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인터넷 생존성 및 안정성 강화를 위한 대책 및 복구 방안
백종혁(Baek Jong Hyuk),최영준(Choi Young Jun),정선화(Jung Sun Hwa),박석천(Seok Cheon Park) 한국멀티미디어학회 2006 한국멀티미디어학회 학술발표논문집 Vol.2006 No.2
인터넷이 국내에 첫 선을 보인 이후 국내 인터넷 망 시장은 급속히 성장해 2005년 기준으로 인터넷 이용자가 3,200만 명을 넘어서고 있으며 인터넷 이용자 1인당 평균 2개 이상의 이메일을 보유하게 되었다. 인터넷 서비스사업자(ISP Internet Service Provider) 또한 지속적인 증가로 1999년 초 26개였던 ISP가 1999년 말에는 2배에 달하는 54개로 증가했으며 2005년 말에는 80여 개 이상으로 증가하고 있다. 이와 같은 인터넷 이용자의 급격한 증가와 다수의 인터넷 서비스 사업자의 등장으로 인터넷 트래픽이 급격하게 증기하고 있으나 태풍, 지진 등의 재난재해로 인한 통신대란 또는 『1.25 인터넷 대란』 과 같은 국가적 통신 재난 발생시 효율적인 대책 및 복구방 안은 미비한 상태이다. 따라서 본 논문에서는 인터넷의 생존성, 안정성 강화를 위하여 기존 인터넷 망간 장애 상황을 조사하고 망간 연동 장애 발생 시 사회적 경제적인 문제점을 분석한 후 비 상시 중단 없는 서비스를 위하여 인터넷 생존성 및 안정성을 위한 방안을 제안하였다.
고연소도 신형 Zr피복관의 미세조직과 기계적 특성에 미치는 열처리 및 중서자 조사의 영향
백종혁 ( Jong Hyuk Baek ),김현길 ( Hyun Gil Kim ),정용환 ( Yong Hwan Jeong ) 한국열처리공학회 2004 熱處理工學會誌 Vol.17 No.3
N/A The changes of microstructural and mechanical properties were evaluated for the high bum-up fuel claddings after the neutron irradiation of 1.8-3.1×10^(20)n/㎠ (E>1.O MEV) in HANARO research reactor. After the irradiation, the spot-type dislocations (a-type dislocations) were easily observed in most claddings, and the density of the dislocations was different depending on the grains and was higher at grain boundaries than within grains. As the final annealing temperature increased, the density of spot-type dislocations increased and the line-type dislocations (c-type dislocations) which was perpendicular to the <0002> direction, appeared sporadically in some claddings. However, the types of precipitates in the fuel claddings after the irradiation were not changed from that in unirradiated claddings. The mechanical properties including the hardness, strength and elongation after the irradiation were changed due to the formation of spot-type dislocations. That is, the increase in hardness and strength as well as the decrease in elongation after the irradiation was occurred simultaneously with increasing the final annealing temperature. Owing to the Nb contribution to the formation of spot-type dislocation during the irradiation, the increase in hardness and strength in higher Nb-contained Zr alloys after the irradiation was higher than that in lower Nb-contained Zr alloys.
탄탈륨 함유 9%Cr 페라이트/마르텐사이트 강의 미세조직 및 기계적 특성
백종혁 ( Jong Hyuk Baek ),한창희 ( Chang Hee Han ),김성호 ( Sung Ho Kim ),이찬복 ( Chan Bock Lee ),한도희 ( Do Hee Hahn ) 대한금속재료학회 ( 구 대한금속학회 ) 2009 대한금속·재료학회지 Vol.47 No.4
It was evaluated that the microstructural and mechanical properties of Ta-bearing 9Cr-0.5Mo-2W ferritic/martensitic experimental steels. All the experimental steels showed the tempered martensitic microstructures, and M23C6 carbides, whose sizes were ranged from 200 to 300 nm, were easily observed at both boundaries of the prior austenite grain and the martensite lath. In addition, a relatively large Nb-rich MX carbonitrides were intermittently detected at the prior austenite grain boundaries, whereas a lot of V-rich MX carbonitrides, whose mean diameter was less than 50 nm, were observed randomly at both boundaries. Ta was mainly incorporated into the V-rich MX carbonitrides rather than the Nb-rich ones and their content was spanned from 5 to 20 at.%. Ta contents within the MX precipitates also increased as the content of Ta increased. Because the Ta addition into the steels would be attributed to the precipitation strengthening, solid solution strengthening and lath width reduction, it was shown that the mechanical properties, including hardness, tensile strength and creep rate of the 9%Cr-0.5Mo-2W steels were improved by the increase of Ta content. Especially, 9Cr-0.5Mo-2W-0.3V-0.05Nb-0.14Ta steel was revealed to be relatively excellent in the application for the SFR fuel cladding.
