bluuebunny/crossref_metadata_2025_split huggingface dataset:
Locally Detailed Electroluminescence for Thin Optical Fiber Coupling to LEDs
Authors: Hesse L. , Zehe A. , Navarro H. 
Published: January 2007

AbstractLocally detailed electroluminescence properties of a single heterojunction (SH) light emitting diode (LED) are reported. The knowledge and consideration of such properties is of major interest when thin optical fibers are to be attached to a side face of a Fabry‐Perot structure. The virgin electroluminescence spectrum inside the active region was calculated and is taken as reference for the local emission spectrum at near‐field points at a side face. Considerable peak shifts, up to 120 meV. and intensity reductions occur for the transmitted spectrum, when proceeding from the n‐side of the junction to the p‐side.
Autodoping during the deposition of epitaxial Silicon layers from the gas phase (I). Autodoping from the gas phase
Authors: Kühne H. 
Published: January 2007

AbstractThe doping profile within the autodoping range of epitaxial layers deposited on lowresistance substrates, is considered the result of redistributing a substrate doping fraction through the substrate layer boundary, of incorporating a limited amount of dopants from the gas phase, originating from the preepitaxial process, and the result of incorporating dopants, externally admitted to the gas flow during the deposition. Assuming a special incorporation equilibrium to exist for the gas phase fraction of autodoping an analytic expression is derived, correlating the autodoping profile characteristic to the limited amount of dopants in the gas phase. The extent is discussed, to which the gas phase fraction of autodoping may be influenced by varying the deposition process.
Strength and microstructures of Benzoic Acid‐Benzamide system
Authors: Sharma B. L. , Sharma N. K. , Bassi P. S. 
Published: January 2007

AbstractPure end products in their binary eutectic of a benzoic acid‐benzamide system, grownunidirectionally and randomly, exhibited marked anisotropy in their peculiar properties particularly if the growth is carried out in some periodic manner. Modulus of ruptures of eutectic composite and the constituent materials for both the growths have been determined. Directional‐growth of the composite yields a bending strength quite larger than that can be obtained from an anomalous growth. Pure components also offer slighly greater strength in an ordered growth. Microphotographs of grown materials are related to the mode of crystallization of the materials.
Application of holographic interferometry to the study of properties of Bi2Se3 crystals
Authors: Kaplanová M. , Synek J. , Horák J. 
Published: January 2007

AbstractA holographic interferometry method for visualisation of structure non‐homogeneities in large Bi2Se3 monocrystals with Cd and In admixtures is presented. The natural cleavage (0001) faces of Bi2Se3 monocrystals were used for preparation of samples for surface quality investigation. The interference patterns obtained with double‐exposure method show the deformation field distribution caused by a suitable formed temperature gradient. The interferogram obtained by the described method make it possible to select a perfectly homogenous part of prepared monocrystalline sample which is inevitable for measurements of optical and electric conductivity properties.
An X‐ray diffraction refinement of the structure of natural thomsonite
Authors: Pechar FrantiŠek 
Published: January 2007

AbstractThomsonite Na2Ca4Al10Si10O40, orthorhombic Pncn, a = 1.3124 nm, b = 1.3078 nm, c = 0.662 nm, V = 1.1369 nm3, Z = 2, Dm = 2.30, Dc = 2.26, μ = 12.4 cm−1. The average length of the bond T–O = 0.1685 nm. The final R‐value for 456 independent observed reflections is 0.085.
X‐Ray topographic study of the influence of thermal annealing on the bending of 49BF2+‐implanted Si wafers
Authors: Vassilev I. S. , Furmanik Z. , Petrov I. N. , Botev P. A. , Auleytner J. 
Published: January 2007

AbstractThe influence of thermal annealing on the image contrast of the boundaries of 49BF2+‐implanted regions in Si is investigated by means of X‐ray topography. The contrast is used for studying the wafer bending and the stress types. It is shown that the final state of deformation is determined by: (1) the expansion of the surface layer caused by the implantation, (2) the contraction of this layer caused by the annealing. Effect (1) or (2) dominates depending on the implantation dose and annealing conditions. The possibility of compensating both effects leading to complete elimination of the bending of the implanted wafers is established. The results are discussed on the basis of the correlation between the deformation state of the wafers and the percentage B atoms occupying substitutionally Si‐lattice sites.
Investigation of the Crystallization Process in the Verneuil Techniques
Authors: Borodin V. A. , Brener E. A. , Tatarchenko V. A. 
Published: January 2007

