bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoelectric Behaviour of Some Phases in the InSe System
Authors: Nassary M. M. , Hussein S. A. , Nagat A. T.
Published: January 2007

The differential e.m.f. of In6Se7 single crystals as a function of temperature have been measured. The electron to hole mobility ratio is determined to be μn/μp = 3.62. The effective masses of electrons and holes are 4.21 × 10−33 kg and 9.01 × 10−29 kg, respectively. The diffusion coefficient for holes and electrons as well as the diffusion length of free charge carriers have been determined.
Kinetics of Long Term Finite Melt Liquid Phase Epitaxyal Growth of GaAs and GaAlAs Layers. I. Gallium Arsenide
Authors: Minkov D. , Nedev N. K.
Published: January 2007

A model is proposed for a description of the growth kinetics of long term finite melt liquid phase epitaxy of GaAs and GaAlAs layers. The applicability region of the model is discussed. The correct liquidus, the temperature dependence of the diffusion coefficients, the precise concentration profiles of the components of the melt, and the non‐equilibrium construction of atoms in the layer are taken into account. The influence of the crystallisation reaction at the surface of the layer is considered, and different temperature regimes of the process can be treated. Temperature dependences of the Al and As diffusion coefficients in the melt are determined, based on comparison between theoretical and experimental results for the thicknesses and the concentration profile of GaAs and GaAlAs growon (etched) layers.
Infrared and Raman Spectra of ZnIn2Se4
Authors: Riede V. , Neumann H. , Schwer H. , Krämer V. , Gregora I. , Vorliček V.
Published: January 2007

Infrared reflectivity and Raman spectra of polycrystalline ZnIn2Se4 revealed a total number of seven structures due to optical vibrational modes. Based on a comparison with previous measurements on other AIIB2IIIC4VI compounds a symmetry assignment of the modes is proposed.
Analysis of Transient Crystal Size Distribution in a Continuous Sodium Chloride Crystallizer
Authors: Dey Avijit , Gupta Bhaskar Sen
Published: January 2007

This work deals with the transient analysis of crystal size distribution (CSD) in a continuous sodium chloride crystallizer. The crystallization is assumed to take place under diffusion controlled conditions and the crystal growth models reported by Sen Gupta and Dutta elsewhere have been used. Monte Carlo (MC) scheme has been employed for simulation purposes. The simulation results have been compared with the available experimental data at steady state.
Some Physicochemical Parameters of Saturated Ternary Solutions of Systems with Mixed Crystals in their Solid Phase
Authors: Dejewska B.
Published: January 2007

The measurements of density (ϱ), viscosity (η) and hydration number (nh) of saturated solutions of ternary systems KClKBrH2O, K2SO4(NH4)2SO4H2O and KNO3NH4NO3H2O with mixed crystals in the solid phase have been conducted. It has been confirmed, that the occurence of the extremes on the curves of dependence of the properties (ϱ, η, nh) on the composition of saturated solution may be the base for the supposition that beside mixed crystals the double salts have also been formed in the solid phase of a given system.
New Temperature Control Apparatus for X‐ray Experiments
Authors: Kobayashi H. , Nakamura N.
Published: January 2007

A temperature control apparatus for X‐ray experiments for organic compounds was newly designed. It is a gas furnace system equipped with a proportional integrated differential (PID) controller. In this study, a position sensitive proportional counter (PSPC) was used as a detector in order to make quick measurements. Using this apparatus, the long spacing of 1‐octadecanol was measured by the small angle X‐ray scattering (SAXS) method. The long spacings of 1‐octadecanol in the high temperature phase and the low temperature stable one were 48.7 and 41.7 Å, respectively. The result obtained was consistent with that reported. It was confirmed that the apparatus designed here operated properly for the temperature control of organic compounds in X‐ray experiments and was useful for the structural study on the phase transition of organic samples.
Crystal Structure of N‐methyl Crotananinium Iodide — A Pyrrolizidine Alkaloid
Authors: Sharma S. D. , Padmanabhan V. M. , Goswami K. N. , Gupta Vivek K.
Published: January 2007

The crystal structure of N‐methyl crotananinium iodide has been determined by X‐ray structure analysis. The compound crystallizes in the orthorhombic space group P212121 with cell parameters a = 19.37(2), b = 7.70(2), c = 13.38(2) Å. The structure has been solved by Patterson and successive Fourier methods and refined by full matrix least‐squares methods to an R‐index of 0.075. The structural features of the title compound are noted and are compared with those of similar others of such pyrrolizidine alkaloids.
Interrelations between Interionic Separation, Lattice Energy, and Plasma Energy for Alkali Halide Crystals
Authors: Reddy R. R. , Kumar M. Ravi , Rao T. V. R.
Published: January 2007

A simple empirical relationship has been established for the estimation of lattice energies for alkli halide crystals directly from the values of interionic distances. Another new relation has also been proposed between the lattice energy and plasma energy. The calculated plasma energy values are utilized in the estimation of electronic polarizability in alkali halide crystals, in order to test the applicability of the proposed relations. Good agreement is observed between the computed and literature values of electronic polarizability. The merits of the present approach is discussed.
Optical Properties of MnIn2S2Se2 Single Crystals
Authors: Neumann H. , Sobotta H. , Haeuseler H.
Published: January 2007

Optical transmittance and reflectance spectra of MnIn2S2Se2 single crystals are measured in the wavelength range from 0.5 to 30 μm. The interference method is used to determine the refractive index of the compound for wavelengths between 0.8 and 12 μm. From an analysis of the absorption spectrum it follows that the fundamental edge is due to forbidden indirect transitions between parabolic bands for the polarization E ⊥ c with a gap energy of 1.50 eV at room temperature.
Bi2Te3 Crystals Heavily Doped with Germanium Atoms
Authors: Lošt'ák P. , Novotný R. , Navrátil J. , Horák J.
Published: January 2007

