• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.29-34
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• 2003

In development of the processed food, it is important not only to make the food delicious but to enhance its storage span and thermal stability without change in color, which greatly affects the tastes. Protopectinase (PPase) from Bacillus subtilis EK11 hydrolyses or dissolves protopectin in the middle lamella of plant tissues with the resultant separation of plant cells from each other, called enzymatic maceration. With the PPase, persimmon was enzymatically macerated to separate cells to primary cell wall without damage. Recovery rates of persimmon treated with PPase and mechanical maceration were 95% and 85%, respectively. Total and reducing sugars, crude protein and fat in the enzymatic maceration were well preserved as in the mechanical maceration. Importantly, over 50% of vitamin C, which is the most unstable component during the mechanical maceration, remained with an intact form for one day after the enzymatic treatment. When the suspensions of persimmon macerated with both treatments were stored at 4$^{\circ}C$ for 9 days, the mechanically macerated persimmon suspension was decolorized, whereas decolorization, was not found in the enzymatically macerated persimmon suspension. Moreover the mechanically macerated persimmon was greatly deteriorated after heat treatment at 10$0^{\circ}C$ for 60 min, whereas cells of the enzymatically separated persimmon suspension appeared to be stable, indicating increased thermal stability Thus, the PPase treatment of persimmon could be a better choice for preparation of highly valuable and functional processed food as well as for increase in preservation period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.3
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• pp.255-264
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• 1989

The results of toxicity test using mice and rats for ethanol extract of Bracken Fern collected in Kwang Ju area were shown as follows ; Up to the dose of 10g per kg of mice administered intraperitoneally there was no lethal toxicity so that it was impossible to calculate the median lethal dose $(LD_{50})$. For the first 7 days experiment all rats administered frond extract grouping in 40mg, 400mg, and 1200mg per kg of rat as the daily oral doses did not show any characterized sign in the weight gain rate, anatomical findings, and biochemical studies. For 3 weeks following the first week the weight gain rates of all test group were reduced to $4.2{\sim}7%$ below the weight gain rate of control. In this period serum GPT, GOT, and Alkaline phosphatase value were increased significantly indicating the symptoms of Bracken Fern poisonings. The pathological findings of all test groups for 28 days showed acute and chronic intestinal lesion and liver damage with steatosis especially in 1200g/kg rat groups. In this experiment the Bracken poisonings appeared slowly in rats of 400mg/kg and 1200mg/kg for two weeks and in rats of 40mg/kg for 3 weeks, showing the symptoms of lowering of weight gain rate, subacute hepatitis, hepatic steatosis and enteritis in 28 days experiment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.791-796
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• 2007

As large-scale buildings, skyscrapers, and multi-purpose buildings recently increase in numbers dramatically, the internal space of such buildings becomes more and more large and complicated accordingly. Since such structures usually accommodate a number of random people, the potential possibilities of disastrous tragedies are high, and the rates of injury and physical damage caused by the complicated system of the building also increase as well. However, most of the shelter designs of the existing buildings are based on the specifications according to the assigned laws and involved regulations. In this case, only general criteria are referred to regardless of the characteristics of each structure while other disaster-related features are not taken into consideration sufficiently. Since any actual fire may cause a terrible calamity, in such plans, shelter inducement can be neither safe nor effective. Thus, this study examines and analyzes currently run disaster prevention systems and shelter inducement facilities with COEX Mall as its subject, and analyzes the responding system to each situation based on the fire scenarios by means of As-Is Model. Through this analysis, presented are the measures to solve the problems of current disaster prevention systems and to improve shelter inducement methods effectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.457-457
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• 2010

