• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.172-178
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• 2001

K-Ar dating system of Korea Basic Science Institute (KBSI) was installed in 1997 and has been used since then. The system consists of high temperature graphite furnace, gas purification system, and mass spectrometer with data acquisition system. K-Ar age is determined by the measurement of the concentrations of Ar and K through isotope dilution method using $^{38}Ar$ as spike and flame spectroscopy, respectively. The accuracy and reliability for the K-Ar age are checked using the several K-Ar standard materials. Although the exact age determination for young samples of less than 1 Ma is hampered by small fluctuations of sensitivity and mass discrimination, the present system yields the reliable K-Ar age compared to the standard materials of Tertiary and Mesozoic age. The measurements for the SORI93 biotite with the recommended K-Ar age of $92.6\pm$0.6 Ma and Bern4M muscovite of $18.5\pm$0.6 Ma yield the reliable age of $92.1\pm$1.1 Ma and $17.8\pm$0.2 Ma, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.167-167
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• 2013

최근에 산화물 형광체는 황화물 형광체에 비해 높은 화학적 안정성을 나타내기 때문에 백색 발광 다이오드, 전계방출 디스플레이와 플라즈마 디스플레이 패널에 그 응용성을 넓히고 있다. 마그네슘 니오베이트(magnesium niobate, MgNb2O6)는 우수한 유전 특성(상대 유전상수=18.4)을 나타내기 때문에 마이크로파 유전체로 응용 가능하며, 단일상 릴랙서 페라브스카이트(relaxor perovskite) Pb(Mg1/3Nb2/3)O3을 합성하기 위한 전구체 (precursor)로 널리 사용되고 있으며, 나이오븀산염 이온에서 다양한 색상을 방출하는 활성제 이온으로 효율적인 에너지 전달이 일어남으로써 Sm3+, Dy3+, Eu3+와 같은 희토류 이온의 좋은 모체 격자로 개발할 수 있다. 본 연구에서는 마그네슘 니오베이트 MgNb2O6 모체 결정에 다양한 활성제 이온, 즉 Eu3+, Sm3+, Dy3+, Tb3+를 선택적으로 주입하여 발광 효율이 높은 천연색 형광체를 합성하고자 한다. 특히, 모체 결정에 주입되는 활성제 이온 주위의 국소적인 환경이 반전 대칭에서 변형되는 척도를 조사하여 활성제의 주 발광 파장의 세기가 최대가 되는 최적의 조건을 결정하고자 한다. Mg1-1.5xNb2O6:REx3+ 형광체 분말 시료는 초기 물질 MgO, Nb2O5와 희토류 이온을 화학 반응식에 맞게 정밀 저울로 측량하여 플라스틱 용기에 ZrO2 볼과 함께 넣고, 소정의 에탄올을 채운 뒤 밀봉하고서, 300 rpm의 속도로 20시간 볼밀 (ball-mill) 작업을 수행하였다. 그 후, 체(sieve)로 ZrO2 볼을 걸러낸 다음에 혼합된 용액을 각 비커에 담아서 $40^{\circ}C$의 건조기에서 24시간 건조하였고, 건조된 시료를 막자 사발에 넣고 잘게 갈고 80 ${\mu}m$의 체로 걸러낸 후에, 알루미나 도가니에 활성제 이온별로 각각 담아, 전기로에 장입하여 매분당 $5^{\circ}C$의 비율로 온도를 상승시켜 $350^{\circ}C$에서 5시간 동안 하소 공정을 실시한 후에, 온도를 계속 일정한 율로 증가시켜 $1,200^{\circ}C$에서 5시간 동안 소성하여 합성하였다. 합성된 형광체 분말의 결정 구조는 $Cu-K{\alpha}$ 복사선(파장: 1.5406)을 사용하여 X-선회절장치로 측정하였으며, 형광체의 표면 형상은 전계형 주사전자현미경으로 관측하였다. 흡광와 발광스펙트럼은 제논 램프를 광원으로 갖는 형광 광도계를 사용하여 측정하였다. 모체 결정에 활성제 이온 Eu3+, Sm3+, Dy3+, Tb3+가 도핑된 형광체 분말은 각각 적색, 주황색, 황색, 녹색 발광이 관측되었다. 각 발광 스펙트럼과 결정 입자의 크기와 형상 사이의 상호 관계를 조사하였다. 실험 결과로부터, 각 형광체의 발광 파장은 활성제 이온의 종류 와 서로 밀접하게 관련되어 있으며, 형광체 시료 합성시 활성제 이온의 농도를 선택적으로 조절함으로써 발광의 세기를 제어할 수 있음을 확인하였다.

