• 센서학회지
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• 제1권1호
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• pp.59-66
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• 1992

$BaSO_{4}$ : Eu 열형광체 분말을 제작하고 이를 PTFE로 중합한 디스크형의 $BaSO_{4}$ : Eu-PTFE 고감도 TLD 방사선 센서를 제작하였다. $BaSO_{4}$ : Eu 열형광체는 $BaSO_{4}$분말과 활성체인 Eu($Eu_{2}O_{3}$) 및 두가지 용제 $NH_{4}Cl$과 $(NH_{4})_{2}SO_{4}$를 각각 lmol%, 6mol% 및 5mol%의 농도로 묽은 황산에 공침하여 건조시킨 후 질소분위기에서 $1000^{\circ}C$로 1시간 동안 소결하여 제작하였을 때 $X/{\gamma}$선에 대해 최대감도를 나타내었다. 그리고 $BaSO_{4}$ : Eu glow 곡선의 주 피이크의 활성화에너지와 진동수인자 및 발광차수는 각각 1.17eV, $3.6{\times}10^{11}/sec$ 및 1.25이었으며, 발광 스펙트럼의 피이크 파장은 425nm였다. 한편 $BaSO_{4}$ : Eu-PTFE TLD의 최적제작조건은 열형광체 분말의 함량은 40wt%, TLD의 두께는 $105.7mg/cm^{2}$ 중합조건은 $380^{\circ}C$, 공기중에서 2시간으로 결정하였다. 그리고 ${\gamma}$선에 대한 TL 피이크 강도의 선량의존성은 0.01-20Gy영역에서 선형적이었으며, 감쇠율은 60시간에 약 10 %였다.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1265-1272
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• 2007

A solid acid catalyst, NiSO4/CeO2-ZrO2 was prepared simply by promoting ZrO2 with CeO2 and supporting nickel sulfate on CeO2-ZrO2. The support of NiSO4 on ZrO2 shifted the phase transition of ZrO2 from amorphous to tetragonal to higher temperatures because of the interaction between NiSO4 and ZrO2. The surface area of 10-NiSO4/1-CeO2-ZrO2 promoted with CeO2 and calcined at 600 oC was very high (83 m2/g) compared to that of unpromoted 10-NiSO4/ZrO2 (45 m2/g). This high surface area of 10-NiSO4/1-CeO2-ZrO2 was due to the promoting effect of CeO2 which makes zirconia a stable tetragonal phase as confirmed by XRD. The role of CeO2 was to form a thermally stable solid solution with zirconia and consequently to give high surface area and acidity of the sample, and high thermal stability of the surface sulfate species. 10-NiSO4/1- CeO2-ZrO2 containing 1 mol% CeO2 and 10 wt% NiSO4, and calcined at 600 oC exhibited maximum catalytic activities for both reactions, 2-propanol dehydration and cumene dealkylation.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2002년도 봄 학술발표대회 발표논문집
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• pp.475-476
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• 2002

$SO_2$ 폭로군의 기관 상피층의 섬모에서 DBA 및 SBA는 50ppm 이하 $SO_2$ 폭로군에서는 대조군에 비해 증가하였으며 sWGA 및 UEA-1은 대부분의 $SO_2$ 폭로군에서 대조군에 비해 증가하였다. 섬모세포에서 LCA 및 Con A는 100ppm 및 200ppm $SO_2$ 폭로군에서 대조군에 비해 약간 증가하였다. 배상세포에서는 대부분의 렉틴의 반응성이 50ppm 이하의 $SO_2$ 폭로군에서는 증가하였다가 100ppm 및 200 ppm $SO_2$ 폭로군에서는 현저히 감소하였다. 장액선포에서는 LCA 및 Con A는 모든 $SO_2$ 폭로군에서 대조군보다 증가하는 경향을 보였으며 점액선포에서는 대조군에서 관찰되지 않았던 RCA-1은 50ppm 및 100ppm $SO_2$ 폭로군의 일부 선포에서 증가하였다. 위의 결과로 보아 $SO_2$는 기관에 심대한 병리조직학적 변화뿐만 아니라 glycoconjugates대사에 심대한 영향을 미쳐 심한 병변을 야기시킴을 알 수 있었다. 전반적으로 $SO_2$의 호흡기 영향은 고농도로 갈수록 심한 영향을 나타내었다. 저농도에서도 폭로 시간이 길어짐에 따라 나타나는 $SO_2$의 영향이 고농도와 유사한 경향을 나타내며 또한 모든 $SO_2$의 농도를 비교해보면 폭로 시간이 길어질수록 그 영향이 더 심하게 나타났다.

