Optical topography: practical problems and new applications

We will briefly review the present status of optical topography and then discuss the method of improving practicality, i.e., the signal-to-noise (S/N) ratio and the spatial resolution in observations of higher-order brain functions. The optimum wavelength pair improved the S/N ratio sixfold for deoxyhemoglobin, and new configurations of light irradiation and detection positions doubled the spatial resolution. We also report on developing application fields of optical topography. This modality will bridge the gap between natural sciences, neuroscience, and pedagogy, and show actual real-time brain activity.     

Visualization of phase objects by use of a differentiation filter

For the visualization of phase objects by use of a differentiation filter, the phase variation is changed into the intensity variation by differentiation, and then the differentiated image is integrated. In the method used in practice, the differentiated image has been recorded on a film, and then integrated by use of a filter. In this paper, however, the image differentiated by means of a filter is entered into a computer using a CCD camera and then integrated. As a result, the method provides rapid on-line processing. We have performed computer simulations and a detailed analysis of the differentiation filter and also provide the experimental results of three-dimensional image visualization.     

Industry case studies in the use of immersive virtual assembly

In this paper, we report on two engineering case studies that have been conducted as part of a Virtual Assembly Technology Consortium. The objectives of the case studies were to determine if immersive virtual assembly capabilities allow industry assembly situations to be modelled and studied realistically, and to demonstrate the downstream value of the virtual assembly capabilities in areas such as ergonomics, assembly installation, process planning, installation, and serviceability. What is of special significance is that instead of modelling simplified problems or perceived representative situations, the case studies were constructed from actual assembly floor projects and situations encountered at industry member sites and with considerable participation from industry engineers and manufacturing shop floor personnel. Based on the success of the case studies, the consortium members inferred that virtual assembly methods are poised to move out of the realm of special projects and test scenarios to deployment in the actual design and manufacturing cycle. However, in order to be truly accepted in industry, there are still issues to be addressed in terms of ease of use, portability of the applications, and preparation of the models for the evaluations. Thus, the case studies added a new dimension to the exploration and understanding of how this new technology could be of practical value in industry.     

Active anion manipulation for emergence of active functions in the nanoporous crystal 12CaO·7Al<Subscript>2</Subscript>O<Subscript>3</Subscript>: a case study of abundant element strategy

This article reviews our approach to render 12CaO · 7Al₂O₃ (C12A7) electronically active using a new concept of ‘active anion manipulation’, where nanostructures embedded within the C12A7 crystal lattice are intentionally utilized to generate chemically unstable (‘water-free active’) anions. Anionic active oxygen radicals, O⁻ and O₂⁻, are formed efficiently in C12A7 cages under high oxygen activity conditions. The configuration and dynamics of O₂⁻ in cages are revealed by a combination of continuous-wave and pulsed electron paramagnetic resonance (EPR). It is demonstrated that metal-loaded C12A7 is a promising oxidation catalyst for syngas (CO + H₂) formation from methane. Furthermore, the O⁻ ion, the strongest oxidant among active oxygen species, can be extracted from the cage into an external vacuum by applying an electric field with thermal assistance, generating a high-density O⁻ beam in the order of μA cm⁻². In contrast, heat treatment of C12A7 in a hydrogen atmosphere forms H⁻ ions in the cages. The resultant C12A7:H⁻ exhibits a persistent insulator-conductor conversion upon ultraviolet-light or electron-beam irradiation. The irradiation-induced conversion mechanism is examined by first-principle theoretical calculations. Furthermore, the presence of a severely reducing environment causes the complete substitution of electrons for anions in the cages. The resulting C12A7:e⁻, which exhibits excellent stability and an electrical conductivity greater than 100 S cm⁻¹, is regarded as an ‘electride’, an ionic compound in which electrons serve as anions. The C12A7 electride exhibits a high potential for applications involving cold cathode and thermal field electron emissions due to its small work function. Electride fabrication methods suitable for large-scale production via melt processing are described. It is also demonstrated that proton or inert gas ion implantations into C12A7 thin films at elevated temperatures are effective for both H⁻ and electron doping.     

