bluuebunny/crossref_metadata_2025 huggingface dataset:
A new method of studying anisotropy of crystals
Authors: Nikolova Elka G.
Published: July 2007

A new method is proposed of studying the anisotropy in crystal wafers cut out in respective orientations. For this purpose the TWYMAN effect, discovered in 1905 in the processing of optical glass, is used. It is shown that this effect, the physical nature of which is described in detail in another work of ours, is in force also with crystal wafers which bend to a strictly spherical surface in an isotropic state and to a characteristic ellipsoid surface in an anisotropic state. In the latter state a definite ratio exists of the large to the small axis of the ellipsoid, characterising the anisotropy of a given orientation.
Zur quantentheoretischen Berechnung von Aktivierungsenergien für den Stoffübergang an Phasengrenzflächen von Ionenkristallen bei Kristallisationsprozessen (I). Zur Bestimmung von Aktivierungsenergien für den Stoffübergang an Phasengrenzflächen leichtlöslicher Salze mittels radioaktiver Nuklide
Authors: Winzer A.
Published: July 2007

Es wird über die Bestimmung von Aktivierungsenergien für die Stoffübergangsprozesse an Phasengrenzflächen von Ionenkristallen mittels der Methode der markierten Atome berichtet. Um aus der Temperaturabhängigkeit der Stoffübergangszahlen reproduzierbare Aktivierungsenergien zu erhalten, müssen die Einflußfaktoren Rührgeschwindigkeit, Übersättigung, Vorbehandlung und Oberflächenbeschaffenheit der Kristalle, Korngrößenverteilung und Suspensionsdichte konstant gehalten werden. Es wurden für verschiedene Temperaturbereiche unterschiedliche Aktivierungsenergien erhalten, die mit der Desolvatation der Ionen sowie dem Einbau der Ionen in das Kristallgitter erklärt werden.
Zur Rolle der Gefügegrenzen beim Sintern von Einstoffsystemen
Authors: Schatt W.
Published: July 2007

Es wird ein Abriß des Sintergeschehens im Sinterzwischen‐ und ‐spätstadium unter besonderer Berücksichtigung des Einflusses der Grenzen der Gefügeelemente und der dazu von Ja. E. Geguzin entwickelten Modellvorstellungen gegeben. Auf die Möglichkeiten einer Versetzungsneubildung während des Sinterns („Selbstaktivierung”︁) sowie den Einfluß einer erhöhten Geschwindigkeit des Aufheizens auf isotherme Sintertemperatur wird hingewiesen.
Zur quantentheoretischen Berechnung von Aktivierungsenergien für den Stoffübergang an Phasengrenzflächen von Ionenkristallen bei Kristallisationsprozessen (II). Zur Berechnung von Aktivierungsenergien auf quantentheoretischer Grundlage
Authors: Winzer A.
Published: July 2007

Es wird gezeigt, daß zwischen der Aktivierungsenergie für den Stoffübergang an Phasengrenzflächen von Ionenkristallen bei Kristallisationsprozessen und der Frequenz der longitudinal‐optischen Phononen eine quantenmechanische Beziehung besteht. Dies ist dann der Fall, wenn der Einbau der Ionen in das Kristallgitter der geschwindigkeitsbestimmende Schritt des Stoffübergangs ist, was bei hohen Rührgeschwindigkeiten, niedrigen Übersättigungen und Temperaturen > 25°C annähernd realisiert ist.
Zur Heteroepitaxie von AIBIIIC2VI‐Verbindungen – Interpretation von RHEED‐Diagrammen
Authors: Tempel A. , Schumann B.
Published: July 2007

Bei der epitaktischen Abscheidung von Halbleitern des Typs AIBIIIC2VI auf einkristallinen Unterlagen mit einer dreizähligen Flächensymmetrie wächst der in der Chalkopyritstruktur kristallisierende Deposit mit der {112}‐Fläche auf dem Substrat auf. Es wird gezeigt, daß eine eindeutige Unterscheidung über die vorliegende Art der epitaktischen Verwachsung mittels RHEED‐Untersuchungen stets möglich ist, wenn die atomaren Streufaktoren der I‐ und III‐Atome hinreichend unterschiedlich sind und/oder das Achsen‐verhältnis c/a wesentlich vom Wert 2 abweicht. – CuInSe2/GaAs und CuGaSe2/GaAs weisen eindimensionale Epitaxie auf.
On the volume transformation kinetics of cellular precipitation in f.c.c. nickel‐indium alloys
Authors: Budurov S. , Bojinov V. , Russew Kr.
Published: July 2007

The volume transformation kinetics of cellular precipitation in f.c.c Ni‐In alloys is studied. Precipitation occurs by instantaneous nucleation of two phase pearlite type cells on the grain boundaries. The experimental data was treated on the base of modified by Cahn Kolmogorov‐Avrami rate law for the case of grain boundary nucleation with site saturation in the earliest reaction stage. – The precipitation of the dissolved in the supersaturated matrix indium is governed by cell boundary diffusion; the activation energy was found to be about 65000 cal/mole.
Brittle fracture of single crystals and active structure of cleavage surfaces
Authors: Distler G. I.
Published: July 2007

