• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.210-210
• /
• 2011

The effects of CH2F2 and N2 gas flow rates on the etch selectivity of silicon nitride (Si3N4) layers to extreme ultra-violet (EUV) resist and the variation of the line edge roughness (LER) of the EUV resist and Si3N4 pattern were investigated during etching of a Si3N4/EUV resist structure in dual-frequency superimposed CH2F2/N2/Ar capacitive coupled plasmas (DFS-CCP). The flow rates of CH2F2 and N2 gases played a critical role in determining the process window for ultra-high etch selectivity of Si3N4/EUV resist due to disproportionate changes in the degree of polymerization on the Si3N4 and EUV resist surfaces. Increasing the CH2F2 flow rate resulted in a smaller steady state CHxFy thickness on the Si3N4 and, in turn, enhanced the Si3N4 etch rate due to enhanced SiF4 formation, while a CHxFy layer was deposited on the EUV resist surface protecting the resist under certain N2 flow conditions. The LER values of the etched resist tended to increase at higher CH2F2 flow rates compared to the lower CH2F2 flow rates that resulted from the increased degree of polymerization.

• Textile Coloration and Finishing
• /
• v.21 no.1
• /
• pp.30-37
• /
• 2009

Studies on plants such as lotus leaf suggested that dual-scale structure could contribute to super-hydrophobicity. We introduced super-hydrophobicity onto poly(ethylene terephthalate)(PET) fabric with dual-scale structure by assembling $TiO_2$ nano sol. PET fabric was treated with $TiO_2$ sol, water-repellent agent using various parameters such as particle size, concentration. Morphological changes by particle size were observed using field emmission scanning electron microscopy(FE-SEM) and AFM measurement, contact angle measurement equipment. The contact angle of water was about 138.5$^{\circ}$, 125.8$^{\circ}$, 125.5$^{\circ}$ and 108.9$^{\circ}$ for PET fabric coated with 60.2nm, 120.1nm, 200nm and 410.5nm $TiO_2$ particles, compared with about 111.5$^{\circ}$ for PET fabric coated with water repellent. When we mixed particle sizes of 60.2nm and 120.1nm by 7:3 volume ratio, the contact angle of water was about 132.5$^{\circ}$. And we mixed particle sizes of 60.2nm and 200nm by 7:3 volume ratio, the contact angle of water was about 141.8$^{\circ}$. Also we mixed particle sizes of 60.2nm and 410.5nm by 7:3 volume ratio, the best super-hydrophobicity was obtained. In this paper, we fabricated various surface structures to the water-repellent surfaces by using four types of $TiO_2$ nano-particles, and we found that the nanoscale structure was very important for the super-hydrophobicity.

• Journal of the Korean Geographical Society
• /
• v.41 no.2 s.113
• /
• pp.227-243
• /
• 2006

This paper reviews how electronic media technologies involve and produce time-space dimensions in geometrical spaces, focusing on four theoretical perspectives: van Dijk's dual structure of networks as scale extension and reduction; Latour's actor-networks as fluid and hybrid networks; Virilio's dromospherical time as global media vectors; and Castells' timeless time as non-sequential flows. In these four theoretical perspectives, we can see that electronic media technologies involve different and multiple time-space dimensions in geometrical media spaces: from the two-dimensional spaces (surfaces) of concentric circles, through the one-dimensional spaces (lines) of actor-networks to the zero-dimensional spaces (points) of dromospherical time and finally to the multi-dimensional spaces (hypertexts) of timeless time. The paper concludes by suggesting that we need to explain electronic media spaces not only in terms of geometrical media spaces but also in terms of geographical media spaces in order to understand the ways in which electronic media spaces are dis/embedded in geographical spaces.

• Composites Research
• /
• v.25 no.3
• /
• pp.76-81
• /
• 2012

Atmospheric pressure plasma treatment on carbon nanotube (CNT) surfaces was performed to modify reinforcement effect and interfacial adhesion of carbon fiber reinforced CNT-phenolic composites. The surface changes occurring on CNT treated with plasma were analyzed by using Fourier transform infrared spectroscope (FT-IR). The significant improvement of wettability on CNT was confirmed by static contact angle test after plasma treatment. Such plasma treatment resulted in a decrease in the advancing contact angle from $118^{\circ}$ to $60^{\circ}$. The interfacial adhesion between carbon fiber and CNT-phenolic composites increased by plasma treatment based on apparent modulus test results during quasi-static tensile strength. Furthermore, the proposed database offers valuable knowledge for evaluating interfacial shear strength (IFSS).

