bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short‐Range Order in FeCrNi Alloys
Authors: Braude I. S. , Pecherskaya V. I. , Bolshutkin D. N. , Chernik M. M. 
Published: January 2007

AbstractThe short‐range atomie order in Fe82−xCr18Ni−x (x = 15, 20, and 25 wt%) alloy single crystals has been studied by the x‐ray diffuse scattering technique. Diffuse ring around the central node was found for all alloys. Analysis of the intensity distribution allowed to determine the short‐range order partial parameters. Correlations in atom arrangements in the regions of about 10–12 Ångstrom in diameter were found to be characteristic for the alloys studied. It is assumed, that regions of the structural short‐range order become magnetic clusters at the sufficiently low temperatures.
AgGaSe2 on {100} and {110} GaAs—Special Features of Epitaxial Growth
Authors: Tempel A. , Schumann B. 
Published: January 2007

AbstractAgGaSe2 thin epitaxial layers onto {100} and {110} oriented GaAs substrates were prepared by flash evaporation technique and investigated by the RHEED method (reflection high energy electron diffraction). Special epitaxial relationships were found and the results will be discussed.
Electrical Conductivity and Crystal Structure of Pure and SrCO3‐doped K2CO3
Authors: Guth U. , Babwisch F. , Wulff H. , Möbius H.‐H. 
Published: January 2007

AbstractElectrical conductivity of pure and SrCO3 doped potassium carbonate has been investigated in the temperature range between 350 and 800 °C. Sintered carbonate mixtures were analysed by X‐ray powder diffraction techniques at room temperatures. The conductivity of SrCO3 doped K2CO3 increases nearly linear up to 10 mol.% and decreases in the range between 20 and 50 mol.% continously. X‐ray diffraction patterns do not show changes up to 10 mol.% SrCO3 in the host lattice. The compound K2Sr(CO3)2 was found for samples containing 15–50 mol.% SrCO3. The lattice constants of hexagonal crystals which are isotypic with K2Ca(CO3)2 are a0 = (534 ± 1) pm and c0 = (1352 ± 2) pm.
Studies on Surface Structures and Etch Patterns on Habit Faces of Gel‐grown Crystals of Iodates of Barium, Strontium, and Calcium
Authors: Joshi M. S. , Trivedi S. G. 
Published: January 2007

AbstractMicrotopographical studies on habit faces of gel grown crystals (of different habits) of iodates of Ba, Sr, and Ca are illustrated and described. Etch patterns on these faces are illustrated and correlated to the observed growth patterns on the respective faces. Growth mechanism of the crystals is explained in light of the observed surface structures and etch pits suitably produced.
Plasma Etching of Niobium‐SiOxLayers
Authors: Schelle D. , Tiller H. J. 
Published: January 2007

AbstractCF4‐plasma etching of niobium and SiOxlayers has been investigated in a r.f. diode reactor. Etch rates increase linearly with increasing power density and also increase with pressure. The etch rate ratio can be changed using different etch gases or operating in different plasma modes (PE or IEPE). Changing from the ion enhanced plasma etching mode (IEPE) to plasma etching mode (PE) the etch rate ratio is changing by an factor of ten.On the basis of etch rate dependences on process parameters and thermodynamic data it has been suggested the generation of flourine radicals as the rate limiting step. A general etching model has been proposed, which explains qualitavelty and quantitatively (on account of data from literature) the measured results.
The Structure of 4‐n‐Hexyle‐6‐(4‐cyanophenyl)‐1,5‐diazobicyclo [3.1.0]‐hexanone‐(2), C17H21N3O
Authors: Kulpe S. , Seidel I. , Menz I. , Geissler G. , Tomaschewski G. 
Published: January 2007

