Takehiko Ishikawa
A5022339252- Solidification and crystal growth phenomena
- Metallurgical Processes and Thermodynamics
- Magnetic and Electromagnetic Effects
- nanoparticles nucleation surface interactions
- Material Dynamics and Properties
- Electrohydrodynamics and Fluid Dynamics
- Metallic Glasses and Amorphous Alloys
- Glass properties and applications
- Aluminum Alloy Microstructure Properties
- Metallurgical and Alloy Processes
- Pulsars and Gravitational Waves Research
- Ferroelectric and Piezoelectric Materials
- Crystallization and Solubility Studies
- Planetary Science and Exploration
- Radio Astronomy Observations and Technology
- Microfluidic and Bio-sensing Technologies
- Spacecraft and Cryogenic Technologies
- Freezing and Crystallization Processes
- High-pressure geophysics and materials
- Multiferroics and related materials
- Acoustic Wave Resonator Technologies
- Theoretical and Computational Physics
- Iron and Steelmaking Processes
- Concrete and Cement Materials Research
- Calibration and Measurement Techniques
Institute of Space and Astronautical Science
2013-2024
Japan Aerospace Exploration Agency
2015-2024
The Graduate University for Advanced Studies, SOKENDAI
2014-2024
Advanced Engineering Services (Japan)
2015
Shizuoka University
2015
SPring-8
2012
Asahi Kasei (Japan)
2008-2011
Osaka University
2008
Chiba Institute of Technology
2005
Toshiba (Japan)
2004
The objectives of the DECi-hertz Interferometer Gravitational Wave Observatory (DECIGO) are to open a new window observation for gravitational wave astronomy and obtain insight into significant areas science, such as verifying characterizing inflation, determining thermal history universe, dark energy, describing formation mechanism supermassive black holes in center galaxies, testing alternative theories gravity, seeking hole matter, understanding physics neutron stars searching planets...
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational antenna. It aims at detecting various kinds of waves between 1 mHz and 100 Hz frequently enough to open a new window observation for astronomy. The pre-conceptual design DECIGO consists three drag-free satellites, 1000 km apart from each other, whose relative displacements are measured by Fabry–Perot Michelson interferometer. We plan launch in 2024 after long intense development...
DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) is the planned Japanese space gravitational antenna, aiming to detect waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz 10 thus open a new window for astronomy universe. will consists of three drag-free spacecraft arranged in an equilateral triangle with 1000 km arm lengths whose relative displacements are measured by differential Fabry-Perot interferometer, four units triangular...
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational antenna. DECIGO expected to open a new window of observation for astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries universe such as dark energy, formation mechanism supermassive black holes, inflation universe. The pre-conceptual design consists three drag-free spacecraft, whose relative displacements are measured by differential Fabry-Perot Michelson...
Bioinspired ceramics with micron-scale ceramic "bricks" bonded by a metallic "mortar" are projected to result in higher strength and toughness ceramics, but their processing is challenging as metals do not typically wet ceramics. To resolve this issue, we made alumina structures using rapid pressureless infiltration of zirconium-based bulk-metallic glass mortar that reactively wets the surface freeze-cast preforms. The mechanical properties resulting Al2O3 glass-forming compliant-phase...
DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO) is a future Japanese space gravitational-wave antenna. The most important objective of DECIGO, among various sciences to be aimed at, detect gravitational waves coming from the inflation universe. DECIGO consists four clusters spacecraft, and each cluster three spacecraft with Fabry–Perot Michelson interferometers. As pathfinder mission B-DECIGO will launched, hopefully in 2020s, demonstrate technologies necessary for as well...
Abstract The structure of high-temperature liquids is an important topic for understanding the fragility liquids. Here we report a non-glass-forming oxide liquid, ZrO 2 , at atomistic and electronic level. Bhatia–Thornton number–number factor does not show first sharp diffraction peak. atomic comprises 5 6 7 polyhedra with significant contribution edge sharing oxygen in addition to corner sharing. variety large coordination polyhedral connections short Zr–O bond lifetimes, induced by...