AbstractThe stability of the process of crystallization in the Verneuil techniques is analyzed, taking into account the geometrical shape of the molten layer surface and specific features of the heat and mass transfer typical for this method of crystal growth. The process is stable for crystal radii below the capillarity constant.
Growth of Potassium Sulphate Crystals by Silica Gel Technique
Authors: Garcia‐Ruiz J. M. , Martin‐Vivaldi Caballero J. L. 
Published: January 2007

AbstractSingle and transparent crystals of potassium sulphate up to 30 × 3 × 3 mm in size have been grown by silica gel technique, using various methods (two‐layers three‐layers and hybrid gel technique) which are described. The effects of the three differents alcohols (used as top solutions) upon the quality and nucleation of crystals are also reported. The “growth and equilibrium” morphologies and microstructures of the habit faces are discussed.
Melting Diagrams of the Quaternary Systems Ga–In–As–Ge and Ga–In–As–Sn
Authors: Müller K. , Apelt R. , Jacobs B. , Butter E. 
Published: January 2007

AbstractEquilibria between quaternary liquid phases Ga–In–As–Ge(–Sn) and the ternary solid phase Ga–In–As have been calculated by application of the KRUPKOWSKI formalism on the excess free enthalpy. Experimental liquidus data were obtained from solubility experiments in a LPE equipment. Results of calculation and experimental liquidus data are compared.
The Influence of Mineral Impurities on the „Sulphur Puffing”︁ at High Temperature Treatment of Brown Coal Pitch Cokes
Authors: Preiss H. , Born D. , Winkler E. , Olschinka P. 
Published: January 2007

AbstractCokes rich in sulphur usually show throughout the high temperature treatment between 1500 and 1800 °C an irreversible dilatation which can be suppressed by additives of inorganic oxides or salts. In brown coal pitch cokes with high content of sulphur and mineral impurities (ash), however, this suphur puffing cannot be observed. Basic ash components (e. g. CaO, Fe2O3, MgO) are responsible for the puffing inhibition. The inhibition is already sufficient if the concerntration of basic ash components equals the suphur conentration.
Spiral growth of potassium bichromate crystals
Authors: Szurgot M. , Sangwal K. 
Published: January 2007

AbstractSome observations of growth spirals and hillocks on {001} surfaces of potassium bichromate crystals grown from aqueous solutions are presented and discussed. It is shown that a spiral pattern in fact represents a macrospiral developed as a result of the cooperative action of a group of dislocations.
Energetic analysis of partition coefficients for melt crystallization in LnF3–Ln'F3 Systems)
Authors: Urusov V. S. , Grigorash Yu. P. , Karelin V. V. , Sobolev B. P. 
Published: January 2007

AbstractEnergetic theory of isomorphous miscibility is used for interpretation of LnF3–Ln'F3 phase diagram types and values of coefficients of Ln' distribution between crystals and melt. Such an analysis supplies the information for estimates of unknown properties of solid solutions of hexagonal tysonite or orthorhombic yttrium fluoride types and binary melts. Besides that there is a possibility of prediction of phase equilibria in many of those LnF3–Ln'F3 system of 105 possible ones which are not yet studied experimentally.
Impurity distribution in natural diamond crystals
Authors: Aleksandrov L. N. , Gafitullina D. S. , Khaidarov A. A. 
Published: January 2007

AbstractAn activation analysis and neutron autoradiography have been applied to study the impurity distribution in natural diamond crystals. The impurity incorporation pattern has been studied on 〈100〉 and 〈110〉 lamellal cut from crystals of an octahedral, rhombododecahedral, and cubic habit having a zonal texture. Cobalt impurities, unlike other elements, concentrated in the centre of the middle regions of diamonds irrespective of the crystal growth shape. A heterogeneous mechanism has been suggested for natural diamond genesis.
Logarithmic Anomaly in the Debye‐Waller Factor and Thermal Expansion Coefficient at Ferroelectric Phase Transition in KDP
Authors: Zvirgzds J. A. , Zvirgzde J. V. 
Published: January 2007

AbstractTemperature dependence of the thermal expansion coefficient and the Debye‐Waller factor along the polar axes in KDP were investigated by means of X‐ray diffraction. A logarithmic anomaly was observed in the range from Tc up to 6 K above Tc.
On Unstable Directions of Dislocations in the Intermetallic Compound V3Si
Authors: Paufler P. , Boehnke O. 
Published: January 2007

