• Korean Journal of Materials Research
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• v.8 no.6
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• pp.477-483
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• 1998

$SiC_{4}$$C_{3}$$H_{ 8}$$H_{2}$와 $C_{3}$$H_{8}$ $H_{2}$, $CH_{3}$$SiCI_{3}$$CH_{4}$$H_{2}$계를 사용하여 흑연기판 위에 SiC와 SiC/C FGM을 CVD법에 의해 코팅하였다. $SiCI_{4}$$C_{3}$$H_{8}$ $H_{2}$ 계에서 SiC 증착 시 바람직한 수소의 비는 10-30사이였고 결정 배향성은 입력가스의 탄소비에 따라 여러번의 대 반전이 일어났다. 성장조건을 {111} 배향성을 갖도록 조절하는 것이 FGM층간 접착상태를 증진시킬 수 있는 방법으로 판단되었다. $CH_{3}$$SiCI_{3}$C$_{3}$$H_{8}$ $H_{2}$ 계에서는 SiC와 C의 비율을 조절하기가 $SiCI_{4}$$C_{3}$$H_{8} $H_{2}$계를 사용했을 때 보다 용이하였고, FGM 단면 관찰에서 층간의 뚜렷한 경계를 발견할 수 없을 정도로 우수한 층간 접착상태를 보였다.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.168-170
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• 2002

Magnetization studies were conducted on a single crystal of $YNi_{2}$$B_{2}$C superconductor. The 17 mg crystal was studied at temperatures T from above $T_{c}$ (15.5 K) to 3 K, in the magnetic fields H // c-axis up to 6 tesla. The crystal exhibited little magnetic irreversibility, with a critical current density $CO_{3}$ ~ $10^{-4}$ $\times$ $CO_{3}$, the depairing current density. Near $T_{c}$, the equilibrium magnetization M was London-like with M $\infty$ In(H). The upper critical field $H_{c2}$ of the single crystal $YNi_{2}$$B_{2}$C was estimated by the several alternative approaches such as standard London limit, Ginzburg-Landau, and Abrikosov relations. The estimated $H_{c2}$values agree relatively well with each other approaches.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.147-151
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• 2010

In this study, the clay specimen of Busan-Gyeongnam region was used for unconfined compression test to compare the relationship formula between elasticity modulus at peak($E_f$), elasticity modulus at $q_u$/2($E_{50}$), and cohesion when the sample breaks down by region and by level of cohesion. As the result, the regional results were found to be in the range of $E_f$ = 14c~47c and $E_{50}$ = 43c~137c; by cohesion, the results for very soft ground was $E_f$ = 15c~40c and $E_{50}$ = 54c~101c, $E_f$ = 13c~63c and $E_{50$ = 40c~147c for soft ground, $E_f$ = 18c~47c and $E_{50}$ = 57c~144c for medium ground, and $E_f$ = 25c~45c and $E_{50}$ = 68c~115c for solid ground. The average of the relationship formula between elasticity modulus-cohesion for the clay used in this study was $E_f$ = 32c, $E_{50}$ = 93c. This is 2.5~5 times smaller than the existing relationship formula.

• BMB Reports
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• v.30 no.6
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• pp.397-402
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• 1997

A thiol-specific spin label was attached to cysteine-102 of yeast cytochrome c and electron paramagnetic resonance (EPR) spectra were measured as a function of added cytochrome c oxidase concentration. The intensity decreased due to line broadening as cytochrome c formed a complex with cytochrome c oxidase and reached a minimum when the ratio of cytochrome c to cytochrome c oxidase became one. Replacement of either Lys-72 or Lys-87 of cytochrome c by Glu did not result in a significant change in binding affinity. Interestingly the K72E mutant, unlike K87E, had a much lower rate of electron transfer than the wild type. These results indicate that many positively charged residues as a group participate in complex formation but Lys-72 might be important for cytochrome c to be locked in an orientation for an efficient electron transfer. A stoichiometry of 1 was also confirmed by optical absorption of the cytochrome c-cytochrome c oxidase complex which had been run through a gel chromatography cloumn to remove unbound cytochrome c. The EPR spectrum of this 1:1 complex, however, was a mixture of two components. This explains a biphasic kinetics for a single binding site on cytochrome c oxidase without invoking conformational transition.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.578-582
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• 2010

