bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth rate dispersion in batch and continuous configurations
Authors: Tulke A. , Offermann H. 
Published: January 2007

AbstractThe existing models describing growth rate dispersion don't consider a healing process of crystal damages or surface defects. In this paper a model is presented which takes into account such a healing process. With regard to the new model formulas, characterizing the crystal size distribution, are derived from the population balance and discussed. The considerations are extended to continuous crystallizers.
Crystal structure of a daturalactone – A withanolide
Authors: Padha Naresh , Kalyandas  , Dhar K. L. , Goswami K. N. 
Published: January 2007

AbstractThe crystal structure of a daturalactone derivative has been determined by X‐ray structural analysis. The compound crystallizes in orthorhomic space group P212121 with cell parameters a ‐ 15.141(1) Å, b ‐ 18.425(1) Å, c ‐ 19.251(2) Å. The structure was solved by direct methods and refined to R ‐ 0.082. The asymmetric unit contains two non‐equivalent molecules. Extensive hydrogen bonding is present. The conformations of the rings are A: a distorted half‐chair, B: a perfect half‐chair, C: a chair, D: an envelope‐half chair and E: a twist boat. Ring junctions A/B, B/C, C/D are all trans fused. Methyl carbons C(18), C(19), C(27) and the lactone moiety is β‐oriented whereas the methyl carbons C(21) and C(28) are α‐oriented.
The crystal structure of SrCl2 and BaCl2 hemihydrates by powder diffraction
Authors: Łasocha W. , Michalec M. 
Published: January 2007

AbstractThe crystal structures of isomorphous SrCl2 and BaCl2 hemihydrates were solved by powder diffraction method. Strontium and barium atoms are coordinated either by nine chloride atoms or by seven chloride and two oxygen atoms. Space group: Pmmn(59), lattice parameters: a ‐ 15.976(1), b ‐ 4.260(5), c ‐ 8.090(1) and a ‐ 16.477(5), b ‐ 4.555(1), c ‐ 8.330(3) Å, for strontium and barium compound, respectively. Rietveld refinement results in the discrepancy factors RB ‐ 10.85, Rwp ‐ 12.71% and RB ‐ 4.50% for SrCl2 and BaCl2 hemihydrate, respectively.
Infrared vibrational Modes in Tl3SbS3, Tl3AsS3, and Tl3AsSe3 crystals
Authors: Syrbu N. N. , Krasovsky V. T. , Grincheshen I. N. 
Published: January 2007

AbstractReflectivity spectra of Tl3SbS3, Tl3AsS3, and Tl3AsSe3 crystals have been investigated in the wave number range 50–600 cm−1 for the polarizations E∥c and E⟂c. The fundamental phonon parameters, the limiting dielectric constants ϵ∞ and ϵS and the reflectivity spectra contours have been calculated by using classical dispersion relations for both E∥c and E⟂c configurations. The Szigeti effective charges and the relative ion charges of As, Tl, Sb, Se, S anions and cations have been calculated in dependence on the incident light polarization.
Experimental confirmation of the peculiar behaviour of the coherent‐type twin boundaries in sphalerite crystals
Authors: Minchev G. M. , Pramatarova L. D. , Podor B. , Szabo J. 
Published: January 2007

AbstractThis paper presents an experimental confirmation of the peculiar behaviour of coherent twin boundaries in sphalerite crystals through a “two step” experimental procedure involving free abrasive polishing for the “developing” of the stress pattern and infrared whole‐sample optical reflection (“magic mirror”) for the registration. The results are in accordance with the novel static atomistic simulations of the grain boundaries.
Structural investigation on the influence of clathration of metal amine complexes and its effective parameters
Authors: El‐Shabiny A. M. , El‐Zein S. M. 
Published: January 2007

