• Bulletin of the Korean Space Science Society
• /
• 2003.05b
• /
• pp.18-18
• /
• 2003

No Abstract, See Full Text

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2002.02a
• /
• pp.13-16
• /
• 2002

Ru thin films were deposited on bi-axially textured Ni tape using rf-magnetron sputtering for a conductive buffer layer of high Tc superconductor applications. (002) textured Ni films were fabricated as the deposition temperature was over $600^{\circ}C$. Rocking curves of the films showed similar alignment to those the Ni tapes. The resistivity of the tapes fabricated below $600^{\circ}C$ was around 20$\mu\Omega$-cm which is good for the conductive layer for tape superconductor applications.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.8
• /
• pp.1791-1796
• /
• 2011

An optical fiber short period grating of 0.7 nm as a 3 dB wavelength linewidth was fabricated using a Gaussian distributed KrF Eximer laser and a phase mask. This grating has temperature dependancy of 0.01 nm/$^{\circ}C$ over the range of -10 $^{\circ}C$ ~ 70 $^{\circ}C$and no difference between temperature directions. An optical fiber long period grating of 14.22 nm as a 3 dB linewidth was also fabricated using a amplitude mask and has dependancy of 0.01 nm/$^{\circ}C$ over the same range.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.6
• /
• pp.1-6
• /
• 2010

Patterned optical components are widely used for optical products such as LCD and lighting. Since CCFL was used as a light source in the products, prism films having linear continuous optical patterns were widely used. However, LED which is a dot light source is popular recently, therefore, the optical products need new optical components having non-continuous optical patterns. Indentation machining method is a powerful method for machining of non-continuous pattern. When a copper mold and a brass mold were machined by this method, severe plastic deformation called pile-up was observed around the patterns. Since pile-up has negative relationship to ductility, this deformation can be eliminated by annealing treatment which makes the materials ductile. No plastic deformation occurred when machined after annealing at $600{^{\circ}C}$ and $575{^{\circ}C}$ for copper and brass, respectively. Finally, non-continuous optical patterns with high quality were machined on a copper mold and a brass mold successively.

• Korean Journal of Materials Research
• /
• v.16 no.9
• /
• pp.578-583
• /
• 2006

We studied the physical properties of Ni-Zn ferrites by adding different chemicals such as $SO_4$, Cl, and $NO_3$. Specimens were prepared by the coprecipitation method and sintered at temperatures $950^{\circ}C,\;1,150^{\circ}C,\;and\;1,350^{\circ}C$, respectively. X-ray diffractions showed a spinel structure and the optical microscopy revealed grain size of 0.3 to 0.6 ${\mu}m$. The optimum sintering temperature to obtain fine, sintered microstructure depended on the additive : Cl and $NO_3\;at\;950^{\circ}C\;and\;SO_4\;at\;1,150^{\circ}C$. According to particle size analysis, higher magnetic permeability and magnetization value were observed with Cl and $NO_3\;than\;SO_4$. As sintering temperature was raised from $950^{\circ}C$ to $1,350^{\circ}C$, the average grain diameter, initial permeability and the magnetic moment also increased.

• Journal of the Korean Society of Combustion
• /
• v.11 no.3
• /
• pp.18-25
• /
• 2006

The present studying is aimed to establish the relationship between flame chemiluminescence$(OH^*,\;CH^*,\;C_2^*)$ intensities and combustion conditions such as $NO_x$ emission characteristics. Measurements are made for $OH^*,\;CH^*,\;C_2^*$ radicals in gas & light oil diffusion flames. At turbulent nonpremixed combustion mode, the equivalence ratio is varied. The optical emissions were measured by photomultiplier(PMT) using optical band pass filter and spectrometer system. The experimental results showed that the ratio of radicals and $NO_x$ emission characteristics have exponential correlations and equivalence ratio characteristics have linear correlations at this experimental conditions.

