• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.231-236
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• 2010

The growth in global energy demand and the increased recognition of the impacts of carbon dioxide emissions from fossil fuel plants have aroused a renewed interest on nuclear energy. Many countries are looking afresh at building more nuclear power stations to deal with the twin problems of global warming and the need for more generating capacity. Many in the nuclear community are also anticipating a significant growth of new nuclear generation in the coming decades. If there is a nuclear renaissance, will the expansion of nuclear power be compatible with global non-proliferation and security? or will it add to the environmental burden from the large inventory of spent nuclear fuel already produced in existing nuclear power reactors? We learn from past peaceful nuclear activities that significant concerns associated with nuclear proliferation and spent-fuel management have resulted in a decrease in public acceptance for nuclear power in many countries. The terrorist attack in the United States (US) on September 11, 2001 also raised concern for security and worry that nuclear materials may fall into the wrong hands. As we increase the use of nuclear power, we must simultaneously reduce the proliferation, security and environmental risks in managing spent-fuel below where they are today.

• Preventive Nutrition and Food Science
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• v.10 no.2
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• pp.179-186
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• 2005

This study was conducted to find the gender and age differences in dietary behaviors and food consumption pattern of Korean American adults living in western parts of USA. The structured survey forms and self-administered food frequency questionnaire were used to assess dietary behavior and nutrient intakes. It was found that younger subjects kept their meal time more irregularly and skipped breakfast more often than older subjects due to lack of time. There were significant age differences in skipping meals, kind of skipping meals, and the reasons for skipping meals. Young subjects consumed more American type food while older subjects consumed more traditional Korean food. Nutrient intakes of males' except for the elderly were significantly higher in energy, protein, Fe and P than those of females'. Vitamin A and vitamin C intake were significantly higher in females. Energy ratio of carbohydrate: protein: fat was 56.2 : 16.8 : 27.0. Females consumed more plant food as their dietary sources of protein, fat, Ca and Fe, compared to males. Ca intakes of participants' were below $75\%$ of RDA except for the youngest male and $30\~49$ aged male and females. Futhermore, Ca intake was below $70\%$ after age 50 in both genders. Effective nutrition education program targeting Korean Americans in the community should be developed and implemented to increase Ca consumption.

• Radioisotope journal
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• v.21 no.3
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• pp.46-60
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• 2006

In recent years the progress of nuclear medicine advanced dramatically in imaging and targeted radionuclide therapy is able to open op exciting perspectives as standard diagnostic and therapeutic modalities, complementing conventional modalities. Positron emission tomography/computed tomography (PET/CT) technology with FDG has been developed clinically in less than 10 years as a routine standard in oncological imaging, including a number of other fluorinated radiopharmaceuticals being evaluated for their ability to complement FDG. However, the limitation of FDG-PET such as non-specific uptake and its short half-life is not compatible with the time necessary for optimal tumour targeting. Therefore, a development of innovative positron-emitting radionuclides with half-lives longer than 10 h is needed. For therapeutic applications, the injection of higher activities is required to reach efficient adsorbed doses in radioresistant solid tumours, while limiting the irradiation of vital organs. In this application, the longer half-life of radiolsotopes are more fit well for radionuclide therapy. To achieve this, researches have to be carried in a largor spectrum of radionuclides for diagnosis and therapy. In the context of rapidly growing nuclear medicine and strong demanding innovative radionuclides, a high-energy (100 MeV), high-intensity (-mA) accelerator with proton (PEFF at KAFRI). will be operating in 2011. The priorities of PEFP will include supporting the nuclear medicine research community by providing those radionuclides with current limited availability by means of a high-energy, high-intensity accelerator.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1297-1306
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• 2019

