bluuebunny/crossref_metadata_2025 huggingface dataset:
Doping of epitaxial CVD silicon with arsenic or phosphorus (II). Non‐steady state conditions
Authors: Kühne H.
Published: January 2007

Theoretical expressions are developed suggesting how the non‐steady state dopant incorporation is influenced by the parameters of the layer deposition process. Expressions for the transient doping profile are dealt with taking into account two different mechanisms of the overall rate controlling step. The one is based on the assumption made by Reif and Dutton that the adsorption step, which is followed by a solution equilibrium, is the rate controlling step, the other is based on the idea that the dopant incorporation reaction and its backreaction, following after the adsorption of dopant particles, are controlling the overall incorporation.
Growth micromorphology of stearic acid crystals
Authors: Swamy R. S. N. , Prasad P. B. V. , Bhagavan Raju I. V. K.
Published: January 2007

Growth and micromorphology of stearic acid crystals grown by solvent evaporation method has been studied. The effect of the solvent and the rate of evaporation of the solvent on the growth micromorphology has been investigated. The formation of spherulitic growth features, rhombic platelets of B‐ and C forms having growth spirals associated with solution channels and twinned crystals involving B‐B, C‐C, and B‐C forms is observed. The complexity of the twins involving the B‐ and C forms is discussed.
Chemical dissolution of calcite cleavages in aqueous solutions of sodium hydroxide
Authors: Shah A. J. , Pandya J. R.
Published: January 2007

Optical study of isotropic and anisotropic etch rates by controlled chemical dissolution of calcite cleavage surfaces employing aqueous solution of sodium hydroxide at various etching temperatures is presented. The etch rates are found to be independent of etching time. The isotropic etch rates are found to be smaller than anisotropic etch rates, whereas Arrhenius plots yield activation energy for anisotropic dissolution greater than that for isotropic etching. It is also shown from a comparative study of chemical effect of various etchants on calctie cleavages that for a given plane shape of dislocation etch pits the activation energy is constant and independent of etching temperature and etchant concentration and that it is a characteristic of the etchant and not of the crystal.
Magnetic phase transitions in the Mn1‐xCrxSe (x ≦ 0.4) system
Authors: Galyas A. I. , Makovetskii G. I.
Published: January 2007

Neutron diffraction and magnetic investigations have been made on the Mn1‐xCrxSe (0 ≦ x ≦ 0.4) system solid solutions. Evidence is found of the appearance of magnetization in the samples with composition 0.05 ≦ x ≦ 0.4, exceeding in value that of antiferromagnet. The temperatures of magnetic transition, obtained from the magnetic measurements, do not fit the temperatures of disappearance of antiferromagnetic ordering obtained from the neutron diffraction studies. The antiferromagnetic structure with compositions 0.03 ≦ x ≦ 0.3 is analogous to the α‐MnSe structure. The results are discussed under assumption of simultaneous coexistence of phases with different type of magnetic ordering.
Growth of borax crystals by spiral mechanism
Authors: Takoo R. K.
Published: January 2007

Borax crystals grown at low supersaturation values are described. A brief report about microtopographical studies of these crystals is presented. Growth spirals observed on almost all the habit faces except those in contact with the bottom of the nucleation cell are described and discussed. It is established that all these crystals have platelet form in the initial stages of crystallization and as growth proceeds they develop and grow by spiral mechanism. The conditions under which the screw dislocations play the role in the development and growth of the crystals have been worked out.
SEM studies on hydrothermally grown VSZ‐3 and VSZ‐4 crystals
Authors: Joshi M. S. , Rao P. Mohan
Published: January 2007

Morphology and surface features of two varieties of hydrothermally grown zeolite microcrystals viz: VSZ‐3 and VSZ‐4 are studied by employing SEM. VSZ‐3 crystals have prismatic and prismatic pyramidal habits, whereas VSZ‐4 crystals are only prismatic with hexagonal cross‐section. In light of the scanning electron microscopic studies the plausible mode of nucleation and growth of these zeolite crystals are proposed.
TEM and X‐ray investigations of defect structure of PbSnTe crystal
Authors: Morawiec J. , Auleytner J. , Furmanik Z. , Jȩdrzejczak A.
Published: January 2007

The Pb0.8Sn0.2Te single crystal grown by the Bridgman technique was examined by X‐ray and TEM methods. The X‐ray reflection topography revealed that the PbSnTe crystal consisted of monocrystallinic blocks with linear dimensions of 1–5 mm separated by low angle boundaries of tilt‐twist character. “As grown” defects observed by TEM method have been identified as single perfect dislocations and dislocation pairs. A mean density of dislocations inside the crystal blocks was no more than 103 cm−2. Except “as grown” defects rows of mobile dislocations were observed. All of dislocations lines were characterized by the same type of Burgers vector, i.e. b = 1/2a〈110〉.
Kinetics of dissolution of potassium alum crystals in a flow cell in the presence of Fe++ cations
Authors: Karpiński Piotr H. , Larson Maurice A.
Published: January 2007

Dissolution rates of the {111} face of potassium alum crystals have been measured in situ in a flow cell. Dependence of the mass dissolution fluxes on the subsaturation and on the presence of Fe++ cations has been studied. No influence of these cations over the concentration range 0–165 ppm on the dissolution kinetics has been observed. In addition, the dissolution process has been found to be of a purely diffusive character.
Dielectric and electrical properties of vacuum‐deposited Didymium oxide thin films
Authors: Kumar J. Siva , Rao U. V. Subba
Published: January 2007

