• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.445-448
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• 2005

PDP 유지전원단을 위한 고효율을 갖는 새로운 페이지 쉬프트 풀브릿지 컨버터를 제안한다. 제안된 컨버터는 Rectifier로 Voltage Doubler를 사용함으로서, 큰 사이즈의 Output Inductor가 없게 되어 간단한 구조를 가지게 되며 Rectifier Diodes의 전압 스트레스가 출력전압으로 클램핑되어서 스너버회로가 필요없다는 장점을 가지게 된다. 또한 넓은 영전압 스위칭 구간을 가지며, 트랜스포머의 기생성분인 Leakage 인덕터와 Voltage doubler의 캐패시터간의 공진을 이용함으로서 전류가 작은 RMS값을 가지게 되어서 낮은 도통손실과 Rectifier Diode의 전류 스트레스 또한 낮다는 장점을 가지게 된다. 본 논문을 통해 제안된 컨버터의 동작원리와 해석, 실험을 수행하였다.

• 반도체디스플레이기술학회지
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• 제4권2호
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• pp.39-43
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• 2005

In the study, in order to deposit TaN thin film for diffusion barrier and bottom electrode we made the Plasma Assisted ALD equipment and confirmed the electrical characteristics of TaN thin films grown PAALD method. Plasma Assisted ALD equipment depositing TaN thin film using PEMAT(pentakis(ethylmethlyamino) tantalum) precursor and NH3 reaction gas is shown that TaN thin film deposited high density and amorphous phase with XRD measurement. The degree of diffusion and reaction taking place in Cu/TaN (deposited using 150W PAALD)/$SiO_{2}$/Si systems with increasing annealing temperature was estimated for MOS capacitor property and the $SiO_{2}$, (600${\AA}$)/Si system surface analysis by C-V measurement and secondary ion material spectrometer (SIMS) after Cu/TaN/$SiO_{2}$ (400 ${\AA}$) layer etching. TaN thin film deposited PAALD method diffusion barrier have a good diffusion barrier property up to 500$^{\circ}C$.

• 반도체디스플레이기술학회지
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• 제22권1호
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• pp.28-32
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• 2023

Recently, the use of stable lithium nanostructures as substrates and electrodes for secondary batteries can be a fundamental alternative to the development of next-generation system semiconductor devices. However, lithium structures pose safety concerns by severely limiting battery life due to the growth of Li dendrites during rapid charge/discharge cycles. Also, enabling long cyclability of high-voltage oxide cathodes is a persistent challenge for all-solid-state batteries, largely because of their poor interfacial stabilities against oxide solid electrolytes. For the development of next-generation system semiconductor devices, solid electrolyte nanostructures, which are used in high-density micro-energy storage devices and avoid the instability of liquid electrolytes, can be promising alternatives for next-generation batteries. Nevertheless, poor lithium ion conductivity and structural defects at room temperature have been pointed out as limitations. In this study, a low-dimensional Graphene Oxide (GO) structure was applied to demonstrate stable operation characteristics based on Li+ ion conductivity and excellent electrochemical performance. The low-dimensional structure of GO-based solid electrolytes can provide an important strategy for stable scalable solid-state power system semiconductor applications at room temperature. The device using uncoated bare NCA delivers a low capacity of 89 mA h g-1, while the cell using GO-coated NCA delivers a high capacity of 158 mA h g−1 and a low polarization. A full Li GO-based device was fabricated to demonstrate the practicality of the modified Li structure using the Li-GO heterointerface. This study promises that the lowdimensional structure of Li-GO can be an effective approach for the stabilization of solid-state power system semiconductor architectures.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.32-37
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• 2023

For the potential applications in large-area OLED lightings, hydrogen fuel cells, and secondary batteries, we have performed an intermittent coating of high-viscosity polydimethylsiloxane using roll-to-roll slot die coater. During intermittent coating, dead zones inevitably appear where the thickness of PDMS patch films becomes non-uniform, especially at the leading/trailing edge. To reduce it, we have coated the PDMS patches by varying the process parameters such as the installation angle of the slot die head, coating speed, and patch interval. It is observed that the PDMS solution flows down and thus the thickness profile is non-uniform for horizonal intermittent coating, whereas the PDMS solution remaining on the head lip causes an increase in the PDMS thickness at the leading/trailing edges for vertical intermittent coating when the coating velocity is low. As the coating speed increases, however, the dead zone is shown to be reduced. It is addressed that the overall dead zone (the dead zone at the leading edge + the dead zone at the trailing edge) is smaller with horizontal intermittent coating than with vertical intermittent coating.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.130-135
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• 2023

