• 한국결정성장학회지
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• 제12권2호
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• pp.63-67
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• 2002

부유대역법을 이용하여 직경 Langasite 단결정을 Ar과 $O_2$가 혼합된 가스의 분위기에서 성장시켰으며, 그때 성장속도는 각각 1.5 mm/hr, 회전속도는 15rpm이었고, 성장된 결정은 투명한 짙은 오렌지색을 가졌다. 성장된 결정은 c 축 방향으로 성장되었으며, 길이 방향의 조성변동이 없이 성장한 것을 확인할 수 있었고, 성장된 결정은 $La_{3.10}Ga_{4.73}Si_{1.17}O_{14}$의 조성을 가지고 있었다. 500nm 부근의 흡수밴드는 성장된 결정의 오렌지빛과 관계가 있는 것을 확인할 수 있었으며, 계산된 Langasite의 활성화에너지는 0.23eV이었고, $300^{\circ}C$ 이상의 온도에서 PTC의 특성을 나타내는 것을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제43권3호
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• pp.237-246
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• 2018

Purpose: This study (a) investigated the effect of microwave power intensity and sample thickness on microwave drying characteristics of radish strips, and (b) determined the best-fit drying model for describing experimental drying data, effective moisture diffusivity ($D_{eff}$), and activation energy ($E_a$) for all drying conditions. Methods: A domestic microwave oven was modified for microwave drying and equipped with a small fan installed on the left upper side for removing water vapor during the drying process. Radishes were cut into two fixed-size strip shapes (6 and 9 mm in thickness). For drying experiments, the applied microwave power intensities ranged from 180 to 630 W at intervals of 90 W. Six drying models were evaluated to delineate the experimental drying curves of both radish strip samples. The effective moisture diffusivity ($D_{eff}$) was determined from Fick's diffusion method, and the Arrhenius equation was applied to calculate the activation energy ($E_a$). Results: The drying time was profoundly decreased as the microwave power intensity was increased regardless of the thickness of the radish strips; however, the drying rate of thicker strips was faster than that of the thinner strips up to a certain moisture content of the strip samples. The majority of the applied drying models were suitable to describe the drying characteristics of the radish strips for all drying conditions. Among the drying models, based on the model indices, the best model was the Page model. The range of estimated $D_{eff}$ for both strip samples was from $2.907{\times}10^{-9}$ to $1.215{\times}10^{-8}m^2/s$. $E_a$ for the 6- and 9-mm strips was 3.537 and 3.179 W/g, respectively. Conclusions: The microwave drying characteristics varied depending on the microwave power intensity and the thickness of the strips. In order to produce high-quality dried radish strips, the microwave power intensity should be lower than 180 W.

• Fisheries and Aquatic Sciences
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• 제17권3호
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• pp.325-337
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• 2014

To assess the functional structure of prepro-melanin-concentrating hormone (pMCH), we isolated and cloned pMCH (of-pMCH) mRNA from the brain of the olive flounder, Paralichthys olivaceus, and compared its amino acid sequence with those from other animals. In addition, to examine whether activation of the brain of-pMCH gene is influenced by background color, density, and feeding, we compared pMCH mRNA activities against different background colors (bright and dark) and at different densities (100% PCA and 200% PCA). To examine whether the pMCH gene is related with malpigmentation of blind-side skin and appetite, we compared pMCH gene expression between ordinary and hypermelanic flounders, and between feeding and fasting flounders. The of-pMCH cDNA was 405 bp in the open reading frame [ORF] and encoded a protein of 135 amino acids; MCH was 51 bp in length and encoded a protein of 17 amino acids. An obvious single band of the expected size was obtained from the brain and pituitary by RT-PCR. In addition, of-pMCH gene activity was significantly higher in the bright background only at low density (< 100% PCA) making the ocular skin of fish whitening, and in ordinary fish. However, the gene activity was significantly decreased in dark background, at high density (>200% PCA), and in hypermelano fish. These results suggest that skin whitening camouflage of the flounder is induced by high MCH gene activity, and the density disturbs the function of background color in the physiological color change. Moreover, our data suggest that a low level of MCH gene activity may be related to malpigmentation of the blind-side skin. In feeding, although pMCH gene activity was significantly increased by feeding in the white background, the pMCH gene activity in the dark background was not influenced by feeding, indicating that the MCH gene activity increased by feeding can be offset by dark background color, or is unaffected by appetite. In conclusion, this study showed that MCH gene expression is related to ocular-skin whitening camouflage and blind-skin hypermelanosis, and is influenced by background color and density.

