The ordinary quivers of Hochschild extension algebras for self-injective Nakayama algebras

Let T be a Hochschild extension algebra of a finite dimensional algebra A over a field K by the standard duality A-bimodule Hom_K(A, K). In this paper, we determine the ordinary quiver of T if A is a self-injective Nakayama algebra by means of the ?-graded second Hochschild homology group HH₂(A) in the sense of Sköldberg.     

Simple analog-digital motion detection circuit and its application to mobile robot

Simple analog-digital circuits for detecting the motion direction based on the information processing of the vertebrate retina were proposed. A network constructed with an array of proposed circuits was applied to a mobile robot. A test circuit was fabricated using discrete metal oxide semiconductor (MOS) transistors on a breadboard. The measured results of the test circuit showed that the unit circuit can output a motion signal. The motion sensor for detecting the movement direction, which consists of an array of unit circuits, was connected to the microcomputer introduced in the mobile robot. It was clarified that the proposed circuits can control the mobile robot.     

Instability and mode transition analysis of a hydrogen-rich combustion in a model afterburner

Combustion instabilities were investigated experimentally for a hydrogen-rich combustion in a model afterburner installed at the end of a high-enthalpy wind tunnel. Air was supplied at 0.3 MPa and 950 K. The combustion instabilities were studied with the time-resolved measurements of a near-infrared (NIR) emission from water molecules over 780 nm using a high-speed video camera. Pressure was also measured in the combustor. The pressure and the NIR images were analyzed by data-driven approach, which include the fast Fourier transform (FFT), the wavelet transform, the dynamic mode decomposition (DMD) and the Gaussian process latent variable methods (GP-LVM). Thermoacoustic instability was observed under a rich condition, and the amplitude of the pressure oscillation was the maximum at the overall equivalence ratio of approximately 2.4 or 2.7 as a result of the FFT. The combustion dynamics were investigated in detail for an experimental run at the equivalence ratio of 2.4. A pressure spectrogram indicated a flame–vortex interaction with a Strouhal number of 0.5 (2300 Hz), thermoacoustic instability (560 Hz), and their transitions with the wavelet transform. For NIR images, the same tendency was also observed in the spectrogram of the modes obtained by the Gabor-filtered DMD, which could clearly resolve the high-order harmonic modes of the flame–vortex interaction and the thermoacoustic instability. Furthermore, NIR images were analyzed with GP-LVM to study the evolution of the combustion dynamics in a three-dimensional latent space. Recurrence plots with the Euclidean distance function were used to visualize the evolutions of the combustion dynamics. A limit cycle behavior of the flame–vortex interaction was clearly observed, whereas the limit cycle of the thermoacoustic instability showed more complicated behaviors. The transition behaviors of the instabilities were observed in the recurrence plots in detail, indicating that the flame–vortex interaction excited the fourth harmonic mode of the thermoacoustic instability, followed by the basic mode.     

Coherent Forward Scattering Spectrometer as a Wavelength Tuning Indicator for Diode Laser Atomic Absorption Spectrometry

A coherent forward scattering spectrometer was used as a wavelength tuning indicator for diode laser atomic absorption spectrometry. Atomic absorption transition of excited argon atoms at 842.46 nm was investigated. Argon atoms were excited in a glow discharge. Coherent forward scattering signal attained maximum at 0.1 T of external magnetic field and at 12 mA discharge current in 266 Pa (2 Torr) of argon. When the lasing wavelength crossed an atomic absorption line, a spike-like signal was observed. When a continuous coherent forward scattering signal was observed, the lasing wavelength was confirmed to approach within about ±3 pm from the absorption transition of argon.     

Noncommutative resolution, F-blowups and D-modules

We explain the isomorphism between the G-Hilbert scheme and the F-blowup from the noncommutative viewpoint after Van den Bergh. In doing this, we immediately and naturally arrive at the notion of D-modules. We also find, as a byproduct, a canonical way to construct a noncommutative resolution at least for a few classes of singularities in positive characteristic.     

Structural information from the interference effect of electron-capture X-rays

We observed the interference effect of electron-capture X-rays emitted by the nuclear transformations in radioisotopes. This interference is between the direct monochromatic emission from the radioactive atoms and the emission totally reflected by the substrate surface. Nanometer-level structural information about the radioactive atoms can be obtained by analyzing the measured interference fringes because the period of these fringes depends on the position of the radioactive atoms relative to the substrate surface. In this work, we used the functional protein molecules (myosin subfragment 1 (S1)) which were radioiodinated with no carrier added¹²⁵I to observe the conformational changes in aqueous solutions.     

Photoluminescence of exciton and biexciton in GaN nanocolumns

We measured photoluminescence (PL) from excitons and biexcitons in GaN nanocolumns at low temperature and found that the PL spectra of excitons depend on the nanocolumn diameter. Taking into account the polaritonic effect of the excitons, calculation of the PL spectra revealed that the dependence on diameters causes a difference of PL intensity from side surfaces of the nanocolumns. At high excitation intensities, we also observed biexciton emissions and found that the biexciton binding energies are higher than those in bulk samples. Although the mechanism for the increase in the binding energy is not clear at present, we suppose that it arises from a spatial confinement effect due to the nanocolumn morphology.     

Application of the optically stimulated luminescence (OSL) technique in space dosimetry

This paper reviews the state of the optically stimulated luminescence (OSL) technique for space dosimetry applications, focusing on the properties of carbon-doped aluminum oxide (Al₂O₃:C). New data presented include the most complete and recent values for the relative efficiency η_HCP,γ for heavy charged particles as a function of the incident radiation's linear energy transfer (LET), obtained through ground-based experiments at heavy ion accelerators. We also discuss the factors influencing the OSL efficiencies, the LET-dependent properties of Al₂O₃:C, and the experience gained from past space experiments using Al₂O₃:C. The characterization of the OSL efficiency values as a function of LET allows the use of the OSL of Al₂O₃:C in combination with plastic nuclear track detectors for personal dosimetry of astronauts, as proposed by the NCRP Report 142.     

Comprehensive analysis of short peptides in sera from patients with IgA nephropathy

We analyzed serum short peptides comprehensively to know whether they were useful to characterize IgA nephropathy (IgAN). Serum samples from 26 patients with untreated IgAN and 25 healthy donors were tested. Short peptides with molecular weights of ～7 kDa, purified from the serum samples by magnetic‐beads‐based weak cation exchange, were detected by mass spectrometry. Then the peptide peaks detected were subjected to the multivariate data analysis by SIMCA‐P+® containing principal component analysis (PCA) and orthogonal partial‐least‐squares‐discriminate analysis (OPLS‐DA). A total of 92 peptide peaks were detected in the tested serum samples. The OPLS‐DA analysis revealed that the profile of all the peptide peak intensities discriminated the IgAN group and the healthy group completely with a high R2 value (0.919) and a high Q2 value (0.861). Further, the profile of only five peptide peaks was found to discriminate the two groups. By tandem mass spectrometry and database searching, three of the five peptides which increased in the IgAN group were identified as fragments of fibrinogen alpha chain, and the two peptides which increased in the healthy group were identified as fragments of complement C3f and kininogen‐1 light chain. Taken together, the profile of the serum short peptides would be useful to discriminate IgAN and healthy conditions. Further, the five peptides may be candidate serum markers for IgAN and may be related to pathogenesis of IgA. Copyright © 2009 John Wiley & Sons, Ltd.