bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Crystal Structure of Na‐Sulfadimidine
Authors: Patel Dr. Urmila H. 
Published: January 2007

AbstractThe X‐ray crystal structure analysis of Na‐sulfadimidine is reported. Crystals are triclinic. Space group P1 with a = 5.785(2), b = 11.568(1), c = 12.722(2) Å, α = 70.02(1), β = 78.71(2), γ = 77.73(2)° and Z = 2. Crystal structure was solved by direct method to an R‐value of 0.061 for 2441 unique reflections. It is a type of five‐fold coordination complex of Na where Na atom is surrounded by four oxygen atoms and one nitrogen atom: three oxygen atoms and the nitrogen atom belongs to the sulfonyl moiety from three different sulfadimidine molecules and the fourth oxygen atom belongs to solvent water molecule. The crystal structure is stabilized by hydrogen bonds and van der Waals forces.
Effect of Lithium Doping in the Bi‐2212 Superconducting System
Authors: Gopalakrishna B. , Chandra Sekhar M. , Suryanarayana S. V. 
Published: January 2007

AbstractSamples with the nominal composition Bi2Sr2Ca1–xLixCu2Oy (x = 0.2,0.4, and 0.6) and Bi2Sr2CaCu2−x L1xOz (x = 0.4, 0.6, and 1.0) were prepared by the solid state reaction method. The role of L1 at both Ca and Cu sites in the Bi‐2212 composition were studied. From the X‐ray diffraction data it was found that the L1‐doped at the Ca site increases the c‐axis and that doped at the Cu site decreases the c‐axis. From the D.C. four‐probe resistivity data it was found that Li‐doped at the Ca site reduces the Tc and the L1‐doped at the Cu site gives Tc(0) above the liquid nitrogen temperature. It was observed that the L1 doping reduces the melting point of Bi‐2212 composition. The presence of Lithium was confirmed by inductive the coupled plasma method.
Orthorhombic Polymorph of ErP5O14, Crystal Structure and Characterization
Authors: Katrusiak Andrzej , Kaczmarek Franciszek 
Published: January 2007

AbstractErbium pentaphosphate crystals have been characterized and the structure of the orthorhombic polymorph (type III) determined by X‐rays. It has been found that the orthorhombic samples of ErP5O14, space group Pnma, crystallize mainly at higher temperatures and usually are much larger than monoclinic crystals, space group C2/c, obtained from lower‐temperature crystallizations. Differences in fluorescence and upconversion properties between orthorhombic and monoclinic polymorphs have been detected.
Crystal and Molecular Structure of Tosyl Pyrrolidine‐2‐Methanol (C12H17SO3N)
Authors: Sambyal Vinod Singh , Padha Naresh , Goswami K. N. , Bhutani K. K. , Gupta D. K. 
Published: January 2007

AbstractC12H17SO3N, Mr = 255.33, Orthorhombic, P212121, a = 11.703(1) Å, b = 14.797(3) Å, c = 14.971(2) Å, V = 2592.52 Å3, Z = 8, Dm = 1.309 Mgm−3, Dc = 1.308 Mgm−3, mμ = 21.57 cm−1, F(000) = 1088, T = 290 K, final R = 0.080 for 2416 unique reflections. There are two crystallographically independent molecules in the unit cell of the title compound.
On the Reasons Leading to an Appearance of Correlated and Anticorrelated Dependences of the Minority Carrier Lifetime on the Dislocation Density in Undoped Semi‐Insulating “Stoichiometric” GaAs Crystals
Authors: Glinchuk K. D. , Prokhorovich A. V. 
Published: January 2007

AbstractIt is shown that in undoped semi‐insulating GaAs crystals grown under the stoichiometric conditions both correlated and anticorrelated dependences of the minority carrier lifetime τ on the dislocation density Nd could be observed. The above‐pointed effect is connected with a slight excess of Ga atoms (then the correlated dependence τ vs Nd appears) or of As atoms (then the anticorrelated dependence τ vs Nd appears) which inevitably exists even in “stoichiometric” GaAs crystals (i.e. in GaAs crystals of “stoichiometric” composition).
The Crystal and Molecular Structure of Mesomorphic 1,4‐Dipentadecanoyloxy‐biphenyl (SYM‐14)
Authors: Thyen W. , Kaiser V. , Zugenmaier P. 
Published: January 2007

