• Progress in Medical Physics
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• v.10 no.1
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• pp.1-7
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• 1999

In this study, the dose distributions of a $^{32}$ p uniform cylindrical volume source and a surface source, a pure $\beta$emitter, were calculated in order to obtain information relevant to the utilization of a balloon catheter and a radioactive stent. The dose distributions of $^{32}$ p were calculated by means of the EGS4 code system. The sources are considered to be distributed uniformly in the volume and on the surface in the form of a cylinder with a radius of 1.5 mm and length of 20 mm. The energy of $\beta$particles emitted is chosen at random in the $\beta$ energy spectrum evaluated by the solution of the Dirac equation for the Coulomb potential. Liquid water is used to simulate the particle transport in the human body. The dose rates in a target at a 0.5mm radial distance from the surface of cylindrical volume and surface source are 12.133 cGy/s per GBq (0.449 cGy/s per mCi, uncertainty: 1.51%) and 24.732 cGy/s per GBq (0.915 cGy/s per mCi, uncertainty: 1.01%), respectively. The dose rates in the two sources decrease with distance in both radial and axial direction. On the basis of the above results, the determined initial activities were 29.69 mCi and 1.2278 $\mu$Ci for the balloon catheter and the radioactive stent using $^{32}$ P isotope, respectively. The total absorbed dose for optimal therapeutic regimen is considered to be 20 Gy and the treatment time in the case of the balloon catheter is less than 3 min. Absorbed doses in targets placed in a radial direction for the two sources were also calculated when it expressed initial activity in a 1 mCi/ml volume activity density for the cylindrical volume source and a 0.1 mCi/cm$^2$ area activity density for the surface source. The absorbed dose distribution around the $^{32}$ P cylindrical source with different size can be easily calculated using our results when the volume activity density and area activity density for the source are known.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.343-356
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• 2016

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5 ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, $^{60}Co$ had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as $^{28}Al$ and $^{24}Na$ had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that the nuclide inventory of a spent nuclear fuel metal cask can be utilized as basic data when decommissioning of a metal cask is planned, for example, for the development of a decommissioning plan, the determination of a decommissioning method, the estimation of radiation exposure to workers engaged in decommissioning operations, the management/reuse of radioactive wastes, etc.

• The Journal of the Korean Society for Microbiology
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• v.3 no.1
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• pp.35-41
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• 1968

An outbreak of typhoid fever in Samchunpo city was surveyed and the results were summarized as follows: 1. 638 of clinical cases were detected in 17 Dongs(districts) of the city of Samchunpo,(54,064), during the epidemic period from 1st September to the end of November, 1967. 2. The morbidity rate was 1,189 per 100,000 population;(1,300 female, and 1,060 male). 3. The highest peak was reached in the third week of September and a second peak appeared at the end of September 1967. 4. The mode of infection was suspected strongly as a water-borne and the source of infection as an old public well called Gal-Dae-Saim, since the causative agent was found in close public latrine and the contaminated sewage ditch witch was connected with the well. 5. All patients and carriers were treated at their home under the supervision of local medical authorities. 6. The Gal-Dae-Saim was closed immediately on 7th October, 1967 by the order of the mayor. 7. At the end of November, 1967 when the outbreak in Samchunpo was almost ended, another small epidemic occurred in Koseong county which bordered the eastern outskirt of the city. 8. During the survey, a strain of Shigella flexneri was isolated from the sewage located three meters from Gal-Dae-Saim and also from one case. 9. It was reported by the local health center in May, 1968, that no carrier had been detected in the survey made among the persons who had had typhoid fever in 1967. Also thereafter no cases of typhoid fever were reported through October, 1968.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.30-40
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• 2009

Employing the Numata-type life form, the paper analyzed changes of plants for 4 years at the Human-made Wetlands along Boknaecheon of Juam Lake since its creation. The number of the species planted at the Human-made Wetlands along Boknaecheon of Juam Lake, which was completed in December 2002, were 15 in total including, 10 families, 13 genera, 12 species and 3 varieties. As for the three-featured life forms of the planted species, there were 6 perennial hydatophytes, recording the biggest number of species in dormancy form; species each of $R_5$, $R_3$, $R_{2-3}$ respectively in radicoid from; 20 species of geomantic dissenminule form ($D_1$) in disseminule form and erecred type(e) existed the most in growth form. With regard to the 3 features of life form identified during the final year of the monitoring that lasted 5 years after the completion of the Wetlands, the number of species and individuals was found to have increased but there was no significant change of tendency as against the composition ration(%) of life form. There were 43 species of therophytes (Th) that covered 24.29% in dormancy form, while $R_5$ was prevalent in radicoid form and $D_4$, $D_1$, and $D_{1,4}$ comprosed 77.39% of the whole disseminule form. Growth form was surveyed in the order of erected type (e), bunch type (t), temporal rosette type (pr), branch type (b) and straight rosette type (ps) and these species comprised 64.97% of the whole flora. Consequently, in case of the artificial wetlands along the Boknaecheon of Juam Lake, it turned out that the vegetation type in which pioneer species of succession, or gradually stabilized perennial vegetation favoring Wetlands because the higher dormancy form has its perennial plants' composition ratio getting, the more its succession is progressing. Even though single grained plants ($R_5$) belonging to radicoid in breeding form, succession is predicted to take place considering the fact that they actually belong to ~ plants like Phragmites japonica that form a connection on the surface of the earth. In addition, it is judged that geomantic disseminule form ($D_1$) conveyed by water and gravitational disseminule form favored by the development of waterside woody plants ($D_4$) seem to be better fit to this area in desseminule form. As for growth form, bunch type (t) is judged to become prevalent on the Wetlands while a good variety of phanerophytes will coexist on the earth due to artificial as well as natural disturbances.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.100-106
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• 2001

