• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1158-1161
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• 2004

Shell shaped hollow carbon nanoparticles are synthesized in the oxygen-hydrogen diffusion flame with $C_{2}H_{2}$ as precursor when it is irradiated with $CO_{2}$ laser of certain power. Below this power of laser, we couldn't get any other but amorphous soot. This shell shaped hollow carbon nanoparticles shows outer wall of high degree of crystallinity with void space inside of itself. And size distribution of these nanoparticles is measured with TEM image analysis. Also the structural comparison between this carbon nanoparticle and soot is done by Raman and XRD measurement. These results show this carbon nanoparticles are of grapheme structure, which means it has good crystallinity when compared with soot.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1331-1335
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• 2011

We report the results of the characterization of Cu oxide thin films deposited by radio frequency (r.f.) magnetron sputtering at different annealing temperatures. The deposited Cu oxide thin films were investigated by scanning electron microscopy, spectroscopic ellipsometry, X-ray diffraction, atomic force microscopy, Xray photoelectron spectroscopy, and contact angle measurements. The thickness of the films was about 180 nm and the monoclinic CuO phase was detected. The $CuO_2$ and $Cu(OH)_2$ phases were grown as amorphous phase and the ratio of the three phases were independent on the annealing temperature. The surface of Cu oxide films changed from hydrophilic to hydrophobic as the annealing temperature increased. This phenomenon is due to the increase of the surface roughness. The direct optical band gap was also obtained and laid in the range between 2.36 and 3.06 eV.

• Journal of Astronomy and Space Sciences
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• v.24 no.2
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• pp.111-118
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• 2007

We have studied energetic neutral atom (ENA) disturbances during the magnetic storm main phase that occurred on October 3,2001, using the ENA data from the HENA instrument onboard the IMAGE spacecraft. We find that the main phase is characterized by five ENA enhancement events that occurred quasi-periodically. The repetitive ENA enhancements are most significant in the highest energy (138-222 keV) oxygen channel and become less significant for hydrogen and in lower energies. Also they are separated by ${\sim}1.2$ to ${\sim}1.7$ hrs, which is well below an average period usually seen for other repetitive injection events.

• Journal of Ocean Engineering and Technology
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• v.20 no.5 s.72
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• pp.82-88
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• 2006

This assessment is concerned with the fatigue strength of the tendon porch found in TLP. Lorge-scale fatigue tests with models constructed at 30% the size of the real structures have been carried out to investigate the fatigue behavior of the API 2W Grade 50 steel recently produced by POSCO. The fatigue life for the present test models was obtained based on the concept of nominal stress. A comparison of the present test results with those obtained by a numerical approach based on the structural analysis results has showngood agreement. The present results were also compared with the design curves in DnV RP-C203.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.104-105
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• 2008

요즘 데이터의 양이 많아지고 마이크로프로세서의 속도가 빨라짐에 따라 광통신이 각광받고 있다. 광통신이란 전류신호를 광 신호로 변환하여 송신하고 광섬유를 통해 전달된 광신호가 포토다이오드를 통해 전류신호로 변환되어 수신하는 통신방법이다. TIA는 이런 광통신의 수신부의 첫 단에 오는 블록으로서 전류신호를 사용가능한 전압신호로 바꾸어주는 역할을 한다. 본 논문에서는 포토다이오드의 커패시턴스 성분을 효과적으로 차단하고 노이즈 특성을 향상시킬 수 있는 방법을 제안하고, 1.8V 0.18um CMOS공정을 사용하여 2.5Gbps TIA 블록을 설계하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1407-1410
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• 2007

This work reports on three primary color fluorescent white organic light emitting diode (WOLED) with simple device structure where only a part of the hole transporting layer was doped with dye. The maximum luminance of the device reaches $35000\;cd/m^2$ at a drive voltage below 11V and external quantum efficiency of the device is above 1% in the wide range of luminance from 10 to $35000\;cd/m^2$ and reaches its highest 1.6% at $500\;cd/m^2$. The chromaticity coordinate shift of the device is negligible in this wide range of luminance. The blue shift of emission color with an increase of current density was attributed to the narrowing of recombination zone width with raise of current density.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1144-1147
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• 2002

Ferroelectric $Sr_xBa_{1-x}Nb_2O_6(0.25{\leq}x{\leq}0.75)$ thin films were prepared by the Ion Beam Sputtering method. Deposit onto Pt/Ti/$SiO_2$/Si(100) substrates. The deposited thin films were heat-treated for crystallization. Microstructure and crystallization behavior were examined using FE-SEM, XRD. Ferroelectric hysteresis were measured. The measured remanent polarization and coercive field values were $38{\mu}C/cm^2$ and 120kV/cm, respectively.

• Macromolecular Research
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• v.13 no.2
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• pp.128-134
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• 2005

The phosphorus comonomer [(6-oxido-6H-dibenz<1,2>oxaphosphorin-6-yl)methyl]-methyl butane-dioate (DOP-MBDA) was synthesized through the addition reaction of dimethyl itaconate (DMI) with 9,10-dihydro­9-oxa-10-phosphaphenan threne-10-oxide (DOP). A series of novel flame retardant poly(butylene terephthalate)s (PBTs) containing different amounts of phosphorus were prepared using DOP-MBDA as a comonomer. These novel polymers were characterized by $^{1}H-NMR$, IR, and differential scanning calorimetry (DSC). The novel phosphorus­containing poly(butylene terephthalate)s, referred to as FR-PBTs, exhibited interesting thermal and mechanical behavior, as well as superior flame retardancy. These properties are attributed to the effect of incorporating the rigid structure of DOP-MBDA and the pendant phosphorus group into the poly(butylene terephthalate) (PBT) homopolymer. The UL 94-V2 rating could be achieved with this novel flame retardant PBT, which has a phosphorus content as low as $0.5 wt\%$, and the FR-PBTs emitted less fumes and toxic gases than the PBT homopolymer.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.158-161
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• 2003

Toxicity evaluations of 3-tert-butyl-, 2-isopropyl-, 3-isopropyl- and 4-propyl-phenol and their binary mixtures were performed with the Microtox$\^$(R) / assay and compared to invertebrates and fish. The single chemical, 4-isopropylphenol, exhibited the greatest relative toxicity to the Microtox organism (Vibrio fischeri). The relative electrophilicity (LUMO) of the phenols, in contrast to the lipophilicity (Log P), was strongly correlated with toxicity to V fischeri (r$^2$=0.96, p<0.01). In contrast, relative electrophilicity alone could not explain variances in toxicity of the phenols to Ceriodaphnia dubia. Results suggest that electrophilicity in conjunction with lipophilicity provide better correlation with toxicity to C. dubia and Pimephales promelas. Microtox results from the binary mixture toxicity tests of selected phenolics indicate a mechanism of interaction governed by suppression/antagonism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.2
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• pp.175-179
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• 1990

Investigations of skin stripping freezing and thawing conditions of common-European squid (Loigo vulgaris) were carried out. The most effective method of skin stripping was to immerse the sample at 5$0^{\circ}C$ for 10-15 minutes in fresh water or salt solution(5-10% w/v) Contact freezing and fresh water thawing method was found to be effective. The muscle structure of the sample thawed after contact freezing was almost the sample after contact freezing was almost the same as that of raw sample.