• 제목/요약/키워드: Hi-carbon

검색결과 105건 처리시간 0.018초

고장력 인장봉으로 보강된 RC 보의 휨 거동에 관한 실험적 연구(3) (An Experimental Study on Flexural Behavior of RC Beams Strengthened with Hi-Strength Bars(3))

  • 신경재;김윤정;문정호
    • 콘크리트학회논문집
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    • 제19권3호
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    • pp.351-358
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    • 2007
  • 현재 상용되고 있는 강판 보강법이나 탄소섬유 시트 부착 보강법과는 달리, 고장력 인장봉을 이용한 외부 비부착 방식의 보강법은 설치가 간단하고 시공 시간이 짧은 등의 장점이 있다. 또한 외부 비부착 보강법은 콘크리트 표면처리가 필요 없고 에폭시 등의 접착제를 사용하지 않아 환경에 미치는 영향도 적다. 지난 연구에 이어 본 연구에서는 보강된 RC보에 관한 총 9개의 실대형 시험체를 변수별로 제작하여 여러 변수가 실제 구조물에 미치는 영향을 검토하였다. 시험체의 주요 변수는 보강재의 크기와 전단 보강근의 간격, 지지 조건이다. 본 논문에서는 보강된 RC 보의 구조적 거동을 무보강 시험체와 비교하여 기술하였다. 실험 결과 고장력 인장봉으로 보강된 RC보는 무보강 시험체와 비교하여 강도와 휨 성능에서 탁월한 효과를 나타내었으며 전단 보강근이 과소 배근된 시험체에서도 고장력 인장봉에 의한 전단 내력 효과를 보였다.

유리기판 위에 성장된 카본나노튜브를 이용한 고휘도 램프 특성 (Development of flat type back-lamp using carbon nano tubes grown on glass substrate)

  • 이양두;이덕중;박정훈;유재은;이윤희;장진;주병권
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 춘계학술대회 논문집 디스플레이 광소자 분야
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    • pp.89-92
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    • 2002
  • Carbon nano tubes(CNTs) have been reported as field emission source because has a sharp tip, a high aspect tip, high chemical stability, high mechanical strength and low work function properties. In this study, we fabricated successfully the back-lamp of the I-inch flat type using CNTs, which was grown directly on cathode substrate of sodalime glass at low temperature. The brightness of CNT back-lamp is measured to $14 Kcd/m^{2}$ at $2000V_{dc}$ in spacing of $500{\mu}m$. And, the emission properties of packaged CNT back-lamp was analyzed as function of applying voltage and times.

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Hot isostatic pressure을 이용한 CN nanofiber의 구조 및 전계방출 특성 (Structure and field emission properties of carbon-nitrogen (CN) nanofibers obtained by hot isostatic pressure)

  • 이양두;;;;남산;이윤희;주병권
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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    • pp.84-87
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    • 2003
  • Carbon-nitrogen (CN) nanofibers have been produced using a water cooled hot isostatic pressure (HIP) apparatus. The CN nanofibers were grown in random with the diameter of about 100-150nm and length over $10{\mu}m$. Emission properties of CN nanofibers were investigated for spacing, between anode and cathode, variation. Then turn-on fields about $1.4V/{\mu}m$. The time reliability and light emission test were carried out for above 100 hours. We suggest that CN nanofibers can be possibly applied to high brightness flat lamp because of low turn-on field and time reliability.

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탄소섬유강화플라스틱(CFRP)의 적층 배향각에 따른 드릴링 가공 특성 고찰 (Investigation Into the Drilling Characteristics of Carbon Fiber Reinforced Plastic (CFRP) with Variation of the Stacking Sequence Angle)

  • 김태영;김호석;신형곤
    • 한국생산제조학회지
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    • 제23권3호
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    • pp.250-258
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    • 2014
  • Due to recent industrial growth and development, there has been a high demand for light and highly durable materials. Therefore, a variety of new materials has been developed. These new materials include carbon fiber reinforced plastic (CFRP or CRP), which is a wear-, fatigue-, heat-, and corrosion-resistant material. Because of its advantageous properties, CFRP is widely used in diverse fields including sporting goods, electronic parts, and medical supplies, as well as aerospace, automobile, and ship materials. However, this new material has several problems, such as delamination around the inlet and outlet holes at drilling, fiber separation, and tearing on the drilled surface. Moreover, drill chips having a fine particulate shape are harmful to the work environment and engineers' health. In fact, they deeply penetrate into machine tools, causing the reduction of lifespan and performance degradation. In this study, CFRP woven and unidirectional prepregs were formed at $45^{\circ}$ and $90^{\circ}$, respectively, in terms of orientation angle. Using a high-speed steel drill and a TiAIN-coated drill, the two materials were tested in three categories: cutting force with respect to RPM and feed speed; shape changes around the input and outlet holes; and the shape of drill chips.

