Single-wall carbon nanotubes and nanohorns were fabricated by means of a torch arc method in open air. A graphite target containing Ni/Y catalyst was used as a counterelectrode of the welding arc ...torch. The target was blasted away by the DC arc, and soot was deposited on the substrate placed downstream of the arc plasma jet. The deposited soot was observed with a transmittance electron microscope, revealing that the soot contained single-wall carbon nanotubes and nanohorns.
In this study, we used two types of carbon nanomaterials, arc-black (AcB) which has an amorphous structure and carbon nano-balloon (CNB) which has a graphitic structure as electrochemical capacitor ...electrodes. We made a coin electrode from these carbon materials and fabricated an electric double-layer capacitor (EDLC) that sandwiches a separator between the coin electrodes. On the other hand, RuO2 was loaded on these carbon materials, and we fabricated a pseudo-capacitor that has an ion insertion mechanism into RuO2. For comparison with these carbon materials, activated carbon (AC) was also used for a capacitor electrode. The electrochemical properties of all the capacitors were evaluated in 1M H2SO4 aqueous solution. As a result of EDLC performance, AcB electrode had a higher specific capacitance than AC electrode at a high scan rate (≥ 100 mV/s). In the evaluation of pseudo-capacitor performance, RuO2-loaded CNB electrode showed a high specific capacitance of 734 F/g per RuO2 weight.
The wide-ranging industrial application of graphene and related compounds has led researchers to devise methods for the synthesis of high quality graphene. We recently reported on the chemical ...synthesis, patterning, and doping of graphene films by the chemical exfoliation of graphite into graphene oxide (GO) with subsequent chemical reduction into graphene films 1, 2. Here, we describe a hybrid approach for the synthesis of reduced graphene sheets, where chemically derived GO was reduced by microorganisms extracted from a riverside near the University. Our procedure enabled the production of ~100 mu m sized reduced graphene sheets, which showed excellent Raman spectra associated with high quality reduced graphene. We give a detailed account of the relationship between the type of microorganisms and the properties of the resulting reduced graphene.
We have successfully grown carbon nanotubes (CNTs) by plasma-enhanced chemical vapor deposition (PECVD) using alcohol. When 0.01-wt% ferrocene was added to the alcohol, vertically aligned CNTs grew ...at 650degC. By contrast, a few CNTs and mostly carbon nanoparticles were obtained by pure alcohol PECVD even though the Fe catalyst was coated on Si substrates. Comparing this PECVD experiment with thermal alcohol CVD showed that only the PECVD method can be used to grow CNTs under the reported experimental conditions. To understand the plasma properties for CNT growth, particularly plasma species contained in a gas phase of alcohol plasma, the plasma was analyzed using optical-emission spectroscopy (OES) and quadrupole mass spectrometry (QMS). From the OES measurement, emission peaks from the excitation states of C 2 , CH, CHO, CH 2 O, CO, H, O 2 , C + , and CO + were identified, while the QMS measurement also showed the existence of H 2 , O, and CO. These results indicate that, in alcohol plasma, oxidants and reductants exist together and potentially promote/suppress CNT growth depending on the process conditions. The contribution of C x H y (x ges 1, y ges 3) radicals, which were produced by decomposition reactions in alcohol plasma as a CNT precursor, is discussed.
The arc-soot (AS) nano-carbon was synthesized by using arc discharge apparatuses which were the conventional arc apparatus and the new twin-torch-arc apparatus. AS synthesized with the conventional ...arc apparatus contained cocoon-like carbon nano-horn (CNH), dahlia-like CNH, and graphite ball. On the other hand, AS which was synthesized using the new twin-torch-arc apparatus contained mainly cocoon-like CNH and dahlia-like CNH, and contained a little graphite ball. The quality of dispersion was characterized and evaluated by the index of dispersion which was based on a diameter and a number density of catalyst particles. The electrocatalystic activity of the Pt/Ru catalysts was evaluated by the methanol-impregnated paper burning method. If the index of dispersion of the AS was high, then the AS burned violently. In the dispersion process, the optimum dispersion temperature obtained was 150
°C. Some MEAs of DMFC cell consisted of each Pt/Ru–AS catalyst which had different characteristics. It was observed that the power density increased with the index of dispersion. It was suggested that the power density of DMFC increased by 500% with a 350% increase in the index of dispersion. Pt/Ru–AS catalyst used AS, which was synthesized using the new twin-torch-arc apparatus, was better than Pt/Ru–AS catalysts using AS which were synthesized with the conventional arc apparatus to apply for the catalyst of DMFC.
Two hundred and eighty seven Japanese cases of drug induced liver injury were assessed by the diagnostic scale of the International Consensus Meeting (ICM). They were classified to the hepatocellular ...(55%), mixed (24%) and cholestatic (22%) type according to the type of liver injury. Five cases were diagnosed as ‘unrelated’, since the reaction occurred more than 15 days after stopping the drug. The remaining 282 cases were classified to 69 cases of ‘highly probable’, 170 cases of ‘probable’, 39 cases of ‘possible’, and four cases of ‘unlikely’. The cases with positive drug-lymphocyte stimulation test (DLST) and with eosinophilia distributed to higher scores. Although the diagnostic scale of the ICM was found to be also useful for Japanese cases, the modification of the scale including the data of DLST and eosinophilia together with some other modifications were recommended in the view of the present status of Japan. Using the modified diagnostic scale, the 287 cases were classified to 173 cases of ‘highly probable’, 102 cases of ‘‘probable’, 11 cases of ‘possible’, and one case of ‘unlikely’. Although the modified diagnostic scale seems better than the original one, further assessment of the modified scale using many Japanese cases is needed for the further improvement of the scale.
The effects of nano-structured carbon fillers fullerene C
60, single wall carbon nanotube (SWCNT), carbon nanohorn (CNH), carbon nanoballoon (CNB), and ketjenblack (KB) and conventional carbon ...fillers conductive grade and graphitized carbon black (CB) on conductivity (resistance), thermal properties, crystallization, and proteinase K-catalyzed enzymatic degradation of poly(
l-lactide) i.e., poly(
l-lactic acid) (PLLA) films were investigated. Even at low filler concentrations such as 1
wt%, the addition of SWCNT effectively decreased the resistivity of PLLA film compared with that of conventional CB, and PLLA–SWCNT film with filler concentration of 10
wt% attained the resistivity lower than 100
Ω
cm. The crystallization of PLLA further decreased the resistivity of films. The addition of carbon fillers, except for C
60 and CNB at 5
wt%, lowered the glass transition temperature, whereas the addition of carbon fillers, excluding C
60, elevated softening temperatures, if an appropriate filler concentration was selected. On heating from room temperature, cold crystallization temperature was determined mainly by the molecular weight of PLLA, whereas on cooling from the melt, the carbon fillers, excluding KB, elevated the cold crystallization temperature, reflecting the effectiveness of most of the carbon fillers as nucleating agents. Despite the nucleating effects, the addition of carbon fillers decreased the enthalpy of cold crystallization of PLLA on both heating and cooling. The addition of CNH, CNB, and CB elevated the starting temperature of thermal degradation of PLLA, whereas the addition of SWCNT reduced the thermal stability. Furthermore, the addition of C
60 and SWCNT enhanced the enzymatic degradation of PLLA, whereas the addition of KB and CNB disturbed the enzymatic degradation of PLLA. The reasons for the effects of carbon fillers on the physical properties, crystallization, and enzymatic degradation of PLLA films are discussed.
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