Spectral interferometric microscope with tandem liquid-crystal Fabry-Perot interferometers for extension of the dynamic range in three-dimensional step-height measurement

The maximum measurable range of a spectral interference microscope depends on the coherence length of the light transmitted by its tunable spectral filter. To achieve a large range in step-height measurement we have developed a new tunable spectral filter that uses tandem liquid-crystal Fabry-Perot interferometers (LC-FPIs), which can simultaneously attain both a high spectral resolution and a large tuning range. Fringe visibility measurements were carried out, and it was found that the coherence length of the light transmitted through tandem LC-FPIs is two times larger than that transmitted through a single LC-FPI. Using this novel tunable spectral filter, we developed a new spectral interference microscope for the measurement of three-dimensional shapes of discontinuous objects. Experimental results of step-height measurements both with a single LC-FPI and with tandem LC-FPIs are presented for a combination of standard steel gauge block sets with 1-, 99-, and 100-microm steps. A large range (1-100 microm) of measurement with submicrometer resolution was achieved with tandem LC-FPIs that was not possible with our previous system in which a single LC-FPI was used.     

Efficient High-Pulse-Energy Green-Beam Generation by Intracavity Frequency Doubling of a Quasi-Continuous-Wave Laser-Diode-Pumped Nd:YAG Laser

A 50-mJ green beam was generated at a 1-kHz repetition rate by intracavity frequency doubling of a quasi-cw laser-diode-pumped Nd:YAG laser. The green laser was used for 12-mJ fourth-harmonic beam generation with a CsLiB(6)O(10) crystal.     

Resonance Effect on the Tunneling Reaction: H+H2→H2+H in Solid Hydrogen

The tunneling abstraction reaction: H+H₂H₂+H in -irradiated solid hydrogen has been studied using electron spin resonance (ESR) and electron-nuclear double resonance (ENDOR) spectroscopy and gas-chromatography. The rate constant for the tunneling reaction in solid hydrogen was found to decrease with the increase in the concentration of ortho-H₂ molecules in solid hydrogen. We concluded that the decrease in the rate constant is due to the energy level mismatching between reactant species of H+H₂ trapped and product species of H₂+H trapped in the reverse induced by inhomogeneous intermolecular interactions between ortho-H² molecules in solid hydrogen. This result indicates that resonance effects play an important role in tunneling reactions in solids.     

Fast agglomerative hierarchical clustering algorithm using Locality-Sensitive Hashing

The single linkage method is a fundamental agglomerative hierarchical clustering algorithm. This algorithm regards each point as a single cluster initially. In the agglomeration step, it connects a pair of clusters such that the distance between the nearest members is the shortest. This step is repeated until only one cluster remains. The single linkage method can efficiently detect clusters in arbitrary shapes. However, a drawback of this method is a large time complexity of O(n ²), where n represents the number of data points. This time complexity makes this method infeasible for large data. This paper proposes a fast approximation algorithm for the single linkage method. Our algorithm reduces the time complexity to O(nB) by rapidly finding the near clusters to be connected by Locality-Sensitive Hashing, a fast algorithm for the approximate nearest neighbor search. Here, B represents the maximum number of points going into a single hash entry and it practically diminishes to a small constant as compared to n for sufficiently large hash tables. Experimentally, we show that (1) the proposed algorithm obtains clustering results similar to those obtained by the single linkage method and (2) it runs faster for large data than the single linkage method. Hisashi Koga received the M.S. and Ph.D. degree in information science in 1995 and 2002, respectively, from the University of Tokyo. From 1995 to 2003, he worked as a researcher at Fujitsu Laboratories Ltd. Since 2003, he has been a faculty member at the University of Electro-Communications, Tokyo (Japan). Currently, he is an associate professor at the Graduate School of Information Systems, University of Electro-Communications. His research interest includes various kinds of algorithms such as clustering algorithms, on-line algorithms, and algorithms in network communications. Tetsuo Ishibashi received the M.E. degree in information systems design from the Graduate School of Information Systems at the University of Electro-Communications in 2004. Presently, he is a system engineer at Fujitsu Broad Solution & Consulting Inc. Toshinori Watanabe received the B.E. degree in aeronautical engineering in 1971 and the D.E. degree in 1985, both from the University of Tokyo. In 1971, he worked at Hitachi as a researcher in the field of information systems design. His experience includes demand forecasting, inventory and production management, VLSI design automation, knowledge-based nonlinear optimizer, and a case-based evolutionary learning system nicknamed TAMPOPO. He also engaged in FGCS (Fifth Generation Computer System) project of Japan and developed a new hierarchical message-passing parallel cooperative VLSI layout problem solver that ran on PIM (Parallel Inference Machine) in 1991. Since 1992, he has been a professor at the Graduate School of Information Systems, University of Electro-Communications, Tokyo, Japan. His areas of interest include media analysis, learning intelligence, and the semantics of information systems. He is a member of the IEEE.     

