bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of chemical composition on dislocation structure and its change by plastic deformation of V3Si single crystals
Authors: Nghiep D. M. , Quyen N. H. , Paufler P. , Bertram M. , Kleinstück K. , Krämer U. , Martin A. San 
Published: July 2007

AbstractThe dislocation structure and its change by plastic deformation of V3Si single crystals has been studied by an etch technique. The solution hardening effect established elsewhere is interpreted in terms of the observed dependence of the dislocation density ϱ(r) and its increment with the plastic deformation on the chemical composition within the range of homogeneity.
Comments on the properties of an NH4OH‐H2O2 etch on epitaxial GaAs
Authors: Radácsi É. , Mojzes I. , Pfeifer J. 
Published: July 2007

AbstractThe etching rate of the NH4OH : H2O2 : H2O = 1:4:20 etch was determined on epitaxial GaAs films and bulk GaAs monocrystals. The etching process has a rather large scattering at the start of the process depending on the origin and properties of films. The etching rate of epitaxial layers approaches the value of 2 μm/min, characteristic of bulk crystals. Surfaces treated with the 1:4:20 etch are applicable to ohmic contacts of Gunn diodes.
Investigations on the growth kinetics of GP zones and a′R‐precipitates in Al‐Zn alloys
Authors: Fabian H.‐G. , Löffler H. , Kroggel R. , Gueffroy B. 
Published: July 2007

AbstractX‐ray small‐angle scattering (XSAS) and resistivity (R) measurements were particularly done with an Al‐Zn (15 at·,%) alloy in rather wide ranges of both the ageing time ta and ageing temperature Ta, in order to obtain information on the dependence of the growth exponent m of the l = β0tm growth law and the activation energy Eact on ta and Ta.The XSAS‐measurements yielded that within the range of the GUINIER radius rG between 1 nm and 2 nm the growth is essentially retarded (m < 0.1) and for rG > 2 nm m depends on Ta ranging from 0.15 to 0.23 with a maximum at 175°C. Reasons for these effects are discussed. The differences between the m‐values obtained by means of XSAS‐and TEM‐measurements are explained by the distinctions of the two methods applied.The Eact taken from XSAS‐ and R‐measurements show a remarkable increase with ta. At the beginning of the decomposition Eact = (0.49 ± 0.05) eV holds well explainable by the migration of quenched‐in VZn pairs, but at the end Eact = (1.05 ± 0.07) eV was found. This value was also obtained from TEM‐investigations (growth of the length). It fits well the Eact of ZnV pairs in thermal equilibrium at Ta.
Evidence of slip in calcium fluoride single crystals
Authors: Desai C. C. 
Published: July 2007

AbstractNatural single crystals of calcium fluoride have been cleaved along (111) planes and the cleavage faces have been etched in 0.2 N nitric acid solution. Etching produces rows of equally spaced etch pits running in <110>directions. One‐to‐one correspondence of glide bands has been established on the matched faces and on the three different flakes of the same crystal. This is further confirmed by studying the rosette structure produced on a (111) cleavage plane by indenting that plane itself. The active slip planes are found to be {110}. The implications are discussed.
On the reproducibility of the orientation distribution function of texture samples from pole figures (III). Relationship between the ODF f(g) and the reduced ODF f̃T(g)
Authors: Matthies S. 
Published: July 2007

AbstractThe explicit relationship between the ODF f(g) and the reduced ODF f̃T(g) is given and discussed. For the general case of fibre textures the f̃T(g) ↔ f(g) problem does not disappear, but in the special case with GA = D∞f̃T(g) is identical with f(g).
Reactivity of plasma‐treated SiO2 against CF4 and CCl4 — an ESR study
Authors: Tiller H.‐J. , Rudakoff G. 
Published: July 2007

AbstractSiO2‐surfaces treated by CF4‐r.f.‐discharge exhibit paramagnetic defects quite similar to those appearing after treatment in an Ar‐plasma. The defects react with O2 and H2O but not with CO2, CO and N2. CF4 itself reacts with the defects (even without maintaining a discharge) forming O2 and O2 resp. It has been shown by comparative experiments with CCl4 that CF4 is less reactive than CCl4 in respect to the destruction of the paramagnetic defects.
The pentagonal dodecahedral model of vitreous silica and its compatibility with diffraction experiments
Authors: Herms G. , Steil H. 
Published: July 2007

