산성강하물이 지표수의 산성화에 미치는 영향 Ⅰ: 현장 조사

김영관,이동석,김만구,우경식 江原大學校 附設 環境硏究所 1997 環境硏究 Vol.14 No.-

Effects of acid deposition on the acidification of surface water over a short period were studied during June~October, 1995. A reservoir located in Chunchon, Kangwondo was selected for this study because this reservoir had received little man-made pollutants. Geological survey within the study area was carried out and the pH of a small and shallow stream flowing from the mountain valley down to the reservoir was monitored. Rainfall was measured by using a rain gauge and the precipitation was collected by automatic precipitation sampler. During the study period, rain pH was in the range of 3.81~5.77 with an average of 4.8. The EC was in the range of 8~189㎲/cm with an average of 10.6㎲/cm. Ionic composition of the rainfall showed that, of the anions, deposition of SO₄^(2-) was highest with 3,119.7 kg/㎢, and is was NH^(4+)with 1,053.2kg/㎢ for cations. The surface water pHs were maintained neutral or weak basic, representing little evidence of acidification regardless of the acidic rainfall pH. Every time of sampling, however, the pHs exhibited increasing tendency as elevation of measuring site of the stream become lowered, which indicated the impacts of acid-base reactions by acidic or basic substances during travel of water downstream. This result suggested the necessity of further research to determine the respective buffering capacity of soil and underlying rocks. 산성강하물이 단기간에 걸쳐 지표수의 산성화에 미치는 영향을 조사하기 위하여 1995년 6월 부터 10월까지 외부오염원이 거의 없는 강원도 춘천시에 위치한 저수지를 선정하여 인구를 수행하였다. 연구지역 일대의 지질을 조사하고 산골짜기에서 저수지로 흐르는 작고 얕은 하천의 수질을 분석하였다. 강우량은 우량계를 이용하여 측정하였고 강하물은 자동포집기를 이용하여 포집하였다. 연구기간동안의 강우의 pH범위는 3.81~5-77로 평균 4.8을 나타내었으며 전기전도도(EC)sms 5~189㎲/cm로 평균 10.6㎲/cm를 나타냈다. 음이온 중에서는 SO₄^(2-)의 강하량이 3,119.7kg/㎢로 가장 많았고, 양이온 중에서는 NH^(4+)가 1,053.2kg/㎢로 가장 많았다. 지표수의 pH는 중성 또는 약염기성으로 강우의 pH가 산성이었음에도 지표수의 산성화 현상은 관찰되지 않았다. 그러나 골짜기에서 흐르는 하천수를 측정할때마다 측정지점의 고도가 낮아질수록 pH값은 증가하는 경향을 나타내어 물이 하류로 흘러가는 동안에 일어난 산성 또는 염기성물질로 인한 산염기반응의 영향을 보여주었다. 이 결과는 토양의 완충능력과 모암내에서의 중화능력을 각각 구별하여 조사할 필요성을 제시하였다.