Dielectric and electrical properties of sandwich structures of didymium oxide thin films of several thicknesses have been investigated. The variation of capacitance and dielectric dissipation factor (Tan δ) with frequency in these films have been studied. These studies have shown that at room temperature, the capacitance increases with decrease of frequency and the variation is more pronounced at low frequencies. With increase of frequency, the dissipation factor decreases. The increase of capacitance with decrease in frequency has been attributed to the space‐charge polarisation and blocking of charge carriers at the electrodes. The effect of thickness on capacitance and Tan δ in these films have been studied. Current‐Voltage characteristics (I—V) of sandwiched Al‐didymium oxide‐Al structures have been studied at room temperature. These characteristics showed that the breakdown voltage increases and the dielectric strength decreases with increase of oxide film thickness. Conductivity (σ) at room temperature have been calculated to understand the mechanism involved in the conduction process. These results indicated that the conduction in these films is due to Schottky barriers. Breakdown patterns obtained in these structures by the application of de voltage applied across the sandwich structures have been observed with the help of Carl‐Zeiss, Jena, optical microscope. The photomicrographs of these breakdown patterns indicate that the type of breakdown in these structures may be single‐hole breakdown and is proceeded by propagating breakdown.
The properties of xPbTiO‐ (0.9 — x) PbZrO‐ 0.1 PbW0.5Cd0.5O3 solutions in the region of coexistence of tetragonal and rhombohedral phases
Authors: Kwapuliński J. , Hańderek J.
Published: January 2007

The changes of the dielectric permittivity η, dielectric loss tg δ, piezoelectric coefficient d33, pyroelectric coefficient p, remanent polarization Pr and reorientation processes of polarization in dependence on percent content of PbTiO3 in the xPbTiO3−(0.9 — x) PbZrO3− 0.1 PbW0.5Cd0.5O3 solid solutions in the phase coexistence region (PCR) wree investigated. It was pointed out that the characteristics of mentioned parameters possess singularities in this region. The values of average Curie temperature obtained from structural, dielectric and pyroelectric measurements were compared. Presented results let us connect dielectric properties of studied solid solutions with their structure.
Synthesis, crystal growth and characterization of Tl3BX4‐compounds (B = V, Nb, Ta; X = S, Se)
Authors: Wacker) K. , Buck P.
Published: January 2007

Single crystals of Tl3BX4‐compounds (B = V, Nb, Ta; X = S, Se) were grown by the Bridgman‐Stockbarger technique. The compounds were synthesized from the high‐purity elements. The melting points were determined by differential thermal analysis. Tl3VS4, Tl3TaS4and Tl3TaSe4yielded single crystals up to 10 cm3. The other compounds show single crystalline pieces up to 1 cm3. Infrared photographs and electron microprobe analyses revealed inclusions of TlS in the sulfur compounds, in Tl3VSe4and Tl3NbSe4inclusions of TlSe and in Tl3TaSe4small amounts of Ta.
Growth, X‐ray structure and optical investigations of epitaxial films of solid solutions of lithium niobate‐tantalate
Authors: Madoyan R. S. , Sarkisyan G. N. , Khachaturyan O. A.
Published: January 2007

Processes of the liquid phase epitaxy of films of solid solution of lithium niobate‐tantalate grown from the limited plane‐parallel volume of the liquid phase is considered in the paper. Morphological and structure characterstics of films are investigated. The possibility of the effective use of the obtained structures as active elements of the integrated optics is shown.
Heat and mass transfer in a gas‐transport reactor for multicomponent solid phase deposition
Authors: Barovskii N. V. , Gerzen A. T. , Dobrynin A. V. , Najda G. A.
Published: January 2007

Gas temperature distribution in an epitaxial horizontal flow reactor was measured by means of a thin thermoprobe and measurement error was calculated. For a turbulent gas flow, the thickness of an equilibrium layer was estimated, the results obtained being coincident with the boundary layer thickness determined from the relationships for gas temperature distribution in the reactor. The distribution pattern of the rates of mass‐transfer processes is discussed with reference to multicomponent solid phase deposition lengthwise the reactor. That the layer of nearly uniform composition can be deposited under turbulent flow conditions only is exemplified by the deposition of solid solutions of aluminium and gallium nitrides.
Raman scattering study of dopant homogeneity in GaP and GaAs single crystals
Authors: Irmer G. , Monecke J. , Siegel W.
Published: January 2007

Application of Raman scattering as a non‐destructive method with high spatial resolution suitable for the determination of charge carrier profiles connected with dopant segregations in polar semiconductors is reported. Single crystals of GaP and GaAs are investigated. The results are in good agreement with electrical measurements.
The order‐disorder transformation at supercooled melt/crystal transition regions of binary melts (II). The steady‐state solution
Authors: Chistyakov Yu. D. , Baikov Yu. A. , Schneider H. G. , Ruth V.
Published: January 2007

In a preceding paper a kinetic master equation has been derived describing the kinetics of atomic exchange processes that occur within the transition region separating a growing binary crystal and its nonsolid surrounding. For simple cubic structures, with the lattice sites being occupied by equal particle numbers of two components (in the case of perfect order corresponding to an NaCl‐type lattice) solutions for the steady‐state conditions have been derived. According to the solutions the long‐range order parameter is related to the atomic interaction energies, the arrival rate of particles at the crystal surface from the melt, and to temperature. A critical supercooling is predicted for the transition from a partly crdered structure to a disordered structure of the crystals growing from the melt. At the critical supercooling the temperature dependence of the crystallization rate reveals a characteristic change.
Surface morphology of iron specimens boronized with BCl3‐H2 mixtures (II) investigation of short‐time gas phase boronized iron surfaces
Authors: Ritzel B. , Bochmann G. , Wagner W. , Marx G.
Published: January 2007

