• 대한지역사회영양학회지
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• 제19권3호
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• pp.231-240
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• 2014

Objectives: This study was intended to examine the seasonal differences in outdoor activity times and dietary vitamin D intakes, and explicates their relative impact on improving serum 25-(OH) vitamin D status among Korean young women. Methods: A cross-sectional study was conducted with 135 free-living women aged 19-39 years in Daegu-Kyungbook, Korea. We compared the results from 52 women for the summer and 83 women for the winter. Dietary intake of vitamin D was assessed by 24 hour recall method for non-consecutive three days as well as by food frequency method. Daily outdoor activity times were derived from 24 hour physical activity diary. Results: The average dietary intake of vitamin D of the participants by 24 hour recall method was 3.1 ${\mu}g$ during the summer, 3.3 ${\mu}g$ during the winter, showing no significant difference between the two seasons. Times spent on outdoor activities (p < 0.01) in the summer (= $23.8{\pm}23.6$ min) were much longer than that in the winter (= $10.8{\pm}13.4$ min). The serum 25-(OH) vitamin D levels of participants were $17.5{\pm}7.5$ ng/mL in the summer and $13.4{\pm}4.3$ ng/mL in the winter, showing that the latter was significantly lower than that of the former (p<0.001). The serum 25-(OH) vitamin D levels of subjects were positively related to outdoor activities (r=0.315, p<0.05) during the summer, while related to dietary intake (r=0.252, p<0.05) during the winter. Conclusions: In order to improve the current vitamin D status of Korean young women, nutrition education programs should focus on increasing more dietary intake especially during the winter, and performing more outdoor activities in other seasons.

• 한국산림과학회지
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• 제96권4호
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• pp.408-413
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• 2007

굴피나무 수피를 채취하여 건조시킨 후 분말로 제조하여 95% EtOH로 추출하고 여기서 얻어진 EtOH 조추출물의 하나는 헥산(n-hexane), 디클로로메탄($CH_2Cl_2$)으로, 또 하나는 석유에테르(petroleumether), 디에틸에테르($Et_2O$) 및 에틸아세테이트(EtOAc)를 사용하여 순차적으로 분획하였다. 이중 디클로로메탄($CH_2Cl_2$) 가용부(6.0 g)는 EtOH-$CHCl_3$ (7:3, v/v)를 용출용매로 한 Sephadex LH-20 칼럼($72.0{\times}5.0cm$)을 사용한 칼럼크로마토그래피를 실시하였다. 또한 디에틸에테르($Et_2O$) 가용부는 $CHCl_3$-MeOH (9:3, v/v)을 용출용매로 한 silica gel 칼럼($42.0{\times}3.5cm$)을 사용하여 칼럼크로마토그래피를 실시하였다. 단리된 화합물들은 TLC로 확인한 후 $^1H$-, $^{13}C$-NMR, HMBC 등의 스펙트럼을 사용하여 화학구조를 규명하였고 EI-MS로써 분자량을 측정하였다. 추출물로부터 3, 3', 4', 5, 7-pentahydroxyflavone (quercetin), 3, 3', 4', 5, 5', 7-hexahydroxyflavone (myricetin), flavonoids 배당체인 kaempferol-3-O-${\alpha}$-L-rhamnopyranoside (afzelin), quercetin-3-O-${\alpha}$-L-rhamnopyranoside (quercitrin), myricetin-3-O-${\alpha}$-L-rhamnopyranoside (myricitrin)등을 단리할 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.56-60
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• 2003

전기분해에 의한 부상현상을 이용하여 유류로 오염된 토양 세정 후 발생되는 유출수 중 유분 등을 분리하기 위한 적정 운전조건을 찾고자 하였다. 전기분해 반응조(200${\times}$10${\times}$15cm)를 이용하여 혼합계면활성제($POE_5$ : $POE_{14} $, 1:1) 1%용액에 디젤을 1,000 mg/L 농도로 용해시켜 실험하였다. 양극에는 티타늄 코팅전극, 음극으로는 스테인레스 스틸전극을 이용하였다. 반응시간은 62분(반응 :60분, 부상시간 :2분)이었으며 전압은 6V였다. 전해질 첨가에 의한 영향을 알아보기 위하여 실험한 결과, 전해질을 첨가하였을 경우 첨가하지 않았을 때보다 40% 정도의 효율이 증가하였다. 적정 전해질, 주입농도 및 반응시간을 알아보기 위하여 1N NaCl과 NaOH의 농도를 변화시켜 가면서 실험하였다. NaCl의 경우 더 좋은 효율을 나타내었다. 전해질의 농도는 0.2-1.0%의 농도범위에서 NaCl와 NaOH 모두 농도에 따라 순차적으로 효율이 증가하였다. 두 전해질 모두 0.4-1.0% 농도 범위에서 평형에 도달하는 시간은 20분으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.109-110
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• 2008

