[2.2](2,6)Biphenylenophane and [2](2,6)Biphenyleno[2](2,6)naphthalenophane

Two cyclophanes, [2.2](2,6)biphenylenophane and [2](2,6)biphenyleno[2](2,6)naphthalenophane, were prepared.     

Photometric detection of cyclodextrins in liquid chromatography by using iodine generated electrochemically in-situ

A method has been developed for photometric detection of cyclodextrins (CD) in liquid chromatography using iodine (I₂) generated electrochemically in-situ. Iodide ion in the mobile phase was electrochemically oxidized to I₂ which was subsequently reacted with I^–, in an electrochemical flow cell, forming I₃^–. The absorbance of I₃^– was found to be greatly enhanced when CD were present in the mobile phase. The absorbance enhancement was caused by the change in the mole fraction of I₃^–, because of the inclusion reaction of I₃^– with CD. On the basis of this phenomenon, CD were detected by means of a photodiode-array UV–visible detector positioned downstream of the electrochemical flow cell. The signals were found to be linearly dependent on CD concentration. Because the formation constants of I₃^– with CD decrease in the order -CD>-CD>-CD, -CD was most detectable by the method. Detection limits were 1.0 mol L^–1 for -CD, 65 mol L^–1 for monoG1--CD, 100 mol L^–1 for -CD, and 200 mol L^–1 for -CD.     

New design of a radio-frequency plasma torch

A numerical model has been developed for predicting the two-dimensional flow and temperature fields in a radio-frequency (rf) plasma torch. The method employed here is based on Boulos' model with the exception of the boundary conditions for the electric and magnetic field equations. Calculations have been made for the confirmation of a new sample injection method, which is capable of completely evaporating refractory materials at high feeding rates without interfering with the stability of the plasma. In the newly designed torch, the reagent is radially injected into the hottest part of the plasma through quartz capillary tubes set symmetrically between an inductor coil. Experimental investigations have also been performed for verifying the proper function of the design. These results provide evidence that our radial injection method developed here is more effective in practical processing than the conventional axial injection methods.     

Microwave spectrum and the structure of benzoyl chloride

The microwave spectrum of benzoyl chloride was observed in the frequency range 12–18.6 GHz. Rotational constants have been obtained for the ground vibrational state, the first three excited torsional states of the COCl group, and one of the out-of-plane bending states. The residual inertial defect obtained from the ground and the torsional excited states indicates that the equilibrium conformation is planar. Ab initio MO calculations (STO-3G) showed the potential energy curve as a function of the COCl torsional angle to be rather flat around zero degrees.     

Mesogenicity of Organophosphazenes: The Effect of Phosphazene Rings and Side Groups on the Phase Transition

Cyclotriphosphazene and cyclotetraphosphazene derivatives with mesogenic 4-N-(4-alkoxyphenyl)iminomethyl)phenoxy and 4-(4'-alkoxy)biphenoxy moieties were synthesized. Schiff base moiety has higher mesomorphic stability than that in biphenyl moiety both in cyclotriphosphazene and cyclotetraphosphazene. Cyclotriphosphazenes possess higher thermal stability in the mesomorphic phase than the cyclotetraphosphazenes, suggesting the difference in the molecular structure.     

Endoscopy system for length measurement by manual pointing with an electromagnetic tracking sensor

We propose a practical and simple measurement function of three dimensional (3D) length for endoscopy based on triangulation using manually pointed correspondences. This system is a novel combination of conventional methods. 3D length information is useful for many medical purposes and the burden of manual procedures can be reduced by focusing on length. We employed a novel combination for length measurement, that is, a monocular endoscope with an electromagnetic tracking sensor. The proposed method can measure the length without any equipment for light projection and changing the current procedure of endoscopy. Our method is made more robust and reliable than the automatic correspondence techniques through the best use of the expertise of endoscopists. We developed a prototype system and evaluated its accuracy. From experimental results, we showed that the proposed method can measure the 3D length of static objects accurately as long as the measurement geometry is suitable.     

Transport property characterization of sparse CNT networks via AFM images

A simulation method for correlating the resistivity and resistance of sparse carbon nanotube (CNT) networks via atomic force microscopy images was proposed. For the demonstration, resistance values simulated by this method were compared with values obtained by directory measuring the resistance of sparse CNT networks. Results were also compared with those obtained by a thin-film approximation in which CNT networks are approximated as thin rectangles. Simulated resistance values were closer to the experimental values of the same samples than those estimated on the basis of the thin-film approximation. The use of atomic force microscopy (AFM) images enabled the implementation of inhomogeneity to numerical models, as well as one-to-one comparison between real samples and numerical models.     

Relations of electronic energies and magnetic moments of tetra-3d metal (Mn, Fe, Co and Ni) nitrides calculated using a plane-wave basis method

Geometrical optimization of tetra-3d metal nitrides (Mn₄N, Fe₄N, Co₄N, and Ni₄N) has been performed and the relations of their energies (E) and their total magnetic moments (M) are obtained by plane-wave-basis density-functional calculations without any assumption of specific spin arrangement. The E vs. M relations obtained for Fe₄N and Mn₄N have a bimodal character. The ground state of Fe₄N is a high-spin state, which would correspond to the ferromagnetic character, while that of Mn₄N is a low-spin state, which would correspond to the observed ferrimagnetic character. Lattice constants and total magnetic moments of these tetra-3d metal nitrides are almost accurately predicted. From the spin-polarized densities of states curves, Co₄N would have the largest spin polarization ratio of 0.88, which suggests Co₄N can be a candidate material for ferromagnetic electrodes for spin-injection.     

Photoassisted chemical solution deposition method for fabricating uniformly epitaxial VO2 films

Epitaxial VO₂ films were prepared on the TiO₂ (001) substrates by the excimer-laser-assisted metal–organic deposition (ELAMOD). The quality of the epitaxial films obtained by irradiation with a KrF laser was found to be affected by the film structure obtained after preheating at 500 or 300°C. When the films containing crystal domains, which were obtained by preheating at 500°C, were irradiated with the laser at room temperature under a base pressure of 250 Pa, epitaxial and polycrystalline VO₂ phases were simultaneously formed. In contrast, when the amorphous films containing organic components, which were obtained by preheating at 300°C, were irradiated with the laser at room temperature in air, a single phase of epitaxial VO₂ was formed. By using thermal simulations, we determined that the formation of the epitaxial phase was affected both by the temperature distribution within the film during the laser irradiation and by the laser intensity at the interface between the substrate and the film. The latter factor is considered to play a role in the nucleation of crystallization, causing the epitaxial phase to form preferentially compared to the polycrystalline phase in the amorphous matrix of the films. These results indicate that the ELAMOD process is effective for the fabrication of epitaxial VO₂ films at low temperature.