• Title/Summary/Keyword: heat spreading

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A Study on the Pollutant Dispersion over a Mountain Valley Region (I) : Wind Tunnel Experiments (산악 계곡지형에서의 오염확산에 관한 연구(I) :풍동실험)

  • Yoo Seong-Yeon;Shim Woo-Sup;Kim Seogcheol
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.11
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    • pp.1050-1059
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    • 2005
  • Heat and $SF_6$ gas dispersions over a complex terrain were investigated using wind tunnel. The wind speed, temperature and concentration profiles were measured for the 1/1000 scale complicated terrain model in an Eiffel type boundary layer wind tunnel with test section of 2.5m in height and 4.5m in width. The scale model was mounted on the top of a plate which can rotate with respect to the approaching wind. Dispersion processes from a continuous emission source driven by various wind direction were investigated, including plume climbing over the steep up-slope of the mountain and down-spreading toward the lower level of the valley. Extensive dispersion experiment data (wind speeds and concentration profiles) were provided for verification and validation of dispersion models. Under the identical flow and emission conditions, the independently measured profiles of the temperature and $SF_6$ concentration showed an excellent agreement which ensured the credibility of the results.

Study on Thermal Conductive PV(PhotoVoltaic) Backsheet using MgO Masterbatch with High Thermal Conductivity (고열전도도 MgO를 이용한 열전도성 PV(PhotoVoltaic) 백시트의 연구)

  • Kim, Chang-Hee;Jang, Hyun-Tae;Park, Jong-Se;Yoon, Jong-Kuk;Noh, Eun-Seob;Park, Ji-Soo;Koo, Kyung-Wan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.3
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    • pp.448-453
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    • 2018
  • PV module protective film plays an important role in protecting the solar cell from external environment by anti-hydrolysis polyester, UV resistance and mechanical properties. The backsheet was manufactured by using Roll-to-Roll dry laminating process. The backsheet structure is composed of 3 layers, which are PE, PET, and Fluorine polymer films. In this study, we have experimented the variation of thermal conductivities depending on MgO inputs 10% to 25% in order to confirm the dependence of the module efficiencies. High thermal conductive backsheet can increase the module output power efficiency because the heat is dissipated by spreading out the internal heat. Long-term environment weatherability tests were conducted for confirming 25 year reliability in the field such as PCT, UV, and power efficiency degradations. As the evaluation result, high thermal conductivity can be effective for increase of power efficiency of solar panel by using thermal conductive MgO masterbatch.

Alkaline Sizing of Mechanical Pulp

  • Kim, Bong-Yong;Akira Isogai
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.32 no.5
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    • pp.1-7
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    • 2000
  • Alkaline Sizing behavior and mechanism of handsheets, which were prepared from thermomechanical pulp (TMP) with alkylketene dimer (AKD), were studied in terms of the conditions of the handsheet-making. AKD content in the TMP handsheets was increased with increasing of AKD addition level and the addition of a polyamideamine-epichlorohydrin resin (PAE) clearly enhanced AKD retention as well as the resultant sizing performance of TMP handsheets. Although drying of the AKD sized TMP webs at $20^{\circ}C$ led to no or quite low sizing level, but TMP handsheets sized with AKD had higher sizing degrees with increasing of the temperature of heat treatment. Scanning electron microscopic observations of the AKD-sized TMP handsheets showed that AKD emulsion particles were present on pulp fiber surfaces independently without coagulation in the TMP handsheets dried at $20^{\circ}C$. Heat treatment of the AKD-sized handsheets resulted in disappearance of the AKD emulsion particles because of their melting and spreading. The addition of calcium carbonate filler to the TMP suspensions did not influence on AKD content in the TMP handsheets. Nevertheless, their sizing degrees clearly increased by the addition of $CaCO_3$filler. Probably, AKD molecules adsorbed on the $CaCO_3$filler particles contribute to the enhancement of sizing performance. Thus, AKD can give sizing features effectively to the TMP handsheets, when they are made under suitable conditions.