Flexible organic light emitting diodes (F-OLEDs) requires excellent moisture permeation barriers to minimize the degradation of the F-OLEDs device. Specifically, F-OLEDs device need a barrier layer that transmits less than $10^{-6}g/m^2/day$ of water and $10^{-5}g/m^2/day$ of oxygen. To increase the life time of F-OLEDs, therefore, it is indispensable to protect the organic materials from water and oxygen. Severe groups have reported on multi-layerd barriers consisting inorganic thin films deposited by plasma enhenced chemical deposition (PECVD) or sputtering. However, it is difficult to control the formation of granular-type morphology and microscopic pinholes in PECVD and sputtering. On the contrary, atomic layer deoposition (ALD) is free of pinhole, highly uniform, conformal films and show good step coverage. Thus, $Al_2O_3/TiO_2$ multi-layer was deposited onto the polyethersulfon (PES) substrate by electron cyclotron resonance atomic layer deposition (ECR-ALD), and the water vapor transmission rates (WVTR) were measured. WVTR of moisture permeation barriers is dependent upon density of films and initial state of polymer surface. A significant reduction of WVTR was achieved by increasing density of films and by applying low plasma induced interlayer on the PES substrate. In order to minimize damage of polymer surface, a 10 nm thick $TiO_2$ was deposited on PES prior to a $Al_2O_3$ ECR-ALD process. High quality barriers were developed from $Al_2O_3$ barriers on the $TiO_2$ interlayer. WVTR of $Al_2O_3$ by introducing $TiO_2$ interlayer was recorded in the range of $10^{-3}g/m^2.day$ at $38^{\circ}C$ and 100% relative humidity using a MOCON instrument. The WVTR was two orders of magnitude smaller than $Al_2O_3$ barriers directly grown on PES substrate without the $TiO_2$ interlayer. Thus, we can consider that the $Al_2O_3/TiO_2$ multi-layer passivation can be one of the most suitable F-OLEDs passivation films.

• Biomolecules & Therapeutics
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• v.2 no.4
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• pp.369-375
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• 1994

A polysaccharide, G009, isolated from Ganoderma lucidum IY 009, was subjected to investigating on general pharmacology. This material at the large oral doses of 1000 and 2000 mg/kg in mice did not exhibit any abnormal behaviors and another effects on central nervous system. It also had no influences on hexobarbital-induced sleeping time, rotarod test and spontaneous activity test at each oral dose of 1000 mg/kg in mice. No effects on the body temperature and on acetic acid induced writhing syndrome in mice were observed with its oral administration at 1000 mg/kg, and the convulsions induced by strychnine and pentetrazole were not inhibited at its oral doses of 1000 mg/kg in mice. The solution of G009 as given intravenously at the doses of 30 and 60 mg/kg in rabbit had no influences on blood pressure and respiration rates and depth. In isolated organs of rat uterus and fundus muscles and guineapig ileum and trachea, it did not show any contraction or relaxation at the concentrations of 2$\times$10$^{-3}$ g/ml, and the contractive actions produced by oxytocin, acetylcholine, serotonin and histamine were not inhibited at the same doses. This material showed no effect on intestinal propulsion test in mice and gastric secretion in rats at the oral doses of 1000 mg/kg. However, it is interesting that the material exhibited potent inhibition of acidified aspirin induced gastric damage at the doses of 500 and 1000 mg/kg in rats.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.4
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• pp.339-345
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• 2008

The heat exchanger tube in nuclear power plants is mainly fabricated from nonferromagnetic material such as a copper, titanium, and inconel alloy, but the moisture separator & reheater tube in the turbine system is fabricated from ferromagnetic material such as a carbon steel or ferrite stainless steel which has a good mechanical properties in harsh environments of high pressure and temperature. Especially, the moisture separator & reheater tubes, which use steam as a heat transfer media, typically employ a tubing with integral fins to furnish higher heat transfer rates. The ferromagnetic tube typically shows superior properties in high pressure and temperature environments than a nonferromagnetic material, but can make a trouble during the normal operation of power plants because the ferrous tube has service-induced damage forms including a steam cutting, erosion, mechanical wear, stress corrosion cracking, etc. Therefore, nondestructive examination is periodically performed to evaluate the tube integrity. Now, the remote field testing(RFT) technique is one of the solution for examination of ferromagnetic tube because the conventional eddy current technique typically can not be applied to ferromagnetic tube such as a ferrite stainless steel due to the high electrical permeability of ferrous tube. In this study, we have designed RFT probes, calibration standards, artificial flaw specimen, and probe pusher-puller necessary for field application, and have successfully carry out RFT examination of the moisture separator & reheater tube of nuclear power plants.

