bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fundamental laws of fracture region of solids
Authors: Chandra B. P. , Dubey B. N. 
Published: January 2007

AbstractThe present paper reports that the deformation is statistically symmetric even in the fracture region of solids. The major factor in the fracture region of brittle solids is the creation of new surfaces. On the basis of the creation of new surfaces, four fundamental laws are derived for the fracture region of brittle solids. These laws are: (i) New surfaces are created only after a particular strain of the crystal. (ii) For the smaller values of compressive strain, the area of newly created surfaces is directly proportional to the square of the strain. (iii) The proportionality constant between the area of the newly created surfaces and the square of strain may be termed as fracture constant. Mathematically the fracture constant is the area of newly created surface for unit compressive strain of the crystal. (iv) For larger values of the compressive strain, the logarithm of newly created surfaces is directly proportional to the strain. The experimental verification of the laws of fracture region of solids are discussed. The value of fracture constant of certain solids are estimated and their significance is discussed.
The order‐disorder transformation at supercooled melt/crystal transition region of binary melts (I) the master equation
Authors: Chistyakov Yu. D. , Baikov Yu. A. , Schneider H. G. , Ruth V. 
Published: January 2007

AbstractBinary melts crystallizing with almost perfectly ordered structures if exposed to conditions close to thermodynamic equilibrium exhibit an increasing tendency to form metastable crystals with increasing disorder when these alloys crystallize on the growth conditions of supercooling. Based on the model of a two‐phase transition zone separating a growing crystal from its non‐solid surrounding a kinetic master equation is formulated describing the kinetics of competitive atomic exchange processes within the transition region. The theory considers the case of simple cubic structure with equal particle numbers of two components that form a NaCl‐type lattice at the state of perfect order. In a subsequent paper solutions of the master equation obtained for steady‐state conditions are discussed.
Determination of the complanar geometric lattice parameters of monocrystals with high precision
Authors: Grosswig S. , Jäckel K.‐H. , Kittner R. , Dietrich B. , Schellenberger U. 
Published: January 2007

AbstractA measuring method is presented which allows to determine the complanar geometric lattice parameters (the amounts of two unit cell vectors and the angle between the both unit cell vectors) of monocrystals with high precision at one crystal point and in one measurement cycle. The efficiency of the method is demonstrated at measurements of two quartz monocrystals.
Investigations of the Thermoluminescence and EPR of mechanically activated and irradiated quartz
Authors: Boden G. , Sahre P. , Ebert I. , Hennig H.‐P. , Jedamzik J. , Prösch U. 
Published: January 2007

AbstractThermoluminescence (TL) measurements are useful for a characterization of the state of order in mechanically activated quartz after X‐ray and γ‐irradiation. As the luminescence at room temperature (RT) the TL also decreases with decreasing crystallinity of the quartz. On the contrary, the concentrations of the EPR centers in quartz (E′, oxygen defect electron (ODE)) created by mechanical activation as well as irradiation increase with decreasing crystallinity. It is shown, that the electronic defects, which cause the TL, are different from the EPR centers.
Electrical conductivity and thermoelectric power of nickel‐zinc ferrites
Authors: Satyanarayana R. , Murthy S. Ramana 
Published: January 2007

AbstractElectrical conductivity (σ) and thermoelectric power (Q) of polycrystalline nickel‐zinc ferrites of different compositions was investigated as a function of composition and temperature. The electrical conductivity in these ferrites is explained on the basis of the hopping mechanism. Plots of log (σT) versus 103/T are almost linear and show a transition near the curie temperature. The activation energy in the ferrimagnetic region is in general less than that in the paramagnetic region. The carrier concentration and mobility of charge carriers has been discussed as a function of composition and temperature.
The crystal and molecular structure of 1β‐azido‐gibberellin A1 monoetherate
Authors: Kutschabsky L. , Voigt B. , Adam G. 
Published: January 2007

AbstractThe three‐dimensional structure of 1β‐azido‐gibberellin A1 monoetherate has been established by X‐ray analysis. The compound crystallizes from acetone‐diethylether in the monoclinic space group P21 with two gibberellin and two diethylether molecules in the unit cell of dimensions a = 7.799, b = 20.745, c = 8.036 Å, β = 110.23°. The final R‐value is 0.059 for 2855 reflections.
Activation parameters of some differently prepared thermoluminophors
Authors: Balarin M. , Hübner K. 
Published: January 2007

