• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.845-848
• /
• 2006

This study sought to investigate the characteristics of cellular concrete, such as porosity, strength and density, according to the cell addition rate. Based on the result, it examined the application to a cellular concrete panel. Porosity was found to increase according to the cell addition rate, measuring continuous porosity of 42% and 47%, and total porosity of 61% and 66%. In terms of cell addition rate, measurements were 7% and 11% respectively. Compressive strength represented 5.0MPa, 3.8MPa and 2.8 MPa in terms of 7%, 9% and 11% respectively, decreasing 1 MPa of strength according to every 2% increase of cell addition rate. Density showed 0.55, 0.44 and 0.36 in terms of 7%, 9% and 11% respectively, decreasing 1.0 MPa according to every 2% increase of cell addition rate proportionally. In addition the sandwich panel of cellular concrete which was fabricated during this research was found to be relatively heavy and non-flammable with an excellent strength of 4.0 MPa. Compared with a light concrete panel, considering the compressive strength that accountsfor 10 MPa, it appeared relatively low in strength. However it would be excellent for application due to the light density of only 0.4 MPa.

• Biomolecules & Therapeutics
• /
• 제7권3호
• /
• pp.216-220
• /
• 1999

A chemosensitivity assay with small replicate Mm5mt/cl C3H mammary tumor cell cultures was developed to determine whether changes in viral antigen expression and release into culture fluids could be utilized as an in vitro measure of modulating drug effect. The 52,000 MW viral envelope glycoprotein (gp52) of the mouse mammary tumor virus (MMTV) was measured in culture fluids of control and drug-treated cultures while cell density was simultaneously determined by cell staining and OD 664 nm determination. While extra-cellular gp52 levels and cell density progressively increased over 72 hours for control cultures, declines in both parameters provided dual measures of effect for combination [N(phophonacetyl-L-aspartic acid)+5-fluorouracil], combination 〔N(phophonacetyl-L-aspartic acid )+5-fluoro-5'-deoxyuridine〕and single component treatment of this combination. At each treated time point, thesecombinations begin to produce a greater decline in both cell density and gp52 levels as compared to single drug treatments. These results indicate that N(phopho-nacetyl-L-aspartic acid) in combination can enhance the effectiveness of single drug.

• ETRI Journal
• /
• 제42권1호
• /
• pp.129-137
• /
• 2020

All-solid-state batteries are promising energy storage devices in which high-energy-density and superior safety can be obtained by efficient cell design and the use of nonflammable solid electrolytes, respectively. This paper presents a systematic study of experimental factors that affect the electrochemical performance of all-solid-state batteries. The morphological changes in composite electrodes fabricated using different mixing speeds are carefully observed, and the corresponding electrochemical performances are evaluated in symmetric cell and half-cell configurations. We also investigate the effect of the composite electrode thickness at different charge/discharge rates for the realization of all-solid-state batteries with high-energy-density. The results of this investigation confirm a consistent relationship between the cell capacity and the ionic resistance within the composite electrodes. Finally, a concentration-gradient composite electrode design is presented for enhanced power density in thick composite electrodes; it provides a promising route to improving the cell performance simply by composite electrode design.

• KSBB Journal
• /
• 제4권2호
• /
• pp.143-149
• /
• 1989

하이브리도마 세포를 고농도 배양하기 위하여 세포 침전장치를 고안하여 사용하였다. 위로 올라갈수록 직경이 넓어지는 침전조는 세포의 침전이 잘 일어나지만 침전된 세포가 침전조 벽에 누적되는 결점을 보였고, 아래 위의 직경이 균일한 침전조는 희석율이 높아질수록 유출되는 세포가 증가하는 문제점을 나타내었다. 특히 유출되는 세포속에는 dead cell 보다 viable cell의 비율이 높아 배양기 내의 dead cell이 급격히 농축되는 현상을 보였다. 그러나 침전조를 적절히 고안하여 세포 누적 현상을 막고 동시에 세포 유출을 완화시킬 경우 세포농도 $5{\times}10^6$ cells/ ml에서 일주일간 배양이 가능했다. cell viability의 측정이 용이하므로 침전조를 이용한 하이브리도마 고농도 배양의 특성을 연구하는데 많은 도움을 줄 수 있을 것으로 판단된다.

