bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capture and distribution of impurities in stockbarger grown garnets
Authors: Petrosyan A. G. 
Published: July 2007

AbstractDistribution of Nd3+ ions in garnet single crystals grown from a melt by Stockbarger technique is presented. Possible factors which can influence the segregation coefficient are discussed. Among those three principal mechanisms are considered: (a) capture of impurity ions by a foreign phase, (b) evaporation and (c) surface processes at the interface.
Zur Ausbreitung des Lichtes in Kalomel‐Einkristallen
Authors: Trnka J. , Barta Č. , Dolejší J. 
Published: July 2007

AbstractEs wurden Beziehungen für Berechnung der Ausbreitungsrichtung des Lichtes in doppelbrechenden einachsigen Kristallen für eine beliebige kristallographische Orientierung des Kristalls und für einen beliebigen Einfallswinkel des Lichtstrahls in der Ebene des Hauptschnittes abgeleitet. Für Kalomel (Hg2Cl2) wurden die Brechungswinkel des ordentlichen und außerordentlichen Strahls für Einfallswinkel von +90° bis −90°, für Winkel der kristallographischen Orientierung von 1° bis 90° und für Wellenlängen des Lichtes von 380 nm bis 16 μm berechnet.
The precipitation of alkaline‐earth metal molybdate powders from aqueous solution. Crystal numbers, final morphology and sizes
Authors: Packter A. 
Published: July 2007

AbstractThe precipitation of barium, strontium and calcium molybdates was studied from neutral equivalent solutions of concentrations from 0.0004 to 0.4 M at 25 °C. Crystal growth started after induction periods; the precipitiations were heterogeneously nucleated at low supersaturations and homogeneously nucleated at medium to high supersaturations. Barium molybdate was precipitated as tetragonal bipyramids, strontium molybdate generally as prisms and calcium molybdate as platelets. Crystal numbers at medium to high supersaturations increased with increasing inital metal molybdate concentrations according to the relation,

The final crystal lengths in this range than decreased from maximum values (at the critical concentrations) with increasing initial metal molybdate concentrations according to the relation.

Generally, for precipitation from solutions at any concentration, larger crystals were obtained in the precipitates of the salt of higher solubility.
Chemische Bindung und Struktur von Halbleitern und Isolatoren
Authors: Hübner K. 
Published: July 2007

AbstractModerne semiempirische Substanz‐ und Strukturtheorien sind sehr nützlich für die Untersuchung chemischer Trends von Materialeigenschaften von Halbleitern und Isolatoren. Auf der Grundlage des Konzeptes der Ionizität gemischt ionogen‐kovalenter chemischer Bindungen werden chemische Trends von ausgewählten energetischen, elektrischen und elastischen Eigenschaften beschrieben. Der Ionizitätsparameter, der aus der statischen elektronischen Dielektrizitätskonstante oder aus Valenzbandspektren ermittelt werden kann, wird in Modelle für verschiedene Effekte (z.B. die chemische Verschiebung elektronischer Bindungsenergien) eingebaut. Auf diese Weise wird chemische Information explizit berücksichtigt und gute Übereinstimmung mit experimentellen Ergebnissen erreicht. Mit der Ionizität und verknüpften Parametern wird die Abgrenzung vier‐ und sechsfach koordinierter Kristallstrukturen, die relative Stabilität der Wurtzit‐ gegenüber der Zinkblende‐Struktur und das Problem unterschiedlicher Bindungswinkel in verschiedenen SiO2‐Modifikationen untersucht. Eine Erweiterung dieses Konzeptes im Rahmen der Pseudopotentialtheorie führt zu einigen interessanten Schlüssen bezüglich struktureller Unordnungseffekte in amorphen Halbleitern.
A new deduction of a complete list of OD‐groupoid families for OD‐structures consisting of equivalent layers
Authors: Fichtner K. 
Published: July 2007

AbstractThere are 400 OD‐groupoid families. If OD‐groupoid families not permitting disorder are excluded, 377 families remain in the list. This number reduces further to 363, if enantiomorphic pairs of OD‐groupoids are generally put in one and the same OD‐groupoid family. Misprints in previous lists of these 363 families are corrected.
Untersuchungen zu den Stoffübergangsprozessen an frisch gefälltem Strontiumsulfat in gemischten Lösungsmitteln (II)
Authors: Winzer A. 
Published: July 2007

