bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of dendritic side‐branches coarsening under isothermal conditions
Authors: Fedorov O. P. , Ovsienko D. E. 
Published: January 2007

AbstractThe process of dendritic branches transformation of succinonitrile and some other organic substances has been studied under the isothermal holding of two‐component melt. The dendritic branches have been shown to be separated from the steam in the specimen with the thickness comparable with the diameter of the dendrite. Dendritic structure coarsening observed in the bulk specimen is not associated with the separation of the branches. In the region of the concentration gradient the dendritic growth has been shown to result in partial dissolution of as‐crystallized material under the isothermal holding after the end of crystallization. This effect seems to result from the diffusionless growth in the two‐phase region of the phase diagram.
Specific heat and related properties of some AIIBIVC and AIBIIIC semiconducting compounds between 2 and 300 K
Authors: Bischof J. , Bohmhammel K. , Deus P. 
Published: January 2007

AbstractFrom specific heat measurements of the ternary semiconducting compounds ZnSiP2, ZnSiAs2, CdGeAs2, CuGaSe2, and CuInTe2 Debye characteristic temperatures and standard entropy values are calculated within the temperature range from 2 to 300 K.
The role of argon in yttrium aluminates
Authors: Kvapil Ji. , Mánek B. , Perner B. , Kvapil Jos. , Becker R. , Ringel G. 
Published: January 2007

AbstractSpectral properties of YAG and YAP grown in vacuum or under ArH2 protective atmosphere were compared. The latter contained small amounts of argon which was detected by a laser mass spectral analysis. Ar impurity evokes brown colour of unannealed crystals and strenghtens anomalous red colour of annealed (Particularly in O2) YAP crystals doped with Nd + Cr or Nd + Mo. The same red coloration of the doped YAGs is less stable.
On the dispersion of the refractive index in AIIBVI thin films
Authors: Łepek M. 
Published: January 2007

AbstractWe propose a new calculation following traditional methods for deducing refractive index from the fringe pattern of the transmission spectrum of a thin transparent CdS, ZnS, and ZnxCd1−xS film surrounded by nonabsorbing media. The error in the refractive index measurements is 4–5%. We have found that polycrystalline CdS, ZnS, and ZnxCd1−xS evaporated films have refractive index different from those of single crystal material.
Metalorganic chemical vapour deposition of oriented ZnO films
Authors: Kaufmann Th. , Fuchs E. , Webert M. 
Published: January 2007

AbstractThin uniform films of ZnO could be obtained by MOCVD using Zn(CH3)2‐THF adduct and H2O as reactants. The film growth was carried out at atmospheric pressure. A vertical resistance‐heated cold‐wall reactor system was used. Highly c‐axis oriented ZnO films being very smooth and having a low resistivity were grown on (100)Si and (100)Si/SiO2 under certain conditions. Epitaxial growth could be achieved on (1102)‐sapphire. The dependence of the properties of the films on the growth conditions was investigated.
GaPAlxGa1−xP heterostructure edge coupling waveguides for hybrid integrated optic devices
Authors: Díaz P. , Gonzalez C. 
Published: January 2007

AbstractIn this paper we present the performance of GaPAlxGa1−xP heterostructure waveguides for integrated optic hybrid devices. The waveguide layer is graded with a parabolic refractive index profile for the light emission of a DHGaAs semiconductor laser. The waveguide heterostructure performed allows to couple at it edge crossection semiconductor laser or photodetector as well as fix or solder them on the same substrate on which the heterostructure layers were deposited.The heterostructure layers were grown by liquid phase epitaxy and the heterostructure waveguide was performed by means of etching technics specially developed for this purpose.Both, the growth procedure, as well as the etching technics are described. The results achieved are shown in curves and photographs, taken on a scanning microscope.
A study of ferroelectric domain patterns in orthorhobic KNbO3 with optical microscopy
Authors: Jun Chen , Wen‐shan Wang , Qi Li , Duan Feng 
Published: January 2007

AbstractFerroelectiric domain patterns in natural surface layers of Czochralski as‐grown crystals are very complicated. The inner domain patterns are comparatively simple and consist of a regular arrays of so‐called thin lens‐like 90° domains. Only few inner 60° and 120° domains crossing the 90° domain arrays are observed. The inversion or 180° domains are shape‐like separated islands. The 60° microdomains are easily introduced into the surface layers during the specimen processing. There are some elastic interactions between the different kinds of ferroelectric domain walls, the orientations of which are in good coincidence with the theory proposed by Janovec.
Nitrido‐phthalocyanine‐rhenium (V) structure and absorption spectra
Authors: Mrwa A. , Giegengack H. , Starke M. 
Published: January 2007