Probabilistic safety assessments (PSA) have been used for several decades to visualize the risk level of commercial nuclear power plants (NPPs). Since the role of a human reliability analysis (HRA) is to provide human error probabilities for safety critical tasks to support PSA, PSA quality is strongly affected by HRA quality. Therefore, it is important to understand the underlying limitations or problems of HRA techniques. For this reason, this study conducted a survey among 14 subject matter experts who represent the HRA community of domestic Korean NPPs. As a result, five significant HRA issues were identified: (1) providing a technical basis for the K-HRA (Korean HRA) method, and developing dedicated HRA methods applicable to (2) diverse external events to support Level 1 PSA, (3) digital environments, (4) mobile equipment, and (5) severe accident management guideline tasks to support Level 2 PSA. In addition, an HRA method to support multi-unit PSA was emphasized because it plays an important role in the evaluation of site risk, which is one of the hottest current issues. It is believed that creating such a catalog of prioritized issues will be a good indication of research direction to improve HRA and therefore PSA quality.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.15-25
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• 2020

Biogas production potential was experimentally estimated for mono- and co-digestion of cow manure and waste grass. The two organic wastes were mixed at five different ratios (100:0, 75:25, 50:50, 25:75, 0:100) on the volatile solids basis, and were assessed using biochemical methane potential (BMP) test. Thee reaction temperatures, 25℃, 30℃ and 35℃, were applied as well, resulting in 15 different combinations for the test. The results showed that both higher temperature and waste grass mixing ratio resulted in higher methane yield and maximum methane production rate. Based on the experimental results, a theoretical farm- or community-scale (240 or 2400 ㎥) anaerobic digester was designed to evaluate the energy balance associated with mono- and co-digestion of the wastes at different temperatures. Although the energy production increased as the temperature and the waste grass mixing ratio increased, the net energy gain, energy production subtracted by energy consumption for heating and maintenance, was estimated to be the highest at 30℃, followed by at 35℃ and 25℃. Therefore, it is advised that both the experimental methane production and the detailed design parameters must be considered for the optimization of the net energy gain from these wastes.

• Journal of Science and Technology Studies
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• v.6 no.1 s.11
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• pp.119-152
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• 2006

This paper deals with the historical development of research community in Korea. As the former studies of the korean scientific community show, the government supported institutes played an important role in the formation of research community. Therefore the theme of this study is concerned with the historical development of the government supported institutes and the features of their researcher group. In this paper following questions will be answered: How the social status of these researcher group is changed, what kind of response on social problems or national politics they had, and which characteristic they showed with regards to the identity problem. After the korean liberation the government institutes, such as the Chungang Kongop Yonguso(industrial research center)and the Korean Atomic Energy Research Institute, contributed to the development of the first generation of research group. However this research group could hardly identify themselves as researcher, because they spent much time on testing, evaluation or education. The identity problem is also resulted from the deficiency of authority as research institute. The status of researcher had no difference from that of civil servant. With the establishment of KIST the korean research community came into blossom. The government supported institutes, which were founded after the model of KIST, allowed quantitative and qualitative growth of research community. Thanks to the guarantee of institutional authority and the new reward system, the researcher could get respect and improve its social status. During this period the researcher volunteered to help the government policies. We can find often the nationalistic statements in the research community. During 1990s the research group demonstrated different behaviors and attitude toward the government. The nationalistic ideology disappeared. Instead of that, the research group criticized the government policies and took actions against the government. Those changes are related with the lowered position of government supported institutes.

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.8-22
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• 1998

