• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.189-196
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• 2007

The purpose of this study was to analyze steel corrosion resistance of concrete containing copper slag. The specimens were made with normal portland cement and pozzolan materials with various replacement ratio and with W/B ratio ranging from 35% to 55%. Compressive strength, coefficient of chloride diffusion, corrosion area ratio and weight reduction ratio were determinated for the test. The results show that the concrete with pozzolan materials is superior resistant to chloride ions compared to the concrete without pozzolan materials. It was observed that blast furnace slag replacement ratio of 20% gives the best results with respect to chloride ion penetration and corrosion tests and observed that copper slag replacement ratio of 10% gives the seperior resistance compared to normal concrete.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.739-744
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• 2013

In this study, torrefaction was performed to improve fuel properties of Larch. The optimal condition for torrefaction was investigated by response surface methodology. The torrefaction temperature and time ranged $220{\sim}280^{\circ}C$ and 20~80 min, respectively. As the torrefaction temperature and time increased, the carbon content of torrefied biomass increased from 49.36 to 56.65%, while its hydrogen and oxygen contents decreased from 5.56 to 5.48% and from 37.62 to 31.67%, respectively. The weight loss and calorific value increased with SF, while energy yield decreased. At the severe torrefaction condition (SF 7), the weight loss and calorific value were 26.58% and 22.30 MJ/kg, respectively. The energy contained in torrefied biomass increased to 20.41%, when compared with the untreated biomass. As the torrefaction severity increased, the energy yield decreased due to the relatively high weight loss of biomass. Therefore, the highest energy yield was obtained at high calorific value and low weight loss of biomass (SF 5.72).

• Applied Biological Chemistry
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• v.42 no.3
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• pp.223-228
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• 1999

The storage effects of satsuma mandarin(Citrus unshiu Marc. var. miyagawa) by humidity control during storage; 90% relative humidity (RH) and 85% RH at $3^{circ}C$, and room temperature were investigated. After 98 days' storage, weight losses were 3.40% for 90% RH, 6.92% for 85% RH, and 11.87% for room temperature storage. Decay ratio was increased rapidly from 3.87% on 98 days' to 48.75% on 126 days' storage for 90% RH. Soluble solids and flesh ratio were declined gradually, but the differences were not significantly. Firmness of fruits was continuously reduced during storage, especially on room temperature storage by the softening of the fruits. Acid content and vitamin C were gradually reduced during storage. Coloration was continuously progressed on room temperature, compared to cold storage. In order to keep freshness of the fruits, optimum storage period of early variety of Satuma mandarin was regarded for 100 days at $3^{circ}C$, 85% RH on the basis of sensory evaluation and chemical compositions.

• Journal of the Society of Disaster Information
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• v.14 no.3
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• pp.343-351
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• 2018

Purpose: Recently, As the size of the structure increased, the necessity of reducing its weight was raised. To reduce weight In concrete structures, a hollow slab is proposed as an alternative for weight reduction effect. Method: It is difficult to construct the hollow body due to buoyancy, and the shear performance is insufficient due to the decreased cross section. Slabs were fabricated using unidirectional hollow bodies such as PVC pipes, and experiments were conducted about construction performance and structural performance. Results: The buoyancy preventive device has been improved the construction performance by preventing floating hollow body, it has been confirmed that it has adequate performance to be used as a hollow slab system because it has enough expected shear performance. Coclusion: Hollow ratio has a little connection with bending performance, but after the yielding load, it is necessary to consider the secondary stiffness of structure, and is is supposed that the decrease of shear performance with the increase of hollow core ratio can be complemented with shear reinforcement.

• Elastomers and Composites
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• v.49 no.2
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• pp.144-148
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• 2014

Compression set (CS) and weight loss by thermal degradation of the ACM rubber composite sample prepared for an automotive part were measured simultaneously at several given temperatures of $150^{\circ}C$, $160^{\circ}C$, $170^{\circ}C$, and $180^{\circ}C$. Using the relationship between them, thermal life of the sample could be predicted at a given operating temperature by applying Toops method which is based on the analysis of non-isothermal TGA thermograms. Conversion by weight loss showed a linear relationship with CS changes, exhibiting 4.2% at CS 40%. Activation energy of thermal degradation was calculated as 120.2 kJ/mol at 4.2% of weight loss from Flynn-Wall-Ozawa analysis. When the expected life was set as time to reach CS 40% at $120^{\circ}C$, the life time of the sample was calculated as 9,700 hrs when Toops method was applied.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.360-368
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• 2017