Elemental Bi, Te, and Ge of 5N purity were used to prepare Bi2Te3(GeTe) single crystals with germanium content varying from 0 up to 2.3 × 1021 cm−3. The samples were characterized by reflectivity measurements in the plasma resonance frequency range and by measurements of the electrical conductivity. Germanium content in the samples was determined by means of energy dispersive analysis. The reflectivity spectra were interpreted on the basis of the Drude‐Zener theory in the aim to obtain information on the concentration of the free carriers in the samples. It was found that Ge atoms in the Be2Te3 crystal lattice behave as acceptors. A comparison of the hole concentration with the amount of germanium built into the crystal lattice revealed that only about 1/100 of the total number of Ge atoms act as acceptors. This effect is explained by two different ways of incorporation of Ge atoms into the Bi2Te3 lattice, viz: the formation of substitutional Ge'Bi defects acting as acceptors and the formation of seven‐layer‐lamellae of the TeBiTeGeTeBiTe composition, which corresponds to the structure of GeBi2Te4.
Nucleation of an MTG YBa2Cu3Oy
Authors: Grantscharova E. , Desgardin G.
Published: January 2007

The kinetics of the appearance of the superconducting 123 phase in partially melted at 1200 °C YBCO samples has been studied in the temperature range of low undercoolings from 1040 °C to 920 °C. An EDS analysis of the phases formed at different stages of the cooling of the melt has been performed and the experimental conditions for crystallization of 123 phase with finely dispersed 211 phase in it have been established. The results have been interpreted in terms of the classical theory of nucleation and they have been applied to the MTG process for formation of highly textured YBa2Cu3Oy materials.
Distribution of the gibbs activation energy for formation of a kink around the top of the growth hills of the face (001) of TGS single crystal
Authors: Bikov A. Z. , Stoichkov S. D. , Damianova S. B.
Published: January 2007

The shape of the vicinal hills of growth of the (001) face of the TGS single crystal was investigated by a laser Michelson interferometer. It was found that the distribution of the Gibbs activation energy for formation of a kink is not equivalent around the top of the hill.
Effect of the oxygen pressure during annealing on Tc and lattice parameter c of Bi‐2212 single crystals
Authors: Vlasov M. Yu. , Kaminskaya T. N. , Moshkin S. V. , Frank‐Kamenetskaya O. V. , Vyvenko O. F. , Kretser Yu. L.
Published: January 2007

The influence of oxygen partial pressure (po2 = 10−4–1.5 · 102 atm) during annealing on the Tc and lattice parameter c of Bi‐2212 single crystals has been investigated. Antibate correlation between non‐monotonous alteration of the c parameter and Tc with the increase in oxygen content has been revealed.
Influence of proton implantation on the properties of CuInSe2single crystals (I). Ion channeling study of lattice damage
Authors: Yakushev M. V. , Tomlinson R. D. , Neumann H.
Published: January 2007

The lattice damage of p‐type CuInSe2single crystals implanted with 10 keV protons in the fluence range from 2.5 · 1014to 8 · 1015cm−2was investigated using the Rutherford backscattering/channeling technique. At proton fluences up to about 2 · 1015cm−2radiation annealing of the defects is observed which is ascribed to very high defect concentrations in the unimplanted samples. At higher fluences radiation damage occurs but the concentration of radiation induced defects ramains low. There are indications that selenium interstitials or defect complexes with selenium interstitials involved are stable defects at room temperature.
On chemically vapour‐deposited Si/Ge growth in a multi‐wafer deposition process at atmospheric pressure
Authors: Kühne H. , Morgenstern Th. , Fischer A. , Kissinger G. , Krüger D.
Published: January 2007

In multi‐wafer deposition of Si/Ge thin films from silane, germane mixtures at low‐temperature epitaxy conditions not only the depletion of the silicon source but also of the germanium source along the reactor tube axis has to be counteracted in order to get homogeneous layer thickness as well as composition. Carrier gas throughput must be minimized to have a sufficient effective chemical reaction rate at low temperature. Thus it cannot be used to flatten layer growth along the susceptor. Yet the addition of a chemically reactive gas, as for instance hydrogen chloride, is suitable to ensure a nearly constant content of the layer forming source gases along the reactor tube. On the other hand hydrogen chloride may infiltrate additional contaminants leading for instance to high oxygen concentration in the deposited layer. However, oxygen soluted or precipitated changes particular features of Si/Ge behaviour for instance during the thin film growth, the following technological stress of the wafer, or the running electronic structures of microelectronic devices.
Fabrication and characterization of ZnTe/CdSe thin film solar cells
Authors: Patel N. G. , Panchal C. J. , Makhija K. K. , Patel P. G. , Patel S. S.
Published: January 2007

Thin film solar cells have been prepared and investigated by using indium‐doped n‐CdSe in conjunction with p‐ZnTe. The films are prepared on indium tin oxide (ITO) coated glass substrates by the thermal evaporation. Thin film layers have been deposited without breaking vacuum by utilizing a mask rotating system. Silver has been used as a stimulator for bringing improvement in the crystallinity and electrical behaviour of ZnTe thin films. Indium is used for obtaining the back ohmic contacts. The solar cells thus produced have been characterized by I–V‐, C–V‐, and spectral response measurements. The maximum open circuit voltage, the short circuit current density, and the efficiency are obtained as 415 mV, 11.60 mA cm−2and 1.86%, respectively under 100 mW cm−2input optical power. The diffusion potential and depletion width are found to be 1.42 eV and 21 nm, respectively.
X‐ray interferometric investigations of structural distortions in silicon crystals as a result of diffusion
Authors: Aboyan A. O. , Sarafyan M. A.
Published: January 2007

