• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.372-372
• /
• 2007

Titanium oxide nanotube arrays were fabricated by the anodization of pure titanium thin film deposited at $500^{\circ}C$ on silicon substrates. The titania nanotubes were grown by anodization in nonaqueous-base electrolytes at different potentials between 5 V and 30 V. $TiO_2$ nanotube array with a small pore diameter of 40 nm and long titanium oxide layer of $4\;{\mu}m$ was obtained. The $TiO_2$ nanotube array was used as a porous electrode for quartz crystal microbalance (QCM). Nanoporous morphology of electrode will increase the sensitivity of microbalance.

• Macromolecular Research
• /
• v.16 no.4
• /
• pp.353-359
• /
• 2008

Spheres of silicon resins with different compositions were prepared in one-step reaction from mixtures of water and water-insoluble precursors of polysiloxanes (PSO) and polysilsesquioxanes (PSQ) using different amines as catalysts. The presence of PSO and PSQ in the spheres was confirmed by their mechanical properties and FTIR spectroscopy. Spheres of pure PSO were obtained from only dimethoxymethylvinylsiloxane (DMMVS) and 3-mercaptopropylmethyldimethoxysilan (MPMDMS) when the reaction was induced with appropriate catalysts. DMMVS and MPMDMS always gave the most promising results regarding the formation of discrete solid spheres with the minimum tendency to form monolithic solids or fluid-like, premature products. The spheres were characterized by optical microscopy, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The mixtures containing larger amounts of PSO precursors commonly gave lower yields and softer spheres.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.130-133
• /
• 2005

Efficient finite element method has been introduced for metallic sandwich plates subject to 3-point bending. A full model 3-point bending FE-analysis shows that plastic behavior of inner structures appears only at the load point. So, Unit structures of sandwich plates are defined to numerically calculate the bending stiffness with recurrent boundary condition of pure bending. And then equivalent models with same bending stiffness and strength of full models are designed analytically. It is demonstrated that results of both models are almost same and FE analysis method with equivalent models can reduce analysis time effectively.

• The Pure and Applied Mathematics
• /
• v.15 no.4
• /
• pp.407-414
• /
• 2008

In this paper, we study the self-adjoint second order boundary value problem with integral boundary conditions: (p(t)x'(t))'+f(t,x(t))=0, t $${\in}$$ (0,1), x'(0)=0, x(1) = $${\int}_0^1$$ x(s)g(s)ds. A new result on the existence of positive solutions is obtained. The interesting points are: the first, we employ a new tool-the recent Leggett-Williams norm-type theorem for coincidences; the second, the boundary value problem is involved in integral condition; the third, the solutions obtained are positive.

• The Pure and Applied Mathematics
• /
• v.17 no.1
• /
• pp.39-49
• /
• 2010

This paper deals with the second-order differential equation (p(t)x'(t))' + g(t)f(t, x(t), x'(t)) = 0, a.e. in (0, $\infty$) with the boundary conditions $$x(0)={\int}^{\infty}_0g(s)x(s)ds,\;{lim}\limits_{t{\rightarrow}{\infty}}p(t)x'(t)=0,$$ where $g\;{\in}\;L^1[0,{\infty})$ with g(t) > 0 on [0, $\infty$) and ${\int}^{\infty}_0g(s)ds\;=\;1$, f is a g-Carath$\acute{e}$odory function. By applying the coincidence degree theory, the existence of at least one solution is obtained.

• The Pure and Applied Mathematics
• /
• v.16 no.2
• /
• pp.213-225
• /
• 2009

This paper deals with the existence of positive solutions for a kind of multi-point nonlinear fractional differential boundary value problem at resonance. Our main approach is different from the ones existed and our main ingredient is the Leggett-Williams norm-type theorem for coincidences due to O'Regan and Zima. The most interesting point is the acquisition of positive solutions for fractional differential boundary value problem at resonance. And an example is constructed to show that our result here is valid.

