• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.1
• /
• pp.25-30
• /
• 2005

In order to decrease the high costs of membrane process, we have tried to develop two alternatives to membrane; a cartridge type filter and a metal membrane were tested for the high permeation flux with low cost and low energy. This research mainly focused on three points; 1) operation with high permeation flux by using of a cartridge type filter and a metal membrane, 2) removals of the filterable organic materials (FOC) by pretreatments for the membrane fouling control, and 3) advanced wastewater treatment by SMBR process with intermittent aeration and high MLSS. An Intermittently aerated membrane bioreactor using a submerged micro filter (cartridge type) was applied in laboratory scale for the advanced wastewater treatment. To minimize membrane fouling, intermittent aeration was applied inside of the filter with $3.0kg_f/cm^2$. The experiments was conducted for 6 months with three different HRTs (8, 10, 12 hr) and high MLSS of 6,000 and 10,000mg/L. The filtration process could be operated up to 50 days with permeation flux of 500LMH. Regardless of the operating conditions, more than 95% of COD, BOD and SS were removed. Fast and complete nitrification was accomplished, and denitrification was appeared to be the rate-limiting step. More than 75% T-N could be removed due to the endogenous denitrification. T-P removal efficiency was increased to 80% under the condition of MLSS 10,000mg/L.

• Korean Membrane Journal
• /
• v.6 no.1
• /
• pp.16-23
• /
• 2004

The silica containing carbon (C-SiO$_2$) membranes were fabricated using poly(imide siloxane) (PIS) having -CO- swivel group. The characteristics of porous C-SiO$_2$ structures prepared by the pyrolysis of poly(imide siloxane) were related with the micro-phase separation between the imide block and the siloxane block. Furthermore, the nitrogen adsorption isotherms of the CMS and the C-SiO$_2$ membranes were investigated to define the characteristics of porous structures. The C-SiO$_2$ membranes derived from PIS showed the type IV isotherm and possessed the hysteresis loop, which was associated with the mesoporous carbon structures, while the CMS membranes derived from PI showed the type I isotherm. For the molecular sieving probe, the C-SiO$_2$ membranes pyrolyzed at 550, 600, and 700$^{\circ}C$ showed the O$_2$ permeability of 924, 1076, and 367 Barrer (1 ${\times}$ 10$\^$-10/㎤(STP)cm/$\textrm{cm}^2$$.$s$.$cmHg) and O$_2$/N$_2$ selectivity of 9, 8, and 12.

• Membrane Journal
• /
• v.27 no.6
• /
• pp.469-476
• /
• 2017

Membrane separation is a technology of low energy consumption. Membranes made of zeolites are of great interest because their fixed and open pores in the size of small molecules inside crystalline structures allow separation processes under harsh conditions. While zeolite NaA (LTA-type) is industrially used for dewatering of organic solvents, its pore size and thermal and hydrothermal stability can be tuned by exchange of framework and extra-framework elements. SOD with pores of only 0.28 nm is of great interest for $H_2$- und $H_2O$-separation and also can be tuned by ion exchange. Zeolites open the opportunity to create membranes of adapted separation behavior for small molecules in conditions of surrounding technical processes.

• Korean Journal of Plant Resources
• /
• v.8 no.3
• /
• pp.237-246
• /
• 1995

In this study, the callus was induced and regenerated from the immature embryo and ultrastructural characteristics of developmental stages in Citrus junos SIEB, were investigated. The yellowish callus was induced by 5 to 6 week of culture of citrus. In proliferation callus after 6 weeks of culture, large vacuole was formed by fusion between adjacent small ones. In the non-embryogenic callus cultured for 12weeks, re-differentiated cells of callus showed the large nucleus with globular nucleus and amyloplast with large size of starches. In the embryogenic callus cltured for 14-16 weeks, the active exocytosis occurred in cells, secretory vesicles appeared on cell membrane and small particles from cytoplasm were released to intercelluar space. In the embryogenic callus cultured for 24 weeks, a sperical type of chloroplast bounded on cytoplasm by double membrane and typical grana was dispersed equally among matrix. In the normal plantlet after 26 weeks of culture, a lot of vessels and companion cells apperaed in the leaf cell of plantlet. In the normal plantlet after 30 weeks of culture, the immature leaf showed many small companion cells, sieve tubes and central vacuole. Also, the secondary vacuole protruded into the central vacuole and elongated chloroplasts near plasma membrane. In the matured plant habituated on the soil, palisada tissue composed of orderly arranged cells contained the nucleus in the center of the cell and large vacuoles on either side of the nucleus.

• Journal of the Korea Institute of Building Construction
• /
• v.2 no.3
• /
• pp.163-170
• /
• 2002

Recently, polishing tile(porcelain homogeneous polished tile) was used in the construction field as a finishing material. But, there happened some problems such as tile exfoliation by construction condition in early ages. Also, for use of polishing tile in the dry wall system which used to lightweight wall, the examination of adhesive stability of polishing tile is needed. In this study, adhesive strength of Polishing tile was investigated by tile bond types on gypsum board and non asbestos board coated by tar-urethane and Polymer modified cementitious waterproofing membrane(Series I). Then, the effect of heat stress and vibration was estimated on gypsum and non asbestos board(Series II). As the result of study are the follows; (1) Polishing tile(600$\times$400mm) construction on waterproofing layer : Both laboratory estimation and spot examination sieve were happened that fall of tile because their hardening speed is late. (2) To using powder style adhesives in the dry wail with waterproofing layer : Adhesive strength of tile is Influenced by interface bond area and base side condition. (3) Shock and heat stresses : obvious decline of adhesive strength is not happened