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.

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.

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.

갑상선암 세포주에서 Troglitazone에 의한 TRAIL-유도 세포소멸 감수성의 증가

박진우,OrloH.Clark<SUP>1<.SUP>.Jin-Woo Park and Orlo H. Clark<SUP>1<.SUP> 대한갑상선-내분비외과학회 2003 The Koreran journal of Endocrine Surgery Vol.3 No.2

Purpose: Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) induces apoptosis in many human cancer cells but not in normal cells. Thyroid cancer cells, however, appear to be relatively resistant to TRAIL-induced apoptosis. We investigated the effect of troglitazone, a PPARγ agonist, on TRAIL-induced apoptosis in thyroid cancer cells. Methods: We used 6 thyroid cancer cell lines: TPC-1, FTC- 133, FTC-236, FTC-238, XTC-1, and ARO82-1. We used flow cytometry to detect apoptosis and used MTT assay to measure anti-proliferation effects. ANOVA was used for statistical analysis. Results: TPC-1 cells were the most sensitive to soluble TRAIL. FTC-133 and ARO82-1 were resistant to TRAIL and growth inhibition was less than 20% at concentration of 800 ng/ml of TRAIL. In both TPC-1 (TRAIL-sensitive) and FTC- 133 (TRAIL-resistant) thyroid cancer cell lines, pretreatment with troglitazone enhanced TRAIL-induced cell death significantly. Bcl-family proteins did not seem to be involved in sensitization of TRAIL-induced apoptosis by troglitazone. Conclusion: TRAIL in combination with troglitazone induces apoptosis in thyroid cancer cells at suboptimal concentrations that can not be achieved using TRAIL alone. (Korean J Endocrine Surg 2003;3:113-120)

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.

Active Site Functional Residues of Urokinase as a Plasminogen Activator

박진우,김수자,이현재,Park, Jin-Woo,Kim, Soc-Ja,Lee, Hyun-Jae 생화학분자생물학회 1983 한국생화학회지 Vol.16 No.2

In order to elucidate the mechanism of the urokinase- induced plasminogen activetion, catalytically active functional groups which involved in the active site of urokinase molecule were investigated by a series of kinetic and chemical modification experiments. Inhibition study with several lysine and arginine derivatives indicates there involves hydrophobic interaction between urokinase and plasminogen molecules. 6-Amino hexanoic acid shows an exceptional high degree inhibition. The results from a set of pH-activity profiles and several chamical modification experiments suggest there involve at lease one serine hydroxyl moiety and one histidine imidazole group in the active site of the activator urokinase for the catalytic conversion of plaminogen into plasmin. Based on the results obtained, a minimal three step mechanism of the UK-induced plasminogen activation process was proposed as a working model. Urokinase에 의한 plasminogen 활성화 반응은 urokinase-plasminogen 복합체인 acyl-중간체를 경유하는 것으로 믿어지며, urokinase 분자내 활성화 부위 작용기로서는 histidine imidazole 잔기와 serine hydroxyl가 각각 염기성 및 천핵성 촉매제로서 작용, plasminogen의 활성화 반응에 참여될 수 있음을 pH 변화에 따른 반응 속도론적 실험과 착용기에 대한 화학적 불활성화 실험을 통하여 입증할 수 있었다. 아울러 본 연구결과를 토대로 하여 urokinase에 의하여 유도되는 plasminogen 활성화 반응에 대한 3단계 반응 메카니즘도 구상 검토해 보았다.

CO₂ 수송선 저장탱크의 BOG 측정 실험 및 회수에 관한 연구

박진우,김동선,고민수,조정호,Park, Jin-Woo,Kim, Dong-Sun,Ko, Min-Su,Cho, Jung-Ho 한국청정기술학회 2014 청정기술 Vol.20 No.1

화석연료로부터 에너지를 얻을 때, 연소반응에 의해 이산화탄소가 생성되어 진다. 이렇게 이산화탄소의 배출이 늘어나게 되면 지구온난화 문제가 더욱 심각해지게 된다. 따라서 이를 방지하기 위한 이산화탄소 포집 및 저장기술(carbon capture and storage, CCS) 개발이 요구되고 있다. 하지만 액화 이산화탄소를 수송 시 여러 문제로 인해 지속적으로 BOG (boil-off gas)가 발생하게 된다. 본 연구에서는 $40m^3$저장 탱크 2대에 액화 이산화탄소를 주입하여 압력변화 및 외부열과 선적, 하역 시 발생하는 BOG의 양과 조성을 30일 간 측정하였다. 측정한 결과 16,040 kg의 BOG가 발생하였으며, 조성은 $CO_2$ 99.95%, $N_2$ 0.05%인 것을 알 수 있었다. 또한 상용성 모사기인 PRO/II with PROVISION 9.2를 이용하여 발생한 BOG를 증기 재압축 냉동사이클을 통해 재액화 하는 전산모사를 수행하였다. 그 결과 냉동사이클의 총 순환유량은 42.07 kg/h, 응축기 설비의 소모량은 48.85 kg/h가 나오는 것을 알 수 있었다. $CO_2$ is generated by the combustion reaction, when getting the energy from fossil fuel. If the carbon dioxide emissions increases more, the global warming problem will become more serious. CCS (carbon capture storage) needs to be developed for the prevention of this. When liquefied $CO_2$ is transported, BOG (boil-off gas) is generated because of several problems. In the study, by injecting liquefied $CO_2$ in two tanks which contains $40m^3$each, the amount of BOG and its composition were measured during 30 days when generating pressure changes and external heat, loading, unloading. In result, 16,040 kg of BOG was generated and the composition has been found out to be 99.95% $CO_2$ and 0.05 % $N_2$. Also, we conducted simulation process for reliquefaction of generated BOG with vapor compression cycle using the PRO/II with PROVISION version 9.2. As a result, the refrigeration cycle of the total circulation flow rate was 42.07 kg/h and the condenser utility consumption was 48.85 kg/h.

