중금속의 토양 오염: 한국중부지역의 농경지를 중심으로

김기현,김세현,최영천,Kim, Ki-Hyun,Kim, Se-Hyun,Choi, Young-Cheon 대한자원환경지질학회 1996 자원환경지질 Vol.29 No.6

To assess soil distribution patterns of heavy metals in agricultural environments, we have measured the concentrations of six metals from surficial soils of three different groups divided on the basis of the surrounding environment: (1) soil group I-cultivated soils within the purely agricultural regions, (2) soil group II-both cultivated and uncultivated soils near various livelihood facilities, and (3) soil group III-mainly cultivated soils near major polluting sources. The mean concentrations for the three soil groups were found in the range as follows: 0.12~0.15 (Cd), 4.94~6.08 (Pb), 0.05~0.11 (Hg), 2.82~3.50 (Cu), 4.69~7.82 (Zn), and 0.36~0.78 (As) ppm. Examination of data distribution trends indicates that the concentrations determined from the relatively unpolluted soil environs (groups I and II) were comparable not only between each other but also with those reported previously in background soil environs of Korea. The concentration data for the soil group III were however found to be much higher than the rest two groups. Unlike the direct comparison of the magnitudes of concentrations, results of a regression analysis exhibited much different patterns: it was seen that the correlation patterns for soil group I were rather analogous to those of soil group III. The similarities in correlation patterns between groups I and III along with the lack of correlations in soil group II suggest that soil characteristics such as whether being cultivated or not are important factors affecting soil distributions of heavy metals.

한국 황해지역의 DMS 분포특성에 대한 연구 - 덕적도를 중심으로

김기현,김지영,송기범,김나영,이강웅,배귀남,Kim, Ki-Hyun,Kim, Ji-Young,Song, Ki-Bum,Kim, Na-Young,Lee, Gang-Woong,Bae, Gwi-Nam 한국지구과학회 2000 한국지구과학회지 Vol.21 No.1

황해지역에서 생성 및 배출되는 자연황화합물의 규모를 정량적으로 구명하기 위한 노력의 일환으로, 본 연구진은 황해에 위치한 덕적도를 주 측정점으로 설정하고 대기 중에 존재하는 DMS의 농도분포를 1999년 4월과 9월 2차례의 집중측정기간을 통해 측정하였다. 그리고 이에 덧붙여 1999년 6월에는 청도-인천간 해상실험을 통해 황해상의 DMS 농도를 측정하였다. 덕적도를 중심으로 시행한 양 측정기간 중 DMS의 농도값은 4월 측정의 경우 평균과 표준오차가 $24.0{\pm}40.5$ pptv(n=40)인데 반해 9월 측정의 경우 $61.1{\pm}37.9$ pptv(n=35)로 나타났다. 그리고 선상실험에서 측정한 DMS 값은 대체로 배경농도에 가까운 낮은 농도범위를 갖는 것으로 밝혀졌다. DMS의 농도분포는 일반적으로 불규칙한 양상을 보였지만, 주변 기상인자의 변화경향과 유사하게 변화하는 것으로 나타났다. 본문에서는 이러한 연구결과와 기존의 연구결과 등을 연계하여 잠정적인 연간 배출량규모를 4Gg 대로 추정하였다. 이러한 배출규모는 과거 제주지역 등을 중심으로 측정한 결과에 비해 상대적으로 낮은 수치인데, 시간적 및 공간적으로 대표성이 강한 보다 객관적인 배출량을 산정하기 위해서는 추가적인 측정 자료의 축적이 요구된다. This study was performed to accumulate database for natural sulfur emissions in the Yellow Sea region of Korea. The atmospheric concentrations of dimethylsulfide(DMS) were measured during two intensive field experiments (April and September 1999) from Duk-Juk Island located in the Yellow Sea. Ship-measurement of DMS was made additionally between Chungdo(China) and Inchun(Korea) across the Yellow Sea during June 1999. The mean(and ISD) of DMS concentrations in Duk-Juk Island during two field campaigns was $24.0{\pm}40.5$(n=40, April) and $61.1{\pm}37.9$ pptv(n=35, September), respectively. The atmospheric DMS measured from ship experiments was generally low and close to the background concentrations in the open sea area. The temporal distributions of DMS concentration were complicated in some sense but comparable to those of ambient meteorological parameters. On the basis of our measurements of atmospheric DMS(and evidence found from previous studies), the sea-to-air flux of DMS in the Yellow Sea is estimated to be about 4Gg S/yr. This amount of natural S emissions is relatively lower than the estimates derived for Cheju Island. Therefore, additional experiments may be desperate to derive more reliable figures for natural sulfur emissions in the Yellow Sea region.

