The Belle Silicon Vertex Detector

The silicon vertex detector of the Belle experiment has been built to provide the vertex information of $B$ meson decays at the KEKB accelerator. Performance during the initial data taking period and a brief description of the upgrade plan are also presented.Comment: To appear in the Proceedings of the 4th International Symposium on Development and Application of Semiconductor Tracking Detectors, March 22 - 25, 2000 Hiroshima, Japa

Partially-disordered photonic-crystal thin films for enhanced and robust photovoltaics

We present a general framework for the design of thin-film photovoltaics based on a partially-disordered photonic crystal that has both enhanced absorption for light trapping and reduced sensitivity to the angle and polarization of incident radiation. The absorption characteristics of different lattice structures are investigated as an initial periodic structure is gradually perturbed. We find that an optimal amount of disorder controllably introduced into a multi-lattice photonic crystal causes the characteristic narrow-band, resonant peaks to be broadened resulting in a device with enhanced and robust performance ideal for typical operating conditions of photovoltaic applications.Comment: 5 pages, 4 figure

Slowed response to peripheral visual stimuli during strenuous exercise

Recently, we proposed that strenuous exercise impairs peripheral visual perception because visual responses to peripheral visual stimuli were slowed during strenuous exercise. However, this proposal was challenged because strenuous exercise is also likely to affect the brain network underlying motor responses. The purpose of the current study was to resolve this issue. Fourteen participants performed a visual reaction-time (RT) task at rest and while exercising at 50% (moderate) and 75% (strenuous) peak oxygen uptake. Visual stimuli were randomly presented at different distances from fixation in two task conditions: the Central condition (2° or 5° from fixation) and the Peripheral condition (30° or 50° from fixation). We defined premotor time as the time between stimulus onset and the motor response, as determined using electromyographic recordings. In the Central condition, premotor time did not change during moderate (167 ± 19 ms) and strenuous (168 ± 24 ms) exercise from that at rest (164 ± 17 ms). In the Peripheral condition, premotor time significantly increased during moderate (181 ± 18 ms, P < 0.05) and strenuous exercise (189 ± 23 ms, P < 0.001) from that at rest (173 ± 17 ms). These results suggest that increases in Premotor Time to the peripheral visual stimuli did not result from an impaired motor-response network, but rather from impaired peripheral visual perception. We conclude that slowed response to peripheral visual stimuli during strenuous exercise primarily results from impaired visual perception of the periphery

SPADExp: A photoemission angular distribution simulator directly linked to first-principles calculations

We develop a software package SPADExp (simulator of photoemission angular distribution for experiments) to calculate the photoemission angular distribution (PAD), which is the momentum dependence of spectrum intensity in angle-resolved photoemission spectroscopy (ARPES). The software can directly load the output of the first-principles software package OpenMX, so users do not need to construct tight-binding models as previous studies did for PAD calculations. As a result, we can calculate the PADs of large systems such as quasicrystals and slab systems. We calculate the PADs of sublattice systems (graphene and graphite) to reproduce characteristic intensity distributions, which ARPES has experimentally observed. After that, we investigate twisted bilayer graphene, a quasicrystal showing 12-fold rotational symmetric spectra in ARPES, and the surface states of the topological insulator $\mathrm{Bi}_2\mathrm{Se}_3$. Our calculations show good agreement with previous ARPES measurements, showing the correctness of our calculation software and further potential to investigate the photoemission spectra of novel quantum materials.Comment: 19 pages, 5 figures, Software has been developed in https://github.com/Hiroaki-Tanaka-0606/SPADEx