The Principles of Eliminating Pulsating Torque in Current Source Inverter Induction Motor Systems

The problem of reducing the pulsating torque in current source inverter induction motor systems is investigated. Two typical approaches presented in recent publications are analyzed by making clear 1) the correlation among the current harmonics and the torque harmonics, and 2) the conceptual contradiction existing between these two approaches. By synthesizing the analyzed results, fundamental principles for treating the current harmonics and torque harmonics are established. In addition, the method for evaluating the degree of torque ripple is described, along with a proposed criterion for torque ripple content. By applying this criterion to these two approaches, objective estimates of degree of torque pulsations, which were unfeasible so far, are now made possible.     

New DC Chopper Circuits Using Fast-Switching Reverse-Conducting Thyristors for Low-Voltage DC Motor Control

Fast- switching reverse-conducting thyristors have been developed and used in dc chopper apparatus to control the speed of highvoltage dc traction motors. The newly developed dc chopper circuit and its application for low-voltage dc motor control are discussed. The fast-switching reverse-conducting thyristor is utilized as the main thyristor to control load current.     

Organometallic Bonding in an Ullmann‐Type On‐Surface Chemical Reaction Studied by High‐Resolution Atomic Force Microscopy

The on‐surface Ullmann‐type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9‐diiododinaphtho[2,3‐b:2′,3′‐d]thiophene (I‐DNT‐VW), which is polymerized on Ag(111) in vacuum. Thermally sublimated I‐DNT‐VW picks up a Ag surface atom, forming a C? Ag bond at one end after removing an iodine. The C? Ag bond is usually short‐lived, and a C? Ag? C organometallic bond immediately forms with an adjacent molecule. The existence of the bonded Ag atoms strongly affects the bending angle and adsorption height of the molecular unit. Density functional theory calculations reveal the bending mechanism, which reveals that charge from the terminus of the molecule is transferred via the Ag atom into the organometallic bond and strengths the local adsorption to the substrate. Such deformations vanish when the Ag atoms are removed by annealing and C? C bonds are established.     

A new desk-top encounter-type haptic device with an actively driven pen-tablet LCD panel

In conventional haptic devices for virtual reality (VR) systems, a user interacts with a scene by handling a tool (such as a pen) using a mechanical device (i.e. an end-effector-type haptic device). In the case that the device can ‘mimic’ a VR object, the user can interact directly with the VR object without the mechanical constraint of a device (i.e. an encounter-type haptic device). A new challenge of an encounter-type haptic device is displaying the visuals and haptic information simultaneously on a single device. We are proposing a new desk-top encounter-type haptic device with an actively driven pen-tablet LCD panel. The proposed device is capable of providing pseudo-3D visuals and haptic information on a single device. As the result, the system provides to the user a sense of interaction with a real object. To develop a proof-of-concept prototype, a compact parallel mechanism was developed and implemented. The aim of this research is to propose a new concept in haptic research. In this paper, the concept, the prototype, and some preliminary evaluation tests with the proposed system are presented.     

Preparation method for supported metal catalysts using w/o microemulsion: Study on immobilization conditions of metal particles by hydrolysis of alkoxide

It was previously found that the silica-supported rhodium catalyst prepared using water-in-oil microemulsion had rhodium particles partly, or wholly, embedded in silica. In this work, consequently, we investigated the effect of hydrolysis conditions of tetraethylorthosilicate, employed as the source of silica, on the atomic ratio of surface rhodium in contact with the gas phase, to total surface rhodium of nanoparticles. This ratio is denoted as R in this paper. R became higher when the catalyst was prepared under the following hydrolysis conditions: a shorter hydrolysis time and a smaller amount of tetraethylorthosilicate. On the other hand, R showed the minimum value when the water content in the preparation solution was 33 vol%. From these results, it is demonstrated that it was important to form silica as early as possible in hydrolysis of TEOS in order to increase R values. In addition, the effect of R on the catalytic behavior in CO hydrogenation was investigated. At R values below 30%, the turnover frequencies increased with a decrease in R.