The phytomass and productivity of the evergreen needle pines(Pinus densiflora and Pinus rigida) and of the deciduous broad- leaved oaks(Quercus acutissima, Quercus variabililis and Quercus mongolica) in the watershed forests of South Han River, central part of Korea was estimated by the allometry. The allometic relations between D$^2$H and dry weight of stem(Ws), branches(Wb) and leaves(Wl) of these forests were as follows: Pinus densiflora community : logWs=0.58482D$^2$H-0.42417 logWb=0.6234D$^2$H-1.2321 logWl=0.2247D$^2$H-0.09359 Pinus rigida community : logWs=0.9218D$^2$H-1.4692 logWb=1.0064D$^2$H-2.2278 logWl=0.6275D$^2$H-1.1715 Quercus acutissima community : logWs=0.96659D$^2$H-1.56975 logWb=0.86315D$^2$H-2.17944 logWl=0.79876D$^2$H-1.97137 Quercus variabilis community : logWs=0.4753D$^2$H＋0.20026 logWb=0.5725D$^2$H-0.92006 logW1=0.61649D$^2$H-1.4288 Quercus momgolica community : logWs=0.5526D$^2$H-0.1228 logWb=0.5188D$^2$H-0.9787 logWl=0.7754D$^2$H-2.6273 From the above formulae, the phytomass of Pinus densiflora was estimated to be much as 1,200,000 ton, Pinus rigida 610,000 ton, Quercus acutissima 289 ton, Quercus variabilis 2,800ton and Quercus mongolica 570,000 ton in the surveyed area, respectively. Accordingly, the phytomass of Pinus densiflora forest was occupied about 43.9 % in toto and was higher thanthose of other forests. The phytomass of watershed forests belonging to Degree 8 and Degree7 divided by degree of green naturality(DGN) was 74,000 ton and 2,000,000 ton, resfectively. Accordingly, the watershed forests in South Han River were mainly composed of Pinus densiflora and Quercus mongolica forests belonging to Degree 7.

• Korean Journal of Community Nutrition
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• v.9 no.2
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• pp.173-182
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• 2004

We carried out a validation-calibration study of the food frequency questionnaire (FFQ) that we had previously developed for a community-based cohort of the Korean Genome and Health Study of the Korea National Genome Research Institute. We have collected a total of 254 3-day diet records (DRs) from 400 subjects, 200 each randomly selected from the two study cohorts of Ansung and Ansan. FFQ was administered at the time of cohort recruitment in 2001, and DRs were collected during a two month period from January through February of 2002. The mean age was 52.2 years. Farming for men and housewife for women were the most common occupations. The majority of the subjects had undergone 6∼12 years of education. The general characteristics including demographic and other data were not different from the total cohort subjects. Absolute levels of consumed nutrients including total energy (energy), protein, fat, carbohydrate, calcium, phosphorus, sodium, potassium, iron, retinol, carotene, vitamin A, thiamin, riboflavin, niacin and vitamin C were compared. The average of energy intake was not significantly different between the data collected by the 2 methods. However, consumptions of protein and fat were higher in data of DRs, whereas that of carbohydrate was higher in FFQ data. Significant correlation of each nutrient consumption between the data sets was observed (p ＜ 0.05) except in the case of iron, while the average correlation coefficient between them was 0.22 ranging from 0.33 for energy to 0.11 for iron. The results of cross classification by quantile for exact classification ranged from 25.2% (carotene) to 35.0% (phosphorus), and from 64.6% (vitamin A) to 76.4% (retinol) for adjacent classification. The proportion of completely opposite classification was 8.1% in average. Calibration slope was estimated by regression and calibration parameters ranged from 0.025 for carotene to 0.423 for niacin. We conclude that the FFQ we have developed is an appropriate tool for assessing the nutrient intakes as ranking exposures in epidemiology studies in view that amounts of consumed nutrients obtained by FFQ were similar to those collected by DRs, that correlations between consumed nutrients collected by these methods were significant, and that classification results were relatively fair. The correlation coefficients, however, were lower than expected, which may be mainly due to the survey season. In fact, any short-term dietary survey cannot accurately reflect the overall dietary intakes that change heavily depending on seasons. Further studies including the analysis of chemical indices would be helpful for the studies of causal relationship between the diet and disease.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.504-520
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• 2020

