Eu-Doped KCl storage phosphor for erasable and rewritable optical memory utilizing photostimulated luminescence phenomenon

Intense photostimulated luminescence (PSL) with a peak at 420 nm is observed in ultraviolet (UV) Iight-irradiated europium-doped potassium chloride (KCl: Eu) crystalline phosphors. The PSL characteristics of UV-irradiated KCl: Eu phosphor for optical memory application were studied. The excitation and emission mechanisms of the 420 nm PSL, which are consistent with the results obtained, are discussed.     

Biological deodorization of dimethyl sulfide using different fabrics as the carriers of microorganisms

Biological deodorization of dimethyl sulfide (DMS) was studied using nine unwoven fabrics as the carriers of microorganisms in a laboratory-scale deodorizing system. The activated carbon fabric FN-200CF-15 was the best packing material compared with other packing materials used, on the basis of removal rate. The maximum removal rate (Vm), evaluated by using Michaelis-Menten equation, was 2.28 g-Skg-dry fab.^-1 day^-1 in this fabric biofilter. The critical load of DMS in this fabric biofilter was dependent on space velocity (SV), determined as 0.78 and 0.66 g-Skg-dry fab.^-1 at SV 100 and 150 h^-1, respectively. Strain IM1 isolated from the carbon fabric FN-200CF-15 biofilter in modified Waksman (MW) medium successfully degraded DMS as well as hydrogen sulfide (H2S), methanethiol (MT), and dimethyl disulfide (DMDS) in batch test. The DMS removal rates (g-S cell^-1h-¹) by this strain measured in batch culture and calculated in FN-200CF-15 biofilter by the cell numbers appeared in MW medium were found almost equal, indicating that strain IM1 may be the dominant microorganism in this biofilter.     

Sensitized luminescence properties of dinuclear lanthanide macrocyclic complexes bearing a benzophenone antenna

Dinuclear lanthanide (Ln=Tb³⁺ or Eu³⁺) complexes (Ln₂L2) of two octadentate macrocyclic polyaminopolycarboxylic ligands connected through a benzophenone (BP) moiety (L2) have been synthesized. Sensitized luminescence properties of Ln₂L2 in water have been studied in comparison to those of BP-conjugated mononuclear Ln complexes (LnL1). The luminescence intensity of Tb₂L2 is lower than that of TbL1 because of lower triplet quantum yield of the BP moiety. In contrast, Eu₂L2 shows higher intensity than EuL1. For both Eu complexes, energy level of triplet excited-state BP (³BP*) is only 3 kJ mol⁻¹ higher than that of ⁵D₂ excited-state of Eu³⁺. The ⁵D₂ state formed by a triplet-energy transfer (TET) from ³BP* is therefore deactivated by a back energy transfer (BET) to the ground-state BP, resulting in low luminescence intensity of EuL1. In contrast, within Eu₂L2, TET from ³BP* to ⁵D₀ state of two Eu³⁺ ions is accelerated, thus leading to higher luminescence intensity. Another notable feature of Eu₂L2 is the luminescence quantum yield independent of its concentration. In contrast, for EuL1 system, an intermolecular BET occurs from ⁵D₂ state of Eu³⁺ to the ground-state BP conjugated to another EuL1 complex, resulting in a yield decrease with the concentration increase.     

One‐Step Borylation of 1,3‐Diaryloxybenzenes Towards Efficient Materials for Organic Light‐Emitting Diodes

The development of a one‐step borylation of 1,3‐diaryloxybenzenes, yielding novel boron‐containing polycyclic aromatic compounds, is reported. The resulting boron‐containing compounds possess high singlet‐triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light‐emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one‐step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron‐fused benzo[6]helicene.     

Surface dilational moduli of polymer and blended polymer monolayers spread at air-water interfaces

Surface dilational moduli of polymer monolayers, blended polymer monolayers, and polymer particle monolayers spread at air–water interfaces are reviewed, focusing on measurements using surface pressure isotherm, surface pressure relaxation, and oscillating barrier methods. Differences between the surface dilational moduli of condensed polymer monolayers and expanded polymer monolayers are explored. Moreover, the features of the surface dilational moduli in blended polymer monolayers are discussed in terms of their miscibility.     