AbstractThe angular dependence of the reciprocal elastic energy of a straight dislocation in the superconductor V3Si has been computed for different temperatures and slip systems taking elastic anisotropy into account. Regions of instability have been found which depend on temperature. Crystallographic slip planes may be unstable against climb.
Structures of Azomethine Imines of the Pyrazolidone‐(3)‐type, (IV) The Structure of 1‐(4‐Methoxybenzylidene)‐pyrazolidone‐(3)‐betaine
Authors: Kulpe S. , Seidel I. , Geissler G. 
Published: January 2007

AbstractC11H12N2O2, Pcam, a = 14.512(6) Å, b = 10.516(2) Å, c = 6.812(3) Å, Z = 4, U = 1039.4 Å3, Dx = 1.30 g cm−3, μ(MoKα) = 0.999 cm−1, F(000) = 864.0, crystal size 0.5 × 0.3 × 0.25 mm, λMoKα = 0.71069 Å, crystals colourless. Final R = 0.039 for 831 independent reflections excluded those with |F0| < 10 σ(F0).The intensities were measured with an automatic diffractometer. The electron structure of the molecule can be explained by assuming that the molecule consists of the azomethine imine unit with polymethinic character and the methoxybenzylidene unit with aromatic character, both units are linked via the C(4)–C(5) bond (1.440 Å). The whole molecule is exactly plane. All non‐hydrogen atoms lie exactly on the mirrorplanes perpendicular to the z‐axis with the plane distance 3.406 Å. Instead of the general Z = 8 there is the special Z, 4. There exist intermolecular C–H … 0 hydrogen bridges in the planes of the molecules.
Studies on Nickel Oxide Mixed Catalysts (X) Thermoanalytical Investigations on NiO/SiO2 Catalysts and Nickel Layer‐silicates
Authors: Wendt G. , Siegel H. , Schmitz W. 
Published: January 2007

AbstractThe processes occurring at the thermal decomposition of NiO/SiO2 catalysts prepared by precipitation deposition of nickel talc and nickel antigorite were investigated by means of DTA/TG method, high temperature X‐ray diffraction and infrared spectroscopy. In the case of NiO/SiO2 samples X‐ray amorphous nickel layer‐silicates (mixtures of nickel antigorite/nickel talc) were formed in the process of preparation. Nickel hydroxide was observed at NiO contents > 40 mol%. Nickel talc and nickel antigorite decompose at increasing temperatures successively to the following phases: nickel talc, nickel antigorite → X‐ray amorphous phase → nickel oxide, nickel olivine, cristobalite.The dehydroxylation temperatures of the X‐ray amorphous nickel layer‐silicates are markedly lower than those of nickel talc and nickel antigorite.Es wurde die thermische Umwandlung durch Fällen hergestellter NiO/SiO2‐Katalysatoren, von Nickeltalk und von Nickelantigorit durch die Anwendung von DTA/TG‐Methoden, der Hochtemperatur‐Röntgendiffraktometrie und der Infrarotspektroskopie untersucht. Bei den NiO/SiO2‐Proben wurden im Verlaufe des Fällungsprozesses röntgenamorphe Nickelschichtsilikate (Nickeltalk/Nickelantigorit‐Gemische) gebildet. Nickelhydroxid wurde bei NiO‐Gehalten > 40 mol‐% beobachtet. Nickeltalk und Nickelantogorit zerfallen bei Temperaturerhöhung folgendermaßen: Nickeltalk, Nickelantigorit → → röntgenamorphe Phase → Nickeloxid, Nickelolivin, Cristobalit. Die Dehydroxylierungstemperaturen der röntgenamorphen Nickelschichtsilikate sind beträchtlich niedriger als die von Nickeltalk und Nickelantigorit.
A Multipurpose Graphite Boat for LPE Growth of Multilayer Heterostructures
Authors: Bolkhovityanov Yu. B. , Bolkhovityanova R. I. , Hairi E. H. , Chikichev S. I. , Yudaev V. I. 
Published: January 2007

AbstractIn the paper the results of the authors' work are summarized on the preparation of multilayer A3B5 heterostructures with the use of originally designed graphite boat. The main scheme of the boat design is described in detail and it is shown that the growth apparatus combine the favourable features of the known LPE growth techniques: epitaxy from thin solution layer, sliding boat technique and the technique based upon the displacement of one melt by another.
Effect of an External Electric Field on Polytypic Growth of CdI2 Crystals from Solutions
Authors: Pałosz B. , Przedmojski J. 
Published: January 2007

