Showing papers on "Ternary operation published in 1992"

Growth and strain compensation effects in the ternary Si1-x-yGexCy alloy system

Abstract: Strain compensation is an important aspect of heterostructure engineering. In this letter, we discuss the synthesis of pseudomorphic Si1−yCy and Si1−x−yGexCy alloy layers on a silicon (100) substrate by molecular beam epitaxy using solid sources and the controlled strain compensation that results from the introduction of the ternary system. The introduction of C into substitutional sites in the crystal lattice is kinetically stabilized by low‐temperature growth conditions (400–550 °C) against thermodynamically favored silicon‐carbide phases. The lattice constant in Ge is about 4% larger than in Si, whereas in diamond it is 52% smaller. Consequently, the compressive strain caused by 10.8% Ge in a pseudomorphic Si1−xGex alloy can be compensated by adding about 1% carbon into substitutional lattice sites of the film assuming Vegard’s law of linear change of the lattice constant in the alloy as a function of the composition. Using x‐ray diffraction, we observe a partial strain compensation in Si0.75−yGe0.25Cy...

Spatial flexibility in ternary complexes between SRF and its accessory proteins.

Abstract: We investigated the sequence requirements for ternary complex formation by the transcription factor SRF and its Ets domain accessory factors Elk-1 and SAP-1 Ternary complex formation is specified by an SRF consensus site CC(A/T)6GG and a neighbouring Ets motif (C/A)(C/A)GGA(A/T), which is contacted by Elk-1/SAP-1 Both the spacing of these sequences and their relative orientation can be substantially altered with little effect on the efficiency of ternary complex formation Efficient ternary complex formation by Elk-1 is mediated by the B box, a conserved 21 amino acid region located 50 residues C-terminal to the Ets domain, which also acts to inhibit autonomous DNA binding Binding studies with the isolated Ets domains indicate that ternary complex formation compensates for low affinity Ets domain-DNA interactions Several naturally occurring SREs containing Ets motifs at different locations to that in the human c-fos SRE allow SAP-1 and Elk-1 recruitment in vitro We discuss the mechanism of ternary complex formation

Binary and ternary fission of hot and rotating nuclei

Abstract: The binary and ternary fission and fusion of hot rotating nuclei have been investigated within the rotational liquid-drop model at finite temperature and including the nuclear proximity energy. The temperature effects are emphasized by the symmetry and mass of the nuclear system due to the modification of the surface tension. With increasing temperature, the fission and fusion barriers decrease and the ridge-line potentials are more accentuated without changing the Businaro-Gallone picture. With increasing mass, the nuclei can support higher angular momenta. Investigation of the ternary fragmentation valley allows one to show that elongated but compact heavy systems can sustain both high temperature and high spin when they are uncompressed, as in peripheral collisions of heavy ions in the intermediate-energy domain.

LiMoN2: The First Metallic Layered Nitride

Abstract: : We report the first example of a layered ternary lithium nitride in which the lithium can be deintercalated and reintercalated. This ternary nitride, LiMoN2, has been synthesized by the reaction of two different precursors, Li2Mo(NtBu)4 and Li2MoO4, with ammonia gas. The structure was refined using a combination of X-ray and neutron powder diffraction data in the space group R3 and the lattice parameters are (A) a=2.8672(3) and c=15.813(3) which were obtained from the neutron data. The ideal structure consists of MoN2 layers with Mo in trigonal prismatic holes and Li in octahedral holes between the MoN2 layers. The diffraction studies indicate the presence of cation anti-site defects; the structure is best described as Solid State Nitrides Li batteries Crystal Structure Magnetic and Electrical Properties (Li0.84Mo0.16) oct(Mo0.84Li0.16)tpN2. LiMoN2 is metallic and Pauliparamagnetic with Xo = 0.59 x 10(6) emu g-1. We have employed a variety of different oxidizing agents for the deintercalation of the lithium from LiMoN2 and have been able to deintercalate up to 64% of the lithium. This deintercalated species can be reintercalated with n-butyllithium (in hexane) at room temperature. Electrochemical studies show a large hysteresis in charge-discharge cycles.

