Functionalization of polymers: Epoxidation of polyolefins

In order to produce a polymer with an epoxy group, the epoxidation of the polyolefins poly(ethylene-co-1,9-decadiene) (PED) and polybutadiene (PB) was investigated. For these reactions, in situ generated peroxy acid was most effective and convenient. Among them an H₂O₂–formic acid system gave the best result. The reactivity of PB showed the dependency on the microstructure. The reactivity of the double bond is trans>cis> vinyl(pendant) and the selectivity for the epoxidation is cis∼vinyl(pendant)≫trans.     

The effect of spin multiplicity on the photochemical reaction of a 2-vinylnaphthalene-dichloromaleic anhydride system

Research on Chemical Intermediates - The photochemical reaction of a 2-vinylnaphthalene — dichloromaleic anhydride system has been studied in order to elucidate the correlation between the...     

Writing of crystal line patterns in glass by laser irradiation

We examined the laser-induced crystallization to form the fresnoite type Ba₂TiGe₂O₈ crystal line patterns in transition metal ion doped BaO–TiO₂–GeO₂ glass. Ba₂TiGe₂O₈ crystal line was written in 0.6FeO–33.3BaO–16.7TiO₂–50GeO₂ glass by continuous wave yttrium–aluminum–garnet (YAG) laser irradiation. We obtained polarization dependence of Raman spectra in crystal line pattern. Second harmonic generation (SHG) indicated unique fringe patterns from Ba₂TiGe₂O₈ crystal lines.     

Advances in quantum dots for classical and non-classical light sources Invited Paper

Recent advances in quantum dots (QDs) for classical and non-classical light sources are presented. We have established metal organic chemical vapor deposition (MOCVD) technology for InAs-based QD lasers at 1.3 μm and achieved ultralow threshold in QD lasers with photonic crystal (PhC) nanocavity. In addition, single photon emitters at 1.55/μm, GaN-based single photon sources operating at 200 K, and high-Q PhC nanocavity have been demonstrated.     

Thermal behaviour of the precursors of ruthenia-titania based mixed oxides

Summary Studies on ruthenia-titania based materials have been attractive because of their catalytic properties as well as due to the possibility of solid solution formation. Samples of pure ruthenia and ruthenia containing various amounts of titania (10-70 mol%) were investigated during heating of their hydroxide precursors from 20 to 800°C in air using emanation thermal analysis (ETA), thermogravimetry (TG), and differential thermal analysis (DTA). The resulting mixed oxide type materials were characterized by X-ray diffraction (XRD), which indicate the presence of three ruthenia-titania phases. The onset temperature of the crystallization of materials was identified by ETA results, whereas DTA effects characterized the crystallization in bulk of the samples. A good agreement was found between the ETA results and other characterization techniques used. ETA results, indicating the microstructural changes in surface and subsurface of ruthenia-titania based catalytic materials, can be used for optimization of their synthesis protocols to achieve the better physical properties.     

Electron acceleration in an ultraintense-laser-illuminated capillary

An ultraintense laser injected a 10 J of power at 1.053 microm in 0.5 ps into a glass capillary of 1 cm long and 60 microm in diameter and accelerated plasma electrons to 100 MeV. One- and two-dimensional particle codes describe wakefields with 10 GV/m gradient excited behind the laser pulse, which are guided by a plasma density channel far beyond the Rayleigh range. The blueshift of the laser spectrum supports that a plasma of 10(16) cm(-3) is inside the capillary. A bump at the high energy tail suggests the electron trapping in the wakefield.     

Synthesis of eosinophil infiltration inhibitors with antihistaminic activity

A series of [1, 2, 4]triazolo[1, 5-b]pyridazines (5) and imidazo[1, 2-b]pyridazines (6) having cyclic amines was synthesized and evaluated for antihistaminic activity and inhibitory effect on eosinophil infiltration. When a piperidine or a piperazine containing a benzhydryl group and a suitable spacer was incorporated at the 6-position, the fused pyridazines were found to exhibit both antihistaminic activity and an inhibitory effect on eosinophil chemotaxis. Above all, 6a showed potent antihistaminic activity, but little blockade of central H(1) receptors in contrast with its complete blockade of peripheral H(1) receptors as determined by an ex vivo binding assay. Furthermore, 6a inhibited eosinophil infiltration of the skin caused by a topical antigen challenge in sensitized guinea pigs, while an antihistamine terfenadine was not effective. After the pharmacokinetic study, 6a was found to be rapidly hydrolyzed to 6o, which was also orally active. Compound 6o, 2-[6-[[3-[4-(diphenylmethoxy)piperidino]propyl]amino]imidazo[1, 2-b]pyridazin-2-yl]-2-methylpropionic acid dihydrate (TAK-427), having both antihistaminic and antiinflammatory activity, is currently undergoing clinical trials as a therapeutic agent for atopic dermatitis and allergic rhinitis.     

Mössbauer study of Fe-oxide surface layers formed on small Fe particles

A Mössbauer study has been made of the iron-oxide formed on the surface of ultrafine Fe particles (about 293 Å in diameter) prepared by an aerosol method. Particular attention has been paid to the morphology of the oxide layers and to the magnetic structure. X-ray analyses indicate that the oxide layer is a mixture of Fe₃O₄ and γ-Fe₂O₃, and is composed of divided fine crystallites. Further a large non-collinearity in the spin structure of the oxide layer is found that is the likely origin of the low saturation magnetization observed for this type of system.     

Görtler vortices and boundary-layer transition

Zusammenfassung Auf Grund unserer Versuchsergebnisse sind wir zur Ansicht gekommen, dass der Einfluss der Görtler-Wirbel auf den Umschlag der Grenzschicht an konkaven Wänden mehrindirekt ist, da die Wirbel eine Veränderung der Grenzschichtdicke in der Spannweitenrichtung induzieren und die Entwicklung der instabilen Schwingungen (Tollmien-Schlichting-Wellen) modifizieren. Die Zerstörung der instabilen Schwingungen, die schliesslich zur Turbulenz führt, tritt zuerst an der Stelle auf, wo die Grenzschicht in der Querrichtung die grösste Dicke hat, und in etwas verschiedener Weise als bei den zweidimensionalen Grenzschichten an einer ebenen Platte.

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Paper prepared for dedication to ProfessorHenry Görtler on his sixtieth birthday