$ZrB_2$ has a melting point of $3245^{\circ}C$ and a relatively low density of $6.1\;g/cm^3$, which makes this a candidate for application to ultrahigh temperature environments over $2000^{\circ}C$. Beside these properties, $ZrB_2$ is known to have excellent resistance to thermal shock and oxidation compared with other non-oxide engineering ceramics. In order to enhance such oxidation resistance, SiC was frequently added to $ZrB_2$-based systems. Due to nonsinterability of $ZrB_2$-based ceramics, research on the sintering aids such as $B_4C$ or $MoSi_2$ becomes popular recently. In this study, densification and high-temperature properties of $ZrB_2$-SiC ceramics especially with $B_4C$ are investigated. $ZrB_2$-20 vol% SiC system was selected as a basic composition and $B_4C$ or C was added to this system in some extents. Mixed powders were sintered using hot pressing (HP). With sintered bodies, densification behavior and high-temperature (up to $1400^{\circ}C$) properties such as flexural strength, hardness, and so on were examined.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.265-266
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• 2007

본 논문에서는 안전등급 PLC(Programable Logic Controller) LD/FBD(Ladder/Function Block Diagram) 프로그램을 C-코드로 변환하는 C-코드 발생기의 시험에 관해서 다룬다. 개발된 C-코드 발생기는 로직 분석, 오류 검출, C-코드 생성 등 각 부분 별로 시험 항목을 설정하고 검증하는 방법에 대해서 서술한다. 또한 C-언어로 작성된 사용자 정의 함수/함수 블록에 관한 시험 항목을 기술한다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.355-356
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• 2006

WC-TiC-TaC binderless cemented carbide was oxidized under low partial pressure of oxygen (50ppm) at 873K for 1 to 20 h. Surface roughness was measured using atomic force microscope, and effect of TiC amount on oxidation behavior of the carbide was investigated. WC phase was oxidized more easily than WC-TiC-TaC solid solution phase. With an increase in TiC amount, WC-TiC-TaC phase increased and the oxidation resistance of the carbide increased.

• Journal of the Korean Mathematical Society
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• v.32 no.4
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• pp.835-848
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• 1995

Let $M_n$(c) be an n-dimensional complete and simply connected Kahlerian manifold of constant holomorphic sectional curvature c, which is called a complex space form. Then according to c > 0, c = 0 or c < 0 it is a complex projective space $P_nC$, a complex Euclidean space $C^n$ or a complex hyperbolic space $H_nC$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.217-217
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• 2009

This paper describes the characteristics of polycrystalline 3C-SiC doubly clamped beam micro resonators. The polycrystalline 3C-SiC doubly clamped beam resonators with 60 ~ 100 ${\mu}m$ lengths, $10\;{\mu}m$ width, and $0.4\;{\mu}m$ thickness were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonant frequency was measured by a laser vibrometer in vacuum at room temperature. For the 60 ~ 100 ${\mu}m$ long cantilevers, the fundamental frequency appeared at 373.4 ~ 908.1 kHz. The resonant frequencies of doubly clamped beam with lengths were higher than simulated results because of tensile stress. Therefore, polycrystalline 3C-SiC doubly clamped beam micro resonators are suitable for RF MEMS devices and bio/chemical sensor applications.

• Polymer(Korea)
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• v.38 no.4
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• pp.425-433
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• 2014

In this study, microstructure and gel content (C-C) of polybutadiene rubber (PBR) were investigated using various techniques including ASTM D 3616, attenuated total reflectance Fourier transform infrared spectrometry (ATR FTIR), differential scanning calorimetry (DSC) and nuclear magnetic resonance spectroscopy (NMR). The ATR FTIR spectra of the samples were investigated to determine the cis, trans, 1, 2-vinyl and the C-C gel content in PBR. The absorbance ratios of specific peaks in different grades of PBR were correlated with the C-C gel content measured by the ATR FTIR techniques. Physico-mechanical and rheological properties of rubber compounds based on BR with various amounts of gel were determined. The results showed that there is an acceptable correlation between these properties and the C-C gel content of PBR.