• Fibers and Polymers
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• 제2권2호
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• pp.81-85
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• 2001

The effects of rate of phase separation to ester interchange reactions and the repulsive pair interaction energy on the phase behavior in a phase-separated immiscible polyester blend are investigated using a Monte Carlo simulation method. The time evolution of structure factor and the degree of randomness are monitored as a function of homogenization time. When the phase separation is dominant over ester interchange reactions, the domain size slowly increases with homogenization time. However, when the pair interaction becomes less repulsive, the domain size does not significantly change with homogenization time. On the other hand, when ester interchange reactions are dominant over the phase separation, the homogenization proceeds without a change in the domain size. The higher the extent of phase separation, the lower the increasing rate of the DR. However, when the phase separation is sufficiently dominant, the effect of the extent of phase separation on the increasing rate of the degree of randomness become less significant.

• Steel and Composite Structures
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• 제36권5호
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• pp.521-531
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• 2020

The behavior variation of concrete dam is investigated, based on a new method for analyzing the data model of concrete dam in service process for the limitation of wavelet transform for solving concrete dam service process model. The study takes into account the time and position of behavior change during the process of concrete dam service. There is no dependence on the effect quantity for overcoming the shortcomings of the traditional identification method. The panel data model is firstly proposed for analyzing the behavior change of composite concrete dam. The change-point theory is used to identify whether the behavior of concrete dams changes during service. The phase space reconstruction technique is used to reconstruct the phase plane of the trend effect component. The time dimension method is used to solve the construction of multi-transformation model of composite panel data. An existing 76.3-m-high dam is used to investigate some key issues on the behavior change. Emphasis is placed on conversion time and location for three time periods consistent with the practical analysis report for evaluating the validity of the analysis method of the behavior variation of concrete dams presented in this paper.

• 한국전기전자재료학회논문지
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• 제30권2호
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• pp.86-90
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• 2017

This work reports the phase-change behavior and thermal stability of doped GeSbTe/GeSbTe bilayers. We prepared the bilayers using RF sputtering, and annealed them at annealing temperature ranging from $100^{\circ}C$ to $400^{\circ}C$. The sheet resistance of the bilayer decreased and saturated with increasing annealing temperature, and the saturated value was close to that of pure GeSbTe film. The surface of the bilayer roughened at $400^{\circ}C$, which corresponds to the surface roughening of doped GeSbTe film. Mixed phases of face-centered cubic and hexagonal close-packed crystalline structures were identified in the bilayers annealed at elevated temperature. These results indicate that the phase-change behavior of the bilayer depends on the concurrent phase-transitions of the two GeSbTe-based films. The dopants in the doped GeSbTe film were diffused out at annealing temperatures of $300^{\circ}C$ or higher, which implies that the thermal stability of the bilayer should be considered for its application in phase-change electronic devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.657-657
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• 2013

In-situ observations of nano-scale behavior of nanomaterials are very important to understand onthe nano-scale phenomena associated with phase change, atomic movement, electrical or optical properties, and even reactions which take place in gas or liquid phases. We have developed on the in-situ experimental technologies of nano-materials (nano-cluster, nanowire, carbon nanotube, and graphene, et al.) and their interactions (percolation of metal nanoclusters, inter-diffusion, metal contacts and phase changes in nanowire devices, formation of solid nano-pores, melting behavior of isolated nano-metal in a nano-cup, et al.) by nano-discovery membrane platform [1-4]. Between two microelectrodes on a silicon nitride membrane platform, electrical percolations of metal nano-clusters are observed with nano-structures of deposited clusters. Their in-situ monitoring can make percolation devices of different conductance, nanoclusters based memory devices, and surface plasmonic enhancement devices, et al. As basic evidence on the phase change memory, phase change behaviors of nanowire devices are observed at a nano-scale.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.53-56
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• 2003

The objective of this research is to investigate the thermal behavior of microencapsulated phase-change materials(MEPCM), and a shell of melamine-formaldehyde. These PCM materials were tested using DSC and thermal data station. Fabrics with enhanced thermal properties were prepared by padding the fabrics with the microcapsules containing PCM and acryl binder. The rate of temperature increase was significantly decreased as the amount of MEPCM added on the surface of the fabrics increased.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.187-198
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• 1996

In this study, the performance of an automobile heat storage system using PCM is numerically simulated. For the analysis of system performance. The phase-change of the PCM and the transient forced convective heat transfer for the HTF are considered simultaneously as a conjugate problem. The phase-change behavior is effectively analyzed using a concept of thermal resistance. From the correlations of phase change rate and heat transfer due to the variations of flow rate of HTF around PCM, the automobile heat storage system performance is predicted. The present results amy be used as the fundamental information for the design of automobile heat storage system.

