bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactivity at Line Defects in Antimony in Etchants with Dextro‐ and Levo Tartaric Acid
Authors: Raval Amit H. , Joshi Mihir J. , Shah B. S. 
Published: January 2007

AbstractThe (111) cleavage faces of antimony single crystals were etched in aqueous mixtures of fuming nitric acid plus dextro tartaric acid and fuming nitric acid plus levo tartaric acid. Triangular, crystallographically oriented etch pits were observed at sites of dislocations. The activation energies for lateral motion of ledges and the frequency factors were calculated for both types of etchants which were found to be higher in levo tartaric acid containing etchants than in dextro tartaric acid containing etchants. The results are explained in terms of antimony complexes and the difference in the shape of dextro tartaric acid and levo tartaric acid molecular structures.
Dependence of Transient and Steady State Creep on Grain Size in Aged Al‐10 wt% Zn Alloy
Authors: Youssef S. B. , Beshai M. H. N. , Fawzy A. , Sobhy M. , Saad G. 
Published: January 2007

AbstractThe effect of grain size as well as ageing temperature on the creep characteristics of Al‐10 wt% Zn alloy have been studied. It has been found that the steady state creep rate ε decreases by increasing grain size, whereas it increases by increasing ageing temperature. It is suggested that the decrease of ε may be due to the change in the density of mobile dislocations in addition to the change in concentration of point defects and impurity atmospheres. An empirical formula ε = ml−2 + c has been proposed to correlate the creep rate and grain size. The values of the activation energies controlling the creep processes corresponded to that required for dislocation glide.
Effect of Ultrasonics on Agglomeration
Authors: Nývlt J. , Žáček S. 
Published: January 2007

AbstractCrystal size distribution of potassium aluminium sulphate dodekahydrate prepared under various conditions has been used for characterization of the degree of agglomeration of crystals. Six series of batch precipitation experiments with batch times from 2 to 80 minutes have been represented by a) dried crystals, b) the same crystals partially de‐agglomerated before the measurement, c) wet crystals taken directly from the batch, d) the same crystals partially de‐agglomerated before the measurement, e) wet crystals taken directly from the batch occurring under ultrasonic action, and f) these crystals partially de‐agglomerated just before the measurement. Degree of agglomeration decreases in this sequence.
Size Effect and Processes of Interdiffusion in Multilayer Films
Authors: Protsenko I. , Odnodvoretz L. , Petrenko S. , Chornous A. 
Published: January 2007

AbstractThe electrophysical properties of multilayer structures consisting of the alternate Co and Ni layers or Co and Cr layers obtained in high vacuum (˜ 10−3 Pa) were investigated.The size dependences of the temperature coefficient of the resistance (TCR) of the films were obtained experimentally and then compared with the R. Dimmich theoretical model. The analysis shows that the main reason of the difference between theoretical and experimental data of TCR is the interdiffusion of atoms from one layer to another.
Transition from Isometric to Skeletal Crystal Shapes
Authors: Tonchev V. , Nanev Chr. N. 
Published: January 2007

AbstractThe transition from isometric to skeletal shapes during crystal growth under diffusion hindrances in matter supply has been considered as an orientational phase separation, bringing to energetically more stable surfaces. The critical deviation from the close packed crystallographic orientation and the transition time have been estimated on the basis of a simple model.
Characterisation of the Six‐coordinated Octahedral Site in Cd(C4H2O4) · 2H2O Crystals
Authors: Ravikumar R. V. S. S. N. , Reddy S. N. , Rao S. N. , Reddy B. J. , Reddy Y. P. 
Published: January 2007

AbstractOptical absorption spectra of Co(II) and Ni(II) doped cadmium maleate dihydrate (CMDH) are recorded at room temperature and liquid nitrogen temperature. The UV–VIS–NIR spectra are characteristic of the transition metal ions in solids. The results and analyses of the spectra indicate near octahedral site symmetry for cobalt ion and trigonally distorted octahedral site symmetry for nickel ion. The following crystal field parameters are derived.The IR spectra are characteristic of the host lattice CMDH.
Stacking Fault Energy of Silicon Carbide (SiC) Polytypes
Authors: Momeen  , Khan M. Y. 
Published: January 2007