By the method of vacuum decoration at an electronmicroscopic scale with the use of lowangle electron diffraction the dependence of brittle fracture of alkali halide crystals and of the active structure of cleavage surfaces on the character of ordered distribution of point defects in crystals has been studied. The occurrence of cleavage steps reflects the presence in crystal volume, where brittle fracture took place, of a high degree of periodicity of point defects mainly in one crystallographic direction. The smooth areas of the cleavage surface reflect the existence in these places of a periodic distribution of point defects in two mutually perpendicular crystallographic directions. Coincidence of periods between the cleavage steps with the periods in the arrangement of point defects on smooth areas of the cleavage surface allows the steps to be regarded not only as elements of the geometric microrelief but primarily as electrically active linear elements of the crystal surface, reflecting the linear arrangement of point defects. Together with cleavage steps exhibiting a stable in time activity there arise cleavage steps with an extremely high, but rather shortlived activity being the consequence of the brittle fracture process proper. The electrically active linear elements of the point defect lattice – linear elements of the potential relief of the surface – play a most important role in heterogeneous processes, in particular crystallization processes.
A study of the influence of short‐range order, clustering and crystal lattice defects on positron annihilation in α and α + β brass
Authors: Dlubek G. , Brümmer O.
Published: July 2007

A theoretical model is proposed allowing the consideration of the influence of local neighbourhood of an atom on the positron density enhancement at one or another type of atom in a binary alloy. With the help of this model the direction of the change of angular correlation peak height caused by appearance of short range order or clustering can be predicted. Cu–Zn‐alloys containing 5.4, 15, and 37 weight % Zn are investigated. The peak height of samples quenched from 300°C. show a weak minimum at 90°C. This seems not to be caused by the increase of short‐range order but rather by a process of clustering. probably by segregation of Zn atoms at stacking faults and dislocations. The observed recovery of plastically deformed brass can be well explained by annealing out of vacancies and following recrystallization, where the α + β brass shows characteristic deformation induced properties. Peak height measurements of recovery of crystal lattice defects in binary alloys seems to be only weakly influenced by effects such as short‐range order or tendency of clustering. The formation energy of monovacancies in Cu‐37 wt% Zn is determined to be (0.81 ± 0.02) eV.
Die Züchtung homogener Mischkristalle mit großer Segregationsneigung nach dem Bridgman‐Verfahren am Beispiel des pseudobinären Systems CdxHg1–xTe
Authors: Dittmar G.
Published: July 2007

Bei der Erstarrung von CdxHg1–xTe im Bridgman‐Ofen mit geringer Ziehgeschwindigkeit wachsen wegen der erheblichen Unterschiede zwischen Liquidus‐ und Solidustemperaturen Kristalle mit sehr unterschiedlicher molarer Konzentration x. Bei höheren Ziehgeschwindigkeiten kristallisieren die Barren mit gleichmäßigerer molarer Konzentration x. Die Ursache der verbesserten Qualität der Barren und die Ergebnisse der praktischen Untersuchungen werden beschrieben und diskutiert.
Beitrag zur Züchtung von ZnSiP2 unter nichtstöchiometrischen Bedingungen aus der Gasphase in Auswertung mikroanalytischer Untersuchungen
Authors: Baum H. , Winkler K.
Published: July 2007

Das aus der Gasphase abgeschiedene röntgenographisch einphasige und stöchiometrisch zusammengesetzte ZnSiP2 besitzt einen spezifischen Widerstand > 103 Ωcm und örtlich begrenzte Lumineszenzspektren. Die Existenz von Fremdphasen, vorhandene Inhomogenitäten sowie Stöchiometrieabweichungen im ZnSiP2 waren mögliche Ursachen für diese physikalischen Eigenschaften. Es wurde versucht, fremdphasenhaltiges ZnSiP2 aus der Gasphase abzuscheiden. Die ZnSiP2‐Synthese und ‐Kristallisation erfolgte deshalb mit nichtstöchiometrischen Siliziumeinwaagen. Der Phasenaufbau der Kristalle wurde lichtmikroskopisch und mit Hilfe der Elektronenstrahlmikroanalyse untersucht. Bei unterstöchiometrischer Siliziumeinwaage (– 50 mol% Si) enthält die ZnSiP2‐Matrix die binären Phasen ZnP2 und Zn3P2. Unter überstöchiometrischen Bedingungen (> 100 mol% Si) scheiden sich ZnSi13P2‐Schichten auf dem ZnSiP2 ab. Eindeutige Unterschiede in den physikalischen Eigenschaften konnten zwischen stöchiometrischem einphasigem und fremdphasenhaltigem ZnSiP2 nicht nachgewiesen werden.
Dielectric, piezoelectric, elastic properties and internal friction of TGSe crystals with large unipolarity
Authors: Varikash V. M. , Tarasevich E. V. , Pupkevich P. A.
Published: July 2007

In this work we have studied influence of temperature and external electric field on dielectric, elastic, piezoelectric properties and internal friction of D, L‐α‐alanine doped triglycine selenate crystals. Experimental result analysis allows to conclude that ferroelectric materials with stable physical properties may be created on doping crystals foundation.
Powder feeder for crystals of large diameter grown by the verneuil technique
Authors: Falckenberg R.
Published: July 2007

To grow crystals of large diameter ( ≈ 50 mm) by the flame fusion process it is necessary to feed powder with a flow rate of ≈ 2 g/min into the gas stream, the grain size being as small as possible. The properties of vertically and horizontally excitated sieves are compared. A sieve arrangement with horizontal and vertical vibration is described, which at a mesh width of 90 μm has a powder flow of up to 5 g/min. The long range constancy was within ± 8%. Sieves with a mesh width < 90 μm can be used if an ultrasonic disintegrator is mounted above the feeder sieve. Sapphire and Mg–Al spinel crystals up to 65 mm in diameter could be grown.
Growth and characterization of mixed Sr: Ca tartrates
Authors: Patel A. R. , Arora S. K.
Published: July 2007

Single crystals of Sr1−xCaxC4H4O6 · 4 H2O of different compositions and forms were grown by controlled diffusion of ions through suitable silica gels and characterized. Pycnometer density, lattice parameter, dislocation density, dissolution, cleavage, etc. are some of the interesting features which distinguish mixed crystals from the pure ones.
Investigations of the energy flow of X‐ray wavefields in crystals
Authors: Gerward L.
Published: July 2007

The energy flow of the X‐ray wavefields in the Laue case of diffraction and its importance for X‐ray topography and interferometry are discussed.
Zum Problem der Zweikristall‐Topographie von kleinen Defekten mit Bragg‐Bragg‐Reflexion
Authors: Kies J. , Köhler R. , Möhling W.
Published: July 2007

Das Kontrastverhalten kleiner Defekte, wie sie bei Oxidation an Silizium‐Oberflächen entstehen, wurde mittels Zweikristalltopographie in Rückstrahlanordnung untersucht.