AbstractThe crystal structure of nitrido‐phthalocyanine‐rhenium (V) has been determined from X‐ray diffraction date. The crystal data are: C32H16N9Re (tetragonal), a = 1.775 nm, c = 1.386 nm, Z = 4, ϱ = 2.23 g cm−3. Optical and infrared absorption spectra have been measured on sublimated films and compared with the corresponding spectra of other metal phthalocyanines.
On the crystal structure type of 2 CsCl · CoCl2 · 2 H2O
Authors: Balarew Christo , Tepavitcharova Stefka 
Published: January 2007

AbstractThe following three‐component systems have been studied: CsClMnCl2H2O at 25 °C; 2 CsCl · CuCl2 · 2 H2O—2 CsCl · CoCl2H2O at 10 °C and 2 CsCl · MnCl2 · 2 H2O—2 CsCl · CoCl2H2O at 25 °C and 10 °C. It was established that Co2+‐ions do not substitute isodimorphously the Cu2+‐ions in the tetragonal salt 2 CsCl · CuCl2 · 2 H2O, whereas in the case of the triclinic salt 2 CsCl · MnCl2 · 2 H2O they can substitute isodimorphously the Mn2+‐ions.The theoretical considerations supported by the results obtained allow to predict the existence of the double salt 2 CsCl · CoCl2 · 2 H2O as well as the type of its crystal structure — triclinic, space group P1.
Combined surface analytical and electrochemical investigations of RuTiSn mixed oxide electrocatalysts
Authors: Wagner N. , Kühnemund L. 
Published: January 2007

AbstractUsing a galvanostatic oxygen exposure, it can be shown by XPS and SEM that admixtures of Sn (2 at.%) to RTO anodes inhibit the corrosion of both the bulk ruthenium species and the titanium substrate interface. The inhibitor effect is strongly dependent on the Sn segregation to the surface region blocking the channels of oxygen diffusion in incoherent active layers for Cl2 evolution.
An AES/XPS study of oxygen involved reactions on InSb
Authors: Wolf B. , Zehe A. 
Published: January 2007

AbstractThe oxidation of ion‐etched InSb(110)‐cleavage planes was investigated by means of AES and XPS, respectively. Whereas the sticking coefficient of oxygen at indium sites was found to reach a saturation value after slight ion bombardment, the oxygen uptake rate of antimony remains low (sticking probability in the 10−7 range) with raising ion dose to a point where a drastical change in oxidation behaviour occurs at ion doses in the 10−2 As · cm−2 range. Then indium and antimony are nearly simultaneously oxidized with sticking coefficients of roughly 10−3. Cluster formation is discussed as one possible mechanism to explain the experimental findings. Adsorption experiments on disordered surfaces can contribute to a better understanding of surface reactions during gas phase growth of single crystals, since the in‐growth situation of the top layer of the latter is far away from the ideal situation that is prepared by in situ cleaving only.
The influence of titania content on structure and properties of spherical mixed silica/titania particles
Authors: Bräuer K. , Hörhold H.‐H. , Klemm E. , Krah S. , Rudakoff G. , Vogelsberger W. 
Published: January 2007

AbstractSpherical mixed silica/titania particles are prepared from silica/titania sol by an ultrasonic vibrator. The titania content of the samples varies from pure silica to a titania mole fraction of 0.31. Narrow size distributions with most frequent particle diameter of about 1 μm are obtained. Specific surface area and pore volume, mean pore radius as well as the meso pore size distribution are influenced by titania content. The spheres are composed of both silica and titania homogeneous distributed as it is indicated by scanning electron microscopy. X‐ray diffraction studies show that the particles must be considered amorphous. Structural modifications of the framework are detected. Samples with varying refractive index may be prepared.
Phase relations and crystal growth of YBa2Cu3O7−δ in the system YO1.5BaOCuO
Authors: Fischer K. , Hergt R. , Linzen D. 
Published: January 2007

AbstractThe liquidus face of the system YBa2Cu3O7−δBaCuO2CuO was investigated by DTA. We found liquidus temperatures below 1000 °C only in a narrow region with small yttrium oxide content near the eutectic of the system BaCuO2CuO. The crystallization path of crystal growth experiments is discussed and the principle structure of the phase diagram is derived. Single crystals are grown being superconductive after thermal treatment in oxygen atmosphere.
Diffusive‐convective mass transport of HgI2 in closed ampoules
Authors: Laskowski Jarosław , Przyłuski Jan , Conder Kazimierz 
Published: January 2007

