• Title, Summary, Keyword: phase change material

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A Study on Thermo-Physical Properties of Microencapsulated Phase Change Material Slurry (마이크로캡슐 잠열 축열재 혼합수의 열물성에 관한 연구)

  • 임재근;최순열;김명준
    • Journal of the Korean Society of Marine Engineering
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    • v.28 no.6
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    • pp.962-971
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    • 2004
  • This paper has dealt with thermo-physical properties of microencapsulated phase change material slurry as a latent heat storage material having a low melting point. The measured results of the thermo-physical properties of the test microencapsulated phase change material slurry, those are, density, specific heat, thermal conductivity and viscosity, were discussed for the temperature region of solid and liquid phases of the dispersion material (paraffin). The measurements of these properties of microencapsulated phase change material slurry have been carried out by using a specific-gravity meter, a water calorimeter, a differential scanning calorimeter(DSC), a transient hot wire method and rotating type viscometer, respectively. It was clarified that the additional properties law could be applied to the estimation of the density and specific heat of microencapsulated phase change material slurry and also the Euckens equation could be applied to the estimation of the thermal conductivity of this slurry.

Scaling Down Characteristics of Vertical Channel Phase Change Random Access Memory (VPCRAM)

  • Park, Chun Woong;Park, Chongdae;Choi, Woo Young;Seo, Dongsun;Jeong, Cherlhyun;Cho, Il Hwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.1
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    • pp.48-52
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    • 2014
  • In this paper, scaling down characteristics of vertical channel phase random access memory are investigated with device simulator and finite element analysis simulator. Electrical properties of select transistor are obtained by device simulator and those of phase change material are obtained by finite element analysis simulator. From the fusion of both data, scaling properties of vertical channel phase change random access memory (VPCRAM) are considered with ITRS roadmap. Simulation of set reset current are carried out to analyze the feasibility of scaling down and compared with values in ITRS roadmap. Simulation results show that width and length ratio of the phase change material (PCM) is key parameter of scaling down in VPCRAM. Thermal simulation results provide the design guideline of VPCRAM. Optimization of phase change material in VPCRAM can be achieved by oxide sidewall process optimization.

The study about phase phase change material at nano-scale using c-AFM method (c-AFM 기술을 이용한 나노급 상변화 소자 특성 평가에 대한 연구)

  • Hong, Sung-Hoon;Lee, Heon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.57-57
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    • 2010
  • In this study, nano-sized phase change materials were evaluated using nanoimprint lithography and c-AFM technique. The 200nm in diameter phase change nano-pillar device of GeSbTe, AgInSbTe, InSe, GeTe, GeSb were successfully fabricated using nanoimprint lithography. And the electrical properties of the phase change nano-pillar device were evaluated using c-AFM with pulse generator and voltage source.

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Electrical and thermal characteristics of PRAM with thickness of phase change thin film (상변화 박막의 두께에 따른 상변화 메모리의 전류 및 열 특성)

  • Choi, Hong-Kyw;Kim, Hong-Seung;Lee, Seong-Hwan;Jang, Nak-Won
    • Journal of the Korean Society of Marine Engineering
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    • v.32 no.1
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    • pp.162-168
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    • 2008
  • In this paper, we analyzed the heat transfer phenomenon and the reset current variation of PRAM device with thickness of phase change material using the 3-D finite element analysis tool. From the simulation, Joule's heat was generated at the contact surface of phase change material and bottom electrode of PRAM. As the thickness of phase change material was decreased, the reset current was highly increased. In case thickness of phase change material thin film was $200\;{\AA}$, heat increased through top electrode and reset current caused by phase transition highly increased. And as thermal conductivity of top electrode decreased, temperature of unit memory cell was increased.

Effect of GaGe Sputtering Power on Ga Doping in Phase Change Memory Materials (상 변화 메모리 재료 내의 Ga 주입에 미치는 GaGe 스퍼터링 전력의 영향)

  • Jung, Soon-Won;Lee, Seung-Yun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.5
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    • pp.285-290
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    • 2015
  • The phase change memory material is an active element in phase change memory and exhibits reversible phase transition behavior by thermal energy input. The doping of the phase change memory material with Ga leads to the increase of its crystallization temperature and the improvement of its amorphous stability. In this study, we investigated the effect of GaGe sputtering power on the formation of the phase change memory material including Ga. The deposition rate linearly increased to a maximum of 127 nm and the surface roughness remained uniform as the GaGe sputtering power increased in the range from 0 to 75 W. The Ga concentration in the thin film material abruptly increased at the critical sputtering power of 60 W. This influence of GaGe sputtering power was confirmed to result from a combined sputtering-evaporation process of Ga occurring due to the low melting point of Ga ($29.77^{\circ}C$).

