조선 초기 관료의 관청이동을 통해 본 주요 통치기구의 위상 - HAVNet 자료를 중심으로 -

최상일 ( Choi Sangil ),백승민 ( Paek Seungmin ),최지우 ( Choi Jiwoo ),예홍진 ( Yeh Hongjin ),이상국 ( Lee Sangkuk ) 수선사학회 2021 史林 Vol.- No.75

This paper is an introductory study to comprehensively grasp the betweenness centrality of government offices in the early Joseon dynasty using HAVNet data. The process of extracting data around the “Annals of the Joseon Dynasty” and designing and building HAVNet as the basis for research was conducted by history and computer science researchers, which were not the usual method in Korean historical research until now. The approach and analysis results carried out in this study are fundamentally different from previous studies related to the government organizations in the early Joseon dynasty. It is unique study in that it was analyzed based on the contents recorded in the Annals of the Joseon dynasty, not on previous research framework of analysis of state administration and government organizations in the early Joseon dynasty. Based on this study, we will conduct an interdisciplinary research that comprehensively analyzes blood ties and relationships among all historical figures of the Joseon dynasty.

Development of Highly Conductive Poly(3,4-ethylenedioxythiophene) Thin Film using High Quality 3-Aminopropyltriethoxysilane Self-Assembled Monolayer

Sangil Choi, Wondae Kim, Sungsoo Kim 조선대학교 기초과학연구원 2011 조선자연과학논문집 Vol.4 No.4

Quality of PEDOT electrode thin film vapor phase-polymerized on 3- aminopropyltriethoxysilane (APS) self-assembled monolayer (SAM) is very crucial for making an ohmic contact between electrode and semiconductor layer of an organic transistor. In order to improve the quality of PEDOT film, the quality of APS- SAM laying underneath the film must be in the best condition. In this study, in order to improve the quality of APS-SAM, the monolayer was self-assembled on SiO2 surface by a dip-coating method under strictly controlled relative humidity (< 18%RH). The quality of APS-SAM and PEDOT thin film were investigated with a contact angle analyzer, AFM, FE-SEM, and four-point probe. The investigation showed that a PEDOT film grown on the humidity-controlled SAM is very smooth and compact (sheet resistivity = 20.2 Ohm/sq) while a film grown under the uncontrolled condition is nearly amorphous and contains quite many pores (sheet resistivity = 200 Ohm/sq). Therefore, this study clearly proves that a highly improved quality of APSSAM can offer a highly conductive PEDOT electrode thin film on it.

Effect of the mixture preparation on the nanoparticle characteristics of gasoline direct-injection vehicles

Choi, Kwanhee,Kim, Juwon,Myung, Cha-Lee,Lee, Minho,Kwon, Sangil,Lee, Youngjae,Park, Simsoo SAGE Publications 2012 Proceedings of the Institution of Mechanical Engin Vol.226 No.11

<P>Time-resolved nanoparticle number concentrations and size distribution characteristics were investigated in gasoline direct-injection vehicles, according to fuel preparation methods. Particle number emissions were measured using the golden particle measurement system recommended by the Particle Measurement Programme, and the particle size spectrum was determined using a DMS500 spectrometer installed at the tailpipe of the vehicles. The wall-guided gasoline direct-injection vehicle exhibited the most temperature-dependent nanoparticulate matter exhaust characteristics, owing to direct accumulation of fuel on the piston head and cylinder liner and a high concentration of accumulation mode particles. The air-guided gasoline direct-injection vehicle emitted particle emissions mostly during cold transient driving conditions and high acceleration, which had a weak trimodal characteristic with evenly distributed nucleation and accumulation mode particles. The spray-guided gasoline direct-injection vehicle continuously discharged 10(5) particles/cm(3) during constant-speed driving segments, because of the ultra-lean-burn operation and bulk quenching; particulate matter from the spray-guided gasoline direct-injection vehicle demonstrated a strong bimodal characteristic, spreading over 10-100 nm. The particle number emissions for the gasoline direct-injection vehicles for the New European Driving Cycle test mode were 1.48 x 10(12) particles/km, 6.03 x 10(11) particles/km and 3.17 x 10(12) particles/km for the wall-guided type, the air-guided type and the spray-guided type respectively, and none of these were able to satisfy the proposed particle number regulations for the Euro 6 standard. For gasoline direct-injection vehicles, it should be considered that engine hardware modifications, as well as energy management system calibrations and even the application of the particle filter, may be needed to meet the upcoming particulate matter number regulation.</P>