AbstractROBINSON's pentagonal dodecahedral model represents a very interesting non‐crystallographical heterogeneous description of atomic arrangement in vitreous silica. The pair function distribution of this model has been calculated and compaired with a measured pair function distribution of vitreous silica. The pentagonal dodecahedral model seems to be a little better than cristallite models but cannot bear comparison with the continuous random network model.
Glass formation and properties of chalcogenide systems (XXII) the phase diagram of the system PbSeGeSe2 and on the compound Pb2GeSe4
Authors: Feltz A. , Ludwig W. , Senf L. , Simon C. 
Published: July 2007

AbstractThe phase diagram of the system PbSeGeSe2 is studied by X‐ray analysis and DTA. Pb2GeSe4 is the only compound which is formed in the system. It melts incongruently at 590 ± 4°C. The formation of Pb2GeSe4 as a definite compound is supported by studying the phase relations in the corresponding area of the ternary system PbSeGeSeGeSe2.
Stress measurements in aluminium alloy films by the sin2 ψ method
Authors: Skladnikiwitz S. 
Published: July 2007

AbstractThe lattice parameters and the homogeneous elastic stresses in evaporated Al, AlSi and AlCu films 1 μm in thickness with, in part, a high degree of fibre texture have been determined. The stresses measured at room temperature as a function of the substrate temperature can be explained by the difference in the coefficients of thermal expansion between film and substrate in connection with creep processes. The different lattice parameters of the films as compared with bulk aluminium were found to be due to homogeneous elastic stresses and alloying elements.
Modelation of the state of inelastic deformation induced by a rigid indenter in a brittle material
Authors: Loges F. 
Published: July 2007

AbstractIn microhardness measurements an irreversible deformation field is produced within a sample in a region beneath the indenter. For macroscopically brittle material this can be modelled on the basis of the concept of a generalised linear‐elastic continuum theory. In discussing the results of structurally conditioned basic processes particulary the case of pressure‐induced densification is treated.
Orientation dependence of electrical and optical properties of ZnSiP2 crystals grown from melt
Authors: Siegel W. , Kühnel G. , Ziegler E. , Kirsten P. , Schneider H. A. 
Published: July 2007

AbstractUndoped and Ga‐doped ZnSiP2 crystals grown by spontaneous crystallization from nonstoichiometric melt show a pronounced dependence of electrical properties (conductivity, carrier concentration) and cathodoluminescence on the orientation of various crystal faces. Breakdown voltage measurements and Hall measurements yielded that the (112)B face is always low‐resistivity n‐type and the (112)A face is always semi‐insulating. The spectral position of the broad luminescence band observed at 80 K differs in a characteristical manner for the various crystal faces. The luminescence behaviour correlates partly with the electrical properties. The results are explained by an orientation dependence of the impurity incorporation which is reflected also in the bulk properties of the crystals.
Influence of Bi1−xSbx and Sb overlayers on the annealing behaviour of Ag films
Authors: Gloede Ch. , Müller H. , Kaiser N. , Trapp M. 
Published: July 2007

AbstractAnnealing of thin Ag films covered by Bi1−xSbx (x = 0.09) and Sb overlayers, respectively, has been investigated by measuring the electrical resistance. Material exchange by diffusion leading to the formation of an intermetallic phase between Ag and Sb was found to be mainly responsible for the annealing effects. By X‐ray and electron diffraction the intermetallic compound has been identified as the ε‐phase Ag3Sb. The diffusion processes due to annealing were studied by SIMS. A correlation between the measured resistance and electron micrographs of the cross‐sectional film structure was found.
Structural and electrical properties of CdS thin films evaporated onto GaAs substrates
Authors: Schumann B. , Kühn G. , Tempel A. , Neumann H. , Müller A. , Leonhardt G. 
Published: July 2007

AbstractCdS thin films on GaAs substrates are prepared by single source thermal evaporation under high vacuum conditions. Films on (111)A‐oriented substrates have the wurtzite structure, whereas in the case of (111)B‐oriented substrates the sphalerite structure predominates. Depositing films on pre‐annealed substrates a tetragonal phase with a composition near CdGa2S4 was found. The electron concentration in the CdS films is influenced by the substrate temperature, the growth rate of the films, and the substrate orientation.
Distinction between topography of prism faces of natural and cultured quartz crystals
Authors: Joshi M. S. , Kotru P. N. , Vagh A. S. 
Published: July 2007