AbstractA polytypic material grown under similar thermodynamic conditions occurs in several phases which are included as ordered and disordered ones. These phases occur with a minimum free energy difference ≅ kT. This relative free energy (stacking fault energy) has been evaluated here using different methods.
Dilatometric Analysis and HK Hardness Measurement of Directionally Solidified AlZn Eutectic Specimens
Authors: Pražák M. , Holeček S. 
Published: January 2007

AbstractTwo simple and relatively fast methods have been verified of an objective inference of the quality of the directionality of the volume structure of a specimen. The above methods can thus be conveniently added to classical metallography and image analysis.AlZn eutectic appears to be an appropriate model system due to a linear thermal expansion anisotropy of the directionally solidified specimens, which is given by the expansion anisotropy of a directionally positioned β‐Zn phase with a hexagonal lattice. The thermal expansion is lowest in the growth direction of the lamellae.The hardness is anisotropical on the surface. The HK hardness is anisotropical with respect to the position of the indentor in the structure. The hardness shows an overall increase with the growth rate of the specimen (i.e. with the fineness of the structure) and its value its always lowest, when the longer diagonal of the HK indentor is parallel with the lamellae on the cross sections of the specimens.
Long‐term Crystal Growth under Microgravity during the EURECA‐1 Mission (I) THM Growth of AlxGa1−xSb
Authors: Danilewsky A. N. , Lauer S. , Bischopink G. , Benz K. W. 
Published: January 2007

AbstractLong‐term crystal growth experiments were successfully performed under microgravity conditions during the first flight of the unmanned mission EURECA‐1 in the automatic mirror furnace (AMF). Two crystals of AlxGa1−xSb with [001] and [111] orientation respectively were grown from gallium solution by the travelling heater method. The grown length of the single crystals is 4.0 mm and 4.2 mm respectively. The space‐grown samples show a high microscopic homogeneity which indicates the absence of time dependent convection. From pulse markers a constant growth rate of 0.6 ± 0.1 μm/min is measured which is lower than 0.8 ± 0.1 μm/min obtained in earth grown reference samples. Details about the experiment performance and the growth results are given.
The Effect of Different Inorganic Salts on the Growth Rate of NaCl Crystallized from Sea Water
Authors: Zhang S.‐B. , Yuan J.‐J. , Mohameed H. A. , Ulrich J. 
Published: January 2007

AbstractA comprehensive experimental study on the effect of fourteen different inorganic salts on the growth rate of NaCl single crystals is presented. The fourteen different inorganic salts are chosen as they are present in Chinese sea water. The impurity content of each salt has been varied according to its presence in the natural sea water. The impurities are differentiated in groups related to their effect on the growth rate of NaCl. The examined impurities are: MgCl2 · 6 H2O, KCl, SrCl2, NaBr, Nal, NaF, Na2SO4, NaBO2 · 4 H2O, Na2CO3, Na2SiO3 · 9 H2O, ZnSO4, CuSO4 · 5 H2O, PbCl2, and K4Fe(CN)6.
Crystal Structure of 6,6′‐dimethoxy‐2,2′‐diphenyl‐19‐crown‐5 Hg(SCN)2
Authors: Ochando L. E. , Amigo J. M. , Costero A. M. , Pitarch M. , Debaerdemaeker T. 
Published: January 2007

AbstractThe crystal structure of 6,6′‐dimethoxy‐2,2′‐diphenyl‐19‐crown‐5 Hg(SCN)2 has been determined from three‐dimensional X‐ray diffraction data. The compound crystallizes in the triclinic space group P1 (no 2) with unit cell parameters α = 9.712(6) Å, β = 11.137(7) Å, c = 14.768(12) Å, α = 86.04(5), β = 80.36(4), γ = 65.70(4), Z = 2, V= 1435(2) Å3. The structure was determined by direct methods which on refinement yielded a final value of R(F) index as 0.068.
Twinning of Crystals due to Differences between the Most Favourable Symmetric and Energetic Structural Arrangements, Part II
Authors: Krafczyk S. , Jacobi H. , Follner H. 
Published: January 2007

