Early stages of decomposition of alloys (spinodal or nucleation)

Progress in theory and experiment on the early stage of decomposition of alloys is reviewed. In the first half of this paper, theoretical treatments on decomposition of alloys by spinodal and nucleation mechanism and also continuum theories and the discrete lattice theories are comparatively reviewed. In the latter half of this paper, experimental results on Al-Zn, Ni-Al, Cu-Co and Al-Ag alloys are discussed.     

tert-Butoxide-mediated arylation of benzene with aryl halides in the presence of a catalytic 1,10-phenanthroline derivative

Sodium tert-butoxide mediates the coupling of aryl halides with benzene derivatives without the aid of transition metal catalysts but with a catalytic 1,10-phenanthroline derivative.     

Mesostructured organosilica with a 9-mesityl-10-methylacridinium bridging unit: photoinduced charge separation in the organosilica framework

Polycondensation of 9-mesityl-10-methylacridinium-bridged organosilane in the presence of a nonionic surfactant yielded a mesostructured organosilica solid with a functional framework that exhibited long-lived photoinduced charge separation.     

Molecule-Based Artificial Photosynthesis

Guidelines for the design of molecules with a long lifetime of the charge-separated state and for the formation of a self-assembled monolayer were studied by preparing various model compounds linking donor and acceptor with chemical bonds. Based on the obtained results we designed and prepared the SAMs of C₆₀-(porphyrin)-(ferrocene)-(CH₂)₁₁SH on a gold surface and observed a photocurrent with high efficiency (25% quantum yield). In addition, a well-defined, rigid-sheet-structured oligoporphyrin with 21 porphyrin chromophores was prepared as a model for antenna chlorophylls.     

Localization and completion of nilpotent groups of automorphisms

We study nilpotent subgroups of automorphism groups in the category of groups and the homotopy category of spaces. We establish localization and completion theorems for nilpotent groups of automorphisms of nilpotent groups. We then apply these algebraic theorems to prove analogous results for certain groups of self-homotopy equivalences of spaces.     

Influence of the Grain Boundaries on the Heat Transfer in Laser Ceramics

Grain boundaries play a key role in determining several key properties of polycrystalline laser ceramics. Heat transfer measurements at low temperature constitute a good tool to probe grain boundaries. We review the results of heat transfer measurements in polycrystalline Y₃Al₅O₁₂ garnets as well as Y₂O₃ and Lu₂O₃ sesquioxide materials obtained by self-energy-driven sintering of nano-particles. The average phonon mean free path in Y₃Al₅O₁₂ was found to be significantly larger than the average grain size and to scale with temperature as T ⁻² at low temperature. Existing models describing the interaction between phonons and grain boundaries are reviewed. Correct temperature dependence of the mean free path and order of magnitude of scattering rates were found by assuming the existence of a grain boundary layer having acoustic properties different from those of the bulk. A different temperature dependence of phonon mean free path was found for the sesquioxides and was ascribed to the stronger elastic anisotropy of these materials. The thermal resistance associated to the grain boundaries of laser ceramics was found to be lower than in other dense polycrystalline ceramic materials reported in the literature.     

Labeling of Polymer Nanostructures for Medical Imaging: Importance of crosslinking extent, spacer length, and charge density

Radiolabeling studies were employed to investigate the influence of structure on the efficiency of surface functionalization for poly(acrylic acid)-coated shell crosslinked nanoparticles (SCKs) with two types of amine-terminated DOTA chelators. An intricate interplay between the chemical and physical properties of both the DOTA derivative and the SCK nanostructures was revealed, demonstrating the importance of structural control.