LVQ 자력등화를 이용한 와이브로 시스템의 성능 개선

박진우,Park, Jin-Woo 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.10

WiBro(Wireless Broadband Internet) is the standard of high-speed portable internet based on OFDMA/TDD (Orthogonal frequency division multiple access / Time division duplexing) techniques, and the subset of consolidated version of IEEE802.16e Wireless MAN standard. In this paper, we propose performance improvements of WiBro system using the LVQ(Learning Vector Quantization) blind equalization. Proposed method used the prefiltering LVQ neural network blind equalization in the Broadband WiBro system receiver. The prefiltering LVQ neural network constellates 16QAM that is transmitter data shape and the blind equalization removes ICI(Inter Carrier Interference). To verificate the proposed method usability, the MSE(Mean Square Error) and the BER(Bit Error Rate) are simulated. The simulation results shown that is improved the performances of the proposed WiBro system using the LVQ blind equalization than the existing WiBro system. 와이브로는 OFDMA/TDD 기술을 기반으로하는 고속 이동 인터넷 표준이고, IEEE802.16e 무선 MAN 표준 통합버전의 하나이다. 본 논문에서는 LVQ 자력등화를 이용한 와이브로 시스템의 성능 개선을 제안하였다. 제안한 방법은 Broadband 와이브로 시스템 수신단에 전처리 LVQ 신경망 자력등화를 사용한다. 전처리 LVQ 신경망은 송신데이터 형태인 16QAM으로 분류하고 자력등화는 ICI를 제거한다. 제안한 방법의 유용성을 확인하기 위하여 MSE와 BER에 대하여 시뮬레이션 하였으며, 시뮬레이션 결과 제안한 LVQ 자력등화를 이용한 와이브로 시스템은 기존의 와이브로 시스템보다 성능이 개선되었음을 확인하였다.

갑상선 종양의 발병 기전

박진우,Jin-Woo Park 대한갑상선-내분비외과학회 2010 The Koreran journal of Endocrine Surgery Vol.10 No.2

Thyroid tumors display an intriguing biological diversity from benign follicular adenomas to lethal anaplastic carcinomas. Thyroid tumorigenesis is becoming better understood. Benign follicular adenomas are frequently associated with mutation of the thyrotrophin receptor, G alpha s or RAS. Although confirmatory studies are necessary, the present knowledge concerning the similarity in gene expression profiling between follicular adenomas and follicular carcinomas supports the progression of adenoma to carcinoma sequence. Four major genetic aberrations in follicular cell- derived thyroid carcinomas such as papillary, follicular, and Hurthle cell carcinomas include mutations of BRAF or RAS, and chromosomal rearrangement of RET/papillary thyroid tumor or PAX8/peroxisome proliferator-activated receptor gamma. Differentiated thyroid carcinomas of follicular cell origin dedifferentate to poorly differentiated or anaplastic thyroid carcinomas through mutation of p53 and CTNNB1. Familial nonmedullary thyroid carcinomas are heterogenous in genetic profiling, but some genes have been investigated as candidates for causative genetic aberration. Ret mutations can cause medullary thyroid carcinomas. A genotype-phenotype relationship helps to decide prophylactic thyroidectomiesin family members of hereditary medullary carcinomas such as MENIIa or MENIIb. Primary thyroid lymphomasare closely related with Hashimoto's thyroiditis. Recent novel and promising findings include additional abnormalities in the regulation of microRNA expression, polymorphisms associated with thyroid cancer susceptibility and epigenetic changes. A newly proposed fetal cell carcinogenesis hypothesis explains more about thyroid tumorigenesis than classical multi-step carcinogenesis model, but is not yet firmly supported by evidence. Future studies need to uncover new molecular mechanisms in thyroid tumorigenesis and to provide novel therapeutic targets for thyroid carcinomas. (Korean J Endocrine Surg 2010;10:79-87)