Pseudo-hyperbolic Gauss maps of Lorentzian surfaces in anti-de Sitter space

In this paper, we determine the type numbers of the pseudo-hyperbolic Gauss maps of all oriented Lorentzian surfaces of constant mean and Gaussian curvatures and non-diagonalizable shape operator in the 3-dimensional anti-de Sitter space. Also, we investigate the behavior of type numbers of the pseudo-hyperbolic Gauss map along the parallel family of such oriented Lorentzian surfaces in the 3-dimensional anti-de Sitter space. Furthermore, we investigate the type number of the pseudo-hyperbolic Gauss map of one of Lorentzian hypersurfaces of B-scroll type in a general dimensional anti-de Sitter space.     

Characterization of [ZnO]m[ZnMgO]n multiple quantum wells grown by molecular beam epitaxy

Thermal stability of single-crystalline [ZnO]_m[Zn_0.7Mg_0.3O]_n multiple quantum wells (MQWs) grown on a-plane sapphire substrates by plasma-assisted molecular beam epitaxy is reported. X-ray diffraction analysis revealed that these MQWs were grown as designed with a fixed Zn_0.7Mg_0.3O barrier width of and a series of ZnO well widths of . Cathodoluminescence spectra from these MQWs consisted of two major peaks; one was the emission from the bound excitons in Zn_0.7Mg_0.3O barrier layers, and the other was that from the confined excitons in ZnO well layers. These structural and optical properties were found to be dramatically changed by the ex situ annealing treatments over 700 °C. These changes were presumably due to the onset of phase separation of the Zn_0.7Mg_0.3O barrier layers with pronounced Mg diffusion toward the ZnO wells.     

Study of γ d → π + π − d Reaction in an Energy Region of 0.67 ≤ E γ ≤ 1.08 GeV

Double charged pion photoproductions from the deuteron have been studied at Research Center for Electron Photon Science (ELPH), Tohoku University. Tagged photon beams in an energy range of 0.67 ≤ E _γ ≤ 1.08 GeV were impinged on the liquid deuteron target. Produced charged particles were observed with the Neutral Kaon Spectrometer2 (NKS2). The γ d → π ⁺ π ^? d process was clearly separated among the three charged tracks. We obtained the photon energy dependence of the normalized yields of this process.     

Study of Strangeness Photoproduction on the Neutron in the Threshold Region

Photoproduction of the neutral kaon on the deuteron has been investigated at the Research Center for Electron Photon Science, Tohoku University. We constructed the Neutral Kaon Spectrometer-2 for the detection of charged particles from the decay of the neutral kaon and the hyperon. We obtained a momentum distribution of K ⁰ with the inclusive measurement. It was consistent with the previous measurement. The total cross section of γ + d → K ⁰ + Λ + p was estimated from the measured integral cross section of γ + d → Λ + X. The total cross section with respect to the photon energy was compared with the theoretical calculations. It favored the Saclay-Lyon A model calculation with the ratio of the neutral to charged coupling constants of the axial-vector meson, K ₁, as ~ ?1.5. The energy dependence and the magnitude of the total cross section were similar to the total cross section of γ + p → K ⁺ Λ.     

Real Time Development of Structure in Partially Molten State Stretching of Polypropylene as Detected by Spectral Birefringence Technique: Effect of Isotacticity

The uniaxial deformation behavior of three polypropylene films with isotacticity indices varying from 43 to 95 was investigated in the partially molten state using real time, true stress, true strain, and birefringence measurement system. These polymers generally exhibit three regime stress‐birefringence behaviors during stretching. The unmelted crystalline regions act as physical junctions. If the films contain crystallinity that is too low (less than ca. 10%) the Regime I disappears. Under these conditions, the films were found to exhibit large linearity in strain and stress optical behavior. If, however, too low a deformation rate is employed, these relationships become non‐linear.

