• Korean Journal of Materials Research
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• v.10 no.1
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• pp.49-54
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• 2000

The new green $Al_3GdB_4O_{12}:Tb^{3+} and red Al_3GdB_4O_{12}:Eu_{3+}$ phosphors were synthesized and then characterized their optical properties for PDP application. And also the photoluminescence properties of these phosphors were compared with the commercial green $Zn_2SiO_4:Mn^{2+} and (Y,Gd)BO_3: Eu^{3+}$ red PDP phosphors. The phosphors were synthesized by solid state reaction at 115$0^{\circ}C$ for 4hr. It was found that the emitting brightness of $Al_3GdB_4O_{12}:Tb^{3+}$(15mol%) green phosphor under 147nm excitation was higher than that of commercial $Zn_2SiO_4: Mn^{2+}$ green PDP phosphor. However, the color coordinate of this new green phosphor was inferior to the commercial one. On the other hand, the emitting intensity of $Al_3GdB_4O_{12}:Eu^{3+}$(15mol%) red phosphor was smaller than the $commercial(Y,Gd)BO_3: Eu^{3+}$ red one, but the CIE coordinate was slightly improved. The excitation spectrum showed that $Al_3GdB_4O_{12}$ phosphors had a strong excitation band at $\lambda=160nm$ associated with the host absorption. And the photoluminance excitation (PLE) intensity in VUV range for $Al_3GdB_4O_{12}:Tb^{3+}$ green phosphor was higher than that of $Zn_2SiO_4: Mn^{2+}$, but the PLE intensity of $Al_3GdB_4O_{12}:Eu^{3+}$ red phosphor was smaller than $(Y,Gd)BO_3: Eu^{3+}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.31-31
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• 2010

The growth of the high-quality GaN epilayers is of significant technological importance because of their commercializedoptoelectronic applications as high-brightness light-emitting diodes (LEDs) and laser diodes (LDs) in the visible and ultraviolet spectral range. The GaN-based heterostructural epilayers have the polar c-axis of the hexagonal structure perpendicular to the interfaces of the active layers. The Ga and N atoms in the c-GaN are alternatively stacked along the polar [0001] crystallographic direction, which leads to spontaneous polarization. In addition, in the InGaN/GaN MQWs, the stress applied along the same axis contributes topiezoelectric polarization, and thus the total polarization is determined as the sum of spontaneous and piezoelectric polarizations. The total polarization in the c-GaN heterolayers, which can generate internal fields and spatial separation of the electron and hole wave functions and consequently a decrease of efficiency and peak shift. One of the possible solutions to eliminate these undesirable effects is to grow GaN-based epilayers in nonpolar orientations. The polarization effects in the GaN are eliminated by growing the films along the nonpolar [$11\bar{2}0$] ($\alpha$-GaN) or [$1\bar{1}00$] (m-GaN) orientation. Although the use of the nonpolar epilayers in wurtzite structure clearly removes the polarization matters, however, it induces another problem related to the formation of a high density of planar defects. The large lattice mismatch between sapphiresubstrates and GaN layers leads to a high density of defects (dislocations and stacking faults). The dominant defects observed in the GaN epilayers with wurtzite structure are one-dimensional (1D) dislocations and two-dimensional (2D) stacking faults. In particular, the 1D threading dislocations in the c-GaN are generated from the film/substrate interface due to their large lattice and thermal coefficient mismatch. However, because the c-GaN epilayers were grown along the normal direction to the basal slip planes, the generation of basal stacking faults (BSFs) is localized on the c-plane and the generated BSFs did not propagate into the surface during the growth. Thus, the primary defects in the c-GaN epilayers are 1D threading dislocations. Occasionally, the particular planar defects such as prismatic stacking faults (PSFs) and inversion domain boundaries are observed. However, since the basal slip planes in the $\alpha$-GaN are parallel to the growth direction unlike c-GaN, the BSFs with lower formation energy can be easily formed along the growth direction, where the BSFs propagate straightly into the surface. Consequently, the lattice mismatch between film and substrate in $\alpha$-GaN epilayers is mainly relaxed through the formation of BSFs. These 2D planar defects are placed along only one direction in the cross-sectional view. Thus, the nonpolar $\alpha$-GaN films have different atomic arrangements along the two orthogonal directions ($[0001]_{GaN}$ and $[\bar{1}100]_{GaN}$ axes) on the $\alpha$-plane, which are expected to induce anisotropic biaxial strain. In this study, the anisotropic strain relaxation behaviors in the nonpolar $\alpha$-GaN epilayers grown on ($1\bar{1}02$) r-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVO) were investigated, and the formation mechanism of the abnormal zigzag shape PSFs was discussed using high-resolution transmission electron microscope (HRTEM).

