The topology of restricted partition posets

For each composition $\vec {c}$ we show that the order complex of the poset of pointed set partitions  $\varPi^{\bullet}_{\vec {c}}$ is a wedge of spheres of the same dimension with the multiplicity given by the number of permutations with descent composition $\vec {c}$ . Furthermore, the action of the symmetric group on the top homology is isomorphic to the Specht module S ^B where B is a border strip associated to the composition. We also study the filter of pointed set partitions generated by a knapsack integer partition and show the analogous results on homotopy type and action on the top homology.     

Understanding the mechanism of direct visible-light-activated [2 + 2] cycloadditions mediated by Rh and Ir photocatalysts: combined computational and spectroscopic studies

The mechanism of [2 + 2] cycloadditions activated by visible light and catalyzed by bis-cyclometalated Rh(iii) and Ir(iii) photocatalysts was investigated, combining density functional theory calculations and spectroscopic techniques. Experimental observations show that the Rh-based photocatalyst produces excellent yield and enantioselectivity whereas the Ir-photocatalyst yields racemates. Two different mechanistic features were found to compete with each other, namely the direct photoactivation of the catalyst–substrate complex and outer-sphere triplet energy transfer. Our integrated analysis suggests that the direct photocatalysis is the inner working of the Rh-catalyzed reaction, whereas the Ir catalyst serves as a triplet sensitizer that activates cycloaddition via an outer-sphere triplet excited state energy transfer mechanism.

The mechanism of [2 + 2] cycloadditions activated by visible light and catalyzed by bis-cyclometalated Rh(iii) and Ir(iii) photocatalysts was investigated, combining density functional theory calculations and spectroscopic techniques.     

Size-dependent chemical transformation,structural phase change,and optical properties of nanowires

Nanowires offer a unique approach for the bottom-up assembly of electronic and photonic devices with the potential of integrating photonics with existing technologies. The anisotropic geometry and mesoscopic length scales of nanowires also make them very interesting systems to study a variety of size-dependent phenomenon where finite-size effects become important. We will discuss the intriguing size-dependent properties of nanowire systems with diameters in the 5–300?nm range, where finite-size and interfacial phenomena become more important than quantum mechanical effects. The ability to synthesize and manipulate nanostructures by chemical methods allows tremendous versatility in creating new systems with well-controlled geometries, dimensions, and functionality, which can then be used for understanding novel processes in finite-sized systems and devices.     

Two-dimensional modeling of optical transmission on the surface of a lenticular array for autostereoscopic displays

In this study, we suggest a customized model describing optical phenomena at the surface of a lenticular array for autostereoscopic displays in a mathematical form and analyzed the optical characteristics of lenticular array for the first time. We checked the validity of our mathematical model by examining and comparing our result with conventional lens theory. Monte Carlo simulations were performed to obtain the angular distribution of light from each sub-pixel corresponding to each views under actual design conditions. From the results, we think the optical model is very useful for designing optical parameters of autostereoscopic displays.     

Dynamic susceptibility of thin films with perpendicular magnetic anisotropy

We investigate the spin dynamics related to the Gilbert damping constant in infinite continuous thin films with perpendicular magnetic anisotropy (PMA), based on numerical and analytic approaches. We obtain the dynamic susceptibility of the infinite continuous thin films with various PMA energies by using micromagnetic simulations with periodic boundary conditions. These results are compared with the analytic solution that we derived from the Landau–Lifshitz–Gilbert equation. Based on our numerical and analytic studies, we support the physical analysis for results in the experimental determination of the Gilbert damping constant for PMA materials.     

High performance Zn–Sn–O thin film transistors with Cu source/drain electrode

Zn–Sn–O (ZTO) thin film transistors (TFTs) were fabricated with a Cu source/drain electrode. Although a reasonably high mobility (μ_FE) of 13.2 cm²/Vs was obtained for the ZTO TFTs, the subthreshold gate swing (SS) and threshold voltage (V_th) of 1.1 V/decade and 9.1 V, respectively, were inferior. However, ZTO TFTs with Ta film inserted as a diffusion barrier, exhibited improved SS and V_th values of 0.48 V/decade and 3.0 V, respectively as well as a high μ_FE value of 18.7 cm²/Vs. The improvement in the Ta‐inserted device was attributed to the suppression of Cu lateral diffusion into the ZTO channel region. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Air stability of PTCDI‐C13‐based n‐OFETs on polymer interfacial layers

This Letter reports the novel use of poly(9‐vinylcarbazole) (PVK) as a dielectric interfacial layer for n‐type organic field‐effect transistors (n‐OFETs). With PVK, both the air stability and electron mobility of N,N′‐ditridecylperylene‐3,4,9,10‐tetracarboxylic diimide (PTCDI‐C13)‐based OFETs were improved. Among the PVKs with different weight‐average molecular weight (M_w), PVK with high M_w showed good performance. The high glass transition temperature of PVK enabled thermal post annealing of the active layer, which resulted in a high electron mobility of 0.61 cm²/Vs. This mobility was maintained at 90% and 59% after 4 days and 105 days in air, respectively. The PVK interfacial layer reduced the trapped charges in the PTCDI‐C13‐based n‐OFET for air‐exposure and caused a decrease in the threshold voltage shift.

     

Pion–Rho Meson Lagrangian in Nuclear Matter

We present an in-medium modified pion and rho meson Lagrangian which describes the pion, rho meson and the corresponding soliton properties in nuclear matter. Within the present approach pion properties in nuclear matter is closely related to the low-energy pion-nucleus scattering phenomenology. We discuss the possible modifications of rho meson properties in nuclear matter.     

K* 0 Σ+ Photoproduction with Evidence for the Kappa Meson Exchange at SPring-8/LEPS

Recently, LEPS collaboration reported the parity spin asymmetry for the γ p → K* ⁰Σ⁺ reaction using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. The parity spin asymmetry ( ${P_{\sigma} = 2\rho^{1}_{1-1} - \rho^{1}_{00}}$ ) was obtained, with large positive asymmetry at forward angles. This supports that natural-parity exchange is dominant at forward angles for K* ⁰Σ⁺ photoproduction, which is consistent with κ meson-exchange. The differential cross sections for the γ p → K* ⁰Σ⁺ reaction are presented at forward angles averaged over all beam energies. There is good agreement with the differential cross sections from the CLAS and the CBELSA/TAPS collaborations.     

Flux intensity functions for the Laplacian at axisymmetric edges

We derive explicit representation formulas for the computation of flux intensity functions for mixed boundary value problems for the Poisson equation in axisymmetric domains with edges. We rely on the decomposition of the boundary value problems in three dimensions by means of partial Fourier analysis with respect to the rotational angle into boundary value problems in the two‐dimensional meridian domain of . Utilizing smooth cutoff functions, the solutions of the reduced problems are analyzed semi‐analytically near corners of the plane meridian domain, and the edge flux intensity functions are constructed via Fourier synthesis and convergence analysis. The formulas are also applicable in the case of crack fronts. The constructive nature of the formulas provides in a straightforward way an efficient strategy for the accurate computation of edge flux intensity functions in axisymmetric domains. A demonstration example that illustrates the application of the formulas is presented. Copyright © 2012 John Wiley & Sons, Ltd.