The influence of boron diffusion on the X‐ray Moiré pattern is investigated by means of X‐ray interferometry. It is shown that at low boron concentrations in silicon, the Moiré patterns indicate the non‐dislocative character of arising stresses. At higher concentrations the dislocations arise. Basing on the obtained topogram, the maximum local stress is evaluated, which at boron concentration of 2.5 · 1019 at/cm3 is 1.05 · 108 N/m2.
Floating‐zone growth of GaAs under microgravity during the D2‐mission
Authors: Cröll A. , Tegetmeier A. , Nagel G. , Benz K. W.
Published: January 2007

A Te‐doped GaAs (100) single crystal of 20 mm diameter and 20 mm length was successfully grown by the floating‐zone method during the 2nd German Spacelab mission D2. Dopant striations due to Marangoni convection as well as a reduction of the etch pit density compared to te starting material have been found. The last part of the crystal, grown with the quite high translation rate of 120 mm/h, showed no sign of unstable growth and exhibited properties similar to the parts grown with 3 and 6 mm/h.
X‐ray diffraction study of the effects of boron on occurrence of deformation faults in Ni3Al alloy
Authors: Bhikshamaiah G. , Rao P. V. Mohan , Suryanarayana S. V. , Naidu S. V. Nagender
Published: January 2007

Ni3Al and Ni3Al alloys containing varying amounts of boron in L12 phase were prepared. All the samples were suitably annealed and then cold‐worked by hand filing. X‐ray diffraction data are collected on annealed and cold‐worked samples. The deformation fault probabilities have been evaluated by two methods, viz. peak shift analysis of powder pattern X‐ray reflections of annealed and cold‐worked samples, and lattice parameter change between annealed and corresponding cold‐worked samples. The values obtained by both the methods are in reasonable agreement. It has been found that the deformation fault probability of Ni3Al and Ni3Al containing boron alloys are very high compared to Ag and Cu base alloys. Further the deformation fault probability of Ni3Al is more sensitive to boron addition. It has been found that at least 1.22 at. % of boron goes into the Ni3Al lattice.
A study of a fast ionic conductor–Ag1−xCuxI
Authors: Nalini B. , Selvasekarapandian S. , Jayashree J. , Hariharan K.
Published: January 2007

The Conductivity of AgI–CuI system has been studied. Two molar ratios of the system Ag1–xCuxI with x = 0.05 and 0.15 have been taken. The transition temperatures are observed with conductivity measurements.
The crystal and molecular structure of three homologue 1,4‐terephthalylidene‐bis‐N‐(4′‐alkylanilines) (TBAA‐n)
Authors: Thyen W. , Zugenmaier P.
Published: January 2007

The three homologue compounds with the general formula

(TBAA‐n) crystallize in the following space groups: TBAA‐0: monoclinic, P 21 c. a = 7.656(3), b = 6.073(1), c = 16.403(7) Å, β = 91.60(2)°; TBAA‐1: monoclinic, P 21 c. a = 7.656(3), b = 6.073(1), c = 16.403(7) Å, β = 91.60(2)°; TBAA‐1: monoklin, P 21/n, a = 6.0426(11), b = 7.84171(4), c = 18.2147(31) Å, β = 92.32(1)°; TBAA‐2: orthorhombic, P ben, a = 20.9390(8), b = 14.8876(7), c = 6.2069(1) Å. The structures have been solved by direct methods and refined to R = 0.029, 0.044, and 0.049, respectively.

Despite the different conformation of the terminal phenyl rings relative to the central core of the coplanar azomethine groups and the phenyl ring, the molecular packing of the three compounds obeys the same principles in forming the crystal structure.
A stratified Monte Carlo simulation of CSD in a continuous crystallizer for size‐dependent growth
Authors: Dey Avijit , Banerjee Suman , Gupta Bhaskar Sen
Published: January 2007

This work deals with the prediction of crystal size distribution (CSD) in a continuous crystallizer for size‐dependent growth. Crystal growth rates are described by Abegg, Stevens, and Larson (ASL) model. Stratified Monte Carlo method has been employed to evaluate the integrals involved in the classical moment equation for prediction of CSD. The simulation results have been compared with the available experimental data of K2CO3 · 1.5 H2O crystals in a continuous crystall lizer.
Investigation on the equilibrium vapour pressure over a GaAs melt
Authors: Hegewald S. , Hein K. , Frank C. , John M. , Buhrig E.
Published: January 2007

Investigations of the equilibrium vapour pressure over GaAs were carried out by a Bourdon manometer in the temperature range of 1170–1260 °C. By means of this method it is possible to measure the vapour pressure in a closed system with high accuracy. At the melting point the vapour pressure is 73 ± 4 kPa over polycrystalline GaAs produced by low‐pressure synthesis and 71 ± 4 kPa over monocrystalline horizontal gradient freezing material. The experimental and the calculated values were compared.
Crystal and molecular structure of trichloro benzyl methyl carbinyl acetate (C10H9O2Cl3)
Authors: Sambyal Vinod Singh , Goswami K. N. , Singh Tej P. , Thappa R. K.
Published: January 2007

The crystal structure of trichloro benzyl methyl carbinyl acetate has been determined by X‐ray analysis. The compound crystallises in the monoclinic crystal system with the space group P21/a, with cell parameters a = 12.821(1) Å, b = 7.735(2) Å, c = 13.304(2) Å, β = 1117.15(1)°. The structure has been solved by direct methods and refined up to R = 0.064. The six membered benzene ring is planar with maximum deviation 0.0048 Å for the C(3) atom. The molecules are held together by van der Waals interactions.
Charge Transfer in analogous of TCNQ derived from fluorene with TTF
Authors: Salmerón‐Valverde A. , Robles‐Martínez J. G. , Zehe A.
Published: January 2007