Offensichtlich durch Oberflächenrelaxation des Spannungsfeldes bedingt, ändert sich der Kontrast wesentlich stärker mit der Eindringtiefe als mit der Orientierung der reflektierenden Netzebenen zu möglichen Burgersvektoren. Da die Eindringtiefe für unterschiedliche Reflexe stark variiert, scheint ohne Computer‐Simulation keine überzeugende Ermittlung der Natur der Defekte möglich zu sein.
Surface tension of soluble inorganic salts, from crystallization measurements
Authors: Söhnel O.
Published: July 2007

A method is suggested for the determination of crystal‐solution interfacial tension σ on the basis of data obtained when studying the mechanism of a layer‐wise growth of the soluble‐salts crystals. The essential data for calculating the values of σ by this method are the height and distance of the individual steps on the surface of a growing crystal. The values of σ were evaluated for NH4H2PO4, KH2PO4, CdI2 and Pb(NO3)2.
Advances in energy dispersive X‐ray microanalysis
Authors: Wendt M.
Published: July 2007

Some of the recent advances in energy dispersive X‐ray microanalysis of bulk specimens are reviewed with special emphasis on the developments having led to more accurate results. Following a brief description of instrumental developments the sources of background counts and the background correction are discussed. The final chapter deals with some useful applications of the background. In conclusion, one can state that in many cases the energy dispersive spectrometer yields results the accuracy of which is comparable to that of crystal spectrometers. In special cases the reproducibility achievable with the EDS can even be better.
Micromorphology and defects of non‐doped gallium arsenide layers
Authors: Astakhov V. M. , Toropov A. I. , Stenin S. I. , Zaletin V. M. , Korzhov V. I.
Published: July 2007

Electron microscopy was used to study non‐doped GaAs layers obtained in a chloride system Ga‐AsCl3‐H2. Electron concentrations is 1013–1015 cm−3, mobility at liquid nitrogen temprature reaches 200000 cm2/v. sec. It is shown that a fraction of the growth surface taken with (110) faces is less for films with less electron concentration. The main type of defects in pure GaAs layers is precipitates at pinning centres of growth steps. Estimations based on microdiffraction patterns and irradiation effects show that the impurity concentration in them is 1016–1019 cm−3. The impurity in precipitates is assumed to be electrically non‐active, mainly, in interstitial positions.
Impurity diffusion of 114In in Cu
Authors: Krautheim G. , Neidhardt A. , Reinhold U.
Published: July 2007

Using the tracer‐standard sectioning technique the impurity diffusion of indium in copper has been investigated in the temperature range from 798.1 to 1081.0°C. For the frequency factor and the activation energy, respectively, the following values were determined: D02 = 1.87 cm2 · s−1; Q2 = 2.034 eV. The results are compared with predictions of theoretical models of the impurity diffusion in metals.
Kinetics of precipitation of nickel ammonium sulphate hexahydrate from aqueous solutions
Authors: Söhnel O. , Mullin J. W.
Published: July 2007

The precipitation of nickel ammonium sulphate [Ni(NH4)2(SO4)2·6H2O] prepared by mixing of equimolar aqueous solutions of (NH4)2SO4 and NiSO4 has been studied at 25 °C. Precipitation induction periods and the number of crystals formed per unit volume have been determined experimentally as functions of supersaturation for values of Sa, H < 2.6. The mechanisms of nucleation and crystal growth are assessed by comparing the experimental results with theoretical predictions. In this system, heterogeneous nucleation and crystal growth are assessed by comparing the experimental results with theoretical predictions. In this system, heterogeneous nucleation appears to operate at Sa, H < 1.3, whereas at Sa, H > 1.6 crystals are generated predominantly by homogeneous nucleation and grow by a polynuclear mechanism. The interfacial tension of nickel ammonium sulphate crystals in contact with their supersaturated solution is estimated to be about 20 mJ/ m2.
Gyrotropic properties and birefringence of Smx Tb1−xFeO3 in spin reorientation range
Authors: Sirota N. N. , Lomako I. D.
Published: July 2007

The polar diagrams of the SmxTb1−xFeO3 system taken for the crystallographic directions [110] and [001] have been investigated. The gyrotropic measurements data are compared to the values of the bond angles θ1 and θ2 calculated in terms of the lattice parameters. The correlation between the crystallographic and optical properties change as a function of composition has been obtained for the system under investigation. ‐The temperature measurements of the gyrotropic properties of SmFeO3 and Sm0.8Tb0.2FeO3 have shown that with temperature rising a change of shape and character of the polar diagrams takes place. The birefringence temperature dependence for Sm0.8Tb0.2FeO3 in the transparency and absorption range has been determined. The results of the study show the existence of the interrelation between the crystallographic, optical and magnetic characteristics and indicate that the temperature range of spin reorientation can be reliably determined from the optical measurements.
Texturtopographie
Authors: Born E.
Published: July 2007

