R. Kawakami,N. Ohtsu,
Selective oxide layer formation on NiAl alloys by anodization with electrolyte variation,
The 11th International Conference on Technological Advances of Thin Films and Surface Coatings, ThinFilm 2026 (7/13-17, Singapore)
M. Tachibana, Y. Kitadate, M. Hirano,N. Ohtsu,
Analyses of metal surface reaction induced by laser-induced plasma toward improved nitride layer formation,
The 11th International Conference on Technological Advances of Thin Films and Surface Coatings, ThinFilm 2026 (7/13-17, Singapore)
(Invited) M. Hirano, K. Kitazawa, K. Kojima, N. kuraoka, N. Ohtsu,
Improving durability of stainless steel nanopillar surface structure to prevent antibacterial activity deterioration induced by abrasion
The 11th International Conference on Technological Advances of Thin Films and Surface Coatings, ThinFilm 2026 (7/13-17, Singapore)
A. Kitayama, R. Takada, Y. Tamashita, M. Hirano,N. Ohtsu,
Cell activity on pulsed-anodized NiTi alloy surfaces with enhanced hydrophilicity,
The 11th International Conference on Technological Advances of Thin Films and Surface Coatings, ThinFilm 2026 (7/13-17, Singapore)
(Invited)N. Ohtsu, A. Kitayama, R. Takada, Y. Tamashita, M. Hirano,
Hydrophilization of nickel-titanium alloy surfaces through pulse anodization for biomedical application,
The 11th International Conference on Technological Advances of Thin Films and Surface Coatings, ThinFilm 2026 (7/13-17, Singapore)
M. Hirano,K. Kitazawa, K. Kojima, N. Ohtsu,
Fabrication of nanotextured surfaces on AISI 316 stainless steel surface via radio-frequency magnetron argon plasma,
The 18th International Symposium on Sputtering & Plasma Processes, ISSP2026 (6/30-7/3, Kyoto, Japan)
M. Tachibana, E. Hashiba, Y. Kitadate, M. Hirano,N. Ohtsu,
Temporal and Spatial evaluation of laser induced plasma (LIP) aiming to improve the metal nitriding process in air,
The 18th International Symposium on Sputtering & Plasma Processes, ISSP2026 (6/30-7/3, Kyoto, Japan)
N. Ohtsu, M. Tachibana, E. Hashiba, Y. Kitadate, M. Hirano,T. Kiba, Laser
induced plasma processing to fabricate a nitride layer on a metal surface
utilizing a nitrogen present in air, The 18th International Symposium on
Sputtering & Plasma Processes, ISSP2026 (6/30-7/3, Kyoto, Japan)
N. Ohtsu, E. Hashiba, M. Tachibana, Y. Kitadate, R. Kawakami, M. Hirano,
A laser induced plasma processing for forming a tribological nitride coating on a metal surface,
20th International Conference on Thin Films, ICTF-20 (6/8-12, Biaritz, France)
N. Ohtsu, M. Tachibana, E. Hashiba, Y. Kitadate, M. Hirano,
Laser-induced plasma processing enabling open-air nitriding of metal surfaces,
Advances in Optics and Photonics, AdvOptix 2026 (5/25-27,Matsue, Japan)
M. Hirano, N. Ohtsu, Argon plasma etching process enhancing antibacterial
activity of stainless steel surface via nanopillar fabrication, 7th Asia
COnference on Material and Manufacturing Technology, ACMMT 2025 (11/4-7,
Pattaya, Thailand)
N. Ohtsu, R. Kawakami, M. Hirano, Pulsed anodization technology for improving
the surface biocompatibility of a superelastic NiTi alloy, 7th Asia COnference
on Material and Manufacturing Technology, ACMMT 2025 (11/4-7, Pattaya,
Thailand)