Two new methods that substantially ease the processing and study of refractory metals, when an electrostatic levitation furnace is used, are reported. The first technique concerned with preheating sample on a pedestal, prior to launch, temperature (∼1500 K) at which thermionic emission dominates all other charging/discharging mechanisms may be going simultaneously. Launched into temperature, can quickly heated its molten state without encountering further charge loss problems. This procedure...
The electrostatic levitation system, including its history and development, techniques for non-contact thermophysical property measurements (density, ratio of isobaric heat capacity to hemispherical total emissivity, surface tension viscosity) are reviewed. Thermophysical properties refractory metals whose melting temperatures over 2000 K have been measured with an levitator. experimental results vanadium, zirconium, niobium, molybdenum, rhodium, ruthenium, iridium, tantalum rhenium...
Metallic liquid silicon at 1787K is investigated using x-ray Compton scattering. An excellent agreement found between the measurements and corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in provide support for occurrence theoretically predicted liquid-liquid phase transition supercooled states. The population bond pairs estimated to be 17% via a maximally-localized Wannier function analysis. scattering shown sensitive probe effects state.
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational antenna. The goal of DECIGO to detect waves from various kinds sources mainly between 0.1 Hz and 10 thus open a new window observation for astronomy. will consist three drag-free spacecraft, 1000 km apart each other, whose relative displacements are measured by Fabry—Perot Michelson interferometer. We plan launch pathfinder first demonstrate technologies required realize and, if...
A noncontact technique of measuring the changes in electrical conductivity (or resistivity) conducting liquids is reported. The based on a drop that levitated by high-temperature electrostatic levitator high vacuum. This technique, which utilizes principle asynchronous induction motor, measures relative torque as function temperature applying rotating magnetic field to sample. Changes resistivity are related measured using formula developed for motor. Validity this was demonstrated pure...
Thermophysical properties of molten refractory metals (titanium, zirconium, hafnium, and niobium) have been measured using a containerless method. Using an in-house developed electrostatic levitator, the density, heat capacity, entropy, surface tension, viscosity liquid phases over wide temperature range. The data showed good agreement with theoretical calculations based on hard sphere model.
The density and the isobaric heat capacity of alumina in its liquid undercooled states were measured using an electrostatic levitation furnace. Over 2175 to 2435 K temperature interval, can be expressed as ρ( T )=2.93×10 3 -0.12( - m ) (kg·m -3 with =2327 K, yielding a volume expansion coefficient α( )=4.1×10 -5 (K -1 ). In addition, estimated C P ( )=153.5+3.1×10 (J·mol ·K if hemispherical total emissivity remains constant at 0.8 over 2120 2450 interval. enthalpy entropy fusion have also...
Oxygen-deficient h-BaTiO3 synthesized by noncontact processing exhibits a dielectric constant higher than 100 000 with loss component of about 0.1 together weak temperature dependence in the range to 300 K. Dielectric dramatically dropped 2 orders magnitude below 70
A space gravitational-wave antenna, DECIGO (DECI-hertz interferometer Gravitational wave Observatory), will provide fruitful insights into the universe, particularly on formation mechanism of supermassive black holes, dark energy and inflation universe. In current pre-conceptual design, be comprising four units; each unit formed by three drag-free spacecraft with 1000 km separation. Since an extremely challenging mission high-precision flight long baseline, it is important to increase...
Abstract Understanding the liquid structure provides information that is crucial to uncovering nature of glass-liquid transition. We apply an aerodynamic levitation technique and high-energy X-rays ( l )-Er 2 O 3 discover its structure. The sample densities are measured by electrostatic at International Space Station. Liquid Er displays a very sharp diffraction peak (principal peak). Applying combined reverse Monte Carlo – molecular dynamics approach, simulations produce Er–O coordination...
Three dielectric relaxations in hexagonal (h)-BaTiO3 single crystals exhibiting giant permittivity were detected a frequency range of 100Hz–3GHz and analyzed by an equivalent circuit with three parallel RC elements. A best-fit result indicated that the responses bulk crystal capacitance 1pF, interfacial layer 1.4nF, depletion 1nF. We confirmed exceeding 105 could be achieved h-BaTiO3 crystal. In addition, Schottky barrier height at contacting interface between Cu electrodes surface was...