제주도 지하수 질산염 농도의 시·공간적 변화 특성: 장기(1993-2015) 모니터링 자료의 평가

김호림(Ho-Rim Kim),오준섭(Junseop Oh),도현권(Hyun-Kwon Do),이경진(Kyung-Jin Lee),현익현(Ik-Hyun Hyun),오상실(Sang-Sil Oh),감상규(Sang-Kyu Kam),윤성택(Seong-Taek Yun) 대한자원환경지질학회 2018 자원환경지질 Vol.51 No.1

1993년부터 2015년까지 관측된 제주도 지하수 장기모니터링 관측정(N = 4,835)에서 수집된 지하수 수질자료(N = 21,568)를 기반으로 질산성질소의 시공간적 변동 특성을 평가하였다. 제주도 지하수의 질산성질소 농도의 중앙값은 2.5 mg/L로서 다른 국가나 대륙의 조사 결과에 비해 다소 높거나 유사한 것으로 나타났다. 또한 지하수 용도, 행정구역 및 고도 별로 유의한 차이를 보였다. 특히, 산간 지역에 비해 저지대 해안가에 위치한 농업 및 주거지역에서 농도가 높음을 확인하였다. Mann-Kendall 및 Sen’s slope 분석을 활용한 질산성질소 농도의 추세 분석 결과, 하류 저지 대에 비해 중산간지역에서의 질산성질소 농도 증가 경향이 뚜렷하였다. 제주도 내 토지 피복의 시계열 변화 특성과 결부 지어 보면, 중산간지역의 오염 증가 추세는 농업지역의 확장 등 인위적 활동 증가에 기인한 결과로 판단된다. 반면,기지정된 지하수자원특별관리구역에서는 전반적으로 질산성질소 농도의 감소 경향이 나타났는데, 이는 지하수 관리 측면에서 수질관리를 위한 적극적인 정책이 유효함을 시사한다. 본 연구에서는 제주도 지하수의 질산성질소 오염관리를 위한 적정 방안을 제안한다. The spatio-temporal variations of nitrate concentrations in groundwater of Jeju Island were evaluated by an analysis of time series groundwater quality data (N = 21,568) that were collected from regional groundwater monitoring (number of wells = 4,835) for up to 20 years between 1993 and 2015. The median concentration of NO 3 -N is 2.5 mg/L, which is slightly higher than those reported from regional surveys in other countries. Nitrate concentrations of groundwater in wells tend to significantly vary according to different water usage (of the well), administrative districts, and topographic elevations: nitrate level is higher in low-lying agricultural and residential areas than those in high mountainous areas. The Mann-Kendall trend test and Sen’s slope analysis show that nitrate concentration in mid-mountainous areas tends to increase, possibly due to the expansion of agricultural areas toward highland. On the other hand, nitrate concentrations in the Specially Designated Groundwater Quality Protection Zones show the temporally decreasing trend, which implies the efficiency of groundwater management actions in Jeju. Proper measures for sustainable groundwater quality management are suggested in this study.

A Narrative Research Study: Implementing Portfolios as Comprehensive Assessment

윤도현 ( Do Hyun Yun ) 21세기영어영문학회 2010 영어영문학21 Vol.23 No.4

The purpose of this qualitative research study is to analyze how portfolios can be implemented as comprehensive assessment. Portfolios provide today`s educators with a viable means of measuring student knowledge within the framework of the life experiences and the values of learners. Through narratives from two participants, Hyun and David, this study gives English teachers in Korea valuable information about how portfolio assessment can make up for the weak points in the existing standardized tests. The findings say that for a key to success in implementing portfolios as an assessment strategy, we need thoughtful consideration about the contents taken from Hyun`s and David`s perspectives within the particular purposes and social contexts of schools.

복합섬유 보강 고인성 시멘트 복합체의 인장거동

윤현도,양일승,한병찬,福山洋,전에스더,문연준 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

An overview of the response highly ductile hybrid fiber reinforced cementitious composites to bending loading, direct tensile loading, and cyclic loading in both tension and compression is presented. Hybrid fiber reinforced cement composites(HFHCC) contains both of specially processed steel fiber( steel cord) and synthetic fiber. such as. Polyethylene(PE) and Polyvinyl alcohol(PVA). As the result of the bending tests. HFHCC specimen shows multiple cracking in the area subjected to the greatest bending tensile stress. Uniaxial tensile test confirms the range of tensile strain capacity from 0.5 to 1.5% when hybrid fiber is used. The cyclic loading test results identified a unique unloading and reloading response for this ductile composite. Cyclic loading in tension appears not to affect the tensile response of the material if the uniaxial compressive strength during loading is not exceeded.

