• Fire Science and Engineering
• /
• v.25 no.6
• /
• pp.184-189
• /
• 2011

This study measured the AITs of n-butanol + n-decane system from ignition delay time (time lag) by using ASTM E659 apparatus. The AITs of n-butanol and n-decane which constituted binary system were $340^{\circ}C$ and $212^{\circ}C$, respectively. The experimental AITs of n-butanol + n-decane system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D. (average absolute deviation).

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.641-644
• /
• 1995

We have studied the effect of the nitrogen on the microstructure, thermomagnetic properties and corrosion resistance of Fe-Hf-C-N nanocrystalline thin films with high permeability and high saturation magnetization. These films were fabricated by reactive sputtering in $Ar+N_{2}$ plasma using an rf magnetron sputtering apparatus. As $P_{N2}$ increases, the microstructure changes from amorphous to crystalline $\alpha$-Fe phase and again returns to amorphous one. Spin wave stiffness constant increases with $P_{N2}$ until 5% $P_{N2}$, and then decreases with the further increase. This trend corresponds well with that of the microstructure with increasing $P_{N2}$. The Fe-Hf-C-N films with over 3% $P_{N2}$ show higher corrosion resistance than the N-free Fe-Hf-C films. The Fe-Hf-C-N films are considered to have high potentials for the head core materials suitable for high density recording systems, owing to their excellent soft magnetic properties and corrosion resistance.

• Korean Journal of Materials Research
• /
• v.18 no.10
• /
• pp.535-541
• /
• 2008

Growth behavior of InGaN/GaN self-assembled quantum dots (QDs) was investigated with respect to different growth parameters in low pressure metalorganic chemical vapor deposition. Locally formed examples of three dimensional InGaN islands were confirmed from the surface observation image with increasing indium source ratio and growth time. The InGaN/GaN QDs were formed in Stranski-Krastanow (SK) growth mode by the continuous supply of metalorganic (MO) sources, whereas they were formed in the Volmer-Weber (V-W) growth mode by the periodic interruption of the MO sources. High density InGaN QDs with $1{\sim}2nm$ height and $40{\sim}50nm$ diameter were formed by the S-K growth mode. Dome shape InGaN dots with $200{\sim}400nm$ diameter were formed by the V-W growth mode. InN content in InGaN QDs was estimated to be reduced with the increase of growth temperature. A strong peak between 420-460 nm (2.96-2.70 eV) was observed for the InGaN QDs grown by S-K growth mode in photoluminescence spectrum together with the GaN buffer layer peak at 362.2 nm (3.41 eV).

• Journal of agriculture & life science
• /
• v.46 no.3
• /
• pp.79-85
• /
• 2012

This study was conducted to examine the effect of dietary n-3/n-6 fatty acid (FA) ratio on in vitro dry matter digestibility (IVDMD), fermentation indices and FA profile. Rice bran was mixed with oil sources (cotton seed oil and linseed oil) to make the diets at 0.02, 0.29 and 0.61 of dietary n-3/n-6 FA ratio. These diets (0.5g) were placed into the incubation bottles with 40 ml of anaerobic culture medium, which contained rumen fluid and Van Soest medium at 1:2 ratio. Five replicates of each diet and two blanks were incubated at $39^{\circ}C$ for 48 hours. After incubation, the incubated contents were centrifuged. The residues were freeze-dried for DMD and FA analyses. The supernatant was used for pH, $NH_3-N$ and volatile fatty acid analyses. The concentrations of lactate (p<0.001) and iso-valerate (p<0.001) decreased linearly with increasing dietary n-3/n-6 FA ratio, but acetate concentration (p=0.056) and the ratio of acetate to propionate (p=0.005) was increased linearly. The concentrations of n-3, n-6 FA and the ratio of n-3/n-6 FA in residues increased (p<0.001) linearly with increasing dietary n-3/n-6 FA ratio, but C18:1n-9 FA concentration was decreased (p<0.001) linearly. With these results, it could affect fermentation characteristics and FA profile of rumen content by dietary n-3/n-6 FA ratio.

• Journal of the Korean institute of surface engineering
• /
• v.33 no.2
• /
• pp.93-100
• /
• 2000

Effects of Ti content and Ti underlayer on the pitting behavior of TiN coated AISI 304 stainless steel have been studied. The stainless steel containing 0.1~1.0wt% Ti were melted with a vacuum melting furnace and heat treated at $1050^{\circ}C$ for 1hr for solutionization. The specimen were coated with l$\mu\textrm{m}$ and 2$\mu\textrm{m}$ thickness of Ti and TiN by E-beam PVD method. The microstructure and phase analysis were conducted by using XRD, XPS and SEM with these specimen. XRD patterns shows that in TiN single-layer only the TiN (111) Peak is major and the other peaks are very weak, but in Ti/TiN double-layer TiN (220) and TiN (200) peaks are developed. It is observed that the surface of coating is covered with titanium oxide (TiO$_2$) and titanium oxynitride ($TiO_2$N) as well as TiN. Corrosion potential on the anodic polarization curve measured in HCl solution increase in proportion to the Ti content of substrate and by a presence of the Ti underlayer, whereas corrosion and passivation current densities are not affected by either of them. The number and size of pits decrease with increasing Ti content and a presence of the coated Ti film as underlayer in the TiN coated stainless steel.