산성강하물이 지표수의 산성화에 미치는 영향 Ⅱ: 컬럼연구 및 현장조사

김영관,우경식 江原大學校 附設 環境硏究所 1997 環境硏究 Vol.14 No.-

토양층과 모암층에서의 산성우에 대한 중화능력을 평가하기 위하여 인공강우를 이용한 컬럼실험을 실시하였으며 토양을 이루고 있는 모암 특성의 차이에 의한 산성강하물의 환충효과를 비교하기 위하여 연구지역내의 모암의 조성광물에 차이가 있는 두 개의 골짜기를 선정하고 골짜기에 흐르는 지표수의 pH를 1996년 5월부터 1996년 10월까지 측정하였다. 컬럼실험에서 사용한 인공강우는 증류수에 황산과 질산을 적절히 첨가하여 pH를 각각 3,4, 및 5로 조절하였으며 컬럼유출수의 주요 양이온과 음이온을 측정하였다. A층위와 B층위의 양이온 교환용량(CEC)은 각각 9.68 meq/100g과 6.16 meq/100g 이었으며 인공강우의 살포시 컬럼유출수의 pH는 중간층토양에서보다 양이온 교환용량이 큰 표층토양에서 더 크게 나타났다. 컬럼유출수에서의 Ca^(2+), Mg^(2+), Na^(+)의 합이 점차로 감소하여 지속적인 산성우는 토양의 양이온 교환용량을 감소시키는 것으로 나타났다. 현장조사결과에 따르면 골짜기의 하류로 내려옴에 따라 지표수의 pH는 계속 증가하여 하류로 흐르는 과정에서의 완충효과를 나타내었다. 이러한 완충효과는 모암의 조성광물중 kaolinite와 illite이외에도 smectite를 함유하고 있는 골짜기에서 더 크게 나타나는 것이 특징적이었다. 이 결과는 토양층 뿐만 아니라 모암이 산성우의 완충용량을 가지고 있음을 나타내었다. A column study using artificial acid rain was conducted to evaluate the buffering capacities in soil layer and host rock. In an effort to compare the effect of composition of host rock, two valleys of which compositions of host rock are different were chosen within the study area and the pHs of the water flowing in the valleys were measured from May, 1996 to October, 1996. The pHs of the artificial acid rain prepared by adding appropriate amounts of both sulfuric and nitric acids to distilled water were 3,4,and 5, and the column effluents were analyzed for major cations and anions. The cation exchange capacities(CECs) of A Horizon and the B Horizon were 9.68 and 6.16 meq/100g, respectively. Compared to the B Horizon, the pH in the column effluent of A Horizon with larder CEC was higher. The sums of Ca^(2+), Mg^(2+) and Na^(+) in the column effluents gradually decreased, indicating the loss of CEC by acid rain. The field study showed that pHs of the surface water in the valleys increased as the water flows downwards. The magnitude of this buffering capacity was greater for the valley in which smectite in addition to kaolinite and illite was a weathered product of host rocks. This also indicates that host rock as well as soil layer retains the buffering capacity.

무심천의 저서성무척추동물 군집의 생태학적 연구

손영목,변화근,심하식 西原大學校 基礎科學硏究所 1999 基礎科學硏究論叢 Vol.13 No.-

The community structure of benthic macroinvertebrate of Musim stream was investigated from 1997 to 1998. The benthic macroinvertebrate composed of 57 species, 47 genera, 35 families, 15 orders, 7 classes in 5 phyla in the specimens of studied area. Among them, aquatic insects composed of 41 species, 23 families amount to 71.9% of all species. EPHEMEROPTERA, TRICHOPTERA and DIPTERA were dominant in upper region(St. 1∼3) and Limnodrilus socialis, Semisulcospira libertina, Physa acuta, Baetis thermicus, Ecdyonurus kibunensis and Chironomidae sp. 2 were dominant in lower region(St. 4∼7). According to the dominance of benthic marcroinvertbrate, upper region were determined as oligo-saprobic to β-mesosaprobic and lower region as α-mesosaprobic to poly-saprobic. Biological indices presented that the community structure of benthic macroinverterbrates is more stabilized, in upper region than in lower region.

공업계 고등학교에서의 수학교과와 전문교과와의 연계성에 관하여 : 7차 교육과정을 중심으로 Focusing on the 7th mathematics curriculum

宋英武,崔現植 順天大學校 師範大學 附屬 科學敎育硏究所 2002 科學과 敎育 Vol.10 No.-

It seems that it is critical to comprehend mathematics as a tool subject in order to understand a number of calculations in the professional subjects in th Industrial or Vocational Highschool. But, 'Math' subject in the industrial high school has not done very well for the followings; In the industrial high school, 1. So far, professional subjects and 'Mathematics' subject have been carrying out differently. 2. 'Mathematics' subject has been focused on entering the higher academic system, rather college or university as the normal high schools. 3. Industrial highschool students were by far poorer in Math's grades when they were in middle schools than those of the normal high schools. 4. The new 'Math' textbook of 7th educational reform curriculum is not considered in the light of relationship with professional subjects. For these reasons, it seems that a new attempt is necessary to study 'Math' subject while it maintains with relationship with professional subjects. In this study, we do analyze the relationship between professional subjects and 'Math' subject in the Industrial or vocational High school. In the end, we suggest that we should make new 'Math' textbook which reflects the reality and needs of the present Industrial or vocational high school students. In doing so, we hope that Industrial or Vocational high school students can get better grade of Math by identifying learning factors relating with 'Math' in the professional subjects, and that this study can help them learn professional subjects more efficiently.

