• 한국산림과학회지
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• 제105권1호
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• pp.108-114
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• 2016

감말랭이의 $SO_2$ 살균패드처리($SO_2$ 0, 0.5, 1, 2 g/kg)에 의한 저장 중 품질에 미치는 영향을 조사하였다. 저장기간 동안 $SO_2$ 살균패드처리는 감말랭이의 중량 및 수분감소율과 가용성 고형물 함량에 영향을 미치지 않았다. 그러나 색차는 저장 12주 후 무처리구에서 3.5로 가장 높은 반면, $SO_2$ 2 g/kg 처리구에서 2.0으로 가장 낮게 나타났다. 감말랭이의 갈변도는 저장 12주 후 무처리구에서 0.24 O.D.로 가장 높았으며, $SO_2$ 0.5 g/kg 처리구 0.22 O.D.와 $SO_2$ 1 g/kg 처리구 0.20 O.D., $SO_2$ 2 g/kg 처리구 0.17 O.D.순으로 나타났다. 부패율은 저장 12주 후 무처리구가 7.0%로 가장 높은 반면, $SO_2$ 1 g/kg 처리구와 $SO_2$ 2 g/kg 처리구는 부패가 전혀 진행되지 않았다. 모든 $SO_2$ 살균패드 처리구에서 감말랭이의 잔류 이산화황 농도는 20.3~44.3 ppm으로 안전한 범위에서 검출되었다. 따라서 $SO_2$ 살균패드처리는 감말랭이의 갈변 및 부패를 억제시킴을 확인하였으며 특히, $SO_2$ 2 g/kg 처리가 감말랭이의 품질유지와 저장성에 가장 효과적이라고 판단된다.

• 한국대기환경학회지
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• 제26권5호
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• pp.543-553
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• 2010

Almost five million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan. As the subway system is typically a closed environment, indoor air pollution problems frequently occurs and passengers complain of mal-health impact. Especially $PM_{10}$ is well known as one of the major pollutants in subway indoor environments. The purpose of this study was to compare the indoor air quality in terms of $PM_{10}$ and to quantitatively compare its source contributions in a Seoul subway platform before and after installing platform screen doors (PSD). $PM_{10}$ samples were collected on the J station platform of Subway Line 7 in Seoul metropolitan area from Jun. 12, 2008 to Jan. 12, 2009. The samples collected on membrane filters using $PM_{10}$ mini-volume portable samplers were then analyzed for trace metals and soluble ions. A total of 18 chemical species (Ba, Mn, Cr, Cd, Si, Fe, Ni, Al, Cu, Pb, Ti, $Na^+$, $NH_4^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, and ${SO_4}^{2-}$) were analyzed by using an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the source of particulate matters. $PM_{10}$ for the station was characterized by three sources such as ferrous related source, soil and road dust related source, and fine secondary aerosol source. After installing PSD, the average $PM_{10}$ concentration was decreased by 20.5% during the study periods. Especially the contribution of the ferrous related source emitted during train service in a tunnel route was decreased from 59.1% to 43.8% since both platform and tunnel areas were completely blocked by screen doors. However, the contribution of the fine secondary aerosol source emitted from various outside combustion activities was increased from 14.8% to 29.9% presumably due to ill-managed ventilation system and confined platform space.

• 한국재료학회지
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• 제24권12호
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• pp.671-676
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• 2014

