bluuebunny/crossref_metadata_2025_split huggingface dataset:
A correlation between concentration of deep levels and growth conditions for VPEGaP
Authors: Seifert W. , Jacobs K. , Pickenhain R. , Biehne G. 
Published: January 2007

AbstractA minimum in deep level concentration in VPE‐GaP is found which corresponds to exceptional growth conditions near a relative maximum of the growth rate r in dependence on the GaCl input pressure pG̊aCL. The minimum occurs at the cross‐over between mass flow controlled growth (at low pG̊aCL.) and surface reaction controlled growth (at high pG̊aCL.).
The precipitation of sparingly‐soluble alkaline‐earth metal phosphates in gelatine gels by diffusion of anion (i). the precipitation of calcium hydrogen phosphate dihydrate and basic calcium phosphates
Authors: Packter A. , Chatterjee A. 
Published: January 2007

AbstractThe precipitation of different calcium phosphates in gelatine gels was studied by diffusion of disodium hydrogen phosphate solutions into ten percent gels containing calcium cation at liquid gel pHs from 6 to 11. At pHs 6.0 to 7.5, calcium hydrogen phosphate dihydrate (CaHPO4 · 2 H2O) was deposited as a continuous precipitate and then as rings of precipitate (the Liesegang phenomenon): their spacing coefficients varied with the reciprocal initial anion concentrations according to the Packter‐Matalon relation.At liquid gel pHs 8.0, 8.5, tretacalcium phosphate (Ca4H(PO4)3) was deposited as a continuous precipitate.At liquid gel pHs from 8.5 to 11, hydroxyapatite (Ca10(PO4)6(OH)2, Ca/P ratios = 1.50 to 1.67) was deposited as a continuous precipitate.The mechanisms of precipitation of the different calcium phosphates (in gelatine gels) is briefly discussed.
On the bindings in the crystal phases of Mn
Authors: Schubert K. 
Published: January 2007

AbstractThe heterotypism of Mn may be interpreted energetically when a temperature dependent valence electron concentration is supposed which takes on values between 2.2 and 0.6 electrons per atom. The room temperature phase Mn.r (= αMn) belongs to a series of structural types: Cr3Si, U.h1 (= βU), Mn.r, which occur in alloy systems such as MoReM (M = undetermined mole number) at certain values of the averaged group number (AGN) of the perodic system of chemical elements (rule of Raub). An interpretation of the series by means of the plural‐correlations model becomes possible when instead of the (Ekmanian) AGN count another (non‐Ekmanian) electron count is used. The phase Mo3Re (Cr3Si‐type) yields a simple bonding type (binding) which undergoes moderate transformations to form the phases Mo2Re3(U.h1) and MoRe3(Mn.r) and the binding of MoRe3 may be taken to be valid also for Mn.r; it corresponds to the valence electron concentration N′Ab = 2.16. For the high temperature phases Mn.h1 (= βMn) and Mn.h2 (= γMn) the values N′Ab = 1.6 and 1.0 are probable and allow the brass‐like structures Mn.h1 (C20) and Cu(Fl). The binding of Mn.h2, incidentally, explains the occurrence of the tetragonal metastable phase Mn.m. finally Mn.h3 (= δMn) crystallizing in the W‐type is isodesmic to Fe.h2 (= δFe), i.e. of the same binding.
Study of the oriented overgrowth of sodium nitrate crystals
Authors: Anuradha P. , Bhagavan Raju I. V. K. 
Published: January 2007

AbstractFormation of overgrowths of NaNO3 on crystalline and noncrystalline substrates has been investigated employing the solvent evaporation method. Calcite, Gypsum, Sodium chloride, Mica, Glass and Polystyrene films formed on glass have been employed as substrate materials. The solvents employed are water, liquid ammonia, methyl alcohol and n‐butyl alcohol. Random orientation of the overgrowths is observed on the substrates except in the case of calcite and mica. It is found that the morphology of the overgrowths manifests in the form of rhombic‐, triangular‐ and hexagonal platelets. The occurrence of (001), (110) and (111) twins is observed. The effect of supersaturation and nature of the substrate on the formation of overgrowths is considered.
Computation of the axial temperature distribution for the travelling heater method
Authors: Parthier L. , Schikora D. , Schäfer P. 
Published: January 2007

