bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Physical Constants of the Melt and the Parameters of the Control Object Concerning Crystal Growth from the Melt
Authors: Satunkin G. A. , Red'kin B. S. , Kurlov V. N. , Rossolenko S. N. , Tatarchenko V. A. , Tuflin Yu. A. 
Published: January 2007

AbstractNew Techniques are presented for the determination of the capillary constant and the coefficient of thermal expansion of the melt using an electrocontact sensor (ECS). The density of the melt, the capillary constant, the coefficient of the thermal expansion of the melt, the growth angle, and the characteristic time of thermal relaxation of the thermal zone are determined for the case of growing the lithium niobate crystals by Czochalski technique.
Crystal and Molecular Structures of Modified Progestagens (II). 17α‐Azidomethyl‐17β‐hydroxy‐cstr‐4‐en‐3‐one, C19H27N3O2
Authors: Reck G. , Hübner M. , Bohl M. , Leibnitz P. 
Published: January 2007

AbstractThe crystal and molecular structure of the title compound has been determined by X‐ray structure analysis. It crystallizes in the orthorhombic space group P 212121. The lattice constants are α = 9.409(2), b = 9.799(2), and c = 38.664(13) Å. The structure was solved by MULTAN‐82 and refined to R = 0.056 for 1933 observed reflections. There are two molecules, A and B, in the asymmetric unit with partly different steroid ring conformations. O17AH… O3B and O17BH… O3 A′ hydrogen bonds link the molecules into chains parallel to c.Die Kristall‐ und Molekülstruktur der Titelverbindung wurde mit Hilfe der Röntgenkristallstrukturanalyse bestimmt. Die Verbindung kristallisiert in der orthorhombischen Raumgruppe P 212121. Die Gitterkonstanten sind a = 9.409(2), b = 9,799(2) and c = 38,664(13) Å. Die Struktur wurde mit MULTAN‐82 gelöst und bis zum R‐Wert von 0,056 für 1933 beobachtete Reflexe verfeinert. Es gibt zwei Moleküle, A und B, in der asymmetrischen Einheit mit teilweise verschiedenen Steroidkonformationen. O17H… O3B und O17BH… O3A′ Wasserstoffbrücken verbinden die Moleküle zu Ketten parallel zu c.
Structural Studies of Antimony Pentahalide Graphite Intercalation Compounds Using 001 Reflections
Authors: Ppreiss H. , Fichtner‐Schmittler H. 
Published: January 2007

AbstractX‐ray diffraction studies at room temperature are reported of stages 1, 2 and 3 SbClmF5‐m graphite intercalation compounds (m = 0, 2, 4, 5). The analysis of the 001 reflection inten‐sities shows the periodic stacking of carbon, chlorine and antimony layers in all compounds. The results are in good agreement with the structural model recently found in other metal halide graphites. But we have found that the antimony atoms are not located on the mirror plane (z = O) in the centre of the intercalate layer. In case of dilute SbCl5 graphites, the identity period along c axis Ic increases with SbCl5 concentration in the stage 2 com‐pound. Interlayer distances were determined in dependence on SbCl5 concentration. A molecular layer form consisting of SbX5 molecules which are linked by halogen bridges is suggested to fill the galleries in the graphite lattice.
The Effect of Plastic Deformation on the Real Structure of ZnO Crystals during the Growth Process
Authors: Vladimirov V. I. , Kuz'mina I. P. , Loshmanov A. A. , Regel' V. R. , Sizova N. L. , Chernysheva M. A. , Kostyukov E. P. , Smirnov I. S. , Shaldin Yu. V. 
Published: January 2007

AbstractThe rotational model for ZnO plasticity under the action of concentraion stresses is given on the ground of the real structure analysis (the presence of two scales of the crystal lattice disorientation, a change of the ZnO crystal lattice parameter and the presence of disorientation boundaries of different types). Concentration stresses estimated at the Tgr. \documentclass{article}\pagestyle{empty}\begin{document}$ \tau = G\varepsilon = G\frac{{\Delta a}}{a} \approx 20 $\end{document} MPa exceed the yield point of crystals at Tgr. and may be the cause of rotational plasticity development.
Failure Distribution on Semiconductor Wafers
Authors: Kopelmann A. , Enders P. , Knauer A. , Bärwolff A. 
Published: January 2007

