Ternary Matrix Research Articles

Formation, structure, and phonon confinement effect of nanocrystalline Si1−xGex in SiO2-Si-Ge cosputtered films

Using magnetron cosputtering of SiO2, Ge, and Si targets, Si-based SiO2:Ge:Si films were fabricated for exploring the influence of Si target proportion (PSi) and annealing temperature (Ta) on formation, local structure, and phonon properties of nanocrystalline Si1−xGex (nc-Si1−xGex). At low PSi and Ta higher than 800°C, no nc-Si1−xGex but a kind of composite nanocrystal consisting of a Ge core, GeSi shell, and amorphous Si outer shell is formed in the SiO2 matrix. At moderate PSi, nc-Si1−xGex begins to be formed at Ta=800°C and coexists with nc-Ge at Ta=1100°C. At high PSi, it was disclosed that both optical phonon frequency and lattice spacing of nc-Si1−xGex increase with raising Ta. The possible origin of this phenomenon is discussed by considering three factors, the phonon confinement, strain effect, and composition variation of nc-Si1−xGex. This work will be helpful in understanding the growth process of ternary GeSiO films and beneficial to further investigations on optical properties of nc-Ge1−xSix in the ternary matrix.

An algorithm for generating cation exchange isotherms from binary selectivity coefficients

An algorithm for simulating ion exchange batch mode experiments utilizing a known binary or ternary linear or nonlinear selectivity matrix and disequilibrium concentrations in exchange and solution phases was developed, and can be used to calculate initial equilibrium conditions for the initiation of numerical transport simulations, to generate binary isotherms (by repeated applications), and to separate ion‐exchange from other solute reactions in soils. The algorithm is an iterative process utilizing a binary search to determine the sorbed phase concentrations defined by the selectivity values and dissolved phase concentrations while maintaining the correct total mass of all ions. It was developed to aid in the separation of ion‐exchange from other retention processes when empirical determination of exchange isotherms are difficult or impossible.

Elastic Behaviour of Ternary Rubber-filled Vulcanizates

Near-equilibrium stress–strain measurements have been carried out on ternary rubber vulcanizates. The effect of variation of the butyl rubber content on the elastic behaviour of the ternary rubber vulcanizates has been studied. It has been found that butyl rubber (IIR) is less sensitive to the vulcanization system used than either natural rubber (NR) or styrene–butadiene rubber (SBR). One can obtain a partially crosslinked system with an IIR phase embedded in the crosslinked matrix of NR and SBR. The role played by carbon black during mixing of the ternary blend has been investigated. The Mooney–Rivlin relationship was used to describe the behaviour of the ternary rubber matrix. The constants 2C1 and 2C2 have been calculated by use of the strain-amplification factor and the total crosslink density of the ternary rubber–carbon black systems has been investigated. The data have been evaluated in terms of the molecular theories of rubber elasticity. The elastic behaviour was found to be intermediate between the affine and phantom limits of the theory. © of SCI.

Reconfirmation of the existence of δ2 in dental amalgams

The ∼90°C endotherm peak in the thermogram of a conventional dental amalgam is due to two overlapping peritectic transitions involving SnHg-δ2 and HgAgSn-γ1, respectively. The aim of the present study is to separate these two events and thus confirm that the δ2 phase is indeed a part of an amalgam microstructure. The materials used in this study were: sample 1, γ1+1 wt% Sn; sample 2, γ1+2 wt% Sn; sample 3, γ1+3 wt% Sn; and sample 4, a commercial conventional amalgam with 48 wt% Hg. In powder form, they were exposed to 1 wt% NaCl solution at 37 °C for up to 45 days. At 15 day intervals, samples were withdrawn from the solution, washed, dried and then characterized by the differential scanning calorimetry (DSC) technique. Corrosion of Sn from ternary γ1 matrix and intergranular δ2 in respective materials during their exposure to the NaCl solution led to the following: (a) a progressive increase in γ1→β1 transition temperature in samples 1 and 2; (b) a gradual decrease in δ2 peak and its disappearance in sample 2; and (c) in samples 3 and 4, initial splitting of the ∼90°C peak into two distinct endotherms associated with δ2 and γ1, respectively. Continued corrosion of the last two materials produced further changes in δ2 and γ1 in a manner similar to that seen in samples 1 and 2. On the basis of these observations, we have concluded that the ∼90°C endotherm is a valid indicator of the existence of the δ2 phase in dental amalgams.