집중 강우시 남한강 내 용존 유기물의 성상 변화 (Changes in Dissolved Organic Matter Composition in the Namhan River during a Heavy Rain Event)

  • 오세진;우성호;허진;정명숙;신현상
    • 한국물환경학회지
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    • 제25권5호
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    • pp.697-703
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    • 2009
  • In this study, changes in the composition of dissolved organic carbon (DOC) were investigated using water samples collected at a downstream site of the Namhan River near the Lake Paldang ($N37^{\circ}24^{\prime}05.33^{{\prime}{\prime}}E127^{\circ}32^{\prime}25.01^{{\prime}{\prime}}$) during a heavy rain event from July 23 to July 28, 2008. The DOC concentrations varied from 1.68 to 3.18 mg/L with the maxium value at a peak of the river water level. Each DOC sample was fractionated into three compositions including hydrophilic (Hi), hydrophobic acid (HoA) and hydrophobic neutral (HoN) fractions. The results showed that HoA was most abundant fractions, constituting 47.2~56.5% of DOC. Refractory dissolved organic carbon (R-DOC) contents were also determined by measuring the DOC concentration after 28-day dark incubation of the samples. R-DOC content was in the range from 83 to 99% of DOC and it was significantly correlated with HoA contents (r = 0.91, p<0.005), while it did not exhibit such a good correlation with the fractions of Hi and HoN (p>0.02). Our results suggest that the HoA, which is associated with humic substances, may be a major composition of refractory organic matters in rivers during storm events.

Non-energy Use and $CO_2$ Emissions: NEAT Results for Korea

  • Park, Hi-chun
    • 에너지공학
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    • 제11권1호
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    • pp.34-46
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    • 2002
  • Carbon accounting is a key issue in the discussions on global warming/CO$_2$mitigation. This paper applies both the IPCC Approach and the NEAT (Non-Energy use Emission Accounting Tables) model, a bottom-up approach, to estimate the potential CO$_2$ emissions (carbon storage) originating from the non-energy use as to assess the actual CO$_2$ emissions (carbon release) from the use of fossil fuels in Korea. The current Korean carbon accounting seems to overestimate the potential CO$_2$ emissions and with it to underestimate the actual CO$_2$ emissions. The estimation shows that the potential CO$_2$ emissions calculated according to the IPCC Approach are lower than those calculated using the NEAT model. This is because the IPCC default storage fraction for naphtha seems to be low for the Korean petrochemical production structure, on the one hand and because the IPCC Approach does not consider the trade with short life petrochemical products, on the other hand. This paper shows that a bottom-up approach like the NEAT model can contribute to overcome some of limitations of the IPCC guidelines, especially by considering the international trade with short life petrochemical products and by estimating the storage fractions of fossil fuels used as feedstocks for the country in consideration. This paper emphasizes the importance of accurate energy statistics for carbon accounting.

복합섬유(複合纖維) 횡보강(橫補强)콘크리트의 강도(强度) 특성(特性)에 관한 연구(硏究) (The Strength Characteristics of Concrete Confined with Composite Fiber)

  • 장정수;저성찬;강충렬
    • 한국구조물진단유지관리공학회 논문집
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    • 제5권2호
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    • pp.93-102
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    • 2001
  • The objective of this experimental study is to evaluate the strengthening effects of concrete compression confined with Epoxy-boned compound fiber sheets. An analytical model is proposed to construct a stress-strain relationship for confined concrete. Test results are summarized as followed. While non-FRP lateral confinement specimens appeared sudden failure after shell concrete was torn off, specimens confined laterally with FRP were showed that their failure. Specially, Glass fiber lateral confined specimens occurred obviously increase ductility ability. Hence, concrete specimen with lateral confinement by Hi-carborn and Aramide. Glass fiber simultaneously can be increased in not only strength but also a lot of ductility ability.

