• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.6
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• pp.30-35
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• 2013

To conserve wood resources for papermaking, chemical compositions of the hemp (Cannabis sativa L.) bast fiber cultivated in Korea such as holocellulose, ${\alpha}$-cellulose, lignin, alcohol-benzene extractives, hot and cold water extractives, and ash contents were investigated to manufacture the specialty packaging paper effectively. Significantly very low klason lignin content of 3.3% was accomplished by removing of the outer shell of bark. Laboratory soda pulping method which is very useful for the nonwood fiber was adapted, and it was found that there was no significant difference in both kappa number and H-factor between 25% and 30% NaOH charge. Hemp pulp cooked with the laboratory digester in 25% NaOH at $170^{\circ}C$ were mixed together with the wood pulp(NBKP:LBKP=1:1) in order to find the optimum mixture ratio which exhibited acceptable paper strength properties such as tensile index, burst index, and tear strength. When 10% of hemp soda pulps was mixed with 90% of wood pulps comprised of SwBKP and HwBKP (1:1), all physical strength increased significantly. The physical strength decreased as the amount of hemp pulp increased because the cell wall of bast fiber is very thick which causes low conformability and low fiber-fiber bonding. These results showed that paper made of hemp-wood pulp can be used for the specialty packaging paper which requires both the characteristic surface properties and the high physical strength of hemp fiber.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.17-20
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• 2011

Plant biomass is a huge carbon-complex that has potential as a nutrient. Therefore we extracted and separated useful materials for plant growth from tea leaf and stem. The pre-treatment process including high temperature ($200^{\circ}C$) and pressure (20-40 kgf/$cm^2$) was treated for several minutes and extracted at $120^{\circ}C$ for 30-60 minutes. After that the chemical compositions and ingredients were analyzed from that plant-nutrient. As a result of mineral contents, calcium and magnesium concentrations are higher than other minerals. Also the result of carbohydrates analyses has shown that the sugar oligomer consists of xylose(95.3%) and glucose(4.7%), and the sugar monomer consists in the order of xylose (52.7%) > manose (22.8%) > arabinose (10.8%) > galactose (10.2%) > glucose (3.5%). Before applied to field, in vitro plant growth system and formulation were examined. To evaluate the effect of the nutrients, both strawberry green-house and persimmon fields were used in this test. The treated persimmons were heavier than controls scored at 13-22%. In addition, the storage-period was extended in the treated strawberries. Interestingly in the treated strawberry, the contents of polyphenols were increased (38-57%). These results suggest that the plant-nutrient can afford to help for plant growth and storage, and it can be substituted for other commercial nutrients. In conclusion, this plant-nutrient may help to extend eco-friendly or organic farming in Hadong-gun area.

• Food Science of Animal Resources
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• v.33 no.1
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• pp.1-8
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• 2013

The effects of adding goldenrod leaf powder (GLP) and goldenrod stem powder (GSP) (0.1% and 0.5%) to raw ground pork on antioxidant activity were examined. The following six treatment groups were used: Control (without antioxidant), GLP1 (with 0.1% GLP), GLP2 (with 0.5% GLP), GSP1 (with 0.1% GSP), GSP2 (with 0.5% GSP) and AS (with 0.05% ascorbic acid). The chemical compositions, pH values, instrumental color, conjugated diene (CD), free fatty acids (FFA) and thiobarbituric acid-reactive substance (TBARS) value were measured during 15 d of storage at chilled temperatures. The addition of GLP and GSP showed no effect on moisture, protein and fat contents of the samples. However, adding 0.5% GSP increased the ash contents of ground pork (p<0.05). The pH values of treated samples decreased until day 7, and then increased thereafter. The addition of GLP and GSP decreased the $L^*$ and $a^*$ values and increased the $b^*$ value (p<0.05). The CD, FFA and TBARS value of the control were higher (p<0.05) than samples containing GLP and GSP. The addition of GLP and GSP resulted in a significant decrease in CD, FFA and TBARS values. Overall, this study demonstrated that GL and GS could be used as an antioxidant of raw ground pork.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.180-192
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• 2000