K. Kitazawa, N. Ohtsu, M. Hirano, Investigation of stainless steel nanopillar
surface structure to prevent antibacterial activity deterioration induced
by abrasion, Asian-European International Conference on Plasma Surface
Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
Y. Kitadate,A. Yoshino, K. Yonemoto, E. Hashiba, M. Hirano, N. Ohtsu, Wavelength
dependence in laser induced plasma used for fabricating a nitride titanium
surface in air, Asian-European International Conference on Plasma Surface
Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
R. Takada, A. Kitayama, M. Hirano, N. Ohts, Effect of the pulsed anodizing
duration on the layer characteristics of NiTi alloy, Asian-European International
Conference on Plasma Surface Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
N. Ohtsu, Y. Kitadate, M. Tachibana, M. Hirano, A metal surface nitriding
processable in air utilizing a laser induced plasma, Asian-European International
Conference on Plasma Surface Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
M. Hirano, N. Ohtsu, Antibacterial nanopillar formation on stainless steel
surface utilizing argon plasma etching process, Asian-European International
Conference on Plasma Surface Engineering, AEPSE 2025 (11/2-6, Phuket, Thailand)
(Invited) N. Ohtsu, R. Kawakami, M. Hirano, Pulsed anodization process to form a
biocompatible layer on superelastic NiTi alloy surface, International Conference
on Processing & Manufacturing of Advanced Materials, THERMEC'2025 (6/30-7/4,
Tours, France)
(Invited) M. Hirano, K. Miura, N. Ohtsu, R. Kawakami, M. Hirano, Argon plasma etching
process to fabricate the antibacterial nanopillars on stainless steel surface,
International Conference on Processing & Manufacturing of Advanced
Materials, THERMEC'2025 (6/30-7/4, Tours, France)
(Invited) N. Ohtsu, Wear Resistance Improvement of Stainless Steels by An Open Atmosphere
Laser Nitriding, 13th Asia Conference on Mechanical and Materials Engineering,
ACMME' 2025 (6/18-21, Tokyo, Japan)
(Invited) N. Ohtsu, Pulsed anodization to form a biocompatible oxide layer on a
superelastic NiTi alloy, 4th International Symposium on Anodizing Science
and Technology, AST 2025 (6/1-6/4, Narita, Japan)
A. Kitayama, R. Takada, R. Kawakami, M. Hirano, N Ohtsu, Pulsed anodization
to form a biocompatible oxide layer on a superelastic NiTi alloy, 4th International
Symposium on Anodizing Science and Technology, AST 2025 (6/1-6/4, Narita,
Japan)
N. Ohtsu, K. Yonemoto, A. Yoshino, Y. Kitadate, M. Nakai, M. Hirano, Wear
resistance improvement of steinles sttel by a facile laser surface processing,
The14th TSME International Conference on Mechanical Engineering, TSME-ICOME
2024 (12/10-13,Pattaya, Thailand)
(Invited)N. Ohtsu, An open atmosphere laser nitriding on metal surfaces utilizing
a laser induced plasma, 6th Asia Conference on Material and Manufacturing
Technology, ACMMT 2024 (11/25-28, Online)
M. Hirano, K. Maruyama, N. Ohtsu, Enhancing hardness of commercial pure
Ti via radio-frequency magnetron He plasma, The 12th Vacuum and Surface
Science Confernce of Asia and Australia, VASSCAA-12 (10/13-17, Taipei,
Taiwan)
N. Ohtsu, A. Yoshino, K. Yonemoto, An open atmosphere nitriding phenomenon
