인터넷을 활용한 영어 읽기: 한국 중학생 학습 사례 연구

허기석 ( Ki Seok Heo ) 한국중등영어교육학회 2010 중등영어교육 Vol.3 No.1

The purpose of this study is to examine whether learning reading in English using the Internet is effective for Korean middle school students. A 4-week reading program was developed and taught through an Internet homepage. A total of 26 students participated in pre-, while-, and post-reading activities with five different types of reading comprehension questions; main idea, reference, details, sentence completion, and inference. The effect of learning through the Internet was analyzed by student questionnaires and reading comprehension tests that were conducted before and after the study. Almost all the students improved in their interest in learning reading and found the use of Internet quite useful probably thanks to diverse use of audio-visual materials, active participation through group works and interactive search of information on the Internet. The posttest result also showed significant improvement when compared to that of the pretest regardless of the question types, students`` pretest scores, overall English proficiency level, and their gender. Based on these results, the Internet-mediated reading program incorporated in this study seemed to have positive effect on the development of young EFL learner``s reading skills and attitude. The Internet is now a part of daily work for most elementary and middle school students in Korea. They have quick access to vast amount of information and their chance of communicating with native English speakers through the Internet is also on the rise. Therefore, if on-line reading materials are used more actively and suitably in classrooms, it could make a very efficient resource for many EFL students.

고리형 황화물을 포함하는 폴리아크릴레이트 합성과 설폭사이드 및 설폰 변환을 통한 굴절률 변화

허기석(Gisuk Heo),김새미(Saimi Kim),도정윤(Jung Yun Do) 한국고분자학회 2016 폴리머 Vol.40 No.3

황을 포함하는 고리형 아크릴레이트 단분자를 사용하여 고굴절률의 공중합 아크릴고분자 4종을 합성하였다. 황을 포함한 7-각 고리, 1,3-dithiane, 1,3-dithiolane 유도체를 사용하여 4가지의 아크릴 단분자를 합성하였고, 이를 methyl methacrylate(MMA)와 중량비로 3:7의 공중합고분자를 합성하였다. 오존(O₃)과 3-chloroperoxybenzoic acid (m-CPBA)를 사용하여 고분자에 포함된 황을 산화시켜 각각 SO와 SO₂를 갖는 고분자를 얻었다. 적외선 흡수 분광법(FTIR)과 수소핵자기공명분광(1H NMR) 분석을 통해 이러한 산화반응이 선택적으로 잘 진행되었음을 확인하였다. 합성된 고분자에 포함된 황의 함량에 따라 굴절률이 증가되는 것을 관찰하였다. 황이 SO로 산화되었을 때는 고분자의 굴절률이 증가하였고 SO₂로 산화되었을 때는 크게 감소하였다. SO₂를 갖는 단분자로 합성된 고분자와, 고분자의 산화로 SO₂ 를 갖는 고분자가 서로 유사한 성질을 보임으로써 고분자에 존재하는 황이 대부분 산화되었음을 확인하였다. 황산화 반응을 통해 고분자의 Abbe number는 증가되었다. 파장에 따른 굴절률을 계산하였고 산화반응을 통한 굴절률 변화가 모든 파장에 대해 유사하게 일어났음을 확인하였다. Polyacrylates with pending alkylsulfur groups were prepared to examine the changes in refractive index (RI) induced by sulfur oxidation. Four methacrylate monomers having cyclic alkylsulfur groups, such as 1,3-dithiane and 1,3- dithiolane derivatives, and 3,6-dithiacycloheptanol were developed. The monomers were copolymerized with methyl methacrylate through a radical polymerization. Oxidation of the prepared sulfur-polymers by O₃ and 3-chloroperoxybenzoic acid led to the formation of the corresponding SO and SO₂-polymers, respectively. The selective transformation of sulfur occurred completely and confirmed by FTIR and 1H NMR analysis. The RI of the polymer increased and decreased due to the formation of SO and SO₂, respectively. The SO₂-polymer exhibited a RI comparable to a polymer that was prepared using a sulfone-monomer. The Abbe number of the polymer increased after oxidation. The RI dispersion over various wavelengths was compared before and after oxidation.

