• 한국융합학회논문지
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• 제8권9호
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• pp.199-209
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• 2017

본 연구는 줄기세포분야의 융합연구 형태와 각 영역별 연구자의 역할을 확인하기 위해 사회네트워크분석을 수행하였다. 자료는 PubMed 데이터베이스에서 1996년부터 2012년까지 만능유도줄기세포와 배아줄기세포를 주제로 발표된 270편의 논문과 성체줄기세포와 중간엽줄기세포 영역의 580편 논문을 추출하였다. 각 영역의 논문에서 공저자 515명과 1,515명을 추출하여 분석하였다. 분석 방법은 사회네트워크분석으로 연결정도중심성, 매개중심성을 확인하고 공저자 네트워크를 구현한 후 연구자의 역할을 확인하였다. 분석결과 공저자 네트워크 상 성과가 높은 핵심 연구자와 중개 연구자를 확인할 수 있었다. 핵심 연구자는 연결정도중심성은 높지만 매개중심성이 높지 않을 수 있으며, 연결정도중심성은 낮으나 매개중심성이 높아 연구자를 연결시키는 중개 연구자를 확인하였다. 공저자 네트워크분석은 분야별 핵심 연구자를 찾아 공동연구를 수행하여 성과를 향상시키고, 연구개발과제 심사를 위한 분야별 전문가 추천을 위한 객관적 자료로 활용이 가능할 것이다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.40-45
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• 1996

A new concept of equivalent homogenization is proposed. The concept employs new set of homogenized parameters: homogenized cross sections (XS) and interface matrix (IM), which relates partial currents at the celt interfaces. The idea of interface matrix generalizes the idea of discontinuity factors (DFs), proposed and developed by K.Koebke and K.Smith. The method of K.Smith can be simulated within framework of new method, while the new method approximates heterogeneous cell better in case of the steep flux gradients at the cell interfaces. The attractive shapes of new concept are: improved accuracy, simplicity of incorporation in the existing codes, equal numerical expenses in comparison to the K.Smith's approach. The new concept is useful for: (a) explicit reflector/baffle simulation; (b) control blades simulation; (c) mixed UO2/MOX core simulation, The offered model has been incorporated in the finite difference code and in the nodal code PANBOX. The numerical results show good accuracy of core calculations and insensitivity of homogenized parameters with respect to in- core conditions.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1084-1096
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• 2023

On-the-fly(OTF) generation of Spectral Superhomogenization(SSPH) factors is analyzed in the multigroup(MG) whole core calculation employing pin-wise continuous energy(CE) slowing-down solutions. The motivation for the work is to avoid the huge computing time required for the generation of a parametrized SSPH factor library(PSSL) which is used to resolve the angular dependency of MG resonance cross sections, and also to exploit the advantage of flexible choice of a MG structure by using CE slowing-down solutions. Two pin-wise CE slowing-down methods, the equivalent Dancoff cell method and the shadowing effect correction method, are evaluated with the OTF SSPH method. The effectiveness of the OTF SSPH method is examined for various simplified and realistic core problems with various MG structures. It is demonstrated that the computing time overhead of this method is negligible whereas the solution accuracy is considerably enhanced.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.243-247
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• 2005

This paper describes an on-going national R&D program for the development of a gas turbine/fuel cell hybrid power generation system and related R&D activities. The final goal of this program is to develop a 200kW-c1ass gas turbine/fuel cell hybrid power generation system and achieve high efficiency over $60\%$ (AC/LHV). In the first phase of the development, a sub-scaled 60kW-class hybrid system based on the 50kW-class microturbine and the 5kW SOFC will be developed for the purpose of concept proof of the hybrid system. Core components such as the microturbine and the SOFC system are being developed and parallel preparation for system integration is being carried out. Before the core components are assembled in the final system. operating characteristics of a hybrid system are investigated from a simulated system where a turbocharger (microturbine simulator) and a modified fuel cell burner test facility (fuel cell simulator) are employed. The 60kW demonstration unit will be built up and operated to provide the valuable information for the preparation of the final full scale 200kW hybrid system.

• 생명과학회지
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• 제16권4호
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• pp.699-703
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• 2006

옥수수(Zea mays)는 단성화 식물로서 암꽃과 수꽃이 한 식물체내에 분리되어서 존재하며 수정시 이질성을 높이는 방향으로 진화되었다. 암꽃과 수꽃 각각은 단성화 상태로 분화하기 전에 한 개의 암술과 세 개의 수술 원시세포가 동일하게 형성된다. 옥수수가수꽃으로 분화할 때는 암술 원시세포에서 세포사멸 현상이 일어나는데 이것은 TASSELSEED 유전자들에 의해 매개된다. 이와 대조적으로 암꽃의 암술에서는 TASSELSEED 유전자들에 의한 세포사멸이 억제되는데 여기에는 SILKLESS1 유전자가 관여한다. 한편, 암꽃의 수술에서는 세포주기 멈춤 현상이 오랜 시간 지속되다가 결국에는 수술이 죽게 된다. 이때 세포주기를 조절하는 유전자인 CYCLIN B 와 WEE1 유전자가 이 과정에 참여한다. 이와 더불어, 지베렐린 생합성의 시간적 공간적 조절이 수술의 세포주기 멈춤의 원인이 된다. 본 총설에서는 옥수수의 성 결정 과정 중에 일어나는 세포사멸, 세포 방어, 세포주기 멈춤에 대하여 분자세포 발생 생물학 및 유전학적인 견지에서 고찰하였다.

