Formation mechanism of one-dimensional Si islands on a H/Si(001) surface

The formation mechanism of one-dimensional Si islands on a H/Si(001)-(2x1) surface is studied using scanning tunneling microscopy/spectroscopy and first-principles calculations. We observed that one-dimensional islands that are made from dimer chains are formed at the initial growth stages similar to the bare Si(001) surface. It is found that the number of odd-numbered dimer chains is larger than that of even-numbered dimer chains. We propose the growth processes of the two types of growth edges to explain the observation.     

Two-Dimensional Multi-Lens Array with Circular Aperture Spherical Lens for Flat-Top Irradiation of Inertial Confinement Fusion Target

A two-dimensional multi-lens array 350 mm in diameter with spherical element lenses has been tested to improve the irradiation uniformity of a high power glass laser for inertial confinement fusion (ICF). A circular shape for the element lens aperture is chosen to eliminate azimuthally asymmetric intensity distribution. An approximate flat-top intensity distribution is obtained with a lens array of 37 lenses. Beam patterns of a coherent laser and partially coherent light (PCL) with the random phase plate (RPP) and the multi-lens array (MLA) are measured in a GEKKO XII glass laser system. Spherical mode structure of the irradiation nonuniformity of 5.6% with MLA is estimated with cos3 θ distribution of absorption coefficient in the target plasma.     

Stable oscillations of a spatially chaotic wave function in a microstadium laser

Laser action on a single spatially chaotic wave function is obtained as a final stable state in a nonlinear dynamical model of a stadium shaped resonant cavity with an active medium. The stable single-mode lasing state corresponds to a particular metastable resonance of the cavity which wins a competition among multiple modes with positive net linear gain and has a distinct lasing threshold.     

Improvement of Laser-Beam Irradiation-Intensity Distribution Using Multi Lens Array and Edge-Shaped Plates

A new concept for improving the laser intensity distribution on an inertial confinement fusion target using a phase-controlled multi lens array has been proposed. Circular and hexagonal element lens apertures have been examined, and the circular aperture which eliminated azimuthally asymmetric intensity distribution was chosen. The diffraction fringe of the elementary lens was mitigated in a one-dimensional lens array using edge-shaped plates of a super-Gaussian phase profile. Uniform beam profiles were obtained using a one-dimensional array with 7 spherical lenses and a two-dimensional array with 37 lenses. An approximately flat-top intensity distribution was realized with the lens array with 37 lenses.     

Asymmetric stationary lasing patterns in 2D symmetric microcavities

Locking of two resonance modes of different symmetry classes and different frequencies in 2D resonant microcavity lasers is investigated by using a nonlinear dynamical model. The patterns of stationary lasing states and far fields are asymmetric in spite of the symmetric shape of the resonant microcavity. The corresponding phenomenon is actually observed in the experiment of a 2D semiconductor microcavity laser diode.     

Anticorrelated bidirectional output of quasistadium-shaped semiconductor microlasers

Time-domain properties of the output from quasistadium-shaped microcavity semiconductor lasers are studied. Ring modes generating a bidirectional output are selectively excited by partial pumping. We observe a high anticorrelation between the two beams output from the ring modes. This can be considered as the generalization of alternate oscillations reported previously. We find that the outputs exhibit a robust slow modulation of 4–10 MHz, and explain it by the quasi-degeneracy of the resonator modes.     

Formation of Essential Kaonic Nuclei, “K − pp”

We have reviewed our theoretical calculations of the formation of a deeply bound K ^? pp state with I = 1/2, J ^π  = 0^? by the ³He(in-flight K ^?, n) reaction at ${p_{K^-} = 1.0}$ rm GeV/c and θ _lab = 0° for the forthcoming J-PARC E15 experiment. The expected inclusive and semiexclusive spectra have been calculated within the framework of a distorted-wave impulse approximation using the Green’s function method. The advantage of the use of the ³He target for the ³He(K ^?, N) reactions are emphasized.     

Shape aspherical compacta-applications of a theorem of Kan and Thurston to cohomological dimension and shape theories

Dydak and Yokoi introduced the notion of shape aspherical compactum. In this paper, we use this notion to obtain a generalization of Kan and Thurston theorem for compacta and pro-homology. As an application, we obtain a characterization of cohomological dimension with coefficients in and ( prime) in terms of acyclic maps from a shape aspherical compactum, which improves the theorems of Edwards and Dranishnikov. Furthermore, we obtain the shape version of the theorem and as a consequence we show that every compactum has the stable shape type of a shape aspherical compactum.

     

Bacopasides III-V: three new triterpenoid glycosides from Bacopa monniera

Three new saponins, designated as bacopasides III, IV and V have been isolated from Bacopa monniera WETTST. and their structures have been elucidated as 3-O-alpha-L-arabinofuranosyl (1-->2)-beta-D-glucopyranosyl jujubogenin (1), 3-O-beta-D-glucopyranosyl (1-->3)-alpha-L-arabinopyranosyl jujubogenin (2) and 3-O-beta-D-glucopyranosyl (1-->3)-alpha-L-arabinopyranosyl pseudojujubogenin (3) mainly on the basis of two dimensional (2D) NMR and other spectral analyses.     

On the nonlinear dynamics in the oxidation of CO on Pt(100) and Pt(110) surfaces: Forced oscillations

The effects of low-amplitude periodic modulation of oxygen pressure on the catalytic oxidation on Pt(100) and Pt(110) are investigated with the aid of a set of kinetic equations derived by Cox, Ertl and Imbihl. In the response of the system, subharmonic and superharmonic entrainment bands are found in addition to the fundamental entrainment band. Furthermore, quasiperiodic oscillations are obtained between the entrainment bands.