http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kim, Jakyung,Kim, Hyunho,Sohn, Young hoon,Chang, Daejun,Seo, Yutaek,Kang, Seong-Pil Elsevier 2017 Journal of petroleum science & engineering Vol.154 No.-
<P><B>Abstract</B></P> <P>Methane gas produced from marine hydrate deposits will flow together with dissociated water in two phases, and the risk of hydrate reformation must be managed. This study used the OLGA multiphase flow simulation software to simulate methane transportation with dissociated water through a vertical 2160m pipeline in order to determine the amount of monoethylene glycol (MEG) as a thermodynamic hydrate inhibitor. When the hydrate saturation ratio in hydrate deposits varies, a large amount of MEG becomes inevitable. Moreover, when undesired water breakthrough occurs, the MEG concentration would decrease to where hydrates may re-form before responding in the offshore platform. A risk management strategy for hydrate reformation is investigated by adopting under-inhibition with MEG and the addition of PVCap as a kinetic hydrate inhibitor (KHI). The experimental results in high pressure autoclave showed that PVCap exhibited a limited performance in delaying the hydrate formation in a high subcooling condition. Considering the vertical flowline of 2160m, the delay time was not sufficient to prevent the hydrate re-formation in the transport pipeline. Complete prevention of hydrate re-formation can be avoided with 35wt% MEG concentration, however decreasing the MEG concentration to 20wt% was also feasible in order to avoid hydrate formation since it was not observed for more than 960min. In the presence of 0.1wt% of PVCap and 10wt% MEG, the hydrate delay time was of about 311.5min. This delay time is 76% longer than the residence time of methane and water mixture in the transport pipeline, thus this synergistic inhibition can significantly reduce the injection rate of MEG while preventing hydrate formation. This is the first work suggesting a risk management strategy for hydrate reformation in hydrate production system, and thus will provide insights to develop advanced hydrate production technologies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multiphase flow simulation was performed for methane hydrate production. </LI> <LI> Hydrate reformation risk was managed by under-inhibition with MEG. </LI> <LI> Synergistic inhibition with MEG and KHI increased onset time significantly. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
김현경(Hyungyung Kim),오영섭(Youngsup Oh),송대준(Daejun Song),오승택(Sengtaek Oh),김동학(Donghak Kim),이동열(Dongyul Lee) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
A new point of view in vehicle bumper frame is proposed by Contacted 2 Pipes BUMPER STRUCTURE, which is a new development method based on the principle of hot-stamping, structural design, method of TRIZ and evaluations. As a result of the application of new bumper frame, this paper classifies Increased of strength to 1.8GPa, Shapes of Cold Coiled Thin Pipe, optimized structural design, and enhanced performance of RCAR, Towing and Shipping.
차세대중형위성 4호 전자광학부체계 카메라제어전원장치(CCPU) 공학인증모델(EQM)과 비행모델(FM)의 유닛 수준 개발과 부체계 수준 개발
윤지호(JiHo Yun),김상일(Sang-il Kim),안석현(Seokhyen An),김현구(Hyungu Kim),홍원표(Won-Pyo Hong),이경우(KyungWoo Lee),김종운(Jongun Kim),공종필(JongPil Kong),이도경(DoKyoung Lee),정대준(DaeJun Jung),이상규(SangGyu Lee) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.11
이강미(Kangmi Lee),김성진(Sungjin Kim),김대준(Daejun kim),김재호(Jaeho Kim) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.10
최근 국내 철도시스템에서도 ‘원격’, ‘무선’, ‘무인’과 같은 승객/운영자 편의 기능이 차량의 필수 기능사양으로 요구되어지고 있다. 무선기반 완전 무인 열차제어시스템, 실시간 차량상태 모니터링 기술 등이 그 예이다. 현재까지는 기존 차량에 운영유지보수 효율성을 위하여, 유무선 통신기술을 적용한 응용기술 관점의 융합기술이 개발되었지만, 보다 진화된 철도차량개발을 위해서는 차량 자체가 지능화 되어야 한다. 본 논문에서는 전장기술 관점에서 지능형 철도차량의 국내외 현황, 필요성 그리고 기술개발 방향에 대하여 기술하고자 한다. In recent years the domestic rail passenger system / operator-friendly features such as "remote", "radio", "unattended" needs are becoming an essential functional specifications of the vehicle. And wireless-based train control system completely unattended, real-time vehicle status monitoring technology is an example. Until now, in order to enhance maintain efficiency in existing vehicles, the development of ICT convergence technology have applied technology perspective applied for wired and wireless communications technology, but the vehicle itself should be intelligent in order to develop a more advanced rail car. In this paper, we describe about the domestic and international status, and the need for technology development direction of railway vehicles on the vehicle electronics technology perspective.
