Mutual interference coefficients obtained for 639 emission lines of 68 elements in routine analysis by ICP-AES

In our previous report [1], a practical method to obtain spectral interference coefficients and to select analytical lines in ICP-AES has been suggested.The coefficients were defined as apparent mass of the analyte corresponding to the spectral interference observed for unit mass of the interferent. In this report, data of the experimentally obtained mutual interference coefficients among 639 emission lines of 68 elements are presented. The data would be also useful for different resolution spectrometers in routine analysis, they are presented on 69 Tables as Supplementary Electronic Material. Received: 28 January 1999 / Accepted: 1 March 1999     

Micromachining of crosslinked PTFE by direct photo-etching using synchrotron radiation

Micromachining of crosslinked PTFE (polytetrafluoroethylene) using synchrotron radiation direct photo-etching method has been demonstrated. High aspect-ratio microfabrication was carried out. The etching rate of crosslinked PTFE was higher than that of non-crosslinked PTFE. Through the etching rate measurements of various samples, it was found that synchrotron radiation etching rate of crosslinked PTFE only depends on the degree of crosslinking, neither molecular weight nor crystallinity. The effect of molecular motion on etching process was discussed from temperature dependence data on etching rate. Furthermore, the surface region of synchrotron radiation irradiated sample was investigated by Fourier transform infrared spectroscopy and the experimental result showed that the modification induced by synchrotron radiation proceeded before desorption.     

Hydrodynamics and boiling phenomena of water droplets impinging on hot solid

The collision of single water droplets with a hot Inconel 625 alloy surface was investigated by a two-directional flash photography technique using two digital still cameras and three flash units. The experiments were conducted under the following conditions: the pre-impact diameters of the droplets ranged from 0.53 to 0.60 mm, the impact velocities ranged from 1.7 m/s to 4.1 m/s, and the solid surface temperatures ranged from 170 °C to 500 °C. When a droplet impacted onto the solid at a temperature of 170 °C, weak boiling was observed at the liquid/solid interface. At temperatures of 200 or 300 °C, numerous vapor bubbles were formed. Numerous secondary droplets then jetted upward from the deforming droplet due to the blowout of the vapor bubbles into the atmosphere. No secondary droplets were observed for a surface temperature of 500 °C at the low-impact Weber numbers (∼30) associated with the impact inertia of the droplets. Experiments using 2.5-mm-diameter droplets were also conducted. The dimensionless collision behaviors of large and small droplets were compared under the same Weber number conditions. At temperatures of less than or equal to 300 °C, the blowout of vapor bubbles occurred at early stages for a large droplet. At a surface temperature of 500 °C, the two dimensionless deformation behaviors of the droplets were very similar to each other.     

Conformational change of proline residues observed in swollen and shrunken phases: γ‐Ray synthesis and variable temperature circular dichroism spectra of a thermo‐responding polymer,poly(acryloyl‐Pro‐OMe)

Poly(acryloyl‐L ‐proline‐methyl ester) ( 1 ) has optically active side chain, and constitutes thermoresponsive hydrogels upon crosslinking. In this study, we have prepared uncrosslinked polymer of 1 with a 10‐kGy irradiation dose of γ‐ray. For this polymer, 1 , variable temperature circular dichroism (CD) and ¹H NMR spectra have been studied in the range of 0–30 °C. The intense CD spectrum at 0 °C suggests that the side chains in 1 have an ordered orientation. The CD intensity decreases gradually with increasing temperature. The decreased intensity of CD spectra indicates that the disordering occurs for the side‐chain orientation. The CD band shape changes discontinuously at 20 °C. In the ¹H NMR spectra, signals disappear above 20 °C. These spectral change at 20 °C indicate that the phase transition occurs at around 20 °C from swollen to shrunken phase. Even after the phase transition, the CD spectra are still changing with isochromic point at 212 nm. It appears that the side‐chain conformation is still changing from one state to the other state in the shrunken phase polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4524–4530, 2000     

Side‐chain conformational changes during the thermoshrinking process: γ‐Ray polymerization and spectroscopic study of uncrosslinked poly(methacryloyl‐Ala‐OMe)

