• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.666-671
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• 2014

Using positive temperature coefficient (PTC) heater as supplementary heating for diesel engine vehicles with low heat source is a good method to enhance the heating performance during cold start. In this study, the PTC elements were made by using screen printing process for forming ohmic contact layer, and prototype of PTC heater was designed and made for a diesel engine vehicle. In process of designing the PTC heater, the thermal flow analysis of PTC element modules was conducted for verifying the effect of the shapes of contact surface between each of the components (cooling fin, insulator, ceramic element). We also investigated the performance characteristic (heating capacity, energy efficiency, pressure drop) of the PTC heater through the experiments. Therefore, the experimental results indicated that prototype of PTC heater had satisfactory performance. This study will be basis for improving the manufacturing process and increasing the performance of the PTC element and heater.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.101-108
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• 2003

Polymeric positive temperature coefficient(PTC) composites have been prepared by incorporating carbon black(CB) into high density polyethylene(HDPE), polyphenylene sulfide(PPS) and polybutylene terephthalate(PBT) matrices. A PTC effect was observed in the composite, caused by the large thermal expansion due to He consecutive melting of HDPE, PPS and PBT crystallites. This theory is based upon the premise that the PTC phenomenon is due to a critical separation distance between carbon particles in the polymer matrix at the higher temperature. The influence of PTC characteristics of the PPS/CB composite can be explained by DSC result. HDPE, one of prepared composition, exhibit the higher performance PTC behavior that decreaseing of negative temperature coefficient(NTC) effect and improved reproducibility by chemically crosslinking. Also, PBT/CB and PPS/CB composites exhibit the higher PTC peack temperature than HDPE/CB PTC composite, individually $200^{\circ}C$ and $230^{\circ}C$. These PTC composite put to good use in a number of safety application, such as self$.$controlled heater, over-current protectors, auto resettable switch, high temperature proctection sensor, etc.

• Journal of the Korean Solar Energy Society
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• v.34 no.3
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• pp.49-56
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• 2014

A fiat-plate or vacuum tube solar collector have been mainly used for hot water supply of house because of some being difficult to get uniform energy density, so little applied into industrial field. This study is to apply the PTC(parabolic trough collector) solar collector into industrial field such as sludge dewatering system for energy reduction. The real scale system which composed of PTC Solar Collector and Thermal Dewatering (TDW) is established. PTC solar collector is designed to produce a hot water with $80^{\circ}C$ of temperature. And size of TDW is $630{\times}630mm$. Hot water produced from PTC solar collector is supplied into heating plate of TDW, and sludge like waterworks or wastewater is dewatered. PTC solar collector with $10m^2$ of area produce energy of average 5,618 kcal. As according to results from real scale performance, solar collector takes charge 94 % of the amount that TDW consume energy which is so large part if compare with boiler. It means that PTC solar collector is useful to apply industrial field under the condition of sufficient solar radiation. And it is analyzed that TDW by PTC solar collector has an economical validity.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.1
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• pp.63-72
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• 1998

후막 PTC를 제조하기 위하여 BaTiO3 주원료에 Sb2O3와 MnO2를 첨가한 PTC 페이 스트를 ZrO2와 BaTiO3 기판위에 인쇄한후 13$25^{\circ}C$에서 1시간 동안 소결하였다. BaTiO3 기판 위에 형성된 PTC후막은 PTCR 특성을 나타내었다. 그러나 ZrO2기판위에 인쇄된 시편의 경 우 PTCR특성이 나타나지 않았다. 이것은 ZrO2기판과 인쇄된 PTC페이스트간의 열팽창계수 차이에 의한 thermal cracking 때문에 후막 PTC 형성이 불가능함을 보여주었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.719-725
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• 2000

In order to save the energy and to protest environmental conservation, a evaporation type of PTC heater was developed as a Part of replacement in automobile industry. The honeycomb type of PTC heater made by Texas Instrument draw a much attention for this purpose. Especially this paper will describe the general and characterize the typical electrical properties of PTC heater for the application of automobile in detail.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.71-74
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• 2005

In this paper, the effects of the MWCNTs on the PTC characteristics of the conventional CB/polymer nanocomposites were investigated. For the uniform dispersion of the MWCNTs in the polymer matrix., nitricacid-treated MWCNTs were dispersed with the dissolved HOPE in the solvent. After evaporating solvent, the dried master batches in the oven were melt blended mixed with CB and HDPE to obtain the PTC materials. The initial resistivity of PTC materials decreased and the PTC intensity increased with the MWCNTs. During three repeated heating and cooling cycles, the PTC materials containing MWCNTs showed a great reproducibility due to the conductive network structures of CB particles and MWCNTs.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.1
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• pp.29-38
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• 2001