on metal surfaces triggered by laser induced plasma, 19th Conference on
Plasma Surface Engineering, PSE 2024 (9/2-5, Erfurt, Germany)
K. Yonemoto, A. Yoshino, Y. Kitadate, N. Ohtsu, Characteristic variation
of the focused pulsed laser-irradiated titanium surface in N2-O2 atmosphere
with different mixture ratio, 19th Conference on Plasma Surface Engineering,
PSE 2024 (9/2-5, Erfurt, Germany)
A. Yoshino, K. Yonemoto, Y. Kitadate, T. Kiba, N. Ohtsu, Optimization of
laser-induced plasma for facilitating the open atmosphere laser nitriding
on titanium surface, 19th Conference on Plasma Surface Engineering, PSE
2024 (9/2-5, Erfurt, Germany)
N. Ohtsu, R. Takada R. Kawakami, Dominant characteristic of an anodized
NiTi alloy surface that suppress a Ni ion release in biological environment,
European Conference on Application of Surface and Interface Analysis, ECASIA
2024 (6/9-14,Gothenburg,Sweden)
N. Ohtsu, A. Tsuruta, R. Kawakami, M. Hirano, Fabrication of high durability
photocatalytic N-doped TiO2 layer on Ti substrate through anodization in
hot non-aqueous nitrate electrolyteals, The International Conference on
Applied Physics and Materials Applications, ICAPMA2023 (12/6-9, Pattaya,
Thailand)
(Invited) N. Ohtsu, H. Taniho, K. Tate, Z. Wang, M. Ohta, Pulsed anodization to
improve the biocompatibility of superelastic NiTi alloy, The 11th Pacific
Rim International Conference on Advanced Materials and Processing, PRICM
11 (11/19-23, Jeju, Korea)
Y. Matsui, R. Kawakami, Y. Sakurai, N. Ohtsu, Endothelial cell behavior
on pulsed-anodized NiTi alloys using different electrolytes , The 11th
Pacific Rim International Conference on Advanced Materials and Processing,
PRICM 11 (11/19-23, Jeju, Korea)
R. Kawakami, Y. Matsui, R. Takada, N. Ohtsu, Variation of Ni ion release
behavior of a pulsed-anodized NiTi alloy surface by a voltage setting ,
The 11th Pacific Rim International Conference on Advanced Materials and
Processing, PRICM 11 (11/19-23, Jeju, Korea)
N. Ohtsu, An open atmosphere nitriding phenomenon on metal surfaces triggered
by laser induced plasma, Euromat'2023 (9/3-7, Frankfurt, Germany)
R. Kawakami, K.Tate, Y. Matsui, A. Tsuruta, N. Ohtsu, Variation of Ni-ion
release behaviour of the pulsed anodized NiTi alloy by the adjustment of
pulse waveform, International Conference on Processing & Manufacturing
of Advanced Materials, Thermec'2023 (7/2-7, Vienna, Austria)
(Invited) N. Ohtsu, R. Endo, S. Takeda An open atmosphere nitriding phenomenon on
metal surfaces triggered by laser induced plasma , International Conference
on Processing & Manufacturing of Advanced Materials, Thermec'2023 (7/2-7,
Vienna, Austria)
Y. Sakuraba, N. Ohtsu, R. Kawakami, Hardness distribution generation in
a welded AISI H13 steel and its removal by laser heat treatment, International
Conference on Processing & Manufacturing of Advanced Materials, Thermec'2023
(7/2-7, Vienna, Austria)
(Invited)N. Ohtsu, An open atmosphere laser nitridng process on titanium, 2nd International
Materials Engineering and Advanced Manufacturing Technologies Congress,
IMEAMTC'23, (1/12〜13, Online)
N. Ohtsu, Fractional Analysis Process of Surface-Adsorbed Proteins Using