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The Oriental and Occidental bibliographic Study of Psoriasis (乾癬에 對한 東.西醫 文獻的 硏究)

  • Kim, Nam-Kwen;Hwang, Chung-yeon;Lim, Gye-sang
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.12 no.1
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    • pp.154-178
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    • 1999
  • Psoriasis is the recurrent disease of skin and till now its mechanism, pathogenesis and treatment are not clearly discovered. So, like these papers, we must investigate more safety and effective treatment of psoriasis. And I obtained the following condusions from the Oriental and Occidental bibliographic investigation. 1. In Oriental medicine. Baikbi, Pungsun, Eunselbyong, Songpisun, Baikselpung were the other names of Psoriasis. 2. In Occidental medicine, genetic factors, aggravation and inducible factors, biochemical factors, immunologic factors, disorder of epidermal kinetics, vascular malformation of dermis were cosidered to the pathogenic factors of psoriasis. 3. In Oriental medicine, the pathogenic factors of psoriasis were divided two parts. One is exogenous pathogenic factors which including the blood-heat, blood dryness, blood stasis, deficiency of liver and kidney, inharmony of impulsive and appointed pulsation, deficiency of blood. The other is exogenous pathogenic factors which including the wind-evil, wind-wetness, wind-heat, wind-cold, wetness-heat, cold-wetness, heat-evil. 4. In Occidental medicine, external applicative medicine, internal medicine, ultraviolet therapy, ultraviolet - external applicative medicine compound therapy and etc. were used the therapy of psoriasis. 5. In Oriental medicine, clean away heat and cooling blood, aliment the blood and moisturize, activating blood and expelling blood stasis, harmonize and invigorate the liver and kidney, invigorate the kidney, aliment the blood and moisturize the skin, aliment the blood and expelling the wind, expelling the wind and wetness, clean away heat and expelling wind, expelling the wind and scatter the cold, clean away heat and expelling the wetness, heat up the meridian and scatter the cold, clean away heat and remove the toxin and etc. were used the method of internal therapy of psoriasis. 6. Until Qing dynasty, wind expelling effective prescriptions like Bangpungtongsungsan, Sopungsan. Supungsunkisan and etc. were used and recently Yanghyelgeupungtang, Hwalhyelgeupungtang, Samultanggagam and etc. were used the internal therapy of psoriasis. 7. In the external therapy of psoriasis, Yuhonggo, Pungyugo, Sekryupiyeongo were used the plaster therapy and Folium Rerillae, Camphora, Fructus, Xanthii, Herba Spirodelae compound prescription were used the cleansing therapy, Okgisan, Chiunsan, Galmyogo, Hobunsan, Muisan, Madugo, Jeyugohengin were used the rubbing skin therapy. Rangdok Radix Aconiti, Bijeonilchoalkwang were used the attaching therapy, the extract of Rhizoma Et Radix Veratri was used the spreading pouder therapy. 8. In the acupuncture therapy of psoriasis, the Jelgol, chok Samni(S36), Kansa(P5), Haegye(S41), Wijung(B40) and etc. were used the acupuncture point, and the angle of helix incision threapy that disinfect and cut the angle of helix and plaster the Semen Glycine and Squama Manitis were used.

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Thermal Effluent through Extruded Side Channel

  • Yoon, Tae-Hoon;Yook, Woon-Soo;Yi, Young-Kon
    • Korean Journal of Hydrosciences
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    • v.6
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    • pp.67-79
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    • 1995
  • The reattachment of buoyant efflluent to a shore in a crossflow is investigated experimentally. The effluent is prodeced by discharging heated water through a projected side channel into a confined crossflow of the same depth. In the projecting effluent, the size of recirculating region, which is formed by deflected thermal plume on the lee of the effluent, tends to increase, but the maximum temperature decreases in the direction of the crossflow and it has more uniform transverse spreading compared to non-projected type. The heat flux across the crossflow is found to be independent of the projceted length of the side channel under relatively high buoyancy flux on the contrary to low buoyancy flux. The reattachment of th effluent can be specified by both velocity ratio and densimetric Froude number, whereas only the velocity ratio is governing factor to the reattachment of the effluent in the case of non-projecting type.

