• Analytical Science and Technology
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• v.16 no.5
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• pp.418-425
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• 2003

Inorganic elemental content of bottom ash generated from municipal solid waste incinerator was determined by neutron activation analysis. Bottom ash samples were collected monthly from incinerator located in city D, strained out by the 5 mm sieve, dried by oven and pulverized by agate mortar. The samples were irradiated at NAA #1 irradiation hole in HANARO research reactor of Korea Atomic Energy Research Institute and the irradiated samples were measured by HPGe-gamma-ray spectrometer. From the activity of measured nuclides, 33 elements including As, Cr, Cu, Fe, Mn, Sb and Zn were determined applying activity creation formula and nuclear data. The quality control was conducted by simultaneous analysis with NIST standard reference materials.

• Korean Journal of Food Science and Technology
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• v.4 no.4
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• pp.300-308
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• 1972

For the purpose of utilizing agricultural waste products for animal feeds, chemical analysis of some important agricultural wastes in Korea and enzymatic hydrolysis of rice hull were undertaken and summarized as follows: 1) Rice hull and straws of rice, barley and wheat were analyzed for their proximate principles and carbohydrate composition. 2) A strain of Aspergillus niger was selected as having the highest productivity of rice hull decomposing activity among many species of molds. The optimum conditions for the culture on washed wheat bran were. 3 days of culture period, 55% moisture content and neutral pH and one hour was proper for the extraction of enzymes. 3) The extent of hydrolysis of xylan and rice hull by a crude enzyme preparation from this strain was 63% and 7%, respectively, and the optimum pH for its activity was 4.0 and 4.5, respectively. 4) Enzymatic hydrolysis of rice hull was generally suppressed by gamma-ray irradiation ($0.5{\sim}5\;Mrad$, in dry state), but the effect was less by irradiation in wet state.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.1055-1061
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• 2007

Caesalpinia sappan L. is an indeciduous tree distributed in China, India, Miyanmar and Vietnam. Its heartwood has long been used in oriental folk medicines to treat diseases. In this study, antioxidative activities of Caesalpinia sappan L. and the effect of gamma irradiation on its chemical and biological properties were investigated. The ethyl acetate fraction (EtOAc fr.) of Caesalpinia sappan L. was irradiated with 100 kGy of gamma ray. The dark red color of EtOAc fr. was significantly (p<0.05) removed by irradiation (Hunter L and b values increased and a value decreased). The total phenolic content of EtOAc fr. was 865 mg/g and it was increased to 1195 mg/g by gamma irradiation. DPPH radical and superoxide anion radical scavenging activities and lipid peroxidation inhibitory activity of EtOAc fr. were very high and its activities were also increased by gamma irradiation. EtOAc fr. also inhibited the irradiation-induced DNA damage of lymphocyte as determined by comet assay. In conclusion, EtOAc fr. of Caesalpinia sappan L. extract showed high antioxidative activities in vitro. Furthermore, gamma irradiation on EtOAc fr. ameliorated the color and antioxidative properties. Therefore, it can be suggested that Caesalpinia sappan L. may be a good material for antioxidant function and gamma irradiation may be applied for the improvement of chemical and biological properties of Caesalpinia sappan L.

• Journal of the Korean Society of Radiology
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• v.8 no.6
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• pp.293-299
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• 2014

Compton suppression device is a device by using the Compton scattering reaction and suppress the Compton continuum portion of the spectrum, so can be made more clear analysis of gamma ray peak in the Compton continuum region. Measurements above background occurs or, radioactivity counts of radioactivity concentration value of $^{40}K$ nuclides $^{137}Cs$ and natural radioactivity artificial radioactivity detected from the surface soil sample, unwanted non-target analysis and interference peak who dotted line you know the calibration of the measurement energy is allowed to apply the (Compton suppression) non-suppressed spectrum inhibition spectrum and (Compton Unsuppression) the background to the measured value of the activity concentration value of the standard-ray source is detected relative to the peak of By measuring according to the different distances cause $^{137}Cs$, and comparative analysis of the Monte Carlo simulation, in order to obtain a detection capability for efficient, looking at the Compton inhibitor, as the CSF value increases with increase in the distance, more It was found that the background due to Compton continuum of the measured spectrum suppression mode Compton unrestrained mode can know that the Compton suppression many were made, using a $^{137}Cs$ is reduced.

