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모바일 애플리케이션 시장(앱스토어)의 활성화 방안 : 인증 중개를 통한 신뢰도의 향상
백종혁,신민수 한국경영정보학회 2010 한국경영정보학회 학술대회논문집 Vol.2010 No.1
국내 표준 모바일 플랫폼(WIPI)의 탑재 의무화가 폐지되고, 다양한 모바일 플랫폼(Apple의 iPhone 플랫폼, Google의 Android 플랫폼)이 국내에 유입되었다. 이에 따라 모바일 애플리케이션 (Application) 시장구조가 통신사와 단말기 제조사 중심의 수직적인 구조에서 애플리케이션 개발자, 콘텐츠 개발자의 영향력이 확대되고, 모바일 시장에 참여하는 다양한 주체가 서로를 견제하는 수평적인 구조로 변하고 있다. 이러한 상황에서 애플리케이션 인증과 인증의 중개(테스트 연구소가 제공)를 통해 플랫폼 제공자(Platform provider)와 애플리케이션 개발자(Application developer) 사이에서의 중개 역할이 모바일 애플리케이션 시장(앱스토어)의 활성화에 어떠한 영향을 미치는지에 대하여 분석하고자 한다. 연구의 기대 효과로 관리의 주체가 모호하여 사용자에게 신뢰성을 제공할 수 없었던 모바일 애플리케이션 시장에 인증의 도입으로 관리 주체가 명확해지고 애플리케이션 시장의 활성화에 큰 시사점을 제시할 것으로 기대한다.
$UO_2-6wt%Gd_2O_3$ 소결체에서 Al 첨가가 소결성 및 미세조직에 미치는 영향
백종혁,유호식,윤경호,김형수,서금석,Baek, Jong-Hyeok,Yu, Ho-Sik,Yun, Gyeong-Ho,Kim, Hyeong-Su,Seo, Geum-Seok 한국재료학회 1995 한국재료학회지 Vol.5 No.6
The sinterability and the microstructure of Al doped UO$_2$-6wt%Gd$_2$O$_3$pellets, which were doped using Al(OH)$_3$, ADS(aluminium distearate), Al(OH)$_3$+ ADS mixture and sintered at 1$700^{\circ}C$ for 4h in H$_2$, atmospheres, were examined. The sintered densities of Al doped UO$_2$-6wt%Gd$_2$O$_3$pellets were more than 94% T.D.. The open porosity in ADS doped pellets was dramatically decreased. And the amounts of pores less than l${\mu}{\textrm}{m}$ and larger than 10${\mu}{\textrm}{m}$ were decreased regardless of the kinds of doped Al compounds. And the average pore size of Al doped UO$_2$-6wt%Gd$_2$O$_3$pellets was ranged between 2 and 3${\mu}{\textrm}{m}$. While grain structure of non-doped UO$_2$-6wt%Gd$_2$O$_3$pellets was revealed to be duplex type (rocks in sands), that of Al doped pellets to be uniformly equiaxid type. Especially, the grain size in ADS doped pellets was averaged to 4.6${\mu}{\textrm}{m}$. $UO_2$-6wt%Gd$_2$O$_3$가연성 독물질 소결체에 미량첨가한 Al 화합물(Al(OH)$_3$, ADS(aluminium disterate), Al(OH)$_3$+ADS)이 소결성 및 미세조직에 미치는 영향을 고찰하고자 하였다. 이를 위하여 Al이 첨가된 $UO_2$-6wt%Gd$_2$O$_3$압분체를 1$700^{\circ}C$, 수소 분위기에서 4시간동안 소결한 후 특성시험을 수행하였다 Al을 첨가한 $UO_2$-6wt%Gd$_2$O$_3$의 소결밀도는 94% T.D.이상이였고, ADS를 이용한 Al 첨가가 개기공도 감소에 상대적으로 크게 기여하였다. 또한 Al을 첨가하면 10$\mu\textrm{m}$ 이상의 큰 기공과 1$\mu\textrm{m}$ 이하의 작은 기공은 많이 줄어들었고 첨가된 Al 화합물의 종류와는 무관하게 평균 기공크기는 2-3$\mu\textrm{m}$였다. 그리고 Al을 첨가하지 않은 소결체의 결정립은 이중 결정립 형태를 갖는 반면에 Al을 첨가하면 결정립은 균일하였다. 특히, ADS를 첨가한 소결체의 평균 결정립 크기는 4.6$\mu\textrm{m}$로 가장크게 증가하였다.
