• Applied Science and Convergence Technology
• /
• v.26 no.2
• /
• pp.21-25
• /
• 2017

The shape of the reflection spectrum is complex and appears to overlap with several signals, because the surface state is uneven due to the natural oxide film, so that the spectrum becomes a complicated signal shape divided into regions 1 and 2 due to diffuse reflection. On the other hand, it is seen that the reflection spectrum after PEO surface treatment is overlapped with several signals. In addition, the reflectance of the energy band varies from 1.32 to 1.46 eV. Usually, the MgO-type oxide film was observed at an energy band of ~4.2 eV. The thickness of the oxide film was increased as the DC voltage was increased by the thin film thickness meter (QuaNix; 7500M) after Plasma Electrolytic Oxidation (; PEO) surface treatment. This is because the higher the DC voltage, the easier the binding of the $OH^-$ ions in the solution solution and the $Mg^+$ ions of the magnesium alloy. An important part of the bonding of ordinary ions is the energy source (plasma) which can promote bonding. However, when a certain threshold voltage or more is applied, the material is adversely affected. The oxide film of the surface may be destroyed without increasing the thickness of the oxide film, that is, whitening of the material may occur.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.7
• /
• pp.999-1004
• /
• 2010

This study was carried out to investigate the quality characteristics of ginseng Jung Kwa obtained by treatments with different sugars. Ginseng Jung Kwa was made with four different sugars (sucrose, glucose, honey and fructose). Chemical characteristic was measured by ginsenosides content and rheological characteristics were measured by rheometer and color meter. Total ginsenoside and Rf contents on Ginseng Jung Kwa by sucrose were highest at 10.0, and 7.82 mg/g, respectively. On ginseng Jung Kwa by fructose, total ginsenoside content was the lowest, and hardness and adhesiveness were the highest, and by honey, stiffness, cohesiveness, gumminess, chewiness, and springiness were the highest, and fracture force did not appear as a significant difference by treatment of different sugars. Coefficient of variance on ginseng Jung Kwa by honey was the highest. On ginseng Jung Kwa by sucrose, color (lightness, redness and yellowness) all were the highest. Browning on Jung Kwa by fructose was the greatest. Sensory evaluation preference analysis (color, taste, texture, flavor and overall acceptability) on ginseng Jung Kwa were determined by 50 panelists (30~50's age) using 5-point scale. On ginseng Jung Kwa by honey, texture and overall acceptability were the best. Ginseng Jung Kwa by fructose was very sticking and adhering, so preference by sensory evaluation was inferior to others.

• Korean Journal of Food Science and Technology
• /
• v.31 no.1
• /
• pp.45-53
• /
• 1999

Physicochemical and sensory characteristics of cooked rice during warm-keeping with different temperature $(70,\;75,\;80^{\circ}C)$ and period (0, 6, 12, 24, 48 hr) were investigated. As the storage temperature increased, sweet flavor, glossiness, moistness, taste and moisture content decreased but off-flavor, color and sensory and texturometric hardness increased. This trend was significant with storage period. As the storage time and temperature increased, yellowness(b) measured by Hunter color difference meter increased while lightness(L) and whiteness decreased. Degree of retrogradation of cooked rice during storage increased, particularly did in cooked rice stored at $80^{\circ}C$. Cooked rice stored at 70 and $75^{\circ}C$, 6 hr had the least changes in flavor and appearance but more changes in them longer storage time. Cooked rice stored at $80^{\circ}C$ had rapid changes in flavor, appearance and texture at initial state of storage. These results showed that the changes in moisture content of cooked rice stored at various conditions had the most important effect upon sensory characteristics of cooked rice.

• Journal of the Korean Ceramic Society
• /
• v.56 no.2
• /
• pp.178-183
• /
• 2019