A Study of Fracture Behavior of Spent Fuel in Long-Term Dry Storage

Sangil Choi,Sangsoon Cho,Seunghwan Yu 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

To investigate the mechanical integrity of spent nuclear fuel, the failure behavior of the cladding tube was examined under accident conditions. According to the SNL report, the failure behavior of cladding can be broadly classified into two types. The first is failure due to bending load caused by falling. The second is failure due to pinch load caused by space grid. In this study, mechanical integrity was evaluated through the stress intensity factor applied to the crack in failure behavior due to bending load. Since the exact value of the impact load due to fall was unknown, the load was applied by increasing the value up to 200 G in 20 G increments. The size of the crack is an important input variable, and 300 um was given by referring to the EPRI report, and the elastic modulus, a material property that determines the stress field, was given 75.22 GPa by referring to the FRAPCON code. Since the relationship between the direction of stress and the direction of the crack is also a major variable, simulations were conducted for both cracks perpendicular to and parallel to the stress direction. It was confirmed that at a load of 200 G, when the crack was parallel to the stress direction, stress concentration did not occur and had a very low stress intensity factor 0.01 ???√?. When perpendicular to the direction of stress, the stress intensity factor showed a value of 1 ???√?. However, considering that the critical value of the stress intensity factor due to hydride is 5 ???√?, it can be seen that perpendicular result also ensures the mechanical integrity of the cladding.

Study on Poly(3,4-ethylenedioxythiophene) Thin Film Vapour Phase-Polymerized with Iron(III)Tosylate on AcOH-Catalyzed 3-Aminopropyltriethoxysilane Self-Assembled Monolayer

Sangil Choi, Wondae Kim, Sungsoo Kim 조선대학교 기초과학연구원 2012 조선자연과학논문집 Vol.5 No.4

In this study, PEDOT thin films polymerized with Iron(III)tosylate (Fe(PTS)3) and grown on acetic acid-catalyzed 3- aminopropyltriethoxysilane self-assembled monolayer (APS-SAM) surfaces by VPP method have been investigated. PEDOT thin films were synthesized on APS self-assembled SiO2 wafer surface at two different concentrations (20 wt% and 40 wt%) and growth time (3 and 30 minutes), and then they were compared. PEDOT vapour phase-polymerized with 40 wt% Fe(PTS)3 oxidant completely formed a thin film on acetic acid-catalyzed APS-SAM surface while with 20 wt% Fe(PTS)3 did not at all. It means that the oxidant can be uniformly coated on acetic acid-catalyzed APS-SAM surface at the 40 wt% concentration, which gives rise to the uniform growth of PEDOT thin film on it.

프로세스 중심 소프트웨어공학 환경의 구성요소간 인터페이스 설계에 관한 연구

최상일,이형원 국립7개대학공동논문집간행위원회 2002 공업기술연구 Vol.2 No.-

In order to produce a high-quality software product on planned time, all the software development processes should be effectively managed. Process-centered software engineering environments(PCSEEs) are software engineering environments in which software processes are explicitly defined, modeled and enacted. In this paper, we defined interfaces between components of PCSEEs such as process engine, resource manager and agent manager. These interfaces are major building blocks for PCSEEs, so they can be applied to implement a variety of PCSEEs. Also, we simulated the interfaces with a rule-based language CLiPS.

Effect of HCl Chemical Reaction Etching on Thick Semipolar (11–22) GaN Growth by Hydride Vapor Phase Epitaxy

Choi, Uiho,Woo, Seohwi,Lee, Sangil,So, Byeongchan,Nam, Okhyun American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11

<P>In this paper, we report on the crystal quality improvement and self-separation of semipolar GaN by HCl chemical reaction etching (HCRE) using a hydride vapor phase epitaxy (HVPE) system. After HCRE, the surface roughness of the seed layer increased owing to etch pit generation and voids formed at the interface between the seed layer and the m-sapphire. The HCRE was effective for improving crystal quality as shown by the full width at half maximum (FWHM) and decreased anisotropy of the regrown thick semipolar GaN template. This was attributed to defect bending during regrowth due to the etched rough surface of the seed layer. Finally, a 150-mu m-thick GaN layer was grown after seed layer etching to confirm the possibility of self-separation. Self-separation occurred during the cooling down process, because of thermal stress concentration on the voids formed at the interface between GaN and sapphire by HCRE. The self-separated GaN piece substrate was strain-free and possessed an improved crystal quality, although the self-separation process should be optimized to obtain a single 2-in. wafer.</P>

