Showing papers on "Ternary operation published in 1991"

Why are some oxides metallic, while most are insulating?

Abstract: A large variety of undoped binary and ternary transition metal oxides, including formally divalent, trivalent and tetravalent metal cations, have been examined These 76 compounds are classified as either “metals”, “insulators”, or having a “metal-to-insulator” transition In an attempt to understand these variations, the Zaanen-Sawatzky-Allen framework was used in which each compound can be characterized by three parameters: the Coulomb correlation or disproportionation energy (U′), the charge-transfer energy (Δ) and the bandwidth (W) Assuming W is constant, we have calculated U′ and Δ using a simple ionic model, which includes only the gas phase ionization potentials and the bare electrostatic Coulomb interactions between the ions With this model, the occurence of metallic conductivity is remarkably well accounted for in these oxides

Phase equilibria and structures in ternary systems of a cationic surfactant (C16 TABr or (C16 TA)2SO4), alcohol, and water

Abstract: The dependence of alcohol chain length on the isothermal phase behavior of the ternary systems hexadecylrrimethylammonium bromide/alcohol/water has been investigated. A liquid crystalline phase (the normal hexagonal one) occurs in the phase diagrams along the surfactant/water axis and this phase extends in the interior of the diagrams.

Raman scattering as a compositional probe of II‐VI ternary semiconductor nanocrystals

Abstract: We show how Raman optic‐mode peak positions and relative intensities can be used in a straightforward way to determine crystallite composition in CdSxSe1−x nanocrystals embedded in glass. These Raman techniques are particularly useful for low‐concentration or small‐crystallite‐size composites where x‐ray diffraction is not a viable technique for structural characterization of crystallites.

Mixed ternary heterojunction solar cell

Abstract: A thin film heterojunction solar cell and a method of making it has a p-type layer of mixed ternary I-III-VI2 semiconductor material in contact with an n-type layer of mixed binary II-VI semiconductor material. The p-type semiconductor material includes a low resistivity copper-rich region adjacent the back metal contact of the cell and a composition gradient providing a minority carrier mirror that improves the photovoltaic performance of the cell. The p-type semiconductor material preferably is CuInGaSe2 or CuIn(SSe)2.

Structural and magnetic properties of ternary nitrides R2Fe17Nx (R ≡ Nd, Sm)

Abstract: A structural and magnetic characterization of the new ternary R2Fe17Nx compounds has been carried out by means of neutron powder diffraction and χac susceptibility measurements. Preliminary high field magnetization measurements are also presented. These new nitrides have been found to retain the 2:17 host metal symmetry. Nitrogen is accommodated in octahedral sites. The effects of nitrogenation on the magnetic properties are discussed. The high field measurements have allowed us to determine the anisotropy field of the Sm2Fe17N2.2 compound in the range from 4.2 to 300 K.

Ternary mutual diffusion coefficients of MgCl2 + MgSO4 + H2O and Na2SO4 + MgSO4 + H2O from Taylor dispersion profiles

Abstract: The Taylor dispersion (peak-broadening) technique is used to measure the ternary mutual diffusion coefficients of the mixed salt solutions MgCl2 + MgSO4 + H2O and Na2SO4 + MgSO4 + H2O at 25 °C. The...

Ternary diffusion coefficients of 18-crown-6 ether–KCl–water by direct least-squares analysis of Taylor dispersion measurements

Abstract: The Taylor dispersion (peak-broadening) method is used to measure the ternary multicomponent diffusion coefficients of three-component liquid systems. The diffusion coefficients are evaluated directly by fitting the mathematical solutions of the dispersion equation to eluted solute peaks detected by differential refractometry. Tests with sucrose–KCl–water and NaCl–MgCl2–water indicate that the least-squares treatment is more accurate than a previously reported moments analysis procedure. Ternary diffusion coefficients are also reported for aqueous solutions of 18-crown-6 ether–KCl at 25 °C. The interaction between the solute fluxes owing to the formation of the ether–K+ complex is discussed.

Chapter 1 Magnetic properties of ternary rare-earth transition-metal compounds

Abstract: Publisher Summary This chapter discusses the magnetic properties of ternary rare-earth transition-metal compounds. The magnetism of pure elements concerns the properties of about 20 metals, mostly from the 3d or 4f series. Binary intermetallic compounds are much more numerous. Magnetic binaries may involve one or both elements with magnetic moments. Composition adds a further dimension, with many binary diagrams exhibiting ranges of solid solubility and a number of intermetallic phases, each with its particular structure. Sometimes, the distinction is a matter of site preference, such as ordered substitution of one quarter of the sites of the fcc structure leads to a Cu 3 Au-type structure compound, whereas complete disorder produces an A 75 B 25 fcc solid solution. The magnetic properties of binary intermetallic compounds, usually involving a 3d or 4f element, and sometimes both, are reviewed in the chapter. The order of decreasing transition-metal content the magnetic properties of ternaries with structures related to a binary structure type is discussed. The true ternary compounds are also discussed in the chapter.

