• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.11
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• pp.643-648
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• 2009

Tests were conducted to obtain heat transfer coefficients during slush formation from 10% sucrose solution. The slush was made by scraping the ice formed on the cylinder. Cold brine was supplied inside of the evaporator cylinder to cool the outer surface. Below a certain brine temperature, which was $-5^{\circ}C$ in this study, the solution was supercooled, and suddenly turned into ice crystals. During slush formation, the heat transfer coefficient oscillated significantly, due to periodic removal of ice chunk form the surface. The average heat transfer coefficient during slush formation was 40~70% higher than that obtained during single phase cooling. The heat transfer coefficient was also affected by the brine temperature with increasing heat transfer coefficient at higher brine temperature.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.1
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• pp.1-7
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• 2009

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.346-350
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• 2008

Tests were conducted to obtain heat transfer coefficients during slush formation from 10% sucrose solution. The slush was made by scraping the ice formed on the cylinder. Cold brine was supplied inside of the cylinder to cool the outer surface. Below a certain brine temperature, which was $5^{\circ}C$ in this study, the solution was supercooled, and suddenly turned into ice. The super-cooling increases as the brine temperature increased. During slush formation, the heat transfer coefficient oscillated significantly, due to periodic removal of ice chunk form the surface. The average heat transfer coefficient during slush formation was approximately twice of that obtained during single phase cooling. The heat transfer coefficient was also affected by the brine temperature with increasing heat transfer coefficient at lower brine temperature.

• Proceedings of the SAREK Conference
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• 2006.11a
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• pp.94-94
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• 2006

• Clinical and Experimental Reproductive Medicine
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• v.37 no.4
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• pp.307-319
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• 2010

Objective: Vitrification requires a high concentration of cyroprotectant (CPA) and an elevated cooling speed to avoid ice crystal formation. We have evaluated the effect of different combinations of cooling rate and CPA on embryonic integrity (developmental competence) in order to increase the efficiency of vitrification without impairing embryo viabilit. We hypothesized that the combination of CPA or the increase of cooling rates can reduce the concentration of toxic CPA for vitrification. As consequently, we performed experiments to evaluate the effect of various composition of CPA or slush nitrogen ($SN_2$) on the mouse embryonic development following vitrification using low CPA concentration. Methods: Vitrification of mouse embryos was performed with EM grid using liquid nitrogen ($LN_2$) or $SN_2$ and different composition of CPAs, ethylene glycol (EG) and dimethylsulfoxide (DMSO). After vitrification-warming process, their survival and blastocyst formation rates were examined. For analyzing long-term effect, these blastocysts were transferred into the uterus of foster mothers. Results: Survival and blastocyst formation rates of vitrified embryos were higher in EG+DMSO group than those in EG only. Furthermor, the group using $SN_2$ with a lower CPA concentration showed a higher survival of embryos and developmental rates than group using $LN_2$. Conclusion: The combination of EG and DMSO as CPAs may enhance the survival of mouse embryos and further embryonic development after vitrification. $SN_2$ can generate high survival and developmental rate of vitrified/warmed mouse embryos when a lower concentration of CPA was applied. Therefore, these systems may contribute in the improvement of cryopreservation for fertility preservation.

• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.51-56
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• 1999

This research was carried out to investigate the Hanji sludge(black color)-wood fiber and wood particle composited applied by waste sludges arising from the making process of Hanji (Korea paper). In experimental design, four levels of the mixed ratio of Hanji sludge to wood fiber or wood particle(10:90, 20:80, 30:70 and 40:60), three kinds of the resin(PMDI, urea and phenol resin)and three kinds of the specific gravity(0.6, 0.75 and 0.9) were designed to determine the tensile strength of Hanji sludge-wood fiber and wood particle composites. From the results and discussion, it may be concluded as follows: In Hanji sludge-wood fiber and wood particle composites, tensile strengths showed decreasing tendency absolutely by increasing Hanji sludge additive, but clearly increase with the increase of specific gravity. In Hanji sludge-wood fiber composites, there were no differences between PMDI and urea resin-bonded composites, but phenol resin-boned composites were made possibly until the addition of 30% Hanji sludge. On the other hand, Hnji sludge-wood particle composites(SpGr=0.6) have very low tensile strength values. But they were made favorably until the addition of 20% Hanji sludge in Hanji sludge-wood particle composites(SpGr=0.9).

