• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2466-2472
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• 2013

Human immunodeficiency virus type-1 (HIV-1) is a causative agent of Acquired immunodeficiency syndrome (AIDS), which has affected a large population of the world. Viral envelope glycoprotein (gp120) is an intrinsic protein for HIV-1 to enter into human host cells. Molecular docking guided molecular dynamics (MD) simulation was performed to explore the interaction mechanism of heterobiaryl derivative with gp120. MD simulation result of inhibitor-gp120 complex demonstrated stability. Our MD simulation results are consistent with most of the previous mutational and modeling studies. Inhibitor has an interaction with the CD4 binding region. Van der Waals interaction between inhibitor and Val255, Thr257, Asn425, Met426 and Trp427 were important. This preliminary MD model could be useful in exploiting heterobiaryl-gp120 interaction in greater detail, and will likely to shed lights for further utilization in the development of more potent inhibitors.

• 지구물리와물리탐사
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• 제14권3호
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• pp.242-248
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• 2011

균일한 모델에 대하여 해석적인 방법을 적용하여 한반도 남동부의 감쇠상수 고유치를 분리하였다. 해석적인 방법에 의한 이론치와 759 지진자료에 의한 관측치를 다중지연시간창법으로 비교하여 분리를 행하였다. 이전의 연구에서 한반도의 전체 $Q_i^{-1}$과 $Q_s^{-1}$ 값은 매우 낮은 값이 도출되어 지진 안정지대의 값을 반영하는 것으로 풀이된 반면, 한반도 남동부는 비교적 높은$Q^{-1}$값이어서 이는 한반도 타지역에 비해 높은 지진활동도와 연관된 것으로 보인다.

• 한국세라믹학회지
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• 제37권7호
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• pp.632-637
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• 2000

Thermoelectric conversion properties of commercial Fe-Si2 and Fe-Si alloy ingots prepared by RF inductive furnace were investigated. As sintering temperature increased, density of the specimen increased and the phase transformation from metallic phases ($\varepsilon$-FeSi, ${\alpha}$-Fe2Si5) to semiconducting phase (${\beta}$-FeSi2) occurred more effectively. The FeSi phase was detected even after 100hrs of annealing treatment. For the Fesi1.95∼FeSi2.05 specimens prepared by RF inductive furnace, the thermoelectric property improved as the composition of the specimen approached to stoichiometric composition FeSi2. Electrical conductivity of the specimen increased with increasing temperatures showing typical semiconducting behavior. From the electrical conductivity measurements, activation energy in the intrinsic region (above about 700 K) was calculated to be approximately 0.46 eV. In spite of non-doping, the Seebeck coefficient for every specimen exhibited p-type conduction due to Si deficiency. Its maximum value was located at about 475 K, and then decreased abruptly with increasing temperatures. The power factor was governed by the Seebeck coefficient of the specimen more significantly than by electrical conductivity.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.387-392
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• 2018

Static characteristics of SiC (silicon carbide) lateral p-i-n diodes implemented on semi-insulating substrate without an epitaxial layer are inVestigated. On-axis SiC HPSI (high purity semi-insulating) and VDSI (Vanadium doped semi-insulating) substrates are used to fabricate the lateral p-i-n diode. The space between anode and cathode ($L_{AC}$) is Varied from 5 to $20{\mu}m$ to inVestigate the effect of intrinsic-region length on static characteristics. Maximum breakdown Voltages of HPSI and VDSI are 1117 and 841 V at $L_{AC}=20{\mu}m$, respectiVely. Due to the doped Vanadium ions in VDSI substrate, diffusion length of carriers in the VDSI substrate is less than that of the HPSI substrate. A forward Voltage drop of the diode implemented on VDSI substrate is 12 V at the forward current of $1{\mu}A$, which is higher than 2.5 V of the diode implemented on HPSI substrate.

