Showing papers on "Ternary operation published in 2002"

Pyroelectric properties of Al(In)GaN/GaN hetero- and quantum well structures

Abstract: The macroscopic nonlinear pyroelectric polarization of wurtzite AlxGa1-xN, InxGa1-xN and AlxIn1-xN ternary compounds (large spontaneous polarization and piezoelectric coupling) dramatically affects the optical and electrical properties of multilayered Al(In)GaN/GaN hetero-, nanostructures and devices, due to the huge built-in electrostatic fields and bound interface charges caused by gradients in polarization at surfaces and heterointerfaces. Models of polarization-induced effects in GaN-based devices so far have assumed that polarization in ternary nitride alloys can be calculated by a linear interpolation between the limiting values of the binary compounds. We present theoretical and experimental evidence that the macroscopic polarization in nitride alloys is a nonlinear function of strain and composition. We have applied these results to interpret experimental data obtained in a number of InGaN/GaN quantum wells?(QWs) as well as AlInN/GaN and AlGaN/GaN transistor structures. We find that the discrepancies between experiment and ab initio theory present so far are almost completely eliminated for the AlGaN/GaN-based heterostructures when the nonlinearity of polarization is accounted for. The realization of undoped lattice-matched AlInN/GaN heterostructures further allows us to prove the existence of a gradient in spontaneous polarization by the experimental observation of two-dimensional electron gases?(2DEGs). The confinement of 2DEGs in InGaN/GaN QWs in combination with the measured Stark shift of excitonic recombination is used to determine the polarization-induced electric fields in nanostructures. To facilitate inclusion of the predicted nonlinear polarization in future simulations, we give an explicit prescription to calculate polarization-induced electric fields and bound interface charges for arbitrary composition in each of the ternary III-N alloys. In addition, the theoretical and experimental results presented here allow a detailed comparison of the predicted electric fields and bound interface charges with the measured Stark shift and the sheet carrier concentration of polarization-induced 2DEGs. This comparison provides an insight into the reliability of the calculated nonlinear piezoelectric and spontaneous polarization of group III nitride ternary alloys.

Normal Alkanes, Multialkane Synthetic Model Mixtures, and Real Petroleum Waxes: Crystallographic Structures, Thermodynamic Properties, and Crystallization

Abstract: A general review is presented concerning jointly the crystallographic structures and the solid−solid and solid−liquid transition temperatures and enthalpies in the pure normal alkanes, as well as the structural and thermodynamic behavior of their synthetic binary, ternary, and multinary model mixtures and of real petroleum waxes. A major part of the structural and thermodynamic data of the literature, relative to the pure n-alkanes, are listed from methane up to the alkane with carbon atom number equal to 390. Variation relationships of the crystallographic long c-parameter that corresponds to the periodicity of the molecule layer packing along their axis, melting temperatures, and transition enthalpies are given as a function of the carbon atom number. The study of the literature on the n-alkane mixtures highlights the existence of isostructural binary, ternary, and multinary intermediate solid solutions which can be likened to a single pseudocomponent. This intermediate solid solution is equivalent to a...

Metal nitride formation

Abstract: A process for treating refractory metal-boron layers deposited by atomic layer deposition resulting in the formation of a ternary amorphous refractory metal-nitrogen-boron film is disclosed. The resulting ternary film remains amorphous following thermal annealing at temperatures up to 800° C. The ternary films are formed following thermal annealing in a reactive nitrogen-containing gas. Subsequent processing does not disrupt the amorphous character of the ternary film. arrangement where a blended solution is supplied to a remote point of use.

Optical functions of chalcopyrite CuGa x In 1-x Se 2 alloys

Abstract: We report pseudodielectric functions of the quaternary semiconductor alloys CuGaxIn1-xSe2. Measurements were done in polycrystalline samples from 0.7 to 5.2 eV at room temperature by spectral ellipsometry. Accurate values of refractive indices n and extinction coefficients k representative of the bulk materials are obtained from the data. The structures observed in are analyzed by fitting the numerically differentiated spectra of d2 (ω)/dω2 to analytic line shapes. The obtained energies are related to given inter-band transitions by taking into account the electronic band structures of the ternary end-point compounds.

