중력주조 AM60 마그네슘 합금의 강화 거동에 미치는 Si 및 Ca 첨가영향

김재우,김도향,신광선 ( Jae Woo Kim,Do Hyang Kim,Kwang Seon Shin ) 한국주조공학회 1998 한국주조공학회지 Vol.18 No.4

N/A Effects of Si and Ca additions on the mechanical properties of AM60 based Mg alloys have been investigated. Hardness of the AM60 based Mg alloys reached a maximum value after aging for approximately 33 hours but the amount of hardness increase was negligible. The poor age hardening response of the alloys was due to low Al content, which implies that Al content must be >6 wt.% to observe age hardening effect. The tensile and yield strength increased with increasing AI, Si, and Ca content but elongation decreased with increasing Al and Si content. The best mechanical properties obtained in AM 40-2.5Si-0.2Ca alloy after T4 heat treatment were as follows; tensile strength 193.4 MPa, yield strength 79.2 MPa, and elongation 11.2%. High temperature property obtained from creep test was also improved by introducing Mg₂Si which has high hardness, high melting temperature and low thermal expansion coefficient. (Received February 6, 1998)

통합 모델 설계 방식 기반 통신 프로토콜 개발을 위한 SDL-OPNET 모델 변환 기법

김재우,김태형,Kim, Jae-Woo,Kim, Tae-Hyong 대한임베디드공학회 2010 대한임베디드공학회논문지 Vol.5 No.2

Although both functional verification and performance evaluation are necessary for the development of effective and reliable communication systems, they have been often performed independently; by functional modeling with formal language tools and by performance modeling with professional network performance evaluation tools, respectively. Separate and repeated modeling of one system, however, would often result in cost increase and inconsistency between the models. This paper proposes an integrated model design approach in order to overcome this problem that evaluates the performance of a communication protocol designed in SDL with SDL-OPNET model conversion. The proposed technique generates OPNET skeleton code from Tau-generated C code of the SDL model by analyzing the relations between SDL and OPNET models. IEEE 802.2 LLC protocol was used as an example of model conversion to show the applicability and effectiveness of the proposed technique.

공동주택 생산성 데이터 수집/분석을 위한 WBS 개발

김재우,김예상,김영석,김상범,Kim, Jae-Woo,Kim, Yea-Sang,Kim, Young-Suk,Kim, Sang-Bum 한국건설관리학회 2008 건설관리 : 한국건설관리학회 학회지 Vol.9 No.5

생산성은 모든 생산조직의 견실성 및 생산 활동의 효율성 평가를 위한 매우 중요한 경영 지표 중 하나로써 생산성의 기능은 건설 산업에 있어서도 예외일 수 없다. 그러나 국내의 경우 생산성의 중요성과 그 기능에도 불구하고 건설 생산성 관리와 관련된 사항은 대부분 현장관리자의 경험과 직관에 의존하고 있으며 생산성 데이터를 데이터베이스화하여 공사계획 및 관리에 적극활용하지 못하고 있다. 이러한 문제는 생산성 데이터와 관련된 정보의 수집 및 분석 방법이 체계적이지 못한 결과로, 생산성 데이터의 효과적인 활용을 위해 우선적으로 WBS개선이 이루어져야 한다. 따라서 본 연구에서는 연구문헌 분석, 해외사례 분석으로 연구에 적용함에 따른 적합여부 및 개선사항을 도출하고, 현장 인터뷰를 통해 현장여건을 반영한 후, 설정된 기본방향을 바탕으로 생산성 데이터 수집 및 분석을 위한 WBS를 구축하였다. 마지막으로 생산성 데이터 수집 및 분석을 위한 체계로의 검증을 실시하였다. 향후 구축된 WBS를 통해 수집된 생산성 데이터는 OLAP을 이용한 생산성 분석 및 Data Mining을 이용한 생산성 예측에도 활용될 것으로 기대된다. Productivity is one of key management indexes for evaluating soundness of a manufacturing organization and its efficiency. In many aspects of productivity management in the construction industry, however, intuition of an experienced field manager still plays a greater role while productivity data is not utilized efficiently for the construction management purposes, because the collection and analysis of the productivity-related information are not systematic. Lack of systematic method in collecting and analyzing the productivity data results in such problems. The existing WBS should therefore be improved to solve them. The authors developed a new WBS for productivity data collection and analysis by following the research direction that was determined by literature reviews, overseas cases, and interviews with field engineers. The new breakdown structure was then evaluated for its feasibility as a productivity analysis framework. It is expected that the productivity data collected by the WBS will be used for OLAP and mining for future productivity forecast.

