• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.1
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• pp.37-46
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• 1999

Water vapor permeability of films is commonly calculated from the water vapor transmission rate of the film measured using a permeability cup method which is essentially a gravimetric method. This method was originally developed for petroleum based plastic films with low water vapor permeability. In the case of hydrophilic bio-polymer films, the resistance caused by a stagnant air layer, which is developed between the underside of the film mounted on the cup and the surface of the desiccant saturated salt solution or distilled water, can be significant and, if neglected, ran lead to underestimation of water vapor transmission rates. Therefore, it is necessary to correct water vapor transmission rate data to accurately estimate the water vapor permeability of bio-polymer films.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.11a
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• pp.50-53
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• 1996

This paper reports the experimental results for the determination of the overall partition coefficient of VOCs in unsaturated soil, A chromatographic method was used for the determination of gaseous partition coefficients to natural soil under various water content conditions. The equilibrium vapor pressure of water over saturated salt solution was used to fix the relative humidity of the air and control the water content of the soil systems. The transport behavior was studied for dichloromethane, trichloroethane and dichlorobenzene pollutants, with log octanol-water partition coefficients(log $K_{ow}$ ) which range from 1.25 to 3.39, or water to soil partitioning which varies by 135 times; water solubility constants which vary by 3 times; and vapor pressures which range from 1 to 362 torr. Water content of the soil had a pronounced effect on the effective partition coefficient(between gas and soil + water stationary phase) as well as on the effective dispersion coefficient.

• Journal of the Korea Furniture Society
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• v.19 no.4
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• pp.229-234
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• 2008

In a previous study, it was revealed that three major softwoods, Japanese pine, Korean pine and Japanese larch, heat-treated at $220^{\circ}C$, could produce high quality dark-colored boards. It is known that heat treatment decreases the hygroscopicity of wood. The hygroscopicity of major domestic softwoods and hardwoods heat-treated at $220^{\circ}C$ was investigated by a saturated salt solution method and compared with that of black and white charcoals. Equilibrium moisture contents of wood decreased with the increase of heat treatment time. Isotherm shapes of wood species were different from those of charcoals. Heat treatment decreases the equilibrium moisture contents of black locust more than those of Korean pine and Japanese larch. It was found that surface hardness of wood is improved by heat treatment to a certain extent, but a longer heat treatment causes thermal degradation, resulting in the decrease of the surface hardness.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.142-153
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• 1995

This study is undertaken to investigate proper condition and dissolution method of silk fibroin to use it functional material as powder or membrane. Silk fibroin was dissolved with calcium chloride ethanol aqueous solution and hydrochloric acid. When silk fibron was dissolved with calcium chloride ehanol aqueous solution, main chain of silk fibroin was degradaded and molecular conformation was changed. Silk fibroin powder was made from silk fibroin solution. It showed lower thermal decomposition temperature and crystallinity than those of native silk fibroin. And Its molecular conformation was random coil structure. By acid gydrolysis, main chain of silk fibroin was attacked randomly. Silk fibroin powder from hydrolysate showed high crystallinity and thermal decomposition temprature. $\beta$-form molecular conformation was found by IR and X-ray diffraction. Silk fibroin powder form dissolved part with hydrochloric acid showed low thormal decomposition temperature but high crystallinity. During acid hydrolysis, transition of molecular structure of silk fibroin occurred, and it changed to $\alpha$-helix. Silk fibroin film was achieved by casting silk fibroin solution by ehanol solution or saturated vapor treatment, and its molecular conformation changed to $\beta$structure.

