• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.266-271
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• 2007

The pH, acidity, color, reducing sugar, total sugar, alcohol, and organoletic characteristics of Takju containing puffed rice powder (0, 25, 50 and 75%) were investigated during fermentation for 10 days. After drastic decrease at Day 1, the pH increased gradually until Day 5 and then tended to decrease after Day 6. A lower concentration of puffed rice powder resulted in a greater pH reduction (p<0.05). Acidity increased quickly with days, especially for the 0% after Day 6 (p<0.05). After a sudden rise at Day 1, the Hunter ‘L’ value tended to decrease with days of fermentation. At the same day, the 75% showed the lowest Hunter ‘L’ value, however, it had the highest Hunter ‘a’ value except on Days 0, 3 and 10 (p<0.05). After a rapid reduction in reducing sugar on Day 3, no differences were observed in the samples (p<0.05). The 75% tended to be higher in reducing sugar. Total sugar decreased rapidly at Day 2, and then either remained unchanged or decreased after Day 3. With the exception of Day 4, the 75% had higher amounts of total sugar than the others at the same day (p<0.05). The Highest alcohol contents [13.0-16.4% (v/v)] occurred on Day 6. Higher alcohol concentrations were observed with higher puffed rice powder (p<0.05). In the sensory evaluation, no differences were detected between the 0% and those with puffed rice powder added (p<0.05).

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3078-3080
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• 2005

본 논문에서는 AF 기능을 구현함에 있어서 2 백만 화소 카메라 모듈인 Sharp LZ0P3731의 기능, AF 모터 (VCM, Voice Coil Motor)에 작용하는 힘과 구동원리, 이를 구동하기 위한 H/W의 설계 특성, 및 DM270을 이용한 AF 제어 시 Focus Value의 특성 분석을 바탕으로 Focus Value 특성을 고려한 최적 AF 알고리즘을 개발하였다. 본 논문에서 제안한 최적 AF 알고리즘은 '최대의 Focus Value가 각 State의 Step Value 마다 각각 다른 위치에서 검출'되는 AF 모터 및 구동 H/W특성을 고려하여, 최적 AF 기능은 최대의 AF Value에 근접하는 Lens Position 제어가 가능하도록 하였다. 이를 검증하기 위한 윈도우용 S/W로 성능을 확인한 결과, 일반적인 AF 기능은 58 프레임으로 3.87초의 시간이 소요되는 반면, 제안한 AF 기능은 25 프레임으로 1.67초로 2배 이상의 빠른 AF 성능을 가졌다.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.57-62
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• 1993

The influence of the storage temperature at $15^{\circ}C$ on the biochemical and structural changes in the red muscles (M. sternomandibularis) of korean native cattle postmortem were studied. The results obtained were summarized as follows; 1.5 to 2 hours postmortem the pH-value had dropped to $6.7{\sim}6.8$, after 18 or 20 hours at $15^{\circ}C$ it had reached its final pH-value (5.5). The irreversible loss of extensibility, i.e. the onset of rigor mortis, arose at $15^{\circ}C$ between 9 and 10 hours postmortem at pH 6.1 to 6.0 and R-value between 1.05/1.10. The complete loss of extensibility postmortem was reached after 18 to 20 hours at pH 5.5/5.6. Muscle and sarcomere length of korean native cattle were contracted about 20% and 15%, respectively at $15^{\circ}C$. Meat of korean native cattle had the highest shear force (4.7 kg) on 1 day after slaughter. The tenderness was increased with the ripening period prolonged and was highest at the end of the 9 day ripening period.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.305-314
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• 1989

