• Journal of the Korean Recycled Construction Resources Institute
• /
• v.1 no.3
• /
• pp.181-188
• /
• 2013

This paper is to investigate experimentally an effect of carbon amino silica black-superplasticizer(CASB-SP)on the engineering properties and chromaticity of black color concrete with 0.45 of W/C(water to cement). CASB-SP and carbon black were applied for pigment of the concrete. To prevent efflorescence of concrete, four different water repellent agents were also applied. As results, it was found that use of CASB-SP increased the slump and air contents. Furthermore, the use of CASB-SP increased the compressive strength. As CASB-SP dosages increased, chromaticity was well developed. For the effect of water repellent agent, the use of epoxy type was effective for protection from efflorescence. Based on test results, it was evaluated that 0.5% of CASB-SP effectively improve the concrete quality as well as enhance the chromaticity with proper dosage.

• Carbon letters
• /
• v.14 no.1
• /
• pp.55-57
• /
• 2013

The development of hollow carbon balls by $CO_2$ oxidation of two types of carbon blacks was studied. Super P (SP) and Denka Black (DB) were used for this study. Specific surface area (SSA), structural parameters, and microstructures were examined using Brunauer, Emmett and Teller apparatus, X-ray diffraction spectroscopy, and transmission electron microscope (TEM), respectively. The SSAs of both oxidized carbon blacks increased after oxidation. The SSAs of raw DB and SP were 73 $m^2/g$ and 60 $m^2/g$, respectively. Maximum SSAs of oxidized DB and SP were 152 $m^2/g$ and 253 $m^2/g$, respectively. The $d_{002}$ of DB and SP showed almost no change after oxidation. The Lc of raw DB ($38{\AA}$) and SP ($19{\AA}$) increased with increasing weight loss. The $L_c$ of SP increased up to $254{\AA}$ at 96% weight loss. The SSA increased about twice in DB (148 $m^2/g$) and about four times in SP (254 $m^2/g$) after 3 h oxidation compared with the original carbon blacks. Through TEM observation the outer parts of the oxidized carbon blacks showed a rigid shell structure and the inner parts looked empty. Generally it looked like an angular soccer ball, so we named it 'hollow carbon ball'. It is expected that the hollow carbon ball can be used as catalyst supports.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.2
• /
• pp.467-470
• /
• 2009

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.14 no.1
• /
• pp.27-32
• /
• 2004

The diamond-like carbon (DLC) films were deposited on the Si (100) wafer by a rf-PECVD method as a function of the mixture rate of methane-hydrogen gas and bias voltage. The bonding structure and mechanical properties of these deposited DLC films were investigated using FT-IR, Raman, and nano-indenter. The deposition rates of DLC films increased with increased flow rate of methane in the gas mixtures and increased bias voltage. The $sp^3/sp^2$ bonding ratio of carbon in thin film and the hardness increased with increasing flow rate of hydrogen in the gas mixtures and increasing bias voltage.

• Microbiology and Biotechnology Letters
• /
• v.32 no.2
• /
• pp.123-127
• /
• 2004

Pseudomonas sp. MBEL21 was newly isolated from soil samples and found to accumulate medium-chain-length Polyhydroxyalkanoates(MCL-PHAs) using oleic acid as a sole carbon source. Among the various nutrient limiting conditions examined, including nitrogen, sulfur and phosphorus, only phosphorus limitation supported the accumulation of MCL-PHAs up to 15 wt％ of dry cell weight in flask cultures. MCL-PHAs produced by Pseudomonas sp. MBEL21 was mainly composed of 3-hydroxy-5-cis-tetradecenoate. Fed-batch culture of Pseudomonas sp. MBEL21 by novel feeding strategies based on cell growth charcteristics was carried out under phosphorus limitation using oleic acid as a sole carbon source. The final cell concentration and PHA content of 82 g/L and 28 wt％, respectively, were obtained. Furthermore, PHA consisted of MCL-hydroxyalkanoates and 3-hydroxybutyrate could be produced using olive oil as a sole carbon source.

