• 대한화학회지
• /
• 제59권6호
• /
• pp.520-532
• /
• 2015

이 연구의 목적은 CoRe를 활용한 교육실습 수업지도 과정에서 어떠한 내용의 지도가 이루어지며, 이 과정에서 CoRe의 역할과 그것이 예비교사들의 전문성 개발에 미치는 영향은 무엇인지를 알아보는 것이었다. 이 연구는 질적 사례연구로, 1명의 실습 지도교사와 2명의 예비교사의 CoRe 논의과정, 예비교사가 진행하는 수업의 관찰, 면담 등의 자료를 수집하여 귀납적으로 분석하였다. CoRe를 바탕으로 한 논의과정에서 예비교사들은 자신의 오개념을 확인하고 개념을 명료화하였으며, 서로의 아이디어를 공유하고, 부족한 지식을 보완하며, 새로운 전략을 구성해나갔다. 지도교사는 자신의 구성주의적 교수 지향을 기반으로 자신의 교수 경험을 전달하였다. 이 과정에서 CoRe는 예비교사들에게 지도교사의 지도 과정을 안내하는 역할, 지도교사의 PCK를 드러내도록 도와주는 역할, 논의과정에서 그들의 대화를 도와주는 도구로서의 역할을 하여 교육실습에서 지도교사의 수업지도를 도와주는 유용한 틀임을 확인하였다. 예비교사들은 CoRe 작성과정을 통해 수업 준비를 위한 유용한 틀을 제공받았고, 수업계획 단계에서 지도교사와 함께 CoRe를 개발하면서 교과 내용 지식과 교육과정 지식, 학생의 이해에 대한 지식을 포함하는 PCK 신장에 긍정적 영향을 받았다. 또한, PCK의 구성요소를 이해하고 학생과 교수활동, 과학 교사로서의 자신에 대한 긍정적인 인식 변화를 경험하였다.

• 한국세라믹학회지
• /
• 제42권11호
• /
• pp.763-769
• /
• 2005

Ferroelectric $ReMnO_3$(Re:Ho, Er) thin films were deposited on Si(100) substrate by Metal-Organic Chemical Vapor Deposition (MOCVD). Crystallinity and electric properties of $ReMnO_3$(Re:Ho, Er) thin films were investigated as a function of thermal heat treatment process, CHP (Conventional Heat-treatment Process) and RTP (Rapid Thermal Process). $ReMnO_3$(Re:Ho, Er) thin films prepared by RTP showed higher c-axis preferred orientation and homogeneous surface roughness than those prepared by CHP. The remnant polarization of ferroelectric hysteresis loop of $ReMnO_3$(Re:Ho, Er) thin films was strongly dependent on the c­axis preferred orientation of hexagonal single phase, and the leakage current characteristics of thin films were dependent on the homogeneity of grain size as well as surface roughness of thin films.

• 한국전기전자재료학회논문지
• /
• 제29권3호
• /
• pp.135-140
• /
• 2016

In this study, we developed the solution-processed PMMA-$HfO_x$ hybrid ReRAM devices to overcome the respective drawbacks of organic and inorganic materials. The performances of PMMA-$HfO_x$ hybrid ReRAM were compared to those of PMMA- and $HfO_x$-based ReRAMs. Bipolar resistive switching behavior was observed from these ReRAMs. The PMMA-$HfO_x$ hybrid ReRAMs showed a larger operation voltage margin and memory window than PMMA-based and $HfO_x$-based ReRAMs. The reliability and electrical instability of ReRAMs were remarkably improved by blending the $HfO_x$ into PMMA. An Ohmic conduction path was commonly generated in the LRS (low resistance state). In HRS (high resistance state), the PMMA-based ReRAM showed SCLC (space charge limited conduction). the PMMA-$HfO_x$ hybrid ReRAM and $HfO_x$-based ReRAM revealed the Pool-Frenkel conduction. As a result of flexibility test, serious defects were generated in $HfO_x$ film deposited on PI (polyimide) substrate. On the other hand, the PMMA and PMMA-$HfO_x$ films showed an excellent flexibility without defect generation.