Kim, Juwon,Noh, Yeelyong,Chang, Daejun Elsevier 2018 APPLIED ENERGY Vol.212 No.-
<P><B>Abstract</B></P> <P>This study proposed a storage-generation system for a distributed-energy generation using liquid air combined with liquefied natural gas (LNG). The system comprised three main sites: the renewable-electricity sources (RESs), liquid-air energy storage (LAES), and natural-gas combustion. The low-priced off-peak electricity generated by the RESs was supplied to the LAES. The supplied electricity and previously stored cold energies liquefied the air. At the on-peak time, the liquid air and LNG were pressurized, re-gasified, and burnt immediately after mixing to generate the high-priced electricity while their cold energy was stored in thermal media. The proposed system was evaluated in terms of the thermodynamic, environmental, and economic performances. Its round-trip and storage efficiencies were 64.2% and 73.4%, respectively. The exergy efficiency of the storage-site, the generation-site, and the system was 70.2%, 75.1%, and 62.1%, respectively. The levelized cost of energy (LCOE) ranged from 142.5 to 190.0 $/MWh depending on the sizes and the storage time. The proposed system was compared to the diabatic compressed air-energy storage (CAES) systems and the adiabatic LAES system. The sensitivity analyses compared the systems for the fixed power output and storage time, and for the option to use natural gas. The proposed system showed better storage and round-trip efficiencies than those of comparison systems. Its LCOE was competitive with those of the compared systems except for the under-ground CAES system. The proposed system was an economic and viable option considering the geographical limitations and the environment impacts of the CAES system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A storage-generation system using liquid air and liquefied natural gas is proposed. </LI> <LI> Round-trip and storage efficiencies of the system are 64.2% and 73.4% respectively. </LI> <LI> Exergy efficiencies of the storage and the system are 70.2% and 62.1% respectively. </LI> <LI> LCOE ranges from 142.5 to 190.0 $/MWh, depending on the sizes and the storage time. </LI> <LI> The proposed system is an economic option without geographical limitations. </LI> </UL> </P>
Investigation of amorphous material with ice for cold thermal storage
Kim, Jhongkwon,Park, Hyunjun,Bae, Junhyuk,Jeong, Sangkwon,Chang, Daejun The Korea Institute of Applied Superconductivity a 2019 한국초전도저온공학회논문지 Vol.21 No.1
This study investigates mixtures of water and cryoprotectant agents (CPAs) to store high-grade cold energy. Although water is an ideal material for a cold thermal storage (CTS) due to its high specific heat, undesirable volume expansion may cause structural stresses during freezing. The volume expansion can be alleviated by adding the CPAs to water. However, the CPA aqueous solutions not only have different thermal properties but also transit to amorphous state different from pure water. Therefore, these characteristics should be considered when using them as material of the CTS. In experiments, glycerol and dimethyl sulfoxide (DMSO) are selected as the candidate CPA. The volume expansion of the solution is measured by an in-situ strain gauge in low temperature region. The specific heat capacity of the solution is also measured by differential scanning calorimetry (DSC). Both the amount of volume expansion and the specific heat capacity of the CPA aqueous solution decrease in the case of higher concentration of CPA. These characteristics should be contemplated to select optimal aqueous solution for CTS for liquid air energy storage system (LAES). The CPA solutions have advantages of having wide temperature range to utilize the latent heat of water and higher sensible heat of the CPA. The CPA solutions which can satisfy the allowable stress of the structure are determined. Consequently, among the CPA solutions investigated, DMSO 20% w/w solution is the most suitable for the CTS.