Specimens made of armco iron or pure iron were boronized during a time ≦; 1 minute with 1.1 vol.% BCl3 in H2, and then their surfaces were investigated by scanning electron microscopy and X‐ray diffraction. The boride particles consist of FeB and Fe2B, they crow oriented on the substrate surface, e.g. the Fe2B (110) crystallographic plane is situated parallel to the (111) plane of α‐iron. The polycrystalline substrates are decorated by growing boride particles so that grains, twinning, etc. can be seen. There is a correlation between number per area and size of boride particles in early stages of layer formation and surface morphology in advanced layer growth.
The coprecipitation of magnesium chromium hydroxide powders from aqueous solution: Precipitate compositions and coprecipitation mechanisms
Authors: Packter A. , Panesar K. S.
Published: January 2007

Magnesium chromium (III) hydroxides were coprecipitated at ambient temperature from different mixed metal cation solutions — at CMtot = 0.1 M and Mg/Cr2 ratios varying from 1 to 4 — with sodium hydroxide solution. The coprecipitations were monitored by potentiometric (pH) titration and the final precipitate compositions were examined by chemical analysis, i.r. spectrophotometry and thermal analysis. Generally, microcrystalline chromium(III) hydroxide was first precipitated at pH about 5; this material then redissolved on further addition of hydroxyl ion to form hydroxochromate(III) anion and magnesium chromium hydroxide coprecipitates were then formed continuously (at OH/Cr ratios from 4 to 10) at pHs from 9.5–10 to about 11.

The coprecipitates from Mg/Cr2 = 1 systems was predominately magnesium hydroxochromate hydrate. The coprecipitates from Mg/Cr2 = 2 to 4 systems were mixture or solid solutions of magnesium hydroxochromate hydrate with increasing amounts of magnesium hydroxide. The ionic equilibria involved in different coprecipitations are discussed.
The determination of liquidus data in the In‐As system
Authors: Knobloch G. , Gottschalch V.
Published: January 2007

Liquidus data of the In—As system were determined in the temperature range 450–630 °C using a seed dissolution technique. The analytical estimation of the arsenic content in the melt was carried out by coulometric titration. In the investigated region, the plot of In x(1 — x) versus 1/T shows a weak concave curvature with reference to the 1/T axis.
Deformation state of 49BF‐implanted Si wafers after high‐temperature thermal annealing
Authors: Vassilev I. S. , Petrov I. N. , Botev P. A. , Furmanik Z. , Auleytner J.
Published: January 2007

The bending of 49BF‐implanted Si wafers due to high‐temperature annealing (T = 900 to 1100 °C) is investigated by means of X‐ray topographic techniques. The results are comperatively considered with those for low‐temperature annealing (T ≦ 800 °C) obtained earlier by the authors. It is shown that the most essential differences in low‐ and high‐temperature intervals occur for implantation dose below the amorphization one.
Characterization of single crystal silicon solar cells through illuminated I‐V family curves
Authors: Martell A. , Aguilera S. , Safranova N. , García M.
Published: January 2007

In this paper we analize the illuminated I‐V family curves of the single crystal n/p silicon solar cells obtained in our laboratory. It is demonstrated that through the correction of the higher slope region from the Voc vs ln Isc curve, experimental values of the diffusion current, with great repetibility, are obtained, which are in good agreement with theory. Influence of recombination current on fundamental parameters of solar cells is analized, making use of programable calculator. It is demonstrated that for A ≧ 3 this influence is negligible.
The coprecipitation of calcium aluminium hydroxide (calcium hydroxoaluminate hydrate) powders from aqueous solution with sodium hydroxide: Precipitate compositions and percipitation mechanisms
Authors: Packter A. , Khaw L. F.
Published: January 2007

Calcium aluminium hydroxides were coprecipitated from different mixed metal cation solutions — at total CM = 0.1 M and Ca/Al2 ratios from 1 to 4 — with sodium hydroxide solution at ambient temperature. The coprecipitations were monitored by potentiometric (pH) titration and the final coprecipitate compositions were examined by chemical analysis, infra‐red spectrophotometry and thermal analysis Generally, microcrystalline aluminium hydroxide was first precipitated at pH about 4; this then redissolved on further addition of sodium hydroxide to form hydroxoaluminate anion and polyanion and calcium aluminium hydroxide coprecipitates were formed continuously at pHs from about 9 to above 12. Their compositions were similar to the calcium hydroxoaluminate hydrates formed by direct precipitation from high pH sodium hydroxoaluminate solutions.

At Ca/Al2 ratio = 1, the main phase was probably Ca2(H2O)h[Al2(OH)4]2 with some Al(OH)3;

At Ca/Al2 ratio = 2, the main phase was probably Ca2(H2O)h[Al2(OH)10] dehydrating to Ca2[Al2O(OH)8];

At Ca/Al2 ratios = 3–4, the main phase was Ca2(H2O)h[Al2(OH)10] with increasing amounts of Ca4(H2O)h(OH)4[Al2(OH)10] and 5–10 percent adsorbed or post‐precipitated Ca(OH)2.
Crystal and molecular structure of 2‐(1‐[alkyl, aryl)‐2‐acylhydrazino]‐4,6‐diaryloxy‐1,3,5‐triazine, C20H19Br2N5O3
Authors: Reck G. , Bannier G. , Just M. , Goldhahn F.
Published: January 2007