Bei Verwendung der streng monochromatischen Röntgenstrahlung eines Johannsson‐Monochromators registriert die vorgeschlagene Methode die gebeugte Strahlung nicht am Ort ihrer Fokussierung gemäß der Guiniertechnik, sondern im doppelten Abstand, wo der Strahl wieder defokussiert ist. Wenn man z.B. eine polykristalline Metallplatte mit inhomogener Textur untersucht, so erhält man ein Röntgen‐Texturtopogramm mit strenger Zuordnung von Reflexionsort zu Abbildungsort auf dem Film. Voraussetzung ist das Einfügen eines Soller‐Stapels zwischen Präparat und Film zum Aussondern der nicht in der Fokussierungsebene liegenden Strahlen aus dem Beugungskegel.
Dislocation density in InxGa1–xAs films grown on GaAs substrates with intermediate buffer layer InGaAsP of variable composition
Authors: Bolchovityanov J. B. , Bolchovityanova R. I. , Yudaev V. I.
Published: July 2007

InxGa1–xAs films with x = 0.03 and 0.05 were grown from an InGaAsP liquid phase. Because of high value of distribution coefficient of P we have heterojunction GaAsInyGa1–yPzAs1–x–InxGa1–xAs. The influence of Phosphorus atom fraction (Xp) in liquid phase on dislocation density in the top InxGa1–xAs layer was studied. It was found that dislocation density (Nd) as a function of Xp is a curve with some minima. The minima of Nd for substrates of (111) A and (111) B orientations are observed in the different intervals of Xp axis. — The width of Nd minimum is decreased if the substrate is misoriented from the (111) plane. — It was supposed that the clusters exist in the liquid phase. On the basis of this assumption one can explain the influence of substrate position over or under the melt on the film perfection. The diameter of these clusters is estimated to be about 500 Å.
Kinetics of the irregular binary alloys crystallization
Authors: Cherepanova T. A. , Kiselev V. F.
Published: July 2007

With the help of Monte‐Carlo computer simulation method we have investigated the growth of binary crystals having the structure anomally depended on temperature and the liquid phase composition. The dependences of the growth rate and component concentrations in the crystal volume on temperature for different liquid phase compositions were obtained. Kinetic phase diagrams are found here too. A comparison with the results obtained from analytical calculations was also made in this work.
Neutron diffraction analysis of rolling texture and its development in steels with a micro‐duplex structure
Authors: Schreiter U. , Kleinstück K. , Tobisch J. , Mücklich A. , Hötzsch G. , Klimanek P.
Published: July 2007

In this paper first neutronographic texture investigations for two‐phased steels are presented. From each of the phases three complete pole figures were measured. The analysis were carried out by means of the series expansion method. The three‐dimensional orientation distribution functions of all specimens are of tubular shape. For the interpretation of the differences to single‐phased steels the relationships for transformation by Kurdjumov‐Sachs and by Nishiyama were utilized.
Process Induced Crystal Defects in Dislocation‐Free n‐Type Silicon Material
Authors: Fischer W. , Heymann G.
Published: July 2007

This paper describes investigations on process induced crystal defects in n‐type silicon material of both Czochralski‐ and zone‐floating‐techniques (dislocation‐free). The heating and cooling processes, the oxide thickness, mechanical stresses near the diffusion windows, the mask pattern geometry concerning diffusion and the surface concentration of the doping material have been specially investigated. The influence of those technological parameters on the generation of crystal defects in the production of electronic devices is investigated and discussed.
Zur Frage der seitlichen Ionenstreuung bei der Implantation in amorphen und polykristallinen Festkörpern
Authors: Seidowski E. , Mamaev G. I. , Ledovskoj V. P.
Published: July 2007

In der Arbeit werden Gesetzmäßigkeiten für die seitliche Ionenstreuung in amorphen und polykristallinen Festkörpern angegeben. Im Unterschied zu bekannten Lösungen der LSS‐Theorie erlauben diese Gesetzmäßigkeiten die Berechnung der mittleren quadratischen seitlichen Ablenkung der Ionen bei beliebigen Massenverhältnissen von Targetatomen und auftreffenden Ionen in einem breiten Energiebereich, von einigen MeV bis zu Energiewerten nahe der Bindungsenergie der Atome im Festkörper.

Die theoretischen Abschätzungen der mittleren quadratischen seitlichen Ionenablenkung befinden sich in guter Übereinstimmung mit experimentellen Werten verschiedener Autoren.
Dilatometric Studies of Thermal Expansion of Anthracene Crystals
Authors: Jakubowski B.
Published: July 2007

The thermal expansion of anthracene plates cut along the cleavage plane and having different crystalographic orientations was studied by means of a quartz dilatometer. The expansion tensor cross‐section in cleavage plane has been determined. It is shown that there is a correlation between the compressibility tensor orientation and the thermal expansion.
Desymmetrization of OD Structures
Authors: Ďurovič S.
Published: July 2007

It has been shown that the symmetry and structure of individual OD layers may depend on their actual stacking in a (polytypic) OD structure, leading to significant deviations from the ideal OD symmetry. This phenomenon has been called “desymmetrization of OD structures”; its significance for polytypism and for crystallochemistry is discussed.
The OD Structure of Dinitrosylcobalt Chloride, [Co(NO)2Cl]2
Authors: Kuban R.‐J. , Sedlacek P.
Published: July 2007

The OD groupoid family of the structure of dinitrosylcobalt chloride, [Co(NO)2Cl]2, is characterized by the symbol: magnified image

