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.

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.

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.

PDGF-BB 적용시간이 decalcified dentin에서의 치은섬유아세포의 증식에 대한 효과

박진우,이재목,서조영,Park, Jin-Woo,Lee, Jae-Mok,Sun, Jo-Young 대한치주과학회 1996 Journal of Periodontal & Implant Science Vol.26 No.4

Platelet-derived growth factor(PDGF) is one of the polypeptide growth fators. PDGF has been reported as a biological mediator which regulates activities of wound healing process including the cell proliferation, migration and metabolism. Recent studies indicated that demineralized root surface as the primary site for growth factor application has advantages over other application method, especially due to binding capacity of growth factor for exposed matrix component of deminera1ized dentin surface. The purpose of this study is to evaluate optimal application time of PDGF-BB on proliferation of human gingival fibroblasts using deminera1ized dentin surface as primary application site. Human gingival fibroblasts and dentin slabs were prepared from the first premolar tooth extracted for the orthodontic treatment, cells were cultured in DMEM/I0% FBS at the $37^{\circ}C$, 5% CO2 incubator. All of the dentin slabs were preconditioned with Tetracycline HCI(100mg/ml) solution and rinsed in PBS. In the cell proliferation experiment, experimental group was immersed in DMEM containing 10% FBS, 50ng/rnl PDGF-BB during different time(30sec, 1, 2, 4, 8 minutes) and dried. Cells at concentration of $1{\times}10^5$cells/ml were seeded in each culture well which contained dentin slabs and incubated for 6 hours. Then, all of the dentin slabs were moved into new 24 well culture dish and incubated for 24, 48, 72 hours. The cell counting was done by hemocytometer with inverted phase contrast microscope after trypsinization. The results were as follows : The application of PDGF-BB for 1, 2 min slightly increased the number of gingival fibroblasts, and the application of PDGF-BB for 4, 8 min prominently increased the number of gingival fibroblasts. The application of PDGF-BB for 4 min showed maximum proliferation rate of gingival fibroblasts at 24, 48, 72 hours, and the application of PDGF-BB for 8 min showed less proliferation rate of gingival fibroblasts compared to the application of PDGF-BB for 4 min at 24, 48, 72 hours. In conclusion, the application of PDGF-BB for 4 min appeared to be optimal to obtain maximum proliferation of gingival fibroblasts using demineralized dentin surface as primary applicaton site of PDGF-BB.

갑상선 암에서 시도되는 분화유도 요법

박진우,Jin-Woo Park,M,D 대한갑상선-내분비외과학회 2002 The Koreran journal of Endocrine Surgery Vol.2 No.2

Studies on the Anticoagulation Process (Fibrinolysis) by Urokinase I. Purification and Characterization of Urokinase from Human Urine

박진우,이현재,김수자,Park, Jin-Woo,Lee, Hyun-Jae,Kim, Soo-Ja 생화학분자생물학회 1980 한국생화학회지 Vol.13 No.3

Urokinase는 비활성 혈장단백질인 프라스민 전구체를 활성화시키는 효소로서, 이 효소반응의 산물인 프라스민이 혈류의 응혈요소인 피브린 가수분해 과정에 참여될 수 있음으로 이 효소, 즉 Urokinase가 지닌 특성을 연주 검토하였다. 효소 시료의 정제는 ECTEOLA 수지에 의한 이온 교환 크로마토그래피 방법과 알지닌 또는 아그마틴을 ligand로 하는 친화성 크로마토그래피 방법을 도입하여 약 60배의 정제도를 얻었으며 이 경우 효소의 비활성도는 약 1,300 units/mg protein 이였다. 효소의 특성 중 특기할만한 사실은 기질 특성으로서, 다른 단백질 분해 효소인 trypsin과 작용은 비슷하나 프라스민 전구체인 프라스민노젠에만 특이하게 작용함을 알았으며 효소활성도의 최적 pH와 최적온도 등에 있어서도 다른 유사단백질 분해효소들과 다름을 알았다. 그 밖의 효소 특성인 기질에 대한 친화력 및 저해제에 의한 결과 등을 토대로 이 효소가 지난 생리적 역할, 즉 피브린 가수분해 조절기능에 대하여도 검토하여 보았다. The activation of plasminogen to an active fibrinolytic enzyme, plasmin, was studied withe urokinase(EC 3.4.26.99). A crude form of urokinase obtained from human urine was purified partially by an ion exchange column of ECTEOLA and further by an affinity column employing arginine or agmatine as a ligand on Sepharose 4B matrix. The specific activity of the final enzyme preparation was about 1,300 units per ㎎ protein based on the caseinolytic assay measuring the rate of casein hydrolysis by plasmin formed. The mode of the enzyme action seems to be similar to that of trypsin in term of the esterase activity, but the enzyme is found to be very specific toward plasminogen as the substrate. Characteristic properties of the enzyme including molecular weight, pH and temderature optimum, and some kinetic properties were studied and compared with that of the other proteolytic enzyme of trypsin and plasmin. In addition, based on its associative properties, the nature and the physiological role in the fibrinolysis were also discussed.

