• Animal Bioscience
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• v.34 no.12
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• pp.1940-1950
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• 2021

Objective: The objective of this study was to explore the effects of maize straw treated with calcium oxide (CaO) and various moisture, on the composition and molecular structure of the fiber, and gas production by fermentation in an in vitro rumen environment. Methods: The experiment used 4×3 Factorial treatment. Maize straws were treated with 4 concentrations of CaO (0%, 3%, 5%, and 7% of dry straw weight) and 3 moisture contents (40%, 50%, and 60%). Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray fluorescence spectroscopy were employed to measure the surface texture, secondary molecular structure of carbohydrate, and calcium (Ca) content of the maize straw, respectively. The correlation of secondary molecular structures and fiber components of maize straw were analyzed by CORR procedure of SAS 9.2. In vitro rumen fermentation was performed for 6, 12, 24, 48, and 72 h to measure gas production. Results: Overall, the moisture factor had no obvious effect on the experimental results. Neutral detergent fiber (NDF), acid detergent fiber, acid detergent lignin, hemicellulose and cellulose contents decreased (p<0.05) with increasing concentrations of CaO treatment. Surface and secondary molecular structure of maize straw were affected by various CaO and moisture treatments. NDF had positive correlation (p<0.01) with Cell-H (H, height), Cell-A (A, area), CHO-2-H. Hemicellulose had positive correlation (p<0.01) with Lignin-H, Lignin-A, Cell-H, Cell-A. Ca content of maize straw increased as the concentration of CaO was increased (p<0.01). Gas production was highest in the group treated with 7% CaO. Conclusion: CaO can adhere to the surface of the maize straw, and then improve the digestibility of the maize straw in ruminants by modifying the structure of lignocellulose and facilitating the maize straw for microbial degradation.

• Textile Coloration and Finishing
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• v.6 no.3
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• pp.27-36
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• 1994

In order to produce a water repellent surface on polyester fabric, samples were treated in the atmosphere of $CF_4$ glow discharge plasma. The samples used in the study were ployester fabric and poyester film. The purpose of film treatment is for the comparison of hydrophobicity with fabric sample at same treatment condition. Radio frequency(13.56MHz) generator was used as electric source and its in put power is 100 Watt. Water repellency was evaluated by contact angle measurement. Result obtained are as follows. 1) Fiber interstice of original fabric was ana lysed as 0.43$\mu$m, and this value was sufficiently ideal for making water repellent fabric. 2) The most favorable setting position of substrate was the center area between two electrodes. 3) Fabric contact angle was higher than film contact angle at same treatment condition, and its difference was more than 50${\circ}$. And it was incapalbe of fabric contact angle measurement when the film contact angle was less than 90${\circ}$. because the fabric is susceptible to absorption of water by the capillary effect. 4) Fabric contact angle can not revealed the precise defferences of surface hydrophobicity, however, the film contact angle showed the real hydrophobic nature. 5) It was not sufficient method to evaluate the hydrophobicity of fabric surface by merely measure of the water contact angle. 6) It showed high water repellent nature at 0.06 torr of $CF_4$ plasma gas pressure and duration of 45 seconds treatment, and it can not be anticipated more improved nature if the pressure and duration of treatment time were increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.67-74
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• 2016

The demand of environmental friendly packaging materials such as pulp mold has been increased. The application of the oil palm biomass, EFB (Empty Fruit Bunch) fiber as natural raw materials to the pulp mold could increase the usability of the pulp mold by the reduced production cost brought from the relatively low cost of EFB. The effects of the EFB(Empty Fruit Bunch) fibers on the properties of pulp mold and on the process efficiency were evaluated in this study. The pulp mold samples were prepared with mixture ONP (Old news paper) and EFB by using laboratory wet pulp molder. The changes in the drying efficiency were measured with the changes in the solid contents of pulp mold samples during drying process. The efficiency of the surface coating treatment on the pulp mold depending on the condition of the pulp mold samples were also evaluated in order to improve the water resistance properties of pulp mold. The addition of EFB increased the drying efficiency by providing the bulkier structure and the higher water contact angle, which indicated the better water resistance properties. The water resistance were improved by the surface coating treatments and the application of surface coating on the pulp mold at the higher moisture contents resulted in the higher improvement in the water resistance. The bulkier structure originated from the application of EFB fiber reduced the effects of the surface coating, which could be overcome by the control of surface coating process.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.10-14
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• 2011

