Showing papers by "Tokyo Institute of Technology published in 2006"

Final report of the E821 muon anomalous magnetic moment measurement at BNL

Abstract: We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a(mu)=(g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a(mu)(Expt)=11659208.0(5.4)(3.3)x10(-10), where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a(mu) includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, approximate to 0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e(+)e(-) hadronic cross sections, lie 2.2-2.7 standard deviations below the experimental result.

Pvclust: an R package for assessing the uncertainty in hierarchical clustering

Abstract: Summary: Pvclust is an add-on package for a statistical software R to assess the uncertainty in hierarchical cluster analysis. Pvclust can be used easily for general statistical problems, such as DNA microarray analysis, to perform the bootstrap analysis of clustering, which has been popular in phylogenetic analysis. Pvclust calculates probability values (p-values) for each cluster using bootstrap resampling techniques. Two types of p-values are available: approximately unbiased (AU) p-value and bootstrap probability (BP) value. Multiscale bootstrap resampling is used for the calculation of AU p-value, which has superiority in bias over BP value calculated by the ordinary bootstrap resampling. In addition the computation time can be enormously decreased with parallel computing option. Availability: The program is freely distributed under GNU General Public License (GPL) and can directly be installed from CRAN (http://cran.r-project.org/), the official R package archive. The instruction and program source code are available at http://www.is.titech.ac.jp/~shimo/prog/pvclust Contact: ryota.suzuki@is.titech.ac.jp

Amorphous Oxide Semiconductors for High-Performance Flexible Thin-Film Transistors

Abstract: Recently, we have demonstrated the potential of amorphous oxide semiconductors (AOSs) for developing flexible thin-film transistors (TFTs). A material exploration of AOSs desired as the channel layer in TFTs is most important for developing high-performance devices. Here, we report our concept of material exploration for AOSs in high-performance flexible and transparent TFTs from the viewpoints of chemical bonding and electronic structure in oxide semiconductors. We find that amorphous In–Ga–Zn–O (a-IGZO) exhibits good carrier transport properties such as reasonably high Hall mobilities (>10 cm2V-1s-1) and a good controllability of carrier concentration from <1015 to 1020 cm-3. In addition, a-IGZO films have better chemical stabilities in ambient atmosphere and at temperatures up to 500 °C. The flexible and transparent TFT fabricated using a-IGZO channel layer at room temperature operated with excellent performances, such as normally-off characteristics, on/off current ratios (~106) and field-effect mobilities (~10 cm2V-1s-1), which are higher by an order of magnitude than those of amorphous Si:H and organics TFTs.

Light-emitting device

Abstract: An object of the present invention is to provide a new light-emitting device with the use of an amorphous oxide. The light-emitting device has a light-emitting layer existing between first and second electrodes and a field effect transistor, of which the active layer is an amorphous.

Iron-Based Layered Superconductor: LaOFeP

Abstract: We report superconductivity in an iron-based layered oxy-pnictide LaOFeP. LaOFeP is composed of an alternate stack of lanthanum oxide (La3+O2-) and iron pnictide (Fe2+P3-) layers. Magnetic and electrical resistivity measurements verify the occurrence of the superconducting transition at ∼4 K.

Ionic amorphous oxide semiconductors: Material design, carrier transport, and device application

Abstract: Recently we have reported the room temperature fabrication of transparent and flexible thin film transistors on a polyethylene terephthalate (PET) film substrate using an ionic amorphous oxide semiconductor (IAOS) in an In2O3–ZnO–Ga2O3 system. These transistors exhibit a field effect mobility of ∼10 cm2 (V s)−1, which is higher by an order of magnitude than those of hydrogenated amorphous Si and pentacene transistors. This article describes a chemical design concept of IAOS, and its unique electron transport properties, and electronic structure, by comparing them with those of conventional amorphous semiconductors. High potential of IAOS for flexible electronics is addressed.

Weak-localization magnetoresistance and valley symmetry in graphene.