• IMMUNE NETWORK
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• 제8권1호
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• pp.1-6
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• 2008

Apoptosis signal-regulating kinase 1 (ASK1), a mitogen- activated protein kinase kinase kinase, plays pivotal roles in stress responses. In addition, ASK1 has emerged as a key regulator of immune responses elicited by pathogen-associated molecular patterns (PAMPs) and endogenous danger signals. Recent studies have demonstrated that reactive oxygen species (ROS)-dependent activation of ASK1 is required for LPS-stimulated cytokine production as well as extracellular ATP-induced apoptosis in immune cells. The mechanism of ROS-dependent regulation of ASK1 activity by thioredoxin and TRAFs has been well characterized. In this review, we focus on the molecular details of the activation of ASK1 and its involvement in innate immunity.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.377-383
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• 2019

Targeting at simulating the application of thorium-uranium (TU) fuel in the CANDU-6 reactor, this paper analyzes the process using the code DRAGON/DONJON where the discrete TU fuel pins are applied in the CANDU-6 reactor under the time-average equilibrium refueling. The results show that the coolant void reactivity of the assembly analyzed in this paper is lower than that of 37-element bundle cell with natural uranium and 37-element bundle cell with mixed TU fuel pins; that the max time-average channel/bundle power of the core meets the limits - less than 6700kW/860 kW; that the fuel conversion ratio is higher than that of the CANDU-6 reactor with natural uranium; and that the exit burnup increases to 13400 MWd/tU. Thus, the simulation in this paper with the fuel in the 37-element bundle cell using discrete TU fuel pins can be considered to be applied in CANDU-6 reactor with adequate modifications of the core structure and operating modes.

• Steel and Composite Structures
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• 제46권4호
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• pp.525-538
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• 2023

This paper focuses on the energy absorption of lattice core sandwich structures of different configurations. The diamond lattice unit cell, which has been extensively investigated for energy absorption applications, is the starting point for this research. The energy absorption behaviour of sandwich structures with an expanded metal sheet as the core is investigated at low-velocity impact loading. Numerical simulations were carried out using ABAQUS/EXPLICIT and the results were thoroughly compared with the experimental results, which indicated desirable accuracy. A parametric analysis, using a Box-Behnken design (BBD), as a method for the design of experiments (DOE), was performed. The samples fabricated in three levels of parameters include 0.081, 0.145, and 0.562 mm² Cell sizes, and 0, 45, and 90-degree cell orientation, which were investigated. It was observed from experimental data that the angle of cells orientation had the highest degree of influence on the specific energy absorption. The results showed that the angle of cells orientation has been the most influential parameter to increase the peak forces. The results from using the design expert software showed the optimal specific energy absorption and peak force to be 1786 J/kg and 26314.4 N, respectively. The obtained R2 values and normal probability plots indicated a good agreement between the experimental results and those predicted by the model.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.373-379
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• 2006

Fiber characteristics and fiber distribution of thermomechanical pulp(TMP), bisulfite chemithermomechanical pulp(bisulfite CTMP), neutral sulfite chemithermomechanical pulp(neutral sulfite CTMP) from kenaf(Hibiscus cannabinus L., Malvaceae) cultivar Tainug-2 cultivated in the reclaimed land of Korea were examined to use effectively nonwood fibers as an alternative raw material sources for papermaking. Yields of TMP and CTMP from kenaf were lower than those of TMP from hardwoods and CTMP from softwoods and hardwoods. Bark fibers of kenaf cultivar Tainung-2 ranged 2.04 to 2.30 mm long and $18.7{\sim}19.7{\mu}m$ width. Core fibers averaged 0.63 to 0.80 mm long and $29.5{\sim}31.4{\mu}m$ wide. Coarseness of bark fiber was higher than that of core fiber, and fiber from TMP were higher than those from both bisulfite CTMP and neutral sulfite CTMP. Curl indexes of bark fibers were higher than those of core fibers. However curl indexes were not significantly affected by the pulping conditions. Short fiber distributions were higher in core fibers from TMP and CTMP and long fiber distributions were higher in bark fibers. There was no significant difference in fiber distribution of whole and core fibers obtained from TMP and CTMP, Fibers from neutral sulfite CTMP, however, exhibited a little higher long fiber distribution. Distinct difference in anatomical characteristics was found between core and bast fibers of kenaf plant. Parenchyma cell, pith parenchyma cell and vessel were observed in core fibers and bast fiber in bast sections.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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• pp.136-136
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• 2005