Die Kristall‐ und Molekularstruktur der Titelverbindung wurde mit Hilfe der Röntgenkristallstrukturanalyse bestimmt. Sie kristallisiert in der monoklinen Raumgruppe P 21/c mit den Gitterkonstanten a = 8,760 Å, b = 26,863 Å, c = 9,678 Å und β = 106,03°. Die Struktur wurde mit der Schweratomtechnik gelöst und mit der Methode der kleinsten Quadrate bis zum R‐Wert von 0,075 verfeinert.
The coherent phase diagram of AIIIBv ternary system
Authors: Kuznetsov V. V. , Sadowski W. , Sorokin V. S.
Published: January 2007

The equations of the coherent phase diagram for AIIIBV ternary system are derived in suggestion of simple solution model. The system Ga‐As‐P is analyzed in details. The solubility of GaP and GaAs in liquid phase Ga‐P‐As of different composition has been investigated. The stabilisation effect of solid solution composition has been quantitatively described using the system Ga‐In‐P.
Energy band‐gap in elastic‐strained heteroepitaxial layers
Authors: Konnikov S. G. , Umansky V. E.
Published: January 2007

The effect of internal elastic stress on energy band‐gap shift in the A3B5 heteroepitaxial layers was investigated. The possibilities to get higher accuracy of divergent beam X‐ray stress determination method, designed in the scanning electron microscope (SEM), was presented. X‐ray topography method in the SEM with X‐ray magnification from 2 up to 10 was for the first time described.

The epilayer photoluminescence (PL) peak energy shift as a function of internal elastic stress was measured on the GaInP/GaAs, GAInAsP/InP heterostructures and the influence of different factors on the accuracy of the results was discussed.
The study of the influence of deep level defects on GaAs epilayer electrophysical parameters with electron beam and photoelectron paramagnetic resonance methods
Authors: Bagraev N. T. , Konnikov S. G. , Raitsin A. B. , Sobolev M. M.
Published: January 2007

Deep level point defects in the GaAs p+‐pˆ−nˆ structures, grown by liquid‐phase epitaxy, were investigated with electron‐beam methods (electron‐beam induced current and modulation method) and photo‐EPR. It was shown that during the growing process the donor AsGa antisite defects with levels ev + 0.52 eV and ec — 0,75 eV and acceptor defect with the level ev + 0.44 eV have appeared. The interconnection between the thickness of pˆ‐layer, the concentration of deep levels defects, diffusion length of the minority carriers in the p° and n°‐layers was found.
Anomalous thermal expansion of osmium dioxide
Authors: Venudhar Y. C. , Iyengar Leela , Krishna Rao K. V.
Published: January 2007

The precision lattice parameters of osmium dioxide have been determined at different temperatures, in the temperature range 30–444 °C, using a Unicam high temperature powder camera 19 cm in diameter and CuKα radiation. The data have been used to evaluate the coefficients of thermal expansion at various temperatures by a graphical method. The ‘a’ parameter increases non‐linearly with increasing temperature while the ‘c’ parameter remains constant throughout the range of temperature studied indicating a zero coefficient of expansion along the c‐direction. The abnormal thermal behaviour of this compound is explained in terms of the electronic configuration of the d‐shell of the cation.
Microhardness studies on some compound semiconductors
Authors: Nagabhooshanam M. , Babu V. Hari
Published: January 2007

Vickers microhardness studies on some III–V and II–VI compound semiconductors have been made. The results showed that ZnS has the highest microhardness value. These results are compared with other properties of the crystals such as melting point, ionicity etc. Variation of microhardness with load was also studied on all the crystals. The results indicated that the hardness value increases at low loads. These results have been analysed by using resistance pressure model and interpreted.
Orientation changes during recovery of compressed Mo crystals
Authors: Larikov L. , Belyakova M. , Zakharov S. , Mudruk P.
Published: January 2007

The type of the recovery variety which is accompanied by changes in texture is studied. Reorientation of the surface of compressed Mo crystal was observed during its annealing before recrystallization. As a result, new macroscopic {100} orientation areas appear on the contact crystalline surface of {111} orientation. Turned areas have a more perfect inner structure and correspondingly lesser density of deformation defects. As a result of rotation a high‐angle boundary interface occurs as a “broken boundary”. The transition layer considered is highly stressed and contains microcracks.

The boundary interface is shown to be the intensive recrystallization source, where the recrystallization grains are nucleated at the expence of interface dislocation bulgings.

The driving forces of the rotation observed and a scheme of a residual stress distribution in the compressed crystal are analysed. According to the scheme a deformed crystalline surface is affected by the compressive stresses and the inner layers are affected by the tensile ones. A relaxation of the internal stresses results from plastic rotations. A rotation moment arising between the surfaces and internal layers of the crystal leads to reorientation.
Thin film diffusion studied by high temperature electron probe microanalysis
Authors: Berndt K. , Karin H.
Published: January 2007

Diffusion in Thin Film Systems (TFS) can be studied effectively by means of Electron Probe Microanalysis (EPMA). Using a heating stage in the microprobe the diffusion process in the NiCr/Al TFS was studied by the continuous detection of the Ni‐, Cr‐ and Al‐X‐ray intensity. For the case of long diffusion times and taking into account the specific features of the depth distribution of the excited X‐rays the volume diffusion coefficient, frequency factor and activation energy for the Ni diffusion in Al were determined. Results for NiCrAl interdiffusion will be submitted.
X‐Ray photoelectron valence band spectra from semiconductors Bi2Te3 and Sb2Te3
Authors: Chassé T. , Berg U.
Published: January 2007

Angular resolved X‐ray photoelectron spectra (ARXPS) are measured for valence bands of the layer semiconductors Bi2Te3 and Sb2Te3. Starting from simple models taking into consideration the atomic construction, photoionization cross sections and the crystal structure the spectra can be interpreted. Important conclusions are drawn on the electronic structure of these semiconducting compounds.
Investigation of the surface composition changes caused by Ar+‐, N+2‐ and He+‐Ion bombardment of CuNi and AgPd alloys using auger electron spectroscopy
Authors: Heichler W. , Langhammer J. , Zwanzig W.
Published: January 2007