The OD groupoid family of the structure is deduced from the observed arrangement of points in reciprocal space, the symmetry of the intensity distribution and the systematic absences. The structure is built of OD layers of one kind. The determination of the structure of the ordered orthorhombic form (MDO2) has been determined from Weissenberg data obtained by JAGNER and VANNERBERG refined with OD full‐matrix least‐squares methods, based on a total of 150 reflections and anisotropic temperature coefficients. An R value of 0.13 has been obtained. The assumption of JAGNER that the structure is composed of dimers has been found to be justified.
On the Application of Direct Methods in X‐Ray Structure Analysis: Survey on Number and Kind of Solved Acentric Equal Atom Structures
Authors: Messerschmidt J.
Published: July 2007

A statistical analysis of all acentric equal atom structures solved by direct methods and reported in Acta Crystallographica from January 1968 to November 1978 has been carried out. The most frequently applied direct methods programs are the MULTAN, SAP and SHELX. About 80% of all considered structures belong to the space groups P212121 and P 21. Problems with direct methods can arise if the number of the nonhydrogen atoms per asymmetric unit is greater then about 40 and/or the space group belongs to a category in which the definition of the enantiomorph is difficult.
Evolution of Structure in Deformed Single Crystals of fcc Metals at Heating
Authors: Kopezky C. V. , Kokhantchik L. S.
Published: July 2007

The paper deals with conditions resulting in formation of dislocation structures of different types as well as with the change of these structures at subsequent heating which ends in the recrystallization center formation and growth. The measurements were carried out on single crystals of fcc metals. The principal experimental technique was electron microscopy including the annealing of deformed foils directly in the column of electron microscope with accelerating voltage 150 and 1000 kv. Special attention is given to research of the initial stage of recovery in dislocation structures during annealing — the dislocation recovery as the most universal mechanism occurring at any type of structure even when polygonization and recrystallization are hampered. Studies of initial recrystallization stages were mainly carried out while annealing the deformed single crystals of copper. A high degree of local lattice curvature is shown to be a necessary condition for nucleation, and mechanism of the nucleus formation in regions of a high local curvature differs according to the type of the dislocation structure formed during deformation.
Non‐Arrthenius Behaviour and Divacancy Contribution in Self‐Diffusion of 64Cu in Cu
Authors: Krautheim G. , Neidhardt A. , Reinhold U. , Zehe A.
Published: July 2007

The self‐diffusion of 64Cu in Cu was investigated in the high temperature range (1078 to 1348 K), applying the tracer‐standard sectioning technique. For the frequency factor D0 and the activation energy Q0 we found D0 = (0.68)cm2 · s−1 and Q0 = (2.17 ± 0.02) eV. A slight bending of the Arrhenius plot suggests a divacancy contribution to the self‐diffusion of copper. Data sets used in an numerical analysis are in good accord with published results.
Effects of the Crystal Diameter on the Dislocation Density in KCl Crystals Grown by the Czochralski Method
Authors: Inoue T. , Komatsu H.
Published: July 2007

The dependence of dislocation density on the crystal diameter of the Czochralski grown KCl crystals (both pure and Sr doped) was investigated by the method of the etch pit and X‐ray topograph. (1) The dislocation density drastically decreased with the decrease in diameter (D) for small D (D < 2 mm, Fig. 2). (2) The dislocation density in the Sr doped crystal was lower than that of pure component in the diameter examined. (3) Many helical dislocations and dislocation loops were observed in the thin crystals (D ∼ 0.5 mm) of the pure KCl and Sr doped one, respectively, by X‐ray projection topography. These results were discussed in connection with the dislocation generation mechanisms due to thermal stresses or supersaturated point defects.
Thermodynamic properties of strontium tungstate crystal growth from sodium tungstate melts
Authors: Roy B. N. , Handa V. K.
Published: July 2007

Energy (E), enthalpy (ΔHa), entropy (ΔSa) and free‐energy (ΔGa) of activation and the pre‐exponential factor (k0) of the ordinary Arrhenius equation kDl = k0e–E/RT were estimated for diffusion‐controlled crystal growth of SrWO4 from Na2WO4 melts. E increased slightly with increased cooling rates (RT). k0 was parallel to kDl and increased with increasing RT. ΔHa, ΔSa, and ΔGa did not change with the changes in RT and crystallization temperature (T0). The distance (d12), between a diffusing particle and its host necessary for a successful diffusion, was estimated. Such distances slightly increased with T0 and RT.
Crystals of rare‐earth‐ferrous borates
Authors: Maltseva L. I. , Leonyuk N. I. , Timchenko T. I.
Published: July 2007

Crystals of rare‐earth‐ferrous borates (structure of carbonate mineral huntite, space group R 32) were obtained from the solution‐melt with the Bi2O3‐B2O3 base. It was established by the methods of X‐ray structural and chemical analyses that large amounts of Bi from the solution became part of the crystals affecting their solubility, morphology and hardness. Solubility curves for YFe‐, NdFe‐, and ErFe‐borates in the 3 Bi2O3 5 B2O3 melt were plotted. Refinement of crystalline structure of NdFe‐borate showed that bismuth takes up place of rare‐earth ion in the crystal lattice. Parameters of unit cells, density and refractive indexes of the obtained crystals were measured.
The crystallisation of alkaline‐earth metal silicates and titanates from metal chloride melts solubility‐temperatur phase diagram studies
Authors: Packter A.
Published: July 2007