AbstractThe compound with the general formula CnH2n+1 –COO–C6H4–C6H4–OOC–CnH2n+1, n = 14 (SYM‐ 14) crystallizes in the triclinic space group P 1, with a = 5.431(5), b = 9.346(8), c = 39.172(51) Å, α = 92.60(15), β = 90.65(15), γ = 100.364(8)°.The crystal structure was solved by direct methods. Least‐squares refinement leads to a final R value of 0.092 for 1575 observed reflections, with I > 2σs(I). The packing arrangement follows the same building principles found recently for the first three members of the well known homologous series of liquid crystalline terephthalylidine‐anilines (TBAA‐n).
Synthesis and Characterisation of Bulk Textured Phases in the Bi(Pb)—Sr—Ca—Cu—O System
Authors: Murugakoothan P. , Jayavel R. , Subramanian C. 
Published: January 2007

AbstractGrowth of lead‐doped textured Bi‐cuprate, using an immersed heater floating zone (TSFZ) apparatus, from a narrow supercooled melt created an essentially dense structure consisting of locally aligned long platelet crystal grains. The extended grains have their long axes parallel to the growth axis with a low angle misorientation. The effect of gas bubbles and the pulling rates on the microstructure and superconducting transition temperature of the textured boules have been studied. The decomposing nature of the 2223 phase on melting leads to form the energetically favourable low Tc 2212 phase.
High Quality InAs1–ySby/InAs Multilayers for mid‐IR Detectors
Authors: Gong X. Y. , Kan H. , Makino T. , Yamaguchi T. , Nakatskasa T. , Kumagawa M. , Rowell N. L. , Wang A. , Rinfret R. 
Published: January 2007

AbstractThe high quality InAsSb multi‐layers have been grown on InAs substrate by Gd‐doped liquid phase epitaxy between 530 and 460°C. Compositional dependence of energy band gap and of lattice constant for epilayers were studied. The material is characterized by surface morphology observation, FTIR transmittance, photoluminescence (PL), spectro‐ellipsometry, and electrical measurements. Surface‐illuminated room temperature p‐n junction photodetectors in 3–5 μm wavelength range have been obtained.
Refined Crystal and Molecular Structure of Andrographolide — Diterpene
Authors: Sambyal Vinod Singh , Goswami K. N. 
Published: January 2007

AbstractA refined crystal structure of andrographolide has been obtained by X‐ray anaysis using CuKα radiation. It crystallizes in the monoclinic crystal system with unique b‐axis in space group P21. The unit cell parameters are a = 6.552(2) Å, b = 8.009(1) Å, c = 17.989(1) Å and interaxial angle β = 97.32(1)°. The structure has been solved by direct methods and was refined up to R = 0.041, ωR = 0.0464. Both the cyclohexane rings are in chair conformation with the furan ring in twist conformation. The crystal structure is stabilized by hydrogen bonding.
X‐ray Monitoring System for in situ Investigation of Thin Film Growth
Authors: Mikhailov I. F. , Pinegin V. I. , Sleptzov V. V. , Baranov A. M. 
Published: January 2007

AbstractThe X‐ray optical system of in situ monitoring of reflectivity measured in the short‐wave range 0.5–3 Å is proposed. Thickness, density, and microroughness of the growing film are determined for every half‐wave of reflectivity oscillations that corresponds to the averaging by the layer of 10 Å thickness. By the example of diamond‐like film growing, the possibility of an analysis of transition processes and technology failure during film growth have been shown.
Thermodynamic Analysis of Urea Physical Vapour Transport
Authors: Paorici C. , Zha M. , Zanotti L. , Attolini G. , Traldi P. , Catinella S. 
Published: January 2007

