• Cement Symposium
• /
• s.34
• /
• pp.73-79
• /
• 2007

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2008.05a
• /
• pp.11.2-11.2
• /
• 2008

• Membrane Journal
• /
• v.26 no.4
• /
• pp.266-272
• /
• 2016

The separation and purification of lysozyme enzyme from chicken egg white (CEW) solution was studied using the dead-end filtration. The optimum operation conditions of the dead-end filtration reveal that the maximum value of permselectivity of lysozyme to the other proteins of ovalbumin and conalbumin in the CEW solution was tested with change of molecular weight cut-off (MWCO) of ultrafitration membrane and pH of the CEW solution. The optimum operation conditions for the efficient permeable separation of lysozyme from the CEW solution are that the membrane MWCO is 30 kD and the pH of CEW solution is 11. At this optimum operation conditions, the maximum value of permselectivity of lysozyme to total proteins in CEW solution is about 83.

• Membrane Journal
• /
• v.24 no.4
• /
• pp.317-324
• /
• 2014

It is very well known that the conventional polyamide (PA) thin film composite (TFC) reverse osmosis (RO) membranes have excellent permselective properties, but their chlorine tolerance is not good enough. In this study, to improve such chlorine tolerance, microporous membranes containing hydrophilic functional groups such as -COOH were used as a support to prepare PA TFC RO membranes, employing the conventional interfacial polymerization method. Meta-phenylene diamine (MPD) and 2,6-diamine toluene (2,6-DAT) were used as diamine monomers and tri-mesoyl chloride (TMC) as an acid monomer. The membranes prepared were characterized using various instrumental analytical methods and permeation test set-up. The flux obtained from the membranes prepared so was more than $1.0m^3/m^2day$ at 800 psi of operating pressure, while the salt rejection was over 99.0%. The chlorine tolerance of them was also found to be better than that of the membrane prepared by using conventional polysulfone support without hydrophilic functional groups.

• Korean Journal of Optics and Photonics
• /
• v.26 no.2
• /
• pp.103-109
• /
• 2015

In an amplitude-splitting interferometer, a beam splitter divides an input beam into two parts, which are superposed after propagating along separate paths, producing an interference effect. We have investigated the phase relation between the reflected and transmitted light waves at BS's made of lossless dielectric stacks. If we define the phases with proper reference planes, a definite phase relation exists, irrespective of the detailed structure of the layers in the BS. Although this results from the generalized Stokes relations, we have verified it numerically for two representative BS's with symmetric and asymmetric layer structures respectively. When we applied the phase relation to interferometers, we could determine the superposition state of the output beam (either constructive or destructive interference) for a general BS, and could verify that the light's energy was conserved.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.12
• /
• pp.761-768
• /
• 2016

Membranes are used to separate pure gas from gas mixtures. In this study, three different types of mass transport through a membrane were developed in order to investigate the gas separation capabilities of a membrane. The three different models typically used are a lumped model, a multi-cell model, and a discretization model. Despite the multi-cell model producing similar results to a discretization model, the discretization model was selected for this investigation, due to the cell number dependence of a multi-cell model. The mass transport model was then used to investigate the effects of pressure difference, flow rate, total exposed area, and permeability. The results showed that the pressure difference increased with the stage cut, but the selectivity was a trade-off for the increasing pressure difference. Additionally, even though permeability is an important parameter, the selectivity and stage cut of the membrane converged as permeability increased.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.2 no.1
• /
• pp.50-58
• /
• 1998

Water vapor transmission was tested in water bath controlled by $20^{\cire}C$, 90%RH for T800/AD6005 based composite motor case which made by filament winding method. We detected internal relative humidity of composite motor case by inserting the humidity detector through the head of motor case for the study of humidity transmission through the wall of composite motor case. We found out that this composite material appears the water vapor flux of 2.88${\times}$$10^{-9}$g/$\textrm{m}^2$sec and diffusivity of 7.98${\times}$$10^{-7}$$\textrm{mm}^2$/sec at $20^{\cire}C$, 90%RH water vapor condition.

• Journal of Energy Engineering
• /
• v.10 no.3
• /
• pp.266-271
• /
• 2001

Buoyancy-driven natural convection is analysed by employing a linear stability theory in hori-zontal porous media with net through flow. Darcy's law is used to model the flow characteristics in porous media. Bated on the results of linear stability analysis, a heat transfer correlation was obtained by employing weakly nonlinear analysis. As the net through flow increases, the system becomes more stable and the effect of the Darcy-Rayleigh number on the Nusselt number decreases.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1999.11a
• /
• pp.181-186
• /
• 1999

화학 축열 시스템의 성능을 모사하고 이를 해석하여 시스템 성능을 최적화하기 위해서는, 반응층의 열 및 물질 전달 특성을 정확히 아는 것이 중요하다. 본 연구에서는 $Na_2$S-$H_2O$ 반응계를 사용한 화학 열펌프에 대한 연구로, $Na_2$S-팽창흑연 복합체의 열전도도와 기체 투과도를 측정하였고, 소형 시스템을 제작하여 그 성능을 평가하였다. 열전도도는 전이 일차원 열류기법을 사용하여 측정하였고, 기체 투과도는 Darcy's law를 이용하여 측정하였다. 반응층의 열전도도와 기체 투과도는 팽창흑연 지지체의 겉보기 밀도와 반응염의 함량에 따라 각각 6~48W/mㆍK, 1.1$\times$$10^{-13}$~1.0$\times$$10^{-11}$m$^2$의 범위에 있었다. 또한 소형 시스템을 구성하여 445W/kgㆍ$Na_2$S의 냉방 출력을 얻을 수 있었다.

• Membrane Journal
• /
• v.33 no.6
• /
• pp.315-324
• /
• 2023

Ion-exchange membrane (IEM), is a key component that determines the performance of the electro-membrane processes. In this review, the latest research trends in improving the performance of IEMs used in various electro-membrane processes through modification using carbon-based and metal-based nanomaterials are investigated. The nanomaterials can be introduced into IEMs through various methods. In particular, carbon-based nanomaterials can strengthen their interaction with polymer chains by introducing additional functional groups through chemical modification. Through this, not only can the ion conductivity of IEM be improved, but also the permselectivity can be improved through the sieving effect through the layered structure. Meanwhile, metal-based nanomaterials can improve permselectivity through sieving properties using the difference in hydration radius between target ions and excluded ions within a membrane by using the property of having a layered or porous structure. In addition, depending on the characteristics of the binder used, ion conductivity can be improved through interaction between nanomaterials and binders. From this review, it can be seen that the properties of IEMs can be effectively controlled using carbon-based and metal-based nanomaterials and that research on this is important to greatly improve the performance of the electro-membrane process.