• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.115-121
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• 1999

Changes of free sugars, lipoxygenase activity and effects of chitosan treatment were analyzed during cultivation of soybean sprout. Free sugars(sucrose, raffinose and stachyose) were more rapidly decomposed in the cotyledon of soybean sprout. Contents of sucrose and raffinose in control group were decreased more rapidly than those of chitosan treated soybean sprouts (CTSS). But the decreasing rate of stachyose was higher in the CTSS. In the hypocotyl, 82% of L-2/3 activity were decreased, whereas 42% of the activity were decreased in the cotyledon after 132 hours of germination. The effect of chitosan treatment on the lipoxygenase activity was more effective on L-2/3 isozyme than L-1. After the germination period of 132 hours, L-2/3 activity of control group was 82.7unit/mg and that of CTSS was 56unit/mg.

• Membrane Journal
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• v.14 no.2
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• pp.149-156
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• 2004

This work focused on the degradation of natural organic matter (NOM) present in lake water using a combined pkotocatalysisimicrofiltration (MF) process. The system performances were investigated in terms of organic removal efficiency and membrane permeability. The addition of iron oxide particles (IOP) into the photocatalytic membrane reactor improved initial NOM removal by sorption, but during photocatalysis the removal efficiency was reversed, probably due to the scattering of UV light by IOP. The modification of TiO$_2$ surfaces by IOP deposition was conducted to enhance the photocatalytic NOM removal efficiency. A minimal amount of Impregnation of IOP on TiO$_2$ surfaces was required to prevent the light scattering effect as well. The coating of MF membranes with IOP helped to improve the NOM removal efficiency while sorbing NOM by IOP. Regardless of tile operating conditions and particles addition examined, no significant fouling was occurring at a flux of 15 L/$m^2$-h during entire MF operation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.395-402
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• 2017

Recently, many researches on crack healing and repairing technique using bacteria which can produce vital-reacted calcite have been proposed. This study is for a basic research on repair material with slime formation through bacteria and deals with durability evaluation for coating materials containing bacteria-forming slime. For the work, 4 types of bacteria (Rhodobacter capsulatus, Rhodopseudomonas palustris, Bacillus thuringiensis, and Bacillus subtilis) and 2 types of nutrient conditions are considered, and several tests covering strength evaluation under sulfate condition, accelerated chloride diffusion, and UV (Ultrasonic Velocity) measurement are performed. Strength improvement in coating materials containing bacteria is evaluated in spite of even exposure to sulfate attack to 7 days. Chloride diffusion coefficient and UV properties are also improved except for the case of Rhodopseudomonas palustris. With resistance of slime to long term exposure and aerobic conditions for bacteria longevity, the proposed bacteria shows an engineering feasibility for repair material of RC structure exposed harsh environment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1529-1540
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• 1993

The quenching of steels by water is one of the imprtant problems in the applications of heat treatment, but the fundamental researches by way of theoretical approaches have not been satisfactorily improbed yet. This study aimed at measuring the exact subcooled transient boiling curve for cylindrical specimens and at conducting the analytical researches into the prediction of cooling curves, including the latent heat of phase transformation of steel. Experiments of quenching were made with cylindrical specimens of carbon steel S45C of diameters from 12 to 30 mm and with Cu specimens of 12 mm diameter respectively. The internal temperature of specimens during the quenching process was measured by C-A sheathed thermocouple. The heat fluxes were numerically calculated by the numerical method of inverse heat conduction problem, using the measured inner temperature of specimen as a boundary condition. In case of ${\Delta}T_{sub}=80K$, $q_{s}$ is as follows $q_{s}=2.02{\times}10^{5}{\Delta}T_{set}^{0.05}:{\Delta}T_{set}\le500K.$ And the numerical analysis of unsteady heat conduction during the quenching process was made and the cooling curves were calculated by TDMA method.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.842-845
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• 2002

Physicochemical properties and water uptake rate of pigmented rice were determined. The median and mean particle sizes of pigmented rice flour were 15.18 and $38.53\;{\mu}m$, whereas brown rice flour were 11.46 and $33.41\;{\mu}m$, respectively. Water-binding capacity, swelling power, and solubility of pigmented rice flour were higher than those of brown rice flour. X-ray diffraction patterns showed traditional A type of cereals. Moisture gain of pigmented rice kernels increased continuously up to 60 min at soaking temperature $(20{\sim}25^{\circ}C)$. Water uptake rate constants of pigmented rice during soaking at $20{\sim}25^{\circ}C$ also increased.

