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        검색결과 104

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, heating concrete is developed using heating artificial binder, which is more conductive and less expensive than ordinary Portland cement, and the heating effect is verified through laboratory tests and numerical analysis. METHODS : Based on the test results, the range of heat influence of the Heating concrete is calculated through numerical analysis. As a result of the laboratory test, the temperature rises to 58℃ after 10 minutes when heat generation started at the outdoor temperature of 12℃ and the initial temperature of the concrete specimen of 19.1℃. RESULTS : The heating effect is up to 50 cm in width and 90 cm in height centered on the heating concrete through numerical analysis to analyze the influence range of the Heating concrete based on the laboratory test results. However, when the distance from the heating concrete is greater than about 20 cm, the influence becomes very small, and the rate of temperature decrease drops significantly. CONCLUSIONS : From the test and numerical analysis, it can be used as an eco-friendly heating material suitable for concrete pavements.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 자기공명영상 검사 시 와인색 반영구 문신용 염료가 신호 강도에 미치는 영향을 분석하고, 전자파흡수 에 의한 발열 감소 방안을 연구하고자 하였다. 한천과 와인색 반영구 문신용 염료를 이용하여 염료가 퍼진 형태의 팬텀(패드형 팬텀)과 한곳에 뭉친 형태의 팬텀(주사형 팬텀)을 제작하였다. 두 팬텀은 전신용 자기공명영상장치에서 고속스핀에코(turbo spin echo, TSE)와 경사에코(gradient echo, GRE) 계열의 펄스열을 이용하여 2D와 3D로 검사하였다. 검사 후 영상 분석은 팬텀의 몸체, 염료, 공기 방울, 배경을 대상으로 총 720회의 신호강도를 측정하였 다. 전자파흡수에 의한 발열 감소 방안을 확인하기 위해 삽입형 온도계를 팬텀에 삽입 후 검사 전후 팬텀의 온도 변화를 확인하였다. 이때, 대기 온도의 상승 변화를 고려하기 위해 검사 전 대기 온도를 측정하였고, 발열 감소를 위한 방법으로 장치에 내장된 팬, 젖은 거즈, 얼음을 이용하였다. 신호 강도는 2D 영상보다 3D 영상이 좋았고, TSE 계열이 GRE 계열보다 좋았다. 특히 와인색 반영구 문신용 염료가 있는 부위의 신호강도는 공기 때문에 발생한 자화 율 인공물보다 신호강도가 낮게 측정되었다. 온도 측정 검사는 패드형 팬텀과 주사형 팬텀 모두 검사에 의한 온도상 승 효과가 있었으며 온도의 저감을 위한 방법으로 얼음 패드, 팬, 젖은 거즈 순서였다. 본 연구를 통해 와인색 반영구 문신용 염료는 자기공명영상 검사에서 영상과 환자의 안전에 문제를 일으킬 수 있음을 확인하였고, 발열 감소 방안으 로 얼음 패드가 효과적이었다는 것을 확인할 수 있었다.
        4,000원
        4.
        2023.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO/Cu/ZnO (ZCZ) thin films were deposited at room temperature on a glass substrate using direct current (DC) and radio frequency (RF, 13.56 MHz) magnetron sputtering and then the effect of post-deposition electron irradiation on the structural, optical, electrical and transparent heater properties of the films were considered. ZCZ films that were electron beam irradiated at 500 eV showed an increase in the grain sizes of their ZnO(102) and (201) planes to 15.17 nm and 11.51 nm, respectively, from grain sizes of 13.50 nm and 10.60 nm observed in the as deposited films. In addition, the film’s optical and electrical properties also depended on the electron irradiation energies. The highest opto-electrical performance was observed in films electron irradiated at 500 eV. In a heat radiation test, when a bias voltage of 18 V was applied to the film that had been electron irradiated at 500 eV, its steady state temperature was about 90.5 °C. In a repetition test, it reached the steady state temperature within 60 s at all bias voltages.
        4,000원
        8.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we performed thermal safety design of the electric module of a heat-loaded equipment with consideration of its heat dissipation performance. Initially, we calculated the heat dissipation of natural convection to choose a cooling method. Based on this, we found that some modules required forced convection and selected an air-cooling method with an outdoor temperature of 43 degrees Celsius, which is the maximum temperature in Korea. Prior to module production, we performed thermal analysis of each module and proceeded with a design to increase the thermal conductivity of the module as a primary step, and subsequently proceeded with Heat Sink design to maximize the heat dissipation performance. After considering various constraints according to the system requirements and designing the cooling path, we experimentally and analytically secured thermal safety at the operating temperature of the equipment.