The selectivity of the sputtering process of CuNi and AgPd alloys with different bulk compositions during Ar+‐, N+2‐ and He+‐ion bombardment was studied by the help of Auger electron spectroscopy. It was found that for CuNi alloys a Ni‐enrichment and for AgPd alloys a Pd enrichment takes place compared with bulk composition. The selectivity of the sputtering process decreases with decreasing sputtering ion mass. This result was explained in the case of CuNi alloys on the base of the dependence of elemental sputtering coefficients on the sputtering ion mass.
Crystallization of hydrocarbon (n‐C28H58): Fatty acid (CH3(CH2)14 COOH) mixtures (III). The habit modification
Authors: Prasad P. B. V.
Published: January 2007

The role of n‐octacosane in promoting the growth of fibrous crystals of palmitic acid is studied. The study indicates that (i) adsorption is the probable interaction between the fatty acid and hydrocarbon molecules; (ii) The observed temperature dependence of occurrence of fibrous crystals warrants the adsorption to be a mixture of physisorption and chemisorption and (iii) it is the chemisorption component that is active at elevated temperatures and as a result it promotes the growth of fiber‐like crystals of the fatty acid.
Growth of bis‐dimethylglyoximate Co (III). Single crystals
Authors: Garcia‐Ruiz J. M. , Lopez Martinez C. , Martin‐Vivaldi Cabellero J. L.
Published: January 2007

Single crystals of bis‐dimethylglyoximate Co(III) up to 8 × 6 × 2 mm. in size have been grown by the first time, using diffusion method at room temperature. Optimum size and quality were obtained at pH = 6. These crystals are orange in colour and an X‐ray study shows it to be monoclinic, space group P 21/n, with a = 8.432(4), b = 14.147(3), c = 13.746 (6) and β = 103.78(3)°. The effects of different experimental devices on the growth features are discussed.
Growth and properties of calcium tungstate
Authors: Batra N. M. , Godbole R. S. , Arora S. K.
Published: January 2007

CaWO4 single crystals have been grown and compared by three different high temperature solution methods, viz. the normal flux‐cooling procedure, the indirect flux‐reaction technique and the isothermal flux‐evaporation method. The typical as‐grown bipyramidal crystals obtained by these methods have been found to be mostly large and perfect with varying degree of transparency. The crystals are characterised by using EDAX, X‐ray diffraction, electrical conduction, micromechanical tests and chemical etching. The assessment of various characteristics of the grown crystals is likely to show enormous usefulness of the flux grown crystals.
Methods for determination of effective diffusion coefficients in ternary alloys (II). Indirect methods of calculating ternary diffusion matrix
Authors: Malik M. T. , Bergner D.
Published: January 2007

We summarised, in part one of this paper, procedures of measuring diffusion matrix in three‐component single phase alloys direct from the concentration‐distribution profiles in infinite diffusion couples. In this paper (Part II) some procedures have been outlined which enable calculate ternary diffusion matrix from easily measurable tracer coefficients in ideal and non‐ideal single phase solid solutions. These procedures have been illustrated with examples, so that it becomes apparant that in many cases the experimental difficulties faced by the experimentalists in direct measurement of ternary diffusion coefficients can be reduced to a large extent.
Thermotropic Liquid Crystalline Compounds with Lateral Long Chain Substituents (VII). X‐Ray Studies in 1,4‐Bis‐(4‐n‐oetyloxybenzyoloxy)‐2‐n‐alkylbenzenes
Authors: Diele S. , Roth K. , Demus D.
Published: January 2007

X‐ray studies in substances with the general formula magnified image in the nematic states were performed. The results prove the existence of cybotactic groups despite the fact that the branched substances do not show smectogenic properties. We propose a model for the packing of the molecules, which explains the influence of the lengths of the lateral branches on the structure of the cybotactic groups.
Crystal Structure and Thermal Phase Behaviour of 2,3‐Dicyano‐4‐n‐hexyloxyphenyl‐trans‐4‐n‐heptyleyelohexanoate
Authors: Hartung H. , Baumeister U. , Jaskólski M. , Mädicke A. , Wiegeleben A.
Published: January 2007

The title compound with the formula C7H15C6H10COOC6H2(CN)2OC6H13 (DHPHC) crystallizes in the monoclinic space group P 21/n with a = 5.633(1), b = 14.254(1), c = 33.435(7) Å, β = 91.56(2)°, and four molecules per unit cell. The structure has been solved by direct methods and refined to R = 0.082.

The DHPHC molecules adopt a banana‐shaped but considerably stretched form and show a parallel arrangement of their long axes in the crystal lattice.

