• 한국기계가공학회지
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• 제6권1호
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• pp.13-19
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• 2007

The spring is an important mechanical parts to improve the functions of precision machines, automobiles, ships, industrial machines, and IT devices etc.. The hinge mechanism for LCD monitors is very important to support and maintain the proper position of monitor panel, and the tension spring which is a major parts of hinge mechanism plays a significant roll to provide the supporting force positioning the monitor panel. In this paper, an analysis and experiment were carried out to investigate the fatigue characteristics of the tension spring of hinge mechanism, such as hardness test, fatigue test and fractography analysis. As a result of this study the SWPB with heat treatment and shot peening was found to have the optimal design conditions of tension spring for LCD monitor hinge mechanism.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.281-286
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• 2001

Titanium alloy conducted in this experimental study has superior corrosive resistant and is mainly used in aerospace, automotive and petro-chemical industries. It is also treated with important materials of domestic goods due to improvement of the standard of living. In this study specimens were processed in the wire EDM after annealing, solution treatment and aging. Results were obtained through repeated experments of main rough process and finish process with the change of process parameters. Processing characteristics such as surface hardness, surfaces roughness, shape of processed surface and components were measured. The results confirmed that the above mentioned elements were improved in accordance with the number of process. Therefore, the optimal wire EDM condition in accord with processing characteristics is proposed in this experiment.

• 한국지역사회생활과학회지
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• 제15권1호
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• pp.27-33
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• 2004

Natural dyeing means coloring with dyes extracted from plants, minerals or animals found in nature. Natural dyeing provides calm and natural colors; it has antibacterial and deodorizing qualities; and the dyeing process is environmentally friendly. This study extracted natural dyes from young fruit by thinning out the superfluous fruits of Naju pear trees, and then examined its dyeing properties, the optimal dyeing conditions, and its color fastness for practical use. The results indicated that dyeing is ideal when it had Cu mordant treatment (5% concentration at 9$0^{\circ}C$, pH 4) for 50 min. The color fastness of natural dyes with Cu mordant treatment was very excellent after rubbing and dry cleaning, and also good after exposure to perspiration, light and washing.

• 한국기계가공학회지
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• 제8권4호
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• pp.104-109
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• 2009

In this paper, polymer nanocomposites were fabricated by mixing fire-resistant and high pseudoplastic Nylon 6,6 with MWNT(Multiwalled Nanotube), which has mechanical, electrical, and heat stable properties. The experiments were performed in order to investigate their mechanical and electrical properties depending on the level of MWNT and the presence of acid treatment on Nylon 6.6. Morphology of polymer nanocomposites was observed using Scanning Electron Microscopy technique. The results indicate that the polymer nanocomposites have the best mechanical and electrical properties in the optimal conditions of Nylon 6.6 and MWNT(10wt%).

• 한국염색가공학회지
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• 제13권2호
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• pp.7-7
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• 2001

This paper investigated the dyeability and surface color of silk and cotton fabrics dyed with chustnut bur extract. Some experiments were performed under the various dyeing conditions such as dyeing temperature, dyeing time, repetition of dyeing, dyeing pH, mordanting condition, washing fastness and light fastness with silk and cotton fabrics. The results obtained were as follows 1. △E value was increased when dyeing temperature and time was higher, value of munsell was shifted from Yellow to Yellow-Red at hither dyeing temperature and time in silk and cotton fabrics. 2. Optimal dyeing pH was increased with acidity of dyeing solution in silk and cotton fabrics, and repetition of dyeing did not change the dye-uptake. 3. When mordanting time and temperature was higher, △E value was larger in silk and cotton fabrics. Silk and cotton fabrics with Fe-premordanting treatment had best dyeability, but treatment with Sn-mordanting was worst. 4. Washing fastness and light fastness was excellent in various dyeing condition at silk fabric but cotton was without practical use.