The matrix phase of a ductile dental amalgam

In this study, the ternary HgAgSn-γ1 matrix of a ductile dental amalgam has been characterized and compared with that of a brittle amalgam. Specimens of both amalgams were prepared form commercial alloy powders according to the ADA specification 1, stored at 37°C and studied by differential scanning calorimetry technique at timed intervals up to 1 year. Experimental amalgams of AgCu eutectic admixed with varying concentrations of Sn were used as standards. The matrix of the ductile amalgam was found to contain two substructures initially. One was saturated with Sn and the other contained lesser amounts of Sn. These substructures disappeared with time leading to a matrix in which Sn was well below its saturation limit but uniformly distributed. The matrix of the brittle amalgam, on the other hand, was saturated with Sn during the entire period of this study.

Infrared profile of van der Waals dimers HCl–RG* (RG*=Ar, Kr, Xe) trapped in rare gas matrices

The infrared profile of the van der Waals dimers HCl–RG* trapped in a ternary matrix containing small molar ratio of hydracids (≤1/1000) and of rare gas dopants (≂1/10) is theoretically investigated. The homogeneous profile of a single dimer is determined, using a conventional cumulant expansion of the coupling Hamiltonian between a renormalized optical system described by the vibration-orientation Hamiltonian of the trapped molecule and a renormalized bath defined by the lattice modes and the molecule and dopant center of mass motions. The influence of the ternary matrix inhomogeneities is also studied within the framework of a stochastic model which describes the interaction between the various species in the solid. A detailed analysis of the homogeneous and inhomogeneous broadenings of the infrared lines of these dimers is done on the basis of relatively accurate interaction potentials, previously determined. The comparison of the infrared profiles with recent FTIR spectroscopic data shows a fair agreement in most cases.

Ternary dissolution kinetics in the Fe-Ni-P system

The dissolution of (FeNi)3P in the ternary Fe-Ni-P system has been studied by optical and electron microprobe techniques. Precipitates of (FeNi)3P, initially in equilibrium with their ternary matrix (a at 750°C, y at 875°C), were examined after being partially dissolved by heating at 975°C. In addition, diffusion couples with starting compositions similar to the equilibrated ternary alloys were examined after also being heat treated at 975°C. Phosphide, (FeNi)3P, dissolution in the α or γ phase is diffusion controlled at 975°C. The ternary dissolution paths observed in each of the diffusion couples are unique and the same as those observed in the comparable alloys. The dissolution rate of (FeNi)3P is controlled by the diffusion rate of P in the α or y phases. The Ni interface compositions in (FeNi)3P and α or γ and the dissolution path through the ternary are determined by the rate of dissolution and the major Ni ternary diffusion coefficients. It is possible to calculate both the dissolution path and rate for (FeNi)3P by using the binary dissolution equations in combination with the Fe-Ni-P diagram and the major (ternary) diffusion coefficients. In addition, numerical solutions can be correctly calculated for diffusion controlled dissolution where impingement of overlapping gradients occurs.

Stability of metal base composite materials

1. In an investigation into the structural stability of tungsten fibers in the ternary system Ni-Cr-W, a study was made of the kinetics of tungsten fiber dissolution in ternary matrix alloys of various compositions. 2. It is shown that no fiber dissolution occurs in matrices whose compositions are located close to the limited solubility line for the temperature under consideration.

Automatization of the Logical Synthesis of Discrete Automata

The system described in this paper represents a set of several hundreds of programs expressed in the LYaPAS algoritmical language and realizable with the help of an automatic programming system having the same name. These programs solve logical problems of different kinds arising with the synthesis of discrete automata and form a hierarchy at the lower levels of which are located programs for solving the simplest logical and combinatorial problems; at the middle levels are programs for solving problems of the different sections of discrete mathematics; at the top levels are programs for “through-synthesis” of discrete automatic devices of certain classes.General principles of organization of both system of automatic synthesis and the system of automatic programming employed by it have been expounded. Examples of original algorithms from the system are given which are solving problems of finding the shortest cover of a Boolean matrix, the analysis of a ternary matrix as to singularity, the finding of the core in a non-redundant disjunctive normal form of a Boolean function, the finding of the simple Quine matrix etc.