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Xu, X.*; 大平 拓実*; Xu, S.*; 平田 研二*; 大森 俊洋*; 植木 洸輔*; 上田 恭介*; 成島 尚之*; 長迫 実*; 貝沼 亮介*; et al.
Advanced Materials & Processes, 180(7), p.35 - 37, 2022/10
Metallic biomaterials are widely used to replace or support failing hard tissues due to excellent mechanical properties and high wear resistance, with demand increasing as the global population continues to age. It is widely accepted that successful metallic biomaterials should have good biocompatibility, high corrosion resistance, and strong wear resistance. In addition, a low Young's modulus similar to human bone is now recognized as another important factor, in order to avoid bone atrophy due to the stress shielding effect. While the Young's modulus of stainless steels and conventional fcc CoCr alloys is as high as 190-240 GPa, for 
-type Ti-base alloys it is generally in the range of 50-80 GPa. Young's modulus values are as low as 35 GPa for Ti-Nb-Ta-Zr, close to that of human bone at approximately 10-30 GPa. However, Ti-base alloys come with the compromise of low wear resistance. In fact, alloys that feature a low Young's modulus along with high wear resistance have been difficult to realize. This article explores the recently developed bcc CoCr-base alloy Co-Cr-Al-Si as a potential solution to these issues, i.e., the difficulty in combining a low Young's modulus with high wear resistance, and the challenge of realizing large superelastic strains.
大平 拓実*; Xu, S.*; 平田 研二*; Xu, X.*; 大森 俊洋*; 植木 洸輔*; 上田 恭介*; 成島 尚之*; 長迫 実*; Harjo, S.; et al.
Advanced Materials, 34(27), p.2202305_1 - 2202305_11, 2022/07
被引用回数：12 パーセンタイル：87.73(Chemistry, Multidisciplinary)The demand for biomaterials has been increasing along with the increase in the population of elderly people worldwide. The mechanical properties and high wear resistance of metallic biomaterials makes them well-suited for use as substitutes or as support for damaged hard tissues. However, unless these biomaterials also have a low Young's modulus similar to that of human bones, bone atrophy inevitably occurs. Because a low Young's modulus is typically associated with poor wear resistance, it is difficult to realize a low Young's modulus and high wear resistance simultaneously. Also, the superelastic property of shape memory alloys makes them suitable for biomedical applications, like vascular stents and guide wires. However, due to the low recoverable strain of conventional biocompatible shape memory alloys, the demand for a new alloy system is high. The novel body-center-cubic cobalt-chromium-based alloys in this paper provide a solution to both of these problems. We believe our novel alloys are promising candidates for biomedical applications.
北里 宏平*; Milliken, R. E.*; 岩田 隆浩*; 安部 正真*; 大竹 真紀子*; 松浦 周二*; 高木 靖彦*; 中村 智樹*; 廣井 孝弘*; 松岡 萌*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
被引用回数：43 パーセンタイル：96.93(Astronomy & Astrophysics)2019年4月「はやぶさ2」ミッションは、地球に近い炭素質の小惑星(162173)リュウグウの人工衝撃実験を成功させた。これは露出した地下物質を調査し、放射加熱の潜在的な影響をテストする機会を提供した。はやぶさ2の近赤外線分光器(NIRS3)によるリュウグウの地下物質の観測結果を報告する。発掘された材料の反射スペクトルは、表面で観測されたものと比較して、わずかに強くピークがシフトした水酸基(OH)の吸収を示す。これは、宇宙風化や放射加熱が最上部の表面で微妙なスペクトル変化を引き起こしたことを示している。ただし、このOH吸収の強度と形状は、表面と同様に、地下物質が300
Cを超える加熱を経験したことを示している。一方、熱物理モデリングでは、軌道長半径が0.344AUに減少しても、推定される掘削深度1mでは放射加熱によって温度が200Cを超えて上昇しないことが示されている。これは、リュウグウ母天体が放射加熱と衝撃加熱のいずれか、もしくは両方により熱変化が発生したという仮説を裏付けている。
北里 宏平*; Milliken, R. E.*; 岩田 隆浩*; 安部 正真*; 大竹 真紀子*; 松浦 周二*; 荒井 武彦*; 仲内 悠祐*; 中村 智樹*; 松岡 萌*; et al.
