• 한국구조물진단유지관리공학회 논문집
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• 제8권3호
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• pp.207-215
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• 2004

본 연구에서는 손상된 기존 철근콘크리트 보에 대한 보강공법 중의 하나인 외부 프리스트레싱 보강공법과 긴장재로 사용되는 강연선 또는 CFRP(Carbon Fiber Reinforced Plastic)판을 적용하여 그 보강효과를 파악하기 위한 구조실험을 수행하였다. 구조실험 결과를 분석하여, 본 연구에서 사용한 재료의 경우에 어느 정도의 강성증가 효과와 연성증진 효과를 발휘하는가를 파악하였다. 그 결과, 강연선과 CFRP로 보강한 각각의 경우에 무보강 시험체를 기준으로 57%와 75%의 강도증진 효과를 나타내었다.

• Carbon letters
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• 제26권
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• pp.74-80
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• 2018

The South Korean Ministry of the Environment has revised the laws relating to the management of interior air quality for multiple use facilities, and recommends maintaining carbon dioxide ($CO_2$) concentration in passenger vehicles below 1000 ppm during operation in urban areas of large cities. However, the interior $CO_2$ concentration of passenger vehicles can rapidly increase and exceed 5000 ppm within 30 min, as observed when two passengers are traveling in urban areas of the South Korean city of Jeonju with the air conditioner blower turned off and the actuator mode set to internal circulation mode. With four passengers, $CO_2$ concentration can reach up to 6000 ppm within 10 min. To counter this, when the actuator is set to external mode, $CO_2$ concentration can be maintained below 1000 ppm, even after a long period of running time. As part of the air conditioning system, alkali-treated activated carbon fiber filters are considered to be far superior to the commercial non-woven filters or combination filters currently commonly in use.

• 한국전기전자재료학회논문지
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• 제14권7호
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• pp.578-583
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• 2001

The bushing for high voltage and large and power should endure weight of itself and force of pushing from contact with circuit breaker. Like this, epoxy mold bushing has to be strong without fault. However, the external circumstances and internal factors was caused by partial discharge, flashover and dielectric breakdown. Therefore, to remove external factor of defect and to prevent the internal cracks and cavity generated from the contraction on interface of Cu-Epoxy, we should form semi-conductive layer on Cu bar by carbon. Then, the PD properties and the insulation qualities of epoxy mold type bushing was able to improved by roles of cushions for the direction of diameter and by effects fo natural sliding like as separated from conductor for the direction of length. So, in this work, we could prove the method of semi-conductive layer in making the long conductor.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.763-768
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• 2000

The purpose of this paper is to predict the flexural strengthening of reinforced concrete beams by the external bonding of carbon fiber reinforced plate(CFRP) to the tension face of the beam. Used computational equation is derived by relation of stress an strain. This equation is applied to four-nondamage beam and tow-preloading beam. Six scale beams were tested to evaluate the strength enhancement provided by the CFRP. And describes the strength enhancement provided to the flexural capacity of reinforced concrete beam by the external bonding of CFRP. An inelastic section analysis procedure was developed that accurately predicts the load displacement response of the retrofitted beams.

• KSBB Journal
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• 제23권6호
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• pp.535-540
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• 2008

In this study, the effects of several factors such as initial nitrate concentration, C/N ratio, biomass amount and external carbon source on denitrification process were investigated using synthetic wastewater and sludge obtained from wastewater treatment facility. As a result, the condition of lower initial nitrate concentration was increased to the removal rate of nitrate than that of high concentration. The increases of C/N ratio and initial biomass amount were linearly enhanced the removal rate. The use of ethanol as external carbon source was shown the highest removal yield than that of others.

