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  • Author or Editor: Keung Park x
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Abstract  

Brief history and current status of activation analysis in Korea are described. About 120 papers have been published since the first paper was reported in 1960. They are sorted out into 5 consecutive periods according to the publication year, and typical feature of each period is described.

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Abstract  

A Peak Identification and Activity Determination (PIAD) computer program has been developed. A new concept of peak significance is introduced and a great change has been made to the currently used associated gamma lines technique in calculating the confidence index; confidence factor is also given to the gamma line of a nuclide that is not seen in the spectrum. The program is written in Fortran IV under the operating system of RSX-11M.

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Abstract  

The loss of trace elements during NAA of five liquid reagents, hydrofluoric acid, hydrochloric acid, nitric acid, hydrogen peroxide and deioniyed water, has been investigated using 17 radioactive tracers of46Sc,51Cr,54Mn,59Fe,60Co,645Zn,75Se,85Sr,95Zr,113Sn,124Sb,151Eu,160Yb,177Lu,182Ta,233Pa. Two kinds of container quartz and polyethylene have been used for irradiation and also for preconcentration of the reagents. The containers were cleaned before use by washing-leaching-rinsing procedure. The reagents were preconcentrated by subboiling evaporation under the infrared lamp in clean bench. The loss of trace elements has been revealed to be severer for the reagents of hydrochloric acid and nitric acid in the container of quartz than for the other cases, while that is lowest for hydrogen peroxide.

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Abstract  

The adsorption characteristics of carbon on a strong base anion and cation exchange mixed resin, Amberlite IRN-150 in OH+ and H (1∶1) used in nuclear power plant, were investigated at 6, 30 and 50 °C at a concentration of carbon up to 0.02M. The expression for the adsorption of carbon was well fitted to the Freundlich equation and the constants,k andn in the equation were deduced. Furthermore, we could explain that the adsorption capacity on the mixed resin increases with temperature.

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Abstract  

The manganese sulphate bath method is widely used for measurements of neutron source strength. In this study, the analytical chemistry method based on the Inductively Coupled Plasma (ICP) spectrometry was used for examining the impurity contents of MnSO4·H2O, to induce55Mn(n,γ)56Mn reactions. From the analytical results, mainly K, Co, and Zn as well as trace amounts of Cd, Li, etc., have turned out to be the relevant impurities absorbing the neutrons and the fraction of neutron absorbed by the total impurities was determined to be 1.37%.

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Abstract  

The mechanism of the reduction reaction of lanthanide(III) ions by hydrated electrons in polar solvents has been investigated. The theoretical rate constants for the reaction of hydrated electrons with a number of lanthanide ions have been calculated using the energy gap laws of the charge shift reaction(D+−A→D−A+) and compared with experimental values. With these results, we have explained the large difference of the reaction rates of lanthanide ions with hydrated electrons, which depend upon the kind of lanthanide ion. The calculated results agree almost quantitatively with the experimental values.

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Abstract  

A radiochemical separation method using an anion exchange resin has been applied to 4N grade tungsten for determining U, Th and 4 other elements. While tungsten remained in the resin, Na, K and As were separated with 0.05M HCl and 1M HF and then U, Th and Cr were eluted with 1M HCl and 1M HF. The separation yield of neptunium (U) was influenced largely by the amount of thorium, but this influence could be neglected as the concentration of the thorium was below 0.5g/ml. The content of these elements were calculated by a single comparator method using monitors, gold and cobalt. The detection limits of U and Th are 4.0 and 1.2 ppb, respectively.

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Abstract  

A radiochemical separation method has been applied for determining uranium, thorium and other impurities in molybdenum metallic powder. The impurities of Na, K, Sm, Cr, Zr, Cs, Rb, Zn, Fe, Co and La were separated with a cation exchange resin, and uranium and thorium were, then, separated with an anion exchange resin. The content of impurities were determined by a single comparator method using two monitors, gold and cobalt.

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Abstract  

For the separation of rare-earth elements from steel, with a cation exchange resin, separation experiments were performed on NIST reference materials of SRM-363 and SRM-364. Iron, Na, Cr, Mn, Co, Cu, As, Mo, Sb and W were separated in 2M hydrochloric acid, five rare-earth elements, La, Ce, Pr, Nd and Sm and three other elements, Hf, Zr and Ba were separated using 8M nitric acid. Each element was determined by a single comparator method using two monitors, gold and cobalt.

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