Abstract: Because of the chiral nature of electrons in a monolayer of graphite (graphene) one can expect weak antilocalization and a positive weak-field magnetoresistance in it. However, trigonal warping (which breaks $\mathbf{p}\ensuremath{\rightarrow}\ensuremath{-}\mathbf{p}$ symmetry of the Fermi line in each valley) suppresses antilocalization, while intervalley scattering due to atomically sharp scatterers in a realistic graphene sheet or by edges in a narrow wire tends to restore conventional negative magnetoresistance. We show this by evaluating the dependence of the magnetoresistance of graphene on relaxation rates associated with various possible ways of breaking a ``hidden'' valley symmetry of the system.

Screening Effect and Impurity Scattering in Monolayer Graphene

Abstract: The static polarization function is calculated in two-dimensional graphite and used for the calculation of the conductivity limited by charged-impurity scattering. The conductivity increases in proportion to the electron concentration and the mobility remains independent of the Fermi energy, in qualitative agreement with experiments. The screening increases in proportion to temperature at sufficiently high temperatures in contrast to the behavior in conventional two-dimensional systems, leading to the mobility increase proportional to the square of temperature.

Bent-Core Liquid Crystals: Their Mysterious and Attractive World

Abstract: Structures and properties of liquid crystalline phases formed by bent-core molecules are reviewed. At least eight phases designated as B1–B8 have been found, being unambiguously distinguished from phases formed by usual calamitic molecules due to a number of remarkable peculiarities. In addition to B1–B8 phases, smectic A-like phases and biaxial nematic phases formed by bent-core molecules are also reviewed. The most attractive aspects of this new class of liquid crystals are in polarity and chirality, despite being formed from achiral molecules. The bent-core mesogens are the first ferroelectric and antiferroelectric liquid crystals realized without introducing chirality. Spontaneous chiral deracemization at microscopic and macroscopic levels occurs and is controllable. Moreover, achiral bent-core molecules enhance system chirality. The interplay between polarity and chirality provides chiral nonlinear optic effects. Further interesting phenomena related to polarity and chirality are also reviewed.

Bifunctional transition metal-based molecular catalysts for asymmetric syntheses.

Abstract: The discovery and development of conceptually new chiral bifunctional transition metal-based catalysts for asymmetric reactions is described. The chiral bifunctional Ru catalyst was originally developed for asymmetric transfer hydrogenation of ketones and imines and is now successfully applicable to enantioselective C–C bond formation reaction with a wide scope and high practicability. The deprotonation of 1,3-dicarbonyl compounds with the chiral amido Ru complexes leading to the amine Ru complexes bearing C- or O-bonded enolates, followed by further reactions with electrophlies gives C–C bond formation products. The present bifunctional Ru catalyst offers a great opportunity to open up new fundamentals for stereoselective molecular transformation including enantioselective C–H and C–C as well as C–O, C–N bond formation.

Sums of Squares and Semidefinite Program Relaxations for Polynomial Optimization Problems with Structured Sparsity

Abstract: Unconstrained and inequality constrained sparse polynomial optimization problems (POPs) are considered. A correlative sparsity pattern graph is defined to find a certain sparse structure in the objective and constraint polynomials of a POP. Based on this graph, sets of the supports for sums of squares (SOS) polynomials that lead to efficient SOS and semidefinite program (SDP) relaxations are obtained. Numerical results from various test problems are included to show the improved performance of the SOS and SDP relaxations.

Catalytic properties of hierarchical mesoporous zeolites templated with a mixture of small organic ammonium salts and mesoscale cationic polymers.

Abstract: Crystals of zeolites with intricate micropores have been widely used in industry as heterogeneous catalysts, in particular as solid acid catalysts in the fields of oil refining and petrochemistry. However, relatively small individual micropores in zeolites such as Beta, ZSM-5, and Y strongly influence mass transport to and from the active sites located within them, severely limiting the performance of industrial catalysts.[1,2] To overcome this problem, various strategies have been successfully pursued, such as the synthesis of nanosized zeolites,[3] ultralarge-pore zeolites and zeolite analogues (VPI-5,[4] JDF-20,[5] UTD-1,[6, 7] CIT-5,[8] SSZ-53,[9] ECR-34,[10] UCSB,[11] ITQ-21,[12] IM-12,[13] and SU-M,[14, 15] among others), and ordered mesoporous materials (e.g. MCM-41,[17] SBA-15,[18] and FSM-16,[19]). However, the use of these materials is rather limited owing to the difficult separation of nanosized zeolite crystals from the reaction mixture,[3] the complexity of the templates used for the synthesis of ultralarge-pore zeolites,[6–9] and the relatively low thermal and hydrothermal stability of ordered mesoporous materials.[17–28] More recently, mesoporous zeolites from nanosized carbon templates have also been successfully synthesized,[29–32] but their industrial applications are still limited by the complexity of the synthetic procedure involved and the hydrophobicity of the carbon templates.