The phase transitions of DHPHC have been investigated by DSC and thermal microscopy. The compound shows a rather complicated melting behaviour and forms two solid phases and a monotropic smectic A phase.
EDA Complexes in Liquid Crystalline Mixed Phases of Novel Compounds with Lateral Dicyanoethenyl Substituents
Authors: Weissflog W. , Pelzi G. , Demus D.
Published: January 2007

We synthesized each four members of the new series magnified image All compounds are nematic. The dicyanoethenyl derivatives possess strong elecgtron acceptor properties. This is demonstrated by EDA complex formation in two binary systems in which induced smectic phases are lacking.
The Influence of the Purity and Thickness of Niobium Foils on its Mechanical Properties
Authors: Savitsky E. M. , Efimov Yu. V. , Galperovich D. Ja. , Korzhakova T. V. , Rjabtzev L. A. , Shapovalov Yu. P. , Brovko A. P.
Published: January 2007

The content of contaminants, microstructures, surface condition, electrical resistivity and mechanical properties of niobium foils and bands (13–1000 μm thick) after cold working (90–99.9%), surface etching and heat treatment under vacuum (0.001 Pa at 700–1200 °C for 1–5 hrs) are studied. The effect of the previous working and different environmental conditions including initial and acquired surface contamination with oxygen, carbon, nitrogen and iron increases noticeably with the rise of the working degree and decrease of the foil thickness. The mechanical properties of foils and bands (≧ 100 μm) practically don't differ from massive standard samples. At the foil thickness of ≦ 40 μm the dimensional effects and the influence of the surface layer are especially noticeably. The optimal combination of the whole complex of surface and volume properties at the minimum dimensional effects is observed on the 50 μm thick foil. The improvement of foil properties can be achieved due to etching its surface layer up to the depth not less than 4 μm (on each side) after the cold working and following annealing at 1000–1100 °C (1–3 hrs).
Physico‐Chemical Properties of Kutch Bentonite
Authors: Takoo R. K. , Patel B. R.
Published: January 2007

A report about the location and estimated amount of bentonite deposits in the Kutch district of Gujarat State, India is presented. Physioc‐chemical analysis reveals that Kutch bentonite is a sodium‐predominant variety and X‐ray diffraction data shows that it consists mainly of montmorillonite and beidellite and contains minor amounts of vermiculite. It is suggested that quality‐wise Kutch bentonite possesses all the properties equivalent to Wyoming bentonite.
Mechanism of Various Growth Morphologies of Kutch Quartz Crystals
Authors: Takoo R. K.
Published: January 2007

Locations and estimated amounts of deposits of quartz crystals found in the Kutch district of Gujarat State, India are given. A report about various morphologies of these crystals in geodes is presented. Influence of supersaturation on the mechanism of formation of the initial, intermediate and final growth morphologies has been assessed. It is suggested that the changing growth morphology is a function of supersaturation value. Trapezium‐shaped and semi‐circular hillocks observed on the prism faces are described and discussed. It is proposed that these hillocks develop and grow in a sequential manner and like crystals have initially triangular form.
DC Electroluminescence in (ZnS, ZnO): Cu, Cl Electroluminors
Authors: Bhushan S. , Diwan Deepti
Published: January 2007

Some interesting oberservations on the DC electroluminescence of (ZnS, ZnO):Cu, Cl electroluminors are reported. A burst of emission is observed at the time of switching on (also at switching off) the field which very slowly decays to a saturation value. The time for saturated emission decreases with increasing temperature. The emission colours of bursts and the saturated light are different. The intensities of the bursts are dependent upon the polarity of the electrodes and the temperature. Possible explanations to these effects are proposed.
Growth and Morphological Studies of Anhydrous Diglycine Sulfate Single Crystals
Authors: Pandya G. R. , Vyas D. D.
Published: January 2007

Diglycine sulfate single crystals are grown from aqueous solution by evaporation method. The effect of growth conditions are studied with respect to the perfection and morphology of the crystals. The seed history, growth temperature and pH of the solution are found to bear pronounced effects. The results are reported in the present paper.
Glow Curves of Thermally Pretreated KCl:Mn2+ Crystals
Authors: Sayanna R. , Reddy K. Narasimha
Published: January 2007

Thermoluminescence studies of KCl crystals doped with 0.5 mole% of Manganese both in “as grown” state and after quenching them from various elevated temperatures indicate that the position of the glow peaks is found to depend upon the state of dispersion of impurity. In quenched crystals two additional peaks one around 130 and other around 215°C are observed. Dipoles near dislocations are suggested to be responsible for 130°C peak and 215°C peak to a complex formed by the associated of one or more Mn2+ ions with a single vacancy or an aggregate of vacancies, the complex being situation in the dislocation region.
Crystallisation Mechanism in Gradient Temperature Zone Melting
Authors: Peev N. S.
Published: January 2007

Theory of zone recrystallization in the framwork of already known models of normal crystal growth, growth by screw dislocations and by two‐dimensional nucleation is discussed. By mathematical treatment, different from Tillers approach, analytical expressions for supersaturation at the crystallisation interface, for superheating at the dissolution interface, growth rate and some other parameters have been obtained for both cases of normal and screw dislocations growth. It is possible to determine the growth mechanism.
Surface Roughening and Surface Self‐diffusion. A Monte Carlo Simulation
Authors: Nenow D. , Trayanov A. , Paunov M.
Published: January 2007

A model for atom diffusion on surface is proposed, the energy barrier for surface self‐diffusion as well as the barrier for diffusion along surface steps being considered. Using a Monte Carlo method, the equilibrium structure of crystal surface is obtained and its effect on the surface self‐diffusion is studied. The mass transfer surface self‐diffusivity Ds and the mean diffusion distance λ are calculated for different temperatures T. A nonlinear Arrhenius plot (log D vs l/T) is obtained. The maximal deviation from linearity occurs at roughening temperature.
Colour Centre in Nd3+‐doped Yttrium Aluminates
Authors: Kvapil Jiřì , Kvapil Jos. , Perner B. , Mánek B. , Blažek K.
Published: January 2007

Spectroscopic and laser properties of YAG:Nd and YAP:Nd grown from the nonstoichiometric melts or those containing Mo and Fe impurity were compared. YAG:Nd grown from the melt with surplus of Y2O3 and annealed in H2 at ∼ 1400 °C have an increased laser performance. Mo admixture in hydrogen annealed YAP:Nd laser crystals suppresses effectively the detrimental action of iron impurity.
Quantum‐chemical Approach to the Dependence of Oxygen Charge on Bond Angle in SiO2
Authors: Pietsch U. , Hübner K.
Published: January 2007

