What kind of floor am I standing on? Floor surface identification by a small humanoid robot through full-body motions

This study addresses a floor identification method for small humanoid robots that work in such daily environments as homes. The fundamental difficulty lays in a method to understand the physical properties of floors. To achieve floor identification with small humanoid robots, we used inertial sensors that can be easily installed on such robots, and dynamically selected a full-body motion that physically senses floors to achieve accurate floor identification. We collected a training data-set over 10 different kinds of common floors in home environments. We achieved 85.7% precision with our proposed method. We also demonstrate that our robot could appropriately change its locomotion behaviours depending on the floor identification results.     

Generation of high-quality higher-order Laguerre-Gaussian beams using liquid-crystal-on-silicon spatial light modulators

We report on the high-quality holographic generation of higher-order Laguerre-Gaussian (LG) beams using a liquid-crystal-on-silicon spatial light modulator. The effects of the input beam pattern on the output LG beam quality are investigated in detail through theoretical discussions and experiments. Correlation analyses between observed beam patterns and theoretical mode profiles reveal that higher beam quality is achieved for output LG beams generated from a top-hat input beam than from a Gaussian input beam.     

Cartesian-structure analysis in cast films by advanced infrared multiple-angle incidence resolution spectroscopy

Multiple-angle incidence resolution spectroscopy (MAIRS) has been improved to be an advanced algorithm so that the Cartesian structure in organic thin films can be analyzed. The infrared MAIRS technique was originally proposed as a totally new spectroscopic technique to reveal structural anisotropy in thin films on an infrared-transparent substrate, which yields both in-plane- (IP; X and Y) and out-of-plane (OP; Z)-mode spectra from an identical sample. Since this technique employs an analytical concept based on a signal decomposition of light intensity (not absorbance spectra), the algorithm intrinsically has high potential for further development. In the present study, the theoretically deduced matrix that correlates the light intensity to the angle of incidence has been modified to further decompose the IP-mode spectrum into X and Y components. As a result, anisotropic measurements of infrared spectra of thin film have become possible for the X, Y, and Z directions (Cartesian coordinate) simultaneously. With this advanced algorithm, the Cartesian structural changes in a cast film prepared on a germanium substrate have readily been analyzed, and a change from the biaxial to the uniaxial film structure with aging has spectroscopically been revealed.     

Layer-by-layer self-assembled mutilayer films of gold nanoparticles for surface-assisted laser desorption/ionization mass spectrometry

Layer-by-layer (LBL) self-assembled multilayer films of gold nanoparticles (AuNPs) on a silicon wafer were demonstrated to be promising substrates for surface-assisted laser desorption/ionization (SALDI) mass spectrometry (MS) of peptides and environmental pollutants for the first time. LBL multilayer films, (AuNPs/PAHC)n, consisting of alternating layers of ammonium citrate capped AuNPs and poly(allylamine hydrochloride) (PAHC) were prepared on a silicon surface. Silicon plates with aggregated AuNPs were more suitable than those with dispersed AuNPs for the SALDI-MS of peptides. The number of particle layers had a significant effect on the laser desorption/ionization of angiotensin I; the peak intensity of the peptide (molecular ion amount) increased with an increase in the number of layers of AuNPs. As a result, the (AuNPs/PAHC)5 multilayer films increased the sensitivity of the angiotensin I to subfemtomoles and raised the useful analyte mass range, thus making it possible to detect small proteins (a 12 kDa cytochrome c). The signal enhancement when using (AuNPs/PAHC)5 may be due to (i) the high absorption of the UV laser light at 337 nm by the AuNP layers, (ii) the low thermal conductivity due to the AuNPs being covered with a thin monolayer of PAHC, and (iii) the increase in the surface roughness (approximately 100 nm) with the number of AuNP layers. Thus, laser-induced rapid high heating of AuNPs for effective desorption/ionization of peptides is possible. In addition, it was found that (AuNPs/PAHC)5 could be used to extract environmental pollutants (pyrene and dimethyldistearylammonium chloride) from very dilute aqueous solutions with concentrations less than 10(-10) mg/mL, and the analytes trapped in the LBL film could be identified by introducing the film directly into the SALDI mass spectrometer without needing to elute the analytes out of the film.     

Surface Effects of 4He Coating on the Viscosity and the Slip Length of Normal and Superfluid 3He

We have measured the viscosity, , and the slip length, , of normal and superfluid ³ He using a torsional oscillator with a thick sample space. We coated the oscillating surface with 2.5 layers of ⁴ He film to study how the ⁴ He thin film changes the scattering mechanism of ³ He quasiparticles at the cell wall at 5 bar and 21 bar. In the normal phase, the temperature dependence of the viscosity was changed a little by the ⁴ He film at 21 bar but no change was observed at 5 bar. The slip length was enhanced by ⁴ He coating at 5 bar. This enhancement indicates the increase of specularity of ³ He quasiparticles scattering at the oscillating surface. On the other hand, a reduction of the slip length was observed at 21 bar. In the superfluid phase, the temperature dependence of supports the existence of Andreev reflection even with ⁴ He film on the surface at 5 bar and 21 bar.     