AbstractMr = 283.2; monoclinic, P 21/c, a = 9.631(7), b = 21.268(16), c = 8.488(8) Å, β = 107.13(9)°, Z = 4, V = 1661.8(9) Å3, Dx = 1.42 Mg m−3, final R = 0.134 for 605 independent reflections excluding those with |Fo| < 3σ|Fo|). Intensities were measured with an automatic diffractometer. The compound is a product of a photoreaction. The five membered ring and the three membered ring of the bicyclic diaziridine group and the six membered ring of the 4‐cyanophenyl group are nearly perpendicular one to another. The 4‐cyanophenyl group is in exo‐position to the five membered ring of the bicyclic diaziridine group. The C(4) atom and the aliphatic hexyle group are in respect to the five ring in trans‐position.
Crystallization and Separation of Pentaerythritol from Lubricating Oil Dispersant Additives
Authors: Najim N. A. R. , Barker P. E. 
Published: January 2007

AbstractThe experiments and techniques used in the study of the crystallization characteristics of pentaerythritol (PE) from a certain lubricating oil dispersant additive are presented. These experiments were performed with a view to improving the filtrability of the dispersant product and also to reduce the potential for sediment formation in the dispersant product during storage. Successfully tested methods for the elimination of this sediment formation at storage are also presented.
Physical Properties of Liquid Crystalline 5‐n‐Hexyl‐2‐(4‐n‐alkyloxyphenyl)‐pyrimidines
Authors: Hauser A. , Selbmann Ch. , Rettig R. , Demus D. 
Published: January 2007

AbstractIn 8 compounds of the substance class 5‐n‐hexyl‐2‐(4‐n‐alkyloxyphenyl)‐pyrimidines the clearing temperatures, transition enthalpies, densities and refractive indices were measured. Packing fractions, pressure dependence of the clearing temperatures, polarizabilities, order parameters and the anisotropy of the local field were calculated.
Effect of Fast Electron Irradiation and Annealing on the Luminescence in GaAs(Zn) crystals. Irradiation‐induced 1.26 and 1.39 eV Emission Bands
Authors: Glinchuk K. D. , Guroshev V. I. , Prokhorovich A. V. , Zayats N. S. 
Published: January 2007

AbstractThe effect of 2.2 MeV electron irradiation and subsequent annealings on the photoluminescence in zinc‐doped p‐type GaAs crystals is studied and analyzed. Rather strong emission bands peaked at hvm (77 K) near 1.26 eV (induced by electron irradiation) and 1.39 eV (induced by annealing of irradiated crystals) are observed. Evidence is presented that the 1.26 and 1.39 eV emission bands occur due to radiative electronic transitions in AsiZnGa and VAsZnGa pairs induced by irradiation and annealing of irradiated crystals, accordingly. The observed variations in the intensities of the 1.26 and 1.39 eV emission bands upon irradiation and subsequent annealings of GaAs(Zn) crystals are explained in terms of irradiation and annealing‐induced variations in the amount of 1.26 and 1.39 eV radiative centres resulting from: a) the effective interaction of mobile radiation‐induced defects in the arsenic sublattice with zinc atoms leading to the formation of AsiZnGa and VAsZnGa pairs; b) the thermal dissociation of AsiZnGa and VAsZnGa pairs on individual components.
Crystal Growth from Silica Gels and Single Crystal Structure of Bariumchromate
Authors: Lentz A. , Büchele W. , Schöllhorn H. 
Published: January 2007

AbstractRhombic single crystals of bariumchromate were grown in silica gels up to 1.5 mm in size. The influence of the initial pH‐value of the gel and the kind and concentration of reactants are studied. The crystal structure has been determined. The compound crystallizes in space group Pnma, with cell dimensions a = 9.113(4) Å, b = 5.528(3) Å, c = 7.336(4) Å and Z = 4. The structure was refined to R = 0.062 on the basis of 364 reflections. Every barium atome, centered in a distorted archimedian antiprism, is coordinated to 8 oxygen atoms each belonging to a chromate tetrahedron. Interatomic distances and bond angles were calculated.
Studies on Induced Smectic Phases (VI). The Role of the Ratio of the Molecular Lengths in Binary Mixtures of Smectogens
Authors: Szabon J. , Weissflog W. , Pelzl G. , Diele S. , Demus D. 
Published: January 2007

