• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.4
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• pp.145-152
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• 2015

In this work, we were investigated the effect of the additive gases on the relationship between bonding structure and mechanical properties of the deposited films when the DLC films were deposited on Si-wafer by the rf-PECVD method with the addition of small amounts of carbon dioxide and nitrogen to the mixture gas of methane and hydrogen. The deposition rate of the films increased as the rf-power increased, while it decreased with increasing the amount of additive gases. Also, as the carbon dioxide gas increased, the hydrogen content in the films decreased but the $sp^3/sp^2$ ratio of the films increased. In case of nitrogen gas, the hydrogen content decreased, however the $sp^3/sp^2$ ratio and nitrogen gas flow rate did not show a specific tendency.

• Journal of the Korean Vacuum Society
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• v.11 no.1
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• pp.8-15
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• 2002

Tetrahedral amorphous carbon(ta-C) films were deposited by the filtered vacuum arc(FVA) process. The FVA process has many advantages such as high ionization ratio and the ion energy, which is suitable for dense amorphous carbon film deposition. However, the energy of the carbon ion cannot be readily controlled by manipulating the arc source parameters. In order to control the film properties in wide range, we investigated the dependence of the film properties on the substrate bias voltage. The mechanical properties and the density of the film exhibit the maximum values at about -100 V of the bias voltage. The maximum values of hardness and density were respectively 54$\pm$3 GPa and 3.6$\pm$0.4 g/㎤, which are 3 to 5 times higher than those of the films deposited by RF PACVD or ion beam process. The details of the atomic bond structure were analysed by Raman and NEXAFS spectroscopy. The change in the film properties for various bias voltages could be understood in the view of the $sp^2$ and $sp^3$ bond fraction in the deposited films.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.433-439
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• 1999

Among microorganisms isolated from soil, YJ-66 strain was the best producer of flocculant and was examined for flocculating ability in the active carbon and CaCl2. YJ-66 strain was the best producer of flocculant and was examined for flocculating ability in the active carbon and CaCl2. YJ-66 strain was identified to be a species belonging to the genus Achromobacter. The optimum culture condition for production of bioflocculant with the isolated strain was for 72hrs at 3$0^{\circ}C$ and pH7.5. The favorable carbon, nitrogen sources and inorganic salts for production of the flocculant were sucrose, peptone, MgSO4 and KH2PO4, whose optimal concentrations were 2%. 0.067%, 0.1% and 0.1%, respectively. Addition of the carbon and inorganic salts significantly increased the production of flocculant. Compositions of optimized culture medium for bioflocculant production by Achromobacter sp. YJ-66 were 2% sucrose, 0.067% peptone, 0.1% MgSO4 and 0.1% KH2PO4 in initial pH 7.5 during at 3$0^{\circ}C$ for 72hrs.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1017-1024
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• 2017

Carbon thin films were deposited by HiPIMS(High Power Impulse Magnetron Sputtering). The properties and microstructures of carbon thin film were investigated with power, pressure, bias voltage and duty cycle. As the HiPIMS power increased, the deposition thickness increased and the surface tended to be rough. The increase in pressure also tended to make the surface rough, but the deposition thickness was not proportional to the pressure. As the bias voltage increased, the surface roughness became worse, the deposition thickness increased and then decreased from the critical bias voltage. Changes in the duty cycle have caused problems such as arcing, which is affected by the chamber structure and the size of the target. The $sp^2/sp^3$ fractions of thin films were estimated by XPS and it was confirmed that the fraction of thin films made by HiPIMS were larger than the fraction of thin films made by DC sputtering.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.214-217
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• 1993

Carbon monoxide dehydrogenase (CO-DH) was found to be present in Acinetobacter sp. strain JC1 grown on CO and also on methylotrophic and heterotrophic substrates, except for pyruvate and nutrient broth. The amounts of CO-DH in cells grown on methylamine, glucose, galactose, and succinate were comparable to that of the CO-grown cells. CO-DH activity, however, was onot deteted by the dye-linked assay method in cell extracts prepared from cells grown on organic substrates, except on ethanol and succinate. THe activity was detected when the CO-DH was stained by activity using CO as a substrate. CO-DHs in cells grown on different substrates were found to be identical in immunological properties.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.452-457
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• 1999

Several bacterial strains utilizing crude oil as their sole carbon and energy sources were isolated from marine. One of the strains named KCL-1 showed the highest degradative activity for crude oil and the best growth rate. This strain was identified as a Klebsiella sp. based on the morphological, biochemical, and physiological characteristics. The optimum cultural conditions were as follows; $32^{\circ}C$~$37^{\circ}C$ for temperature and 7.0 for initial pH. Additionally, the optimal concentration of sodium chloride was 3.0%, indicating that this strain was derived from seawater. KCL-1 could use several kinds of n-alkane hydrocarbons from octadecane to hexacosane as a sole carbon source. The degradation of crude oil by KCL-1 was stimulated by addition of octadecane in the culture. The emulsifying activity by KCL-1 was highest after 3 days of cultivation under the condition of 3.0% sodium chloride, pH 7.0 and $37^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.42 no.4
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• pp.179-185
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• 2009

