• The Korean Journal of Ceramics
• /
• v.2 no.4
• /
• pp.184-187
• /
• 1996

Diamod nucleation by mw assisted CVD was examined various conditions namely, (1) diamond nucleation on variour substrate materials, such as Si, cubic BN, pyrolytic BN and AIN, (2) AST(Activated species transport) method which promote nucleation of diamond on single crystal and polycrystalline alumina substrate was developed. (3) Effect of bias enhancement of nucleation on single crystalline Si was examined, and finally (4) DST (Double step treatment) method was developed to enhance diamond nucleation on Ni. In this method, we separated carbon diffusing process into Ni, carbon precipitating process from the inside of Ni and diamond precipitation process.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.5
• /
• pp.555-560
• /
• 2014

This study investigates the effect of sodium bicarbonate ($NaHCO_3$) on growth of S.dimorphus. $NaHCO_3$ concentration was varied from 0 to 2 g-C/L. As a result, the increase in concentration of $NaHCO_3$ up to 1.5 g-C/L increased dry weight of algae. The highest specific growth rate of S. dimorphus was $0.36day^{-1}$ which was obtained at concentration of 0.5 g-C/L $NaHCO_3$. pH showed a large variation range at the concentrations lower than 0.5 g-C/L $NaHCO_3$ whereas inorganic carbon, nitrate and phosphorus removal rates were almost same at the concentrations higher than 0.5 g-C/L $NaHCO_3$ (0.75, 1, 1.25, 1.5, 2 g-C/L $NaHCO_3$). Their average inorganic carbon, nitrate and phosphorus removal rate were 70 mg-C/L/d, 11.3 mg-N/L/d, and 1.6 mg-P/L/d, respectively. Thus, $NaHCO_3$ didn't effect on inorganic carbon, nitrate and phosphorus removal rate of S. dimorphus.

• Ocean and Polar Research
• /
• v.45 no.3
• /
• pp.103-111
• /
• 2023

To evaluate the impact of effluents from land-based fish farms on the coastal ocean of Wando, Korea, we analyzed inorganic nutrients, particulate organic carbon (POC), dissolved organic carbon (DOC), and colored dissolved organic matter (CDOM) in the effluent and influent of land-based fish farms during the summer (July) of 2021. The average concentrations of nutrients (Dissolved inorganic nitrogen, phosphorus, and silicate; DIN, DIP, and DSi, respectively) in the effluents of this study area were 17±3.7 μM, 1.4±0.7 μM, and 14±1.6 μM, respectively. The average concentrations of POC and DOC were 37±22 μM and 81±13 μM, respectively, with POC accounting for about 30% for total organic carbon in effluents. The Reduced Dissolved Inorganic Nitrogen/Total Dissolved Inorganic Nitrogen ratio (0.7), potential short-period index, indicates that the discharge of nutrients excreted by the fish and unconsumed feed into coastal water results in such nutrients being deposited and accumulated in the sediment. Subsequently, this continuous accumulation triggers the release of ammonium ions during organic matter decomposition, and the ammonium-enriched waters that encroach on fish farms as influent seem to be due to the diffusion of high concentrations of ammonium from bottom sediment. Furthermore, we used fluorescence indices to examine the characteristics of organic matter sources, obtaining mean values of 1.54±0.19, 1.06±0.06, and 1.56±0.06 for the humification index, biological index, and fluorescence index, respectively, in the effluent. These results indicate that the organic matters had an autochthonous origin that resulted from microbial decomposition, and such organic matters were rapidly generated and removed by biological activity, likely supplied from the sediment. Our results suggest that the effluent from land-based fish farms could be a potential source of deoxygenation occurrence in coastal areas.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.488.2-488.2
• /
• 2014

Carbon-based materials such as carbon nanotubes and graphene have emerged as promising building blocks in applications for nanoelectronics and energy devices due to electrical property, ease of processability, and relatively inert electrochemistry. In recent years, there has been considerable interest in core-shell nanomaterials, in which inorganic nanowires are surrounded by inorganic or organic layers. Especially, carbon encapsulated semiconductor nanowires have been actively investigated by researchers in lithium ion batteries. We report a method to synthesize silicon nanowire (SiNW) core/carbon shell structures by chemical vapor deposition (CVD), using methane (CH4) as a precursor at growth temperature of $1000{\sim}1100^{\circ}C$. Unlike carbon-based materials synthesized via conventional routes, this method is of advantage of metal-catalyst free growth. We characterized these materials with FE-SEM, FE-TEM, and Raman spectroscopy. This would allow us to use these materials for applications ranging from optoelectronics to energy devices such as solar cells and lithium ion batteries.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07b
• /
• pp.1451-1454
• /
• 2005

