• Nuclear Engineering and Technology
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• 제55권1호
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• pp.71-79
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• 2023

Air ingress incidents are major safety accidents in very-high-temperature reactors (VHTRs). Air containing a high volume fraction of oxygen may cause severe oxidation of core components at the VHTR, especially for the significantly thin alloy tube wall in the intermediate heat exchanger (IHE). The research objects of this study are Inconel 617 and Incoloy 800H, two candidate alloys for IHE in VHTR. The air ingress accident scenario is simulated with high-temperature air flow at 950 ℃. A continuous oxide scale was formed on the surfaces of both the alloys after the experiment. Because the oxide scale of Inconel 617 has a loose structure, whereas that of Incoloy 800H is denser, Inconel 617 exhibited significantly more severe internal oxidation than Incoloy 800H. Further, Inconel 617 showed a significant decrease in ultimate tensile strength and plasticity after aging for 200 h, whereas Incoloy 800H maintained its tensile properties satisfactorily. Through control experiment under vacuum, we preliminarily concluded that serious internal oxidation is the primary reason for the decline in the tensile properties of Inconel 617.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.127-131
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• 1993

A new learning method of both NNI and NNC by which the NNI identifies precisely the dynamic characteristics of the plant is proposed. For control of ihe nonlinear plant we use two neural networks, one -for identification and the other for control. We define a closed loop en-or which depends on identification and control error. In the proposed learning method, the closed loop en-or is utilized to train the NNI and the NNC. Computer simulation results reveal that the NNC based on proposed method is insensitive to variations of the plant parameters.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.161-164
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• 2001

In this paper, we investigated the dielectric and piezoelectric properties of Pb(Sb, Nb)O$_3$-Pb(Zr, Ti)O$_3$ ceramic(PSN) for piezoelectric transformer and actuator etc. Effect of MnO$_2$ addition on the PSN ceramic was investigated. Anisotropic properties of electromechanical coupling factor and piezoelectric properties proved to be varied with amount of MnO$_2$ impurity and sintering temperature. The electromechanical coupling factor k$_{p}$ of 0.38 and the mechanical quality factor Q$_{m}$ of 1944 were obtained from the specimen with 0.4 wt% MnO$_2$ sintered at 115$0^{\circ}C$ addition. Experimental results indicated that the PSN ceramic with MnO$_2$ impurity can be effectively used for piezoelectric transformer and actuator.tor.

• 자원리싸이클링
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• 제7권1호
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• pp.41-49
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• 1998

알루미늄계 응집제를 사용한 수처리시 발생하는 슬러지를 산으로 처리하여 응집제를 회수하는 방안과 그로 인한 잔류 슬러지의 부피 및 질량감소, 탈수성질의 변화, 그리고 산처리시의 영향요인 등에 관해 논의하였다. 회수된 응집제의 특성은 알루미늄의 함량, 응집 효율성, 잔류 불순물들에 의해 평가될 수 있다. 산처리후 발생하는 잔류 슬러지의 처리방법 및 실제 공정 운영에의 적용사례 등에 관해서도 논의하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.603-606
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• 2004

Aspects of PD occurrence from PD sources are different with their physical and structural appearances which cause the variation of electric field distributions of them. This paper have investigated electric field distributions of some kinds of electrode structure by FEM applied analysis program. Numeric analysis is a good method to investigate Ihe electric and magnetic field distribution of partial discharge source. The analysis results were confirmed by real PD occurring situation in the laboratory.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1061-1064
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• 1997

Micro injection molding technology is very important fiw mass product of micro structures or micro parts. And, it is so difficult that the molding technology of micro pole or thin wall(barrier rib) structures with high aspect ratio. In this stud). \vc intend to research on the basic technology of micro wall structure part:< with high aspect ratio by the inject~on moldins method. The mold for esperimenrs with micro multi-square structures was made by L, I(;A process. One square polc's size is 157 157pm. height 50011111. And the distance of each poles is 5011n1. 7'hus. molding products will be for~nctl like as the net structure with thin wall of about 50pn thickness.(aspect ratio 10) Ihrough the e~lxriment. \be obtained the prociuctr of micro multi-square slructure with bout 37.000 cell per a piece. 'Ihe micro injection molding process technolog for thin wall by multi-square structure mold was analy~cd.

• 대한한의학회지
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• 제26권3호
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• pp.74-79
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• 2005

Objectives : The purpose of This study was to find the effect of Jeondo-gan (JDS) on acne. Methods : From December 1, 2003 to January 31, 2004, 11 patients with acne were observed, limited to patients who were teated with JDS for more than three weeks. JDS mined with cold water was used on outbreaks of acne, 15 minutes. 1 time per night, 6 times per week. Results & Conclusions : 3 males and 8 females were treated ever three weeks, The average age was 21.73 years old. Before treatment, ache patients had sparse papules on the forehead. both cheeks, and chin, After treatment over three weeks, nine acne patients changed for ihe better at a rate of $81.8\%$ (mild improved $54.6\%$, improved $18.2\%$, much improved $9\%$)

• 한국대기환경학회지
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• 제10권4호
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• pp.245-251
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• 1994

We considered that characteristics of SO$_2$, concentration level and relations of the meteorological parameters and high pollution concentration from the data measured 7 air quality continuous monitoring stations during 4 years, from 1990 to 1993 in Pusan. The SO$_2$ concentration level showed decreasing trend yearly, it was maximum in Winter, minimum in Summer. The time of SO$_2$ peak concentration lagged from seashore to land because of break-down of the nocturnal inversion layer and seabreeze. Ihe correlations of daily SO$_2$, value between various air quality continuous monitoring stations were highest between Beomcheondong and Meongryundong, lowest between Daeyeondong and Sinpyeongdong because of difference of air Pollution emission sources characteristic. The meteorological parameters affecting SO$_2$ concentration level were minimum temperature, relative humidity, wind speed and air pressure. The SO$_2$ high pollution($\geq$95ppb) occurred almost in Winter, particulaly in such day showing lower wind speed and higher air pressure. Elementary SO$_2$ high Pollution Predictor were high pressure system and stability of lower atmosphere.

• 미생물학회지
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• 제35권2호
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• pp.169-172
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• 1999

한천 사면배지 대신 한지를 사용하여 시험관내 뿌리혹생성 실험방법을 개선하였다. 개선된 이 방법은 기존의 한천-시험관 법에 비해 전체 과정이 간단하며, 특히 굵고 단단한 유근을 갖는 콩과식물에서도 효과적으로 사용할 수 있다. 이 방법을 사용하여 Bradyrhizobium sp. CN9135을 접종한 차풀에서 접종후 7일째부터 조사된 식물개체의 6%에서 뿌리혹이 생기기 시작하여 14일 째에 조사된 모든 식물개체에서 뿌리혹이 생성되었다.

• 수산해양기술연구
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• 제13권2호
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• pp.5-7
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• 1977

생식소 회복초기의 생태에 관한 조사결과는 다음과 같다. 1.까나리의 결장과 체중의 상대성장식은 다음과 같다. $W=0.0010114L^{2\cdot7281024}$ 2.체중,생식소 및 내장 중량 생식소으 ㅣ체중에 대한 비율은 0.27$\sim$0.87%로 생식소는 회복초기의 것이다. 내장의 체중에 대한 비율은 10.34$\sim$11.86%로 산란군의 생식소의 체중에 대한 비율과 비등하다. 3.척추골의 수 척추골의 평균치와 표준편차는 다음과 같다. $64.597\pm1.307$