• 대한화학회지
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• 제61권1호
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• pp.7-11
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• 2017

The extended $H{\ddot{u}}ckel$ method is employed to analyze the interaction of carbon monoxide with the TiC(001) surfaces, both perfect and containing carbon vacancies. CO exhibits a similar ${\sigma}$-donation interaction for both $Ti_{25}C_{25}$ and $Ti_{25}C_{23}$ clusters, as deduced from the fact that the populations of the CO $5{\sigma}$ orbital are identical upon adsorption, but it bonds more strongly with the $Ti_{25}C_{23}$ than with the $Ti_{25}C_{25}$ because the metal d electron density in $Ti_{25}C_{23}$ provides ${\pi}$ back-bonding interactions with CO that are absent in $Ti_{25}C_{25}$. This work suggests that a difference in reactivity toward CO of stoichiometric TiC and TiC with carbon defects is connected with the occupancy of $2{\pi}^*$ orbitals that leads to a significant weakening of the C-O bond.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1441-1444
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• 2013

Hetero-dimer anions of naphthalene (Np), anthracene (An), phenanthrene (Ph) and pyrene (Py) were investigated using the time-of-flight mass spectrometer (TOF-MS), anion photoelectron spectroscopy (PES) and theoretical calculation. There are two possible geometries with their electron affinity (EA) difference: parallel displaced (PD) and T-shaped. Dispersion force plays a key role in PD structure with the formation of a new anionic core while ${\pi}$-hydrogen interaction plays a key role in T-shaped structure with the monomer anionic core. The optimized structures and charge distributions can simply be explained by the relative difference of EA.

• Bulletin of the Korean Chemical Society
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• 제4권3호
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• pp.123-127
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• 1983

The crystal structure of metoclopramide, $C_14H_22ClN_3O_2$, has been determined by X-ray diffraction techniques using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with Mo $K\alpha$ radiation from a crystal with space group symmetry $P{\overline{1}}$ and unit cell parameters a = 7.500(1), b = 8.707(2), c = 13.292(2) ${\AA}$; ${\alpha}$ = 101.70(2), ${\beta}$ = 81.20(2), and ${\gamma}$ = $114.90(l)^{\circ}$. The sructure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.055 for the 1524 observed reflections. The bent overall-conformation of the molecule seems to be determined mainly by the bifurcated intramolecular hydrogen bond from the amide nitrogen atom to the methoxy oxygen and the amine nitrogen atoms. The crystal packing consists of the hydrogen bonds, ${\pi}-{\pi}$ interaction and hydrophobic interaction.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.101-107
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• 1993

Ab initio calculations are carried out at the 6-311G$^{**}$ level for the $C_{2v}$ interactions of Be and Li atoms with acetylene molecule. The main contribution to the deep minima on the $^3B_2\;BeC_2H_2\;and\;^2B_2 LiC_2H_2$ potential energy curves is the b_2\;(2p(3b_2)-l{\pi}_g^*(4b_2))$ interaction, the $a_1\;(2s(6a_1)-I{\pi}_u(5a_1))$ interaction playing a relatively minor role. The exo deflection of the C-H bonds is basically favored, as in the $b_2$ interaction, due to steric crowding between the metal and H atoms, but the strong in-phase orbital interaction, or mixing, of the $a_1$ symmetry hydrogen orbital with the $5a'_1,\;6a'_1,\;and\;7a'_1$ orbitals can cause a small endo deflection in the repulsive complexes. The Be complex is more stable than the Li complex due to the double occupancy of the 2s orbital in Be. The stability and structure of the $MC_2H_2$ complexes are in general determined by the occupancy of the singly occupied frontier orbitals.

• 대한임상검사과학회지
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• 제39권3호
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• pp.249-255
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• 2007

While respiratory burst enhances neutrophil glucose utilization, many neutrophil functions are critically influenced by extracellular matrix interaction and phosphoinositide-3-OH kinase (PI3K) signaling. We thus evaluated the role of RGD integrin occupancy and PI3K inhibition on respiratory burst and [18F]FDG uptake of stimulated neutrophils. Human neutrophils were stimulated by 100 ng/mL phorbol-myristate-acetate (PMA), and respiratory burst was measured by cumulative luminescence with lucigenin. [18F]FDG uptake and total hexokinase activity was measured 20 min after PMA stimulation in the presence or absence of soluble RGD peptides (200 g/mL) and/or the PI3K inhibitor wortmannin (200 nM). PMA induced a 71.70.9 fold increase in neutrophil oxygen intermediate generation. [18F]FDG uptake was increased to $194.6{\pm} 3.7%$ and hexokinase activity to $145.0{\pm}2.0%$ of basal levels (both p<0.0005). RGD peptides attenuated respiratory burst activation to $35.6{\pm}0.2%$ (p<0.005), but did not inhibit stimulated [18F]FDG uptake or hexokinase activity. In contrast, without affecting respiratory burst activation, wortmannin inhibited PMA stimulated [18F]FDG uptake to $66.9{\pm}1.6%$ and hexokinase activity to $81.0{\pm}4.2%$ (both P<0.0005), demonstrating its dependence on PI3K activity. Neither RGD nor wortmannin reversed the other's inhibitory effect on stimulated [18F]FDG uptake and hexokinase activity or respiratory burst, which suggests the involvement of distinct signaling pathways. Neutrophil [18F]FDG uptake is enhanced by PMA through a mechanism that requires PI3K activity but is independent of integrin receptor occupancy or respiratory burst activation.