조사위치의 주변환경을 고려한 표준관입시험 결과와 전단파속도의 상관관계

허기석(Heo, Giseok),곽동엽(Kwak, Dongyoup) 대한토목학회 2020 대한토목학회 학술대회 Vol.2020 No.10

지형특성에 따른 N-Vs의 상관관계

허기석(Heo, Gi Seok),곽동엽(Kwak, Dong Youp) 대한토목학회 2023 대한토목학회 학술대회 Vol.2023 No.10

유연 OLED 조명 응용을 위한 플렉시블 TCO 개발 현황

김태원,허기석,박종운,이종호,Kim, Tae-Won,Heo, Gi-Seok,Park, Jong-Un,Lee, Jong-Ho 한국전기전자재료학회 2010 전기전자재료 Vol.23 No.4

전기방사에 의한 PVdF-HFP 나노섬유의 제조 특성

장덕례,조용준,허기석,Chang, Duk-Rye,Cho, Yong-Jun,Heo, Gi-Seok 한국섬유공학회 2006 한국섬유공학회지 Vol.43 No.5

PVdF-HFP nanofibers were fabricated by co-electrospinning technique. The fabricated PVdF-HFP nanofibers were characterized using scanning electron microscopy (SEM). We have evaluated systematically the effects of the most important processing parameters: voltage, solution concentration and tip to collector distance, on the morphology of the formed fibers. 7.5 wt%$\sim$20 wt% PVdF-HFP nanofibers of about 495 nm$\sim$2.26 $\mu$m in diameter were fabricated. The average diameter of PVdF-HFP nanofibers increased with increasing concentration of PVdF-HFP solution. It is found that the concentration of PVdF-HFP polymer solution strongly affects the size of the fibers so that diameter of fibers increases with increasing concentration of the solution. Also the applied voltage is strongly correlated with the distribution of nanofibers. In addition, we found an evidence that electrostatic effects influence the stability of discharge.

비닐하우스 철항의 인발저항력 추정을 위한 현장 및 실내시험 결과 분석

최인혁(Choi, In Hyeok),허기석(Heo, Gi Seok),이진영(Lee, Jin Young),곽동엽(Kwak, Dong Youp) 대한토목학회 2023 대한토목학회 학술대회 Vol.2023 No.10

발광 페인트와 혼합 된 폴리머 분산 액정(PDLC) 기반의 자체 발광 스마트 윈도우

안태준(Tae Jun Ahn),허기석(Gi Seok Heo),유윤섭(Yun Seop Yu) 한국정보통신학회 2020 한국정보통신학회 종합학술대회 논문집 Vol.24 No.2

TIZO/Ag/TIZO 다층막 투명전극을 이용한 폴리에스터 아크릴레이트 기반 고분자분산액정의 전기광학적 특성 연구

조정대 ( Jung-dae Cho ),허기석 ( Gi-seok Heo ),홍진후 ( Jin-who Hong ) 한국공업화학회 2022 공업화학 Vol.33 No.1