AbstractA theoretical model for the computation of the axial temperature distribution for the THM arrangement is described considering the heat flow in radial direction. The calculated temperature distribution is compared with the measured one. The correspondence is sufficient. By means of this model, it is possible to estimate the effect of a change of important growth parameters prior to the experiment. The model also permits a calculation of temperature distributions of other crystal growth methods (e.g. Bridgman, zone levelling, zone melting) by changing the boundary conditions only.
The effect of crucible movement in Bridgman‐Stockbarger technique
Authors: Sabharwal S. C. , Mirza T. , Karandikar S. C. , Ghosh B. 
Published: January 2007

AbstractThe effect of the crucible movement on the growth of large size alkali halide crystals effected in a ceramic crucible by B‐S technique is investigated. From the studies carried out it follows that the crucible movement adversely affects the thermal conditions in the furnace resulting in a defective growth. To circumvent the problems faced suitable modification of the conventional B‐S technique yielding good crystals is suggested.
Photovoltaic effect in polycrystalline ZnTe films
Authors: Patel S. M. , Patel N. G. 
Published: January 2007

AbstractAnomalous but weak photovoltaic effect has been observed in the case of thin polycrystalline ZnTe films obliquely deposited on glass substrate. Photovoltage of the order of a few hundred millivolt per centimeter have been observed at the ambient temperature. Optimized conditions for growing films to obtain maximum photovoltage have been found. In order to explain the observed photovoltaic effect, a model comprising of a long chain of aligned microcells in the form of pp+ homojunctions has been proposed. The implications are discussed.
Etch patterns on borax crystals
Authors: Takoo R. K. 
Published: January 2007

AbstractEtch patterns obtained on habit as well as cleaved matched faces of borax crystals are described. Morphology of all the etch pits is discussed. It is found that all the pits are formed at the sites of dislocations. A report about various dislocation configurations is given. From the dislocation density measurements, it is established that the borax crystals grown are of very good quality.
Stereological analysis of dislocation arrangements in crystals from TEM images
Authors: Hanisch K.‐H. , Klimanek P. , Stoyan D. 
Published: January 2007

AbstractIdeas of stochastic geometry have been used in order to develop procedures for stereological characterization of dislocation arrangements in crystals from TEM images. Two conceptions, which can be taken for promising in much cases, are presented in some detail: analysis of statistically homogeneous defect distributions by means of pair — correlation functions and interpretation of statistically inhomogeneous dislocation arrangements in terms of a so‐called Voronoi‐mosaic. Practical application of both methods is demonstrated by analysis of dislocation configurations occurring in metallurgy and solid‐state technology.
Superlattices and composition of phases of CVD layers based on TiCx, VCx, (Ti, V)Cx, and (Cr, Fe)7C3
Authors: Paulat E. , Lenk P. 
Published: January 2007

AbstractProtective layers of TiCx, VCx, (Ti, V)Cx, and (Cr, Fe)7C3 on C100W1 tool steel have been investigated by X‐Ray and electron diffraction. Superlattices have been observed in the VCx− and (Cr, Fe)7C3−layers. As manufacturing of (Ti, V)Cx−layers the growth of carbides with low content of V and Ti respectively has been prefered.
The importance of the oxygen ion concentration for oxidic high‐temperature solvents
Authors: Sinn E. , Linzen D. , Fischer K. 
Published: January 2007

AbstractUsing e.m.f. measurements we determined relative oxygen ion concentrations of the systems PbO—PbF2—B2O3, PbO—MoO3—B2O3, PbO—Bi2O3—V2O5, 3 PbO · MoO3—Fe2O3, and 3 PbO · MoO3—Ga2O3. Furthermore the alteration of the relative oxygen ion concentration of pure PbO was observed after stepwise addition of the solvent components PbF2, B2O3 and of the garnet forming oxides Fe2O3 and Y2O3 giving complete high temperature solutions for the Y3Fe5O12 preparation. Applying the Lux' acid‐base concept the behaviour of these oxide mixtures is discussed. Combinations which contain weak bases and weak acids allow the adjustment of a desired oxygen ion concentration that is little changed by added oxides for crystal growth. These combinations show favourable properties as solvents for oxidic substances with complicated compositions, e.g. perovskites, garnets, ferrites.
Some new electrically conducting complexes of nickel chelates
Authors: Oza A. T. 
Published: January 2007

AbstractSome new complexes of organo‐metallic nickel chelates with organic donors and acceptors and with halogens are found to have electrical resistivities lying in the semiconducting range. The results are discussed here briefly in terms of intermolecular interactions and molecular packing in the solid state. Ni3O2(OH)4 — a mixed valence nickel compound was found to have metallic conductivity in the form of single crystals.
Crystallization of hydrocarbon (n‐C28H58): Fatty acid (CH3(CH2)14COOH) mixtures
Authors: Prasad P. B. V. 
Published: January 2007

