• Title/Summary/Keyword: Thermal effect

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A Study on Characteristics of Heat Storage and Emission of Apartment Structures in Winter Season (겨울철 난방시 아파트 구조체의 축방열 특성에 대한 연구)

  • Cho, Keun-Je;Chang, Hyun-Jae
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.208-213
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    • 2011
  • In the former study, it is obtained that thermal storage effect of the apartment structure is the disadvantage to maintain comfort indoor thermal environment. However, because the thermal storage effect can be changed of its aspect in heating season, field measurement at the same apartment with the measurement in summer season was conducted in winter season. As results, thermal storage effect of apartment structure was the disadvantage in winter season, too.

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The Dielectric Characteristics of Low Density Polyethylene Film due to Thermal Treatment Effect (열처리효과에 따른 저밀도 폴리에틸렌 박막의 유전특성)

  • 김왕곤;가출현;이용우;홍진웅
    • Journal of the Korean Society of Safety
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    • v.11 no.1
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    • pp.67-74
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    • 1996
  • In order to investigate the effect and reliability coming up to properties of the matter due to the change of solid structure in dielectrics, the effect of dielectric characteristics for thermal treated LDPE film was made researches. Specimens of LDPE with thickness 100 [$\mu\textrm{m}$] were investigated into the change of solid structure by ageing. Thermal treated specimen were made, that were after applying heat at 100 [$^{\circ}C$] for 1 [hour] \circled1 air-cooled specimen slowly, \circled2 water-cooled specimen under the ,com temperature, \circled3 liquid nitrogen gas-cooled specimen rapidly. With specimen of thermal treated three types turn out and original, it was for dielectric characteristics to be experimented in the temperature range of 20~120 [$^{\circ}C$], frequency range of 30~1.5${\times}10^5/$[Hz], appling voltage from 300 to 1500[㎷]. Consequently, the degree of crystallinity was changed with 49~57 [%] according to the thermal treatment. In case of frequency, 100 [Hz], on the thermal dependance in dielectric characteristics, tan decreases due to cooling method.

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Effect of Bentonite Type on Thermal Conductivity in a HLW Repository

  • Lee, Gi-Jun;Yoon, Seok;Cho, Won-Jin
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.3
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    • pp.331-338
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    • 2021
  • Extensive studies have been conducted on thermal conductivity of bentonite buffer materials, as it affects the safety performance of barriers engineered to contain high-level radioactive waste. Bentonite is composed of several minerals, and studies have shown that the difference in the thermal conductivity of bentonites is due to the variation in their mineral composition. However, the specific reasons contributing to the difference, especially with regard to the thermal conductivity of bentonites with similar mineral composition, have not been elucidated. Therefore, in this study, bentonites with significantly different thermal conductivities, but of similar mineral compositions, are investigated. Most bentonites contain more than 60% of montmorillonite. Therefore, it is believed that the exchangeable cations of montmorillonite could affect the thermal conductivity of bentonites. The effect of bentonite type was comparatively analyzed and was verified through the effective medium model for thermal conductivity. Our results show that Ca-type bentonites have a higher thermal conductivity than Na-type bentonites.

Fiber Optic Temperature Sensor Based on the Thermal Expansion Effect of Fused Optical Fiber Coupler Fixed on a Al Support (알루미늄 지지대에 고정된 융착 광섬유 커플러의 열팽창을 이용한 온도 센서)

  • Kim, Kwang Taek
    • Journal of Sensor Science and Technology
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    • v.26 no.5
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    • pp.338-341
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    • 2017
  • We have investigated a temperature sensor on a thermal expansion effect of a fused optical fiber coupler. Both side of the fused tapered region of the coupler were fixed on a metal support to induce the high thermal expansion effect. The sensor showed that the peak coupling wavelengths were shifted to shorted wavelength region with increased of environmental temperature. The sensitivity of the sensor was $0.12nm/^{\circ}C$.