The objective of this study was to improve the shelf-life of kimchi by freeze drying. Kimchi was freeze dried and stored at $0^{\circ}C$, $5^{\circ}C$ and $28^{\circ}C$ for 60 days. It was reconstituted with water at an interval of ten days and number of total lactic acid bacteria(LAB), sensory properties and shape/color were observed. The results were as follows: (1) Number of total LAB of sample stored at $0^{\circ}C$ or $5^{\circ}C$ for 60 days decreased gradually and the value of 10 day-sample and 30 day-sample was significantly different from the value of 0 day-sample and 20 day-sample, respectively (p<0.05). Number of total LAB of sample stored at $28^{\circ}C$ decreased more rapidly in comparison with that of sample stored at $0^{\circ}C\;or\;5^{\circ}C$. (2) Overall acceptability, taste, moistness and chewiness of freeze dried/reconstituted kimchi slightly decreased by freeze drying. However, acceptability of freeze dried/reconstituted kimchi was relatively good. (3) Overall acceptability of freeze dried/10 days-stored/reconstituted sample was slightly lower than that of reference sample (not-freeze dried sample). Overall acceptability of sample stored at $28^{\circ}C$ for 50 days decreased substantially in comparison with sample stored at $28^{\circ}C$ for 10 day. (4) In case of freeze dried/stored samples, sensory properties of sample stored at $5^{\circ}C$ for 60 days were not different from those of reference(sample stored at $0^{\circ}C$). Overall acceptability, taste, texture and crispness of sample stored at $28^{\circ}C$ started to decrease after 10 days. Odor and color of sample stored at $28^{\circ}C$ were changed after 50 days and 60 days, respectively.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.45-54
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• 2012

We investigated environmental characteristics of the tidal flat oyster aquafarms to clarifyeffects of the tidal flat environmental factors on growth and mortality of the tidal flat oyster Crassostrea gigas by the Net Bag Rack Culture System in two districts in Western Korea. In this study, we have carried out the basic environmental investigation on growth of the single tidal flat, water quality and sediments, etc. in Taean and Seosan districts, Choongcheongnam-do, where the single tidal flat oyster aquaculture have been performed by the net bag rack culture system. In June 2011 when the final survey carried out at the two districts in western Korea, the mortality in Seosan district was higher than that in Tae-an district. Judging from the results of growth and mortality of the single tidal flat oysters investigated at two sites of Jinsan-ri in Taean and Chang-ri in Seosan districts, two results of Taean district showed higher growth and lower mortality than those of Seosan district. It is assumed that the proper acceptable density possible for growth of the tidal flat seeds and the secure of economics, in case of plastic cultivate net with the size of $50{\times}80cm$, are about 200 individuals. In this study, It was clarified that selection of the suitable sites, the input into the net bag of high quality oyster seeds and selective dispersion in the optimal density of the single tidal flat oyster have an effect on growth and mortality of the tidal flat oyster.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.200-209
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• 1996

It is assumed to be an efficient method for keeping a germinability of weed seeds as long as possible, if a secondary dormancy is not induced by transferring the seeds of which dormancy was broken in wetting condition into drying condition. To investigate its validity, two experiments were carried out on seeds of 9 weed species ; to find out the most effective storage condition in breaking the dormancy of each weed species and to know whether there is a decrease in the germinability by transferring into drying storage condition. The dormancy of Chenopodium album and Stellaria aquatica was released well under the drying condition, but that of Echinochloa crus-galli var. oryzicola by soaking in water. Other weed species were released from dormancy by storage in wetting condition. When the seeds stored in the wetting or soaking condition, are air-dried and then restored at room or low temperature, a decreasing tendency of germinability which might cause a trouble in using them practically, was not observed except on the seeds of Persicaria vulgaris. In the case of Persicaria vulgaris, the low germination since 3 month-storage seemed not to be caused by drying, because a decrease of its germinability was observed with increasing storage period in all of the storage conditions. In contrast, high germination was induced as the seeds of Echinochloa crusgalli var. oryzicola, which were not germinated during the storage in low temperature and wetting condition, were transferred into the room temperature and drying condition. These results suggest that this approach can be one of the efficient methods for keeping a good germinability as long as possible in most weed seeds.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.1-7
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• 2006

