• The Korean Journal of Zoology
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• v.29 no.3
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• pp.215-233
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• 1986

The effect of tryptophan on brain formation at the early stage of chick embryo has been investigated morphologically using electron microscope. The electron micrographs of cerebral cortex cells of $5\\sim10$ day old chick embryo, which received 1.0mg of tryptophan showed that the irregularity, evagination and disruption of nuclear membrane and nuclear chromatin condensation, nucleolar chromatin margination and segragation. Hypertrophy of stalks, vesicles, and vacuoles can be seen and dilation and vesiculation of rough endoplamic reticulum and polysome disaggregation occured. Protein and RNA levels and the activity of several enzymes such as lactate dehydrogenase, succinate dehydrogenase, malate dehydrogenase and glucose 6-phosphate dehydrogenase of tryptophan administered group were significantly lower than those of control group suggesting that the tryptophan administration depressed protein biosynthesis resulting in the decrease of enzyme activity. It was found that serotonin content of egg yolk which has been incubated for 10 days were as much as three times that of control egg yolk. It is not clear whether the increase of serotonin content might inhibit intracellular yolk granule degradation which might result in malformation of chick embryo, but it is likely that tryptophan administration might depress protein biosynthesis, consequently, the enzyme biosynthesis would be impaired. This might give rise to improper development of chick embryo.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.140-149
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• 2014

The purpose of this study was to investigate the influence of etching surface treatment and aging treatment of zirconia on the shear bond strength between zirconia core and veneered ceramic. Four groups of zirconia-ceramic specimens were prepared; 1) NEZ group (no etching zirconia), 2) EZ group (etching zirconia), 3) ANEZ group (aging and no etching zirconia), 4) AEZ group (aging and etching zirconia). The shear bond strength between zirconia and porcelain was measured using Instron Universal Testing Machine. Surface texture with crystalline structure of zirconia surface was examined by the field emission scanning electron microscopy (FE-SEM) with ingredient analysis. The fractured surfaces of specimens were examined to determine the failure pattern by a digital microscope. The mean${\pm}$standard deviation of shear bond strengths were $23.47{\pm}3.47$ Mpa in NEZ, $28.30{\pm}4.34$ Mpa in EZ, $21.85{\pm}4.65$ Mpa in ANEZ, $24.65{\pm}3.65$ Mpa in AEZ group, respectively, and were significantly different (p<0.05). The average shear bond strength was largest in EZ group, followed by AEZ, NEZ, and ANEZ groups. Most specimens in NEZ group showed adhesive failure and most specimens in EZ, AEZ, and ANEZ group showed mixed failure. Surface of etching treatment group (EZ and AEZ) showed complex micro-structure and irregular surface texture which may facilitate mechanical interlocking, while untreated zirconia surface presented simpler micro-structure. In conclusion, an etching treatment improved bonding strength between zirconia and porcelain by forming mechanical interlocking.

• Resources Recycling
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• v.27 no.2
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• pp.24-31
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• 2018

In this study, waste ITO target is dissolved into hydrochloric acid to generate a complex indium-tin chloride solution. Nano sized ITO powder with an average particle size below 30 nm are generated from these raw material solutions by spray pyrolysis process. Also, in this study, thermodynamic equations for the formation of indium-tin oxide (ITO) are established. As the reaction temperature increased from $800^{\circ}C$ to $900^{\circ}C$, the proportion and size of the spherical droplet shape in which nano sized particles aggregated gradually decreased, and the surface structure gradually became densified. When the reaction temperature was $800^{\circ}C$, the average particle size of the generated powder was about 20 nm, and no significant sintering was observed. At a reaction temperature of $900^{\circ}C$, the split of the droplet was more severe than at $800^{\circ}C$, and the rate of maintenance of the initial atomized droplet shape decreased sharply. The average particle size of the powder formed was about 25 nm. The ITO particles were composed of single solid crystals, regardless of reaction temperature. XRD analysis showed that only the ITO phase was formed. Remarkably, the specific surface area decreased by about 30% as the reaction temperature increased from $800^{\circ}C$ to $900^{\circ}C$.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.92-97
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• 2017