One bottle system was recently developed in order to simplify the clinical skills and save chair time after continuous improvements on dentin bonding agents. There has been many studies to measure the bond strength of one bottle systems but no actual work has been done on micromorphologic study of resin-dentin interdiffusion zone after one bottle system application. To evaluate the bonding patterns of various commercially available one bottle systems to dentin, observation of resin-dentin interdiffusion zone under TEM was performed. Caries-free human third molars within one month of extractions were chosen for the experiments. The molars were sectioned 1mm above the cementoenamel junction and got rid of the root portions. Crown portions of the teeth were sectioned parallel to occlusal surface so that dentin discs of 1mm in thickness were remained. 7 one bottle systems and 1 two bottle system were applied according to manufacturer's instructions and followings were the results. 1. In every experimental groups, cross bandings of collagen fiber were distinguishable and tight bon dings between the bonding agents and dentin were observed. 2. Hybrid layer was clearly observed in ONE-STEP$^{(R)}$, Prime & Bond$^{(R)}$ 2.1, Syntac$^{(R)}$ SC, MAC-BOND II groups but it was not clear in Single Bond, D-Liner Dual PLUS, ONE COAT BOND groups. 3. Electron-density of hybrid layer was uniform in pattern in MAC-BOND II, Prime & Bond$^{(R)}$ 2.1 groups but not so uniform in ONE-STEP$^{(R)}$ group. 4. Electron-dense amorphous phase in most superior layer of the resin-dentin interdiffusion zone was characteristically observed in Single Bond, Syntac$^{(R)}$ SC, ONE COAT BOND groups. It can be concluded that bondings between the dentin bonding agents and dentin can be various in pattern according to their chemical compositions and the condition during applications.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.770-776
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• 2001

To compare chemical properties of irradiated legumes (soybean, peanut, red bean, mung bean) produced in Korea and China, radiation-induced hydrocarbons from the samples were investigated. The legumes were gamma-irradiated at 0.5, 1, 2 and 4 kGy, from which lipid was extracted with hexane. Hydrocarbons were separated by florisil column chromatography and then analyzed with GC-MS method. The chromatograms of irradiated samples showed several radiation-induced hydrocarbons, which were affected by the fatty acid compositions of legumes. Hydrocarbons, such as 1, 7, 10-hexadecatriene (16:3),6,9-heptadecadiene (17 : 2), 1, 7-hexadecadiene (16 : 2) and 8-heptadecene (17 : 1), were predominantly detected in soybean, peanut and red bean irradiated at 0.5 kGy or above, whereas 17 : 1 was not found in mung bean. The detected amount of hydrocarbons increased with irradiation doses. There is no apparent difference in qualitative and quantitative profiles of the corresponding hydrocarbons depending on the origin of legumes.

• Korean Journal of Metals and Materials
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• v.50 no.2
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• pp.136-145
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• 2012

Resistance spot welding of TRIP780 steels was investigated to enhance understanding of weld fracture mode after tensile shear testing (TST) and L-shape tensile testing (LTT). The main failure mode for spot welds of TRIP780 steels was partial interfacial fracture (PIF). Although PIF does not satisfy the minimum button diameter (4${\surd}$t) for acceptable welds, it shows enough load carrying capacity of resistance spot welds for advanced high strength steels. In the analysis of displacement controlled L-shape tensile test results, cracks initiated at the notch of the faying surface and propagated through the interface of weldments, and finally, cracks change path into the sheet thickness direction. Use of the ductility ratio and CE analysis suggested that the occurrence of PIF is closely related to high hardness and brittle welds, which are caused by fast cooling rates and high chemical compositions of TRIP steels. Analysis of the hold time and weld time in a welding schedule demonstrated that careful control of the cooling rate and the size of a weld nugget and the HAZ zone can reduce the occurrence of PIF, which leads to sound welds with button fractures (BFs).