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.327-333
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• 1995

The sludge application increased the panicle number per plant and number of spikelets per panicle, resulting in an increase in yield by 10% at Cheongdo, 15% at Chinju and 7% at Yeocheon. With the sludge application (3% w/w), $SiO_2$ content of brown rice was significantly increased. The sludge aplied up to 34.8 ton per hectare increased pH, calcium, and potassium in paddy soils, the application of the sludge to reclaimed saline soil at Yeocheon needs to be reevaluated since the sludge increased soil pH to 7.2 and aggravated drainage.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.351-354
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• 2002

This research discussed about the substrate transport phenomena in anaerobic biofilm. Three anaerobic fixed biofilm reactors were filled with the sludge of anaerobic digestor from Suyoung wastewater treatment plant. After 15 days of biofilm formation periods, suspended solids within the reactors were removed, and each fixed biofilm reactor was supplied with synthetic wastewater of different concentration of 8.00 mgTOC/L, 9.76 mgTOC/L and 18.97 mgTOC/L, respectively. The experimental results in conjunction with substrate transfer phenomena indicated that data - thickness, substrate removal rate. At the low influent substrate concentration(reactor 1 : 8.00 mgTOC/L, reactor 2 : 9.76 mgTOC/L), the rate of substrate utilization($k_v$), effective diffusivity($D_{eff}$) of substrate in biofilm were similar. While $k_v$ and $D_{eff}$ of the high influent substrate concentration(reactor 3 : 18.97 mgTOC/L) were higher than data in the reactors of the low influent substrate concentration.

• Vending industry
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• v.10 no.1
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• pp.66-68
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• 2010

자동판매기 시장의 부진은 사업 아이템에 대한 심각한 고민을 수반하기 마련이다. 정통 자판기가 부진을 보이는 상황에서 그래도 유관아이템을 찾아 사업 다각화를 꾀해가는 것도 난세를 생존해 가는 비결이다. 이런 측면에서 최근 식품영업용기기에 대한 관심이 높아지고 있다, 식품영업용기기란 자동판매기처럼 완전자동은 아니지만 반자동형태로 기계를 통해 사람이 조리 식품을 만들어주는 기계이다. 기계를 통해 간편하게 만들 수 있다는 측면에서는 자판기 시스템에 해당된다고 할 수 있고, 사람이 재료를 넣고 반자동으로 이용한다는 점에서 자판기와 차이가 있다. 예를 들어 슬러시, 소프트아이스크림기, 팝콘자동기, 솜사탕제조기, 와플기기, 뻥튀기기기 등의 품목을 들 수 있다. 이들 아이템은 자판기에 비해 상대적으로 적은 비용을 투자해 '샵 인 샵' 형태로 영업을 진행하며 수익을 강화할 수 있다는 장점이 있다. 최근 자판기 시장은 부진한 반면 상대적으로 식품영업용기기 시장이 늘고 있다는 사실은 주목해야 할 부분이다. 반자동이라고 해도투자부담이 낮고, 실용적인 아이템에 대한 가치가 상승하고 있는 것이다. 일반식품자판기 분야를 놓고 보면 식품영업용기기기가 경쟁자이자 상호 공생의 관계에 있다 할 수 있다. 일반식품자판기의 상품화 방향에 있어 식품영업용기기의 실용적인 장점은 취하고, 반자동의 한계를 보완한다면 시장성이 지금보다는 좋아 질 수 있을 것이다. 이런 점에서 볼 때 식품영업용기기 시장 추이에도 관심을 가져야 한다. 그런데 식품영업용기기도 주기적인 트렌드에 의해 인기를 끄는 제품이 달라진다. 지난해에는 와플기와 팝콘자동기가 인기를 끌었었다. 와플기는 간단하게 간식거리를 만들어 제공할 수 있다는 점에서 '샵 인 샵' 아이템으로 인기를 모았다. 이러한 동향 탓에 와플기의 시장경쟁도 치열해 지고, 좀 더 새로운 제품에 대한 니즈 역시 커지고 있다. 이번에 소개할 다원푸드의 웰빙 찰보리 와플기는 기존 와플기와는 재료와 방식에 있어 완전 차별화를 한 제품이다. 건강지향의 니즈에 맞게 찰보리를 재료로 했고, 와플형태도 스틱방식으로 마든 제품도 있어 먹기에도 편하게 했다. 과연 이 찰보리 와플기가 와플시장의 새로운 돌풍을 일으킬 수 있을까?

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.6
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• pp.565-572
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• 2021

Hydrogen is currently produced from natural gas reforming or industrial process of by-product over than 90%. Additionally, there are green hydrogens based on renewable energy generation, but the import of green hydrogen from other countries is being considered due to the output variability depending on the weather and climate. Due to low density of hydrogen, it is difficult to storage and import hydrogen of large capacity. For improving low density issue of hydrogen, the gaseous hydrogen is liquefied and stored in cryogenic tank. Density of hydrogen increase from 0.081 kg/m³ to 71 kg/m3 when gaseous hydrogen transfer to liquid hydrogen. Density of liquid hydrogen is higher about 800 times than gaseous. However, since density and boiling point of liquid hydrogen is too lower than liquefied natural gas approximately 1/6 and 90 K, to store liquid hydrogen for long-term is very difficult too. To overcome this weakness, this paper introduces storage method of hydrogen based on liquid/solid (slush) and facilities for producing slush hydrogen to improve low density issue of hydrogen. Slush hydrogen is higher density and heat capacity than liquid hydrogen, can be expected to improve these issues.