유문사친(儒門事親)에 나타난 소아(小兒)와 관련된 이론(理論)과 치법(治法)에 대한 고찰(考察)

김기현,장규태,김장현,정우병,Kim, Ki-Hyun,Chang, Gyu-Tae,Kim, Jang-Hyun,Jung, Wu-Byung 대한한방소아과학회 2005 대한한방소아과학회지 Vol.19 No.2

Objective : Rumenshiqin(儒門事親) was compiled by Zhang Zi Huo(張子和) of the Jin(金) Dynasty of China. He invented unique medical theory and treatment such as three excretive methods(perspiratory, vomitory and purgative therapy). The aim of this study was to make the best use of the therapeutic theory of Rumenshiqin(儒門事親) connected with pediatrics. Methods: We conducted literature search in detail for contents of Rumenshiqin(儒門事親) and reviewed various kinds of books. Results : Zhang Zi Huo(張子和) recognized that children had pure-yang bodies(純陽之體) and emphasized that children need to prevent heat-stagnation(鬱熱) and asthenic yin(損陰). He instructed that a principle of raising such as wearing thin clothes, eating fresh food, harboring little desire and little anger, and taking temperate medicine. He described that pathogenic factors were mistake of rearing, misuse of medicine, exogenous factor, and excessive emotion. Conclusion : According to the above results, it is concluded that his therapeutic theory should be used at present.

임신돈 사료 내 만삼추출분말의 첨가 급여가 모돈과 자돈의 생산성 및 면역력에 미치는 영향

김기현,김광식,김조은,정현정,이성대,사수진,홍준기,허태영,박준철,김영화,Kim, Ki-Hyun,Kim, Kwang-Sik,Kim, Jo-Eun,Jung, Hyun-Jung,Lee, Sung-Dae,Sa, Soo-Jin,Hong, Joon-Ki,Hur, Tai-Young,Park, Jun-Cheol,Kim, Young-Hwa 한국유기농업학회 2013 韓國有機農業學會誌 Vol.21 No.3

본 연구는 만삼추출분말의 모돈 사료 내 첨가급여가 모돈 및 자돈에 있어서 면역력과 생산성에 미치는 영향을 조사하기 위하여 실시하였다. 20두의 F1 임신돈(Landrace ${\times}$ Yorkshire)을 옥수수와 대두박을 기초로 하는 임신돈 기초사료 급여구와 만삼추출분말 0.5% 첨가 급여구로 나누어 각각 10두씩 배치하여 공시동물로 이용하였다. 실험사료를 분만예정일 40일 전부터 분만 후 이유 시(25일)까지 급여하였다. 만삼은 항산화 효과와 더불어 면역증강 효과가 있는 것으로 알려져 있어, 모돈 사료 내 만삼추출분말의 급여는 모돈의 면역능력을 증강시켜 결과적으로 자돈의 면역력 상승효과를 가져올 것으로 예상하였다. 또한 면역력 상승에 따른 보상효과로 자돈의 생산성 및 성장 촉진을 기대하였다. 본 연구의 결과에서는 만삼추출분말의 첨가급여가 모돈 및 자돈에 있어서 면역력과 생산성에 영향을 미치지 않는 것으로 나타났다. 초유 내 IgG 함량과 자돈 혈액 내 IgG 함량 사이의 상관관계는 유의적이지는 않았지만, 양의 상관관계(correlation coefficient, 0.435 P=0.102)를 나타내어, 초유 내면역력의 상승은 자돈에 이로운 영향을 미칠 수 있음을 시사하였다. 이상의 결과로부터, 면역항진 기능을 가진 만삼추출분말의 생리활성 물질은 임신 모돈의 생체 내에서 충분한 면역촉진효과를 나타내지 않은 것으로 사료된다. 따라서, 면역증강제로써 임신돈 사료 내 만삼추출분말의 이용 가능성을 평가하기 위해서는, 만삼추출분말 내 생리활성 물질의 생체내 대사 메커니즘과 작용기전을 검토할 필요가 있는 것으로 판단된다. The Codonopsis pilosula is traditional oriental herb associated with immune-modulatory functions and has anti-inflammatory properties and antioxidative activity. The present study was conducted to investigate the effects of dietary supplementation of Codonopsis pilosula extract powder (CEP) on the immunity and productivity in sows and piglets. A total of 20 pregnant sows were randomly assigned to two dietary treatments, which was given a corn-soybean meal diet with 0% and 0.5% CEP from 40 days prepartum to weaning (25 days postpartum). The immune system of piglets was expected to build up, because the feeding of CEP might increase the colostrum contents in sows. We also predicted that the growth performance of piglets also could be increased by some compensation effects due to the increased immunity of piglets. In results, immunities of sows and piglets as well as growth performance of piglets were not affected by the supplementation of CEP. The correlation between the colostrum and the serum on the IgG contents tended to have a positive correlation, although there was no significant (coefficient, 0.435; P=0.102). This result suggests that the supplementation of CEP may increase IgG contents in sows and piglets and contribute to improve immunity of piglets. In conclusion, it is thought that the physiologically active substances of CEP did not influence to the immune synergic effects in vivo of sows. Thus, the metabolic and action mechanism of the physiologically active substances of CEP should be explored to evaluate the availability of CEP as a feed additive for the immunomodulator.

