On the use of high-Tc superconductors for Perot-Fabry mirrors coatings

In a very rough experiment using two MgO plates, coated with a 200 Å thick YBaCuO film to increase their reflectivity, and facing each other their YBaCuO films to make a Perot-Fabry (PF) interferometer, we have observed a 43% maximum transmission and a finesse around 33 at v=29 cm^?1, in good accordance with a new phenomenological model for YBaCuO. Much higher performances can be expected by optimizing the YBaCuO film thickness.     

Electron Microscopic Study of Heat-Treated Carbon Nanotubes

Carbon nanotubes, which were made by DC arc discharge of a graphite electrode, were heat-treated at about 250°C in intermediate vacuum of 10^-4 Torr and 10^-2 Torr. Considerable thickening of carbon nanotubes and periodic morphology like that of living organisms were observed by scanning electron microscopy.     

Organic solid photochromism by photoreduction mechanism: Thionine-reductant system

Reversible color fading of various kinds of papers coated with thionine-reductant compositions with irradiation by visible light were investigated. Water-repellent papers, when coated with aqueous compositions containing thionine, triethanolamine, and PVA, indicated the most rapid reversible color-fading (photochromism); the color-fading rate occured in decreasing order: thionine, azure C, azure B, and methylene blue. Infrared spectral changes around 1600 cm^?1 with irradiation corresponded exactly to visible spectral changes, denoting that the photoredox reaction of thionine occurs even in the solid PVA matrix.     

Colour and constitution of thiophene and thiazole azo dyes: application of CNDO/S and PPP methods

The electronic absorption spectra of a series of thiophene and thiazole azo dyes have been calculated by the CNDO/S method with inclusion of the 3d atomic orbitals on the sulphur atom and by the PPP method. The results calculated by the two methods consistently suggested that the orders of bathochromic effect of the diazo and coupling are as follows.     

A simple method for measuring wire tension in drift tubes

Measuring the tension of wires in drift tubes after construction is an important procedure because sometimes the wires get loose after soldering. The method described here uses a simple circuit for observing the change in the Lissajous pattern of a wire resonating with an external magnetic field. The vibration of the wire causes a fundamental harmonic component in the current and results in a periodic change of the Lissajous pattern. Measurement of this fundamental harmonic signal provides a precise determination of the resonance frequency and the wire tension.     

Microprocessor-Controlled DC Motor for Load-Insensitive Position Servo System

The conventional proportional P controller has been often used as the position controller of the dc servo motor. When the unknown and inaccessible load torque, such as the coulomb friction, the gravity, and so on, is imposed on the dc servo motor, this control system has the steady-and/or transient-state error.     

Nano-motion actuator with large working distance for precise track following

The nano-motion actuator (NMA) had been designed for precise track following on a spin-stand which evaluated read and write performance of a high-density magnetic recording. A required specification of the original NMA was a resonance frequency of over 5 kHz and working distance of over 10 μm. However, according as industrial researches of the perpendicular magnetic recording progress, a phenomenon that is called WATER (Wide Area Track ERasure) should be evaluated on the spin-stand. Since required working distance to evaluate the WATER reaches to over 50 μm, an X–Y stage on the spin-stand was cooperated with the NMA, as usual. However, the piggyback system which combined the X–Y stage with the NMA could not observe the WATER phenomenon continuously on a disk medium. Therefore, a new NMA which had a large working distance of over 50 μm was required. The new NMA was designed and simulated several resonance modes by using 2D or 3D of EFM analysis. The new actuator called as NMA-k501 realized the working distance of 43.3 μm and the resonance frequency of 5.33 kHz with a mechanical damper. As wide servo bandwidth was reached to 2.75 kHz to apply a PID controller, clear and sharp step responses could be showed at a 1 and a 10 nm, respectively. Furthermore, when precise positioning stability was evaluated, the NMA-k501 was positioning within 0.101 nm at 3σ.     

Human-robot communication based on a mind model

We propose a mental image directed semantic theory (MIDST) and apply it to integrated multimedia information understanding, such as cross-media operations through intermediate knowledge representation. This article describes a multiagent model of the human mind based on the MIDST and its application to human–robot communication. This work was presented in part at the 10th International Symposium on Artificial Life and Robotics, Oita, Japan, February 4–6, 2005     

Harmonicity-Based Blind Dereverberation for Single-Channel Speech Signals

The distant acquisition of acoustic signals in an enclosed space often produces reverberant artifacts due to the room impulse response. Speech dereverberation is desirable in situations where the distant acquisition of acoustic signals is involved. These situations include hands-free speech recognition, teleconferencing, and meeting recording, to name a few. This paper proposes a processing method, named Harmonicity-based dEReverBeration (HERB), to reduce the amount of reverberation in the signal picked up by a single microphone. The method makes extensive use of harmonicity, a unique characteristic of speech, in the design of a dereverberation filter. In particular, harmonicity enhancement is proposed and demonstrated as an effective way of estimating a filter that approximates an inverse filter corresponding to the room impulse response. Two specific harmonicity enhancement techniques are presented and compared; one based on an average transfer function and the other on the minimization of a mean squared error function. Prototype HERB systems are implemented by introducing several techniques to improve the accuracy of dereverberation filter estimation, including time warping analysis. Experimental results show that the proposed methods can achieve high-quality speech dereverberation, when the reverberation time is between 0.1 and 1.0 s, in terms of reverberation energy decay curves and automatic speech recognition accuracy