N<sub>2</sub>O 반응 가스를 주입한 RF Reactive Magnetron Sputtering에 의한 ZrO<sub>2</sub> 박막의 구조 및 부식특성 연구
지승현,이석희,백종혁,김준환,윤영수,Jee, Seung-Hyun,Lee, Seok-Hee,Baek, Jong-Hyuk,Kim, Jun-Hwan,Yoon, Young-Soo 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.1
A $ZrO_2$ thin film as a corrosion protective layer was deposited on Zircaloy-4 (Z-4) clad material using $N_2O$ as a reactive gas by RF reactive magnetron sputtering at room temperature. The Z-4 substrate was located in plasma or out of plasma during the $ZrO_2$ deposition process to investigate mechanical and corrosive properties for the plasma immersion. Tetragonal and monoclinic phases were existed in $ZrO_2$ thin film immersed in plasma. We observed that a grain size of the $ZrO_2$ thin film immersed in plasma state is larger than that of the $ZrO_2$ thin film out of plasma state. In addition, the corrosive property of the $ZrO_2$ thin films in the plasma was characterized using the weight gains of Z-4 after the corrosion test. Compared with the $ZrO_2$ thin film immersed out of plasma, the weight gains of $ZrO_2$ thin film immersed in plasma were larger. These results indicate that the $ZrO_2$ film with the tetragonal phase in the $ZrO_2$ can protect the Z-4 from corrosive phenomena.
공개키기반 u-Healthcare 전송 시스템의 구현 및 테스트
정선화 ( Sun Hwa Jung ),백종혁 ( Jong Hyuk Baek ),박석천 ( Seok Cheon Park ) 한국정보처리학회 2006 한국정보처리학회 학술대회논문집 Vol.13 No.1
u-Healthcare는 의료 장비 및 센서 등을 이용하여 획득된 생체 신호 및 의료정보를 유·무선의 통신수단을 통해 지식 기반의 의료정보로 구축하고 이를 언제, 어디서, 누구든지 이용 가능한 실시간 u-Healthcare 지원 환경을 구축하여 지능형 의료정보 웹 포털 서비스를 제공하는데 목적을 두고 있는 서비스이다. 하지만 현시점에서의 시스템은 생체 신호 및 의료 정보 제공시에 보안에 대한 고려가 이루어지고 있지 않다. 이러한 자원들은 개인 프라이버시에 직결되는 것으로 보안의 필요성이 대두된다. 따라서 본 논문에서는 IP망에서 생체신호 전송을 위한 전송시스템을 설계하고 전송시 생체신호정보에 대해 사용자 인증과 암호화를 적용하여 u-Healthcare 전송시스템을 설계하고 구현하였다.
응력이완 열처리된 지르코늄 피복관의 부식 및 인장특성에 미치는 수소화물 영향 평가
방제건 ( Je Geon Bang ),백종혁 ( Jong Hyuk Baek ),이명호 ( Myung Ho Lee ),정용환 ( Yong Hwan Jeong ) 한국열처리공학회 2004 熱處理工學會誌 Vol.17 No.6
N/A The hydrides in cladding affect the corrosion and tensile properties. In this study corrosion and tensile properties were evaluated with varying the hydrogen concentration. The charged hydrogen contents were ranged from 200 to 1000 ppm. The corrosion rate in water and LiOH solution increases with the hydrogen concentration. The hydride did not affect the corrosion mechanism in the pre-transition region, but in the post-transition region the corrosion rate was accelerated. Cladding E contained higher Niobium content was slowly accelerated compared with other claddings. The yield and ultimate strengths were independent on the hydrogen content. How-ever, the total elongation decreased gradually with increasing the hydrogen content. SEM observation of fracture surface showed that an average depth of voids decreased with increasing the hydrogen content and small secondary cracks were observed.