AbstractFor some thermoluminophors (LiF, Li2B4O7, CaF2, and CaSO4) a thermoluminescence peak analysis was made in order to characterize the observed processes by their activation parameters. The resulting values for E0 and K as well as the kinetic order are given. For different sample geometry the glow curve parameters can slightly be altered but the activation parameters remain almost invariant. For LiF the whole TL curve was described by a spectrum of resolved, independent levels and corresponding peaks.
Crystal and molecular structure of L‐N‐acetylhistidinamide
Authors: Pfeiffer D. , Reck G. , Oehlke J. 
Published: January 2007

AbstractDie Titelverbindung kristallisiert in der monoklinen Raumgruppe P 21 mit 2 Formeleinheiten C8H12N4O2 in der Elementarzelle. Die Gitterkonstanten sind a = 8,529, b = 11,735, c = 4,925 Å und β = 94,61°. Die Kristallstruktur wurde mit direkten Methoden bestimmt und mit der Methode der kleinsten Quadrate bis zu einem R‐Wert von 0,033 verfeinert.
Structure sensitivity of relaxation phenomena in NaCl and KCl crystals doped with some divalent impurities (III). The role of concentration and dispersion state of the dopant ions
Authors: Suszyńska M. , Capelletti R. 
Published: January 2007

AbstractThe influence of both the concentration and dispersion state of the dopant upon the behaviour of the high‐temperature depolarization‐band was thoroughly studied for NaCl und KCl crystals doped with Eu++, Pb++, and Ni++ ions.It has been evidenced that the behaviour of this band can be better explained in frames of the Maxwell(Wagner)Sillars‐model adapted for the dislocation lines surrounded by the Cottrell‐like atmospheres than by the Müller's‐model related to the excess charge conductivity effects.
Thermotropic liquid crystalline compounds with lateral long‐chain substituents (III). Molar volumina, viscosities, optical refractive indices and order parameters of 1,4‐Bis‐[4‐n‐octyloxybenzoyloxy]‐2‐n‐alkylbenzenes
Authors: Demus D. , Hauser A. , Isenberg A. , Pohl M. , Selbmann Ch. , Weissflog W. , Wieczorek S. 
Published: January 2007

AbstractIn the substance class of the general formula magnified image densities, thermal expansion coefficients, viscosities, optical refractive indices and the order parameters of a dissolved dye were measured in the isotropic and nematic states. The results are discussed briefly.
The relative intensity of Mζ‐lines
Authors: Wendt M. , Christ B. 
Published: January 2007

AbstractElectron excited M‐emission spectra of some heavy elements (64 ≦ Z ≦ 92) were studied by means of energy dispersive X‐ray spectrometry. Large discrepancies to literature data where found for the relative intensity of the Mζ‐line which is usually the strongest of the weak M‐lines. For elements Z ≧ 71 the relative intensity is almost constant and amounts to about 5%. In case of the rare earth elements Gd and Dy higher values of about 20% were obtained which are caused by anomalous self‐absorption effects for Mα and Mβ. These are reflected, too, by unusual high relative intensities of the lines Mγ and M2  N4. The energy of the lutetium Mγ‐line was determined to be (1230.4 ± 0.3) eV.
The influence of the growth temperature on residual impurities in SSD‐GaP
Authors: Kirsten P. , Koil H. , Siegel W. 
Published: January 2007

AbstractThe increase of the growth temperature during the SSD process causes a rise of the growth rate of the GaP. Hall effect and photoluminescence measurements as well as chemical analysis were used to investigate the change of the contents of residual impurities in the GaP in dependence on the growth temperature.Carbon was detected to be the dominating shallow acceptor in the undoped p‐type SSD‐GaP. Its concentration increases clearly with raising growth temperature whereas for S and N indirectly can be concluded that their concentrations diminish. Carbon and silicon are incorporated in the GaP in part in electrically inactive form.In all samples exists beside the shallow acceptor a medium deep acceptor the concentration of which is strongly correlated to that of the carbon acceptor. The luminescencespectra of the p‐type samples show a typical broad band with a maximum at 1.90 eV whose origin is discussed.
Decomposition equilibrium of arsine and low pressure doping of epitaxial CVD silicon
Authors: Kokovin† G. A. , Testova N. A. , Titov A. A. , Morgenstern Th. , Kühne H. 
Published: January 2007

AbstractCalculating the composition of the decomposition equilibrium of AsH3H2 mixtures within the temperature range of epitaxial CVD‐silicon deposition shows AsH2 to be the main component for atmospheric pressure. A drop in total pressure causes As to appear as the second main component. Taking into account AsH2‐ and As particles gives rise to an incorporation of arsenic, less and less depending on total pressure with decreasing pressure. With the aid of the incorporation equation, developed in the present paper, the experimental results on the incorporation of arsenic under reduced pressure obtained by Herring, can be explained clear of contradiction.
Polytypes of the system Fe1−xS
Authors: Kuban R.‐J. 
Published: January 2007