Selective photocatalytic oxidation of alcohols to aldehydes in water by TiO2 partially coated with WO3

Semiconductor TiO₂ particles loaded with WO₃ (WO₃/TiO₂), synthesized by impregnation of tungstic acid followed by calcination, were used for photocatalytic oxidation of alcohols in water with molecular oxygen under irradiation at λ>350 nm. The WO₃/TiO₂ catalysts promote selective oxidation of alcohols to aldehydes and show higher catalytic activity than pure TiO₂. In particular, a catalyst loading 7.6 wt % WO₃ led to higher aldehyde selectivity than previously reported photocatalytic systems. The high aldehyde selectivity arises because subsequent photocatalytic decomposition of the formed aldehyde is suppressed on the catalyst. The TiO₂ surface of the catalyst, which is active for oxidation, is partially coated by the WO₃ layer, which leads to a decrease in the amount of formed aldehyde adsorbed on the TiO₂ surface. This suppresses subsequent decomposition of the aldehyde on the TiO₂ surface and results in high aldehyde selectivity. The WO₃/TiO₂ catalyst can selectively oxidize various aromatic alcohols and is reusable without loss of catalytic activity or selectivity.     

Ultrasensitive CE for heavy metal ions using the variations in the chemical structures formed from new octadentate fluorescent probes and cationic polymers

Novel fluorescent probes have been developed for the ultratrace detection of heavy metal ions by capillary electrophoresis using laser-induced fluorescence detection. Based on a molecular design, the probes are composed of an octadentate chelating moiety, a macrocyclic DOTA (tetraazacyclododecanetetraacetic acid) and an acyclic DTPA (diethylenetriaminepentaacetic acid) frame, a spacer and a fluorophore (fluorescein). These were chosen on the basis of their ability to form kinetically inert and highly emissive complexes, and to prevent a quenching effect even with heavy and paramagnetic metal ions. Addition of a cationic polymer, polybrene, in the separation buffer provided high resolution and simultaneous detection of Ca(2+), Mg(2+), Cu(2+), Zn(2+), Ni(2+), Co(2+), Mn(2+), Cd(2+) and Pb(2+). The direct fluorescence detection of these metal ions with high sensitivity at lower ppt levels, typically 2-7 × 10(-11) M (potentially sub-ppt), was successfully achieved. While separation of anionic compounds using a counter cation ("Ion Association (IA)" mode) is typically controlled by the ion association equilibrium constants, K(ass), it was found that differences in the mobilities, μ(ep(IAC)), of the ion association complexes formed between the probe complexes and counter cations are the driving forces for separation in this new method. This suggests that each of the polybrene-probe complexes has different chemical structures among metal ions, which were able to be determined by CD spectra in this investigation. This novel separation mode was termed the "Ion Association Complex (IAC)" mode, distinct from the IA mode.     

MOF-on-MOF heteroepitaxy: perfectly oriented [Zn2(ndc)2(dabco)]n grown on [Cu2(ndc)2(dabco)]n thin films

We report the successful heteroepitaxial growth of perfectly oriented hybrid MOF thin films. By employing step-by-step liquid-phase epitaxy (LPE), [Zn(2)(ndc)(2)(dabco)](n) was grown on [Cu(2)(ndc)(2)(dabco)](n), thus demonstrating that the MOF-on-MOF deposition scheme developed for powdered microcrystalline MOF materials can also be applied in connection with LPE for MOF thin films or multilayers. The deposition was monitored by surface plasmon resonance (SPR) spectroscopy, the resulting MOF heterostructures were characterized using IR spectroscopy and different types of X-ray diffraction (XRD)-based techniques. The results suggest that the LPE method is a promising way to fabricate and grow MOF heterostructures, and also demonstrates the potential of [Cu(2)(ndc)(2)(dabco)](n) MOF thin films as substrates for the LPE-based growth of different MOFs on top.