AbstractIn a number of binary systems composed of liquid crystalline terminal‐polar and terminal‐nonpolar compounds the SA phase induction was studied in dependence of the molecular length ratio r of the mixing components. It was found that there is a connection between the maximum temperature of the SAN or SA‐Is transition curve and the molecular length ratio r. Up to a certain ratio the smectic induction increases and after that it reaches a saturation.The studies were completed by X‐ray and calorimetric measurements in selected binary systems.
Influence of γ‐Irradiation on Some Properties of NaCl:Eu++ Crystals (III). Strengthening Effects
Authors: Suszyńska M. , Czapelski M. 
Published: January 2007

AbstractMechanical strength of europium‐doped NaCl crystals was studied as function of dopant concentration and dopant dispersion state as well. It has been found that the yield stress of the solution‐treated samples is determined by the Snoek‐type reorientation of dipoles in the stress field of moving dislocations. For as received samples the precipitation strengthening mechanisms are postulated.Irrespective of the dispersion state of europium, the strength of all NaCl:Eu++ crystals can be remarkably changed by the room temperature irradiation. Although the yield stress increments can be explained in frames of the precipitation‐strengthening mechanisms, the radiation‐induced processes depend on the primary disprsion e state of the dopant. As far as the solution‐treated samples the clustering of I.V. dipoles is of main importance, it is necessary to assume that dispersion of precipitates is required to achieve the strength of irradiated as received samples.
Crystal and Molecular Structure of the Smectogen 1‐[4‐n‐heptylbenzoyl]‐2‐[cyanoacetyl]‐hydrazine
Authors: Pfeiffer Doris , Kretschmer Rolf‐Günter , Hoffmann Siegfried 
Published: January 2007

AbstractThe compound 1‐[4‐n‐heptylbenzoyl]‐2‐[cyanoacetyl]‐hydrazine crystallizes in the triclinic space group Pl̄ with two molecules in the unit cell and the lattice parameters a = 4.702, b = 8.640, c = 20.906 Å, a = 97.50, β = 92.79, γ = 100.19°. The structure was solved by direct methods and refined by full‐matrix least squares calculations to the final residual value R = 0.039.
The Problem of a Near Surface Quasi‐Gas Transition Layer in MBE
Authors: Herman M. A. 
Published: January 2007

AbstractA survey of experimental data related to the problem of a near surface quasi‐gas (NSQG) transition layer in molecular beam epitaxy (MBE) has been presented and the arguments suggesting the existence of such a transition layer have been discussed. Subsequently, the application of the NSQG layer concept to morphological stability analyzis of MBE and to the phase‐locked MBE has been discussed. The experimental data presented suggest that in growing extremely flat layer structures, e.g., superlattice structures, a growth mode for MBE should be chosen in which the NSQG layer is maximally thin, however, when growing planar epilayers over patterned substrates such MBE growth mode should be chosen in which the creation of a thick (on an atomic scale) NSQG layer would be possible.
Kinetics of Etching of Dislocations in Ferroelectric Ammonium Hydrogen Tartrate Single Crystals
Authors: Desai C. C. , Hanchinal A. N. 
Published: January 2007