Particle interactions involved in aerosol dispersion of ternary interactive mixtures

Abstract: Purpose. To investigate the mechanism of action of ternary components within dry powder aerosols. Methods. Ternary interactive mixtures were prepared containing salbutamol sulphate (SS), coarse lactose carriers and either micronized lactose (ML) or micronized glucose (MG). In vitro drug and excipient aerosol deposition was performed using a twin-stage impinger (TSI) at 60 L/min with a Rotahaler device. Adhesional properties of the lactose carrier were examined using an atomic force microscope (AFM) colloidal probe technique. Result. The fine particle fraction (FPF) from ternary mixtures were dependent upon carrier type (p < 0.001), ternary concentration (p < 0.001) and ternary component type (p < 0.05). Ternary mixtures produced higher FPF than binary mixtures, except those containing Superfine (SF), which was attributed to the high proportion of intrinsic fine carrier particles. The higher FPF obtained from ternary mixtures was independent of the mixing order (p = 0.08). Increased adhesion force was observed on the carrier surface following the addition of ternary components (p < 0.001). Conclusion. The results confirm that ternary components increase aerosol deposition of powder mixtures. Some results were not entirely consistent with the saturation of active site theory and a hypothesis involving competitive and multilayer adhesion was proposed and requires further testing.

Phase equilibria and solidification properties of Sn-Cu-Ni alloys

Abstract: Ternary Sn-Cu-Ni alloys were prepared and annealed at 240°C. The annealed alloys were metallographically examined and the equilibrium phases formed were identified on the basis of compositional determinations and x-ray diffraction (XRD) analysis. The isothermal section of the ternary Sn-Cu-Ni system at 240°C was proposed on the basis of experimental results of this study and related information on phase equilibrium available in the literature. The binary compounds, Cu6Sn5, Ni3Sn2, and Ni3Sn4, have very extensive ternary solubility. Continuous solid solutions form between Cu and Ni as well as between Cu3Sn and Ni3Sn. In addition to the isothermal section, the liquidus projection of the Sn-Cu-Ni system was determined based on results from the existing literature. Interfacial reactions between Sn-Cu alloys and Ni substrate and the primary solidification phases of various Sn-Cu-Ni alloys were also examined in this study.

Multiple precursor cyclical deposition system

Abstract: Embodiments of the present invention relate to an apparatus and method of cyclical deposition utilizing three or more precursors in which delivery of at least two of the precursors to a substrate structure at least partially overlap. One embodiment of depositing a ternary material layer over a substrate structure comprises providing at least one cycle of gases to deposit a ternary material layer. One cycle comprises introducing a pulse of a first precursor, introducing a pulse of a second precursor, and introducing a pulse of a third precursor in which the pulse of the second precursor and the pulse of the third precursor at least partially overlap. In one aspect, the ternary material layer includes, but is not limited to, tungsten boron silicon (WBxSiy), titanium silicon nitride (TiSixNy), tantalum silicon nitride (TaSixNy), silicon oxynitride (SiOxNy), and hafnium silicon oxide (HfSixOy). In one aspect, the composition of the ternary material layer may be tuned by changing the flow ratio of the second precursor to the third precursor between cycles.

Synergistic complexation of Eu3+ by a polydentate ligand and a bidentate antenna to obtain ternary complexes with high luminescence quantum yields

Abstract: A series of ternary Eu3+ complexes are presented consisting of a polydentate m-terphenyl-based Eu3+ complex (Eu)1 and different antenna chromophores possessing lanthanide(III) ion coordinating prop...

Superconductivity of Ca(Al0.5,Si0.5)2, a ternary silicide with the AlB2-type structure

Abstract: A ternary silicide Ca(Al0.5,Si0.5)2 was prepared by Ar arc melting. Powder x-ray diffraction measurement indicates that it has the AlB2-type structure with lattice constants of a=4.1905(5) and c=4.3992(8) A, where Si and Al atoms are arranged in the disordered honeycomb lattice and Ca atoms are intercalated between them. The silicide is isostructural with a superconductor MgB2. Electrical resistivity and dc magnetization measurements revealed that it is a superconductor with a TC of 7.7 K.