Science, 364(6437), p.272 - 275, 2019/04
被引用回数：259 パーセンタイル：99.73(Multidisciplinary Sciences)小惑星探査機はやぶさ2のターゲット天体であるリュウグウは、始原的な炭素質物質で構成されていると考えられている。はやぶさ2に搭載された近赤外分光計(NIRS3)によって、天体の表面組成を得た。天体全体の観測で、弱く細い吸収が2.72ミクロンに確認され、OHを含む鉱物の存在を示している。弱いOH吸収と低いアルベドは熱やショックによって変質を受けた炭素質コンドライトに似ている。OHバンドの位置はほとんど一定であり、衝撃片の集合によって形成されたリュウグウは組成的に均質であることを示している。
岩田 隆浩*; 北里 宏平*; 安部 正真*; 大竹 真紀子*; 荒井 武彦*; 荒井 朋子*; 平田 成*; 廣井 孝弘*; 本田 親寿*; 今栄 直也*; et al.
Space Science Reviews, 208(1-4), p.317 - 337, 2017/07
被引用回数：54 パーセンタイル：71.62(Astronomy & Astrophysics)C型小惑星リュウグウを目指す小惑星探査機ハヤブサ2に搭載された近赤外分光計NIRS3は1.8から3.2ミクロンまでの感度を持つ。NIRS3は小惑星の反射スペクトルを計測することで、3ミクロンバンドに現れる水に起因する吸収を検出することを目的としている。InAsフォトダイオードリニアイメージセンサと188Kでの動作を可能とする受動冷却システムによって、本分光計は十分な感度とダークノイズを達成できる。NIRS3フライトモデルは打ち上げ前に地上で性能評価実験が行われ、小惑星表面の水質変成度を決定できるだけのSN比があることが確認された。小惑星表面の計測では、小惑星の熱変性度や、炭素質コンドライトとの対応関係を明らかにできるだろう。
ions中嶋 薫*; 永野 賢悟*; 鈴木 基史*; 鳴海 一雅; 齋藤 勇一; 平田 浩一*; 木村 健二*
Applied Physics Letters, 104(11), p.114103_1 - 114103_4, 2014/03
被引用回数：6 パーセンタイル：26.85(Physics, Applied)In the secondary ion mass spectrometry (SIMS), use of cluster ions has an advantage of having a high sensitivity of intact large molecular ions over monatomic ions. This paper presents further yield enhancement of the intact biomolecular ions with measuring the secondary ions emitted from a self-supporting thin film in the forward direction, which is the same direction as primary beams. Phenylalanine amino-acid films deposited on self-supporting thin Si
N
films were bombarded with 5-MeV C ions. Secondary ions emitted in the forward and backward directions were measured under the bombardments of the SiN and phenylalanine sides, respectively. The yield of intact phenylalanine molecular ions emitted in the forward direction is about one order of magnitude larger than the backward direction, while fragment ions of phenylalanine molecules are suppressed. This suggests a large potential of transmission cluster-ion SIMS for the analysis of biological materials.
Mn
Si/Ge(111) heteroepitaxial interfaces野口 雄也*; 平田 智昭*; 川久保 雄基*; 鳴海 一雅; 境 誠司; 前田 佳均
Physica Status Solidi (C), 10(12), p.1732 - 1734, 2013/12
被引用回数：0 パーセンタイル：0.01(Nanoscience & Nanotechnology)We have investigated thermal disordering and instability of Fe
MnSi (FMS) (111)/Ge(111) heterointerfaces by Rutherford-backscattering spectrometry (RBS), and found pronounced degradation of axial orientation which appears as increase of the minimum yield of RBS when the FMS samples are annealed above 300C. Analysis of interdiffusion at the heterointerface reveals that the disordering mainly comes from interdiffusion between Fe and Ge atoms. This situation is the same as that observed in off-stoichiometric FeSi, 
, FeSi, but far from that in stoichiometric FeSi.