• 대한물리의학회지
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• 제11권2호
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• pp.71-76
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• 2016

PURPOSE: The purpose of this study was to compare isometric contraction of deltoid middle fiber between elastic band and light dumbbell on various shoulder abduction angle. And this study intends to examine the compare with isometric contraction on deltoid middle fiber in various abduction angle of shoulder joint. METHODS: The participants of this study were Korean healthy adult in their 20s (n=60). The 8 channel surface electromyography was used to measure activity of the deltoid middle fiber at isomeric contraction on various abduction angle: $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, $120^{\circ}$ of shoulder joint using elastic band: red color Theraband and dumbbell: 2kg. The data used in the analysis of the present study was the root mean square. RESULTS: The deltoid middle fiber activation was not significantly different between elastic band and dumbbell at each abduction angle. The deltoid middle fiber activation significantly increased as more to increased shoulder abduction angle in elastic band and dumbbell. CONCLUSION: The elastic band and dumbbell was to provide the similarly load to the deltoid middle fiber isometric contraction on all of the shoulder abduction angle. The deltoid middle fiber activation increased as more to increased shoulder abduction angle in elastic band and dumbbell. These results may be an important reference in development of exercise on shoulder joint.

• 대한기계학회논문집B
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• 제36권7호
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• pp.675-681
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• 2012

본 연구는 낮은 회 성분의 함량과 높은 발열량의 특성을 지닌 초청정 석탄의 촤 반응율 특성을 알아보았다. 실험은 DTF(Drop Tube Furnace)를 통해서 다양한 온도조건 하에 산소의 분율을 바꾸어가며 수행하였다. 촤 반응률을 도출하기 위하여 FT-IR을 통해 배기가스(CO, $CO_2$)를 측정하였으며, 이색온도계를 통하여서 입자 온도를 측정하였다. 또한, Arrhenius 경험식을 토대로 초청정 석탄 촤의 활성화 에너지와 빈도인자를 도출하였다. 결과는 초청정 석탄 촤의 반응특성은 온도와 산소 분율이 높아질수록 뚜렷한 증가를 보였고, 초청정 석탄 촤의 활성화 에너지는 역청탄의 수치와 비슷한 값을 보임을 알 수 있었다.

• 대한기계학회논문집B
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• 제37권4호
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• pp.405-413
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• 2013

4 가지 탄종(Gunvor, Glencore, Noble, ECM)의 촤 산화반응 특성을 $900^{\circ}C$에서 $1300^{\circ}C$까지의 노내온도와 대기압 조건에서 DTF(drop tube furnace)를 이용하여 실험하였다. 촤 반응률은 FT-IR 장비로 측정한 CO, $CO_2$ 농도와 이색온도계로 측정한 입자온도를 통해 계산되었고 고회분탄의 활성화에너지(E)와 pre-exponential 상수(A)는 아레니우스 방정식을 기초로 계산되었다. 실험 결과는 석탄의 회분 함량이 늘어남에 따라, 입자온도와 면적반응성이 감소하였다. 이러한 결과는 회분의 큰 열용량, 회분의 기화잠열과 상대적으로 적은 고정탄소의 함량으로 인한 연소성 저하로 사료된다. 결과적으로 고회분탄은 높은 활성화 에너지(E)를 가진다.

• 한국포장학회지
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• 제20권3호
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• pp.85-89
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• 2014

시간-온도이력 지시계(TTI)는 시간-온도 이력에 따라 색이 변하는 작은 라벨로서 온도 의존성이 매우 중요한 성능 요소이다. TTI 색변화와 식품의 Arrhenius 활성화 에너지의 차이(${\Delta}Ea$)에 따른 shelf life 예측 오차를 수리적으로 분석하였다. 수리적 분석을 위하여 TTI의 kinetics는 0차반응, 식품은 1차반응에 해당하며 모두 Arrhenius 온도의존성을 따르는 것으로 가정하였다. TTI의 Ea가 식품보다 크거나 작은 경우 그리고 그 차이의 크기에 의한 효과를 분석하였다. 식품의 Ea가 TTI보다 작은 경우 온도변화에 따른 shelf life를 연산한 결과, TTI의 shelf life(색 변화의 종료 시점)가 식품의 shelf life(부패 시점)에 먼저 도달하였고, 식품이 TTI보다 큰 경우에는 식품이 shelf life에 먼저 도달하는 반대의 결과를 나타내었다. 또한 ${\Delta}Ea$의 크기가 클수록 shelf life의 차이도 크게 증가하였다. 결론적으로 TTI의 Ea가 식품보다 크거나 그 차이가 작을수록 TTI에 의하여 식품의 부패 시점이 안전하거나(shelf $life_{Food}$ > shelf $life_{TTI}$) 정확하게(shelf $life_{Food}{\fallingdotseq}$ shelf $life_{TTI}$) 예측됨을 알 수 있었다.