AbstractDie Stoffübergangsprozesse nach der Fällung von SrSO4 aus gemischten Lösungsmitteln (Wasser‐Methanol, Äthanol, Aceton) resultieren aus der relativ hohen Geschwindigkeit der Ostwald‐Reifung, der Rekristallisation und des heterogenen Isotopenaustausches. Dies ist auf die bei der Fällung aus gemischten Lösungsmitteln größere Oberfläche sowie teilweise amorphe Struktur des SrSO4 zurückzuführen. Durch Messungen zur Adsorption von 89Sr2+(solv.) an Aktivkohle (KO) sowie zum heterogenen Isotopenaustausch an gealtertem SrSO4 in Abhängigkeit von der Methanolkonzentration in gemischten Lösungsmitteln konnte gezeigt werden, daß die Desolvatation der Ionen bzw. die Umorientierung der Solvatmoleküle für die Geschwindigkeit der Stoffübergangsprozesse an Phasengrenzflächen von Ionenkristallen von Ionenkristallen von Bedeutung sind.
Growth of cobalt single crystals by the Electron beam floating‐zone method
Authors: Hayashi S. , Ono S. , Komatsu H. 
Published: July 2007

AbstractCo single crystals of striation‐free were grown easily by the electron‐beam floating‐zone melting. For these crystals, observations on dislocations were carried out. Slight preferred direction of grown crystals were discussed on the basis of the local step structure on the crystal surface.
Zum Einfluß des Primärionenstrahlprofils bei der Monolagenanalyse mittels der Methode SIMS
Authors: Storbeck F. 
Published: July 2007

AbstractEs wurde der Einfluß der Form des Primärionenstrahls auf die Sekundärionenströme bei der Methode SIMS behandelt. Damit konnten die Resultate von Benninghoven zum Abbau von Monolagen auf den in einigen SIMS‐Anlagen vorliegenden Fall verallgemeinert werden, daß das Primärionenstrahlprofil ungleichförmig, d.h. daß die Stromdichte im Bestrahlungsfleck nicht konstant ist. Ferner wurden für die Aufnahme von Tiefenprofilen mittels feststehendem Primärionenstrahl ungleichförmigen Profils eine analytische Formel angegeben, mit der der „Krater‐Effekt”︁ rechnerisch eliminiert werden kann. Anhand von experimentellen Kurven, die man bei der Untersuchung der Oxydation einer (100)‐Cr–Ni–Stahl‐Oberfläche mittels SIMS erhält, wurde beispielhaft gezeigt, wie eine quantitative Analyse durchzuführen ist.
Zur Kenntnis des lithium‐neodym‐polyphosphates LiNd(PO3)4
Authors: Bohm J. , Schalge R. , Schultze D. , Waligora C. 
Published: July 2007

AbstractLiNd(PO3)4 kristallisiert aus einer schmelzflüssigen Lösung in LiPO3 in Gestalt von Plättchen parallel (100) oder von prismatischen Säulen parallel [001] mit pseudo‐rhombischer Tracht. ‐ Die Kristalle sind optisch zweiachsig positiv mit den Hauptbrechungsindizes nα = 1,6665; nβ = 1,6125; nγ = 1,6195 ± 0,0005 (λ = 589,3 nm) und einem optischen Achsenwinkel 2Vγ = 43° maximale Doppelbrechung δn = 12,7 · 10−3, Doppelbrechung auf (100) δn,/ia = 5,9 · 10−3.
On the distribution of growth directions of silver and other F.C.C. single crystals from the melt
Authors: Hayashi S. , Echigoya J. 
Published: July 2007

AbstractThin single crystals of pure Ag, its dilute alloys, Ni – 10 ˜ 60 wt.% Co and Fe – 35 wt.% Ni alloys were grown by the Bridgman method. A preference of growth directions of these crystals changes from the <111>direction towards <100>with increasing growth rate or alloying effect. These results are discussed from a characteristic of nucleus interfaces.
Einfluß hoher Versetzungsdichten auf die Kennliniencharakteristik von Dioden
Authors: Richter H. , Heymann G. 
Published: July 2007

