Can a linearly polarized light beam polarize atomic spin?

Lax et al. [Phys. Rev. 11 (1975) 1365] discovered that a light beam in vacuum is not a transverse wave but does have a longitudinal field component. We investigate atomic and molecular electric dipole transitions induced by such a light beam, in particular, linearly polarized in a transverse plane. We derive the selection rules and the transition rates for various quantization axes using the paraxial approximation up to the first order of 1/kw, where k is the wave number and w is the transverse size of the light beam. The light beam is able to yield atomic spin polarization in the direction perpendicular to both the optical axis and the transverse electric field, and its magnitude is approximately 1/kw times that generated by a circularly polarized light wave with the similar intensity.     

Classical phase space revealed by coherent light

We study the far-field characteristics of oval-resonator laser diodes made of an GaAs/Al(x)Ga(1-x)As quantum well. The resonator shapes are various oval geometries, thereby probing chaotic and mixed classical dynamics. The far-field pattern shows a pronounced fine structure that strongly depends on the cavity shape. Comparing the experimental data with ray-model simulations for a Fresnel billiard yields convincing agreement for all geometries and reveals the importance of the underlying classical phase space for the lasing characteristics.     

Performance characteristics between horizontally and vertically oriented electrodes EHD ESP for collection of low-resistive diesel particulates

The novel electrohydrodynamically-assisted electrostatic precipitator (EHD ESP) was developed to suppress particle reentrainment for collection of low resistive diesel particulates. The collection efficiency was compared between vertically and horizontally oriented electrodes of the EHD ESP using 400 cc diesel engine. The particle size dependent collection efficiency was evaluated for the particle size ranging in 20 to 5000 nm using a scanning mobility particle sizer (SMPS) and a particle counter (PC). Both horizontally and vertically oriented EHD ESP showed an excellent suppression of particle reentrainment. However, the horizontally oriented electrode EHD ESP showed significantly improved for the particle size of 300–500 nm in comparison with vertically oriented electrode EHD ESP, resulting in more than 90% collection efficiency for all particle size range. The EHD ESP has high potential especially for highly concentrated marine diesel engine emission control.     

Anhydrous Silicophosphoric Acid Glass: Thermal Properties and Proton Conductivity

Anhydrous silicophosphoric acid glass with an approximate composition of H₅Si₂P₉O₂₉ was synthesized and its thermal and proton-conducting properties were characterized. Despite exhibiting a glass transition at 192 °C, the supercooled liquid could be handled as a solid up to 280 °C owing to its high viscosity. The glass and its melt exhibited proton conduction with a proton transport number of ∼1. Although covalent O−H bonds were weakened by relatively strong hydrogen bonding, the proton conductivity (4×10⁻⁴ S cm⁻¹ at 276 °C) was considerably lower than that of phosphoric acid. The high viscosity of the melt was due to the tight cross-linking of phosphate ion chains by six-fold-coordinated Si atoms. The low proton conductivity was attributed to the trapping of positively charged proton carriers around anionic SiO₆ units (expressed as (SiO_6/2)²⁻) to compensate for the negative charges.     

Low-temperature reflection spectrum of K-TCNQ single crystal

Polarized reflection spectra of a K-TCNQ single crystal have been measured at 27,295 and 413 K. The absorption spectra were derived from the observed reflection spectra by Kramers-Kronig transformation. At 27 K, the near-infrared absorption band which is associated with the charged transfer between TCNQ^? ions, splits into a strong sharp peak at 8 × 10³ cm^?1 and a weak broad band at 11 × 10³ cm^?1. These bands were interpreted in terms of the strongly correlated extended Hubbard model including the nearest-neighbor Coulomb interaction.     

