bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrooptical coefficients and temperature and pressure derivatives of the elastic constants of tetragonal Li2B4O7
Authors: Bohtý L. , Haussühl S. , Liebertz J. 
Published: January 2007

AbstractNew values for the following properties of tetragonal Li2B4O7 are reported: dielectric, electrostrictive, electrooptic, elastic, thermoelastic and piezoelastic constants, coefficients of thermal expansion and indices of refraction. These values are considered to be of superior precision compared to earlier published data. Most elastic constants possess positive temperature derivatives. This anomalous behaviour is not reflected in the pressure derivatives. The electrooptic effects are not large enough to compete with other materials used for technical applications.
On the correlation of lattice defects to HUBER‐etch pit morphologies on (001) surface of InP
Authors: Knauer A. , Zeimer U. , Sprenger R. 
Published: January 2007

AbstractVarious analytical techniques (defect etching, optical microscopy, X‐ray topography (XRT), cathodoluminescence (CL) were combined to get information about the real structure of Sn‐ and S‐doped LECInP. The S‐pits, produced by the HUBER‐etch, were not only caused by microdefects, as it was described in literature. We found a correlation between S‐pits and special types of dislocations.
X‐ray studies of thermal expansion and phase transitions in (NH4)2SbF5 crystals
Authors: Waśkowska A. , Czapla Z. 
Published: January 2007

AbstractX‐ray diffraction studies of phase transitions in (NH4)2SbF3 single crystals have been made by using the Bond‐type diffractometer for high‐precision measurements of the unit‐cell dimensions in a function of temperature. The principal linear thermal expansion coefficients and the linear Eulerian strain tensor have been calculated in the temperature interval 110 – 298 K. The phase transition diagram was proposed and the sequence of the phases has been compared with the results of other experimental techniques (NMR, NQR, DTA, electrophysical methods).
Microhardness of ZnSe and its change by proton implantation
Authors: Ascheron C. , Neumann H. , Kühn G. , Haase C. 
Published: January 2007

AbstractThe load dependence of the Vickers microhardness of the (001) plane of ZnSe crystals is studied in the load range from 5 to 160 g. From a comparison with literature data it is concluded that the microhardness of ZnSe is anisotropic according to H(001) ≈ H(111) > H (110). The indentation size effect of the (001) plane is less pronounced than that of the (110) plane. Proton implantation is found to increase the microhardness of ZnSe.
Investigations of the crystal growth of PbMoO4 by the Czochralski method
Authors: Pfeifer E. , Rudolph P. 
Published: January 2007

AbstractThe thermal conditions at the liquid/solid interface are characterized by temperature measurements in the melt and on the growing crystal with 〈001〉‐seed orientation. The thermal boundary layer was determined, from which the relation of effective thermal conductivity of the liquid and solid phase was found to be λl,eff/λs,eff = 0.25. The liquid/solid interface is extremly convex towards the melt and has a conical shape. When the crystal diameter reaches a certain value the cone was truncated with the formation of a facet in the centre. This typical interface shape is mainly the result of a difference between the effective thermal conductivity of melt and crystal.
On the thermodynamic stability of disperse systems
Authors: Bliznakov G. M. , Delineshev Sv. P. 
Published: January 2007

AbstractInvestigation has been carried out on the effect of the surface activity of capillary or surface active substances (impurities), called surfactants (i.e. the effect of the lowering (Δσ) of the specific surface energy after impurity adsorption at the solid/gas, solid/liquid, liquid/gas or liquid/liquid interface), on the thermodynamic equilibrium in a polydisperse system. Attention has been paid to the fact that the presence of a surfactant with an activity within the range 0 < Δσ < σ0 (where σ0 is the specific surface energy of an adsorption‐free interface) reduces the thermodynamic driving force for the appearance of the Gibbs‐Thomson effect and for the recondensation (recrystallization) processes in the heterogeneous polydisperse system.It is shown that with an impurity activity Δσ = σ0, the supersaturation becomes zero and the condensed phase formations should be, irrespective of their size and shape, in equilibrium with one another because their vapour pressure becomes equal to that of an infinitely large phase. In this case the Gibbs‐Thomson effect completely disappears, the system become thermodynamically stable and, regardless of its polydispersity, it can exist infinitely long. The behaviour of such a heterogeneous system, which is far from its critical point (the system temperature is T ≪ Tcritical), is similar to the behaviour of a system in the region of its critical point: the surface tension becomes nearly equal to zero, and the fluctuations sharply increase.The case when the surfactant activity is so high (Δσ > σ0) that σa = σ0 − Δσ < 0 (σa, specific surface energy of the interface in the presence of a surfactant), is of special interest. It represents a paradox in the phase formation theory: as a result of the adsorption of an impurity with such a high activity, the condensed phase surface would be destabilized and the phase would be spontaneously dispersed.
A contribution of diffusion‐induced structural changes on the anisotropy of the diffusion of P in Si
Authors: Larikov L. N. , Bogdanov E. I. , Maximenko E. A. 
Published: January 2007