Effect of aging on microstructural development in an Al–Mg–Si alloy processed by high-pressure torsion

Experiments were conducted to evaluate the microstructural evolution in a commercial Al-0.6 % Mg-0.4 % Si alloy processed using high-pressure torsion for up to 20 turns. Disks of the alloy were tested in two different conditions: in a solution-treated condition and after a short aging treatment at 523 K. The results show that HPT processing introduces significant grain refinement through HPT processing including a reduction in grain size from ~150 μm to ~720 nm in 1 turn of HPT. The final grain size in this alloy was ~250 nm after 20 turns. Some tensile tests were conducted to evaluate the mechanical properties of the alloy at the solution treatment temperature. The results from these tests show that aging at 523 K leads to a small increase in ductility for all tensile samples with a maximum recorded elongation of ~230 %.     

Synthesis of Nanohole‐Structured Single‐Crystalline Platinum Nanosheets Using Surfactant‐Liquid‐Crystals and their Electrochemical Characterization

Nanohole‐structured single‐crystalline Pt nanosheets have been synthesized by the borohydride reduction of Na₂PtCl₆ confined to the lyotropic liquid crystals (LLCs) of polyoxyethylene (20) sorbitan monooleate (Tween 80) with or without nonaethylene‐glycol (C₁₂EO₉). The Pt nanosheets of around 4–10 nm in central thickness and up to 500 nm or above in diameter have a number of hexagonal‐shaped nanoholes ∼1.8 nm wide. High‐resolution electron microscope images of the nanosheets showed atomic fringes with a spacing of 0.22 nm indicating that the nanosheets are crystallographically continuous through the nanoholed and non‐holed areas. The inner‐angle distributions for the hexagonal nanoholes indicate that the six sides of the nanoholes are walled with each two Pt (111), Pt (1 1) and Pt (010) planes. The formation mechanism of nanoholed Pt nanosheets is discussed on the basis of structural and compositional data for the resulting solids and their precursory LLCs, with the aid of similar nanohole growth observed for a Tween 80 free but oleic acid‐incorporated system. It is also demonstrated that the nanoholed Pt nanostructures loaded on carbon exhibit fairly high electrocatalytic activity for oxygen reduction reaction and a high performance as a cathode material for polymer‐electrolyte fuel cells, along with their extremely high thermostability revealed through the effect of electron‐irradiation.     

Detection of wide-band E-M signals emitted from partial dischargeoccurring in GIS using wavelet transform

Recently, diagnostic techniques have been investigated to detect a partial discharge (PD) associated with a dielectric material defect in a high-voltage electrical apparatus. Gas insulated switchgear (GIS) is an important equipment in a substation, it is highly desirable to measure a partial discharge (PD) occurring in GIS which is a symptom of an insulation breakdown. As it is important to develop a noncontact method for detecting the insulation fault, this paper proposes a new method to detect the wide-band electromagnetic (E-M) wave emitted from PD using the Wavelet transform. The Wavelet transform provides a direct quantitative measure of spectral content, “dynamic spectrum”, in the time-frequency domain. This paper experimentally shows the “dynamic spectrum” of the wide-band E-M wave emitted from PD in the time-frequency domain. This method is shown to be useful for detecting the symptom of the insulation breakdown occurring in GIS     

A polymer optical waveguide with out-of-plane branching mirrors forsurface-normal optical interconnections

We have developed a simultaneous fabrication method using temperature control reactive ion etching (RIE) for channel optical waveguides incorporating plural out-of-plane branching mirrors made from polymer film. By using this method, the etching rate can be adjusted locally by controlling the temperature. This technology also enables the formation of trenches of various depths on the same polymer optical waveguide. We noted from scanning electron microscope (SEM) observations that simultaneous control of the mirror tilt angle and a smooth core surface could be achieved. To be specific, a heat treatment temperature of 130-135°C appears to be the optimum to maintain a rectangular cross section and to achieve a sufficiently smooth core surface for a polymethyl methacrylate (PMMA) waveguide. The measured propagation loss is small, in spite of the presence of a high-Δ waveguide (Δ=5.4%). For example, losses of 0.1, 0.3, and 0.7 dB/cm are measured at wavelengths of 650 nm, 850 nm, and 1.3 μm, respectively. From far-field pattern (FFP) measurements, we found that the mirror plane was almost rectilinear, and that the reflected light can be captured efficiently by a photodiode. In operational temperature tests, we showed that intensity fluctuations of the coupling light can be reduced to less than 1.5 dB for the temperature range between -25°C and +85°C by adopting a sandwich structure with glass plates