• Proceedings of the Korean Magnestics Society Conference
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• 2011.12a
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• pp.155-155
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• 2011

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.77-77
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• 2006

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.610-615
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• 2002

Phase formation and proton conduction of L $a_{0.6}$B $a_{0.4}$I $n_{1-y}$ $M_{y}$ $O_{3-{\delta}}$(M=G $a^{3+}$, S $c^{3+}$, Y $b^{3+}$) system were studied. A cubic perovskite structure with a single phase was formed in all of the compositions of this work except for the composition off=G $a^{3+}$ with y=0.5, viz,L $a_{0.6}$B $a_{0.4}$I $n_{1-y}$G $a_{0.5}$ $O_{3-{\delta}}$ For the compositions of M=S $c^{3+}$and Y $b^{3+}$with y=0.25, proton conduction occurred in wet $N_2$ atmosphere(P $h_{H_2O}$=6.1hPa).X>/=6.1hPa).Pa).

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.9-10
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• 2014

최근 신재생에너지 및 전기자동차, 통신 IT 서버 전원 및 가전기기 등의 발전에 따라 고 전력밀도(High Power Density), 고 응답(Fast Transient Response) 및 고정밀(Tight Regulation) 출력제어를 위한 다 출력 절연형 DC/DC 컨버터가 개발 및 연구되고 있다. 본 논문에서는 개별적인 정밀제어를 요구하는 다 출력 DC-DC 컨버터에 대한 내용으로 위상천이(Phase-shift) DC-DC 컨버터와 LLC 공진컨버터 제어개념을 하나의 주회로를 사용하여 위상천이제어(Phase-shifted Modulation, PM)와 가변주파수제어(Variable Frequency Modulation, FM)를 통해서 개별적으로 정밀 제어할 수 있는 하이브리드 다 출력 3레벨 DC-DC 컨버터에 관한 내용이다.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.110-112
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• 1995

In this paper, We have designed the new Two-Double 1-2 phase exciting method. And We have developed the chopper constant current drive circuit in order to apply Two-Double 1-2 phase exciting method to 4-phase Stepping Motor.

• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.138-147
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• 2019

Purpose: Several studies have shown that the oral cavity is a secondary location for Helicobacter pylori colonization and that H. pylori is associated with the severity of periodontitis. This study investigated whether H. pylori had an effect on the periodontium. We established an invasion model of a standard strain of H. pylori in human periodontal ligament fibroblasts (hPDLFs), and evaluated the effects of H. pylori on cell proliferation and cell cycle progression. Methods: Different concentrations of H. pylori were used to infect hPDLFs, with 6 hours of co-culture. The multiplicity of infection in the low- and high-concentration groups was 10:1 and 100:1, respectively. The Cell Counting Kit-8 method and Ki-67 immunofluorescence were used to detect cell proliferation. Flow cytometry, quantitative real-time polymerase chain reaction, and western blots were used to detect cell cycle progression. In the high-concentration group, the invasion of H. pylori was observed by transmission electron microscopy. Results: It was found that H. pylori invaded the fibroblasts, with cytoplasmic localization. Analyses of cell proliferation and flow cytometry showed that H. pylori inhibited the proliferation of periodontal fibroblasts by causing G2 phase arrest. The inhibition of proliferation and G2 phase arrest were more obvious in the high-concentration group. In the low-concentration group, the G2 phase regulatory factors cyclin dependent kinase 1 (CDK1) and cell division cycle 25C (Cdc25C) were upregulated, while cyclin B1 was inhibited. However, in the high-concentration group, cyclin B1 was upregulated and CDK1 was inhibited. Furthermore, the deactivated states of tyrosine phosphorylation of CDK1 (CDK1-Y15) and serine phosphorylation of Cdc25C (Cdc25C-S216) were upregulated after H. pylori infection. Conclusions: In our model, H. pylori inhibited the proliferation of hPDLFs and exerted an invasive effect, causing G2 phase arrest via the Cdc25C/CDK1/cyclin B1 signaling cascade. Its inhibitory effect on proliferation was stronger in the high-concentration group.

• Journal of the Korean Society for Heat Treatment
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• v.1 no.1
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• pp.8-12
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• 1988

This study has been carried out to evaluate gaseous nitrocarburizing treatment undertaken for pure iron at $570^{\circ}C$ in an atmosphere containing 50% endothermic gas, generated from natural gas, and 50% ammonia. The results obtained from the experiment are as follows ; 1) The microstructure of gaseous nitrocarburized pure iron consists of the compound layer on the surface and the diffusion zone beneath it. The compound layer progresses uniformly into ferrite with a thickness of $20{\mu}$ obtained after treating for 3 hours. 2) Chemical analysis has shown that the compound layer has a C/N ratio of 0.19 and that the average combined interstitial content of the compound layer is about 30 atomic percent, which is close to the lower limit of the ${\varepsilon}$-carbonitride phase field in Fe-C-N phase diagram. 3) X-ray diffraction analysis has revealed that the compound layer consists mainly of the c.p.h. phase, ${\varepsilon}-Fe_3$(C.N) and a small amount of $Fe_4N$ and traces of ferrite are also present in the compound layer. 4) The microhardness of the compound layer is about 600 V.H.N and shows a relatively sharp fall-off at the compound layer/diffusion zome interface. 5) The average actual degree of ammonia dissociation is calculated to be 27% for a gaseous nitrocarburizing treatment carried out at $570^{\circ}C$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.261-262
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• 2006

• Journal of the Korean Society for Heat Treatment
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• v.10 no.2
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• pp.128-137
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• 1997

The formation processes of the retained austenite(${\gamma}_R$) in SHCP100 steel sheets were investigated in order to improve the transformation induced plasticity(TRIP) effect of ${\gamma}_R$. An excellent combination of elongation about 23% and high strength over 830 MPa was achieved by processing of intercritical annealing and isothermal holding. The mechanical properties of TRIP-aided dual phase steel was found to depend on the volume ratio of each phase and the volume fraction of ${\gamma}_R$. It was also noted that the proper mechanical stability of ${\gamma}_R$ improved the mechanical properties. In this work, the best balance of strength-ductility was obtained by holding the steel at $420^{\circ}C$ for 500sec. after annealing at $730^{\circ}C$ for 300 sec.

• Journal of Hydrogen and New Energy
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• v.17 no.3
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• pp.309-316
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• 2006

Co-ferrite was synthesized by HEBM (High Energy Ball Milling) with a stoichiometric (Co/Fe=0.5/2.5) mixture of CoO and $Fe_2O_3$ powders. The effect of milling time on the phase transformation of the mixture was investigated by XRD. Mono-phase solid solution of Co-ferrite, which was milled for 4 h and then calcined at $900^{\circ}C$ in the Ar atmosphere, was confirmed by XRD analysis. The composition and thermal reduction behavior of Co-ferrite were analyzed by TGA and XRF. As a result, oxygen deficient Co-ferrite was synthesized by HEBM and the weight decrease of the Co-ferrite, which was oxidized at $600^{\circ}C$ for 10h by $H_2O$ vapor, was 2.41 wt% during thermal reduction at $1300^{\circ}C$.