FRP-콘크리트 합성말뚝 시편의 압축강도실험

이영근,최진우,박준석,윤순종,Lee, Young-Geun,Choi, Jin-Woo,Park, Joon-Seok,Yoon, Soon-Jong 한국복합신소재구조학회 2011 복합신소재구조학회논문집 Vol.2 No.4

이 연구는 새로운 형태의 FRP-콘크리트 합성말뚝인 하이브리드 CFFT(HCFFT)를 개발하는 과정의 일부이다. 이 논문에서는 CFFT와 HCFFT의 압축강도실험을 통하여 구조적 거동을 분석하였다. 압축강도실험에 앞서 PFRP와 FFRP 재료의 역학적 성질을 조사하였다. HCFFT 압축강도실험은 콘크리트 강도와 FFRP의 두께를 변수로 하여 실험을 수행하였다. 그리고, FFRP 두께를 변수로 PFRP를 제외한 CFFT 실험체를 제작하고 실험을 수행하여 HCFFT와 비교 분석하였다. 실험 결과, HCFFT의 압축강도는 CFFT에 비하여 11~47% 향상되는 것으로 나타났다. 실험구간내의 필라멘트 와인딩 FRP 보강두께의 증가에 따른 HCFFT의 압축강도는 선형으로 증가시키는 것으로 나타났다. 또한 실험체와 동일한 조건의 유한요소해석을 수행하였다. 해석결과는 실험결과에 비하여 모든 시편에서 약간 작은 값을 보였으며, 0.14%에서 17.95%까지의 오차범위 내에 있음을 알 수 있었다. In this paper, we present a part of results to develop new type hybrid FRP-concrete composite pile (i.e., concrete filled fiber reinforced plastic circular tubes, hybrid CFFT, HCFFT). The purpose of this paper is to evaluate compressive loading capacity through compressive strength test. Before compressive strength test of HCFFT, we investigated mechanical properties of pultruded fiber reinforced plastic (PFRP) and filament winding fiber reinforced plastic (FFRP). For estimating the compressive strength of HCFFT, uni-axial compression strength tests of HCFFT compression members were conducted. The test variables are compressive strengths of concrete and thickness of FFRP. In addition, uni-axial compression strength tests of concrete filled fiber reinforced plastic circular tube (CFFT) except PFRP members were conducted. The test variable in the test is thickness of FFRP. From the test result, the compressive strength of the HCFFT in larger than compressive strength of CFFT as much as 47%. It can be observed that the uni-axial compressive strength of the HCFFT increased if the concrete strength and the thickness of exterior filament winding FRP tube increased. In addition, the finite element analysis result is compared with the experimental result. The difference between the experimental and FEM results is in the range of 0.14% to 17.95%.

산화환원반응용 백금 촉매 지지체를 위한 질소 도핑된 단백질계 탄소의 제조

이영근,안건형,안효진,Lee, Young-geun,An, Geon-hyeong,Ahn, Hyo-Jin 한국재료학회 2018 한국재료학회지 Vol.28 No.3

Nitrogen (N)-doped protein-based carbon as platinum (Pt) catalyst supports from tofu for oxygen reduction reactions are synthesized using a carbonization and reduction method. We successfully prepare 5 wt% Pt@N-doped protein-based carbon, 10 wt% Pt@N-doped protein-based carbon, and 20 wt% Pt@N-doped protein-based carbon. The morphology and structure of the samples are characterized by field emission scanning electron microscopy and transmission electron micro scopy, and crystllinities and chemical bonding are identified using X-ray diffraction and X-ray photoelectron spectroscopy. The oxygen reduction reaction are measured using a linear sweep voltammogram and cyclic voltammetry. Among the samples, 10 wt% Pt@N-doped protein-based carbon exhibits exellent electrochemical performance with a high onset potential of 0.62 V, a high $E_{1/2}$ of 0.55 V, and a low ${\Delta}E_{1/2}=0.32mV$. Specifically, as compared to the commercial Pt/C, the 10 wt% Pt@N-doped protein-based carbon had a similar oxygen reduction reaction perfomance and improved electrochemical stability.

