• Bulletin of the Korean Chemical Society
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• 제27권12호
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• pp.2051-2054
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• 2006

The molecular structures of the ground and lowest triplet states of 2,3-diazabicyclo[2.2.1]hept-2-ene (DBH), 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) and their fused ring derivatives are investigated with an ab initio method and the density functional theory. Unlike the singlet DBH and DBO, the azo skeletal structures of the triplet counterparts are turned out to be quite sensitive to the change of the electronic structure of the fused ring. The B3LYP C-N=N-C dihedral angles of the triplet DBH and DBO are estimated to be about 28.0 and $40.4{^{\circ}}$, respectively. The B3LYP singlet-triplet energy gaps for DBH and DBO are predicted to be 58.4 and 48.4 kcal/mol, respectively. The triplet state energy can be lowered drastically by the presence of the remote $\Pi-\Pi$ interaction as in the case of 1bb'.

• 한국전자파학회논문지
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• 제24권12호
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• pp.1120-1127
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• 2013

본 논문에서는 칩온웨이퍼(Chip on Wafer: CoW) 공정기술을 이용한 새로운 칩온칩(Chip on Chip: CoC) 플립칩 범프 구조들을 제안하여 설계, 제작하고, 초고주파 영역에서의 응답 특성을 분석하였다. Cu 필러(Pillar)/SnAg, Cu 필러/Ni/SnAg의 기존 범프들, 그리고 SnAg, Cu 필러/SnAg, Cu 필러/Ni/SnAg를 Polybenzoxazole(PBO)로 보호한 새로운 범프들을 구성하여 웨이퍼의 $2^{nd}$ Polyimide(PI2) 층의 도포 유무에 따라 10가지 형태의 CoC 샘플들을 구조 설계하였고, 20 GHz까지의 주파수 특성이 고찰되었다. 측정 결과를 고려할 때 PI2 층이 도포된 소자들이 본 실험에 사용된 배치 플립칩 공정에 더 적합함을 알 수 있었고, 18 GHz에서 평균 0.14 dB의 삽입 손실을 보였다. 미세 패드 간격을 가지는 칩의 패키지 용도로 새로 개발된 범프들의 삽입 손실(0.11~0.14 dB)은 기존 범프들의 삽입 손실(0.13~0.17 dB)과 비교해 18 GHz까지 유사한 성능을 보이거나, 다소 좋은 특성을 보여 높은 집적도를 요구하는 다양한 초고주파 패키지에 활용될 수 있음이 확인되었다.

• Bulletin of the Korean Chemical Society
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• 제14권3호
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• pp.320-322
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• 1993

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.235-240
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• 2007

Molecular structures were optimized for the 1,3-diethoxycalix[4]crown-5-ether (2) in the various isomers and their potassium-ion complexes by using B3LYP/6-31+G(d,p)//B1LYP/6-31G(d,p) method after ab initio RHF/6-31G calculation. The cone-shaped isomer of 2 with cr-binding mode has shown the strongest binding efficiency among the six different complexes attributed to seven electrostatic interactions between the potassium cation and the oxygen atoms of crown-5-ether and ethoxy groups of the host (2). The vibrational spectra of 2 and its K+-complexes were obtained by restricted Hartree-Fock (RHF) calculations with the 6-31G basis set. The characteristic vibrational frequencies of various C-O-C stretching and bending motions are analyzed.

• Steel and Composite Structures
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• 제19권3호
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• pp.777-787
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• 2015

Production and properties of metal matrix composites reinforced with an in-situ high aspect ratio $AlB_2$ flake have been investigated. Boron 2.2wt.% was dissolved in pure Al and Al-Cu alloy at $1300^{\circ}C$ by adding directly boron oxide which resulted in 4 vol.% reinforcing phase. The in-situ $AlB_2$ flake concentration was increased up to 30 vol.% in order to increase the tensile strength of the composites. Hardness, compressive strength and tensile strength of the composite were measured and compared with their matrix. Results showed that 30 vol.% $AlB_2/Al$ composite show a 193% increase in the compressive strength and a 322% increase in compressive yield strength. Results also showed that ductility of composites decreases with adding $AlB_2$ reinforcements.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.62-67
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• 2002

While upwelling regions account for only 0.1% of the ocean surface, they yield over 40% of world's fish catch. Thus it is vary important making upwelling region by various methods. This study was performed to find out basic hydrodynamic characteristics (function, stability..,) of artificial upwelling structures. The hydrodynamic characteristics of artificial upwelling structures can be summarized as follows: 1) The falling velocity of blocks was effected size($l_B$) of blocks than incident current velocity( $V_0$). 2) The falling horizontal distance was reduced as induce of stratification parameters and block' size. 3) Generation of artificial upwelling current was effected by size of structures and incident current. When stratification parameters was about 3.0 and relative height(hs/h) of structures was about $0.125{\sim}0.15$, stable artificial upwelling current was generated in the back-side of structures.