• 한국자기학회지
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• 제8권4호
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• pp.179-184
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• 1998

일반적으로 페로브로스카이트 구조의 망간 산화물에서 많이 관찰되어온 초거대 자기 저항 현상은 임계점 (큐리온도) 부근에서 온도 변화에 의한 상자성-강자성 상전이와 동반한 전기 전도 기수 변화에 따른 급격한 저항 변화와 매우 밀접한 광계가 있다. 본 논문에서는 이러한 전기 저항-온도 거동을 모사하기 위해, 온도에 따른 상분율 변화 함수를 유효매질 이론(effective media theory)을 이용하여 모형식을 마련하엿다. 미 모형식은 실제 La0.7Ca0.3MnO3의 저항-온도 거동을 매우 정확하게 모사하였다.

• 대한금속재료학회지
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• 제47권6호
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• pp.372-377
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• 2009

We report on hysteresis behavior in the electrical resistance-hydrogen concentration of Pd thin films. The variation of the electrical resistance has been investigated during the process of absorption and desorption of hydrogen gas ($H_{2}$) as a function of thickness of Pd thin films. The hysteresis behavior in the electrical resistance with $H_{2}$ concentration was found for Pd thin films and consists of $\alpha$ phase, ${\alpha}+{\beta}$ phase, and $\beta$ phase regions. The sensitivity of Pd thin films with $H_{2}$ concentration was found to follow Sieverts' law in the $\alpha$ phase region. However, the sensitivity was observed to increase abruptly with $H_{2}$ concentration in the ${\alpha}+{\beta}$ phase co-exist region. This is because Pd-H interaction is stronger in the $\beta$ phase than in the $\alpha$ phase and needs a higher concentration gradient as a driving force to desorb. The formation of the $\beta$ phase also was observed to cause the structural change because of the lattice expansion during absorption. The hysteresis height and the trace of structural change were affected by the thickness of the Pd film. As the film becomes thinner, the hysteresis height becomes lower and the amount of delamination on the surface becomes smaller. For films thinner than 20 nm in thickness, the delamination was not found but electrical resistance hysteresis was still observed.

• The Korean Journal of Pain
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• 제27권2호
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• pp.118-124
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• 2014

Background: The chronic pain can disturb physical, psychological, and social performances. Analgesic agents are widely used but some antidepressants (ADs) showed analgesia also. Bupropion is using for smoke cessation but it can change morphine withdrawal signs such as pain. This study tested the acute systemic effect of bupropion on formalin induced pain behavior in rats. Methods: Wistar male healthy rats were divided into 7 groups (control, sham, and 5 treated groups with 10, 30, 90, 120, and 200 mg/kg of bupropion, i.p.). The bupropion injected 3 hours prior to formalin induced pain behavior. Formalin (50 ${\mu}l$, 2.5%) was injected subcutaneously in dorsal region of right hindpaw in all animals. Nociceptive signs were observed continuously on-line and off-line each minute. Common pain scoring was used for pain assessment. Results: The analysis of data by one-way ANOVA showed that bupropion can reduce pain scores in the second phase but not in first phase. Bupropion decreased the licking/biting duration significantly in first and second phase of formalin test. Conclusions: The results showed that bupropion has analgesic effects at systemic application. The change of second phase of the pain behavior was significant and it revealed that central mechanisms involve in bupropion analgesia.

• 농약과학회지
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• 제12권4호
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• pp.397-402
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• 2008

Emamectin benzoate와 pyridaben에 대한 담배가루이의 잔효성과 섭식행동의 상관관계를 조사하였다. EPG의 파형은 non-probe time과 phloem phase time과 같은 파형을 신호개시 후 3시간 동안 기록하여 분석하였다. EPG 파형 중 non-probe time과 phloem phase time의 두 파형과 emamectin benzoate와 Pyridaben의 두 약제 간 잔효성의 상관관계 분석에서 모두 상관관계가 있는 것으로 나타났다. 잔효성은 두 약제 모두 2일까지는 50%로 비슷하였으나, 그 이후로는 pyridaben보다 emamectin benzoate가 급격히 감소하였다. EPG를 이용한 두 약제의 잔효성에 따른 구침을 찌른 시간과 체관부 섭식행동은 9일 이후부터 증가하는 경향을 보였으며, emamectin benzoate가 pyridaben보다 증가하는 속도가 빨랐다.