• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.25-30
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• 2009

In this study, we synthesized novel UV-curable binders and applied for negative photoresist of display device. First, we synthesized UV-curable binders by radical polymerization with a mixture of Styrene/Methyl methacrylate/Methacrylic acid/Glycidyl methacrylate/N-Cyclohexylmaleimide at a fixed composition. Following the first step, we prepared a negative photoresist mixture optimized with photo sensitive initiator and others for the litho test. And then, we studied resolution and film retention with molecular weight of each binders and numerical value of Alkaline Desolution Rate(ADR). As a result of the litho test, we found that if the novel polymers have same numerical value of ADR, the resolution decreased and the film retention increased with the increasing of molecular weight of photoresist binder.

• Geotechnical Engineering
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• v.12 no.4
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• pp.115-130
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• 1996

The definition of laterite or lateritic soils is discussed on a climatic condition of tropical and semitropical regions, and the weathering index is indicated by the chemical composition. The chemical composition of$(Fe_2O_3+Al_2O_3)$ of the weathered granite residual soils in tropical and the temperate regions which shelus laterization usually ranges from 0.2 to 0.5. This study shows that the chemical ratio of the Chonju Ajung site is about 0.2U, and that of the regions along the shore of the western sea of Hongsong and Taechon is about 0.33. The chemical ratio of the non-laterite is less than 0.2, and the Kyougju Pulguksa site confirmed about 0.17, The X-Ray diffraction test shows that the clay mineral of the laterite soils is made of kaolinite, this X -Ray result indicates the same characteristics compared with the wrathered granite residual soils of other sites.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.2
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• pp.160-171
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• 2013

$LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ powder for cathode materials in lithium rechargeable batteries was treated by atmospheric plasma containing hydrogen to investigate the relationship between charge/discharge performance and physical/chemical changes of materials. Hydrogen plasma at atmosphere pressure was irradiated on the surface of active materials, and the change for their crystal structure, surface morphology, and chemical composition were observed by XRD, SEM-EDS and titration method, respectively. The crystal structure and surface morphology of $H_2$ plasma-treated powders were not changed but their chemical compositions were slightly varied. For charge/discharge test, $H_2$ plasma affected initial capacity and rate capability of active materials but continuous cycling was not subject to plasma treatment. Therefore, it was observed that $H_2$ plasma treatment affected the surface of materials and caused the change of chemical composition.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.107-116
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• 2013

PURPOSES: The liquid-type chemical warm-mix asphalt (WMA) additive has been developed. This study evaluates the basic properties of the additive and the mechanical properties of WMA asphalt and mixture manufactured by using the newly developed chemical additive. METHODS: First, the newly developed WMA additive was applied to the original asphalt by various composition of additive components and dosage ratio of additive. These WMA asphalt binders were evaluated in terms of penetration, softening point, rotational viscosity, and PG grade. Based on the binder test results, one best candidate was chosen to apply to the mixture and then the mechanical properties of WMA mixture were evaluated for moisture susceptibility, dynamic modulus, and rutting and fatigue resistance. RESULTS : According to the binder test, WMA asphalt binders showed the similar properties to the original asphalt binder except the penetraion index of WMA additive was a little higher than original binder. From the Superpave mix design, the optimum asphalt content and volumetric properties of WMA mixture were almost the same with those of hot mix asphalt (HMA) mixture even though the production and compaction temperatures were $30^{\circ}C$ lower for the WMA mixture. From the first set of performance evaluation, it was found that the WMA mixture would have some problem in moisture susceptibility. The additive was modified to improve the resistance to moisture and the second set of performance evaluation showed that the WMA mixture with modified chemical additive would have the similar performance to HMA mixture. CONCLUSIONS : Based on the various laboratory tests, it was concluded that the newly developed chemical WMA additve could be successfully used to produce the WMA mixture with the comparable performance to the HMA mixture. These laboratory evaluations should be confirmed by applying this additive to the field and monitoring the long-term performance of the pavement, which are scheduled in the near future.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.117-126
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• 2005

The chemical property analysis on the deposited clay using scanning electron microscope and energy dispersive x-ray spectrometer were performed. Also, the triaxial compression tests and consolidation tests using NaCl aqueous solution and leachate as substitute pore (or saturated) water in samples were carried out to find out the behaviour characteristics of strength and deformation of contaminated deposited clay. from the chemical composition analysis results of clay samples, the magnitudes of composition ratio were revealed in the order of O, C, Si, Al, and Fe. Of these, why the ratio of carbon appeared to be large is estimated as due to the increase of the phyto-planktons after the construction of tide embankment. In the triaxial compression test and consolidation test results, the shear strength and compression properties have increased with the increase in concentration of contaminant (NaCl). This phenomenon is considered as to be caused by the changes of soil structure to flocculent structure owing to the decrease in the thickness of diffuse double layer in proportion to increase in the concentration of electrolyte.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.526-532
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• 2006