• Korean Journal of Community Nutrition
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• v.27 no.5
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• pp.406-421
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• 2022

Objectives: The purpose of this study was to investigate the blood biochemical characteristics, comorbidities, dietary intake, and other risk factors leading to poor glycated hemoglobin (HbA1c) control in elderly Korean diabetes patients over 65 years of age. Methods: Data from the 4^th (2007-2009) and the 7^th (2016-2018) Korea National Health and Nutrition Examination Surveys (KNHANES) were used. Socio-demographic characteristics (age, gender, region, household income, education level, marital status, nutrition education, diabetes duration and diabetes treatment), lifestyle characteristics (drinking, smoking, regular walking, and subjective health perception), anthropometric characteristics (height, weight, and waist circumference), blood biochemical characteristics (HbA1c, high- density lipoprotein cholesterol, triglycerides, total cholesterol, blood urea nitrogen, and blood creatinine), co-morbidities (obesity, hypertension, hypercholesterolemia, hypertriglyceridemia, and anemia), energy and nutrients intake, food group intake, and HbA1c control-related risk factors were compared. Results: Compared to the 4^th survey, the 7^th survey showed an increase in diabetes prevalence among men, an increase in the prevalence of diabetes in the older patients, and an increase in the duration of diabetes. The energy ratio from carbohydrate consumption in the 7^th survey was lower than in the 4^th. Compared to the 4^th survey, thiamine and riboflavin intake had improved, and the intakes of vitamin A, vitamin C, and niacin had worsened in the 7^th. A comparison of food group intakes showed that there was a decrease in the consumption of whole grains, potatoes, and milk and an increase in the intake of beverages and alcoholic beverages. The risk factors for poor control of HbA1c were the duration of diabetes and co-morbid hypertriglyceridemia in the 4^th survey, whereas subjective health perception, obesity, and hypercholesterolemia as co-morbidities were found to be risk factors in the 7^th in addition to the risk factors highlighted in the 4^th survey. Conclusions: For the future management of elderly Korean diabetes patients, greater care is indicated for men over 75 years, and those with low levels of education. It is necessary to increase the intake of milk and vegetables, and reduce the intake of beverages and alcoholic beverages. In addition, it is necessary to reduce the incidence of obesity, hypercholesterolemia, and hypertriglyceridemia for proper control of blood sugar.

• Journal of Life Science
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• v.12 no.5
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• pp.544-548
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• 2002

The object of this study was to investigate nitrogen fixation activity of rhizobium inoculated at seed coat when drought condition was applied in flowering period of soybean c.v. Samnamkong. The rhizobia used in this experiment were indigenous rhizobium, R2l4, RJl-29, USDA110 and USDA122. The experiment was done with 1/2000 Wagner pots in laboratory and greenhouse and was tested in completely randomized design with four replications. Nitrogen fixation activity in coventional culture was the highest in R2l4 and indigenous rhizobium among the five rhizobia strains. As given drought condition from flowering to maturity, nitrogen fixation activity was higher in R2l4 and RJl-29 than indigenous rhizobium. Leaf area and relative index (drought/convention) of pod weight were higher in USDA122, RJl-29 and R2l4 than indigenous rhizobium as given drought condition from flowering to maturity. High positive correlation was observed between nitrogen fixation activity of rhizobium and relative index(drought/convention) of pod weight. High negative correlation was observed between respiration of plant and relative index (drought/convention) of leaf area.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.26-30
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• 2000

Degradabilities of the dicamba by microorganisms isolated from soil and by enzymes in the turfgrass, Zoysia Japonica S. were investigated. Five species of dicamba-deading microorganisms including Acidovorax sp., Alcaligenes sp., and Variovorax sp. were isolated from soils by enrichment culture. All strains in nutrient-free inorganic medium treated with 10 ppm of dicamba degraded average 90% of the dicamba 21 days after incubation. 5-Hydroxydicamba, major metabolite, was detected from the culture broth. The half life of dicamba in the phosphate buffer extracts of Zoysia Japonica S. was 2.5 to 2.7 days. Trace amounts of 4- and 5-hydroxydicamba were detected in the extracts.

• Journal of the Korean Ceramic Society
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• v.41 no.4
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• pp.297-301
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• 2004

Nano-sized mullite (3Al$_2$O$_3$$.$2SiO$_2$) colloids were prepared by use of the spray combustion method. For combustion reaction, Al(NO$_3$)$_3$$.$9$H_2O$, and CH$_{6}$N$_4$O were used as an oxidizer and a fuel respectively, and then colloidal silica was also added as 2SiO$_2$source for mullite. The temperature of the reaction chamber was kept at 80$0^{\circ}C$ to initiate the ignition of droplets of the mixed precursors. For preventing droplet coagulation, the droplet number concentration was reduced using the metal screen filter, and the residence time of aerosol was kept at 2.5 seconds for laminar flow. The synthesized colloidal particles had an uniform spherical shape with 130 nanometer size and the crystalline phase showed the mullite with stoichiometry in the observations of XRD and TEM.