High Pressure Phase Behaviour of Multicomponent Fluid Mixtures

Abstract: 1. Survey of the High Pressure Phase Behaviour of Fluids. Introduction. Phase Behaviour of Binary Fluids. Phase Behaviour of Ternary and Multicomponent Fluids. 2. The Thermodynamics of Phase Equilibria. Criteria for Equilibrium. Coexistent Phases. The Phase Rule. Criteria for Phase Stability. Critical Phases. Consequences for Phase Equilibria Calculations. 3. Models for High Pressure Multicomponent Equilibria. The Phase Integral. Computer Simulation. Conformal Solution Theory. Perturbation Theories. Equations of State. Mixing Rules for Multicomponent Equilibria. An Analytic Description of Attractive Forces in Binary Fluid Mixtures. Equations of State Calculations. 4. Procedure for Determining the Phase Behaviour of Ternary Mixtures: Comparison of Experiment with Theory for Gas-Liquid Critical Temperatures. Determining Stable Ternary Critical Points. Strategies for Ternary Phenomena. Gas-Liquid Critical Properties of Ternary Mixtures. Computing Options for Ternary Calculations. 5. Novel Higher Order Critical Phenomena in Ternary Mixtures. Tricritical Phenomena. Higher-Order Critical Transitions in Ternary Mixtures. 6. Phase Behaviour of Ternary Carbon Dioxide and n-Alkane Mixtures. Methane + n-Hexane + Carbon Dioxide. Ethane + n-Hexane + Carbon Dioxide. Propane + n-Hexane + Carbon Dioxide. n-Butane + n-Hexane + Carbon Dioxide. n-Pentane + n-Hexane + Carbon Dioxide. n-Heptane + n-Hexane + Carbon Dioxide. n-Octane + n-Hexane + Carbon Dioxide. n-Oxtane + n-Hexane + Carbon Dioxide. n-Nonane + n-Hexane + Carbon Dioxide. n-Decane + n-Hexane + Carbon Dioxide. 7. Ternary Tetrafluoromethane and n-Alkane Mixtures. Methane + Ethane + Tetrafluoromethane. n-Propane + i-Butane + Tetrafluoromethane. n-Propane + n-Butane + Tetrafluoromethane. n-Propane + n-Pentane + Tetrafluoromethane. 8. Ternary Mixtures Containing Nitrogen. Methane + Ethane + Nitrogen. Methane + n-Pentane + Nitrogen. Ethane + Nitrogen + Water. n-Pentane + Nitrogen + Water. 9. Ternary Mixtures Containing Water and n-Alkanes. Ethane + Propane + Water. Ethane + n-Pentane + Water. Ethane + n-Hexane + Water. n-Pentane + n-Hexane + Water. Ethane + Carbon Dioxide + Water. Appendix A. Appendix B. Subject Index. Author Index. The book contains extensive references.

Thermodynamic calculation of the ternary TiAlNb system

Abstract: Phase equilibria of the ternary TiAlNb system are dominated by the large range of homogeneity of (β-Ti,Nb), the binary intermetallic compounds of the NbAl and TiAl systems and the formation of two ternary compounds. The available ternary experimental data, together with a thermodynamic extrapolation of the ternary system from the binary systems, have been used to calculate the ternary phase diagram. The model descriptions of the Gibbs energies of most of these compounds are given by the existing calculations of the binary systems. In order to model a phase which is present in only one binary system, but has a ternary homogeneity range, a hypothetical phase with the same structure was analytically described for each binary system. Such a phase would, of course, be metastable in the other binary systems. Constraints on the Gibbs energies of formation were derived from the crystal structures of the corresponding ordered compounds. These same constraints were employed for the corresponding phases in the ternary system. In a final optimization step, ternary parameters were introduced and adjusted to the available experimental data. The as-derived description of the ternary TiAlNb system can be used to estimate single or multiphase fields and thermodynamic quantities where no experimental data are yet available. It is also useful as an indicator of problem areas for which additional experimental data are required.