In a series of three TTF‐derived dicyanofluorene charge transfer complexes, an increase of the intermolecular charge transfer has been observed for both addition of nitro groups and a suitable symmetry of the fluorene skeleton. A numerical calculus of the charge transfer was based on IR spectroscopy data with respect to the stretching absorption band of the nitrile group.
Growth and characterization of pure and doped lead hydrogen phosphate single crystals in silica gel
Authors: Manimekalai R. , Balakrishnan T. , Ramamurthi K.
Published: January 2007

Following the chemical reaction method pure and doped lead hydrogen phosphate single crystals were grown in silica gel using different gel density, various concentrations of phosphoric acid, and lead nitrate solutions. As the gel pH plays an important role in the formation of different H3PO4 species in the phosphoric acid system, the pH range in which HPO ions dominate, was considered which in turn in necessary for the growth of lead hydrogen phosphate crystals. Characteristics of these crystals were carried out by infrared spectral analysis and microhardness study.
Improvement of efficiency of ITO/Se thin film solar cells using tellurium stimulator
Authors: Patel N. G. , Lashkari B. H. , Panchal C. J. , Makhija K. K.
Published: January 2007

Indium Tin Oxide ITO/Se thin film solar cells have been fabricated by vacuum deposition. Prior to deposition of selenium film, ultrathin tellurium film has been deposited on ITO thin film. Tellurium film acts as a stimulator for bringing improvement in crystallite size, adhesion to ITO and electrical behaviour of selenium thin films. The maximum efficiency of the ITO/Se thin film solar cells without tellurium stimulator and with tellurium stimulator under illumination AM1 (100 mW cm−2) are found to be 1.68% and 2.27% while under fluorescent tubelight (0.15 mW cm−2) are found to be 5.85% and 7.05% respectively. The ITO/Se thin film solar cells exhibits high spectral response at short wavelength. The barrier height of the ITO/Se thin film solar cells was determined.
Diffusion of vacancy‐impirity‐paris in cystalline solids studied by a Monte Carlo simulation
Authors: Fritzsch B. , Zehe A.
Published: January 2007

The joint migration of vacancy‐impurity‐paris (VIPs) in dilute metallic alloys has been used in a previous publication to explain void formation resitance in electromigration experiments for certain combinations. A corresponding rule to based on the valency of matrix and alloying elements. This paper deals with the range of validity of that rule, considering thermodynamic parameters like binding and migration energy as well as temperature, which are incorporated in a Monte Carlo simulation of the migration process of VIPs. Rule exceptions are explained by the outcome of this analysis.
The influence of the melt cooling rate on the properties of YIG single crystal grown by the flux method form sintered polycrystalline maeteral
Authors: Lazarescu M. F. , Manea A. A. , Elena E.
Published: January 2007

A method for the single crystal growth of Yttrium Iron Garnet (YIG) in a PbO/PbF2/B2O3 flux mixture with a melt cooling rate of 1–2.5 °C/h is described. In order to keep constant the crystal stoichiometry as well as its specific structural and magnetic properties at such high rates of the cooling process, a previously sintered polycrystalline garnet has been used as raw material. The YIG single crystal quality was checked‐up by metallographic analysis, X‐ray diffraction, SEM, and magnetic susceptibility measurements.
Flux line pinning by defects in high Tc superconducting crystals
Authors: Boiko J. , Majewski P. , Aldinger F.
Published: January 2007

The possibility of flux pinning by different defects in the volume of high‐Tc superconductors is investigated. The elementary pinning potential, UP, and the pinning force, fP, of point defects (vacancies), one dimensional defects (dislocations), two‐dimensional defects (twin and low angle boundaries) and three dimensional defects (pores, precipitates, etc.) are estimated. The effectivity of the different defects acting as pinning centres is examined.
The estimation of crystallization kinetics from linear in n(L) versus L steady‐state data including growth rate dispersion
Authors: Mydlarz J.
Published: January 2007

A discussion of modelling of nucleation and crystal growth kinetics is presented for those mixedsuspension, mixed product removal (MSMPR) crystallizer data available in the literature, for which log population density data appears to be a linear function of crystal size. The modelling crystallization kinetics is done twice – once assuming that the system is obeying McCabe's Δ law, and again when the crystals exhibit growth rate dispersion (GRD). In the latter case the gamma, inverse gamma, log‐normal, beta, Fisher, sum of two gammas, sum of two inverse gammas, sum of two log‐normal, and sum of two constant rates of growth rate dispersion models are used for crystal growth rate estimation. Finally, McCabe's and GRD predictions are compared with the size‐dependent growth rate estimations.
Analysis of the diametral response of a czochralski crystal (I) the diameter‐melt temperature relation
Authors: Sveshtarov P. , Gospodinov M.
Published: January 2007

The paper is the first in a series which presents results on the small‐signal diametral response of a Czochralski crystal grown in a resistance furnace to variations in the heating temperature and pulling rate. It is shown that the small‐signal diameter variation is related to the small‐signal bulk melt temperature and pulling rate variation via a second order linear differential equation.
Temperature dependence of electrical conductivity and hall effect of Ga2Se3 single crystal
Authors: Belal A. E. , El‐shaikh H. A. , Ashraf I. A.
Published: January 2007