AbstractInvestigation of the distribution of dislocations intersecting the free surface of (1, 0, 0), Si‐doped Bridgman‐grown GaAs wafers. The defect densities were determined by using molten KOH as the defect‐revealing etch. Their distribution can well be described by the compound Poisson‐gamma distribution. The corresponding formula for the chip‐yield is derived and it is shown, under which conditions it goes over into that for the simple Poisson distribution. Further, it is shown how the finite dimension of failures can be taken into account.
Analysis of the Dynamics of the Controlled Crystallization Process Using the Czochralski Method
Authors: Satunkin G. A. , Rossolenko S. N. 
Published: January 2007

AbstractA mathematical model proposed for the Czochralski method has been employed to analyse the stability, to calculate the transitional characteristics of open and closed systems for the case that the PID control is used in the feedback circuit. The method to control the crystallization process by weighing the crystal is analysed in detail. Based on the proposed criterion of quality of the transitional process, an optimum adjustment of the controller for one‐ and two‐channel control is performed.
Growth and Electron Microscopical Investigations of (CaBa)F2 Epitaxial Layers on GaAs and InP Substrates
Authors: Schumann B. , Kühn G. , Wagner G. 
Published: January 2007

Abstract(CaBa)F2 layers have been grown on (100)‐oriented GaAs and InP substrates by flash evaporation technique. They were investigated by means of electron microscopical methods (RHEED, TED, TEM). Epitaxial growth was found at temperatures in the range of 725 to 825 K for GaAs substrates and 700 to 800 K for InP substrates, respectively. The films showed a fine‐grained structure and consisted of two phases always with a composition of approximately Ca0.99Ba0.01F2 and Ca0.08Ba0.92F2. This is in accordance with the occurrence of a miscibility gap observed in the binary CaF2BaF2 system.
Nucleation Studies in Supersaturated Triglycine Sulphate Solutions
Authors: Natarajan V. , Gnanam F. D. , Ramasamy P. 
Published: January 2007

AbstractRates of nucleation of supersaturated aqueous solutions of Triglycine sulphate are measured by the induction period over the temperature range 30–50 °C. The effects of temperature and supersaturation on the induction period are reported. The interfacial tension, energy of formation and radius of the critical nuclei of the crystal are calculated in accordance with classical nucleation theory. Nucleation rate increases with increase in supersaturation and temperature, while interfacial tension decreases with increase in temperature.
Secondary Nucleation of Ammonium Alum in the Presence of Insoluble Additives in the Solution
Authors: Teodossiev N. 
Published: January 2007

AbstractSecondary nucleation of ammonium alum has been investigated in seeded batch crystallization from aqueous solutions. The presence of a time lag is established during which the nucleation rate increases up to a constant value. The duration of the time lag increases with increasing supersaturation. The effect of fine heteroparticles of alumina and silica on the rate of secondary nucleation is studied. The heteroparticles slightly increase the nucleation rate but cause the appearance of a considerable number of new nuclei when introduced some time after the process beginning. An assumption is made that the heteroparticles mainly affect the surviving of non‐growing nuclei without changing the actual rate of secondary nucleation.
Crystal and Molecular Structures of Modified Progestagens(III). 17α‐Chloromethyl‐17α‐hydroxy‐estr‐4‐en‐3‐one, C19H27CIO2
Authors: Reck G. , Hübner M. , Pfeiffer D. 
Published: January 2007

AbstractThe crystal and molecular structure of the title compound has been determined by X‐ray structure analysis. It crystallizes in the monoclinic space group P 21 with cell parameters a = 11.471(1), b = 17.261(3), c = 8.680(2) A, and β = 92.39(1) A. The structure was solved by MULTAN‐82 and refined to R = 0.067 for all 4064 reflections. There are two molecules, A and B, in the asymmetric unit with different A ring conformations. Intermolecular hydrogen bridges link the molecules into dimers.
Crystal and Molecular Structures of Modified Progestagens (IV). 17α‐Azidomethyl‐17β‐hydroxy‐estra‐4,9‐dien‐3‐one, C19H25N3O2
Authors: Reck G. , Hübner M. , Bannier G. , Scharfenberg P. 
Published: January 2007

AbstractThe crystal and molecular structure of 17α‐azidomethyl‐17β‐hydroxy‐estra‐4,9‐dien‐3‐one has been determined by X‐ray structure analysis. It crystallizes in the orthorhombie space group P 212121 with cell parameters a = 9.118(1), b = 9.252(1), and c = 20.444(2) Å. The structure was solved by MULTAN‐82 and refined to R = 0.042 for 1408 observed reflections. Steroid ring and 17β‐side chain conformations are discussed in the paper. Intermolecular hydrogen bridges between hydroxyl groups and carbonyl oxygen atoms link molecules forming chains in c‐direction.
Density Studies in Polymorphic Liquid Crystal N‐ (p‐n‐Heptyloxybenzylidene) p‐n‐Pentylaniline
Authors: Rao J. V. , Rao K. R. K. , Choudary L. V. , Venkatacharyulu P. 
Published: January 2007

