• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.263-263
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• 2013

This work examines the dynamic properties of ice surfaces in vacuum for the temperature range of 140~180 K, which extends over the onset temperatures for ice sublimation and the phase transition from amorphous to crystallization ice. In particular, the study focuses on the transport processes of excess protons and chloride ions in ice and their segregative behavior to the ice surface. These phenomena were studied by conducting experiments with a relatively thick (~100 BL) ice film constructed with a bottom $H_2O$ layer and an upper $D_2O$ layer, with excess hydronium and chloride ions trapped at the $H_2O$/$D_2O$ interface as they were generated by the ionization of hydrogen chloride. The migration of protons, chloride ions, and water molecules to the ice film surface and their H/D exchange reactions were measured as a function of temperature using the methods of low energy sputtering (LES) and Cs+ reactive ion scattering (RIS). Temperature programmed desorption (TPD) experiments monitored the desorption of water and hydrogen chloride from the surface. Our observations indicated that both hydronium and chloride ions migrated from the interfacial layer to segregate to the surface at high temperature. Hydrogen chloride gas desorbs via recombination reaction of hydronium and chloride ions floating on the surface. Surface segregation of these species is driven by thermodynamic potential gradient present near the ice surface, whereas in the bulk, their transport is facilitated by thermal diffusion process. The finding suggests that chlorine activation reactions of hydrogen chloride for polar stratospheric ice particles occur at the surface of ice within a depth of at most a few molecular layers, rather than in the bulk phase.

• 한국수산과학회지
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• 제48권4호
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• pp.483-488
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• 2015

We studied oocyte steroidogenesis in the blackfin flounder Glyptocephalus stelleri as a region-specific species, in the East Sea of Korea during the spawning season. Maturing oocytes (0.76, 0.82, 0.88, and 0.91 mm in oocyte diameter) were incubated in vitro in the presence of [$^3H$] $17{\alpha}$-hydroxyprogesterone ($[^3H]17{\alpha}$-OHP) as a precursor. Steroid metabolites were extracted from the incubated medium and oocytes, and the extracts were separated and identified by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and gas chromatographymass spectrometry (GC/MS). The major metabolites produced from $[^3H]17{\alpha}$-OHP were androgens [androstenedione (A4) and testosterone (T)] and estrogens [$17{\beta}$-estradiol (E2) and estrone (E1)] and progestins [$17{\alpha},20{\alpha}$-dihydroxy-4-pregen-3-one ($17{\alpha}20{\alpha}P$) and $17{\alpha}20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$)] in maturing oocytes. The metabolic rate of $17{\alpha}20{\beta}$ was elevated (29.04%) in oocytes measuring 0.88 mm (nucleus migration stage following the induction of germinal vesicle breakdown), but was very low in oocytes measuring 0.76, 0.82, and 0.91 mm (0.42, 0.67, and 2.62%, respectively). From these results, we suggest that $17{\alpha}20{\beta}P$ acts as a maturation-inducing steroid in the blackfin flounder.

• 대기
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• 제18권1호
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• pp.55-70
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• 2008

The global time slice approach is a transient experiment using high resolution atmosphere-only model with boundary condition from the low resolution globally coupled ocean-atmosphere model. The present study employs this "time slice concept" using ECHAM4 atmosphere-only model at a horizontal resolution of T106 with the lower boundary forcing obtained from a lower-resolution (T42) greenhouse gas + aerosol forcing experiment performed using the ECHO-G/S (ECHAM4/HOPE-G) coupled model. In order to assess the impact of horizontal resolution on simulated East Asian summer monsoon climate, the differences in climate response between the time slice experiments of the present and that of IPCC SRES AR4 participating 21 models including coarser (T30) coupled model are compared. The higher resolution model from time slice experiment in the present climate show successful performance in simulating the northward migration and the location of the maximum rainfall during the rainy season over East Asia, although its rainfall amount was somewhat weak compared to the observation. Based on the present climate simulation, the possible change of East Asian summer monsoon rainfall in the future climate by the IPCC SRES A1B scenario, tends to be increased especially over the eastern part of Japan during July and September. The increase of the precipitation over this region seems to be related with the weakening of northwestern part of North Pacific High and the formation of anticyclonic flow over the south of Yangtze River in the future climate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.197-200
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• 2001

