• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.82-82
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• 2019

종자은행은 종자를 보존하는 가장 경제적이고 효율적인 보전방법이지만, 수종에 따라 저장특성의 차이가 커서 수종별 저장방법의 확립이 필요하다. 초저온저장 방법은 세포 분열, 대사 작용을 정지 상태로 유지하므로 현재까지 장기간 보존을 위한 비용이 효율적이며 안정적인 방법이다. 공시재료는 멸종위기 야생식물 등 22종을 대상으로 하였다. 액체질소에 7일간 종자를 침지한 후 $37^{\circ}C$ 항온수조에서 10분간 해동하였다. 휴면이 있는 수종은 파종 전 종자를 저온습윤 하였고, 저온습윤 처리 후에도 휴면타파 되지 않는 수종은 농황산, 지베렐린을 개별 또는 혼용으로 처리하였다. 발아 및 유묘 평가는 $25^{\circ}C/20^{\circ}C$(광12h/암12h)조건에서 진행하였으며, 매일 28일차까지 발아조사를 수행한 후 평가하였다. 진달래속의 꼬리진달래와 철쭉이 초저온 민감성을 보였으며, 오리나무속의 물오리나무, 사방오리는 부분 민감성을 보였다. 민산초나무는 지하부건물중이 유의하게 감소한 결과를 보였으며, 이외의 수종은 초저온 민감성을 보이지 않았으므로 장기보존을 위한 초저온 동결보존이 가능한 것으로 보였다.

• Korean Journal of Plant Resources
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• v.14 no.3
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• pp.251-258
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• 2001

Predehydration effects for cryopreservation in -196$^{\circ}C$ liquid nitrogen were studied in Korean native Aquilegia buergeriana var. oxysepala Kitamura and A. flabellata var. pumila Kudo seeds. Aquilegia species seeds were adjusted to moisture contents between 3.2 and 9.7% by air dry treatments. Seeds were placed in paper envelopes after submerged in liquid nitrogen and rewarming in 38 $^{\circ}C$ water. Seeds moisture contents by duration of drying were identified as controlling factors in the survival of Aquilegia species seeds for cryopreservation. Aquilegia species seeds having approximate 5% moisture content were able to withstand cooling to -l96$^{\circ}C$. Undehydrated seeds of Aquilegia buergeriana var. oxysepala Kitamura after being cryopreservated in liquid nitrogen have a 10.9% of moisture content and show 52.5% in germination. But, Aquilegia buergeriana var. oxysepala Kitamura seeds dehydrated by drying for 60 min. to have 6.0% of moisture content before cryopreservation show 84.7% in germination test. Properly dehydrated seeds after being stored in liquid nitrogen showed over 60% in germination rate and also shows an uniform sprouting time,11~13 days in average. Any morphologically deformity in germinating beds has not been observed. Results from this study suggest that Aquilegia species seeds can cryopreservation in liquid nitrogen if the seed moisture content is controled by a proper amount of dehydration.

• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.37-48
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• 1998

A cryogenic liquid stored in the closed cryogenic tank has been studied at various liquid levels. The change of pressure, temperature, and liquid-vapor ratio in the tank depended on the liquid levels. The various phenomena were shown at different liquid levels as follows: (1) liquid level was increased with condensation of vapor: (2) liquid was vaporized in spite of liquid level going up for a certain initial period and then condensation of vapor occurred at higher pressure; (3) liquid was vaporized without liquid level change; (4) liquid was vaporized with liquid level decreasing. If the tank is full with cryogenic liquid, it is extremely dangerous because of soaring the pressure. Therefore the tank must be filled with $90\%$ liquid according to the safety rules. If the tank was filled with $0\%$ ullage, the pressure increment as high as 80bar during first 5 days. With $90\%$ liquid level, however, the pressure was increased as low as 1.5bar in the same period. No matter what the liquid level is, it is very dangerous if the tank is locked-up with filled cryogenic liquid for a long time.

• Food Science and Preservation
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• v.10 no.3
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• pp.411-416
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• 2003

An effort was attempted to utilize an under-utilized protein source, rice bran protein, in coating or wrapping food material for the purpose of protection them from oxidation and bacterial infection. However, the utilization of rice bran protein as a food coating material is limited because the rice bran protein coating material itself can be spoiled by a bacterial infection. Therefore, this study was conducted to produce the economical and antibacterial rice bran protein film by utilizing rice bran and bacteriocin-producing microorganism. Bacteriocin produced by Pseudomonas putida 21025 was partially purified after 33h of shaking incubation at 30$^{\circ}C$. The amount of amino-type nitrogen did not increase in the rice bran protein film containing the bacteriocin any more after gradual increase upto the content of 0.22％ for 8 days, while that without the bacteriocin increased continuously, implying that application of the bacteriocin to the rice bran had positive effects on prolonging the shelf-life of not only film itself but also the foods wrapped by this film.

