• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2012.10a
• /
• pp.332-334
• /
• 2012

This study investigates records about state systems which were installed to manage aids to navigation workings related to ship and navigation in Korea. It shows the transition process from signal-fire that was used for safe sailing in the three kingdom period to the oil lamp, acetylene gas light, electric light and the LED lamp have been used as a light source for the lighthouses since the modern age.

• Journal of the Korean Vacuum Society
• /
• v.7 no.2
• /
• pp.127-134
• /
• 1998

Stainless steel is being used widely for various purposes due to its good corrosion resistance. There has been much research to produce a colored and corrosion-resistant stainless steel by several methods to use in decorating. In this experiment, we coated TiN(C,O,H)films on the SUS304 substrates with the DC magnetron sputtering system and then studied the texture and color of the films as a function of additional gases being inserted into the system. A (220) texture of TixN film changed to (200) by the addition of either hydrogen or the acetylene and changed further to (111) with an increase of the additional acetylene content. The addition of oxygen gas changed from the texture(220) to (111) to (200). The color of the TixN film changed from gold to gray to green with the increase of the content by the addition of oxygen gas, while it changed to pink and finally to gray with the increased of the content by the addition of acetylene gas. Reflectance increased in the region of short wavelength by the addition of hydrogen, but decreased with the increase of the oxygen and the acetylene content.

• Journal of the Korean Society for Heat Treatment
• /
• v.11 no.4
• /
• pp.342-346
• /
• 1998

• Korean Journal of Optics and Photonics
• /
• v.8 no.1
• /
• pp.68-72
• /
• 1997

Using one of the absorption lines of $^{13}C_2H_2$ molecules near the zero dispersion wavelength(1549.49nm) of dispersion shifted fiber, we stabilized center frequency of an optical fiber Fabry-Perot filter. The free spectral range of the filter is 100 GHz for 100 GHz channel allocation. For equi-spaced three channel multiplexing, channel locking of three DFB-LDs to transmission peaks of the fiber Fabry-Perot filter was tried. To investigate the effect of dithering current applied to each DFB-LD, the change of DFB-LD linewidth was measured.

• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.4
• /
• pp.353-357
• /
• 1983

A field study was conducted for 20 soil columns to investigate the denitrification in the grassland with a method introducing $C_2H_2$ in the denitrifying system. Since acetylene blocked the pathway from $N_2O$ to $N_2$, all the free products of denitrification consisted of nitrous oxide. In this study, denitrification was measured as $N_2O$. Results are as follows. 1. In most of boils examined, denitrification was observed as $N_2O$ when acetylene was introduced into the denitrification system while $N_2O$ was scarcely evolved without acetylene in the system. 2. Denitrification occurred even in the grassland soils when they were saturated with water. Denitrification was nil or negligible without water saturation. 3. Denitrification loss far 3 days incubation(from 13th to 16th day after urea application) was 4.2% in average and 14.2% in maximum. 4. Soil chemical properties such as nitrate nitrogen, nitrite nitrogen, total nitrogen, total carbon and mineralizable carbon did not show clear relationships with denitrificatien, probably since soil chemical properties were analysed for the soils after incubation.