금속-산화막-반도체 소자의 계면전하 발생에 미치는 정공과 수소의 역할

노용한 成均館大學校 科學技術硏究所 1996 論文集 Vol.47 No.2

MOS 소자의 게이트산화막에 정공이 트랩핑된 후 계면전하의 발생 메커니즘을 게이트 금속의 종류 및 게이트 인가된 전압의 극성의 함수로써 연구하였다. 기존의 정공 트랩핑에 의한 계면전하의 발생 메커니즘과는 다른 새로운 메커니즘을 확인하였으며, 트랩핑된 정공과 발생된 계면전하의 상관관계는 16 : 1이였다. 본 연구 결과와 기존의 모델들을 토대로 고열전자에 의하여 MOS 소자의 발생하는 계면전하의 발생 메커니즘을 전하와 수소의 역할을 구분할 수 있는 전자주입 fluence의 함수로서 규명하였다. Mechanisms of interface traps induced by hole trapping was investigated as a function of both gate metals and gate polarity applied during the stressing. We find that a new generation mechanism which has not been reported previously, and show that approximately one interface trap is induced by sixteen trapped holes. Based on the current findings, we propose a comprehensive interface-trap generation mechanism which can predict the hot electron effects so that clarify the roles of hydrogen and trapped holes as a function of injection fluences.

영광 원자력발전소 3,4호기의 계통 병입에 따른 전력계통의 안정도 해석

박철원,권명현,김철환,신명철 成均館大學校 科學技術硏究所 1994 論文集 Vol.45 No.2

This paper deals with consideration for transient stability of power system The analysis of transient stability is very important because it detects the possibility of large scale outage by system collapse caused system configuration change and load unbalance. Two units YGN 3&4 will be connected to the YGN 1 & 2 switchyard through two 345KV circuits until 1996 because of the nuclear power plant construction according to power demand increment. Therefore it is necessary to study stability analysis, fault capacity calculation and power flow problem in assumption of two units YGN 3&4 operation interconnected with the power system Finally, considerations of the effect of interconnection and the establishment of preservation methods for reliability of stable opration of the power system are included in this paper.

Ni_3Al 金屬間 化合物의 高溫酸化時 酸化膜의 剝離에 關한 硏究

崔松天,李東馥 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

The high temperature oxidation behavior of the intermetallic compound of pure Ni_3Al was studied above 1000℃. In isothermal oxidation tests between 1000-1200℃, Ni_3Al showed parabolic oxidation behavior and displayed excellent oxidation resistance. In cyclic oxidation test, Ni_3Al exhibited excellent oxidation resistance but the drastic spalling of oxide scales was observed at 1300℃. Al_2O_3 was present as θ-Al_2O_3 in a whisker form at 1000℃, but, as the temperature increases, thermodynamically metastable θ-Al_2O_3 was transformed to stable α-Al_2O_3. At 1200℃, α-Al_2O_3 having an equiaxed structure in the outermost scale and columnar structure inside was present. Scale spalling it Ni_3Al was attributed to the kirkendall voids formed at the metal/oxide interface, which act as the source of stress concentration.

Benzene의 감압증류시 응축기 용량과 회수율과의 경제성 연구

김태환,이경주,이대광,원성호,김남기 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

In order to achieve economic solvent recovery, the recovery ratio was tested on the vacuum distillation of benzene as a solvent by changing the condenser capacity. The results obtained in this experiment were as follows; 1) As increasing the condenser capacity by 6.4 times from 35㎠ to 225㎠, solving recovery ratios were increased by 20%, 24%, and 31% at the bath temperature of 30℃, 40℃, and 50℃ respectively. 2) It was more effective for the solvent recovery ratio to use 10℃ coolant instead of 20℃ coolant, the differences of recovery ratios were about 28%∼32%. The differences of solvent recovery ratios used 0℃ coolant were about 33%∼44% and those used -10℃ coolant were 38.7%∼49%. 3) Bath temperature and solvent recovery ratio are closely related to the condenser capacity. In the case of small condenser capacity, the recovery ratio was increased at low bath temperature. On the other hand, in larger condenser capacity, the recovery ratio was increased at the high bath temperature. From the results of this study we found that the condenser capacity of 55㎡ was the optimal condition for the economic recovery of benzene.

우리나라 主要農産物輸入構造變化分析

鄭炳瑞 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

This study tests the hypothesis that institutional changes in Korea caused structural changes in its import demand for major grains. It used a single equation system approach to estimate Korea's major grain import demand. A chow test method was used to identify structural changes from 1973 to 1991. No significant structural shifts were found to have been caused by instituional changes in the 1970s and 1980s.