• 대한의용생체공학회:의공학회지
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• 제45권2호
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• pp.57-65
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• 2024

Recently, several studies have been conducted to lower the cost of transport of human by adding external joint stiffness elements. However, it has not been clearly elucidated whether adaptation time is required for human subjects to adapt to the added external joint stiffness. In this study, carbon plates in the form of shoe midsoles were added to the metatarsophalangeal joint, and the lower limb joint torque and mechanical energy consumption were compared before and after a total of 5 sessions (2.5 weeks) of running. A total of 11 young healthy participants exhibited higher elastic energy storage in carbon plates in the fifth session compared to the first session, and lower power in the ankle joint. This suggests that a single training session may be insufficient to validate the efficiency effect of added joint stiffness, and the human body seems to increase the elastic energy stored in the assistive joint stiffness and its reutilization.

• 한국미생물·생명공학회지
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• 제26권2호
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• pp.96-101
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• 1998

여러 가지 외부 탄소원(acetic acid, glucose, methanol, molasses)으로 활성 슬러지를 이용하여 탈질 효과를 살펴보았다. 질산성 질소와 아질산성 질소를 질소원으로 하는 혐기성 슬러지의 회분식 배양을 통해 탈질속도, COD 소비, 탈질율을 조사해 본 결과 molasses는 탈질속도나 COD 소비에서 glucose와 비슷하고 acetic acid나 methanol보다 높았으나, 탈질 효율에 있어서는 질산성 질소나 아질산성 질소배지에서 30-40%가 암모니아로 축적되어 탈질 효율이 떨어졌다. 이러한 현상은 molasses와 glucose를 탄소원으로 이용한 경우 발효에 의해 pH저하를 초래하고 이로 인해 탈질 효율이 감소되는 것으로 생각된다. 따라서 초기 pH를 조절하고 외부 탄소원은 molasses를 이용, 탈질 효과를 조사한 결과 pH 8일 때 암모니아의 축적은 거의 없었으며 탈질 속도에 있어서도 acetic acid의 경우보다 12시간정도 빠른 24시간 안에 99% 이상 탈질 효율이 증가함을 알 수 있었다.

• 한국환경과학회지
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• 제23권1호
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• pp.53-60
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• 2014

Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time ($t_{0.05}$), saturation time ($t_{0.95}$), length of mass transfer zone ($L_{MTZ}$), adsorptive capacity (W), and adsorption rate constant ($K_a$) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer $L_{MTZ}$ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.

• Advances in nano research
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• 제6권4호
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• pp.299-321
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• 2018

A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelectric truncated conical shell. The core is a multiphase nanocomposite reinforced by carbon nanotubes (CNTs) and carbon fibers. The top and bottom face sheets are piezoelectric subjected to 3D electric field and external voltage. The Halpin-Tsai model is used for obtaining the effective moisture and temperature dependent material properties of the core. The proposed layerwise theory is based on Mindlin's first-order shear deformation theory in each layer and results for a laminated truncated conical shell with three layers considering the continuity boundary condition. Applying energy method, the coupled motion equations are derived and analyzed using differential quadrature method (DQM) for different boundary conditions. The influences of some parameters such as boundary conditions, CNTs weight percent, cone semi vertex angle, geometrical parameters, moisture and temperature changes and external voltage are investigated on the buckling load of the smart structure. The results show that enhancing the CNTs weight percent, the buckling load increases. Furthermore, increasing the moisture and temperature changes decreases the buckling load.

• Korean Chemical Engineering Research
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• 제60권4호
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• pp.478-485
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• 2022

외부사업을 통해 발행받은 인증실적을 배출권 거래제 할당 대상 업체에게 판매하고 할당 대상업체는 구매한 외부사업 인증실적을 상쇄 배출권으로 바꾸어 할당량을 확보할 수 있다. 본 방법론은 기존 기름보일러를(유종별) 사용하던 화석연료를 상대적으로 탄소 함량이 적은 프로판가스를 사용하는 보일러로 교체하였을 때 유종별 이산화탄소 배출 감축분을 인정받아 온실가스 감축을 하지 못해 배출허용량을 넘긴 대기업의 부족된 할당량으로 보충하기 위한 초기 분석으로 탄소감축 배출량과 배출권 거래 금액을 산출하였다.