(Mn
Fe)Si(111) epitaxially grown on Ge(111)川久保 雄基*; 野口 雄也*; 平田 智昭*; 鳴海 一雅; 境 誠司; 山田 晋也*; 浜屋 宏平*; 宮尾 正信*; 前田 佳均
Physica Status Solidi (C), 10(12), p.1828 - 1831, 2013/12
被引用回数：0 パーセンタイル：0.01(Nanoscience & Nanotechnology)We have investigated crystal quality of Co(MnFe)Si (CMFS) epitaxially grown on Ge(111) by using Rutherford-backscattering spectrometry and an axial-ion-channeling technique. It was found that the CMFS/Ge and CoFeSi (CMFS with x = 1)/Ge have larger static atomic displacement than Fe-based ternary Heusler alloy FeMnSi and FeCoSi/Ge(111). Quaternary alloys may be affected by increase of mixing entropy. Significant disordering at the interface of CMFS with x = 0.75 was found, and discussed on the basis of thermodynamics.
平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 鳴海 一雅
Nuclear Instruments and Methods in Physics Research B, 314, p.39 - 42, 2013/11
被引用回数：4 パーセンタイル：33.02(Instruments & Instrumentation)Secondary ion mass spectrometry (SIMS) is one of the most powerful tools for surface analysis. Use of a time-of-flight (TOF) mass spectrometry for SIMS is advantageous in efficiently detecting secondary ions at a wider range of mass to charge ratio. We have studied on TOF-SIMS utilizing cluster ions as primary ions. Their Energy dependence to the yield of secondary ions from organic thin films was obtained in the energy range up to MeV order. As a result, it was revealed that the secondary-ion yields for organic material increased with increasing incident cluster energy in the range. This shows that cluster impacts with the energy range of up to MeV order are useful in TOF-SIMS to be applied to the high sensitive analysis of surface for organic materials.
ions through micro- and nano-capillaries土田 秀次*; 間嶋 拓也*; 冨田 成夫*; 笹 公和*; 鳴海 一雅; 齋藤 勇一; 千葉 敦也; 山田 圭介; 平田 浩一*; 柴田 裕実*; et al.
Nuclear Instruments and Methods in Physics Research B, 315, p.336 - 340, 2013/11
被引用回数：3 パーセンタイル：26.71(Instruments & Instrumentation)Applying the beam-focusing method with capillaries to C projectiles in the velocity range between 0.14 and 0.2 a.u., transmission properties of C ions through two different types of capillaries are studied: (1) a borosilicate-glass single microcapillary with an outlet diameter of 5.5 
m, and (2) an AlO multicapillary foil with approximatey 70-nm pores in diameter and a high aspect ratio of approximately 750. Transmitted-particle compositions are measured with the electrostatic-deflection method combined with a two-dimensional position-sensitive detector. In the experiments with the single microcapillary, the main transmitted component is found to be primary C ions, which are focused in the area equal to the capillary outlet diameter. The other components are charge-exchanged C ions and charged or neutral fragments (fullerene-like C
and small C
particles), and their fractions decrease with decreasing projectile velocity. Similar results are obtained in the experiments with the multicapillary foil. It is concluded from the relative transimission fractions of more than 80% that the C transmission fraction is considerably high for both types of the capillaries in the present velocity range.