Sds-Page, Pacific Rim Symposium on Surface, Coatings & Interface, PacSurf
2022 (12/11〜15, Hawaii)
K. Tate、Y. Matsui, R. Kawakami, N. Ohtsu, Cell responses on pulsed-anodized
nitinol alloy with different surface property, 6th International Conference
on Nanomaterials and Biomaterials,ICNB 2022 (11/12〜14, Bangkok)
S. Takeda, M. Hiranoi, N. Ohtsu, Fabrication of antibacterial nanopillars
on AISI 316 surface via argon plasma etchingprocess, 4th Asia Conference
on Material and Manufacturing Technology, ACMMT 2022 (11/12〜14, Bangkok)
R. Endo, S. Takeda, N. Ohtsu, A nitride layer formation on titanium surface
through laser irradiation in an open atmospheric condition, 4th Asia Conference
on Material and Manufacturing Technology, ACMMT 2022 (11/12〜14, Bangkok)
M. Hirano, S. Taleda, N. Ohtsu, Effect of crystal phase and composition
of stainless steels on antibacterial nanopillar surface fabricated by argon
plasma etching, 22th International Vacuum Congress, IVC-22 (9/11〜16, Sapporo)
H. Taniho, K. Tate、R. Kawakami, N. Ohtsu, Characteristic variation of pulsed
anodized NiTi surface caused by the voltage-OFF period, Materials Research
Meetin 2021, MRM2021(12/13〜16, Yokohama)
K.Tate, H. Taniho, R. Kawakami, N. Ohtsu, Cell responses on a pulsed anodized
NiTi surface with a different Ni releasing behavior, Materials Research
Meetin 2021, MRM2021(12/13〜16, Yokohama)
Y. Yotsuji, Y. Funane, N. Ohtsu, Investigation of photocatalytic antiviral
performance on an anodized titanium surface using a temperature-controlled
alcoholic nitrate electrolyte, Materials Research Meetin 2021, MRM2021(12/13〜16,
Yokohama)
(Invited) N. Ohtsu, H. Taniho, K. Tate, Z. Wang, M. Ohta Biological responses on
a surface modified nitinol alloy through the anodization technique, 18th
International Conference on Flow Dynamics, ICFD2021,(10/27-29, Virtual)
K. Yamasaki, H. Taniho, K. Tate, N, Ohtsu, Ni ion release from a pulsed
anodized NiTi alloy surface using various electrolytes, 14th Inbternarional
COnference on Surfaces, Coatings and Nanostructured Materials, NANOSMAT
2020 (9/8〜10, Virtual)
M.Hirano, S. Takeda, K. Miura, M. Yamane, N. Ohtsu, Fabrication of antibacterial
nanopillars on stainless steel surface , 14th Inbternarional COnference
on Surfaces, Coatings and Nanostructured Materials, NANOSMAT 2020 (9/8〜10,
Virtual)
H. Taniho, K. Yamasaki, N. Ohtsu, Enhancement of Ni release inhibition
effect on pulsed anodized NiTi alloy through the pulse width optimization,
14th Inbternarional COnference on Surfaces, Coatings and Nanostructured
Materials, NANOSMAT 2020 (9/8〜10,Virtual)
Y.Funane, S. Yotsuji, N. Ohtsu, Improvement of performances on anodic TiO2
layer using nitrate/non-aqueous electrolyte via temperatures optimization,
14th Inbternarional COnference on Surfaces, Coatings and Nanostructured
Materials, NANOSMAT 2020 (9/8〜10,Virtual)
M.Hirano, K. Miura, M. Yamane, N. Ohtsu, Fabrication of antibacterial nanopillars
on stainless steel surface, 11th World Biomaterials Congress, WBC 2020
(12/11〜15, Virtual)
N. Ohtsu, T. Kawakami, Y. Konaka, K. Kuroda, Establishment of fractional
determination process of adsorbed proteins on titanium surface using SDS-PAGE,
11th World Biomaterials Congress, WBC 2020 (12/11〜15, Virtual)