AbstractThe clathrates of Ni‐ and Co‐Werner complexes with o‐, m‐, and p‐xylenes were studied in order to explain the controlling factors affecting clathration. The complexes and their clathrates have been investigated using an analytical X‐ray powder diffraction procedure for the structure determination. It was found that clathration degrades the lattice symmetry, deforms the crystal and decreases the cell volum when accompanied by a change in the crystallographic system. The possibility of clathration increases as the cell volume of the complex (host) increases. Lower polarity and better fitting into the complex lattice increase selectively. Thus, clathration is strictly governed by the shape and polarity of the guest molecule rather than its volume.
On the (MgxNi1–x)SeO4 · 6 H2O and (MgxCu1–x)SeO4 · 5 H2O mixed crystal formation
Authors: Stoilova D. , Ojkova T. , Staneva D. 
Published: January 2007

AbstractMixed crystals (MgxNi1–x)SeO4 · 6 H2O and (MgxCu1–x)SeO4 · 5 H2O have been prepared studying the solubility in the MgSeO4–NiSeO4–H2O and MgSeO4–CuSeO4–H2O systems at 25 °C. It has been shown that the monoclinic structure of MgSeO4 · 6 H2O is unstable and undergoes a change into tetragonal structure due to the included nickel ions (about 4 at %). The lattice parameters of (MgxNi 1–x)SeO4 6 H2O have been calculated. It has been established that the magnesium ions incorporate isodimorphously in the crystal structure of CuSeO4 · 5 H2O which could be an indication of the existence of MgSeO4 · 5 H2O isostructural with the triclinic CuSeO4 5 H2O. The distribution coefficients of the salt components between the liquid and solid phases have been calculated.
Growth of CdGeAs2 single crystals by a microprocessor‐controlled bridgman system
Authors: Manimaran M. , Ramasamy P. 
Published: January 2007

AbstractA microprocessor‐controlled Bridgman system was designed and fabricated for the growth of II‐IV‐V2 compounds and one of this group of compounds CdGeAs2 has been grown using a two‐zone vertical Bridgman systein. The grown crystals have been characterized by X‐ray and Hall effect.
Temperature‐gradient‐double‐crucible method for high‐temperature solution growth
Authors: Jung P. A. , Schwabe D. , Scharmann A. 
Published: January 2007

AbstractWe report on a special technique for high‐temperature solution growth (flux‐), which can be used to grow compounds which have only a small solubility in the flux or only exist in a small existence range (concerning temperature and concentration). By two crucibles placed into one another, an inner growth region will be separated from an outer solution region. The regions are connected by holes in the inner crucible. By this method BaSO4 crystals of high quality are grown from NaNO3 flux and LiCl–KCl flux. Growth experiments using this method were done with the incongruently melting high‐temperature superconductor YBa2Cu3O7‐δ.
X‐ray investigations on the defect structure of KCl with Cd++ impurities
Authors: Saravanan R. , Mohanlal S. K. 
Published: January 2007

AbstractA systematic defect characterization by X‐ray diffraction was carried out on crystalline KCl system with Cd++ impurities at various levels, viz. 2, 4, 6, 8, and 10 mole%. Quantitative estimation of the amount and nature of defects was done from the integrated X‐ray intensity measurements of the samples. Further analyses of the experimental data indicate enhancement of the Debye‐Waller factor with concentration of Cd++ impurities. The measured density and the cell constant values at room temperature yield vacancy estimations for the system. The observed change of Bravais lattice of the system for Cd++ concentrations from 4 mole% with appreciable enhancement of intensity of Bragg reflections of mixed indices are reported and discussed.
The Ln–Ba–Cu–O (Ln = Lanthanoid) systems: Compounds and compatibilities in air at 900–980°C
Authors: Chodorowicz‐ba̧k A. , Hodorowicz E. , Hodorowicz S. A. 
Published: January 2007