AbstractThe effect of an external steady electric field on polytypic growth of CdI2 crystals was investigated. Crystals were grown at four temperatures: 5, 25, 35, and 50°C with the use of four solvents: H2O, C2H5OH, 3 H2O + 1 C2H5OH and 1 H2O + 1 C2H5OH. The electric field of the intensity 500 to 2500 V/cm was oriented in two directions: perpendicular or parallel to the c‐axis of hexagonal plates of CdI2 crystals. The analysis of the effect of the field on polytypism of CdI2 was based on the analysis of the structure of about 800 crystals grown in the presence of electric field and of about 1000 crystals grown in neutral conditions. It was established that the weak electric field used for crystallization of CdI2 does not influence noticeably the relative stability of basic polytypes (2H, 4H) and of complex polytypic structures (ordered and disordered). The electric field may influence the structure of CdI2 crystals in two ways: (i) the polytypes formed in the presence of the field have on average two times larger cells than the polytypes formed in neutral conditions, (ii) the polytypes formed in neutral conditions have usually hexagonal cells; only 6 to 30% of polytypes are of rhombohedral type. When the electric field was used the percentage of rhombohedral polytypes increased to about 65%.
Effect of Different Parameters on the Liesegang Ring Formation of Lead Carbonate Crystals
Authors: Mohanan Pillai K. , Vaidyan V. K. , Ittyachan M. A. 
Published: January 2007

AbstractInfluence of different parameters like concentration of the outer electrolyte, age of the gel and impurities added to the outer electrolyte on the periodic precipitation of lead carbonate crystals in silica gel are presented. Increase of outer electrolyte concentration has the effect of increasing x2/t value while it decreases with increase of the gel age. Impurities added to the outer electrolyte delay the time of formation of the rings. All these observed results are explained.
Reciprocal Morphological Lattices and Growth Forms of Crystals
Authors: Follner H. 
Published: January 2007

AbstractCrystals are based on a morphological lattice, which – as a rule – possesses a higher symmetry than the structureal one. The morphological lattice is a Fourier transform of crystal morphology. The polyhedron resulting from the planes which perpendicularly bisect the lines between all symmetrically equivalent morphological points is referred to as reciprocal crystal. Through a Fourier transform of the reciprocal crystal the crystal space is recovered. In case of simple morphological lattices – the determination of central distances from the reciprocal morphological translation groups is possible here – the crystals can be shown in a Wulff‐plot. The procedure is to be discussed on different examples.
Microhardness and Resistivity Anisotropy of ZnO Plastic Deformation
Authors: Regel V. R. , Sizova N. L. , Chernysheva M. A. , Dohnovskaya S. I. , Kuzmina I. P. , Lazarevskaya O. A. , Nikitenko V. A. 
Published: January 2007

AbstractIn the work is shown that hydrothermally grown ZnO crystals are characterized by the mosaic structure of ‘columnar’ type. The experimental and theoretical data about geometry of the slip systems in ZnO crystals are obtained and also anisotropy of the microhardness is measured.
X‐ray Studies on the Liquid Crystalline Phases of the 4‐[4‐n‐Heptyloxy‐Benzylidene‐Amino]4'‐cyanobiphenyl
Authors: Diele S. , Jaeckel D. , Demus D. , Sackmann H. 
Published: January 2007

AbstractBy means of X‐ray diffraction studies of oriented and non‐oriented samples the lattice parameters of the orthorhombic cell of the SE phase as well as of the hexagonal cell of the SB phase were determined. By packing considerations a bimolecular building unit with oppositely arranged cyano‐groups was assumed in the case of the SE phase.The SB phase is characterized by an ABAB sequence of the smectic layers in which the molecules are hexagonal arranged. The increasing mobility of the molecules at increasing temperature offers the possibility for a part of the molecules to slide in a more stable dimerized form. In the NR and SA phase the existence of monomers as well as of dimers is assumed.In this way a conception of the phase transitions SE → SB → NR → SA is given on the base of a decrease by steps of the dipole‐dipole repulsion.
OD interpretation of the crystal structure of lithium tellurite, Li2TeO3
Authors: Kuban R.‐J. 
Published: January 2007

AbstractThe OD groupoid family of the structure of lithium tellurite, Li2TeO3, is characterized by the symbol: magnified image.The OD groupoid 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. Any OD layer is idendical to a Li2TeO3 double sheet. The assumption of Folger that the structure is an OD structure has been found to be justified.
Growing of local smectic C monocrystals from an initially twisted nematic phase
Authors: Petrov M. , Komitov L. 
Published: January 2007