A recently published review on the effective oxygen charge in SiO2 and its dependence on the bond angle of oxygen has shown that, as a rule, solid‐state theoretical calculations lead to the conclusion that the oxygen charge increases with increasing bond angle, whereas quantum‐chemical calculations for limited clusters yield an opposite result, i.e. a decrease of the oxygen charge with increasing oxygen angle. In the present paper it is shown that also a quantum‐chemical approach to the problem, namely a molecular‐orbital calculation for an SiOSi bridge, reveals an increase of the charge of oxygen with its bonding angle, which is, however, relatively weak.
Solvus of KCI:Pb2+ Solid Solution from Flotation Measurements of Single Crystal Density
Authors: Dudnikova V. B. , Urusov V. S.
Published: January 2007

The solvus of KCl:Pb2+ is found in the concentration range from 1.6 × 10−2 to 8 × 10−2 mol.% at temperatures ranging from 450 to 250 °C. The decomposition of the solid solution after various regimes of heat treatment is judged by a change in the crystal density determined by the flotation technique.
Etch Pattern of Gel‐grown Single Crystal of Ammonium Tartrate
Authors: Saraf A. G. , Saraf K. B. , Wani P. A. , Bhoraskar
Published: January 2007

Using optical techniques, a study was carried out of the etch patterns produced, by diluted oxalic acid and sodium hydroxide solution, at 30°C. Point bottomed and flat bottomed rectangular etch pits nucleated at the sites of dislocations parallel to ‘C’ axis of the crystal are observed. Mostly they are isolated, and randomly distributed. Further, on prolonged etching they penetrate deeper and their eccentricity can be attributed to the inclined nature of dislocations.
Effect of Growth Parameters on Spatial Pattern Formation of Cadmium Hydroxide in Agar Gel
Authors: Palaniandavar N. , Gnanam F. D. , Ramasamy P.
Published: January 2007

The interrelated effects of growth parameters on spatial pattern formation of cadmium hydroxide in agar gel medium have been investigated. The main parameters are concentration of electrolytes,pH of the medium, density of the gel, the concentration of parasitic electrolyte and the concentration of additives. The pattern formation is explained on the basis of electrical double layer theory coupled with diffusion. Using Shinohara's revised coagulation concept, the flocculation value is calculated. With suitable combinations of parameter values, dendritic growth and spherulitic growth of cadmium hydroxide crystals have been observed.
Information on the Operating Mode of Decomposition during the Cooling of an Al‐10 at.% Zn Alloy to Various Tq
Authors: Wendrock G. , Löffler H. , Nüssler E. , Reimann G.
Published: January 2007

Information about the operating mode of decomposition during cooling to various Tq were gained by SAXS method. After reaching the Tq wanted the samples were quenched into water of RT and the SAXS intensity curves were measured at RT. Strong evidence was found that below about 175 °C the decomposition starts in this alloy with the nucleation and growth of Guinier‐Preston zones. As proved by other authors, 175 °C is the upper limit temperature Trhm for the onset of the rapid homogeneous nucleation of precipitates.
Morphology and Structure of Thermally Induced Microdefects in High‐Temperature Treated Czochralski‐Silicon
Authors: Reiche M. , Nitzsche W.
Published: January 2007

The morphology and structure of amorphous precipitates grown by thermal annealing in the temperature range from 1100 °C to 1200 °C are investigated by means of highvoltage electron microscopy. It is shown that there exist some characteristic morphological types which are equivalent to the equilibrium forms of the cubic diamond structure itself or which can be derived from these. For the growth process an oxygen diffusion‐controlled mechanism is deduced. Structural aspects are discussed on the basis of this mechanism.
Dislocation Photoconduction and Related Dislocation Memory Effects in KCl Crystals
Authors: Turchányi G.
Published: January 2007

Two types of memory phenomena are discussed, both related to dislocation photoconduction of highly pure and coloured KCl crystals, using the combination of Lyman‐ and F‐illuminations. A very simplified explanation of the dislocation memory effects is given taking into consideration possible changes in the direction of the photocurrents. Some considerations may be of interest for the explanation of photoplastic effects.
Optical Topographic Studies on the Natural Iron Pyrite (FeS2) Crystals
Authors: Prasad P. B. V.
Published: January 2007

Studies on the microtopographical features present on the natural iron disulphide crystals are carried out. Presence of striations, propogating in directions parallel to one of the crystal edges, is noted. Detailed studies reveal that the edges of highly elongated layers, covering the entire crystal face, appear as striations. This aspect is further probed and it is found that the crystals grow by two dimensional nucleation. The features resulting from the interaction of impurity clusters with surface process are studied to determine the nature of the surface process; the features are interpreted as due to growth and not due to dissolution.
Precipitation of Alkaline‐Earth Metal Silicate Hydrates from Aqueous Solution: Ionic Equilibria, Crystalline Phases and Precipitation Mechanisms
Authors: Packter A.
Published: January 2007

The precipitations of magnesium, calcium, strontium, barium and zinc silicate hydrates from aqueous solutions and suspensions at ambient temperature to 200 °C are surveyed. The relevant ionic equilibria (silicate and polysilicate anion formation, hydroxocation formation, alkaline‐earth metal silicate hydrate and hydroxide precipitation from supersaturated solution) that may influence these precipitations are examined. ‐ The microcrystalline and crystalline phases precipitated in systems of different cation/silicate compositions and temperatures are tabulated. Precipitation mechanisms are analysed.
Epitaxial Growth of Silver Bromide on Mica from the Melt
Authors: Fischbach Harald
Published: January 2007