Biotransformation of benzaldehyde-type and acetophenone-type derivatives by Pharbitis nil hairy roots

The glucosylation of some coumarin and flavone derivatives on incubation with the hairy roots of morning glory (Pharbitis nil) was previously reported. We further studied the biotransformation of benzaldehyde- and acetophenone-type derivatives. Vanillin and isovanillin were reduced to alcoholic derivatives and glucosylated at the phenolic and the alcoholic hydroxyl groups. In the case of 3,4-dihydroxybenzaldehyde, the formyl group was reduced and the 3-hydroxyl or 4-hydroxyl groups were glucosylated to give monoglucosides. The 3-hydroxyl group was predominantly glucosylated to the 4-hydroxyl group. 4-beta-D-Glucopyranosyloxy-3-methoxybenzylalcohol was obtained in low yield. In time-course experiments with vanillin, it was found that the high-level reduction of the formyl group and glucosylation of the phenolic hydroxyl group occurred, and finally 4-O-beta-D-glucopyranosylvanillylalcohol was obtained as the main product. In the case of 3,4-dimethoxybenzaldehyde, 3,4,5-trimethoxybenzaldehyde, and salicylaldehyde, the formyl groups were reduced, and then the hydroxyl groups at the benyl position were glucosylated to give alcoholic glucosides in relatively high yields. In 4-hydroxy-3-methoxyacetophenone, the 4-hydroxyl group was glucosylated and two dimerized glucosides, biphenyl and biphenylether types, were obtained in low yields. In acetophenone, 1-beta-D-glucopyranosyloxy-1-phenylethane and 2-beta-D-glucopyranosyloxyacetophenone were obtained. As mentioned above P. nil hairy roots showed various biotransformative activities including glucosylation of phenolic and benzylic hydroxyl groups, reduction of the formyl group near the benzene ring, and phenol oxidation dimerization. The glucosylation reaction was especially interesting for the production of valuable glucosides.     

Synthesis of dihydroxamic acid chelating polymers and the adsorptive property for uranium in sea water

Preparation of new chelating polymers bearing dihydroxamic acid groups and the adsorptive ability for uranium in sea water are described. Chloromethylated polystyrene crosslinked with divinylbenzene was treated with diethyl malonate in N, N-dimethylformamide to give the polymer having diethyl malonate groups. This polymer was then treated with hydroxylamine in methanol to afford the dihydroxamic acid polymer. The presence of hydroxamic acid groups was confirmed by the appearance of IR absorption band at 1680 cm^?1. The dihydroxamic acid polymer contained carboxylic acid groups as well as hydroxamic acid ones, and the contents of carboxylic acid and hydroxamic acid groups were estimated from elemental analysis to be 2–3 and 2–4 mmol/g, respectively. The polymer showed the adsorptive ability of 40 μg-U/g in 8 days for uranium in sea water. In addition, the polymer showed the selective adsorptivity for iron, nickel, copper, and zinc as well as uranium. The macroreticular-type polymer showed much higher adsorption rate for uranium in sea water than the gel-type ones did, suggesting that the rate depends on the diffusion of the uranium in the polymer support.     

A Facile and Efficient Preparation of Tropone from Di-7-Cycloheptatrienyl Ether Using Trifluoroacetic Acid as a Catalyst

Tropone is prepared by an improved method in high yields without troublesome workup processes. Thus, di-7-cycloheptatrienyl ether is treated at room temperature with a small amount of trifluoroacetic acid as a catalyst.     

A study on the utilization of the Youden plot to evaluate proficiency test results

Methods of utilizing the Youden plot obtained from interlaboratory comparison tests are proposed. The Youden plot is a powerful tool for visually evaluating between- or within-laboratory errors. However, there are no generally applicable methods to indicate the anomalies in the between- and the within-laboratory errors in qualitative terms. An evaluation frame was therefore developed in this study as an indication method. Moreover, the Youden plot is considered to be useful for visually assessing the comprehensive performance of laboratories using two types of results. Although the confidence ellipse has been proposed in ISO 13528:2005 for this purpose, robust determination of the parameters has not yet been implemented. In the present study, robust determination of one of the parameters, the correlation coefficient, was developed. Our proposals were analytically validated using two types of statistical models. In addition, the properties were evaluated through computational simulations. From the results obtained, it can be concluded that our proposals are practically applicable to actual interlaboratory comparison tests.