Anti-Reflective Coatings of Flowerlike Alumina on Various Glass Substrates by the Sol–Gel Process with the Hot Water Treatment

Anti-reflective (AR) properties of flowerlike alumina thin films with a small roughness of less than 100 nm have been studied on substrates such as soda-lime silica glass, non-alkali glass, and quartz glass. The highest AR effects were obtained on quartz glass substrate, which has the lowest refractive index of the three substrates. The reflectance of quartz glass substrates coated with flowerlike Al₂O₃ was less than 0.5% in the wavelength region from 300 to 720 nm.     

Morphology of micron‐sized,monomer‐adsorbed,crosslinked polymer particles having snowmanlike shapes prepared by the dynamic swelling method

A series of monomer‐adsorbed, crosslinked polystyrene/polydivinylbenzene composite particles having snowmanlike shapes were prepared by the dynamic swelling method that the authors had proposed in 1991. The morphology of the snowman‐shaped particles was estimated with the contact angle of the monomer phase on the polymer particle. Influences of the kind of monomers and polyvinyl alcohol colloidal stabilizer on the morphology were obviously observed and discussed from the viewpoint of thermodynamic stability. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3106–3111, 2001     

Identification of novel sesterterpenes by genome mining of phytopathogenic fungi Phoma and Colletotrichum sp.

Two homologous gene clusters for the biosynthesis of sesterterpenes betaestacins were identified from two phytopathogens, Phoma betae and Colletotrichum orbiculare. Heterologous expression of identified oxidation enzymes with previously-characterized PbTS1 (BtcA_Pb) resulted in the production of seven novel sesterterpenes. Although both strains possessed homologous enzymes, oxidation state of corresponding products were different from each other, suggesting that structural diversification of sesterterpene skeletons might be achieved by these homologous enzymes with different functions.     

Photosensitive function of encapsulated dye in carbon nanotubes

Single-wall carbon nanotubes (SWCNTs) exhibit resonant absorption localized in specific spectral regions. To expand the light spectrum that can be utilized by SWCNTs, we have encapsulated squarylium dye into SWCNTs and clarified its microscopic structure and photosensitizing function. X-ray diffraction and polarization-resolved optical absorption measurements revealed that the encapsulated dye molecules are located at an off center position inside the tubes and aligned to the nanotube axis. Efficient energy transfer from the encapsulated dye to SWCNTs was clearly observed in the photoluminescence spectra. Enhancement of transient absorption saturation in the S1 state of the semiconducting SWCNTs was detected after the photoexcitation of the encapsulated dye, which indicates that ultrafast (<190 fs) energy transfer occurred from the dye to the SWCNTs.     

Development of a Simple Adjustable Zinc Acid/Base Hybrid Catalyst for C−C and C−O Bond‐Forming and C−C Bond‐Cleavage Reactions

A newly designed zinc Lewis acid/base hybrid catalyst was developed. By adjusting the Lewis acidity of the zinc center, aldol‐type additions of 2‐picolylamine Schiff base to aldehydes proceeded smoothly to afford syn‐aldol adduct equivalents, trans‐N,O‐acetal adducts, in high yields with high selectivities. NMR experiments, including microchanneled cell for synthesis monitoring (MICCS) NMR analysis, revealed that anti‐aldol adducts were formed at the initial stage of the reactions under kinetic control, but the final products were the trans‐(syn)‐N,O‐acetal adducts that were produced through a retro‐aldol process under thermodynamic control. In the whole reaction process, the zinc catalyst played three important roles: i) promotion of the aldol process (C?C bond formation), ii) cyclization process to the N,O‐acetal product (C?O bond formation), and iii) retro‐aldol process from the anti‐aldol adduct to the syn‐aldol adduct (C?C bond cleavage and C?C bond formation).     

Fivefold symmetry in superlattices of monolayer-protected gold nanoparticles

Three-dimensional (3D) superlattices of gold nanoparticles were prepared at an air/solution interface. The surface of the gold nanoparticles used is protected by N-acetylglutathione (NAG). Morphological studies revealed that the superlattices formed fivefold symmetric structures such as pentagonal rod, decahedron, and icosahedron, which were probably developed by multiple twinning. Moreover, high-resolution surface images of the superlattices in fivefold symmetry showed excellent ordered arrangements of nanoparticles with both close-packed and non-close-packed structures.     

Synthesis and morphology control of surface functionalized nanoscale yttrium aluminum garnet particles via supercritical hydrothermal method

Organic-functionalized nanoscale yttrium aluminum garnet (YAG) particles were synthesized via a simple rapid supercritical hydrothermal method in the presence of oleylamine and oleic acid as organic surface modifiers. The presence of the organic molecules resulted in the various morphologies of the produced YAG particles, including cubic, spherical and chainlike structures. Because of their hydrophobic surface character, as-synthesized particles were dispersible in organic solvents.     

Production of submicron-sized poly(methyl methacrylate) particles by dispersion polymerization with a poly(dimethylsiloxane)-based azoinitiator in supercritical carbon dioxide

 Submicron-sized, comparatively monodisperse poly (methyl methacrylate) particles were produced by dispersion polymerization of methyl methacrylate with a poly(dimethylsiloxane)-based azoinitiator in supercritical carbon dioxide at 30 MPa for 24 h at 65 °C. The initiator operated not only as a radical initiator but also as a colloidal stabilizer, and was named an “inistab”. Received: 13 February 2001 Accepted: 20 June 2001