Extensions of Merk's method to the calculation of laminar boundary layer heat transfer from a non-isothermal surface

The Merk's method for calculating non-similar boundary layer heat transfer from an isothermal surface is extended to the case with non-isothermal surface and the reliability of the method is checked in detail. It is shown that except for some small ranges of β (pressure gradient parameter) and γ (wall temperature distribution parameter), the present method yields accurate heat transfer results. Examples of application of the present method are given for a flow around a circular cylinder and for that past a flat plate. The calculations are performed in the limits Pr→∞ and Pr→0, and the results are compared with those derived from the exact asymptotic theories for these limits.     

Mixed-valence states of 11, 1111-dialkyl- and 11, 1111-bis(methylbenzyl)biferrocenium triiodides

It was found that the packing of cations and anions influences the electronic structures of mixed-valence binuclear ferrocene derivatives. Temperature-dependence of the mixed-valence state of 1¹, 1¹¹¹-diisobutylbiferrocenium triiodide was observed in a crystalline state, whereas only a trapped-valence state was found in a dispersed state. The packing effect was also observed for a series of 1¹, 1¹¹¹-dialkyl- and 1¹, 1¹¹¹-bis(methylbenzyl)biferrocenium triiodides by means of ESR spectroscopy.     

Design of an Athermalized Hybrid Single Lens in the 3-5μm Wavelength Band

With recent advances in technology, diffractive lenses can be used for a variety of applications. In this paper, the diffractive lenses are treated on an athermal chart which is developed for refractive lenses. An athermalized hybrid single lens designed with the chart, operating in the 3-5 μm wavelength band is presented.     

Luminescence fatigue and optically detected magnetic resonance in amorphous silicon-hydrogen alloys

Fatigue of the luminescence in amorphous SiH alloys has been investigated as a function of dangling bond density and of hydrogen content at 2 K. Optically detected magnetic resonance measurements have also been carried out to elucidate the origin of the fatigue effect for those samples.     

Quantum coherence in quantum dot—Aharonov–Bohm ring hybrid systems

We investigate coherent transport through hybrid systems of quantum dots and Aharonov–Bohm (AB) rings. Strong coherence over the entire system leads to the Fano effect, which originates from the interference and the phase shift caused by the discrete states in the dots. The high controllability of the system parameters reveals that the Fano effect in mesoscopic transport can be a powerful tool for detecting the phase shift of electrons. We apply it to detect electrostatic phase modulation and the phase shift in a quantum wire with a side-coupled dot. Finally, we provide an experimental answer to the problem of “neighboring in-phase Coulomb peaks”.     

Diarrhetic shellfish toxins

As the causative agents of a new type of shellfish poisoning, named diarrhetic shellfish poisoning, okadaic acid, 35(S)-methylokadaic acid, 7-O-acyl derivatives of 35(S)-methylokadaic acid, two novel polyether lactones named pectenotoxin-1 and -2 have been isolated and had their structures determined. Three pectenotoxin analogues were also present. In addition to the previously identified Dinophysis fortii, D. acuminata was newly suggested as a source of toxins.     

Studies of molecular motions in the three phases of 1,1′,2,2′-tetrachloroferrocene by Mössbauer and1H-NMR spectroscopy

The molecular motions in the three phases of 1,1′,2,2′-tetrachloroferrocene below m.p. were studied by using⁵⁷Fe-Mossbauer and¹H FT-NMR spectroscopy. In the plastic phase at the low temperature, a rotational mode around the pseudo C₅ molecular axis was found to be activated with activation energy of 15 kJ/mol and in the higher temperature phase the rotational mode of the pseudo C₅ axis itself was found to be activated with activation energy of 23 kJ/mol in addition to the rotational mode around the pseudo C₅ axis. On the⁵⁷Fe-Mossbauer spectra, a steep decrease of the areal intensity was observed above the first transition temperature. The areal intensity in the lower plastic phase was estimated to be less than a few percent relative to that at 298 K. The results were discussed in terms of different possibilities for the movement of the molecules.     

Raman scattering from GaAs-InxGa1−xAs strained-layer superllatices

Measurements of Raman scattering were performed on GaAs-In_xGa_1?xAs strained-layer superlattices, grown by molecular beam epitaxy, with lattice periods ranging from 30 ～ 250 Å and In concentrations x, 0.22 and 0.37. Only one GaAs-like longitudinal optical phonon peak was observed in each strained-layer superlattice, in contrast to the well-known result that two peaks were observed in GaAs-Al_xGa_1?xAs superlattices. The GaAs-like phonon frequencies shifted from those of bulk GaAs to those of bulk In_xGa_1?xAs alloys as the ratio of the one-layer thickness of In_xGa_1?xAs to the lattice period increases from zero to one. We conclude that the GaAs-like phonon mode is a uniform mode of the whole strained-layer superlattice and the phonon frequency is determined by the averaged In concentration.