본 연구에서는 하천유역에서 소수력 개발 대상지점에서의 최적규모를 결정하는 방안을 제시하였다. 제시된 방안은 지형 및 수문자료의 구축, 발전소 모의운영, 경제성분석, 최적규모 결정과 같은 일련의 절차로 이루어진다. 최적규모 결정을 위해 경제성 평가지표 가운데 하나인 순현가를 이용하였고, 이를 통해 최적 설계유량과 시설물의 최적규모를 도출하였다. 초기비용의 산출을 위하여 기존 소수력발전소의 비용 자료를 검토하여 함수식을 개발하였고, 편익 산정시 현재 공시된

소수력은 신재생에너지 중에서도 온실가스 배출량이 가장 적은 청정에너지중의 하나이며, 국내 부존량이 매우 풍부하기 때문에 최근 개발에 대한 필요성이 부각되고 있다. 그러나 국내에서 소수력 개발을 위한 자원조사나 연구는 1990년대 이후 매우 미흡한 상황이어서 체계적인 연구가 뒷받침 되어야 할 것이다. 본 연구의 목적은 소수력 개발의 계획단계에서 입지분석을 위한 방법론을 제시하는 것이다. 이를 위해서 제약기준과 입지기준을 설정하고 가중치를 부여하였으며, 각

본 논문은 초등학교 학생들의 소수 개념 이해 실태를 분석하고자 초등학교 4, 5, 6학년 학생들을 대상으로 소수 개념 이해 검사를 실시하였다. 소수 크기 비교 검사를 통해 소수 크기 비교에서 나타나는 학생들의 사고 유형을 분류하여 학생들이 소수를 어떻게 이해하고 있는지 살펴보고, 소수 개념 요소를 측정수, 십진분수, 십진기수법으로 보고 각각의 개념 요소별 이해도를 알아보았다. 3차 분류를 통해 학생들의 다양한 사고 유형을 발견할 수 있었으며, 개념 요소별 이해도가 낮음을 알 수 있었으며 학년별로 큰 차이를 보이지 않음을 지적할 수 있었다. 따라서 소수 개념에 대한 다양한 접근을 통해 소수 개념 학습을 강조할 필요가 있음을 시사해 준다.

On the basis of theory of Bratsch's electronegativity equalization, the electronegativity equalization, the group electronegativities and the group partial charges for cationic and amphoteric surfactants could be calculated using Pauling's electronegativity parameters. From calculated output, we have investigated relationships between CMC(critical micelle concentration) and partial charge and group electronegativity of hydrophilic and hydrophobic groups, structural stability of micelle for cationic and amphoteric surfactants. As a result, CMC depends upon partial charge and electronegativity of hydrophilic and hydrophobic groups for surfactants. In case of cationic surfactant, as the increment of carbon number in hydrophilic group, partial charge of hydrophilic group is increased, but CMC and electronegativity of hydrophilic group is decreased. With increasing the carbon number of hydrophilic group for cationic surfactant, its partial charge is increased, but CMC and its electronegativity are decreased. With increasing the carbon number of hydrophobic group for cationic and amphoteric surfactant, its partial charge is increased, but CMC and its electronegativity are decreased

This study was performed to determine the optimum coagulant dosing for effective treatment of raw water in Chinyang lake. Removal rates of algae and characteristics of the water according to coagulants dosage were investigated by treatment with Microcystis aeruginosa, which is a kind of blue-green algae, to the raw water below 5NTU. The coagulants dosage for maximum removal rate of algae were 30 ㎎/ℓ of Alum, 30 ㎎/ℓ of PAC and 10 ㎎/ℓ of PACS, respectively. The removal rate of algae in 30 ㎎/ℓ of PAC was highest as 85% compared with the other treatments. At the point of maximum removal rate of algae, the removal rates of turbidity were 34%, 66% and 22% in Alum, PAC and PACS, respectively. Residual Al was decreased depend upon decreasing turbidity in water by treatment of Alum or PAC, but decreased depend upon increasing turbidity in water by treatment of PACS. The removal rate of Mn2+ in water was high in the order of Alum, PAC and PACS treatment. And Fe2+ in water was not changed by treatment of these coagulants. Particle numbers distributions according to the particle size of suspended solids that were not precipitated at 8 min. of settling time after treatment of coagulants dosage for the maximum removal rate of algae were investigated. Most of the particle sizes were below 30 ㎛ and particle numbers distributions below 10 ㎛ were 64%, 56% and 66% by treatment of Alum, PAC and PACS, respectively. Zeta potential was in the range of -6.1∼-9.7 mV at optimum coagulants dosage for algae removal.