It is widely known that pulsed magnetic field (PMF) is very useful tool to manipulate chemical and physiological processes in human body. The purpose of our study is to observe dynamics of rouleaux patterns of red blood cells (RBC) under PMF. The aggregation of RBCs or rouleaux formation is caused by fibrinogen in blood plasma. The maximum magnetic field intensity is 0.27 T and pulse time of 0.102 msec and pulse repetition rate was 1 Hz. PMF stimulus was applied to the palm of left hand for 5, 10, 15 and 20 min. Live blood analysis was used in vitro in order to quantitatively estimate the velocity of RBC exposed to PMF stimulus. The velocity of stacked-RBC of 10 minute PMF stimulus was increased up to $8{\times}10^{-4}m/sec$, but it decreased rapidly as the time passed. The results of present study have adduced that PMF stimulus on hand provide the improvement of RBC rouleaux formation, increase of RBC's moving velocity as well as low blood viscosity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.603-610
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• 1993

Effects of pine tree(Pinus densiflora) endodermis or china grass leaves(Boehmeria nipponivea) on textural or sensory quality of rice cake were investigated. Rice cakes prepared with the addition of pine tree endodermis or china grass leaves were not remarkably decreased in moisture content during storage. Degree of gelatinization was shown the highest value in the samples 17.28% of pine tree endodermis or china grass leaves added. As a result of the sensory evaluation for the rice cakes, consistency, moistness and cohesiveness were gradually improved with the increase of pine tree endodermis or china grass leaves addition amount. The overall quality was most preferable in the rice cakes prepared with 17.28% of pine tree endodermis or china grass leaves. The detrimental changes were occured in textural quality of the all rice cake samples during storage. Textural quality of rice cakes was higher in pine tree endodermis or china grass leaves addition samples than that of control group. In the texturometer test, hardeness and chewiness decreased in pine tree endodermis or china grass leaves addition samples where as gumminess increased these samples compare to control group.

• Journal of Adhesion and Interface
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• v.8 no.2
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• pp.15-21
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• 2007

To prepare a natural rubber-based pressure-sensitive adhesive (PSA) for protection film of opto- functionalized sheet, natural rubber (NR) was blended with a DCPD type tackifier and three types of aliphatic hydrocarbon resins, respectively. Also, to supply low cohesion strength of NR, in the fixed ratio of tackifier, synthetic rubber, styrene-isoprene-styrene (SIS) block copolymer was blended with NR as a function of SIS contents. PSA performance of prepared PSAs was evaluated using probe tack and peel strength. Probe tack of NR/tackifier blends was increased with increasing tackifier contents, and showed maximum peak. In addition, probe tack of NR/tackifier blends slightly increased with increasing softening point of aliphatic hydrocarbon resins. Their peel strength increased up to 50 wt% of tackifier contents, but in the over contents of tackifier, they showed stick-slip failure mode. Finally, probe tack of NR/SIS/tackifier blends showed the maximum values at 20~40 wt% of tackifier contents, but at 20 wt% of tackifier contents, they showed fibrillation. For this reason, peel strength showed maximum values at 40 wt% of tackifier contents.

• Food Engineering Progress
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• v.13 no.4
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• pp.289-296
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• 2009

The purpose of this study was to investigate the effect of dextrinization methods (dry oven and roaster) and the ratio of dextrinized rice on the quality of Backsulgi during storage. The moisture content significantly increased with increasing the amount of dextrinized rice regardless of dextrinization methods. As the ratio of dextrinized rice increased, the L value of the Backsulgi decreased, but the a and b values increased. The a and b values of dry oven method were higher than those of roaster method due to their thermal denaturalization. However, there were no significant pattern's change in sample's colors during storage. In the texture profiles, the hardness, cohesiveness, gumminess and chewiness significantly decreased with increasing the amount of dextrinized rice depending on the dextrinization methods and the ratios. The time constant (1/k) of the Backsulgi with dextrinized rice comparatively higher than that of control and appeared to be the highest in the Backsulgi formulated by 100% of dextrinized rice. In the sensory evaluation, Backsulgi with dextrinized rice over 30% after 1day storage showed higher value in overall quality and lower value in hardness than control. The addition of 30% dextrinized rice made by roaster showed the most effective on the quality and retrogradation of Backsulgi.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.15 no.1
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• pp.113-125
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• 2004

