Evaluation of fine structure of tubular zeolite NaA membrane by FTIR-ATR and FIB-TEM.

A zeolite NaA (LTA) membrane supported by an alumina porous support tube for pervaporation (PV) dehydration of ethanol was characterized by transmission electron microscopy (TEM) using a focused ion beam (FIB) thin-layer specimen preparation technique and by Fourier transform infrared attenuated total reflectance method (FTIR-ATR) using a diamond prism as the waveguide. FIB-TEM clearly presented cross-section images up to about 15 microm depth from the membrane surface. FTIR-ATR monitored the Si-O asymmetric stretching vibration spectrum. The Si-O spectrum was compared with the TEM image and their relationships were discussed. By combining the two methods, we could study the thickness of surface LTA crystals, the grain boundary, the LTA/alumina interface structure and the crystallinity and density of materials inside of the alumina porous support. Consequently, fine structure changes of the LTA membrane corresponding to the hydrothermal synthesis condition could be sensitively detected.     

Modification of Spatial Coherence by Means of Low-Order Zernike-Mode Adaptive Optics

Spatial coherence of the field modified by low-order adaptive optics is analyzed to establish a theoretical basis for the recent idea of using adaptive optics as a spatial coherence modifier. In this context low-order adaptive optics has the ability to correct some of the low-order aberrations specified by Zernike polynomials. The initial field to be modified is assumed to be a spatially partially coherent one resulting from phase disturbance. It is demonstrated, as in the previous study, that low-order adaptive optics serves to enhance the spatial coherence of the resultant field and that the effect of the enhancement becomes stronger as the spatial coherence of the initially partially coherent field increases. Potential applications of low-order adaptive optics as a spatial coherence modifier are briefly discussed.     

Hydrogel‐like elastic membrane consisting of semi‐interpenetrating polymer networks based on a phosphorylcholine polymer and a segmented polyurethane

To obtain a hydrogel‐like elastic membrane, we prepared semi‐interpenetrating polymer networks (IPNs) by the radical polymerization of methacrylates such as 2‐methacryloyloxyethyl phosphorylcholine (MPC), 2‐hydroxyethylmethacrylate, and triethyleneglycol dimethacrylate diffused into segmented polyurethane (SPU) membranes swollen with a monomer mixture. The values of Young's modulus for the hydrated semi‐IPN membranes were less than that for an SPU membrane because of higher hydration, but they were much higher than that for a hydrated MPC polymer gel (non‐SPU). According to a thermal analysis, the MPC polymer influenced the segment association of SPU. The diffusion coefficient of 8‐anilino‐1‐naphthalenesulfonic acid sodium salt from the semi‐IPN membrane could be controlled with different MPC unit concentrations in the membrane, and it was about 7 × 10² times higher than that of the SPU membrane. Fibroblast cell adhesion on the semi‐IPN membrane was effectively reduced by the MPC units. We concluded that semi‐IPNs composed of the MPC polymer and SPU may be novel polymer materials possessing attractive mechanical, diffusive‐release, and nonbiofouling properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 68–75, 2003     

Two-step photoionization of cold atoms by two-color evanescent-light waves and application to atom detection with high spatial resolution

We consider a new scheme of optically ionizing atoms with 10-nm-order spatial resolution. In this method, two-color near-field lights are generated on a narrow slit illuminated by two-color evanescent lights via total-internal reflection of two-wavelength light beams. In order to illustrate the feasibility, we first obtain the ionization cross section from two-step photionization of cold Rb atoms by two-color evanescent lights on a plane surface of a prism. Then, we numerically estimate the ionization efficiency as a function of the slit width using Bethe formula. The scheme is useful for detecting ground-state atoms under less perturbation by scattered light.     

HCN laser scattering on the JIPP T-IIU tokamak

A 4-channel HCN laser scattering system has been developed and applied to the JIPP T-IIU tokamak. Main aim of this system is to study microturbulence excited in the plasma, especially in the high power ICRF heating experiment. The observed density fluctuations are in a frequency range of the electron diamagnetic drift wave and have broad frequency spectra. The main part of the wavenumber is found to satisfy the condition of . In the heating experiments, deterioration of the energy confinement time is observed, and the density fluctuation level increases with the increase of the heating power.     

Electrochiroptical systems based on biphenyl-2,2′-diyl-type dicationic dyes: strong chiroptical signals through the transmission of point chirality to axial chirality

Huge CD amplitude (A = +538) was attained by diastereomeric preference (50% de) for the title dication with two bis[4-(R)-sec-butoxyphenyl]methylium units in benzene at 23 °C. Intramolecular π-π stacking is the origin for effective transmission of point chirality to axial chirality to attain the chiroptical enhancement of 400-times. Thanks to the strong CD signaling, chiroptical changes upon electrolysis could be readily detected, thus realizing a new class of electrochiroptical response systems. Chiroptical properties could also be modified by solvent polarity.