• 한국초전도ㆍ저온공학회논문지
• /
• 제16권1호
• /
• pp.32-35
• /
• 2014

Recently, many researches on the system of superconducting power supply and superconducting magnetic energy storage (SMES) using high temperature superconducting (HTS) tapes has been progressed. Those kinds of superconducting devices use the heater trigger switches that have a control delay problem at moments of heating up and cooling down. One way to reduce the time delay is using a different HTS tape at trigger part. For example, HTS tape having lower critical temperature can reduce time delay of heating up and heating down stage for heater trigger operation. This paper deals with resistances joint with different kinds of HTS tapes which have different properties to verify usefulness of the suggested method. Three kinds of commercial HTS tapes with different specifications are selected as samples and two kinds of solders are used for comparison. Joint is performed with temperature and pressure controllable joint machine and the joint characteristics are analyzed under the repeatable conditions.

• 한국가스학회:학술대회논문집
• /
• 한국가스학회 2002년도 추계학술발표회 논문집
• /
• pp.111-118
• /
• 2002

• Food Science and Biotechnology
• /
• 제17권6호
• /
• pp.1387-1390
• /
• 2008

This study evaluated the effects of heat treatment on antioxidant activity of Rehmannia radix Libosch (RRL). RRL was heated at various temperatures ($110-150^{\circ}C$) for various times (1-5 hr), and the total polyphenol, flavonoid content, and antioxidant activity were investigated. With increased heating temperature and exposure time, total content of polyphenol, flavonoid, as well as antioxidant activity increased. The highest total polyphenol and flavonoid contents were 21.65 and 3.56 mg/g, respectively, these values were occurred after heating for 3 hr at $150^{\circ}C$ (RRL was 5.09 and 0.83 mg/g, respectively). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was highest value of 83.46% after heating for 3hr at $150^{\circ}C$. The 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging activity was highest value of 20.43mg ascorbic acid (AA) eq/g after heating for 2 hr at $150^{\circ}C$. There were highly significant differences in the total polyphenol, flavonoid content, and antioxidant activity among heating temperatures and times (p<0.001), with heating temperature having the greater effect.

• Applied Microscopy
• /
• 제47권3호
• /
• pp.208-213
• /
• 2017

The microstructural changes in Co nanoparticles and an Au-10at.%Pd thin film have been investigated using an in situ heating holder with a micro-electro-mechanical system (MEMS). In Co nanoparticles, two phases (face-centered cubic and hexagonal close-packed crystal structures) were found to coexist at room temperature and microstructures at temperatures, higher than $1,000^{\circ}C$, were observed with a quick response time and significant stability. The actual temperature of each specimen was directly estimated from the changes in the lattice spacing (Bragg-peak separation). For the Au-10at.%Pd thin film, at a set temperature of $680^{\circ}C$, the actual temperature of the sample was estimated to be $1,020^{\circ}C{\pm}123^{\circ}C$. Note that the specimen temperature should be carefully evaluated because of the undesired effects, i.e., the temperature non-uniformity due to the sample design of the MEMS chip, and distortion due to thermal expansion.

• 한국지반환경공학회 논문집
• /
• 제18권11호
• /
• pp.35-40
• /
• 2017

한랭지역에 건설된 터널은 낮은 기온으로 인하여 콘크리트 라이닝 배면의 동결이 발생하게 되며, 콘크리트 라이닝의 손상을 발생시켜 터널구조물의 내구성을 감소시킨다. 터널 라이닝 배면 지반의 동결을 억제시키기 위하여 터널 라이닝 표면에 발열체를 부착하고 일정시간 동안 발열시켜 콘크리트 라이닝 내부의 온도변화를 측정하였다. 냉동챔버를 제작하여 현장현황을 모사하고 발열체는 탄소나노튜브(CNT, Carbon Nano Tube) 재료를 플레이트로 제작하여 표면에 부착하고 전기공급을 통해 발열시켰다. 발열체를 발열시킴에 따라 콘크리트 라이닝의 내부 위치별 온도변화 분포를 측정하였으며, 외기온도 및 발열온도의 유지시간에 따른 영향을 분석하였다.

• 한국축산식품학회지
• /
• 제21권3호
• /
• pp.265-271
• /
• 2001

We investigated changes of immunoglobulin G (IgG) concentrations by heating and drying condition. Also it is performed to group for commercial product by promoting of IgG preservation and reducing of protein denaturation. The result was that content of IgG in colostrum was higher than normal milk. Especially, IgG content of colostrum within 12 hrs after parturition was over 44.67mg/ml and it is 60 times of normal milk. IgG contents was reduced rapidly according as passage of the time. IgG content of the sample heating at 30min at 65$^{\circ}C$ was still a little higher that heating for 10sec at 72$^{\circ}C$. IgG denaturation of heat treatment at 100$^{\circ}C$ for 10sec was lower than at 85$^{\circ}C$ for 30min. We investigated the changes of IgG concentrations of kinds of market milk different with heating processing. This result showed that IgG denaturation ratio by ultra high temperature pasteurization (UHT) was higher than long time low temperature pasteurization (LTLT). On the other hands, IgG content by spray drying was 14.5mg/g and freezing drying was 10.8mg/g. It showed that denaturation of protein content by freezing drying was more than spray drying.

