the (Al, Si)O4 tetrahedra, c) External vibrations between tetrahedra, d) Optical translational modes of the crystal lattice.
Growth of gallium antimonide epitaxial layers on indium arsenide substrates
Authors: Pramatarova L. D. , Tretjakov D. N.
Published: July 2007

In the present work the possibility is demonstrated of growing gallium antimonide epitaxial layers on indium arsenide substrates using the liquid phase epitaxial (LPE) method.

The influence is nivestigated of the growth conditions on the morphology of the surface and interface of the epitaxial structures InAsGaSb. The optimum technological regimes for growth of heterostructures in the system InAsGaSb are found.
Evaluation of the predictive performance of biased regression estimators
Authors: Friedman David J. , Montgomery Douglas C.
Published: July 2007

Regression models are widely used in forecasting, either directly as prediction equations, or indirectly as the basis of other procedures. The predictive performance of a regression model can be adversely affected by both multicollinearity and high‐leverage data points. Although biased estimation procedures have been proposed as an alternative to least squares, there has been little analysis of the predictive performance of the resulting equations. This paper discusses the predictive performance of various biased estimators, emphasizing the concept that the predictive region, as well as the strength of the multicollinearity, dictates the choice of appropriate coefficient estimators.
Linear constraints and the efficiency of combined forecasts
Authors: Clemen Robert T.
Published: July 2007

Studies of combined forecasts have typically constrained the combining weights to sum to one and have not included a constant term in the combination. In a recent paper, Granger and Ramanathan (1984) have argued in favour of an unrestricted linear combination, including a constant term. This paper shows that for the purpose of prediction it may make sense to impose restrictions on the combining model because of potential increases in forecasting efficiency. Empirical results show that small gains in forecasting efficiency can be obtained by restricting the linear combination of GNP forecasts from four econometric models.