• 아시아태평양코퍼스연구
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• 제1권2호
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• pp.27-39
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• 2020

This paper examines the frequency and distribution of the so-called "non-discourse marker functions" of so in essay writings produced by 200 L1 English speakers and 1,300 EFL learners in China, Japan, Korea, and Taiwan. Based on the data drawn from the International Corpus Network of Asian Learners of English, this study compares EFL learners and L1 English speakers' uses of so, identifying four grammatical uses, as (1) an adverb, (2) part of a fixed phrase, (3) a pro-form, and (4) a conjunction phrase specifying purpose. This study aims to show the wide variability among EFL learners with different L1s, identifying the tendency of usage both common among and specific to the sub-groups of EFL learners. The findings suggest that the learners demonstrate patterns distinctively different from those of L1 English speakers, indicating an underuse of so as a marker expressing "purpose" and an overuse as part of fixed phrases. Compared to L1 English speakers, the learners also tend to overuse so in the discourse marker functions, regardless of their L1s. The study proposes pedagogical implications focusing on discourse flow and diachronic aspects of so in order to understand its multifunctionality, although the latter is primarily suggested for advanced learners.

• 한국환경과학회지
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• 제16권2호
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• pp.187-195
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• 2007

Long-term passive diffusive samplers(PDS) have been used to measure $NO_2\;and\;SO_2$ concentrations at 21 sampling sites in Daejeon, Korea during the period of January 2000 - December 2002. The spatial distributions of annual $NO_2\;and\;SO_2$ concentrations were mapped. Average annual $NO_2$ concentration over the sampling period was $28.5{\pm}12.5\;ppb$, ranging from 1.2 to 81.7 ppb. Average annual $SO_2$ concentration over the sampling period was $7.7{\pm}4.8\;ppb$, ranging from 0.6 to 26.8 ppb. On average, $NO_2$ concentration was approximately 5.8%(1.6 ppb) larger in 2002. $SO_2$ concentration was decreased by 13%(1.1 ppb) during the sampling period. The seasonal variation of $NO_2\;and\;SO_2$ concentration was observed with a tendency to be higher in fall and winter. $NO_2\;and\;SO_2$, concentrations measured at different site types(patterns of land use) show significant difference. The observed difference in concentration was associated with difference in emissions of $NO_2$ from motor vehicles and $SO_2$ by non-traffic fuel consumption for heating.

• 시멘트
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• 통권51호
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• pp.20-30
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• 1973

1) electron-microprobe를 응용하여 $CaO-SiO_2-Al_2O_3$ 계에서 생성한 $C_2S$, $C_3S$ 에 존재하는 sulfate의 solid, solution을 정량적으로 구할 수 있었으며 이 결과로 $C_2S$ 에 $Al_2O_3$, $SO_3$ 등이 solid soln 등으로 침적되고 이들이 $C_3S$의 생성을 억제한다는 mechanism이 확인되었다. 2) phase equilibrium(상평형)에 의하면 $Na_2SO_4$, $K_2SO_4$는 mineralizer로서 작용하며 $C_3S$ 의 생성을 돕는다. 그러나 $K_2SO_4$ 와 $Al_2SO_3$ 가 결합상태로 존재할 경우는 1,400 $^{\circ}C$에서 광범위한 liquid를 생성하며 quenching하면 glass질과 $\beta-C_2S$ 만이 얻어지고 $C_3S$ 는 생성되지 않는다. 또 이를 1,250 $^{\circ}C$ 까지 서냉하면 $C_2S$ 와 Ca, K, Al, S, 등을 함유한 새로운 물질이 생성된다. 3) $CaO-SiO_2-Al_2O_3-Fe_2O_3$ 계에서 $C_3S$ 의 생성에 미치는 $Na_2SO_4$, $K_2SO_4$ 의 영향을 실험실적으로 검토한 결과 complex interaction이 확인되었으며 $Na_2SO_4$ 는 어떤 경우에는 mineralizing effect를 상실한다는 재미 있는 사실이 발견되었다.

• 농업과학연구
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• 제51권2호
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• pp.123-132
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• 2024