A process of fabricating the foamed glass that has closed pores with 8 ~ 580 ㎛ sizes without a blowing agent by sintering 10 ㎛ boron-free glass powder composed of CaO, MgO, SO₃, Al₂O₃-83 wt% SiO₂ at a molding pressure of 0 ~ 120 MPa and a sintering temperature of 750 ~ 1000℃ was investigated. To analyze the glass transition temperature of glass powder, thermogravimetric analysis-differential thermal analysis (TGA-DTA) method were used. The microstructure and pore size of foamed glass were examined using the optical microscopy and field emission scanning electron microscopy (FE-SEM). For the thermal diffusivity and color of the fabricated samples, a heat flow meter and ultraviolet-visible-near-infrared (UV-VIS-NIR)-colormetry were used, respectively. In the TGA-DTA result, the glass transition temperature of glass powder was confirmed to be 626℃. In the microstructure result, closed pores of 7 ~ 20 ㎛ were formed at 750 ~ 900℃, and they were not affected by the molding pressure and sintering temperature. However, at 1,000℃, when there was 0 MPa molding pressure, closed pores of 580 ㎛ were confirmed, and the pore size decreased as the molding pressure increased. Moreover, at a molding pressure of 30 MPa or higher, closed pores of approximately 400 ㎛ were formed. The porosity showed an increasing trend of smaller molding pressure and larger sintering temperature, and it was controllable in the range of 5.69 ~ 68.45%. In the thermal diffusivity result, there was no change according to the molding pressure, and, by increasing the sintering temperature, up to 0.115 W/m·K could be obtained. The Lab color index (CIE-Lab) results all showed a similar translucent white color regardless of molding pressure and sintering temperature. Therefore, based on the foamed glass without boron and blowing agent, it was confirmed that white foamed glass, which has closed pores of 8 ~ 580 ㎛ and a thermal diffusivity characteristic of 0.115 W/m·K, can be fabricated by changing the molding pressure and sintering temperature.

• Korean journal of food and cookery science
• /
• v.17 no.3
• /
• pp.237-245
• /
• 2001

The purpose of this study was to develop a standardized recipe of Hwajeun(glutinous rice pancake with flower) by evaluating various methods appeared in the literature. For this purpose, the effects of the volume and temperature of water used to make dough on the sensory and rheological characteristics of Hwajeun were investigated. This experiment consisted of sensory evaluation in acceptance and intensity(appearance, color, moistness, softness, chewiness, adhesiveness, taste and overall preference), objective evaluation by using texture analyser, color difference meter and measurement of water content and oil absorption ratio. The loss ratio of moisture contents between dough and cooked Hwajeun were 2.4 ~2.8%, and the oil absorption ratio of Hwajeun made by 2$0^{\circ}C$water for kneading increased in proportion to the increment of water added(p＜0.01). In terms of color, b value of Hwajeun made by 104$^{\circ}C$ salted water for kneading showed higher value compared to the others. In the two bite compression test, adhesiveness, springiness, gumminess and chewiness of Hwajeun made by 2$0^{\circ}C$ water(36%) for kneading showed significantly(p＜0.05) high value among the samples. As a result of sensory evaluation, Hwajeun made with 27% of 104$^{\circ}C$ salted water for kneading was most preferred in softness, chewiness, taste and overall preference

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.48 no.4
• /
• pp.313-319
• /
• 2022

In this study, the stability of cream containing 1% of cannabidiol (CBD) with more than 99% extracted from domestic Cannabis sativa was evaluated. The pH, hardness, content, and chromaticity were measured at intervals of 2 weeks under storage conditions for each temperature for 12 weeks (4 ℃, 25 ℃, 37 ℃, and 45 ℃). The pH of the experimental group containing 1% of CBD tended to decrease more than that of the control group. As a result of measuring the change in the content of CBD in the cream under each temperature for 12 weeks using HPLC, the difference in the amount of decrement according to temperature was confirmed. It was confirmed that as a result of measuring the chromaticity using color difference meter, the yellowness of the cream containing CBD increased according to the increase by the storage period and temperature compared to the control group. From the above results, it was confirmed that the content decrease and color change according to the temperature of the pH 5 ~ 6 cream formulation containing CBD. When CBD is applied to medicine and cosmetic formulations in the future, it is considered that research and development should be conducted in consideration of the change in the quantity and physicochemical quality of CBD under the temperature.

• The Journal of Korean Academy of Prosthodontics
• /
• v.47 no.1
• /
• pp.1-11
• /
• 2009

Statement of problem: There are two methods of color choice for the esthetic restoration. One is visual shade matching which draws a comparison between shade guide and teeth in dentist's own eye and the other is using a digital shade analysis system recently introduced. Although the visual shade matching has a lot of problems, decision of color by this visual shade matching and the ways of expression for the decided color are still applicable to clinical dentistry. Purpose: This study is designed to investigate shade guides used in the dental clinics and laboratories have the same value using ShadeEye-$NCC^{(R)}$ dental chroma meter (Shofu Inc., Kyoto, Japan) using shade guide are evaluated. Material and methods: At the first experiment, eight Vita Lumin Vacuum shade guides (Vident Inc., California, USA) were collected from the dental clinics. A1 and B1 shade tabs are chosen and the colors are analyzed five times each in both tooth and porcelain modes by digital shade analysis system, ShadeEye-$NCC^{(R)}$. In the second experiment, twelve Vita shade guides using practically in the dental clinics and laboratories were collected and also A1 and B1 shade tabs are chosen and the colors of A1 and B1 are analyzed one time each in both tooth and porcelain modes by ShadeEye-$NCC^{(R)}$. Results and conclusion: There were significant differences among eight shade guides in terms of shade (chroma), value and hue in both of A1 and B1 (P<.05). Shade guides using in present both dental clinics and laboratories did not show significant differences, except A1 in the porcelain mode, it showed significant differences (P<.05) in the shade even though the shade tab has the same name.