일제시대의 검도에 대한 의미

김영학,이인희,허건식 龍仁大學校 武道硏究所 1998 武道硏究所誌 Vol.9 No.1

An mentioned above, Korean Kumdo may be considered that Japanese Kendo as a sport has been introduced and popularized here. Some argue that a conservative way of thought due to the principle of Confucianism here interrupted a continuity of Korean Kumdo until the open-door period. But it is high probable that at that time Japanese Kendo has been already introduced and performed here to educate army or police without any difficulty. And it can not dendy that a continuity of Korean traditional Kumdo might be interruped long before the open-door period. A ter the Japanese annexation of Korea. the encouragement of military arts by the political intention of Japan played a remarkable role on the introduction of Japanese Kendo into Korea. and also Kendo was used to maintain public peace and order as a game of national defence, and the common here could not easily contact with Japanese Kendo. That is why then Kendo was started just for the Japanese for the purpose of fostering a Japanese sprit, used as a means to emphasize Japanese Imperial civilians as a colony policy. In the end, it is possible that them many civilians would experience Japanese Imperial civilian gymnastics.

경계요소법에 의한 이종재료 접합 잔류열응력의 해석

유영철,이 원,윤인식,정의섭 韓國非破壞檢査學會 1995 한국비파괴검사학회지 Vol.15 No.4

전자 부품의 일종인 LSI 패키지의 제조 과정에서 절연·방진·방습 등을 목적으로 수지 몰딩이 널리 사용되고 있는데, 냉각과정에서 금속과 수지의 계면에 접합 잔류열응력이 발생하여 파괴의 원인이 되고 있다. 접합 잔류열응력의 측정에는 X선 회절법등이 사용되지만 측정상의 어려움과 계면단 응력특이성에 대한 해석의 곤란함 때문에 적절한 모델링에 따른 수치해석적 연구가 새로이 주목을 받고 있다. 본 연구에서는 Al/Epoxy를 몰딩 접합한 세가지의 대표적인 계면 형상을 선정하여 계면에서의 잔류열응력을 경계요소 수치 해석 및 스트레인 게이지를 이용한 실험을 통하여 각각 해석하였다. 수치해석과 실험결과는 정상적으로 잘 일치하였으며, 서브 요소를 사용하므로써 계면단 응력 특이성의 해석 정밀도를 향상시킬 수 있었다. 또한 접합 잔류열응력의 해석결과로부터 수직응력에 의한 계면 박리가 예상되고, 피착체의 두께가 증가할수록 응력 특이성이 강하게 나타남을 확인하였다. In general residual stress is measured by X-ray diffraction method but in case of bonding residual thermal stress it is inadequate technique to examine the stress singularity. Therefore Two-dimensional elastic boundary element analyses were carried out to investigate the residual thermal stress and stress singularity of bonding interface in Al/Epoxy. This boundary element results were compared with the strain gauge measurements. The effects of different interface models, sub-elements and adherend thickness are presented and discussed. On the basis of the obtained results, interface delamination causing by normal stress is expected and stress singularity is observed more intensively increasing with adherend thickness. It is concluded that the bonding strength of Al/Epoxy interface can be estimated correctly by taking into account the stress singularity at the edge of the interface.

퍼지 제어 이론을 이용한 이동 로봇의 장애물 회피 알고리즘

유영순,가춘식 安東大學校 工業技術硏究所 2000 공업기술연구논문집 Vol.7 No.1

이 논문은 새로운 지연 시간 기법을 도입한 퍼지 논리 제어기를 개발하여 자율 이동 로봇이 미지의 환경에서 고정 및 이동 장애물을 회피하는 알고리즘을 제안한다. 이 논문에서는 실시간으로 임의로 변화하는 장애물 회피 문제를 해결하기 위하여 지연 시간 기법을 이용한 개선된 퍼지 제어 알고리즘을 개발하였다. 이러한 제어 방법은 정해진 목표점을 장애물과 부딪히지 않고 실시간으로 최적의 경로를 찾아 실시간으로 주행하도록 하는데 매우 유용하다. 컴퓨터 모의실험을 통해 장애물 회피에 있어서 제안한 제어기법의 유용성을 검증하였다. This paper presents a delayed time path planning method of the Autonomous Mobile Robot using fuzzy logic controller for avoidance of fixed and moving obstacles in unknown environment. It is the objective of this paper to develop fuzzy control algorithms using delayed time techniques to deal with moving obstacles randomly in real time. This control method gives the benefit of the collision free movement in real time and optimal path to the pre-settled goal. The computer simulations are demonstrated the effective of the suggested control method in obstacle avoidance.