This study was performed to determine the optimum coagulant dosing amount for effective treatment of raw water. The removal rate of turbidity and the variations of water qualities according to various dosage of coagulants such as Alum, PAC and PACS were investigated. The optimum coagulant dosing amount to make the lowest turbidity of water were 35㎎/ℓ of Alum, 30㎎/ℓ of PAC and l0㎎/ℓ of PACS in case of 5 NTU of raw water turbidity, and 30㎎/ℓ of Alum, 25㎎/ℓ of PAC and l0㎎/ℓ of PACS in case of 10 NTU of that, respectively. The removal rates of turbidity at 4 min. and 8 min. of settling time were 10 and 72% of Alum, 44 and 62% of PAC and 25 and 55% of PACS in case of 5 NTU, and 52 and 70% of Alum, 90 and 95% of PAC and 10 and 28% of PACS in case of 10 NTU, respectively. Judging from the settling capability of floc., the reaction time of floc. formation and removal efficiency of turbidity, PAC was evaluated as more effective coagulant than Alum and PACS. Also PAC was regarded as the most effective coagulant when the water supply was changed sharply and the fluctuation of the surface loading occured with wide and sharp in seettling basin. pH and alkalinity of the water were decreased with increasing coagulants dosage. But pH and alkalinity were not decreased below 5.8 which is the standard for drinking water quality, and l0㎎/ℓ which is the limit concentration of floc. breakage, respectively. Residual Al of the treated water was decreased with increasing coagulants dosage in case of 5 and 10NTU of raw water turbidity. KMnO_4 consumption of the water was decreased with increasing coagulants dosage. The reduction rate of KMnO_4 consumption at the optimum coagulants dosage were 39% of Alum, 18% of PAC and 11% of PACS in case of 5 NTU of raw water turbidity, and 42% of Alum, 27% of PAC and 36% of PACS in case of 10 NTU of that, respectively. Any relationship was not found between the removal rate of turbidity and KMnO_4 consumption. TOC of the water was a bit decreased with increasing coagulants dosage up to 30㎎/ℓ but not changed above 30㎎/ℓ of coagulants dosage. The degree of TOC reduction was increased in the order of Alum, PAC and PACS treatment. Zeta potential of the colloidal floc. at the optimum coagulants dosage was in the range of -20∼-15mV in case of 5 NTU of raw water turbidity and 0∼0.5mV in case of 10 NTU of that, respectively. Although the kinds and dosages of coagulants were different, zeta potential range were fixed under the conditions of the best coagulation efficiency.

This study aims at suggesting a concepturla model of personnel elitism, and at evaluating the model based on a shipping company case. Specifically, it asks whether the company has met the conditions nessary for the attainment of personnel litism prescribed by the conceptural model. In order to evalutate the model, questionnaire and interview methods were adopted. The area of survey includes the quality of personnel , the efficiency level of work processes. and the level of work load. This study concludes that the rationalization of work processes and training and development of personnel are necessary for a company to realize personnel elitism.

This paper discussed effect of the surface roughness and the hydrophobicity of support material on the microbial attachment in a rotating biological contactor. The hydrophobicity of each support material was determined by the measurement of contact angle of water and the surface roughness was measured by the surface roughness instrument. Microorganisms have well attached on the surface of more hydrophilic support material like Nylon6 than that of the hydrophobic support material like PE. When the relatively hydrophilic surface was roughen, the microbial attachment was increased but when the relatively hydrophobic surface was roughen, the attachment was slightly increased because the hydrophobicity of support material was increased by roughening the hydrophobic surface. Although both variables, the surface hydrophobicity and the surface roughness, have influenced the microbial attachment, the influence of the surface roughness overruled that of the surface hydrophobicity. Support material whose surfaces were roughened about l㎛, 6㎛ and 11㎛ were allowed for attached 3, 7 and 24hr, but the differences of maximum and minimum attachment of each material gave nearly constant values and similar trend with time.

쌀보리의 이삭에 관한 기초자료를 얻고자 우리나라에서 육성한 쌀보리의 품종을 공시하여 소수위치에 따른 망의 길이와 무게, 입중 등을 조사한 바 그 결과를 요약하면 다음과 같다. 1. 이삭의 정단부로부터 3∼5번째 소수가 망장 및 망중의 평균치와, 2∼4번째 소수가 입중의 평균치와 각각 일치하였다. 2. 이삭의 기부로부터 3∼4번째 소수의 망이 가장 길고 무거웠으며 5∼6번째 소수의 입중이 가장 무거웠다. 3. 측열 소수는 중앙열 소수에 비하여 망장은 13∼26%, 망중은 26∼41%, 입중은 18∼25% 적은 값을 보였다. nami형 품종은 uzu형 품종에 비하여 중앙열과 측열간 망장, 망중 차이가 적었다. 4. 망중/망장 비로 볼 때 uzu형 품종은 nami형 품종보다, 그리고 중앙열은 측열보다 망이 더 굵었다. 5. 이삭을 3등분하였을 때 망장, 망중은 하부와 중앙부 차이가 없었으나 상부보다는 길고 무거웠다. 입중은 상부가 항상 가벼웠고 중앙부는 하부보다 무겁거나 같았다. 6. 망중이 무거운 소술일수록 입중이 무거웠다.

Because of varied functions and characteristics, water soluble polymers have long attracted much intrest in both academic and industrial fields, especially now in pollution problems such as wastewater treatment through ploymeric flocculants. In this regard, the main objective of this study is to synthesize polymeric floccuants containning hydrophobic group in presence of the potassium persulfate/sodium thiosulfate redox system and to estimate their flocculating ability on the kaolin suspension. In order to test the flocculating power of flocculant prepared on the kaolin suspension system, turbidity of the supernatant liquid, residence time, filtration rate of flocculated samples, have additionally been measured from the flocculation experiments and analysed in comparision with the theoretical background.