A5100724342- Astro and Planetary Science
- Planetary Science and Exploration
- Silicon and Solar Cell Technologies
- Lightning and Electromagnetic Phenomena
- Spacecraft and Cryogenic Technologies
- Thin-Film Transistor Technologies
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Isotope Analysis in Ecology
- Geomagnetism and Paleomagnetism Studies
- Silicon Nanostructures and Photoluminescence
- Electrocatalysts for Energy Conversion
- Ionosphere and magnetosphere dynamics
- Gamma-ray bursts and supernovae
- Nuclear Physics and Applications
- Spacecraft Dynamics and Control
- Experimental and Theoretical Physics Studies
- Space Satellite Systems and Control
- Stellar, planetary, and galactic studies
- Earthquake Detection and Analysis
- Nuts composition and effects
- High-pressure geophysics and materials
- Pulsars and Gravitational Waves Research
- solar cell performance optimization
- Atomic and Subatomic Physics Research
Yamaha (Japan)
2025
Tokyo-Kita Medical Center
2022
Jet Propulsion Laboratory
2014-2021
Kyoto University
2017
Kyushu Institute of Technology
2017
Kyoto Institute of Technology
2016
University of Colorado Boulder
2010-2015
Tohoku University
1997-2014
Japan Aerospace Exploration Agency
2014
University of Colorado System
2010-2014
Photographic surveying of the minority carrier diffusion length distribution in polycrystalline silicon solar cells was proposed. Light emission from cell under forward bias captured by a charge coupled device camera. We have found that intensity light clearly agreed with mapping active layers. The had one-to-one relationship length, which yielded semiquantitative analysis method and detection deteriorated areas.
Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances particle ejection from the surface (101955) Bennu, demonstrating it is an active asteroid. The events were imaged by OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For three largest observed events, we estimated ejected velocities sizes, event times, source regions, energies. also determined trajectories photometric properties...
The electroluminescence intensity from Si cells under the forward bias was found to have one quantitative agreement with minority carrier diffusion length. Based on equation and simple p-n diode model, analyzed relative cell performance. Electroluminescence is proportional product of injected density effective ideality factor n can be deduced by measuring as a function injection current. Among various crystalline silicon including single polycrystalline types, measured at fixed current has...
The characteristics of the interior gravity field are derived, summarized, and evaluated near surface an asteroid for purpose small body proximity operations. In order to characterize a body, exterior is widely in use. However, expression breaks down when computing potential its gradients within Brillouin sphere, meaning that spacecraft dynamics cannot be modeled accurately close body's surface. On other hand, convergence guaranteed sphere potential, feature enables modeling body. After...
The gravity field of a small body provides insight into its internal mass distribution. We used two approaches to measure the rubble-pile asteroid (101955) Bennu: (i) tracking and modeling spacecraft in orbit about (ii) pebble-sized particles naturally ejected from Bennu's surface sustained orbits. These yield statistically consistent results up degree order 3, with particle-based being significant 9. Comparisons constant-density shape model show that Bennu has heterogeneous deviations can...
Abstract We analyze the trajectories of 313 particles seen in near‐Bennu environment between December 2018 and September 2019. Of these, 65% follow suborbital trajectories, 20% undergo more than one orbital revolution around asteroid, 15% directly escape on hyperbolic trajectories. The median lifetime these is ∼6 hr. are sensitive to Bennu's gravitational field, which allows us reliably estimate spherical harmonic coefficients through degree 8 resolve nonuniform mass distribution 3....
Small bodies such as the near-Earth asteroid Bennu drift in their orbit due to thermal radiation forces (the Yarkovsky effect). Ground-based observations have indicated a nonzero probability of impacting Earth, depending on how its evolves. Thus, among goals OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission were precisely measure effect refine impact hazard assessment for this body. Here we address these objectives. Using...
