Chou Model Research Articles

Surface tension calculation of the Sn–Ga–In ternary alloy

Surface tensions of the Sn–Ga–In ternary alloy are calculated from the surface tensions of the Sn–Ga, Ga–In and In–Sn sub-binary systems by using geometric models (the Kohler model and the Toop model), and a general solution model (the Chou model). The calculated results are in excellent agreement with the experimental data (except for the Kohler model), assuming an experimental accuracy of ±2.5%. At the same time, the surface tensions of the Sn–Ga–In ternary alloy at 773 K and their sub-binary systems are predicted on the basis of Butler’s equation, in combination with thermodynamic data, and different model parameters β equal to the ratio of the coordination number in the surface phase to that in the bulk phase. Different values of β have almost no influence on the surface tensions. The predicted results agree with the experimental data. Therefore, the resulting iso-surface tension curves for the Sn–Ga–In ternary alloy at 773 K, especially those calculated by using the Toop model, are reasonable.

Thermodynamic calculation of intermetallic compounds in AZ91 alloy containing calcium

Based on the Miedema model and Chou model, the activities of different solute components in Mg-Al-Zn, Mg-Ca-Zn and Mg-Al-Ca ternary systems were calculated. The results show that the variety of zinc content has little influence on the activity of Al or Ca, and the interaction of Zn and Al or Ca can be neglected when the mass fraction of Zn is lower than 2% in the AZ91 alloy containing calcium (noted as Mg-Al-Zn-Ca system). Therefore, the possible intermetallic compounds in the Mg-Al-Zn-Ca system can be predicted by directly calculating the Gibbs free energies of the reactions in Mg-Al-Ca system. The calculated Gibbs free energies in the Mg-Al-Ca system indicate that Al 2Ca phase can take priority of depositing, which agrees with the experimental results in references. The consistency of calculation and experiment proves that the intermetallic compounds in the Mg-Al-Zn-Ca system can be predicted by the Miedema model and Chou model.

Surface tension calculation of the Ni 3S 2FeSCu 2S mattes

The surface tension of the Ni 3S 2-FeS-Cu 2S ternary mattes have been calculated from those of the Ni 3S 2-FeS·FeS-Cu 2S and Cu 2S-Ni 3S 2 pseudo-binary boundary systems by using geometric models (Kohler and Toop model) and a general solution model (Chou model). Taking account of the experimental accuracy of ±2.5%, the respective calculated results are in agreement with the experimental data. At the same time, surface tensions of molten Ni 3S 2-FeS-Cu 2S mattes and their pseudo-binary boundary systems are predicted based on Butler's original treatment with great attention to the model parameter β. The predicted results also agree with the experimental data. Therefore, the resulting iso-surface tension curves in molten Ni 3S 2-FeS-Cu 2S mattes at 1473K, especially calculated by using Kohler, Toop and Chou models, are generally acceptable.

Interface between fluid- and solid-like behaviour in rapid granular flows down bumpy inclines

Gravity-driven granular flows down bumpy inclined surfaces were investigated. The flows consist of a bottom region of an amorphous solid-like granular material interacting with a top region of rapidly agitated grains. Chou theoretically analysed these granular flows by employing the constitutive theory, the corresponding boundary conditions and the continuity conditions at the interface. By making use of Chou's model, the research work reported here investigated the effects of the inclination, coefficient of restitution and boundary geometry on the profiles of solid concentration, mean velocity and granular temperature. The direction of the energy flux at the bumpy surfaces, as well as the flow depth for both the active and passive layers were also observed.

Comparative study of thermodynamic predicting methods applied to the Pb–Zn–Ag system

Results of thermodynamic predicting methods applied to the ternary Pb–Zn–Ag system are presented in this paper. The Chou's model has been used to predict the thermodynamic properties of the investigated system, while the other traditional models such as Toop, Hillert, Kohler and Muggianu are also included in calculations for comparison and discussion. The calculated data could be useful in further interpretation of the phenomena occurring in the Parkes process of desilverizing in the extractive metallurgy of lead.

A Collisional Model of the Positive Ion Collection by a Cylindrical Langmuir Probe

AbstractThis article presents a new theoretical model of ion collection by a cylindrical Langmuir probe at medium and higher pressures which we call the “modified Talbot and Chou model”. The model makes use of the following theories; (a) the kinetic theory by Chou, Talbot and Willis [6, 7] and (b) the theory by Zakrzewski and Kopiczynski [10, 11]. The basic idea is to calculate the decrease of probe ion current due to collisions with neutrals according [6, 7] and the increase of the ion current due to destruction of an orbital motion according [10, 11]. The computed results are presented in the form of graphs suitable for probe data interpretation at medium and higher pressures. The applicability of the results at particular plasma conditions is also discussed.

Diffusion‐Controlled Reactions of Enzymes

In the study of enzyme-catalysed mechanisms, it is often necessary to calculate the upper limit of enzyme reaction, which is usually used as an important criterion to identify whether an assumed enzyme-catalysed mechanism is reasonable or not. Basically, in the existing methods, there are two kinds of models, the Alberty-Hammes-Eigen model and the Chou model, for calculating the upper limit of enzyme reaction. In this paper, an analysis and comparison between these two models are made. It is pointed out that the magnitude of the van der Waals' binding energy between enzyme and substrate molecules will play a key role in deciding whether there is a significant difference or not for the results calculated from these two models. Through such a comparison, the role of the major protein outside the active site of an enzyme molecule also becomes obvious; if the van der Waals' binding energy is very small, the major protein will act like a 'wall', blocking the flow of some substrate molecules to the active site; while if the van der Waals' energy is greater than 3 kT (where k is the Boltzmann constant and T the absolute temperature), the major protein will behave like a 'accelerator', speeding up the flow of the substrate molecules to the active site around the enzyme molecule.

Operator form of the droplet model and neutral currents

The quantized version of Chou and Yang's droplet model, which has been successfully applied to electromagnetic and strong diffractive scattering, is applied here to weak-neutral-current elastic scattering. Divergences can be avoided and the cross-sections approach constant values at asymptotic energies.