Synthesis of cyclodextrin‐based radial polycatenane cyclized by amide bond and subsequent fabrication of water‐soluble derivatives

Journal of Inclusion Phenomena and Macrocyclic Chemistry - In recent years, functional materials using cyclodextrin (CD)-based polyrotaxanes have attracted considerable attention, and...     

Separation and enrichment of arsenic(V) with composite resin beads containing magnetite crystals.

The adsorption of arsenic(V) was investigated using macroporous resin beads containing magnetite crystals. Arsenic(V) was favorably adsorbed at pH 2-9, where the distribution coefficients were larger than 10(3). The maximum capacity was 0.050 mmol/g. Metal cations including Ca(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and La(III) did not give serious interference at 10(-4) M level. Diluted arsenic(V) was collected with a packed column, and the retained arsenic(V) was quantitatively eluted out with 1 M NaOH.     

Up to 8-GHz Ultrafast Multi-Wavelength Routing Operation of Active Birefringent Fiber Loop Filter/Interleaver Using a Traveling-Wave-Type Phase Modulator

Ultrafast multi-wavelength routing by an active birefringent fiber loop filter/interleaver is proposed and demonstrated. In the proposed active filter, the loop part consists of a birefringent optical fiber and a traveling-wave-type phase modulator. Numerical simulation using Jones matrix analysis shows that the periodic transmission/reflection bands of the filter can be switched by changing a phase difference between clockwise and counter clockwise components passing through the birefringent fiber loop. Experimentally, we realize fast switching by controlling the applied voltage to the phase modulator, and 8-GHz wavelength routing operation is achieved.     

Study on the etching conditions of polycarbonate detectors for particle analysis of safeguards environmental samples

The fission track technique was applied to the particle analysis for safeguards environmental samples to obtain information about the isotope ratio of nuclear materials in individual particles. To detect the particles containing nuclear material with high detection efficiency and less particle loss, the influence of uranium enrichments on etching conditions of a fission track detector made of polycarbonate was investigated. It was shown that the increase in uranium enrichment shortened the suitable etching time both for particle detection and for less particle loss. From the results obtained, it was suggested that the screening of the uranium particles according to the enrichment is possible by controlling the etching time of the detector.     

Limit Theorem for Controlled Backward SDEs and Homogenization of Hamilton–Jacobi–Bellman Equations

We prove a convergence theorem for a family of value functions associated with stochastic control problems whose cost functions are defined by backward stochastic differential equations. The limit function is characterized as a viscosity solution to a fully nonlinear partial differential equation of second order. The key assumption we use in our approach is shown to be a necessary and sufficient assumption for the homogenizability of the control problem. The results generalize partially homogenization problems for Hamilton–Jacobi–Bellman equations treated recently by Alvarez and Bardi by viscosity solution methods. In contrast to their approach, we use mainly probabilistic arguments, and discuss a stochastic control interpretation for the limit equation.     

Effect of light wavelength on photooxygenation of hexamethylbenzene

Irradiation of the charge transfer complex of hexamethylbenzene with oxygen at 313 nm in a mixture of methanol and benzene afforded methoxymethylpentamethylbenzene and methoxypentamethylbenzene.     

Morphology of polytetrafluoroethylene prepared by radiation-induced emulsion polymerization

The original morphology of polytetrafluoroethylene prepared by radiation-induced emulsion polymerization was studied by electron microscopy. The morphology depends on molecular weight, which in turn depends on polymerization conditions, especially the emulsifier concentration. The molecular weight decreases with increasing emulsifier concentration. The morphology changes with molecular weight roughly as follows: fibrils below 10⁵, rods between 10⁵ and 5 × 10⁵, and granular particle above 10⁶. The crystallinity is high for all morphologies.