• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.110-117
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• 1998

A packed-bed reactor with immobilized transglucosidase (TG) was operated to test the possibility of continuous production of isomaltooligosaccharides (IMO) and the effect of concentration and feed rate of substrate solution on the production pattern as well as operational stability The pattern of formation of IMO was the same to the one of soluble TG. The concentrations of glucose and isomaltose produced by the packed-bed reactor were gradually decreased as the flow rates were increased regardless of the concentrations and kinds of maltose solution as substrate. Isomaltotriose showed the same tendency except 10% maltose solution. But the concentration of panose was increased and then decreased as the flow rates were increased. The maximum yield of IMO was 52.1% when 10% (w/v) solution was fed to the reactor at 2 mL./min feed rate. When each 20% and 30% (w/v) solution was respectively used at $0.5{\sim}1.0\;mL/min$, the maximum yield were $39.0{\sim}38.0%\;and\;12.1{\sim}14.2%$. The maximum yield was 36.3% at $0.5{\sim}1.0\;mL/min$ when a commercial maltose product containing 20% maltose was used. The reactor was stably operated at $55^{\circ}C$. 85% and 65% of initial activity was maintained for 144 hours and 288 hours of operation, respectively. A reactor analysis strongly an immobilized TG system could apply to continuous production of IMO.

• KSBB Journal
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• v.16 no.1
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• pp.24-29
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• 2001

Recently hepatocyte-based bioartificial liver (BAL) and hepatocyte transplantation have been actively investigated to treat acute hepatic failure. The BAL acts as a bridge to provide patients with more time until a donor organ becomes available for transplantation or until their own liver can be regenerated. In this study, we manufactured a polyurethane foam (PUF) using 15% NCO-prepolymer with a pore opening that allows it to be used as a hepatocyte immobilizing material. Cubes of PUF (3 mm dim.) were seeded with rat primary hepatocytes at a density of 5.5$\pm$1.1$\times$ $10^6$ cells/$cm^3$ PUF by centrifuging them together. The cell laden PUF cubes were packed into a prototype reactor and perfused with a hormonally defined medium for a week. Hepatocytes in the pores of the PUF formed spheroids that showed stable ammonia removal and urea synthesis activities. The albumin production level was comparable to other BAL systems. The PUF packed hepatocyte bioreactor has the potential to be used as a BAL.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.271-273
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• 2003

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.289-292
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• 2002

전분을 이용한 환경친화성 고분자 플라스틱 재료에는 전분충진형, blend형 등이 있으나, 대체로 전분은 보조재료로 사용된다. 이에 반해 extruder를 이용한 전분발포체나 TPS (Thermoplastic starch) 등은 전분을 주재료로 사용하여 플라스틱 재료를 만드는 것이지만, TPS 필름의 Tg가 실온보다 높아 glassy 상태의 brittle한 성질로 인해 물성이 낮으며, 수분 친화적인 성질로 인해 플라스틱 재료로서의 사용이 제한되는 단점이 있다[1,2]. (중략)

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.222-229
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• 2006

Recently, the development of the paved track is required as a low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The important factors of paved track are stability and applicability. To be based on this subject, Cement Mortar Pouring(CMP) paved track is developed. CMP paved track is a kind of ballast reinforced track using the prepacked concrete technique. The most important thing to design the paved track is to optimize the track structure considering various conditions. Because construction environment is very limited, cost is expensive and it has very complicated behavior. On this paper, structural characteristics of the paved track are investigated using the 3D finite element analysis to verify the optimized structure of the CMP track.

• Journal of the Korean Society for Railway
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• v.9 no.3 s.34
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• pp.305-312
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• 2006

Gravel ballasted tracks are used as a basic structure for the domestic railway tracks. However, such kind of tracks has few disadvantages with service life of the structure, such as rapid deterioration of the tracks. Due to this reason, there is a need to develop low maintenance track to improve the service life of the conventional line tracks. CMP paved tacks are one of the kind of concrete tracks those were manufactured by using the prepacked concrete techniques. The purpose to develop paved tracks is to reduce the maintenance cost. The most important controlling factors to design the paved tracks are surrounding environmental condition and repeated train loading. In this study, in order to investigate the deformation characteristics such as displacement, earth pressure, strain ratio, and crack along the repeated loading cycle, cyclic loading test through real scale model was carried out.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.331-338
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• 2015

Solar air heaters (SAHs) are simple in design and widely used for solar energy collection devices, and a packed bed is one of typical solar energy storage systems of thermal energy captured by SAHs. This paper presents mathematical modeling and simulation on the thermal performance of various packed bed energy storage systems. A MATLAB program is used to estimate the thermal efficiency of packed bed SAH. Among the various packed bed energy storage systems considered, the wire mesh screen packed bed SAH shows the best thermal efficiency over the entire range of design conditions. The maximum of thermal efficiency of packed bed SAH with wire mesh screen matrices has been found to be 0.794 for Re=2000 - 20000 and ${\Delta}T/I=0.002-0.02$.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.836-841
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• 2004

Recently, the development of the paved track is required as a Low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The most important factor of paved track is stability and applicability. To be based on this subject, Cement Mortar Pouring(CMP) paved track is developed. CMP paved track is a kind of ballast reinforced track using the pre packed concrete technique. The most important to design is characteristics of the structure. CMP slab's thickness is less than the conventional slab track and pouring layer is attached tie and roadbed directly. On this paper, to verify the basic structure of the CMP track, characteristics of the structure is investigated pouring layer, tie and interaction of the each layer using the 3D finite elment analysis.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.389-393
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• 2005

When the high-speed train running on the track, there is a speed limit which track distortion is unusually increased according to condition of track and roadbed. This speed limit is called critical velocity, and physical parameter value increased very greatly. These phenomenon happened as high-speed train were developed, studied regularly through TGV 100 running test in France. As research result until now, the main reason is soft roadbed's capacity. Wave propagation and track support capacity is varied by the site characteristics. This paper achieved theoretical examination about resonance band(speed and frequency) that occurred in roadbed on the base rock in point of geotechnical engineering. The examination of resonance divides with ground response analysis, critical band analysis by the shear wave velocity of roadbed, train critical speed through the ground stratum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.57-64
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• 2017

Today, due to the environmental regulations regarding air pollution in the EU, the use of EPS (Styrofoam) as the cushioning material in the packaging industry is decreasing. In effect, air cushioning based cushioning materials are rapidly expanding into the market and replacing EPS, due to their excellent buffering ability and environmental friendliness. This is a new selective filling type air filling material manufacturing technology that affords improvements in the amount of raw materials required, its processing and its aesthetic appearance compared to the conventional air filling cushioning materials. In this study, a multi-stage air cell filling valve molding technology is developed based on selective filling technology, which allows packages to be selectively filled in various forms by applying valve forming structure technology. This multi-stage air cell filling valve molding technology is a technique in which a plurality of injection ports are formed by laminating three layers of films, viz. a first injection film, a valve film, and a second injection film having valve ends. In the conventional technology, a separate external air injection path for injecting air into a plurality of connected air bags is needed. However, in the proposed system, an external air injection path is formed inside the air bag, Due to the lack of need for an injection furnace, the raw material and process are reduced and air is injected and then discharged, while the air bag is reduced in length to 63 ~ 66% of its normal value. The outer surface of the outer air injection path is integrated inside by maintaining the original length of the cross section, while the unnecessary folded air is injected into the interior of the air bag, This smart air filling type cushioning material manufacturing technology constitutes a big improvement over the existing technologies.