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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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Author: search.filters.author.CHEN, JSHas files: Yes

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Now showing 1 - 6 of 6
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    CALCULATION OF LAG TIME FOR CONVECTIVE-REACTIVE DIFFUSION
    (1991-11-28)
    CHEN, JS
    ;
    ROSENBERGER, F
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    Closed form solutions for the steady-state permeability P and the lag time L of a linear diffusion system with concurrent convection and reaction were obtained by two methods. In the first method, we identify the singularity at s = 0 of the Laplace transform of the total amount of diffusant, Q(s), released into the receiver as representation of the asymptotic diffusion behavior. P and L are then obtained from the time-independent coefficients of an expansion of Q(s) about s = 0. In the second method, we transform the convective-reactive diffusion equation into a form that contains only first and second derivatives of the concentration distribution function. By comparison of the resulting equation with that for a heterogeneous diffusion system, relationships of the convection velocity and rate constant with the position-dependent partition coefficient in heterogeneous diffusion is found. Taking advantage of the known solutions for permeabiliy and lag time in heterogeneous diffusion, the corresponding expressions for P and L in convective-reactive diffusion are then obtained by transcription. These methods have the advantage over earlier approaches in that solutions in an infinite form are avoided.
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    THEORY OF THE TIME-LAG DIFFUSION METHOD FOR THE CASE OF AN OUTGASSING SOLID
    (1993-06-01)
    BAIRD, JK
    ;
    CHEN, JS
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    In the ordinary application of the time-lag method to the measurement of the diffusion coefficient of a gas passing through a plane sheet of an inert solid, the gas is pressurized on one side of the sheet and evacuated on the other. After decay of transients, the cumulative amount, Q(t), of gas diffused through the sheet in time, t, assumes the ''time-lag'' form, Q(t) = A(t - L). Measurements of the slope, A, and the intercept, L, can be used to determine the diffusion coefficient and the solubility of the gas in the solid. We have rederived this law for the case of a solid that is actively evolving this same gas at an arbitrary rate and have used it to predict the rate of outgassing of the solid upon standing. Practical applications of the theory include radioactive decay of minerals, rejection of plasticizers by plastics, and the decomposition of solid rocket propellants.
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    GRAPHIC METHOD FOR THE DETERMINATION OF THE COMPLEX NMR SHIFT AND EQUILIBRIUM-CONSTANT FOR A HETERO-ASSOCIATION ACCOMPANYING A SELF-ASSOCIATION
    (1994-02-07)
    CHEN, JS
    ;
    SHIAO, JC
    ;
    交大名義發表
    ;
    應用化學系
    ;
    National Chiao Tung University
    A novel graphic method to determine the complex shift and equilibrium constant for a hetero-association, A + B reversible arrow AB, accompanying a self-association A + A reversible arrow A(2), has been described. The method is to be used in conjunction with a graphic determination of the monomer shift, dimer shift and dimerization constant proposed previously. Our new method is advantageous over the conventional Benesi-Hildebrand (BH) plot in that the limitations, (1) that the concentration of one component must be much less than that of the other and (2) that self-association of species is not allowed, are completely removed. The related parameters of the self-association of 2-isopropylphenol (A) and the hetero-association of 2-isopropylphenol with acetone (B) in the inert solvent [H-2(12)]cyclohexane has been used to demonstrated the use of this new graphic method. Comparison with the results from a BH plot has also been made.
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    NMR-STUDY OF EPSILON-CAPROLACTAM IN VARIOUS SOLVENTS - GRAPHICAL DETERMINATION OF MONOMER SHIFT, DIMER SHIFT AND DIMERIZATION CONSTANT FROM THE DILUTION SHIFT DATA
    (1994-03-07)
    CHEN, JS
    ;
    交大名義發表
    ;
    應用化學系
    ;
    National Chiao Tung University
    ;
    Department of Applied Chemistry
    A graphical method for the simultaneous determination of the monomer shift, dimer shift and dimerization constant of a self-association system from the dilution NMR shift data is proposed. This method avoids the conventional extrapolation to infinite dilution to obtain the monomer shift. Three self-association systems: epsilon-caprolactam in [H-2(1)]chloroform, [H-2(3)]acetone and [H-2(3)]acetonitrile were studied at various temperatures. The enthalpy and entropy of dimerization were also determined from van't Hoff plots.
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    DIRECTIONAL SYMMETRY OF THE TIME-LAG FOR DOWNSTREAM ABSORPTIVE PERMEATION STUDIED BY THE MATRIX-METHOD
    (1994-09-21)
    CHEN, JS
    ;
    交大名義發表
    ;
    應用化學系
    ;
    National Chiao Tung University
    ;
    Department of Applied Chemistry
    The directional symmetry of the downstream time lag for absorptive permeation, accompanying a first-order reaction, across a heterogeneous membrane has been proven by the matrix method based on the theory of Siegel. Owing to the heterogeneity the partition coefficient (K), diffusivity (D) and rate constant (k) are all dependent on position. The directional symmetry was first shown for multiple laminates with each laminate having a distinct K, D and k. The transmission matrix of the system is then a sequential product of those of the individual laminates. The proof is for the unit value of the determinant of the transmission matrix for each laminate and, hence, for the whole system. Directional symmetry is thus proven for the heterogeneous membrane, since it can be visualized to be an assembly of an infinite number of infinitely thin, homogeneous laminates.
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    PERMEABILITY AND THE TIME-LAG FOR DOWNSTREAM ABSORPTIVE PERMEATION WITH CONCOMITANT REACTION ACROSS A SERIES-PARALLEL PATH STUDIED BY THE MATRIX-METHOD
    (1995-02-07)
    SHI, WG
    ;
    CHEN, JS
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    Based on Siegel's theory, the permeability (P) and the downstream time lag (t(L)) for absorptive unidirectional permeation, accompanying a first-order reaction, across a membrane composed of two parallel laminae in series with another lamina, have been calculated from the transmission matrix of the whole membrane. This matrix can be constructed from the transmission matrix of each component lamina. The transmission matrix of the whole membrane is first calculated from the matrices of the component laminae in the Laplace domain. P and t(L) are then derived from the first row and second column of the transmission matrix of the whole membrane according to Siegel's theory. Thus, P and t(L) can be represented in terms of the elements of the transmission matrix, and hence the diffusion parameters, of each component lamina. The directional symmetry of t(L) is also proven, based on the unity value of the determinant of the transmission matrix. The advantage of the matrix method is also discussed.