• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.57-58
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• 2008

PTC thermistor are characterized by an increase in the electrical resistance with temperature. The PTC materials of middle Curie point were produced or that of high Curie point (above $200^{\circ}C$), it was determined that compositional modifications of $Pb^{2+}$ for $Ba^{2+}$ produce change sin the Curie point to higher temperature. PTC ceramic materials with the Curie point above $120^{\circ}C$ were prepared by adding $PbTiO_3$, PbO or $Pb_3O_4$ into $BaTiO_3$. Thereby, adding $Pb^{2+}$ into $BaTiO_3$-based PTC material to improve Tc was studied broadly, however, weal know that PbO was poisonous and prone to volatilize, then to pollute the circumstance and hurt to people, so we should dope other innocuous additives instead of lead to increase Tc of composite PTC material. In order to prepare lead-free $BaTiO_3$-based PTC with middle Curie point, the incorporation on $Bi_{1/2}Na_{1/2}TiO_3$ into $BaTiO_3$-based ceramics was investigated on samples containing 0, 1, 2, 3, 4, and 50mol% of $Bi_{1/2}Na_{1/2}TiO_3$. $Bi_{1/2}Na_{1/2}TiO_3$ was compounded as standby material by conventional solid-state reaction technique. The starting materials were $Bi_{1/2}Na_{1/2}TiO_3$, $BaCO_3$, $TiO_2$ and $Y_2O_3$ powder, and using solid-state reaction method, too. The microstructures of samples were investigated by SEM, DSC, XRD and dielectric properties. Phase composition and lattice parameters were investigated by X-ray diffraction.

• 대한기계학회논문집B
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• 제40권2호
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• pp.85-91
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• 2016

내연기관 자동차와 달리 전기자동차는 배터리 폐열이 부족하여 실내 난방을 위해 추가적으로 PTC 히터를 사용하고 있지만 전력소모가 큰 단점이 있다. 최근 이러한 단점을 보완할 수 있는 히트펌프 적용에 관한 연구가 활발히 진행되고 있다. 본 연구에서는 히트펌프의 운전특성 해석을 위해 MATLAB/SIMULINK$^{(R)}$환경에서 R134a 히트펌프 모델과 캐빈 모델을 개발하였다. 모델은 여름과 겨울에서 히트펌프의 작동 특성에 따른 실내 온도변화를 나타낼 수 있으며, 모델 검증은 구성품 수준에서 응축기와 증발기의 용량 비교를 수행하였다. 또한 동일한 냉방조건에서 캐빈온도 변화 비교를 통해 캐빈 모델을 검증하였다. 해석 결과 전동압축기 소비전력은 모든 외기온도 조건에서 PTC 히터 보다 낮은 것으로 나타났다. 또한 영하조건에서 히트펌프의 난방용량이 부족한 현상에 대해 폐열회수를 적용하여 효율적인 난방 작동을 할 수 있는 조건을 분석하였다.

• 한국자동차공학회논문집
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• 제22권2호
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• pp.17-22
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• 2014

Recently, the quick heating performance is an important issue in the car because engine power becomes so high. So car makers have been adapted the additional heating devices as like PTC(Positive Temperature Coefficient) heater. And the quick cooling performance is also important issue because its result is used in the IQS(Initial Quality Study). In this paper, control of the HVAC(Heating, Ventilation and Air Conditioning) intake door has been studied for the quick heating and cooling performance. Heating performance is improved $4.0^{\circ}C$ at $-20^{\circ}C$ ambient temperature after 20 minutes. And cooling performance is improved $1.5^{\circ}C$ at $35^{\circ}C$ ambient temperature after 10 minutes. In addition, intake door control system brings on the cost reduction because the flab door can be eliminated. This intake door control system has been adapted to the new developing cars.

• Journal of Acupuncture Research
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• 제26권2호
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• pp.41-48
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• 2009

