• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.13-17
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• 1997

The densification of $Al_2$O$_3$/15v/o ZrO$_2$ (Zirconia Toughened Alumina: ZTA) to the 99% of theoretical density was attempted by controlling the processing parameters affecting the each processing step i.e., milling, spray-drying, forming and pressureless sintering. The ZTA processed under the identical conditions showed a large variation in the green and sintered densities, and the mechanical properties. The deviation of 4-point bending strength was more than 100MPa for the ZTA with ~99% of theoretical density. Moreover, the relative green and sintered densities were deviated greatly from the average value. This low reproducibility could be caused by the variation of spray-dried granule properties. Thus, the effect of yield strength and morphology of spray-dried ZTA granule on the green and sintered densities and the mechanical properties needs to be studied in detail. The objective of this work is to fine out the optimum condition of compaction pressure and compaction method depending on the properties of spray-dried granules.

• Korean Journal of Materials Research
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• v.14 no.10
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• pp.749-753
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• 2004

In this study, we attempt to synthesize the $Sr_{3}SiO_{5}:Eu$ yellow phosphor by sol-gel technique. Based on the blue emitting diodes as primary light source, white light emitting diodes have been manufactured using the $Sr_{3}SiO_{5}:Eu$ yellow phosphor as the luminescent material. Luminescent efficiency of yellow phosphor as well as that of blue LED is very important factor to enhance the luminescent efficiency of white LED. In order to improve the luminescent efficiency, we have synthesized the $Sr_{3}SiO_{5}:Eu$ phosphor by sol-gel technique. To research optimum condition of gelation reaction, the ratio of $H_{2}O$ to TEOS was fixed as 60:1. When the drying temperature was at $100^{\circ}C$, emission intensity was better than at $70^{\circ}C$. The critical $Eu^{2+}$ concentration was estimated to be about 0.05 mol and sintering temperature at $1300^{\circ}C$ was indicated best emission intensity.

• Korean Journal of Materials Research
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• v.11 no.9
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• pp.740-744
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• 2001

The $Y_2SiO_5:Ce$ phosphors were synthesized by sol-gel technique in order to improve the performance of blue emitting phosphors for field emission display(FED). The resulted$Y_2SiO_5:Ce$ phosphors enhanced the emission intensity. In addition, calcination temperature of sol-gel technique(1300~140$0^{\circ}C$) was lower than that of the solid state reaction(>1$600^{\circ}C$). Under 365 nm and low voltage electron excitations. $Ce^{3+}$ -activated $Y_2SiO_5$phosphors showed blue emission band with a range of 400~ 430nm. Especially, 2mol% $Ce^{3+}$ doped $Y_2SiO_5:Ce$phosphors showed the maximum emission intensity. We have also controlled drying temperature of wet gel, pH, and $H_2O$/TEOS molar ratio for the optimum condition of TEOS hydrolysis.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.564-568
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• 2006

AlO(OH) nano gel is used in precursor of ceramic material, coating material and catalyst. For use of these, not only physiochemical control for particle morphology, pore characteristic and peptization but also studies of synthetic method for preparation of advanced application products were required. In this study, AlO(OH) nano gel was prepared through the aging and drying process of aluminum hydroxides gel precipitated by the hydrolysis reaction of dilute NaOH solution and aluminum sulfate solution. In this process, optimum synthetic condition of AlO(OH) nano gel having excellent pore volume as studying the effect of water and aluminum sulfate mole ratio on gel precipitates has been studied. Water and aluminum sulfate mole ratio brought about numerous changes on crystal morphology, surface area, pore volume and pore size. Physiochemical properties were investigated as using XRD, TEM, TG/DTA, FT-IR, and $N_2$ BET method.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.17-22
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• 2008

Four kinds of leaves with different shapes of leaf blade were used as experimental materials to establish an optimum condition for treating leaves to obtain skeleton leaves. Effective concentration and length of soaking time in a hot NaOH solution, which resulted in high valued ornaments, were 60% (v/v) for 50 minutes for Acer buergerianum (palmatifid), 20% (v/v) for 50 minutes for Ilex cornuta (serrate), 20-60% (v/v) for 70 minutes for Quercus mongolia (lobed), and 20-40% (v/v) for 70 minutes for Quercus palustris (parted). Through a series of the process of soaking leaves in a hot NaOH solution, rinsing or brushing to remove mesophyll, drying, and dying, high quality ornaments could be obtained.