AbstractComparison of phases observed in air at 900–980°C in the Ln–Ba–Cu–O (Ln = Lanthanoid) systems is reported. On the basis of the occurrence of compounds found in these Ln2O3–BaCO3–CuO systems they must be divided into at least three subgroups: the first is characteristic of La, Pr and Nd, the second specific for Sm and Eu, and the third common to the smaller lanthanoids, the Y‐type elements, with some variation within the groups.
Enantiomorphism in sodium chlorate crystals
Authors: Szurgot Jadwiga , Szurgot Marian 
Published: January 2007

AbstractCreation of enantiomorphous forms in sodium chlorate and enantiomorphous nature of surface micromorphology were studied by optical microscopy. It was shown that when the small number of crystals nucleates spontaneously in unstirred, unseeded solutions then exclusively left‐ (L) or right‐handed (D) crystals can be formed. At the large number of nucleated crystals the probability of the creation of L and D form is nearly the same. L and D crystals can be distinguished by the shape of growth or dissolution centers.
The structure of mixed crystals KNO3. x NH4NO3
Authors: Galdecki Z. , Czurak W. , Fruziński A. , Dejewska B. 
Published: January 2007

AbstractFive salts of KNO3. x NH4NO3 with different x values have been synthesized and their structures have been solved and refined. X values obtained from refined fractional occupation number of K atom are in accord with x obtained from chemical analysis. The linear dependence of volume cell on obtained x has been given.
On the anharmonic vibrations in crystalline silicon
Authors: Saravanan R. , Mohanlal S. K. , Netaji M. 
Published: January 2007

AbstractUsing a total of 1052 Bragg reflections of silicon, an X‐ray investigation has been carried out to deduce the anharmonic thermal parameter β, apart from the estimation of the harmonic contribution of the thermal vibration at room temperature. Reflections of type h + k + l = 4n, and 4n ± 1 were used to estimate these parameters using MoK α radiation and a Nonius CAD‐4 X‐ray diffractometer. We obtain Bsi, = 0.451(0.008) Å2 and βsi = 0.279(2.630) eV Å−3 with R = 3.12%. The present B and β values are in very good agreement with the earlier studies.
Influence of non‐stoichiometry on the recombination activity of dislocations in undoped semi‐insulating GaAs crystals
Authors: Glinchuk K. D. , Prokhorovich A. V. 
Published: January 2007

AbstractThe effect of non‐stoichiometry of gallium arsenide melt composition on the recombination activity of dislocations in undoped semi‐insulating GaAs crystals is studied and analyzed. It is shown that the deviation from the stoichiometric melt composition is one of the major factors affecting the recombination activity of dislocations in undoped semi‐insulating GaAs crystals. namely: the recombination activity of dislocations is increased when the arsenic‐rich melt is used, and, on the contrary, is decreased when the gallium‐rich melt is used. The regularities observed are explained by the complex processes of interaction of dislocations with the non‐stoichiometry‐induced intrinsic point defects.
Crystal structure of a furo‐[3,2‐g]‐[1]‐benzopyran‐7‐one derivative
Authors: Padha Naresh , Subramanian E. , Dass A. K. , Mazumdar S. K. , Goswami K. N. 
Published: January 2007

AbstractThe crystal structure of 9–(1,1‐dimethyl–2‐propenyl)‐4‐hydroxy‐7H‐Furo‐[3,2‐g]‐benzopyran‐7‐one has been determined from X‐ray diffraction data. The compound crystallizes in the monoclinic space group C2/c with unit cell parameters a = 8.976(3) Å, b = 16.621(2) Å, c = 17.818(2) Å, β = 95.79(2) Å. The gross structure was determined by direct methods and refined to a final value of R = 0.053. The three ring framework of the molecule is nearly planar. The side chain attached at the atomic position C(9) possesses significant foldings and has been found inclined to the ring system of the molecule.
X‐ray diffraction investigation of structure perfection state of silicon crystals after irradiation by fast uranium ions
Authors: Auleytner Prof.J. , Khrupa V. , Briginets A. , Skorokhold M. , Datsenko Prof.L. 
Published: January 2007

