Zincate-type enolate for radical α-trifluoromethylation

Ketone zincate-type enolates can be applied to radical trifluoromethylation for the general synthesis of α-CF₃-ketones, cyclopentanones in particular. The addition of diethylzinc to lithium enolates is the key in the preparation of the zincate-type enolates for efficient radical trifluoromethylation.     

Polymer electrolytes plasticized with hyperbranched polymer for lithium polymer batteries

Hyperbranched polymers (HBPs) with different terminal groups and different ethylene oxide (EO) chain lengths were prepared, and the influence of the HBP structures including molecular weights and molecular weight distribution on the ionic conductivity and the mechanical property of the composite polymer electrolytes composed of poly (ethylene oxide) (PEO), HBP, BaTiO₃ as a ceramic filler, and LiN(CF₃SO₂)₂ as a lithium salt were investigated. It was found that the molecular weights of the HBP do not affect significantly the ionic conductivity, but the molecular weight distribution might affect it, and also further branching at the terminals of the HBP led to a decrease in the ionic conductivity. The HBP with longer EO chain length was effective for enhancement of the ionic conductivity in comparison with the HBP with shorter one. The increase in cross-linkable groups (acryloyl group) at the terminals of the HBP improved the tensile strength, but caused the ionic conductivity to decrease. Loosely cross-linked composite polymer electrolyte showed higher ionic conductivity and higher tensile strength than no cross-linked one. Paper presented at the Patras Conference on Solid State Ionics — Transport Properties, Patras, Greece, Sept. 14 – 18, 2004.     

Differences in the yields of polycyclic aromatic hydrocarbons by pressurized liquid extraction and the Japanese official method

To improve the extraction of polycyclic aromatic hydrocarbons (PAHs) from sediment samples, we optimized the conditions of pressurized liquid extraction (PLE). The yields increased as the extraction temperature increased from 100 to 190 degrees C, but the effect of increasing pressure (from 15 to 20 MPa) was small. Parameters of 190 degrees C and 20 MPa, near the maximum of the equipment, gave the highest yield. Under these conditions, the yields of 17 PAHs were 1.5 - 34 times those obtained by the Japanese official method (shaking and ultrasonic extraction with acetone at room temperature).     

Accurate Quantification of Polycyclic Aromatic Hydrocarbons in Environmental Samples Using Deuterium-labeled Compounds as Internal Standards

For the accurate quantification of polycyclic aromatic hydrocarbons (PAHs) in environmental samples by isotope-dilution mass spectrometry (IDMS) and gas chromatography-mass spectrometry (GC-MS), we used deuterium-labeled PAHs (D-PAHs) as internal standards for microg g(-1)-level certified reference materials and corresponding calibration solutions. Although pressurized liquid extraction (PLE) causes significant biases in the analytical results for ng g(-1)-level samples (2.4 - 15%), biases in the analytical results by PLE (190 degrees C, 20 MPa, 2 cycles) were small (<2.3%) and negligible for microg g(-1)-level samples when expanded uncertainty (coverage factor k = 2) was considered.     

Fluorescent states of exciplex and charge-transfer complexes: experimental evidence for an identical fluorescent state

The exciplex (above ≈ 170°K) and the charge-transfer (CT) complex (below ≈ 130°K) fluorescences were observed in a nonpolar solution of 9,10-dicyanoanthracene and 2-methylnaphthalene. The fluorescence maxima, lifetimes and quantum yields of the exciplex and the CT complex show continuous changes from room temperature to 77°K suggesting an identical fluorescent state of the exciplex and CT complex.     

Experimental study of a quasi-optical cavity with slotted output mirror

This paper describes an experimental study of a quasi-optical cavity to be used in qyrotrons. The cavity configuration was designed so that its output wave could pass into a quasi-optical transmission line. The test cavity was coaxially composed of a pair of annular mirrors, one of which was a curved conical mirror and the other was a plane mirror having a radial slot array for wave output. A mode excited in the cavity at 56.4 GHz was observed by detecting the radiation wave that leaked out through the slotted mirror. It was shown that the present slotted mirror served as a partially and uniformly transparent mirror to radiate the output wave with the same mode as in the cavity.     

A statistical theory of nuclear neutrino capture

A statistical theory is proposed for the calculation of the total capture cross section of a neutrino by a nucleus. Close references are made to the statistical theory of β-decay and electron capture developed by Yamada and his collaborators. As a test of the theory, we calculate the total cross section for the capture of a solar neutrino by a ³⁷Cl nucleus.