The Imager of Sprites and Upper Atmospheric Lightning (ISUAL) experiment on the FORMOSAT-2 satellite has recently reported that an elve is most dominant type transient luminous events (TLEs) deduced global occurrence rates sprites, halos elves to be ∼1, ∼1 35 events/min, respectively (Chen et al 2008 J. Geophys. Res. 113 A08306). In this paper, we report computed radiative emission energy precipitation TLEs in upper atmosphere. By analysing 1415 ISUAL TLEs, found for spatially averaged...
The 4.5 km long near-Earth asteroid 4179 Toutatis has made close Earth flybys approximately every four years between 1992 and 2012, been observed with high-resolution radar imaging during each approach. Its most recent flyby in 2012 December was extensively at the Goldstone Very Large Array telescopes. In this paper, Toutatis' spin state dynamics are estimated from observations of five 2008. Observations were used to fit a least-squares sense, solar terrestrial tidal torques incorporated...
Abstract In early 2019, the OSIRIS‐REx spacecraft discovered small particles being ejected from surface of near‐Earth asteroid Bennu.sww Although they were seen to be at slow speeds, on order tens cm/s, a number surprisingly orbit for multiple revolutions and days, which requires dynamical mechanism quickly substantially modify prevent re‐impact upon their first periapse passage. This paper demonstrates that, based simulations constrained by conditions observed events, combined effects...
We investigated electrochemical properties for the Pt–Au bimetallic surfaces prepared by 0.3-nm-thick Pt depositions on Au(111), (110), and (100) substrates (Pt0.3nm/Au(hkl)) molecular beam epitaxy. The Pt0.3nm/Au(111) surface at substrate temperature of 300 K (300K–Pt0.3nm/Au(111)) showed a corrugated Pt(111) epitaxial which 3–5 nm size monoatomic height islands are located. Oxygen reduction reaction (ORR) activity was enhanced factor ca. 2 relative to that clean surface. In contrast,...
The laser-doping technique in silicon solar cell fabrication is now attracting considerable attention because of its suitability for the low-cost processing high-efficiency cells; it can be performed at room temperature air and intricate doping areas formed easily. In this study, we used a laser with UV wavelength (355 nm) instead conventionally 532 nm to form property-controlled regions emitter or back surface field (BSF) cells air. depth phosphorus boron was precisely controlled shallow...
DOI: 10.2514/1.53722 The most crucial task for a spacecraft upon arriving at small body is to determine the strength of body's gravity field. This research proposes and models this initial characterization via series slow flybys analyzes how rapidly field can be estimated precision which it determined. Two analytical issues areaddressedinthispaperthatarepertinenttothedesignofthischaracterizationprocessandcanbeusedtoevaluate whether thereis aneed lidarmeasurements. A new operational procedure...
Optical and search coil magnetometer data obtained from the SPRITES'96 campaign carried out at Yucca Ridge Field Station, Colorado in July 1996 have presented clear evidence for excitation of ULF transients with their dominant power 1–2 Hz by strong lightning discharges producing elves sprites. The most striking feature is that exhibit different wave forms case sprites without preceding elves. In former damped, quasi‐sinusoidal oscillations commence impulsively onset sprites, while latter...
The National Institute of Information and Communications Technology (NICT) has developed tested carrier-phase two-way satellite time frequency transfer (TWSTFT) as a next-generation technique applicable to greater distances resulting in higher precision. A method different from that used for code-based TWSTFT is required TWSTFT. We propose new based on variations carrier phases the propagation signals.
The effect of passivation layers (SiOX, SiNX, etc.) using plasma-enhanced chemical vapor deposition (PECVD) for crystalline silicon solar cells showed high surface recombination with decreasing temperature (<300 °C). Czochralski (Cz) monocrystalline (c-Si) wafer was exposed to an NH3 plasma before the low-temperature nitride (SiNX) layer or amorphous (a-Si:H) in a system respectively. treatment interface observed by microwave photoconductance decay (µ-PCD), quasi-steady-state (QSSPC),...