• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.11-15
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• 2016

Proton Exchange Membrane Fuel Cells (PEMFC) instead of batteries is appropriate for long time flight of unmanned aero vehicles (UAV). In this work, $NaBH_4$ hydrolysis system supplying hydrogen to PEMFC was studied. In order to decrease weight of $NaBH_4$ hydrolysis system, enhancement of hydrogen yield, recovery of condensing water and maintenance of stable hydrogen yield were studied. The hydrogen yield of 3.4% was increased by controlling of hydrogen pressure in hydrolysis reactor. Condensing water formed during air cooling of hydrogen was recovered into storage tank of $NaBH_4$ solution. In this process the condensing water dissolved $NaBH_4$ powder and then addition of $NaBH_4$ solution decreased system weight of 14%. $NaBH_4$ hydrolysis system was stably operated with hydrogen yield of 96% by 2.0g Co-P-B catalyst for 10 hours at 2.0L/min hydrogen evolution rate.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.50-57
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• 1999

The purpose of this study was to determine the thermal inactivation of L. monocytogenes KCTC3443 in liquid culture heated in the controlled microwave system and in the conventional heating method. Furthermore, we have carried out a comparative study on the thermal and nonthermal microwave effects on microorganisms, pasteurized using a controlled microwave energy specially designed apparatuses and a water bath. For the automatic temperature control during microwave heating, the real time data acquisition and computation system is designed with BASIC routine. The automatic temperature control system used in the experiments perform relatively stable control at the experiment temperature of 55, 65, $75^{\circ}C$ and $85^{\circ}C$ for 30 minutes. The effects of microwave heating on liquid cultures was compared with that of conventional heating. The results show that microwave radiation, while being slightly quicker than conventional heating, still reduces effectively the number of pathogenic bacteria during heating for a limit time in liquid cultures. While no particular differences between microwave heating and conventional heating was not observed in the thermal inactivation of L. monocytogenes at 55, 65, $75^{\circ}C$ and $85^{\circ}C$ for 30 min., respectively. Microwave heating is, therefore, substantially not effective in inactivating L. monocytogenes in liquid culture than conventional heating method.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.406-406
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• 2016

To get high efficiency n-type crystalline silicon solar cells, passivation is one of the key factor. Tunnel oxide (SiO2) reduce surface recombination as a passivation layer and it does not constrict the majority carrier flow. In this work, the passivation quality enhanced by different chemical solution such as HNO3, H2SO4:H2O2 and DI-water to make thin tunnel oxide layer on n-type crystalline silicon wafer and changes of characteristics by subsequent annealing process and firing process after phosphorus doped amorphous silicon (a-Si:H) deposition. The tunneling of carrier through oxide layer is checked through I-V measurement when the voltage is from -1 V to 1 V and interface state density also be calculated about $1{\times}1012cm-2eV-1$ using MIS (Metal-Insulator-Semiconductor) structure . Tunnel oxide produced by 68 wt% HNO3 for 5 min on $100^{\circ}C$, H2SO4:H2O2 for 5 min on $100^{\circ}C$ and DI-water for 60 min on $95^{\circ}C$. The oxide layer is measured thickness about 1.4~2.2 nm by spectral ellipsometry (SE) and properties as passivation layer by QSSPC (Quasi-Steady-state Photo Conductance). Tunnel oxide layer is capped with phosphorus doped amorphous silicon on both sides and additional annealing process improve lifetime from $3.25{\mu}s$ to $397{\mu}s$ and implied Voc from 544 mV to 690 mV after P-doped a-Si deposition, respectively. It will be expected that amorphous silicon is changed to poly silicon phase. Furthermore, lifetime and implied Voc were recovered by forming gas annealing (FGA) after firing process from $192{\mu}s$ to $786{\mu}s$. It is shown that the tunnel oxide layer is thermally stable.

• Food Science and Preservation
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• v.11 no.3
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• pp.411-416
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• 2004

Botanical antimicrobial agent-grapefruit seed extract mixture(BAAG), which could be applied to the preparation of antimicrobial packaging paper, was investigated in order to prove the preservative function of fruits and vegetables. HAAG showed remarkable antimicrobial effects against Fusarium solani Botrytis cinerea, Pencillium crustosum, Erwinia carotovora, Phoma destructiva and Alternaria radicina causing the postharvest decay of fruits and vegetables. We have examined that HAAG could inhibit the growth of microorganims when treated with more than 500 $\mu$g/mL concentration. The activities of HAAG were stable in the wide spectrum of pH and temperature. Direct visualization of microbial cells by using scanning electron microscope showed the loss of microbial cell membrane function, which was destroyed by treating with the dilute solutions of HAAG. We could confirm that HAAG be an antimicrobial agent for the preparation of antimicrobial packaging paper.

• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.256-264
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• 2011

By implementing an analysis on the liquid flame proof agent infiltration of microwave-heated wood under soaking conditions (room temperature soaking, heat soaking), its correlation with wood temperature, and the structure of wood and permeating components after soaking in flame proof agent, which was carried out as basic research in order to improve the fire resistance performance of the wood itself, it is found that the infiltration increases as the microwave heating time increases, while for heat soaking, it is found that high infiltration as well as the stable permeability of flame proof agent is achievable. Also, when the wood temperature is more than $80^{\circ}C$, the infiltration by the flame proof agent increased, and a very even infiltration of flame proof agent was observed, which implies that the liquid flame proof agent has a dependency on temperature change of the wood as a condition to penetrate into the wood. As a result of fine structure analysis, the flame proof agent transfer between cells through pits was considered as a cause to increase the infiltration of flame proof agent, and it is also shown that for heat soaking among the permeating component analysis, as the crystallized flame proof agent around the heartwood and sapwood inner pits increases, the flame proof agent can penetrate into the the heartwood part.

• KSBB Journal
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• v.25 no.3
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• pp.289-296
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• 2010

Lectins are carbohydrate-binding and a cell-agglutinating proteins, and are concerted with a plants defence mechanism. In particular, chitin-binding lectins in locular fluid of cherry tomato fruit seemed to have a role in defending plants against fungi. The antifungal activity using lectin isolated from locular fluid of cherry tomato fruit was measured in the plant pathogen Cladosporium cucumerinum, Monosporascus cannonballus, Fusarium oxysporum, and Rhizoctonia solani. Amoung the four strains, a potent antifungal activity was detected in Cladosporium cucumerinum and Monosporascus cannonballus, not in Fusarium oxysporum, and Rhizoctonia solani. The molecular weight of this lectin isolated as double protein bands by SDS-PAGE was calculated to be 87 kDa and 47 kDa from the relative mobilities compared with those of reference molecular weight markers. The isolated lectin agglutinated human red blood cells (A, B, AB, O) treated with trypsin, and the most activity was found at B. The optimal temperature of isolated lectin was at $30^{\circ}C$. For the thermal stability, lectin was stable at $20-80^{\circ}C$. The optimal pH of this lectin was at 7.2, and showed complete loss below pH 9.0.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.252-258
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• 1991

With HMPAO we have synthesized in our laboratory, we labelled $^{99m}Tc$ to canine leukocytes. Experimental abscess made by subcutaneous injection with Staphylococcus aureus was imaged with these $^{99m}Tc$ labelled leukocytes. Labelling efficiency of HMPAO with $^{99m}Tc$ was $66.2%{\pm}14.6%$ (N=9). Labelling efficiency of leukocytes with $^{99m}Tc-HMPAO$ was $54%{\pm}7.7%$ (N=7). Cell bound radioactivity in $^{99m}Tc-HMPAO$ labelled leukocytes was around 80% when these cells were incubated in plasma in vitro at $37^{\circ}C$ for 5 hours. In vivo cell bound activity was over 80% at 24 hours after injection. One day and four days after inoculation, uptake at the inflammatory focus was found with $^{99m}Tc$ labelled leukocytes. Uptake showed up in 4 hour image, and the uptake at the lesion was most prominent in 24 hour image. These findings show that in-house-synthesized HMPAO could be used for labelling leukocytes with $^{99m}Tc$, and that s$^{99m}Tc-HMPAO-labelled$ leukocytes were so stable and viable that inflammatory focus could be visualized with these $^{99m}Tc-labelled$ leukocytes.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2001.10a
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• pp.37-43
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• 2001

