• KCID journal
• /
• v.1 no.2
• /
• pp.48-59
• /
• 1994

여러가지의 유사이동 공식들은 각 저자들의 실험실이나 현장실측치를 바탕으로 발표되었다. 그리고 저자에 따라서 본인들의 공식의 적용한계를 명백히 명시한 것도 있지만 그렇지 않은 것도 많다. 동일한 수리학적 조건에서 이 공식들이 현장에서 적용될 때 이 공식에 의한 유사량은 공식에 따라서 유사한 것도 있고 차이가 많이 나는 것도 있다. 특히 St. Venant식(물의 연속 방정식과 물의 운동량 방정식)과 유사 연속방정식을 연립하여 컴퓨터 모의시험에 이용할 때

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2002.04a
• /
• pp.27-27
• /
• 2002

본 연구에서는 상용코드 FLUENT를 통한 수치모사 결과를 바탕으로 개발한 이중 원호익형의 성능상관식을 축류펌프의 설계에 적용하여 보았다. 일반적으로 익형의 설계는 크게 두 단계를 거치게 된다. 먼저 반경방향의 평형과 설계조건을 만족하는 임펠러와 디퓨저의 입구와 출구의 속도 삼각형을 얻고, 다음으로 적당한 익형을 선택하여 기하학적 형상을 결정하는 과정으로 이루어져 있다.

• Journal of the KSME
• /
• v.35 no.2
• /
• pp.154-166
• /
• 1995

냉동\ulcorner공조기의 성능을 높이기 위해서는 정상상태 운전시는 물론 증발기 열부하 등 각종 작동 조건의 변화에 대응하여 운전의 평형점(balance point) 추이를 적절하게 조정함과 동시에 냉동 사이클 각부의 냉매 상태량을 과도적으로도 제어해야 한다. 이 글에서는 냉동\ulcorner공조기의 자동 제어에 있어서 가장 중요한 요소중의 하나인 냉매계통의 모델화와 냉동 사이클의 응답 및 제어 등에 관해서 서술하고자 한다.

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.2872-2875
• /
• 1999

본 논문은 주어진 적합한 이진 패턴들의 집합이 점근적으로 안정한 평형점들로써 저장되는 최적으로 성능을 갖는 GBSB (generalized brain-state-in-a-box)의 설계가 고려된다. GBSB 모델의 정성적 특성에 기초하여, 설계 문제가 제약 조건을 가한 최적화 문제로 공식화된다. 다음으로, 우리는 이 문제를 GEVP (generalized eigenvalue Problem)라고 불리는 최적화 문제로 변환한다. 제안된 방법을 예증하기 위함과 기존의 방법과의 비교를 위해서 설계 예제가 주어진다.

• Proceedings of the KSEEG Conference
• /
• 2003.04a
• /
• pp.238-240
• /
• 2003

본 연구는 덕음광산 광미시료에 대한 각 pH별 중금속 거동 및 본 지역에서 중금속과 밀접한 관계를 가지는 토양광물인 Mn-함유광물의 용해도의 상관성을 규명하고자 한다. 본 연구를 통하여 Mn-함유광물의 용해도에 따른 중금속의 거동간의 상관관계를 알아봄으로서 광산 주변 지역의 지구화학적인 변화를 예측하고 오염지역 특성을 정확하게 이해할수 있도록 정보를 제공하고자 하였다. (중략)

• Applied Chemistry for Engineering
• /
• v.9 no.1
• /
• pp.107-114
• /
• 1998

The solubilities of $CO_2$ in 20wt% and 30wt% aqueous AMP solution were obtained from experiments at 40, 50, 60, 70, $80^{\circ}C$. Using the modified Kent-Eisenberg model, equilibrium constants and correlations were determined from the regression of experimental results of 30wt% aqueous AMP solution. There were good agreements between the predicted $CO_2$ solubilities in 20wt% aqueous AMP solution and experimented values. The prediction was conducted at the condition in the literature and the predicted values calculated from the model and correlations which were obtained from this work agree well with the prediction from Deshmukh-Mather model. Thus, the modified Kent-Eisenberg model and correlated equations suggested by this work, resonably well represent vapor-liquid equilibrium of $CO_2$ with aqueous AMP solution. The calculation of chemical species concentration in the liquid phase was performed uslng equilibrium model and from this calculation, we confirm that good absorption capacity is due to the formation of unstable carbamate. Heat of solution(${\Delta}Hs$) was calculated from the solubility data using the Gibbs-Helmholtz equation.