Acid-Catalyzed Reactions on Flexible Polycyclic Aromatic Carbon in Amorphous Carbon

Abstract: Carbonization of d-glucose at 573−723 K followed by sulfonation produces a functionalized amorphous carbon material with acid catalytic activity as a solid-acid replacement for sulfuric acid. The carbon material contains phenolic hydroxyl, carboxylic acid, and sulfonic acid groups and exhibits high catalytic performance for liquid-phase acid-catalyzed reactions. Carbonization at higher temperature followed by sulfonation also results in amorphous carbon, but the resultant does not exhibit catalytic activity although the amorphous carbon has sufficient amount of sulfonic acid groups. Structural and active site analyses suggest that the marked difference in catalytic activity is due to the accessibility of reactants to sulfonic acid groups in the carbon structure.

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

Flyback-Type Single-Phase Utility Interactive Inverter With Power Pulsation Decoupling on the DC Input for an AC Photovoltaic Module System

Abstract: In recent years, interest in natural energy has grown in response to increased concern for the environment. Many kinds of inverter circuits and their control schemes for photovoltaic (PV) power generation systems have been studied. A conventional system employs a PV array in which many PV modules are connected in series to obtain sufficient dc input voltage for generating ac utility line voltage from an inverter circuit. However, the total power generated from the PV array is sometimes decreased remarkably when only a few modules are partially covered by shadows, thereby decreasing inherent current generation, and preventing the generation current from attaining its maximum value on the array. To overcome this drawback, an ac module strategy has been proposed. In this system, a low-power dc-ac utility interactive inverter is individually mounted on each PV module and operates so as to generate the maximum power from its corresponding PV module. Especially in the case of a single-phase utility interactive inverter, an electrolytic capacitor of large capacitance has been connected on the dc input bus in order to decouple the power pulsation caused by single-phase power generation to the utility line. However, especially during the summer season, the ac module inverters have to operate under a very high atmospheric temperature, and hence the lifetime of the inverter is shortened, because the electrolytic capacitor has a drastically shortened life when used in a high-temperature environment. Of course, we may be able to use film capacitors instead of the electrolytic capacitors if we can pay for the extreme large volume of the inverter. However, this is not a realistic solution for ac module systems. This paper proposes a novel flyback-type utility interactive inverter circuit topology suitable for ac module systems when its lifetime under high atmospheric temperature is taken into account. A most distinctive feature of the proposed system is that the decoupling of power pulsation is executed by an additional circuit that enables employment of film capacitors with small capacitance not only for the dc input line but also for the decoupling circuit, and hence the additional circuit is expected to extend the lifetime of the inverter. The proposed inverter circuit also enables realization of small volume, lightweight, and stable ac current injection into the utility line. A control method suitable for the proposed inverter is also proposed. The effectiveness of the proposed inverter is verified thorough P-SIM simulation and experiments on a 100-W prototype

Protein phosphatase 2A protects centromeric sister chromatid cohesion during meiosis I

Abstract: Segregation of homologous maternal and paternal centromeres to opposite poles during meiosis I depends on post-replicative crossing over between homologous non-sister chromatids, which creates chiasmata and therefore bivalent chromosomes. Destruction of sister chromatid cohesion along chromosome arms due to proteolytic cleavage of cohesin's Rec8 subunit by separase resolves chiasmata and thereby triggers the first meiotic division. This produces univalent chromosomes, the chromatids of which are held together by centromeric cohesin that has been protected from separase by shugoshin (Sgo1/MEI-S332) proteins. Here we show in both fission and budding yeast that Sgo1 recruits to centromeres a specific form of protein phosphatase 2A (PP2A). Its inactivation causes loss of centromeric cohesin at anaphase I and random segregation of sister centromeres at the second meiotic division. Artificial recruitment of PP2A to chromosome arms prevents Rec8 phosphorylation and hinders resolution of chiasmata. Our data are consistent with the notion that efficient cleavage of Rec8 requires phosphorylation of cohesin and that this is blocked by PP2A at meiosis I centromeres.