AbstractDensity studies in polymorphic liquid crystal, N‐(p‐n‐heptyloxybenzylidene) p‐n‐pentyl‐aniline is carried out in isotropic liquid, nematic, smectic A, smectic C, smectic B and smectic G phases. The temperature variation of density in all the mesophases confirms that isotropic liquid to nematic, nematic to smectic A, smectic C to smectic B, smectic B to smectic G transitions are of first order while smectic A to smectic C transition is of second order. The density variation across smectic C to smectic B is greater than that of any other transition. Thermal expansion coefficients are also calculated.
Growth, Structural Characteristics and Photoelectrochemical Behaviour of Tungsten Diselenide (WSe2) Single Crystals
Authors: Prasad G. , Rao N. N. , Srivastava O. N. 
Published: January 2007

AbstractStudies in regard to structural and photoelectrochemical (PEC) properties of tungsten diselenide (n‐WSe2) single crystals grown by vapour transport technique have been carried out. X‐ray diffraction (oscillation) study reveals α curious two layer lines attributable to more than one a lattice parameters coexistence of nonstoichiometric phases is thought to lead to dual α lattice parameters (3.08 Å and 2.80 Å) observed. Surface studies with optical and scanning electron microscopic techniques revealed that the crystal surfaces possess varying density of surface steps. The photoelectrochemical behaviour of n‐WSe2 electrodes examined with stepped and stepfree surfaces reveals that the steps have significant influence on the PEC behaviour. Crystals with stepfree surfaces exhibited better photoresponse as evidenced by improved photopotential (520 mV) and photocurrent density (7.5 mA/cm2). Moreover, the improved photoresponse of n‐WSe2 crystal electrodes in the present study, as compared to the previous investigation, is expected to arise from the existence of different structural phases in the as‐grown crystals (dual phases) which can lead to tandemization effect with consequent improvement in photoresponse.
Crystal and Molecular Structure of 3‐Methoxy‐estra‐1,3,5(10)‐trien‐17β‐ol
Authors: Reck Günter , Schubert Gerd , Bannier Gloria 
Published: January 2007

AbstractThe crystal structure determination of the title compound was undertaken to determine the conformational flexibility of the steroid skeleton. 3‐Methoxy‐estra‐1,3,5(10)‐trien‐17β‐ol (C19H26O2) crystallizes in the space group P212121 with Z = 12, a = 12.589(2), b = 16.274(5), and c = 23.535(6) Å. The structure was solved by direct methods and refined to R = 0.056. Three symmetry independent molecules having different molecular conformations were observed in the crystal. The most flexible region of the molecules is the B ring which adopts following conformations: 7α,8β‐half‐chair, 8β‐sofa, and an intermediate form between half‐chair and sofa.
Electronic Structure of [Cu(C7H4NO3S)2(H2O)4] · 2H2O Crystal
Authors: Jianmin Li , Guoqiang Pan 
Published: January 2007

AbstractThe electronic absorption spectrum and ESR spectrum of the crystal of the title compound [Cu(C7H4NO3S)2(H2O)4] · 2 H2O, are measured. The experimental results are discussed quantitatively by using the ligand field theory and the radial wave function of non‐free Cu(II). The electronic structure of the compound is in agreement with its crystal structure.
Effect of Buoyancy‐driven Convection on Lamellar Spacing of an AlZn Eutectic
Authors: Tuček V. , Holeček S. , Kubiček L. , Barta Č. 
Published: January 2007

AbstractThe influence of buoyancy‐driven convection on the lamellar spacing of an Al–Zn eutectic was studied under conditions of oriented crystallization. The convection due to buoyancy was affected by the mold position respective to the direction of action of the force of gravity. It has been found that the buoyancy‐driven convection does not exert any direct effect on the lamellar spacing. Rather, it only affects the rate of advance of the crystallization front. The lamellar spacing λ of the Al–Zn eutectic can be described as function of this rate of advance V by the relation

.
Vibrational Properties of LiGaO2 (II). Theoretical Model Considerations
Authors: Neumann H. 
Published: January 2007

AbstractOn the basis of the correlation method and of a simplified version of the extended Keating model with bond‐bending forces neglected sphalerite‐ and chalcopyrite‐like modes can be identified in the lattice vibration spectrum of LiGaO2. In agreement with recently published results for LiInTe2 it is found that the LiO bond is considerably weaker than the GaO bond.
Investigations of LiInSe2 Epitaxial Layers on {100}‐ and {110}‐oriented Substrates with Sphalerite Structure by Means of RHEED
Authors: Tempel A. , Schumann B. , Mitaray S. , Kühn G. 
Published: January 2007