Lipomyces starkeyi KSM 22 Glucanhydrolase 함유 용액의 치은 섬유아세표에 대한 영향

윤현정,정현주,김옥수,김도만 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.3

A novel glucanhydrolase from a mutant of Lipomyces starkeyi KSM 22 has additional amylase activity besides mutanolytic activity and has been suggested as promising anti-plaque agent. It has been shown effective in hydrolysis of mutan, reduction of mutan formation by Streptococcus mutans and removal pre-formed sucrose-dependent adherent microbial film and has been strongly bound to hydroxyapatitie. These in vitro properties of Lipomyces starkeyi KSM 22 glucanllydrolase are desirable for its application as a dental plaque control agent. In human experimental gingivitis model and 6month clinical trial. mouthrinsing with Lipomyces starkeyi KSM 22 dextranase was comparable to 0.12% chlorhexidine mouthwash in inhibition of plaque accumulation and gingival inflammation and local side effect was negligible. This study was aimed to evaluate the cytotoxic effect of Lipomyces starkeyi KSM 22 glucanhydrolase on human gingival fibroblasts. Primary culture of human gingival fibroblasts at the 4th to 6th passages were used. Glucanhydrolase solution was made from lyophilized glucanhydrolase powder from a mutant of Lipomyces starkeyi KSM 22 solved in PBS and added to DMEM to the final concentration of 0.5, 1, and 2unit. Cells were exposed to glucanhydrolase solution or 0.1% chlorhexidine and the cells cultured in DMEM with 10% FBS and 1% antibiotics as control. After exposure, the morphological change, cell attachmcnt. and cell activity by MTT assay were evaluated in 0.5, 1.5, 3, 6, 24 hours after treatment. The cell proliferation and cell activity was also evaluated at 2 and 7days after Iminute exposure, twice a day. The cell morphology was similar between the Lipomyces starkeyi KSM 22 glucanllydrolase groups and control group during the incubation periods. while most fibroblasts remained as round cell regardless of incubation time in the chlorhexidine group. The numbers of the attached cells in the glucanhydrolase groups were comparable to that of control and significantly higher than the chlorhexidine group. The numbers of the proliferated cells in the glucanhydrolase groups at 7 days of incubation were comparable to the control group and higher than the chlorhexidine group. The cell activity in glucanhydrolase groups paralleled with the increased cell number by attachment and proliferation. According to these results, Lipomyces starkeyi KSM 22 glucanhydrolase has little harmful effect on attachment and proliferation of human gingival fibroblasts, in contrast to 0.1% chlorhexidine which was cytotoxic to human gingival fibroblasts. Therefore this glucanhydrolase preparation is considered as a safe and promising agent for new mouthwash formula in the near future.

개구부를 갖는 철근콘크리트 바벨형 전단벽의 전단강도와 변형능력

윤현도,최창식 대한건축학회 2005 大韓建築學會論文集 : 構造系 Vol.21 No.3

Shear strength and deformability of reinforced concrete(R/C) framed shear wall with opening were investigated based on available experimental date. Results of 61 tests of R/C framed shear walls with opening were reviewed to evaluate the current design provisions (Architectural Institute of Japan guideline and ACI 318-02) for nominal shear strength. The results indicate that procedures defined in chapter 21(21.7.4) of ACI 318-02 were found to overestimate the shear strength of shear walls with opening while AIJ guideline tended to underestimate that. A reasonable average lower bound to the shear strength of R/C shear walls with opening is found to be 0.34root(f_cu)MPa While deformability of shear walls with opening reduces with increasing opening periphery ratio, it increases with increasing the product of area ratio and strength of horizontal reinforcement. The magnitude of axial stress and shear stress had a insignificant effect on the deformability of shear walls with opening.

전단보강근량에 따른 초고강도 콘크리트를 사용한 고층형 내력벽의 이력거동

윤현도,연길환,정수영,윤석천,이창갑 忠南大學校 産業技術硏究所 1995 산업기술연구논문집 Vol.10 No.1

Three one fourth scale models using ultra high-strength concrete(f' =704 kg/㎠) are tested under the combined action of a constant axial and a horizontal load cyclically to failure. Such specimens are considered to represent the critical 3-story of low part in 60-story tall building of a structural wall system in area of high seismicity. The amount of vertical reinforcement and the level of applied axial stress are identical for the three wall tested. The cross-section of all walls is barbell shape. The aspect ratio(h /l ) of test specimen is 1.8. The primary objectives of this paper are to investigate the influence of the amount of horizontal reinforcement on the lateral resistance, failure mechanism, ductility and energy-dissipation capability of walls with ultra high-strength concrete. In contrast to what is widely believed, the horizontal web reinforcement does not appear to have a significant effect on shear capacity. Certainly, since the reduction of the web horizontal reinforcement to almost half the value specified by building codes doesn't affect the failure load, this effect in not accounted for by the truss analogy concept. The results obtained have helped to identify the causes of wall failure and have demonstrated that the concepts underlying current ACI Building Code provisions for the design of walls conflict with the observed structural behavior. It has been found that shear resistance is associated with triaxial compressive stress conditions that develop in the compressive zone of the section at the base of the wall.

