• Journal of applied mathematics & informatics
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• 제7권1호
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• pp.247-255
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• 2000

The purpose of this paper is to give new existence theorems of equilibrium in abstract economies with uncountable number of agents and general preference correspondences.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.413-417
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• 2007

본 논문에서는 응용서비스 제공자가 망사업자의 망을 이용하여 응용서비스를 제공하고 망사업자에게 사용대가를 지불하는 경우를 다루었다. 우리는 Stackelberg 게임을 이용하여 두 사업자간의 계약(contract)설계 문제를 정형화하였고 이 게임의 균형점 (equilbrium)이 유일하다는 것을 보였고 또 이 균형점이 망사업자의 위험선호도에 따라서 어떻게 바뀌는지를 고찰하였다.

• Bulletin of the Korean Chemical Society
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• 제22권6호
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• pp.559-564
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• 2001

A method for calculating the main characteristics of a potentiometric titration curve in a carboxylic ion exchanger has been investigated. The potentiometric titration curves of simple electrolyte and ion exchangers (polyelectrolytes) showed a great difference between them. The acidity parameters of the ion exchangers, the thermodynamic constant (pK0), apparent equilibrium constant (K), and correction for the apparent equilibrium constant (b), were introduced and used to express the characteristics of the carboxylic ion exchanger. A characteristic equation related to the acidity parameters of the ion exchangers systems was derived. A fibrous carboxylic cation exchanger was used and potentiometric titration curves at different concentrations of the supporting electrolyte were obtained . To prove the validity of the characteristic equation, the concentration of the supporting electroyte was varied. In the present study, good agreement between the data points and the fitted curves was found in all the cases. The g (number of moles of alkali to 1 g of ion exchanger) of carboxylic ion exchanger was calculated from the concentration of supporting electrolyte (C), pH of the solution, and degree of neutralization of ion exchanger (x).

• 한국추진공학회지
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• 제12권3호
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• pp.9-15
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• 2008

고고도 추진 기관으로 개발되고 있는 항공우주연구원의 30톤급 액체 로켓 엔진 노즐 성능의 신뢰성 있는 성능 예측을 위하여 화학적 동결 및 평형 유동 해석을 수행하였다. 해석은 이전의 연구에서 개발된 해석 코드를 보완하여 수행하였다. 비평형 해석이 가장 신뢰할 만한 방법이기는 하지만 수렴특성과 불확실성을 고려할 때 연계된 동결 및 평형 해석이 비용측면에서 효율적인 방법임을 확인 할 수 있었다. 이 해석으로부터 노즐 유동의 팽창 과정에서 나타나는 화학적 재결합 효과에 의한 열 및 운동에너지의 회복 및 점성 효과를 고려한 신뢰성 있는 성능 예측을 할 수 있었다.

• 한국연초학회지
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• 제8권1호
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• pp.13-21
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• 1986

The fragility, which express the fineness index, increased linearly with the moisture content for various tobacco shreds and showed a high correlation to the moisture content. Then, fineness index (FIs) at reference moisture content(l2.5%) was obtained by following equation. FIs=FIm+A(12.5-Mm) A" denote the gradient of simple linear regression equation between the fineness index and moisture content. FIm; the fineness index measured at the standard moisture content(12.5%). The characteristics of fragility concerning with some kinds of tobacco raw materials, stalk position, moisture content and storaged time were investigated. The following results were obtained. 1. The moisture content range of less fragile of tobacco raw material was from 16% to 20%. whereas the rolled process sheet tobacco was from 12% to 16%. 2. The Bright yellow and the paper process sheet tobacco were less fragile than that of the other tobacco raw materials. 3. The leaves were more distant from middle stalk position, and its become more fragile. 4. Physical properties of the storaged tobacco leaves were determined as a function of each storageunction of each storage time. The long-term storaged leaves(more than 3 years) were slightly lighter weight, more fragility and lower equilbrium moisture content than thos of the mid-term storaged leaves.(less than 3 years). 5. Contents of chemical component of the storaged leaves were determined every storage time. The long-term storaged leaves were slightly lower content of nicotine and chlorine than those of mid-term storaged leaves, but contents of crude fiber, total ash and calcium were increased significantly.