Proliferation of shrubs at the expense of native forage in pastures has been associated with large changes in dry-matter intake and dietary components for grazing ruminants. These changes can also affect the animals' physiology and metabolism. However, little information is available concerning the effect of pastoral-shrub grazing on the rumen bacterial community. To explore rumen bacteria composition in grazing yaks and the response of rumen bacteria to increasing shrub coverage in alpine meadows, 48 yak steers were randomly assigned to four pastures with shrub coverage of 0%, 5.4%, 11.3%, and 20.1% (referred as control, low, middle, and high, respectively), and ruminal fluid was collected from four yaks from each pasture group after 85 days. Rumen fermentation products were measured and microbiota composition determined using Ion S5™ XL sequencing of the 16S rRNA gene. Principal coordinates analysis (PCoA) and similarity analysis indicated that the degree of shrub coverage correlated with altered rumen bacterial composition of yaks grazing in alpine shrub meadows. At the phyla level, the relative abundance of Firmicutes in rumen increased with increasing shrub coverage, whereas the proportions of Bacteroidetes, Cyanobacteria and Verrucomicrobia decreased. Yaks grazing in the high shrub-coverage pasture had decreased species of the genus Prevotellaceae UCG-001, Lachnospiraceae XPB1014 group, Lachnospiraceae AC2044 group, Lachnospiraceae FCS020 group and Fretibacterium, but increased species of Christensenellaceae R-7 group, Ruminococcaceae NK4A214 group, Ruminococcus 1, Ruminococcaceae UCG-002, Ruminococcaceae UCG-005 and Lachnospiraceae UCG-008. These variations can enhance the animals' utilization efficiencies of cellulose and hemicellulose from native forage. Meanwhile, yaks grazed in the high shrub-coverage pasture had increased concentrations of ammonia nitrogen (NH₃-N) and branched-chain volatile fatty acids (isobutyrate and isovalerate) in rumen compared with yaks grazing in the pasture without shrubs. These results indicate that yaks grazing in a high shrub-coverage pasture may have improved dietary energy utilization and enhanced resistance to cold stress during the winter. Our findings provide evidence for the influence of shrub coverage on the rumen bacterial community of yaks grazing in alpine meadows as well as insights into the sustainable production of grazing yaks on lands with increasing shrub coverage on the Qinghai-Tibet Plateau.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1656-1664
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• 2009

Bioaugmentation of bioreactors focuses on the removal of numerous organics, with little attention typically paid to the maintenance of high and stable nitrite accumulation in partial nitrification. In this study, a bioaugmented membrane bioreactor (MBR) inoculated with enriched ammonia-oxidizing bacteria (AOB) was developed, and the effects of dissolved oxygen (DO) and temperature on the stability of partial nitrification and microbial community structure, in particular on the nitrifying community, were evaluated. The results showed that DO and temperature played the most important roles in the stability of partial nitrification in the bioaugmented MBR. The optimal operation conditions were found at 2-3 mgDO/l and $30^{\circ}C$, achieving 95% ammonia oxidization efficiency and nitrite ratio ($NO_2^-/{NO_x}^-$) of 0.95. High DO (5-6 mg/l) and low temperature ($20^{\circ}C$) had negative impacts on nitrite accumulation, leading to nitrite ratio drop to 0.6. However, the nitrite ratio achieved in the bioaugmented MBR was higher than that in most previous literatures. Denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH) were used to provide an insight into the microbial community. It showed that Nitrosomonas-like species as the only detected AOB remained predominant in the bioaugmented MBR all the time, and coexisted with numerous heterotrophic bacteria. The heterotrophic bacteria responsible for mineralizing soluble microbial products (SMP) produced by nitrifiers belonged to the Cytophaga-Flavobacterium-Bacteroides (CFB) group, and $\alpha$-, $\beta$-, and $\gamma$- Proteobacteria. The fraction of AOB ranging from 77% to 54% was much higher than that of nitrite-oxidizing bacteria (0.4-0.9%), which might be the primary cause for the high and stable nitrite accumulation in the bioaugmented MBR.