AbstractTwins and oriented intergrowths are often caused by structural instabilities. A conflict arises between the highest symmetric and the most favourable energetic structural arrangement. A necessary condition for twin growth is the presence of lattice pseudosymmetries. This was shown with two additional examples, maleic acid and 3,5‐dimethylbenzoic acid. Both substances are known practically only as twins. Using lattice‐energy calculations, energetic arrangements that are more favourable were found in both cases. These structures explain the transition that can exist between the twin crystal parts.
The Thermal Decomposition of Polyhalite K2SO4 · MgSO4 · 2 CaSO4 · 2 H2O
Authors: Fischer S. , Voigt W. , Köhnke K. 
Published: January 2007

AbstractThe thermal decomposition of polyhalite (K2SO4 · MgSO4 · 2 CaSO4 · 2H2O) was investigated by DSC/TG and X‐ray powder diffraction. The decomposition of the polyhalite starts at 285 °C in releasing the crystal water within one step. Simultaneously the decomposition of the polyhalite into anhydrite and two solid solutions of the compositions K2SO4 · 1.76 MgSO4 · 0.24 CaSO4 and K2SO4 · 0.64 MgSO4 · 1.36 CaSO4 is taking place. The mechanism of decomposition runs through K2SO4 · MgSO4 CaSO4. This phase reacts immediately to the solid solutions, mentioned above.
The Double Salts Cd(C6H5COO)2 · CdCl2 and Cd(C6H5COO)2 · CdBr2
Authors: Balarew Christo , Stefanova Rumiana 
Published: January 2007

AbstractThe systems Cd(C6H5COO)2CdCl2H2O and Cd(C6H5COO) 2CdBr2H2O have been studied at 25 °C. Formation of the double salts Cd(C6H5COO)2 · CdCl2 and Cd(C6H5COO)2 · CdBr2(1:1:0) has been established and their chemical individuality has been confirmed by chemical, X‐ray, and DT‐analyses.Proceeding from data on the structure of Cd(C6H5COO)2 · 2 H2O and the composition of the 1:1:0 double salts as well as using Pauling's rules for the most probable spacial disposition of the ions, the crystal structure type of the double salts obtained are predicted.
Diamond Synthesis by Thermal Plasma Chemical Vapour Deposition (TP‐CVD)
Authors: Presia M. , Heider Th. , Schleicher L. , Nutsch G. 
Published: January 2007

AbstractThis paper reviews results about diamond synthesis by high‐temperature pyrolysis of methane in a H2/Ar‐plasma. By means of a modified direct‐current (DC) plasma torch with an arc power of 4–8 kW diamond growth rates in the order of about 70 μm/h were obtained. Diamond films grown on unscrached single‐crystalline silicon have a diameter of about 8 mm. Scanning electron microscopy (SEM), X‐ray diffractometry (XRD), and Raman scattering spectroscopy have been used to analyse diamond films characterized by a transition of a crystalline diamond centre to an amorphous random region by passing a fine‐crystalline region. In the film centre (100) planes with an average size of about 25 μm were made out by SEM.
In Situ Observation of Step Evolution on {100} Face of KH2PO4 Crystal in Solution by Atomic Force Microscopy (AFM)
Authors: Krasiński Mariusz J. , Rolandi Ranieri 
Published: January 2007

AbstractIn situ observation of the surface morphology of {100} face of Potassium Dihydrogen Phosphate (KDP) crystals growing in solution was made with the use of Atomic Force Microscope. The slight movement of the steps connected with regeneration of the crystal surface has been detected for very low supersaturation. The height of the elementary steps has been established.
Observation of Ferromagnetic Domains in NdFeB Single Crystals by Photoelectron Microscopy
Authors: Wang J. Y. , Romanowicz J. , Maundschau M. , Sun D. L. , Chen H. C. 
Published: January 2007