AbstractThe vaporisation‐condensation scheme of urea has been investigated in the temperature region below the melting point, in order to establish the thermodynamic reactions on which the physical vapour transport (PVT) of urea is based. By making use of both reported data and experimental results of MS, DTA, DTG, and HPLC analysis, it was shown that PVT relevant reactions are basically molecular sublimation and partial decomposition in solid biuret and ammonia. MS analysis of urea crystals and source residues have also shown that no decomposition can be observed in the growing crystals, unless reheated during growth.The temperature dependence of the decomposition pressure has been found to be: log10PNH3 [torr] = 38 – 13840/T [K].The use of this relation in diffusive mass transport calculations brought to linear growth rate values not in disagreement with the experimental values found in closed tube PVT grown crystals.
Electrical Conductivity and Thermoelectric Power of Silver Iododichromate Fast Ion Conducting Electrolytes
Authors: Durga Rani A. N. , Hariharan Dr. K. 
Published: January 2007

AbstractFast ion conducting solid electrolytes are becoming increasingly important owing to their application in solid state ionic devices. The present work deals with the silver ion conducting x AgI – (1–x)Ag2Cr2O7 electrolyte system. These electrolytes have been characterised by X‐ray diffraction, electrical conductivity, electronic conductivity and thermoelectric power techniques. A high ionic conductivity of the order of 10−3 S/cm has been observed for the composition mol% 80 AgI–20 Ag2Cr2O7, at room temperature. The electronic conductivity of this electrolyte is three orders of magnitude lower than the ionic conductivity.
Electrical Conductivity and Thermal Dehydration Studies of Mixed Single Crystals of BaCu(C2O4)2 · 6 H2O, Ba1–xCuxC2O4 · 4 H2O and Ba1–2x(NH4)2xC2O4 · 4 H2O
Authors: Kasthuri V. B. , Mohan Rao P. 
Published: January 2007

AbstractThe measurement of electrical conductivity for the investigation of the number of water molecules present in the mixed crystals of barium copper oxalate and barium ammonium oxalate lattice have been carried out in the temperature range 30 to 450 °C. The dehydration temperature and the number of water molecules removed out of the structure at a particular temperature is estimated from the sharp increase in conductivity at these points. The almost steep increase of conductivity is attributed to the increase in the number of mobile charge carriers H+ and OH– ions generated from the escaping water molecules.The study of electrical conductivity in association with the thermal behaviour has been used to understand the mechanism of conduction.
Precipitation of Catalyst Precursors Theoretical Fundamentals
Authors: Nvlt J. 
Published: January 2007

AbstractVery high supersaturations, low stability of highly supersaturated solutions, marked secondary changes in the solid phase formed, chemical changes during the ageing of precipitates — this are reasons why our contemporary knowledge on precipitation is far more limited and is also inconsistent compared with mass crystallization of readily soluble substances. In view of this situation, it seems to be highly desirable to show the general fundamentals which could lead us to systematic understanding of the various cases apparently unrelated with each other.
An Exponential‐Hyperbolic Crystal Growth Rate Model
Authors: Mydlarz Jerzy 
Published: January 2007

AbstractA new exponential‐hyperbolic size‐dependent crystal growth rate function G (L) = Gm (eaL–b)/(eaL – c) is proposed. The model has been examined in detail for the direct determination of size‐dependent crystal growth rates from the cumulative number oversize distribution of continuous Mixed‐Suspension Mixed‐Product Removal (MSMPR) crystallizers using both simulated and realistic data, both for systems that hold and that violate McCabe's Δ law, respectively. It is show that direct fitting of cumulative number oversize distribution data using the proposed model gives an improved estimation of effective crystal growth rates over the whole size range during MSMPR crystallization compared with previous models tested.
Neutron and Synchrotron Radiation High Pressure Experiments on Aluminate Sodalite Sr8[Al12O24](CrO4)2
Authors: Melzer R. , Depmeier W. , Vogt T. , Gering E. 
Published: January 2007