AbstractThe mass transport rate of HgI2 in closed ampoules with the addition of He, Ar or Xe at different pressures (20–200 Torr) was gravimetrically measured. Diffusive and convective mass fluxes in the systems studied were calculated according to vapour transport models. The influence of technological parameters, i.e. temperature, pressure, kind of added gas, and ampoule diameter, on the mass transport of HgI2 vapour was studied. Mechanisms of vapour flow in the applied experimental conditions are discussed.
Temperature dependence of the photoconductivity in CuInTe2 single crystals
Authors: Tomlinson R. D. , Neumann H. , Slifkin M. A. , Al‐Saffar I. S. , Al‐Rahmani A. 
Published: January 2007

AbstractThe temperature dependence of the steady‐state photoconductivity of as‐grown and annealed CuInTe2 single crystals was measured in the range from 77 to 300 K. A model with two electron trapping centres is proposed to explain the experimental data.
The crystal structure of zinc azide · 2‐methylpyridine at 98 K
Authors: Mautner Franz A. , Kratky Christoph 
Published: January 2007

AbstractThe crystal structure of the title compound has been determined by single crystal X‐ray diffraction methods at 98 K. Zinc azide · 2‐methyl pyridine crystallizes in the space group P1 with a = 6.028(2) Å, b = 7.610(3) Å, c = 10.052(4) Å, α = 92.81(3)°, β = 101.08(2)·, γ = 94.64(3)° and Z = 2. Least‐squares refinement gave an R value of Rw = 0.039 for 2096 observed reflections.Each zinc atom is surrounded by four nitrogen atoms of different azide groups and one nitrogen atom of the pyridine adduct in a distorted trigonal bipyramidal fashion. The ZnN5‐polyhedra share common edges to form chains along the crystallographic a‐axis.
On the investigation of dopant boundaries in silicon device structures by means of SEM‐EBIC
Authors: Hoppe W. , Kittler M. 
Published: January 2007

AbstractThe capabilities to study the geometrical construction of silicon devices by the technique of the electron beam induced current (EBIC) are reviewed with particular emphasis to the 2‐dimensional determination of dopant boundaries (p‐n junctions) including a discussion of demands for such investigations from a microelectronic point of view. The investigations of buried layers and MOS short‐channel transistors are outlined. As a substantial topic the preparation of electrically stable surfaces at cleaved samples is discussed and an example of the possibility of cross‐sectional analysis for junction delination is briefly given.
Structural characteristics of some lanthanide violurate complexes
Authors: Awadallah R. M. , Farag I. S. Ahmed , Gad A. A. M. 
Published: January 2007

AbstractThe magnetic moments and the electronic spectra of violurate complexes of Ce3+, Pr3+, Pr4+, Nd3+, Sm3+, Eu3+, Gd3+, Ho3+, Er3+, and Yb3+ have been investigated. The solid complexes are paramagnetic and have magnetic moment values near to the ground state values of the free ions. Few cases differ, since there exist possible electronic transitions (4f → 5d) in case of Ce3+ complexes and (f → f) for Ho3+ and Dy3+ complexes. The magnetic measurements in connection with the electronic spectra were used to decide the different electronic structural configuration of elements and hence the configuration of the coordination polyhedra around the central metal ions of the investigated complexes.
On the initial stage of plastic deformation of sulphur‐doped gallium phosphide
Authors: Boehnke O. , Paufler P. 
Published: January 2007

AbstractThe overall deformation behaviour between room temperature and 1000 K has been investigated by bending and uniaxial compression at small strains ≦ 0.1%. Ductile‐to‐brittle transition temperature was found at 44% of the melting point. Dislocations are generated mainly at surface irregularities. Whereas screw dislocations predominate at the beginning 30° and 60° segments become more important after cross slip and interaction of different slip systems.
Comprehensive characterization of CdTe and (Cd, Zn)Te single crystals by a chemical etchant
Authors: Wermke B. , Mühlberg M. , Engel A. , Rudolph P. 
Published: January 2007