유럽너도밤나무 군락과 독일가문비 조림지의 생태특성 비교

이영근,조현제,Lee, Young-Geun,Cho, Hyun-Je 한국생태학회 2000 Journal of Ecology and Environment Vol.23 No.5

독일가문비 조림지를 식물사회학적 식생조사를 하여 이곳의 원식생인 유럽너도밤나무군락과의 비교를 통해 식생구조, 종조성, 생태계, 생활형의 차이점이 있는지를 조사하였다 독일가문비 조림지에서의 평균출현 종수는 13종이었으며, 이들 종은 생태적 분포특성에 따라 유럽너도밤나무림에 나타나는 종, 자연 침엽수림에 나타나는 종, 그리고 개벌 후의 나지에 나타나는 종 등 크게 세가지 그룹으로 구분되었다. Luzulo-Fagetum군락에서는 Luzula luzuloides가 우점종이나 독일가문비 조림지에서는 Avenella flexuosa가 우점하고 있었다. 조림지 내의 초본식물을 Ellenberg의 지표종에 따라 분석한 결과, 호광성식물과 강산성식물이 증가하고 있었다. 한편 생활형 분석에서는 지표식물, 지상식물 그리고 반지중식물이 증가하고 지중식물은 감소하는 경향을 나타내었다. 위의 결과들은 과거 유럽너도밤나무군락이 우점하던 지역에 조성된 독일가문비 조림지가 생태학적 불안정하다는 것을 보여준다. Picea abies plantation in Mt. Eifel, Germany was studied phytosociologically, with special reference to species composition, structure, ecology and dormancy form, comparing to those of Fagus sylvastica population that once dominated the P. abies plantation. Thirteen plant species appeared on average. According to their ecological distribution, they were classified into three groups, F sylvastica forests, natural coniferous forests and bare-land after clear-cutting. In Luzulo-Fagetum population, Luzula luzuloides was the dominated species while in P. abies plantation was dominated by Avenella flesuosa. In assessment of herbaceous plants by indicator species of Ellenberg, increasing number of shade-intolerant species and acid-tolerant species occurred. In analysis of plant dormancy form, species of Chamaephytes, Phanerophytes and Hemikryptophytes increased, while that of Geophytes decreased. As a result, we found P. abies plantation unstable in ecological aspects.

인천국제공항의 미래성장을 위한 허브화 전략방안

이영근,Lee, Young-Geun 대한교통학회 2011 교통 기술과 정책 Vol.8 No.4

The Flexural Strengthening Effect of I-Shape PFRP Member Using Carbon Fiber Sheet

이영근,김선희,이강연,윤순종,Lee, Young-Geun,Kim, Sun-Hee,Lee, Kang-Yeon,Yoon, Soon-Jong Korean Society for Advanced Composite Structures 2013 복합신소재학회논문집 Vol.4 No.2

In recent years, fiber reinforced polymer plastic composites are readily available in the construction industry. Fiber reinforced polymer composite has many advantages such as high specific strength and high specific stiffness, high corrosion resistance, light-weight, magnetic transparency, etc. In this paper, we present the result of investigation pertaining to the flexural behavior of flange strengthened I-shape pultruded fiber reinforced polymer plastic (PFRP) member using carbon fiber sheet (CFRP sheet). Test variable is consisted of the number of layers of strengthening CFRP sheet from 0 to 3. From the experimental results, flexural strengthening effect of flange strengthened I-shape PFRP member using CFRP sheet is evaluated and it was found that 2 layers of strengthening CFRP sheet are appropriate considering efficiency and workability.

산소환원반응을 위한 탄화철이 내재된 질소 도핑된 탄소의 제조

이영근,안건형,안효진,Lee, Young-Geun,An, Geon-Hyoung,Ahn, Hyo-Jin 한국재료학회 2018 한국재료학회지 Vol.28 No.11

The design of non-precious electrocatalysts with low-cost, good stability, and an improved oxygen reduction reaction(ORR) to replace the platinium-based electrocatalyst is significant for application of fuel cells and metal-air batteries with high energy density. In this study, we synthesize iron-carbide($Fe_3C$) embedded nitrogen(N) doped carbon nanofiber(CNF) as electrocatalysts for ORRs using electrospinning, precursor deposition, and carbonization. To optimize electrochemical performance, we study the three stages according to different amounts of iron precursor. Among them, $Fe_3C$-embedded N doped CNF-1 exhibits the most improved electrochemical performance with a high onset potential of -0.18 V, a high $E_{1/2}$ of -0.29 V, and a nearly four-electron pathway (n = 3.77). In addition, $Fe_3C$-embedded N doped CNF-1 displays exellent long-term stabillity with the lowest ${\Delta}E_{1/2}=8mV$ compared to the other electrocatalysts. The improved electrochemical properties are attributed to synergestic effect of N-doping and well-dispersed iron carbide embedded in CNF. Consequently, $Fe_3C$-embedded N doped CNF is a promising candidate for non-precious electrocatalysts for high-performance ORRs.