AbstractIt was investigated the contribution of diffusion‐induced structural changes on the anisotropy of P diffusion into the monocrystalline Si. Generation and distribution of dislocations by solute diffusion of phosphorus in silicon (100) and (111) provides for further different depth penetration of diffusion precipitation up to anisotropic diffusion in cubic crystals.
Infrared lattice vibrations of In2O3
Authors: Sobotta H. , Neumann H. , Kühn G. , Riede V. 
Published: January 2007

AbstractInfrared reflectivity spectra of In2O3 samples pressed from powdered material are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. A Kramers‐Kronig analysis of the spectra reveals eleven vibrational modes. The results obtained are compared with group theoretical predictions and with existing experimental data.
Dynamic etching of natural rhombohedral calcite cleavage planes
Authors: Mehta B. J. , Sidpara G. R. 
Published: January 2007

AbstractDynamic etching of natural rhombohedral calcite cleavage plane in low concentration of monocarboxylic acid (such as formic, acetic and propionic acids) is studied and interesting results are obtained. Eccentricity of rhombic etch pits increase indefinitely as stirring rate increase in low concentration of monocarboxylic acids, whereas peak value of eccentricity is obtained with stirring rate when there is a change in etch pit morphology. Change in etch pit morphology and change in eccentricity with stirring rate is explained with the help of lateral reaction rates along various directions. Eccentricity variation with stirring rate is compared with concentration variation with concentration of different monocarboxylic acids.
New X‐ray rietveld refinement of kaolinite from Keokuk, Iowa
Authors: Smrčok Ľ. , Gyepesová D. , Chmielová M. 
Published: January 2007

AbstractThe positions of 13 non‐hydrogen atoms in the structure of kaolinite from Keokuk, Iowa, were refined in the space group C1 using the constrained X‐ray Rietveld refinement. The precision and accuracy of the atomic positions are better than those previously reported. The most frequent e.s.d.'s of the positional parameters range from 0.003 to 0.005; the SiO bond distances are from the interval 1.56(4)–1.68(3) Å, and the AlO from 1.80 (5) to 2.07 (5) Å. The ditrigonalization angle α characteristic for tetrahedral sheet was found to be 9°, this value is in good agreement with the 11° reported from single crystal data. The correction for preferred orientation was in the form of exp (G cos (2α)), the final factors of agreement were Rwp = 23.1%, RF = 9.2% and S = 1.4.
Mathematical modelling of crystal growth processes in gel
Authors: Cipanov A. V. , Goshka L. L. , Kolosov S. I. , Ruzov V. P. 
Published: January 2007

AbstractThis paper suggests a mathematical model of processes occurring during nucleation and crystal growth in gels. Calculations showed that there is a locality in a gel that provides the best conditions for nucleation and growing of crystals. Possible reasons restricting crystal growth are discussed. The qualitative agreement of calculations and experimental data allows to assume that the model suggested adequately describes processes occurring during crystal growth. Experimental data interpretation in terms of the model allowed to obtain the diffusion constants of reagents in a gel and the crystal growth rate.
Electron microscopic investigations on optical oxide single crystal
Authors: Malicskó L. 
Published: January 2007

AbstractScanning and transmission electron microscopic methods including energy dispersive X‐ray spectrometry and reflection high energy electron diffraction as well, were used for the inspection of the growth, the shape‐processing and the laser irradiation induced defects in pure and doped optical oxyde single crystals. Some general results will be presented and discussed in the light of theoretical predictions.
Reversible and irreversible field‐induced deformations in planar and weakly‐tilted smectic C phases
Authors: Pelzl G. , Schiller P. , Demus D. 
Published: January 2007

