Electrochemical reactions of surface-fluorinated petroleum coke electrodes in organic solvents

Electrochemical reactions of surface-fluorinated petroleum coke (petroleum coke heat-treated at 2800 °C: PC2800) electrodes have been investigated by cyclic voltammetry and XPS analysis. Three reduction peaks were observed at 2.31 V, 0.70-0.74 V and 0.46-0.59 V versus Li/Li⁺ in the first reduction curves of cyclic voltammograms. The peak at 2.31 V appeared only for PC2800 fluorinated at 500 °C. Two reduction peaks were also observed at 0.71 V and 0.59 V for surface-oxidized PC2800. The surface oxygen was increased through the electrode preparation process while the amount of surface fluorine was reduced by hydrolysis. The reduction peak at 2.31 V shows the reduction of fluorine bonded to basal plane of graphite, and those at 0.46-0.59 V are due to the reduction of ethylene carbonate (EC) as a solvent. The peak at 0.70-0.74 V would be also attributed to the reduction of EC on the hydrophilic sites of partly oxidized PC2800 surface.     

Control of the product ratio of CO2/(CO+CO2) and inhibition of catalyst deactivation for steam reforming of gasoline to produce hydrogen

Factors controlling the product ratio of CO₂/(CO+CO₂) and methods for inhibiting deactivation of catalyst for steam reforming of gasoline were studied. Syngas (H₂+CO) as major product was produced on Ni-Mo/Al₂O₃ and the major product on Ni-Re/Al₂O₃ was H₂ and CO₂ at the same reaction conditions. Hydrogen with a high CO₂/(CO+CO₂) ratio of about 92% was produced by coupling reaction of steam reforming and water gas shift on Ni-Re/Al₂O₃ catalyst at 805 K. The multifunctional activity of the bimetallic catalyst of Ni-Re/Al₂O₃ and the suitable reaction temperature were of crucial significance for the coupling reaction. Although no deactivation could be observed on both Ni-Mo/Al₂O₃ and Ni-Re/Al₂O₃ catalysts for steam reforming of sulfur-free fuels in about 200 h of time on stream, the activity and sulfur-tolerance of Ni-Re/Al₂O₃ was much better than the values of Ni-Mo/Al₂O₃ for steam reforming of sulfur-containing fuels because of the unique role of rhenium in the Ni-Re catalyst. The unique role of rhenium in Ni-Re catalyst was mainly because of alloying of rhenium with nickel to form bimetallic Ni-Re sites and interaction of rhenium with sulfur to form S-Re binds. The sulfur-tolerance of Ni-Re/Al₂O₃ for steam reforming of sulfur-containing gasoline was improved further by addition of a small amount of ZSM-5. The activity and sulfur-tolerance of Ni-Mo/Al₂O₃ was also enhanced by the addition of ZSM-5.     

Optimizing servo-signal design for a hard-disk drives

To improve the non-repeatable runout (NRRO), repeatable runout (RRO), and nonlinearity of the position signal in hard-disk drives (HDDs), we established criteria for the off-track direction and for the bit direction. Position-signal nonlinearity and NRRO degradation are largely due to the interaction between track width, erase band size, and the sensitivity distribution of the head. So one criterion is for position-signal sensitivity. The other criterion is for burst-bit density, which causes RRO degradation. Using these criteria to compare, theoretically and experimentally, the effectiveness with which the quality of the position signal could be maintained using amplitude and phase patterns confirmed that the phase pattern is superior to the amplitude pattern.     

Advanced material processing with nano- and femto-second pulsed laser

In order to apply laser processing to advanced material mold making, basic research is carried out. First, box-shaped hole processing is carried out by laser beam scanning. Second, suitable machining conditions are investigated in terms of laser spot size, scanning path, scanning speed and scan times. Finally, the comparison of nano- with femto-second laser-processed surfaces is carried out. The laser-processed surfaces and debris are observed with a scanning electron microscope (SEM) and a laser microscope, and are also analyzed using an electron probe microanalysis (EPMA), an X-ray diffractometer and a Vickers hardness tester.     

A design based on final-state control for residual vibrationless seeking in hard disk drives

A new design method - based on a final-state control (FSC) - for short-span seeking in a hard-disk drive (HDD) has been developed. The short-span seeking is performed by two-degree-of-freedom (2-DOF) control, which uses a feedforward (FF) control input along with a reference trajectory. The design method can directly generate the FF control input, whose derivative at a specified order is minimized and whose power spectrum amplitude is reduced at a specified frequency. The residual vibration caused by mechanical resonance can therefore be reduced by the generated FF control input. Test with a 2.5-in form-factor HDD experimentally confirmed that the developed seeking control significantly reduces the residual vibration in a HDD.     

Charge Transfer in Fullerene-Conducting Polymer Compositex: Electronic and Excitonic Properties

C₆₀ doping into conducting polymer with highly extended π-electron system in the main chain induces remarkable quenching of photoluminescence in conducting polymer and drastic enhancement of photoconductivity. These results can be explained in terms of photo-induced charge transfer between conducting polymer and C₆₀. That is, photoexcited excitons or exciton-polarons on conducting polymer are effectively dissociated at C₆₀ molecules transferring electrons to C₆₀. Photoexcitation of C₆₀ results in the transfer of hole from C₆₀ to conducting polymer. These novel C₆₀ doping effects have been observed not only in conducting polymers with non-degenerated ground state structures but also those with degenerated ground state structure such as di-substituted acetylene polymers with solitonic electronic systems.

Highly effective photo-induced charge transfer has been also observed in conducting polymer/C₆₀ heterojunctions, which are interpreted as donor (D)-acceptor (A) photocell. Based on this finding we have demonstrated an organic photovoltaic cell with D-A double heterojunction, Al/C₆₀/OEP/conducting polymer/TTO, in which OEP is octaethylporphine as an light absorbing antenna molecule. Novel characteristics have also been observed in various other junction devices utilizing C₆₀ doped conducting polymer.

Granular and multiphase superconductivity has been found in C₆₀-conducting polymer-alkali metal composites.

Effect of other type of fullerenes such as C₇₀, modified C₆₀ and C₆₀ polymers, and also effect of C₆₀ doping in polysilanes and their derivatives have also been studied.     

Two methods for calculating the amount of refrigerant required for cyclic temperature testing of insulated packages

This paper describes two calculation methods for estimating the amount of refrigerant required to maintain the temperature inside a small insulating container within a desired range under cyclic temperature conditions. The first calculation method is for a phase change material (PCM) that absorbs and releases heat by melting and solidifying. The PCM used in this study had a phase change temperature of 23.5°C (74.3°F). An equation for estimating the amount of the PCM required under cyclic conditions is shown. Test packages were constructed to meet USP Controlled Room Temperature (CRT) requirements. Several cyclic tests were conducted with the calculated amount of PCM in the test packages. The results showed that the calculated amount of PCM did maintain the inside temperature within the range 21.4–25.8°C (70.5–78.4°F) throughout the tests. This range met the USP CRT requirement. The second calculation method is for unfrozen gel packs that absorb and release heat by changing temperature. The amount of unfrozen gel pack required to maintain temperature within the USP range was calculated. Several cyclic tests were conducted with the calculated amount of gel packs. The calculated amount was enough to meet the USP requirement. Good agreement between the experimental and calculated temperature profiles was also found. Copyright © 2006 John Wiley & Sons, Ltd.