AbstractHigh pressure powder diffraction experiments were carried out on the aluminate sodalite Sr8[Al12O24] · (CrO4)2 using a miniature clamped cell with neutron radiation at the ILL and a diamond anvil cell with synchrotron radiation at Hasylab/Desy. The results of both experiments agree well. Lattice parameters were determined up to a pressure of 7.2 GPa. The average linear compressibility amounts to 4.3 · 10−3 GPa−1, which corresponds to a linear bulk modulus of 233 GPa. The observation of superstructure reflections could be related to two new phase transitions. The first one occurs between 0.37 and 0.5 GPa, the second one at about 2.0 GPa. A final measurement at ambient pressure revealed the reversible character of the pressure induced phase transitions.
A New Modified TGS Crystal
Authors: Fang C. S. , Liu H. , Zhuo H. S. , Wang M. , Xu D. 
Published: January 2007

AbstractTriglycine sulfate (TGS) crystals doped with Cr6+ have been grown from a growth solution with various Cr6+ concentrations. The structure, transmission spectrum, pyroelectric properties, and the photorefractive effect of the crystals have been measured. It has a high internal bias field and photorefractive effect.
SEM Observation of Nucleation and Growth of Ag Crystallites on Graphite Substrate
Authors: Gotoh Yoshihiko , Horii Akira , Ishii Toshio , Kawanowa Hitoshi , Yumoto Hisami , Gonda Takehiko 
Published: January 2007

Abstract“In‐Situ” observation of nucleation and growth of Ag crystallites on graphite substrate by vapour deposition was carried out by scanning electron microscope (SEM). Irradiation of the SEM electron beam onto the substrate surface before and during deposition enhanced Ag nucleation. The density of the Ag crystallites was 1010/cm2 in room temperature condensation, but decreased to 109/cm2 in high temperature condensation at 140 °C. When the substrate was heated after room temperature condensation, the density of the Ag crystallites decreased prominently. This means that coalescence of the Ag crystallites takes place as a result of their migration on the substrate.
Crystal Structure of a Complex of Sarcosine with Barium Chloride
Authors: Krishnakumar R. V. , Natarajan S. 
Published: January 2007

AbstractSingle crystals of sarcosine barium chloride tetrahydrate were crystallised from a saturated aqueous solution containing stoichiometric amounts of sarcosine and barium chloride, in 2: 1 proportion. The intensity data were collected using a CAD‐4 diffractometer with graphite monochromated MoKα radiation. The crystal data are as follows: a = 7.235(1) Å, b = 10.668(4) Å, c = 15.686(3) Å, V = 1210.7 Å3, F.W. = 369.33, dexpt, = 2.02 g · cm−3, dcalc = 2.026 g · cm−3, Z = 4 and the space group is P212121. The structure has been solved to an R value of 0.02 for all the 1239 reflections with I > 2σ(I). The sarcosine molecule exists as zwitterion in the structure. The barium ion is found to have 10‐fold coordination with nine oxygens and a chlorine taking part in coordination. All the water oxygens and chlorines take part in hydrogen bonds except carboxyl oxygens.
Pressure Dependence of C–V Curve for Ferroelectric PbTiO3 Thin Films Prepared by RF Multi‐target Magnetron Sputtering
Authors: Cho C. R. , Jang M. S. , Jeong S. Y. 
Published: January 2007

AbstractLead titanate thin films were prepared in‐situ by RF magnetron sputtering method in the substrate temperature region of 550 °C ˜ 650 °C using Ti and Pb metal targets and oxygen gas. The films deposited at 650 °C for 60 min – when the applied power to the Ti and Pb target and deposition pressure were 200 W, 40 W, and 1.8 × 10−2 Torr, respectively — had stoichiometric composition ratio and shown X‐ray diffraction patterns of tetragonal structure like that of the powder.For the application to the piezoelectric field effect transistor (PI‐FET), the substrate of SiO2 (50 nm)/p‐Si(100) was used. Leakage current density of the thin film was 7 × 10−8 A/cm2 at 100 kV/cm, dielectric breakdown voltage was 1.8 MV/cm, and so it showed high insulator characteristics. Capacitance‐voltage curve was measured as a function of pressure. The variation width of the capacitance was 6.5 pF at bias voltage of –4 volts, and the value increased linearly according to the pressure up to about 6 kgf/cm2, and was saturated at the pressure of 8 kgf/cm2.
Crystallization Kinetics of Sodium Perborate
Authors: Livk Ing.I. , Smodiš Ing.M. , Golob Prof. Dr. Ing.J. , Pohar Prof. Dr. Ing. sc.C. 
Published: January 2007