Prediction of Critical Micelle Concentrations of Nonideal Ternary Surfactant Mixtures

Abstract: We present a method for predicting critical micelle concentrations (cmc's) of nonideal ternary surfactant mixtures based on the use of a molecular-thermodynamic theory to predict regular solution theory β interaction parameters for the component surfactant pairs. The ternary mixture cmc predictions, which are generated using experimental data only for the single surfactant cmc's, compare well with experimentally measured mixture cmc values for several ternary surfactant mixtures. The molecular-thermodynamic theory used to predict the β parameters is based on evaluating free-energy contributions to mixed micelle formation, and uses the molecular structures of the surfactants and the solution conditions as inputs. We also present a detailed derivation of the expression for the mixture cmc of ternary surfactant mixtures, comparing the pseudophase separation approximation for mixed micelles with the molecular-thermodynamic theory for mixed micelles. We show that if (i) the mixed micelle aggregation number is ...

Solid state amorphization in binary Ti-Ni, Ti-Cu and ternary Ti-Ni-Cu system by mechanical alloying

Abstract: An amorphous phase has been synthesized by mechanical alloying in a planetary mill over a nickel content range of 10–70 at.% in the TiNi system and a copper content range of 10–50 at.% in the TiCu system. In the case of ternary TiNiCu alloys the glass-forming composition range has been found to be given by x = 10–20 for Ti60Ni40 − xCux, x = 10 – 30 for Ti50Ni50 − xCux and x = 10 – 40 for Ti40Ni60 − xCux alloys. The difficulty in the amorphization of copper-rich compositions is explained in the light of enthalpy composition diagrams calculated for the ternary solid solution and the amorphous phase.

Correlation and prediction of dense fluid transport coefficients. III. n-alkane mixtures

Abstract: Viscosity and thermal conductivity coefficients for binary, ternary, and quaternary n-alkane mixtures are predicted over extended ranges of temperature and pressure, in excellent agreement with experiment, by extension of a method recently described for the correlation of n-alkane transport coefficients. The outstanding advantage of this approach is that there are no adjustable parameters. Furthermore, in contrast with other mixture viscosity equations, this scheme does not require experimental viscosity coefficient data for the pure components under the same conditions of temperature and pressure.

Surface tension of binary and ternary aluminium alloys of the systems Al-Si-Mg and Al-Zn-Mg

Abstract: The surface tension and density of liquid binary and ternary aluminium alloys of the systems Al-Si-Mg and Al-Zn-Mg (Si, Mg and Zn contents less than 19, 8 and 20 wt %, respectively) have been measured by means of the maximum bubble pressure method. A semi-empirical theory, which relates the surface tension to bulk thermodynamic properties, is used to calculate the surface tension of the binary alloys and discuss the experimental data. For the ternary alloys, the present results indicate that in the range of compositions explored here, the properties of the ternaries can be obtained from those of the binaries. Comparison with results previously reported by other authors is made.

Copolymers as amphiphiles in ternary mixtures: An analysis employing disorder, equimaxima, and Lifshitz lines

Abstract: We study the phase diagram and scattering functions of a ternary mixture of A and B homopolymers, in equal concentrations, and AB diblock copolymer. We locate the disorder line, which marks the appearance of damped oscillatory decaying correlation functions in the system, and also the Lifshitz and equimaxima lines of the structure functions. At these lines, the oscillatory component becomes dominant in a given correlation so that the peak in scattering intensity is no longer at the zero wave vector. We find that while the Lifshitz line of the structure function of all A monomers is quite close to the disorder line, that of A monomers in the homopolymer only is far from it. This shows that the copolymer orders the homopolymers inefficiently, a behavior which is also reflected in the copolymer’s weak ability to solubilize them, and which contrasts with the amphiphilic solubilizers of oil and water. The disorder line and all Lifshitz lines meet at a Lifshitz tricritical point. As these ternary mixtures provi...