An improved model for ternary nucleation of sulfuric acid–ammonia–water

Abstract: A revised homogeneous ternary nucleation model in H2O–H2SO4–NH3 vapors is presented. The model is based on a self-consistent version of classical nucleation theory with a rigorous treatment of nucleation kinetics. The calculation of equilibrium vapor pressures is completely revised and the effect of H2O–H2SO4 hydration is considered in detail. Compared to earlier models, the new model is able to predict nucleation rates over a wider range of temperatures and trace gas concentrations. A considerable dependence on relative humidity is found. The critical clusters corresponding to significant nucleation rates typically contain less than ten molecules and consist almost exclusively of H2SO4 and NH3.

Phase Behavior and Hydrogen Bonding in Ternary Polymer Blends of Phenolic Resin/Poly(ethylene oxide)/Poly(ε-caprolactone)

Abstract: The phase behavior and hydrogen bonding in ternary polymer blends of phenolic resin, poly(ethylene oxide) (PEO), and poly(e-caprolactone) (PCL) were investigated by using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Although all three binary blends are respective miscible, there exists a closed immiscibility loop in the phase diagram due to the so-called “Δχ” and “ΔK” effects in this hydrogen-bonded ternary polymer system. The interassociation equilibrium constant based on the Painter−Coleman association model between phenolic resin and PEO can be indirectly calculated from the fraction of hydrogen-bonded carbonyl groups. Quantitative analyses show that the hydroxyl−ether interassociation is more favorable than the hydroxyl−carbonyl interassociation at room temperature. The interaction energy density value of BPEO/PCL= −2.85 cal/cm3 was obtained by comparing the theoretically predicted phase diagram with experimental data.

Eutectic colony formation: a phase-field study.

Abstract: Eutectic two-phase cells, also known as eutectic colonies, are commonly observed during the solidification of ternary alloys when the composition is close to a binary eutectic valley. In analogy with the solidification cells formed in dilute binary alloys, colony formation is triggered by a morphological instability of a macroscopically planar eutectic solidification front due to the rejection by both solid phases of a ternary impurity that diffuses in the liquid. Here we develop a phase-field model of a binary eutectic with a dilute ternary impurity. We investigate by dynamical simulations both the initial linear regime of this instability, and the subsequent highly nonlinear evolution of the interface that leads to fully developed two-phase cells with a spacing much larger than the lamellar spacing. We find a good overall agreement with our recent linear stability analysis [M. Plapp and A. Karma, Phys. Rev. E 60, 6865 (1999)], which predicts a destabilization of the front by long-wavelength modes that may be stationary or oscillatory. A fine comparison, however, reveals that the assumption commonly attributed to Cahn that lamellae grow perpendicular to the envelope of the solidification front is weakly violated in the phase-field simulations. We show that, even though weak, this violation has an important quantitative effect on the stability properties of the eutectic front. We also investigate the dynamics of fully developed colonies and find that the large-scale envelope of the composite eutectic front does not converge to a steady state, but exhibits cell elimination and tip-splitting events up to the largest times simulated.

