• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.177-180
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• 2005

We have investigated electro-optical characteristics in three kinds of TN cells on the polyimide surface. Transmittance of no thermal stressed TN cells were better than that of thermal stressed TN cells. Also. the threshold voltage and the response time of thermal stressed TN cells were same that of no thermal stressed TN cells. There were little change of value in these TN cells. On the other hand. transmittances of TN cells on the polyimide surface decreased by increasing thermal stress time. Moreover. the residual DC of the thermal stressed TN cells on the polyimide surface showed the characteristics of thermal stressed TN cells were weakened as increasing thermal stress temperature and time. Therefore. thermal stability of TN cells were decreased gradually by giving high thermal stress for a long time.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.31-38
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• 2010

Extraction efficiency of colorants from red bean and black bean seed coat and its storage stability were examined according to the various extracting and storage conditions in this study. The obtained results were as follows ; The absorbance values of extracted colorants were increased with increasing extract time and temperature. pH 4 extracting was most efficient among the various pH conditions. The absorbance values of extracted colorant from red bean were increased with increasing extract time and temperature, when the extraction process was kept at $30^{\circ}C$ and $50^{\circ}C$, but it were decreased with increasing extract time at $70^{\circ}C$. In the case of black bean, it were also increased with increasing extract time and temperature. pH 5 extract was most efficient among the various pH conditions. In juice extractor system from red bean, the pH 5 of the pre-treatment was more efficient than the distilled water of pre-treatment. In black beans of the short-term pre-treatment with distilled water, the colorant was extracted better than at pH 5, but above 4 hours pre-treatment was decrease in pH 5. The Methionine added as a stabilizer gave the more effect to the stability of colorant from red bean the more Methionine addition. In the case of black bean 10mmol addition of methionine was more efficient than 20mmol.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.261-265
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• 1997

To know the availability of double fractionated palm olein (DFPL) for vegetable oil in commercial mayonnaise preparation, oxidative stability and stability to cold test of DFPL, soybean oil and blended oils (blended soybean oil with DFPL) were tested. Mayonnaises with these oils were prepared and then emulsion stability at low temperature $(-5^{\circ}C)$ were compared. The oxidative stability of vegetable oil by Rancimat test showed that induction time of DFPL (26.9 hr) was longer when compared with soybean oil (13.4 hr), and became longer with increase of DFPL ratio in the blended oil. Emulsion stability of mayonnaises at low temperature $(-5^{\circ}C)$ was decreased with the increase of DFPL ratio in the blended oil. But, mayonnaise with blended oil of below 20% DFPL was comparable to that with soybean oil only. Among quality characteristics of mayonnaises with soybean oil and blended oil (soybean oil 85% plus DFPL 15%) the latter showed stronger oxidative stability and less flavor reversion during high temperature treatment. This result suggested that the possibility of DFPL to substitute for vegetable oil in the preparation of commercial mayonnaise.

• Journal of Ginseng Research
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• v.7 no.2
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• pp.156-162
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• 1983

Stability of nitrogen compounds in the water-extract of ginseng has been investigated in terms of concentration and SDS-PAGE protein pattern as functions of times and temperature. The concentration of free amino-nitrogen in the extract of fresh ginseng varied with time at various temperatures. Especially at temperature over 90$^{\circ}C$, it showed a tendency of steady declease at a considerably fast rate. In the case of red ginseng which had been commercially processed and stocked for 1-7 years, it was found that the free amino-N concentration diminished gradually depending on the length of stock period of samples. This result may be comparative to another observation that the amount and density distribution of precipitate from extract varied with the lapse of stock time, based on accelerated sedimentation test. The number of SDS-PAGE protein bands was observed to be at least seven when determined with the extract of fresh ginseng. However, it tended to reduce finally to be one band when the extract was kept at a rather high temperature for a long time.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.783-790
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• 2016

Objectives: The purpose of this study is to evaluate the non-enzymatic antioxidants stabilities in dentifrices by ascorbic acid and tocopherol according to the chemical condition. Methods: For the analysis of two antioxidants, HPLC UV detector system was used. HPLC was performed using sodium sulfate, acetonitrile(ACN), methanol(MeOH) and measuring absorbance at 240-295 nm. To confirm general pH reaction of two compounds, buffer solution was prepared for the analysis. The dentifrice was titrated by pH so as to examine the change of elapsed time in dentifrice. Linearity of calibration curve of two antioxidants was measured. Results: Each compound showed good linearity at optimized wavelength as well as showing good precision. General pH reaction of two antioxidants was examined. Ascorbic acid showed the highest residue(63.23%) at pH 10 and the lowest residue(2.77%) at pH 4. Tocopherol showed the highest residue(55.70%) at pH 7 and the lowest residue(3.31%) at pH 4. As a result of changing elapsed time of antioxidants in dentifrice by pH, components were remained stably at low temperature($39.2^{\circ}F$) and pH 7. Conclusions: It is necessary to keep dentifrice including ascorbic acid and tocopherol, and non-enzymatic antioxidants at pH 7 and low temperature for improving chemical stability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.6
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• pp.284-289
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• 2003