It is known that bones get damaged by accidents and aging. Since the discovery of Bioglass, various kinds of ceramics have been also found to bond to living bone; some of these ceramics are already being clinically used as bone-repairing materials. In the present study, antibacterial calcium silicate gel ($Ag-30CaO{\cdot}70SiO_2$ gel) was prepared by sol-gel method in order to control the microstructure, which is related to the dissolution rate and induction period of apatite formation in body environment. In addition, biological $Ag-30CaO{\cdot}70SiO_2$ is tested. This was done to impart antimicrobial activity to the $30CaO{\cdot}70SiO_2$. Ag ion was added during sol-gel synthesis to replace the $H_2O$ added during the making of the $30CaO{\cdot}70SiO_2$ gel, which has silver solutions of various concentration. After the sol-gel process, 1N-$HNO_3$ solution was used to wash the gel when synthesizing the gel, in order to maintain the porous structure and remove PEG, water soluble polymers. Then, the apatite forming ability of the sol-gel derived CaO-$SiO_2$ gels was investigated using simulated body fluid (SBF), which had almost the same ion concentration as that of human blood plasma. The gels were analyzed by FT-IR spectroscopy, SEM observation, XRD, and fluorescent microscopy. The apatite was successfully created even after washing the gel; apatite is present in an amorphous state, and was found to affect the concentration of the Ag ion in cells in MC3T3 live & dead assay results. From these results, it is suggested that a good material that can be used to repair defects of nature bone is $Ag-30CaO{\cdot}70SiO_2$ gel.

• 한국재료학회지
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• 제21권2호
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• pp.111-114
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• 2011

As a growth-template of ZnO nanorods (NR), a hexagonal $\beta-Ni(OH)_2$ nanosheet (NS) was synthesized with the low temperature hydrothermal process and its microstructure was investigated using a high resolution scanning electron microscope and transmission electron microscope. Zinc nitrate hexahydrate was hydrolyzed by hexamethylenetetramine with the same mole ratio and various temperatures, growth times and total concentrations. The optimum hydrothermal processing condition for the best crystallinity of hexagonal $\beta-Ni(OH)_2$ NS was determined to be with 3.5 mM at $95^{\circ}C$ for 2 h. The prepared $Ni(OH)_2$ NSs were two dimensionally arrayed on a substrate using an air-water interface tapping method, and the quality of the array was evaluated using an X-ray diffractometer. Because of the similarity of the lattice parameter of the (0001) plane between ZnO (wurzite a = 0.325 nm, c = 0.521 nm) and hexagonal $\beta-Ni(OH)_2$ (brucite a = 0.313 nm, c = 0.461 nm) on the synthesized hexagonal $\beta-Ni(OH)_2$ NS, ZnO NRs were successfully grown without seeds. At 35 mM of divalent Zn ion, the entire hexagonal $\beta-Ni(OH)_2$ NSs were covered with ZnO NRs, and this result implies the possibility that ZnO NR can be grown epitaxially on hexagonal $\beta-Ni(OH)_2$ NS by a soluble process. After the thermal annealing process, $\beta-Ni(OH)_2$ changed into NiO, which has the property of a p-type semiconductor, and then ZnO and NiO formed a p-n junction for a large area light emitting diode.

• 원예과학기술지
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• 제28권4호
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• pp.552-560
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• 2010

$GA_{4+7}$+BA는 유목의 측지 발생 및 과실비대를 목표로 사용되는 생장조절제로써 본 실험에서는 밀식 과수원의 '갈라' 사과품종을 공시하여 4년 동안 여러 가지 살포방법을 이용하여 과실비대 및 영양생장에 미치는 영향을 조사하였다. $GA_{4+7}$+BA 처리시 과실 종경, 과중, L/D율은 증가되나 가용성 고형물 함량 및 산 함량, 엽면적, 엽록소함량 등은 변화가 일정하지 않았다. 과실 내 종자 수는 처리에 따른 차이가 없었으나 미발육 종자의 수가 증가하는 것으로 나타났다. 고농도 수관전체 살포는 신초생장을 증가시켰으나 착과 부위에만 살포시에는 영향이 없었다. 살포시기에 있어서는 과실 세포분열이 끝나는 시점인 5월말에서 6월초에 살포하는 것이 과실비대에 가장 효과적이었다. 그러나 고농도 $GA_{4+7}$+BA처리는 과실의 경도를 감소시켜 과실의 저장성을 떨어뜨리기 때문에 '갈라' 같은 소과종에 있어 고농도의 $GA_{4+7}$+BA 살포는 주의가 필요할 것으로 판단되었다.