AbstractIt was found that the dielectric reorientation of planar or weakly‐tilted Sc phases can take place by domain wall motion accompanied by hysteresis effect. For special boundary conditions the field‐induced deformations can become irreversible. At high electric fields an irreversible transition of a planar texture into a schlieren texture is observed. The experimental results are interpreted threoretically.
The investigations on the synthesis of zeolite ZSM‐5 (II)
Authors: Wilkosz J. , Stobiecka E. , Dudek B. 
Published: January 2007

AbstractPhysical parameters, i.e. the effect of temperature and time of crystallization on the content of zeolite ZSM‐5 in the obtained preparations were investigated. Two standard reacting mixtures were tested. The mixture of ethanol and ammonia was used as a templating agent. The phase composition of the preparations was determined on the ground of the X‐ray diffraction method.
Melting and crystallization of silicon layers on insulator with millisecond lamp heating
Authors: Aleksandrov L. N. , Zinovyev V. A. 
Published: January 2007

AbstractMelting and crystallization of silicon layers in a SOI structure (SiSiO2Si) at millisecond lamp heating have been studied by model calculations using the solution of conduction equation. Pulse heating conditions that do not lead to silicon substrate melting under SiO2 have been determined. For pulses of 1 and 4.4 ms duration the silicon melt lifetime on the SiO2 surface has been estimated. The lengths of the crystal oriented growth from windows in the SiO2 layer that open the single‐crystalline silicon substrate have been measured (25 and 64 μm).
Some results of microscopic and X‐ray investigations of calcium carbide
Authors: Hahne B. , Gordziel W. , Meerbote E. 
Published: January 2007

AbstractThe structure of calcium carbide is investigated using thin sections and ground sections. Depending on chemical and other factors, calcium carbide occurs in three types of structure, which are interpreted as conversion products resulting from a high‐temperature structure.The pavement‐like structure containing CaC2‐I is present in industrial carbide with a low content of nitrogen. With increasing fraction of lignite high‐temperature coke used for carbon supply as a substitute for coal coke in the production of carbide, the particle size decreases, and the micro hardness increases.The interlocked structure with CaC2‐II and higher contents of nitrogen, which has been detected in carbide produced in the laboratory, is extremely dense. No grain sizes can be given. This kind of carbide produced in the laboratory has a lower micro hardness than industrial carbide.The mixed crystal structure is typical of carbide with a high content of sulphur. CaC2—CaS‐I is present as a phase.In all three types, the respective carbide phases have a marked lamellar structure. No typical shapes of crystals can be detected. In consequence of poor crystal formation, the information obtained with a microscope about the phases contained in the material investigated is complemented by X‐ray diffraction methods.
Photoemission core level and satellite study of TixRu1−xoxide layers
Authors: Wagner N. , Horx M. , Jacobs M. 
Published: January 2007

AbstractCombined photoemission core level and satellite structure investigations of pyrolytic titanium‐rich TixRu1−x‐oxide layers (0.90 ≦ x ≦ 0.97) and RuO2 layers on titanium are used to gain structural and compositional information about these electro‐catalytically active surfaces. By means of this method deviations from stoichiometry, the formation of carbon interstitials and the growth of anatase by ruthenium loss could be pointed out.
Kinetic investigations within the transition region from polyhedral to skeletal growth mode (III). Growth kinetics of the basal face of zinc single crystals and its edge under diffusion conditions
Authors: Iwanov D. 
Published: January 2007

AbstractThe growth kinetics of the basal face and its edge of zinc single crystals grown from zinc vapours in the presence of argon at pressures 5 – 250 Torr has been investigated simultaneously. The alterations of the crystal size R and the length of the basal edge a with time t have been measured at constant temperature and supersaturation. It is shown that the R2(t) and a2(t) dependences change their initial shape into linear at one and the same moment. It is established that the transition from a kinetic to a diffusion regime can be determined both by the kinetic critical size Rk and by the kinetic critical size ak. It is found also that in the kinetic regime the lateral growth rate of the basal edge is higher than the normal growth rate of the {0001} face. During the growth in a diffusion regime the R2(t) and a2(t) curves of a given single crystal become parallel, due to the isotropic character of the transport processes of the material. The rate determining role of the diffusion in the parent phase on the growth of the basal face and its edge is demonstrated.
On the chemical vapour transport of nickel titanate with selenium tetrachloride
Authors: Bieger W. , Piekarczyk W. , Krabbes G. , Stöver G. , van Hai Ngyen 
Published: January 2007