Effect of microwave radiation on physico-chemical properties of cor'n starches was studied. Waxy com, com and high amylose com starches of varying moisture content(20～35%) were subjected to microwave processing(2450MHz) at $120^{\circ}$ and the experimental starch samples were examined by a X-ray diffractometry, rapid viscosity analyzer(RVA) and. with the samples in temperature was observed and the peaks of high amylose com starches at $2^{\circ}$=5.0, 15.0 and $23.0^{\circ}$, were disappeared indicating the melting of crystallines while those of com and waxy com had not changed. A change in gelatinization pattern was observed in the case of corn starches from type A with nearly no peak-viscosity and breakdown to type C. Except a decreased viscosity, no change was observed in those of waxy com starches.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.113-117
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• 2017

The purpose of this study was to evaluate the effects of rice cultivars (Hangaru, Seolgaeng, Dasan-1 and Anda) on the quality characteristics of rice beer. Hangaru and Seolgaeng which are soft rice varieties, had moisture contents that were 14.48% and 14.62% higher than those of Dasan-1 and Anda, respectively. Dasan-1 and Anda showed higher protein contents than those of the other two varieties. The amylose content of Hangaru was found to be 17.71% lower than that of the other varieties, whereas the reducing sugar content of Hangaru and Seolgaeng was higher than that of Dasan-1 and Anda. Hardness measurements for Hangaru and Seolgaeng were lower than those for Dasan-1 and Anda. Measurements of the alcohol content, pH and color of beers brewed using these rice cultivars revealed no significant difference among the cultivars. However, measurement results for bitterness showed that beers brewed with Hangaru and Seolgaeng had lower bitterness than did the beers brewed with Dasan-1 and Anda. The results of this study indicate that Hangaru and Seolgaeng can be considered as cultivars with brewing qualities suitable for rice beer.

• Journal of Korean Home Economics Education Association
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• v.19 no.4
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• pp.91-117
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• 2007

This study was to compare the contents and practical problems addressed, the process of teaching-learning method, and evaluation method of Korean Home Economics curriculum and of the Oregon and Ohio's Practical Problem Focused Family & Consumer Sciences Curricula. The results are as follows. First, contents of Korean curriculum are organized by major sub-concepts of Home Economics academic discipline whereas curricular of both Oregon and Ohio states are organized by practical problems. Oregon uses the practical problems which integrate multi-subjects and Ohio uses ones which are good for the contents of the module by integrating concerns or interests which are lower or detailed level (related interests). Since it differentiates interest and module and used them based on the basic concept of Family and Consumer Science, Ohio's approach could be easier for Korean teachers and students to adopt. Second, the teaching-learning process in Korean home economics classroom is mostly teacher-centered which hinders students to develop higher order thinking skills. It is recommended to use student-centered learning activities. State of Oregon and Ohio's teaching-learning process brings up the ability of problem-solving by letting students clearly analyze practical problems proposed, solve problems by themselves through group discussions and various activities, and apply what they learn to other problems. Third, Korean evaluation system is heavily rely on summative evaluation such as written tests. It is highly recommended to facilitate various performance assessment tools. Since state of Oregon and Ohio both use practical problems, they evaluate students mainly based on their activity rather than written tests. The tools for evaluation include project documents, reports of learning activity, self-evaluation, evaluation of discussion activity, peer evaluation in a group for each students for their performance, assessment about module, and written tests as well.