AbstractThis paper reports on the successful growth of NdFeB single crystals. Ferromagnetic domains of these crystals are observed by photoelectron microscopy. Thc domains may disappear and re‐appear during the experiments. A possible mechanism of the contrast formation of the domains is proposed and discussed.
Alkali Defect Centers and Current Density Peaks in Quartz Sweeping
Authors: Iliescu B. , Vedda A. , Spinolo G. 
Published: January 2007

AbstractThe paper presents the current density peaks during the heating‐up phase for different kind of quartzes: clear natural from Brazil, smoky natural, and synthetic quartz from Sawyer Research Product (Electronic and Premium Q), Toyo, romanian and polish ones, and compares the phenomenon in vacuum and in air for the same applied electric field and gives a model, with which the process could be described.
Coexistent Phases and their Electrical and Structural Behaviour in the Ternary Re/Mo/O System
Authors: Doerr M. , Feller J. , Oppermann H. 
Published: January 2007

AbstractIn order to complete and improve phase diagrams of transition metal oxides the existence and properties of compounds in the Re/Mo/O system have been investigated. Single crystalline solid solutions Re1‐xMoxO2 (0 < x < 0.37) and Mo1‐yReyO2 (0 < y < 0.42) were prepared by Solid State Reactions and Chemical Transport Reactions (CTR) and characterized by means of X‐ray‐diffraction, ICP‐AES, and EPMA. In addition, it was shown that the trioxides Re1‐xMoxO3 or Mo1‐yReyO3 respectively, do not prove a distinct solubility. First results on Re‐doped Magneli phases of Mo are also discussed. There were found two series of solid solutions Mo4‐zRezO11 (0 < z < 0.40) which derive from γ‐Mo4O11 and η‐Mo4O11. The other Magneli phases did not show a significant Re content. Using X‐ray diffraction, AFM and optical microscopy the structure and morphology of single crystals has been studied. It was steated that the dioxide solid solutions were very homogeneous and structural phase transitions depending on x or y did not occur. That is in good agreement with measurements of electrical conductivity σ in the temperature range from 20 K to 300 K in which the samples showed the behaviour of metals with lattice defects. The Magneli phases Mo8O23 and Mo9O26 turned out to be “narrow gap semiconductors” in the low temperature range with activation energies of less than 0.1 eV. The γ‐Mo4 O11‐ and γ‐Mo4O11 crystals, the pure and Re‐doped ones, were found as metallic conductors at higher temperatures and below a transition temperature they show a semiconductive behaviour.
Polymeric Additives: Effects on Crystallization of Hydroxyapatite Scales
Authors: Doherty W. O. S. , Crees O. L. , Senogles E. 
Published: January 2007

AbstractThe effects of some commercial polymeric additives on the nucleation (induction period), crystal growth, and morphology of hydroxyapatite precipitated from pure solutions of the lattice ions have been examined. The inhibitory capacities of these additives for hydroxyapatite scale formed from whole juice samples under conditions similar to those operating in sugar mills have also been determined. The results show that poly(aspartic acid) with Mw of 5700 is the most effective scale inhibitor.
Optical Absorption Spectra of Czochralski‐grown (Dy1‐xGdx)3O12Ga5O12 and Dy3(Ga1‐yAly)5O12 Garnets Relating Unstable Spiral‐shape Growth
Authors: Kimura H. , Numazawa T. , Sato M. , Kochurikhin V. V. , Shimamura K. , Fukuda T. 
Published: January 2007

AbstractOptical absorption has been measured from 700 to 1300 nm for garnet single crystals by substituting Dy or Ga for Gd or Al of Dy3Ga5O12 grown by the Czochralski method, and a suppression of unstable spiral‐shape growth on Dy3Ga5O12 by the substitution was discussed relating the absorption spectra. The total absorption in the single crystals at the wavelength corresponding to the radiation from Ir crucible was decreased relatively with the increase of Gd or Al content. The decrease of this absorption in the single crystals is one of the causes to suppress the unstable spiral‐shape growth.
Piezoelectric and Elastic Properties of Orthorhombic LiH2PO3 and LiH2PO4
Authors: Haussühl S. 
Published: January 2007

