• 한국군사과학기술학회지
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• 제10권1호
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• pp.33-43
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• 2007

Using the more common conventional chordwise aerodynamic approach, flapping a flat plate wing with zero degree chordwise pitch angle of attack and no relative wind should not produce lift. However, in hover, with no forward relative velocity and zero degree chordwise pitch angle of attack, flapping flat plate wings does in fact produce lift. In the experiments peformed for this paper, the flapping motion is considered pure(downstroke and upstroke) with no flapping stroke plane inclination angle. No changes in chordwise pitch angle are made. The total force is measured using a force transducer and the net aerodynamic force is determined from this measured total force by subtracting the experimentally determined inertial contribution. These experiments were repeated at various flapping frequencies and for various wing planform sizes for flat plate wings. The trends in the aerodynamic lift variation found using a force transducer have nearly identical shape for various flapping frequencies and wing planform sizes.

• 한국초지조사료학회지
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• 제17권1호
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• pp.35-42
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• 1997

Many farmers apply cattle slurry on grassland, often in excess of crop N requirements, resulting in groundwater contamination. Our research objective was the development of grassland management systems that reduce undesirable sideeffects on other compartment of the ecosystem. Field experiment was conducted during 1991~1993 on sandy loam soil at AllgZiu south western Germany. Different sets of conditions were tested such as : zero fertilization, reduced sluny application$(l20kg N ha^{-1}yr^{-1})$, intensive sluny application(conventional sluny application, $240kg N ha^{-1}yr^{-1}$). The plots of the reduced slurry application had no significant effect on dry matter yields, digestible dry matter and net energy of herbage. Dry matter yield of zero fertilization was significantly lower than that of usual slurry application, however the content of Ca and Mg in herbage tended to increase. We conclude that reduced sluny application can be applied on grassland without adverse effects on dry matter production and quality of herbage.

• Journal of Pharmaceutical Investigation
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• 제5권2호
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• pp.57-62
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• 1975

It was many differances to evaluate of the effect of excipients on colour fading in FD & C Yellow No.5 by use Tintometer and nearly is not effective in FD & C Red No. 2. When we observed colour fading in suger coating formulations by tintometer, FD & C Red No.2 was appeared to follow zero order reaction and FD & C Yellow No. 5 was not follow zero order reaction or first order reaction. Also, we could know the tendency of colour fading by visible spectrum, but it was net suitable method for this experiment more than by tintometer. The relative colour fading effect of the surfactants(Polysorbate) was as follows: Tween 60> Tween 80> Tween 20. In addition to, Benzalkonium chloride was reacted with FD & C Yellow No.5, so the stronger colour was appeared. On the other hand, the weaker colour was appeared in FD & C Red No.2. While, the sunscreening agents was not almost effective in colour fading of FD & Yellow No. 5 and FD & C Red No. 2.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2133-2150
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• 2021

In this work, Esfahan light water subcritical reactor (ELWSCR) is analysed using experimental and theoretical diagnostic methods. Important neutronic parameters of the system such as prompt neutron lifetime, delayed neutron fraction, prompt neutron decay constant, negative reactivity of the core, fuel and moderator temperature coefficient of reactivity, and overall and local void coefficient of reactivity are estimated. Also, neutron flux distribution, reflector saving, water level effect, and lattice pitch of the core including operating point of the facility are studied in details. Theoretical results are calculated by MCNPX and measurements are performed utilizing zero power reactor noise method. Detailed descriptions of the results are explained in the text.

• 정보보호학회논문지
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• 제22권3호
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• pp.417-425
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• 2012

2010년, Sebe 등은 원격 투표에 사용할 수 있는, 가벼우면서도 효율적인 믹스넷 방식을 제안하였다. 이 방식은 암호학적 해쉬연산 만을 이용하기 때문에 기존 방식처럼 복잡한 영지식증명(zero-knowledge proofs)이 필요없이 간단하면서도 믹스넷의 동작을 효율적으로 증명할 수 있는 장점이 있다. 본 논문에서는 Sebe 등이 이용한 가정 사항을 그대로 유지하면서 보다 효율적인 믹스넷을 제안한다.

• 한국산업융합학회 논문집
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• 제27권2_1호
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• pp.269-276
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• 2024

Many countries across the world are making efforts beyond reducing CO₂ levels and declaring 'net zero,' which aims to cut greenhouse gas emissions to zero by not emitting any carbon or capturing carbon, by 2050. Hydrogen is considered a key energy source to achieve carbon neutrality goals. Korean companies are also interested in building overseas green ammonia production plants and importing hydrogen into Korea in the form of ammonia. Green hydrogen production uses renewable energy sources such as solar and wind power, but the variability of power production poses challenges in plant design. Therefore, optimization of the configuration of a green ammonia production plant using renewable energy is expected to contribute as basic information for securing the economic feasibility of green ammonia production.