In order to investigate the durability of high performance polymer concrete composites, polymer concrete specimens were prepared using the ortho-type unsaturated polyester resin (UPR) and iso-type UPR as a polymer binder and the calcium carbonate and silica fine powder as a filler. The durability of polymer concrete specimens was measured by hot water resistance, chemical resistance, pore analysis and SEM observation. The compressive strength of the specimen using the iso-type UPR was higher than that of using the ortho-type UPR, and the compressive strength of the specimen using the silica fine powder was higher than that of using the calcium carbonate filler. From hot water resistance results, it was found that the specimen using the iso-type UPR was superior to that of using the ortho-type UPR and the specimen using the calcium carbonate filler was superior to that of using the silica fine powder. The compressive strength reduction rate was measured after the chemical resistance test and the sodium hydroxide solution showed the highest reduction rate, followed by sulfuric acid, hydrochloric acid and calcium chloride solutions. When using the alkaline solution of sodium hydroxide, the weight reduction rate of the specimen using calcium carbonate was lower than that of using silica fine powder, while for the acidic solutions of sulfuric acid and hydrochloric acid, the weight reduction rate of the specimen using the silica fine powder was lower than that of using calcium carbonate.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.424-430
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• 2012

In this study, laccase activity, rate of weight loss and degree of lignin degradation of pine wood chips were determined during the liquid and solid state incubation with Polyporus brumalis. The results showed that laccase enzyme activity at untreated wood chip was gradually decreased after 20 days, but enzyme activity with wood chip treatment showed 10 times higher than untreated ones at 60 incubation days. Rate of weight losses of pine chip and rate of lignin loss were 23.4% and 6.3% by P. brumalis during 80 incubation days. Gene expression of pblac1 from P. brumalis was 3 times increased under pine chip treatment at 40 incubation days. Consequently, laccase activity of white rot fungi, P. brumalis, was increased at incubation with wood chip and pblac1 gene was important factor of lignin degradation. Therefore, to regulate lignin degrading enzyme gene expression by using the tools of biotechnology will be able to develop superior strains and it will be useful for pretreatment of lignocellulosic biomass at bioethanol production.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.833-841
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• 2010

This study was conducted to develop patties by substituting a portion of meat by bamboo (Sasa borealis) leaf extract (SBE) and/or cooked rice. Four types of patty were prepared: Control, S, SI, and SII. S was the patty for which 2.5% of meat was substituted with SBE. SI and SII were the patties with 25% or 50%, of meat, respectively, substituted with cooked rice containing SBE. The moisture contents of S, SI, and SII patties were not changed. The compositions of fat, cholesterol, and protein of S, SI, and SII patties were decreased. Cooking loss of weight as well as the diameters of S, SI, and SII patties were decreased. pH was increased in S patty, hardness was reduced in SI and SII patties, and malondialdehyde values were lowered in S, SI, and SII patties, compared to control. The S, SI, and SII patties were evaluated higher for color in sensory tests and preference tests. Through preference tests of burgers with these patties, the overall taste of the SI patty was assessed highly among the 4 patties. Therefore, it may be concluded that developing a patty by substituting a portion of meat with SBE and/or cooked rice may be worthwhile.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.1-7
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• 2002

Characteristics (salt concentration, weight loss, soluble solid content, moisture content, and textural properties) of radish cube $(2{\times}2{\times}2\;cm)$ were evaluated during salting. Three different summer radish cultivars harvested in high land were immersed into 15% brine solution (radish : brine solution = 1 : 2) at $15^{\circ}C$ for 4 h. The time required to reach the optimum salt concentration (3%) was different among cultivars; 3 h for 'Bakbong', 4 h for 'Kwandong' and '92343'. Similar weight loss (about 24-26%) of salted radish cubes was found among cultivars. While the highest value of weight loss of salted radish cubes was observed with '92343', the lowest, 'Bakbong'. Hardness decreased during salting; the highest value of hardness was observer with 'Kwandong', the lowest, 'Bankbong'. The sample of '92343' has the lowest moisture content but has the highest soluble solid content and hardness, while 'Bakbong' has the highest moisture content, but has the lowest soluble solid content and '92343'. In separate experiments, seasonal variations in characteristics of salted radish cubes at optimum salt concentration (3%) were observed: for 'Bakbong', salt concentration, weight loss, soluble solid content, and hardness, and for 'Bakwang', salt concentration, weight loss, and hardness were higher in autumn cultivars than in spring or summer one, while moisture contents of both cultivars were higher in spring or summer cultivars than in autumn one.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.58-63
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• 1997

The experiment was done to clarify the effect of keeping material and storage temperature on weight and quality of Chinese yam (Dioscorea opposita) tuber. After the yam tubers were placed into the plastic boxes filled with different keeping materials [polyethylene (PE) film, hull, soil, sand, vermiculite], they were stored under different storage temperature(room, cold) from Oct. 15 to Mar. 15 when all the characters related to the tubers were measured. Soil or PE film as keeping materials was the lowest sound tuber rate when stored at room or cold temperature, respectively, while vermiculite was the highest in both storage temperature. When PE film and vermiculite in both storage temperatures were used as keeping materials, tuber weight were less reduced than the others. Brightness of chromaticity and moisture content were lower in room temperature storage than in cold temperature storage although the characteristics related to marketability were not affected by storage temperature. PE film had greater brightness and value 'a' of chromaticity but lower its 'b' value in the latter temperature than in the former temperature. Vermiculite, however, did the reverse result in comparison with PE film.