• Corrosion Science and Technology
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• v.18 no.1
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• pp.16-23
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• 2019

Steels for automotive fuel tank require unique properties such as corrosion resistance for fuel, welding for joining, forming for press, and painting for exterior. Recently, automakers have been requiring excellent seam weldable steels to enhance manufacturing productivity of fuel tank. Thus, POSCO developed a new type of functional steels coated with nano-composite thin layer on Zn-Ni plating steels. The nano-composite coating solution was prepared by mechanical fine dispersion of solutions consisting of polymeric resin and nano-composite materials in aqueous media. The composite solution was coated on the plating steel surface by using roll coater and cured through induction furnace. These new developed plating steels were evaluated for quality performances such as seam and spot weldability, press formability, and corrosion resistance. These new functional steels coated with nano-composite layer exhibited excellent seam weldability and press formability. Detailed discussion of coating solution and experimental results suggest that nano-sized composite dispersion as coating layer plays a key role in enhancing the quality performance.

• Journal of Korean Dental Science
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• v.17 no.2
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• pp.84-91
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• 2024

Achieving both esthetic and functional implant rehabilitation is crucial for the successful treatment of the anterior maxilla. Adequate peri-implant alveolar bone and soft tissue are essential for optimal rehabilitation of the esthetic area, and there is a direct association between the implant position and prosthetic outcomes. Immediate provisionalization may also be advantageous when combined with augmentation. This case report described the implant placement in a 25-year-old female patient who had lost her right maxillary lateral incisor (#12) due to trauma-induced avulsion. The treatment involved simultaneous grafting and collagenated, deproteinized bovine bone mineral, along with subepithelial connective tissue taken from the right maxillary tuberosity. A polyetheretherketone abutment and non-functional immediate provisionalization were performed by removing both the proximal and occlusal contacts on the composite resin crown. Clinical and radiographic evaluations revealed maintenance of stable ridge contour aspects for six months following surgical treatment. In summary, implant rehabilitation in the esthetic zone can be successful using simultaneous soft and hard tissue grafts. Moreover, soft tissue stabilization post-subepithelial connective tissue grafting can be achieved through early or immediate visualization, along with immediate implant placement.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.44-49
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• 2011

The bio-degradable transplanting pot containing rice by-product (rice-hull and rice-bran) were developed, and tested their ability for agronomic use. Rice by-products were crosslinked with biodegradable aliphatic ally aromatic copolyesters or urea resin for making transplanting pot. Mechanical properties and degradability of these pots were measured and compared to those of the Jiffy pot (commercially used bio-degradable pot). Mechanical strength was higher than that of Jippy pot, and bio-degradability was excellent under the actual field condition. In addition, the pot could be degraded within 3 months under the ground. Our result indicated bio-degradable pot containing rice by-products has a great potential for such agronomic use.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.976-980
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• 2010

A series of arylacetylene resins with siloxane units were synthesized by the condensation reactions of m-diethynylbenzene magnesium reagents with various $\alpha,\omega$-bis(chloro)dimethylsiloxanes. These resins are liquids and are miscible with common organic solvents at room temperature. The structures of the resins were characterized by FT-IR, $^1H$ NMR, $^{13}C$ NMR, $^{29}Si$ NMR, and gel permeation chromatography (GPC). The thermal behaviors of the resins were examined with differential scanning calorimetry (DSC). These resins have good processability. They can be thermally cross-linked through the ethynyl groups to produce cured resins. The thermal and thermooxidative stabilities of the cured resins were studied by thermogravimetric analysis (TGA). The cured resins possess high thermal and thermooxidative stability. Their decomposition occurs at above $500^{\circ}C$ in both $N_2$ and air. With increasing the length of siloxane units in the resins, the thermal stability of the cured resins decreases in $N_2$. When the cured resins were sintered above $1450^{\circ}C$ under argon, hard and glassy SiOC ceramics were obtained. These SiOC ceramics have the decomposition temperatures at 5% weight loss above $800^{\circ}C$ in air.

• Analytical Science and Technology
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• v.13 no.3
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• pp.323-331
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• 2000

Two chelating resins, XAD-16-TAC and XAD-16-TAO were synthesized by Amberlite XAD-16 macroreticular resin with 2-(2-thiazolylazo)-p-cresol (TAC) and 4-(2-thiazolylazo)-orcinol (TAO) as functional groups. The sorption behaviour of Zr(IV), Th(IV) and U(VI) with two chelating resins were examined with respect to the effect of pH and masking agent by batch methods. It was obtained that the optimum pH was in the range of 5-6, and two chelating resins showed good separation efficiency of Zr(IV) or Th(IV) by using $NH_4F$ as a masking agent. Characteristics of desorption were investigated with 0.1-2 M $HNO_3$ as desorption agent. It was found that 2 M $HNO_3$ showed high desorption efficiency to most of metal ions except Zr(IV). XAD-16-TAC resin is applied to separation and preconcentration of trace Zr(IV) from mixed metal ions. Also, Th(IV) ion can be successfully separated from U(VI) and Zr(IV) ion by using XAD-16- TAO resin.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.840-845
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• 2011