N. Ohtsu, M. Gotoh, Y. Kohari, Y. Shimotori, T.-Y. Chiou, Y. Nagata, H.
Arai, M. Murata, Production of antimicrobial agent from a peppermint herbal
water, International Conference on Functional Materials and Chemical Engineering,
ICFMCE 2019 (12/15〜17, Bangkok, Thailand)
N. Ohtsu, T. Kawakami, Y. Konaka, K. Kuroda,Fractional analytical procedure
for adsorbed proteins onto a material surface, International Conference
on Materials and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya,
Japan)
R. Kuroda, K. Kuroda, M. Okido, K. Yamaguchi, N. Ohtsu, Antibacterial Properties
of Ti Surface Using Metallic Ions Adsorption, International Conference
on Materials and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya,
Japan)
K. Yamasaki, K. Takiguchi, S. Komai, N. Ohtsu, Surface characteristics
and Ni ion release behavior of anodized NiTi alloy surface using the mixed
electrolyte comprising HNO3 and H3PO4 , International Conference on Materials
and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya, Japan)
K. Miura,M. Yamane, N. Ohtsu, Phase control of the plasma-nitrided SUS316
surface by N2 and H2 gas mixture ratio, International Conference on Materials
and Systems for Sustainability, ICMaSS 2019 (11/1〜3, Nagoya, Japan)
N. Ohtsu, M. Oku, K. Wagatsuma, XPS spectra of clean metallic silicide
surfaces obtained by in-situ fracture, European Conference on Application
of Surface and Interface Analysis, ECASIA 2019 (9/16〜20, Dresden, Germany)
T. Kawakami, H. Sawagucti, T. Syouji, N. Ohtsu, Effect of the surface chemical
state on competitive protein adsorption on titanium surface : A combinational
analysis using SDS-PAGE and XPS, European Conference on Application of
Surface and Interface Analysis, ECASIA 2019 (9/16〜20, Dresden, Germany)
S. Komai, M. Hirano, N. Ohtsu, Characterization of strontium-contained
apatite layer fabricated using calcium-phosphate slurry processing, European
Conference on Application of Surface and Interface Analysis, ECASIA 2019
(9/16〜20, Dresden, Germany)
K. Yamaguchi, Y. Funane, Y. Konaka, N. Ohtsu, Characteristics of anodic
oxide layer on titanium substrate using nitrate electrolyte in various
alcohols as solvent, European Conference on Application of Surface and
Interface Analysis, ECASIA 2019 (9/16〜20, Dresden, Germany)
M. Hirano, M. Yamane, N. Ohtsu, Hydrophilic properties of plasma-treated
titanium surface : Effect of gas composition and discharge modes, European
Conference on Application of Surface and Interface Analysis, ECASIA 2019
(9/16〜20, Dresden, Germany)
K. Takiguchi, M. Yamane, N. Ohtsu, Surface modification of pure iron through
a focused pulse Nd: YAG laser irradiation in nitrogen atmosphere, European
Conference on Application of Surface and Interface Analysis, ECASIA 2019
(9/16〜20, Dresden, Germany)
S. Komai, M. Hirano, N. Ohtsu, Preparation of strontium-doped apatite layer
on titanium substrate through calcium phosphate slurry processing and ion
release from the layer, International Symposium for Advanced Materials
Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
K. Takuguchi, K. Yamasaki, N. Ohtsu, Effect of anion species and concentration
in electrolyte on NiTi anodization, International Symposium for Advanced
Materials Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
K. Yamaguchi, Y. Funane, N. Ohtsu, Comparison of anodized layer on titanium
using nitrate electrolyte in various alcohol solvents for investigating
layer growth mechanism, International Symposium for Advanced Materials
Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
(Invited) N. Ohtsu , Simple chemical treatment process to give osteoconductivity
and antibacterial efficacy on titanium implant , International Symposium