The electrode material performances of electric double layer capacitor(EDLC) were investigated using mesopous active carbon fiber(ACF), which was prepared by the iron exchange method. The mesoporous ACF had pore characteristics of specific surface area around 1249, 664 $m^2$/g, mesoporous fraction around 70.6-81.3% and meanpore size around 2.78-4.14 nm. The results showed that as HNO3 treatment time decreased, the specific surface area increased and mesoporous fraction decreased. To investigate electrochemical performance of EDLC, unit cell was manufactured using mesoporus ACF, conducting material and binder; organic elctrolyte was used on this experiment. The specific capacitance of ACF treated with HNO3 for 2 hours turned out to be 0.47 $F/cm^2$and the results of the cyclic charge-discharge tests were stable. Thus, the electrochemical performance of EDLC was mainly dependent on specific surface area of ACF electrode and the diffusion resistance of charge decreased as the mesopore increased.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.345-351
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• 2019

In this study, the hollow fibers from $TiO_2$ and various metal oxides additives were fabricated and characterized in order to remove the arsenic substance from a contaminated water. Experimental results showed the best arsenic adsorption performance from pristine $TiO_2$ hollow fibers. When metal oxides were added, the metal oxides reduced the acid sites on the surface of $TiO_2$ and the arsenic adsorption performance decreased. However, the long term arsenic adsorption performance was enhanced and showed better performance than that of using pristine $TiO_2$ hollow fibers when $Al_2O_3$ was added during the hollow fiber fabrication. In addition, the arsenic adsorption performance showed a high dependency on the specific surface area of hollow fibers. It was confirmed that the abundancy of Lewis and Bronsted acid sites provided was favorable for the arsenic adsorption. It was also demonstrated that commercially available $TiO_2$ powders can be an attractive candidate material for manufacturing hollow fibers for a small scale water treatment plant.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.224-224
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• 2012

For decades, carbon fiber has expanded their application fields from reinforced composites to energy storage and transfer technologies such as electrodes for super-capacitors and lithium ion batteries and gas diffusion layers for proton exchange membrane fuel cell. Especially in fuel cell, water repellency of gas diffusion layer has become very important property for preventing flooding which is induced by condensed water could damage the fuel cell performance. In this work, we fabricated superhydrophobic network of carbon fiber with high aspect ratio hair-like nanostructure by preferential oxygen plasma etching. Superhydrophobic carbon fiber surfaces were achieved by hydrophobic material coating with a siloxane-based hydrocarbon film, which increased the water contact angle from $147^{\circ}$ to $163^{\circ}$ and decreased the contact angle hysteresis from $71^{\circ}$ to below $5^{\circ}$, sufficient to cause droplet roll-off from the surface in millimeter scale water droplet deposition test. Also, we have explored that the condensation behavior (nucleation and growth) of water droplet on the superhydrophobic carbon fiber were significantly retarded due to the high-aspect-ratio nanostructures under super-saturated vapor conditions. It is implied that superhydrophobic carbon fiber can provide a passage for vapor or gas flow in wet environments such as a gas diffusion layer requiring the effective water removal in the operation of proton exchange membrane fuel cell. Moreover, such nanostructuring of carbon-based materials can be extended to carbon fiber, carbon black or carbon films for applications as a cathode in lithium batteries or carbon fiber composites.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.814-821
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• 1999

The specific capacitance characteristics of the electric double layer capacitors(ELDC) which were made of phenol based activated carbon fiber(ACF) electrodes. Also the effect of aqueous electrolytes on the cell performance has been investigated with respect to different specific surface areas of electrodes and different kinds of aqueous electrolytes. It has been shown that larger surface area and pore size, higher conductivity of electrodes, and higher ion mobility of electrolytes have better specific capacitances. It has been found that heat treatment at $1200^{\circ}C$ and $CO_2$ post-activation at $900^{\circ}C$ of the electrode are effective to improve the specific capacitance over 145F/g and 165F/g, respectively. The EDLC showed high efficiency and long cycle life over 30000 cycles.