• Journal of Welding and Joining
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• 제28권2호
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• pp.60-65
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• 2010

Although two dimensional axi-symmetric modeling is useful for calculating the residual stresses of a cylindrical weldment such as a core barrel, this conventional axi-symmetric modeling can not express the behavior of shrinkage well in the locally heated weld zone. New technique of two dimensional axi-symmetric modeling using a virtual fixture is suggested to simulate the behavior of dimensional changes in the weld zone during the heating period of the welding. The virtual fixture in the model has a role to restrain the expansion of the high temperature heated region, which simulates equivalent intrinsic restraint effect of the weldment. In the restraint condition of the virtual fixture above the critical yield strength, the calculated shrinkages by using the suggested axi-symmetric model agreed well with those measured in a welded mock-up. The calculated residual stresses by using the suggested axi-symmetric model also agreed well with those calculated by using conventional axi-symmetric model which has beenused for calculating residual stresses in the weldment.

• 한국지구과학회지
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• 제40권1호
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• pp.1-8
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• 2019

Although recent reports suggest that the negative correlation between the Arctic Oscillation (AO) and the East Asian winter monsoon (EAWM) has been strengthened, it is not clear whether this intermittent relationship is an intrinsic oscillation in the climate system. We investigate the oscillating behavior of the AO-EAWM relationship at decadal time scales using the long-term (500-yr) climate model simulation. The results show that ice cover over the East Siberian Seas is responsible for the change in the coupling strength between AO and EAWM. We found that increased ice cover over these seas strengthens the AO-EAWM linkage, subsequently enhancing cold advection over the East Asia due to anomalous northerly flow via a weakened jet stream. Thus, this strengthened relationship favors more frequent occurrences of cold surges in the EAWM region. Results also indicate that the oscillating relationship between AO and EAWM is a natural variability without anthropogenic drivers, which may help us understand the AO-EAWM linkage under climate change.

• Advances in nano research
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• 제16권1호
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• pp.91-109
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• 2024

Carbon nanotubes are drawing wide attention of research communities and several industries due to their versatile capabilities covering mechanical and other multi-physical properties. However, owing to extreme operating conditions of the synthesis process of these nanostructures, they are often imposed with certain inevitable structural deformities such as single vacancy and nanopore defects. These random irregularities limit the intended functionalities of carbon nanotubes severely. In this article, we investigate the mechanical behaviour of double-wall carbon nanotubes (DWCNT) under the influence of arbitrarily distributed single vacancy and nanopore defects in the outer wall, inner wall, and both the walls. Large-scale molecular simulations reveal that the nanopore defects have more detrimental effects on the mechanical behaviour of DWCNTs, while the defects in the inner wall of DWCNTs make the nanostructures more vulnerable to withstand high longitudinal deformation. From a different perspective, to exploit the mechanics of damage for achieving defect-induced shape modulation and region-wise deformation control, we have further explored the localized longitudinal and transverse spatial effects of DWCNT by designing the defects for their regional distribution. The comprehensive numerical results of the present study would lead to the characterization of the critical mechanical properties of DWCNTs under the presence of inevitable intrinsic defects along with the aspect of defect-induced spatial modulation of shapes for prospective applications in a range of nanoelectromechanical systems and devices.

• 대한전자공학회논문지SD
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• 제38권5호
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• pp.329-337
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• 2001