Electrical conductivity (σ) and Hall coefficient (RH) of single crystal grown from the melt have been investigated over the temperature range from 398 K to 673 K. Our investigation showed that our samples are p‐type conducting. The dependence of Hall mobility an charge carrier concentration on temperature were presented graphically. The forbidden energy gap was calculated and found to be 1.79 eV. The ionization energy of impurity level equals 0.32 eV approximately. At 398 K the mobility equals to 8670 cm2 V−1 s−1 and could described by the law μ = aTn (n = 1.6) in the low temperature range. In the high temperature range, adopting the law μ = bT–m (as m = 1.67), the mobility decreases. This result indicates that in the low temperature range the dominant effect is scattering by ionized impurity atoms, whereas in the high temperature range the major role is played by electron scattering on lattice vibrations (phonons). At 398 K the concentration of free carriers showed a value of about 1.98 × 107 cm−3.
Thin film n‐CdS/p‐AgInTe2 heterojunction
Authors: Patel Basumati H.
Published: January 2007

The fabrication and characteristics of n‐CdS/p‐AgInTe2 heterojunction is described. The height of the barrier is measured using current‐voltage characteristics and capacitance‐voltage characteristic. A barrier height of 0.85 volt is obtained. The light and dark current‐voltage characteristics and cell parameters are reported for a thin film n‐CdS/p‐AgInTe2 heterojunction device.
On the existence of a pyrochlore‐type phase in the system Bi2O3–TiO2
Authors: Kahlenberg V. , Böhm Prof.Dr.H.
Published: January 2007

The existence of a bismuth titanate in the range between Bi2Ti4O11 (Bi2O3 · 4 TiO2) and Bi4Ti3O12 (2 Bi2O3 3TiO2) has been investigated by X‐ray diffraction of samples prepared by solid state reactions. For reaction temperatures above 1100 °C and a starting composition Bi2O3 · 2 TiO2 there appeared additional lines which could be attributed to a cubic face‐centred cell with a = 10.354 Å. A multiphase Rietveld analysis based on X‐ray powder diffraction data confirmed the structural model of a pyrochlore for this compound. There is evidence that this phase belongs to the group of defect pyrochlores with a Bi3+‐deficiency resulting in a composition of Bi1.833Ti2O6.75.
Crystal Growth of Lanthanum Beryllium Hexaaluminate LaBeAl11O19 and Fields of Crystallization in the System La2O3–BeO–Al2O3
Authors: Alimpiev Alexandr I. , Gulev Valeri S. , Mokruchniko Pavel W.
Published: January 2007

The fields of crystallization in the system La2O3–BeO–Al2O3 are investigated. Single crystals of LaBeAl11O19 were grown by the Czochralski technique.
Oxygen‐Tantalum Interaction in Niobium
Authors: Pozdeev‐Freeman Yu. L. , Naboka M. N. , Starikov V. V.
Published: January 2007

This article deals with results of the investigation of oxygen dissolution in niobium foil containing tantalum impurity. Experimental data show spatial separation of oxygen and tantalum in niobium if the oxygen concentration is near to the oxygen solibility limit in niobium at room temperature. Tantalum atoms move to the foil surface, and there is more oxygen in the foil volume than near the foil surface. Enrichment of niobium foil surface by tantalum influences strongly the oxygen diffusion across the foil and foil surface ability to electron injection.
Double Salt Formation in the Cu(HCOO)2–Sr(HCOO)2–H2O System
Authors: Vassileva Violeta
Published: January 2007

The solubility in the Cu(HCOO)2–Sr(HCOO)2–H2O system has been studied by the method of physico‐chemical analysis at 25 and 50 °C. It has been established that two double salts are formed in the system: CuSr2(HCOO)6 · H2O at 25 °C and CuSr(HCOO)4 · 4 H2O at 50 °C. The latter salt has not yet been described in the literature. It has been characterized by X‐ray powder diffraction and DT and TG analysis. CuSr(HCOO)4 · 4 H2O crystallizes in the triclinic system with lattice parameters a = 12.376(6) Å, b = 13.394(4) Å, c = 11.508(6) Å, α = 93.38(3)°, β = 94.01(3)°, γ = 75.04(3)°. Dehydration proceeds in two stages.
Effect of Ultraviolet Irradiation on the Ice Nucleating Ability of AgI—AgCI—CuI System
Authors: Sivanesan S. , Sagayara P.
Published: January 2007

The effect of ultraviolet radiation on the nucleating behaviour of AgI, AgCI, AgI–AgCI–CuI system in pure water has been discussed. Also the effect of irradiated AgI—AgCI—CuI samples in the presence of chlorides of sodium, potassium, and ammonium as well as sulphates of sodium, ammonium, and magnesium has been reported. The UV exposed samples of AgI and AgCI become darkened and their nucleating activity is found to be greatly reduced as the time of exposure is increased. It is found that the exposure of the AgI—AgCI—CuI samples to ultra‐violet radiation does not produce a remarkable effect in nucleation activity, except, the samples becoming dark for longer exposure timings.
Strontium‐based Mercury Cuprates with Perovskite‐like Crystal Structures
Authors: Kuz'micheva G. M. , Khlybov E. P. , Kochetkov V. N. , Palewski T. , Warchulska J. , Afanas'ieva I. N.
Published: January 2007

Conditions of synthesis, structure, and temperatures of superconducting transitions of strontium‐based mercury cuprates Hg—Sr—Me—Cu—O (Me = Ca, La, Ce, Sm, Ho) with perovskite‐like crystal structure are described. The samples belong to two homological series: HgSr2 (Ln, Ce)n–1CunO2n + 2 + δ with the Hg—O bond directed along <110> and (Hg, Cu) Sr2Lnn–1CunO2n + 2 + δ with the (Hg, Cu)—O bond directed along <100>. The variation of composition leads to rotation of the Hg—O bond along the hk0 direction and consequently to the increase of Tc from 28 K to 81 K. An anomaly of the resistivity was observed around 200 K for most of the investigated samples, independent of their content and phase composition.
Elastic Properties of the Triclinic Pseudo‐Trigonal Room‐Temperature Phase of KIO3
Authors: Haussühl S. , Jyang Wang , Mengkai LÜ
Published: January 2007