AbstractSingle crystals of LiH2PO3 and LiH2PO4, both of space group symmetry Pna21, with dimensions up to 40 mm were grown from aqueous solutions by controlled evaporation. Pyroelectric, dielectric, piezoelectric, elastic and thermoelastic properties were studied by standard methods. The static piezoelectric constants d333 exceed d111 of α‐quartz by only a factor 2. The pyroectric effects reach 3 times and 7 times, respectively, that of tourmaline. The mean elastic stiffness of the phosphite is 13% smaller than that of the phosphate, a phenomenon also observed in the corresponding sodium and potassium salts.
Electrical Characterization of Irradiation plus Annealing – induced VAsZnGa Pairs in p‐type GaAs (Zn) Crystals
Authors: Glinchuk K. D. , Prokhorovich A. V. 
Published: January 2007

AbstractEffect of fast electron irradiation (E =2.2 Mev, ϕc = 1 × 1016 el/cm2) and subsequent annealings (T = 150 to 350 °C, t = 10 to 600 min) of zinc‐doped p‐type GaAs crystals on the formation and dissociation of VAsZnGa, pairs is studied. An analysis of the formation and dissociation kinetics of VAsZnGa pairs permitted to find the diffusion coefficient of radiation‐induced arsenic vacancies D(D = 1.5 × 10−18, 1 × 10−17 and 5 × 10−17 cm2/s at 150, 175 and 200 °C accordingly), their migration energy ϵm(ϵm = 1.1 eV), the binding energy of VAsZnGa, pairs ϵb(ϵb = 0.5 eV), and also their dissociation energy ϵd(ϵd = 1.6 eV).
Some Physical Properties of Ga2Se Single Crystals
Authors: Gamal G. A. , Nagat A. T. , Nassary M. M. , Abou‐Alwafa A. M. 
Published: January 2007

AbstractMeasurements of the electrical conductivity, Hall effect, thermnoelectric power were carried out in a wide temperature range (from about 170 to 475 K) for Ga2Se compound grown in single crystalline form. The present investigation revealed unusual observations in the Hall effect and the scattering mechanisms of the charge carriers indicating that Ga2Se is not a simple semiconductor. Also it showed that Ga2Se has a relatively high value of the thermoelectric power. A lot of physical parameters were deduced in the present study.
Gettering Properties of Praseodymium in GaAs, In0.53Ga0.47As, and InP Grown by Liquid Phase Epitaxy
Authors: Jiang Gwo‐Cherng 
Published: January 2007

AbstractThe incorporation of praseodymium (Pr) into GaAs, In0.53Ga0.47As, and InP during liquid‐phase epitaxy were investigated by double crystal x‐ray diffraction, Hall effect, low temperature photoluminescence (PL) measurements. The lattice mismatch slightly vary with Pr concentration in the growth melts. Examinations of the electrical property illustrate that the lower carriers concentrations and a higher mobilities are obtain from Pr‐doped epilayers than undoped sample (In0.53Ga0.47As and InP). The PL spectra (15‐K) show that the intensity of the impurity related peaks decreases and the near‐band‐to‐band luminescence intensity increase. They also reveal that the impurities are gettered by Pr ions during LPE growth. Thus, for the purpose of purification, proper amount of Pr in the growth melts is suggested. No intra‐4f‐shell transition line is observed from the Pr‐doped GaAs, In0.53Ga0.47As, and InP layers.
Sb2Te3 Single Crystals Doped with Chromium Atoms
Authors: Lošťák P. , Drašar Č. , Navrátil J. , Beneš L. 
Published: January 2007