Copper sulphate (CuSO₄) level was analyzed in this study to determine the effects on growth performance, nutrient digestibility, organ weight, and excreta score in Ross308-broilers. A total of 1,134 mixed sex, 1-d old Ross-308 chicks were randomly allocated to one of three treatment groups with 21 replication and 18 chicks / cage. For a period of 32 days, chicks were fed with the following treatment groups: CON: Basal diet, TRT1: 0.032% CuSO₄, TRT2: 0.047% CuSO₄ (Phase 1), 0.032% CuSO₄ (Phase 2), 0.025% CuSO₄ (Phase 3). The experiment was divided into three phases. Phase 1 (day 1 to 9), phase 2 (day 9 to 21), and phase 3 (day 21 to 32). During days 1 to 9, broilers receiving 0.032% or 0.047% of CuSO₄ in TRT1 and TRT2, respectively, had significantly higher body weight gain (BWG) (p = 0.042) than CON. Likewise, comparing TRT1 and TRT2 to CON during days 10 to 21, 0.032% of CuSO₄ significantly increased BWG (p = 0.013) and feed intake (FI), (p = 0.024) in the broiler. When compared to TRT1, the administration of 0.032% and 0.025% of CuSO₄ during days 22 to 32 reduced BWG and FI in CON and TRT2, respectively among the treatment groups. Throughout the experiment, the feed conversion ratio (FCR) did not change. However, the nutrient digestibility, weight of organs, and the score of excreta remained unchanged. The study found that CuSO₄ administration increased broiler BWG and FI without affecting FCR, nutrients digestibility, weight of organs, and excreta score.

• 한국환경농학회지
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• 제6권2호
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• pp.73-76
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• 1987

들깨 수원(水原) 8호(號)(Perilla frutescens Suwon No. 8)에 $SO_2$를 접촉(接觸)시켰을 때 일어나는 광합성색소(光合成色素)의 변화(變化)에 대(對)한 $SO_2$농도(濃度), 접촉시간(接觸時間), 광,(光) 활성산소(活性酸素)와 무기(無機) $SO_3\;^{-2}$의 영향(影響)을 관찰분석(觀察分析)한 결과(結果)는 다음과 같다. 1. $SO_2$농도(濃度)가 높아지고 접촉시간(接觸時間)이 길어질수록 피해(被害)가 심해저 엽록소(葉綠素)의 파괴(破壞)도 많았다. 2. $SO_2$ gas접촉에 의하여 엽록소(葉綠素)a가 엽록소(葉綠素)b 보다 쉽게 분해(分解)되었으며 또한 carotinoid도 엽록소(葉綠素)b보다 쉽게 분해(分解)되는 것으로 추정된다. 3. 들깨의 $SO_2$에 의한 엽록소파괴(葉綠素破壞)는 $SO_2$에 의한 직접적(直接的)인 영향(影響)으로 파악되었고, 이 때에 광(光)이 필수적(必須的)으로 필요하며, 물이 광분해(光分解)로 생성(生成)되는 $O_2^-$가 $SO_2$와 함께 엽록소분해(葉綠素分解)에 중심적(中心的)인 역할을 하는 물질이었다.

• Corrosion Science and Technology
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• 제19권1호
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• pp.43-50
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• 2020

In this study, the effects of KCl(s) and K₂SO₄(s) on the oxidation characteristics of 2.25Cr-1Mo steel were investigated for 500 h in 10O₂ + 10CO₂ (vol%) gas environmen at 650 ℃. Oxidation kinetics were characterized by weight gain, oxide layer thickness, and fitted models for the experiment data were proposed. The fitted models presented considerable agreement with the experimental data. The oxide layer was analyzed using the scanning electron microscope, optical microscope, and energy dispersive X-ray spectroscopy. The oxidation kinetics of 2.25Cr-1Mo steel with KCl and K₂SO₄ coatings showed significantly different oxidation kinetics. KCl accelerated the oxidation rate very much and had linear oxidation behavior. In contrast, K₂SO₄ had no significant effect, which had parabolic kinetics. The oxide layer was commonly composed of Fe₂O₃, Fe₃O₄, and FeCr₂O₄ spinel. KCl strongly accelerated the oxidation rates of 2.25Cr-1Mo steel in the high-temperature oxidation environment. Conversely, K₂SO₄ had little effect on the oxidation rates.

• 한국환경보건학회지
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• 제17권2호
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• pp.1-8
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• 1991

The stochastic variance and structures of time series data on air quality were examined by employing the techniques of autocorrelation function, variance spectrum, fourier series, ARIMA model. Among the air quality properties of atmosphere, SO$_{2}$ is one of the most siginificant and widely measured parameters. In the study, the air quality data were included hourly observations on SO$_{2}$ TSP and O$_{3}$. The data were measured by automatic recording instrument installed in Kwanghwamoon during February and March in 1991. The results of study were as follows 1. Hourly air quality series varied with the domiant 24 hour periodicity and the 12 hour periodic variation was also observed. 2. The correlation coefficients between SO$_{2}$ and O$_{3}$ is -0.4735. 3. In simulating or forecasting variation in SO$_{2}$ ARIMA models are on a useful tools. The multiplicative seasonal ARIMA (1, 1, 0) (0, 2, 1)$_{24}$ model provided satisfactory results for hourly SO$_{2}$ time series.