AbstractCrystallization of hydrocarbon (n‐octacosane), fatty acid (palmitic acid) and mixtures of hydrocarbon: fatty acid (n‐octacosane:palmitic acid) is carried out by the solvent evaporation method. The ability of palmitic acid to crystallize is compared with that of the hydrocarbon. Observations on the growth of palmitic acid as ring spherulites on the hydrocarbon crystal substrates is presented. Occurrence of alternatively bright and dark zig‐zag lines in some of the spherulites is attributed to a repeated twisting of the fibrous crystals of palmitic acid.
The silicon impurity as a possible growth‐regime indicator for LiNbO3 crystals
Authors: Erdei S. , Szaller Zs. , Raksányi K. , Matók Gy. 
Published: January 2007

AbstractThe influence of Si concentration and temperature regimes on the visually observable properties of LiNbO3 single crystals grown by Czochralski method was studied. Si concentration measurements were carried out and minima in the radial and axial distribution curves have been established. An upper estimate is given for the equilibrium distribution coefficient of Si in LiNbO3. A direct correlation has been found between the degree of opacity and the Si concentration. The variation of the Grashof number during growth and a correlated modification of the structure of the concentration layer width, implying a position dependent fulfilment of the Hurle‐Bardsley criterium for constitutional supercooling, accounts reasonably well with the visually observable properties of the opaque regions appearing in the course of crystal growth. The use of Si as an overall indicator for the characterization of growth regimes is discussed.
Structure of monoclinic acridine orange hydrochloride monohydrate, C17H19N3· HCl · H2O
Authors: Kuban R.‐J. , Kulpe S. , Schulz B. 
Published: January 2007

AbstractMr= 319.82, monoclinic P21/a,Z= 4,a= 14.545(5),b= 15.562(6),c= 8.538(4) Å, β = 120.66(3)°,V= 1662(1) Å3,Dm= 1.27 Mgm−3,Dx= 1.278 Mgm−3, λ(MoKα) = 0.71069 Å, μ(MoKα) = 0.24 mm−1,T= 297 K. FinalR= 0.049 for 1485 observed reflections. All hydrogen atoms were located and refined isotropically. Bond lengths (σ = 0.004 Å) and angles (σ = 0.3°) are normal. The substance is a derivative of acridine. The structure consists of chloride anions, bisdimethylaminoacridinium cations and water molecules. In the solid state the molecules are approximately planar. Pairs of cations form dimers with parallel planes connected by an I inversion centre and plane distances of 3.474 Å. They overlap with partial areas of all three six membered rings.
Effect of low temperature thermocycling on microhardness anisotropy of commercially pure beryllium
Authors: Lavrentev F. F. , Pokhil Yu. A. , Shayaeva Ch. Yu. 
Published: January 2007

AbstractCommerically pure beryllium polycrystals prepared by hot uniaxial crucible extrusion have been used for statistical investigation of the microhardness distribution on various faces distinguished by the orientation with respect to the extrusion axis. The microhardness anisotropy coefficient K (the relative difference of the statistical average values of microhardness for faces perpendicular and parallel to the extrusion axis) of the tested material was high. Low temperature thermocycling between 300 and 77 K essentially reduced K, which is thought to be a result of structural state changes and internal stress redistribution in the material induced by thermoeleastic stresses due to thermocycling.The result of the experiment is in qualitative agreement with data on the beryllium defect structure and fracture character found by transmission and scanning electron microscopy.
Determination of carbon, silicon and boron content in semi‐insulating GaAs by infrared absorption spectroscopy
Authors: Ulrici B. 
Published: January 2007

AbstractMeasurements of the local vibrational mode (LVM) absorption of 12CAs at 582 cm−1, 28SiGa at 384 cm−1 and (10)11BGa at (540 cm−1) 517 cm−1 can be used to determine the concentration of these residual impurities in semi‐insulating (SI) GaAs. Although the energy‐limited resolution of a grating spectrometer does not allow measuring the line shape of the narrow LVM bands in GaAs the intensity of it determined with definite spectral slit width (SSW) is a reliable measure for the respective impurity content. Calibration factors given in the literature and peculiarities in the measurements and evaluations for the different impurities are discussed.
A fluctuation theory of normal crystal growth in the case of one‐component metallic macrosystems
Authors: Chistyakov Yu. D. , Baikov Yu. A. 
Published: January 2007

