DSpace collection: 17期 (1991)
https://ir.cnu.edu.tw/handle/310902800/23464
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A New Steroidal Glycoside, Cynanformoside C, Form the Aerial Part of Cynanchym Formosanum
https://ir.cnu.edu.tw/handle/310902800/23484
title: A New Steroidal Glycoside, Cynanformoside C, Form the Aerial Part of Cynanchym Formosanum abstract: A new glycoside, cynanformoside C, has been isolated from the aerial part of Cynanchum formosanum. The structure of the new compound has been elucidated by spectroscopic and chemical methods.
<br>Cadmium Transport in Soil: Model and Experiments
https://ir.cnu.edu.tw/handle/310902800/23483
title: Cadmium Transport in Soil: Model and Experiments abstract: The main mechanisms involved in Cd transport in satruated subsurface soil was studied by modelling it as a fixed bed adsorption system. Experiments conducted with ditterent particle sizes of sand (and at pH 6.0) indicated that isotherm parameters depend on sand particle size. Freundlich isotherm gave better correlation for adsorption of Cd in sand medium than Langmuir isotherm. The applicability of relative solute velocity transport model derived from general solute transport equation, incorporating Freundlich isotherm (with local equilibrium assumption) was investigated. The relative solute velocity predicted from batch experimental data was higher than that of soil column breakthrough data, thus isotherm parameters estimated from the column breakthrough were used in model simulation. The relative Cd velocities (to Darcy's velocity)were found to be in the range of 0.0008 to 0.001., indicating limited mobility under the conditions tested.
<br>Solute Transport Through Unsaturated Soils: A Simple Equilibrium Adsorption Model
https://ir.cnu.edu.tw/handle/310902800/23482
title: Solute Transport Through Unsaturated Soils: A Simple Equilibrium Adsorption Model abstract: Anon-linear equilibrium adsorption model wasapplied to predict the movementot solutes through unsatruated soils. All parameters such as water contenet (θ), hydraulic conductivity (K), soilwater diffusivity (D), dispersion coefficient (D.), pore velocity (v) were treated as variables and the latter four also as functions of θ. Water content and solute concentration profiles were predicted with this model assumes the experimental conditions of Elrick et al. (1979) in which KCl was the solute and Brookstonclay loam the soil. Good agreement was found with experimental and predicted water content profileseven though curve fitting was not used in this case. For the solute concentratlon profiles only one parameter,I was varied to fit the experimental data. The best-fit value for I was found to be well wlthin acceptable limits. Although only first order approximations were used the effect of numerical dispersion was not accounte dispersion was not accounted for in the solution since tne value of D., was found not to be significant due to the low pore water velocity in the nusaturated case. Fairly sharp fronts were obtained for the solute concentration profile indicating low dispersion in the unsaturated case.
<br>Technical note Ionic strength in deep bed filtration
https://ir.cnu.edu.tw/handle/310902800/23481
title: Technical note Ionic strength in deep bed filtration abstract: The removal efficiency of particlcs in deep bed filtration depends on both transport and attachment mechanisms of particles. The particle attachment mechanisms depend mainly on chemical characteristics of aqueous phase, suspended particles and filter media. In this study, two different suspensions were used to study the effect of ionic strength on the particle removal efficiency. The ionic strength of suspensins was varied by adding a known amount of sodium chloride. The removal efficiencies were related to ionic strength and zeta potentail. The clean filter bed efficiency and removal efficiency during the ripening period for various strengths were quantitatively related to the two model coefficients iuring the ripcning pcriod l`vr various strcngths werc quantitativcly relalcd to thc two model coethcicnls appering in the O'Melia-Ali model. These model coefficients represent the filter medium-particle and particle-particle attachments. This type of quantificaton of the effect of ionic strength in terms of filter efficiency is very useful in filter design and operation control.
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