Theoretical Demonstration of a Newly Designed Micro-Rotator Driven by Optical Pressure on a Light Incident Surface

A newly designed cylindrical optical micro-rotator which has slopes for trapping and rotation on its upper surface is proposed. The cylindrical shape is effective in decreasing viscous drag force (damping factor) in the medium. A ray-tracing method considering the beam waist is employed to analyze the radiation pressure exerted on the upper surface of the rotator. We have demonstrated optical trapping and high speed rotation for various optical beam parameters such as the lens numerical aperture and the Gaussian mode profile as well as rotator shape parameters including oblique angle, height and diameter.     

Analog vision chip for motion detection of an approaching object against a moving background based on the insect visual system

A network for motion detection of an approaching object without influence of the moving background was proposed based on the insect visual system. The two-dimensional array of the analog complementary metal oxide semiconductor (CMOS) circuits for extracting the edge signals of the approaching object without outputting those of the moving background was inserted at the first stage of the network. At the next stage, analog CMOS circuits for detection of approaching velocity and direction, which accept the extracted edge signals, were inserted based on the locust vision system. A chip of the proposed network was fabricated with the 1.2 mm CMOS process. It was clarified from the measured results and the simulation results with the simulation program with integrated circuit emphasis (SPICE) that the two-dimensional circuits of the first stage can only generate the signals of target edges. The measured results showed that the chip can detect the approaching velocity and direction of the target in the image which contains the moving background.     

One-pot synthesis of 4-substituted 4-alkoxy-1,4-dihydro-3,1-benzoxazine-2-thiones by the reaction of 2-isothiocyanatobenzoates with organolithiums

An efficient one-pot procedure for the preparation of 4-substituted 4-alkoxy-1,4-dihydro-3,1-benzoxazine-2-thiones from 2-isothiocyanatobenzoates has been developed. Thus, 2-isothiocyanatobenzoates were reacted with organolithiums including lithium enolates of acetates and tertiary acetamides in THF at −78 °C to give the desired products in generally good yields.     

NO reduction by C3H6 over apatite-type A10(PO4)6(OH)2 (A?=?Ca and Sr)-supported Pt catalysts

A₁₀(PO₄)₆(OH)₂ (A = Ca and Sr)-supported Pt catalysts were prepared and their catalytic activity in NO reduction were investigated. The Sr₁₀(PO₄)₆(OH)₂-supported catalyst had high catalytic activity in the C₃H₆?CNO?CO₂ reaction; the activity was higher than that of the ??-Al₂O₃-supported catalyst at 300 °C. The basicity of the apatite supports would affect the chemical state of Pt on catalyst, resulting in promotion of NO reduction.     

Communication: exploring the reorientation of benzene in an ionic liquid via molecular dynamics: effect of temperature and solvent effective charge on the slow dynamics

The rotational time correlation function (RTCF) of solute benzene molecules in the ionic liquid (1-butyl-3-methylimidazolium chloride) has been studied using classical molecular dynamics simulation. The effect of solvent charge on the functional form of RTCF was investigated by comparing four force fields for the solvent where the total charge on the anion and the cation was set to ±1e, ±0.7e, ±0.5e, and 0, respectively. For all three charged solvent models, the RTCF exhibits a long-time tail where the relaxation rate exhibits a significant slowdown. This feature is strengthened by higher solvent charges as well as lower temperatures, indicating the influence of the strong Coulombic fields arising from the solvent charges. The long-time tail is caused by the extraordinarily slow solvent structural relaxation of ionic liquids compared to the time scale of their local vibrational and librational dynamics.     

Laser induced fluorescence spectroscopy of tetracene with large Ar, Ne, and H2 clusters in superfluid He nanodroplets

Clusters of tetracene molecules with different numbers of attached (Ar)(N), (Ne)(N) and (H(2))(N) particles (N = 1-2000) are assembled inside superfluid He nanodroplets and studied via laser-induced fluorescence. The frequency shift of the fluorescence spectrum of the tetracene molecules is studied as a function of cluster size and pickup order of tetracene and cluster species. For (Ar)(N) and (Ne)(N) clusters, our results indicate that the tetracene molecules reside inside the clusters when tetracene is captured by the He nanodroplet before the cluster species; conversely, the tetracene molecules stay on the surface of the clusters when tetracene is captured after the cluster species. In the case of (H(2))(N) clusters, however, tetracene molecules reside inside the (H(2))(N) clusters irrespective of the pickup order. We conclude that (Ar)(N) and (Ne)(N) clusters are rigid at T = 0.38 K, while (H(2))(N) clusters of up to N = 2000 remain fluxional at the same temperature. The results may also indicate the occurrence of heterogeneous nucleation of the (H(2))(N) clusters, which is induced by the interaction with tetracene chromophore molecules.     

Intramolecular iodoetherification of ene or diene ketals: facile synthesis of spiroketals

A novel and rapid approach to chiral mono- or di-substituted spiroketals based on remote asymmetric induction by intramolecular iodoetherification of ene or diene ketals has been developed. This strategy concisely offers 5,5- and 5,6-spiroketals including the natural insect pheromone of the wasp.