AbstractA Model of spontaneous fluctuations of the limited spectrum solid state particle concentrations in the case of one‐component metallic macrosystems is considered. Within the small supercoolings' region of the melt‐crystal macrosystem a normal law of crystallization is established due to the action of fluctuation mechanism. For some metallic macrosystems a comparison on the crystallization kinetics between the theory and experiments has been realized. Some quantitative restrictions of the melt‐crystal system supercoolings' region within which the mechanism of spontaneous fluctuations is expected to be realized are established for a collection of one component metallic macrosystems. Two‐phase transitional zone length's influence on the values of admitted supercoolings in presented.
Partition coefficients of rubidium and cesium in the process of crystallization of the sodium chloride melt
Authors: Smirnova E. P. , Kravchuk I. F. , Tikhomirova E. I. 
Published: January 2007

AbstractPartition coefficients of rubidium and cesium between the crystal and melt of the sodium chloride have been determined by the directed horizontal crystallization and Czochralski methods. Rudidium and cesium partition coefficients were found to be constant in the studied concentration range < 1%, and insensitive to the presence of third microimpurity in the system. The theoretically calculated partition coefficients agree well with the experimentally measured coefficients.
Statistic analysis of partition coefficients for crystallization cleaning methods
Authors: Nisel'son L. A. , Yaroshevsky A. G. 
Published: January 2007

AbstractStatistic estimation of experimental determination reliability for the distribution coefficient, K, (crystal‐melt equilibrium) has been made on the basis of independent measurement comparison. Reliability of these data is shown to be low. Frequency K histograms have been constructed both for simple element set and halogenides. Histogram maximum shift to lg K < 0 has been obtained.
X‐ray powder diffraction and 1H‐NMR studies of phase transitions in tetra‐n‐butylammonium octacyanotungstate (V)
Authors: Czerwonka J. , Hodorowicz S. A. , Samotus A. , Kanas A. , Sagnowski S. , Rydzy M. 
Published: January 2007

Abstract[(n—Bu)4N]3 W(CN)8 is investigated by X‐ray powder and wide‐line proton magnetic resonance methods. The temperature dependences of the lattice parameters and 1H second moment of the resonance lines are recorded in the range of 77 to 383 K. On ground of the dynamical model proposed for the crystal lattice of the compound an analysis of the experimental data is made. The reorientations of different groups of the cations are proved to be responsible for the observed effects.
Interfacial stability and grain diameter of the metal phase of directionally solidified Al‐Si‐type eutectics
Authors: Vetter Jörg , Schmidt Günther , Frühauf Joachim 
Published: January 2007

AbstractThe morphology of the solid‐liquid interface and the metal phase grain diameter of Al—Si‐type eutectics (Al—Si, Ag—Si, Ag—Ge, Zn—Ge) were investigated in the range of a growth rate R = 0.2 … 20 mm/h and of a temperature gradient at the solid‐liquid interface G = 2 … 25 K/mm. Three types of interfacial morphologies depending on the G/R ratios were found out. The G/R ratio of the transition from a planar to a nonplanar solid‐liquid interface corresponds to the critical G/R|c ratio, which can be calculated by the criterion of the constitutional undercooling. The grain diameter of the metal phase depends on growth parameters as follows: dK ∼ R—rG—g with r = 0.33 … 0.43 and g = −0.37 … 0.03.
Chemical and LP‐etching of gallium antimonide substrates
Authors: Pramatarova L. D. , Baeva M. B. , Yordanova I. M. 
Published: January 2007

AbstractThis paper presents the results of the chemical and Liquid Phae (LP) Etching of the GaSb substrates. The method of anomalous transmission for X‐ray topographic imaging of dislocations was used. It is shown that the dislocation density lowers with decreasing of the Sb content in the Ga melt at the LP‐etching.
Induced smectic A phase by homeotropic orientation in 4, n‐octyloxybenzoic acid (OOBA) at nematic‐smectic C phase transition
Authors: Simova P. , Petrov M. 
Published: January 2007

AbstractUsing homeotropic and quasi‐homeotropic orientation in thin film of 4‐n‐octyloxybenzoic acid, we indicated intermediate smectic A‐like state during the nematic‐smectic C phase transition. Pseudoisotropic and focal conic textures are characteristic for homeotropic and quasihomeotropic orientations respectively. The smectic A‐like state induced by the boundary conditions exists in a very short (about 0.5 °C) temperature region.
Heat and mass transfer problems in solution growth of GaP crystals by the travelling solvent method (TSM)
Authors: Nghi Nguyen Thanh 
Published: January 2007