• Journal of the Korean earth science society
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• v.21 no.2
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• pp.137-158
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• 2000

The correlation and Empirical Orthogonal Function (EOF) analyses over the globe have been applied to intercompare lower-stratospheric (${\sim}$70hPa) temperature obtained from satellite data and two model reanalyses. The data is the19 years (1980-98) Microwave Sounding Unit (MSU) channel 4 (Ch4) brightness temperature, and the reanalyses are GCM (NCEP, 1980-97; GEOS, 1981-94) outputs. In MSU monthly climatological anomaly, the temperature substantially decreases by ${\sim}$21k in winter over southern polar regions, and its annual cycle over tropics is weak. In October the temperature and total ozone over the area south of Australia remarkably increase together. High correlations (r${\ge}$0.95) between MSU and reanalyses occur in most global areas, but they are lower (r${\sim}$O.75) over the 20-3ON latitudes, northern America and southern Andes mountains. The first mode of MSU and reanalyses for monthly-mean Ch4 temperature shows annual cycle, and the lower-stratospheric warming due to volcanic eruptions. The analyses near the Korean peninsula show that lower-stratospheric temperature, out of phase with that for troposphere, increases in winter and decreases in summer. In the first mode for anomaly over the tropical Pacific, MSU and reanalyses indicate lower-stratospheric warming due to volcanic eruptions. In the second mode MSU and GEOS present Quasi-Biennial Oscillation (QBO) while NCEP, El Ni${\tilde{n}}$o. Volcanic eruption and QBO have more impact on lower-stratospheric thermal state than El Ni${\tilde{n}}$o. The EOF over the tropical Atlantic is similar to that over the Pacific, except a negligible effect of El Ni${\tilde{n}}$o. This study suggests that intercomparison of satellite data with model reanalyses may estimate relative accuracy of both data.

• Journal of The Korean Association For Science Education
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• v.19 no.3
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• pp.428-440
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• 1999

The colorful overhead projector films, named as Bio-cosmos II, including photographs, pictures, concept maps, and diagrams, were developed and manufactured as audio-visual teaching aids and teaching resources for students' biology learning in high school, and the CD-ROM and web sites for their application to the school were also constructed. The content of the films was organized based upon the analysis of seven different biology textbooks approved by the Ministry of Education. The films were designated based on various instructional strategies and manufactured using multimedia with various educational softwares. The CD-ROM was composed of the scenes as logo, initial main, chapters list, contents, and quit. Initial main scene indicated various chapters according to the texts of biology areas in General Science, Biology I, and II. Each chapters linked with the scenes for detailed concept maps, the downstream real subjects, and contents. The subject screens were composed of various types of summarized diagrams including lesson contents, figures, pictures, photographs, and their explanation, experimental procedures and results, tables for summarized contents, and additional animation with video captures, explanations, glossary, etc. Most files were manufactured in software Adobe Photoshop by scanning the pictures, figures and photographs, and then the explanation, modification, storing with PICT or PSD files, and transformation with JPG files, were processed in the aspect of high quality in terms of instructional strategies and graphic skills on gracefulness, clearness, colorfulness, brightness, and distinctness. A 14 films for biology areas in General Science, 80 for Biology I, and 142 for Biology II were manufactured and loaded to the CD-ROM and web site, and the files had been attempted to opened with an internet home-page of http://gic.kyungpook.ac.kr/biocosmos.