Skemp 이론에 기초한 놀이학습 프로그램이 수학학습능력과 수학적 태도에 미치는 영향

정찬식,정영옥 진주교육대학교 초등교육연구소 2005 科學敎育硏究 Vol.28 No.-

This study aims to facilitate play-activities in 6-Ga stage primary school mathematics curriculum through developing play-activities program based on Skemp's theory and analyzing its effects on mathematics learning abilities and mathematical attitudes of students in the primary school. In order to work out these questions, this study adopted pretest-posttest control group design in quasi-experimental designs. The subjects of study were 68 students attending the J primary school in Jinju city. The newly developed program was applied to the experimental group, while the current mathematics textbook was implemented to the control group. Based on the results of the experiment, the following conclusions were drawn. Firstly, the developed play activities program based on Skemp's theory were consisted of 25 play-activities which can be classified in 4 types of play activity such as concept formation, principle discovery, skill practice and problem solving. Secondly, it proved that the developed play-activities program based on Skemp's theory was more effective to higher level of student than other average and lower level of students. Thirdly, the developed play-activities program based on Skemp's theory was more effective than the one in school now for improving mathematical attitudes. In conclusion, the developed play-activities program based on Skemp's theory has positive effects on improving students' mathematics learning abilities and mathematical attitudes.

放射電磁波에 의한 絶緣診斷에 관한 硏究

김영훈,박원주,이동인,김충년,이광식 嶺南大學校 工業技術硏究所 1995 工業技術硏究所論文集 Vol.23 No.1

In this paper, the detect of insulation disorder and process degree of insulation degradation of power apparatus, the waveform of discharge current, magnitude of discharge and frequency spectrum of the electromagnetic wave radiated from partial discharge by simulating with needle-to-plane electrode geometry and dielectric with artificial void, were investigated. The results obtained can be summarized as follows. 1) Streamer pulses occur near the positive cycle and trichel pulses near the peak of negative cycle of applied voltage. At that time, discharge magnitude of trichel pulses and streamer pulses was observed about 200[pC] and 500[pC] in air, respectively. 2) The level and frequency spectrum of radiated electromagnetic waves were increased about 20∼40[dB] at under 200[MHz] and about 2∼3[dB] above 200[MHz], compared with background noises. 3) A sudden change of discharge magnitute above 20∼30[pC] was observed with various applied voltages, but the magnitude showered to tend to saturate at 300∼300[pC] in dielectric. 4) The level and frequency spectrum of radiated electromagnetic waves were increased about 3∼6[dB] under 200[MHz]and about 2∼3[dB] above 200 [MHz], compared with background noises.

현금흐름정보의 유용성 제고방안

신영식 大邱大學校 社會科學硏究所 1999 社會科學硏究 Vol.6 No.2

자금흐름정보의 제공에 있어서 그 동안 여러차례의 개정을 거듭한 현금기준에 의한 현금흐름표의 타당성이 인정된다. 그러나 현행기준에 의하여 현금흐름표를 작성하는데 몇가지 문제점을 지적할 수 있다. 첫째, 영업할동으로 인한 현금흐름의 계산에 있어서 직접법과 간접법을 자의적으로 선택하게 할 필요가 있는지의 문제이다. 둘째, 영업할동으로 인한 현금흐름을 직접법에 의하여 계산할 때 양식의 표현에 있어서 “매입 및 종업원에 대한 유출액”으로 매입으로 인한 유출액과 종업원에 대한 유출액을 함께 표시하고 있는데 이러한 중요한 사항을 통합하여 표시하는 것이 자칫 양식을 간단하게 하기 위함보다는 오히려 제공되는 정보의 질에 문제가 제기 될 수도 있다. 셋째, 양식의 복잡성을 피하기 위하여 비현금거래를 양식에서 삭제하고 현금의 유출과 유입이 없는 거래 중 중요한 거래를 주석으로 기재하도록 하고 있는데 이러한 비현금 거래를 통합하여 양식에 추가하여 기재할 수는 없는지 등의 문제이다. 이상에서 몇가지를 문제점으로 지적하였으나 이는 어디까지나 제공하는 정보의 질과 양에 관한 상대적인 문제이기 때문에 이에 대하여 좀더 구체적인 연구가 있어야 할 것으로 생각된다.