AbstractThe structures of Fe1−xS (0 < x < 0.135) are members of a family of derivative structures in the sense of Megaw. The NiAs structure as aristotype is the simplest and most symmetrical member of this family. The other polytypes of Fe1−xS may be derived as hettotypes by lowering the symmetry. The loss of symmetry in changing from the aristotype to the hettotype may be of various kinds: small displacements of Fe and S atoms from the NiAs positions and/or Fe vacancies in some atomic planes occur. The structures of the system Fe1−xS are interpreted as OD structures consisting of OD layers. The symmetry relations of the structures of FeS and Fe7S8 are described by OD groupoid families. Polymorphism, twinning and stacking faults are explained on this basis.
The defects and spectral properties of sapphire grown by melting methods
Authors: Kulagin N. A. , Litvinov L. A. 
Published: January 2007

AbstractThe paper is devoted to the study of the spectral properties of the sapphire single crystals grown by Verneuil, Czochralski, Cyropulos, Stepanov and horizontal directed crystallization methods. Varing the methods, parameters of growth and starting material purity, one can control the concentration of electronic and hole centers in wide range and spectral properties of sapphire up to the irradiation.
Structure and Composition of Polished PbS Surfaces
Authors: Tomm Y. , Engel A. , Gaskov A. M. 
Published: January 2007

Abstract{100} surfaces, produced from sublimation grown PbS single crystals by cutting, mechanical and chemical polishing, were characterized with regard to topography, structure and chemical composition. For this purpose, some methods independent from another were used, for instance profile measuring, dislocation etching, X‐ray rocking‐curves, RHEED, Rutherford backscattering (RBS), and AES.The results allow to describe the change of structural perfection with the depth (damage depth), the concentration profile of the main components (half‐quantitatively), and the significant decreasing of contamination. Following from this study, the model of the damage layer near the surface discussed earlier for PbTe is modified slightly.
Characterization of the Intensity Distribution in a Single Laser Spot Applied to the Annealing of Ion‐Implanted Silicon
Authors: Johansen H. , Bartsch H. , Exner H. , Zscherpe G. 
Published: January 2007

AbstractBy means of the annealing events of ion‐implanted p‐type silicon in liquid phase epitaxy (implantation dose 2.5 × 1016 As+/cm2) the degree of homogeneity of a bent quartz rod diffuser for single pulses of a Q‐switched Nd‐glass laser (λ = 1.06 μm) is investigated using SEM‐EBIC, TEM and RBS. Starting from discrete distributions of EBIC signal heights in the annealing spot the specific distribution of recrystallized monocrystalline and polycrystalline regions as well as the transition between them are proved by TEM diffraction contrast studies. The perfect recrystallization for a locally optimum laser energy density as well as the rectangular shape of the carrier concentration profile are proved by RBS measurements. At different positions of the measuring point within the annealing area RBS, too, renders it possible to point out local inhomogeneities of the energy density distribution in the case of low‐quality beam diffusers.
Dislocation Structure of Epitaxial Ferrite‐Spinel Films
Authors: Aleksandrov L. N. , Mitlina L. A. , Vasilyev A. L. , Mikhailov V. A. 
Published: January 2007

AbstractThe dislocation structure of ferrite‐spinel films obtained on the (001) plane of magnesium oxide has been studied. For the films of Mn and MgMn ferrites there has been found the formation of a cellular dislocation structure, complex dislocation clusters, for the Li ferrite the twinning.Experimental data are compared with the predictions of the theory of relaxation of internal stresses in heteroepitaxial structures. It has been shown that in the Li → Mn → MgMn ferrite the energy at the interface of magnesium ferrite and oxide ranges from 64 to 9 mJ · m−2, the absolute magnitude of lattice mismatch at a synthesis temperature being 10.328 to 3.451 × 10−3 and the critical thickness of a continuous film 0.02–0.1 μm. The formation of three‐dimensional islets‐nuclei hinders the obtaining of pseudomorphous continuous films. The critical radius (Rcr) of a pseudomorphous islet in the same series of ferrites is 0.2–1.1 μm. For Li ferrite Rexp > Rer, for MgMn Rexp < Rer, that determines the prevailing types of defects. The process of relaxation of thermal stresses is associated with the overcoming of interaction barriers by dislocations and largely dependent on the film composition and temperature.
Preferred Growth of Antimony Single Crystals
Authors: Thakar B. B. , Shah B. S. 
Published: January 2007