• Nuclear Engineering and Technology
• /
• 제54권2호
• /
• pp.469-478
• /
• 2022

Tritium was extracted from tritium-contaminated aluminum samples by heating it in a high-temperature furnace at 200, 300, or 400 ℃ for 15 h. The extracted tritium was analyzed by using a liquid scintillation counter (LSC); the sample thicknesses were 0.4 and 2 mm. The differences in tritium extraction over time were also investigated by cutting aluminum stick samples into several pieces (1, 5, 10, and 15) with the same thickness, and subsequently heating them. The results revealed that there are most of the hydrated material based on tritium on the surface of aluminum. When the temperature was increased from 200 or 300 ℃-400 ℃, there are no large differences in the heating duration required for the radioactivity concentration to be lower than the MDA value. Additionally, at the same thickness, because the surface of aluminum is only contaminated to tritiated water, cutting the aluminum samples into several pieces (5, 10, and 15) did not have a substantial effect on the tritium extraction fraction at any of the applied heating temperatures (200, 300, or 400 ℃). The proportion of each tritium-release materials (aluminum hydrate based on tritium) were investigated via diverse analyses (LSC, XRD, and SEM-EDS).

• 한국자동차공학회논문집
• /
• 제5권1호
• /
• pp.120-128
• /
• 1997

The variations of the temperature field in a passenger compartment were measured by using a HSI true color image processing system and TLC(Thermochromic Liquid Crystal) solution. This temperature measurement technique was proved to be useful for analyzing the ventilation flow. The flow field in the passenger compartment was visualized using a particle streak method with pulsed laser light sheet. The temperature field and flow field in the passenger copartment were affected significantly by the ventilation mode. The panel-vent mode heating had shorter elapse time to reach a uniform temperature than the foot-vent mode under the same ventilation condition and nonuniformity inside the passenger compartment could be minimized effectively by using the bilevel heating mode. The temperature increase rate in the rear passenger compartment was iower than the front compartment, especially in the vicinity of the rear seat occupants' knee level.

• 한국식품영양학회지
• /
• 제23권3호
• /
• pp.419-427
• /
• 2010

The focus of the current study was to investigate the physicochemical properties of a corn starch-sponge matrix prepared at a low concentration below gel forming by freeze-drying. The effect of variables(starch concentration, heating temperature, and heating hold time) on the physicochemical properties of the samples was analyzed by response-surface methodology. Regression models on the properties of samples such as hardness, springiness, and water solubility index(WSI) showed high correlation coefficients(r>0.95) and significant F values, but regression models for the other properties(swelling power, apparent viscosity, reducing sugar content, and digestibility) showed them to have relatively low significance. Sample hardness of sample showed the highest value at condition of $90^{\circ}C$ and 5%, whereas springiness was at a maximum at $130^{\circ}C$ and 5%. Also, at 1% of starch concentration, mechanical properties were greatly decreased as the relative humidity increased, compared with the 3% and 5%, especially in the hardness of samples. The WSI showed an increasing trend with heating temperature regardless of starch concentration. Overall, the physicochemical properties of freeze-dried corn starch-sponge matrix were influenced much more by starch concentration and heating temperature than by heating hold time. The results of this study show that the basic properties of freeze-dried corn starch-sponge matrix can be used for the specific food applications or as a functional material for its stability.

• Journal of Biosystems Engineering
• /
• 제29권1호
• /
• pp.45-52
• /
• 2004

The chestnut is a well-blown and important forest product in Korea. The annual production of chestnut is about 95,000 tons and its cultivating area is 80,000 ha. However, the peeling process of outer and inner skins of chestnut is very difficult due to hardness and adhesiveness of chestnut skin. The purpose of this study was to develop a prediction model for flame peeling characteristics of domestic chestnuts, and to evaluate an optimization model to determine the operation conditions of the chestnut flame peeling system. The results of this study were summarized as follows. It was found that the flame peeling characteristics of domestic chestnuts were by the flame temperature, and the flame time. The peeling ratio and the heating depth were increased as the flame temperature and the flame time were increased. The peeling ratio and the heating depth were increased linearly when those were less than 85 % and 2 mm respectively. As the hardness of chestnut shell was decreased, the peeling ratio was increased. A simulation model was developed to predict the peeling ratio and the heating depth based on the hardness of the chestnut shell, the flame temperature, and the flame time of the peeling system. The model was evaluated by comparing the measurement and the prediction of the peeling ratios and heating depths, and showed the good relationship.