혈청결핍 상태에서 크레아틴이 RGC-5세포의 생존에 미치는 영향

김재우,홍정흠,강선희,김윤영,Jae Woo Kim,Jung Heum Hong,Sun Hee Kang,Yun Young Kim 대한안과학회 2011 대한안과학회지 Vol.52 No.5

Purpose: To evaluate the protective effect of creatine on the survival of retinal ganglion cells after serum deprivation. Methods: RGC-5 cells were exposed to 5 mM creatine with serum-free media for 4 days. Cellular survival and mitochondrial respiratory activity were measured with MTT assay and resazurin assay, respectively. Degree of apoptosis was evaluated with vital staining using acridine orange/Hoechest 33342 and flow cytometric analysis using annexin/PI, respectively. Results: Creatine increased cellular survival of RGC-5 cells significantly after serum deprivation. Additionally, creatine increased mitochondrial respiratory activity and inhibited apoptosis of RGC-5 cells. Conclusions: The energy precursor creatine increased survival of retinal ganglion cells after serum deprivation. Creatine could be relevant for the cytoprotection of retinal ganglion cells. J Korean Ophthalmol Soc 2011;52(5):618-623

안정동위원소의 분야별 이용현황과 전망 - 의료 및 연구분야

김재우,정도영,김철중,Kim, Jae-U,Jeong, Do-Yeong,Kim, Cheol-Jung 한국동위원소협회 2006 동위원소회보 Vol.21 No.2

프로스타글란딘F2α가 배양된 섬모체근세포의 산화질소 생성에 미치는 영향

김재우,김윤영,김근해,Jae Woo Kim,M,D,Yoon Young Kim,M,D,Keun Hae Kim,M,D 대한안과학회 2005 대한안과학회지 Vol.46 No.1

Purpose: To investigate whether prostaglandin F2α (PGF2α) affects on the production of nitric oxide (NO) in cultured ciliary muscle (CM) cells. Methods: Following primary culture of CM cells from porcine eyes, the cells were exposed to PGF2α (PhXA85, latanoprost free acid) with and without pretreatments of NO synthase inhibitor (L-NAME, Nω- Nitro-L-arginine methyl ester) and cyclooxygenase inhibitors (indomethacin and dexamethasone) for 3 days. The cellular survivals were also evaluated in serum-deprived and hypoxic conditions induced by sodium cyanide. The cellular survival and nitrite production were assessed by MTT and Griess assay, respectively. Results: PGF2α enhanced the production of NO significantly in cultured CM cells in a dose-dependent manner, while various inhibitors abolished this effect. PGF2α was not cytoprotective in serum-deprived and hypoxic conditions. Conclusions: The current results suggest that PGF2α potentiates NO production but is not cytoprotective in CM cells. This PGF2α-induced NO production in CM cells may be involved in the regulation of uveoscleral outflow.

과산화수소에 의한 산화스트레스가 섬유주세포의 노화에 미치는 영향

김재우,김신후,이재형,Jae Woo Kim,Sin Hoo Kim,Jae Hyung Lee 대한안과학회 2008 대한안과학회지 Vol.49 No.10

Purpose: To investigate the effects of oxidative stress on the senescence of trabecular meshwork (TM) cells and the effect of L-ascorbic acid (LAA) against oxidative stress-induced senescence. Methods: Primary cultured human TM cells were exposed to 0.05 or 0.1 mM hydrogen peroxide for 30 minutes and incubated for 1 week with or without co-exposure of LAA. Cellular survival, nitrite production, and senescence were assessed with MTT, Griess, and SA-β-gal assays, respectively. Results: Hydrogen peroxide decreased cellular survival and NO production accompanied increased cellular senescence. LAA did not prevent hydrogen peroxide-induced senescence. Conclusions: Oxidative stress-induced senescence of TM cells may be related to the dysfunction of trabecular meshwork in glaucoma. J Korean Ophthalmol Soc 2008;49(10):1665-1670

은행잎추출물이 배양된 테논낭 섬유아세포의 증식에 미치는 영향

김재우,김성재,강현구,Jae Woo Kim,M,D,Seong Jae Kim,M,D,Hyun Ku Kang,M,D 대한안과학회 2006 대한안과학회지 Vol.47 No.4