Density-tuned polyolefin phase equilibria. 2. Multicomponent solutions of alternating poly(ethylene-propylene) in subcritical and supercritical olefins. Experiment and SAFT model

Abstract: A combination of a high pressure exoeriment (variable-volume optical cell) and molecular theory (statistical associating fluid theory SAFT) is used to quantify systematically the effe ts of pressure, temperature, composition and polymer and solvent size on LCST, UCST, VL and VLL transitions in binary, ternary and quaternary olefin-polyolefin systems. Supercritical ethylene is found to reduce drastically the mutual miscibility of 1-butene+poly(ethylene-alt-propylene) (PEP) and 1-hexene+PEP and hence, to increase the LCST pressures needed to maintain the ternary mixtures in a one-phase region. This ethylene antisolvent effect is modeled with SAFT

Packing of Ternary Mixtures of Nonspherical Particles

Abstract: An experimental investigation of the packing of some ternary mixtures of nonspherical particles has been conducted. The double extrapolation method is used to determine the packing density of a particle mixture in infinite space. The application of experimental design to particulate mixture problems is demonstrated. The results indicate that the similarity between the packing systems of spherical and nonspherical particles can be readily depicted in terms of specific volume variation.

Pteridine-containing ternary and quaternary complexes as models for metalloenzyme-pterin cofactor-substrate association. Structure of ternary copper(II)-2,2'-bipyridine-lumazine complex and successful equilibrium study of a quaternary copper(II) system

Abstract: Structures and stabilities of pteridine-containing ternary and quaternary Cu(II) complexes have been studied by synthetic, spectroscopic, potentiometric, and X-ray diffraction methods.

Ion migration in chalcopyrite semiconductors

Abstract: Quantitative data are presented that show partial ionic conductivity of Cu or Ag in ternary and quaternary electronic semiconductors, with idealized stoichiometry Cu x Ag 1-x InSez. A trend of increasing facility of ionic motion with increasing Ag content was observed. Ionic transference numbers up to 0.13 and 0.55 were measured for CuInSe 2 and AgInSe 2 , respectively. This trend can be correlated with the degree of compactness of the structure. It is supported by results from measurements of effective values of chemical diffusion coefficients, obtained by a potentiostatic current decay technique

Evaluation of refractory intermetallics with A15 structure for high temperature structural applications

Abstract: With the advent of ceramic superconductors, while interest in the A15 intermetallics such as Nb 3 Al is declining, their potential for high temperature structural applications appears promising. The A15 compounds, though considered to have the simplest of the topologically closed packed structures, form a distinct class of intermetallics with a cubic structure and are adjacent phases to the refractory metal solid solutions. This report summarizes the evaluation of microstructures, mechanical properties and cyclic oxidation resistance of Nb 3 Al and Cr 3 Si and their ternary alloys, and to a limited extent binary V 3 Si. The mechanical properties of binary compounds, elastic modulus, ultimate strength and creep behavior, are compared with known data for other A15 compounds. Solubility limits, melting point suppression and enhancement in creep resistance of several ternary alloys based on Nb 3 Al and Cr 3 Si are summarized. The mechanical properties and microstructural observations are discussed from the perspective of developing high temperature structural materials based on A15 intemetallics.

Three Types of Ternary Selenides with Layered Composite Crystal Structures Formed in the Pb–Nb–Se System

Abstract: Three types of ternary selenides with layered composite crystal structures, (PbSe)1.14NbSe2[A], (PbSe)1.14(NbSe2)2[B] and (PbSe)1.14(NbSe2)3[C], have been prepared and characterized by powder X-ray diffraction, electron diffraction, intercalation and electric resistivity measurement. Results suggest that each selenide consists of PbSe layers(two-atoms-thick) and NbSe2 sandwiches(three-atoms-thick) stacked alternately with the ratios of 1:1 for A, 1:2 for B and 1:3 for C, respectively. Electric resistivity measurements suggest that B and C are superconductors whose transition temperatures are 3.4 K and 4.8 K, respectively.