AbstractResults of detailed microtopographical studies on prism faces of a large number of natural and hydrothermally grown quartz crystals are described, illustrated and discussed. In the light of these results distinction between prism faces of the two varieties of quartz is assessed. Horizontal striations, parallelogram shaped and low angle tetrahedral growth pyramids are reported as characteristic features on prism faces of natural quartz crystals, whereas hexagonal and square shaped pyramids are shown to be characteristic features on prism faces of cultured quartz crystals. Evidence of independent growth on prism faces of both the varieties of quartz crystals are given. A wide variety of growth forms, like oriented snail shaped hillocks, pentagonal elevations, rectangular spiral patterns, screw ledges, missile‐like structures, influence of impurities on advancing growth fronts, microdiscs patterns and etch patterns due to chemical etching are explained.
Microtopographical studies of ‘a’‐faces of natural analcite crystals
Authors: Joshi M. S. , Rao P. Mohan , Antony A. V. 
Published: July 2007

AbstractVertical striation, isolated elliptical natural etch pits, natural etch grooves, flat‐bottomed natural etch pits on ‘a’‐(prism) faces of natural analcite crystals are illustrated and described. Freshly exposed surfaces due to general dissolution of these faces are reported. Isolated, well defined eccentric rhombus shaped natural etch pits are illustrated and, it is established that they are nucleated at sites of emergence of inclined dislocations on the face. Rows of tiny rhombus shaped etch pits along horizontal lines perpendicular to c‐axis are illustrated and explained.
Determination of the kinetic parameters of crystal growth rate with reference to the state of mixing of the solid phase
Authors: Winter B. , Gramlich K. 
Published: July 2007

AbstractThe crystal growth rate is investigated taking into account the state of mixing of the solid phase. Micro‐mixing of the solid phase in the crystallizer is described by means of the model of complete segregation in conjunction in with the vessel model. The experiments were carried out in a laboratory crystallizer and the residence time distribution and the increase in mass of the solid phase were measured. The data obtained show that the model of complete segregation is suitable for the description of the behaviour of the solid phase flow.
Temperature dependence of doping element incorporation with the chemical vapour deposition epitaxial silicon (VI) SiH4HClPH3H2 system
Authors: Kühne H. , Sperling R. , Morgenstern Th. 
Published: July 2007

AbstractFrom comparing the incorporation behaviour of phosphorus in epitaxial silicon layers deposited from chlorosilane or silane‐hydrogen‐mixtures, it is theoretically concluded that silane hydrogen chloride‐mixtures should behave like chlorosilane mixtures and different hydrogen chloride partial pressures do not influence the dependence of the incorporation of phosphorus on temperature. The theoretical expectation had been confirmed by experiments. For very low layer growth rates, however, there is a partial pressure range of hydrogen chloride, where the temperature dependence of the incorporation of phosphorus increases with rising partial pressure of hydrogen chloride.
Mechanoluminescence and acoustical emission
Authors: Sodomka L. , Leistner M. , Tessmar H. , Karel F. 
Published: July 2007

AbstractIt is reported on the measuring of the synchronic mechanoluminescent (ML) and acoustical emission (AE). The source of both ML and AE was the mechanical deformation of organic glass, of steel and copper plates. The results confirmed the connection between MA and AE stimulated by the same deformation source.
Growth of different habits of lead bromide crystals in silica gel by the new gel technique
Authors: Abdulkhadar M. , Ittyachan M. A. 
Published: July 2007

AbstractLead bromide crystals of high optical perfection and of different habits have been grown in silica gel by new gel technique starting from colloidal lead tartrate and KBr solution. pH is found to be not a factor for habit modification. Certain habits of the grown crystals exhibit interesting surface features. The growth conditions have been optimized and the various aspects of the growth process have been widely investigated.
Growth of calcium iodate crystals by Gel method
Authors: Joshi M. S. , Trivedi S. G. 
Published: July 2007

AbstractSynthesis of single crystals of calcium iodate by gel method is described. Fairly transparent crystals of reasonably large size with different habits obtained here are illustrated. Crystals grown are identified and characterized by electron microprobe, chemical, X‐ray, thermogravimetric and infra‐red analysis.
Proximity between reacting partners for diffusion‐controlled growth of barium tungstate crystals from sodium tungstate melts
Authors: Roy B. N. , Goh Kim Hong 
Published: July 2007