AbstractAus n‐leitenden Si‐Kristallen mit niedrigen Versetzungsdichten (EPD einige 103 cm−2) und durch plastische Deformation erzeugten hohen Versetzungsdichten (EPD einige 109 cm−2) wurden Dioden gefertigt. Über die Ermittlung dr Kennliniencharakteristik und die Lebensdauer der Minoritätsladungsträger wird die Wirkung der in hoher Dichte auftretenden Versetzungen untersucht. Bei der Probenpräparation wurden Orientierungsbeziehungen ausgewählt, durch die in 1. Näherung ein Durchstoßen des p, n‐Überganges durch die Versetzungen vermieden wird.
Zur quantentheoretischen Berechnung von Aktivierungsenergien für den Stoffübergang an Phasengrenzflächen von Ionenkristallen (IV). Zur radiochemischen Bestimmung und quantentheoretischen Berechnung von Aktivierungsenergien für den Stoffübergang an den Kristallflächen des NaCl
Authors: Winzer A. 
Published: July 2007

AbstractES wird gezeigt, daß zwischen der Aktivierungsenergie für den Stoffübergang an der jeweiligen Kristallfläche von Ionenkristallen und der Frequenz der Phonenen (longitudinal optische) eine direkte Proportionalität besteht, wobei wiederum als Proportionalitätskonstante das Plancksche Wirkungsquantum gefunden wurde. Damit konnte nachgewiesen werden, daß die in verschiedenen Zeitintervallen gemessenen unterschiedlichen Aktivierungsenergien für die Stoffübergangsprozesse an Phasengrenzflächen von Ionenkristallen auf das flächenspezifische Wachstum der Kristalle zurückgeführt werden können. So wurde mit NaCl‐Kristallfraktionen, die mechanisch beansprucht wurden (gemahlen und gesiebt) und somit relativ viele {111}‐ bzw. {110}‐Flächen enthielten, experimentell eine Aktivierungsenerhalten, die mit dem quantentheoretisch berechneten Wert übereinstimmt, wenn die Frequenz der Phononen für diese Ausbreitungsrichtung in die abgeleitete Gleichung eingesetzt wurde. Auch bei NaCl‐Kristallfraktionen, die nahezu ausschließlich Würfelflächen enthielten, konnte diese Beziehung bestätigt werden. Dies ist ein weiterer Hinweis dafür, daß bei Stoffübergangsprozessen an Phasengrenzflächen von Ionenkristallen quantenmechanische Gesetzmäßigkeiten von Bedeutung sind.
Herstellung und ausgewählte physikalische Eigenschaften von ZnSiP2
Authors: Becherer H. , Buhrig E. , Hein K. , John M. , Kirsten P. , Schneider H. A. , Siegel W. , Winkler K. 
Published: July 2007

AbstractUndotierte ZnSiP2‐Kristalle, die nach verschiedenen Methoden gezüchtet wurden (Gasphasentransport, Lösungszüchtung), zeigen teilweise beträchtliche Differenzen in ihren physikalischen Eigenschaften. Ziel der Arbeit ist, es, Zusammenhänge zwischen der Herstellung von ZnSiP2, der Qualität der eingesetzten Ausgangsstoffe und den physikalischen Eigenschaften der halbleitenden Verbindung aufzuzeigen. Messungen des Hall‐Effektes, der Leitfähigkeit, der Lumineszenz und der Protonenrückstreuung ergaben Informationen über die Perfektion und die Homogenität der Kristalle sowie über Störstellen und Rekombinationszentren, die für die verschiedenen Züchtungsmethoden charakteristisch sind. Der Einfluß der Dotierung durch verschiedene Elemente auf die Eigenschaften von lösungsgezüchteten ZnSiP2‐Kristallen wurde untersucht.
A simple scheme for describing the motion of dislocations in silicon
Authors: Fischer A. 
Published: July 2007