Fabrication of Boron-Doped Activated Carbon for Zinc-Ion Hybrid Supercapacitors

이영근,장해남,안건형,Lee, Young-Geun,Jang, Haenam,An, Geon-Hyoung Materials Research Society of Korea 2020 한국재료학회지 Vol.30 No.9

Zinc-ion hybrid supercapacitors (ZICs) have recently been spotlighted as energy storage devices due to their high energy and high power densities. However, despite these merits, ZICs face many challenges related to their cathode materials, activated carbon (AC). AC as a cathode material has restrictive electrical conductivity, which leads to low capacity and lifetime at high current densities. To overcome this demerit, a novel boron (B) doped AC is suggested herein with improved electrical conductivity thanks to B-doping effect. Especially, in order to optimize B-doped AC, amounts of precursors are regulated. The optimized B-doped AC electrode shows a good charge-transfer process and superior electrochemical performance, including high specific capacity of 157.4 mAh g^-1 at current density of 0.5 A g^-1, high-rate performance with 66.6 mAh g^-1 at a current density of 10 A g^-1, and remarkable, ultrafast cycling stability (90.7 % after 10,000 cycles at a current density of 5 A g^-1). The superior energy storage performance is attributed to the B-doping effect, which leads to an excellent charge-transfer process of the AC cathode. Thus, our strategy can provide a rational design for ultrafast cycling stability of next-generation supercapacitors in the near future.

GRP 연성관의 관강성 예측

이영근,김선희,박준석,윤순종,Lee, Young-Geun,Kim, Sun-Hee,Park, Joon-Seok,Yoon, Soon-Jong 한국복합신소재구조학회 2011 복합신소재구조학회논문집 Vol.2 No.3

In this paper, we present the load-deflection behavior of GRP pipes. GRP buried pipes are widely used in construction in the advantage of their superior mechanical and physical characteristics such as high chemical resistance, high corrosion resistance, right weight, smooth surface of the pipe, and cost effectiveness from soil-structure interaction. To design flexible pipes to be buried underground, it should be based on the ASTM D2412(2010). When applying ASTM D 2412(2010) to the design, pipe stiffness(PS) must be predetermined by the parallel-plate test which requires tedious and laborious working process. To overcome such problems, the finite element simulations for finding the load-deflection behavior of the GRP flexible pipes is installed at UTM testing machine. In the finite element simulations, basic data, such as the modulus of elasticity of the material and cross-sectional dimension, is used. From the investigation, we found that the difference between experimental result and analytical prediction is less than 15% when the pipe deflected 3% and 5% of its vertical diameter although the pipe material is not uniform across the cross-section. 이 연구에서 GRP 관의 하중-처짐 거동을 조사, 보고하였다. 지중매성 GRP관은 높은 내화학성, 높은 부식저항성, 경량성, 관표면의 매끄러움, 지반-관의 상호작용 고려에 따른 경제성 등의 탁원한 역학적, 물리적 특성들로 인해 건설현장에서 광범위하게 사용되고 있다. 지중에 매설되는 연성관을 설계하기 위해서는 ASTM D 2412 (2010)에 따라야 한다. ASTM D 2412 (2010)에 따라 설계할 경우, 관의 원강성 (PS)을 편평시험에 따라 먼저 결정해야 하는데, 이 시험이 귀찮고 노동력을 필요로 한다. 이러한 문제를 해결하기 위해 UTM에 설치된 형태의 GRP관의 하중-처짐 거동을 유한요소법에 따라 모사하였으며, 유한요소법에 의한 모사에는 재료의 탄성계수와 단면의 기하학적 치수 등 기초적인 자료를 사용하였다. 이와 같은 연구로부터, 관재료가 관의 단면내에서 비교적 일정하지 않음에도 불구하고 수직방향의 관변형이 3%와 5%가 발생할 경우, 편평시험과 수치해석적 연구 결과가 15%이내의 차이로 하중의 예측이 가능함을 알 수 있었다.

부유식 태양광 에너지 발전시설의 수정설계

이영근,주형중,남정훈,윤순종,Lee, Young-Geun,Joo, Hyung-Joong,Nam, Jeong-Hun,Yoon, Soon-Jong 한국복합신소재구조학회 2010 복합신소재구조학회논문집 Vol.1 No.4

We had designed and constructed floating type photovoltaic energy generation system. In this paper, we present the result of investigations pertaining to the development of links between unit modules of the floating type photovoltaic energy generation system. The link system installed between the unit modules is made of pultruded FRP, tire, and polyethilene synthetic fiber rope. The link system is analized by the finite element method. The floating type photovoltaic energy generation system consisted of unit modules connected by link system is installed successfully at sea site. In addition, we present the modified design of the floating type photovoltaic energy generation system based on the proto type system.

수질관리 : 영산호 수체 오염도 및 퇴적물 유해성 조사

이영근 ( Young Geun Lee ),기백수 ( Baek Su Ki ),윤인호 ( In Ho Yoon ),황경섭 ( Kyung Seop Hwang ),이영준 ( Young Joon Lee ),김준하 ( Joon Ha Kim ) 대한상하수도학회 2005 공동추계 학술발표회 논문집 Vol.2005 No.-