• 한국염색가공학회지
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• 제13권2호
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• pp.93-103
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• 2001

This paper investigated the dyeability and surface color of silk and cotton fabrics deed with chustnut bur extract. Some experiments were performed under the various dyeing conditions such as dyeing temperature, dyeing time, repetition of dyeing, dyeing pH, mordanting condition, washing fastness and light fastness with silk and cotton fabrics. The results obtained were as follows 1. $\Delta{E}$ value was increased when dyeing temperature and time was higher, value of munsell was shifted from Yellow to Yellow-Red at hither dyeing temperature and time In silk and cotton fabrics. 2. Optimal dyeing pH was increased with acidity of dyeing solution in silk and cotton fabrics, and repetition of dyeing did not change the dye-uptake. 3. When mordanting time and temperature was higher, $\Delta{E}$ value was larger in silk and cotton fabrics. Silk and cotton fabrics with Fe-premordanting treatment had best dyeability, but treatment with Sn-mordanting was worst. 4. Washing fastness and light fastness was excellent in various dyeing condition at silk fabric but cotton was without practical use.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.296-299
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• 2000

The electrical properties of various metal phthalocyanine(MPc) thin film sensors were tested in the presence of $NO_x$ gas. Among the Phthalocyanine(Pc) thin films, lead phthalocyanine(PbPc) thin film showed the best results nd its sensitivity was over 80% at 5ppm of $NO_x$ gas. Optimal operating conditions including response time and cyclic treatment of $NO_x$ were tested and discussed.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.118-119
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• 2006

The development of Fe-based metal matrix composites (MMCs) with high content of hard phase has been approached by combining the use of advanced powder metallurgy techniques like high-energy milling (HEM), cold isostatic pressing (CIP) and vacuum sinterings. A 30% vol. of NbC particles was mixed with Fe powder by HEM in a planetary mill during 10h, characteristing the powder by the observation of morphology and microstructure by scanning electron microscopy (SEM). After of sintering process the variation of density, hardness,carbon content and the microstructural changes observed, permits to find the optimal conditions of processing. Afterwards, a heat treatment study was performed to study the hardenability of the composite.

• Preventive Nutrition and Food Science
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• 제16권4호
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• pp.357-363
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• 2011

Recently, we found that Arthrobacter crystallopoietes N-08 isolated from soil directly produces trehalose from maltose by a resting cell reaction. In this study, the optimal set of conditions and substrate specificity for the trehalose production using resting cells was investigated. Optimum temperature and pH of the resting cell reaction were $55^{\circ}C$ and pH 5.5, respectively, and the reaction was stable for two hours at $37{\sim}55^{\circ}C$ and for one hour at the wide pH ranges of 3~9. Various disaccharide substrates with different glycosidic linkages, such as maltose, isomaltose, cellobiose, nigerose, sophorose, and laminaribiose, were converted into trehalose-like spots in thin layer chromatography (TLC). These results indicated broad substrate specificity of this reaction and the possibility that cellobiose could be converted into other trehalose anomers such as ${\alpha},{\beta}$- and ${\beta},{\beta}$-trehalose. Therefore, the product after the resting cell reaction with cellobiose was purified by ${\beta}$-glucosidase treatment and Dowex-1 ($OH^-$) column chromatography and its structure was analyzed. Component sugar and methylation analyses indicated that this cellobiose-conversion product was composed of only non-reducing terminal glucopyranoside. MALDI-TOF and ESI-MS/MS analyses suggested that this oligosaccharide contained a non-reducing disaccharide unit with a 1,1-glucosidic linkage. When this disaccharide was analyzed by $^1H$-NMR and $^{13}C$-NMR, it gave the same signals with ${\alpha}$-D-glucopyranosyl-(1,1)-${\alpha}$-D-glucopyranoside. These results suggest that cellobiose can be converted to ${\alpha},{\alpha}$-trehalose by the resting cells of A. crystallopoietes N-08.

• 한국식생활문화학회지
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• 제34권5호
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• pp.637-644
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• 2019

The purpose of this study was to optimize the mandarin dry chip manufacturing using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the drying temperature ($X_1$, $50-90^{\circ}C$), drying time ($X_2$, 12-36 hours), and microwave pretreat time ($X_3$, 0-4 minutes). The results of appearance ($Y_5$), color ($Y_6$), taste ($Y_8$) and overall acceptance ($Y_{10}$) were fitted to the response surface methodology model ($R^2=0.86$, 0.88, 0.89, and 0.84, respectively). Increasing the drying temperature and microwave treatment time were negatively evaluated for consumer acceptance. On the other hand, a high value of consumer acceptance was evaluated when the drying time was more than 24 hr. Therefore, the optimal conditions of $X_1$, $X_2$, and $X_3$ were $52.989^{\circ}C$, 24 hr, and 1 min, respectively. Under these optimal conditions, the predicted values of $Y_5$, $Y_6$, $Y_8$, and $Y_{10}$ were 5.066, 5.338, 5.063, and 5.339, respectively.