• Culinary science and hospitality research
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• v.22 no.8
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• pp.226-234
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• 2016

In this study, the possibility of developing new type of yanggaeng has been reviewed by evaluating physio-chemical and sensual characteristics of new yanggaeng products using 5~20% of powder of plantain that is a hardy plant resource from most of hillside in Korea. The moisture contents of plantain powder was 1.9%, DPPH radical scavenging ability was 15.67 mg/mL, and total polyphenol contents was 7.00mg/g. By increasing the adding rate of plantain powder the moisture contents and pH of yanggaeng were decreased. From chromatography, by increasing the adding rate of plantain powder the brightness, L-value was decreased along with redness, a-value, yellowness, and b-value. The a-value of sample group adding 5% of plantain powder was the highest and that of sample group adding 20% was the lowest (p<0.001). From texture measurement shown that the hardness of sample group adding 5% of plantain powder was the highest by 3,937.04 and that of sample group adding 20% of plantain powder was the lowest by 2,153.59. The springiness of sample group adding 5% of plantain powder was the highest by 6.79% and that of sample group adding 20% of plantain powder was the lowest by 4.76%. The cohesiveness of sample group adding 20% of plantain powder was the lowest by 177.35 and it was significant (p<0.001). The result of sensory test showed that sample group adding 10% of plantain powder achieved the highest appraisal from most factors, such as color, scent. sweetness, chewiness, moist level, softness level and total preference. As shown from the above results, the sensory preference of yanggaeng can be improved by adding proper volume of plantain powder while making it, so it is understood that the addition of plantain powder in making yanggaeng would give better possibility in commercialization. By considering sensory preference factor the 10% addition rate of plantain powder while making yanggaeng would be the most proper recipe.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.221-226
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• 2012

For the investigation of a possibility as a useful functional material, 6 cultivars (Takinosawa Gold, Kawanakawase Hakuto, Madoka, Yumefuji, Nagasawa Hakuho, Hong Bak) of Prunus persica L. Batsch were studied at unripe stage to determine the physicochemical properties and chemical compositions. The cultivars were picked in late May, and all samples were analyzed for external properties, physicochemical properties, pH, Brix value, Hunter's color value, hardness, vitamin C, and reducing sugar. The size of the fruit from all six cultivars was compared, and it was determined that cultivars, fruit from Madoka was the largest, while that from Yumefuji was the smallest. Comparing fresh weight, the fruit from Yumefuji was lowest in moisture contents (89.13~89.96%), and that from Nagasawa Hakuho had significantly higher crude protein (1.02~1.62%). The contents of crude lipids (0.18~0.23%) and carbohydrates (8.00~9.35%) were not significantly different between cultivars and Madoka included higher crude ash contents (0.32~0.69%) than other cultivars. The pH of 6 cultivars from unripe peaches were significantly higher from Kawanakawase Hakuto, and the Brix value was also highest from Kawanakawase Hakuto, followed by Yumefuji, Madoka, Nagasawa Hakuho, Takinosawa Gold, and Hong Bak. In chromaticity, the L value, the indicator of brightness, was significantly higher in fruit from Nagasawa Hakuho. The a value, the indicator of redness, was the highest with Hong Bak and overall lower than -5. The b value, the indicator of yellowness, was the highest in fruit from Madoka and ranged from 16.51 to 18.33. In physical characteristics, the hardness of the unripe peaches was the highest in fruit from Hong Bak, and overall, white peaches have a higher hardness value than yellow peaches. The vitamin C content of the fruit didn't show any significant differences between cultivars, and the reducing sugar showed a higher percent than 6.34% in fruit from all cultivars. These results suggest that unripe peaches were commensurate with the development of natural pigment and as a functional foods.

• The Korean Journal of Food And Nutrition
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• v.29 no.1
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• pp.65-72
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• 2016

Black tomato (Lycopersicum esculentum) is known to have more ${\beta}-carotene$, lycopene, and vitamin C than general red-colored tomatoes. In this study, we evaluated the quality properties, antioxidant activities and sensory characteristics of black tomato cookies. Cookies were prepared by replacing 0, 1, 3, 5, and 7% of flour with black tomato powder. Density of black tomato cookies tended to be decreased between control (1.20) and 3% added groups (1.12). pH value was decreased from control (6.66) to 7% added group (5.16). Spread factor and loss rate were increased with increasing amounts of black tomato powder. Hardness was gradually increased from $107.77g/cm^2$ in control to $170.50g/cm^2$ in 7% added group. Color measurement indicated that L-value (brightness) was highest in control (70.46) and lowest in 7% added group (45.23); whereas, a-value (redness) increased while b-value (yellowness) tended to decrease with increasing amounts of black tomato powder. Total polyphenol contents and DPPH radical scavenging activities were directly proportional to the amount of black tomato powder. Consumer preference scores in color and flavor of black tomato powder added group were higher than those of control. Characteristic strength test was not significantly different among the groups. Overall, the results indicated that adding 5% black tomato powder is desirable for making black tomato cookies.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.203-209
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• 1999