귀비탕가감방(歸脾湯加減方)이 구속 Stress 유발 백서(白鼠)에 미치는 영향

김기현,장규태,김장현,권혁란,Kim, Ki-Hyun,Chang, Gyu-Tae,Kim, Jang-Hyun,Kwon, Hyuk-Ran 대한한방소아과학회 2005 대한한방소아과학회지 Vol.19 No.2

Objectives: This study was aimed to find out the anti-stress and protective-memory effect of Quibitanggagam(QBT) on stress of rats Methods : This experimental study was conducted with elevated plus maze test, passive avoidance test, morris water maze test, and consequently density of AchE reactivity in the CA1 of hippocampus to research the learning and memory of rats affected by restraint stress, Results: Passive avoidance test revealed that time latency of retention test for QBT+Stress group significantly decreased on 2, 3rd day. Morris water maze revealed that acqusitive ability of QBT+Stress group significantly improved on 2, 3rd day and retentive ability of QBT+Stress group was significantly improved on 7th day. Elevated plus maze test revealed that latency in open arm of QBT+Stress group significantly decreased and locomotor activity(number of entered arm) of QBT+Stress group was significantly increased. The values of density of AchE stained nuclei in the CA1 of hippocampus QBT+Stress group was significantly increased compared with SAL+Stress group. Conclusion : According to the above results, it is concluded that QBT will be useful as a remedy against stress disease and improving memory.

서울시 한남동과 경기도 과천시 지역을 중심으로 한 대기 중 수은의 분포특성 연구

김기현,김민영,Kim, Ki-Hyun,Kim, Min-Young 한국지구과학회 2001 韓國地球科學會誌 Vol.22 No.3

1999년 9월부터 2000년 7월까지 서울시 한남동과 경기도 과천시 두 지역을 중심으로 대기 중 수은의 농도를 시간대별로 관측하였다. 두 지역의 여러 가지 여건 차이에도 불구하고, 양 지역의 농도는 각각 5.34(N=2576), 5.25ngm$^{-3}$(N=1992)를 기록하였다. 본 자료를 이용하여 양 지역의 농도 분포 특성을 비교하였다. 24시간 주기로 볼 때, 한남동 지역은 야간대에 그리고 과천 지역은 주간대에 높은 강도를 띠는 것으로 나타났다. 계절적으로는 한남동 지역에서 겨울 그리고 과천 지역에서는 여름에 최고농도를 기록하였다. 양 지역에서 수은의 농도를 조절하는 요인을 여러 가지 통계적 기법으로 고찰하였다. 본연구의 결과에 의하면, 연구 지역의 대기중의 수은 분포는 지역적 발생원의 차이에 의해 크게 영향을 받는 것으로 나타났다. The concentration of gaseous mercury (Hg) was measured at hourly intervals along with relevant environmental parameters from two monitoring stations (Hannam and Kwachun) in Seoul metropolitan city during September 1999 to July 2000. Irrespective of the environmental and areal differences in the two locations, the concentrations of observed Hg levels were remarkably compatible each other. The results showed that the mean Hg level in Hannam was measured to be 5.34${\pm}$3.92 ngm$^{-3}$ (N = 2576), while that of Kwachun was 5.25${\pm}$2.53 ngm$^{-3}$ (N = 1992). Using these measurement data, we inspected Hg distribution and behavior at various time scale. When the data were analyzed at 24 hr scale, the distribution patterns for the two areas were distinguished by enrichment in either night(Hannam) or day (Kwachun). The patterns for seasonal distributions were also opposing each other such as the occurrences of peak during winter (Hannam) or summer (Kwachun). In order to analyze the factors affecting Hg distributions between two sites over different time scale, we conducted both correlation and factor analysis on both all data sets and on seasonally divided data groups. Whereas Hg exhibits strong correlations with such parameters as PM (particulate matter), SO$_2$, and NO$_2$, its relationship with meteorological parameters was not significant enough in many cases. The results of factor analysis also indicated that the Hg levels are tightly associated with most pollutants, explaining the largest portions of statistical variance. According to our study, we conclude that patterns of Hg distributions can exhibit variable patterns depending on local source processes which we expect to be diverse among different areas.