AbstractFerroelectric crystals of Ammonium Hydrogen Tartrate (AHT) have been synthesised using the controlled reaction between NH4Cl and (CHOHCOOH)2 by diffusion process in silica gel medium. (010) cleavages of AHT crystals have been etched in 1.0 M and 1.5 M solutions of SrCl2 solution. The lateral and normal velocities of the growth of pits were measured at different temperatures. The time dependence of the growth of the pit dimensions is found to be linear, whereas the temperature dependence of the growth of pits is found to be exponential, viz. \documentclass{article}\pagestyle{empty}\begin{document}$ \[V = A\,\exp \left({\frac{E}{{kT}}} \right)\] $\end{document}. The dissolution parameters, e.g. the activation energies and the pre‐exponential factors for dissolution along the surface and along the dislocation lines have been computed. It is observed that the activation energy (E1) of dissolution along [001] direction is found to be greater than the activation energy (Eb) along [100] direction and the implications are discussed.
Peculiarities in the X‐ray Spectral Microanalysis of the SnTeI System
Authors: Assenov R. , Moshnikov V. , Patarov B. , Yaskov D. 
Published: January 2007

AbstractThis is an examination of the methodological specificities of the roentgenospectral microanalysis of the SnTeI system, involving the application of a graphoanalytical method used in the analysis of ternary systems according to data calculated for the binary ones. The calculations were made on an ES 1060 computer in FORTRAN‐4. The calculations are for different selection angles of the microanalyzer, and for a broad interval of values of the accelerating voltage. In this manner the method offered is applicable to any type of microanalyzer, and not only to the Cameca MS‐46 used by us.
Liquid Phase Epitaxy of SiC in the System TbSiSiC by Temperature Gradient Zone Melting (II). Liquid Phase Epitaxy of SiC from TbSi Solvent
Authors: Peev N. S. , Tairov Yu. M. , Smirnova N. A. , Kalnin A. A. 
Published: January 2007

AbstractThe liquid phase epitaxy of SiC by the gradient temperature zone melting in the SiTb solvent is studied. A new variant of this growth method is presented. The comparison of the new variant with the previous one shows that the new variant allows for epitaxial layers with significant better electrophysical properties. It is easier and can be carried out at lower temperature.
Structure of the OD‐disordered 2‐Hydroxy‐4‐methoxy‐2H‐1,4‐benzoxazin‐3‐one, C9H9NO4
Authors: Kutschabsky L. , Kretschmer R.‐G. , Schrauber H. , Dathe W. , Schneider G. 
Published: January 2007

AbstractThe X‐ray diagrams of the title compound show pronounced maxima on diffuse streaks parallelc* and unusual extinctions. The intensity distribution is compatible with the assumption of a disordered (OD) structure consisting of one kind of layers. The structure contains ordered domains with the crystal data: monoelinic, space group P 21/a, lattice parametersa= 15.910(5),b= 8.365(4),c= 15.747(5) Å, β = 120.34(6)°,V= 1809 Å3,Z= 8,Mr= 195.1,Dx= 1.432 Mg m−3, μ(MoKα) = 0.36 mm−1, finalR= 0.129 for 859 observed reflections. The asymmetric unit is constituted of two crystallographically independent molecules related by a pseudo glide plane. The crystal used for X‐ray analysis proved to be twinned.
Investigation of the Crystalline State of Identical Sample Domains by Means of Divergent X‐ray Beam Technique in the Direction of Transmission and Reflection in the Scanning Electron Microscope (SEM)
Authors: Däbritz Siegfried , Horn Herwig R. , Kleinstück Karlheinz , Waltinger Hanns , Hoffmann Volker 
Published: January 2007

AbstractA supplementary device to a scanning electron microscope allows the simultaneous taking of wide‐angle interferences in the directions of transmission and back reflection of identical specimen areas. A developed computer program simulates the complete reflex system so that the identity with the pattern is obtained. This results, on the one hand, in qualitative and quantitative statements concerning the real structure of the specimen and, on the other hand, shadings of reflexes caused by the target holder tube can be distinguished from interruptions of reflexes caused by the grain size effects. The efficiency of the supplementary device for the characterizing of mono‐ and polycrystalline specimens is demonstrated by several examples.
X‐Ray Study of the Reaction Products in Tin Telluride Synthesized by a Low‐Temperature Iodide Method
Authors: Assenov R. , Moshnikov V. A. , Saunin I. V. , Yaskov D. A. 
Published: January 2007