In this letter, we report on the investigation of Ni/Si/Ni Ohmic contacts to n-type 4H-SiC. Ohmic contacts have been formed by a vacuum annealing and $N_2$ gas ambient annealing method at $950^{\circ}C$ for 10 min. The specific contact resistivity ( $\rho_{c}$ ), sheet resistance($R_s$), contact resistance($R_c$), transfer length($L_T$) were calculated from resistance($R_T$) versus contact spacing(d) measurements obtained from 10 TLM(transmission line method) structures. The resulting average values of vacuum annealing sample were $\rho_{c}=3.8{\times}10^{-5}\Omega cm^{3}$, $R_{c}=4.9{\Omega}$, $R_{T}=9.8{\Omega}$ and $L_{T}=15.5{\mu}m$, resulting average values of another sample were $\rho_{c}=2.29{\times}10^{-4}\Omega cm^{3}$, $R_{c}=12.9{\Omega}$ and $R_{T}=25.8{\Omega}$. The physical properties of contacts were examined using X-Ray Diffraction and Auger analysis, there was a uniform intermixing of the Si and Ni, migration of Ni into the SiC.

• Food Science and Biotechnology
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• 제18권1호
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• pp.48-52
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• 2009

Eoyukjang is a traditional Korean sauce made of cooked soypaste or meju supplemented with fish and meats at least 1 year of fermentation period. Eoyukjang was recovered according to the traditional method and stored under the ground in a pot without plastic packaging (13G: 13 month fermentation under the ground) or in an incubator wrapped with plastic packaging (6I, 12I, and 18I: 6, 12, and 18 month fermentation, respectively). Distribution of isoflavones and fatty acids were monitored by high performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. Total isoflavones in 13G, 6I, 12I, and 18I were 3.792, 0.387, 0.460, and $0.510{\mu}mol/g$, respectively. Samples of 13G had at least 8.24 times higher isoflavone contents than samples from 12I. Aglycones were the major isoflavones in eoyukjang and were found more than 92% in 13G and 39-63% in incubated samples. In fatty acid analysis, the ratios of unsaturated to saturated fatty acids from 13G were higher than those from 6I, 12I, and 18I. Traditional fermentation methods using a pot may allow more migration of air and moisture than samples wrapped with plastic packaging, which caused the difference in the distribution of isoflavones and fatty acids.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4103-4121
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• 2018

Quality of Service (QoS) awareness is recognized as a key point for the success of Internet of Things (IOT).Realizing the full potential of the Internet of Things requires, a real-time task scheduling algorithm must be designed to meet the QoS need. In order to schedule tasks with diverse QoS requirements in cloud environment efficiently, we propose a task scheduling strategy based on dynamic priority and load balancing (DPLB) in this paper. The dynamic priority consisted of task value density and the urgency of the task execution, the priority is increased over time to insure that each task can be implemented in time. The scheduling decision variable is composed of time attractiveness considered earliest completion time (ECT) and load brightness considered load status information which by obtain from each virtual machine by topic-based publish/subscribe mechanism. Then sorting tasks by priority and first schedule the task with highest priority to the virtual machine in feasible VMs group which satisfy the QoS requirements of task with maximal. Finally, after this patch tasks are scheduled over, the task migration manager will start work to reduce the load balancing degree.The experimental results show that, compared with the Min-Min, Max-Min, WRR, GAs, and HBB-LB algorithm, the DPLB is more effective, it reduces the Makespan, balances the load of VMs, augments the success completed ratio of tasks before deadline and raises the profit of cloud service per second.

• Nuclear Engineering and Technology
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• 제47권1호
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• pp.26-32
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• 2015

During the course of a severe accident in a light water nuclear reactor, large amounts of hydrogen can be generated and released into the containment during reactor core degradation. Additional burnable gases [hydrogen ($H_2$) and carbon monoxide (CO)] may be released into the containment in the corium/concrete interaction. This could subsequently raise a combustion hazard. As the Fukushima accidents revealed, hydrogen combustion can cause high pressure spikes that could challenge the reactor buildings and lead to failure of the surrounding buildings. To prevent the gas explosion hazard, most mitigation strategies adopted by European countries are based on the implementation of passive autocatalytic recombiners (PARs). Studies of representative accident sequences indicate that, despite the installation of PARs, it is difficult to prevent at all times and locations, the formation of a combustible mixture that potentially leads to local flame acceleration. Complementary research and development (R&D) projects were recently launched to understand better the phenomena associated with the combustion hazard and to address the issues highlighted after the Fukushima Daiichi events such as explosion hazard in the venting system and the potential flammable mixture migration into spaces beyond the primary containment. The expected results will be used to improve the modeling tools and methodology for hydrogen risk assessment and severe accident management guidelines. The present paper aims to present the methodology adopted by Institut de Radioprotection et de $S{\hat{u}}ret{\acute{e}}$ $Nucl{\acute{e}}aire$ to assess hydrogen risk in nuclear power plants, in particular French nuclear power plants, the open issues, and the ongoing R&D programs related to hydrogen distribution, mitigation, and combustion.

