• Journal of the Korean Wood Science and Technology
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• v.50 no.2
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• pp.93-103
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• 2022

Currently, biofibers are used as a reinforcement in polymer composites for structural elements and construction materials instead of the synthetic fibers which cause environmental problems and are expensive. One of the chemicals with a pH close to neutral that can be potentially used as a modified fiber material is sodium chloride (NaCl). Therefore, this study aims to investigate the characteristics of a composite board made from NaCl-treated kenaf fiber. A completely randomized design method was used with consideration of two factors: the content of NaCl in the treatment solution (1 wt%, 3 wt%, and 5 wt%) and the duration of immersion of fibers in the solution (1 h, 2 h, and 3 h). The NaCl treatment was conducted by soaking the fibers in the solution for different durations. The fibers were then rinsed with water until the pH of the water reached 7 and subsequently dried inside an oven at 80℃ for 6 h. Kenaf fiber and epoxy were mixed manually with the total loading of 20 wt% based on the dry weight of the fiber. Physical and mechanical properties of the fibers were then evaluated based on JIS A 5908 particleboard standards. The results showed that increasing NaCl content in the fiber treatment solution can increase the physical and mechanical properties of the composite board. The properties of fibers treated with 5 wt% NaCl for 3 h were superior with a modulus of elasticity of 2.085 GPa, modulus of rupture of 19.77 MPa, internal bonding of 1.8 MPa, thickness swelling of 3%, and water absorption of 10.9%. The contact angle of untreated kenaf fibers was 104°, which increased to 80° and 73° on treatment with 1 wt% and 5 wt% NaCl for 3 h, respectively.

• Advances in materials Research
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• v.13 no.3
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• pp.161-171
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• 2024

This study aimed to investigate the effect of physicochemical properties and mix ratios of iron ore (oxide feed): coke (reductant) on the carbothermic reductions of iron ore. Coke size was fixed at ≤63 ㎛ while iron ore size varied between 150-63 ㎛ and ≤63 ㎛ respectively. Mix ratios were changed from 100:0 (reference) to 80:20 and 60:40 while the temperature, heating rate and soaking duration in muffle furnace were fixed at 1100 ℃, 10 ℃/min and 1 hour. Particle size analyzer, XRF, CHNS and XRD analyses were used for determination of raw feed characteristics. The occurrence of phase transformations from various forms of iron oxides to iron during the carbothermal reductions were identified through XRD profiles and supported with weight loss (%). XRF analysis proved that iron ore is of high grade with 93.4% of Fe₂O₃ content. Other oxides present in minor amounts are 2% Al₂O₃ and 1.8% SiO₂ with negligible amounts of other compounds such as MnO, K₂O and CuO. Composite pellet with finer size iron particles (≤63 ㎛) and higher carbon content of 60:40 exhibited 45.13% weight lost compared to 32.30% and 3.88% respectively for 80:20 and 100:0 ratios. It is evident that reduction reactions can only occur with the presence of coke, the carbon supply. The small weight loss of 3.88% at 100:0 ratio occurs due to the removal of moisture and volatiles and oxidations of iron ore. Higher carbon supply at 60:40 leads into better heat and mass transfer and diffusivity during carbothermic reductions. Overall, finer particle size and higher carbon supply improves reactivity and gas-solid interactions resulting in increased reductions and phase transformations.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.32-39
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• 2007

This study was carried out to find the optimum treatment condition for the improving germination using the plant growth regulators with $GA_3$ and BAP, to Kentucky bluegrass and Tall fescue showing low germination. $GA_3$ treatment was more effective on the germination of Kentucky bluegrass than BAP single treatment or the combination treatment of $GA_3$ and BAP, regardless of their treatment concentration. Seed germinability was 6 days treatment was significantly better than that of 3 days treatment in the experiment for treatment period of the plant growth regulators. When seeds were treated with $1000{\mu}M$ of $GA_3$ for 6 days, on the percent germination was improved as much as between 10% and 38% comparing with the control. In Tall fescue seed, the percent germination was not significantly improved, although it was slightly increased when the plant growth regulators were treated. For the optimum condition, on percent germination was improved as much as 10% comparing with the control of Tall fescue treated with $1000{\mu}M$ of $GA_3$ for 3 days. Percent emergence fur the seeds of Kentucky bluegrass and Tall fescue treated $GA_3$ in the field was improved as much as $8{\sim}9%$ comparing with the control, and mean emergence time $(E_{50})$ was also faster for $1{\sim}2$ days than that of the control. However, dry weight, plant height and root length showed no significant effects, although those were slightly improved more than those of the control.