AbstractThe velocity of dislocations in silicon single crystals was investigated in dependence on temperature and stress. A simple scheme for the description of dislocation motion valid in the temperature range of 650 to 850 °C and the stress range of 0.2 to 5.0 kp/mm2 was derived.
Metallurgy of bronze‐process A‐15 superconducting composites
Authors: Livingston J. D. 
Published: July 2007

AbstractSeveral aspects of the metallurgy of multifilamentary composites of Nb3Sn, V3Ga, and other A‐15 superconductors produced by the bronze process are reviewed. Among the factors discussed are phase diagrams, reaction kinetics, alloying effects, and microstructure‐properties relations.
Investigations on nitride layer formation at the iron surface during gas nitriding
Authors: Jentzsch W.‐D. , Böhmer S. 
Published: July 2007

AbstractThe morphology of the nitride layer forming at gas nitriding can decisively be influenced by the pretreatment of the surface. At a temperature of about 550 °C an activated surface very swiftly covers with iron nitrides. After passivating of the surface the nitride formation and the geometrical order of the nitride layer are determined by the heating rate. At high heating rates the formation of iron nitrides is localized to a few spots and the extension of the nitride layer proceeds by the growth of these spots. At low heating rates the surface is reactivated by the reducing gas before reaching the nitriding temperature. By further investigations is shown that nitriding of the surface starts with the formation of γ′‐nitrides. ϵ‐Nitrides occur in the further process of nitriding as a second layer on the γ′‐phase.
Growth of sapphire by the kyropoulus method
Authors: Perner B. , Kvapil Josef , Stránský V. , Kvapil Jiři 
Published: July 2007

AbstractSingle crystals of leuko‐sapphire (α‐Al2O3) are grown from the melt by an improved Kyropoulos technique using Mo or W crucibles. The influence of the temperature field on the structural and optical quality has been studied. Best results were obtained when heat losses from crystal and melt are minimized.
Switching Behaviour of Pb5Ge3O11 Single Crystals
Authors: Blumberg H. , Kürsten H. D. 
Published: July 2007

AbstractSingle crystals of lead germanate have been grown by Czochralski method. Hysteresis and switching pulses could only be measured after treating the crystal samples at elevated temperature and electrical a.c. field. Hysteresis is strongly frequency dependent. We observed the motion of the domain walls in polarized light simultaneously. The hysteresis loop is distorted at elevated temperature because of electric conductivity of the crystals. Temperature dependence of electric conductivity has been measured.
EPR and Optical Absorption Spectra of Cr3+ Ions in Lithium Sulphate Single Crystals
Authors: Alybakov A. A. , Bujko V. M. , Sharsheev K. 
Published: July 2007

AbstractOptical absorption and EPR spectra of Li2SO4 · H2O crystals doped with Cr3+ are studied at liquid nitrogen temperature. The bands are found in absorption spectra with maxima about 17000, 23 800 and 37 200 cm−1, assigned to the 4A2 → 4T2, 4A2 → 4T1 and 4A2 → 4T1 (4P) transitions, respectively. The crystal field theory parameters were determined and appeared to be as follows: Dq = 1700 cm−1, B = 667 cm−1, C = 3002 cm−1.The lines resulting from Cr3+ ions are found in EPR spectra. All lines are doublets, which is indicative of presence of two magnetically unequivalent centre positions, and have the hyperfine structure resulting from interaction of the unpaired electron spin with Cr53 isotope nucleus. Centres are oriented in such a way, that z‐axes, corresponding to two centre positions, are situated at both sides of a‐axis at an angle of about 3°. Spin Hamiltonian parameters were found as follows: gx = 1.985, gy = 1.984, gz = 1.988, D = 0.130 cm−1, E = 0.016 cm−1, |A| = 17.8 · 10−4 cm−1.
In‐situ Deformation of Polymers in the HVEM
Authors: Michler G. H. 
Published: July 2007

AbstractThe advantages of the High Voltage Electron Microscopy for investigations of the deformation mechanisms in polymers are mentioned. Amorphous one‐ and tow‐phase polymers, showing microprocesses of deformation and fracture in close connection with crazing, are investigated in detail. In the glassy polymers the structure of the crazes can be very different in dependence on the polymer morphology, the testing parameters, and others. Semi‐quantitative relationships between the microprocesses, the fracture toughness, and the polymer morphology could be obtained for high‐impact polymers.
Temperature dependence of secondary electron emission from SiO2‐layers
Authors: Fitting H.‐J. 
Published: July 2007