A Study on Thermal Effect and Medication Compliance of Red Ginseng Extract (홍삼의 온열 효과와 복약 순응도에 관한 연구)

  • Choi, Min-Sun;Jeong, Jae-Cheol;Park, Jang-Kyung;Ahn, Hong-Yeop;Kim, Dong-Il
    • Journal of Oriental Medical Thermology
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    • v.7 no.1
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    • pp.44-54
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    • 2009
  • Purpose: To evaluate thermal effect and medication compliance of red ginseng extract. Methods: Randomized, double-blind, placebo-controlled, cross-over clinical study was performed. Twenty four healthy, married women aged 30-45 years with FSFI score below 25 were randomly divided into two groups; red ginseng group(N=12) and placebo group(N=12). During the first 6-week period (Study1), each group was dosed with red ginseng or placebo twice a day. Before starting the second 6-week period(Study2), a crossover design was chosen with a 2-week break(Washout period). Interchanging two groups after Washout period, red ginseng and placebo were dosed to each group. The efficacy of thermal effect was measured with subjective warm sensation scale and lower abdomen temperature by Digital Infrared Thermographic imaging(DITI) before and after each 6-week period. A medication compliance was assessed after each 6-week period and the correlation medication compliance between Sasang Constitution and subjective warm sensation was analyzed. Results: Overall 23 participants completed the study. In subjective warm sensation scale, after taking placebo, all participants exhibited an improving trend, but there was no significant difference. In lower abdomen temperature by DITI, statistically significant objective thermal effect of red ginseng was also not shown. A medication compliance was higher in Yin constitution(Taeumin, Soeumin), and showed an upward trend with decreasing subjective warm sensation. But no statistically significant difference was exhibited. Conclusion: Statistically significant thermal effect of red ginseng was not shown in this study. We anticipate if a long-term clinical trial is practiced, significant thermal effect of red ginseng will be shown.

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Effect of the Thermal Lensing on stable Region, Beam Waist and Astigmatic Compensation of Z-fold Cr4+ : YAG laser Cavity (Cr4+ : YAG 레이저에서 열 렌즈 효과에 따른 공진기의 안정영역과 빔 허리 및 비점수차의 보상)

  • Lee, Bong-Yeon
    • Korean Journal of Optics and Photonics
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    • v.17 no.5
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    • pp.447-454
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    • 2006
  • We obtained analytic solutions of boundary conditions to the stable region of Z-fold $Cr^{4+}$ : YAG laser cavity when the conditions are with and without thermal tensing effect. Also we investigated the influence of the thermal tensing effect on the stability of cavity, beam waist, and astigmatic compensation using aberration transformation matrices. The thermal tensing effect almost has no influence on the stable region of the cavity when the crystal is located in the middle of two concave mirrors and when the distances from the concave mirror to the reflecting mirror and the output coupler are the same. The beam waist, however, is affected more in a tangential plane than in a sagittal plane, and so it is difficult to have astigmatic compensation when the thermal tensing effect exists. This result means that the thermal tensing effect should be considered even for the Kerr-lens mode-locking.

A Study on Thermal Effect and Medication Compliance of Red Ginseng Extract (홍삼의 온열 효과와 복약 순응도에 관한 연구)

  • Choi, Min-Sun;Jeong, Jae-Cheol;Park, Jang-Kyung;Ahn, Hong-Yeop;Kim, Dong-Il
    • The Journal of Korean Obstetrics and Gynecology
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    • v.22 no.3
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    • pp.223-235
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    • 2009
  • Purpose: To evaluate thermal effect and medication compliance of red ginseng extract. Methods: Randomized, double-blind, placebo-controlled, cross-over clinical study was performed. Twenty four healthy, married women aged 30-45 years with FSFI score below 25 were randomly divided into two groups; red ginseng group(N=12) and placebo group(N=12). During the first 6-week period (Study1), each group was dosed with red ginseng or placebo twice a day. Before starting the second 6-week period(Study2), a crossover design was chosen with a 2-week break(Washout period). Interchanging two groups after Washout period, red ginseng and placebo were dosed to each group. The efficacy of thermal effect was measured with subjective warm sensation scale and lower abdomen temperature by Digital Infrared Thermographic imaging(DITI) before and after each 6-week period. A medication compliance was assessed after each 6-week period and the correlation medication compliance between Sasang Constitution and subjective warm sensation was analyzed. Results: Overall 23 participants completed the study. In subjective warm sensation scale, after taking placebo, all participants exhibited an improving trend, but there was no significant difference. In lower abdomen temperature by DITI, statistically significant objective thermal effect of red ginseng was also not shown. A medication compliance was higher in Yin constitution(Taeumin, Soeumin), and showed an upward trend with decreasing subjective warm sensation. But no statistically significant difference was exhibited. Conclusion: Statistically significant thermal effect of red ginseng was not shown in this study. We anticipate if a long-term clinical trial is practiced, significant thermal effect of red ginseng will be shown.