${UO_2}-{Gd_2}{O_3}$소결체에서 ${Gd_2}{O_3}$첨가가 소결 및 재소결밀도에 미치는 영향
백종혁,Baek, Jong-Hyeok 한국재료학회 1995 한국재료학회지 Vol.5 No.3
ex-AUC U$O_{2}$ 분말과 $Gd_{2}$O_{3}$ 분말을 기계적으로 혼합하여 소결한 U$O_{2}$-$Gd_{2}$O_{3}$ 소결체의 밀도 변화와 재소결 후 밀도변화를 기공크기 및 분포의 변화로 서술하였다. 수소분위기에서 175$0^{\circ}C$, 4시간 동안 소결하였을 때, 순수 U$O_{2}$의 소결밀도는 97.2% T.D.였으나 6wt% $Gd_{2}$O_{3}$ 첨가까지는 U$O_{2}$-$Gd_{2}$O_{3}$의 소결밀도는 $U^{+4}$와 $Gd^{+4}$의 상호확산 때문에 약 90% T.D.로 급격히 감소하였다. 그러나 6wt% 이상의 $Gd_{2}$O_{3}$가 첨가되면 우라늄이온 산화아와 산소침입으로 인하여 소결밀도는 오히려 증가하였다. 1$700^{\circ}C$에서 재소결시킬 때 순수 U$O_{2}$ 소결체에서는 재소결 시간에 따라 밀도증가가 발생하였다. U$O_{2}$-$Gd_{2}$O_{3}$ 소결체 경우에는 재소결시 밀도가 감소하였으나 재소결 시간이 증가함에 따라 다시 밀도는 증가하였고, 6wt%$Gd_{2}$O_{3}$가 첨가된 U$O_{2}$-$Gd_{2}$O_{3}$ 소결체에서 밀도가 가장 많이 감소하였다.
백종혁,김성호,이찬복,한도희 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.4
The mechanical properties and microstructural evolution of modified 9Cr-1Mo steel have been studied to investigate steel property changes after long-term isothermal aging at 600℃ for 50,000 h. The microhardness and strength were maintained constantly after aging but the impact energy was dramatically reduced by 62 % during the aging period. From the viewpoint of microstructural evolution after the aging process, Cr-enrichment and Fe-depletion took place within the M23C6-type precipitates in the as-aged steel and V-depletion also happened within the VX-type precipitates after aging. In addition, the precipitates of the M2Mo-type Laves phase and the segregation of the impurity atoms would be formed during the long-term aging period. It was considered that the sharp reduction of the impact energy could be related to the formation of the Laves phases and the impurity segregation after aging at 600℃. The phase stability was also verified by the specific heat results up to 950℃ from a DSC test. It was concluded from this study that the modified 9Cr-1Mo steel would keep its microstructural stability at 600℃ during the long-term aging period of 50,000 h, which was equivalent to the in-service life of the SFR fuel cladding. The mechanical properties and microstructural evolution of modified 9Cr-1Mo steel have been studied to investigate steel property changes after long-term isothermal aging at 600℃ for 50,000 h. The microhardness and strength were maintained constantly after aging but the impact energy was dramatically reduced by 62 % during the aging period. From the viewpoint of microstructural evolution after the aging process, Cr-enrichment and Fe-depletion took place within the M23C6-type precipitates in the as-aged steel and V-depletion also happened within the VX-type precipitates after aging. In addition, the precipitates of the M2Mo-type Laves phase and the segregation of the impurity atoms would be formed during the long-term aging period. It was considered that the sharp reduction of the impact energy could be related to the formation of the Laves phases and the impurity segregation after aging at 600℃. The phase stability was also verified by the specific heat results up to 950℃ from a DSC test. It was concluded from this study that the modified 9Cr-1Mo steel would keep its microstructural stability at 600℃ during the long-term aging period of 50,000 h, which was equivalent to the in-service life of the SFR fuel cladding.
Zr-0.8Sn-0.4Fe-0.2Cr-xNb 합금계의 중간열처리 온도변화에 따른 부식 특성
白種爀,鄭龍煥,金仁燮 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.3
To investigate the effects of Nb content and annealing parameter on corrosion resistance in Zr-0.8Sn-0.4Fe-0.2Cr-xNb(x=0.1, 0.2, 0.4, 0.8%) alloys, corrosion tests have been carried out under the 400℃ steam condition. The corrosion resistance of the alloys decreased with increasing the Nb content and the accumulated annealing parameter. But the Nb content in precipitates and the hydrogen pick-up fraction in matrix increased when the adding Nb content and the accumulated annealing parameter increased. The fraction of t-ZrO_2 in oxide layers decreased with increasing the accumulated annealing parameter. It was concluded that the corrosion resistance of Zr-0.8Sn-0.4Fe-0.2Cr-xNb alloys could be controlled by the characteristics of (Zr, Nb)(Fe, Cr)_2 type precipitates with the variation of the Nb content and the accumulated annealing parameter.
백종혁,김석봉,손기영,박영준,Baek, Jonghyuk,Kim, Suk Bong,Son, Kiyoung,Park, Young Jun 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.2
Although self-propelled artilleries are mobile equipment, they need their own covered-positions for survival against preemptive strikes. The most important military requirement is enough protective capacity against blast pressure caused by explosion. This paper aims to assess the protective capacity of the newly-placed concrete box-type artillery positions using accurate structural geometric models as well as soil-structure interaction analysis. The commercial program is used to model the structural geometry of the positions. In order to describe the correct wave propagation in the backfill along with soil-structure interaction, used parameters in shock equation of state are selected based on the related studies as well as theories and then their final results are verified with the ones calculated with empirical equations in the US Unified Facility Criteria. In sum, it could be concluded that the protective capacity of the newly-built positions satisfies the protective structural requirement.