A5101487275- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Cold Atom Physics and Bose-Einstein Condensates
- Soil and Unsaturated Flow
- Atomic and Subatomic Physics Research
- Advanced Chemical Physics Studies
- Laser Design and Applications
- Vehicle emissions and performance
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Quantum Information and Cryptography
- Radioactive element chemistry and processing
- Radioactive contamination and transfer
- Soil Moisture and Remote Sensing
- Isotope Analysis in Ecology
- Electron and X-Ray Spectroscopy Techniques
- Climate change and permafrost
- Spectroscopy and Laser Applications
- Advanced Frequency and Time Standards
- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Analytical chemistry methods development
- Quantum optics and atomic interactions
Center for Environmental Science in Saitama
2010-2025
The University of Tokyo
2015-2024
National Institute for Environmental Studies
2003-2020
Japan Atomic Energy Agency
2020
Institute for Laser Technology
2020
Kagawa University
2019
Nagaoka University
2018
Nagaoka University of Technology
2018
Tokai University
2017
Hokkaido University
1996-2013
A dramatic reduction in soil frost depth has been reported for Hokkaido Island of northern Japan over the last 20 years. Since strongly affects snowmelt infiltration and runoff, may have altered water nutrient cycles this region. paired‐plot experiment was conducted an agricultural field Tokachi, Hokkaido, to compare movement at different depths, controlled by manipulating snow cover. Snow removed enhance freezing treatment plot undisturbed control plot. The froze a maximum 0.43 m under 0.11...
Numerous new resonances of triply photoexcited hollow Li atoms have been found above the ${2s}^{2}2p{}^{2}{P}^{o}$ resonance at 142.3 eV. The main features are reproduced by multiconfiguration Dirac-Fock calculations. spectrum lacks regular series structure and pattern is to manifest effect atomic nature excited states. Fano parameters for were obtained. One-step double autoionization was observed first time in decay from this resonance.
The recent Nuclear Regulation Authority evaluation report suggests that at the Fukushima Daiichi Power Station, concrete shield plugs above primary containment vessel (PCV) have exceptionally high radiation levels in Units 2 and 3, which may increase risk of exposure during decommissioning operations. During cleaning disassembly such hot spots, it is expected a large amount submicron-sized radioactive aerosol particles will be generated, influence operation. In present study, laser...
Changes in the concentrations and fluxes of CO2 were monitored to a depth 100 cm an Andisol, under both fallow soybean crops for period 1 year. Gas flux was calculated by diffusion equation. Diel at depths less than 40 followed sinusoidal pattern similar that soil temperature, with highest value being recorded daytime. Heavy rainfall, which closed air pathways atmosphere, resulted higher concentration shallow layers. The subsequent decrease layers accompanied increase few days deeper...
Long-term exposure to fine particulate matter (PM2.5) is causally associated with mortality and cardiovascular disease. However, in terms of cause-specific outcomes, there are fewer studies about stroke than coronary heart disease, particularly Asia. Furthermore, remains uncertainty regarding the PM2.5-respiratory disease association. We examined whether long-term PM2.5 all-cause, respiratory Japan. used data 46,974 participants (19,707 men; 27,267 women), who were enrolled 2009 followed up...
The radiocarbon ((14)C) of total carbon (TC) in atmospheric fine particles was measured at 6 h or 12 intervals two sites, 50 and 100 km downwind from Tokyo, Japan (Kisai Maebashi) summer 2007. percent modern (pMC) showed clear diurnal variations with minimums the daytime. mean pMC values Maebashi were 28 ± 7 daytime 45 16 night (37 15 for overall period). Those Kisai 26 9 44 8 This data indicates that fossil sources major contributors to TC, while had comparable contributions nighttime TC...
The number concentration and size distributions of ultrafine particles were measured with a Scanning Mobility Particle Sizer (SMPS) at roadside in early autumn winter, the results are discussed regard to contribution traffic activity meteorological conditions. <50 nm fraction increased morning under calm wind conditions, this increase corresponded total volume nitric oxide. was influenced not only by but also high diesel engine vehicles. decreased around noon as speed increased, although...
Abstract Determination of the gas diffusion coefficient D s peat soils is essential to understand mechanisms soil transport in peatlands, which have been one major potential sources gaseous carbons. In present study, we aimed at determining for various values air-filled porosity a and tested validity Three-Porosity Model (Moldrup et al. 2004) Millington-Quirk model (1961) predicting relative diffusivity, ratio 0, free air. Undisturbed cores were sampled from aerobic layers Bibai mire,...
Abstract Despite the potential impact of winter soil water movements in cold regions, relatively few field studies have investigated cold‐season hydrological processes that occur before spring‐onset snowmelt infiltration. The contribution fluxes to annual balance was evaluated over 5 years observations at an agricultural Tokachi, Hokkaido, Japan. In two winters, frost reached a maximum depth 0·2 m (‘frozen’ winters), whereas mostly absent during remaining three winters (‘unfrozen’ winters)....
Abstract A dryland rice variety, OS4, was grown in the field during dry season to study evapotranspiration, root distribution, and water extraction patterns by roots after irrigation discontinued. Roorts were observed up 80 cm, 90% of total length distributed within top 50 cm. The high density surface layer is a characteristic system. Potential evapotranspiration continued for 6 days field. Soil potentials on sixth day about -10 bar 10-15 cm soil -0.7 40-50 layer. When whole profile wet,...
Experimental approaches for directly determining preferential water flow in field soils usually require artificial interruption of the soil matrix's flow. This may change quantitative as well qualitative nature flow, particularly such Andisols where matrix is dominant process drainage. To overcome this problem, we applied both one‐dimensional form Darcy's equation and balance method, during shortly after each rain event, characterizing across a depth 1 m an Andisol. The volumetric contents...