• Journal of the Korean Society of Radiology
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• v.4 no.1
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• pp.31-35
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• 2010

Recently, the incidents of direct or indirect radiation exposure due to increase of use of radiation or radioisotope are on the increase in medical and industrial circles. If cells are irradiated, free radicals are created through biological process, and cells are directly or indirectly damaged. This research intends to explore into the effect of saponin at the level of cell (in vitro) and entity (in vivo), using red ginseng extract "saponin", as radioprotective agent. In the experiment implemented at the level of cell (in vitro), degree of cell activity was measures by adding mouse mesenchymal stem cells "C3H/10T1/2 cells" into red ginseng extract "saponin(0, 0.05, 0.2, and 0.4 g/L)", and then the optimal concentration of saponin influencing cells was calculated, in 24, 48, 72, and 96 hours after gamma irradiation at the optimal concentration of saponin, each cell survival rate was observed through XTT assay. The best time period of cultivation for the optimal activity of C3H/10T1/2 cells was as 48 hours, and the degree of optimal activity was shown at 0.05 g/L. In 48 hours after irradiation of 5 Gy to C3H/10T1/2 cells at 0.05 g/L, the degree of activity of cells increased by 10%. In the experiment implemented at the level of entity (in vivo), red ginseng extract "saponin" at a dose of 100 mg/kg/day was injected into the abdominal cavity of six-week immature mouse for two weeks. Right after the last abdominal injection, total body irradiation of gamma rays was carried out at a dose of 5 Gy and 10 Gy. And after irradiation, the blood sample was taken, and then the number of red corpuscles was counted. In result, the decrement of experimental group treated with red ginseng extract "saponin" was 2.3 times larger than that of control group. In view of the results so far achieved, it was revealed that red ginseng extract "saponin" has a radiation exposure protection effect in the experiment implemented at the level of cell (in vitro). In case of animal experiment, the decrement of number of red corpuscles decreased. Finally, it is necessary to carry out more various researches continuously.

• Journal of Soil and Groundwater Environment
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• v.14 no.2
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• pp.10-16
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• 2009

Characteristics of natural radioactivity were investigated for soils collected from seven sites of different bed rocks distributed in the Keum River area of Korea by the use of a Gamma-ray spectrometry. Specific activity (SA) and SA ratio (SAR) of typical naturally occurring radioactive nuclide such as $^{226}$Ra, $^{228}$Ac and $^{40}$K were determined for the soil samples. The SA values of $^{226}$Ra, $^{228}$Ac and $^{40}$K in 41 soils of 7 sites are 26.7-485 (74.2 ${\pm}$ 72.2), 30.9-157 (90.7 ${\pm}$ 32.7) and 203-1558 (990 ${\pm}$ 203) Bq/kg, respectively. The SA of $^{226}$Ra has very different values by the soils and the sites. Especially the SA of $^{226}$Ra in a soil sample of Ogcheon site is 485 Bq/kg while most SA of 41 soil samples are < 100 Bq/kg. SA of $^{228}$Ac has a little different values with the soils and sites, however the SA of $^{40}$K has almost constant values in all soil samples. The SAR values of $^{26}$Ra/$^{228}$Ac, $^{226}$Ra/$^{40}$K and $^{228}$Ac/$^{40}$K in 41 soils of 7 sites are 0.343-6.11 (0.865 ${\pm}$ 0.883), 0.0258-0.759 (0.0814 ${\pm}$ 0.1l17) and 0.0373-0.178 (0.0945 ${\pm}$ 0.0373), respectively. The SARs of $^{226}$Ra/$^{228}$Ac and $^{226}$Ra/$^{40}$K have very different values by the soils and the sites, however the SAR of $^{228}$Ac/$^{40}$K has a little difference by the soil and sites.

