Hydroquinone is known to show an oxidation-reduction reaction. Active carbon felt with adsorbed hydroquinone shows higher capacitance than normal activated carbon does. Adsorbed hydroquinone shows a rapid oxidation-reduction reaction that can match a capacitor’s rapid charge and discharge. Furthermore, active carbon felt with adsorbed hydroquinone has longer-term stability than normal active carbon felt has, as demonstrated using cyclic voltammetry and constant current electrolysis.
This study investigated the validity of a wire mesh catalyst support. The wire mesh was formed from JSE20-5USR stainless steel foil subjected to expansion processing. In a hydrogen atmosphere, an iron-aluminum intermetallic compound was deposited on the wire mesh surface using heat treatment, thereby producing fine aluminum oxide whiskers on the wire mesh surface. Subsequently, Pt and/or Pd was coated directly onto the whiskers. Structures of catalysts containing Pt and/or Pd were examined using XRD and SEM. The developed catalysts were applied to a burner that was fueled by vaporized kerosene-air mixtures. The combustion gases' chemical components were measured to evaluate the developed catalysts' activity. The same loading catalyst with Pt showed higher activity than that with Pd. Formation of either a catalyst loaded with Pt or Pt supported on a Pd layer is beneficial for reducing CO and NOx emissions in combustion gases and for maintaining stable combustion. This wire mesh catalyst is applicable for practical catalytic combustors of kerosene fuel. It presents particular advantages of good design flexibility and low pressure drop.
For this study, single-crystal and polycrystalline diamond films with different boron contents were synthesized in a hot-filament chemical vapor deposition (CVD) apparatus to evaluate the mechanical properties of these films. Boron was added to the diamond by introducing B(CH3)3 :trimethyl boron diluted to 1000 ppm with hydrogen into the diamond-synthesis atmosphere. The synthesized diamond film's crystallinity was evaluated using Raman spectroscopy. The Hertz fracture strength was measured using a diamond-ball indenter. Furthermore, the wear resistance of the film was evaluated using a wear testing machine. The results indicate that the crystallinity of the single-crystal diamond film increased concomitantly with increasing boron content. Furthermore, the Hertz fracture strength increased by 20% with the addition of boron. Results clarified that the wear volume of polycrystalline diamond film decreased to approximately one-third its usual value by the addition of boron. These results show that the mechanical properties of boron-doped diamond films can be improved considerably by adding an appropriate amount of boron.
A method for addition of electrolytically generated bromine was applied for determination of 10-100 g m−3 of 2-butyne-1,4-diol in a nickel-plating solution. Distinct from existing methods, this method generates bromine electrolytically from a KBr solution before each analysis. Amounts of bromine generated using electrolysis agreed with the theoretical value using 1.5 M HCl in a KBr solution. Bromine addition to 2-butyne-1,4-diol was completed with more than 30 min reaction time. Additionally, blank correlation was necessary because small amounts of bromine disappeared during the reaction. It was possible to determine 2-butyne-1,4-diol in nickel plating solutions based on the findings described above. The lower limit of around 5 g m−3 was achieved. This method was not influenced by main components of the nickel-plating solution. However, the presence of allylsulfonic acid as a brightening agent elevated the quantitative values of 2-butyne-1,4-diol. Further investigation revealed that allylsulfonic acid reacts with bromine quantitatively and too rapidly. Results show that the selective determination of 2-butyne-1,4-diol and allylsulfonic acid in a nickel-plating solution became possible using different reaction times for brightening agents and bromine.
A film formed on oxygen-free copper plates immersed in 1000 ppm NaCl and 1000 ppm Na2S solutions under room temperature has been assessed qualitatively and quantitatively using cathodic reduction at a constant current density of −1 mA/cm2 in deaerated 0.1 M KCl solution. Reagent-grade purity powder specimens of cuprous oxide (Cu2O), cupric oxide (CuO), and cuprous sulfide (Cu2S) were also reduced cathodically to determine the respective reduction potentials of Cu2O, CuO, and Cu2S. The reduction potential of the film formed in 1000 ppm NaCl solution was approximately −0.8 V vs. Ag/AgCl, which is close to the reduction potential of Cu2O powder. In contrast, that of the film formed in 1000 ppm Na2S solution was approximately −1.15 V vs. Ag/AgCl, which coincided with that of Cu2S powder. Therefore, the films formed in NaCl and Na2S solutions were composed mainly of cuprous oxide and cuprous sulfide, respectively. The thickness of the film formed in NaCl solution increases logarithmically with immersion time, although the thickness of the film formed in Na2S solution increases linearly with immersion time. The film thickness, as calculated from the cathodic reduction curves, shows good agreement with data obtained using optical microscopy and EPMA analysis for the cross-sectional surface of the films.