Carbon Incorporation in (AlGa)As, (AlIn)As and (GaIn)As Ternary Alloys Grown by Molecular Beam Epitaxy

Abstract: Carbon incorporation in III-V ternary alloys, (AlGa)As, (AlIn)As and (GaIn)As, for the entire composition range is investigated using solid-source molecular beam epitaxy. On the binary corners, carbon-doped GaAs and AlAs show p-type conduction, while carbon-doped InAs shows n-type conduction. At a constant doping level, conduction-type inversion is found to occur in the (GaIn)As layer at an InAs mole fraction of about 0.6 and in the (AlIn)As layer at about 0.9. Hall mobilities and free carrier concentrations decrease around the compositions where the conduction-type inversions occur. The conduction-type inversion phenomena and the behavior of carrier mobilities are explained in terms of a self-compensation mechanism.

A thermodynamic analysis of the Al-C-Fe system

Abstract: In this work, a thermodynamic analysis of the Al-C-Fe system is carried out covering a wide tem-perature range. The sublattice model of Hillert for the solution phases and the Redlich-Kister-Mug-gianu formalism for the interaction parameters are used. The binary and ternary interaction parameters and the Gibbs energies of formation of the carbides are obtained by optimization of the thermochemical and the phase diagram data. The results include a liquidus projection, details of the four-phase invariant reactions, a reaction table, and eight isothermal sections covering the tempera-ture range from 2000 °C to 800 ’C.

Binary and ternary equilibria for C8 aromatics on KY faujasite

Abstract: Adsorption equilibrium data for binary and ternary liquid-phase mixtures of the C 8 aromatic isomers o-xylene (OX), p-xylene (PX), m-xylene (MX), and ethylbenzene (EB) on K-Y faujasite are reported Although the deviations from ideal thermodynamic behavior in these systems are not large (excess free energies are ∼50 cal/mol), these nonidealities are sufficient to cause significant variations in separation factor with composition

Occurrence of Dielectric 1:1:4 Compound in the Ternary System BaO—Ln2O3—TiO2 (Ln = La, Nd, and Sm): II, Reexamination of Formation of Isostructural Ternary Compounds in Identical Systems

Abstract: To establish the correct composition of a ternary compound having higher TiO2 content in the BaO—Nd2O3—TiO2 system, the phase change of samples with variable controlled compositions, which were prepared by a modified coprecipitation method, was examined by X-ray diffractometry and Raman spectroscopy. Identification of the phases present in the calcined samples and microstructural evidence for the fired product from electron microprobe analysis clearly indicated that the ternary compound having the composition 1:1:4 occurs in the present system. X-ray powder diffraction data of the isostructural 1:1:4 and 1:1:3 compounds in each identical ternary system (Ln = La, Nd, and Sm) were refined and indexed. Partial subsolidus phase relations consisting of different composition triangles were also proposed for the present ternary systems.

Structural and optical properties of Al0.48In0.52As layers grown on InP by molecular beam epitaxy: Influence of the substrate temperature and of a buffer layer

Abstract: We have studied the crystalline and optical properties of AlyIn1−yAs ternary alloys grown by molecular beam epitaxy on InP substrates. We obtain Al0.48In0.52As layers with both high structural quality and excellent optical performance by growing (i) at high substrate temperature (600 °C), (ii) on a high‐quality GaxIn1−xAs/AlyIn1−yAs short‐period superlattice buffer, (iii) or on a high‐quality GaxIn1−xAs buffer layer, as attested by double‐crystal x‐ray diffraction and photoluminescence measurements. In addition the experimental results indicate a significant reduction of the clustering level in these samples which is interpreted in terms of a smoothing of the growth front, a thermodynamically controlled growth mode, and the interplay between In segregation and In desorption. Our investigations further show that the improvement of the structural quality and of the optical performance are strongly correlated. Finally, we report the first evidence of excitonic features in photoluminescence excitation spectra of the AlyIn1−yAs ternary alloy.