AbstractUsing a known chemical etchant low‐ and high angle boundaries and lamellar twins can be seen on CdTe and (Cd, Zn)Te crystal ingots as a whole as well as on slices with naked eyes. Also the polarity of {111} samples can be determined in this way. Etch pits are produced on cut and polished surfaces independent of their crystallographic orientation. A new modified etchant was used to study the low angle subgrain structure on (111)Te surfaces.
Numerical analysis of various heat input regimes applied to liquid encapsulated Czochralski crystal growth
Authors: Böttcher K. , Krüger A. , Schleusener B. 
Published: January 2007

AbstractBy the hand of a stationary system‐oriented model of the InP crystal growth (LEC) various regimes of heat input into the melt are demonstrated. They are compared by regarding their influence over the maximal temperature of the melt, the curvature of the crystallization front, and the temperature of the crystal at the end of the boric oxide.
Crystallization kinetics and phase transformations of zinc‐ and cadmium diphosphide films
Authors: Denis V. A. , Sheleg A. U. , Unyarkha L. S. 
Published: January 2007

AbstractThe kinetics of isothermal crystallization of amorphous ZnP2 films in the temperature range from 730 to 810 K and amorphous CdP2 films between 630–770 K has been investigated. The kinetic curves of isothermal transformation of amorphous films into crystalline ones have been obtained. For ZnP2 the transformation occurs as follows: amorphous films → α‐ZnP2 (tetragonal modification) → β‐ZnP2 (monoclinic modification). For CdP2 – amorphous films → γ‐CdP2 (cubic modification) → β‐CdP2 (tetragonal modification). From the experimentally determined kinetic curves the stability diagrams for ZnP2 and CdP2 films have been plotted. The most stable modification in the investigated temperature range are β‐ZnP2 and β‐CdP2 other ones are metastable. The values of effective energy of activation of transformation have been determined.
Time‐dependent trench profile formation during RIE‐processing of silicon with CCl2F2‐gas mixture
Authors: Kühne H. , Glück B. 
Published: January 2007

AbstractThe formation of the three main types of trench profiles (step‐like profile and trapez‐like profile the small side down or up, respectively) and their time‐dependent development during trench etching have been explained by taking into consideration not only the vertical etch rate and the factor of etching anisotropy given by mask undercutting but also the additional factor of etching anisotropy given by applying the definition to the bottom rim of the trench. Concidering both time‐and depth‐dependence of etching anisotropy the formation of projecting brims within a trench can be interpreted, too.
Bulk flow phenomenon in Czochralski configuration caused by low frequency vibrations
Authors: Zharikov E. V. , Prihod'Ko L. V. , Storozhev N. R. 
Published: January 2007

AbstractThe described experimental results demonstrate that vibrations can essentially affect the melt flow in growth processes. The existence of vibrational convection must be taken into account in interpreting the results of using the vibrations in crystal growth processes (IZERGIN et al.; LANGANECKER, FRANDSEN; NIKITINA et al.; WITT, GATOS). Vibrational convection opens new advantages to control the convective movement of melt and of interface shape during the crystal growth.
Trends in the microhardness of the CuBIIIC chalcopyrite compounds
Authors: Neumann H. 
Published: January 2007

AbstractOn the basis of a microhardness scaling law found for the AIIBIVC compounds and of the dependence of the microhardness on conductivity type and composition observed experimentally in CuInSe2 a model is proposed to describe the trends in the microhardness of the CuBIIIC compounds. The results are compared with experimental data and other microhardness estimates. It is found that most of the existing microhardness measurements can be interpreted within the model.
Intermolecular free lengths and odd‐even effect studies in certain alkoxy benzylidene butylanilines
Authors: Venkatacharyulu P. , Prasad K. S. R. , Rao J. V. 
Published: January 2007

AbstractUsing the thermoacoustic data the mean free lengths (Lf) as a function of temperature are estimated for certain members of the homologous series of alkoxy benzylidene butylanilines with m = 2 to 7 except 3, in their isotropic, mesophases as well as at and in the immediate vicinity of the phase transition temperatures. From these studies it is observed that the mean free lengths also exhibit odd‐even effect.
Hydrothermal analcime synthesis at 10 MPa isobar
Authors: Pechar František 
Published: January 2007

AbstractHydrothermal analcime synthesis at 10 MPa isobar and 100, 200, and 300 °C isotherms was performed. As synthesis initial components the minerals nepheline, albite, natrolite, jadeite, wairakite and the mixtures nepheline + albite and nepheline + natrolite were used. 1 M Na2SiO3, 1 M NaCl and 0.1 M NaOH (pH = 14, 7, 13) solutions were applied as the hydrothermal medium. On evaluating the synthesis products by means of X‐ray diffraction analysis and X‐ray microanalysis (EDAX) it was estimated that different analcime structural modifications originate especially at temperatures above 200 °C in neutral and alkaline medium from all the mentioned minerals. Analcime with a higher symmetry of the unit cell of crystals form at temperatures above 250 °C particularly.
Rheological behaviour of lamellar eutectic AlAl2Cu elaborated by induction heating
Authors: Bornier L. , Birocheau J. 
Published: January 2007