• 동의신경정신과학회지
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• 제18권3호
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• pp.113-122
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• 2007

The purpose of this study was to evaluate the effects of mental stress measured with heart rate variability(HRV) in healthy adults and to evaluate the effects of laserneedle acupuncture therapy in healthy adults. Methods : 25 healthy volunteers participated in this study. The volunteers were divided randomly, the real laserneedle acupuncture therapy group or the sham laserneedle acupuncture therapy group. First, After 5 minute rest, mental stress was given with stroop color word task and calculation task. And then laserneedle acupuncture therapy or sham laserneedle therapy was done on HT8(少府) for 15 minute. HRV was recorded in 3 period-before stress, after stress, and after laserneedle or sham acupuncture therapy. Results : LF was significantly increased after mental stress. And there was no significant difference between the real laserneedle acupuncture therapy group and the sham laserneedle acupuncture therapy group. Conclusions : This results show that mental stress-stroop color word test and calculation test for 10 minute- contribute to activation of the sympathetic nervous system.

• 동의신경정신과학회지
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• 제20권1호
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• pp.165-176
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• 2009

Objectives : The purpose of this study was to assess the effects of mental stress stimulation and acupucnture applied at HT7 point on heart rate variability (HRV) in normal subjects. Methods : Thirty seven healthy volunteers participated in this study. The volunteers were randomly allocated into two groups. Both groups performed a mental arithmetic stress test and stroop color-word test for 10 minute. Then, acupuncture needles were inserted on HT7 for the study group and on non-acupucnture point for the control group. HRV was recorded three times at test time and before and after acupuncture stimulation. Results : After giving mental stress stimulation to both groups, LF and LF!HF ratio were increased and HF was decreased significantly. After giving acupuncture to study group, LF and LF/HF ratio were decreased and HF was increased, but it was not significant. After giving acupuncture to control group, LF and LF/HF ratio were increased and HF was decreased, but it was not significant. Conclusions : This results show that mental arithmetic stress test and stroop color-word test contribute to activation of the sympathetic nervous system Acupuncture at HT7 could be relatively useful to decrease sympathetic activity and balance autonomic nervous system for those who are under stress.

• Applied Biological Chemistry
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• 제39권3호
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• pp.245-248
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• 1996

식품첨가물로서의 활용가능성을 검색하기위해, 한국산 유색미(Oryza sutiva var. Suwon 415)의 주요색소인 cyanidin 3-히ucoside의 열안정성과 pH 변화에 따른 UV/Vis 스펙트럼의 변화에 대해 연구하였다. 유색미의 안토시아닌 색소는 산성(pH 2.0)과 염기성(pH 9.0) 완충용액에서 각각 강한 적색과 청색을 나타내었고 열에 의한 색소의 분해반응은 20mM phosphate (PH 2.0)와 20mM CHES (pH 9.0) 완충용액에서 $50{\sim}95^{\circ}C$의 온도범위에서 수행되었다. 색소의 분해정도는 UV/Vis 스펙트럼의 변화를 측정하여 결정하였으며, 350nm (pH 2.0)와, 275, 310, 및 405nm (pH9.0)에서 isosbestic를 나타내었다. 이 결과는 색소분해반응이 1차 반응임을 의미한다. 유색미 안토시아닌은 산성조건에서 매우 안정하였고 염기성조건에서도 비교적 안정하였으며, 반감기는 $70^{\circ}C$에서 각각 50.3h과 0.6h이었다. 색소분해반응의 활성화에너지$(E_a)$와 Arrhenius frequence facto(A)는 pH 2.0에서는 26.9kcal $mol^{-1}$과 $6.0{\times}10^{11}\;s^{-1}$이었고, pH 9.0에서는 152Kcal $mol^{-1}$과 $1.4{\times}10^{6}\;s^{-1}$이었다.