• Journal of Korean Vacuum Science & Technology
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• 제4권3호
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• pp.81-85
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• 2000

The effects of $NH_3$ flow rate and reactor pressure on Al composition and the interface of AlGaN/GaN heterostructure were studied. Equilibrium partial pressure of Ga and Al over AiGaN alloy was calculated as a function of growth pressure, $NH_3$flow rate and temperature. It was found equilbrium vapor pressure of Al is significantly lower than that of Ga, thus, the alloy composition mainly controlled by Ga partial pressure. We believe that more decomposition of Ga occur at lower $NH_3$ flow rate and higher growth pressure leads to preferred Al incorporation into AlGaN. The alloy composition gradient became larger at AlGaN/GaN heterointerface at higher reactor pressures, higher Al composition and low $NH_3$ flow rate. This composition gradient lowered sheet carrier concentration and electron mobility as well. We obtained an AlGaN/GaN heterostructure with sheet carrier density of ${\sim}2{\times}10^{13}cm^{-2}$ and mobility of 1250 and 5000 $cm^2$/Vs at 300 K and 100 K, respectively.

• 한국환경과학회지
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• 제7권4호
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• pp.559-564
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• 1998

The effects of temperature, initial $Pb^{2+}$concentration and initial sludge concentration on the initial $Pb^{2+}$ removal rate and maximal $Pb^{2+}$removal amounts in activated sludge, respectively, were investigated. The removal of $Pb^{2+}$ in activated sludge was proved to be temperature-dependent process. The initial $Pb^{2+}$ removal rate increased from 187.5 to 261.4 mg $Pb^{2+}$/g sludge dry weight min, in response to the promoted temperature from 1$0^{\circ}C$ to 6$0^{\circ}C$, while the maximal $Pb^{2+}$removal amount (78.5 mg $Pb^{2+}$/g sludge dry weight) occurred at 30t . As the initial $Pb^{2+}$concentration increased from 36 to 228 mg $Pb^{2+}$/L at the constant temperature of 30C and initial sludge concentration of 1.5 g sludge dry weight/L, the time to reach an equilibrium state was almost independent of the initial $Pb^{2+}$concentration and the equilibrium $Pb^{2+}$/removal amount was increased Irom 41.9 to 73.6 mg $Pb^{2+}$/g sludge dry weight. On the contrary, the equilbrium $Pb^{2+}$ emoval amount was decreased from 87.7 to 65.3 mg $Pb^{2+}$/g sludge dry weight as the in- crease of initial sludge concentration from 0.22 to 1.76 g sludge dry weight/L.

• 한국잠사곤충학회지
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• 제38권1호
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• pp.25-30
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• 1996

견 피브로인 섬유에 의한 Cr(VI)의 흡착 특성을 분석하였다. Cr(VI)의 흡착평형은 초기 흡착속도에 큰 영향을 받고 있으며 평형흡착량의 52% 정도에 이르고 있다. 견 피브로인 섬유에 의한 Cr(VI)의 흡착은 크롬염의 산화반응을 일으키는 산성의 pH 범위에서 흡착량이 증가한다. Cr(VI)의 흡착온도에 대한 엔탈피($\Delta$H)의 변화는 39.7KJ.mol-1로 얻어졌다. 이것은 Cr(VI)의 흡착이 착제 화학적 반응이라는 것을 의미하며 IR 스펙트럼의 결과에서도 아미드 형 카르보닐의 배위에 의한 착물형성이 확인되었다. 또한, 견 피브로인 섬유의 크롬 흡착처리에서 물성의 과도한 저하를 고려한 조건은 온도 5$0^{\circ}C$ pH 2.4, 3시간의 처리가 적당하고 5 X 10-3M의 농도에서 흡착평형에 도달하였다.