Poly(methacryloyl‐L ‐alanine‐methyl ester) (1) has an optically active side chain and consists of thermoshrinking hydrogels upon crosslinking. We synthesized an uncrosslinked polymer of 1 by the γ‐ray polymerization method. For the prepared polymer, variable‐temperature circular dichroism (CD) and ¹H NMR spectra were studied, and we found conformational changes in the optically active side chains during the thermally induced phase transition. Intense CD spectra reveal ordered conformation in the side chain of 1 below the phase transition temperature (∼28 °C). A well‐resolved ¹H NMR spectrum of 1 at 0 °C shows that the conformational angles in the polymer side chain are fixed at low‐energy minima. With increasing temperature, the frozen side chain starts rotating vigorously and takes an unordered orientation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2671–2677, 2000     

XPS spectra of chromium monosilicides and disilicides obtained by in situ fractured clean surfaces

X-ray photoelectron spectroscopy spectra of chromium monosilicide (CrSi) and disilicide (CrSi₂) were collected from a clean surface prepared by fracturing the bulk silicide compound in a spectrometer under ultrahigh vacuum; the analytical procedure for the phase identification of the Cr–Si system was examined. A negligible binding energy shift was observed in the Cr 2p_3/2 level between elemental Cr and CrSi₂, whereas the energy of CrSi was 0.2 eV lower than that of Cr and CrSi₂. The satellite peak in the Cr 2p spectra originating from the plasmon-loss phenomena was found only for CrSi and CrSi₂. The binding energy of Si 2p shifted, reflecting the silicide phases; the energy of CrSi₂ and CrSi was 0.3 eV higher and lower, respectively, than that of elemental Si. Although a slight difference in the spectral shape was observed in the valence band region, the phase identification was considered unreliable. However, the energy shifts of Si 2p and the presence of the plasmon-loss peak in the Cr 2p spectra provide important insights into the phase identification of the Cr–Si system.     

Stereo- and Enantioselective Synthesis of Propionate-Derived Trisubstituted Alkene Motifs

We report a new method for constructing propionate-derived trisubstituted alkene motifs in a stereoselective manner. 1-Substituted 1,1-di(pinacolatoboryl)-(E)-alk-2-enes are generated in situ from 1-substituted 1,1-di(pinacolatoboryl)alk-3-enes through ruthenium(II)-catalyzed double-bond transposition. These species undergo a chiral phosphoric acid catalyzed allylation reaction of aldehydes to produce the E isomers of anti-homoallylic alcohols. On the other hand, the corresponding Z isomers of anti-homoallylic alcohols are obtained when a dimeric palladium(I) complex is employed as the catalyst for this double-bond transposition. Thus, both E and Z isomers can be synthesized from the same starting materials. A B−C(sp²) bond remaining with the allylation product undergoes the Suzuki–Miyaura cross-coupling reaction to furnish a propionate-derived trisubstituted alkene motif in a stereo-defined form. The present method to construct the motifs with (E)- and (Z)-alkenes are successfully applied to the syntheses of (+)-isotrichostatic acid, (−)-isotrichostatin RK, and (+)-trichostatic acid, respectively.     

Fabrication and characterization of C60/tetrathiafulvalene solar cells

Fabrication and characterization of C₆₀/tetrathiafulvalene solar cells was carried out. Photovoltaic properties of bulk-hetero and heterojunciotn solar cells were investigated by light-induced current vs. voltage curves and optical absorption. Transmission electron microscopy (TEM) image, X-ray and electron diffraction showed that the bulk-heterojunction film had the microstructure of C₆₀ crystal structure with TTF phase. Heat treatment of the heterojunction film with tetraethylsilane improved the photovoltaic performance, yielding a slight increase of conversion efficiency. This result would be originated in improvement of microstructure around inner interface between the both crystal phases. Mechanisms of the photovoltaic properties were discussed on the basis of the experimental results.     

Noise-robust realization of Turing-complete cellular automata by using neural networks with pattern representation

A modularly-structured neural network model is considered. Each module, which we call a ‘cell’, consists of two parts: a Hopfield neural network model and a multilayered perceptron. An array of such cells is used to simulate the Rule 110 cellular automaton with high accuracy even when all the units of neural networks are replaced by stochastic binary ones. We also find that noise not only degrades but also facilitates computation if the outputs of multilayered perceptrons are below the threshold required to update the states of the cells, which is a stochastic resonance in computation.     

Small-angle polarized neutron scattering study of spherical Fe16N2 nano-particles for magnetic recording tape

We have performed small-angle polarized neutron scattering experiments of spherical Fe₁₆N₂ nano-particles, which are potential candidate materials for high density magnetic recording tape. The results were analyzed based on a core-shell model, and we evaluated the magnetic structure of the particles. The correlation between the magnetic structure and magnetic stability of the particles were discussed in terms of high density recordings.