Yutaka Matsumi

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Papers

Citation

H-Index

i-10 index

Research Field

Photodissociation of Trimethylindium and Trimethylgallium on GaAs at 193 nm Studied by Angle-Resolved Photoelectron Spectroscopy

Japanese Journal of Applied Physics (1993)

Satoshi Shogen Masafumi Ohashi Satoshi Hashimoto Yutaka Matsumi Masahiro Kawasaki

The chemisorption and photodecomposition of trimethylindium (TMIn) and trimethylgallium (TMGa) on a GaAs(100) surface have been studied by means of angle-resolved X-ray and ultraviolet photoelectron spectroscopy. Increase in the substrate temperature from 150 to 300 K causes the In-C bond cleavage of the adsorbed TMIn to generate methyl radicals that react with Ga species in the substrate to form Ga-C bonds. The 193 nm irradiation of TMIn adsorbed on GaAs at 150 K induces the In-C bond cleavage. The carbon species desorb from the substrate. Irradiation at 351 nm causes no change in the X-ray photoelectron spectra of the adsorbed species. These results imply that photodissociation is not due to photoabsorption of the GaAs substrate but that of the adsorbed species on the substrate. Photoirradiation of 488 nm on TMIn adsorbed on GaAs at 150 K induces pyrolytic cleavage of the In-C bond.

Trimethylgallium

Trimethylindium

Chemisorption

Bond cleavage

10.1143/jjap.32.3099

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Citations (3)

APPLICABILITY OF MANEGEMENT SYSTEM ON SCHEME OF DUMPING BLOCKS FROM BARGE IN CONSTRUTING ARTIFICIAL FISHING MOUND

Journal of Japan Society of Civil Engineers Ser B3 (Ocean Engineering) (2011)

Yutaka Matsumi Toshio Aono K. Osada Tomoyuki Katayama Youhei Hara

人工海底山脈は,深層水の富栄養塩水塊の湧昇流効果による生産性の高い漁場造成を目的に,土運船を用いて大量な石材投入によって築造される.従って,効率的な施工には投入前の堆積形状予測と投入座標算出,投入時の流れによる投入材の移動変位を考慮した投入位置管理が要求される.著者らの堆積形状予測モデルは,現場での堆積形状に関する実測結果と概ね一致するが,人工海底山脈の最終施工段階における斜面部の造築の際に,予測結果の斜面勾配がたち過ぎる傾向にある.本研究は,まず堆積形状予測モデルにおける多点多数回投入時の堆積斜面勾配が投入石材の安息勾配以上になる問題を改良し,ついで,これまでの石材による人工海底山脈の施工を対象に,著者らの石材投入工法管理システムの現地適用性を検証したものである.

BARGE

Dumping

10.2208/jscejoe.67.i_445

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Citations (0)

GENERATION OF LOW FREQUENCY WAVES ON A STEP CONFIGURATION

Coastal Engineering 1984 (2003)

Akira Kimura Yutaka Matsumi Kenichi Ohno

10.1142/9789812791306_0095

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Citations (0)

Kinetics of the reactions of () and () atoms with C3H8,C3D8, n-C4H10, and i-C4H10 at 298 K

Chemical Physics Letters (2001)

Kanami Hitsuda Kenshi Takahashi Yutaka Matsumi Timothy J. Wallington

Flash photolysis

Reaction rate

10.1016/s0009-2614(01)00947-2

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Citations (15)

Relationship between the concentration of fine particulate matter and aerosol optical depth in the Middle Urals

27th International Symposium on Atmospheric and Ocean Optics, Atmospheric Physics (2021)

A. P. Luzhetskaya E. S. Nagovitsyna Elena V. Omelkova Vasiliy A. Poddubny Alexey A. Shchelkanov

The article is concerned with statistical analysis of the relationship between the ground level fine aerosol concentrations and the aerosol optical depth of the atmosphere. The aerosol characteristics measurements at two monitoring sites in the Middle Urals (Yekaterinburg city and the background region) combined with meteorological parameters and vegetation indices were used. Several linear models to estimate fine particulate matter concentrations using aerosol optical depth measurements and meteorological parameters are presented.

