http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Correlation Between Constituent Phase and Weld Metal Properties in Ni-Reduced Duplex Stainless Steel
Youngchai Lee,Jae Hee Lee,Joonoh Moon,Tae‑Ho Lee,Changhee Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8
The intrinsic properties of austenite and ferrite on the mechanical properties and corrosion resistance of the duplex stainlesssteel weld metals was studied by substituting Ni with Mn, N, and Mn + N. The properties of the weldments fabricated throughgas tungsten arc welding (GTAW) were evaluated using tensile test, Vickers hardness, and potentiodynamic polarizationtests. The mechanical properties and corrosion resistance of the constituent phases were measured using nanoindentationand electron probe microanalysis, respectively. The austenite and ferrite phase fractions of the weld metal were maintainedat approximately 50:50, and no harmful phases degraded the properties. Excessive Mn decreased the corrosion resistance; alarge difference in corrosion resistance between austenite and ferrite also decreased the overall corrosion resistance. In thefiller metal in which Ni was replaced with only Mn or N, the austenite became harder than ferrite, as a result cracks initiatedinside the austenite. The tensile test showed that austenite, which became a relatively hard phase compared to ferrite accordingto the chemical composition, increased the yield strength and decreased the elongation of the weld metal.
Camp2Vec: Embedding cyber campaign with ATT&CK framework for attack group analysis
Lee Insup,Choi Changhee 한국통신학회 2023 ICT Express Vol.9 No.6
As the cyberattack subject has expanded from individual to group, attack patterns have become a complicated form of cyber campaigns. Although detecting the attack groups that operated the cyber campaigns is an important issue, complex methods such as deep learning are difficult to use due to the lack of campaign data. This paper proposes Camp2Vec, a lightweight statistics-based embedding for cyber campaigns, enabling attack group detection. The proposed method models a relationship between a campaign and techniques in the ATT&CK® framework as a document and words. Experimental results with expert-labeled datasets prove that Camp2Vec identifies representative attack groups successfully.
Lee, Illjoo,Park, Hyungkwon,Kim, Jaeick,Lee, Changhee Elsevier Sequoia 2016 Surface & coatings technology Vol.307 No.1
<P><B>Abstract</B></P> <P>Heavy steel automotive parts have been replaced with aluminum-based lightweight materials worldwide. In particular, grey cast iron engine blocks, which are very heavy components in vehicles, have been replaced by aluminum-silicon hypoeutectic alloys in order to reduce emissions and fuel consumption. However, aluminum alloys are not able to withstand severe engine cylinder conditions due to their poor mechanical properties. In this study, a Mo blended ferrous coating was fabricated using atmospheric plasma spraying to replace the grey cast iron liner in the automotive cylinder bore. Five fractions of Mo, 0, 5, 10, 15, and 20wt%, with ferrous powder were prepared to investigate the effect of Mo on the microstructure and mechanical properties of coatings. All of the Mo-added coating layers showed significantly improved mechanical properties, such as hardness and wear resistance compared to that of grey cast iron. However, as Mo content exceeded 10wt% of the blend, the tribological properties gradually degraded due to brittle fracture of Mo. As a result, 10wt% Mo blended with ferrous powder provided optimized mechanical properties and can be substitute for grey cast iron liners in the automotive industry.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mo-added ferrous coating to protect the automotive engine was investigated and it showed excellent mechanical properties. </LI> <LI> The Mo fraction was optimized to maximize the tribological property and minimize the amount of Mo. </LI> <LI> The effect of Mo fraction in the coating later was proven by various mechanical property measurements. </LI> <LI> The effect of Mo on fracture mechanism was investigated based on the microstructure analysis. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Outbreak-Related Porcine Epidemic Diarrhea Virus Strains Similar to US Strains, South Korea, 2013
Lee, Sunhee,Lee, Changhee Centers for Disease Control and Prevention 2014 Emerging infectious diseases Vol.20 No.7
<P>In late 2013, outbreaks of porcine epidemic diarrhea virus (PEDV) infection recurred in South Korea. Genetic and phylogenetic analyses showed that isolates from the outbreaks were most closely related to emergent US strains of PEDV. These US strain–like PEDV variants are prevalent in South Korea and responsible for recent outbreaks in the country.</P>
Lee, Seung-Chul,Noh, Yun-Hee,Lee, Sunhee,Choi, Hwan-Won,Yoon, In-Joong,Kang, Shien-Young,Lee, Changhee The Korean Society of Veterinary Science 2018 大韓獸醫學會誌 Vol.58 No.3
The efficacy of the CA-2-MP120 vaccine, a cell culture-attenuated strain of virulent porcine reproductive and respiratory syndrome virus (PRRSV), was assessed in pigs. Despite the persistence of viremia in all vaccinated animals during the immunization period, the virus was not detected in vaccinated pigs following challenge. Furthermore, no pigs in the vaccinated group shed PRRSV nasally, orally or rectally throughout the experiment. Moreover, histopathological lung and lymph node lesions in the immunized group were much milder than those in the unimmunized and challenged group. These results indicated that CA-2-MP120 can provide effective protection against virulent wild-type PRRSV-2.