AbstractThe growing of smectic C single local monocrystals was investigated from an initially twisted nematic phase with smectic C ordering (p‐n‐alkoxybenzoic acid). Characteristic longitudinal and transverse dislocation lines have been observed at growth in a thin liquid crystal cell, single local monocrystals are discussed. The evolution was studied of the smectic C phase from cybotactic groups in a nematic phase toward needlike nuclei near to the nematic‐smectic C phase transition and after that after that toward the local single monocrystals.
Peculiarities of the melt growth of metal single crystals with specified crystal‐geometric and structural parameters
Authors: Kazarov Yu. G. , Lavrentev F. F. 
Published: January 2007

AbstractThis paper describes the authors' modifications of Kapitza and Bridgman apparatus and growth methods of metal single crystals with specified crystal geometric and structural parameters. The effects associated with defect formation are discussed. The features of the effects in their relation to the crystal lattice types and crystallographic orientation are indicated. It is concluded that one of the main factors responsible for the defect formation during single crystal growth in the mould is strain. This is due to thermomechanical stresses arising during the crystal growth and cooling to room temperature, from the difference in thermal expansion coefficients of the crystal and mould materials.
Mechanism of melilite formation during a sintering process
Authors: Böhme O. , Paufler P. , Schreiter P. 
Published: January 2007

AbstractSolid solutions of melilite were produced by industrial raw materials (phosphorous furnace slag, dolomitic limestone and clay) at temperatures till 1200 K. At this solid state reaction different processes are participating. From the formation rate at constant temperature different processes were recognized by graphical analysis and explained by a mechanism of melilite formation. Some different temperatures were used. The investigations are used to produce a new ceramic material on the base of melilite.
On the delay of thermally activated motion of pyramidal dislocations in zinc
Authors: Gektina I. V. 
Published: January 2007

AbstractThe effect of shear stress and temperature on the delay time, ti, of thermally activated motion of dislocations in the {1122} 〈1123〉 slip system in Zn single crystals is studied. The delay is associated with a higher density of crystal defects at the initial path of dislocation motion.
Special features of optical strength change in melt‐grown NaCl crystals
Authors: Erofeev V. N. , Gorbunov A. V. , Val'Kovskii S. N. 
Published: January 2007

AbstractThe variation of the CO2‐laser pulse induced breakdown threshold has been studied experimentally in melt‐grown NaCl crystals. An increase of the optical strength (up to two order of magnitude) is observed from the „top”︁ towards „bottom”︁ of the large diameter crystal boules, i.e. in the direction in which the impurities are driven away. The dependence of the threshold with the Ca2+ concentration demonstrates a complicated character of the effect of the impurity content on the optical strength of sodium chloride.
Luminescence studies on zeolite crystals
Authors: Joshi M. S. , Bhoskar B. T. 
Published: January 2007

AbstractObservations and results on studies of photoluminescence in zeolites are reported. Excitation and emission spectra for natrolite, scolecite and thomsonite are illustrated. Peak positions in spectra are summarised in tabular forms. It is shown that principal emission band in natrolite and heulandite increases with increase in iron percentage in them. Absence of this situation in stilbite is explained in terms of Na+ or K+ centre killers. It is established that photoluminescence observed in the present case is due to de‐alumination of zeolites under study.
Analysis of Pb dopant distributions in KCl monocrystals by energy dispersive X‐ray spectrometry
Authors: Krajewski Th. , Malicskó L. 
Published: January 2007

AbstractThe energy dispersive X‐ray microanalysis in combination with the scanning electron microscopy was used for investigations of the microdistribution of Pb dopants in solution‐grown KCl crystals. In applying an absorption filter technique (using an about 30 μm thick aluminium foil arranged into the X‐ray path between the specimen and the detector) the resulting detectability of the Pb minor constituents is improved by a factor of about 3. The minimum detectable content of lead within the KCl matrix could be estimated to have the order of magnitude of 0.1 mole per cent Pb.
Thermodynamic analysis of solute‐solvent interactions in the solubility‐temperature relations of alkaline‐earth metal tungstates and sodium tungstate
Authors: Roy B. N. 
Published: January 2007

AbstractThis paper presents a study of thermodynamic analysis of the solubility‐temperature phase diagrams for solutions of calcium, strontium and barium tungstate in sodium tungstate melts in the temperature range 660 to 1200 °C. At temperatures 1000 °C and above, the solutions were ideal but below 1000 °C the solutions became non‐ideal and the non‐ideality increased with decreasing temperature. At any mole fraction concentration of the solute the excess free energies of mixing and the activity coefficients increased in the order CaWO4 > SrWO4 > BaWO4, whereas the excess chemical potentials decreased in the order CaWO4 < SrWO4 < BaWO4.