Solar neutrino measurements in Super-Kamiokande-II

Abstract: The results of the second phase of the Super-Kamiokande solar neutrino measurement are presented and compared to the first phase. The solar neutrino flux spectrum and time variation as well as oscillation results are statistically consistent with the first phase and do not show spectral distortion. The time-dependent flux measurement of the combined first and second phases coincides with the full period of solar cycle 23 and shows no correlation with solar activity. The measured {sup 8}B total flux is (2.38{+-}0.05(stat.){sub -0.15}{sup +0.16}(sys.))x10{sup 6} cm{sup -2} s{sup -1} and the day-night difference is found to be (-6.3{+-}4.2(stat.){+-}3.7(sys.))%. There is no evidence of systematic tendencies between the first and second phases.

Solitons in the Higgs phase: the moduli matrix approach

Abstract: We review our recent work on solitons in the Higgs phase. We use U(NC) gauge theory with NF Higgs scalar fields in the fundamental representation, which can be extended to possess eight supercharges. We propose the moduli matrix as a fundamental tool to exhaust all BPS solutions, and to characterize all possible moduli parameters. Moduli spaces of domain walls (kinks) and vortices, which are the only elementary solitons in the Higgs phase, are found in terms of the moduli matrix. Stable monopoles and instantons can exist in the Higgs phase if they are attached by vortices to form composite solitons. The moduli spaces of these composite solitons are also worked out in terms of the moduli matrix. Webs of walls can also be formed with characteristic difference between Abelian and non-Abelian gauge theories. Instanton–vortex systems, monopole–vortex–wall systems, and webs of walls in Abelian gauge theories are found to admit negative energy objects with the instanton charge (called intersectons), the monopole charge (called boojums) and the Hitchin charge, respectively. We characterize the total moduli space of these elementary as well as composite solitons. In particular the total moduli space of walls is given by the complex Grassmann manifold SU(NF)/[SU(NC) × SU(NF − NC) × U(1)] and is decomposed into various topological sectors corresponding to boundary condition specified by particular vacua. The moduli space of k vortices is also completely determined and is reformulated as the half ADHM construction. Effective Lagrangians are constructed on walls and vortices in a compact form. We also present several new results on interactions of various solitons, such as monopoles, vortices and walls. Review parts contain our works on domain walls (Isozumi Y et al 2004 Phys. Rev. Lett. 93 161601 (Preprint hep-th/0404198), Isozumi Y et al 2004 Phys. Rev. D 70 125014 (Preprint hep-th/0405194), Eto M et al 2005 Phys. Rev. D 71 125006 (Preprint hep-th/0412024), Eto M et al 2005 Phys. Rev. D 71 105009 (Preprint hep-th/0503033), Sakai N and Yang Y 2005 Comm. Math. Phys. (in press) (Preprint hep-th/0505136)), vortices (Eto M et al 2005 Phys. Rev. Lett. 96 161601 (Preprint hep-th/0511088), Eto M et al 2006 Phys. Rev. D 73 085008 (Preprint hep-th/0601181)), domain wall webs (Eto M et al 2005 Phys. Rev. D 72 085004 (Preprint hep-th/0506135), Eto M et al 2006 Phys. Lett. B 632 384 (Preprint hep-th/0508241), Eto M et al 2005 AIP Conf. Proc. 805 354 (Preprint hep-th/0509127)), monopole–vortex–wall systems (Isozumi Y et al 2005 Phys. Rev. D 71 065018 (Preprint hep-th/0405129), Sakai N and Tong D 2005 J. High Energy Phys. JHEP03(2005)019 (Preprint hep-th/0501207)), instanton–vortex systems (Eto M et al 2005 Phys. Rev. D 72 025011 (Preprint hep-th/0412048)), effective Lagrangian on walls and vortices (Eto M et al 2006 Phys. Rev. D (in press) (Preprint hep-th/0602289)), classification of BPS equations (Eto M et al 2005 Preprint hep-th/0506257) and Skyrmions (Eto M et al 2005 Phys. Rev. Lett. 95 252003 (Preprint hep-th/0508130)).