• Journal of Aquaculture
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• v.14 no.4
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• pp.221-226
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• 2001

The ethanol extract of root bark of Morus alba strongly inhibited the Gram positive bacteria like Streptococcus sp., Lactococcus garvieae and Staphylococcus sp., but weakly the Gram negative bacteria like Listonella anguillarm and Edwardsiella tarda. It was more effective in liquid medium than in solid medium. The minimum inhibition concentration (MIC) of the extract in liquid medium was 19.8 and 790~1185 $\mu\textrm{g}$/$m\ell$ for the Gram positive and Gram negative bacteria, respectively. The extract concentration, at which the growth was totally inhibited, was 67.2~403.0 $\mu\textrm{g}$/$m\ell$ for the Gram positive bacteria but it was as high as 1185 $\mu\textrm{g}$/$m\ell$ for L. anguillarum and almost ineffective against E. tarda. For diet supplementation of the extract, effective soaking duration was 3 minutes. The fish diet soaked in the extract inhibited the growth of all the tested Gram positive strains, but not the Gram negative strains. The relationship between the weight of fish diet and absorption of the extract by the fish diet was Y=7.5757X + 4.6962($R^2$ = 0.9998).

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.299-307
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• 1988

Several experiments were conducted to investigate the effects of external factors on germination and emergence of Eclipta prostrata (L.)L. The weight of viable achenes doubled as a result of 90 minutes soaking in water. The germination of E. prostrata was significantly improved by alternating temperatures. At a constant temperature of $35^{\circ}C$, only 78% of the achenes germination, whereas at alternating temperatures of 35/$20^{\circ}C$, 96.5% of the achenes germinated. E. prostrata was more sensitive than rice to moisture stress. No germination of E. prostrata achenes occurred in the absence of oxygen. No germination of E. prostrata achenes occurred in the dark or when they were exposed to green, blue, and far-red light. Germination of E. prostrata achenes was influenced by the duration of illumination after absorption of water. Ten hours of illumination was needed for maximum germination and 2 hours for 50% germination. No significant changes in germination of E. prostrata achenes were observed between pH 3 and 10. A high tolerance of E. prostrata achenes to salt was observed. Emergence of E. prostrata achenes was greatly affected by planting depth. In the upland soil, 74.0% of the achenes planted on the soil surface germinated, and no emergence was at planting depths of 0.5 cm or greater.

• Journal of Conservation Science
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• v.37 no.6
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• pp.821-830
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• 2021

The weapons excavated from the de-militarized zones (DMZ) of Korea are vulnerable to corrosion due to the immediate and drastic environmental change. Especially, the chloride ions (Cl^-) in iron weapons cause active corrosion and require removal. In this study, conservation treatment and de-salination was performed for the discovered weapons from excavation sites of soldiers killed in action during the Korean War. Furthermore, an attempt was made to prepare the most stable plan for conservation treatment through the comparative study of soaking weapons in distilled water without chemicals and in a solution of sodium (SSC) at different temperatures. In the preliminarily experiments, the comparison of the eluted Cl^- ions according to different conditions of de-salination showed that the highest number of ions were detected from the de-salination with SSC at a temperature of 100℃, and its duration was much smaller, i.e., 1~2 weeks. Accordingly, for the parts from the guns and rifles amongst other objects, a six-time de-salination was conducted in the SSC solution for 8 hours at 100℃ and subsequently, for 16 hours at room temperature during which the distilled water and SSC were exchanged every week. However, in the case of a loaded rifle, the de-salination was not conducted, considering the risk that the high temperature and pressure by impregnation in vacuum could cause an explosion

• Journal of Sericultural and Entomological Science
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• v.23 no.1
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• pp.47-55
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• 1981