Aerosol formation during PARFORCE: Ternary nucleation of H2SO4, NH3, and H2O

Abstract: [1] A new version of a ternary nucleation (sulphuric acid-ammonia-water) model based on classical nucleation theory, but with an improved ability to predict nucleation rates over a larger temperature range (258–303 K) compared with previous work, is presented. The modeled nucleation rates are given as a function of temperature and ambient acid and ammonia concentrations. For the first time the predicted ternary nucleation rates are compared to the observed particle production rates using measured ambient sulphuric acid and ammonia concentrations as input data. The ambient gas concentrations were measured simultaneously to aerosol formation rates during the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) coastal field campaign at Mace Head. According to the results, daytime ambient acid and ammonia concentrations were significantly higher than required by model calculations to induce the formation of new particles by homogeneous ternary nucleation. However, binary nucleation of sulphuric acid-water molecules is not able to predict new particle formation since the binary nucleation rate is far too small. We conclude that all particle formation events observed at coastal sites can be initiated by ternary nucleation of sulphuric acid, ammonia, and water vapor. However, related studies illustrate that ambient sulphuric acid concentrations are, nevertheless, insufficient to explain observed rapid growth of particles from 1 to 3 nm sizes which can be detected by current instrumentation. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0322 Atmospheric Composition and Structure: Constituent sources and sinks; KEYWORDS: water, sulfuric acid, ammonia, nucleation

Temperature dependence of flexural strength and microstructure of Al2O3/Y3Al5O12/ZrO2 ternary melt growth composites

Abstract: New Al2O3/Y3Al5O12(YAG)/ZrO2 ternary Melt Growth Composites (MGCs) with a novel microstructure have been fabricated by unidirectional solidification. These MGCs displayed superior high-temperature strength characteristics. The flexural strength increases progressively in the range 650–800 MPa with a rise in temperature from room temperature up to 1873 K. These excellent high-temperature characteristics are closely linked to such factors as: a microstructure consisting of three-dimensionally continuous and complexly entangled single-crystal Al2O3 with a hexagonal structure, single-crystal YAG with a garnet structure and fine ZrO2 with a cubic structure; characteristic dimensions of the microstructure of Al2O3/YAG/ZrO2 ternary eutectic ceramics of around 2–3 μm for YAG, around 2–3 μm for Al2O3 and around 0.4–0.8 μm for ZrO2; and the fact that no amorphous phase is formed at interfaces between any of the phases.

Measurements and modeling of the phase behavior of ternary systems of interest for the GAS process: I. The system carbon dioxide+1-propanol+salicylic acid

Abstract: As a representative model system for the gas-anti-solvent (GAS) process, the phase behavior of the ternary system carbon dioxide+1-propanol+salicylic acid has been studied experimentally. For this purpose, carbon dioxide has been chosen as the anti-solvent gas, 1-propanol as the organic solvent, and salicylic acid (2-hydroxy benzoic acid) as the model drug. In each experiment, a solution of salicylic acid in 1-propanol was expanded using carbon dioxide as the anti-solvent. A synthetic method was used for measuring bubble point curves, and the solid (salicylic acid)–liquid boundaries. Three-phase equilibrium data solid (salicylic acid)–liquid–vapor were obtained from intersection of two-phase isopleths vapor–liquid and solid–liquid. Results are reported for this ternary system at carbon dioxide concentrations ranging from 8.0 to 90.6 mol%, and within temperature and pressure ranges of 273–367 K and 1.0–12.5 MPa, respectively. It has been observed that the carbon dioxide concentration significantly affects the optimum operational conditions of the GAS process, i.e. at lower concentrations carbon dioxide acts as a co-solvent, while at higher concentrations it acts as an anti-solvent. Also, it is shown that at a proper temperature, it is possible to precipitate most of the dissolved solute with only a small change of the pressure. The Peng–Robinson equation of state as modified by Stryjek and Vera (PRSV EOS) has been used to model the ternary system.

Ternary and quarternary nanocrystals, processes for their production and uses thereof

Abstract: The present invention relates to nanocrystals consisting of a homogeneous ternary or quaternary alloy having the composition M11-xM2xAyB1-y, respectively, a process for its production, as well as to uses of such nonocrystals such as short wavelength light-emitting devices, and in the detection of analytes, in particular biomolecules.