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.648-653
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• 2018

Elimination of soluble boron from reactor design eliminates boron-induced reactivity accidents and leads to a more negative moderator temperature coefficient. However, a large negative moderator temperature coefficient can lead to large reactivity feedback that could allow the reactor to return to power when it cools down from hot full power to cold zero power. In soluble boron-free small modular reactor (SMR) design, only control rods are available to control such rapid core transient. The purpose of this study is to investigate whether an SMR would have enough control rod worth to compensate for large reactivity feedback. The investigation begins with classification of reactivity and completes an analysis of the reactivity balance in each reactor state for the SMR model. The control rod worth requirement obtained from the reactivity balance is a minimum control rod worth to maintain the reactor critical during the whole cycle. The minimum available rod worth must be larger than the control rod worth requirement to manipulate the reactor safely in each reactor state. It is found that the SMR does have enough control rod worth available during rapid transient to maintain the SMR at subcritical below k-effectives of 0.99 for both hot zero power and cold zero power.

• 교육녹색환경연구
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• 제21권2호
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• pp.25-35
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• 2022

'기후 위기에 대처하기 위한 탄소 중립 및 녹색 성장에 관한 기본법' 이 제정됨에 따라, 탄소중립 달성을 위한 다양한 부문별 계획들(NDC)이 시행되고 있다. 학교시설은 '제로에너지건축물 인증'의 의무대상 건축물이며, 공공기관 건축물 중 가장 높은 비중을 차지하는 건물로, 탄소중립 시나리오의 건물부문에서 주요한 역할을 한다. 본 연구는 이러한 학교시설의 건물에너지관리시스템 보급 활성화 및 효율적인 운영관리를 위한 기초자료 제공을 위하여, 최근 에너지사용 동향과 제로에너지수준을 다양한 방면에서 분석하였으며, 학교시설에 적용된 BEMS의 효과 및 사용자 의견을 조사하였다.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3359-3366
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• 2023

In this study, a spiking cortical model (SCM) based n-g discrimination method is proposed. The SCM-based algorithm is compared with three other methods, namely: (i) the pulse-coupled neural network (PCNN), (ii) the charge comparison, and (iii) the zero-crossing. The objective evaluation criteria used for the comparison are the FoM-value and the time consumption of discrimination. Experimental results demonstrated that our proposed method outperforms the other methods significantly with the highest FoM-value. Specifically, the proposed method exhibits a 34.81% improvement compared with the PCNN, a 50.29% improvement compared with the charge comparison, and a 110.02% improvement compared with the zero-crossing. Additionally, the proposed method features the second-fastest discrimination time, where it is 75.67% faster than the PCNN, 70.65% faster than the charge comparison and 38.4% slower than the zero-crossing. Our study also discusses the role and change pattern of each parameter of the SCM to guide the selection process. It concludes that the SCM's outstanding ability to recognize the dynamic information in the pulse signal, improved accuracy when compared to the PCNN, and better computational complexity enables the SCM to exhibit excellent n-γ discrimination performance while consuming less time.

• 해양환경안전학회지
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• 제29권2호
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• pp.127-138
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• 2023

국제사회는 글로벌 기후위기 극복을 위해 2050년까지 탄소중립(Net Zero)을 목표로 다양한 탈탄소 에너지원 개발을 지속하고 있다. 우리 정부에서도 '재생에너지 3020' 정책을 수립하고 태양광이나 풍력을 이용한 에너지 개발계획을 추진함에 따라 해상 풍력발전단지와 같이 연안해역에서 기존에는 볼 수 없었던 대규모 해양개발사업이 추진되고 있다. 해양시설물은 선박의 입장에서 볼 때는 항행 장애물의 일종이며, 해양시설물 설치에 따라 좁아진 수역에서 선박 간 충돌사고 발생 또는 선박과 해양시설물의 접촉사고 발생시 환경오염 및 인명피해 등의 발생이 우려된다. 이에 국내외의 해상풍력발전단지 개발계획을 살펴보고 풍력단지에서 선박의 안전한 통항을 보장하기 위한 제도적 장치가 완비되어 있는지 분석하였으며, 해외의 입법 사례와 국내 법규를 비교하여 법적 사각지대를 해소하기 위한 새로운 법령안을 제안함으로써 대한민국의 관할해역에서 해양시설물의 안전한 운영과 선박의 안전한 통항을 기대하였다.