HDD seeking acoustics analysis by a transfer function approach

A new approach to analyze HDD seeking acoustics is proposed. An acoustic transfer function was derived that has seeking current as input and seeking acoustics as response. The derivation and the advantage and limitation of this acoustic transfer function approach is discussed in details in this paper. HDD seeking acoustics is mainly determined by the seeking current spectrum and the mechanical design. The acoustics transfer function represents the mechanical design, and was used to diagnose trouble mechanical modes and to guide servo design to reduce specific seeking current frequency content. The acoustic transfer function approach also enables quick performance prediction of combination of different mechanical designs and seeking currents. Various HDDs with different seeking current profiles and mechanical designs were evaluated experimentally and numerically. Finally, a new seeking servo algorithm was evaluated, and good agreement was shown between the numerical prediction using the acoustics transfer function approach and the measured seeking acoustics.     

Cermet-type hydrogen separation membrane obtained from fine particles of high temperature proton-conductive oxide and palladium

A mixed ionic and electronic conducting hydrogen separation membrane, which consisted of proton-conductive oxide and metallic palladium, was fabricated. A porous alumina tube was employed as a support, and proton-conductive oxide particles were introduced into a microporous top layer of the support by an impregnation method. Palladium particles were deposited into the same porous layer by chemical vapor deposition. Hydrogen permeated preferentially via the membrane thus obtained with a hydrogen permeance (PH₂) of 1.2 × 10^− 9 mol·m^− 2·s^− 1·Pa^− 1 at 873 K. Selectivity for hydrogen (PH₂/PN₂) increased with the operating temperature due to an increase in proton conductivity of the membrane, and PH₂/PN₂ = 5.7 was attained at 873 K.     

Real-time exploration of a multi-robot rescue system in disaster areas

A system procedure is proposed for a multi-robot rescue system that performs real-time exploration over disaster areas. Real-time exploration means that every robot exploring the area always has a communication path to human operators standing by at a base station and that the communication path is configured by ad hoc wireless networking. Real-time exploration is essential in multi-robot systems for USAR (urban search and rescue) because operators must communicate with every robot to support the victim detection process and ad hoc networking is suitable to configure a communication path among obstacles. The proposed system procedure consists of the autonomous classification of robots into search and relay types and behavior algorithms for each class of robot. Search robots explore the areas and relay robots act as relay terminals between search robots and the base station. The rule of the classification and the behavior algorithm refer to the forwarding table of each robot constructed for ad hoc networking. The table construction is based on DSDV (destination-sequenced distance vector) routing that informs each robot of its topological position in the network and other essentials. Computer simulations are executed with a specific exploration strategy of search robots. The results show that a multi-robot rescue system can perform real-time exploration with the proposed system procedure and reduce exploration time in comparison with the case where the proposed scheme is not adopted.     

Shape space estimation by higher-rank of SOM

The aim of this study is to develop an estimation method for a shape space. In this work, “shape space” means a nonlinear subspace formed by a class of visual shapes, in which the continuous change in shapes is naturally represented. By using the shape space, various operations dealing with shapes, such as identification, classification, recognition, and interpolation can be carried out in the shape space. This paper introduces an algorithm based on a generative model of shapes. A higher-rank of the self-organizing map (SOM²) is used to implement the shape space estimation method. We use this method to estimate the shape space of artificial contours. In addition, we present results from a simulation of omnidirectional camera images taken from mobile robots. Our technique accurately predicts changes in image properties as the robot’s attitude changes. Finally, we consider the addition of local features to our method. We show that the inclusion of local features solves the correspondence problem. These results suggest the potential of our technique in the future.     

Anomalous surface morphology of iron generated after anodic dissolution under magnetic fields

The effects of applied magnetic fields on the anodic dissolution of iron in a sulfuric acid solution were studied by potentiodynamic polarization measurements and electrode morphology observations. Uneven anodic dissolution occurs in the presence of magnetic field and the extent of the electrode surface inhomogeneity increases with magnetic flux density. Severely local dissolution at two edge areas of the iron electrode in the presence of magnetic fields is caused by the inhomogeneous distribution of the magnetic flux density at the ferromagnetic iron electrode and the resultant enhancement of the mass transport rate of interfacial film at local areas.