• Food Science and Preservation
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• v.7 no.4
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• pp.403-408
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• 2000

To enlarge applicable field of electrolyzed acid-water(EAW) on food industry, quality changes of agaricus mushroom(Agaricus blazei Mui1l) washed with cooled EAW were investigated during storage at 5$\^{C}$. Total count and coliform count were decreased to 1/88 level and l0$^1$cfu/g respectively by immersion washing with EAW for 5 min. Agaricus mushroom washed with EAW had showed better quality properties such as weight loss, pH, acidity, browning, organoleptic properties after 3∼4 days of storage at 5$\^{C}$ except firmness of the trunk parts of agaricus mushroom comparing with non-treated one. △E values of agaricus mushroom showed lower increasement than those of non-treated ones after 3∼4 days of storage. Considering organoletpic and quality characteristics of stored agaricus mushroom synthetically, it was showed that EAW could be applicable to shelf life extension of argaricus mushroom.

• Elastomers and Composites
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• v.45 no.1
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• pp.40-43
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• 2010

In this study, polyimide(PI) nanofibers mats were prepared by electrospinning and three different fiber morphologies of random, uniaxial, and biaxial orientation were prepared by controlling the speed of drum-shaped collector and other parameters. The SEM studies reveal that the aforesaid morphologies were obtained on the nano-fibrous mats prepared. The ionic conductivity was measured using an in-plane type conductivity tester for the PI mats soaked in the mixture of 1M lithium trifluoro-methane-sulfonate and tetra-ethylene glycol dimethyl ether. The ionic conductivity was surprisingly higher for the biaxial PI mats. For the uniaxially-oriented mats, the ionic conductivity was found to be higher in the parallel direction compared to the perpendicular direction of the fiber orientation. A curious cyclic fluctuation was found in the ionic conductivity with time. The observed behavior was explained by considering the distance between fibers and transport speed of ions used in this study.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.486-494
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• 2021

A rice (Oryza sativa L.) cultivar of the SPP (stakeholder participatory program) and ordinary rice were characterized based on water-absorption properties and cooked rice texture. During rice soaking, the rice grain transformed from transparent to opaque (white), indicating that water molecules diffused into the rice grain during soaking. In addition, cracks in the internal structure of soaked rice gradually increased with an increase in soaking time. Water absorption increased rapidly up to 20 min, but no increment was observed after 30 min of soaking. At this point, the entire areas of the soaked rice grain turned white, indicating that water absorption had reached saturation. SPP rice showed lower hardness and higher stickiness in its cooked form than ordinary rice, suggesting that SPP rice could be a more preferable choice than ordinary rice. Furthermore, cooked SPP rice was more edible in terms of hardness and stickiness after being kept warm for 12 h than ordinary rice. These results indicated that cooked SPP rice exhibited slow retrogradation and improved taste.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.910-915
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• 1996

Ascidian muscle was blackened during the frozen storage, so the prevention against blackening was investigated. Low storage temperature and packaging in polyethylene bags delayed the blackening of ascidian muscle during the frozen storage. The blackening was prevented by dipping for $3{\sim}5$ minutes in 3% brine solution containing 0.3% citric acid, packaging in the polyethylene bag, freezing at $-45^{\circ}C$ for 5 hours and storing at $-20^{\circ}C$. Under this condition, the color and the quality of frozen ascidian muscle were nearly not changed for 200 days.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.5 no.3
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• pp.38-52
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• 2014

도시주민생활에 없어서는 안 될 주요한 사회간접자본시설인 하수도, 하수도처리시설 등의 콘크리트 구조물에 대한 부식열화는 현재 세계 각국에서 급속히 진행되고 있다. 콘크리트 구조물은 반영구적인 것으로 인식하고 있다. 그러나 각종 열화 인자에 의해 구조물의 사용수명은 급속히 단축된다. 하수시설 내에서는 황산이외에도 다양한 염류에 의하여 콘크리트구조물이 부식될 가능성이 있지만 황산에 의한 부식이 가장 대상범위가 넓고 부식속도가 빠르기 때문에 부식현상이 발견되면 급속하고 적절한 대응조치가 필요하다. 열화예측결과 및 구조물의 공용연수를 감안한 신뢰성이 높은 공법의 도입이 필요하며 이러한 조건에 적합한 유기재료와 무기재료의 복합 특성을 발휘하는 갱생공법에 사용되는 주요 소재의 실험적 특성에 관하여 고찰하였다. 그 결과 경질염화비닐(이하 프로파일)은 내외수압 저항성에서 3분간 $1kgf/cm^2$의 압력에도 누수 및 압력의 이동이 없었으며 약품침지에 따른 중량변화량이 $0.2mg/cm^2$이하로 산에 대한 변화량은 거의 없었다. 주입재인 모르타르의 산성에 대한 저항성은 일반 콘크리트에 비해 우수하였으며 기존 모르타르에 비해 비확선성 또한 우수하였다. 장거리압송시험은 200m까지 안정적인 압송이 가능하여 이 기술에 필요한 요구 성능을 확보한 것으로 나타났다.