        4,000원
        9.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The characteristics of pollutant emission for non-premixed flames with LCG 8000 and LCG 6000 represented as low calorific gases were investigated by numerical simulation. Commercial software (ANSYS 16.2 - FLUENT) is used to predict 2-D pollutant emission with GRI 3.0 detailed reaction mechanism. In addition, the addition of hydrogen to LCG 6000 was also considered. As result, the flame length and temperature of LHVGs were decreased with decreasing calorific value at the same condition. In addition, NO concentration was decreased as temperature decreased. However, CO concentration for LCG 8000 predicted to be slightly higher than that for methane due to the high propane concentration. In the case of LCG 6000 with added hydrogen, the flame length was the shortest and NO concentration was the highest due to the highest flame temperature, but CO concentration decreased rapidly due to the addition of the carbon-free fuel.
        4,000원
        10.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This review summarizes the recent progress in iron-oxide-based heat generators. Cancer treatment using magnetic nanoparticles as a heat generator, termed magnetic fluid hyperthermia, is a promising noninvasive approach that has gained significant interest. Most previous studies on improving the hyperthermia effect have focused on the construction of dopant-containing iron oxides. However, their applications in a clinical application can be limited due to extra dopants, and pure iron oxide is the only inorganic material approved by the Food and Drug Administration (FDA). Several factors that influence the heat generation capability of iron-oxide-based nanoparticles are summarized by reviewing recent studies on hyperthermia agents. Thus, our paper will provide the guideline for developing pure iron oxide-based heat generators with high heat dissipation capabilities.
        4,000원
        14.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the combustion characteristics of low calorific gas (LCG) fuels are investigated by numerical simulation. PREMIXED code is used to predict the flame structure and NO emission with two mechanisms, which are GRI 3.0 and USC II chemical reaction mechanisms for CH4 and LCG 8000 and LCG 6000, respectively. Also, elementary reactions related with production and destruction for OH radical are studied because OH radical is dominant for burning velocity and NO emission. As results, the production and the destruction of OH radical for CH4 and LCG 8000 using GRI 3.0 are dominated by reactions of No. 4, No. 2 and No. 3 and by No. 5, No. 3 and No. 7, respectively. For LCG 6000 using USC II, reactions of No. 3, No. 4 and No. 11 and of No. 7, No. 8 and No. 12 dominates to the production and the destruction, respectively. In addition, NO emissions for LCG gas fuel are generated by thermal NO because the flame temperatures are over 1800 K.
        4,000원
        15.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzes the internal temperature characteristics of heater module using a numerical method when the constant heat flux and heat flux time are applied to the surface heating element. The horizontal and vertical dimensions of heater module are 100mm, and the height is 5mm. The heat flux is 10,000W/m2, 15,000W/m2, and 20,000W/m2, and heat flux time is 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds and 50 seconds, respectively. When the heat flux time was 50 seconds, the temperature of the surface heating element rose to 120.5°C, while the skin epidermis temperature rose 1.7°C. As a result, the surface temperature of the surface heating element increased greatly in the horizontal direction, while it increased low in the depth direction. This is because the heat conduction of the surface heating element is transmitted in the X-Y plane direction, and the thermal conductivity of the pet(polyethylene terephthalate) film and insulation sheet under the surface heating element is very low. when the heat flux at the surface heating element is 20,000W/m2, the skin's epidermal temperature rises up to 0.82℃ compared to 10,000W/m2 and 15,000W/m2.
        4,000원
        19.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the laminar burning velocity of low calorific gas fuels are verified through the comparison and examination of experimental and predicted results. The bunsen burner which has contraction nozzle is used to measure the laminar burning velocity with the cone angle method. In addition, PREMIXED code combined with two mechanism, i.e., the GRI 3.0, and USC II reaction mechanisms is used to predict the laminar burning velocity. As heating value decrease, the laminar burning velocity correspondingly decreases due to inert gases in the fuels. Through the comparison and analysis of the experimental results and the predicted results, it is confirmed that LCF 9000 and LCF 8000 with the GRI 3.0 reaction mechanism and LCF 7000 and 6000 with the USC II reaction mechanism have a similar distribution of laminar burning velocity between the experimental result and the predicted result. This similarity is due to a large amount of propane, which is not suitable for the GRI 3.0 reaction mechanism in LCF 7000 and 6000.
        4,000원
        20.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electric of using in daily life is always exposed to risk of electrical fire and electric shock. Only degree of risk is different, there is no risk free electrical product. Generally, the higher voltage, the risk of electric shock is high. The much electric current, the risk of electrical fire is high. But, we can’t help using electric because of risk and we effort to reduce the risk of electrical fire and electric shock. This study deal with the fire prevention generated on heating equipment using SSR for current.
        4,000원
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