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Examined of reinforcement for the fire protection of the outside insulation Urbantype Housing with flammable insulation material (가연성 단열재를 사용한 외단열 도시형 생활주택의 방화를 위한 보강재 검토)

  • Lee, Kwang-Hee;Jung, Ui-In;Kim, Bong-Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.11a
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    • pp.28-29
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    • 2015
  • Due to the big fire in Uijeongbu, the status of construction, fireproof materials and structural method were examined to prevent fire propagation through outside insulation parts of urban living homes. Through research and experiments, the following results were obtained. It was confirmed that outside heat-insulation wall method was used in a large number of urban living homes which were made of materials and structures spreading fire easily.Through experiments, it was revealed that lightweight plate material, as a fireproof material, can save the cost as well as the period of construction and obtain more than 30 minutes of evacuation time which is twice the maximum evacuation time.

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Ultrashort pulse laser induced PI film scribing (극초단파 레이저를 이용한 PI 필름 가공 기술개발)

  • Kim, Tae-Dong;Lee, Ho
    • Journal of the Korean Society of Industry Convergence
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    • v.20 no.4
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    • pp.307-311
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    • 2017
  • Ultra short pulse laser processing with the PI (polyimide) substrate is conducted to increase flexibility and radius of curvatures. A femtosecond laser is used to perform micro machining by minimizing the heat effect in PI substrate. The laser processing according to the parameters, such as fabricated line width, depth, laser power, distance between lines, is carried out to understand the characteristics of fabricated lines. A bending test is carried out to evaluate bending shapes and the radius of curvature after bending and spreading it 1000 times. The results demonstrates that the radius of curvature decreases in deepen lines and increases with the augment of the number of the fabricated lines, and distance between lines.

A Study on the impact and solidification of the liquid metal droplet in the thermal spray deposition (용사 공정에서 용융 금속 액적의 충돌현상과 응고 과정 해석)

  • Ha, Eung-Ji;Kim, Woo-Seung
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.214-219
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    • 2001
  • In this study, numerical investigation has been performed on the spreading and solidification of a droplet impacting onto a solid substrate in the thermal spray process. The finite difference method with volume-of-fluid approach is used to analyze the free surface flow and the source-based enthalpy method is employed to model the latent heat release during the solidification. In this work, the numerical model is validated through the comparison of the present numerical result with experimental data available for the flat substrate.

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Research of Foresight Knowledge by CMAC based Q-learning in Inhomogeneous Multi-Agent System

  • Hoshino, Yukinobu;Sakakura, Akira;Kamei, Katsuari
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.280-283
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    • 2003
  • A purpose of our research is an acquisition of cooperative behaviors in inhomogeneous multi-agent system. In this research, we used the fire panic problem as an experiment environment. In Fire panic problem a fire exists in the environment, and follows in each steps of agent's behavior, and this fire spreads within the constant law. The purpose of the agent is to reach the goal established without touching the fire, which exists in the environment. The fire heat up by a few steps, which exists in the environment. The fire has unsureness to the agent. The agent has to avoid a fire, which is spreading in environment. The acquisition of the behavior to reach it to the goal is required. In this paper, we observe how agents escape from the fire cooperating with other agents. For this problem, we propose a unique CMAC based Q-learning system for inhomogeneous multi-agent system.

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Ignition properties in simulator of 120mm tank charges (120mm 전차탄용 모사 장치에서의 점화 특성)

  • 이정환;권순길;황준식;김동섭;김태인;김진호
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.43-46
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    • 2003
  • This study was conducted via diagnostics in a transparent 120mm tank gun chamber simulator. Pressure rises at the breech and forward ends of the simulator chamber were measured by using PCB pressure gages. This technique has been used to develope of various advanced HEAT and KE rounds of 120mm tank gun. In the studies, many ignition phenomena occurring during the early phase of the ballistic cycle was observed and analyzed. It can provide insights into the functioning of the igniter, flame spreading, and formation of pressure waves in the gun chamber.

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