AbstractSome basic physicochemical properties of aqueous sodium perborate solutions, essential in designing an effective control, were measured. The kinetics of primary nucleation was determined by the measurement of the metastable zone width. The differential method was applied for the determination of the crystal growth rate equation. It was found that the solubility and the nucleation rate constants are in very good agreement with the literature data whereas the parameters of the growth rate equation show an influence of the experimental conditions.
Temperature Oscillations in Eutectic Alloy Melt for the Bridgman‐Stockbarger Configuration
Authors: Pražák M. , Holeček S. 
Published: January 2007

AbstractThe characteristics of the temperature field in AlZn, AlGe, PbSn, and Sb—InSb low‐melting alloy eutectics were determined by means of the Bridgman‐Stockbarger method of directional solidification with a specimen fixed in a graphite ampoule and a moving furnace. The device could be rotated in such a way, that an arbitrary angle α between the axial temperature gradient in the melt and the gravity field vector could be set.Periodic and/or nonperiodic temperature fluctuations indicating periodic and/or nonperiodic turbulent convection up to an angle α = 80° were studied in the individual systems. At larger angles laminar convection can be expected. The frequency of the temperature oscillations is the same along the entire length of the specimen, whilst the amplitudes of the temperature oscillations depend on the situation of the measurement in the specimen.It has been found that the zone of unstable periodic convection is reduced with an increase of the axial temperature gradient and a decrease of the H/d ratio for a cylindrical ampoule. The convection instability threshold in the ampoule increases with the deviation of the ampoule axis from the axis of the vertical unstable arrangement, i.e. from the direction of the gravity vector. The threshold of the laminar flow instability and the onset of turbulent flow increases with the H/d ratio, i.e. an ampoule with a higher H/d ratio stabilizes laminar flow.
Structural Studies of Some Zinc‐ and Calcium Sulfide Phosphors
Authors: Sen D. K. , Bhushan S. 
Published: January 2007

AbstractThe XRD studies of CaS : Cu,Cl; ZnS · Cu,Cl; (Zn + Ca) S : Cu,Cl, and (Zn + Ca) S · Cu, La,Cl showed the presence of materials like CaSO4 and ZnO. However, the explanations given earlier (SEN, BHUSHAN) on the origin of different bands observed in the electroluminescence spectra of these materials remain valid.
Chiral Symmetry Breaking in Sodium Chlorate Crystallization from Unstirred Solution
Authors: Szurgot Marian , Szurgot Jadwiga 
Published: January 2007

AbstractStatistics of nucleation of chiral forms of sodium chlorate from unstirred, achiral solutions was studied. The trimodal distribution of enantiomers was obtained in which apart from the peak for the same probability of the creation of L and D crystals, two other maxima for the large enantiomeric excesses of L and D forms were present. The first nucleated crystals govern the handedness of the secondary crystals and the formation of pure enantiomers and high enantiomeric excesses in crystallization from unstirred, unseeded solutions are caused by the process of chiral symmetry breaking rather than statistical fluctuations.
On the Diffusion Anisotropy of Polycrystals
Authors: Divinski S. V. , Larikov L. N. 
Published: January 2007

AbstractA model of diffusion anisotropy appearance in a textured polycrystalline aggregate under the grain boundary diffusion preponderance (the C type of kinetic) has been suggested. Although in the textured polycrystal there exists a distribution over 5 degrees of freedom describing the grain boundaries macroscopically, it is the misorientation distribution that has been shown to may give rise to the diffusion anisotropy. Presence of small‐angle boundaries and a certain, sufficiently sharp texture is the key moment at this.
Forced Electrostrictive Vibrations of Cubic Crystals
Authors: Kloos G. 
Published: January 2007