• Journal of Ecology and Environment
• /
• v.29 no.5
• /
• pp.433-438
• /
• 2006

To elucidate the mechanisms by which algal food quality affect Daphnia growths, we measured carbon incorporation rates and respiration rates of Daphnia magna with Cryptomonad Rhodomonas minuta, green algae Scenedesmus acutus and cyanobacteria Synechococcus sp. with varying physiological states as food. Carbon assimilation rates were high with R. minuta and S. acutus and low with Synechococcus sp. showing a similar pattern to the growth rate pattern. There was no clear difference among respiration rates of three algal species. Carbon assimilation rates and respiration rates of D. magna appeared to be independent on Molar C:P ratios in algal foods. Carbon growth efficiencies (incorporated carbon per assimilated carbon amount) were lower when D. magna fed with Synechococcus sp. than fed with R. minuta or S. acutus. Analysis of variance results show that carbon assimilation rates which were sum of incorporation and respiration rates and carbon growth efficiencies were only dependant on species affiliation. Overall, our results showed that algal species with varying ${\omega}3$ polyunsaturated fatty acid content led different carbon incorporation rates and overall carbon assimilation rates of D. magna.

• Journal of the Korean Vacuum Society
• /
• v.9 no.2
• /
• pp.122-129
• /
• 2000

Field emission behavior from vitreous carbon powders deposited on Mo coated glass by electro-phoretic method was investigated. Although the vitreous carbon has only $sp^2$ hybridized carbon bond, we could observe an excellent field emission behavior. Reproducible electron emission was observed without initiation process which is known to be needed in most carbon cathode materials. Critical electric field for electron emission was in the range from 3 to 4 MV/m. The effective work function was estimated to be about 0.06 eV, as obtained from the slope of Fowler-Nordheim plot. The stability of the emission behavior characterized by repeated I-V measurements, was much superior to the Si tips. We observed the possibility of full area light emission in vitreous carbon materials. This results showed that the field emission is not intimately related to the $sp^3$ hybridization of carbon, but the electrical properties of cathod/electrode interface or the conductivity of the cathode materials which required for the electron transport to the cathode surface.

• Journal of the Korean institute of surface engineering
• /
• v.29 no.5
• /
• pp.549-555
• /
• 1996

Diamond Like Carbon film is amorphous film which is considered to consist of three coordinate graphite structure and tetrahedron coordinate diamond structure. Its hardness, thermal conductivity and chemical stability are nearly to one of diamond. It is well known to become semi-conductor by doping of inpurity. In this study Diamond Like Carbon film was synthesized by Microwave Plasma CVD in the gas mixture of hydrogen-methan-nitrogen and doped of nitrogen on the single-crystal silicon or silica glass. The temperature of substrate and nitrogen concentration in the gas mixture had an effect on the bonding state, structural properties and conduction mechanism. The surface morphology was observed by Scanning Electron Microscope. The strucure was analyzed by laser Raman spectrometry. The bonding state was evaluated by electron spectroscopy. Diamond Like Carbon film synthesized was amorphous carbon containing the $sp^2$ and $sp^3$ carbon cluster. The number of $sp^2$ bonding increased as nitrogen concentration increased from 0 to 40 vol% in the feed gas at 1233K substrate temperature and at $7.4\times10^3$ Pa. Increase of nitrogen concentration made Diamond Like Carbon to be amorphous and the doze of nitragen could be controlled by nitrogen concentration of feed gas.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.1
• /
• pp.117-121
• /
• 1997

The glucose isomerase productivity of Arthrobacter sp. L-3 was studied. glucose plus xylose showed higher productivity of glucose isomerase than any other carbon sources. Yeast extract showed higher productivity of glucose isomerase than any other nitrogen sources. The optimum culture time for the production of glucose isomerase was 40hrs.

• Transactions on Electrical and Electronic Materials
• /
• v.2 no.3
• /
• pp.1-6
• /
• 2001

A simulation method is proposed to study the amorphous structure of carbon nitride. The material properties of a non-uniform nitrogen distribution in an amorphous CN matrix can be studied. The cohesive energy of a group of randomly generated atoms can be minimized to find the relative positions of atoms. From the calculated configuration of atoms, many properties of amorphous carbon nitride can be calculated such as bulk modulus, P-V curve, sp$^3$/sp$^2$ ratio of carbon, and vibrational spectra. The calculation shows that the cohesive energy of non-uniform nitrogen distribution is lower than that of a uniform distribution. This may suggest that the regular structure of carbon nitride can at most be metastable. It is not easy to incorporate nitrogen atoms into a carbon matrix.