Degradation products of agarose are biologically active and thus used as an ingredient in pharmaceuticals or functional cosmetics. Furthermore, it has been strongly considered as a substrate for bio-ethanol fermentation. Recently, we isolated new agarase-producing microorganism, Pseudoalteromonas sp. from south sea of Korea. In this study, we aimed to separate and purify the agarase from culture broth of this strain. Separation of agarase was performed by ion- exchange chromatography on DEAE-Sepharose resin. Equilibrium pH and volume ratio of resin to the amount of protein were optimized for the efficient adsorption of protein. 410 ${\mu}g$ of protein was completely adsorbed to 3 mL of resin at pH 7.5. The total amount of eluted protein increased as NaCl concentration increased to 400 mM at isocratic elution. Agarase was separated by linear gradient elution of NaCl (0~1,000 mM). Three major protein peaks were observed and the presence or absence of agarase in these eluted proteins was measured by Lugol's staining technique. Only six eluted protein fractions showed strong agarase activity.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.79-89
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• 2019

The field measurement and laboratory experiment were conducted to investigate the effect of reducing the surface temperature of the functional aspect of the heat island phenomenon of the permeable block which is made the recycled synthetic resin rather than the existing concrete permeable block. Field measurement was taken for 3 days in consideration of dry condition and wet condition and laboratory experiment was divided into dry condition, rainfall simulating condition, and wetting condition. The variations of temperature and the evaporation rate of water moisture content after experiment were confirmed. As a result of field measurement, it is confirmed that the surface temperature decreases due to the difference in albedo of the pore block surface rather than the cooling effect due to the latent heat of vaporization. The evaporation of moisture in a dry state where drought persisted or a certain level of moisture was not maintained in the surface layer. As a result of laboratory experiment, resin permeable block gives higher surface temperature when it is dry condition than concrete permeable block, but the evaporation of water in the pore is kept constant by capillary force in rainfall simulation condition, and higher temperature reduction rate. As a result of measuring the evaporation rate after laboratory experiment, it is confirmed that the effect of reducing temperature is increased as the evaporation rate of water is higher. Based on these results, correlation formula for evaporation rate and temperature reduction rate is derived.

• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.109-115
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• 2009

The gene encoding a putative aspartate aminotransferase in Xanthomonas oryzae pv. oryzae (Xoo) was cloned using PCR technique. The gene was ligated with pET-21(a) vector containing His6 tag and expressed in E. coli BL21(DE3). Affinity purification of the recombinant aspartate aminotransferase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 43 kDa, as expected. The enzyme was the most active toward L-aspartate as an amino donor, indicating that the purified enzyme is one of aspartate aminotrans-ferases exist in Xoo. Optimal activity of the enzyme was observed at around pH 7.5 and stability was much higher at alkaline pH rather than acidic pH values. The enzyme was considerably activated by the presence of manganese ion, showing about 157% of control activity at 1.0 mM.

• Journal of dental hygiene science
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• v.22 no.1
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• pp.44-50
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• 2022

Background: This study compares and analyzes the degree of oral health information literacy by 25% for upper and lower grades to assess how differences in mothers' oral health information literacy affect infants' oral health behavior. Methods: The study surveyed 201 mothers with infants and children using a 36 question survey tool. Cross-analysis was conducted to determine the difference in oral health information literacy between the upper and the lower 25%. Results: Comparing 25% of the upper and lower grades of verbal oral health information literacy scores, the word with the most significant difference in the correct answer was resin. An item asking about the time to eat after fluoride varnish application showed the most significant difference in the correct answer on the functional oral health information literacy scale. Mothers' oral and functional oral health information literacy scores showed that verbal literacy was statistically significant for brushing guidance after children's meals, brushing guidance before children's bedtime, food intake restrictions before bedtime, and restrictions on consumption of cavity-inducing foods (p<0.05). Functional literacy was statistically significant in the post-brushing test of children and the correct brushing method map items (p<0.05). Conclusion: As a result of comparing and analyzing the upper and lower 25% of the mother's oral health information literacy, it was found that the mother's oral health information literacy affected the infant's oral health behavior. Therefore, systematic education is needed to raise literacy by grasping the level of oral health information literacy of mothers, and oral health education by level according to oral health information literacy should be developed.

• Carbon letters
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• v.19
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• pp.32-39
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• 2016

In this work, we studied the effects of electrochemical oxidation treatments of carbon fibers (CFs) on interfacial adhesion between CF and epoxy resin with various current densities. The surface morphologies and properties of the CFs before and after electrochemical-oxidation-treatment were characterized using field emission scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and single-fiber contact angle. The mechanical interfacial shear strength of the CFs/epoxy matrix composites was investigated by using a micro-bond method. From the results, electrochemical oxidation treatment introduced oxygen functional groups and increased roughness on the fiber surface. The mechanical interfacial adhesion strength also showed higher values than that of an untreated CF-reinforced composite.