In this paper, the defrosting characteristics of a PTC heating sheet is investigated by means of a defrosting heat source for the fin-tube heat exchanger in a refrigerator The defrosting characteristics of the PTC heating sheet are examined and compared with those of a conventional electric heater experimentally. It is found that the characteristics of the water draining rate with the defrosting time show a smoothly oscillating pattern when the PTC heating sheet Is used, and the drained water is completely melted. The defrosting efficiency of the PTC heating sheet is found to be about 75%, which is about 25% higher than that of the electric heater. Also, the reduction of the defrosting time and the increment of the defrosting efficiency may be obtained by improving the arrangement of the heating elements of the healing sheet. It is shown that the defrosting time of the PTC heating sheet increases linearly with the amount of frost, whereas the defrosting efficiency is nearly constant. When applying the PTC heating sheet to the refrigerating system, one should notice the fact that the defrosting performance of the PTC heating sheet may be degraded due to the repetitive operations.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.18-20
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• 2005

일반적으로 저압계통의 고장전류를 차단하기 위해 설치된 차단기의 차단원리는 주로 역전압발생법올 이용하고 있다. 역전압발생법은 효과적으로 저압계통의 고장전류를 차단할 수 있으나, 제한된 한류성능과 긴 아킹 시간은 차단기는 물론 주변 전력기기에 전기적/열적/기계적 스트레스를 주게 된다. 국내외 업체는 고장전류를 보다 빠르고 효과적으로 제한 및 차단을 할 수 있는 한류형 차단기를 제안하고 있는 실정이다. 저압계통의 경우, 정온도계수 (Positive Temperature Coefficient, PTC) 특성을 가지는 한류소자를 기존 차단기에 직렬 혹은 병렬로 연결하여 저압계통의 고장전류를 매우 빠르고 효과적으로 제한 및 차단하는 추세에 있으며, 또한 PTC 한류소자를 이용함으로써 저압계통의 차단보호협조를 효과적으로 구현하고자 하고 있다. PTC 한류소자는 소자는 열팽창이 큰 비전도성 성분과 열팽창이 작은 전도성 성분이 혼합되어 구성되며, 소자의 온도가 증가함에 따라 비전도성 성분이 상대적으로 큰 부피 팽창을 하여 저항이 증가하게 된다. 이러한 PTC 소자를 전력계통에 적용함으로써 고장전류에 따른 줄열에 의한 저항증가로 고장전류를 제한하게 된다. 본 연구에서는 일반적으로 배터리 보호용으로 사용되는 폴리에틸렌 수지 및 카본블랙으로 구성된 폴리머 PTC 한류소자를 이용하여, 기존의 저전력 배터리 보호 폴리머 PTC 소자로부터, 저압계통의 단락사고시 발생하는 단락전류를 효과적으로 제한할 수 있는 대전력 폴리머 PTC 소자를 개발하였다.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2447-2451
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• 2015

Background: Human papillary thyroid carcinoma (PTC) is often associated with Hashimoto's thyroiditis (HT); their coexistence improves PTC prognosis. Osteopontin, a secreted glycoprotein, plays a role in cell survival, immunity, and tumor progression, its expression being associated with a poor prognosis and metastasis in several malignancies. Osteopontin overexpression correlates with aggressive clinicopathological features in PTC. Lymph node metastases and large tumor size positively correlate with osteopontin positivity. This study aimed to: (1) confirm osteopontin overexpression in human PTC samples; (2) compare osteopontin expression levels in PTC cases with and without HT; and (3) identify correlations between tumor aggressiveness and osteopontin expression levels. Materials and Methods: Plasma osteopontin was assessed in 45 patients with PTC, 22 patients with PTC and HT, and 24 healthy controls by enzyme-linked immunosorbent assay. Thyroid tissue osteopontin mRNA and protein levels were analyzed by reverse transcription-polymerase chain reaction and Western blotting, respectively. Results: Plasma osteopontin levels were significantly higher in PTC patients than in healthy controls. Plasma osteopontin, tissue osteopontin mRNA, and tissue osteopontin protein levels were significantly lower in patients with PTC and HT than in those with PTC alone. In advanced disease stage cases, osteopontin mRNA and protein expression levels were lower in patients with PTC and HT than in those with PTC alone. However, the osteopontin expression level was not significantly associated with the TNM stage. Conclusions: Plasma osteopontin, tissue osteopontin mRNA, and tissue osteopontin protein levels were significantly lower in patients with PTC and HT than in those with PTC alone, suggesting that HT attenuates PTC aggressiveness through negative regulation of osteopontin expression.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.31-35
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• 2006

This paper is studied on a protective control system for electrical fire used electrical characteristics of SCR and multilayer-type PTC thermistor. The PTC thermistor has characteristic or positive resistivity temperature coefficient according to the temperature variation, which is construction of a regular square and cube demarcation with $BaTiO_{3_}$Ceramics of positive temperature coefficient. Also PTC shows the phenomenon which is rapidly increased in the resistivity if the temperature is increased over Curie temperature point. This paper is proposed on a protective control system used multilayer-type PTC which is protected from electrical fire due to electric short circuit faults or overload faults. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.