톳(Hizikia fusiforme)과 모자판(Sargassum fulvellum) 에탄올 및 물 추출물의 아질산염 소거작용

박진우,이문조,윤현민,김철호,Park, Jin-Woo,Lee, Moon-Jo,Yoon, Hyun-Min,Kim, Cheorl-Ho 한국생명과학회 2001 생명과학회지 Vol.11 No.4

The purpose of this study was to investigate the nitrite scavenging activity of the ethanol and water extracts obtained from Hizikia fusiforme and Sargassum fulvelum using sodium nitrite under different pH conditions. The nitrite scavenging activity was appeared in all the extracts examined and it showed the highest value at pH 1.2 The ethanol extract of Hizikia fusiforme provided higher activity than the water extract of that. Ohterwise, the nitrite scavenging activity of Sargassum fulvelum ethanol extract was similar to that Sargassum fulvelum water extract. There was significant difference among concentration of extracts Hizikia fusiforme and Sargassum fulvelum. Also, nitrite scavenging activity of the extracts Hizikia fusiforme and Sargassum fulvelum decreased with higher pH condition. In addition, the activity was increaed with higher concentration of extracts Hizikia fusiforme and Sargassum fulvelum in the course of reaction time 30 minute to 3 hour.

저전력 센서 인터페이스를 위한 1.2V 90dB CIFB 시그마-델타 아날로그 모듈레이터

박진우,장영찬,Park, Jin-Woo,Jang, Young-Chan 한국전기전자학회 2018 전기전자학회논문지 Vol.22 No.3

본 논문에서는 저전력 센서용 아날로그-디지털 변환기를 위한 cascade of integrator feedback (CIFB) 구조의 3차 시그마-델타 아날로그 모듈레이터가 제안된다. 제안된 시그마-델타 아날로그 모듈레이터는 gain-enhanced current-mirror 기반 증폭기를 사용하는 3개의 스위치 커패시터 적분기, 단일 비트 비교기, 그리고 비중첩 클럭 발생기로 구성된다. 160의 오버 샘플링 비율과 90.45dB의 신호 대 잡음비를 가지는 시그마-델타 아날로그 모듈레이터는 1.2V 공급 전압의 $0.11{\mu}m$ CMOS 공정으로 설계되며, $0.145mm^2$의 면적과 $341{\mu}W$의 전력을 소모한다. A third-order sigma-delta modulator with the architecture of cascade of integrator feedback (CIFB) is proposed for an analog-digital converter used in low-power sensor interfaces. It consists of three switched-capacitor integrators using a gain-enhanced current-mirror-based amplifier, a single-bit comparator, and a non-overlapped clock generator. The proposed sigma-delta analog modulator with over-sampling ratio of 160 and maximum SNR of 90.45 dB is implemented using $0.11-{\mu}m$ CMOS process with 1.2-V supply voltage. The area and power consumption of the sigma-delta analog modulator are $0.145mm^2$ and $341{\mu}W$, respectively.

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.