Weakly twinned triclinic crystals of the room temperature γ‐phase of KIO3, grown from aqueous solutions, exhibit a quasi‐trigonal behaviour of point symmetry group 3m in respect to thermal expansion, piezoelectric effects, and elastic properties. The elastic tensor and its temperature derivative were determined from ultrasonic resonance frequencies of thick plane‐parallel plates and their shift upon variation of temperature, respectively. The static piezoelectric constants d222 and d211 are about fifty times larger than d111 of α‐quartz resulting in strong piezoelectric coupling coefficients of elastic waves (k1 = 0.42; k66 = 0.60). Approaching the γ‐β transition at 345.6 K from lower temperatures, the shear stiffness cE66 shows a drastic softening. The transition appears to be of second‐order ferroelastic.
Kinetics of Mixed Crystal K2(SO4, CrO4) Growth from Aqueous Solution
Authors: Kasatkin I. A. , Glikin A. E. , Bradaczek H. , Franke W.
Published: January 2007

The investigation of crystal growth kinetics and phase equilibria in the system K2SO4–K2CrO4–H2O was carried out using the method for the determination of the saturation temperature and the growth rate by microscopic observation of the seed crystal behaviour. The kinetics of mixed crystal growth can be characterized by the expression V = 450.24σ1,6,2, where σ is the value of effective supersaturation of the solution calculated by taking into account the specific features of the phase equilibria diagram. Use of this criterion allows the control of the rate of delta crystal growth from solutions of variable composition.
Evidence that the Effective Temperature of Crystal Surfaces is of Real Nature
Authors: Vlasov A. D.
Published: January 2007

It is possible to represent some surface processes by the equations used for crystal bulk by inserting in those equations the effective temperature instead of changing a lot of bulk parameters to make the equations applicable for surfaces. The surface processes include surface diffusion, heterogeneous catalysis, low energy electron diffraction etc. The effective surface temperature may be measured by thermal expansion of the first one or two surface atomic layers of crystal lattice. In this way it can be experimentally evidenced the reality of the effective temperature. Some possible applications of it in the physical and chemical processes had been described.
Epitaxial Overgrowth of LiKSO4 on β–K2SO4 Single Crystals
Authors: López‐andrés S. , Suarez M. J. , Prieto M.
Published: January 2007

Nucleation of LiKSO4 (LKS) crystals from non‐equimolar solutions may occur epitaxially on the surface of previously nucleated β‐K2SO4 (KS) crystals. Both compounds evince a profound hexagonal substructure, and have common topological features and similar coordination schemes. Moreover, they may be related by quantitative similarities between their translation parameters and by correspondence between their bond chains along the directions of epitaxy. The planes of epitaxy are (001)KS, and (0001)LKS' and on these planes [010]KS is always parallel to [010]LKS' with a misfit of 12.19%. Another pair of directions, [110]KS and [100]LKS' showing a small angular misfit (0.18°), exhibit an even lower linear misfit (3.09%).
Polymeric AdditiveS' Effect on Crystallization of Calcium Oxalate Scales
Authors: Doherty W. O. S. , Crees O. L. , Senogles E.
Published: January 2007

Laboratory studies concerned with the effects of polymeric additives on the crystallization of calcium oxalate dihydrate and calcium oxalate monohydrate are described and the results obtained are discussed. These compounds are major components of scales formed in some Australian sugar mills. The studies involved the measurement of crystallization induction periods and rates, in the presence and absence of additives. Crystal morphologies were also examined. A range of experimental conditions were employed, from studies in pure solutions of the lattice ions to those more directly comparable with the mill operation.
Structural Properties of o‐Sulphobenzoimide in Complex Crystals
Authors: Yugeng Zhang , Yebin Wang , Heng Yu
Published: January 2007

The saccharin (o‐sulphobenzoimide) crystal is synthesized and its crystal structure has also been determined. Saccharin, as a ligand, can be coordinated with a metal ion in different modes. The variations of the saccharin molecular structure in different coordination environments are studied. As the saccharin molecule takes part as ligand or anion, its molecule structure will take some obvious changes. The factors of these changes may mostly be due to the coordination environment and hydrogen bond. The effects of different coordinated metal ion and different coordination mode are very small.
Characterization and Annealing of Wet Prepared Synthetic Hydroxyapatite Powders for High‐Purity Bioceramics
Authors: Krajewski A. , Ravaglioli A. , Celotti G. , Piancastelli A.
Published: January 2007

This study deals with the production of hydroxyapatite, in particular following the transformations that are involved when it is synthesized at the proximity (95 °C) of boiling temperature of water with or without a ripening treatment. Previous studies about the degree of crystallization showed that it increases with the temperature.