• 전기의세계
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• v.53 no.8
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• pp.39-42
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• 2004

초전도 재료는 선재의 형태로 가공하면 송전선이나, 변압기, 발전기 및 전력 저장장치와 같이 전력 응용의 효율을 극대화시킬 수 있는 재료로서 널리 활용되고 있다. 1987년 개발된 고온 산화물 초전도체는 액체질소 의 비등점인 77K 이상에서 초전도 현상을 나타내어 초전도 현상의 응용에 대한 기대를 고조시켜 이에 대한 연구 개발을 더욱 향상시키고 있다. 초전도 선재에 관한 연구는 주로 PIT( Powder in Tube )공정을 이용한 Ag/Bi 2223 선재가 우수한 전기적 특성과 가공의 우수성으로 인하여 개발되어 왔다. 그러나 Ag/Bi 2223 선재는 강한 자기장 하에서 통전 특성이 현저하게 저하되는 결점이 있다. (중략)

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.802-808
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• 2011

One of the important mechanical properties of cryogenic temperature structure material is fracture toughness. Research on normalization of fracture toughness test method is becoming very important issue with development of cryogenic structural elements. Specially, mechanical properties estimation by each micro-structure of welding department is important because it can cause unstable fracture when use under cryogenic environment in case of welding department. In this study, fracture toughness estimation test was carried out to unloading compliance method and sensitization heat-tread minimized test specimen at liquid nitrogen (77K), liquid helium (4K), 293K temperature to STS-316L base metal and weld metal.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.19-27
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• 1996

Self-pressurization of cylindrical container of cryogen is numerically analyzed. The container is axi-symmetric and heated from side wall with constant heat flux. Natural convection by external heat flux is studied numerically using finite difference method. Oxygen, nytrogen and hydrogen are working fluids in this paper. Liquid is considered incompressible fluid and vapor is assumed to behave as gas meeting with virial equation of gas. The Second virial coefficients of gas are obtained from Lennard-jones model. The important variables which have effects on self-pressurization are external heat flux, heat capacity of wall and initial ullage in container. The most important variable of them is external heat flux. The pressure rise calculated from the virial gas model is slightly different from that calculated using Ideal gas model for oxygen.

• Food Science and Preservation
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• v.11 no.1
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• pp.111-116
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• 2004

The optimum cultural conditions for production of red pigment from Monascus rubber KCTC 6122 is liquid culture were studied. Monascus robber KCTC 6122 was shown to give the maximum production of red pigment in the medium containing 4％ rice powder, 0.2％ NaNO$_3$, 0.3％ Na$_2$HP0$_4$ and 0.15％ MgSO$_4$. The optimum culture conditions, temperature, initial pH and shaking speed were 30$^{\circ}C$, 6.5 and 150 rpm, respectively. The red pigment production reached a maximum level at 8days of cultivation.

• Korean Journal of Medicinal Crop Science
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• v.7 no.1
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• pp.1-6
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• 1999

Basic informations for direct somatic embryo formation in Rehmannja glutinosa Lib. were obtained in 500ml erlenmyer flask. The ratio of ammonium to nitrate nitrogen of 825(mg/l) : 1900(mg/l) was proper condition for somatic embryo formation from stem and petiole explants and 3% sucrose was the most effective carbon source. Full strength MS medium with 2mg/l BA was better than LS medium for somatic embryogenesis. The initial pH 5.7 of medium(full strength MS with 2.0mg/l BA and 0.1mg/l NAA) was good for embryo production. Potassium ion was taken up rapidly within 2 weeks. while $Ca^{++}$ and $Mg^{++}$ ion contents were almost constant during culture period. Sucrose hydrolysis occurred throughout the culture, while glucose and fructose were absorbed simultaneously from the third week of culture.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.131-136
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• 2008

The double-walled steel vessel with powder insulation in the space between the walls is used to minimize heat transfer by radiation and conduction in cryogenic storage tank. The vacuum required the insulation is much less extreme than with high-vacuum or multilayer insulations. The solid supports are used to bear the weight of the inner container. Thermal and structural analysis of the tank have been carried out to study the effect of vacuum and weldment geometry of the internal supports. Heat flux in wall is increased with increasing of thermal conductivity of perlite. Heat flux and stress of support is not affected by weldment geometry.