• 한국식품영양과학회지
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• 제19권3호
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• pp.234-238
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• 1990

The effects of salt concentration immersion time in a salt solution prior to air dehydration and heating of air temperature during dehydration upon the browning reaction and pyruvic acid content of air dried garlics to a 6.5% moisture content(wet basis) were analyzed by a response surface methodology(RSM), Those values were also predicted by using a second degree polynomial regression model. Heating of air temperature was the most significant factor affecting the both browning reaction and pyruvic acid content. Salt concentration had more influence to browning reaction than immersion time whereas immersion time was more impor-tant factor than salt concentration on a retention of pyruvic acid sugested different processing conditions. While the processing conditions to minimize the browning reaction(O.D=0.009) were 0.3% of salt solution 9 min of immersion time and 5$0^{\circ}C$ of air temperature compared to control(O.D=0.022) of air dehydration at 5$0^{\circ}C$ Pyruvic acid contents were maximized(174 $\mu$mole/g garlic solid) at the 0.1% of salt solution 3 min of immersion time and 5$0^{\circ}C$ of air temperature compared to control(147 $\mu$mole/g garlic solid) of air dehydration at 5$0^{\circ}C$

• Korean Chemical Engineering Research
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• 제56권3호
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• pp.416-420
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• 2018

A comprehensive kinetic study has been conducted on dimethyl carbonate synthesis by transesterification reaction of ethylene carbonate with methanol. An alkali base metal (KOH) was used as catalyst in the synthesis of DMC, and its catalytic ability was investigated in terms of kinetics. The experiment was performed in a batch reactor at atmospheric pressure. The reaction orders, the activation energy and the rate constants were determined for both forward and backward reactions. The reaction order for forward and backward reactions was 0.87 and 2.15, and the activation energy was 12.73 and 29.28 kJ/mol, respectively. Using the general factor analysis in the design of experiments, we analyzed the main effects and interactions according to the MeOH/EC, reaction temperature and KOH concentration. DMC yield with various reaction conditions was presented for all ranges using surface and contour plot. Furthermore, the optimal conditions for DMC yield were determined using response surface method.

• 셀메드
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• 제6권2호
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• pp.14.1-14.5
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• 2016

Taemyeongcheong (TMC) is Korean traditional extracted drink with various health ingredients. TMC has been used to treat hepatic damage, obesity, gastritis, and colitis. However, the role of TMC on allergic reaction has not been studied yet. In this study, we investigated the anti-allergic effects of TMC against a compound 48/80-induced systemic anaphylactic reaction and IgE-mediated passive cutaneous anaphylaxis (PCA). TMC significantly inhibited the compound 48/80-induced systemic anaphylactic reaction and IgE-mediated PCA reaction. Furthermore, TMC reduced the levels of interleukin (IL)-1β, IL-4, IL-13, and vascular endothelial growth factor in the serum of mice under PCA reaction. Taken together, these results suggest that TMC can play a useful role as an anti-allergic agent.

• 대한화학회지
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• 제13권4호
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• pp.241-247
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• 1969

The catalytic reaction between carbon monoxide and oxygen was investigated with the various nickel oxide catalysts at different partial pressures of carbon monoxide and oxygen and at reaction temperatures in the region of 120$^{circ}$to 250$^{circ}C$. The reaction has the highest rate with the nickel oxide catalyst which is sintered at low temperature. A reaction mechanism to explain the data is derived. From the Arrhenius equation, the activation energies in the region of experimental temperatures are found to be from 5.49 to 9.15 kcal/mole. The concentration of excess oxygen in the nickel oxide seems to vary according to the sintering temperatures and periods and is the controlling factor in determining the type of kinetics followed by the catalytic reaction.

• 방사성폐기물학회지
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• 제19권2호
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• pp.225-231
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• 2021

The reaction between Li₂CO₃ and Cl₂ was investigated to verify its occurrence during a carbon-anode-based oxide reduction (OR) process. The reaction temperature was identified as a key factor that determines the reaction rate and maximum conversion ratio. It was found that the reaction should be conducted at or above 500℃ to convert more than 90% of the Li₂CO₃ to LiCl. Experiments conducted at various total flow rate (Q) / initial sample weight (W_i) ratios revealed that the reaction rate was controlled by the Cl₂ mass transfer under the experimental conditions adopted in this work. A linear increase in the progress of reaction with an increase in Cl₂ partial pressure (pCl₂) was observed in the pCl₂ region of 2.03-10.1 kPa for a constant Q of 100 mL·min^-1 and W_i of 1.00 g. The results of this study indicate that the reaction between Li₂CO₃ and Cl₂ is fast at 650℃ and the reaction is feasible during the OR process.

• 한국콘텐츠학회논문지
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• 제12권6호
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• pp.371-379
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• 2012

본 연구는 부산 경남지역의 치과내원환자를 대상으로 주관적 구강건강인식과 상태 그리고, 치과진료 분야에 치과공포수준을 파악하여 추후 치과진료 시 치과공포를 줄일 수 있는 방안을 마련하여, 구강건강의 향상과 더불어 삶의 질 향상에 기초자료로 개발하고자 한다. DFS의 전체 문항에서 100점 만점에 남자(44.9점)보다 여자(53.1점)에서 공포감이 모두 높게 나타났다. 치료종류에 따른 공포수준은 임플란트 치료 치료회피요인(p=0.015), 교정치료 치료회피요인(p=0.002), 생리적 반응요인(p=0.009), 보철치료 치료회피요인(p=0.014), 신경치료 치료회피요인(p=0.005), 생리적 반응요인(p=0.017), 치주치료 치료회피요인(p=0.013), 생리적 반응요인(p=0.004), 정기검진을 받지 않는 경우 치료회피요인(p=0.027)이 높았다. 구강증상에 대하여 인지하고 있는 개수가 많을수록 치료회피요인(p=0.001), 자극반응요인(p=0.002), 생리적반응요인(p=0.005)로 높았다. 이상의 결과에서 치과공포를 줄이기 위해서는 정기검진과 예방적 처치를 위한 다양한 프로그램개발 및 구강보건교육을 실시해야 할 것이다.