• Ocean Science Journal
• /
• v.40 no.1
• /
• pp.25-44
• /
• 2005

Long-term, continuous, and real-time ocean monitoring has been undertaken in order to evaluate various oceanographic phenomena and processes in the East/Japan Sea. Recent technical advances combined with our concerted efforts have allowed us to establish a real-time monitoring system and to accumulate considerable knowledge on what has been taking place in water properties, current systems, and circulation in the East Sea. We have obtained information on volume transport across the Korea Strait through cable voltage measurements and continuous temperature and salinity profile data from ARGO floats placed throughout entire East Sea since 1997. These ARGO float data have been utilized to estimate deep current, inertial kinetic energy, and changes in water mass, especially in the northern East Sea. We have also developed the East Sea Real-time Ocean Buoy (ESROB) in coastal regions and made continual improvements till it has evolved into the most up-to-date and effective monitoring system as a result of remarkable technical progress in data communication systems. Atmospheric and oceanic measurements by ESROB have contributed to the recognition of coastal wind variability, current fluctuations, and internal waves near and off the eastern coast of Korea. Long-tenn current meter moorings have been in operation since 1996 between Ulleungdo and Dokdo to monitor the interbasin deep water exchanges between the Japanese and Ulleung Basins. In addition, remotely sensed satellite data could facilitate the investigation of atmospheric and oceanic surface conditions such as sea surface temperature (SST), sea surface height, near-surface winds, oceanic color, surface roughness, and so on. These satellite data revealed surface frontal structures with a fairly good spatial resolution, seasonal cycle of SST, atmospheric wind forcing, geostrophic current anomalies, and biogeochemical processes associated with physical forcing and processes. Since the East Sea has been recognized as a natural laboratory for global oceanic changes and a clue to abrupt climate change, we aim at constructing a 4-D continuous real-time monitoring system, over a decade at least, using the most advanced techniques to understand a variety of oceanic processes in the East Sea.

• Restorative Dentistry and Endodontics
• /
• v.31 no.4
• /
• pp.269-281
• /
• 2006

This study evaluated the effectiveness and safety of an experimental bleaching strip (Medison dental whitening strip. Samsung medical Co., Anyang, Korea) containing 2.9% hydrogen peroxide. Twenty-three volunteers used the bleaching strips for one and a half hour daily for 2 weeks. As control group. the same strips in which hydrogen peroxide was not included were used by 24 volunteers with the same protocol. The shade change (${\Delta}E^{*}$, color difference) of twelve anterior teeth was measured using Shade Vision (X-Rite Inc., S.W. Grandville, MI, USA). Chroma Meter (Minolta Co., Ltd. Osaka. Japan) and Vitapan classical shade guide (Vita Zahnfabrik, Germany). The shade change of overall teeth in the experimental group was significantly greater than that in the control group (p < 0.05) and was easily perceivable. The change resulted from the increase of lightness (CIE $L^{*}$ value) and the decrease of redness (CIE $a^{*}$ value) and yellowness (CIE $b^{*}$ value). The shade change of individual tooth was greatest in canine. and smallest in central incisor. The safety of the bleaching strip was also confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.8
• /
• pp.627-633
• /
• 2019

Rapid and accurate identification of marine microalgae causing harmful algal blooms (HABs) is a crucial tool for predicting and managing HABs. We previously developed a nuclease protection assay sandwich hybridization (NPA-SH) method for the in situ detection of blooming microalgae Cochlodinium polykrikoides. In this study, we improved the applicability of the NPA-SH method for the detection of C. polykrikoides by simplifying the reaction step. For this purpose, invertase (INV) was conjugated to the signal probe instead of using fluorescence, and sucrose was used as a reactant to induce a color reaction. The INV-signal probe conjugation was confirmed by SDS-PAGE and epifluoromicroscopy. The treatment time and appropriate amounts of the probe and sucrose that optimized the reaction were determined. As a result, the developed INV-SH reduced the treatment time in the field compared with NPA-SH, and also enabled the use of a relatively small volume and low-priced personal glucose meter, as well as an absorbance meter. INV-SH is the first C. polykrikoides species identification technology to which INV has been applied and could be an improved field technique.