Structure of Lithium Nitride and Transition-Metal-Doped Derivatives, Li3-x-yMxN (M = Ni, Cu): A Powder Neutron Diffraction Study

Abstract: Structures of lithium nitride (α-Li3N) and ternary nitridometalates Li3-x-yMxN (M = Ni, Cu) have been refined from time-of-flight powder neutron diffraction data using the Rietveld method. The parent binary nitride was synthesized by reaction of lithium metal with nitrogen using liquid sodium as a solvent. The ternary nitrides were prepared by reaction of Li3N with the respective transition metals under nitrogen. Refined data confirm the hexagonal structure previously reported by single-crystal X-ray diffraction for lithium nitride (P6/mmm, a = 3.6576(1) A, c = 3.8735(1) A, Z = 1) and show that the α-Li3N phase contains close to 3% Li vacancies at room temperature. The substituted nitridometalates, Li1.36Ni0.79N and Li2.21Cu0.40N, both form structures analogous to α-Li3N (P6/mmm, a = 3.7697(1) A, c = 3.5270(1) A and a = 3.6791(1) A, c = 3.7725(1) A, respectively) in which the transition metal is disordered with Li between [Li2-yN] planes and Li vacancies are disordered within these planes. The nickel and ...

Phase equilibria in Fe-Cu-X (X: Co, Cr, Si, V) ternary systems

Abstract: Phase equilibria on the Fe-Cu side in the Fe-Cu-X (X: Co, Cr, Si, V) system were experimentally determined over the temperature range of 1073–1273 K. Based on the present results and previous works, the thermodynamic assessments of the phase equilibria in the Fe-Cu-X system were evaluated using the Calculation of Phase Diagram (CALPHAD) method. The Gibbs energies (G) of the bcc, fcc, and liquid phases are described by the subregular solution model, and a set of thermodynamic parameters enable us to calculate various isothermal and vertical sections and the miscibility gaps of the solid and liquid phases.

Theory of the ternary layered system Ti-Al-N

Abstract: We present calculations on the physical properties of Ti4AlN3 obtained from first principles, as well as some general observations concerning this group of materials. We further report mechanical data obtained through numerical simulations for some representative phases, and elaborate on the issue of high pressure stability. By examining the density of states of Ti4AlN3, we conclude that it is a semimetal, and we predict an opening up of the band gap around the Fermi level with increasing pressure.

Preparation and properties of nano‐Al2O3 particles/polyester/epoxy resin ternary composites

Abstract: This article presents the results of an experimental study on the preparation and properties of new ternary composites composed of nano-Al2O3 particles, polyester, and epoxy resin. The ternary composites were prepared by the addition of the nano-Al2O3 particles in a binary matrix, with elevated viscosity, of the epoxy resin modified by the polyester. The nano-Al2O3 particles were previously located and dispersed in the polyester phase. The study showed that the ternary system was a type of nanoscale dispersed composite with high strength and toughness as well as modulus, combined with excellent dielectric and heat-resistance properties. All related properties of the composites were remarkably superior to those of both the binary matrix and the unmodified epoxy resin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 70–77, 2002

Aerosol formation during PARFORCE: Ternary nucleation of H2SO4, NH3, and H2O : New Particle Formation and Fate in the Coastal Environment (PARFORCE)

Abstract: A new version of a ternary nucleation (sulphuric acid-ammonia-water) model based on classical nucleation theory, but with an improved ability to predict nucleation rates over a larger temperature range (258-303 K) compared with previous work, is presented. The modeled nucleation rates are given as a function of temperature and ambient acid and ammonia concentrations. For the first time the predicted ternary nucleation rates are compared to the observed particle production rates using measured ambient sulphuric acid and ammonia concentrations as input data. The ambient gas concentrations were measured simultaneously to aerosol formation rates during the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) coastal field campaign at Mace Head. According to the results, daytime ambient acid and ammonia concentrations were significantly higher than required by model calculations to induce the formation of new particles by homogeneous ternary nucleation. However, binary nucleation of sulphuric acid-water molecules is not able to predict new particle formation since the binary nucleation rate is far too small. We conclude that all particle formation events observed at coastal sites can be initiated by ternary nucleation of sulphuric acid, ammonia, and water vapor. However, related studies illustrate that ambient sulphuric acid concentrations are, nevertheless, insufficient to explain observed rapid growth of particles from 1 to 3 nm sizes which can be detected by current instrumentation.