• 한국안전학회지
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• 제27권5호
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• pp.77-87
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• 2012

Compared to a batch reactor, where all reactants are initially charged to the reactor, the semi-batch reactor presents serious advantages. The feed of at least one of the reactants provides an additional way of controlling the reaction course, which represents a safety factor and increases the constancy of the product quality. The aim of this study was to investigate the characteristics of thermal hazard such as a feed time, catalysis concentration and solvent concentration in methylthioisocyanate(MTI) synthesis reaction process. The experiments were carried out by the Multimax reactor system and Accelerating rate calorimeter(ARC). The MTI synthesis reaction process has many reaction factors and complicated reaction mechanism of multiphase reaction. Through this study, we can use as a tool for assessment of thermal hazard of other reaction processes by applying experiment method provided.

• 한국지반공학회논문집
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• 제36권11호
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• pp.7-20
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• 2020

본 연구에서는 말뚝기초를 대상으로 지반조건을 고려한 동적 수평지반반력계수를 제안하기 위하여 수치해석을 수행하였다. 3차원 유한차분 프로그램을 사용하여, 다양한 지반의 전단파 속도에 따라 동적수치해석을 수행하였다. 수치해석 결과로부터 동적 p-y 곡선을 도출하여 동적 수평지반반력계수를 계산하는 데 필요한 보정계수(α)를 산정하였다. 분석결과, 본 연구에서 산정된 보정계수(α)는 기존 도로교 설계기준(2015)에 제시된 획일적인 값(α=2)이 아니라 지반의 전단파 속도와 구속압에 매우 큰 영향을 받는 것을 알 수 있었으며 이를 고려한 함수식으로 제안하였다. 제안된 α의 적용성 분석을 위해 서로 다른 해석 기법(등가정적해석방법과 동적해석방법)에서의 적용성을 비교하였다. 그 결과, 제안된 보정계수(α)를 사용하는 방법은 기존 동적 수평지반반력계수를 사용하는 방법에 비해 지반-말뚝 시스템의 수평거동 특성을 비교적 적절하게 예측함을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제39권1호
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• pp.11-20
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• 2014

Purpose: Walking type cultivator used for weeding generated excessive handle vibration as well as bouncing motion depending on the weeding speed. This research was conducted to define a design factor of the rotary weeding blades for reducing soil reaction forces as well as hand vibration. Methods: The motion and forces acting on the rotary blades were reviewed to find out the most influencing parameter on hand vibration. The installation angle (IA) of the blade was selected and analyzed to determine the condition of no reaction force less. For removing the unnecessary upward soil reaction, the design factor theory of weeding blade was suggested based on geometrics and dynamics. For evaluation of design factor theory, the experiment in situ was performed base on ISO 5349:1. The vibration $a_{hv}$ and theoretical value $X_{MF}$ were compared with two groups that one was positive group ($X_{MF}$ > 0) and the other was negative group ($X_{MF}$ < 0). Results: $X_{MF}$ was derived from rotational velocity, forward velocity, disk diameter, weeding depth, blade's width and IA of blade. Two groups had significant difference (p < 0.05). In aspect of the group mean total exposure duration, positive group was 17.53% bigger than negative group. When disk radius 100, 150 and 200 mm, minimum IAs were $4{\sim}27^{\circ}$, $3{\sim}15^{\circ}$ and $2{\sim}10^{\circ}$, respectively. A spread sheet program which calculated XMF was developed by Excel 2013. Conclusions: According to this result, minimum IA of weeding blade for soil reaction reduction could be obtained. For reduction hand-arm vibration and power consumption, minimum IA is needed.

• Applied Microscopy
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• 제44권1호
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• pp.21-29
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• 2014

Retinal glial responses to hypertensive glaucomatous injury were spatiotemporally surveyed. Retinas as a whole or vertical sections were processed for anti-glial fibrillary acidic protein (GFAP), anti-Iba1, anti-nerve growth factor (NGF), and anti-tumor necrosis factor (TNF)-${\alpha}$ immunohistochemistry for confocal microscopic analyses. The optic nerve head of paired controls was processed for electron microscopy. GFAP positive astrocytes appeared in the nerve fiber layer in the glaucomatous and control retinas, changing from fine protoplasmic to stout fibrous parallel to glaucomatous duration. Iba1 positive microglia appeared in both retinas, and enormous reaction appeared at the latest glaucomatous. M$\ddot{u}$ller reaction detected by GFAP reactivity expanded from the end feet to whole profile following to duration in the glaucomatous. NGF reactivity expended from the end feet to the proximal radial processes of the M$\ddot{u}$ller cells in both retinas according to glaucomatous duration. TNF-${\alpha}$ immunoreactivity in the nerve fiber layer was stronger in both the glaucomatous and controls than in the normal, and exceptionally at the latest glaucomatous was even lower than the normal. The astrocytes in the optic nerve head are interconnected with each other via gap junction. These results demonstrate that astrocyte reaction propagates to the contralateral via physical links, and TNF-${\alpha}$ is correlated with NGF production for neuroprotection in response to hypertensive glaucomatous injury.