AbstractThis paper presents solutions to the experimental problems encountered in the elaboration of lamellar AlAl2Cu or fibrous AlAl3Ni eutectic samples using the Bridgman technique. The objective is to prepare samples for use in mechanical tests.The investigation of the elaborated structures of AlAl2Cu (orientation, grain selection, shape of the solid‐liquid (S.L.) interface, interlamellar spacing λ…) can then be used to confirm the predicted behavior.Creep tests under constant applied stress σ (from 2 to 5 · 107 N/m2) at temperatures from 300 to 450 °C show:

– that a stationary state exists (with constant strain rate

)
– the influence of an imperfect orientation
– the existence of a Bailey‐Norton creep law

= kσn. This law leads to the possiblity of finding a constitutive equation for high temperatures tests.
X‐ray two‐crystal diffractometer for testing of plane analyser crystals
Authors: Dressler L. , Wehrhan O. , Uhlig I. , Gütt R. 
Published: January 2007

AbstractA two‐crystal diffractometer (TCD) for testing the mosaic structure of LiF crystals is presented. Peculiarities are the adapted sensivity (angular minutes), short measuring times, large registered areas and the possibility of application for various kinds of surface treatment.
Nonstoichiometry in steps on AB crystals (II). Extended treatments
Authors: Arnold H. , Fuchs G. , Kaufmann T. , Webert M. 
Published: January 2007

AbstractConcentrations of atoms with different numbers of nearest neighbours, and of the kink and non‐kink positions between atoms in step fronts, have been calculated by two treatments. The results differ in the general case, but agree in cases with extreme nonstoichiometry as well as in nearly stoichiometric cases. With respect to the relevance of the model calculations, further investigations are necessary on step reconstructions, on the positions of stability limits of AB compounds in terms of step nonstoichiometry, and on the possibility of roughening transitions in connection with step nonstoichiometry.With increasing nonstoichiometry in the steps, neighbouring kink positions, and the corresponding neighbour‐kink atoms become increasingly important. In contrast to this, the concentrations of double kink positions become smaller, and they vanish in the extreme cases where the PBC‐directed steps consist merely of A, or of B neighbour‐kink atoms. These concentrations are negligible in the extended model calculations at sufficiently low temperatures, together with concentrations of triple and further multiple kink positions.
Growth of Na2EuCl4 particles studied by means of their effect upon the yield strength of NaCl:Eu2+ crystals
Authors: Nowak‐Woźny Dorota 
Published: January 2007

AbstractThe hardening of NaCl crystals induced by the presence of europium ions has been systematically investigated in two regions of temperatures (below 343 K and above 473 K) as function of the aggregation and/or precipitation stage of the dopant. The kinetics of Eu2+ — clustering was followed by taking the δσ0(tan) — data at various annealing temperatures Tan. The results have been discussed in frames of the available theoretical models and compared with those obtained previously from OA‐ and ITC‐data.
Structural changes of some Fe‐containing layer silicates in the presence of as and S under hydrothermal conditions
Authors: Frank‐Kamenetskii V. A. , Kotov N. V. , Ernst R. , Goilo E. A. 
Published: January 2007

AbstractStructural changes of chlorite, berthierine, biotite were investigated under hydrothermal conditions at pH2O = 100 MPa (1 kbar), T = 200–600 °C, run over 3 days with additions of AsS, NaCl, dolomite. The synthesis of pyrrhotine and arsenopyrite was detected at the expense of extraction of Fe from the structures of transforming layer silicates. The degree of the removal of Fe with the formation of sulphides depends on its being blocked up by a silicate surrounding. It grows in the sequence biotite‐chlorite‐berthierine.
Contribution to the Si doping of bridgeman GaAs
Authors: Siegel W. , Boudriot H. , Koi H. , Deus K. , Oettel O. , Schneider H. A. 
Published: January 2007

AbstractGaAs: Si with different doping level was grown by the gradient freeze method. The crystals were characterized by structural, electrical and optical methods concerning especially the dependence of the epd and the compensation degree on the carrier concentration.