Binding and catalysis with a metal-induced ternary complex of an ethylenediamine-substituted cyclodextrin

Abstract: The binary complex (CDen2Cu) from 6-(2-aminoethyl)amino-6-deoxy-β-cyclodextrin (CDen) and Cu2+ binds methyl orange (MO) about twice as efficiently as CDen alone, whereas brilliant yellow (BY), owing to the extended shape of this substrate, shows an approximately sevenfold increase in K. Deacylation of p-nitrophenyl benzoate (PNPB) shows, with an ethylenediamine model compound, the expected rate enhancement, which is retarded upon addition of sufficient Cu2+ to block the N lone pairs. In sharp contrast, deacylation of PNPB is accelerated by CDen2Cu, whereas the ‘shorter’p-nitrophenyl acetate (PNPA), being less suited to formation of a ternary inclusion complex, again exhibits a rate decrease. Catalytic rate constants kc and Michaelis–Menten constants KD are obtained from Lineweaver–Burk or Eadie plots; equilibrium constants for MO and BY have been studied at different wavelengths. The problems associated with the evaluation of the multiple variables in such equilibria are illustrated.

Composite Si/C/N powder production by laser induced gas phase reactions

Abstract: Ultrafine amorphous Si/C/N ternary powders have been prepared in a CO2 laser assisted process. We demonstrate the possibility to drive the C/N ratio in the powder by properly choosing the experimental conditions and the gaseous reactant ratio in the initial mixture containing silane, dimethylamine, and ammonia. A kinetic model that accounts for reaching the equilibrium between the gaseous reaction intermediates and the solid products is proposed.

Thermodynamic optimization of the Mg-Al-Si phase diagram

Abstract: An optimized phase diagram for the ternary Mg-Al-Si system was constructed using experimental data from the literature. The binary excess terms were represented by Redlich-Kister polynomial expressions. The two binary Mg-Si and Al-Si systems were re-adjusted using newer phase stabilities and experimental results. The ternary system is described, using the Mg-Al system of Saunders by Muggianu's formula and two additional terrnary excess terms for liquid, which were adjusted to experimental values from the literature by the least squares method. A number of vertical and isothermal sections were calculated along with the liquidus surface. The optimized diagram is in acceptable agreement with the experimental data.

Optical analysis of absorbing thin films: application to ternary chalcopyrite semiconductors.

Abstract: The refractive index n and the absorption coefficient-alpha of radio frequency sputtered CuGaSe2 and CuInSe2 thin films were obtained by means of transmissivity (T) and reflectivity (R) measurements at normal incidence. The optical properties were determined from the rigorous expressions for the transmission and the reflection in an air/film/(glass)substrate/air multilayer system. The solutions to this system of equations are not unique, and the physically meaningful solution is identified by trying different thicknesses in the numerical approach. Usually, nonacceptable n dispersion curves are found for all thicknesses. To be able to obtain a good n dispersion curve and, therefore, a correct absorption coefficient, we propose a simple modification of the equations for R and T through a factor called the coherence factor (CF). Because of the surface roughness and the nonuniformity of n and alpha, the light rays that reflect internally in the interface between the substrate and the film have a random difference in optical path. The CF accounts for this effect. This modification leads to an unambiguous and accurate determination of the optical properties and thickness of thin films for all wavelengths where transmission is not negligible. The CF is shown to be greatly dependent on the thickness of the film. This method can be used even when the R and T spectra do not have interference fringes. This method is applied successfully to the optical analyses, in the 0.4-2.5-mu-m wavelength range, of CuInSe2 and CuGaSe2 ternary chalcopyrite thin films deposited onto glass substrates by radio-frequency sputtering.