Control of dispersion state of silsesquioxane nanofillers for stabilization of polystyrene thin films

The influence of the dispersion states of the nanofillers on the dewetting behavior of the polymer thin film was investigated. Polyhedral oligomeric silsesquioxanes (POSS) with various substituents were added into polystyrene (PS) thin films as the nanofillers. The dewetting rate of the films drastically changed with the surface substituents of POSS additives. Neutron reflectivity measurements indicated that the difference of the dewetting rate was associated with the dispersion state of POSS additives in the films. POSS with phenethyl groups (PhPOSS), which homogeneously dispersed into the films, resulted in the decrease of the glass transition temperature of PS and the enhancement of the dewetting of the films. POSS with a fluoroalkyl group (CpPOSS-R f) segregated to the film surface and showed the retardation of the dewetting by the decrease of the surface energy of the film. POSS with hydroxyl groups (CpPOSS-2OH) segregated to the film surface and film-substrate interface and led to the elimination of the dewetting, suggesting the importance of the interfacial segregation for the inhibition of dewetting. These results revealed the strong relationship between the dispersion state of the nanofillers and the dewetting of the nanofilled films.     

A study on the synthesis of calix[4 and 6]arenes using alternately arranged phloroglucinols and p-tert-butylphenols

A method for the synthesis of calix[4 and 6]arenes with two or three alternately arranged phloroglucinols and p-tert-butylphenols was studied using "3+1" and "5+1" approaches, compared to a simple one-pot synthesis based on a "1+1" approach. By using Yb(OTf)3 as a catalyst, each calix[4 and 6]arenes was afforded, in an overall yield of 20.7% and 11.8% in the "3+1" and "5+1" approaches, respectively, and 24.6% and 19.9% using a "1+1" approach with chlorobenzene and toluene as refluxing solvents, respectively.     

Quantum processes in short and intensive electromagnetic fields

This work provides an overview of our recent results in studying two most important and widely discussed quantum processes: electron-positron pairs production off a probe photon propagating through a polarized short-pulsed electromagnetic (e.g. laser) wave field or generalized Breit–Wheeler process, and a single a photon emission off an electron interacting with the laser pules, so-called non-linear Compton scattering. We show that the probabilities of particle production in both processes are determined by interplay of two dynamical effects, where the first one is related to the shape and duration of the pulse and the second one is non-linear dynamics of the interaction of charged fermions with a strong electromagnetic field. We elaborate suitable expressions for the production probabilities and cross sections, convenient for studying evolution of the plasma in presence of strong electromagnetic fields.     

Effects of compression on the interaction between 1,4-dihydropyridine compounds and lactose monohydrate (II): differences in powder properties of 1,4-dihydropyridine compounds

The solid-state interaction between manidipine dihydrochloride (Man) or benidipine hydrochloride (Ben) and lactose monohydrate (Lac) was investigated. An endothermic peak area at 170 degrees C was observed when their mixtures were subjected to differential scanning calorimetry (DSC) measurement, and this interaction was accelerated by compression. In the present study, dependency on the particle size of Lac was examined in this solid-state interaction. The DSC peak area at 170 degrees C as a function of the compression force profile was influenced by different particle sizes of Lac in combination with the two medicinal compounds in a different manner. The profile of the onset temperature of Lac dehydration, which indicates the degree of crystalline structure disruption, changed with differing Lac particle size. Moreover, when the particle size of Lac was large, the dehydration onset temperature of Lac with Man decreased from the lower compression force than that of Lac with Ben. The reason for this is thought to be the difference in the powder properties between Man and Ben, although the physicochemical properties of Man and Ben are similar.     

Composite and Elementary Components in Hadron Resonances

In hadron resonances different structures of hadronic composite (molecule) and elementary (quark-intrinsic) natures may coexist. We sketch discussions based on our previous publications on the origin of hadron resonances (Hyodo et al. Phys. Rev. C 78:025203, 2008) on exotic ${\bar D (B)}$ meson–nucleons as candidates of hadronic composites (Yamaguchi et al. Phys. Rev. D 84:014032, 2011) and on a ₁ for the coexistence/mixing of the two different natures (Nagahiro et al. Phys. Rev. D 83:111504, 2011).     

Dynamically Generated Resonances from Two Vectors in the Charm Sector and their Decays

In this talk we study dynamically generated resonances from two-vector mesons within the hidden gauge formalism in a coupled channel unitary approach. We focus on the sectors with charm and/or strangeness and double charm, being some of them flavor exotic. Concretely, by looking for poles in the complex plane, we get three poles in the T-matrix around 2,460, 2,640 and 2,572 MeV that we identify with the ${D^*_2(2,460), D^*(2,640)}$ and ${D^*_{s2}(2,573)}$ , coupling strongly to D*ρ (the first two) and D*K* respectively. In addition, we obtain resonances in other exotic sectors such as (charm = 1; strangeness = ?1), (charm = 2; strangeness = 0, 1). This ’flavor-exotic’ states are interpreted as ${D^*\bar{K}^*, D^*D^*}$ and ${D^*_sD^*}$ molecular states and have not been observed yet. The observation of these peculiar states is a challenge for the experimentalist.     

Optical Reflection Spectra of Silicon Clathrate Compounds Ba8AgxSi46−x

Abstract

Optical reflection spectra are measured for Ba₈Ag_xSi_46?x (0 ≤ x ≤ 6) at room temperature. A systematic decrease in the plasmon energy is found with increasing x, indicating that the carrier concentration decreases with increasing x. When x increases, the superconducting transition temperature T_c decreases. An origin of the decrease in T_c is assigned to the decrease in the density of states at the Fermi level due to the decrease in the carrier concentration.     

Polyanionic Compounds for Potassium‐Ion Batteries

Lithium‐ion batteries have the highest energy density among practical secondary batteries and are widely used for electronic devices, electric vehicles, and even stationary energy‐storage systems. Along with the expansion of demand and applications, the concern about resources of lithium and cobalt is growing. Therefore, secondary batteries composed of abundant elements are required to complement lithium‐ion batteries. In recent years, the development of potassium‐ion batteries has attracted much attention, especially for large‐scale energy storage. In order to realize potassium‐ion batteries, various compounds are proposed and investigated as positive electrode materials, including layered transition‐metal oxides, Prussian blue analogues, and polyanionic compounds. This article offers a review of polyanionic compounds which are typically composed of abundant elements and expected high operating potential. Furthermore, we deliver our new results to partially compensate for lack of studies and provide a future perspective.     

Optimization of a seeded free-electron laser with helical undulators

Seeded single pass free-electron lasers are promising coherent, short-duration, and intense light sources, from the visible to x rays. Operated with adjustable undulators, they are also a unique device for providing fully variable polarized radiation. We report here the first seeding of helical undulators with a variable polarized source. We demonstrate that the adjustment of the seed polarization and focusing allows the free-electron laser radiation to be optimized in terms of intensity and quality.