P/M Fecralloy의 성형성 및 전기저항특성 향상에 관한 연구

박진우,고병현,정우영,박동규,안인섭,Park, Jin-Woo,Ko, Byung-Hyun,Jung, Woo-Young,Park, Dong-Kyu,Ahn, In-Shup 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.6

The Fe-Cr-Al alloy system shows an excellent heat resistance because of the formation of an $Al_2O_3$ film on the metal surface in an oxidizing atmosphere at high temperatures up to $1400^{\circ}C$. The Fecralloy needs an additive that can act as a binder because of its bad compactability. In this study, the green compacts of STS434L and Al powder added to Fecralloy are oxidized at $950^{\circ}C$ for up to 210 h. Fecralloy and Al is mixed by two types of ball milling. One is vented to air and the other was performed in a sealed jar. In the case of Al addition, there are no significant changes in the electrical resistance. Before the oxidation test, Al oxides are present in the Fecralloy surface, as determined from the energy dispersive spectroscopy results. The addition of Al improves the compactability because of an increased density, and the addition of STS434L increases the electrical resistivity by forming a composite oxide.

타당성 평가가 보완된 모델 운용상의 전투실험 모의분석 절차 연구

박진우,김능진,강성진,서혁,Park, Jin-Woo,Kim, Nung-Jin,Kang, Sung-Jin,Soo, Hyuk 한국시뮬레이션학회 2010 한국시뮬레이션학회 논문지 Vol.19 No.4

Currently, our society has been changed from the industrial society to the information society. As the war progresses to Information Warfare, Network-Centric Warfare, Long-Range Precision Engagement and Robot Warfare, the military should advance to High-tech Scientific force. For this creation of the war potential, it is regarded as the warfighting experiment is a critical method. Surely it is rational that LVC(Live Virtual Constructive simulation) is desirable to make the warfighting experiment. But because it is limited by the cost, the time, the place and the resource, the constructive simulation(M&S : Modeling&Simulation) is a good tool to solve those problems. There are some studies about the evaluation process for developing the model, but it is unsatisfying in the process of the constructive simulations' operation. This study focuses on the way of constructive simulation operation, which is supplied with the evaluation process(VV&A : Verification Validation & Accreditation). We introduce the example of the rear area operation simulation for "appropriateness evaluation to the organization of logistic corps" by the AWAM(Army Weapon Analysis Model). This study presents the effective methods of the constructive simulations, which is based on the reliable evaluation process, so it will contribute to the warfighting experiments.

산화물 혼합상이 페라이트계 P/M스테인리스강의 고온산화 및 전기저항 안정성에 미치는 영향

박진우,고병현,정우영,박동규,안인섭,Park, Jin-Woo,Ko, Byung-Hyun,Jung, Woo-young,Park, Dong-Kyu,Ahn, In-Shup 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.3

In order to improve the high-temperature oxidation stability, sintered 434L stainless steel is studied, focusing on the effect of the addition of metallic oxides to form stable oxide films on the inner particle surface. The green compacts of Fecralloy powder or amorphous silica are added on STS434L and oxidized at $950^{\circ}C$ up to 210 h. The weight change ratio of 434L with amorphous silica is higher than that of 434L mixed with Fecralloy, and the weight increase follows a parabolic law, which implies that the oxide film grows according to oxide diffusion through the densely formed oxide film. In the case of 434L mixed with Fecralloy, the elements in the matrix diffuse through the grain boundaries and form $Al_2O_3$ and Fe-Cr oxides. Stable high temperature corrosion resistance and electrical resistivity are obtained for STS434L mixed with Fecralloy.

P/M Fecralloy 성형체의 고온산화 및 전기저항 안정성에 미치는 SiO₂ 첨가 효과

박진우,옥진욱,정우영,박동규,안인섭,Park, Jin-Woo,Ok, Jin-Uk,Jung, Woo-young,Park, Dong-kyu,Ahn, In-Shup 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.4

A metallic oxide layer of a heat-resistant element contributes to the high-temperature oxidation resistance by delaying the oxidation and has a positive effect on the increase in electrical resistivity. In this study, green compacts of Fecralloy powder mixed with amorphous and crystalline silica are oxidized at $950^{\circ}C$ for up to 210 h in order to evaluate the effect of metal oxide on the oxidation and electrical resistivity. The weight change ratio increases as per a parabolic law, and the increase is larger than that observed for Fecralloy owing to the formation of Fe-Si, Fe-Cr composite oxide, and $Al_2O_3$ upon the addition of Si oxide. Si oxides promote the formation of $Al_2O_3$ and Cr oxide at the grain boundary, and obstruct neck formation and the growth of Fecralloy particles to ensure stable electrical resistivity.