AbstractBy means of a “random walk model” the escape depths of secondary electrons (SE) can be obtained as a consequence of interaction with LO‐phonons. The measured temperature dependence of the SE‐yield leads to a high energetic LO‐mode with ħω ⋍ 140 meV in amorphous SiO2 influencing dominantly the electronic slowing down process.
Investigation of PbTiO3 crystal lattice defects by transmission electron microscopy
Authors: Dobrikov A. A. , Presnyakova O. V. , Zaitsev V. I. , Prisedskii V. V. , Pan'ko G. F. 
Published: July 2007

AbstractThe investigation of PbTiO3 single crystal structure was carried out by the method of transmission electron microscopy (TEM). It is shown that the following types of defects are observed: ferroelectric 90°‐and 180°‐domain boundaries, dislocations and their complexes, and planar defects.
Kinetics of dissolution of BaF2 crystals
Authors: Smirnov A. E. , Urusovskaya A. A. 
Published: July 2007

AbstractKinetics of dissolution of BaF2 crystals in aqueous solutions of HNO3 and HCl acids have been studied for the different acid concentrations in the temperature interval 20–100°C. It is established that this process is diffusion controlled. Activation energy is constant, but pre‐exponential factor is dependent on the concentration of the acid.
Etching of CaF2 single crystals in silica gels
Authors: Patel A. R. , Kotak M. D. 
Published: July 2007

AbstractEtching of {111} cleavage faces of CaF2 crystals in aqueous solution of 50% HCl is carried out in citric acid set silica gel, and the kinetics of growth of etch pits at the sites of dislocations is investigated as a function of temperature, time of etching and height of gel column above the crystal surface. It is observed that the transient period required to initiate etch pit at the sites of a dislocation decreases (1) at particular temperature, with a decrease in gel height, and (2) for a particular gel height, with an increase in the temperature of etching. It is also observed that the morphology of dislocation etch pits remains triangular irrespective of the gel height and the temperature of etching. The results are compared with those of solution etching and discussed.
Dielectric relaxation in nematic, smectic A and C phases in the MHz region
Authors: Kresse H. , Wiegeleben A. , Demus D. 
Published: July 2007

AbstractThe dielectric properties of four 4‐n‐alkyloxyphenyl 4‐n‐alkyloxybenzoates with nematic, smectic C and partly additional SA phases were investigated. In 2 substances for ϵ′ reproducible values also in the smectic phases resulted allowing to conclude on a good orientation in the samples. In all 4 substances the dielectric relaxation in the MHz region was measured and the respective activation energies were determined. The molecular mobility in the SC phases is higher than in the SA phases, however comparable with that of the nematic phases. In all 3 phase types a single relaxation mechanism exists, which is explained as rotation of the molecules around a short axis.
Investigation of the interaction of quartz with H2 under supply of mechanical energy (I)
Authors: Hennig H.‐P. , Ebert I. , Steinike U. , Geissler H. , Kretzschmar U. 
Published: July 2007

AbstractThe gas molecules absorbed during mechanical activation of quartz in a H2 atmosphere are situated as well as the formed E′ centres in the amorphous ranges. The concentrations of the E′ centres are about one order of magnitude less after activation in H2 than after an activation in Ar. Hence and because of the existence of a proton doublet (splitting of about 73 G) in the EPR spectra a chemical interaction of a part of the absorbed H2 molecules with quartz is concluded.
On the characterization of electrically active inhomogeneities in semiconductor silicon by charge collection at schottky barriers using the SEM‐EBIC (II). Contrast due to defects
Authors: Kittler M. 
Published: July 2007