The solubility‐temperature phase diagrams have been analysed for calcium and barium silicate solutions and for calcium, strontium and barium titanate solutions in the metal chloride melts. These systems are typical binary metal salt mixtures with no solid solution or compound formation. Activity coefficients were estimated from log solubility v reciprocal temperature plots and the anion polymerisation numbers were estimated from these coefficients. The metal silicate systems are non‐ideal at silicate mole fractions from 0.1 to 0.8: the solubilities at any temperature are appreciably greater than the ideal values determined from the temperatures and enthalpies of metal silicate fusion: the calcium silicate systems contain upto 50 percent trisilicate chains, while the barium silicate systems contain up to 100 percent trisilicate chains and significant amounts of tetrasilicate chains. The metal titanate systems are practically ideal at titanate mole fractions from 0.01 to 0.3 and possibly upt < 0.6; the solubilities at any temperature are then determined by the temperatures and enthalpies of metal titanate fusion, only.
The X‐ray method for the determination of damaged layer thickness of the Si crystal surface
Authors: Auleytner J. , Bak J. , Furmanik Z. , Maciaszek M. , Saulewicz A.
Published: July 2007

In this paper the X‐ray section topograph method was used for determination of damaged layer thickness of silicon crystal surface. For measurements such reflections should be chosen for which the “margine” effect is very sharp. It was used the fact that in the ranges of strong perturbances the approximation of kinematic theory could be applied.
Coloration, photoconductivity, photo‐ and thermoluminescence of PbMoO4 crystals
Authors: Bollmann W.
Published: July 2007

An absorption band at 435 nm with a half‐value width of 0.57 eV which causes the yellowish colour of PbMoO4 crystals is due to Pb3+ ions. Pb3+ ions are produced by oxidation of the crystals or by incorporation of foreign cations of oxidation state lower than 6 at Mo5+ sites. Usual Pb3+ ion mole fractions are ⪅ 10−7. Annealing of the crystals at low oxygen partial pressure discolours them. Colourless crystals become coloured at low temperatures by ionizating irradiation causing absorption bands at 380 and 575 nm due to Mo5+ ions and at about 990 nm due to an other electronic centre (may be Pb+ or F centre). Heating causes a thermoluminescence connected with disoloration which is finished at room temperature.
Dislocation etching in V3Si
Authors: Gohar I. A. , Kleinstück K. , Krämer U. , Paufler P.
Published: July 2007

Dislocations in as‐grown and in plastically deformed V3Si single crystals have been studied by chemical etching. In as‐grown crystals dislocations are partly arranged in small‐angle boundaries parallel to {001}, {011}, and {112} planes. The total dislocation density amounted to (105−106) cm−2. After plastic deformation at elevated temperatures indications for slip and climb processes were observed. The dislocation density increased to 107 cm−2.
On the reproducibility of the orientation distribution function of texture samples from pole figures (II). Consequences of the limited reproducibility of the ODF — ghost phenomena
Authors: Matthies S.
Published: July 2007

By means of illustrative examples the appearance of ghost phenomena in orientation distribution functions derived by standard methods from pole figure datas is demonstrated in a qualitative manner. It is shown, that as a rule ghost phenomena have no influence on the results of calculations of macroscopic properties of textured samples.
Propagation of acoustic waves in crystals of univalent mercury halides
Authors: Barta Č. , Silvestrova P. M. , Moiseeva N. A. , Pisarevskij J. U. V.
Published: July 2007

Sections through the surfaces of phase and group velocities of propagation of acoustic waves in Hg2Cl2, Hg2Br2 and Hg2I2 were ascertained. The relations between the directions of energy propagation and the directions of phase velocities were also established. It was found that the energy flux deviates from the A‐plane towards the [001] direction. The direction of the smallest velocity of propagation of acoustic waves in the A‐plane was found, too. The results of this study are interesting especially with respect to the practical utilization of some new types of acoustic and acousto‐optic elements.
The crystallization mechanism in high strength glass‐ceramics
Authors: Doenitz F.‐D. , Vogel W.
Published: July 2007

The addition of NiO to a MgOAl2Al2O3SiO2 basic glass has an influence on the phase separation and crystallization mechanism. The differentiation of the components already detectable in the amorphous state continues in the crystallization process of the nickel‐rich glasses. The formation of NiAl‐spinel in the bulk restricts the precipitation of high quartz crystals to the skin. The result is a high strength glass‐ceramic with clearly distinguishable bulk and surface regions.
Random motion of IV‐dipoles in alkali halide crystals forming stable aggregates
Authors: Berg G. , Schmidt R. , Fröhlich F.
Published: July 2007

The formation of higher aggregates of IV‐dipoles consisting of a divalent impurity ion and a cation vacancy is investigated by the simulation of their random motion in a model lattice at different annealing temperatures. An interaction potential between the sink for the dipoles and the dipole in the lattice is assumed. Additionally a decay of the sink is allowed. The results show, that already two dipoles (i.e. a dimer) from a stable aggregate. This is in agreement with theoretical calculations of the equilibrium concentrations of higher aggregates and the results of kinetic measurements of dipole aggregation. The reason is the relative high binding energy of dipoles in alkali halide crystals.
Double crystal diffractometry for the characterization of targets for laser fusion experiments
Authors: Förster E. , Goetz K. , Zaumseil P.
Published: July 2007

The application of a double‐crystal diffractometer for the production of X‐ray Schlieren topographs is described. The experimental arrangement is optimized on the basis of a wave‐optical description for the investigation of shell targets for laser fusion experiments. The accuracies achieved at the wall thickness measurement of 0.01 … 0.1 μm depending on the series of wall materials and the effort of evaluation fulfil the plasma physical requirements. This opens an important new field of application for the double‐crystal diffractometer.
Structure perfection of some molecular crystals grown from the melt
Authors: Naumowicz P. , Szarras S.
Published: July 2007

Single crystals of anthracene, naphthalene, phenazine and anthracene sym. trinitrobenzene (TNB) were examined using X‐ray topography. Low‐angle boundaries were observed and misorientation vectors of adjacent mosaic blocks have been estimated. Using an X‐ray camera with oscillating film dislocation density in crystals has been evaluated. Anthracene‐TNB crystals showed a much higher structure perfection than the other crystals.
Investigations for Sn diffusion in Pb1−xSnxTe and PbTe
Authors: Siche D. , Ermisch W.
Published: July 2007

By annealing Pb1−xSnxTe and PbTe isothermally in a quartz ampoule Sn diffused from Pb1−xSnxTe into PbTe. The profiles obtained have been investigated by means of an electron beam microanalyser, and the coefficients of diffusion have been determined at various temperatures. The diffusion of Sn can be explained by the expressions: DPbSnTe = 1.5 · 10−1 exp (−1.8 eV/kT) cm2 s−1 (0,14 < x < 0,18) DPbTe = 5,5 · 10−4 exp (−1.5 eV/kT) cm2 s−1.