AbstractThe separation distance (d12) between a diffusing particle and its host necessary for a successful diffusion was estimated for diffusion‐controlled crystal growth of BaWO4 from Na2WO4 melts. Such distances slightly increased with increased cooling rates (RT) and crystallization temperatures (T0). The energy (E), enthalpy (ΔHa), entropy (ΔSa) and free‐energy (ΔGa) of activation, and the probability factor (P) were also estimated. These parameters did not change with the changes in RT and T0.
X‐ray investigations of friction stressed α‐Fe single crystals
Authors: Puff M. , Wuttke W. 
Published: July 2007

AbstractA translation of a α‐Fe single crystal on a glass plate causes elastic and plastic deformations in regions near the surface. The dislocation density caused by the deformations and its dependence on the friction way were determined from Rocking curves. After having reached a certain friction way the monocrystalline surface layer changes into a polycrystalline layer. At the same time a friction texture develops within the polycrystalline layer.
Epitaxial AlGaAsSbGaSb (AlGaSb) heterostructures for injection lasers
Authors: Aarik J. A. , Dolginov L. M. , Druzhinina L. V. , Eliseev P. G. , Lǒuk P. A. , Milvidskij M. G. , Sverdlov B. N. , Friedenthal J. K. 
Published: July 2007

AbstractA possibility is shown of obtaining nearly perfect heterojunctions in the GaAlAsSb—GaAlSb system which do not contain any remarkable density of lattice mismatch defects at the heteroboundaries. Application to low threshold DH injection lasers for 1.4–1.8 μm spectral region for optical communications, moist‐o‐graphs etc.
On the reproducibility of the orientation distribution function of texture samples from pole figures (V). Discussion of the reprojection relationship
Authors: Matthies S. 
Published: July 2007

AbstractThe exact solution of the problem \documentclass{article}\pagestyle{empty}\begin{document}$ \tilde P_{hi} (y) \to \tilde f(g) $\end{document} is discussed from the view of the structure of the reprojection relationship and its numerical realization.
X‐ray determination of mean square amplitudes of lattice oscillations in compounds with ZnS structure
Authors: Deus P. , Schneider H. A. , Voland U. 
Published: July 2007

AbstractA general method of determination of the mean square amplitudes of lattice oscillations (MSA) for crystals with sphalerite structure is described and applied to InP. The linearity of suitable functions of the measured integral BRAGG intensities of sin2 θ/λ2 is used for the verification of the parameters selected for the correction of extinction and DTS. In this way the accuracy of the results is increased. The MSAs of the InP‐sublattices are evaluated. According to theoretical expectations the MSAs of the P‐sublattice are larger because of the greater contributions of optical phonons.
Contributions to the surface preparation of semiconductor materials of low hardness
Authors: Engel A. 
Published: July 2007

AbstractStarting from the general demands made upon semiconductor surfaces (measuring samples, substrates) and the critical material properties, the boundary conditions for the surface preparation of substances of low hardness are stated and technological variants for Bi1−xSbx, Pb1−xSnxTe, and PbS1−xSex are presented. The results show that almost defectfree surfaces of a high quality can be produced in a repeatable way. The depths of significant and detectable damages are determined depending on the technique in question.
Energy levels diagram of rare earth ions in crystal fields (I) cubic crystals (Oh, O, Td)
Authors: Kustov E. F. , Maketov T. K. , Surogina V. A. , Petrov V. P. 
Published: July 2007

AbstractThe diagrams of the energy of RE ions in a crystal field with cubic symmetry are calculated by using the method of reduction symmetry. The main diagrams of the ions Ce3+, Pr3+, Nd3+, Sm3+, Eu3+ are listed graphically.
Energy levels diagram of rare earth ions in crystal fields (II) tetragonal crystals (D4th, D4, C4v, D2d)
Authors: Kustov E. F. , Maketov T. K. , Surogina V. A. , Steczko G. 
Published: July 2007

AbstractUsing the reduction symmetry method and a system of invariants parameters the matrices of the energy stark levels for the ion Nd3+ (Er3+) in crystal field with the tetragonal symmetry (groups D4th, D2, D2d, C4v) are calculated, and the new method for determining the parameters of the CF are developed by using the properties of the sum of diagonal elements and the sum of the square of all the matrix elements and without the fitting procedure.
The precipitation of barium chromate powders from aqueous solution at different pHs: Nucleation, final crystal numbers and sizes
Authors: Packter A. , Alleem A. 
Published: July 2007

