Selective removal of tetrahydropyranyl ethers in the presence of t-butyldimethylsilyl ethers

Dimethylaluminiun chloride has been found to cleave THP ethers selectively without any removal of t-butyldimethylsilyl ethers     

Higher Harmonic Operations of Submillimeter Wave Gyrotrons (Gyrotron FU Series)

Higher harmonic operation of gyrotrons is necessary to obtain high frequencies. Some gyrotrons included in the Gyrotron FU series developed at Fukui University have achieved operation at the third and even fourth harmonics of the electron cyclotron frequency. The output lies in the millimeter to submillimeter wavelength range and the output powers are several watts to several tens of watts. In this paper, the gyrotrons and the conditions under which they operate are described in detail.     

Extraction chromatography with macroreticular polymer beads impregnated with monothiodibenzoylmethane solution

Extraction chromatography using macroreticular ethylstyrene-divinylbenzene beads impregnated with monothiodibenzoylmethane (SBB) solution has been investigated. Of the solvents used as the stationary phase, heptan-1-ol showed the highest rate of metal extraction, and loading with 0.5 ml of the solvent per g of resin was found to be the optimum. A column packed with such loaded beads can be used for the separation of nickel(II), iron(III) and cobalt(II).     

The electronic viewpoint on the morphology of the microclusters

Although the five-fold symmetry conflicts with the crystalline long range order, it can appear in some finite systems. In order to search for such possibility in the microclusters in the small size limit and to clarify the roles of the electrons in the morphology, the electronic states are studied in the tight binding scheme. The single electron spectra coming from thes- andp-atomic orbitals are derived for three types of the 13-atom clusters; with the fcc-like configuration, the hcp-like and the icosahedral. If the transfer integral between two surface atoms is put equal to that between the central and a surface atom in the icosahedral case, this configuration has the lowest total electronic energy in many cases studied, but not always. The fact that a surface atom has larger number of neighbours in the icosahedral configuration is surely of great advantage. It, however, is not almighty in the quantum case.On leave from Department of Physics, Faculty of Science, Kyoto University, Kyoto 606, Japan. A part of this work was done there     

Stability of travelling wave solutions of the active Josephson junction transmission line

The behavior of the Josephson line, which is a type of active pulse transmission line, is governed by a partial differential equation which is similar to the sine-Gordon equation. This equation has two solitary travelling wave solutions with different propagation speeds c₁ and c₂, 0 < c₁ < c₂, and a one-parameter family of spatially periodic travelling wave solutions whose propagation speeds range over the intervals (0, c₁) and (c₂, + ∞). First we prove the existence of these solutions. Second we consider the stability of these solutions by linearized stability analysis. It is shown that the slow solitary solution is stable in the sense of linearized stability and that the fast solitary solution is unstable. It is shown also that the periodic solution with the speed c, 0 < c < c₁, is stable in the sense of linearized stability and that the periodic solution with the speed c, c₂ < c < c₄, is unstable, where c₄ is a certain point in (c₂, + ∞).