• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.397-400
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• 2001

상변화물질(phase change material, PCM)은 외부온도변화에 따른 상변화에 따라 흡열과 방열성을 반복적으로 나타내는 물질로서 건축, 우주항공분야 등에서 열전달매체나 열조절시스템에 응용되어 왔다. 이러한 PCM의 응용방법은 PCM을 미세한 입자(직경이 약 100$\mu\textrm{m}$)로 만들어 직접 운반유체 속에 분산시켜 이용하거나, PCM을 심물질로 하는 마이크로캡슐을 제조하여 이용하는 방법을 들 수 있다. (중략)

• Journal of the Korean Ceramic Society
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• v.27 no.6
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• pp.735-740
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• 1990

The phase transformation of Y-TZP by low temperature aging treatments and its related behaviors of crack formation were investigated. The kinetics of phase transformation was greatly dependent on the amounts of Y2O3, grian size and microstructures of sintered body. The phase transformation happened to start at specimen surface and near the pore in the first place, where the change of strain energy during the phase transformation was small and the water vapor that accelerated phase transformation easily diffused.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.569-570
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• 2013

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.223-226
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• 2008

$Ge_1Se_1Te_2$ chalcogenide amorphous materials was prepared by the conventional melt-quenching method. Samples were processed bye-beam evaporator systems and RF-sputtering systems. Phase change characteristics were analyzed by measuring glassification temperature, crystallization temperature and density of bulk material. The thermal characteristics were measured at the temperature between 300 K and 700 K, and the electrical characteristics were studied within the range from 0 V to 3 V. The obtained results agree with the electrothermal model for Phase-Change Random Access Memory.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.188-193
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• 2005

To provide the various machining materials with excellent quality and dimensional accuracy, high -speed machining is very useful tool as one of the most effective rapid manufacturing processes. However, high-speed machining is not suitable for microscale thin-walled structures because of the lack of the structure stiffness to resist the cutting force. A new method which is able to make a very thin-walled structure rapidly will be proposed in this paper. This method is composed two processes, high-speed machining and filling process. Strong workholding force comes out of the solidification of filling materials. Low-melting point metal alloys are used in order to minimize the thermal effect during phase change and to hold arbitrary shape thin-walled structures quickly during high-speed machining. To verify the usefulness of this method, we will show some applications, for examples thin -wall cylinders and hemispherical shells, and compare the experimental results to analyze the dimensional accuracy of typical parts of the structures.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.707-712
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• 2005

PRAM (Phase change random access memory) is one of the most promising candidates for next generation Non-volatile Memories. The Phase change materials have been researched in the field of optical data storage media. Among the phase change materials. $Ge_2Sb_2Te_5$ is very well known for its high optical contrast in the state of amorphous and crystalline. However the characteristics required in solid state memory are quite different from optical ones. In this study. the structural Properties of GeSbTe thin films with composition were investigated for PRAM. The 100-nm thick $Ge_2Sb_2Te_5$ and $Sb_2Te_3$ films were deposited on $SiO_2/Si$ substrates by RF sputtering system. In order to characterize the crystal structure and morphology of these films. x-ray diffraction (XRD). atomic force microscopy (AFM), differential scanning calorimetry (DSC) and 4-point measurement analysis were performed. XRD and DSC analysis result of GST thin films indicated that the crystallization of $Se_2Sb_2Te_5$ films start at about $180^{\circ}C$ and $Sb_2Te_3$ films Start at about $125^{\circ}C$.

• Journal of the Semiconductor & Display Technology
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• v.8 no.1
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• pp.13-17
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• 2009

In PRAM applications, the devices can be made for both binary and multi-state storage. The ability to attain intermediate stages comes either from the fact that some chalcogenide materials can exist in configurations that range from completely amorphous to completely crystalline or from designing device structure such a way that mimics multiple phase chase phenomena in single cell. We have designed stack-structured phase change memory cell which operates as multi-state storage. Amorphous $Ge_xTe_{100-x}$ chalcogenide materials were stacked and a diffusion barrier was chosen for each stack layers. The device is operated by crystallizing each chalcogenide material as sequential manner from the bottom layer to the top layer. The amplitude of current pulse and the duration of pulse width was fixed and number of pulses were controlled to change overall resistance of the phase change memory cell. To optimize operational performance the thickness of each chalcogenide was controlled based on simulation results.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.14.2-14.2
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• 2007

• Proceedings of the Korea Crystallographic Association Conference
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• 2007.11a
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• pp.49-49
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• 2007

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.9
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• pp.477-483
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• 2013

A numerical analysis of solid-liquid phase change was performed on a heat transfer module which consisted of circulating water path (BRINE), heat transfer plate (HTP) and phase change material (PCM) layers, such as high temperature PCM (HPCM, $78{\sim}79^{\circ}C$) and low temperature PCM (LPCM, $28{\sim}29^{\circ}C$). There were five arrangements, consisting of BRINE, HTP, LPCM and HPCM layers in the heat transfer module. The time and heat transfer rate for melting/solidification was compared to their arrangements, against each other. As results, the numerical time without convection was longer than the experimental one for melting/solidification. Moreover, the melting/solidification with the BRINE I-LPCM-BRINE II-HPCM arrangement was faster(10 hours) than the others; HPCM-BRINE-LPCM, BRINE I-HPCM-LPCM-BRINE II one.