• 생태와환경
• /
• 제34권3호통권95호
• /
• pp.175-184
• /
• 2001

방류수내 남조류 세포의 밀포와 종조성 및 독소의 계절별, 일일 변화를 일본 중심에 위치하고 있는 Suwa호의 수문에서 1998년 5월부터 10월까지 조사하였다. Microcystis의 높은 세포밀도가 M. ichthyoblabe가 우점했던 7월과 M. viridis가 우점종으로 나타난 9월에 관찰되었다. Microcystis의 종조성과 총 세포밀도는 3종류의 microcystin의 정성${\cdot}$정량적인 변화와 관련이 있었다. M. ichthyoblabe가 우점했던 7월 동안에는 MC-RR과MC-LR만이 검출되었으나 M. aeruginosa의 개체수 증가와 함께 M. viridis가 우점종으로 나타난 8월부터 10월까지는 MC-YR을 포함한 3종류의 microcystin 모두 검출되었다. 방류수내 Microcystis의 세포밀포와 microcystin의 함량의 일 변화는 바람의 일 변화에 큰 영향을 받았다. 아침에 비해 오후에 바람이 강하게 부는 풍속주기의 조건에서 Microcystis의 세포밀도와 독소의 함량은 아침에 증가하고 오후에 감소하는 경향을 나타냈다. 본 연구의 결과들은 수문이나 취수탑에서 방류시기의 조절은 부영양 호수에서 물을 취수하여 이용함에 있어 원수내 조류의 생물량을 저감할 수 있는 유효한 방법임을 제시한다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.379-381
• /
• 2009

The simulation model for metal-supported Solid Oxide Fuel Cell(SOFC) is developed in this study. Open circuit voltage is calculated using Nernst equation and Gibbs free energy is required by thermodynamic. The exchange current densities are compared with experimental results since exchange current density is most effective factor for the activation loss. Liu's study is used for the exchange current density of cathode, BSCF, and Koide's result is applied for the exchange current density of anode, Ni/YSZ. For the ohmic loss, ionic conductivity of YSZ is described from Kilner's mode and the data are compared with Wanzenberg's experimental data. Diffusivity is an important factor for the mass transfer through the porous medium. Both binary diffusion and Knudsen diffusion are considered as the diffusion mechanism. For validation, simulation results at this work are compared with our experimental results.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
• /
• pp.59-62
• /
• 2000

As the density of memories increases, unwanted interference between cells and coupling noise between bit-lines are increased and testing high density memories for a high degree of fault coverage can require either a relatively large number of test vectors or a significant amount of additional test circuitry. From now on, conventional test algorithms have focused on faults between neighborhood cells, not neighborhood bit-lines. In this paper, a new algorithm for NPSFs, and neighborhood bit-line sensitive faults (NBLSFs) based on the NPSFs are proposed. Instead of the conventional five-cell and nine-cell physical neighborhood layouts to test memory cells, a three-cell layout which is minimum size for NBLSFs detection is used. To consider faults by maximum coupling noise by neighborhood bit-lines, we added refresh operation after write operation in the test procedure(i.e., write \longrightarrow refresh \longrightarrow read). Also, we present properties of the algorithm, such as its capability to detect stuck-at faults, transition faults, conventional pattern sensitive faults, and neighborhood bit-line sensitive faults.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2004년도 추계 학술대회논문집
• /
• pp.141-144
• /
• 2004

An analysis procedure for the MCFC channel flow has been developed to predict the fuel cell performance. The channel formed by the uniformly distributed trapezoidal supports is approximated by the porous medium that yields the equivalent pressure drop. The Wavier-Stokes, energy, and species equations are solved to obtain the velocity, temperature and concentration fields for a local current density which is computed from electrochemical correlations. The fuel cell characteristics, such as the temperature, pressure, mole concentration, voltage and current density distributions, are presented and discussed.

• Journal of Microbiology and Biotechnology
• /
• 제1권2호
• /
• pp.126-129
• /
• 1991

In order to produce ${\gamma}-linolenic$ acid by Mucor sp. KCTC 8405P. the fungus was cultivated in fed-batch culture with two phases. i.e., growth in yeast-like form and induction to hyphal growth by pH shift of the culture medium during cultivation. The synchronous growth of the fungus into the appropriate sizes was important for the high density cell culture of this dimorphic fungus. Dissolved oxygen concentration in the medium did not affect degree of unsaturation of fatty acids and ${\gamma}-linolenic$ acid content. Under the culture conditions applied in this experiment. the fungus was found to produce 100 g/l dry mycelia containing 40% of the lipids, where ${\gamma}-linolenic$ acid comprised about 9% of the total extractable fatty acids.

• 설비공학논문집
• /
• 제6권2호
• /
• pp.120-129
• /
• 1994

A numerical investigation has been carried out for the electrochemical reaction, mass and heat transfer characteristics of the Molten Carbonate Fuel Cell(MCFC) stack. The effects of cooling air channel and water gas shift reaction were taken into account. The current density distribution of electrodes, the molecular fractions of reactant gasses and three dimensional temperature distribution can be calculated and shown by several lines of equivalent values. The results have been compared with the existing ones, and reasonable agreement has been obtained. To examine the influence of changing parameters, such as the composition of reactant gases, the target average current density, the utilization of reactant gases, the cooling air inlet temperature and flow rates, the computer simulation has been done. The analysis method and computer program developed in this study will be greatly helpful to design and verify the optimum operating condition of MCFC stack.