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유동층 소각로 내부 유동 현상과 폐 추진체 연소 반응 모사
이지헌(Jiheon Lee),박찬호(Chanho Park),김현수(Hyunsoo Kim),박정수(Jungsoo Park),오민(Min Oh),문일(Il Moon) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
최근 환경문제로 인해 폭발성 폐기물을 안전하게 소각 처리하는 방법에 대한 연구가 활발히 진행되고 있다. 유동층 소각로를 이용한 처리 공정은 기존 방법보다 연소 가스 배출량이 현저하게 낮으며, 운전의 효율 또한 높다. 본 연구에서는, 폐 추진제 중 가장 많은 양이 폐기되고 있는 Double Base Propellant(이하 DBP)를 유동층 소각로에서 소각하는 공정을 전산유체역학 프로그램으로 모사하였다. Cylindrical Bed 내부에서 일어나는 7개의 연소 반응이 안전하게 모사되는 것을 확인하였다. 이를 바탕으로 실제 공정 설계를 진행하면, 앞으로 폭발성 폐기물 처리 공정 연구에 새로운 연구 방향을 제시할 것이라 사료된다. Thesedays, a number of research about method to treat the explosive wastes are performed due to the environmental pollutions. A combustion process using fluidized bed incinerator has several profits. It doesn’t have a lot of pollute gas such as NOx, and the efficiency of the process is higher than other processes. In this study, I’m focusing on Double-base propellant combustion reaction and doing dynamic simulation. And, I found the reactions are simulated in cylindrical bed successfully. This study will influence to the research about treatment of explosive wastes.
녹색 에너지 자립섬을 위한 스마트 그리드 운영 프레임워크
박지헌(Jiheon Park),류광렬(Kwang Ryel Ryu) 한국컴퓨터정보학회 2014 한국컴퓨터정보학회 학술발표논문집 Vol.22 No.1
에너지 자립섬은 외부 전력의 유입이 어려운 상황에서 풍력/태양광 발전과 같은 재생 에너지를 주요 발전원으로 운영하는 섬이다. 에너지 자립섬의 운영을 위해서는 전력 수요와 공급량을 예측하여 발전기, 송배전 시스템, ESS 등의 운영 계획 수립이 필요한데 수요 및 공급의 예측은 기상 상황 및 시간 등의 다양한 요소에 영향을 받으므로 예측이 어렵다. 이러한 특성을 감안하여 효율적인 전력망 운영을 위해 기계 학습을 기반으로 한 스마트 그리드 운영 프레임워크의 활용을 통해 이 문제를 해결하고자 한다. 본 논문에서는 자립섬 운영 계획 수립에 필요한 구성 요소를 파악하고 요소들 간의 연계 관계를 분석하여 운영 시스템의 프레임워크 설계안을 제시한다.
Fabrication of Electroplate Sn-Ag Bumps Without a Lithography Process for 3D Packaging
Jiheon Jun,Jun Kyu Park,정재필 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.3
A new process of electroplate Sn-Ag bumping without a patterned photo resist (PR) mould on a Si chip for 3-dimensional packaging was investigated. The electroplating characteristics of the Sn-Ag electrolyte and the bump growth were examined. The substrate was a Si die with a thickness of 70 µm in which the through-Si-vias (TSVs) were plugged with Cu. The Sn-Ag bumps were electroplated on the Cu-plugged vias of the Si-chip with an increasing DC current density and plating time. The experimental results of the polarization curve showed that Sn-Ag had two reduction potentials, namely, a Ag reduction starting poten-tial of −0.387V and a Sn and Ag co-reduction potential of −0.474 V. The Sn-Ag bumps were fabricated successfully without serious defects by electroplating without a PR mould. The bump height and width increased to 14.5 and 72.0 µm, respectively, when the plating time was raised to 15 min. The growth of the bump width was caused by the absence of the PR mould. The Sn-Ag bump exhibited rivet-head mor-phology in 15 min plating, and no short circuit between neighboring bumps was found. The near eutectic composition of Sn-3.24 wt%Ag bump was obtained by plating at −30 mA/cm2 for 15 min.
Jiheon Ryu,Hae-Ok Kwon,Seung Hyuk Park,Dong Woo Yim IEEE 2016 IEEE transactions on instrumentation and measureme Vol.65 No.3
<P>This paper presents a square patch capacitive voltage divider (CVD) for measuring high-voltage ultrawideband pulses in a coaxial pulse forming line. The dimension parameters and the sensitivity factor of the CVD are expressed as functions of the low-frequency cutoff and the high-frequency cutoff of the pulse waveform via a theoretical analysis in frequency domain. A coaxial line integrated with a square patch CVD is designed, manufactured, and tested. A 1.3-ns bipolar pulse is measured by the CVD. The experimental results demonstrated that the waveform measured by the CVD was nearly identical to the reference waveform and the error of the maximum amplitude was 2.1%.</P>
Park, Chanho,Lee, Jiheon,Cho, Hyungtae,Kim, Youngjin,Cho, Sunghyun,Moon, Il Elsevier 2018 Powder technology Vol.325 No.-
<P><B>Abstract</B></P> <P>The variance among bin counts is one of the most effective and convenient indices to quantify the degree of spatial distributive mixing. Although it is suitable for evaluating the spatial distribution of unimodal particles, many practical particle-mixing processes involve bimodal or multimodal particle systems. Herein, the variance among bimodal bin counts is introduced as a new mixing index to quantify the degree of distributive mixing of bimodal or multimodal particles. Four bimodal particle-mixing systems are assumed and analyzed to evaluate index performance: balanced versus imbalanced and fully versus partially distributed particle systems. As a result, we suggest practical usage and the most effective variation of variances among conventional bin counts and bimodal bin counts to quantify the four bimodal particle-mixing systems. Furthermore, variations of the method for evaluating multimodal mixing are proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We proposed a new mixing index for quantifying the degree of mixing. </LI> <LI> The new index is the variance among bimodal bin counts. </LI> <LI> Four bimodal particle-mixing systems are assumed and analyzed. </LI> <LI> Variations of the method for evaluating multimodal mixing are also proposed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>