AbstractChromium‐doped Sb2Te3 single crystals were prepared from elements of semiconductor purity using a modified Bridgman method. The samples of these crystals were characterized by means of X‐ray diffraction analysis, measurements of the reflectivity in the plasma resonance frequency range ωp, of the Hall constant RH and electrical conductivity σ. It was found that the incorporation of Cr atoms into the Sb2Te3 crystal lattice reduces the volume of the unit cell, whereas the values of ωp and RH (i.e. the concentration of holes) remain unaltered and the values of σ decrease with increasing chromium content. This effect is qualitatively explained by an interaction of incorporated Cr atoms with antisite defects of Sb2Te3 crystal lattice. The In (RHσ) vs. In T dependences show that the dominant mechanism of scattering of free charge carriers in the studied crystals is the scattering by acoustic phonons; the presence of chromium atoms increases the scattering rate by ionized impurities.
Growth and Properties of the Organometallic Nonlinear Optical Crystal: Semicarbazide Cadmium Chloride (SCCC)
Authors: Wang B. G. 
Published: January 2007

AbstractSemicarbazide cadmium chloride (SCCC) is an organometallic nonlinear optical crystal. Preparation and crystal growth of SCCC have been studied, thermal and IR spectral properties of the crystal are characterized. Investigations of the molecular and crystal structures show that there is a large charge‐transfer bridge in the molecule, and that the crystal has a distorted polyhedrally‐coordinated structure. The relations between the structures and NLO effects of complex crystals have been discussed, and optimization of structures of organometallic NLO crystals are suggested.
Structural and Spectral Studies of 2‐(3,4,5‐trimethoxyphenyl)‐Benzothiazole
Authors: İde S. , Öztaş S. G. , Ancin N. , Tüzün M. 
Published: January 2007

Abstract2‐(3,4,5‐trimethoxyphenyl)‐benzothiazole, C16H15NO3S was obtained by condensation of 2‐aminobenzenethiol with 3,4,5‐trimethoxybenzoldehyde. The structure of the title compound was indicated by IR, 1H‐NMR, UV spectra and confirmed by an X‐ray analysis. In the molecule the trimethoxyphenyl and benzothiazole groups are connected by a CC bond of 1.478(6) Å. The trimethoxyphenyl except a methoxy group and the benzothiazole group are nearly planar. The dihedral angle between these planes is 8.5(9)°.
Rietveld Refinement of the Crystal Structure of Nickel Hexaamina Perchlorate and ‐Tetrafluorborate
Authors: Lutoslawska‐Rogóż J. , Mucha D. , Hodorowicz S. A. 
Published: January 2007

AbstractRoom‐temperature phases of nickel hexamina perchlorate (NHP) and nickel hexaamina tetrafluorborate (NHT) were analysed by means of X‐ray powder diffractometry. Both compounds crystallize in the cubic system (Fm3m space group) with cell parameters:a= 11.4689 Å for NHP anda= 11.2692 Å for NHT structure, respectively. The crystal structures of these compounds were refined using Rietveld method.
Theoretical Approach to the Deformation‐induced Luminescence in Metals
Authors: Chandra B. P. , Khan M. S. , Singh Seema R. , Ansari M. H. 
Published: January 2007

AbstractThe present paper reports the mechanoluminescence (ML) produced during fracture of metals. The mechanism of ML in metals is based on the generation of holes during the decay of mobile dislocations on the surface and subsequent electron‐hole radiative recombination. The following equation is derived for the transient ML intensity of the fracto‐induced ML in metals
equation image
.The above equation shows that I should be maximum for a particular value of time t. For β 〉 α,
equation image
.This equation shows that I should decrease exponentially with time. For the fracto‐induced ML in metals, tM and Im may be expressed by the following equations
equation image
.The spectroscopy of ML in metals is also discussed. A good correlation is found between the theoretical and experimentals results.
Structural and Thermal Characterization of Zeolite Type Y Modified by Ion Exchange with Zn, Cd, and Hg Cations
Authors: Sarbak Z. 
Published: January 2007

AbstractThe object of our studies was zeolite NaY and its Zn2+‐, Cd2+‐ and Hg2+ modifications obtained by ion‐exchange method. Influence of the above cations on the crystalline structure of zeolite type Y and its thermal stability has been shown on the grounds of X‐ray diffraction, differential thermal analysis, and infrared spectroscopic measurements.