AbstractEpitaxial LiInSe2 films were deposited by flash evaporation technique on {100}, {110} GaAs and {100} GaP. By means of geometrical considerations based on the concept of corresponding substrate and deposit planes epitaxial relationships can be predicted and compared with results from reflection high energy electron diffraction (RHEED). The epitaxial relationships are given for both rhombic (β‐NaFeO2‐type) and tetragonal (chalcopyrite‐type) LiInSe2 deposits on {100}‐ and {110}‐oriented sphalerite‐type substrates.
Liquid Phase Epitaxy of SiC in the System SiTbSiC by Temperature Gradient Zone Melting (I). Investigation of Solubilities in the System SiTbSiC
Authors: Tairov Yu. M. , Peev N. S. , Smirnova N. A. , Kalnin A. A. 
Published: January 2007

AbstractIn the paper which is divided into three parts the liquid phase epitaxy of SiC by temperature gradient zone melting with the solvent SiTb is discussed. In the first part the solubility of SiC at different initial compositions of the SiTb solvent is studied in the temperature range 2000–2500 K.
Vickers Micromechanical Indentation Studies of Barium Oxalate Dihydrate Crystals
Authors: Dharmaprakash S. M. , Rao P. Mohan 
Published: January 2007

AbstractVickers microhardness measurements have been carried out on gel grown single crystals of barium oxalate dihydrate. The dependence of hardness on indentation load has been described. Attempts have also been made to understand the cracks developed around the micro indentation. The material chipping off and median vents observed around indentation figures have been discussed. Also explained are the fracture at high indentation load. The average load independent hardness value is 58.27 kg · mm2.
The influence of sodium chloride on the driving force of the crystallization of potassium chloride from aqueous solutions at 25 °C
Authors: König Ax. , Emons H.‐H. , Nývlt J. 
Published: January 2007

AbstractAdmixtures at higher concentrations affect the growth rate in two kinds by changing the kinetic phenomena and also the driving force. Based on measurements of the osmotic coefficient as a function of the total ionic strength of the solution at 25 °C different kinds of driving force are calculated. Usefull for the discussion of the admixture problem is the mean molal free enthalpy of crystallization. NaCl increases the driving force of the crystallization of KCl. It shows that the reason for the decreasing effect of NaCl in growth rate is a kinetic one.
Precipitation studies in an air‐slug crystallizer: Potash alum from aqueous solution using 2‐propanol
Authors: Halasz S. , Mullin J. W. 
Published: January 2007

AbstractAn air‐slug crystallizer is described and its utility demonstrated with the precipitation of potash alum from aqueous solution using 2‐propanol as the water‐miscible precipitant. Basic equipment dimensions are specified and several modes of operation explored. Best results are obtained with a controlled step‐wise addition of alcohol.
Bulk modulus — volume — ionicity relationship in tetrahedrally bonded semiconductors
Authors: Neumann H. 
Published: January 2007

AbstractIt is shown that the bulk modulus of all diamond, zincblende and wurtzite structure compounds can be evaluated by means of the simple relation B = b0a−m(1 – g0fi) where a is the lattice parameter, fi the spectroscopically defined bond ionicity and b0, m and g0 are constants having the same values for all compounds. This bulk modulus relation is used to estimate the bulk moduli for those zincblende and wurtzite structure compounds for which no experimental measurements have been made until now.
Observation of concentration boundary layers around growing or dissolving KH2PO4 crystals in stagnant solutions
Authors: van Enckevort W. J. P. , Matuchová M. 
Published: January 2007

AbstractThe solute concentration profiles around KH2PO4 crystals growing or dissoloving in stagnant aqueous solutions were studied by the schlieren method after Toepler. By this technique the thicknesses of concentration boundary layers around the crystals, formed by free convection of solution, were measured in dependence of crystal size and super (under) saturation. In the case of dissolution, theoretical estimation of the boundary layer thickness yielded a fair agreement with the observed value. For growth, the process is dominantly limited by surface kinetics, whereas volume diffusion plays a minor role.
Heat capacity of LiInS2, LiInSe2 and LiInTe2 between 200 and 550 K
Authors: Kühn G. , Pirl E. , Neumann H. , Nowak E. 
Published: January 2007