N‐type layers are observed at the surface of Pb1−xSnxTe specimens.
A linear relativistic method for the calculation of band structure in transition metals with results for Au
Authors: Ziesche P. , Wonn H. , Fleck U.
Published: July 2007

With a linear relativistic method we calculated the band structure of gold. A comparison with the results of a RAPW calculation shows that the deviation is about 3%. The effort of computational time is for the linear method considerably smaller than for the RAPW method.
On the quaternary NGa‐NAl‐NAs‐NGe phase diagram
Authors: Geselle B. , Herrmann F. P. , Wagner G.
Published: July 2007

It was stated that the thickness of Ge‐doped GaAs‐ and AlxGa1−xAs epitaxial layers, respectively, grown by equilibrium cooling from a gallium rich flux, varies with the Ge concentration in the liquid phase. This relationship was applied to calculate an quaternary Ga‐Al‐As‐Ge phase diagram by means of the law of mass action.
Dissociation and Redistribution of the Point Defects in Sillicon under External Elastic Field
Authors: Milevskii L. S. , Tkacheva T. M.
Published: July 2007

[Russian Text Ignored].
Influence of stacking disorder on the electronic properties of layered semiconductors
Authors: Maschke K.
Published: July 2007

It is shown that stacking disorder in layered semiconductors leads to a localization of the electronic wavefunctions over a finite number of layers. The electronic transport across the layers is described in terms of a hopping model. The experimentally observed strong anisotropy of the de‐conductivity for low temperatures is explained as a consequence of the stacking disorder.
X‐ray heating chamber investigations of reforming Pt‐Al2O3 catalysts
Authors: Richter K. , Bornmann P.
Published: July 2007

Model catalysts with increased Pt content and commercial catalysts have been tested in an X‐ray heating chamber at different temperatures and in various fluids (O2, N2, N2/H2 and Ar) at atmospheric pressure. In an air atmosphere and at temperatures between ambient and approx. 850 K, the Pt crystallites are subjected to superficial oxidation, sintering starts at approx. 850 K. In a hydrogen atmosphere, an increase in temperature at first results in the formation of crystalline Pt particles having a degree of crystallinity of 100% (error range 5%). Depending on the kind of sample and beginning at approx. 700 K, a Pt hydride phase which is stable in H2 only and has a lattice constant of a = 3.875 Å is formed later on.

Furthermore, conclusions for the evaluation and interpretation of X‐ray measurements of catalysts are drawn.
Domain structure in main crystallographic planes of orthoferrites at spin reorientation
Authors: Ges' A. P. , Fedotova V. V.
Published: July 2007

The behaviour peculiarities of the domain structure of the single crystal samarium‐terbium‐erbium and samarium‐terbium‐thulium orthoferrites in the spin reorientation range in three crystallographic planes (001), (110) and (100) are investigated. In the (001)‐plane the temperature‐induced bubble domain lattice formation is observed. The formation kinetics of these domains is similar to the process of nucleation and that of growth with spontaneous crystallization. In the (110) plane the inclined domains formation is noted. The canting angle depends on temperature at spin reorientation. The values of remagnetization fields are measured as a function of temperature in the indicated crystallographic planes. From the measured changes of the domain structure the temperature dependences of the first anisotropy constant and the domain wall density are determined.
A Study of Electrical Conductivity in Concentrated Solid Solutions ca1−xLnxF2+x (Ln = La, Gd, Er, Y)
Authors: Švantner M. , Mariani E. , Fedorov P. P. , Sobolev B. P.
Published: July 2007

This work completes our previous results on the measurement of electrical conductivity in fluorite solid solutions Ca1‐xLnxF2+x (MARIANI et al.), ŠVANTNER et al.) and gives new results for Ca1‐xGdxF2+x and Ca1‐xErxF2+x. The main characteristic of the measured ln σ vs 1/T dependences in an increase of electrical conductivity and decreases of activation energy with increasing concentration of LnF3. The preexponential terms in the Arrhenius formula for electrical conductivity are constant for x > 0.01. In the interpretation of measured results the existence of regions with high concentration of defects is assumed in agreement with structural views.
On crystal chemistry and morphology of extended organic molecules
Authors: Follner H.
Published: July 2007

The present paper is concerned with the morphology and crystal structure of extended organic compounds in the space group P 21/c. In the structures with molecules in general position (Z = 4) the longitudinal axis of all molecules run parallel to a (h0l)‐plane. The molecule arrangements are based on four different structure types. The planes through the molecule axis contain a) 21‐axis and symmetry centres (l = 2n), b) 21‐axis or symmetry centres (l = 2n + 1) and c) respectively d) no symmetry element (l = 2n resp. 2n + 1). In the last two cases the net plane distances are to be halved. As in P 21/c the a‐und c‐axis are not set, one can confine oneself to the examination of the net planes (102), (202), (204), and (404). In the cases of a) and b), only certain morphological lattices appear, which distinguish themselves through additional translations in three‐dimensional space resp. in the projections. In the cases of c) and d) there are also found morphological lattices which generate additional “morphological extinctions” (consequently possessing a higher symmetry than the generating space group), but which contain no translationally higher symmetry. (h0l)‐faces, to which the molecule axis run parallel, appear with preference on crystals. As a rule the first two and the last two cases can be differentiated on account of the position of the (h0l)‐faces in the Donnay‐Harker series. Some examples will show that the morphological lattice can be preserved through Fourier transformation of crystal morphology.
Solution‐mediated polymorphic transformation of stearic acid
Authors: Wellner E. , Garti N. , Sarig S.
Published: July 2007