• The Korean Journal of Ceramics
• /
• v.1 no.2
• /
• pp.101-105
• /
• 1995

Electrical discharge machinable $Si_3N_4$ was fabricated with the addtion of 20-60 vol% TiN by gas pressure sintering. Their sinterability, microstructure, mechanical and electrical properties were characterized as a function of the TiN content. The addition of TiN up to 20 vol% increased the flexural strength and fracture toughness as compared with those of the monolithic Si3N4. For the TiN content higher than 40 vol%, the electrical resistivity was lower than $1062\Omega$.cm. The $Si_3N_4$ with the addition of 40 vol% of TiN appears to have the optimum considerable sinterability, mechanical and electrical properties, and machinability. A microstructural analysis showed that the enhanced toughening was due to the crack deflection.

• Journal of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.142-150
• /
• 1991

The complexation of hydrazide schiff base ligands such as N,N'-oxalylbis(salicylaldehyde hydrazone), N,N'-malonylbis(salicylaldehyde hydrazone), and N,N'-succinylbis(salicylaldehyde hydrazone) with Cd(II) ion was studied by polarographic method in DMSO solution. The order of stability constants was OBSH < MBSH < SBSH, and these ligands formed stable complexes with Cd(II) ion. The stability constants of complexation were measured at various temperatures. As the results, ${\Delta}$H and ${\Delta}$S of the complexation were distributed on the complex stabilities.

• Animal Systematics, Evolution and Diversity
• /
• v.30 no.3
• /
• pp.196-205
• /
• 2014

This paper describes six new species of sponges in the genus Agelas from Kosrae Island, The Federated States of Micronesia. Most Agelasid sponges are known from only tropical regions. All the new Agelas species; A. fragum n. sp., A. kosrae n. sp., A. purpurea n. sp., A. bakusi n. sp., A. vansoesti n. sp. and A. incrustans n. sp. are compared with other valid species that were studied. Six new species differ from the other species by morphology, growth form, skeletal fibres, habitats and spicule size. Agelas fragum n. sp. is characterized by its tuberculate surface and primary fibres with brush-like spicules. Agelas kosrae n. sp. is differs in skeletal structure and have tertiary fibres. Agelas purpurea n. sp. is characterized by primary, secondary and tertiary fibres are all cored with spicules. Agelas bakusi n. sp. is similar to Agelas clathrodes in shape, but differs in the primary fibres. Agelas vansoesti n. sp. is characterized by having acanthostrongyles. Agelas incrustans n. sp. is distinguished by its encrusting and not cavernous interior.

• Journal of the Semiconductor & Display Technology
• /
• v.3 no.2
• /
• pp.17-21
• /
• 2004

Aluminum nitride(AlN) thin films were deposited on silicon substrate by reactive RF magnetron sputtering without substrate heating. We investigated the dependence of some properties for AlN thin film on sputtering conditions such as working pressure, $N_2$ concentration and RF power. XRD, Ellipsometer and AES has been measured to find out structural properties and preferred orientation of AlN thin films. Deposition rate of AlN thin film was increased with an increase of RF power and decreased with an increase of $N_2$ concentration. AES in-depth measurements showed that stoichiometry of Aluminium and Nitrogen elements were not affected by $N_2$ concentration. It has shown that low working pressure, low $N_2$ concentration and high RF power should be maintained to deposit AlN thin film with a high degree of (0002) preferred orientation.

• Journal of Sensor Science and Technology
• /
• v.17 no.5
• /
• pp.346-349
• /
• 2008

A metal-semiconductor-metal (MSM) ultraviolet (UV) photodetector (PD) is proposed as an effective UV sensing device for integration with a GaN n-channel MISFET on auto-doped p-type GaN grown on a silicon substrate. Due to the high hole barrier of the metal-p-GaN contact, the dark current density of the fabricated MSM PD was less than $3\;nA/cm^2$ at a bias of up to 5 V. Meanwhile, the UV/visible rejection ratio was 400 and the cutoff wavelength of the spectral responsivity was 365 nm. However, the UV/visible ratio was limited by the sub-bandgap response, which was attributed to defectrelated deep traps in the p-GaN layer of the MSM PD. In conclusion, an MSM PD has a high process compatibility with the n-channel GaN Schottky barrier MISFET fabrication process and epitaxy on a silicon substrate.