AbstractBarium chromate precipitations were studied from equivalent aqueous solutions of initial overall metal salt concentrations from 0.00013 to 0.010 M at ambient temperature and at pHs from 8 to 3. At pHs from 8 to 5, precipitation mainly occurred through homogeneous nucleation: the reciprocal induction periods (and nucleation rates) and the crystal numbers generally decreased with reduction of pH but the values at any effective mean metal salt concentration increased appreciably with increasing acidity. Presumably, both M++A and M++HA− species were taking part in the nucleation process. – At pHs below 5, heterogeneous nucleation predominated in most precipitations: the crystal numbers and nucleus numbers at any effective metal salt concentration increased with reduction of pH in these systems. Presumably, more active sites for heterogeneous nucleation were developed.
The dispersion of the dynamic scattering of colourless nematic liquid crystals
Authors: Wiegeleben A. , Demus D. 
Published: July 2007

AbstractUsing a photogoniometer the dispersion of the dynamic scattering process for visible light in colourless nematic liquid crystals was studied depending on sample voltage, observation angle and primary beam polarization. The results may be interpreted by means of a scattering model based on the dispersion effects of the birefringence and of the elliptical polarization.
On the theory of crystal growth from impure solution using monolayer adsorption mechanism
Authors: Dhanasekaran R. , Ramasamy P. 
Published: July 2007

AbstractAssuming the lateral interaction energy of the adsorbed molecules of solvent, solute and impurity in an adlayer of crystal‐impure solution interface, the partition function and its partial derivatives are calculated using the Bragg‐William monolayer model with empty sites. The condition for ideality and deviations from ideality in the adlayer are discussed. The effects of impurity on the generalized form of the BCF differential equation for surface diffusion is established and the crystal growth rate as a function of supersaturation is calculated from numerical intergration. The applicability of this model for crystal growth from impure solution is discussed.
The precipitation of barium‐, strontium‐ and calcium molybdates from aqueous solution: Kinetics of the crystal growth
Authors: Packter A. 
Published: July 2007

AbstractThe kinetics of precipitation of barium, strontium and calcium molybdates, from supersaturated aqueous solutions of initial solute concentrations C0 = 0.0004 to 0.003 M, C0 = 0.002 to 0.015 M and C0 = 0.1 to 0.06 M, respectively, were studied at 25° by conductivity measurements and chemical analysis. Nucleation occurred during induction periods and continuous crystal growth then took place onto the crystallites formed during the induction periods. The growth rates at any time were expressed, in terms of degree of crystallisation, by the relation

equation image
.The rate constants (kα) for the crystal growth of barium, strontium and calcium molybdates at 25° were 7700, 200, and 8.7 sec−1 M−2, respectively.
Thermal etch pits on calcite cleavages
Authors: Mehta B. J. 
Published: July 2007

AbstractThermal etch pits are observed on calcite cleavages when the latter are kept at 520°C to 560°C in atmosphere for some hours. Boundaries of the above etch pits are circular, hexagonal and rhombic and they are dependent upon the temperature of etching. Different etch pit morphology is observed in chemical etching on calcite cleavages. It is conjectured that origin of thermal etch pits are different from that of chemical etch pits.
The crystallisation of alkaline‐earth metal metasilicates from metal chloride melts: Preliminary experimental studies
Authors: Packter A. , Roy B. N. 
Published: July 2007

AbstractThe crystallisation of alcaline‐earth metal metalsilicates was studied by slow cooling of saturated solutions in the metal chloride melts at T0 = 830° to 1300°C, down to ambient temperature; cooling rates were varied from 20° to 200°C hr−1. Calcium metasilicate crystallised as β‐CaSiO3 prisms, strontium metasilicate as α‐SrSiO3 platelets and barium metasilicate as α‐BaSiO3 platelets. Final crystal lengths increased with reduction in cooling rate and with increase in initial crystallisation temperature.
The precipitation of sparingly‐soluble alkaline‐earth metal and transition metal oxalates and mixed metal oxalates from aqueous solution: Ionic equilibria, crystalline phases and precipitation mechanisms
Authors: Packter A. 
Published: July 2007

AbstractThe precipitations of alkaline‐earth metal and transition metal oxalates, from aqueous solution and from excess alkali metal oxalate solution, are surveyed: also the coprecipitations of transition metal oxalates together with alkaline‐earth metal oxalates. The ionic equilibria that influence these precipitations are examined, the crystalline precipitate phases are tabulated and precipitation mechanisms are analysed.