Tokyo Institute of Technology

About: Tokyo Institute of Technology is a education organization based out in Tokyo, Tôkyô, Japan. It is known for research contribution in the topics: Catalysis & Thin film. The organization has 46775 authors who have published 101656 publications receiving 2357893 citations. The organization is also known as: Tokyo Tech & Tokodai.

Electron performance measurements with the ATLAS detector using the 2010 LHC proton-proton collision data

Abstract: Detailed measurements of the electron performance of the ATLAS detector at the LHC are reported, using decays of the Z, W and J/psi particles. Data collected in 2010 at root s = 7 TeV are used, corresponding to an integrated luminosity of almost 40 pb(-1). The inter-alignment of the inner detector and the electromagnetic calorimeter, the determination of the electron energy scale and resolution, and the performance in terms of response uniformity and linearity are discussed. The electron identification, reconstruction and trigger efficiencies, as well as the charge misidentification probability, are also presented.

Mitochondrial Genome Variation in Eastern Asia and the Peopling of Japan

Abstract: To construct an East Asia mitochondrial DNA (mtDNA) phylogeny, we sequenced the complete mitochondrial genomes of 672 Japanese individuals (http://www.giib.or.jp/mtsnp/index_e.html). This allowed us to perform a phylogenetic analysis with a pool of 942 Asiatic sequences. New clades and subclades emerged from the Japanese data. On the basis of this unequivocal phylogeny, we classified 4713 Asian partial mitochondrial sequences, with <10% ambiguity. Applying population and phylogeographic methods, we used these sequences to shed light on the controversial issue of the peopling of Japan. Population-based comparisons confirmed that present-day Japanese have their closest genetic affinity to northern Asian populations, especially to Koreans, which finding is congruent with the proposed Continental gene flow to Japan after the Yayoi period. This phylogeographic approach unraveled a high degree of differentiation in Paleolithic Japanese. Ancient southern and northern migrations were detected based on the existence of basic M and N lineages in Ryukyuans and Ainu. Direct connections with Tibet, parallel to those found for the Y-chromosome, were also apparent. Furthermore, the highest diversity found in Japan for some derived clades suggests that Japan could be included in an area of migratory expansion to Continental Asia. All the theories that have been proposed up to now to explain the peopling of Japan seem insufficient to accommodate fully this complex picture.

In situ detection of collisionless reconnection in the Earth's magnetotail

Abstract: Magnetic reconnection is the process by which magnetic field lines of opposite polarity reconfigure to a lower-energy state, with the release of magnetic energy to the surroundings. Reconnection at the Earth's dayside magnetopause and in the magnetotail allows the solar wind into the magnetosphere1,2. It begins in a small ‘diffusion region’, where a kink in the newly reconnected lines produces jets of plasma away from the region. Although plasma jets from reconnection have previously been reported3,4,5,6,7, the physical processes that underlie jet formation have remained poorly understood because of the scarcity of in situ observations of the minuscule diffusion region. Theoretically, both resistive and collisionless processes can initiate reconnection8,9,10,11,12,13,14, but which process dominates in the magnetosphere is still debated. Here we report the serendipitous encounter of the Wind spacecraft with an active reconnection diffusion region, in which are detected key processes predicted by models8,9,10,11,12,13 of collisionless reconnection. The data therefore demonstrate that collisionless reconnection occurs in the magnetotail.

Room-temperature miscibility gap in LixFePO4.

Abstract: The rechargeable lithium-ion cell is an advanced energy-storage system. However, high cost, safety hazards, and chemical instability prohibit its use in large-scale applications. An alternative cathode material, LiFePO4, solves these problems, but has a kinetic problem involving strong electron/hole localization1. One reason for this is believed to be the limited carrier density in the fixed monovalent Fe3+PO4/LiFe2+PO4 two-phase electrode reaction in LixFePO4. Here, we provide experimental evidence that LixFePO4, at room temperature, can be described as a mixture of the Fe3+/Fe2+ mixed-valent intermediate LiαFePO4 and Li1−βFePO4 phases. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be α=0.05 and 1−β=0.89. The corresponding solid solution ranges outside the miscibility gap (0