The aim of this study was to evaluate the chemical composition, in vitro DM degradability, ME and OMD of alfalfa-maize silage mixtures in comparison to pure maize and alfalfa silages, and to test the existence of associative effects of ensiling alfalfa forage with whole-crop maize using the in vitro gas production technique. Ensiling alfalfa with whole-crop maize had a significant (p<0.001) effect on chemical composition, pH, in vitro DM degradability, OMD and estimated ME values of mixtures. DM content of the resultant silages significantly increased with increasing proportion of whole-crop maize in the mixtures, whereas the pH value, crude protein (CP), acid detergent fibre (ADF) and ash contents of mixtures decreased due to the dilution effect of whole-crop maize which was low in CP, ADF and ash. The pH values of all alfalfa-maize silage mixtures were at the desired level for quality silage. Gas production of alfalfa-maize silage mixtures at all incubation times except 12 h increased with increasing proportion of whole-crop maize. When alfalfa was mixed with whole-crop maize in the ratio 40:60, ME and OMD values were significantly (p<0.001) higher than other silages. Maximum gas production ($A_{gas}$) ranged from 65.7 to 78.1 with alfalfa silage showing the lowest maximum gas production. The results obtained in this study clearly showed that maximum gas production increased with increased percentage of whole-crop maize in the silage mixtures (r = 0.940, p<0.001). It was concluded that ensiling alfalfa with whole-crop maize improved the pH, OMD and ME values. However, trials with animals are required to see how these differences in silage mixtures affect animal performance.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.832-840
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• 2014

This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures ($5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$) and four durations (0, 1, 2, and 3 d) were arranged in a $4{\times}4$ factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as $25^{\circ}C$ and $35^{\circ}C$. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds $35^{\circ}C$, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above $35^{\circ}C$ during summer.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.74-79
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• 2008

The aim of this study was to analyze the chemical composition of 14 kinds of citrus oils and to test their biological activities. Citrus essential oils were obtained by steam distillation from immature fruits collected from Jeju Island and were analyzed using gas chromatograph (GC)-flame ionization detectors (FID) and GC-MS. Limonene (55.4% to 91.7%), myrcene (2.1% to 32.1%), ${\alpha}$-pinene (0.6% to 1.6%) and linalool (0.4% to 6.9%) were the major components in most citrus species. To evaluate in vitro antibacterial activity, all essential oils were tested against Propionibacterium acnes and Staphylococcus epidermidis. Nine out of fourteen citrus oils exhibited antibacterial activity against P. acnes, but not against S. epidermidis. The effects of the citrus oils on DPPH radical scavenging, superoxide radical anion scavenging, nitric oxide radical, and cytotoxicity were also assessed. Three essential citrus oils, Joadeung, Dongjunggyul, and Bujiwha, exhibited potent inhibitory effects on nitric oxide production. Two essential oils, Dongjunggyul and Joadeung, showed potent free radical scavenging activities in the DPPH assay. For future applications in cosmetic products, we also performed MTT assays in a human dermal fibroblast cell line. The majority of the essential oils showed no cytotoxicity. The results indicate that citrus essential oils can be useful natural agents for cosmetic application.

• Membrane Journal
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• v.25 no.1
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• pp.48-59
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• 2015

This paper reports a fabrication of poly(L-lactic acid) (PLLA) scaffold membranes through phase separation process using pure and mixed solvents. Chloroform and 1,4-dioxane were used as pure solvents and mixed solvents were obtained by mixing the pure solvents together. Morphologies, mechanical properties and mass transfer characteristics of the scaffold membranes were investigated through SEM, stress-strain test and glucose diffusion test. Scaffold membranes from the solution with pure chloroform showed solid-wall pore structure. In contrast, nano-fibrous membranes were fabricated from the solution with pure 1,4-dioxane. In case of mixed solvents, the scaffold membranes showed various structures with changing composition of the solvents. When 1,4-dioxane content was lower than 20 wt% in the solvent, scaffold membrane showed solid-wall pore structure. When the content was 20 wt%, scaffold membranes with macropores with the maximum size of $100{\mu}m$ was obtained. In the concentration range of 1,4-dioxane over 25 wt%, the scaffold membranes showed nano-fibrous structures. In this range, the fibers showed different diameters with changing composition of the solvent. The minimum fiber diameter was about $15{\mu}m$, when 1,4-dioxane composition was 80 wt%. These results indicate that the composition of the solvent showed a significant effect on the structure of scaffold membrane.

• Restorative Dentistry and Endodontics
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• v.43 no.3
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• pp.32.1-32.11
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• 2018

Objectives: This study evaluated the effects of a bleaching agent on the composition, mechanical properties, and surface topography of 6 conventional glass-ionomer cements (GICs) and one resin-modified GIC. Materials and Methods: For 3 days, the specimens were subjected to three 20-minute applications of a 37% $H_2O_2$-based bleaching agent and evaluated for water uptake (WTK), weight loss (WL), compressive strength (CS), and Knoop hardness number (KHN). Changes in surface topography and chemical element distribution were also analyzed by energy-dispersive X-ray spectroscopy and scanning electron microscopy. For statistical evaluation, the Kruskal-Wallis and Wilcoxon paired tests (${\alpha}=0.05$) were used to evaluate WTK and WL. CS specimens were subjected to 2-way analysis of variance (ANOVA) and the Tukey post hoc test (${\alpha}=0.05$), and KH was evaluated by one-way ANOVA, the Holm-Sidak post hoc test (${\alpha}=0.05$), and the t-test for independent samples (${\alpha}=0.05$). Results: The bleaching agent increased the WTK of Maxxion R, but did not affect the WL of any GICs. It had various effects on the CS, KHN, surface topography, and the chemical element distribution of the GICs. Conclusions: The bleaching agent with 37% $H_2O_2$ affected the mechanical and surface properties of GICs. The extent of the changes seemed to be dependent on exposure time and cement composition.