Objectives : The conventional direct and indirect moxibustion therapies for prostate treatment could not been applied to the acupuncture point of $CV_1$(Conception Vessel Meridian 1, 會陰) because of its boring body region. The position of $CV_1$(會陰) is the back side of hard part between the anus and the genital organ. The conventional moxibustion methods have many troubles in operating to the acupuncture point of $CV_1$(會陰). In order to get rid of these problems, we have suggested the special heat generating terminal especially for prostate. The features of the special heat generating terminal for prostate are the low temperature infrared heater and the adhesive moxa-pad. These features are no burnt, no fiery and especially suitable for the point of $CV_1$(會陰). Methods: The heat generating terminal which is a part of the moxa-extract moxibustion cauterizer is composed of a PTC(Positive Temperature Coefficients) ceramic heater and the adhesive moxa-pad We had got the experimental demonstrations by the stimulating the acupuncture points which are $CV_1$(會陰), $BL_{28}$(Bladder Meridian 28, 膀胱兪), and $CV_3$(Conception Vessel Meridian 3, 中極) with the special heat generating terminal for the prostatitis and the benign prosthetic hypertrophy. And the stimulation level was 43$^{\circ}C$ infrared heat for one hour. The type of thermography is IRIS-5000. Results : With one subject suffering the prostatitis and another subject suffering the benign prosthetic hypertrophy, we cauterized the acupuncture points $CV_1$(會陰), $BL_{28}$(膀胱兪) and $CV_3$(中極) with the special heat generating terminal for prostate. We measured the temperature variations by the thermography before and after stimulations. Finally we estimated the tendency of temperature decreasing in the region of post-stroke urinary symptoms and the improvement of nocturnal enuresis after the stimulations. Conclusions : We suggest that the special heat generating terminal of moxa-extract moxibustion cauterizer proposed herein is effective for the treatment of prostate by NIH-CPSI and IPSS.

• 한국재료학회지
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• 제20권12호
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• pp.654-660
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• 2010

The influences of Na and K content on the crystal phase, the microstructure and the electrical property of $BaTiO_3$-based thermistors was found to show typical PTC effects. The crystal phase of powder calcined at $1000^{\circ}C$ for 4hrs showed a single phase with $BaTiO_3$, and the crystal structure was transformed from tetragonal to cubic phase according to added amounts of Na and K. In XRD results at $43^{\circ}\sim47^{\circ}$, the $(Ba_{0.858}Na_{0.071}K_{0.071})(Ti_{0.9985}Nb_{0.0015})O_{3-\delta}$ showed (002) and (200) peaks but the $(Ba_{0.762}Na_{0.119}K_{0.119})(Ti_{0.9975}Nb_{0.0025})O_{3-\delta}$ showed (002), (020) and (200) peaks. In sintered bodies, those calcined at $600^{\circ}C$ rather than at $1000^{\circ}C$ were dense, and for certain amounts of Na and K showed rapid decreases in grain size. In relative permittivity, the curie temperature due to the transformation of ferroelectric phase rose with added Na and K but decreased in terms of relative permittivity. In the result of the R-T curve, the sintered bodies have curie temperatures of about $140^{\circ}C$ and the resistivity of sintered bodies have scores of $\Omega{\cdot}cm$; the jump order of sintered bodies was shown to be more than $10^4$ in powder calcined at $1000^{\circ}C$.

• Journal of Acupuncture Research
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• 제23권4호
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• pp.1-14
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• 2006

Objectives : We implemented the Moxa-Extract Moxibustion Method in order to improve the conventional moxibustion therapy. This method is aimed to eliminate burning wounds and smoke, which are the defects of conventional moxibustion therapy. And we performed to verify the efficiency by comparing the Moxa-Extract Moxibustion Method with the conventional Indirect Moxibustion Method. We measured the body heat and the lasting time of blood circulation improveent using thermography. We implemented the Moxa-Extract Moxibustion Method in order to improve the conventional moxibustion therapy. This method is aimed to eliminate burning wounds and smoke, which are the defects of conventional moxibustion therapy. And we performed to verify the efficiency by comparing the Moxa-Extract Moxibustion Method with the conventional Indirect Moxibustion Method. We measured the body heat and the lasting time of blood circulation improvement using thermography. Methods : The moxibustion therapy has two kinds of effects: The formers are pharmacological effects of the Moxa's vasodilators and antioxidants. The latters are thermal effects which cause improvement of the blood circulation. To remove the demerits without omission of above therapeutic effects, we extracted the vasodilators and antioxidant compounds from the Moxa-CH2Cl2 fraction Moxa-EtOA and composed the moxibustion kit with (Ba0.8 Sr0.2)0.996 Y0.004 TiO2 + 0.5WT SiO2% positive Temperature Coefficients Thermistor. The experimental demonstrations have been made by the stimulating the spot which is CV4(Kwan-Won), CV8(Shin-Guel), CV12(Jung-Wan) acupuncture points of the conception vessel meridian(CV). And stimulating time was one hour. We divided the subjects into 5 groups such as no stimulation group, conventional Indirect Moxibustion group, only Moxa-Extract stimulation group, only heat stimulation group, and Moxa-Extract Moxibustion group. In the different cases, we have measured the body heat in pre-stimulation, just after stimulation, 2 hours after, and 4 hours after. Results : he body heats of the group who were stimulated by the Moxa-Extract Moxibustion method were increased by over the $2^{\circ}C$. And the body heats of the group who were stimulated by the Indirect Moxibustion Method were increased by average the $1^{\circ}C$. We have evaluated that the Moxa-Extract Moxibustion Method is improvement on the Indirect Moxibustion Method by the increasing rate is 200% and increasing time is 150% with the body heat of the abdominal region. Conclusion : We have implemented the Moxa-Extract Moxibustion Method and evaluated the efficiency of the Moxa-Extract Moxibustion Method comparing with the Indirect Moxibustion Method.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권8호
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• pp.386-396
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• 2006