• Korean Journal of Agricultural Science
• /
• v.16 no.1
• /
• pp.118-128
• /
• 1989

This experiment was conducted to study the relation between the equilibrium moisture contents and the hygroscopic components in the various tobacco matters such as NC-82, Br-21, R.T.S., and puffed stem. The order of the high equilibrium moisture contents was the puffed stem, R.T.S., NC-82, and Br-21. The H-1 grades of NC-82 and Br-21 contained high contents of total sugar had higher equilibrium moisture contents than others. The moisture contents in NC-82 and Br-21 were increased at higher temperature, $30^{\circ}C$ than $20^{\circ}C$. The grades with high amounts of water extracts and total sugar affected to increase the equilibrium moisture contents in NC-82 and Br-21. In conclusion, the equilibrium contents were related to the structure of tobacco matter, the grades, the temperature, and the amount of some chemical components such as water extracts and total sugar of the leaf tobacco.

• Korean Chemical Engineering Research
• /
• v.44 no.6
• /
• pp.623-630
• /
• 2006

The slag viscosity is an important factor determining the operation temperature of entrained flow type of gasifiers. The temperature of critical viscosity, $T_{cv}$, for 5 crystalline slags was predicted by empirical models and FactSage equilibrium calculations, and the validity of each method was tested. Two empirical models were employed: one using $T_h$ from the ash fusion test, and the other using the concentrations of 5 major components. The first model using $T_h$ over-predicted $T_{cv}$ by $20{\sim}100^{\circ}C$, while the model based on the slag composition under-predicted $T_{cv}$ by $80{\sim}120^{\circ}C$. In the equlibrium calculations, $T_{cv}$ was obtained from the liquidus temperature. When the 4-major component concentrations were used in the calculation, the predicted temperatures were higher than the observed. The liquidus temperature was very sensitive to the concentrations of minor components, and the addition of MgO and $Na_2O$ lowered the liquidus temperature. The results with 4 major and 3 minor components most closely described experimentally observed $T_{cv}$. In the case that a chromia refractory was used, it was shown that $Cr_2O_3$ concentration in the slag also needs to be included for more accurate prediction of $T_{cv}$.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.426-433
• /
• 2020

This study aimed to compare the pretreatment methods of phytoplankton for type approval of the Ballast Water Treatment System (BWMS). The International Maritime Organization (IMO) and the United States Maritime Police (USCG) use two different test methods for this purpose. To compare the two methods, a test for concentration and non-concentration was performed with cultured and natural phytoplankton, and samples from the land-based BWMS test. The extent of damages caused by the process of concentration varied between cultured and natural species, indicating differences depending on the physiological and morphological characteristics of the species. In the land-based test, in the control water with a high biological population, the number of non-concentrated samples was about twice as high as that of the concentrated samples. There was no distinct difference between the two methods in the treated water with a low biological population. Thus, although there is a difference between concentration and non-concentration for phytoplankton sampling, the concentration method can be applied as a method of evaluating BWMS performance. However, a method for evaluating whether live species in treated water may be lost or damaged during the concentration process of sampling should be developed and validated.

• Parasites, Hosts and Diseases
• /
• v.30 no.2
• /
• pp.65-74
• /
• 1992

The tegumental ultrastructure of juvenile and adult Echinostoma cinetorchis (Trematoda: Echinostomatidae) was observed by scanning electron microscopy. Three-day (juvenile) and 16-day (adult) worms were harvested from rats (Sprague-Dawley) experimentally fed the metacercariae from the laboratory-infected fresh water snail, Hippeutis cantori. The worms were fifed with 2.5% glutaraldehyde, processed routinely, and observed by an ISI Korea DS-130 scanning electron microscope. The 3-day old juvenile worms were elongated and ventrally curved, with their ventral sucker near the anterior two-fifths of the body. The head crown was bearing 37∼38 collar spines arranged in a zigzag pattern. The lips of the oral and ventral suckers had 8 and 5 type II sensory papillae respectively, and bewteen the spines, a few type III papillae were observed. Tongue or spade-shape spines were distributed anteriorly to the ventral sucker, whereas peg-like spines were distributed posteriorly and became sparse toward the posterior body. The spines of the dorsal surface were similar to those of the ventral surface. The 16-day old adults were leaf-like, and their oral and ventral suckers were located very closely. Aspinous head crown, oral and ventral suckers had type II and type III sensory papillae, and numerous type I papillae were distributed on the tegument anterior to the ventral sucker. Scale-like spines, with broad base and round tip, were distributed densely on the tegument anterior to the ventral sucker but they became sparse posteriorly. At the dorsal surface, spines were observed at times only at the anterior body. The results showed that the tegument of E. cinetorchis is similar to that of other echinostomes, but differs in the number and arrangement of collar spines, shape and distribution of tegumenal spines, and type and distribution of sensory papillae.