We have performed a density functional theory study to investigate the reaction of the $HfCl_4$ molecule on $H_2O$ terminated Si (001)-$(2\times1)$ surface. The reaction of the $HfCl_4$ molecule is more favorable on OH-terminated site than H-terminated site. The first $HfCl_4$ molecule is adsorbed on a OH-terminated site with 0.21 eV energy benefit. The second $HfCl_4$ molecule is adsorbed on the most adjacent OH-terminated site of the first molecule and the energy benefit is 0.28 eV. The third and forth molecules have same tendency with the first and second ones. The adsorption energies of the fifth and sixth $HfCl_4$ molecules are 0.01 eV, -0.06 eV respectively. Therefore, we find that the saturation Hf coverage is approximately 5/8 of the available hydroxyl site, which is $2.08\times10^{14}/cm^2$. Our model is well matched with an experimental study by reference.

• 자원환경지질
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• 제39권2호
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• pp.181-190
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• 2006

고준위 방사성 폐기물에 포함된 핵종을 고정화시킬 수 있는 유망한 물질의 하나인 석류석의 화학적 안정성에 대한 연구결과가 미흡한 실정이다. 따라서 본 연구에서는 3가와 4가의 Pu의 모조제로써 Gd 및 Ce을 함유하고 있는 다양한 조성의 석류석을 합성하여 화학적 내구성의 척도인 용출실험을 실시하였다. 증류수로부터의 Gd과 Ce에 대한 모든 시료의 용출속도가 각각 $1.2{\times}10^{-4}{\sim}4.6{\times}10^{-6}g/m^2/day$, 및 $7.5{\times}10^{-5}{\sim}1.8{\times}10^{-7}g/m^2/day$를 보임으로써 기존의 연구된 고화체에 대한 분석 자료와 비교 시 화학적 내구성이 우수한 것으로 판단되었다. 특히 알칼리 또는 산성조건에서의 용출실험 자료가 전무한 실정인 바, 이를 보완하기 위하여 0.01M-NaOH 및 0.01M-HCl 용액을 사용한 용출실험을 수행하였다. 실험결과, 0.01M-HCl 용액을 이용한 용출실험 결과 얻어진 Gd과 Ce에 대한 모든 시료의 용출속도는 각각 $2.5{\times}10^{-1}{\sim}6.9{\times}10^{-3}g/m^2/day$ 및 $3.7{\times}10^{-1}{\sim}3.1{\times}10^{-3}g/m^2/day$였다. 또한 0.01M-NaOH 용액으로부터의 용출속도는 Gd과 Ce의 경우, 각각 $3.1{\times}10^{-4}{\sim}1.3{\times}10^{-6}g/m^2/day$ 및 $1.8{\times}10^{-3}{\sim}0g/m^2/day$었다. 결과적으로 이들 산성과 알칼리성 조건에서의 고화체의 용출속도는 차후 고화체의 화학적 내구성에 대한 척도로써 유용하게 사용될 수 있을 것으로 사료된다.

• E2M - 전기 전자와 첨단 소재
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• 제10권6호
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• pp.555-561
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• 1997

The passivation of n-GaAs(100) surface has investigated by photoreflectance(PR). The surface of the sample was treated with the 0.001 N solution Se/NH$_4$OH. After the surface treatment, the samples were annealed between 400 to $700^{\circ}C$ in a $N_2$atmosphere for 10 min. The intensity of PR signal and period of Franz-Deldysh oscillation(FKO) gradually decreased as the annealing temperature increased. The surface electric field(E$_{s}$) of the sample annealed at $600^{\circ}C$ is obtained 1.34$\times$10$^{5}$ V/cm. This value is 1.97 times less than that of unannealed sample. It has found that the passivation of surface occurred when the surface of the sample had been treated with Se/NH$_4$OH solution and annealed from 500 to $600^{\circ}C$. This result could be due to activation of elemental Se on the surface. It has also found that the elemental Se of the surface diffused about 100 $\AA$ into the bulk GaAs when Se-treated sample was annealed at $600^{\circ}C$.>.