도데실기를 함유한 제4급 암모늄염의 합성과 감량촉진제로서의 응용

박진우,함현식,박홍수 ( Jin Woo Park,Hyun Sik Hahm,Hong Soo Park ) 한국유화학회 1995 한국응용과학기술학회지 Vol.12 No.1

Some weight loss accelerating agents. dodecyltrimethylammonium chloride(DTAC), dodechltrimethylammonium chloride(PDBAC), and 1-(2-hydroxyethyl)-1-benzyl-2-undecylimidazolinium chloride(AEUIC), were synthesized. As a result of weight loss treatment of the weight loss accelerating agents with NaOH to PET fiber, the increase of weight loss was the order of PDBAC > DDBAC > DTAC > DTAB > AEUIC. Among the weight loss accelerating agents, AEUIC hardly showed weight loss effect, and it was separated into two layer in the NaOH solution at the treatment concentration above 6g/L, but POBAC showed good weight loss effect of 21% that approach almost to a theoretical weight loss, 21.6%, at the concentration above 8g/L.

운모기판을 이용한 다결정 Si 전이막 성장 연구

박진우,엄지혜,안병태,정영권,Park Jin Woo,Eom Ji Hye,Ahn Byung Tae,Jun Young Kwon 한국재료학회 2004 한국재료학회지 Vol.14 No.5

We investigated the growth feasibility of polycrystalline Si film on mica substrate for the transfer of the layer to a plastic substrate. The annealing temperature was limited up to $600^{\circ}C$ because of crack development in the mica substrate. Amorphous Si film was deposited on mica substrate by PECVD and was crystallized by furnace annealing. During the annealing, bubbles were formed at the Si/mica interface. The bubble formation was avoided by the Ar-plasma treatment before amorphous Si deposition. A uniform and clean polycrystalline Si film was obtained by coating $NiCl_2$ on the amorphous Si film and annealing at $500^{\circ}C$ for 10 h. The conventional Si lithography was possible on the mica substrate and the devices fabricated on the substrate could be transferred to a plastic substrate.

탈단백 우골의 골이식 대체재로서의 특성에 대한 평가;세 종류의 골 대체재의 기본 특성에 대한 비교분석

박진우,Park, Jin-Woo 대한치주과학회 2005 Journal of Periodontal & Implant Science Vol.35 No.4

Bovine bone-derived bone substitutes are widely used for treatment of bone defects in dental and orthopedic regenerative surgery. The purpose of this study was to evaluate the basic characteristics of deproteinized bovine bone mineral as a bone graft substitute. Commercially available products from three different bovine bone minerals-Bio-Oss(GeistlichPharma, Switzerland), BBP(Oscotec. Korea), Osteograf/N-300(Dentsply Friadent Ceramed, USA) - were investigated. They were evaluated by scanning electron microscopy(SEM), energy dispersive X-ray spectrometer(EDS), surface area analysis(BET), and Kjeldahl protein analysis. Cell viability on different products was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay. The results of this study indicated that each bone substitute displayed distinct surface properties. Furthermore, Kjeldahl protein analysis indicated that residual crude proteins are present in deproteinized bovine bone mineral. BBP showed relatively large amount of residual protein, which indicated that the possibility of disease transmission can not be safely ruled out. Based on the results of this study, it is suggested that active quality management is strongly needed in operations that involve processing bovine bone tissue for medical use.

프랑스 언론의 신뢰도 위기: 저널리즘 제도의 내적 균열과 사회운동의 영향

박진우,김설아,Park, Jin woo,Kim, Soel ah 사단법인 코리아컨센서스연구원 2022 Analyses & alternatives Vol.6 No.2