Silk textile finishing has been studied for many years by many workers in order to meet more utilities for various endusers. Such studies, however, could not be successful because any natural fibers are hardly change their natures by artificial treating methods. Textile finishing is of course to improve the mechandise qualities and the poor natures of silk so that it may be available as the best textile fiber in the world. Sometimes, famous trade marked textile plays more power than its quality in the silk market, nevertheless, this should be over line of research activities. Meantime, the silk demand has been also transferred from ladies stocking to other clothes since nylon or other synthetic fibers were developed. That is why, the extension of silk demand should be developed by various research works. Specially, silk is known as difficult textile to handle it during washing or ironing process which happened to depress down the silk usage for house wives. In order to solve such problems, the reporter has been worked for many years and now, he believes that he has developed a proper finishing method to coversuch problems. The developed finishing method may be said to eligible with economical aspect and shorten the dry duration after water washing in half against normal silk textile without harming the specific silk nature. As all of us know, silk fiber starts to denature since it was spinned by silkworm and the fiber is formed as overlapped "S" type curves during its concooning process. After it is made as raw silk or sericin silk, it shows as straight line form, but it changes in to waved form in case refining or degumming process in order return to its original spinned form. Such nature is continued during its textile form and ends with hard ironing nature than other textile fibers. Mean while, the silk fiber keeps to continue its denaturing and this is iniciated by repeat of washing and drying which takes many years to reach its final stage, The reporter has found the iniciating denature of silk by his finishing process, with out heat, decreasing the swollen nature which ended with shortening the drying duration after wash. Each washing was carried out by soaking the previously weighed sample in cold water for one hour, then pressed the sample for ten minutes to eliminate its free water component before weighing with same condition. According to this, the treated silk showed much denaturing after the finishing, but the standard silk progressed the denaturing by and by with the repeat of washing and drying, finally reached the same swollen degree of treated silk, Such treating result explains that the treated silk happened to be stebilized nature by the treating immediately. On the other that the treated silk happened to be stebilized nature by the treating immediately. On the other hand, standard silk may reach to such condition by the time of worn out clothes after repeat of washing and drying for many years while the clothes will be no more useful. The decreased swelling nature has brought about the drying period in half against standard silk after all. Not only the tests of tenacity and elongation but also crease resistance recovery, stiffness and shrinkage tests were carried out after each washing and drying which he has found better result on the treated silk textile against the standard silk. The most important thing was to keep the textile feeling of silk by such finishing work before improve any poor nature of silk. The general silk has a nature to absorb smoke or dirt from its surrounding air and reaches to dirty color shade upon such exposure, but the treated one has improved such nature because of its artificial denaturing, another word, it keeps clean longer than the normal silk. Many previous finishing works could improve some specific nature of silk, but it happened to deprave other important natures. The reporters work is, however, specialized to improve the silk to be useful as Wash and Wear Silk without harming its standard natures. So far, this work happened to be a overall innovative finishing method of silk textile.

• Journal of Mushroom
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• v.2 no.1
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• pp.4-9
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• 2004

This study was carried out to investigate effect of NaCl treatment on growth oyster mushroom and Trichoderma spp. on PDA and in rice straws. We also investigated the possibility of oyster mushroom cultivation using rice straw harvested from the reclaimed land having been drained sea water. Mycelial growth of oyster mushroom was increased by treatment of 0.2% NaCl but decreased by treatment of the higher concentration of NaCl. In the case of the mycelial growth on PDA of Trichoderma spp., no change was found in 0.5%~1.0% NaCl, but decreased in the range of 1.0%~3.0% NaCl and drastically decreased at 5.0% NaCl. In the rice straws treated with different concentration of NaCl solution, mycelial growth of oyster mushroom showed almost same result compare to PDA. The spore formation of Trichoderma mould was almost same in both 0% and 0.3% NaCl, decreased in 0.5% and was not found spores in the higher concentration of NaCl. As increasing salt concentration in the rice straws, the NaO contents were increased. The $K_2O$ contents were decreased before and after sterilization. The moisture content of rice straws showed no difference by treatment of 3.0% NaCl but decreased the moisture by treatment of 5.0% NaCl. No pH change was found in the rice straws treated with NaCl. Mushroom yield in the rice straw of reclaimed land was a little higher than that of normal paddy land straw. The duration of primordium formation was not affected by NaCl concentration in rice straws. The yield of fruiting body in 0.3% NaCl treatment was 2,700kg, which was almost same to non-treated plot, but decreased in 0.5% NaCl. EC value of soaking water after submerging rice straw was higher than before, but NaO content was not changed at both condition.