for Advanced Materials Research, ISAMR 2019 (8/22〜25, Kaohsiung, Taiwan)
N. Ohtsu, Y. Hirano, K. Yamaguchi, K. Yamasaki, Surface characteristics,
Ni ion release, and antibacterial efficacy of anodized NiTi alloy using
HNO3 electrolyte of various concentrations, International Conference on
Applied Surface Science, ICASS 2019 (6/17〜20, Pisa, Italy)
K. Yamaguchi, Y. Konaka, N. Ohtsu, Fabrication of a photocatalytic antibacterial
layer on a Ti material through anodization with nitrate/glycerol electrolyte,
Anodizing Science Technology, AST 2019 (6/2〜5, Awaji, Japan)
N. Ohtsu, Y. Hirano, K. Takiguchi, K. Yamasaki, Oxide layer growth on nickel-titanium
alloy through anodization , Anodizing Science Technology, AST 2019 (6/2〜5,
Awaji, Japan)
N. Ohtsu, T.Kuji, M. Hirano, Roles of Anodic Oxide Layer on the Improvement
of Cellular Response of Titanium Implan, Pacific Rim Symposium on Surface,
Coatings & Interface, Pacsurf 2018 (12/2〜6, Waikoloa, Hawaii)
N. Ohtsu, Y. Hirano, H. Arai, Control of Ni ion release from NiTi shape
memory alloy using anodization in HNO3 electrolyte, 18th Asia Pacific Corrosion
Control COnference, APCCC-18 (11/5〜9, Pattaya, Thailand)
N. Ohtsu, Y. Hirano, Corrosion behavior of nickel-titanium alloy with TiO2
layer formed via anodization in HNO3 electrolytes, The 9th Vacuum and Surface
Science Conferene of Asia and Australia, VASSCAA-9 (8/13〜16, Sydney, Australia)
K. Sakamoto, F. Hayashi, N. Ohtsu, Formation of Ni-free oxide layer on
NiTi alloy by a combination of chemical and thermal treatments, THERMEC'2018
-International Conference on processing & manufacturing of advanced
materials (7/8〜13, Paris, France)
(Invited) N. Ohtsu, T. Kuji, M. Hirano, Effects of processing voltage on cellular
response of titanium anodized in phosphoric acid electrolyte, THERMEC'2018
-International Conference on processing & manufacturing of advanced
materials (7/8〜13, Paris, France)
N. Ohtsu, Y. Kakuchi, T. Ohtsuki, Y. Yokoiwa, Antibacterial efficacy of
hydroxyapatite coating including Zn formed by chemical solution deposition,
2nd International Conference on Applied Surface Science (6/12〜15, Dalian,
China)
N. Ohtsu, Y. Hirano, Comparison of nickel-titanium alloy surface anodized
in phosphoric- and sulfuric-acid electrolytes, 17th European Conference
on Applications of Surface and Interface Analysis (9/24〜29, Montpellier,
France)
(Invited) N. Ohtsu, Y. Kakuchi, Y. Yoshida, Antibacterial hydroxyapatite coating
on titanium via a simple chemical treatment process using calciunm phosphate
slurry, 18th International Union of Materials Research Society - Internationa
Conference in Asia (11/5〜9, Taipei, Taiwan)
Y. Hirano, N. Ohtsu, Effect of HNO3 concentration on the surface morphology
and layer thickness of the anodic oxide layer on NiTi alloy, 18th International
Union of Materials Research Society - Internationa Conference in Asia (11/5〜9,
Taipei, Taiwan)
M. Bai, N. Ohtsu, Effect of water addition to NH4NO3/ethylene glycol electrolyte
on the growth of anodic layer on titanium, 18th International Union of
Materials Research Society - Internationa Conference in Asia (11/5〜9, Taipei,
Taiwan)
N. Ohtsu, H. Arai, Calcium-phosphate slurry processing: a novel chemical
treatment technique to activate osteogenesis on titanium, 10nd World Biomaterials
Congress (5/17〜22, Montreal, Canada)
N. Ohtsu, T. Kozuka, M. Yamane, K. Ishikawa, Improvement of high temperature
stability of Pd-coated Nb using surface plasma nitriding, 15th International
Symposium on Metal-Hydrogen System (8/7〜12, Interlaken, Switzerland)
Y. Hirano, Y. Kakuchi, N. Ohtsu, A chemically stable TiO2 layer formation
on NiTi alloy by electrochemical process, Pure and Applied Chemistry International
Conference 2017 (2/2〜3, Bangkok, Thai)