Evidence from fluid inclusions for microbial methanogenesis in the early Archaean era

Abstract: Methanogenic microbes may be one of the most primitive organisms, although it is uncertain when methanogens first appeared on Earth. During the Archaean era (before 2.5 Gyr ago), methanogens may have been important in regulating climate, because they could have provided sufficient amounts of the greenhouse gas methane to mitigate a severely frozen condition that could have resulted from lower solar luminosity during these times. Nevertheless, no direct geological evidence has hitherto been available in support of the existence of methanogens in the Archaean period, although circumstantial evidence is available in the form of approximately 2.8-Gyr-old carbon-isotope-depleted kerogen. Here we report crushing extraction and carbon isotope analysis of methane-bearing fluid inclusions in approximately 3.5-Gyr-old hydrothermal precipitates from Pilbara craton, Australia. Our results indicate that the extracted fluids contain microbial methane with carbon isotopic compositions of less than -56 per thousand included within original precipitates. This provides the oldest evidence of methanogen (> 3.46 Gyr ago), pre-dating previous geochemical evidence by about 700 million years.

Recent Advances of VCSEL Photonics

Abstract: A vertical-cavity surface emitting laser (VCSEL) was invented 30 years ago. A lot of unique features can be expected, such as low-power consumption, wafer-level testing, small packaging capability, and so on. The market of VCSELs has been growing up rapidly in recent years, and they are now key devices in local area networks using multimode optical fibers. Also, long wavelength VCSELs are currently attracting much interest for use in single-mode fiber metropolitan area and wide area network applications. In addition, a VCSEL-based disruptive technology enables various consumer applications such as a laser mouse and laser printers. In this paper, the recent advance of VCSEL photonics will be reviewed, which include the wavelength extension of single-mode VCSELs and their wavelength integration/control. Also, this paper explores the potential and challenges for new functions of VCSELs toward optical signal processing

Periodic arrangement of silica nanospheres assisted by amino acids.

Abstract: Uniform-sized silica nanospheres with a well-ordered arrangement were successfully synthesized by a novel and simple method; hydrolysis and condensation reactions oftetraethyl orthosilicate were conducted in the presence of basic amino acids.

MARCH‐V is a novel mitofusin 2‐ and Drp1‐binding protein able to change mitochondrial morphology

Abstract: Mitofusins and Drp1 are key components in mitochondrial membrane fusion and division, but the molecular mechanism underlying the regulation of their activities remains to be clarified. Here, we identified human membrane-associated RING-CH (MARCH)-V as a novel transmembrane protein of the mitochondrial outer membrane. Immunoprecipitation studies demonstrated that MARCH-V interacts with mitofusin 2 (MFN2) and ubiquitinated forms of Drp1. Overexpression of MARCH-V promoted the formation of long tubular mitochondria in a manner that depends on MFN2 activity. By contrast, mutations in the RING finger caused fragmentation of mitochondria. We also show that MARCH-V promotes ubiquitination of Drp1. These results indicate that MARCH-V has a crucial role in the control of mitochondrial morphology by regulating MFN2 and Drp1 activities.

Local Fisher discriminant analysis for supervised dimensionality reduction

Abstract: Dimensionality reduction is one of the important preprocessing steps in high-dimensional data analysis. In this paper, we consider the supervised dimensionality reduction problem where samples are accompanied with class labels. Traditional Fisher discriminant analysis is a popular and powerful method for this purpose. However, it tends to give undesired results if samples in some class form several separate clusters, i.e., multimodal. In this paper, we propose a new dimensionality reduction method called local Fisher discriminant analysis (LFDA), which is a localized variant of Fisher discriminant analysis. LFDA takes local structure of the data into account so the multimodal data can be embedded appropriately. We also show that LFDA can be extended to non-linear dimensionality reduction scenarios by the kernel trick.