본 연구에서는 RF/DC 마그네트론 증착법을 이용하여 유리 기판 상에 실온에서 TIZO/Ag/TIZO 다층막 투명전극 필름을 증착하였다. 전체 박막 두께 60 nm TIZO/Ag/TIZO (10 nm/10 nm/40 nm)로 이루어진 다층막의 경우 650 nm에서 투과도는 86.5%, 면저항 값은 8.1 Ω/□를 나타냈으며, 적외선(열선)을 효과적으로 차단할 수 있는 투과도 특성 때문에 향후 에너지 절약형 스마트 윈도우로서의 적용도 가능할 것으로 판단된다. TIZO/Ag/TIZO 다층막 투명전극을 적용한 폴리에스터 아크릴레이트 기반 고분자분산액정(polymer-dispersed liquid crystal, PDLC) 시스템에 있어서 액정과 prepolymer의 함량비, PDLC 코팅층의 두께 및 자외선 세기 변화에 따른 전기광학 특성 및 표면 형태학에 미치는 영향이 조사되었다. 15 μm의 PDLC 층 두께에 1.5 mW/cm2의 UV 세기로 광경화된 TIZO/Ag/TIZO 다층막 투명전극 적용 PDLC 셀이 전반적으로 양호한 구동 전압과 on-state 투과도 및 뛰어난 off haze를 나타냈으며, PDLC 복합체의 고분자 매트릭스 표면에 형성된 액정 droplet들은 입사광을 효율적으로 산란시킬 수 있는 1~3 μm 크기를 갖고 있었다. 또한, 본 연구에서 제조된 TIZO/Ag/TIZO 다층막 투명전극 적용 PDLC 기반 스마트 윈도우는 연한 갈색의 색조를 띠고 있어서 심미적 측면에서 색다른 장점을 부여할 것으로 기대된다. Ti-In-Zn-O (TIZO)/Ag/TIZO multilayer transparent electrodes were prepared on glass substrates at room temperature using RF/DC magnetron sputtering. Obtained multilayer structure comprising TIZO/Ag/TIZO (10 nm/10 nm/40 nm) with the total thickness of 60 nm showed a transmittance of 86.5% at 650 nm and a sheet resistance of 8.1 Ω/□. The multilayer films were expected to be applicable for use in energy-saving smart window based on polymer-dispersed liquid crystal (PDLC) because of their transmittance properties to effectively block infrared rays (heat rays). We investigated the effects of the content ratio of prepolymer, the thickness of the PDLC coating layer, and the ultraviolet (UV) light intensity on electro-optical properties, and the surface morphology of polyester acrylate-based PDLC systems using new TIZO/Ag/TIZO transparent conducting electrodes. A PDLC cell with a thickness of 15 μm PDLC layer photocured at an UV intensity of 1.5 mW/cm2 exhibited good driving voltage, favorable on-state transmittance, and excellent off-haze. The LC droplets formed on the surface of the polymer matrix of the PDLC composite had a size range of 1 to 3 μm capable of efficiently scattering incident light. Also, the PDLC-based smart window manufactured using TIZO/Ag/TIZO multi-layered transparent electrodes in this study exhibited a light brown, which will have an advantage in terms of aesthetics.

비닐하우스 기초 토양의 다짐률 변화에 따른 전단강도 특성

임성윤 ( Lim Seongyoon ),허기석 ( Heo Giseok ),곽동엽 ( Kwak Dongyoup ) 한국농공학회 2021 한국농공학회논문집 Vol.63 No.6

Greenhouses have been damaged due to the uplift pressure from strong wind, for which rebar piles are often installed near the greenhouse to resist the pressure. For the effective design of rebar piles, it is necessary to access the shear strength of soil on which the greenhouse is constructed. This study experimentally evaluates the shear strength of the soil beneath the greenhouse. Four soil samples were collected from four agricultural sites, and prepared for testing with 75, 80, 85, and 90% compaction rates. One-dimensional unconfined compression test (UC), consolidated-undrained triaxial test (CU), and resonant column test (RC) were performed for the evaluation of shear strength and shear modulus. Generally, the higher shear strength and modulus were observed with the higher compaction rates. In particular, the UC shear strength increases with the increase of #200 sieve passing rate. Resulting from the CU test, the sample with the most of coarse soil had the highest friction angle, but the variation is small among samples. Resulting from the CU and RC tests, the ratio of maximum shear modulus with the major principle stress at failure was the higher at the finer soil. The ratio was two to three times greater than the ratio from the standard sand. This indicates that the shear strength is lower for the fine soil than the coarse soil at the same shear modulus. The results of this study will be a useful resource for the estimation of the pull-out strength of the rebar pile against the uplift pressure.