Neutral-fermionic presentation of the K-theoretic Q-function

Journal of Algebraic Combinatorics - We show a new neutral-fermionic presentation of Ikeda-Naruse’s K-theoretic Q-functions, which represent a Schubert class in the K-theory of coherent...     

Copolymerization of Chloroprene with Methyl Methacrylate by the EtnAICI3.n (n=1, 1.5, 2)-Vanadium Compound System

Abstract

The copolymerization of chloroprene with methyl methacrylate was studied in the presence of Et_n A1C1_3-n (n=1, 1.5, 2)-vanadium compounds. Monomer reactivity ratios in various catalyst concentrations were compared with that of a usual radical initiator. The apparent monomer reactivity ratio changed with the concentration of alkylaluminum halide. In this polymerization, alternating copolymer could not be prepared by the ordinary catalyst concentration by which the alternating copolymerization of chloroprene with acrylonitrile was carried out. The addition of more than 10 mole % of the alkylaluminum halide based on two monomers was required to prepare the copolymer which had equimolar composition irrespective of the feed monomer ratio.

The configuration in the repeating unit of the copolymer was discussed by comparison with the NMR and IR spectra of the radical copolymer and the cyclic Diels-Alder adduct of chloroprene-methyl methacrylate. The high alternating tendency was clarified by ozonolysis of the copolymer which was prepared under the conditions which produced equimolar copolymer in various feed monomer ratios. The chloroprene unit of the copolymer was present in the 1, 4-trans structure in the copolymer prepared by the Et_n A1C1_3-n -vanadium compound system.     

1‐Aryl‐4‐Silylmethyl[60]fullerenes: Synthesis,Properties, and Photovoltaic Performance

The efficient nucleophilic addition of aryl Grignard reagents (aryl=4‐MeOC₆H₄, 4‐Me₂NC₆H₄, Ph, 4‐CF₃C₆H₄, and thienyl) to C₆₀ in the presence of DMSO produced 1,2‐arylhydro[60]fullerenes after acid treatment. The reactions of the anions of these arylhydro[60]fullerenes with either dimethylphenylsilylmethyl iodide or dimethyl(2‐isopropoxyphenyl)silylmethyl iodide yielded the target compounds, 1‐aryl‐4‐silylmethyl[60]fullerenes. The properties and structures of these 1‐aryl‐4‐silylmethyl[60]fullerenes (aryl=4‐MeOC₆H₄, thienyl) were examined by electrochemical studies, X‐ray crystallography, flash‐photolysis time‐resolved microwave‐conductivity (FP‐TRMC) measurements, and electron‐mobility measurements by using a space‐charge‐limited current (SCLC) model. Organic photovoltaic devices with a polymer‐based bulk heterojunction structure and small‐molecule‐based p–n and p–i–n heterojunction configurations were fabricated by using 1‐aryl‐4‐silylmethyl[60]fullerenes as an electron acceptor. The most efficient device exhibited a power‐conversion efficiency of 3.4 % (short‐circuit current density: 8.1 mA/ cm², open‐circuit voltage: 0.69 V, fill factor: 0.59).     

Study on selective adsorption of deuterium on boron nitride using photon-stimulated ion-desorption

Adsorption behavior of atomic deuterium on a hexagonal boron nitride (h-BN) thin film is studied by photon-stimulated ion desorption (PSID) of D⁺ and near edge X-ray absorption fine structure (NEXAFS) at the B and N K-edges. After the adsorption of atomic deuterium, D⁺ desorption yield η(hν) shows clear enhancement at the B K-edge and almost no enhancement at the N K-edge. NEXAFS spectra show a large change in the B K-edge and a small change in the N K-edge after the adsorption. We propose selective adsorption of atomic deuterium on the h-BN thin film based on the experimental results, and mention the effectiveness of applying the PSID method with X-ray to study hydrogen storage materials.     

EXCITATION ENERGY TRANSFER IN THE CHROMATICALLY ADAPTED PHYCOBILIN SYSTEMS OF BLUE-GREEN ALGAE: DIFFERENCE IN THE ENERGY TRANSFER KINETICS AT PHYCOCYANIN LEVEL

Abstract— Excitation energy transfer in chromatically adapted phycobilin system was investigated with the blue-green algae Tolypothrix tenuis and, supplementary, Fremyella diplosiphon with use of time-resolved fluorescence spectrum (Yamazaki et al , 1984). Special attention was paid to the energy migration at the phycocyanin (PC) level in the phycoerythrin (PE)-rich and PE excited system and in the PE-less and PC excited system. The energy transfer from PC to allophycocyanin was far faster in the former than in the latter in both organisms. Such feature was the same as our previous observation for PE-rich system of Porphyridium cruentum and PE-less system of Anacystis nidulans (Yamazaki et al , 1984). Thus, the difference in phycobilisome structure is not a cause for such difference. Based on simulation analysis, we interpreted our observation as that (1) all PC chtomophores do not equally participate to the energy migration within PC compartment but (2) a short transfer path through PC compartment is formed probably by f-type chromophores and (3) the difference in the "length" of this path is a main determinant for kinetic difference between PE-rich and PE-less systems.     

Polarization shift keying (POLSK) phase diversity homodyne system with multiplying detection in coherent optical communications

We propose a Polarization Shift Keying (POLSK) phase diversity homo-dyne system with multiplying detection in coherent optical communications. The proposed system uses only one of three Stokes parameters, which is the phase difference between two orthogonal polarizations. Although such systems using only one Stokes parameter are very sensitive to polarization fluctuation, the proposed system becomes insensitive to the linear polarization fluctuation by using the multiplying detection with a combination of in-phase and quadrature optical signal components on two orthogonal polarizations. Furthermore, insensitivity to phase noise and offset frequency and attractiveness due to homodyne type in high-speed transmissions are maintained. The most attractive feature of the proposed system is that neither a polarization controller nor electronic feedback loop for matching the state of polarization (SOP) between transmitted and local oscillator (LO) optical signals is needed. We theoretically analyze the receiver sensitivity and the power penalties of the proposed system for the cases of the elliptical SOP of received optical signals and the imbalance optical 90° hybrid.     

Entropy production and nonequilibrium stationarity in quantum dynamical systems. Physical meaning of van Hove limit

With aid of the so-called dilation method, a concise formula is obtained for the entropy production in the algebraic formulation of quantum dynamical systems. In this framework, the initial ergodic state of an external force system plays a pivotal role in generating dissipativity as a conditional expectation. The physical meaning of van Hove limit is clarified through the scale-changing transformation to control transitions between microscopic and macroscopic levels. It plays a crucial role in realizing the macroscopic stationarity in the presence of microscopic fluctuations as well as in the transition from non-Markovian (groupoid) dynamics to Markovian dissipative processes of state changes. The extension of the formalism to cases with spatial and internal inhomogeneity is indicated in the light of the groupoid dynamical systems and noncommutative integration theory.     

Interactions of counterions with dextran sulfate in aqueous solutions

Counterion activity coefficients in solutions of dextran sulfate with and without added salts were determined potentiometrically by using a cation-exchange membrane and a sodium glass electrode. Dextran sulfate was shown to interact with monovalent cations in the order of preference: K⁺ > Cs⁺ > Na⁺ > Li⁺, whereas no specificity was found for bivalent cations. On the basis of light-scattering measurements, the expansion of the dextran sulfate polyion in solutions of alkali metal salts was found to fall in the same order as the counterion activity coefficients in salt-free solutions. It was also shown that the dextran sulfate polyion assumes a more extended conformation in magnesium chloride solution than in calcium chloride. These results were substantiated by measurements of solution viscosities.