Plasma-resistant ceramic (PRC) is a material used to prevent internal damage in plasma processing equipment for semiconductors and displays. The challenge is to suppress particles falling off from damaged surfaces and increase retention time in order to improve productivity and introduce the latest miniaturization process. Here, we confirmed the effect of suppressing plasma deterioration and reducing the etch rate through surface treatment of existing PRC with an initial illumination level of 200 nm. In particular, quartz glass showed a decrease in etch rate of up to 10%. Furthermore, it is believed that micro-scale secondary particles formed on the microstructure of each material grow as crystals during the fluoridation process. This is a factor that can act as a killer defect when dropped, and is an essential consideration when analyzing plasma resistance. The plasma etching suppression effect of the initial illumination is thought to be due to partial over etching at the dihedral angle of the material due to the sputtering of re-emission of Ar+-based cations. This means that plasma damage due to densification can also be interpreted in existing PRC studies. The research results are significant in that they present surface treatment conditions that can be directly applied to existing PRC for mass production and a new perspective to analyze plasma resistance in addition to simple etching rates.

• 한국재료학회지
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• 제22권12호
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• pp.696-700
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• 2012

(Na, K) $NbO_3$ thick film was successfully achieved using a sol-gel coating process with the addition of polyvinylpyrrolidone (PVP) to a metal alkoxide solution. The transparent coating solution, mixed with Nb:PVP = 1:1 in a molar ration, was synthesized by evaporating the solvent to over 62.5 wt%. Additive PVP increased the viscosity of the solution so that the coating thickness could be enhanced. The thickness of the (Na, K) $NbO_3$ film assisted by PVP was ca. 320 nm at the time of deposition; this value is four times thicker than that of the sample fabricated without PVP. Also, due to PVP binding with the OH groups of the metal alkoxide, the condensation reaction in the film was suppressed. The crystalline size of the (Na, K) $NbO_3$ films assisted by PVP was ca. 15 nm smaller than that of the film fabricated without PVP. After the sintering process at $700^{\circ}C$, the (Na, K) $NbO_3$ films were mainly composed of randomly oriented (Na, K) $NbO_3$ phase of perovskite crystal structure, including a somewhat secondary phase of $K_2Nb_4O_{11}$. However, by adding PVP, the content of the secondary phase became quite smaller than that of the sample without PVP. It was thought that the addition of PVP might have the effect of restraining the loss of potassium and that PVP could hold metalloxane by strong hydrogen bonding before complete decomposition. Therefore, the film thickness of the (Na, K) $NbO_3$ films could be considerably advanced and made more crack-free by the addition of PVP.

• 대한전자공학회논문지SD
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• 제44권12호
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• pp.12-17
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• 2007

본 연구에서는 전자빔 증착의 증착률이 MgO 보호막의 특성과 제작된 PDP의 방전 특성에 주는 영향에 대하여 연구, 분석 하였다. MgO 박막을 여러 조건의 증착률로 증착하였고, 이 후 결정 구조, 표면 거칠기, 박막 구조와 같은 특성을 XRD, AFM 등을 사용하여 측정, 평가하였다. 실험 결과와 Paschen law을 통해서 $5\AA/sec$의 증착률에서 이차전자방출이 최대가 되는 것을 확인할 수 있었으며, 동일 조건에서 방전 전압이 가장 작고, 발광 효율은 가장 큰 값을 갖는 것이 확인되었다. 또한 $5\AA/sec$의 (200) 결정 방향과 $F^+$ center 측정값도 가장 높게 측정되었다. XRD와 CL 스펙트럼의 결과를 통하여 이차전자방출계수가 MgO 박막의 분자 결정상의 $F/F^+$ centers구조와 관련 있음을 확인할 수 있었다.