• Journal of the Korea Institute of Building Construction
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• v.6 no.1 s.19
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• pp.101-107
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• 2006

While a Study with regard to the measurement on Concrete Strength and the Change of Drying Shrinkage in accordace with Content Ratio of Crushed Stone Powder, it is being analyzed as the result that the strength according to Content Ratio of crushed Stone Powder is somewhat lowering. Accordingly, it is the real situation that the Concrete mixed with Crushed Stone Powder is utilized for non-structural material, not for the structural material. Therefore, this Research willing to furnish the suitable utilizing scheme for construction site as well as practical life by means of conduct the experiment on both Concrete Pressure Strength according to mixture with Crushed Stone Powder and Elastic Modulus, it also presumes the optimum Elastic Modulus Equation after analysis of comparison with common concrete strength. As the result of the experiment, in case of the Content Ratio of Crushed Stone Powder is less than 5%, it did not display a big difference in its both strength and matter-property compare with common concrete. In case of Elastic Modulus, when the Pressure Strength is 50% and 40% respectively, the Elastic Modulus Equation accords very well with the provided condition of Quadratic function, and as the result of the Presumption on Elastic Modulus according to Content of Crushed Stone Powder, in case the Pressure Strength is 50%, Elastic Modulus Equation showed that Error Ratio of Cubic function is at degree of 0.0005%, in case the Pressure Strength is 40%, Elastic Modulus Equation was accorded well with the value of the experimental data likely as the Error Ratio of Cubic function is at the degree around 0.0034%, respectively.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.103-108
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• 2019

This study was conducted to select the optimal extraction method of codonopsis lanceolata saponin. To investigate the lancemasides content depending on each extraction method, various extractions were performed: reflux (methanol and butanol), hot water, as well as ultrasonic bath (40 kHz; continuous irradiation/interval irradiation) and ultrasonicator (20 kHz) extractions. From the result, the overall lancemasides content were the highest in ultrasonic bath (MeOH; continuous irradiation) extraction, followed by ultrasonic bath (water; continuous irradiation)>ultrasonic bath (MeOH; interval irradiation)>ultrasonicator (MeOH)>hot water>MeOH reflux>BuOH reflux extractions in that order. Sample drying method prior to ultrasonic bath extraction was more effective shade drying than freeze drying. Effective duration and temperature of extraction was 2 hr at $64^{\circ}C$. And ingredient change diverted from aster saponin Hb to lancemasides was identified by extraction condition such as extraction time and temperature.

• Elastomers and Composites
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• v.42 no.2
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• pp.75-85
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• 2007

In this study, the new adhesion system was studied to improve the adhesion strength between polyester cord and rubber matrix. In order to enhance the adhesion strength through polyester cord's surface treatment, the NaOH solution was used. The NaOH solution concentrations of 0.03, 0.05, 0.1, 0.2, 0.5, 1 and 5 wt.% were used in surface modifying the polyester cord. The optimum condition showing the maximum adhesion strength of polyester cord with SBR compound containing bonding agent was at NaOH concentration of 0.05 wt.% with treatment time of 10 minutes. When the NaOH solution concentration was above 1 wt.%, the polyester cord due to the excess surface modification was damaged, and resulted in breakage during the adhesion test. Also, the adhesion strength between polyester and SBR could be improved by coating the polyester cord with triallylcyanurate(TC) adhesive. The drying condition of polyester cord coated with TC attributed to the adhesion strength. The maximum adhesion strength was obtained by using the polyester cord dried at $220^{\circ}C$ rather than dried at room temperature.

• Culinary science and hospitality research
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• v.13 no.2
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• pp.1-11
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• 2007

The process of Cheonggukjang powderization and application to the western food recipes were established. Cheonggukjang was made and processed into the powder. The optimum condition of Cheonggukjang solution for the powdering process was 50%(w/w). And it was completely grinded by a mixer. Drying condition of a spray dryer was to be injected 1 mL/sec. in $105^{\circ}C$ with 3,000 rpm. The components of Cheonggukjang were 49.7 g/100 g of moisture, 2.6 g/100 g of crude ash, 16.2 g/100 g of crude carbohydrate, 23.4 g/100 g of crude protein, 8.1 g/100 g of crude fat, and 9.3 g/100 g of cellulose. The major amino acid was glutamic acid and its quantity was 4,345.5 mg/100 g. And the next were aspartic acid (2,539.2 mg/100 g) and leucin (1,963.2 mg/100 g). In application, 4 kinds of soup recipes using Cheonggukjang powder were developed. The sensory test showed the acceptability between the soup with the powder and the soup without the powder was significant at odor(p<0.05) in vegetable cream soup and broccoli soup, and at taste(p<0.01) in vegetable cream soup. And the soup with non powder showed more acceptability.

• Culinary science and hospitality research
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• v.21 no.1
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• pp.77-89
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• 2015

The objective of this study was to optimize processing conditions for the production of an instant puffed rice product using response surface methodology (RSM) and contour analysis. Sensory and texture qualities, and physical properties of the puffed rice were analyzed with various processing conditions related to drying and puffing temperature, and moisture content. Preference, color intensity, cohesiveness, rehydration ratio, density and lightness of the puffed rice product significantly varied depending on the processing conditions. The responses showed high $R^2$ values (0.623, 0.852, 0.735, 0.688, and 0.790) and lack-of-fit. Rehydration ratio was found to have a negative correlation with density in the condition of drying and puffing temperature. Lightness and preference scores of the puffed rice increased as the moisture content increased. According to RSM, the preference scores were very highly related to the moisture content, and the optimum processing conditions of the puffed rice product were at $40^{\circ}C$ of drying temperature, with 11.0% of moisture content, and at $232.7^{\circ}C$ of puffing temperature.