High-throughput, high-damage-threshold broadband beam splitter for high-order harmonics in the extreme-ultraviolet region

We demonstrate a high-throughput and high-damage-threshold beam splitter for high-order harmonics in the soft-x-ray region that uses Si and (or) SiC plates set at Brewster's angle with respect to the pump wavelength. The beam splitters are guaranteed to have a damage threshold of at least 0.8 TW/cm2 (average power density, 0.25 W/cm2) and an attenuation rate of 10(-4)-10(-5) for a 30-fs pump pulse. The measured reflection efficiency at the 27th harmonic (29.6 nm) was 0.56 for Si and 0.45 for SiC. These beam splitters are useful not only for high harmonics but also for longitudinally pumped x-ray lasers.     

Synthesis of unnatural 1-methyl-2-quinolone derivatives

Unnatural 1-methyl-2-quinolone derivatives were synthesized by regioselective C-C bond formation. When 1-methyl-3,6,8-trinitro-2-quinolone (TNQ) was treated with enamines, nucleophilic addition readily occurred at the 4-position, and succeeding hydrolysis of enamine moiety followed by elimination of nitrous acid furnished 4-acylmethyl-1-methyl-6,8-dinitro-2-quinolones. The same products could be prepared by the reaction of TNQ with ketones in the presence of triethylamine. The present reaction enabled the introduction of various kinds of acylmethyl groups substituted with alkyl, aryl or hetaryl groups.     

Behavior of Ultrafine Particles generated from organic vapors by corona ionizers

This paper reports an experimental study on the stability, coagulation and diffusion of molecular clusters and ultrafine particles generated from organic vapors by corona ionizers. Upon leaving the ionizer, particles are made to flow within several types of vessels: depending on the specific geometry of the flow system, clusters either coagulate into large particles or are deposited on the walls. Particles larger than 4nm and molecular clusters penetrate through a wire-screen type diffusion battery, but particles in the size range between 2 and 4nm are collected. Among the organic compounds tested (aromatics, alcohols, ketones and others), only aromatic compounds appear to yield unstable clusters which grow into detectable particles (>2nm) through Brownian coagulation. The other compounds either do not undergo the gas-to-particle conversion process or are too small to be detected. Furthermore, the presence of moisture seems to be of fundamental importance in the particle generation phenomenon. The addition of alcohols to the vapor mixture inhibits particle formation.     

Synthesis of star polystyrene by radical polymerization with 1,2,4,5-tetrakis(p-tert-butylphenyl selenomethyl)benzene as a novel photoiniferter

1,2,4,5-Tetrakis(p-tert-butylphenylselenomethyl)benzene was synthesized and used as a tetrafunctional photoiniferter for the polymerization of styrene. Both the yield and the number average molecular weight () of polymers increased with reaction time and linearly increased with yield of polymer. The polymerization of styrene using this novel photoiniferter permitted formation of star-shaped polystyrene containing arylseleno groups at the chain ends, and the average degree of functionality was 3.2. Photopolymerization of styrene with end-functional star polystyrene as polymeric photoiniferter afforded polystyrene having high molecular weight.     

Ruthenium complexes carrying a disialo complex-type oligosaccharide: enzymatic synthesis and its application to a luminescent probe to detect influenza viruses

Tris-bipyridine ruthenium-complexes carrying a disialo complex-type oligosaccharide were prepared via a one-pot transglycosylation using endo-glycosidase (Endo M); they bind to type-A influenza viruses with excellent affinity (IC50 = 8.4 microM), and their luminescence intensity is strongly depressed by virus-binding.     

Moment analysis of retention equilibrium, mass transfer kinetics, and thermodynamic properties in reversed-phase liquid chromatography using phenyl bonded silica gel

Information about retention equilibrium, mass transfer kinetics, and related thermodynamic properties of chromatography using phenyldimethylsilyl (Ph)-silica gel was derived by moment analysis of pulse response peak profiles. The results for the Ph-silica gel were compared with those for octadecyldimethylsilyl (C18)-silica gel. Some parameters characterizing the chromatographic behavior of the two stationary phases were correlated with the hydrophobic surface area of sample molecules. Surface diffusion had a predominant role for intraparticle diffusion. An enthalpy-entropy compensation was established for both the retention equilibrium and surface diffusion. A linear correlation was observed between the logarithm of surface diffusion coefficient (Ds) and that of retention equilibrium constant (Ka), suggesting the establishment of a linear free energy relationship. The ratio of Ds to molecular diffusivity (Dm) decreased with increasing Ka and was correlated by a single curved line. The value of Ds was of the same order of magnitude with Dm when Ka became negligible. These results suggest the presence of a sort of correlation between surface diffusion and molecular diffusion and the restriction of the molecular mobility by surface diffusion due to the retention strength.     

Hitchin–Thorpe-Type Inequalities for Pseudo-Riemannian 4-Manifolds of Metric Signature (++−−)

It is well known that the Euler characteristic χ and the Hirzebruch index τ of a compact Einstein 4-manifold satisfy the Hitchin–Thorpe inequality χ ≥ $\tfrac{3}{2}$ ; |τ|, and that these topological invariants of a compact pseudo-Riemannian Einstein 4-manifold of metric signature (++??), with certain curvature restrictions, also satisfy a similar inequality χ ≥ $\tfrac{3}{2}$ ; |τ|, which is called the Hitchin–Thorpe-type inequality. This shows that the Euler characteristic χ is nonpositive for the indefinite case. In this paper, it is shown that for a compact pseudo-Riemannian 4-manifold of signature (++??) the Hitchin–Thorpe-type inequality holds under a weaker condition, called the diagonal Einstein condition, than the Einstein condition. Our analysis is based on the fact that the existence of a metric of signature (++??) on a 4-manifold with the structure group SO _o (2,2) is equivalent to the existence of a pair of an almost complex structure and an opposite almost complex structure on the 4-manifold, which is also equivalent to the reduction of the structure group to the maximal compact subgroup SO(2) × SO(2) of SO _o (2,2).     

Development of optical pickup for mini disc drives

In order to miniaturize optical disc drives, it is important to miniaturize and thin the optical pickup. We have developed two new optical parts: the hologram laser and the actuator. By optimizing the hologram pattern of the hologram laser, optical path length is shortened. The frequency characteristics of the actuator have been stabilized by improving the damping characteristics. Thus, we have developed a compact optical pickup for Mini Disc drives, and the pickup shows high performance when it reads out an optical disc.