열간가공이 9Cr-1Mo강의 기계적 성질과 미세조직에 미치는 영향
김준환 ( Jun Hwan Kim ),백종혁 ( Jong Hyuk Baek ),한창희 ( Chang Hee Han ),김성호 ( Sung Ho Kim ),이찬복 ( Chan Bock Lee ),나광수 ( Kwang Su Na ),김성주 ( Seong Ju Kim ) 대한금속·재료학회 2009 대한금속·재료학회지 Vol.47 No.10
Thermomechanical processes were carried out to evaluate their effects on the mechanical and the microstructural property of a ferritic-martensitic steel. Modified 9Cr-1Mo steels were hot-rolled at a temperature of either 780℃ or 850℃ after normalizing at 1050℃ and then were air-cooled. Continuous annealing at 850℃ for 2 hours immediately after the hot rolling was also performed and they were compared to the specimens without thermomechanical process. The result showed that there were little differences between the hot rolled specimens in terms of the precipitation density and size. However, V content inside the MX precipitates increased in the case of the specimen rolled at 850℃. The application of the continuous annealing induced coarsening of the Nb-rich MX precipitation as well as an increase in the amount of V-rich MX precipitation, which is expected to enhance high temperature mechanical properties of the ferritic-martensitic steel.
Cu 첨가된 Zr-Nb계 합금에서 열처리조건이 미세조직과 내식성에 미치는 영향
최병권 ( Byung Kwon Choi ),백종혁 ( Jong Hyuk Baek ),정용환 ( Yong Hwan Jeong ) 한국열처리공학회 2004 熱處理工學會誌 Vol.17 No.4
N/A The effects of the cooling and annealing conditions on the microstructures and corrosion properties were investigated for the Cu-contained Zr-Nb alloy (Zr-1.1Nb-0.07Cu). After annealing at 1050℃ for 15 min, the specimens were cooled by three methods of water quenching, air cooling, and furnace cooling. Widmanstatten structures were developed in both air- and furnace-cooled specimens, and the Widmanstatten plate width of the furnace-cooled specimens was wider than that of the air-cooled ones. The weight gain in the furnace-cooling case was higher than that in the air-cooling case. This could be the reason why the diffusion time was more enough during the furnace cooling than the air cooling. The oxide of the furnace-cooled specimen was nonunformly formed just beneath the Widmanstatten plate boundaries, where ß_(Zr) phases were exised concentrately. Compared with the 640℃ annealing after the water quenching, the 570℃ annealing could make the ß_(Nb) phases and a concomitant reduction of the Nb in the matrix, and then it could improve the corrosion resistance with the increase of the annealing time. It would be concluded that the corrosion resistance of the Zr-1.1 Nb-0.07Cu was good when the Nb concentration in the matrix was reached at an equilibrium level and then the ß_(Nb) phase was formed.
란탄족 원소와 Ferritic-Martensitic 강의 반응 거동
김준환 ( Jun Hwan Kim ),백종혁 ( Jong Hyuk Baek ),이병운 ( Byoung Oon Lee ),이찬복 ( Chan Bock Lee ),윤영수 ( Young Soo Yoon ) 대한금속재료학회 ( 구 대한금속학회 ) 2010 대한금속·재료학회지 Vol.48 No.8
A study has been carried out to evaluate the interaction behavior between a lanthanide element and clad material in order to analyze the effect of the lanthanide element on the fuel cladding chemical interaction (FCCI). A diffusion couple test between Misch metal (70Ce-30La) and ferritic-martensitic steel (Gr.92) was performed at 660℃, followed by a microstructural analysis of the coupled sample. The results showed that Ce in the Misch metal, rather than La, reacted with the ferritic-martensitic steel (FMS) to form an interaction layer that penetrated the clad thickness. Fe diffused outside the clad interface to form an Fe2Ce compound, leaving a depletion of Fe caused by excess diffusion as well as by the formation of Cr-rich precipitation inside the interaction layer. The rate of growth followed the cubic rate law, which indicated that Fe depletion was caused by the diffusion of Fe and that the associated Cr-rich phase formation controlled the whole diffusion process.