To designate rural landscape spatially, land use and topographic features for 383 of "Ri"s or "Dong", which is a basic administrative unit in Korea, were analyzed using GIS application. We have categorized rural landscape into three types such as agricultural, natural and urban landscape by land use. On the basis of spatial landscape pattern, rural area could be classified into 6 groups of Mountainous area (MA), Mountainous village area (MV), Developing mountainous village area (DM), Plain agricultural area (PA), Developing plain village area (DP) and Urbanized area (UA) according to the ratios of land for agricultural and urban use as the criteria. In MA, the ratio of upland area including orchard was slightly larger than that of paddy, while that of paddy was about 1.5 times larger than upland in other groups. Forested area was distributed more than two-thirds among natural landscape area in MA, MV and DM. In plain types (PA and DP), the ratio of irrigated paddy was extremely larger than partially irrigated paddy and the ratio of water body area among the natural landscape area was two times as large as that of forested area. The ratio of land for industrial and livestock facilities among urban landscape area were 20% or more in MV, DM and DP, and it means that these facilities are mainly distributed in the developing ru ral area where residents and industry are closely related each other. According to the relative ratio of sloped land of 6 categorized areas, the MA area have lots of land with E and F slopes and MV and DM have all grades of sloped land evenly distributed in relative to other types of rural landscape. It has been showed that PA, DP and UA occupied more than two-thirds of land with A or B slope. In case of the analysis of topological distribution in 6 types of rural landscape, there were overwhelmingly lager highland areas in MA. Conclusively, we have confirmed that 6 types of rural landscape classified by land use pattern in 3 categorized areas such as agricultural, natural and urban landscape area would be useful for the management of rural area. For development of sustainable agriculture and the preservation of rural amenity, proper management ways should be properly applied according to rural landscape patterns.

• Journal of Conservation Science
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• v.36 no.6
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• pp.549-561
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• 2020

This study aimed to assess the performance and life of nine natural mineral dancheong pigments: Seokganju, Jinsa, Hwangto, Jahwang, Wunghwang, Seokrok, Noerok, Seokcheong, and Baekto. The design of the accelerated weathering test considered the domestic climate characteristics and the location of Dancheong. Outdoor weathering tests were conducted at the Research Institute in Daejeon and the Sungnyemun Gate in Seoul to confirm the field reproducibility of the accelerated weathering test. Monitoring of the physical changes in pigments through accelerated and outdoor weathering tests are based on ultraviolet exposure dose. Despite small cracks at the beginning of the tests, the monitoring showed that Seokganju and Baekto had no marked physical changes, but the surface cracks of Jinsa and Seorok continue to expand. Hwangto and Noerok were marked with water or were resin stained, and the particles of Jahwang, Wunghwang, and Seokcheong had lost their luster. Despite the absolute difference in color change in each test, the final chromaticity change patterns of pigments were similar in that the color difference between Baekto and Noerok was below five, and Jina was above 28. The physical and surface color pigment changes were more concentrated in outdoor weathering tests than in accelerated tests, and the Seoul site was more intense than the Daejeon site. This is because outdoor weathering tests are exposed to severe variations of temperature and moisture or deposition of dust particles and, in the case of Seoul, the site is more exposed to the external environment than the Daejeon site.

• Journal of Food Hygiene and Safety
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• v.36 no.3
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• pp.248-256
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• 2021

A total of 120 samples corresponding to 12 categories of dried processed fishery products distributed in Gyeonggi-do were examined for radioactivity contamination (¹³¹I, ¹³⁴Cs, ¹³⁷Cs) and heavy metals (lead, cadmium, arsenic, and mercury). One natural radioactive material, ⁴⁰K, was detected in all products, while the artificial radioactive materials ¹³¹I, ¹³⁴Cs and ¹³⁷Cs were not detected at above MDA (minimum detectable activity) values. The detection ranges of heavy metals converted by biological basis were found as follows: Pb (N.D.-0.332 mg/kg), Cd (N.D.-2.941 mg/kg), As (0.371-15.007 mg/kg), Hg (0.0005-0.0621 mg/kg). Heavy metals were detected within standard levels when there was an acceptable standard, but the arsenic content was high in most products, although none of the products had a permitted level of arsenic. In the case of dried processed fishery products, there are products that are consumed by restoring moisture to its original state, but there are also many products that are consumed directly in the dry state, so it will be necessary to set permitted levels for heavy metals considering this situation in the future. In addition, Japan has decided to release contaminated water from the Fukushima nuclear power plant into the ocean, so there is high public concern about radioactivity contamination of food, including fishery products. Therefore, continuous monitoring of various food items will be necessary to ease consumers' anxiety.