• 한국세라믹학회지
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• 제36권8호
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• pp.813-819
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• 1999

Ion implantation, photo-lithography, Ar ion milling과 hot press 법을 이용한 micro-fabrication techrique을 사용하여 고순도 알루미나 단결정인 사파이어의 내부에, 조절된 Ca의 첨가량을 갖고 있는, crack과 비슷한 형태의 기공들을 형성시켰다. 이 bi-cryslal을 각각의 온도에서 열처리하여 Ca 이온이 고온에서 알루미나의 morphology와 hcaling에 미치는 영향을 관찰하였다. 열처리 온도가 올라감에 따라서 crack-like pore의 내부에 hcxagonal bridging ligaments가 생성되었는데, 열처리 온도와 Ca의 첨가량이 증가할수록 크기가 커지는 것을 관찰할 수 있었고, 생성된 hexagonal bndgmg ligaments는 열처리가 진행됨에 따라 서서히 커지면서 모서리가 둥글어지는 현상을 관찰할 수 있었다. Bicrystal 내부에 형성된 crack-like pore는 열처리가 진행되면서 edge regression. ligamcnt growth 및 flow의 3가지의 특징적인 형태로 진행되었다. 이때 edge regression은 상대적으로 저온에서부터 전체 crack-like pore에서 서서히 일어나기 시작하였으며, ligament growth는 일부 crack-like pore에서 진행되있으며, 대단히 빠른 속도로 crack healing이 진행됨을 추정할 수 있었다. Flow는 $1800^{\circ}C$ 이상의 고온에서 모든 crack-like pore에 걸쳐서 느리게 일어남을 알 수 있었다.

• 상하수도학회지
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• 제9권3호
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• pp.116-126
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• 1995

The purpose of this study was to investigate the removal of ammonium nitrogen by biological nitrification in raw water containing LAS using BAC. At batch teats, LAS removal by ozone followed the first order reaction, and the rate constants(k) by ozone dose 1, 3mg/min.L were $0.040min^{-1}$, $0.062min^{-1}$ respectively. Therefore, the more ozone was dosed, the higher LAS was removed The reaction between ozone and ammonium nitrogen also followed the first order, and rate constants(k) at pH7,8 and 9 were $8.9{\times}10^{-4}min-1$, $3.8{\times}10^{-3}min^{-1}$, and $2.9{\times}10^{-2}min^{-1}$ respectively at ozone dose of 3mg/min.L . Therefore, ammonium nitrogen was little removed by ozone under neutral pH of 7. The continuous flow apparatus had four sets composed of a ozone contacter and a GAC column. Through continuous filtration test for 50days, the following conclusions were derived; (1) LAS was removed 23%, 30% respectively by ozone dose 1, 3mg/L, and was not detected in all column effluents during the period of experiment. Therefore, it appeared that adsorption capacities of each column still remained. (2) Ammonium nitrogen concentration after ozone contact varied little in raw Water because pH of raw water was from 6 to 7, and was transfered to nitrite and nitrate within GAC columns as the result of staged nitrification. After 30days, nitrite was not detected in all column effluents due to biological equilbrium between nitro semonas and nitrobacter Average removals of ammonium nitrogen in each column after the lapse of 30days were the following; ${\cdot}$ column A (ozone dose 3mg/L, EBCT 9.5min): about 100% ${\cdot}$ column B (ozone dose 1mg/L, EBCT 9.5min): 91% ${\cdot}$ column C (ozone dose 3mg/L, EBCT 14.2min): about 100% ${\cdot}$ column D (ozone dose 0mg/L, EBCT 9.5min): 53% Though column A and C reached nitrification of about 100%, column C (longer EBCT than column A) was more stable than column A. (3) After backwash, nitrification reached steady state within 5 to 8 hours. Therefore, nitrification was not greatly affected by backwash. (4) According to the nitrification capacity in depth of column A, C, where 100% nitrification occured. LAS was removed within 20cm, while ammonium nitrogen required more depth to be removed by nitrification.