Atmospheric models

Atmospheric correction

Atmospheric optics

Optical depth

10.1117/12.2603473

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Citations (1)

Measurements of Ammonium and Sodium salt Aerosol Particles Using a Laser-ionization Single-particle Aerosol Mass Spectrometer

Chemistry Letters (2007)

Masahiro Narukawa Yutaka Matsumi Kenshi Takahashi Akihiro Yabushita

Abstract Using a laser-ionization single-particle aerosol mass spectrometer (LISPA-MS), mass spectra of ammonium and sodium salt particles were obtained. In the negative-ion mass spectra, HSO4−, and NO2− and NO3− were dominant ions for (NH4)2SO4 and NH4NO3 particles, respectively, while ions with sodium were also dominant for Na2SO4 and NaNO3 particles. The chemical compositions of such salt aerosol particles can be inferred from the distribution of ions in those negative-ion mass spectra obtained using the LISPA-MS.

Particle (ecology)

Ammonium sulfate

10.1246/cl.2007.904

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Citations (8)

PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN (2005)

Yutaka Matsumi Keiichi Sumiya Takeo Asanuma

The artificial fishing mound (AFM) is constructed in deepwater by dumping a large amount of rubble or concrete blocks from a hopper barge to expand the fishing ground by uplifting the eutrophied water with the upwelling current generated on mound. In order to produce a designed geometry of AFM accurately and effectively, the operation management for the discharge position of barge, which is taken the transfer displacement of the falling blocks by the current into consideration, is required. In this study, the numerical simulation model to estimate the spatial deposition configuration of blocks dumped from barges has been expanded for the current field, and its practical adaptability has been verified by the field experiments. Furthermore, the management system on positioning of the barge, which is correspondent to the real-time utilization in the field, is developed by linking this simulation model and the inputoutput divisions for the ADCP measured data, the simulated shape of AFM and the position of barge.

BARGE

Rubble

Position (finance)

10.2208/prooe.21.343

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Developing an insulation box with automatic temperature control for PM2.5 measurements in cold regions

Journal of Environmental Management (2022)

Teppei J. Yasunari Shigeto Wakabayashi Yutaka Matsumi Sumito Matoba

Low-cost PM

Cold climate

Warm front

10.1016/j.jenvman.2022.114784

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Citations (7)

PREDICTION MODEL FOR CHANGE IN PERFORMANCE OF RUBBLE MOUND REVETMENT UNDER DAMAGE PROGRESSION

Coastal Engineering Proceedings (2014)

Takao OTA Yutaka Matsumi Hiroyuki Kawamura Kenichi Ohno

In this study, the change characteristics of wave dissipation performance of rubble mound revetment under the damage progression of armor layer are investigated using a numerical wave flume and a series of model profiles for damaged armor layer. The reflection coefficient and wave overtopping rate are used as the performance measures. A number of irregular waves with different wave profiles and wave grouping properties are generated in the numerical wave flume to obtain many data of the performance measures. Secondly, an artificial neural network (ANN) model is applied to predict the change of the performance measures with the cumulative damage of armor layer. The three - layered neural network calibrated by the results of the numerical experiments can predict the reflection coefficient with sufficient accuracy and the overtopping rate reasonably well.

Revetment

Rubble

Flume

Wave flume

Breakwater

Armour

Reflection

Reflection coefficient

Wave height

10.9753/icce.v34.structures.63

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Citations (1)

Assessment of the Sphericity of Submicrometer Particles Using a Single-particle Polar Nephelometer at an Urban Site in Japan

Aerosol and Air Quality Research (2020)

Maho Nakagawa Tomoki Nakayama Hiroshi Sasago Yuki Kuruma Hikari Yai

The sphericity of particles must be considered when evaluating their effects on the climate and human health. Thus, to examine this property and its controlling factors, this study measured the scattering angular distributions of both thermodenuded and non-thermodenuded individual particles with a diameter of 500 nm in real time using a home-made polar nephelometer in Nagoya, Japan. Estimating the sphericities based on the depths of the local minima in the scattering angular distributions, we found the ambient aerosols to be external mixtures of at least two types of particles, one with relatively high and the other with relatively low sphericity. Although most of the particles exhibiting high sphericity were removed as they passed through the thermodenuder, approximately one-third of the fraction exhibiting low sphericity remained. During the daytime, the proportion of the low-sphericity particles decreased, whereas the average sphericity of the high-sphericity particles increased, which can be attributed to photochemical formation and/or aging processes. On days with extremely high relative humidity, the diurnal variation in the average sphericity displayed another peak during the early morning, which may have been due to the secondary formation of nitrate.

Sphericity

Nephelometer

Particle (ecology)

10.4209/aaqr.2020.01.0023

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Citations (2)