AbstractThe results, obtained from U‐implanted silicon crystals, are presented. Disclocation‐free Si‐wafers (200 μm thick) were implanted with 16 MeV/n U‐ions using Darmstadt accelerator. The applied dose was of 4.4 · 1012 i/cm2. During implantation the crystal was covered by 2 mm thick copper mask with a circular hole of 8 mm diameter. We present the results which were obtained 4 years after performing the implantation. During this time the crystal was kept at the room temperature. Various X‐ray diffraction methods have been applied to characterize the state of crystal perfection.
X‐ray study and physico‐chemical analyses of magnesium hexaaquabromate
Authors: Lutoslawska‐Rogóż J. , Kapturkiewicz‐Kowal E. , Hodorowicz S. A. 
Published: January 2007

AbstractMagnesium hexaaquabromate (Mg(H2O)6(BrO3)2) was obtained and analysed by means of X‐ray powder diffraction, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) technique. A thermal analysis of the compound was also carried out. In the temperature range 293–77 K there was no structural phase transition detected. The space group of the compound was found to be Pa3 and the structure of the magnesium hexaaquabromate was refined using the Rietveld method.
Relationship between refractive index, optical electronegativities and electronic polarizability in alkali halides, III–V, II–VI group semiconductors
Authors: Reddy Dr. R. R. , Nazeer Ahammed Y. 
Published: January 2007

AbstractRefractive indices have been evaluated from DUFFY'S optical electronegativities. The validity of the proposed empirical relation has been tested in the case of II–Vi, III–V compound semiconductors and alkali halides by comparing the calculated values of n with those in the literature. The estimated refractive indices are used in Classius‐Mossotti relation to evaluate electronic polarizabilities in the above compounds. The nature of the bonding in terms of Δχ and n is discussed. Good agreement is observed between the computed and literature values of electronic polarizability.
Growth and Kinetic Measurements of Triglycine Sulphate Crystals
Authors: Alexandru H. V. , Berbecaru C. 
Published: January 2007

AbstractSynthesis and two‐step recrystallisation have been used to produce TGS basic substance. Kinetic measurements have been performed for (110)‐type face on a large scale of supersaturations up to about 3%. Evidences of impurity influence for small supersaturation and the “coverage” effect has been estimated.
Deposition Efficiency Reducing Reactions in Silicon Deposition from Silane at Low Pressure
Authors: Kühne H. 
Published: January 2007

AbstractSilane pyrolysis at polysilicon low‐pressure‐deposition conditions is analyzed along the reactor‐tube axis with respect to the existence of competing decomposition reactions leading to the formation of silicon‐containing gaseous byproducts. The presence of such a parallel reaction is indicated by a difference between silane decomposition efficiency ηSiH4 and silicon deposition efficiency ηsi. The rate of such a competing parallel reaction is influenced by the variation of deposition temperature and/or substrate area of silicon deposition. It is drastically accellerated by the presence of phosphine in the gas phase. For the latter case the competing parallel reaction is shown to occur as a homogeneous reaction.
The Infra‐red and Raman Spectra of the Solid Solutions in the KNO3–NH4NO3–H2O System at 298 K
Authors: Dejewska B. 
Published: January 2007

AbstractThe infra‐red and Raman spectra of the solid solutions forming in the KNO3–NH4NO3–H2O system have been made. The spectra have been in agreement with the structure of mixed crystals settled previously.
Effect of Terminal Groups on Formation of Crystal Structure in α,γ‐Disubstituted n‐Alkanes
Authors: Kobayashi H. , Yamamoto T. , Nakamura N. 
Published: January 2007