This work is furthermore concerned about the quality of the obtainable ceramic with the use of synthetic hydroxapatite prepared by precipitation from aqueous solution. In particular the higher the degree of crystallinity, the lower the presence of spurious phosphates during sintering. The main structure‐related parameters were evaluated as a function of annealing temperature, and possible interpretations given thoroughly.
Drawning‐out Crystallization
Authors: Nývlt J.
Published: January 2007

Equations for the modelling of a continuous perfectly agitated crystallizer with drowning‐out reaction are presented. Because the supersaturation of the solution is usually limited by the materials balance resulting from the technology used and the crystal growth rate is thus rather low, an agglomeration mechanism is considered in order to obtain larger particles. The results are demonstrated on an example of drawning‐out of KCl by NaCl.
The Microcrystallite Model of Liquids for Noble Gases and Other Non‐Metals
Authors: Vlasov A. D.
Published: January 2007

Some main parameters of the microcrystallite model of liquids had been estimated for liquid noble gases and other non‐metals by earlier proposed method. The obtained data are in good accordance with the results for liquid metals. Thus, the radii and, especially, the relative distances between the microcrystallites in liquid non‐metals are similar to those for liquid metals. This confirms a universal feature of the proposed microcrystallite model.
Correlation of Phase Equilibria in Systems with Double Salts
Authors: Nývlt Jaroslav
Published: January 2007

The method of expansion of the relative activity coefficients has been extended to systems with double salts formation. This use of resulting theoretical equations has been demonstrated on the systems NH4Al(SO4)2 – (NH4)2SO4 – H2O and NH4Al(SO4)2 – Al2(SO4)3 – H2O. The fit of the experimental data taken from the literature and of the calculated data is very good.
The Role of Diffusion‐induced Misfit at Epitaxial Heterointerfaces
Authors: Utke Ivo
Published: January 2007

The diffusion‐induced misfit at heterointerfaces and related defect‐structure phenomena are derived analytically. On the basis of a simple diffusion model for epitaxial combinations the resulting distributions of misfit, stress, and misfit dislocation density along the diffusion direction can be quantified. Their diffusion‐induced parameters can be expressed by relatively simple relations of material parameters (e.g. diffusion coefficients, Vegard's constants, elastic constants), which allow the quick estimation of their influence at epitaxial heterointerfaces.
Analysis of Dopant Distributions in LEC‐InP
Authors: Wei Jiang
Published: January 2007

It is often important to be able to estimate the concentration of dopant atoms incorporated into InP crystals grown from InP melt of given composition. In this paper we present a simple parameter (G) to revise the commonly used effective distribution coefficient (keff) and the Scheil equation. The results obtained for various dopants and different initial concentrations in LEC‐grown InP ingots are discussed. It is shown that the revised dopant concentration curves tally with the real distributions.
Influence of the pH‐Value on the Growth and Dissolution Rate of Potassium Chloride
Authors: Mohameed H. A. , Ulrich J.
Published: January 2007

A fluidized bed crystallizer is employed to investigate the effect of pH of the solution on the growth and dissolution rates of potassium chloride crystals. The growth rate shows a minimum value at the pH range between 7 and 10, whereas the dissolution rate shows a minimum at the range between 7 and 9. It is found in this study that the growth‐ and the dissolution rate of potassium chloride in the acidic solutions are higher than in the alkaline solutions. A mechanism is suggested to explain the growth kinetics based on the interaction between the different species found in the electrolyte solution.
Static Disorder in Hexagonal Crystal Structures of C60 at 100 K and 20 K
Authors: Ramm M. , Luger P. , Zobel D. , Duczek W. , Boeyens J. C. A.
Published: January 2007

C60 · 2C8H10 (100 K): hexagonal space group P63, a = 23.694(4), c = 10.046(2) Å, V = 4884(2) Å3, Dx = 1.903 g cm−3, Z = 6, F(000) = 2856, γ(CuKa) = 1.54178 Å, μ = 0.84 mm−1. C60 · 2C8H10 (20 K): hexagonal space group P63, a = 23.67(1), c = 10.02(1) Å, V = 4862(6) Å3, Dx = 1.912 g cm−3, Z = 6, F(000) = 2856, γ(CuKa) = 1.54178 Å, μ = 0.84 mm−1. The structures were determined by Patterson syntheses and rigid‐body refinements. The C60 molecules show two orientations with one molecular centre in common. The solvent molecules are disordered too. Static disorder could not be overcome or influenced by cooling down. A coordination number of 10 was found for the fullerene molecules.
XPS Analysis of Bridgman‐grown CuInTe2 and of its Native Oxide
Authors: Neumann H. , Mast M. , Enderlein J. , Tomlinson R. D. , Yakushev M. V.
Published: January 2007

X‐ray excited photoelectron spectroscopy is used to analyse the near‐surface properties of CuInTe2 single crystals grown by the vertical Bridgman method. It is found that keeping the crystals at room temperature in air for relatively short times is sufficient for the formation of an oxide layer which consists mainly of TeO2. No detectable amounts of copper or indium oxides could be observed.
Characterizing Plasma‐exposed In0.52Al0.48As Surface Using Photoreflectance‐, Raman‐, and Photoluminescence Spectra Method
Authors: Jiang G. C. , Kuo C. W. , Chang Y. , Juang Y. D.
Published: January 2007

We have performed Photoreflectance (PR), Raman Scattering (RS), and Photoluminescence (PL) experiments to characterize the In0.52Al0.48As surface exposed to plasma by a gas mixture of CH4/H2/Ar, PR spectra indicate that RIE (plasma) causes defects such as nonradiative recombination centers, scattering centers, and defects leading to the decrease of signal intensity, broaden line width and red shift of the transitions by increasing the rf power. In the Raman scattering study, RIE causes defects against InAs‐like and AlAs‐like LO modes vibration. As the rf power increased, the maximum of two LO modes shifts towards lower frequency and the line shape becomes increasingly asymmetric. Also, the intensity degrades gradually by disorder and point defects with increasing rf power. The PL transition energies show a red‐shift with increasing the rf power. In addition, the spectral feature broadens, and the intensity decreases with rf power higher than 200 w. The consistence of the PL, PR, and RS results indicate that these three methods can be used as sensitive probes to evaluate the near surface damage of the epilayer.
Si1‐xGex Mixed Crystals Grown by Pulling‐Down Technique with Multi‐Capillary Channels
Authors: Koh H. J. , Fukuda T.
Published: January 2007