The electric furnace, inside which the desired temperature is kept by the generated heat, is known to be a difficult system to control and model exactly because system parameters and response delayed time are varied as the temperature and positions are changed. In this study, the GPCEW (generalized predictive control with exponential weight), which always guarantees the stability of the closed loop system and can be effectively applied to the internally unstable system, was introduced to the ceramic drying electric furnace and was verified by showing its temperature tracking performance experimentally.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.101-108
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• 2011

On cold start operation of an SI engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of spark timing. Combustion stability is also considered at the same time. Exhaust gas temperature and pressure of combustion chamber are measured to investigate the effects of spark timings on cold start and idle performance. Experiments showed that retarded spark timing promotes the combustion at the end of expansion stroke and increases exhaust gas temperature during cold start.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.599-605
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• 2012

It is important to decide traffic opening time for construction plan of epoxy asphalt pavement. For this purpose, strength prediction model of epoxy asphalt concrete is required. In this study, Marshall stability was measured according to temperature and time for making strength properties equation. Strength prediction model was developed using chemical kinetics considering temperature variation. The traffic opening time of epoxy asphalt pavement on bridge deck has been predicted using the developed model. The prediction and actual traffic opening times were different by 17-days, because weathers of year 2009-2011 used in prediction model were different from weather of year 2012. When the prediction model used the actually measured temperatures of pavement, the difference between real opening time and prediction opening time was two days. The correlation analysis result between measured strength and prediction strength revealed that the $R^2$ using accurate temperature of pavement was 0.95. An improved precise prediction result is to be obtained if the prediction model uses accurate temperature data of pavement.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.289-295
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• 2016

Curcumin is a flavonoid found in the rhizome of the turmeric plant (Curcuma longa L.) and has recently attracted interest because it has numerous biological functions and therapeutic properties. In the present study, we attempted to incorporate curcumin into medium-chain triglyceride (MCT) nanoemulsions (0.15 wt% curcumin, 10 wt% MCT oil, and 10 wt% emulsifiers) with various emulsifiers [polyoxyethylene (20) sorbitan monolaurate (Tween-20), sorbitan monooleate (SM), and soy lecithin (SL)]. The physicochemical properties of the nanoemulsions including the Ostwald ripening stability were investigated. The initial droplet size was found to be 89.08 nm for the nanoemulsion with 10 wt% Tween-20 (control), and when Tween-20 was partially replaced with SM and SL, the size decreased: 73.43 nm with 4 wt% SM+6 wt% Tween-20 and 67.68 nm with 4 wt% SL+6 wt% Tween-20 (prepared at 15,000 psi). When the nanoemulsions were stored for 28 days at room temperature, the droplet size increased as the storage time increased. The largest increase was observed for the control nanoemulsion, followed by the 4 wt% SL+6 wt% Tween-20 and 4 wt% SM+6 wt% Tween-20 systems. The Turbiscan dispersion stability results strongly supported the relationship between droplet size and storage time. The time-dependent increase in droplet size was attributed to the Ostwald ripening phenomenon. Thus, the Ostwald ripening stability of curcumin-loaded MCT nanoemulsions with Tween-20 was considerably improved by partially replacing the Tween-20 with SM or SL. In addition, curcumin may have acted as an Ostwald ripening inhibitor.

• Analytical Science and Technology
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• v.36 no.1
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• pp.32-43
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• 2023

This study reports for the first time about a stability indicating RP-HPLC method for qualitative and quantitative determination of acalabrutinib in bulk and dosage form and in presence its impurities 1, 2 and 3. The chromatographic separation was carried on Zorbax XDB-C18 (250×4.6 mm; 5 µ id) as stationary phase, Phosphate buffer pH 6.4 and methanol 80:20 (v/v) as mobile phase at a flow rate of 1.0 mL/min, UV detection was carried at wavelength of 238 nm and the analysis was completed with a run time of 15 min. In these conditions the retention time of acalabrutinib and its impurities 1, 2 and 3 was observed to be 3.50, 4.83, 8.40 and 9.93 min respectively. The method was validated for system suitability, range of analysis, precision, specificity, stability and robustness. Spiked recovery at 50 %, 100 % and 150 % was carried for both standard and impurities and the acceptable % recovery of 98-102 was observed for acalabrutinib and both impurities studied and the % RSD in each spiked level was found to be less than 2. Stability tests were done through exposure of the analyte solution to five different stress conditions i.e expose to 1N hydrochloric acid, 1 N sodium hydroxide, 3 % peroxide, 80 ℃ temperature and UV radiation at 254 nm. In all the degradation condition, standard drug acalabrutinib was detected along with both the impurities studied and the degradation products were successfully separated. In the formulation analysis there is no other chromatographic detection of other impurities and formulation excipients. Hence the developed method was found to be suitable for the quantification of acalabrutinib and can separate and analyse impurities 1 and 2.