Edge state on hydrogen-terminated graphite edges investigated by scanning tunneling microscopy

Abstract: The edge states that emerge at hydrogen-terminated zigzag edges embedded in dominant armchair edges of graphite are carefully investigated by ultrahigh-vacuum scanning tunneling microscopy (STM) measurements. The edge states at the zigzag edges have different spatial distributions dependent on the $\ensuremath{\alpha}$- or $\ensuremath{\beta}$-site edge carbon atoms. In the case that the defects consist of a short zigzag (or a short Klein) edge, the edge state is present also near the defects. The amplitude of the edge state distributing around the defects in an armchair edge often has a prominent hump in a direction determined by detailed local atomic structure of the edge. The tight binding calculation based on the atomic arrangements observed by STM reproduces the observed spatial distributions of the local density of states.

Weak Convergence Theorem by an Extragradient Method for Nonexpansive Mappings and Monotone Mappings

Abstract: In this paper, we introduce an iterative process for finding the common element of the set of fixed points of a nonexpansive mapping and the set of solutions of the variational inequality problem for a monotone, Lipschitz-continuous mapping. The iterative process is based on the so-called extragradient method. We obtain a weak convergence theorem for two sequences generated by this process

Multiple Label-Free Detection of Antigen−Antibody Reaction Using Localized Surface Plasmon Resonance-Based Core−Shell Structured Nanoparticle Layer Nanochip

Abstract: In this research, a localized surface plasmon resonance (LSPR)-based bioanalysis method for developing multiarray optical nanochip suitable for screening bimolecular interactions is described. LSPR-based label-free monitoring enables to solve the problems of conventional methods that require large sample volumes and time-consuming labeling procedures. We developed a multiarray LSPR-based nanochip for the label-free detection of proteins. The multiarray format was constructed by a core-shell-structured nanoparticle layer, which provided 300 nanospots on the sensing surface. Antibodies were immobilized onto the nanospots using their interaction with Protein A. The concentrations of antigens were determined from the peak absorption intensity of the LSPR spectra. We demonstrated the capability of the array measurement using immunoglobulins (IgA, IgD, IgG, IgM), C-reactive protein, and fibrinogen. The detection limit of our label-free method was 100 pg/mL. Our nanochip is readily transferable to monitor the interactions of other biomolecules, such as whole cells or receptors, with a massively parallel detection capability in a highly miniaturized package. We anticipate that the direct label-free optical immunoassay of proteins reported here will revolutionize clinical diagnosis and accelerate the development of hand-held and user-friendly point-of-care devices.

Development and characterization of Ni-free Ti-base shape memory and superelastic alloys

Abstract: Recently the Ni-hypersensitivity and toxicity of Ni have stimulated the development of Ni-free shape memory alloys. The β-Ti alloys are the most attractive candidates for biomedical shape memory alloys. Ti–Nb–X (X = Zr, Ta, Mo, Au, Pd, Pt, Al, Ga, Ge, O) and Ti–Mo–X (X = Ta, Nb, Zr, Au, Pd, Pt, Al, Ga, Ge) alloys have been developed and their shape memory effect and superelasticity were investigated systematically by the present authors for about 5 years. Although shape memory effect and superelasticity observed in the Ti–Nb alloys, the low critical stress for slip deformation caused the superelasticity not to reveal a large strain at room temperature. However, low temperature annealing and an aging treatment were effective in improving superelasticity. Additions of alloying elements such as Zr, Ta, Mo, Au, Pt and Al were also effective in stabilizing the superelasticity. In this paper, the basic characteristics of Ti–Nb, Ti–Nb–Zr, Ti–Nb–Ta and Ti–Nb–O are to be briefly reviewed based on the recent works of the present authors.

The Japanese space gravitational wave antenna?DECIGO

Abstract: DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. It aims at detecting various kinds of gravitational waves between 1 mHz and 100 Hz frequently enough to open a new window of observation for gravitational wave astronomy. The pre-conceptual design of DECIGO consists of three drag-free satellites, 1000 km apart from each other, whose relative displacements are measured by a Fabry–Perot Michelson interferometer. We plan to launch DECIGO in 2024 after a long and intense development phase, including two pathfinder missions for verification of required technologies.