AbstractThe crystal and molecular structure of 1,16‐dibromohexadecane have been determined by X‐ray diffraction. Crystal data; empirical formula, C16H32Br2, formula weight Mr = 384.24, monoclinic, P21/a, a = 31.00(2), b = 5.38(1), c = 5.48(1) Å, β = 90.8(2)°, V = 914(3) Å3, Z = 2, Dx = 1.396 g/cm3, δ(CuKα) = 1.5418 Å, μ(CuKα) = 55.41 cm−1, F(000) = 396.00, T = 293 ± 1 K, wR = 0.082, R = 0.054 for 940 unique reflections [I > 3.00σ(I)]. The molecular skeleton has an all trans zigzag hydrocarbon chain. The crystal has a layer structure, but the directions of molecular axes in neighbouring layers alternate. This molecular packing resembles to that of 1,16‐hexadecanediol, whereas n‐alkanes or α‐monosubstituted n‐alkanes do not appreciably have these molecular arrangement. The effect of terminal groups at both ends of α,ω‐disubstituted n‐alkanes on the crystal structure is discussed.
Analysis of the Diametral Response of a Czochralski Crystal (III) Solution of the Equation Set. Transfer Functions
Authors: Sveshtarov P. , Gospodinov M. 
Published: January 2007

AbstractThe paper is the third in a series which presents results on the small‐signal diametral response of a Czochralski crystal grown in a resistively heated furnace to variations in heater temperature and pull rate. For typical growth conditions and a wide range of materials it has been shown that this response is obtained by solving a set of linear differential equations. Conditions for normal response, i.e. the diameter increasing on heater temperature and/or pull rate decrease, have been established and shown to hold for most practical cases. The transfer function obtained is consistent with previous results for an inductively heated growth apparatus.
Microhardness Studies of Pure and Doped Crystals of Lead(II)Chloride and Lead(II)Bromide
Authors: Sagayaraj P. , Sivanesan S. , Gobinathan R. 
Published: January 2007

AbstractSingle crystals of pure and monovalent metallic ion doped (K+, Na+, Cu+, Ag+, and Hg+) lead(II)chloride and lead(II)bromide were grown using silica gel. The growth experiments have been carried out by employing a modified two‐stage chemical reaction. The grown crystals of pure and doped lead(II)chloride and lead(II)bromide are subjected to microhardness studies. The validity of Kick's relation is checked. The value of standard hardness number Hv and the work hardening coefficient n are found out. The influence of the presence of the added dopant on the microhardness behaviour of the crystal is studied. A possible relation between the hardness value Hv and the ionic radii of the added dopants is established and the results are discussed.
Electrical Properties of Praseodymium‐doped GaAs and Al0.3Ga0.7As Epilayers
Authors: Lai M. Z. , Chang L. B. , Chen C. C. , Wang H. T. , Jiang G. C. 
Published: January 2007

AbstractPraseodymium‐doped GaAs and Al0.3Ga0.7As epilayers grown on Semi‐Insulating (SI) GaAs substrates by Liquid Phase Epitaxy (LPE) were first studied in this present work. Measurement techniques, such as microscopic observation, X‐ray diffraction, Secondary Ion Mass Spectroscopy (SIMS), and Hall measurement were employed. Layers doped with Pr resulted in a mirror‐like surface, except several high Pr‐doped layers having droplet surfaces. Hall measurements reveal that the grown layers contained p‐type layers, carrier concentrations from 6.3 × 1015 to 1.2 × 1016 cm−3, and from 6.3 × 1015 to 3.5 × 1016 cm−3 for Pr‐doped GaAs and Al0.3Ga0.7As epilayers, respectively. Although p‐type conduction exists, in the light of electrical features, doping of Pr into the GaAs and Al0.3Ga0.7As growth melts, is still considered to exhibit gettering properties rather than to become a new acceptor itself. Additional photoluminescence examinations were taken. Their results also indicate that Pr‐doped layers produce no new emission lines and support the electrical observations.
The Ostwald Rule of Stages
Authors: Nývlt Jaroslav 
Published: January 2007