AbstractThe chemical vapour transport (CVT) of NiTiO3 with SeCl4 is reported. In addition to small NiTiO3 crystals a more or less quantity of solid NiCl2 is deposited in the deposition zone. At higher temperature gradients the solid which is deposited besides NiCl2 is NiO. The transport behaviour is satisfactory explained using two thermodynamical models: the model of connected equilibrium states and the four‐stage model.
Lattice parameter variation in inp related to the dopant element and doping level
Authors: Knauer A. , Kräusslich J. , Kittner R. , Staske R. , Bärwolff A. 
Published: January 2007

AbstractThe variation of the lattice constant was determined across (001) InP wafers from 〈111〉 grown LEC INP: S and InP: Sn + Ga + As monocrystals. The variation correlates to the free carrier distribution. The enrichment of dopants results in lattice spacing in the crystal core (especially for InP: Sn + Ga + As), which occupy a larger region as dopant enrichment do.
In‐situ doping of LPCVD poly silicon (II). Temperature influence
Authors: Kühne H. , Puk P. , Gericke M. , Bertoldi W. 
Published: January 2007

AbstractPoly silicon deposition by pyrolysis of silane under low pressure conditions has been investigated with respect to the influence of temperature when simultaneously in‐situ doping of the deposited layer takes place.The growth rate of poly silicon is retarded in the presence of phosphine provided that a certain lower PH3/SiH4‐ratio has been exceeded. It has been shown how that lower ratio depends on temperature.Increasing PH3/SiH4‐ratio not only slows down layer growth rate but also the apparent activation energy of the layer forming reaction. An empirical equation describing the temperature dependence of that activation energy has been derived. Phosphine adsorption has been discussed as a cause of both layer growth rate and activation energy reduction. Additionally, incorporation of phosphorus during layer growth has been investigated with respect to the total amount and the electrically active concentration, the latter measured after a postdeposition anneal at 1000 °C.
Defects in quartz crystals initiated during their hydrothermal growth
Authors: Nanev N. , Wilkens M. 
Published: January 2007

AbstractA complex investigation (performed by means of X‐ray topography, γ‐ray diffractometry, optical methods) of the defects in as‐grown and tempered quartz single crystals has been described. The results should contribute to the improvement of the quality of hydrothermally synthetized quartz.
Influence of annealing conditions on structural properties of YBaCu oxide superconductors
Authors: Rauschenbach B. , Neelmeijer C. , Schuster G. , Knothe P. , Erfurth W. 
Published: January 2007

AbstractThe chemical composition, the topography, and the defect structure of high‐temperature superconducting YBaCu oxide samples have been studied in dependence on the annealing conditions by scanning electron microscopy, energy dispersive X‐ray analysis, Rutherford backscattering, nuclear reaction analysis, and transmission electron microscopy. The topography is characterized by smooth and rough grains. The chemical composition of samples varies in dependence on the annealing time and temperature. The microstructure of the superconducting material is dominated by a lamellar twin structure.
Filled SAphases in binary liquid crystalline systems of terminal‐nonpolar compounds (III). The role of the molecule length of the rod‐like component
Authors: Pelzl G. , Humke A. , Diele S. , Ziebarth S. , Weissflog W. , Demus D. 
Published: January 2007

AbstractThe phase diagrams of 8 binary systems of liquid crystals are presented whereby one component is a “biswallow tailed” compound and the second component is a member of the homologous series of 4,4′‐bis‐n‐alkyloxy‐azoxybenzenes. In all phase diagrams studied induced smectic A phases occur. X‐ray investigations give evidence that in the binary systems of short‐chain homologues the layer spacing d of the smectic A phase is clearly greater than the average molecular length L̄, whereas in the systems of long‐chain homologoues d is found to be somewhat smaller than L̄. The results are interpreted on the basis of a simple packing model.
Optical absorption spectra of magnesium‐implanted GaP
Authors: Hörig W. , Bouamama Kh. , Neumann H. , Nobes M. J. 
Published: January 2007