• Korean Journal of Materials Research
• /
• v.12 no.5
• /
• pp.414-422
• /
• 2002

Three different multi-component white cast irons alloyed with Cr, V, Mo and W were prepared in order to study their as-cast and solidification structures. Three combinations of the alloying elements were selected so as to obtain the different types of carbides and matrix structures : 3%C-10%Cr-5%Mo-5%W(alloy No.1), 3%C-10%V-5% Mo-5%W(alloy No. 2) and 3%C-17%Cr-3% V(alloy No.3). The as-cast microstructures were investigated with optical and scanning electron microscopes. There existed two different types of carbides, $M_7C_3$ carbide with rod-like morphology and $M_6C$ carbide with fishbone-like one, and matrix in the alloy No. 1. The alloy No. 2 consisted of MC carbide with chunky and flaky type and needle-like $M_2C$ carbide, and matrix. The chunky type referred to primary MC carbide and the flaky one to eutectic MC carbide. The morphology of the alloy No. 3 represented a typical hypo-eutectic high chromium white cast iron composed of rod-like $M_7C_3$ carbide which is very sensitive to heat flow direction and matrix. To clarify the solidification sequence, each iron(50g) was remelted at 1723K in an alumina crucible using a silicon carbide resistance furnace under argon atmosphere. The molten iron was cooled at the rate of 10K/min and quenched into water at several temperatures during thermal analysis. The solidification structures of the specimen were found to consist of austenite dendrite(${\gamma}$), $ ({\gamma}+ M_7C_3)$ eutectic and $({\gamma}+ M_6C)$ eutectic in the alloy No. 1, proeutectic MC, austenite dendrite(${\gamma}$), (${\gamma}$+MC) eutectic and $({\gamma}+ M_2C)$ eutectic in the alloy No. 2, and proeutectic $M_7C_3$ and $ ({\gamma}+ M_7C_3)$ eutectic in the alloy No 3. respectively.

• The KIPS Transactions:PartC
• /
• v.13C no.4 s.107
• /
• pp.441-446
• /
• 2006

In recent years, WDM networks have received much attention as the Internet backbone networks because of the explosive growth of the Internet IP-based traffic. The Optical Burst Switching (OBS) has been proposed as an effective optical switching technology in the WDM networks. The OBS has the advantages in 1) the high usage rate of the bandwidth, and 2) no necessity of optical buffer. However, the OBS has the burst-contention problem in the networks. The deflection routing is proposed as one of means to solve this problem. In this paper, we propose a new routing method to minimize burst loss in the deflection routing based networks. In addition, we propose a QoS control method using a new routing algorithm. Finally, we show the variety of the proposed methods by computer simulations.

• Journal of Korean Ophthalmic Optics Society
• /
• v.4 no.2
• /
• pp.57-63
• /
• 1999

The optical absorption and transmittance of cow' crystalline were measured by spectrophotometer in the 200~800nm wavelength regions. The optical absorptions of crystalline composed of a high absorption band in the UV-A, UV-B, and appeared the light transmittance edge in the 400nm wavelength region, and completely transmitted without the absorption in the high wavelength regions than 400nm. Also, the optical absorption and transmittance had no temperature dependence. The optical transmittance spectrum of crystalline concord with the thin film structure of $n_0/(0.5H)L(LH)^6(0.5H)/n_s$ and $n_0{\mid}(0.5LH0.5L)^kL/1.25{\mid}4.0$ of long-pass edge filter form. In the artificial crystalline and inter lens layout, long-pass edge filter layout can UV cut off.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.2
• /
• pp.424-430
• /
• 2011

A novel T-type polyurethane 7 containing 1-(2,5-dioxyphenyl)-2-(5-(1,2,2-tricyanovinyl)-2-thienyl)ethenes as NLO chromophores, which constitute part of the polymer backbone, was prepared. Polyurethane 7 is soluble in common organic solvents such as DMF and DMSO. It shows a thermal stability up to $270^{\circ}C$ from TGA thermogram with $T_g$ value obtained from DSC thermogram near $155^{\circ}C$. The second harmonic generation (SHG) coefficient ($d_{33}$) of poled polymer film at 1560 nm fundamental wavelength is $3.56{\times}10^{-9}$ esu. Polymer 7 exhibits a thermal stability even at $5^{\circ}C$ higher than $T_g$, and no significant SHG decay is observed below $160^{\circ}C$, which is acceptable for nonlinear optical device applications.