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.458-458
• /
• 2010

The process window for the etch selectivity of silicon nitride ($Si_3N_4$) layers to extreme ultra-violet (EUV) resist and variation of line edge roughness (LER) of EUV resist were investigated durin getching of $Si_3N_4$/EUV resist structure in a dual-frequency superimposed capacitive coupled plasma (DFS-CCP) etcher by varying the process parameters, such as the $CH_2F_2$ and $N_2$ gas flow rate in $CH_2F_2/N_2$/Ar plasma. The $CH_2F_2$ and $N_2$ flow rate was found to play a critical role in determining the process window for infinite etch selectivity of $Si_3N_4$/EUV resist, due to disproportionate changes in the degree of polymerization on $Si_3N_4$ and EUV resist surfaces. The preferential chemical reaction between hydrogen and carbon in the hydrofluorocarbon ($CH_xF_y$) polymer layer and the nitrogen and oxygen on the $Si_3N_4$, presumably leading to the formation of HCN, CO, and $CO_2$ etch by-products, results in a smaller steady-state hydrofluorocarbon thickness on $Si_3N_4$ and, in turn, in continuous $Si_3N_4$ etching due to enhanced $SiF_4$ formation, while the $CH_xF_y$ layer is deposited on the EUV resist surface. Also critical dimension (and line edge roughness) tend to decrease with increasing $N_2$ flow rate due to decreased degree of polymerization.

• Journal of Aerospace System Engineering
• /
• v.16 no.5
• /
• pp.86-93
• /
• 2022

Generally, a deployable solar panel is used primarily to achieve sufficient power output to perform the mission. However, temperature distribution on the antenna reflector may increase due to the shading effect induced by the presence of the deployable solar panels. Appropriate thermal design is critical to minimize the thermal deformation of the mesh antenna reflector in harsh on-orbit thermal environments to ensure remote frequency (RF) performance. In this paper, we proposed a dual-surface primary reflector consisting of a mesh antenna and a flexible fabric membrane sheet. This design strategy can contribute to thermal stabilization by using a flexible solar panel on the rear side of membrane sheet to reduce the temperature distribution caused by the deployable solar panel. The effectiveness of the mesh antenna design strategy investigates through on-orbit thermal analysis.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.93.2-94
• /
• 2003

In our previous studies, we selected three antagonistic bacteria, KJ1R5, KJ2C12, and KJ9C8 against Phytophthora capsici, the casual agent of Phytophthora blight of pepper. For elucidating production, root colonization, and total microbial activity were investigated. The dual culture assay was accomplished to elucidate existence of antibiotics. In this assay, any antagonistic bacteria did not inhibit growth of six important fungal plant pathogens, suggesting that these antagonists do not produce antibiotics. root surface or rhizosphere soil colonizations were examined with spontaneous rifampicin-resistant mutants equal to antagonistic ability of wild types. KJ2C12 colonized consistently rhizosphere soil while yellowish colonies of KJ1R5 and KJ9C8 well colonized root surfaces and rhizosphere soil. Total microbial activity in pots treated with the antagonistic bacteria was measured using fluorescein diacetate hydrolysis. total microbial activity of three antagonistic bacteria treatments was significantly higher than that of buffer-treated control until 4days after treatment. However, total microbial activity of treatment of three antagonistic bacteria decreased after 7 days. These results indicate that the antagonistic bacteria, KJ1R5 and KJ9C8 colonized and protected roots well against Phytophthora blight of pepper through competition of infection courts, especially competitions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.11
• /
• pp.725-728
• /
• 2016

We investigated the characterizations of carbon films fabricated by dual magnetron sputtering under various film thickness for the electrodes in TCO-less DSSC (dye-sensitized solar cells). Carbon films prepared at various conditions were exhibited smooth and uniform surfaces without defects. Also, the rms surface roughness of carbon films was decreased from 2.25 nm to 1.0 nm with the increase of film thickness. The sheet resistance as the electrical properties are improved from $11.2{\times}10^{-3}$ to $2.28{\times}10^{-3}$ with the increase of film thickness. In the results, the performance of TCO-less DSSC critically depended on the film thickness of working electrodes, indicating the conductivity of carbon films.

• Journal of the Korean institute of surface engineering
• /
• v.45 no.6
• /
• pp.284-288
• /
• 2012

A study on microstructure control of multi-phase steel have been implemented to higher strength with improved formability. However, it is well known that the high strength of steel are susceptible to hydrogen embrittlement. The mechanisms of hydrogen embrittlement is caused by complex interactions. In this paper, the test specimens were fabricated to 5 type of 590DP steels at different levels of volume faction. The hydrogen charging was conducted by electrochemical hydrogen-charge method with varying charging time. The relationship between hydrogen concentration and volume fraction of 590DP steel was established by SP test and SEM-fractography. It was shown that the hydrogen amounts charged in 590DP steels increased with increasing the volume faction of austenite. The maximum loads of the 590DP steels in SP test were sharply decreased with increasing hydrogen charging time. The results of SEM-fractography investigation showed typical brittle-fracture surfaces for hydrogen-charged 590DP steels.

• Aerospace Engineering and Technology
• /
• v.12 no.1
• /
• pp.207-212
• /
• 2013

To investigate the possibility of using artificial means for the control of shear layers in swirl jets, a shear excitation device is introduced. The device consists of co-centric dual nozzles with internal lobes (i.e., convex surfaces) of small height to induce disturbance. The number of convexities can be varied to produce the various modes in azimuthal direction. The acquired velocity data of the swirling jets, with and without the lobes, are numerically simulated in 2-D contour plots and 3-D particle trace plots. The results are compared with the baseline (i.e., no excitation case) at various excitation modes. Conclusively it is observed that the artificial excitation method is effective in the control of the vortical structure in swirling jets.