It is shown that it is possible to grow silver bromide crystals with definite crystallographic orientation by solidification of liquid silver bromide between mica and quartz plates by cooling the mica side. The orientation is (111). The maximum dimensions were 15mm × 15 mm × 1 mm. The surface is investigated by electron reflection (RHEED). The crystals have a smooth surface and can be used for optical application without surface reconstruction.
Hydrothermal Synthesis of Zeolite Crystals Using Natural Scolecite
Authors: Joshi M. S. , Choudhari A. L. , Kanitkar R. G.
Published: January 2007

Natural scolecite is converted into analcime type zeolite by hydrothemal method at 180 °C at autogeneous pressure for 24 to 160 hours growth runs. Mordenite is detected in the final product. Cube and spheroid crystals of the products are illustrated and described. Crystals synthesized are characterized by X‐ray diffraction, infrared spectroscopy EDAX and scanning electron microscopy. Particle size is estimated as 20–60 microns, induction period for nucleation as 12 hrs, and lattice parameter of cube crystals as 13.70 Å. Mechanism of growth, influence of anions and duration of growth etc. are discussed. It is established that the crystals grow in the system Na2OAl2O3SiO2H2O.
Crystal Structure Phase Transitions in the Perovskites A(Cu1−xMnx)Mn4O12(A = Na+, Ca2+, Y3+, La3+)
Authors: Troyanchuk I. O. , Balyko L. V. , Bashkirov L. A.
Published: January 2007

X‐Ray diffraction and neutronographical studies on the crystal structure of the perovskitelike compounds A(Cu1−xMnx)Mn4O12 have been undertaken. It has been shown that the samples with 50% of Mn3+ in the octahedral sites have a cubic unit cell, while the samples with higher Mn3+ composition may have a monoclinic or rhombohedral unit cell. The temperature increase raises the symmetry to the cubic one. The concentration ranges with different symmetry type have been determined. The lowering of the symmetry of the unit cell is due to the cooperative Jahn‐Teller effect.
Observation of Intermediate Smectic A Structure at the Phase Transition Nematic‐Smectic C in 4,4′‐di‐n‐Heptyloxyazoxybenzene
Authors: Simova P. , Petrov M.
Published: January 2007

Using different boundary conditions in thin film of 4,4′‐di‐n‐heptyloxyazoxy benzene and studying the microscopic textures as well as the depolarized Rayleigh light scattering, an intermediate smectic A‐like state during the nematic‐smectic C phase transition was observed.
The Interface Unstability of the Solubility Boundary in the Gradient Temperature Zone Melting Method
Authors: Peev N. S.
Published: January 2007

In the present work the interface unstability of the solubility boundary in the gradient temperature zone melting method is considered for the case of large breach amplitude and great wave length. The critical value of the amplitude at which the breach begins to form as a drop in front of the solubility boundary is determined. It is assumed that the crystallization and the solubility processes are accomplished by the dislocational and normal mechanisms.
Optical Properties of CuInSe2 Single Crystals Grown by the Vertical Bridgman Technique
Authors: Neumann H. , Hörig W. , Tomlinson R. D. , Avgerinos N.
Published: January 2007

The optical absorption near the fundamental edge of n‐type CuInSe2 single crystals was studied for samples having different impurity concentrations. It is found that with increasing impurity concentration the gap energy decreases whilst the tail absorption below the edge and its characteristic energy increase. It is concluded that band‐gap narrowing due to high ionized impurity concentrations plays an important role in CuInSe2 single crystals.
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Authors: Todes O. M. , [Russian Text Ignored]  , [Russian Text Ignored]
Published: January 2007

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Studies on the Effect of Unsaturated Homologues on the Crystallization of Stearic Acid
Authors: Prasad P. B. V. , Sato K.
Published: January 2007

The unsaturated fatty acids play decisive role in the activity of biological membranes. The interaction between saturated and unsaturated fatty acids during the condensation process is therefore of great importance. Studies on the crystallization of stearic acid (a typical saturated acid), in presence of oleic acid and linoleic acid (typical unsaturated acids), were carried out to determine the extent of interaction. Results indicated that interaction between saturated and unsaturated molecules is almost absent. It can be derived from the findings that these molecules might participate in biological or biochemical processes, as if they are entirely different types of molecules.
Structural Studies on Ni75(SnSi)25 and Ni75(SnBi)25 Alloys
Authors: Shadangi S. K. , Singh M. , Panda S. C. , Bhan S.
Published: January 2007

Ternary alloys on the quasi‐binary system Ni3Sn(r) in equilibrium condition. It has been observed that these phases undergo transformations at high temperatures but upto 500 °C room temperature modifications are stable. The two phases do not have any appreciable solid solubility in either of them. The phase Ni3Si(r) crystallizes in to Cu3Au (Li2) structure where as Ni3Sn(r) is based on c.p.h. structure with a = 5.305 A°, c = 4.254 A°. No new ternary phase has been detected in Ni3SnNi3Si section.

The investigated alloys of the NiSnBi system contain 75 at.% Ni. All the ternary alloys show simultaneous occurrence of three phases, namely Ni3Sn(r), NiBi and Ni(Sn) in equilibrium state. The phase NiBi has NiAs(B8) type of structure. Due to non‐existence of isostructural phases in the two binary systems (NiSn and NiBi), single solid solution phases are not formed. Widely differing atomic sizes of nickel and bismuth atoms restrict the formation of solid solution of bismuth in nickel in contrast to Ni(Sn) where atomic size factor is favourable.