AbstractCrystallization from solutions often starts in such a way that thermodynamically unstable phases appear first followed by recrystallization to thermodynamically stable phases. This empirical observation, called as Ostwald's rule of stages, is explamed here on the basis of structure changes of solutions. Experiments supporting this explanation have been carried out with aqueous solutions of citric acid, sodium hydrogen phosphate and ferrous sulphate, respectively.
Growth Processes and Properties of Fe‐ and Co Electrodeposited Alumite Films
Authors: Shadrow V. G. , Boltushkin A. V. , Tkachenko T. M. , Semeshko A. V. , Komarovskaya Y. D. 
Published: January 2007

AbstractGrowth processes, structure and properties of Fe, Co, FeCo deposited alumite films have been investigated. It is shown that the magnetic characteristics depends both on alumite film parameters and properties of deposited metal (alloy) particles.
Working Model for Explanation of Polytype formation Based on Superlattice Ordering of Point Defects in Close Packing Structures
Authors: Kozielski M. J. , Tomaszewicz A. 
Published: January 2007

AbstractThe model is an attempt to give an explanation of polytype orderings in the crystals. Basic assumptions of the model are: the point defects play the important part in the polytype formation; these defects influence the configuration (hexagonal or cubic) of individual layers. The defects have a tendency to ordering themselves into superlattices. It acts selectively on particular stacking of the layer sequences. The results of model operation are shown in examples of experimental data of polytypic materials; they are SiC and AIIBVI compounds.
The Microcamera Used for Photoelectron Excited by the X‐ray Standing Wave (XSW) Recording and Submicron Layer Structure Studies
Authors: Auleytner J. , Godwod K. , Pelka J. 
Published: January 2007

AbstractInformation obtained owing to aquaintance with the course of the angular dependence of photoelectron intensity excited by the X‐ray standing waves allows to determine, more explicitly, the state of crystal surface layer deformation. The aim of this work is to present a new measuring device constructed at the Institute of Physics of the Polish Academy of Sciences, especially the X‐ray microcamera being simultaneously the proportional flowing counter used for measuring of photoelectron current emitted from the examined crystal. The angular dependence of the photoelectron current can be measured in coincidence with the angular running of rocking‐curves. It is possible due to a computer program controlling the X‐ray doble‐crystal spectrometer, the microcamera and the electronic system for registration of the intensity of the diffracted beam as well the flowing counter.The scheme of the X‐ray double‐crystal spectrometer, the microcamera, and the electronic measuring system operation is given. There are also given the results of the introductory measurements carried out for the Si(111) implanted with the Au ions. The calculation of rocking‐curve for non‐disturbed crystal in the case of asymmetrically cut monochromator crystal was made. There was also estimated the range of depth from that the photoelectrons were emitted.
Influence of F‐Anions on the Habit and Growth Mechanism of Potassium‐rich Feldspars
Authors: Franke Walter A. , Słaby Ewa 
Published: January 2007

AbstractOrthoclase‐rich alkalic feldspar crystals were grown from melts next to Orthoclase‐Albite‐Quartz eutectic composition at 2 kb in the presence of a surplus of a supercritical aqueous phase by isobaric cooling at a rate of approximately 10 °C/day. Some runs were made with KF‐bearing fluid phase, in two runs the melt was formed during intensive thermoconvection of the fluid phase. Tabular crystals were only formed from F‐bearing melts, crystals grown from F‐free melt were always fan‐shaped. We assume this fact is due to a more easy supply of Al to the growing crystal in melts with F content.
Phase Transition of 1,16‐Hexadecanediol
Authors: Kobayashi H. , Nakamura N. 
Published: January 2007

AbstractIt was found that 1,16‐hexadecanediol exhibited a solid‐solid phase transition. X‐ray diffraction experiments and dielectric constant measurements were carried out in order to investigate the structure of the high‐temperature phase. A model of molecular arrangement in the high‐temperature phase was presented. The high‐dielectric constant values were observed in the high‐temperature phase. It is considered that the high‐temperature phase of 1,16‐hexadecanediol is a rotator phase in analogy with n‐higher alcohols.