• 원예과학기술지
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• 제19권3호
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• pp.367-372
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• 2001

포도 거봉(Vitis labruscana L 'Kyoho')은 연 2회 생산할 수 있는 2기작 재배가 가능하다. 그러나 2기작 재배에서 2차 생산을 위한 과실의 성숙기가 단일조건과 저온기에 해당하므로 고품질의 과실 생산에 제약이 되고 있다. 거봉 수체의 생장을 촉진하고 과실의 품질을 향상시키기 위하여 근권제한 재배용 베드에 온수파이프를 설치한 후 지중 가온에 의한 근권온도 상승 및 플라스틱 온실 내 $CO_2$ 시용에 따른 생장과 과실의 품질 특성을 조사하였다. 신초 절간장, 엽면적 및 엽 건물중은 $CO_2$ 시용에 관계없이 근권온도 상승구에서 양호하였다. 과방중, 과립중, 산함량, 착색도 및 화진은 처리간 차이가 없었으나, 당 함량은 근권온도 상승 처리구와 근권온도 상승＋$CO_2$ 공급구에서 유의하게 높았다. $CO_2$ 농도가 $300{\mu}mol{\cdot}mol^{-1}$에서 $800{\mu}mol{\cdot}mol^{-1}$로 증가함에 따라 광합성 속도가 계속 증가하였으나, $800{\mu}mol{\cdot}mol^{-1}$ 이상의 농도에서 광합성 속도의 변화는 크지 않았다. 흐린 날에는 $CO_2$ 시용에도 불구하고 온실 내의 낮은 광량과 저온으로 인하여 광합성 속도가 증가하지 않았다.

• 한국대기환경학회지
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• 제29권1호
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• pp.74-85
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• 2013

Since the underground transportation system is a closed environment, indoor air quality problems may seriously affect many passengers' health. The purpose of this study was to understand $PM_{10}$ characteristics in the underground air environment and further to quantitatively estimate $PM_{10}$ source contributions in a Seoul Metropolitan subway station. The $PM_{10}$ was intensively collected on various filters with $PM_{10}$ aerosol samplers to obtain sufficient samples for its chemical analysis. Sampling was carried out in the M station on the Line-4 from April 21 to 28, July 13 to 21, and October 11 to 19 in the year of 2010 and January 11 to 17 in the year of 2011. The aerosol filter samples were then analyzed for metals, water soluble ions, and carbon components. The 29 chemical species (OC1, OC2, OC3, OC4, CC, PC, EC, Ag, Al, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Si, Ti, V, Zn, $Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were analyzed by using ICP-AES, IC, and TOR after proper pretreatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the $PM_{10}$ sources and then six sources such as biomass burning, outdoor, vehicle, soil and road dust, secondary aerosol, ferrous, and brakewear related source were classified. The contributions rate of their sources in tunnel are 4.0%, 5.8%, 1.6%, 17.9%, 13.8% and 56.9% in order.

• 한국산림과학회지
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• 제105권2호
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• pp.202-207
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• 2016

곶감의 $SO_2$ 발생패드처리(SO2 0, 0.5, 1, 2 g/kg)에 의한 저장 중 품질에 미치는 영향을 조사한 결과, 저장기간동안 $SO_2$ 발생패드처리는 곶감의 중량 및 수분감소율과 가용성 고형물 함량에 영향을 미치지 않았다. 그러나 저장 12주 후 곶감 표면의 색차(E)는 무처리구에서 3.5로 가장 높은 반면, $SO_2$ 2 g/kg 처리구에서 2.6으로 가장 낮게 나타났다. 곶감의 갈변도는 저장 12주 후 무처리구에서 0.15 O.D.로 가장 높았으며, $SO_2$ 0.5 g/kg 처리구 0.14 O.D.와 $SO_2$ 1 g/kg 처리구 0.10 O.D., $SO_2$ 2 g/kg 처리구 0.05 O.D.순으로 나타났다. 부패율은 저장 12주 후 무처리구가 9.0%로 가장 높은 반면, $SO_2$ 2 g/kg 처리구는 부패가 전혀 발생되지 않았다. 모든 $SO_2$ 발생패드 처리구에서 곶감의 잔류 이산화황 농도는 3.3~97.0 ppm으로 안전한 범위에서 검출되었다. 따라서 $SO_2$ 발생패드처리는 곶감의 갈변 및 부패를 억제시킴을 확인하였으며 특히, $SO_2$ 2 g/kg 처리가 곶감의 품질유지와 저장성에 가장 효과적이라고 판단된다.