Effect of pH variation in starting solution for the making of hydroxyapatite powder was studied in relation to the sinterability of the powder and their mechanical properties of the sintered hydroxyapatite ceramics. The sinterability of hydroxyapatite powder prepared at different pH was found to be improved with increase in pH value of the starting solutions. Thus the powders prepared from the higher pH solutions including 10.5, 11.0 and 11.5 could be well densified almost upto theoretical density by firing for 1 hr at 1,00$0^{\circ}C$. But the powder based on pH 10 exhibited less sinterability even being fired at much higher temperature of 1,10$0^{\circ}C$, it gave only 90-95% of theoretical density. On the other hand the powder prepared on the lowest pH value 9.5 could not be well densified and it could obtain only 78% of theoretical density even by firing at 1,30$0^{\circ}C$ for 1hr. It was found that prismatic crystals of whitlockite were always included in the sintered bodies based on the lower pH values as a minority crystalline phase together with the major crystalline phase of hydroxyapatite and its inclusion might impair the sinterability of powder. However in the case of the higher pH, the powder contained only hydroxyapatite as a crystalline phase on sintering without any minorities. The sphere shape of crystals might help effectively the densification of the bodies. The best mechanical properties could be obtained from the body of pH 11 sintered at 1,10$0^{\circ}C$, which gave 99.5% of theoretical density, 662Kg/$\textrm{mm}^2$ of vickers hardness and 1,352Kg/$\textrm{cm}^2$ of diameteral compression strength.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.123-128
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• 1989

An experiment was conducted to study the effect of frequency of defoliation on the ensiling characteristics and nutritive value of Guineaecotype 'A' (Panicum maximum Jacq) grass. Guinea grass harvested at 2, 3, 4, 5, 6, 7, 8, 9, 10 and 12-week cutting intervals was chopped (2 cm) and ensiled alone or with the addition of coconut (Cocos nucifera L.) meal (w/w-fresh weight basis), for periods of 6, 7 or 8 weeks in 2-litre laboratory silos. Dry matter, water soluble carbohydrates, lactic acid, pH, ash, nitrogen and digestibility in vitro were measured in representative samples of preensiled and ensiled material. Dry matter content of silages prepared from herbage harvested at 2 and 3 weeks intervals was lower (P<0.05) compared to longer defoliation intervals. The pH of silage prepared from herbage over 8 weeks old were higher (P<0.05) than those harvested below 8 weeks. The water soluble carbohydrate content of silage prepared from 3-weekly defoliated herbage was higher (P<0.05) than those prepared from longer periods. Lengthened growth period decreased (P<0.001) the crude protein content of the ensiled material, whereas the addition of coconut meal resulted in marginal increases. In vitro organic matter digestibility of the silages decreased (P<0.05) with the increase in forage maturity.

• Journal of the Korean Ceramic Society
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• v.32 no.10
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• pp.1123-1130
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• 1995

In the preparation of manganese zinc ferrite powders by alcoholic dehydration of citrate/formate solution. The effect of pH change on precipitation was investigated. The pH range for obtaining stable precipitates was studied. The glassy phase was obtained when the pH value of solution is higher than 5, and the formation mechanism of glassy phase was suggested. Below pH 5, the stable precipitates were formed, and the optimal pH was 2. Formation of glassy phase was accounted for the change of surface charge by pH change. The change of surface charge is caused by the interparticular agglomeration. The precipitate was redissolved into the water on the surface of precipitate itself and through the polymerization, it agglomerated. This mechanism is tought to be similar to that of viscous flow.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.692-701
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• 2020

This study evaluated the quality characteristics of crust derived from dry-aged Holstein and Hanwoo loins and their effects on food as additives. With respect to physicochemical properties, we examined the proximate composition, pH value, salinity, color, water and fat absorption, emulsifying capacity, and swelling yield. The protein and ash contents in the Holstein crust were significantly higher than those in the Hanwoo crust (p < 0.0001). The fat content in the Hanwoo crust was significantly higher than that in the Holstein crust (p < 0.01). The salinity, lightness, and yellowness of the Hanwoo crust were significantly lower than those of the Holstein crust (p < 0.001). Furthermore, the pH value and emulsifying capacity of the Hanwoo crust were significantly higher than those of the Holstein crust (p < 0.001). The fat absorption of the Holstein crust was significantly higher than that of the Hanwoo crust (p < 0.001). The swelling yield of the Holstein crust was significantly higher than that of the Hanwoo crust at pH 3 and 4 (p < 0.001), whereas the swelling yield of the Hanwoo crust was significantly higher than that of the Holstein crust at pH 7 (p < 0.001). Principal component analysis of dry-aged Hanwoo, Holstein, and non-aged Holstein showed different flavor patterns for each sample. Finally, the results showed that the crusts derived from dry-aged Hanwoo and Holstein loins were suitable flavor enhancers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.163-170
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• 1992