• Korean Journal of Community Nutrition
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• v.22 no.4
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• pp.347-355
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• 2017

Objectives: Although dietary supplements use in Korea has been rapidly increasing and women are more likely to take dietary supplements more than men, only a few studies have been conducted to investigate factors contributing to gender differences in dietary supplement use in the Korean population. The aim of this study is to evaluate the prevalence of dietary supplement use and also identify gender-specific key factors that contribute to it using the data of the 4th KNHANES. Methods: Subjects were divided into user and non-user groups according to the answer given to the question that asked whether they had used any dietary supplement for more than 2 weeks on a regular basis during the previous year. Factors related to dietary supplement use were examined by general characteristics, health behavior and eating behavior. Results: Prevalence of dietary supplement use was 13.6% for men and 20.6% for women. Users were more likely to be middle-aged, have higher income and education, have a spouse, or reside in dong areas in both men and women. Regarding health behaviors, men with desirable lifestyle behavior were more likely to take dietary supplements, while men who smoked were less likely to take dietary supplements. Regarding disease history, both men and women with a current disease had higher odds of taking supplements. With regard to dietary behavior, frequent eating out and nutrition attitude were associated with higher odds of taking supplements in both men and in women. Conclusions: Health or dietary behavior related factors that were associated with taking supplements differed by gender. These findings can be useful for planning gender-specific dietary education and health programs.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.271-277
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• 1985

A polarograph with specially designed cell compartment usable in kinetic study of the mitochondrial respiration of a small sized sample was made, and its performance and experimental conditions were examined. An applied potential (ca-1.2V vs. SCE) which gives rise to the second step reduction of oxygen caused a considerable level of a residual current independent of oxygen, which is temporarily interpreted as the reduction current of the membrane-bound redox material(s) of mitochondria. A potential corresponding to the first slop reduction of oxygen (ca-0.4V vs SCE) did not produce the residual current. Thus, it is suggested that a measurement of oxygen concentration in a sample of mitochondria and submitochondrial particles by using dropping mercury electrode should be done with an applied potential of about -0.4V vs SCE. Consumption of oxygen by mitochondria was observed to follow practically zero order kinetics. Its rate constant exhibited the proportional relationship with the respiratory activity of mitochondria. Usefulness of tile instrument was properly demonstrated in the work on the temperature effect on the respiration of mitochondria isolated from several plant 4issues which were selected on the basis of chilling susceptivity.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.449-460
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• 2022

The morphology and whole genome sequence of Spodoptera exigua nucleopolyhedrovirus K1 (SeNPV-K1) isolated in Korea were analyzed for the use as an eco-friendly control source against S. exigua. The polyhedra of SeNPV-K1 was amorphous with a size of 0.6-1.8 ㎛, and there was no external difference with the previously reported SeNPV. As a result of analyzing the nucleotide sequence of the whole genome, it was composed of 135,756 bp, which is 145 bp more than that of the previously reported SeNPV. The G+CG+C content was 44% and there were 6 homologous repeated sequences, so there was no significant difference from the previous report. As a result of ORF analysis, SeNPV-K1 had 137, two fewer than those previously reported, and 4 ORFs present only in SeNPV-K1 were confirmed. These 4 ORFs are non-essential genes and were not considered to have a significant influence on the characteristics of the SeNPV. The genome vista analysis showed that the overall sequence similarity between SeNPV-K1 and the previously reported SeNPV was very high. The whole genome of SeNPV-K1 analyzed for the first time in Korea was found to be similar to the previously reported SeNPV, but it was confirmed that it was a novel resource in Korea with different isolate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4081-4086
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• 2014

Cellulose acetate butyrate (CAB) is a biodegradable resin with excellent optical properties, but it is difficult to apply film process. In this study, an attempt was made to improve the processability of CAB using polyactic acid and the mechanical properties using an impact modifier. Polylacitc acid (PLA)/Cellulose acetate butyrate (CAB) blends with an impact modifier were prepared using a twin screw extruder. The temperature range was $140^{\circ}C$ to $200^{\circ}C$, and the screw speed was fixed to 200 rpm. To evaluate the miscibility of impact modified CAB/PLA, the glass transition behavior and morphology were observed by DSC and FE-SEM. The mechanical properties were investigated by dynamic mechanical analysis (DMA) and a Universal Testing Machine (UTM). In addition, the effect of an impact modifier in the polymer matrix was determined using a notched Izod impact strength tester. Finally, the PLA/CAB/impact modifier 75/25/10 ratio was found to be a compatible system. In the 10wt.% impact modifier, the sample had a 4 times higher izod impact strength than the non-toughening composition.