The increase of isotacticity increases the magnitude of the birefringence at all deformation levels primarily as a result of the increase in crystallinity that helps in establishing a long‐range physical network. This increase in the long‐range connectivity was found to promote not only the orientation in crystalline domains but also in the amorphous domains. The increased long‐range connectivity in high isotacticity films was also found to result in destruction of local initial structures that generate a large fraction of the oriented amorphous chain regions. This translates into larger stress decrease and birefringence increase changes during the holding stage where the oriented amorphous chains undergo complex relaxation/oriented crystallization processes.     

Inhomogeneous superconducting state in the overdoped regime of La2−xSrxCuO4: Comparison with the superconducting state of NbSe2

We have measured the temperature dependence of the magnetic susceptibility, χ vs. T, and the magnetization curve, M vs. H, for NbSe₂ single crystals, in order to compare the superconducting (SC) state in the overdoped regime of La_2−xSr_xCuO₄ (LSCO) with the SC state of the layered conventional superconductor NbSe₂. While a plateau in χ vs. T in a moderate magnetic field and a so-called second peak in M vs. H, which is due to the marked enhancement of vortex pinning, have been observed in the overdoped regime of LSCO, these behaviors have not been observed in NbSe₂. The present results indicate that the anomalously marked enhancement of vortex pinning is a characteristic feature in the overdoped LSCO where a microscopic phase separation into SC and normal-state regions takes place.     

Damping constant of Co/Pt multilayer thin-film media

Gilbert's damping constants, α, of Co(t_Co)/Pt (1.4 nm) multilayer thin films are investigated by Q-band FMR analysis. α is calculated from the resonance width of the FMR spectrum. With decreasing t_Co, the α value decreases from 0.034 (t_Co=8.7 nm) to 0.023 (t_Co=1.8 nm), and then increases to 0.037 (t_Co=1.0 nm). The decrease of α with t_Co>1.8 nm is probably due to the eddy current loss effects. The increase of α with t_Co<1.8 nm would be caused by the increase of the distortion between the Co and the Pt layers at the interface. When the magnetic field direction was changed from θ=90° (parallel to the specimen) to θ=0° (perpendicular to the specimen), the α of all the specimens increased, and a sharp step in α was observed around θ=40°, where the α has the maximum value.     

Exponential structural relaxation of a high purity silica glass

While most other glasses exhibit non-exponential structural relaxation characteristics even when the change of fictive temperature is small, a high purity silica glass exhibited exponential structural relaxation. This was demonstrated by showing that the non-exponential exponent or β value of the KWW function of the high purity silica glass approaches unity when the change of the fictive temperature approaches zero both from higher and lower temperature sides of the heat-treatment temperature. The non-exponentiality of the structural relaxation of this glass when fictive temperature change is finite is due to the change of relaxation time during the structural relaxation.     

Optimizing Charge Switching in Membrane Lytic Peptides for Endosomal Release of Biomacromolecules

Endocytic pathways are practical routes for the intracellular delivery of biomacromolecules. Along with this, effective strategies for endosomal cargo release into the cytosol are desired to achieve successful delivery. Focusing on compositional differences between the cell and endosomal membranes and the pH decrease within endosomes, we designed the lipid-sensitive and pH-responsive endosome-lytic peptide HAad. This peptide contains aminoadipic acid (Aad) residues, which serve as a safety catch for preferential permeabilization of endosomal membranes over cell membranes, and His-to-Ala substitutions enhance the endosomolytic activity. The ability of HAad to destabilize endosomal membranes was supported by model studies using large unilamellar vesicles (LUVs) and by increased intracellular delivery of biomacromolecules (including antibodies) into live cells. Cerebral ventricle injection of Cre recombinase with HAad led to Cre/loxP recombination in a mouse model, thus demonstrating potential applicability of HAad in vivo.     

On the rate of convergence of solutions in free boundary problems via penalization

The rate of convergence of approximate solutions via penalization for free boundary problems are concerned. A key observation is to obtain global bounds of penalized terms which give necessary estimates on integrations by the nonlinear adjoint method by L.C. Evans.