• Journal of Advanced Marine Engineering and Technology
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• 제39권9호
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• pp.953-958
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• 2015

라즈베리파이는 복수개의 입출력 주변 장치를 지원할 수 있는 신용카드 크기 정도의 단일보드 컴퓨터로 이기종간 상호연동을 위한 완전한 플랫폼으로 사용할 수 있으므로 다양한 응용에 적용될 수 있다. 라즈베리파이에 와이파이 기능을 결합하면 원격통신이 가능하여 무선센서 노드를 구성하는데도 매우 적합하다. 또한 데이터처리와 의사결정을 인공지능에 기반을 둘 수 있으므로 화재 감시나 화재발생 신뢰도 판단 등과 같은 예제를 이미 개발된 테스트베드에서 수행해 볼 수 있다. 본 논문은 건물 내의 능동적 화재안전감시를 위한 센서 웹노드로서 라즈베리파이 이용에 대한 연구 결과이다. UV 불꽃감지센서가 촛불 크기 정도의 불꽃을 감지하면 라즈베리파이는 GCM 서버를 통해 지정된 스마트폰으로 현장상황을 알리는 푸쉬 메시지를 보낸다. 모바일 앱은 오작동 알람 여부를 판별하기 위한 실시간 비디오 영상을 제공할 수 있도록 개발되었다. 만약 긴급 상황이라면 긴급통화로 즉시 도움을 요청할 수 있도록 구현하였다.

• 대한화학회지
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• 제35권3호
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• pp.196-203
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• 1991

25$^{\circ}$C 때 벤조산과 메타 및 파라위치에 할로겐(F, Cl, Br)이 치환된 $pK_a$값을 메탄올-물 혼합용매(0∼80% 메탄올) 중에서 Fuoss-Kraus 식에 근거한 전도도법과 Gelb의 전도도법을 이용하여 결정하였다. 할로겐 치환기에 따른 벤조산의 $pK_a$ 변화를 전자받게 유도효과와 전자주게 공명효과로 복합시킨 치환기 상수(${\sigma}_1$ 및 ${\sigma}_R$)로써 논의하였다. ${\sigma}_1$가 $D^{-1}$에 대하여 양(+)의 기울기를 갖는 직선성을 보인 반면 ${\sigma}_R$은 $D^{-1}$에 대하여 음(-)의 기울기를 갖는 직선성을 보이고 있는데, 이를 field effect의 유전상수 의존성과 할로겐 치환기의 ${\pi}$-고립쌍 전자와 이온화 중심간의 through-space ${\pi}$-상호작용으로 해석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1258-1260
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• 1998

In this study, we investigated the generation of pretilt angle for nematic liquid crystal (NLC) in a cell with oblique non-polarized ultraviolet (UV) light irradiation on polyimide (PI) surfaces. It was found that the monodomain alignment of the NLC is obtained with an angle of incidence of $70{\sim}85^{\circ}$ on PI surface. We consider that the monodomain alignment of NLC is attributed to anisotropic dispersion force due to photo-depolymerization of polymer on PI surfaces. Also, pretilt angle of NLC is generated about $3^{\circ}$ with an angle of incidence of $70{\sim}75^{\circ}$. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecules and the polymer surfaces.

• BMB Reports
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• 제43권3호
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• pp.199-204
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• 2010

The protein p104 was first isolated as a binding partner of the Src homology domain of phospholipase C$\gamma$1, and has been shown to associate with p85$\alpha$, Grb2. The ectopic expression of p104 reduced cellular growth rate, which was also achieved with the overexpression of only the proline-rich region of p104. The proline-rich region of p104 has been found to inhibit the colony formation of platelet-derived growth factor BB-stimulated NIH3T3 cells and MCF7 cancer cells on soft agar. Mutagenesis analysis showed that the second and third proline-rich regions are essential for growth control, as well as for interaction with p85$\alpha$. Overexpression of p104 increased the level of the cyclin-dependent kinase inhibitor, $p27^{Kip1}$, and inhibited the activity of phosphoinositide 3-kinase (PI3K). In summary, p104 interacts with p85$\alpha$ and is involved in the regulation of $p27^{Kip1}$ expression for the reduction of cellular proliferation.

• Bulletin of the Korean Chemical Society
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• 제7권3호
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• pp.196-200
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• 1986

The solvent change and salt do not affect the fluorescence quantum yield of 1,3-dimethylnaphtho[1,2-e]uracil indicating the considerable energy gap between the lowest singlet $({\pi},\;{\pi}^{\ast})\;and\;(n,\;{\pi}^{\ast})$ states in the compound. The results are consistent with the strong quenching of fluorescence by ethyl iodide. Fluorescence quantum yield is nearly independent of temperature, probably due to the relatively inefficient internal conversion. Unusual spectral difference is observed in isopentane and ethanol at 77K. The temperature dependence of emission in isopentane and in ethanol suggests that the increase of charge transfer character by the conformational change in isopentane leads to the structureless and red-shifted fluorescence, while in ethanol the decrease of the charge transfer character by the hydrogen bonding interaction results in the structured and blue-shifted fluorescence along with phosphorescence at the low temperature. Temperature dependence of emission in poly(methylmethacrylate) matrix indicates that $T_1{\to}S_0$ radiationless decay is an important process responsible for the strong temperature dependence of phosphorescence.