• 한국안광학회지
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• 제7권1호
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• pp.57-61
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• 2002

3성분 $SrO-B_2O_3-SiO_2$ 유리들을 R(${\equiv}SrO\;mole%/B_2O_3\;mole%$)과 K(${\equiv}SiO_2\;mole%/B_2O_3\;mole%$)에 의하여 제작하여 유리들의 구조를 적외선 투과(Infrared transmittance), 경도(hardness) 그리고 굴절률(refractive index)을 이용하여 조사하였다. 첫째, 적외선 투과 스펙트럼에 의한 유리구조들의 변화는 R의 증가에 따라 $1200{\sim}1600cm^{-1}$ 영역에서 $BO_3$ 단위구조에 의한 B-O 결합의 신축떨기(stretching vibration)에 의한 흡수 띠의 세기가 감소되어지며, 사면체 구조인 $BO_4$ 단위구조에 의한 B-O 결합의 신축떨기에 의한 흡수 띠의 세기는 $800{\sim}1200cm^{-1}$ 영역에서 변화되어졌다. 그리고 K의 증가에 따라 $BO_3$ 단위구조에 의한 B-O 결합의 신축떨기에 의한 흡수 띠의 세기는 증가되어지며, 사면체 구조인 $BO_4$ 단위구조에 의한 B-O 결합의 신축떨기에 의한 흡수 띠의 세기가 감소하였다. 둘째, 유리들의 경도는 유리 망목구조(network) 내에 형성되어지는 $BO_4$와 $BO_3{^-}$ 단위구조들의 수에 의존하여 각각 증가와 감소하였으며, 굴절률은 SrO량에 크게 의존하였으며 유리 망목구조 내에 형성되어지는 $BO_4$와 $BO_3{^-}$ 단위구조 수에 적게 의존함을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제13권11호
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• pp.963-968
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• 2000

Magnetic properties and microstructures of Fe$\_$93-x/Zr$_3$B$_4$Ag$\_$x/ thin films were investigated as a function of addition of element Ag, (X$\_$Ag/=0 to 6 at.%) and annealing temperature, T$\_$a/=300$\^{C}$ to 600$\^{C}$. In the case of adding Ag, magnetic properties of Fe$\_$93-x/Zr$_3$B$_4$Ag$\_$x/ thin films were improved than those of Ag-free Fe$\_$93/Zr$_3$B$_4$thin films. The prominent soft magnetic properties with coercivity of 1.1 Oe, saturation magnetization of 2.2 T and permeability of 5400 at 50㎒ were obtained from Fe$\_$88/Zr$_3$B$_4$Ag$\_$5/ thin film annealed was lower than that of Fe-base or Co-base thin films reported previously. Such enhanced magnetic properties are presumably attributed to the format in ultra fine grains. Also, the reduced eddy current loss in the annealed sample is due to refined micro magnetic domains with increasing the amount of Ag in Fe$\_$93-x/Zr$_3$B$_4$Ag$\_$x/ thin films.

• 한국염색가공학회지
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• 제2권1호
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• pp.8-13
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• 1990

The fading of dyed material by light has long been subject of investigation, yet surprisingly little is known of the fundamental photochemical reactions, because of mainly the complex nature of dye-fibre system. The effect of the chemical structure of dye on lightfastness has been mostly studied when there is substituents on the place satisfied Hammett rule. Therefore, in this investigation the effectiveness of chemical structures of Congo Red and Benzopurpurine 4B unsatisfied Hammett rule on dyeing property and lightfastness of cotton was studied. The results obtained from this study were as follows; 1. Highly polar solvents showed hypsochromic shift. 2. Adsorption isotherm curves of the two dyes were Freundlich type. And Congo Red showed good dyeing property in comparision with Benzopurpurine 4B. 3. The type of the FR curve of the two dyes was first-ordr curve. And the CF curves of the two dyes showed normal fading state during irradiation. 4. During irradiation, the Hue was changed on the part of yellowish. The Value was increasing and the Chroma was decreasing. 5. Benzopurpurine 4B showed good lightfastness in comparision with Congo Red.

• Archives of Pharmacal Research
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• 제27권11호
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• pp.1081-1085
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• 2004

Several 2-[[(benzoxazole/benzimidazole-2-yl)sulfanyl]acetylamino]thiazoles derivatives were synthesized by reacting 4-substituted-2-(chloroacetylamino)thiazoles with benzoxazole/benzimidazole-2-thioles in acetone and in the presence of $K_2CO_3$. The chemical structures of the compounds were elucidated by IR, $^1H-NMR$, and $FAB^{+}-MS$ spectral data. Their antimicrobial activities against Micrococcus luteus (NRLL B-4375), Bacillus cereus (NRRL B-3711), Proteus vulgaris (NRRL B-123), Salmonella typhimurium (NRRL B-4420), Staphylococcus aureus (NRRL B-767), Escherichia coli (NRRL B-3704), Candida albicans and Candida globrata (isolates obtained from Osmangazi Uni. Fac.of Medicine) were investigated and in this investigation, a significant level of activity was illustrated.