A novel [60]fullerene receptor with a Pd(II)-switched bisporphyrin cleft

Porphyrin dimer 1, which does not have an inside cavity and cannot interact with [60]fullerene (C60), becomes an excellent C60-acceptor with a large cavity in the presence of a Pd(II) complex.     

Palladium-catalyzed multiple arylation of thiophenes

Secondary 2-thiophenecarboxamides efficiently undergo unique triarylation accompanied by formal decarbamoylation under palladium catalysis. 3-Substituted thiophenes, especially having an electron-withdrawing group, can also be triarylated.     

Observation of the fast potential change at L-H transition by a heavy-ion-beam probe on JFT-2M

The fast potential change near the separatrix is measured directly at the L-H transition by a heavy-ion-beam probe. The potential changes with two different time scales at the L-H transition triggered by a sawtooth crash: it drops at first with the time scale of 10--100 mus just after the arrival of the heat pulse due to the sawtooth crash. Then, it decreases again at a few 100 mus after the first drop at a time scale of about 200 mus.     

Infrared femtosecond laser pulse induced permanent reduction of Eu3+ to Eu2+ in a fluorozirconate glass

We report what is believed to be the first observation of permanent photoreduction of Eu(3+) to Eu(2+) in transparent and colorless Eu(3+) -doped fluorozirconate glass at room temperature, using an infrared femtosecond laser. Difference absorption and electron-spin-resonance spectra of the glass before and after laser irradiation showed that a portion of the Eu(3+) ions in the focused part of the laser inside the glass were reduced to Eu(2+) ions after laser irradiation. It is suggested that Eu(3+) ions act as electron-trapping centers, whereas active sites in the glass matrix act as hole-trapping centers, leading to the formation of Eu(2+) ions. The observed phenomenon is inferred to be useful in the fabrication of optical memory devices with high storage density and waveguide-type micro-optical devices.     

Infrared cyclotron resonance in InSb,GaAs and Ge in very high magnetic fields

Infrared cyclotron resonance was observed in n-type InSb, GaAs and Ge in very high magnetic fields up to 1.3 MOe at room temperature using a CO₂ laser. A large shift of the cyclotron mass due to the non-parabolicity of the energy band was found in each material. The band edge masses of electrons at room temperature were evaluated to be $\text{m}{}^1\text{= 0.0127 m}$ for InSb, $\text{m}{}^1\text{= 0.065}$m for GaAs and $\text{m}{}^1{}_{\mathrm{t}}\text{= 0.086}$m for Ge. The linewidth was measured in GaAs and Ge in the high fields.     

Frequency dependent Shubnikov-De Haas oscillations in Si-MOS-FET under high magnetic fields

The quantum oscillations in the AC magnetoconductance was studied for inversion layers in Si-MOS-FETs under high magnetic fields at 1.5 K. Each peak in the Shubnikov-de Haas oscillation was found to be remarkably sharpened with increasing frequency up to 50 MHz. It was also found that the width of the gate voltage for non-conductive region (σ_xx=0) increases with increasing frequency.     

Hydrogen bond directed self-assembly of core-substituted naphthalene bisimides with melamines in solution and at the graphite interface

A series of red and blue highly fluorescent core-substituted naphthalene bisimide dyes has been synthesized and they have been investigated as supramolecular building blocks. NMR and UV-Vis titration experiments of these dyes with complementary melamines revealed the formation of triple hydrogen bonds (DAD-ADA arrays) in solution. At stoichiometric ratios, ditopic melamine receptors could dissolve otherwise insoluble bisimides by means of hydrogen bonding, even in aliphatic solvents. At the solution/graphite interface, one-dimensional chains of hydrogen bonded naphthalene bisimides and two-dimensional adlayers of ditopic melamines are formed for the pure compounds but little evidence for heterocomplexes between the two complementary building blocks could be obtained.     

Observation of nonlinear coupling between small-poloidal wave-number potential fluctuations and turbulent potential fluctuations in Ohmically heated plasmas in the JFT-2M tokamak

Two types of electrostatic modes with small-poloidal wave numbers (approximately 1 and 10-15 kHz) are observed in the edge region of Ohmically heated plasmas in the JFT-2M tokamak. The envelope of the higher frequency coherent mode is modulated at the frequency of the lower frequency mode. A bispectral analysis revealed that a significant nonlinear coupling among the two types of fluctuations and the broadband background turbulent potential fluctuations occurs inside the last closed magnetic flux surface, suggesting that a nonlinear process such as the parametric-modulational instability is involved.