• 전기학회논문지
• /
• 제65권8호
• /
• pp.1369-1375
• /
• 2016

A rapid progress of the next-generation non-volatile memory device has been made in recent years. Metal/insulator/Metal multi-layer structure resistive RAM(ReRAM) has attracted a great deal of attention because it has advantages of simple fabrication, low cost, low power consumption, and low operating voltage. This paper describes the working principle of the ReRAM device, a review of fabrication techniques, and characteristics of flexible ReRAM devices using graphene oxide as an insulating layer and ReRAM devices using multi-layered insulator. The switching characteristics of the above ReRAM devices have been compared. The oxidized graphene could be employed as an insulator of next generation ReRAM devices.

• Current Photovoltaic Research
• /
• 제10권2호
• /
• pp.62-71
• /
• 2022

The Global RE100 campaign is a one of the voluntary campaign, but it has a lot of influence on domestic companies that have not yet joined the Global RE100. Accordingly, the Korean government introduced the Korean RE100 (K-RE100) system to prepare an institutional mechanism for domestic companies to respond to RE100. However, in Korea, due to the high LCOE of renewable energy and institutional limitations of the power transaction system, there is a limit for companies to implement RE100 in various ways. Therefore, in this study, the implementation cost of RE100 for green tariff, REC purchase, third-party PPA, direct(or corporate) PPA, and self-generation was compared and analyzed to derive the order of implementation with the net present value (NPV) of costs incurred over 20 years. As a result, self-construction was analyzed as the most economical method, but the implementation through the green tariff seemed to be the most realistic implementation method so far. However, considering the gradually falling LCOE, third-party PPA and direct PPA could be secured competitiveness against green tariff in 2025 and 2026. Then it could allow the companies to have various portfolios for implementation of RE100.

• KIEAE Journal
• /
• 제13권6호
• /
• pp.67-75
• /
• 2013

The present duration of 5 years in the Korea Green Building Certification(G-SEED) should be re-set taking into account with the needs for renewal of re-certification criteria. This study methods is to analyze the differences between the characteristics of the certification system of green building of domestic and foreign and to seek the improvement to derive the problem of detailed evaluation items of the examination. The purpose of this study is to identify some problems of re-certification criteria in the G-SEED System and to propose the renewal of certification system. Analysis of the rating criteria with a few re-certified examples of office buildings have been made. Some measures to improve the re-certification have been suggested as follows; (1) it is strongly suggested to establish re-certification rating systems that is not yet made, (2) the new criteria of re-certification bring into focus on whether buildings maintain the environmental performances of the initial status certified, and (3) thus the effective duration of re-certification needs to re-set flexibly in a way to confirm to the initial environmental performances and maintenance conditions certified.

• 대한핵의학회지
• /
• 제32권5호
• /
• pp.425-432
• /
• 1998

목적: Re-188을 치료용 방사성핵종으로 사용하기 위하여 W-188/Re-188 발생기를 병원 내에서 사용할 때 발생기 정도관리에 관한 실험을 실시하였다. 대상 및 방법: 알루미나 컬럼을 사용한 W-188/Re-188 발생기를 대상으로 하여 약 300일간 정도관리 실험을 하였다. 생리식염수 20 ml을 사용하여 발생기로부터 Re-188을 용출한 후 Re-188 용출액의 방사화학적 순도를 보기 위하여 박층크로마토그라피를 실시하고 감마에너지 스펙트럼을 측정하였다. 발생기의 화학순도실험으로 알루미늄의 용출을 알루미늄 이온 확인 키트를 사용하여 확인하였다. Re-188 용출액에 불순물로 있을 수 있는 모핵종 W-188은 감마에너지 스펙트럼으로 확인하였다. Re-188 용출액의 pH를 측정하였으며 발열원 검사로 LAL 검사를 시행하였다. Re-188 용출액을 이온교환컬럼을 사용하여 농축하였다. 결과: 용출분획의 Re-188 방사능양을 전체 용출한 방사능 양에 대한 백분율로 계산하였을 때 $5{\sim}10 ml$ 사이의 용출액이 전체 방사능양의 약 76%를 차지하였다. W-188의 방사능에 대한 Re-188 용출액의 방사능비는 270일간 평균 $67.4{\pm}7.0%$였으며, 용출 간격을 3일 이상 두었을 때가 높았다. 용출한 Re-188의 방사화학적 순도는 거의 100%였으며, 감마에너지 스펙트럼상에서 정점은 $135{\sim}188 keV$ 사이에 나타났다. 알루미늄 유출은 없었으며, W-188의 유출 역시 없었다. Re-188 용출액의 pH는 3이었으며, 발열성물질은 검출되지 않았다. 이온교환컬럼을 사용하여 Re-188을 농축하였을 때 회수율은 87%였다. 결론: 이 연구에서 사용한 W-188/Re-188 발생기는 각종 임상연구에 사용하기에 충분한 수준의 정도관리 결과를 나타내었다.