AbstractOptical absorption spectra of magnesium‐implanted GaP single crystals are measured in the photon energy range below the fundamental edge. It is found that implantation results in the formation of exponential absorption tails with tailing energies up to about 0.8 eV and absorption coefficients up to about 105 cm−1 at 2.0 eV. The results are compared with optical measurements on GaP single crystals implanted with other ions and with optical absorption data of amorphous GaP.
Effect of temperature on dielectric properties of SnO2/Sb2O3 mixed thin films
Authors: Kumar J. Siva , Rao K. V. Styatanarayana , Rao U. V. Subba 
Published: January 2007

AbstractThin films of various thicknesses in the MIM structure have been prepared from the powder of SnO2/Sb2O3 mixed sample by the thermal evaporation technique in a vacuum of 10−5 Torr. Dielectric properties of SnO2/Sb2O3 mixed thin films have been studied with temperature starting from LNT to RT and above RT and frequency ranging from 100 Hz to 16 kHz. The activation energy for the migration of charge carriers in SnO2/Sb2O3 mixed thin films has been calculated and it is found to be 0.23 eV. The results thus obtained on dielectric properties of SnO2/Sb2O3 mixed thin films are presented and discussed.
The current understanding of epitaxial silicon layer doping in the light of modelling and theory development (X). Once more autodoping mechanism
Authors: Kühne H. 
Published: January 2007

AbstractSpecial disadvantages associated with interpreting and describing the course of autodoping profiles by means of applying the “consequent” as well as the “improved” conception of dopant incorporation will be discussed. In order to find a solution of the problem special lateral autodoping experiments were carried out. Substrate wafer surfaces were exposed to a defined arsine flow under epitaxy‐near conditions but without the supply of silane. After the arsine flow had been stopped a thin epitaxial layer was intrinsically deposited on the exposed surfaces and after that, the dopant dose incorporated measured. In this way a time‐dependent increase of dopant dose in the layer with adsorption‐like behaviour and a growth rate dependent increase with gas‐phase‐doping‐like behaviour has been confirmed.From the results desorption rate constant as well as its temperature dependence has been evaluated and a mechanism of autodoping concluded. The latter is characterized by both adsorption and desorption of dopants. Adsorption is expected to take place mainly outside of substrate wafer surface before layer growth begins. Desorption from those adsorption regions proceeds after layer growth has started leading to a time‐dependent, decaying partial pressure of dopants in the gas. That partial pressure of dopants regulates autodoping.
IR‐ and 27Al‐NMR‐spectroscopic studies on thermal decomposition products of basic aluminium chlorides
Authors: Brand P. , Müller D. , Gessner W. 
Published: January 2007

AbstractThe formation of corundum by thermal decomposition of basic aluminium chlorides was studies by means of spectroscopic methods (IR, 27Al‐NMR). It was tried to get information about the short‐range order, because favourable structural conditions in the amorphous precursors for the formation of corundum were supposed. For this purpose IR‐spectroscopy turns out to be the less informative method. 27Al‐NMR‐spectra show resonances of tetrahedrally, octahedrally and fivefold coordinated Al in the decomposition products. The corundum proceeds from sixfold and fivefold coordinated Al.
On steady‐state modelling of the high‐pressure liquid encapsulated czochralski (HPLEC) crystal growth of InP (Conduction Model)
Authors: Böttcher K. , Krüger A. , Schleusener B. 
Published: January 2007

AbstractThe steady‐state temperature distribution of the growth system is calculated at various stages of the growth process. The results indicate a serious influence of the thermal transparency of the B2O3. The heater power which has to be adjusted in order to achieve a constant diameter growth is calculated as an inverse problem.
A new method of enlarging the cross‐section of KDP using ADP crystals as seed
Authors: Feng Pan , Jinkui Liang , Genbo Su , Qinglan Zhao , Youping He , Yisen Huang 
Published: January 2007

AbstractA new method of enlarging the cross‐section of KDP crystals using an easily enlarged ADP crystal as seed for a KDP crystal, has been investigated. The growth characteristics of the ADP seeds (Z‐plate, cap, and parallelly spliced seeds) at KDP supersaturation have been observed. Chemical etching was used to characterize the grown crystals, and chemical analysis to determine the composition of both the region of the seed and the grown crystal. The mechanism of this kind of growth is discussed. In conclusion this growing method should be qualified for enlarging the cross‐section of KDP crystals.