Chiral initiator-induces self-disproportionation of enantiomers via achiral chromatography: application to enantiomer separation of racemate

We report here the theoretical design and proof of principle of the first example of a conceptually new approach for the preparation of enantiomerically pure compounds from the racemates by chiral initiator-induced Self-Disproportionation of Enantiomers (SDE) via achiral chromatography.     

New plastic optical fiber using polycarbonate core and fluorescence-doped fiber for high temperature use

This article describes the development of a plastic optical fiber composed of a polycarbonate core with a glass transition temperature of 150°C, and a cladding of newly developed poly-4-methyl penten-1, which softens at 173°C. This cladding is suitable for use at temperatures up to 130°C. The minimum optical attenuation is 0.8 dB/m at 765 nm in the near-infrared region. The cause of the attenuation of the PC-core fiber was analyzed and the intrinsic loss limit was estimated to be 0.4 dB/m at 765 nm. The fiber has excellent characteristics, including thermal stability up to 125°C, high flexibility, high strength, and self-extinguishing properties.

The polycarbonate core fiber, doped organic fluorescing materials, has also been developed for automotive uses such as light guide and illuminator. Light can be transmitted through this fiber with incident optical beam perpendicular to the fiber as well as the beam parallel to the fiber.     

Direct Synthesis of 1,4‐Diols from Alkenes by Iron‐Catalyzed Aerobic Hydration and CH Hydroxylation

Various 1,4‐diols are easily accessible from alkenes through iron‐catalyzed aerobic hydration. The reaction system consists of a user‐friendly iron phthalocyanine complex, sodium borohydride, and molecular oxygen. Furthermore, the effect of additional ligands on the iron complex was examined for a model reaction. The second hydroxy group is installed by direct C(sp³)? H oxygenation, which is based on a [1,5] hydrogen shift process of a transient alkoxy radical that is formed by formal hydration of the olefin.     

Breakdown of Born‐Oppenheimer Approximation as a Physical Mechanism for Ultrafast Hydrogen Migrations in Strong Laser Driven Molecules

We propose a physical mechanism based on breakdown of the Born‐Oppenheimer approximation to rationalize the ultrafast hydrogen migration in strong laser driven isomerization reactions. A three nuclei (proton, donor, and acceptor) model is employed to develop a three step solution scheme. The proton‐donor Coulomb repulsion is shown to be responsible for the high proton mobility. We identify a proton tunneling process and use the Keldysh‐Faisal‐Reiss theory to calculate the tunneling probability. The effect of laser parameters (intensity, frequency, polarization, and pulse duration) has been studied and found to be consistent with recent experiments.     

Efficiency improvement of optical pattern recognition in ultra-fast all-optical intensity equalizer

To cope with a larger intensity fluctuation of optical signals in optical communication networks, we have proposed and demonstrated an ultra-fast all-optical intensity equalizer based on an optical pattern recognition technique. To achieve higher transfer efficiency for this equalizer, we designed and fabricated a highly-efficient optical amplitude-phase filter using a diffractive optical element for optical pattern recognition. The fabricated amplitude-phase filter provides a diffraction efficiency of 85%, and the all-optical intensity equalizer is demonstrated to have higher transfer efficiency, when this filter is used.     

Thermodynamic investigations on shape selective separation behaviors of poly(4-vinylpyridine)-grafted silica for polycyclic aromatic hydrocarbons in both normal-phase and reversed-phase high-performance liquid chromatography

With the successful implementation of poly(4-vinylpyridine)-grafted silica prepared by grafting-from approach (GF-VP(n)) as a stationary phase for the separation of polycyclic aromatic hydrocarbons (PAHs) in normal-phase HPLC, this paper describes the chromatographic retention behaviors of PAHs with GF-VP(n) in reversed-phase HPLC. Significantly higher retention factor along with enhanced shape selectivity were observed with GF-VP(n). Thermodynamic study on the retention behaviors of PAHs with GF-VP(n) in normal-phase and reversed-phase HPLC revealed that retention of PAHs was exothermic in both phases. Furthermore, higher entropic contribution was observed in reversed-phase HPLC compared to normal-phase HPLC.     

The Navier–Stokes flow around the linearly growing steady state with bounded disturbance

The existence and uniqueness of locally-in-time solutions of the Cauchy problem to the incompressible Navier–Stokes equations is established. The initial velocity U ₀ is of the form U ₀(x) := u ₀(x)−M x, where M is a real-valued matrix and u ₀ is a bounded smooth function. Our solutions satisfy the equations in the classical sense, even though the semigroup is not analytic. If M is skew-symmetric, and u ₀ is small and a sum of trigonometric functions, then obtained solutions can be extended globally-in-time with the exponential decay in time.