AbstractSingle Crystals of antimony were grown by the Chalmer's method from the melt. The crystals were grown under different temperature gradients of 92 °C/cm, 75 °C/cm and 52 °C per cm. The growth velocities were varied from 1.5 cm/hr to 9 cm/hr. At low growth velocities antimony exhibits a preferred orientation in the range 1 cm/hr to 6 cm/hr. No effect of temperature gradient is observed. The results are compared with those of bismuth, cadmium and zinc which are contradictory to what has been observed.
The Molecular and Crystal Structure of 3β‐O‐(2′,3′ ‐O‐isoropylidene‐α‐L‐rhamnopyranosyl) — digitoxigenin
Authors: Pfeiffer D. , Reck G. , Weiland J. 
Published: January 2007

Abstract3β‐O‐(2′,3′ ‐O‐isoropylidene‐α‐L‐rhamnopyranosyl) — digitoxigenin crystallizes in the monoclinic space group P 21 with two molecules C32H48O8 per unit cell and the lattice constants a = 7.865, b = 6.470, c = 29.803 Å, β = 93.95°.The structure was solved by direct methods of phases determination and subsequently refined by least squares technique to the final R‐value 0.06. The position of the lactone ring is disordered in the crystal.
A Comparative Study of Existing Polytype Notations with Reference to the CdI2 Polytypes
Authors: Wahab M. A. , Kant Rajni 
Published: January 2007

AbstractExisting polytype notations have been critically examined to select a single notation which can describe the CdI2 structures completely and most conveniently. A comparative study shows that the Zhdanov notation fulfils both the conditions. However, the ambiguities in the similar looking symbols is removed by employing some simple criteria proposed by Jain and Trigunayat for deciding the equivalent structures. Further, being numerical in nature this is the easiest notation to handle.
Dielectric Behaviour of the Nematic Phase of 4‐n‐Pentyloxyphenyl 4‐(3‐Bromo‐4‐n‐nonyloxybenzoyloxy)‐3‐ethyl‐benzoate (PBNEB)
Authors: Kresse H. , Worm K. , Schäfer W. , Stettin H. , Demus D. , Otowski W. 
Published: January 2007

AbstractDue to the high viscosity of 4‐n‐pentyloxyphenyl 4‐(3‐bromo‐4‐n‐nonyloxybenzoyloxy)‐3‐ethyl‐benzoate (PBNEB) the dielectric reorientation processes take place in the kHz and MHz range respectively. We observed two different relaxation ranges in the nematic phase from 10 Hz to 10 MHz if the measuring field is parallel to the director and one relaxation range for the perpendicular orientation. Dielectric measurements at 6.7 GHz demonstrate that at this frequency ϵ′∥ and ϵ′⊥ can be regarded as high‐frequency limit. The experimental values are discussed from the point of view of the Meier‐Maier theory.
Dendritic Growth of Ammonium Tartrate Single Crystals in Silica Gel
Authors: Saraf A. G. , Saraf K. B. , Wani P. A. , Bhoraskar S. V. 
Published: January 2007

AbstractDendritic growth of Ammonium tartrate single crystals in silica gel at 30 °C is reported. Main stem parallel to the ‘C’ axis is observed. Dendritic growth in initial and final stages with its surface structures are illustrated and described. Growth features are correlated to the growing conditions and reacting components.
Concentration Magnetic Phase Transitions in the (La1−xCaxMnO3 System
Authors: Pavlov V. I. , Bychkov G. L. , Bogush A. K. 
Published: January 2007

AbstractComprehensive investigations into crystal structures, electrical and magnetic properties of the (La1−xCax)MnO3 (x = 0 ÷ 0.6) solid solutions are performed. Two concentration magnetic phase transitions are found: antiferromagnetic‐ferromagnetic with x = 0.14 and ferromagnetic (Tc = 150 K) ‐ ferromagnetic (Tc = 260 K) at f = 0.2. It is shown that the first of them is due to the crystal structure O′O orthorhombic transition, the second ‐ to the increase of ferromagnetic interaction at the expense of additional interaction through conduction electrons. A diagram of the magnetic states for (La1−xCax)MnO3 at x = 0 / 0.6 is given.
1H‐NMR and IR Investigations of Phase Situation in Solid Sodium‐Tetramethylammonium Decamolybdate 3.5‐Hydrate at Low Temperatures
Authors: Hodorowicz S. A. , Hodorowicz E. K. , Lasocha W. , Sagnowski S. 
Published: January 2007