AbstractAn examination is made of the separate stages of obtaining SnTe by the low‐temperature iodide method, involving X‐ray studies of the reaction products after each stage. It is demonstrated that the tin iodide, released at the isothermal annealing of the initial charge in the reactor, is in the form of SnT4, and not SnT2 as had been considered before.
Study of the Electronic Absorption Spectrum of Crystals of Transition Metal Iodate
Authors: Jianmin Li , Yongfeng Zhang , Jifa Fang 
Published: January 2007

AbstractThe electronic absorption spectra of spherocrystals of Ni(IO3)2 · 2 H2O, Mn(IO3)2 and 3 Cu(IO3)2 · 2 H2O were measured. Some new absorption peaks were obtained. Measured energy splitting by low‐symmetric crystal field and spin‐forbidden transitions are clearer than the results of diffuse reflection spectrum. And the experimental results were interpreted theoretically by means of nonfree radial wave functions and ligand field theory. The experimental results and the calculated values coincide.
Suppression of epitaxial silicon layer doping with boron in the presence of hydrogen chloride
Authors: Morgenstern Th. , Kühne H. , Kokovin G. A. , Testova N. A. , Titov A. A. 
Published: January 2007

AbstractThe present paper informs about thermodynamic calculations of the BClH system, carried out irrespective of data, already published by other authors. It further deals with recent experimental results on silicon doping with boron in the presence of hydrogen chloride, the layer growth rate being varied. Finally the possibility of quantitatively interpreting the suppressing influence of hydrogen chloride on the doping of silicon with boron is discussed.
Phenomenon of the maximum inhomogeneity in solidification of alloys from the peritectic‐eutectic phase systems
Authors: Wołczyński W. 
Published: January 2007

AbstractAn application of the Scheil equation with the purpose to: 1 describe the maximum dendritic microsegregation phenomenon, i.e. amount of the solid solution in function of the initial composition of alloys from the AgSb phase system, 2 determine the nature of the maximum microsegregation in the Ag–30 Sb and Ag–10 Sb alloys is presented.A new relation, supplementary to the Scheil equation is proposed.
Characterization of water‐containing alunite (loewigite)
Authors: Aslanian S. , Minkova N. 
Published: January 2007

AbstractChemical analyses, IR‐spectra, differential‐thermal analyses and X‐ray diffraction studies of water‐containing alunite were carried out. These results were compared with those obtained for alunite. Group‐theoretical analyses of the vibrational spectra of alunite were performed. It is shown that water‐containing alunite has a structure similar to that of alunite, but inclusion of water molecules causes a lowering in symmetry and explains differences in the mineralogical characterizations of both alunites.
Reduction of crystal surface roughness to augment anti‐Caking Properties
Authors: Sarig S. , Fuchs J. , Kahara F. 
Published: January 2007

AbstractAmmonium bromide crystals were grown in quiescent and stirred batch systems and in a continuous laboratory crystallizer at steady state. Urea was added in concentration of 5–20 ppm. The crystals were filtered out, dried, sieved and inspected by Scanning Electron Microscope. The effect of urea was evaluated by comparison between crystals grown by one of the techniques without an admixture and those grown within the presence of urea.In quiescent batch solution pure ammonium bromide crystals grow in fern‐like large dendritic forms. Urea suppresses the characteristic branching. Stirring changes the habit into aggregates of small globular crystals. The addition of urea to a stirred batch system causes growth of separate ovoid crystals.In a continuous crystallizer, at steady state conditions seemingly loose agglomerates of ammonium bromide are formed. No change visible at low magnification is brought forward by the addition of urea. However, at high magnifications the crystal surface of the pure ammonium bromide is brush‐like and rough, retaining the dendritic tendencies in the range of microscopic sizes. The addition of urea smoothes the surface.The roughness of the pure ammonium bromide surfaces may explain its strong caking tendencies. Reduction of the roughness will probably decrease the caking in the polycrystaline mass. This assumption has to be checked in industrial production.
Growth of tartrate crystals of type R2 (C4H4O6)3 · xH2O (R = Nd, Dy) in silica gel
Authors: Kotru P. N. , Raina K. K. , Gupta N. K. 
Published: January 2007