이 연구는 전 세계적인 언론의 신뢰도 하락이라는 상황에서, 한국 언론과 유사한 형태로 심각한 신뢰 위기를 겪고 있는 프랑스 언론에 대하여 고찰한다. 2018년부터 시작된 '노란 조끼' 운동이라는 거대한 사회운동의 과정에서 프랑스 언론에 대한 불신은 극단적인 형태로 표출되었다. 이 연구는 이를 프랑스 언론의 역사적 발전 과정, 그리고 이에 대한 대중들의 오랜 '언론에 대한 비판'의 구조라는 측면과 결합하여 살펴본다. 구체적으로 이 연구는 로이터 저널리즘 연구소에서 간행한 <디지털 뉴스 리포트>에 나타난 프랑스 언론의 신뢰도의 양적 지표를 먼저 살펴본다. 이어 프랑스 저널리즘의 역사적·제도적 형성 과정 및 이에 발맞추어 등장한 대중적 불신의 경로를 검토해 본다. 그리고 2018년 사회운동에 대한 보도 과정에서 노출된 프랑스 언론의 구조적 위기 - 경제적 위기, 디지털 전환과 경쟁 심화, 퀄리티 저하 - 가 실제 뉴스 생산의 작업 과정에 미친 영향 문제를 검토한다. 결론적으로 이 연구는 프랑스 언론을 향한 외적 충격(사회운동의 영향) 못지 않게, 저널리즘 제도 내부적인 균열의 다양한 양상들이 최근 프랑스 언론의 신뢰도 추락을 설명하는 핵심적인 요인임을 주장한다. This study examines the crisis of trust of French journalism in the context of a global decline of media credibility. First of all, in the process of a huge social movement called the 'yellow vest' movement that started in 2018, distrust of the French journalism was expressed in an extreme form. This study examines some external factors in terms of the historical development of the French journalism and the public's long-standing 'criticism of journalism'. Specifically, this study first examines the quantitative indicators of trust of French journalism which were shown in Digital News Report published by the Reuters Institute for the Study of Journalism. Next, it examines the historical and institutional formation process of French journalism and public distrust that emerged along with it. And specifically, the structural crisis-economic crisis, digital transformation and intensification of competition, and deterioration of quality problems etc.-of the French journalism exposed in media coverage on social movement in 2018 is review in relation with the working process or 'routine' of actual news production. In conclusion, this study asserts that the various aspects of internal rifts in French journalism system, as well as external shocks (the influence of social movements), are a key factor in explaining the recent decline of trust in French journalism.

네트워크 수집정보를 이용한 정보보호 위험도 예측지수 개발

박진우,윤석훈,김진흠,정형철,Park, Jin Woo,Yun, Seokhoon,Kim, Jinheum,Jeong, Hyeong Chul 한국통계학회 2016 응용통계연구 Vol.29 No.7

본 연구에서는 네트워크 가입자들로부터 수집된 악성코드 감염 정보에 기초하여 악성코드 감염에 대한 위험정도를 파악할 수 있는 지수 산출 문제를 다루었다. 계층적 의사결정 방법을 사용하여 여러 악성코드들의 상대적 위험 가중치를 제안하였으며, 이들 가중치를 결합하여 위험도 지수를 산출하였다. 개발된 위험도지수에 대한 시계열 분석 및 통계적 모형 적합을 시도하였으며, 관리도를 통해 정보보호 위험을 예보할 수 있는 지수의 활용성을 살펴보았다. In this paper, we proposed an information security risk index to diagnose users' malware infection situations (such as computer virus and adware) by gathering data from KT network systems. To develop the information security risk index, we used the analytic hierarchy process methodology and estimated the risk weights of malware code types using the judgments of experts. The control chart could be used effectively to forecast the information security risk for the proposed information security risk index data.

이산화티타늄-발광체 복합소재 제조 및 가시광선 광촉매 반응

박진우,김정식,Park, Jin-Woo,Kim, Jung-Sik 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.11

This paper presents a study on the photocatalytic reaction about the composite particles of $TiO_2$-coated phosphors under visible light irradiation. Nanocrystalline titanium dioxide layers were directly coated on the alkaline earth aluminate phosphor, $CaAl_2O_4:Eu^{2+},\;Nd^{3+}$ particles by an sol-gel processing method. The photocatalytic reaction was analyzed with the degradation of methylene blue (MB) aqueous solution under UV and visible light irradiations. $TiO_2$-coated phosphor powders showed different photocatalytic mechanism, compared with pure $TiO_2$ (P-25, Degussa). Under UV-irradiation, $TiO_2$-coated phosphor powders showed slow photocatalytic reactivity in the early stage and fast in the latter, compared with that of pure $TiO_2$. However, $TiO_2$-coated phosphor powders showed much faster photocatalytic reactivity than that of pure $TiO_2$ under visible irradiation. In addition, the characterizations of the $TiO_2$-coated phosphor powders were conducted by a X-ray diffractometer (XRD), transmission electron microscope (TEM), and energy dispersive spectroscopy (EDS).