AbstractA problem of experimental research in quadratic electrostriction is the question how the observed strain signal, induced by a high electric field, is influenced by sample mounting. An analytical treatment of the case of a cubic crystal is demonstrated that allows one to find a relationship with material constants and strains that may occur at the bottom of the sample. To find functions that fulfill the given boundary conditions an approach similar to that used to solve the problem of the elastic cube with Somigliana boundary conditions has been employed.
Formation of Three‐dimensional Microelectronic Structures by Molecular Beam Eitaxy Combined with Ion Beam Procedures
Authors: Thomas A. , Ramirez A. , Zehe A. , Brückner V. 
Published: January 2007

AbstractThe progress in microelectronics is characterized by an increasing density of functional elements on the wafer. This is first of all a result of a reduction of lateral dimensions in patterned geometries. Nevertheless, further progress on this way is limited by a number of reasons, e.g. residual impurities in the ingot materials, physical phenomena, as diffusion processes between adjacent layers as well as electron migration inside electronical structures. Finally, the lithographic means of structuring implies disadvantages which limit the minimization progress.One way to overcome these problems consists in three dimensional structuring of microelectronical objects. Thereby, the third dimension is introduced by growing of thin layers which are again structured in their lateral dimension. This can be done by molecular beam epitaxy (MBE) in combination with Ion Beam (IB) procedures.The present paper gives an overview on materials which exhibit epitaxial growth on Si. The utility of CaF2 for three dimensional structuring by use of ion bombardment will be described. As another example, the conversion of materials will be discussed. For instance, insulating CaF2 can be converted into conductive CaSi2 by help of Si+‐ion implantation.
X‐ray Structure Analysis of 4–[(3,3–Dimethyloxiranyl)–methoxy]‐7H‐furo[3,2‐g][1]benzopyran‐7‐one
Authors: Singh Attar , Gupta Vivek K. , Rajnikant  , Goswami K. N. 
Published: January 2007

AbstractThe title compound, C16H14O5, a furanocoumarin crystallizes in the triclinic space group P1. The unit cell parameters are a = 7.852(2), b = 8.485(1), c = 11.095(1) Å; α = 105.90(1), β = 103.18(2), γ = 95.07(1)°. The structure has been solved by direct methods. Final R = 0.048 for 1943 observed reflections. The furanocoumarin system is almost planar. The epoxide ring makes a dihedral angle with the fused ring system of 98.21(11)°. Molecules are held together by C—H… O hydrogen bonds.
DTA, DSC, and X‐ray Powder Diffraction Studies on Some Zinc Selenate Hydrates
Authors: Koleva V. , Stoilova D. 
Published: January 2007

AbstractThe thermal dehydration of ZnSeO4 · 6 H2O, ZnSeO4 · 5 H2O, and ZnSeO4 · 3 H2O has been studied by TG, DTA, and DSC‐analyses. It has been established that the dehydration of ZnSeO4 · 6 H2O occurs stepwise and as intermidiate hydrates ZnSeO4 · 5 H2O, ZnSeO4 · 3 H2O and ZnSeO4 · H2O are produced. The enthalpy of dehydration of the observed phase transitions has been determined. The enthalpy of formation of ZnSeO4 · 6 H2O, ZnSeO4 · 5 H2O, ZnSeO4 · 3 H2O, and ZnSeO4 · H2O has been calculated on the basis of the DSC‐data. ZnSeO4 · 5 H2O and ZnSeO4 · 3 H2O have been studied rentgenographically: ZnSeO4 · 5 H2O crystallizes in triclinic system with lattice parameters: a = 6.387(2) Å; b = 10.706(3) Å; c = 6.167(3) Å; α = 98.66(2)°; β = 109.32(3)° γ = 75.52(3)° V = 384.3(2) Å3; SG P1. ZnSeO4 · 3 H2O forms orthorhombic crystals with lattice constants: a = 8.165(4)Å; b = 11.314(5) Å; c = 12.465(7) Å; V = 1151.5(7) Å3; SG Pbca.