We report effects of inorganic binder on the emission properties of CNT paste for low cost and high low-cost and large area field emission devices or displays. Two types of photosensitive carbon nanotube (CNT) paste were formulated by using of glass frit and spin on glass (SOG) as an inorganic binder and investigated their emission properties according to inorganic binders and firing conditions.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.11
• /
• pp.20-25
• /
• 2007

In this paper, It was reported the dielectric constant in organic inorganic hybrid silica material such as SiOC film modeling of bond structure by annealing in organic properties. The organic inorganic hybrid silica material were deposited using bis-trimethylsilymethane (BTMSM, [(CH3)3Si]2CH2) and oxygen gas precursor by a plasma chemical vapor deposition (CVD). The organic inorganic hybrid silica material have three types according to the deposition condition. The dielectric constant of the films were performed MIS(Al/Si-O-C film/p-Si) structure. The C 1s spectra in organin inorganic silica materials with the flow rate ratio of O2/BTMSM=1.5 was organometallic carbon with the peak 282.9 eV by XPS. It means that organometallic carbon component is the cross-link bonding structure with good stability. The dielectric constant was the lowest at annealed films with cross-link bonding structure.

• Journal of the Korean Ceramic Society
• /
• v.50 no.1
• /
• pp.1-17
• /
• 2013

Since their first discovery, carbon nanotubes (CNTs) have become a material central to the field of nanotechnology. Owing to their splendid physical, structural and chemical properties, they have the potential to impact a wide range of applications, including advanced ceramics, nanoelectronic devices, nanoscale sensors, solar cells, battery electrodes, and field emitters. This review summarizes the synthetic methods of preparing CNTs and focuses on the chemical vapor deposition (CVD) method, especially catalytic CVD. In order to stabilize and disperse the catalyst nanoparticles (NPs) during synthesis, zeolite was implemented as the template to support metal-containing NPs, so that both CNTs in the bulk and on a 2D substrate were successfully synthesized. Despite more challenges ahead, there is always hope for widespread ever-new applications for CNTs with the development of technology.

• Carbon letters
• /
• v.4 no.2
• /
• pp.64-68
• /
• 2003

A study on the electrosorption of uranium ions onto a porous activated carbon fiber (ACF) was performed to treat uraniumcontaining lagoon sludge. The result of the continuous flow-through cell electrosorption experiments showed that the applied negative potential increased the adsorption kinetics and capacity in comparison to the open-circuit potential (OCP) adsorption for uranium ions. Effective U(VI) removal is accomplished when a negative potential is applied to the activated carbon fiber (ACF) electrode. For a feed concentration of 100 mg/L, the concentration of U(VI) in the cell effluent is reduced to less than 1 mg/L. The selective removal of uranium ions from electrolyte was possible by the electrosorption process.

• Carbon letters
• /
• v.26
• /
• pp.74-80
• /
• 2018

The South Korean Ministry of the Environment has revised the laws relating to the management of interior air quality for multiple use facilities, and recommends maintaining carbon dioxide ($CO_2$) concentration in passenger vehicles below 1000 ppm during operation in urban areas of large cities. However, the interior $CO_2$ concentration of passenger vehicles can rapidly increase and exceed 5000 ppm within 30 min, as observed when two passengers are traveling in urban areas of the South Korean city of Jeonju with the air conditioner blower turned off and the actuator mode set to internal circulation mode. With four passengers, $CO_2$ concentration can reach up to 6000 ppm within 10 min. To counter this, when the actuator is set to external mode, $CO_2$ concentration can be maintained below 1000 ppm, even after a long period of running time. As part of the air conditioning system, alkali-treated activated carbon fiber filters are considered to be far superior to the commercial non-woven filters or combination filters currently commonly in use.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.1385-1390
• /
• 2006

Concrete structure can be deteriorated by ingress of moisture and aggressive agents. To maintain the sound performance of concrete structure during the service life, it needs to protect concrete from ingress of moisture and aggressive agents before arising deterioration of concrete. Protection of concrete is possible by surface treatment. In this study, durability of the functional nano composite inorganic activated carbon based coatings which can provide a barrier against the ingress of moisture or aggressive ions to concrete is discussed. For the durability evaluation of the coatings, fine void structure evaluation test, chloride penetration acceleration test, accelerated carbonation test, freezing and thawing test, and the accelerated test of chemical erosion are conducted. As the result of this study, the functional nano composite inorganic activated carbon based coatings which became one formed complex compound with adsorption and porosity on concrete surface, had an effect on the function of far infrared radiation, antimicrobial action, air cleaning, airing assurance, and the interception of moisture of deterioration factor, chloride ion, carbon dioxide, sulfate, and so on.