A miniaturization of the multi-degree-of-freedom ultrasonic actuator using a small cylinder fixed on a substrate

Multi-degree-of-freedom ultrasonic actuator has been studied for robot arms and multidimensional precision table and so on because of its simple structure, silent operation, and holding force. In this study, we aim to miniaturize multi-degree-of-freedom ultrasonic actuator for fabrication on a substrate. This actuator consists of a stainless steel cylinder and a PZT ring. The cylinder is fixed on a substrate and the PZT ring is glued to the substrate near the cylinder. The 1st longitudinal vibration and the 2nd bending vibration are simultaneously excited in the cylinder to make elliptical motion at the top of the cylinder and a ball rotor placed on the cylinder rotates because of the friction force. Length of the cylinder was decided so as to tune the resonance frequency of the 1st longitudinal vibration to the 2nd bending one. Actuator performances are evaluated experimentally using a 14 mm height and 7 mm diameter stainless steel cylinder with a 0.5 mm thickness PZT ring. The rotation about the cylinder axis is tested using the two orthogonal bending vibrations with 90 degrees phase difference. Also, the rotation about horizontal axes were investigated using the combination of the longitudinal vibration and one of two bending vibrations. We measured the rotation speed of a steel ball and obtained 15.8 rps using a 6 mm diameter ball rotor.     

Spectral Triples and the Super-Virasoro Algebra

We construct infinite dimensional spectral triples associated with representations of the super-Virasoro algebra. In particular the irreducible, unitary positive energy representation of the Ramond algebra with central charge c and minimal lowest weight h = c/24 is graded and gives rise to a net of even θ-summable spectral triples with non-zero Fredholm index. The irreducible unitary positive energy representations of the Neveu-Schwarz algebra give rise to nets of even θ-summable generalised spectral triples where there is no Dirac operator but only a superderivation.     

Enantioselective acylation of 1,2- and 1,3-diols catalyzed by aminophosphinite derivatives of (1S,2R)-1-amino-2-indanol

A phosphinite derivative that can be easily prepared in two steps from commercially available aminoindanol was found to be an effective catalyst for enantioselective acylation of diols. For the asymmetric desymmetrization of meso-1,2-diols, the corresponding monoester was obtained in up to 95% ee from the reaction in the presence of 5 mol % catalyst.     

Instability of traveling waves in an optical waveguide

Instability of traveling IR waves within a waveguide structure is discussed. A practical model of a traveling wave amplifier of a solid state is proposed, utilizing an optical waveguide. The mechanism of instability is interpreted in terms of an interaction between a plasmon wave and a circuit one under a constraining boundary condition. Properties of the traveling amplification and related problems are discussed, with appropriately suggested semiconductor materials and device designs. The features of the amplifier are a simple structure, a low DC biasing power dissipation for room-temperature operation, unidirectionality, and a wide wavelength range from IR or submillimeter order, suited to various applications.     

Palladium-catalyzed synthesis of terminal acetals via highly selective anti-Markovnikov nucleophilic attack of pinacol on vinylarenes, allyl ethers, and 1,5-dienes

A palladium-catalyzed reaction of vinylarenes, allyl ethers, and 1,5-dienes with pinacol proceeded via a selective anti-Markovnikov nucleophilic attack to afford corresponding terminal acetals as major products. The bulkiness of pinacol was found to be critical in controlling the regioselectivity.     

Application of photoactive yellow protein as a photoresponsive module for controlling hemolytic activity of staphylococcal α-hemolysin

A chimeric protein (N-PYP-Hla), consisting of staphylococcal pore-forming toxin α-hemolysin (Hla) and photoactive yellow protein (PYP), exhibited photoresponsive hemolytic activities, where visible light irradiation gave rise to retardation of hemolysis at 25 °C.     

Ion-pair chromatography of polythionates and thiosulfate with detection based on their catalytic effects on the postcolumn azide–iodine reaction

The reduction of iodine with azide, catalyzed by polythionates (tri-, tetra-, penta- and hexathionate) and thiosulfate, has been utilized as a postcolumn reaction for chromatographic determination of these sulfur oxyanions. The method is based on the separation of polythionates and thiosulfate on an octadecylsilica column with an acetonitrile–water (20:80, v/v) mobile phase (pH 5.0) containing 3 mM tetrapropylammonium hydroxide and 6 mM acetic acid, followed by photometric measurement of the residual iodine (as triiodide) from the catalytic postcolumn azide–iodine reaction after mixing a reaction solution containing azide and iodine with the column effluent. Chromatograms obtained for the sulfur oxyanions showed negative peaks as a result of the decrease in absorbance of background. The conditions for the catalytic postcolumn reaction of the sulfur oxyanions in the column effluents were established by varying the concentrations of azide, iodine, iodide and acetic acid in the reaction solution, and varying the flow-rate, reaction temperature and length of the reaction tube. The detection limits (defined as S/N=3) were 4.3 μM for trithionate, 0.10 μM for tetrathionate, 2.7 nM for pentathionate, 5.0 nM for hexathionate and 1.1 nM for thiosulfate. When compared with earlier methods, the proposed method gave a much higher sensitivity for the determination of two polythionates (penta- and hexathionate) and thiosulfate. This method was applied successfully to the analysis of polythionates and thiosulfate added to hot-spring water samples.     

Triflumizole as a Novel Lead Compound for Strigolactone Biosynthesis Inhibitor

Strigolactones (SLs) are carotenoid-derived plant hormones involved in the development of various plants. SLs also stimulate seed germination of the root parasitic plants, Striga spp. and Orobanche spp., which reduce crop yield. Therefore, regulating SL biosynthesis may lessen the damage of root parasitic plants. Biosynthetic inhibitors effectively control biological processes by targeted regulation of biologically active compounds. In addition, biosynthetic inhibitors regulate endogenous levels in developmental stage- and tissue-specific manners. To date, although some chemicals have been found as SL biosynthesis inhibitor, these are derived from only three lead chemicals. In this study, to find a novel lead chemical for SL biosynthesis inhibitor, 27 nitrogen-containing heterocyclic derivatives were screened for inhibition of SL biosynthesis. Triflumizole most effectively reduced the levels of rice SL, 4-deoxyorobanchol (4DO), in root exudates. In addition, triflumizole inhibited endogenous 4DO biosynthesis in rice roots by inhibiting the enzymatic activity of Os900, a rice enzyme that converts the SL intermediate carlactone to 4DO. A Striga germination assay revealed that triflumizole-treated rice displayed a reduced level of germination stimulation for Striga. These results identify triflumizole as a novel lead compound for inhibition of SL biosynthesis.     

Second-order risk comparison of SLSE with GLSE and MLE in a regression with serial correlation

First, the second-order bias of the estimator of the autoregressive parameter based on the ordinary least squares residuals in a linear model with serial correlation is given. Second, the second-order expansion of the risk matrix of a generalized least squares estimator with the above estimated parameter is obtained. This expansion is the same as that based on a suitable estimator of the autoregressive parameter independent of the sample. Third, it is shown that the risk matrix of the generalized least squares estimator is asymptotically equivalent to that of the maximum likelihood estimator up to the second order. Last, a sufficient condition is given for the term due to the estimation of the autoregressive parameter in this expansion to vanish under Grenander's condition for the explanatory variates.