고유전 (Ba, Sr)TiO/sub 3/ (BST) 박막을 이용한 DRAM storage capacitor의 저전계 영역에서의 전하손실을 발생시키는 커패시터의 누설전류는 유전완화전류와 진성 누설전류로 이루진다고 알려져 있다. 특히, 기가급 DRAM의 동작 전압(~IV)에서 유전완화전류가 진성 누설전류에 비해 훨씬 크기 때문에 이에 대한 심도 있는 연구가 필요하다. 본 연구에서는 thermally stimulated current (TSC) 측정법을 BST 박막에 처음으로 적용하여 트랩의 에너지 level 및 공정변화에 따른 트랩 밀도의 상대적 평가를 하였다. 그리고, 기존에 사용되던 전류-전압(I-V) 측정이나 전류-시간(I-t) 측정과 비교 및 분석함으로써 유전완화 전류의 원인을 규명하고 TSC 측정법의 신뢰성을 살펴보았다. 먼저 안정적인 TSC 측정을 위해 전계, 시간, 온도 및 승온속도에 따른 polarization condition을 알아보았다 이 조건을 이용한 TSC 측정으로부터 BST 박막에서의 트랩의 energy level이 0.20(±0.01) eV와 0.45(±0.02) eV임을 알 수 있었다. Rapid thermal annealing (RTA)을 이용한 후속 열처리에 따른 TSC 측정을 통하여 이 트랩들이 산소결핍(oxygen vacancy)에 기인함을 확인할 수 있었다. MIM BST 커패시터의 열처리에 대한 TSC 특성은 전류-전압(I-V) 및 전류-시간(I-t) 특성과 같은 경향성을 보인다. 이것은 TSC 측정이 BST 박막내의 트랩을 평가하는데 있어서 매우 효과적인 방법이라는 것을 보여준다.

• 한국응용곤충학회지
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• 제41권3호
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• pp.205-209
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• 2002

주홍날개들명나방(Udea ferrugalis)의 온도별(10, 15, 18, 20, 23, 25, 27, 3$0^{\circ}C$) 발육과 생식에 미치는 은도영향에 대하여 조사하였다. 난, 유충, 용기간은 고온에서 짧은 경향이었고, 1$0^{\circ}C$에서는 난과 용 발육은 완료되지 않았다. 각 태별 발육영접온도는 난이 9.5$^{\circ}C$, 유충 9.6$^{\circ}C$ 그리고 용은 11.9$^{\circ}C$이었고, 유효적산온도는 각각 87.9, 200.9, 119.7일도이었다. 산란전기간과 성충수명은 15$^{\circ}C$에서 10.9일, 25.2일이었으나, 23$^{\circ}C$에서는 2.5일, 7.3일, 3$0^{\circ}C$에서는 1.7일, 5.3일로써 온도가 높아질수록 그 기간이 짧았다. 평균산란수는 2$0^{\circ}C$와 23$^{\circ}C$에서 가장 많았다. 세대당 순증식율은 (Ro) 2$0^{\circ}C$에서 265.4로써 가장 높았고, 내적자연증가율은(r$_{m}$ ) $25^{\circ}C$에서 0.247로 가장 높았다. 이 결과로써 주흥날개들명나방의 발육과 생식에 적합한 온도는 2$0^{\circ}C$에서 23$^{\circ}C$이었다.

• 벤처창업연구
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• 제9권2호
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• pp.129-146
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• 2014

조직이 급변하는 경제환경에서 성공하기 위해서는 연구개발만이 아니라 가치사슬 전부분에 걸쳐 혁신적이어야 한다. 특히 중소벤처기업의 경우 새로운 수익을 창출하기 위해서는 가치사슬 전부분에서 혁신적이야 한다. 가치혁신을 위해서는 가치혁신을 일으키는 의미있는 업무, 위험감수성, 고객지향성, 신속한 의사결정, 비즈니스 인텔리전스, 열린 의사소통, 임파워먼트, 사업계획, 학습조직 같은 요소들이 조직문화에 녹아들어야 한다. 본 연구에서는 위의 9가지 요소들을 가치혁신문화로 보고, 이러한 가치혁신문화가 개인창의성에 미치는 영향을 실증적으로 분석하였으며, 결과는 다음과 같다. 첫째, 개인창의성의 구성요인인 전문지식에 정(+)의 영향을 주는 요인으로 의미있는 업무와 임파워먼트, 위험감수성으로 나타났다. 둘째, 창의적 사고기술에 정(+)의 영향을 주는 요인은 열린 조직으로 확인되었다. 셋째, 내적 동기부여에 정(+)의 영향을 미치는 요인으로는 학습조직, 임파워먼트, 혁신성으로 나타났다. 이러한 연구결과를 통해 종업원 개인이 인지한 가치혁신문화는 개인창의성을 유발시키는데 도움이 되는 것을 확인 할 수 있었다.