Carbon-supported binary PtRu electrocatalysts were prepared by coimpregnation using ethanolic solutions of Pt(NH 3 ) 2 (NO 2 ) 2 as the Pt source, various Ru sources [RuCl 3 , Ru 3 (CO) 12 , and RuNO(NO 3 ) x ], and carbon black by thermal decomposition under reducing conditions, and their structure, morphology, and electrocatalytic properties were investigated. X-ray diffraction analysis and high resolution scanning electron microscopy indicated that the use of Cl-free Ru sources, i.e., Ru 3 (CO) 12 or RuNO(NO 3 ) x , afforded highly dispersed and uniform PtRu nanoparticles. Surface area measurements conducted by electro-oxidation of preadsorbed carbon monoxide indicated that the use of Ru 3 (CO) 12 as the Ru source yielded high surface area catalysts. In terms of the surfacearea specific current density (current density normalized by the specific surface area of PtRu metal obtained from preadsorbed CO electro-oxidation measurements), the electrocatalytic activity of Pt(NH 3 ) 2 (NO 2 ) 2 -Ru 3 (CO) 12 and Pt(NH 3 ) 2 (NO 2 ) 2 -RuNO(NO 3 ) x were equal. PtRu/C electrocatalysts prepared from ethanolic solutions of Pt(NH 3 ) 2 (NO 2 ) 2 -Ru 3 (CO) 12 resulted in high mass-specific activity toward methanol oxidation, with mass-specific current density as high as 159 mA mg Ϫ1 Pt at 500 mV. The efficiency of PtRu/C electrodes is discussed based on the significance of the use of Cl-free Ru sources.

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The authors developed advanced haptic displays capable of stimulating the muscles and tendons of the forearms and tactile receptors in fingers to investigate tactile and force effects on simultaneous presentation. Display A is comprised of a master hand with two sets of tactile display with a 4-by-6 array of stimulus pins driven by micro-actuators and an articulated manipulator. Display B is comprised of an articulated manipulator and an 8-by-8 array type tactile display developed in a previous paper. A series of experiments was performed using the above A and B displays to verify the presentation capability of this display type. In Experiment I, subjects grasped virtual pegs and judged their diameters. In Experiment II, subjects tried to insert the pegs into holes. In Experiment III, the crossed-angle of a comparison texture was adjusted to bring it as close as possible to the standard texture fixed during experiments. Since diameter discrimination and insertion precision of the virtual peg were increased by tactile information, tactile-force presentation was effective for peg-in-hole for relatively large clearance. On the other hand, recognition capability for virtual texture was not enhanced compared to a mouse-mounted tactile display previously developed. While the pressure display is effective for instant of touch and peg rotation representations, rotation tactile imaging is not always effective for texture recognitions.

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The authors have developed a multi-modal display capable of stimulating muscles and tendons of the forearms and tactile receptors in fingers to investigate the effects on the presentation of tactile-haptic reality. The system comprises a master hand having two sets of tactile display with a 4-by-6 array of stimulus pins driven by micro-actuator array and an articulated manipulator. To evaluate the haptic display's presentation capability, we performed two series of experiments. In Experiment A, human subjects grasped virtual pegs and they judged their diameters. In Experiment B, the human subjects tried to insert the pegs into a hole. We evaluated the presentation capability of the display on the basis of judgement precision of the peg's diameter and variation in inclination of the peg. Since diameter discrimination and insertion precision of the virtual peg were increased by tactile information, tactile-haptics presentation was effective for the peg-in-hole in the case of relatively large clearance.

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