• 한국학교보건학회지
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• 제3권2호
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• pp.63-87
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• 1990

The purpose of this study was to investigate the performance rate of regular health instruction by school nurses and its related factors. These data were collected by questionnaire in Mar. 1990. Total 986 school nurses who have been working primary, secondary schools in Seoul were given the questionnaire, and 672 school nurses' respectively, were finally analyzed. Analysis of the data was done utilizing SPSS/PC+for percentage, frequency, mean, $X^2$-test, t-test, ANOVA, correlation, regression. The major findings of this study were as follows : 1. Thc performance rate of regular health instruction by school nurses was 77.7% of 552 respondents. 2. The school nurses in primary school(87.0%) were more likely to perform regular health instruction than the school nurses in secondary school (63.8%). 3. The teachers of regular health instruction were more likely to display favorable attitudes toward need of health instruction. The school level was not statistically significant(P>0.05). 4. The evidence from the data analysis supported the proposition that the teachers of regular health instruction had more positive attitude toward the establishment of health subject(80.3%). The school level was statistically significant(P<0.05). 5. The school principal was a highly significant factor as it affected the performance rate of regular health instruction by school nurses. The school level was statistically significant(P<0.001). 6. The length of past career, the degree of self confidence on health instruction, the need of health instruction did affect the performance rate of regular health instruction by school nurses. On the basis of the above mentioned, so as for regular health instruction of school to be activated more throughly, regular class must be introduced in the form of establishment of health subject, enhancement of quality on the part of school nurses, made and various methods for enhancing perception toward the regular health instruction on the part of school principal are to be carried out.

• 대한지구과학교육학회지
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• 제7권3호
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• pp.303-312
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• 2014

In order to foster 'creative convergence talents' teachers and pre-service teachers who possess a certain degree of creativity must learn about this new approach as part of their teacher training. In this study, we attempted to identify the implications on the curriculum of the teacher education-training college in question by analysing secondary school teachers' and pre-service teachers' creativity and by collecting sufficient data to develop a positive feedback model for selecting, cultivating, and appointing pre-service teachers who fulfil the requirements of said college of education. Such teachers will display the commitment and professionalism to fulfil their teaching duties in the best possible manner and will consistently produce valuable contributions to their chosen subject matter and integrate these into their daily teaching. These teachers will complete all their tasks in a creative way, including student guidance, administrative duties, and academic lessons. The factors that distinguished creative teachers from others included originality and fluency. Our test group comprised 216 pre-service teachers as well as 137 fully qualified teachers. Teachers' understanding of the factors required in order to qualify as a 'creative and committed teacher' was very low. We provided data to the college of education to increase creativity when selecting teachers and curricula based on an analysis of perceptions of creativity provided by teachers and pre-service teachers.

• 한국학교수학회논문집
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• 제19권4호
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• pp.459-478
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• 2016

교육에서의 테크놀로지 사용으로 인한 혜택과 이에 대한 관심이 커지면서, 테크놀로지를 통합한 수학 수업에서 교사의 역할이 더욱 중요해졌다. 따라서 예비 교사의 기술적 교육학적 내용 지식 (Technological Pedagogical Content Knowledge: TPACK)을 발전시키는 것이 중요하며, 이는 그들의 신념에 영향을 받는다. 본 연구에서는 예비 고등 수학 교사들의 수학수업에서의 테크놀로지 사용에 관한 경험과 신념이 그들의 TPACK에 어떻게 영향을 미치는지 조사 하였다. 연구 결과, 테크놀로지 사용 경험이 많고 학생 중심적 테크놀로지 사용에 관한 신념을 가진 예비 교사들이, 경험이 적고 교사 중심의 신념을 가진 예비 교사들 보다 테크놀로지에 관한 지식이 높은 것으로 나타났다. 예비 교사들의 TPACK과 신념의 관계에 대한 이해는 예비 교사들이 TPACK을 발전 시키고 테크놀로지 통합 수업을 할 수 있도록 하기 위해, 교사 교육 프로그램이 어떻게 지원 해야 할 것인지에 관한 통찰을 제공한다.