• Composites Research
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• v.33 no.6
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• pp.395-400
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• 2020

In this paper, we manufactured silsesquiaznae (SSQZ)-coated carbon nanotube (CNT) surface heating elements, which allowed stable heating at high temperatures. The prepared composite sheet was confirmed by FE-SEM that the SSQZ fully coated the surface of CNT sheet. Furthermore, it was also confirmed that the silicon carbonitride (SiCN) ceramic formed by heat treatment of 800℃ have no defects found and maintain intact structure. The CNT/SiCN composite sheet was able to achieve higher thermal stability than raw CNT sheets in both nitrogen and air atmosphere. Finally, the CNT/SiCN composite sheet was possible to heat up at a temperature of over 700℃ in the atmosphere, and the re-heating was successfully operated after cooling.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.6-11
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• 2001

In order to use bast fibers of mulberry tree at a pulp source of Hanji, the bast fibers were microbiologically treated with several wood rot fungi, and the microscopic characteristics of bast fibers depending on treatment days were evaluated. By wood rot fungi, Phanerochaete chrysosporium and Trametes versicolor, the weight reduction ratio was approximately 50 percent within incubation for 20 days. occurring together with decomposition of useful fibers. However, Hwterobasidion insularis and Stereum hirsutum have completely decomposed the utmost layer of black blue colored bast fibers, and not caused the damage if fibers. Until incubation for 10 days, the cellulose content of vast fibers by Stereum hirsutum was 78.9 percent with lignin content of 7.2 percent, showing an appropriate decomposition for useful fibers. By microscopic observation, the bundled fibers were separated to single fiber within treatement days 30 by Pleurotus ostreatus, and there were no damage on the surface of fiber by treatment days 50.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.701-713
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• 1996

The purpose of this study was to evaluate the biocompatibility of the Nd:YAG lased root surface followed by root planing and/or tetracyline-HCI(T.C.-HCI) conditioning. $30,4mm{\times}4mm$ root segments were obtained from unerupted third molars and 21, periodontally involved root segments. The treatment groups were as follows : (1) healthy root cementum surface groups : 1) control(non-treated group), 2) lased only, 3) lased/root planed, and 4) lased/T.C.-HCI. (2) diseased root cementum surface groups : 1) control(root planed only), 2) lased/root planed, and 3) lased/root planed/T.C.-HCI. The specimens were treated with a Nd:YAG laser using a $320{\mu}m$ noncontact optic fiber handpiece with an energy setting of 1.5W($114.6J/cm^2$), 2.0W($152.9J/cm^2$), 5.0W($382J/cm^2$) for one minute. The fiber was held perpendicular to the petri dish(NUNC) 2cm apart in an attempt to expose the entire root segments equally. Human gingival fibroblasts were cultured from explants of normal interdental gingival tissue obtained during third morlar extraction. The attachment assay was performed with third-generation fibroblasts. The numbers of gingival fibroblasts attached to the root surface were counted on each specimen under the light microscope, and were statistically analyzed by the oneway ANOVA followed by Tukey's test in SPSS/PC+programs. The results were as follows : 1) In healthy root cementum surfaces, lased/root planed groups exhibited a significantly increased fibroblast attachment compared to controls, lased only, and lased/T.C.-HCI groups(p<0.05), 2) In diseased root cementum surfaces, laser treatment followed by root planing and/or T.C.HCl groups exhibited a increased tendency of fibroblast attachment compared to root planed only group. The results suggest that laser treatment followed by root planing and/or T.C.-HCl would appear necessary so as to render the root surface biocompatible.