AbstractThe influence of the control variables (E0, Ib, Ur) as well as the semiconductor parameters (ϱ, L) on the defect contrast of direct irradiated Schottky barriers is investigated. The resolution of the subsurface regions is enhanced by increasing the primary beam energy E0. The sharply imaged region can be extended into the depth of the crystal by applying a reverse bias Ur. Contrast width broadenings are observed in high‐ohmic material, if increasing the beam current Ib, which may be annuled by switching on Ur. Against the generally held view the diffusion‐induced contrast width broadening of defects (or parts of them) located outside the depletion layer was found as an extremely small fraction of the diffusion length L. Thus in rough approximation the contrasts can be interpreted as a superposition of the in general club‐shaped generation volume and the defect shape.
A model of the effect of R.T. preageing on the nucleation of η′‐precipitation in Al‐Zn‐Mg alloys
Authors: Radomsky M. , Löffler H. , Lendvai J. , Ungár T. , Kovács I. 
Published: July 2007

AbstractThe effect of R.T. preageing on the precipitation of the η′ particles was investigated in two Al‐Zn‐Mg alloys. The results are explained by a model according to which during or immediately after the quench to RT vacancy, or vacancy‐zinc clusters (nuclei) are formed. The heterogeneous formation of η′ particles during the artificial ageing takes place at the nuclei or at over‐critical size GPZ in the more concentrated alloy or at solute‐rich regions left behind after the complete reversion of GPZ in the alloy with lower Zn concentration.
The interaction of oxygen with the iron (111) surface, mainly studied by AES
Authors: Müsig H.‐J. , Arabczyk W. 
Published: July 2007

AbstractThe cleaned surface was oxidized by means of pure oxygen at a pressure of 3 × 10−6 – 3 × 10−3 pa and at temperatures of 300 K, 370 K, and 620 K. The Auger peaks of high energy (for oxygen at 510 eV and for iron at 703 eV) were used for the quantitative determination of the oxygen coverage on the iron surface. The experimental results on the change of oxygen coverage as a function as a function of the dose are interpreted by means of a theoretical model and provided definite informations about the bonding state of the adsorbate. In the lower energy part of the Auger spectrum there appear peak shape modifications during oxidation. These observations allow us to suppose that in the process of oxidation there are in action two kinds of chemical bonding of oxygen with iron differing by density of states in the valence band.
The structure and electrical resistance of thin scandium films (II). F.C.C.–lattice phase observed in films obtained in a vacuum of 10−8 Torr
Authors: Loboda V. B. , Protsenko I. E. 
Published: July 2007

AbstractPhase composition of the Sc‐films up to 200 Å thick obtained in a vacuum of 3 · 10−8 Torr, condensation rate being ω ⋍ 1 to 6 Å/s and ω ⋍ 40 å/s up to 10−7 Torr, have been studied by an electron‐diffraction examination. A phase with an f.c.c.‐lattice and a lattice parameter a = 4.76 to 4.80 ± 0.01 Å 0.01 Å is observed in films d ≲ 60 Å thick, whilst with films having a thickness d ≳ 90 Å a h.c.p.‐phase is characteristic for solid specimens. Two‐phase composition is observed in an interjacent interval of thicknesses.An analysis performed permitted to conclude that the f.c.c.‐phase observed is a ScHx‐hydride forming during the post‐condensation delay time on a basis of a poly‐morphic modification.
Information on the early decomposition behaviour in Al‐Zn(6)‐Mg(X) alloys by an analytical description of isothermal resistivity curves
Authors: Fabian H.‐G. 
Published: July 2007

AbstractBased on a theoretically derived expression for the extra‐resistivity resulting from the formation of GP‐Zones

equation image

isothermal resistivity measurements with Al‐Zn(6 at.%)–Mg(0.81; 1.73 at.%) alloys were analysed. A comparison of both expressions d(ln ϱex)/dt and d(ln f)/dt yields statements on the early stage of decomposition behaviour, especially, whether up to a considered time point size growth happened. The evaluated examples lead to the conclusion that size growth is most probably to exclude up to the time point of 4T.The Ta‐dependence of the maximum value of extra‐resistivity is explained by an equilibrium distribution of bigger particles of a smaller number at higher aging temperatures, of smaller particles of a greater number at lower aging temperatures and by the assumption, that the amount of solute atoms inside the GP‐zones is decreasing with rise of Ta.