We implemented the Drug-Pad Moxibustion Method in order to improve the conventional moxibustion therapy. This method is aimed to eliminate burning wounds and smoke, which are the defects of conventional moxibustion therapy. And we performed to verify the efficiency by comparing the Drug-Pad Moxibustion Method with the conventional Indirect Moxibustion Therapy. We measured the body heat and the lasting time of blood circulation improvement using thermography. The moxibustion therapy has two kinds of effects: The formers are pharmacological effects of the Moxa's vasodilators and antioxidants. The latters are thermal effects which cause improvement of the blood circulation. To remove the demerits without omission of above therapeutic effects, we extracted the vasodilators and antioxidant compounds from the Moxa-$CH_2Cl_2$ fraction Moxa-EtOAc and composed the moxibustion kit with $(Ba_{0.8}\;Sr_{0.2})_{0.996}\;Y_{0.004}\;TiO_2+0.5_{WT}\;SiO_2%$ Positive Temperature Coefficients Thermistor. The experimental demonstrations have been made by the stimulating the spot which is CV4(Kwan-Won), CV8(Shin-Guel), CV12(Jung-Wan) acupuncture points of the conception vessel meridian(CV). And stimulating time was one hour. We divided the subjects into 5 groups such as no stimulation group, conventional Indirect Moxibustion group, only Drug-Pad stimulation group, only heat stimulation group, and Drug-Pad Moxibustion group. In the different cases, we have measured the body heat in pre-stimulation, just after stimulation, 2 hours after, and 4 hours after. The body heats of the group who were stimulated by the Drug-Pad Moxibustion Method were increased by over the $2^{\circ}C$. And the body heats of the group who were stimulated by the Indirect Moxibustion Method were increased by average the $1^{\circ}C$. We have evaluated that the Drug-Pad Moxibustion Method is improvement on the conventional Indirect Moxibustion Method by the heat-increasing rate is 200% and the lasting time is 150% with the body heat of the abdominal region. In the conclusions, We have implemented the Drug-Pad Moxibustion Method and evaluated the efficiency of the Drug-Pad Moxibustion Method comparing with the conventional Indirect Moxibustion Method.

• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.35-40
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• 2009

Lead free positive temperature coefficient of resistivity (PTCR) ceramics based on $BaTiO_3-(Bi_{0.5}Na_{0.5})TiO_3$ solid solution were prepared by a conventional solid state reaction method. The phase structure was showed single phase with perovskite structure regardless calcinations temperature and $Ba_{1-x}(Bi_{0.5}Na_{0.5})_xTiO_3$ structure was transformed from tetragonal to orthorhombic phase at $x{\geq}0.15$ mole. The XRD peaks with $45^{\circ}{\sim}46^{\circ}$ shifted in right the influence of crystal structure change and the intensity of peak was decreased with additive $(Bi_{0.5}Na_{0.5})TiO_3$. The curie temperature risen with additive $(Bi_{0.5}Na_{0.5})TiO_3$ but disappeared for $(Bi_{0.5}Na_{0.5})TiO_3$ addition more than 0.15 mole in TMA. In relative permittivity, the curie temperature by the transform of ferroelectric phase risen with additive $(Bi_{0.5}Na_{0.5})TiO_3$ but decreased in relative permittivity. Also, the peak of new curie temperature showed the sample containing $0.025{\sim}0.045$ mole of $(Bi_{0.5}Na_{0.5})TiO_3$ near $70^{\circ}C$ caused by phase transform from ferroelectric to ferroelectric and the peak of new curie temperature disappeared at 0.045 mole of $(Bi_{0.5}Na_{0.5})TiO_3$. In our study, it was found that the PTCR in $BaTiO_3-(Bi_{0.5}Na_{0.5})TiO_3$ system was possible for $0{\sim}0.025$ mole of $(Bi_{0.5}Na_{0.5})TiO_3$ and the maximum curie temperature by phase transition showed about at $145^{\circ}C$.