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HI 농축에 대한 전기투석 셀의 성능 및 운전한계조건 연구 (A Study on the Performance and Operation Limit of Electrodialysis Cell for HI Concentration)

  • 이병우;정성욱;조원철;강경수;박주식;배기광;김영호;김창희
    • 한국수소및신에너지학회논문집
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    • 제22권6호
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    • pp.749-758
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    • 2011
  • The present work explores the performance and operation limit of electrodialysis cell for HI concentration in sulfur iodine thermochemical hydrogen production process, For this purpose, the electrodialysis cell was assembled with Nafion 117 as a PEM membrane and two activated carbon papers as the electrodes. HIx solution was prepared with composition of HI: $I_2$: $H_2O$ = 1: 0.5~2.5: 5.2 in molar ratio. The cell and its peripheral apparatus were placed in the specially designed convective oven in order to uniformly maintain the operation temperature. As operation temperature increased, the amount of water transport from anode to cathode increased, thus reducing HI molarity in catholyte. Meanwhile, the current efficiency was constant as about 90 %, irrespective of temperature change. The cell voltage increased with initial $I_2$ mole ratio as well as anolyte to catholyte mole ratio. Moreover the cell voltage overshot took place within 10 h cell operation, which is due to the $I_2$ precipitation inside the cell. From the analysis of $I_2$ mole ratio in the anolyte, it is noted that operation limit (in $I_2$ mole ratio) of the electrodialysis cell, arising from was measured to be 3.2, which is much lower than bulk solubility limit of 4.7.

XAD 수지분획과 생분해 실험에 의한 기원별 용존유기물질 특성 연구 (Study on the Characteristics of Dissolved Organic Matters from Diverse Sources by XAD Resin Fractiontion and Microbial Incubation Experiments)

  • 오세진;최찬규;허진;정명숙;신현상
    • 한국물환경학회지
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    • 제26권6호
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    • pp.976-985
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    • 2010
  • In this study, characteristics of dissolved organic matter (DOM) from Lake Paldang and seven other DOM sources (lake plankton, plants, soil, composite, treated sewage) were studied using XAD resin fractionation and 28-day microbial incubation experiment. Distribution patterns of DOM-fractions, which include hydrophilic acids (HiA), hydrophilic bases (HiB), hydrophilic neutrals (HiN), hydrophobic acids (HoA), hydrophobic neutrals (HoN) and the extent of DOM biodegradation (i.e., biodegradability) were different depending on the origins of the DOM samples. The DOM distribution pattern and the biodegradability were found to be effective for distinguishing the different DOM sources. The biodegradability (%) had negative correlations with the content (%) of hydrophobic fractions (Ho) and specific UV absorbance of DOM, which indicate that the Ho fractions contain more aromatic carbon structures and relatively stable during biodegradation, irrespective of the sources. To gain additional insight into the microbial transformation of the DOM, we also investigated the changes in the fraction's distribution for plankton, leaf litter and composite samples after the incubation. The results showed that biodegradation of hydrophilic fraction (Hi) causes an increase in the proportion of Ho (HoA, HoN), while biodegradation of HoA increases the HoN production.

초정밀 스프레이 방법을 이용한 단일벽 탄소나노튜브 pH센서 개발 (Development of single walled-carbon nanotubes based pH sensor using ultra-precision spray method)

  • 권재홍;이경수;이윤희;주병권
    • 센서학회지
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    • 제15권2호
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    • pp.127-133
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    • 2006
  • Recent studies demonstrated the ability of carbon nanotube (CNT) to promote electron transfer reactions of important compounds and to impart higher stability onto electrochemical sensors. CNT-based sensors measured by hydroxyl radical concentration or pH value suggest great promise for biosensors. This paper describes a new method for fabricating a very simple and inexpensive pH sensor compose of single walled-carbon nanotubes (SW-CNTs) using an ultra-precision spray. CNT-based sensor shows pH sensitivity in buffer solution at different pH range. Our experimental results show the sensor responses to pH buffer solution and the conductance of depends on the pH values. These results support application possibility of SW-CNTs based pH sensor for mass production.