Experimental and Atomistic Theoretical Study of Degree of Polarization from Multi-layer InAs/GaAs Quantum Dots

Recent experimental measurements, without any theoretical guidance, showed that isotropic polarization response can be achieved by increasing the number of QD layers in a QD stack. Here we analyse the polarization response of multi-layer quantum dot stacks containing up to nine quantum dot layers by linearly polarized PL measurements and by carrying out a systematic set of multi-million atom simulations. The atomistic modeling and simulations allow us to include correct symmetry properties in the calculations of the optical spectra: a factor critical to explain the experimental evidence. The values of the degree of polarization (DOP) calculated from our model follows the trends of the experimental data. We also present detailed physical insight by examining strain profiles, band edges diagrams and wave function plots. Multi-directional PL measurements and calculations of the DOP reveal a unique property of InAs quantum dot stacks that the TE response is anisotropic in the plane of the stacks. Therefore a single value of the DOP is not sufficient to fully characterize the polarization response. We explain this anisotropy of the TE-modes by orientation of hole wave functions along the [-110] direction. Our results provide a new insight that isotropic polarization response measured in the experimental PL spectra is due to two factors: (i) TM[001]-mode contributions increase due to enhanced intermixing of HH and LH bands, and (ii) TE[110]-mode contributions reduce significantly due to hole wave function alignment along the [-110] direction. We also present optical spectra for various geometry configurations of quantum dot stacks to provide a guide to experimentalists for the design of multi-layer QD stacks for optical devices. Our results predict that the QD stacks with identical layers will exhibit lower values of the DOP than the stacks with non-identical layers.Comment: 10 pages, 7 figures, and 1 tabl

GROUND REACTION FORCES DURING THE GOLF SWING USING DIFFERENT GOLF CLUBS IN FEMALE GOLFERS

The purpose of this study was to investigate effects of different golf clubs on the ground reaction forces during the golf swing for females. Ten right-handed female varsity golfers voluntarily participated in this study. Using three different clubs, they hit the ball by their own swing in four conditions (full driver shot, controlled driver shot, 6-iron shot, and approach-wedge shot). Their motion was three-dimensionally captured which was performed with one foot on each force plate. There were no significant differences in the peak resultant forces between the golf clubs, but the peak resultant horizontal force differed between the golf clubs. The female golfers’ resultant reaction force patterns were classified into three patterns, indicating that the golfers generated the reaction forces in their own ways, which would reflect the characteristics of their golf swing

VLBI Monitoring of 3C 84 (NGC 1275) in Early Phase of the 2005 Outburst

Multi-epoch Very Long Baseline Interferometry (VLBI) study of the sub-pc scale jet of 3C 84 is presented. We carried out 14-epoch VLBI observations during 2006-2009 with the Japanese VLBI Network (JVN) and the VLBI Exploration of Radio Astrometry (VERA), immediately following the radio outburst that began in 2005. We confirmed that the outburst was associated with the central ~1 pc core, accompanying the emergence of a new component. This is striking evidence of the recurrence of jet activity. The new component became brighter during 2008, in contrast to the constant gamma-ray emission that was observed with the Fermi Gamma-ray Space Telescope during the same time. We found that the projected speed of the new component is 0.23c from 2007/297 (2007 October 24) to 2009/114 (2009 April 24). The direction of movement of this component differs from that of the pre-existing component by ~40 degree. This is the first measurement of kinematics of a sub-pc jet in a gamma-ray active phase. Possible detection of jet deceleration and the jet kinematics in connection with the gamma-ray emission is discussed.Comment: 5 pages, 3 figures. Accepted for publication in PAS

Instagramのコミュニケーションの役割と使用方法についての探索的調査―社会的/情報的ベネフィットと処理流暢性の視点からのInstagramの機能の分類―

application/pdf一般論文departmental bulletin pape

The Effect of Text and Photographs on Product Evaluation on the Internet : Extension of the Elaboration Likelihood Model Based on the Processing Fluency of the Information Provided

application/pdfThis study clarifies the effects of processing fluency of information (sentences and product photos) on product evaluation in communication on the Internet. First, the author divided the text message (verbal information) into attribute information and benefit information, and added pictures (non-verbal information), and classified them into attribute information, benefit information, and pictures in order of decreasing processing fluency. Then, using classification on processing fluency, this study aimed to extend the Elaboration Likelihood Model (ELM). In Study 1, the author analyzed the effects of (a) the presence or absence of pictures and (b) attribute/benefit information on product evaluation, moderated by the receiver’s level of expertise. In Study 2, to further examine the effect of the photos used in Study 1, the author conducted a comparative analysis of photos with high and low attractiveness. The aim of this study was to extend the ELM based on the processing fluency of the information and to examine the effects of text and photos on product evaluation in word-of-mouth communication on the Internet.departmental bulletin pape

Purkinje cells originate from cerebellar ventricular zone progenitors positive for Neph3 and E-cadherin

AbstractGABAergic Purkinje cells (PCs) provide the primary output from the cerebellar cortex, which controls movement and posture. Although the mechanisms of PC differentiation have been well studied, the precise origin and initial specification mechanism of PCs remain to be clarified. Here, we identified a cerebellar and spinal cord GABAergic progenitor-selective cell surface marker, Neph3, which is a direct downstream target gene of Ptf1a, an essential regulator of GABAergic neuron development. Using FACS, Neph3+ GABAergic progenitors were sorted from the embryonic cerebellum, and the cell fate of this population was mapped by culturing in vitro. We found that most of the Neph3+ populations sorted from the mouse E12.5 cerebellum were fated to differentiate into PCs while the remaining small fraction of Neph3+ cells were progenitors for Pax2+ interneurons, which are likely to be deep cerebellar nuclei GABAergic neurons. These results were confirmed by short-term in vivo lineage-tracing experiments using transgenic mice expressing Neph3 promoter-driven GFP. In addition, we identified E-cadherin as a marker selectively expressed by a dorsally localized subset of cerebellar Neph3+ cells. Sorting experiments revealed that the Neph3+ E-cadherinhigh population in the embryonic cerebellum defined PC progenitors while progenitors for Pax2+ interneurons were enriched in the Neph3+ E-cadherinlow population. Taken together, our results identify two spatially demarcated subregions that generate distinct cerebellar GABAergic subtypes and reveal the origin of PCs in the ventricular zone of the cerebellar primordium