• 대한한의학원전학회지
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• 제20권1호
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• pp.39-48
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• 2007

The first chapter of the Oh Sib Young(五十營) explains that the length of the measurement of channels(脈度) is sixteen zahngs two cheocks(16丈2尺). The second chapter says that nourishing gi(營氣) circles around(周行) the whole body 50 times during 13,500 times of breathing in twenty-four hours. The third chapter explains that the total length reaches 810 zhangs(810丈) if it circles around 50 times. Through construction of word, comparison of annotation, investigation, literal translation, free translation, conclusion analysis of these ancient writings, the following results were obtained. In the second chapter, "twenty five bun(二十五分)" should be modified into "twenty bun one Ii six ho(二十分一釐六毫) " or "twenty bun and the rest(二十分有奇)", "forty bun(四十分)" should be changed into "forty bun sam Ii two ho(四十分三釐二毫)" or "forty bun and the rest", and "five su twenty bun(五宿二十分)" should be modified into "five su twenty one bun six li(五宿二十分六釐)" or "two hundred ten bun and the rest(二百十分有奇)" in order to clarify their meanings.

• Journal of Astronomy and Space Sciences
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• 제15권1호
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• pp.69-74
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• 1998

Two colour(B & V) photoelectric observations of EB-type eclipsing binary GO Cyg were carried out for 15 nights during October and December 1996. Three new times of minimum derived from our own observations are presented. With these and previously published times, the period variation is studied, and a continuous period increase of $dP/dt{\approx}1.51{\times}10^{-7}d/yr$ is estimated from the quadratic ephemeris.

• 대한환경공학회지
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• 제22권5호
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• pp.869-877
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• 2000

Phenanthrene과 benzo[a]pyrene으로 오염된 토양을 슬러리상에서 오존처리시 반응메커니즘을 조사하였다. 토양내 오존주입시 OH-radical의 생성과 반응에 있어서 유 무기물의 영향을 알아보기 위하여 단순화된 토양매질로써 baked sand(BS), sand(S), glass beads(GB)를 택하여 실험한 결과 제거속도가 BS>S>GB 순으로 나타났다. Radical scavenger 실험을 통하여 OH-radical의 발생경향을 살펴보았는데, BS의 경우 OH-radical의 생성으로 오존과의 직접반응과 더불어 제거효율이 22% 상승됨을 알 수 있었다. Humic acid의 초기농도를 0~5 ppm으로 증가시킴에 따라 반응속도상수(psuedo first-order rate constant: $k_o$)가 $1.37{\times}10^{-2}s^{-1}$에서 $0.53{\times}10^{-2}s^{-1}$으로 감소하였으며, S매질상에서 PAHs의 초기농도 10mg-PAHs/kg-soil의 80%를 제거하는데 소모되는 오존 주입량은 phenanthrene의 경우 $67.2mg-O_3/kg-soil$였고, benzo[a]pyrene의 경우 $48.0mg-O_3/kg-soil$로 산정되었다.

• 대한본초학회지
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• 제32권4호
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• pp.39-46
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• 2017

Objectives : This study aims to provide basic data about Portulacae Herba (PH) extracts as natural antioxidants by considering diverse antioxidant activities of PH depending on solvents. Methods : The samples of PH were pulverized, and A hot water and a 70% EtOH were stir-extracted for two hours three times repeatedly in a water bath with a temperature of 95 degrees and at room temperature respectively to measure 7 kinds of antioxidant activities. Results : There were significant differences in total phenol content, because the total phenol content of the 70% EtOH extract was higher than the hot water extract's, and the total flavonoid content of the 70% EtOH extract($4.40{\mu}g/mg$) was nearly 3.8 times higher than the hot water extract's($1.16{\mu}g/mg$). DPPH and ABTS radical scavenging activities were 70% EtOH extract showed a little higher activity than the hot water extract, and at a concentration of $500{\mu}g/mg$, the highest scavenging activity was found in the 70% EtOH extract, not in the control group. Hydroxyl radical and $Fe^{2+}$ chelatingactivities were slightly higher in hot water extract than in 70% EtOH extract, and increased in a dose-dependent manner. Nitrite scavenging activities increased dose-dependently in the hot water and the 70% EtOH extract, regardless of the pH level, and scavenging activity of the 70% EtOH extract was higher at pH 1.2 than at pH 3.0. Conclusions : In conclusion, it is thought that PH hot water and 70% EtOH extract have antioxidant activities, and can be used as natural antioxidants in future.