• 한국과학교육학회지
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• 제31권6호
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• pp.1009-1024
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• 2011

선행연구에 의하면 많은 중 고등학교 학생들과 교사들이 용해와 확산, 확산과 분출을 잘 구분하지 못한다고 하므로 본 연구에서는 이 용어들의 정의로부터 각 개념들을 서로 구분하는 것이 가능한지 알아보고자 하였다. 이를 위해 현재 과학자들이 합의하고 있는 것으로 생각되는 용어의 정의를 IUPAC의 Gold Book과 대학 물리화학 교재로부터 조사하여 비교하였다. 그리고 현행 중 고등학교 교과서 및 대학 일반화학 교재에 서술된 정의를 조사하여 학생들과 교사들이 혼란을 느낄 수 있는 문제점을 파악하고 그 개선점을 알아보고자 하였다. 그 결과 용해는 두 상이 혼합되어 하나의 상이 되는 것임에 비해 확산은 농도 차를 없애는 방향으로 물질이 이동하는 것이므로 서로 구분 가능하다고 생각된다. 그러나 중.고등학교 교과서와 대학 일반화학 교재에서도 대부분 확산을 농도 차에 의한 것으로 명확하게 서술하지 않았는데 이 1022 박종윤를 강조해서 서술할 필요가 있다. 분출은 용기 벽면의 아주 작은 구멍을 통해 기체 입자가 충돌 없이 빠져나가는 것이므로 기체 확산과 분명히 구분되지만 고등학교 교과서에서 분출의 정의를 제시한 교과서는 거의 없었다.

• 지구물리와물리탐사
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• 제18권1호
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• pp.21-30
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• 2015

유발지진은 인류에 의한 수많은 영향 및 다양한 지질학적 조건과 연관되어서 지난 수십 년 동안 관측되어 왔다. 이 논문에서는 다양한 유발지진을 고찰하고 자연적인 조구조 지진뿐만 아니라 유발지진의 종류에 따라 서로 비교한다. 수압파쇄는 암석층에서 새로운 균열을 통해 투수성을 높이는데 보편적으로 사용된다. 이 과정에서 유발지진이 발생하는데, 이 지진은 단열망과 석유/가스의 이동에 관한 중요한 정보를 제공한다. 유사한 방식으로 탄화수소 생산과정이나, 댐 저수지, 채광 활동 또는 폐수 주입 등의 과정에서도 의도하지 않은 유발지진이 발생하며, 이를 이용하여 다양한 수리역학적인 과정과 다양한 규모에서 저류층 특성의 변화를 파악할 수 있다. 일반적인 결론으로 지금까지 알려진 유발지진에 대한 불확실성과 지식의 한계를 요약하고 향후 연구에서 다루어야 할 몇 가지 주제를 제시한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.197-200
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• 2001

In this letter, we report on the investigation of Ni/Si/Ni Ohmic contacts to n-type 4H-SiC. Ohmic contacts have been formed by a vacuum annealing and N$_2$ gas ambient annealing method at 950$^{\circ}C$ for 10 min. The specific contact resistivity($\rho$$\sub$c/), sheet resistance(R$\sub$S/), contact resistance(R$\sub$S/), transfer length(LT) were calculated from resistance(R$\sub$T/) versus contact spacing(d) measurements obtained from 10 TLM(transmission line method) structures. The resulting average values of vacuum annealing sample were $\rho$$\sub$c/=3.8x10$\^$-5/ Ω$\textrm{cm}^2$ , R$\sub$c/=4.9Ω, R$\sub$T/=9.8Ω and L$\sub$T/=15.5$\mu\textrm{m}$, resulting average values of another sample were $\rho$$\sub$c/=2.29x10$\^$-4/ Ω$\textrm{cm}^2$ , R$\sub$c/=12.9Ω, R$\sub$T/=25.8Ω. The Physical properties of contacts were examined using X-Ray Diffraction and Auger analysis, there was a uniform intermixing of the Si and Ni, migration of Ni into the SiC.