• Journal of Plant Biology
• /
• v.27 no.2
• /
• pp.95-103
• /
• 1984

The Populus maximowiczii dominated forest of the Sangcheon ravine, Mt. Seolag, is distributed in the area with the conglemerates substrate, along the ravine stream from 170m to 550m in altitude. Toward the both slopes of the northern and southern peak from the stream side, the zonal distribution of vegetation was recognized; P. maximowiczii forest of Pinus densiflora forest and deciduous broad leaved forest. The pure community of P. maximowiczii with even more 80-98% in relative basal area (aspen basal area/basal area) was found in the ravine area from 360m to 420m in altitude, the optimal ranges in the species and community by two dimensional ordination with thermal and xeric cline axis. The species compete with Pinus densiflora, in the ravine stream side, and with deciduous broad leaved tree species such as Fraxinus rhynchophylla, Prunus sargentii, Lindera obtusiloba, in the mountain slope sides. On the other hand, the ravine vegetation, including the aspen forest, was classified into Pinus densiflora, Pinus densiflora-Carpinus laxiflora, Pinus densiflora-Populus maximowiczii, jessoensis, Acer mono-Fraxinus rhynchophylla, Carpinus laxiflora-Quercus mongolica, Quercus variabilis-Quercus ariena, Quercus ariena, Quercus variabilis-Stephanandra incisa, Picrasma quassioides-Celtis sinensis, Betula davurica-Zanthoxylum schinifolium and Styrax obassia-Lindera obtusiloba association.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.173-175
• /
• 2003

At the low temperature of $950^{\circ}C$ the $\mu\textrm{m}$-sized whisker growth during the catalytic CVD of pyrolytic carbon from methane with $H_2$- and Ar-gas on quartz substrate with NiO powder was found in this work. In the preliminary study it was observed from pure methane pyrolysis without catalyst at the high temperature $1500~1700^{\circ}C$. If the growth whisker should be stopped at initial stage, about 20 min. of the methane pyrolysis, it would be nanosized whisker growth. The screw growth mechanism and unique mechanical properties of whisker for composites were also recognized. If the pyrolysis would be continued, we could found also spiral growth of whistlers with diameter of about 1, 5 mm. The large length of whisker was about 10 cm in 20 minute.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2008.11a
• /
• pp.1258-1261
• /
• 2008

본 논문은 시스템의 안정성과 검증성, 설계 및 관리 용이성을 위해 SDL 언어 및 Pure-SDL 설계 접근기법을 이용하여 3GPP LTE 액세스 시스템 검증을 위한 단말 시뮬레이터를 설계 및 구현하였다. 설계된 시스템은 관리 효율성을 위해 블록 타입 및 공통 패키지 설계를 통한 다중 시스템 구조를 갖는다. 구현된 단말 시뮬레이터는 실제 3GPP LTE 액세스 시스템 검증에서 우수한 안정성을 보여주었다.

• Biomolecules & Therapeutics
• /
• v.18 no.2
• /
• pp.184-190
• /
• 2010

Clinical cases of pure red cell aplasia (PRCA) have been reported during the recombinant human erythropoietin (EPO) therapy for the anemia patients. PRCA is a rare hematological disorder leading to a severe anemia due to an almost complete stop of red blood cell production. Antibody (Ab)-associated PRCA is caused by the EPO-neutralizing Abs that eliminate the biological activity of EPO. In order to detect anti-EPO Abs in human sera, we performed conventional ELISA, directly coated bridging ELISA, and streptavidin coated bridging ELISA, and compared their sensitivity and specificity. Some false positive results were obtained in the conventional ELISA. One positive sample was detected successfully by streptavidin coated bridging ELISA, which was not appeared in the directly coated bridging ELISA. In conclusion, streptavidin coated bridging ELISA was substantially sensitive and specific format and one out of sixty-eight serum samples was proved to be anti-EPO positive.