AbstractThe influence of the natural convection on the heat and mass transfer process during growth of GaP crystals from the solution is considered. The two‐dimensional quasi‐stationary thermodiffusive hydrodynamic problem for the GaP growth system by travelling solvent method (TSM), as a model, has been solved. Computation is given for the temperature and concentration field distribution in the solution. The picture of vortex configuration for different lengths of the liquid zone, the shape of the growing and dissolving interfaces and also the boundary layers thickness are obtained. The experimental dependence of the growth rate on the convection intensity observed mostly confirmed the calculation results.
Crystallization of hydrocarbon (n‐C28H58): Fatty acid (CH3(CH2)14cooh) mixtures (II). The thermal effect
Authors: Prasad P. B. V. 
Published: January 2007

AbstractStudies on the crystallization of mixtures of palmitic acid: n‐octacosane at elevated temperatures is presented. The crystallization temperature is seen to have a pronounced effect on the morphology of the banded structures. The fibre twist which is responsible for the band formation, is interpreted as due to a thermal stress. Crystallization of some other compounds in the presence of n‐octacosane is described and the results are discussed.
Microscopic investigations of morphological structures on the pyramidal faces of KDP and DKDP single crystals
Authors: Hilscher H. 
Published: January 2007

AbstractStudying a number of {101} faces of KDP and DKDP single crystals in the as‐grown state we found in most cases one, rarely few, clearly stepped growth hillocks covering the whole face. The geometry of these growth hillocks was determined from photomicrographs; the step heights were measured with a profilometer. To prove our results we carried out X‐ray topographic investigations and in‐situ observations on KDP crystals. In addition we studied the as‐grown faces of ADP and LiJO3 single crystals.
A new method for determining the thickness and composition of thin layers by electron probe microanalysis
Authors: Hunger H.‐J. , Baumann W. , Schulze S. 
Published: January 2007

AbstractA new method is described which allows the determination of thickness and composition of thin layers by EPMA simultaneously. The method is based on new depth distribution functions of the characteristic X‐rays and on a substrate correction which was developed by the authors. The test of this method with the aid of wellknown layers gives very good results. The method works with massive standards. Layers for calibration are not needed.
On the quench‐sensitivity of AlZn alloys during RT‐ageing in dependence on alloy composition
Authors: Hübner G. , Löffler H. 
Published: January 2007

AbstractThe quench‐sensitivity (variation of Tq) of the decomposition rate at RT was studied for four AlZn(X) alloys (X = 3.0; 4.5; 8.0, and 12.0 at. %) by SAXS. It was found that the occurring “inversion temperature” depends on alloy composition and, particularly for the two alloys with the highest zinc content, on ageing time.
The local distribution of luminescence generation in LED's
Authors: Oelgart G. , Stegmann R. , Kaatsch D. 
Published: January 2007

AbstractMit Hilfe der Temperaturabhängigkeit der Katodo‐ und Injektionslumineszenzintensität wird die lokale Verteilung der Lichtgeneration in lichtemittierenden GaAs1−xPx‐Dioden als Funktion des Flußstromes und der Herstellungstechnologie untersucht. Für geringes Injektionsniveau rekombinieren die Überschußladungsträger in einer hochkompensierten Schicht während mit steigendem Flußstrom das Licht im Volumen des n‐ und p‐Gebietes generiert wird. Das Injektionsverhältnis wird durch die Herstellungstechnologie des p‐n Überganges bestimmt.
Investigation for ferroelectric domains by scanning electron microscopy
Authors: Röder A. , Scheiding C. 
Published: January 2007

AbstractExamples for the direct observation of domain structures in ferroelectric crystals by means of scanning electron microscopy are given. The results for TGS and AFB crystals with direction of the polarization vector perpendicular to the observed surface are presented with respect to temperature changes, to domain enlargement under the influence of an external electric field and to the influence of X‐ray‐ and γ‐radiation on the domain formation.
Thermotropic liquid crystalline compounds with lateral long‐chain substituents (IV). Physical properties of 1,4‐bis‐[4‐n‐octyloxybenzoyloxy]‐2‐n‐alkylbenzenes
Authors: Demus D. , Diele S. , Hauser A. , Latif I. , Selbmann Ch. , Weissflog W. 
Published: January 2007

AbstractIn 15 Substances of general formula magnified image transition temperatures, transition enthalpies and entropies, densities and phase transition volumina, order parameters of a dissolved dye and optical refractive indices were measured. Additional miscibility and X‐ray investigations were performed. The results are discussed on the basis of molecular statistical theories of the nematic state and point to a conformation of the long lateral chains which is nearly parallel to the molecular long axes. The results further show the dominating importance of the steric repulsive forces in stabilizing the nematic state.