Development of High-Quality Poly(3,4-ethylenedioxythiophene) Electrode Pattern Array Using SC1 Cleaning Process

Sangil Choi, Wondae Kim, Sungsoo Kim 조선대학교 기초과학연구원 2011 조선자연과학논문집 Vol.4 No.4

Application of self-assembled monolayers (SAMs) to the fabrication of organic thin film transistor has been recently reported very often since it can help to provide ohmic contact between films as well as to form simple and effective electrode pattern. Accordingly, quality of these ultra-thin films is becoming more imperative. In this study, in order to manufacture a high quality SAM pattern, a hydrophobic alkylsilane monolayer and a hydrophilic aminosilane monolayer were selectively coated on SiO2 surface through the consecutive procedures of a micro-contact printing (μCP) and dipcoating methods under extremely dry condition. On a SAM pattern cleaned with SC1 solution immediately after μCP, poly(3,4-ethylenedioxythiophene) (PEDOT) source and drain electrode array were very selectively and nicely vapour phase polymerized. On the other side, on a SC1-untreated SAM pattern, PEDOT array was very poorly polymerized. It strongly suggests that the SC1 cleaning process effectively removes unwanted contaminants on SAM pattern, thereby resulting in very selective growth of PEDOT electrode pattern.

A Study of Mechanical Degradation Behavior of Spent Fuel in Long-term Dry Storage

Sangil Choi,Sangsoon Cho,Seunghwan Yu 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Research on the safety of nuclear spent fuel has been heavily experimented and modelled from a mechanical perspective. The issues of corrosion, irradiation creep, hydride and hydrogen embrittlement have been addressed more than two decades since the early 2000s. Among these degradation behavior, hydrogen embrittlement and hydride reorientation have been the most important topics for establishing the integrity of nuclear spent fuel and have been studied in depth. In order to assess the safety of spent nuclear fuel, firstly, it is necessary to establish the safety criteria in all nuclear cycle, i.e., the failure criteria guidelines for nuclear fuel assemblies and nuclear fuel rods, and then examine the safety analysis. The contents of U.S.NRC Regulations, Title 10 General, Chapter 1 Code of Federal Regulation (CFR), Part 50, 71 and 72, describe the safety criteria for the safety assessment of nuclear fuel assemblies and nuclear fuel rods. In this study, technically important points in safety analysis on nuclear fuel are checked through the reference of those NRC regulation. As result, we confirmed that the safety assessment of nuclear fuel after 20 years of interim storage is now being tested by ORNL and PNNL. There are not quantitative criteria related to material safety. However qualitative criteria which is dependent on environmentally condition describe the safety analysis. There is some literature study about DBTT, yield stress, ultimate tensile strength, flexural rigidity data. In FRAPCON code Modelling of yield strength and creep had been established, but radial hydride or hydride reorientation has not considered.

Block Design-Based Asynchronous Neighbor Discovery Protocol for Wireless Sensor Networks

Choi, Sangil,Lee, Wooksik,Song, Teukseob,Youn, Jong-Hoon Hindawi Limited 2015 Journal of sensors Vol.2015 No.-

<P>Neighbor discovery is a significant research topic in wireless sensor networks. After wireless sensor devices are deployed in specific areas, they attempt to determine neighbors within their communication range. This paper proposes a new Block design-based Asynchronous Neighbor Discovery protocol for sensor networks called<I>BAND</I>. We borrow the concept of combinatorial block designs for neighbor discovery. First, we summarize a practical challenge and difficulty of using the original block designs. To address this challenge, we create a new block generation technique for neighbor discovery schedules and provide a mathematical proof of the proposed concept. A key aspect of the proposed protocol is that it combines two block designs in order to construct a new block for neighbor discovery. We analyze the worst-case neighbor discovery latency numerically between our protocol and some well-known protocols in the literature. Our protocol reveals that the worst-case latency is much lower than others. Finally, we evaluate the performance of<I>BAND</I>and existing representative protocols through the simulation study. The results of our simulation study show that the average and maximum latency of<I>BAND</I>is about 40% lower than that of existing protocols. Furthermore,<I>BAND</I>spends approximately 30% less energy than others during the neighbor discovery process.</P>