Purpose: To investigate the effect of Ginkgo biloba extract (GBE) on the proliferation of cultured human Tenon capsule fibroblasts (HTCF). Methods: Free radical scavenging activity of GBE was assessed with a DPPH assay. Primarily cultured HTCF were exposed to 10 and 100 ?g/ml of GBE, and the effect of this extract on HTCF survival was assessed. Following 48 hr exposure to the media with or without serum, cellular survival and nitrite production were assessed by MTT and Griess assays. To evaluate whether GBE had a cytoproptective effect, HTCF were cultured in a combination of GBE and either sodium cyanide or hydrogen peroxide. Results: GBE showed free radical scavenging activity. GBE increased the cellular survival of HTCF significantly in a dose-dependent manner and provided a cytoprotective effect when cells were exposed to sodium cyanide or were deprived of serum, but not when hydrogen peroxide was added to the medium. GBE decreased nitric oxide production but not to a statistically degree. Conclusions: GBE promotes proliferation of HTCF and has a cytoprotective effect in serum-deprived or hypoxic conditions. This suggests that GBE may be involved in the regulation of conjunctival wound healing by increasing the survival of HTCF.

쓰레기 소각재 사용 콘크리트의 품질특성에 대한 실험적 연구

김재우,최재진,문대중,Kim, Jae-Woo,Choi, Jae-Jin,Moon, Dae-Joong 한국건설순환자원학회 2014 한국건설순환자원학회 논문집 Vol.2 No.4

쓰레기 소각재(소각재)를 콘크리트용 재료로 재활용하기 위하여 소각재의 품질특성에 대하여 분석하였으며, 소각재를 사용한 콘크리트의 유동특성 및 강도특성에 대하여 검토하였다. 소각재의 화학성분은 CaO 성분이 50%이상을 차지하고 있었으며, 소각재의 누적입도분포 50%의 평균입경은 $25{\mu}m$ 정도를 나타내었다. 소각재 IA1의 입자형상은 미세입자가 뭉쳐져 구형상을 나타내고 있으며, 소각재 IA2의 입자형상은 미세입자가 판상 형상으로 겹쳐져 있는 구조로 제조공정에 따라 다르게 나타났다. 소각재를 사용하므로써 콘크리트의 품질특성에도 크게 영향을 미쳤으며, 소각재 IA2를 사용한 경우 슬럼프가 증가하고 고성능감 수제 사용량이 감소하였으나, 압축강도 발현은 저하하였다. 소각재 IA2와 규조분말을 병용하여 혼합하므로써 목표슬럼프를 얻기 위한 고성능감수제의 사용량은 증가하였으나, 재령 28일 압축강도는 향상되는 효과가 있었다. 또한, 압축강도와 인장강도와의 비는 CEB-FIP 코드의 85%~105% 범위내에 있었다. The Quality of municipal solid waste incineration ash (incineration ash) was analyzed for the purpose of the reusing for concrete material. The folwability and strength properties of concrete mixed with incinerator ash were investigated. CaO component was included more than 50% in chemical component of incinerator ash, mean size of 50% accumulated particle distribution of incinerator ash was about $25{\mu}m$. Particle shape of incinerator ash ($IA_1$) was massed the round shape with fine particle, particle shape of incinerator ash ($IA_2$) was piled up the sheet shape according to manufacture procedure. The Quality of concrete was effected by use of incinerator ash. When the incinerator Ash ($IA_2$) was used, slum of concrete was increased and dosage of high range water reducing agent was reduced. However, strength development of concrete was decreased. Dosage of high range water reducing agent was increased by combined use of incinerator ash ($IA_2$) and diatomite powder, but strength development of concrete was improved. Ratio of compressive strength and tensile strength was in the range 85%~105% of CEB-FIP model code.

한국 20대 여성의 성에 대한 태도와 자궁경부암 예방행위와의 관련성 연구

김재우,김성호,강정규,Kim, Jae Woo,Kim, Sung-Ho,Kang, Jung-Kyu 한국학교ㆍ지역보건교육학회 2021 한국학교지역보건교육학회지 Vol.22 No.2

Objective: The purpose of this study is to examine the Korean women's attitude toward sex in their 20s in order to investigate the relationship between attitude toward sex and preventive behavior against cervical cancer. Method: The data was collected by conducting a survey in parts of Chungcheongbuk provinces from November 1st to the 10th, 2017, with a total of 353 respondents. Frequency analysis, chi-square test and logistic-regression analysis were conducted. Result: A result of logistic-regression analysis, the degree of preventive behavior against cervical cancer of those who were 'conservative' toward sex was 1.866 times greater, significantly. As the attitude toward sex becomes more liberal, the awareness of the necessity for preventive behavior against cervical cancer may possibly become lower. Conclusion: Therefore it is necessary to work in tandem with the school health program to increase preventive behavior against cervical cancer for the women in their 20s through early education and promotion.