급속승온공정을 이용한 사출성헝된 Fe 소결체의 미세조직 및 소결거동

김기현,한재길,유지훈,최철진,이병택,Kim Ki-Hyun,Han Jae-Kil,Yu Ji-Hun,Choi Chul-Jin,Lee Byong-Taek 한국분말야금학회 2004 한국분말재료학회지 (KPMI) Vol.11 No.6

Using the nano Fe powders having 50 nm in diameter, Fe compact bodies were fabricated by injec-tion molding process. The relationship between microstructure and material properties depending on the volume ratio of powder/binder and sintering temperature were characterized by SEM, TEM techniques. In the compact body with the volume percentage ratio of 45(Fe powder) : 55(binder), which was sintered at $700^{\circ}C,$ the relative density was about $97{\%},$ and the values of volume shrinkage and hardness were about $66.3{\%}$ and 242.0 Hv, respec-tively. Using the composition of 50(Fe powder) : 50(binder) and sintered at $700^{\circ}C,$ the values of relative density, volume shrinkage and hardness of Fe sintered bodies were $73.3{\%},\;47.6{\%}$ and 152.8 Hv, respectively. They showed brittle fracture mode due to the porous and fine microstructure.

2,3차원배열을 갖는 섬유상 A1₂O₃-(m-ZrO₂)/t-ZrO₂ 복합재료의 제조

김기현,이병택,Kim Ki-Hyun,Lee Byong-Taek 한국재료학회 2005 한국재료학회지 Vol.15 No.9

Microstructure and mechanical properties of fibrous $A1_2O_3-(m-ZrO_2)/t-ZrO_2$ composite were investigated depending on the dimensional array. By the change of stacking arrangement of fibrous filaments, 2 and 3-dimensional fibrous composites were successfully obtained without bulk defects such as shrinkage cavity and cracks. The maximum mechanical properties were achieved In the 3-dimensional array composite, due to the fine fibrous and dense microstructure control, in which the values of vickers hardness, fracture toughness and bending strength were about 1507 Hv, $7.2MPa{\cdot}m^{1/2}$ and 650 MPa, respectively.

협동학습의 적용 사례 연구

김기현,Kim Ki-Hyun 한국공학교육학회 2002 공학교육연구 Vol.5 No.2

협동학습의 목적은 경쟁보다는 협동을 통하여 학습 효과를 높이고 아울러 전공외적 소양으로 가장 중요시되는 teamwork과 의사 친달 능력을 기르는 데 있다. 이 논문은 아주대학교 기계공학 전공의 유체역학 과목에서 시행한 협동학습의 진행 과정과 결과에 대해 기술한 것이다. 학생들을 대상으로 설문 조사를 한 결과 협동학습에 대한 학생들의 반응이 대단히 긍정적인 것임을 확인할 수 있었으며 소기의 목적을 충분히 달성한 것으로 판단된다. 몇 가지 개선할 점도 있으나 협동학습은 그 결과에 대한 우려 없이 시행하여도 될 교수 방법으로서 권장할만한 교수법이라고 생각된다. Cooperative learning is known as an innovative and effective teaching method in enhancing student learning and, at the same time, in improving their teamwork and communication skills. The author utilized cooperative learning strategies in teaching fluid mechanics at Ajou University and this paper describes and discusses the methods adopted and the associated results. The results of a survey conducted at the end of semester are presented and some suggestions are made for further improvement.

나노 Fe 분말을 이용하여 사출 성형된 Fe 소결체의 제조

김기현,임재균,최철진,이병택,Kim Ki-Hyun,Lim Jae-Hyun,Choi Chul-Jin,Lee Byong-Taek 한국재료학회 2004 한국재료학회지 Vol.14 No.11

The injection molded Fe sintered bodies were fabricated using two kinds of Fe powders haying 50 nm and $3\sim5{\mu}m$ in diameter. In the using of Fe powder having 50 nm in diameter, the comparatively dense bodies ($94\sim97\%$) were obtained even at low sintering temperature ($600\sim700^{\circ}C$), while in the sintered bodies ($1000^{\circ}C$) using $3\sim5{\mu}m$ Fe powder, their relative densities showed low values about $93\%$, although they were strongly depend on the sintering temperature and volume ratio of Fe powder and binder. In the sintered bodies using of 50 nm Fe powders, the volume shrinkage and grain size increased as the sintering temperature increased, but the values of hardness decreased. In the sample sintered at $650^{\circ}C$, the values of relative density, volume shrinkage and grain size were $96\%,\;37\%\;and\;0.97{\mu}n$, respectively and the minimum value of wear depth was obtained due to combination of fine grain and comparatively high density.