Thermal characteristic of PRAM with top electrode (상부전극에 따른 상변화 메모리의 발열 특성)

  • Choi, Hong-Kyw;Jang, Nak-Won;Kim, Hong-Seung;Lee, Seong-Hwan;Mah, Suk-Bum
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.97-98
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    • 2007
  • In this paper, we analyzed the reset current variation of PRAM device with top electrode using the 3-D finite element analysis tool. As thickness of phase change material thin film decreased, reset current caused by phase transition highly increased. Joule's heat which was generated at the contact surface of phase change material and bottom electrode of PRAM was given off through top electrode to which was transferred phase change material. As thermal conductivity of top electrode decreased, heating temperate was increased.

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Electromagnetic and Thermal Analysis of PRAM cell with phase change material (상변화 재료의 물질상수에 따른 PRAM cell의 전자장 및 열 해석)

  • Jang, Nak-Won;Kim, Hong-Seung;Lee, Seong-Hwan;Mah, Suk-Bum
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.144-145
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    • 2007
  • Phase change random access memory is one of the most promising candidates for next generation non-volatile memories. However, the high reset current is one major obstacle to develop a high density PRAM. One way of the reset current reduction is to develop the new phase change material. In this paper, to reduce the reset current for phase transition, we have investigated the effect of phase change material parameters using finite element analysis.

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Preparation of Polyurea Microcapsules Containing Phase Change Material and their Application on Fiber Composites (상전이물질을 함유한 폴리우레아 마이크로캡슐의 제조와 섬유복합소재에의 적용)

  • Kim, Hea-In;Jin, Xuan-Zhen;Choi, Hae-Wook;Park, Soo-Min
    • Textile Coloration and Finishing
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    • v.19 no.1
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    • pp.37-44
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    • 2007
  • In this study, for textile use, the octadecane of phase change materials(PCM) was encapsulated in several micro-diameter shell which prevents leakage of the material during its liquid phase. Microencapsulated PCM(PM) was prepared with the different weight ratio of core material to wall material and by interfacial polymerization methods using polyurea as shell material. Phase stability for O/W emulsion of PCM and PVA aq. (PE) was evaluated by Turbiscan Lab. The capsule formation win identified using FT-IR. Physical properties of microcapsules including diameter, particle distribution, morphology were investigated. Thermal transport properties of suede treated with PM(SPM) were determined by KES-F7 system.

Design of a Plasmonic Switch Using Ultrathin Chalcogenide Phase-change Material

  • Lee, Seung-Yeol
    • Current Optics and Photonics
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    • v.1 no.3
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    • pp.239-246
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    • 2017
  • A compact plasmonic switching scheme, based on the phase change of a thin-film chalcogenide material ($Ge_2Sb_2Te_5$), is proposed and numerically investigated at optical-communication wavelengths. Surface plasmon polariton modal analysis is conducted for various thicknesses of dielectric and phase-change material layers, and the optimized condition is induced by finding the region of interest that shows a high extinction ratio of surface plasmon polariton modes before and after the phase transition. Full electromagnetic simulations show that multiple reflections inside the active region may conditionally increase the overall efficiency of the on/off ratio at a specific length of the active region. However, it is shown that the optimized geometrical condition, which shows generally large on/off ratio for any length of active region, can be distinguished by observing the multiple-reflection characteristic inside the active region. The proposed scheme shows an on/off switching ratio greater than 30 dB for a length of a few micrometers, which can be potentially applied to integrated active plasmonic systems.

Inhibitory Effect of adding Phase Change Material (PCM) to Fire Fighter Protective Clothing on Burn Injuries (Phase Change Material (PCM) 소재 적용 소방보호복의 화상발생 억제효과에 관한 연구)

  • Lee, Jun Kyoung
    • Fire Science and Engineering
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    • v.30 no.3
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    • pp.16-22
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    • 2016
  • Fire fighters rely on fire fighter protective clothing (FFPC) to provide adequate protection in the various hazardous environments. To enhance its protection performance, the FFPC material must be thick and thus it is difficult to achieve weight reduction. One of the methods of overcoming this problem, the addition of phase change material (PCM) to FFPC, is a new technology. In previous studies, the researches was mostly related to the temperature characteristics of the fibers incorporating PCM, but little information is available about its effect on burn injuries. Thus, in this study, the inhibitory effects of adding PCM to FFPC on second degree burns were investigated through numerical calculations. Thermal analyses of biological tissues and FFPC with embedded PCM exposed to several fire conditions causing severe tissue damage were studied by using a finite difference method based on the Pennes bio-heat equation. FFPC with embedded PCM was found to provide significantly greater protection than conventional fire fighting clothing, because the heat of absorption due to the phase change within the material is used to limit the heat conduction of the material.