AbstractThe molar heat capacity at constant pressure of LiInS2, LiInSe2 and LiInTe2 was measured in the temperature range from about 200 K to 550 K. An analysis of the experimental data showed that the anharmonic contribution to the heat capacity can be described by a polynomial of fourth order in the temperature. A comparison of the results for the LiInC2VI compounds with those for the AgBIIIC2VI and AIIBIVC2V chalcopyrite compounds showed that the lattice anharmonicity effects are essentially influenced by the specific nature of the LiCVI bond.
Preparation and phase characterization of the SrCl2EuCl2 and SrCl2EuCl3 systems
Authors: Olejak‐Chodan M. , Hodorowicz S. A. , Eick H. A. 
Published: January 2007

AbstractThe SrCl2EuCl2 and SrCl2EuCl3 systems were investigated over the full composition ranges by the Guinier powder X‐ray diffraction technique. In the strontium chlorideeuropium dichloride system the solubility from the both ends of reactants was found when fast cooling of the melt was used. In the strontium chloride‐europium trichloride system a solid solution for the composition region up to 20 mol per cent of EuCl3 and two new intermediate chlorides, Sr4EuCl11 and Sr9Eu5Cl33, were observed. The compounds crystallize in orthorhombic symmetry with lattice parameters of 7.220(2), 35.15(1), 6.790(4) and hexagonal 12.854(4) and 24.702(8), respectively.
Influence of temperature conditions in horizontal Bridgman furnace on crystal growth of GaAs
Authors: Moravec F. , Štěpánek B. 
Published: January 2007

AbstractThe experimental investigation of the boat shape and boat position in the furnace in the case of unseeded horizontal Bridgman growth of GaAs single crystals was carried out. The relation between axial and radial temperature gradients in the furnace was also studied. On the basis of experimental results the optimum conditions for the growth of low dislocation density GaAs single crystals were derived.
About the fluorine chemistry in MCVD: The mechanism of fluorine incorporation into SiO2 layers
Authors: Kirchhof J. , Unger S. , Knappe B. , Kleinert P. , Funke A. 
Published: January 2007

AbstractFluorine incorporation during the deposition of silica layers is studied under MCVD conditions using C2F3Cl3 as fluorine source. The experimental results are compared with known models of the incorporation mechanism. It is found that a gas/solid equilibrium during the consolidation step determines the final fluorine content of the layers.
On the bindings in the elements between V and Ga(I). phase from V to Fe
Authors: Schubert K. 
Published: January 2007

AbstractIn the chemical elements following V with increasing column number (homologic number n) of the periodic system the second half of the 3d shell is filled, and various incident structural and physical phenomena like the SLATER‐PAULING relation request an explanation. A coherent energetical interpretation may be given by analysing the bonding types (bindings) in the various elements and related alloy phases. The bindings are described essentially by the types and commensurabilities of electron spatial correlations b and e. The correlations obey empirical crystal chemical rules allowing to infer further bindings. The analysis interprets (1) the structures of the elements considered, (2) the occurring limitations of HUND'S rule, (3) the change of the ground state magneton number P(N) at the average homologic number n = 8.2, (4) the Invar‐decrease of P at n = 8.5, (5) the structural change at n = 8.6. The last three phenomena may be interpreted by simple geometrical commensurabilities of the d‐electron correlation to the crystal structure.
About the effective temperature of crystal surfaces
Authors: Vlasov A. D. 
Published: January 2007

AbstractTemperature dependences of self‐diffusion coefficients, scattered electron intensities, lattice parameters and atomic bond energies are considered. All curves representing the dependences are “splitted” into two linear ones: for a surface and for a volume of the crystal. This splitting can be eliminated and the lines representing the two linear dependences be matched, if a new variable Tc = nT (where n is a scale factor and Te is an effective temperature) is introduced. The value of n is shown to vary over not a wide range (from 1.6 to 8) for all the processes considered and in all cases n > 1. A possible physical sense of the effective temperature has been considered.
Thin silicon epitaxial layers on preannealed silicon substrates
Authors: Weidner G. , Kirscht F.‐G. , Richter F. , Seifert W. , Weidner M. , Glück B. , Mai M. , Kalmanné A. Vargha , Rausch H. 
Published: January 2007

AbstractMultistep‐temperature pretreatment is used to create defect denuded zones at surfaces in conjunction with bulk defects in oxygen rich substrate wafers. Using structural etching, RF–CV measurements, EBIC investigations, and gamma spectroscopy it is shown that bulk defects act as sinks for metallic impurities being fixed at an early stage of bipolar technology, already Etchable defects induced due to subsequent processing steps – e.g., emerging from bulk regions and entering denuded zones – contain less metallic impurities. 2 μm epitaxial layers deposited on such substrates with bulk defects and denuded zones reveal excellent structural and electrical properties.