Kationische Polymerisation von Phenylbutadien. 4. Mitt. Kationische Copolymerisation von trans-1-Phenyl-1,3-butadien mit Olefin-Monomeren

Ohne Zusammenfassung     

The effects of dehydration on the magnetic properties of K2Pt(CN)4Br0.3 · xH2O

The magnetic susceptibility and the EPR measurements on the one-dimensional conductor K₂Pt(CN)₄Br_0.3 · xH₂O were performed with special attention to the effect of the water content. The appearance of the Curie-term in the spin susceptibility is observed by the dehydration of the crystal. The Curie constant increases monotonously, according to the decrease in the water content.     

Selective thermometric titration of manganese(II) with edta

The differential thermometric titrations of mixtures of Mn(II) and Zn(II), or Mn(II) and Cd(II), and the selective thermometric titrations of Mn(II) in the presence of larger amounts of Cu(II) or Ni(II) are described. The optimal conditions for these titrations are considered based on the effective enthalpy.     

Kationische Polymerisation von Phenylbutadien. 4. Mitt. Kationische Copolymerisation von trans-1-Phenyl-1,3-butadien mit Olefin-Monomeren

Ohne Zusammenfassung     

Calculation of the external quality factor of the high power input coupler for the BEPC Ⅱ superconducting cavity

It is very important to predict the coupling between the cavity and the high power input source in the coupler design. In this paper, a time domain method is used to calculate the external quality factor Qext for the BEPC Ⅱ superconducting cavity. A comparison between simulation results and experimental results is presented. The results of simulation and measurement of Qext have a good agreement within an error of 10%.The geometry parameters related with Qext are also studied.     

Electrochemical and ferromagnetic couplings in 4,4',4' '-(1,3,5-benzenetriyl)tris(phenoxyl) radical formation

4,4',4' '-(1,3,5-Benzenetriyl)tris(2,6-di-tert-butylphenol) was prepared by the cross-coupling of 1,3,5-tribromobenzene and [4-(trimethylsiloxy)phenyl]magnesium bromide. X-ray analysis of the single crystal showed a propeller-like structure with a mean dihedral angle of 39 degrees between the hydroxyphenyl and the core benzene. The phenoxyl mono-, di-, and triradicals were generated by the electrochemical oxidation of the trianion. A stepwise radical formation was revealed by a differential pulse voltammogram, electrolytic ESR spectroscopy, and a comproportionation reaction between the radicals, which was discussed as an effect of the pi-conjugated but non-Kekulé-type coupler. The quartet and triplet ground state for the tri- and diradical, respectively, were confirmed by a SQUID measurement.     

Tapered hollow waveguide for focusing infrared laser beams

A tapered hollow waveguide that can focus a laser beam into a small beam spot is proposed for medical and dental applications. We fabricated hollow tapered optics by using a traveling torch, and the shape was formed as a precise linear taper. For a hollow taper tip with input and output diameters of 700 and 200 microm, respectively, the insertion loss is as small as 0.7 dB in a 10 mm long taper. The hollow taper optic producing a 200 microm spot withstands input energy of 100 mJ. Because a focusing lens is unnecessary at the output end, the laser beam can be introduced into a deep and narrow spot with these tapered optics.