• 한국대기환경학회지
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• 제25권4호
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• pp.275-288
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• 2009

The Korean government strengthened the environmental polices to manage and enhance Metropolitan Area air quality, and also has enforced "Special Act on Seoul Metropolitan Air Quality Improvement (SASMAQI)" issued in Dec. 2004. Recently government expanded the Seoul Metropolitan Air Quality Management District (SMAQMD) to the outskirts satellite cities of Seoul area through the "Revised Law Draft of SASMAQI". The SMAQMD has been alloted the allowable emission loads to the local governments on the basis of the carrying $PM_{10}$ capacity. However, in order to establish the effective air quality control strategy for $PM_{10}$, it is necessary to understand the corresponding sources which have a potential to directly impact ambient $PM_{10}$ concentration. To deal with the situations, many receptor methodologies have been developed to identify the origins of pollutants and to determine the contributions of sources of interests. The objective of this study was to extensively identify $PM_{10}$ sources and to estimate their contributions at the metropolitan area. $PM_{10}$ samples were simultaneously collected at the 3 semi-industrialized local cities in the Seoul metropolitan area such as Hwasung-si, Paju-si, and Icheon-si sites from April 15 to May 31, 2007. The samples collected on the teflon membrane filter by one $PM_{10}$ cyclone sampler were analyzed for trace metals and soluble ions and samples on the quartz fiber filter by another sampler were analyzed for OC and EC. Source apportionment study was then performed by using a positive matrix factorization (PMF) receptor model. A total of 6 sources were identified and their contributions were estimated in each monitoring site. Contribution results on Hwasung, Paju, and Icheon sites were as follows: 33%, 27%, and 27% from soil source, 26%, 26%, and 21% from secondary aerosol source, 11%, 11%, and 12% from biomass burning, 12%, 6%, and 5% from sea salt, 7%, 15%, and 19% from industrial related source, and finally 11%, 15%, and 16% from mobile and oil complex source, respectively. This study provides information on the major sources affecting air quality in the receptor sites and thus it will help to manage the ambient air quality in the metropolitan area by establishing reasonable control strategies, especially for the anthropogenic emission sources.

• 한국대기환경학회지
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• 제24권5호
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• pp.501-511
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• 2008

The Objective of this study is to examine the characteristic of fine aerosol $(PM_{2.5})$ obtained at Ieodo Ocean Research Station, which lies between the eastern part of China and the south western part of Korea. The average mass concentration of $PM_{2.5}$ was $21.5{\pm}17.0{\mu}g/m^3$ during June $2004{\sim}June 2006$. The concentration was the highest in winter $(34.8{\mu}g/m^3)$ and lowest in summer $(16.5{\mu}g/m^3)$. Water soluble ions were measured for samples collected from December 2004 to September 2005. Among them, $SO_4^{2-}\;and\;NH_4^+$ were the most abundant species and accounted for 32.2% and 14.2% of the $PM_{2.5}$ mass, respectively. The mass fraction of $SO_4^{2-}$ was higher in winter (42%) than in spring (26%). Nitrate concentrations were much lower than those of sulfate due mainly to evaporation during sampling period. The cluster analysis of backward airmass trajectories showed that the high mass loadings $(26.9{\mu}g/m^3\;on\;average)$ were associated with air originating inland China. Also, the seasonal variation of $PM_{2.5}$ mass was well correlated with the frequency of westerly winds passing through the western part of China. During the ABC-EAREX2005 (March 2005), $PM_{2.5}$ mass and major ionic concentrations were higher at Ieodo, compared with $PM_{2.5}$ measurements at Gosan while they were similar in variation pattern. These results suggested that $PM_{2.5}$ mass and its ionic composition of Ieodo Ocean Research Station were greatly influenced by continental outflows from China.