Temperature dependencies of ternary ion–molecule association reactions yielding N+3, N+4, and (CO)+2

Abstract: The temperature dependencies of four ternary positive ion–molecule association reactions yielding the products N+3, N+4, and (CO)+2 have been studied using a high pressure pulsed source. The pressure range 0.5 to 4.0 Torr and the temperature range 220 to 500 K were examined. When the experiments were conducted in a pure gas, the third‐order rate coefficients were found to follow an overall T−n dependence with 2.1≤n≤2.4. For the case of N+4 formation in a mixture of helium and nitrogen, a power law dependence was not found. The measured pressure and temperature dependencies indicate that the low‐pressure limit for all of the reactions extends to neutral number densities as high as 1017 cm−3 throughout the experimental temperature range. The measurements support the existence of a temperature dependence in the stabilization of the intermediate complex for both molecular and atomic third bodies. The results are discussed in light of current models of the ternary association process.

A thermodynamic assessment of the Fe-N-Ti system

Abstract: A thermodynamic analysis of phase equilibria in the Fe-N-V system has been carried out on the basis of the established three binary descriptions and selected ternary experimental data. The two-phase equilibrium between austenite and VN phase was treated as a portion of the miscibility gap in the fcc phase. A set of isothermal sections was presented in the whole range of compositions. Some thermodynamic analysis was carried out on the solubility products of VN in ferrite and austenite.

Characteristics of binary and ternary blends of poly (p‐phenylene sulfide) with poly(bis phenol A) sulfone and polyetherimide

Abstract: An experimental study of the phase morphology and mechanical properties of binary blends of poly(p-phenylene sulfide) (PPS) with both polyetherimide (PEI) and poly(bis phenol A) sulfone (PSF) is described. We also study the ternary system PPS-PEI-PSF. Differential scanning calirometry indicated the blends are immiscible; these findings were confirmed by scanning electron microscopy. Both PEI and PSF were found capable of improving the impact strength and elongation-to-break characteristics of PPS in binary blends and ternary systems.

A new dense-Kondo compound CeNiAl4

Abstract: Experiments of electrical resistivity, specific heat and magnetic susceptibility of a ternary intermetallic compound CeNiAl 4 have been carried out. It is found that CeNiAl 4 is a new member of the dense-Kondo compounds in the valence-fluctuation regime and that CeNiAl 4 is nonmagnetic above 1.6 K. The susceptibility χ 0 and the electronic specific heat coefficient γ 0 which are extrapolated to 0 K are 5.6×10 -3 emu/mol and 204 mJ/mol·K 2 , respectively. The Kondo temperature T K is estimated to be 67 K or 86 K.

Identification of modes in dynamic scattering from ternary polymer mixtures and interdiffusion

Abstract: It is shown that the two exponential modes in dynamic scattering from ternary polymer mixtures cannot in general be identified with the interdiffusion and cooperative diffusion processes, contrary to recent suggestions in the literature. Conditions under which such an identification is possible are obtained. General expressions for the interdiffusion and cooperative diffusion coefficients associated with a given pair of components A and B in a ternary or in general in a multicomponent polymer mixture are obtained in terms of the partial mobilities μ αβ and partial scattering functions S αβ (q) of the A and B homopolymers

Thermodynamic calculation of phase diagrams of the 60 common-ion ternary systems containing cations Li, Na, K, Rb, Cs and anions F, Cl, Br, I

Abstract: The phase diagrams of all 60 possible common-ion ternary alkali halide systems were calculated thermodynamically. The thermodynamic properties of the ternary phases were calculated from the optimized properties of the binary subsystems, which were obtained from previously reported critical evaluations of binary data. Calculated ternary phase diagrams are compared with experimental diagrams in those 47 systems for which the latter are available. In most cases, agreement is within experimental error limits. For five systems, a small empirical correction term was added to the Gibbs energy expression in order to bring the calculated and reported diagrams into coincidence. The calculated ternary diagrams are considered to be the best evaluated diagrams that can be deduced from currently available data. A probable maximum inaccuracy was estimated for each system.

Multiphase equilibrium behavior of the mixture ethane + methanol + 1-decanol

Abstract: The liquid-liquid-vapor (LLV) phase equilibria of the ternary mixture ethane + methanol + 1-decanol were experimentally studied by using a visual cell (stoichlometric) technique with pressure discrimination of ±0.01 bar, achieved by coupling a dead-weight gauge to the cell pressure transducer. The pressure, phase compositions, and molar volumes of the two liquid phases of the ternary LLV system are reported at 295.15 K