Polymorphic transformations of stearic acid in their crystallization solutions have been studied. When stearic acid crystals were left in the ethanolic saturated mother liquor, the B‐form modification was obtained throughout the whole process. In n‐hexane and benzene during the first 2–3 hours, the C‐polymorph was the predominant form, later transformed progressively into the B‐form, so that towards the end of the experiment the whole precipitate was in the B‐form. The proposed explanation is that the transformation is due to dissolution caused by thermal fluctuation in the bath, and subsequent precipitation. The dissolution and reprecipitation was followed up by micro photographs. In the presence of Span 60, only C form was obtained in all the solvents. – As a result of this study it is suggested to pay attention to possible solution‐mediated polymorphic transformations of the crystallized material which may cause a misleading interpretation of the factors affecting the crystallization of the fatty acid.
Impurity States in CuInSe2
Authors: Neumann H. , Nowak E. , Kühn G.
Published: July 2007

The impurity states occurring in CuInSe2 crystals after annealing in an atmosphere of Se and in‐diffusion of In are determined by electrical measurements. The experimental results suggest the conclusion that the shallow donor with an ionization energy of about 10 meV is due to Se vacancies, the shallow acceptor with about 35 meV due to In vacancies, and the acceptor with about 100 meV due to Se interstitials. The deep acceptor with an ionization energy of about 400 meV is assumed to be due to Fe2+ substituted on In sites.
A comparative arima analysis of the 111 series of the makridakis competition
Authors: Lusk Edward J. , Neves Joao S.
Published: July 2007

The 111 series of the Makridakis competition are used to address a number of questions pertaining to use of the Box–Jenkins technique. The ARIMA models developed are compared to the ARIMA models developed independently by Andersen for the Makridakis competition. The time required to perform the analysis for each series is discussed in terms of model complexity. Forecast accuracy, measured as the MAPE for the one step ahead forecast, is discussed for different series lengths.
Conditional distribution analyses of probabilistic forecasts
Authors: Yates J. Frank , Curley Shawn P.
Published: July 2007

Probabilistic forecasts have good ‘external correspondence’ if events that are assigned probabilities close to 1 tend to occur frequently, whereas those assigned probabilities near 0 tend to occur rarely. This paper describes simple procedures for analysing external correspondence into meaningful components that might guide efforts to understand and improve forecasting performance. The procedures focus on differences between the judgements made by the forecaster when the target event occurs, as compared to when it does not. The illustrations involve a professional oddsmaker's predictions of baseball game outcomes, meteorologists' precipitation forecasts and physicians' diagnoses of pneumonia. The illustrations demonstrate the ability of the procedures to highlight important forecasting tendencies that are sometimes more difficult to discern by other means.
Regression forecasts when disturbances are autocorrelated
Authors: Dielman Terry E.
Published: July 2007

A Monte Carlo simulation is used to study the quality of forecasts obtained from regression models with various degrees of autocorrelation present in the disturbances. The methods used to estimate the model parameters include least squares, full maximum likelihood, Prais‐Winsten, Cochrane‐Orcutt and Bayesian estimation. Results indicate that the Cochrane‐Orcutt method should be avoided. The full maximum likelihood, Prais‐Winsten and Bayesian methods are relatively more efficient than least squares when the degree of autocorrelation is high (greater than or equal to 0.5) and show little efficiency loss when the degree is low. These results hold for both trended and untrended independent variables.
Forecasting contemporaneous aggregates and the combination of forecasts: The case of the U.K. monetary aggregates
Authors: Mills Terence C. , Stephenson Michael J.
Published: July 2007

A number of papers in recent years have investigated the problems of forecasting contemporaneously aggregated time series and of combining alternative forecasts of a time series. This paper considers the integration of both approaches within the example of assessing the forecasting performance of models for two of the U.K. monetary aggregates, £M3 and MO. It is found that forecasts from a time series model for aggregate £M3 are superior to aggregated forecasts from individual models fitted to either the components or counterparts of £M3 and that an even better forecast is obtained by forming a linear combination of the three alternatives. For MO, however, aggregated forecasts from its components prove superior to either the forecast from the aggregate itself or from a linear combination of the two.
Experience in combining subjective and quantitative forecasts of open market rates
Authors: de Bragança Pereira Basilio , Coqueiro Ricardo Cesar Otero , Perrota Antonio Horácio Vincente
Published: July 2007

This paper presents a method of combining subjective information from open‐market operators with results from a time‐series forecasting model. Empirical results of forecasts for interest rates of bank reserves are presented.
Judgmental adjustment of earnings forecasts
Authors: Wolfe C. , Flores B.
Published: July 2007

Earnings forecasts have received a great deal of attention, much of which has centered on the comparative accuracy of judgmental and objective forecasting methods. Recently, studies have focused on the use of combinations of subjective and objective forecasts to improve forecast accuracy. This research offers an extension on this theme by subjectively modifying an objective forecast. Specifically, ARIMA forecasts are judgmentally adjusted by analysts using a structured approach based on Saaty's (1980) analytic hierarchy process. The results show that the accuracy of the unadjusted objective forecasts can be improved when judgmentally adjusted.