AbstractSpherulitic crystals of neodymium and dysprosium tartrates have been grown by controlled diffusion in silica gel. The operative mechanisms of crystallization are discussed and the morphological development of the spherulites is described. The adsorption property of gel is observed to play an important role in the growth of the spherulitic crystals.
Growth and microscopic studies of yttrium aluminium garnet single crystals
Authors: Kumar J. , Thirumavalavan M. , Gnanam F. D. , Ramasamy P. 
Published: January 2007

AbstractA study has been made to understand the growth history and growth mechanism of flux grown yttrium aluminium garnet (YAG) single crystals. Etching has been done to reveal the growth patterns of flux grown crystals. Optical and scanning electron micrographs are presented. Optical micrographs were taken under polarised light and oblique incident light. The nature and origin of growth hillock is elucidated.
Oxidation of solid aluminium silicon alloys in air
Authors: Yaneva S. , Stojanova L. , Markov T. 
Published: January 2007

AbstractThe kinetics of oxidation of solid Al–Si alloys in air was studied at temperature interval between 490 °C and 532 °C. The initial time intervals in which oxidation is governed by a parabolic quadratic low were found form the weight time‐gain curves. At temperature higher than 512 °C the exponent of the parabolic ratio differs from 2.It was shown the influence of the alloying element Si on the oxidation and the effective activation energies of oxidation of AlSi alloys were calculated. They are considerably higher than the effective activation energies for pure aluminium.
Characterisation of MoSexTe2−x (0 ⩽ x ⩽ 2) electrodes in terms of energetic location of valence and conduction bands
Authors: Agarwal M. K. , Patel P. D. , Joshi R. M. 
Published: January 2007

AbstractThe layer type MoSexTe2−x (0 ≦ x ≦ 2) has been grown by chemical vapour transport technique. The photoelectrochemical solar cells have been fabricated using the grown crystals as photoelectrodes and platinum grid as counter electrode in aqueous iodine/iodide solution. The optical band gap determination has been done from the study of the spectral response of the cells. The location of valence and conduction band edges and flat kind potentials have been evaluated using Mott‐Schottky plots.
Crystal structure determination of bis‐dimethyl heptamethine cyanine chloride, C11N2H19Cl · 4 H2O
Authors: Kulpe S. , Kuban R.‐J. , Schulz B. , Dähne S. 
Published: January 2007

AbstractMr = 286.59, monoclinic superposition structure C 121,Z= 4,a= 15.248(3),b= = 6.942 (3),c= 9.074(1) Å, β = 120.1(1)°,V= 827(1) Å3,Dm= 1.13(1) Mg m−3,Dx= = 1.15 Mg m−3, λ(MoKα) = 0.71069 Å, μ = 0.243 mm−1,F(000) = 312,T= 296 K, finalR= 0.061 for 802 reflections. All hydrogen atoms were located. The structure consists of chloride anions, bis‐dimethyl heptamethine cyanine cations and water molecules. The structure of bis‐dimethyl heptamethine cyanine chloride is disordered, e.g. there exist partial coincidence operations, leading to more than one stacking mode of the bis‐dimethyl heptamethin cyanine chains. The crystal structure consists of rows of molecule along thea‐axis. The CC bonds show the bond length compensation, typical of polymethines, towards a partial double bond (mean value 1.38 Å) between formally sp2‐hybridized C atoms. The CN bond lengths to the methyl carbon atoms (mean value 1.49 Å) correspond to normal CN single bonds. The valence angles at the C atoms of the heptamethine chain clearly alternate and deviate systematically from 120°. This is also observed in other structures of a similar type.The structure determined by X‐ray analysis confirms the chemical results.