• Elastomers and Composites
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• v.40 no.2
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• pp.83-92
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• 2005

To develop an automotive fuel hose suitable to the international environmental regulation, FKM rubber materials as an inner material of fuel hole were prepared with different chemical compositions. Measurement of the properties of thermal resistance, oil resistance, fuel resistance, gas permeability including fundamental properties were performed to investigate compatibility for a fuel hose material. Fundamental properties, thermal resistance, oil resistance, fuel resistance and permeability of FKM rubber materials were improved with fluorine content. When the carbon content was 20 phr, FKM compounds with fluorine contents of 66%, 09% and 71% were shown to satisfy the specification oi fuel hose. The gas permeability of NBR and FKM compounds was measured on the mixed fuel oils prepared with isooctane-toluene and gasoline-methanol. FKM rubber materials showed a small difference in penetrated amount of fuel and showed a permeability superior to NBR material. he permeability of FKM rubber materials was not influenced by the contents of fuel oil. Thermal properties of 69% FKM rubber experienced by permeability testing were not variated.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.314-322
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• 2004

This research has been undertaken to increase availiability of native Camellia japonica leaf and flower in Korea as a edible-medicinal resource. Chemical compositions, antioxidant and antimicrobial activities in different parts of camellia were investigated. Crude protein contained the highest in young leaves(14.22%) but less than 10% in different parts. The contents of crude fat and crude ash were 60.48% in seeds and 5.16% in mature leaves, respectively. Methanol extract of young leaf, flower, and flower bud in camellia showed strong antioxidant activity compared with different parts. Also, antioxidant activity of these was higher than that of BHT, but weaker than that of VtC. Antioxidant activity of various parts in camellia were in order of young leaf ＆gt; flower bud ＆gt; flower ＆gt; mature leaf ＆gt; stem ＆gt; bark. Extracts of mature leaf and bark had a remarkable antibacterial activity(0 CFU/$m\ell$) on Bacillus subtilis. The young leaf extract displayed effective growth inhibition against B. subtilis, Candida albicans, and Trichosporon beigelii.

• Journal of Soil and Groundwater Environment
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• v.17 no.4
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• pp.51-62
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• 2012

Effects of climate change on groundwater system requires understanding the groundwater system in temporal and spatial scales through the long-term monitoring. In this study, the spatio-temporal variations of groundwater were analyzed through the continuous observation of water level, electrical conductivity (EC) and water temperature with automatic data-loggers and sampling in a Gwangneung catchment, Korea, for the four years from 2008 to 2011. Groundwater monitoring were performed at the nest-type wells, MW1 and MW2, located in upsteam and downstream of the catchment, respectively. During the survey period, both the total amount of annual precipitation and the frequency of concentrated rainfall have increased resulting in the elevation of runoff. Water level of MW1 showed no significant fluctuations even during the rainy season, indicating the confined groundwater system. In contrast, that of MW2 showed clear seasonal changes, indicating the unconfined system. The lag-time of temperature at both wells ranged from one to three months depending on the screened depths. Results of chemical analyses indicated that major water compositions were maintained constantly, except for the EC decreases due to the dilution effect. Values of the stable-isotope ratios for oxygen and deuterium were higher at MW2 than MW1, implying the confined system at the upstream area could be locally developed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.3
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• pp.155-161
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• 2021

This study was conducted to estimate the effect of different cutting lengths on fermentation characteristics and aerobic stability of whole crop rice (WCR) silage. The WCR was harvested at the yellow ripe stage (43.7%, DM), and then cut at 5 (R05), 10 (R10), and 20 cm (R20) of the theoretical length of cut with no cut WCR (R60). Each forage was ensiled into 20 L mini bucket silo (5 kg) for 150 days in quadruplicates. The cutting lengths were not affected the chemical compositions of WCR silage (p > 0.05). The pH (p < 0.001) and concentration of ammonia-N (p = 0.022) in WCR silage were increased linearly with the increase of cutting length. The concentration of lactate had quadratic effect (p = 0.007), which was highest in R20 silage (p < 0.05). The concentration of acetate was increased linearly (p = 0.014), but the concentration of butyrate was decreased linearly (p = 0.033). The lactic acid bacteria count was decreased linearly (p = 0.017), and yeast count had quadratic effect (p = 0.009), which was the highest in R20 silage (p < 0.05). Aerobic stability had strong quadratic effect (p < 0.001), which was the highest in R20 silage (p < 0.05). In conclusion, R60 silage had highest pH by a linear increase of ammonia-N concentration and led to low aerobic stability. While R20 silage had the lowest pH by high lactate concentration and led to high aerobic stability.