Color of kimchi juice was measured instrumentally to evaluate the quality of Korean cabbage kimchi during fermentation at 4$^{\circ}C$ and 16$^{\circ}C$ . These results were compared with those of chemical analyses of kimchi juice and sensory evaluation for kimchi. Chemiral analyses and sensory evaluation showed that the kimchi has reached pH 4.3, the pH value under an optimum ripening period, after 3-days fermentation at 16$^{\circ}C$ with almost the highest contents of vitamin C and carotenoids as well as desirable sour taste and texture. At 4$^{\circ}C$ the kimchi was unripened after 6-days fermentation. At 16$^{\circ}C$, $L^{*}$ value of kimchi juice did not show any significant change during fermentation periods. However, $a^{*}$ value increased until day 4$^{\circ}C$ and thereafter decreased sharply. $b^{*}$ value increased until day 3 and then showed no change. High correlations were seen between volume of kimchi juice, pH, total acidity and $L^{*}$or $b^{*}$ value, and between carotenoid content and $a^{*}$ value, respectively. It was desirable to use color $a^{*}$ or $b^{*}$ value of kimchi juice to evaluate the quality of kimchi. The kimchi was under an over-ripening period when $a^{*}$ value was equal to or lower than the initial value, or when $b^{*}$ value was almost constant. Predicting an optimum ripening period was possible by using a proportional value of $a^{*/}$ $b^{*}$ , i.e., unripening period, 1 $\geq$ and near 1 ; optimum ripening period, near 0.8 ; over-ripening period, < 0.8.eriod, < 0.8.d, < 0.8.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.49-57
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• 2002

This study was conducted to find out buffer capacities of forest soils by the treatment of simulated acid rain(SAR) of four forests(Q. spp., P. rigida, P. koraiensis, L. leptolepis) in Kyunghee university's practice forest. All soils of each forest stand were treated by simulated acid rain at the level of pH 3.0, 4.0, 5.0 respectively. The result obtained from this study can be summarized as follows: Soil pH was measured by soil depth of each forest stand. The deeper soil depth was, the higher soil pH was. Also it was appeared that base saturation of sample soils was the highest as 17.42% in P. rigida stand and cation exchange capacity(C.E.C) was the highest as 29.87 me/100 g in Q. spp. stand. for responses of soil leachates to acidification treatment with pH 3.0 simulated acid rain(SAR), as simulated acid rain(SAR)-input was increased, pH value of soil leachates appeared high temporarily, but soon pH value of soil leachates had been low gradually. At the rest of pH 4.0, pH 5.0 treatment, pH value of soil leachates was high proportionably. The amounts of TBC of primary stage had a difference as pH level of simulated acid rain and forest stands. But as simulated acid rain(SAR)-input was increased. Amount of TBC was diminished. Also the amounts of TBC of primary stage in acidification treatment with pH 3.0, 4.0 simulated acid rain(SAR) was higher that of acidification treatment with pH 5.0 simulated acid rain(SAR). These trend showed obvious difference at low soil acidity and high TBC. The amounts of activity Al of primary stage appeared high as increasing the input acidity of simulated acid rain(SAR). Also, by soil depth, the amounts of Activity Al was different between A layer(0-15 cm) and AB layer(0-30 cm). There was considerable the correlation between simulated acid rain-input and activity Al change. But this was oppositional trend in soil leachates of pH 4.0, 5.0 treatment and total base cations(TBC).

• Textile Coloration and Finishing
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• v.31 no.4
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• pp.249-257
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• 2019

Baker's yeast(Saccharomyces cerevisiae) was used as a biocatalyst for eco-friendly indigo dyeing and the reducing power of yeast according to the alkaline solution type was compared. NaOH solution, lye, and buffer solution were used as alkaline solutions. The reducing power(K/S value, oxidation/reduction potential(ORP), pH) was monitored according to the elapsed time including the initiation of reduction, peak reduction, and the end of reduction. In all alkaline solutions, it was confirmed that yeast can be used reducing agent in indigo reduction dyeing. The pH stability and reducing power of buffer solution was better than that of NaOH alone. Although, pH and ORP stability of the reduction bath in lye were better than that of buffer solution, K/S value in buffer solution was higher compared to lye. The reducing power was different depending on the starting pH of the dye bath, and it was better when starting at pH 10.70 than at pH 11.30. Fastnesses to washing, rubbing, and light were relatively good with above rating 4. There was no significant difference in colorfastness depending on the type of alkaline solutions.