• 복식
• /
• 제65권5호
• /
• pp.113-125
• /
• 2015

The purpose of this paper is to study the $boutonni{\grave{e}}re$, a floral decoration, history of $boutonni{\grave{e}}re$, a floral decoration, with a focus on its aesthetics, its practical use and its traditional meaning. After the examination of its history, the paper, recreated the proceeds by taking into consideration both the contemporary men's fashion, as well as the $boutonni{\grave{e}}re$ designs of the past. The three factors of contemporary $boutonni{\grave{e}}re$ design, in brief, are its historical meaning, the visual aesthetics and the wearability. In this paper, the research and design steps are as followed below. First, the paper examined the history of men's fashion leading up to the twenty-first century in order to get a deeper understanding of the history of $boutonni{\grave{e}}re$. Second, the paper attempted to find the most suitable fabric materials and flowers for the $boutonni{\grave{e}}re$, in order to produce diverse $boutonni{\grave{e}}re$ that can be worn in any season and occasion. As for the fabrics that can be used to make the $boutonni{\grave{e}}re$, organza can be used for the S/S season, and wool, tweed and suede can be used for the F/W season. The major characteristics that differentiate the kinds of $boutonni{\grave{e}}re$ are the "Carnation" and the "Rose of Sharon". The 'Rose of Sharon' $boutonni{\grave{e}}re$ as the symbol of our nation possesses an intricate meaning and practical function, so that this $boutonni{\grave{e}}re$ is used as an alternative badge of the national assembly and other social-national institutions and their members. This idea expands into other social and individual features that the $boutonni{\grave{e}}re$ is a differentiated fashion item that provides other personal styles and expresses individuality.

• 한국전기전자재료학회논문지
• /
• 제24권3호
• /
• pp.219-223
• /
• 2011

Rhenium-Iridium(Re-Ir) thin films were deposited onto the tungsten carbide(WC) molding core by sputtering system. The Re-Ir films were prepared by multi-target sputtering with iridium, rhenium and chromium as the sources. Argon and nitrogen were inlet into the chamber to be the plasma and reactive gases. The Re-Ir thin films were prepared with targets having atomic percent of 3:7 and the Re-Ir thin films were formed with 240 nm thickness. The Re-Ir thin films on tungsten carbide molding core were analyzed by scanning electron microscope(SEM) and surface roughness. Also, adhesion strength and coefficient friction of Re-Ir thin film were examined. The Re-Ir coating technique has been intensive efforts in the field of coating process because the coating technique and process have been their feature, like hardness, high elasticity, abrasion resistance and mechanical stability and also have been applied widely the industrial and biomedical areas. In this report, tungsten carbide(WC) molding core was manufactures using high performance precision machining and the efforts of Re-Ir coating on the surface roughness.

• Wind and Structures
• /
• 제30권5호
• /
• pp.475-483
• /
• 2020

This work investigates Reynolds number Re (= 50 - 200) effects on the flows around a single cylinder and the two tandem (center-to-center spacing L^⁎= L/D = 4) cylinders, each of a diameter D. Vorticity structures, Strouhal numbers, and time-mean and fluctuating forces are presented and discussed. For the single cylinder, with increasing Re in the range examined, the vorticity magnitude, Strouhal number and fluctuating lift all monotonically rise but time-mean drag, vortex formation length, and lateral distance between the two rows of vortices all shrink. For the two tandem cylinders, the increase in Re leads to the formation of three distinct flows, namely reattachment flow (50 ≤ Re ≤ 75), transition flow (75 < Re < 100), and coshedding flow (100 ≤ Re ≤ 200). The reattachment flow at Re = 50 is steady. When Re is increased from 75 to 200, the Strouhal number of the two cylinders, jumping from 0.113 to 0.15 in the transition flow regime, swells to 0.188. The two-cylinder flow is more sensitive to Re than the single cylinder flow. Fluctuating lift is greater for the downstream cylinder than the upstream cylinder while time-mean drag is higher for the upstream cylinder than for the other. The time-mean drags of the upstream cylinder and single cylinder behaves similar to each other, both declining with increasing Re.