Fabrication of nanoparticulate porous LaOF films through film growth and thermal decomposition of ion-modified lanthanum diacetate hydroxide

This paper first reports fabrication of macro/nanotextured rare-earth oxyfluoride films. Usage of ion-modified lanthanum diacetate hydroxide (LDAH) as self-templates was successful in producing nanoparticulate lanthanum oxyfluoride (LaOF) films. LDAH template films were deposited on glass substrates through a chemical bath deposition in solutions composed of lanthanum acetate sesquihydrate, methanol, trifluoroacetic acid, and aqueous ammonia. The LDAH films had a unique, nestlike morphology owing to a two-dimensional hexagonal crystal growth. Modification of LDAH with trifluoroacetate ions led to formation of LaOF after pyrolyzing the template films at temperatures of 400-600 degrees C in air. The resultant LaOF films had a nanoparticulate porous microstructure, maintaining the morphology of the original LDAH template films. It was also successful to incorporate Eu3+ ions into LaOF through deposition of the LDAH film in a solution containing europium acetate tetrahydrate. The characteristic photoluminescence from Eu(3+) was observed with an ultraviolet-light excitation at 273 nm, indicating that Eu3+ was homogeneously distributed in LaOF host crystals. Thus the ion-modification of LDAH was also demonstrated to be a useful method for preparing nanostructured rare-earth oxyfluoride materials havingvarious cationic compositions.     

Observation of the acceleration of a single bunch by using the induction device in the KEK proton synchrotron

A single rf bunch in the KEK proton synchrotron was accelerated with an induction acceleration method from the injection energy of 500 MeV to 5 GeV.     

Facile preparation of various heteroaromatic compounds via azatitanacyclopentadiene intermediates

Coupling of acetylene, nitrile, and a titanium reagent, Ti(O-i-Pr)(4)/2 i-PrMgCl, generated new azatitanacyclopentadienes in a highly regioselective manner. Their subsequent reaction with sulfonylacetylene afforded pyridyltitanium compounds, which, upon reaction with electrophiles, gave substituted pyridines virtually as a single isomer. When optically active nitriles were used in this reaction, chiral pyridines were obtained without loss of the enantiopurity. Alternatively, the azatitanacyclopentadiene prepared from an unsymmetrical acetylene reacted with an aldehyde or another nitrile to give furans or pyrroles having four different substituents again in a regioselective manner.     

A Robust Point Spread Function Estimation for Out-of-Focus Blurred and Noisy Images Based on a Distribution of Gradient Vectors on the Polar Plane

The estimation of the point spread function (PSF) is a very important and indispensable task for practical image restoration. Various PSF estimation algorithms have been developed, especially for the out-of-focus blur. However, a majority of them are useless in an extremely noisy environment. This paper describes a new robust PSF estimation algorithm based on a distribution of gradient vectors on the logarithmic amplitude spectrum mapped to the polar plane. The proposed algorithm can estimate the out-of-focus PSF accurately and robustly, even for an image highly corrupted by noise. The effectiveness of the proposed algorithm is verified by applying it to the PSF estimation for out-of-focus blurred and noisy images.     

Novel nonionic and cationic hydrogels prepared from N-vinylacetamide

Poly(N-vinylacetamide) (polyNVA) hydrogels were prepared by the copolymerization of N-vinylacetamide (NVA) with divinyl compounds such as methylene-bis-acrylamide, methylene-bis-NVA, and butylene-bis-NVA in a high yield. The resulting hydrogels were more stable than polyacrylamide gel and showed quite a high swelling property in a wide range of pH (1–12) and even in a 5M NaCl solution. They showed not only typical characteristics nonionic hydrogels, but also an amphiphilic property and they swelled well in some organic solvents. When the gels were partially hydrolyzed, cationic hydrogels, i.e., crosslinked poly(NVA-co-vinylamine), were collected. The resulting superabsorbent hydrogels absorbed 400 times of water. © 1993 John Wiley & Sons, Inc.     

Behavior of heavy solutes on a precolumn in on-column gas chromatography

The behavior of heavy solutes present in a sample injected on the precolumn has not been clarified in on-column injection onto gas chromatograph having a capillary column coupled to an uncoated precolumn in an oven. To investigate this point, an on-column gas chromatograph has been developed which is constructed with a heatable precolumn outside the oven. Some experiments were carried out in order to evaluate the performance. As a result, it was found that heavy solutes reach the first part of the main capillary column after the solvent has gone, resulting in sharp peaks without solvent effects. The reason why sharp peaks appear for the heavy solutes is also discussed. The cold-trapping effect has been shown to play an important role in narrowing the band width of the heavy solutes. Some of the advantages of the gas chromatograph developed are also presented.