The effect of several hydrocolloids on the rheological behavior of wheat flour was investigated. The influence of the selected hydrocolloids (alginate, carrageenan, CMC, guar, locustbean and xanthan) on wheat flour was tested by using two different techniques; amylograph and texture analyzer. In order to have a general overview of their effects hydrocolloids were chosen from different sources implying a broad diversity of chemical structures. The hydrocolloid addition decreased the brightness(L) but increased yellowness(b). The interaction between hydrocolloid and flour produces a slight modification of the amylogram parameters, being the most clearly affected parameter breakdown, which is increased by carrageenan, guar and xanthan. Hardness and cutting force were augmented by hydrocolloid addition, while springeness was decreased except guar and locustbean. In summary, when looking for the improvement of the noodle texture, guar, locustbean are the best candidate additives due to their effects on pasting and texture properties. These hydrocolloids increase the hardness, cutting force, gumness, chew-ness, so were thought to increase the eating quality. So, each tested hydrocolloid affected in a different way the rheological properties of wheat flour, the results obtained are important for the appropriate use of these hydrocolloid as ingredients in the noodle making process.

• Korean journal of food and cookery science
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• v.24 no.6
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• pp.742-747
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• 2008

This study was performed to evaluate the quality characteristics of the hamburger patty to which Chungkukjang powder (CJP; 0, 2, 4, and 6%) had been added. The contents of moisture, crude protein and crude ash in the control group(0%) were significantly(p<0.01) lower than that of the CJP patties, but crude lipid content in the control group was significantly (p<0.01) higher than that of the treated group. The values of L(brightness) and b(yellowness) of the control group were lower than that of the CJP patties, but a-value(redness) of the control group exhibited the highest score. The texture of the control group was significantly(p<0.05) harder than that of the CJP patties. Among the mean scores of sensory characteristics of samples, the patty with 2% CJP powder showed the highest sensory score, and also, had significantly(p<0.05) higher chewiness than the control group. In preference, the control group showed a higher score than the treated group, but this difference was not statistically significant. The patty with 2% CJP had significantly (p<0.01) higher consumer sensory score in texture than that of markets. The results showed that the CJP patties could contribute toward complementing the nutrients of hamburgers on sale. Furthermore, the results of this study can contribute toward improving the nutritional and functional well-being of products.

• Journal of Gifted/Talented Education
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• v.11 no.3
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• pp.131-153
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• 2001

The importance of identifying gifted children during early childhood is becoming recognized. Nonetheless, most researchers preferred to study the primary and secondary levels where children are already and more clearly demonstrating what talents they have, and where more reliable predictions of gifted may be made. Comparatively lisle work has been done in this area. When we identify giftedness during early childhood, we have to consider the potential of the young children rather than on actual achievement. Giftedness during early childhood is still developing and less stable than that of older children and this prevents us from making firm and accurate predictions based on children's actual achievement. Dynamic assessment, based on Vygotsky's concept of the zone of proximal development(ZPD), suggests a new idea in the way the gifted young children are identified. In light of dynamic assessment, for identifying the potential giftedness of young children. we need to involve measuring both unassisted and assisted performance. Dynamic assessment usually consists of a test-intervene-retest format that focuses attention on the improvement in child performance when an adult provides mediated assistance on how to master the testing task. The advantages of the dynamic assessment are as follows: First, the dynamic assessment approach can provide a useful means for assessing young gifted child who have not demonstrated high ability on traditional identification method. Second, the dynamic assessment approach can assess the learning process of young children. Third, the dynamic assessment can lead an individualized education by the early identification of young gifted children. Fourth, the dynamic assessment can be a more accurate predictor of potential by linking diagnosis and instruction. Thus, it can make us provide an educational treatment effectively for young gifted children.