Si1‐xGex mixed crystals with 5 at% Ge concentration have been grown by the pulling‐down technique using a crucible with multi‐capillary channels. The unique feature of the technique is that Ge solute concentration of the small molten zone is maintained constant due to the condition of no back diffusion of solute through the capillary channels, and that the diffusion‐controlled solute transport causes the effective distribution coefficient to be unity. The Ge concentration was measured by the electron probe microanalysis and observed to be homogeneous along both the longitudinal and radial directions. The two‐dimensional distribution on the whole cross section was also found to be uniform.
VLS Growth of ITO Whiskers Prepared by the Electron Shower Method
Authors: Yumoto Hisami , Onozumi Shigekazu , Kato Yoshinori , Ishihara Masatou , Kishi Kiyoshi
Published: January 2007

Indium tin oxide (ITO) whiskers were grown by VLS (vapour‐liquid‐solid) mechanism, using the electron shower method. The whiskers were grown above 200 °C, and the deposition rate was above 0.6 nm/s. The electron shower controlled the size of the whiskers, and the size was 30 nm in diameter and 600 nm in length. The whiskers grew along the substrate at t < 300 s, but grew in a direction perpendicular to the substrate at t > 300 s.

When the ITO whiskers grown along the substrate were used as NO2 gas sensor, the sensitivity was 340, and about 300 times higher than those of the whiskers grown in a direction perpendicular to the substrate and plate‐like ITO crystallites.
Preparation and Novel Coordination Structure of [Cu(sacch)2(H2O)2] · 4 H2O
Authors: Jianmin Li , Yuhong Zhou , Gentao Zhou , Quanming Wang , Qun Huang , Xintao Wu
Published: January 2007

The new complex of copper (II) and saccharin – [Cu(sacch)2(H2O)2] · 4 H2O (1) has been prepared and determined by single crystal X‐ray diffraction method. It differs from [Cu(sacch)2(H20)4] · 2 H2O (2) which was reported by HAIDER et al. (1981). The compound (1) crystallizes in the monoclinic space group P21/a with lattice parameters a = 7.326(3) Å, b = 16.308(5) Å, c = 8.379(1) Å, β = 101.09(2)°, Z = 2. Copper(II) exists in a square planar structure with a C2 axis and centrosymmetry belonging to the C2h, group.
Influence of Electromechanical Resonances of the Lead‐in Filament on Interferometric Measurements of Quadratic Electrostriction
Authors: Kloos G.
Published: January 2007

In interferometric measurements of quadratic electrostriction, anomalies in the frequency‐dependence of the recorded strain signal are sometimes observed that are probably not caused by intrinsic material behaviour. The question discussed in this article is whether electromechanical resonances of the gold filament connecting the sample to the high‐voltage supply can be the origin of this effect. The expected resonance frequencies are predicted using a simple macroscopic description that combines the telegraph equation for the clectric field strength in the filament with a constitutive equation for the electric field and mechanical dilatations.
On a Correlation between the Microcrystallite Radius and the Plasticity Factor
Authors: Vlasov A. D.
Published: January 2007

The ratio of the dimensionless radius of the microcrystallites in liquid metals and other liquids at melting point to the stated earlier plasticity factor has been estimated. A frequency distribution of this ratio for 24 substances, including some metals, liquid noble gases, and other non‐metals, seems to be normal and characterized by dispersion 16.6, mean value 54, and mean error 13.5. So it was supposed, this ratio is a constant which may be used for calculation of the microcrystallite radius. Some consequences of this statement are discussed.
The Charge‐Transfer Properties of Rare Earth Complexes
Authors: Yugeng Zhang
Published: January 2007

Two new YCu complexes and some other rare earth complexes crystals are synthesized. The results of elemental analysis, IR, GTA are corresponding to their formula. The PA spectra of all these complexes and the charge‐transfer spectra are studied. The strong conjugate π system makes the charge‐transfer spectra of rare earth complexes occur in low energy positions with strong intensity. The charge‐transfer effect is also existing in the yttrium(III) complex coordinated by some ligands with the conjugate π system.
Epitaxial Growth of α‐Mercuric Iodide
Authors: Erler Bettina , Piechotka Miroslaw , Kaldis Emanuel
Published: January 2007

Mercuric iodide has been grown for the first time heteroepitaxially on a substrate. α‐HgI2 is deposited as a single crystalline layer which is azimuthally completely oriented. The orientation of the grown layer has been confirmed with texture X‐ray diffractometry, reflection powder diffractometry and Atomic Force Microscopy.
Stereometrical X‐ray Interferometric Diffraction Topography of Crystal Imperfection
Authors: Aboyan A. O.
Published: January 2007

A method for X‐ray interferometric investigation of the deformation field of crystal imperfections by means of double and triple interferometers is proposed. It is shown experimentally that by means of double and triple interferometers it is possible to detect segregation lines, displacement lines, and the Moiré patterns of different type imperfections as well.
On the Mechanism of Metastable Phases' Formation in Electrodeposited Co‐based Films
Authors: Tochitskii T. A. , Shadrow V. G. , Nemtsevich L. V. , Boltushkin A. V.
Published: January 2007

The mechanism of the polymorphic metal and alloy structure formation, taking into consideration the influence of the film content, deposition conditions, and included hydrogen, is proposed. The mechanism allows to take into account separate processes accompanying phase transition during the change of the bath pH, film thickness, film content, and account for the experimental results, obtained for CoW, CoP crystalline and amorphous films.