AbstractSodium‐tetramethylammonium decamolybdate 3.5‐hydrate was investigated in the range of 77 to 293 K by X‐ray diffractometric and wide‐line proton magnetic resonance and IR techniques. At low temperatures the compound undergoes transitions connected with change of reorientations of CH3, H2O and (CH3)4N+ groups.
Preparation and Electrical Resistivity of Intercalation Compounds of Graphitized Cokes with Antimony Halides
Authors: Preiss H. , Mayerhofer K. 
Published: January 2007

AbstractPreparation of intercalation compounds of a graphitized electrode coke and a synthetic graphite with SbCl5, SbCl4F, SbCl2F3 and SbF6 have been described and stages have been characterized by X‐ray diffraction technique. On applying pressure a de‐intercalation of antimon pentahalides have been found. The stability of intercalation compounds of graphitized cokes to pressure, temperature, organic solvents and aqueous HCI is lower than that of natural graphite compounds. Electrical resistivity of compacted intercalation compounds of different stages parallel and perpendicular to pressure direction decreases with increasing pressure, intercalant concentration and particle size. Intercalation increases anisotropy of electrical conductivity in graphitized coke and decreases it in synthetic graphite.
Role of Impurity Precipitates on Microhardness of KBr:Ba2+ Crystals
Authors: Reddy B. Kantha , Babu V. Hari 
Published: January 2007

AbstractMicrohardness of KBr crystals doped with various concentration of Ba2+ have been investigated in the asgrown state and after quenching from various elevated temperatures. It is observed that hardness increases with increase in impurity concentration and at high concentration the hardness starts decreasing. Microstructural investigations have showed the formation of visible precipitates at high concentrations. The heat treatment studies showed that in crystals quenched from elevated temperatures the visible precipitates dissociate and hardness increases.
Characteristics and Applications of the Precision Sample Current Microanalysis
Authors: Bitterlich M. , Mai H. 
Published: January 2007

AbstractThe Sample Current Microanalysis allows the identification of binary and quasibinary constituents with a higher precision and accuracy of the analytical results and an improved spatial resolution in comparison to conventional microanalytical techniques (Electron Probe Microanalysis, Secondary Ion Microanalysis). The paper describes the additional equipment required for the utilization of this method in Electron Probe Microanalysers and Scanning Electron Microscopes and specifies the required boundary conditions for analyses of high precision. In addition to the application for typical characterization problems an evaluation of the limits of this method is given.
Effect of the Terminal Substituents on the Smectic Layer Spacings in 4‐(trans‐4′‐n‐Alkyleyelohexyl) Benzoates
Authors: Dąbrowski R. , Przedmojski J. , Baran J. W. , Pura B. 
Published: January 2007

AbstractThe spacings of the smectic layers are compared with the lengths of molecules of p‐substituted phenyl 4‐(trans‐4′‐n‐decylcyclohexyl) benzoates. It has been found that if the NO2, CN or CHO groups are substituted in the p‐position of the phenyl, then the smectic layers consist of dimers, whereas in the presence of the NCS, COCH3, I, Cl, Br, F substituents the smectic layers reveal a monomolecular spacing.
Effect of In and Sb Vacancies on Temperature Dependence of InSb Lattice Parameter at High Temperatures
Authors: Morozov A. N. , Abaeva T. V. , Bublik V. T. 
Published: January 2007

AbstractThe temperature dependence of the thermal expansion coefficient for InSb has been determined in the range 25–515 °C by precision measurements of the lattice parameter of InSb single crystals. It is shown that beginning from 460 °C the temperature dependence of the lattice parameter for InSb single crystals grown from melts of different compositions is essentially affected by vacancies in the indium and antimony sublattices. The vacancy concentration and possible deviation of InSb from the stoichiometric composition are estimated from a relative decrease in the lattice parameter.
Effect of Impurities on the Etching of Sodium Chloride Crystals
Authors: Koziejowska A. , Sangwal K. 
Published: January 2007

AbstractThe results of a study of the effect of HgCl2, ZnCl2, PbCl2 and CaCl2 on the surface micro‐morphology and kinetics of etching of {100} planes of NaCl crystals in methanol and ethanol are described and discussed. It was found that addition of an impurity to the solvent leads to the formation of contrasting dislocation etch pits, and that the overall dissolution rate in a solvent decreases with an increase in additive concentration. In the case of HgCl2 impurity added to methanol terraced etch pits are observed, but their terracing behaviour diminishes with the increasing impurity concentration.