미국 및 캐나다 地域에서 栽培, 販賣되고 있는 무궁화 品種에 關한 硏究

沈慶久,河有美,朴永洙,金健澔 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

This sutdy was carried out to examine the present distribution and status of Hibiscus cultivars by analyzing the US and Canadian market. The obtained results are summerized as follow : 1. At present, a total of 28 cultivars of Hibiscus are on the market. Among these, twenty four are diploids and four are triploids. The hottest cultivars in the market is a triploid `Diana' sold by 21 different companies. It is followed by 'Ardens' and 'Jeanne d'Arc', following `Red Heart', `Blue Bird', 'Woodbridg e', and 'Helene'. 2. As a conservation or display purpose, several cultivars are ketp in three different arboretums in the US. These include 5 cultivars, `Blue Bird', `Celestial Blue', `Collie Mullens', 'Lucy', and `Ruber Plena', in Arnold Arboretum, and one each, 'Variegatus', at the USDA national arboretum and, `Banner' at Morton arboretum in Chicago. 3. The avarage price for triploid cultivars is $6.00 for each seedling. The recently developed cultivars like 'Helene' and 'Minerva' cost $16.00 per seedling possibly due to their plant patent right. Other cultivars produced by cuttings cost $2.00 to $ 3.00 per seedling. 4. In Canada, there are nine cultivars on the market; being diploids and one triploid, `Diana'. 5. As for the distribution of different cultivars by climatic zone, twelve cultivars are being grown in temperate area like Ohio and Iowa. However, many other cultivars are being cultivated in wamer Southern state like Galifornia. Five cultivars are reported to grow in the relatively cool area like Wisconsin and Minnesota. Even in cold area like Canada, 5 cultivars such as `Anemonaeflorus'(2n), `Ardens'(2n), 'Jeanne d'Arc'(2n), and `Luky'(2n), and 'Paeoniflorus'(2n) at Ontario and there is colder than Hamkyung Do in north Korea.

직교함수를 이용한 이산 시스템의 모델 축소에 관한 연구

안두수,김윤상,김민형,안비오,이재춘 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

In this paper, A method on model reduction of discrete systems via otthogonal functions is presented. The low order systems obtained by this proposed method preserves not only the stability but also the dynamic characteristics of the high order systems. From examples, we can see the reduced model by this method approximates the dynamic characteristics of high order model satisfactorily with respect to various inputs.

Bifidobacterium angulatum으로부터 α-galactosidase의 정제 및 특성

강대중,민해기,강국희 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

α-galactosidase는 (α-D-galactoside galactohydrolase: EC 3.2.1.22)는 다당류나 올리고당인 melibiose, raffinose, stachyose와 guar gum 등의 α-galactosidic 결합을 하고 있는 당을 분해하는 효소이다. 장내세균중 우익균이며 우세균주인 Bifidobacteria로부터 α-galactosidase의 효소학적 특성을 알아보기 위하여 배양여액으로부터 ammonium sulfate분획, 핵산의 제거, Sephadex G-200 gel filtration 및 DEAE-Sephadex A-50 ion exchange chromatography 등의 4단계 정제과정을 거쳐 정제한 결과 약 8배로 정제되어 단일 단백질로 분리하였다. 또한, 효소분해산물을 알아보기 위하여 TLC에 의하여 당분해 및 올리고당의 생성을 알아보았다. 정제효소의 활성 최적온도는 37℃, 최적 pH는 7.0이었다. 효소활성이 K^+, Zn^2+과 같은 금속이온과 8-Hydroxyquinoline, Sodium Bisulfite 등에 의해선 그다지 저해되지 않았으나, Hg^+, Cu^2+과 p-Chloromercuribenzoic acid에 의해선 저해되었다. 효소의 분자량이 301, 995, 합성기질인 PNPG에 대한 K_m은 0.069mM, V_max는 347.22μmol/min.mg protein이었다. To elucidate enzymatic properties of α-galactosidase (EC 3.2.1.22) from Bif.angulatum. α-galactosidase was purified to homogeneity by ammonium sulfate fractionation, protamine sulfate precipitation, sephadex G-200 gel filtration, and DEAE-sephadex A-50 ion exchange chromatography. The purified α-galactosidase was found tobbe homogeneous by SDSpolyacrylamide gel electrophoresis. The molecular weight of this enzyme, estimated by sepadex G-200 gel filtration, was about 301,995. The optimum conditions for the enzyme reaction was pH 6.5 to 7.0 at 37℃. The purified enzyme was stable at 45℃ or below and in buffer at pH 6 to 7.0. The activity was inhibited by mercury, copper ion, and p-chloromercuribenzoic acid. The kinetics of this enzyme, with p-nitrophenyl-α-D-galactoside as substrate, was determined : K_m was about 0.069mM and V_mas was 347.22 μmoles/min mg protein.

原乳의 細菌數에 의한 등급제 실시에 따른 乳質改善 효과

鄭忠一,姜國熙 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

Bulk tank milk of 34 dairy farms in Pochun area, Kyunggido was tested to investigate how much the sanitary quality of raw milk could be improved. The results obtained were summarized as follows : 1. SPC of bulk tank milk of 34 dairy farms was greatly decreased from 85.7% to 18.9% in SPC above 2.1 X 10 exp (5) through an extension service of dairy farming technics and sanitary conditions. 2. The sanitary conditions of cluster and pail of milking machine, a source of bacterial contamination, were also greatly improved. Approximately 80% of the samples showed less than 100/ml in phychrotrophic bacterial count.

컴플라이언스法을 利用한 疲勞龜裂發生의 監視 System에 關한 硏究

崔鎔湜,石昌星,林昌鉉 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

To predict the service life of many steel structures, an understanding of fatigue crack initiation in steel is required. In this paper, the monitoring system of a fatigue crack initiation by compliance technique was described and the fatigue crack initiation life by the system was compared by an ultrasonic technique. The fatigue crack initiation life of a notched specimen in SPS 5A steel was also investigated by the system.