• Analytical Science and Technology
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• v.21 no.6
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• pp.474-479
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• 2008

Radioactivity of naturally occurring radioactive nuclides (NORN) such as $^{226}Ra$, $^{228}Ac$ and $^{40}K$ were investigated for surface sediments collected from Ordos, Alashan, Taklimakan deserts and Loess plateau regions in China. By a Gamma-ray spectrometry, specific activity (SA) and SA ratio (SAR) of the NORN were determined for each source region of Asian dust. Characterization of the source regions of Asian dust was performed with the SA and SAR values. SA of $^{226}Ra$ in the three desert regions have almost same values in the range of mean value 17.9~21.9 Bq/kg, however, the SA in Loess Plateau has much higher values in the mean value of 35 Bq/Kg. SA of $^{228}Ac$ in the Ordos and Alashan desert regions have almost same values in the range of mean value 27.1~27.2 Bq/kg, and those in Taklimakan desert and Loess Plateau were 31.7 and 49.0 Bq/kg, respectively. In case of 40K, the SA in all regions have similar values in the range of 636~943 Bq/kg. The mean SAR value of $^{226}Ra/^{228}Ac$ in four source regions was almost same in the range of 0.708-0.721. It is shown that relationship between $^{226}Ra$ and $^{228}Ac$ is clearly presented in the source regions. The mean SAR values of $^{226}Ra/^{40}K$, $^{228}Ac/^{40}K$ are 0.0209-0.056, 0.0287-0.0773, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.357-361
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• 2008

In this study, the antioxidant properties and physical characteristics of irradiated Sargassum siliquastrum water extract were evaluated. Samples were irradiated with $Co^{60}{\gamma}$-ray at doses ranging from 3 to 20 kGy. They were then analyzed to investigate antioxidant properties, including total phenolic compound content and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. In addition, physical properties such as viscosity and color were evaluated. The results demonstrated that total phenolic compound content and DPPH radical scavenging activity were significantly improved (p<0.05) by irradiation. In terms of physical properties, viscosity and color were reduced in the irradiated extracts as compared to non-irradiated samples. In conclusion, gamma irradiation improved the antioxidant properties of Sargassum siliquastrum water extract, improving its original weak point as a natural antioxidant when applied in the food industry.

• Journal of the Korean Chemical Society
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• v.37 no.11
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• pp.961-966
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• 1993

The determination of noble metals such as Ir, Au and Ag in the ancient coins has been studied. For the measurement of the activity of $^{192}Ir,\;^{198}Au\;and\;^{110m}Ag$, radiochemical separations including solvent extraction and ion-exchange chromatography were applied to reduce the interference of high energy ${\gamma}$-ray emitted from various radionuclides with long half-life. As a results, $10^{-11}$ g/g level of Ir could be detected and it was found that the three kinds of the detection limits, i.e., critical, detection, quantitative limit, calculated by the method proposed by Currie, were enhanced. Prior to the re-irradiation with neutron, inactive carrier was added in order to determine the recovery yield of Ir in the radiochemical separation. The average recovery yields of Ir, Au and Ag in the 5 coins were 65.3%, 98.5%, 99.5%, respectively.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2802-2811
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• 2023

In a first-of-its-kind study, terrestrial radionuclide concentrations were measured in 35 topsoil samples from the outskirts of Dhaka using HPGe gamma-ray spectrometry to assess the radiological consequences of such a vast number of brick kilns on the plant workers, general as well as dwelling environment. The range of activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K is found at 19 ± 3.04 to 38 ± 4.94, 39 ± 5.85 to 57 ± 7.41, and (430 ± 51.60 to 570 ± 68.40) Bq/kg, respectively. ²³²Th and ⁴⁰K concentrations were higher than the global averages. Bottom ash deposition in lowlands, fly ash buildup in soils, and the fallout of micro-particles are all probable causes of the elevated radioactivity levels. ¹³⁷Cs was found in the sample, which indicates the migration of ¹³⁷Cs from nuclear accidents or nuclear fallout, or the contamination of feed coal. Although the effective dose received by the general public was below the recommended dose limit but, most estimates of hazard parameters surpass their respective population weighted global averages, indicating that brick kiln workers and nearby residents are not safe due to prolonged exposures to terrestrial radiation. In addition, the soil around sampling sites is found to be unsuitable for agricultural purposes.