1. About fifty thousand of cattle embryos were transferred and 16000 ET-calves were born in 1999. Eighty percents of embryos were collected from Japanese Black beef donors and transferred to dairy Holstein heifers and cows. Since 1985, we have achieved in bovine in vitro fertilization using immature oocytes collected from ovaries of slaughterhouse. Now over 8000 embryos fertilized by Japanese Black bull, as Kitaguni 7~8 or Mitsufuku, famousbulls as high marbling score of progeny tests were sold to dairy farmers and transferred to their dairy cattle every year. 2. Embryo splitting for identical twins is demonstrated an useful tool to supply a bull for semen collection and a steer for beef performance test. According to the data of Dr. Hashiyada(2001), 296 pairs of split-half embryos were transferred to recipients and 98 gave births of 112 calves (23 pairs of identical twins and 66 singletons). 3. A blastomere-nuclear-transferred cloned calf was born in 1990 by a joint research with Drs. Tsunoda, National Institute of Animal Industry (NIAI) and Ushijima, Chiba Prefectural Farm Animal Center. The fruits of this technology were applied to the production of a calf from a cell of long-term-cultured inner cell mass (1988, Itoh et al, ZEN-NOH Central Research Institute for Feed and Livestock) and a cloned calf from three-successive-cloning (1997, Tsunoda et al.). According to the survey of MAFF of Japan, over 500 calves were born until this year and a glaf of them were already brought to the market for beef. 4. After the report of "Dolly", in February 1997, the first somatic cell clone female calves were born in July 1998 as the fruits of the joint research organized by Dr. Tsunoda in Kinki University (Kato et al, 2000). The male calves were born in August and September 1998 by the collaboration with NIAI and Kagoshima Prefecture. Then 244 calves, four pigs and a kid of goat were now born in 36 institutes of Japan. 5. Somatic cell cloning in farm animal production will bring us as effective reproductive method of elite-dairy- cows, super-cows and excellent bulls. The effect of making copy farm animal is also related to the reservation of genetic resources and re-creation of a male bull from a castrated steer of excellent marbling beef. Cloning of genetically modified animals is most promising to making pig organs transplant to people and providing protein drugs in milk of pig, goat and cattle. 6. Farm animal cloning is one of the most dreamful technologies of 21th century. It is necessary to develop this technology more efficient and stable as realistic technology of the farm animal production. We are making researches related to the best condition of donor cells for high productivity of cloning, genetic analysis of cloned animals, growth and performance abilities of clone cattle and pathological and genetical analysis of high rates of abortion and stillbirth of clone calves (about 30% of periparutum mortality). 7. It is requested in the report of Ministry of Health, labor and Welfare to make clear that carbon-copy cattle(somatic cell clone cattle) are safe and heathy for a commercial market since the somatic cell cloning is a completely new technology. Fattened beef steers (well-proved normal growth) and milking cows(shown a good fertility) are now provided for the assessment of food safety.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.221-228
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• 2001

This study was carried out to investigate the effect of germination condition and drying temperature on growth and physicochemical properties of brown rice. Three brown rice seeds of Ilpumbyeo, Dasanbyeo and Heugjinjubyeo were stored at room temperature for six weeks to test the time-sequence germination viability. Relatively stable germination ratio was maintained until 2 weeks after storage. However, 3 weeks after storage, germination ratio of brown rice seeds started to decrease rapidly and their germination ratio was lower than 80%. For this reason, brown rice was recommended for seeding within 2 weeks after hulling. During the initial 5 days, germination ratio of 24 hours pre-soaking brown rice was higher about 2-3% than that of non-soaking brown rice. The $25^{\circ}C$ was considered as the most favorable temperature for brown rice germination, because of the high germination ratio and desirable coleoptile growth of the brown rice, and little seed rotting symptoms. The scanning electron micrographs showed the structural differences between hot-air dried and freeze dried germinated-brown rice kernel. In the freeze dried germinated-brown rice, seed coat (pericarp, tegmen and aleurone layer) was mechanically disrupted from the endosperm, and many cleavages were observed among starch storing cells and starch granules. The endosperm of freeze-dried brown rice kernels formed the sponge-like structures and showed the fragile traits. For this reason, hot-air drying is considered as more suitable method than freeze drying for germinated-brown rice. The crude protein and amylose contents were slightly changed, but there were no significant differences during the germination period. Crude fiber content was decreased, but crude Int and total amino acid contents were increased as seeding days increased. A rapid increase in $\alpha$-amylase activities of germinating brown rice was observed at S days after seeding, and $\alpha$-amylase activities were decreased from 8 days after seeding. Total free sugar contents were decreased during the germination period. There was continuous decline in the contents of sucrose and glucose until 8 days after seeding, but fructose and maltose content were gradually increased from the 5 days after seeding.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.74-80
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• 2011

Bacteriocin-producing lactic acid bacterium having antagonistic activity against Bacillus cereus, was isolated from Kimchi. The selected strain was identified as Lactococcus lactis by the Bergey's manual and 16S rDNA analysis, and named as L. lactis ET45. The bacteriocin was stable in the pH range 3.0-11.0. The bacteriocin was active over a wide temperature range from $40^{\circ}C$ to $121^{\circ}C$. Optimal culture condition for producing bacteriocin was obtained by growing the cells on MRS medium at pH 7.5 and $30^{\circ}C$ for 18 h. Antibacterial activity of the bacteriocin was completely disappeared by proteinase K, and this means that bacteriocin is a proteinous substance. The molecular weight of bacteriocin was estimated to be about 4.5 kDa by tricine sodium dodecyl sulfate polyacryamide gel electrophoresis (TSDS-PAGE).