Contribution of thermal-hydraulic validation tests to the standard design approval of SMART

  • Park, Hyun-Sik;Kwon, Tae-Soon;Moon, Sang-Ki;Cho, Seok;Euh, Dong-Jin;Yi, Sung-Jae
    • Nuclear Engineering and Technology
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    • v.49 no.7
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    • pp.1537-1546
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    • 2017
  • Many thermal-hydraulic tests have been conducted at the Korea Atomic Energy Research Institute for verification of the SMART (System-integrated Modular Advanced ReacTor) design, the standard design approval of which was issued by the Korean regulatory body. In this paper, the contributions of these tests to the standard design approval of SMART are discussed. First, an integral effect test facility named VISTA-ITL (Experimental Verification by Integral Simulation of Transients and Accidents-Integral Test Loop) has been utilized to assess the TASS/SMR-S (Transient and Set-point Simulation/Small and Medium) safety analysis code and confirm its conservatism, to support standard design approval, and to construct a database for the SMART design optimization. In addition, many separate effect tests have been performed. The reactor internal flow test has been conducted using the SCOP (SMART COre flow distribution and Pressure drop test) facility to evaluate the reactor internal flow and pressure distributions. An ECC (Emergency Core Coolant) performance test has been carried out using the SWAT (SMART ECC Water Asymmetric Two-phase choking test) facility to evaluate the safety injection performance and to validate the thermal-hydraulic model used in the safety analysis code. The Freon CHF (Critical Heat Flux) test has been performed using the FTHEL (Freon Thermal Hydraulic Experimental Loop) facility to construct a database from the $5{\times}5$ rod bundle Freon CHF tests and to evaluate the DNBR (Departure from Nucleate Boiling Ratio) model in the safety analysis and core design codes. These test results were used for standard design approval of SMART to verify its design bases, design tools, and analysis methodology.

A Study on the Thermal Phenomena and Stack Effect of Nude Elevator Shaft of High Rise Building that used CFD (CFD를 이용한 초고층빌딩 누드 엘리베이터의 온열 및 연돌현상에 관한 연구)

  • Park, Jung-Han
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1059-1064
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    • 2008
  • The present study is to reduce the thermal phenomena and stack effect of nude elevator of the high-rise building used CFD simulation. Since many High-rise buildings used the curtain-wall glass, thermal phenomena and stack effect can easily occur at hot and cold season, respectively. The simulation has been conducted and verified for the effects of the amount of suppling air to the environment of the inside nude elevator shaft. The results of simulations show that the problems due to the thermal and stack effect will be reduced by enforced ventilation or natural ventilation and those will be presented by temperature and velocity profiles and pressure differences.

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Effect of added mesophase pitch during the pitch synthesis reaction of PFO

  • Kim, Ji Hong;Kim, Jong Gu;Lee, Chul Wee;Lee, Ki Bong;Im, Ji Sun
    • Carbon letters
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    • v.23
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    • pp.48-54
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    • 2017
  • This research considers the effect of added mesophase pitch (MP) as an additive during the pitch synthesis reaction of pyrolyzed fuel oil (PFO). Two effects are generated by adding MP. One is an enhancement of thermal stability due to the high thermal property of the additive; the other is that the volatile compounds that were removed by vaporization of PFO during the thermal reaction can participate in the pitch synthesis reaction ($PFO{\rightarrow}pitch$) more efficiently. The effect differs according to the amount of the additive. When the amount of the additive is less than 7 wt%, the first effect is dominant, whereas the second effect is dominant when the additive amount exceeds 10 wt%.