Diamond-like carbon(DLC) films were deposited by linear ion source(LIS)-physical vapor deposition method changing the anode voltages from 800 V to 1800 V, and characteristics of the films were investigated using residual stress tester, nano-indentation, micro raman spectroscopy, scratch tester and Field Emission Scanning Electron Microscope(FE-SEM). The results showed that the residual stress and hardness increased with increasing the ion energy up to anode voltage of 1400 V. It was also found that the content of $SP^3$ carbon increased with increasing the anode voltage $SP^3/SP^2$ ratio through investigation of $SP^3/SP^2$ ratio by the micro-raman analysis. From these results, it can be concluded that the physical properties of DLC films such as residual stress and hardness are increased with increasing the anode voltage. These results can be explained that 3-dimensional cross-links between carbon atoms and Dangling bond are enhanced and the internal compressive stress also increased with increasing the anode voltage. The optimal anode voltage is considered to be around 1400 V in these experimental conditions.

• Carbon letters
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• v.9 no.1
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• pp.17-22
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• 2008

A carbon nanotube (CNT) of diameter ~20 nm has been synthesized by spray pyrolysis of turpentine oil using Ni/Fe catalyst. Pellet of CNTs has been used as a target to produce semiconducting carbon thin film of band gap 1.4 eV. Presence of oxygen pressure in the pulse laser deposition (PLD) chamber helped to control the $sp^3/sp^2$ ratio to achieve the desired band gap. Results are discussed with the help of Raman spectra, SEM TEM micrographs and optical measurements suggest that semiconducting carbon thin film deposited by PLD technique has retained its nanotubes structure except that its diameter has increased from 20 nm to 150 nm.

• KSBB Journal
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• v.26 no.1
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• pp.57-61
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• 2011

The principal objective of this study was to determine the optimal conditions for the production of biosurfactant by the indigenous bacterium, Pseudoalteromonas sp. HK-3, originating from oil-spilled areas. The relationship between total biosurfactant production and the factors affecting biosurfactant production were evaluated by statistical analysis using SPSS software. The effects of various supplemental carbon sources (e.g., glucose, dextrose, mannitol, citrate, acetate) on the maximal production of biosurfactant by the test culture of Pseudoalteromonas sp. HK-3 was then evaluated. As a result, mannitol was found in this study to be the best supplemental carbon source for the production of biosurfactant. A spot inoculation of crude cultural liquid containing the HK-3 cells generated the largest clear zone, whereas only small clear zones appeared around the spots inoculated with either supernatant only or cell pellets following centrifugation. Our results demonstrated that the HK-3 test culture supplemented with 2% mannitol at an initial pH of 6 generated the maximal amount of biosurfactant within 72 h of incubation.

• Journal of Environmental Health Sciences
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• v.11 no.2
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• pp.65-75
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• 1985

Microorganisms capable of utilizing diaminododecane containing amine groups diterminally were isolated from the soil by enrichment culture. One strain of these isolated strain, designated as EL-0112L, was selected for this study. The results of this study were as follows. 1. This isolated strain EL-0112L was identified as Microbacterium, from the results of morphological, cultural, and biochemical tests. This isolated strain was named temporarily Microbacterium sp. EL-0112L for convenience. 2. Microbacterium sp. EL-0112L was tested for ability to utilize different kinds of substitued alkanes containing cyan, amine, chloro, and thiol groups(monoterminally or diterminall substituted) as carbon source. Pentamethylenediamine, hexamethylenediamine, n-decane, laurylamine, and alkane derivatives containing cyan, chloro, and thiol groups were not utilized by Microbacterium sp. EL-0112L. 3. The alkane derivatives that did not serve as growth substrates were tested further in oxidation tests using resting cell preparation of Microbacterium sp. EL-0112 L. Alkane derivatives containing cyan, chloro, thiol groups, and n-decane were oxidized by Microbacterium sp. EL-0112 L. It is possible that this isolated strain is also able to degrade their substituted counterparts since they are structually similar to diaminododecane. The remarkable substrates that were being oxidized were dichlorodecane, and 1-dodecanethiol. Microbacterium sp. EL- 0112L could not oxidize pentamethylenediamine, and hexamethylenediamine. 4. The metabolic products formed from diaminododecane by Microbacterium sp. EL-0112 L were acid compound containing carboxyl group and not containing amine group. On the thin layer chromatography, Rf values of these metabolic products were different from that of the product formed by Corynebacterium sp. EL-0112L. These results suggested the specificity of diaminododecane as carbon source.