• Food Science and Preservation
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• v.15 no.5
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• pp.630-634
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• 2008

The effect of packaging methods on the quality characteristics of leaf lettuces was studied during storage at low temperature. Using five commercial packaging types: non-perforated PP (polypropylene) film bags, PP film roll, perforated PP film bags, PET (polyethyleneterephthalate) trays, and micro-perforated LDPE film bags, changes in color, respiration rate, and weight loss of leaf lettuces were investigated. Packaging in non-perforated PP film bags minimized color change and weight loss during storage. The leaf lettuces packaged in non-perforated PP film bags, among the five packaging choices, showed good external appearance and offered the greatest sale potential in the domestic market. However, there were no clear differences in the respiration rates of lettuces packed in various ways. The PET tray afforded very good protection of leaf lettuces from physical damage. The results indicate that the marketability of lettuces may be directly affected by the packaging modes employed, and that the optimal packaging may be non-perforated PP film bags; these keep lettuces fresh during low-temperature storage.

• Structural Engineering and Mechanics
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• v.70 no.1
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• pp.67-80
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• 2019

Strengthening with near surface mounted carbon fibre reinforced polymers (NSM-CFRP) is a strengthening technique that have been used for several decades to increase the load carrying capacity of reinforced concrete members. In Iraq, many concrete buildings and bridges were subjected to a wide range of damage as a result of the last war and many other events. Accordingly, there is a progressive increase in the strengthening of concrete structures, bridges in particular, by using CFRP strengthening techniques. Near-surface mounted carbon fibre polymer has been recently proved as a powerful strengthening technique in which the CFRP strips are sufficiently protected against external environmental conditions especially the high-temperature rates in Iraq. However, this technique has not been examined yet under repeated loading conditions such as traffic loads on bridge girders. The main objective of this research was to investigate the effectiveness of NSM-CFRP strips in reinforced concrete beams under repeated loads. Different parameters such as the number of strips, groove size, and two types of bonding materials (epoxy resin and cement-based adhesive) were considered. Fifteen NSM-CFRP strengthened beams were tested under concentrated monotonic and repeated loadings. Three beams were non-strengthened as reference specimens while the remaining were strengthened with NSM-CFRP strips and divided into three groups. Each group comprises two beams tested under monotonic loads and used as control for those tested under repeated loads in the same group. The experimental results are discussed in terms of load-deflection behavior up to failure, ductility factor, cumulative energy absorption, number of cycles to failure, and the mode of failure. The test results proved that strengthening with NSM-CFRP strips increased both the flexural strength and stiffness of the tested beams. An increase in load carrying capacity was obtained in a range of (1.47 to 4.49) times that for the non-strengthened specimens. Also, the increase in total area of CFRPs showed a slight increase in flexural capacity of (1.02) times the value of the control strengthened one tested under repeated loading. Increasing the total area of CFRP strips resulted in a reduction in ductility factor reached to (0.71) while the cumulative energy absorption increased by (1.22) times the values of the strengthened reference specimens tested under repeated loading. Moreover, the replacement of epoxy resin with cement-based adhesive as a bonding material exhibited higher ductility than specimen with epoxy resin tested under monotonic and repeated loading.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.547-555
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• 2018

In addition to North America and Europe, Korea is also responding to the toxic damage caused by the production and distribution of chemicals. Methods for assessing bio-toxicity of harmful substances have been widely introduced, but it is required of quantitative and speedy information for modeling. For 6 heavy metals, as zinc, copper, chrome, cadmium, mercury and lead, bio-toxicity assessment and kinetics model were constructed using Vibrio fischeri which is widely used luminous bacteria. The degree of luminescence activity and the toxicity of heavy metals were relative limunescence unit, RLU measured as by using a photomultiplier embedded device. The toxicity was assessed by the concentration levels giving under 20% lethality and lethal concentration, $EC_{50}$. In the results, the toxicity order were followed from mercury, lead, copper, chrome, zinc and cadmium. $EC_{{50},{\infty}}$ obtained by trends of $EC_{50}$ by time follows had highly linear agreement with main parameters of bio-toxicity modelling. The average error rates of the reproduced lethality obtained from DAM and TDM model on the basis of body residue, were 10.2% for mercury, lead, copper, chrome and 20.0 for the all 6 methals.