剪斷補强되지 않는 高强度 輕量 콘크리트 보의 剪斷性能

윤현도 建陽大學校 2000 建陽論叢 Vol.- No.8

The use of lightweight of higher compressive strengths is increasing faster than the development of appropriate design recommendations. This paper reports limited experimental data on the shear performance of high-strength lightweight concrete beams without web reinforcement. Shear tests were conducted on nine reinforced beams. The variables were the type of aggregate and shear span ratio(a/d=1.5, 2.5, 3.5). Test results are presented in terms of load-deformation behavior, cracking patterns, and strength. It is concluded that the shear design provisions of the ACI318-95 Building Code are found to be adequate to predict the strength of reinforced high-strength lightweight concrete beams.

복합섬유 보강 고인성 시멘트 복합체의 특성

윤현도,양일승,한병찬,福山洋,전에스더,문연준 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

In this paper, workability, fiber dispersion. compressive strength and splitting strength of hybrid fiber reinforced cement composites(HFHCC) have been investigated by means of Korean Standard (KS). Two type of HFRCC were constructed using fiber combinations of Polyethylene(PE) and steel fibers. Polyvinyl alcohol(PVA) and steel fibers. Test results showed that the fibers, when used in a hybrid form. could result in superior composite performance compared to their individual fiber reinforced cement Composites. Synthetic micro fibers. such as PE and PVA. are effective at imparting fiber dispersion and ductility to the steel fiber (five twisted steel fiber) reinforced cement Composite.

6-(3,4-디클로로페닐)아미노-7-클로로-5,8-퀴놀린디온의 항진균작용 및 안전성 평가

윤여표,김동현,이병무,허문영,정해문,강혜영,최정아,김도희,유충규 성균관대학교 약학연구소 1998 成均藥硏論文集 Vol.10 No.1

6-(3.4-Dichlorophenyl)amino-7-chloro-5.8-quinolinedione (RCK50) was tested for antifungal activities in mice systemically infected with Candida albicans. The therapeutic potential of RCK50 was also assessed in comparison with ketoconazole. RCK50 had ED_50 0.22±0.01 ㎎/㎏. Ketoconazole as a positive control had ED_50 6.00±1.70 ㎎/㎏. Intraperitoneally administered RCK50 at the ED_50 for 7 days and 14 days reduced Candida albicans colony count in the kidneys and liver. And administered RCK50 at the ED_50 for 14 days improved survival rates. The genotoxicities of RCK50 had been evaluated. RCK50 was negative in Ames test with Salmonella typhimurium and chromosomal aberration test in CHL cells. RCK50 did not show any clastogenic effect in mouse peripheral blood and was negative in mouse micronucleus assay. These results indicate that RCK50 has no genotoxic potential under these experimental conditions. Acute oral toxicity studies of RCK50 were carried out in ICR mice of both sexes. RCK50 did not show acute oral toxicities and LD_50 values were over 2.850 ㎎/㎏ in ICR mice.

접합부/철골 커플링 보 강도비에 따른 복합 병렬 전단벽의 내진거동

윤현도,박완신 대한건축학회 2005 大韓建築學會論文集 : 構造系 Vol.21 No.1

Due to lack of information, current design methods to calculate embedment length are tacit about cases In which hybrid wall system has Joint details of stud bolts and horizontal Lies In this study, we set out to develop model for calculating the embedment lengths of embedded steel section in a hybrid wail system, and analytical and experimental studies on steel coupling beam-concrete wall connections were earned. out The cyclic response of steel coupling beams embedded into reinforced concrete boundary elements was studied Three half-scale subassemblies representing a portion of a prototype structure were designed, constructed, and tested The main test variables were the ratios of connection strength to coupling beam strength depending upon embedment length of embedded steel section The Initial stiffness of the coupling beams In all the specimens was smaller than the value computed assuming full fixity at the face of the wall The effective fixed point of steel coupling beams with auxiliary bars inside the wall is about 1/6 to 1/5 of the embedment length