• Korean Journal of Veterinary Research
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• v.26 no.2
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• pp.329-336
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• 1986

This survey was conducted to investigate the prevalence of the internal parasites of Holstein cattle rearing in western Gyeongnam including Chinyang, Sachun, Namhae, Hadong, Sanchung, Hamyang, Geochang and Hapchun Area(Gun). A total of eight hundred and twenty five heads of Holstein cattle was randomly selected for the faecal examinations and the internal parasitisms were examined by floatation method using saturated salt solution and sedimentation method using 0.5% trio-soap solution. The relults obtained are summarized as follows: 1. The overall rate of internal parasite infections was 67.2% with infection of 554 cases and the non-infected rate was 32.8% with 271 cases from the total number of 825 samples. 2. A total fourteen species of parasites was identified from 825 faecal samples of Holstein cattle and the infection rate of each species of parasites was 3.0% in Haemonchus contortus, 2.7% in Cooperia spp., 1.8% in Bunostomum phlebotomum, 1.6% in Oesophagostomum radiatum, 1.2% in Ostertagia ostertagi, 1.0% in Trichuris bovis, 0.8% in Strongyloides papillsus, 0.4% in Nematodirus spp., 0.1% in Trichostrongylus spp., 57.3% in Paramohistomum spp., 31.2% in Fasciola hepatica, 0.6% in Eurytrema pancreaticum, 0.7% in Moniezia expansa and 5.1% in Eimeria spp. 3. The combined infection of internal parasites was 38.1% in single species, 27.0% in double and 2.1% in triple infections. 4. The EPG levels of each species of parasites were very low in all infected cases except trematodes showing no clinical symptoms.

• Journal of the Korean Wood Science and Technology
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• v.42 no.1
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• pp.13-19
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• 2014

Three heat-treatment schedules were applied to $90{\times}90mm$ dimension square lumber of Pinus koraiensis, one of major domestic species, and their colors and physical properties were investigated for obtaining an optimum schedule. Each square lumber was heat-treated three times. The temperatures of $170^{\circ}C$ and $190^{\circ}C$, and the time of 9 hours and 13 hours were used for the first heat-treatment. The schedule of $190^{\circ}C$ and 7 hours were used for the next two heat-treatments. The averages of brightness $L^*$ decreased linearly as the heat-treatment repeated and its standard deviations also decreased slightly. While the averages of color difference ${\Delta}E^*$ increased linearly as the heat-treatment repeated and its standard deviations also increased slightly. The average compressive strength of the heat-treated specimen was higher than that of the control by 9%, which deviates from previous reports. ASE and WPG of the heat-treated specimens were measured to confirm that heat-treatment improved dimensional stability significantly.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.476-483
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• 1993

The moisture sorption characteristics of commercially produced seasoned dried layer (Porphyra yezoensis) was investigated by measuring sorption isotherms. The laver and two kinds of desiccant (silica gel and zeolite based desiccant) were used at temperatures of 30, 40 and 5$0^{\circ}C$ respectively using the method of saturated salt solution. Time to reach the equilibrium moisture content at each temperature and relative humidity varied from 4~6hr for the laver to 20~25hr for the silica gel and 43~46hr for the zeolite. The isotherms of the layer and the desiccants showed the characteristic sigmoidal curve. Monomolecular layer moisture content calculated using the BET equation at each temperature (30, 40, 5$0^{\circ}C$) were 5.26, 4.46 and 3.49% (d.b.) for the laver, 17.32, 15.24 and 12.89% (d.b.) for the silica gel, 16.89, 14.92 and 14.44% (d.b.) for the zeolite, respectively, Both desiccants showed higher values of the monomolecular layer moisture content than the laver. In all cases, the monomolerular layer moisture contents were decreased linearly as the temperature was increased in the experimental ranges. Water vapor transmission rate of the packaged material was also influenced by the temperature, which could be explained by the Arrhenius equation.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.173-180
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• 2013

This study was carried to provide basic data for the research of the effect of PEG impregnation on preventing wood from cracking during heat treatment. Three popular softwood species were selected for investigating the PEG penetration rate and retention depending on PEG molecular weight, PEG retention after heat treatment and their EMCs. The average retentions of PEG400 were reversely proportional to the basic densities of three species and those of the other PEGs showed similar behaviour as well. It is obvious that PEG retention decreased as PEG molecular weight increased with a species. PEG impregnation increased or decreased the moisture contents of the specimens within 2%, and increased their basic densities by 16.8% as a maximum. The Weight Percentage Losses of PEG400 during heat treatment were the largest among three PEG levels, which implied that lower molecular weight PEG leached more than the highers. There was less difference in EMC between PEG impregnated and control specimens at low RH, but their difference increased at high RH.