平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 鳴海 一雅; 神谷 富裕
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 165, 2013/01
Secondary ion (SI) mass spectrometry, based on the phenomenon that primary ion impacts on a target produce SIs originating from the target, is one of the most powerful tools for surface analysis. One of the difficulties in SI mass measurements of insulating targets is to stabilize the surface potential during the measurements, because ion impacts on insulating targets usually lead to an increase in the potential caused by the difference between the injected and emitted charges. We compared time-sequential variations of negative-SI TOF mass spectra of a thin PMMA film target for monoatomic (C
) and cluster ions (C
) impact with the same incident energy per atom (0.5 MeV/atom) to study difference in charging effects on N-SI mass spectra of insulating targets. For C impacts, the peak shift to longer flight time and SI intensity reduction are observed. In contrast to the C impacts, the N-SI TOF mass spectra for C do not show the peak shift and SI intensity reduction, which shows that the surface potential is stable during the C bombardment. The results demonstrate that N-SI TOF mass measurement of the insulating thin film target is available using cluster ions as a primary ion without charge compensation.
ion impacts平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 高橋 康之*; 鳴海 一雅; 神谷 富裕
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 156, 2012/01
Secondary ion (SI) yields from a Poly(tetrafluoroethylene) (PTFE) target for C ion impacts were measured with an energy range from 30 keV to 270 keV by time-of-flight (TOF) SI mass analysis combined with SI electric current measurements. As a result, the use of impacts of C ion with the increased incident energies (60 keV C, 120 keV C and 270 keV C
) provided higher yields of the characteristic positive SIs for PTFE than those of lower energy C ions (30-keV C) and advantageous for highly sensitive chemical analysis of PTFE.
impacts平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 鳴海 一雅
Applied Physics Express, 4(11), p.116202_1 - 116202_3, 2011/11
被引用回数：8 パーセンタイル：34.67(Physics, Applied)We report on the surface-sensitive chemical analysis of organic insulating thin films using negative secondary ions (N-SIs) induced by C impacts in the medium energy range from several tens to several hundreds keV. Incident C energy dependence of emission yields of characteristic N-SIs for poly(methyl methacrylate) and charging effects on the N-SI mass spectra were investigated using time-of-flight SI mass spectrometry. Our results show that medium energy C impacts stably provides considerably high characteristic N-SI yields without charge-compensation, and demonstrate that time-of-flight SI mass spectrometry with medium energy C impacts is advantageous for highly-sensitive chemical analysis of organic insulators.
平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 高橋 康之*; 鳴海 一雅
Review of Scientific Instruments, 82(3), p.033101_1 - 033101_5, 2011/03
被引用回数：10 パーセンタイル：44.79(Instruments & Instrumentation)We report suitable secondary ion (SI) counting for surface-sensitive chemical analysis of organic compounds using time-of-flight (TOF) SI mass spectroscopy, based on considerably higher emission yields of SIs induced by cluster ion impact ionization. A SI counting system for a TOF SI mass spectrometer was developed using a fast digital storage oscilloscope, which allows us to perform various types of analysis as all the signal pulses constituting TOF SI mass spectra can be recorded digitally in the system. Effects of the SI counting strategy on SI mass spectra were investigated for C and C cluster ion impacts on an organically contaminated silicon wafer and on polytetrafluoroethylene targets by comparing TOF SI mass spectra obtained from the same recorded signals with different SI counting procedures. Our results show that the use of a counting system, which can cope with high SI yields is necessary for quantitative analysis of SI mass spectra obtained under high SI yield per impact conditions, including the case of cluster ion impacts on organic compounds.
平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 高橋 康之; 鳴海 一雅
Nuclear Instruments and Methods in Physics Research B, 268(19), p.2930 - 2932, 2010/10
被引用回数：3 パーセンタイル：28.83(Instruments & Instrumentation)Emission yields of secondary ions necessary for the identification of poly-tyrosine were compared for incident ion impacts of energetic cluster ions (0.8 MeV C
, 2.4 MeV C, and 4.0 MeV C) and swift heavy monoatomic molybdenum ions (4.0 MeV Mo and 14 MeV Mo
) with similar mass to that of the cluster by time-of-flight secondary ion mass analysis combined with secondary ion electric current measurements. The comparison revealed that (1) secondary ion emission yields per C impact increase with increasing incident energy within the energy range examined, (2) the 4.0 MeV C impact provides higher emission yields than the impact of the monoatomic Mo ion with the same incident energy (4.0 MeV Mo), and (3) the 2.4 MeV C impact exhibits comparable emission yields to that for the Mo ion impact with higher incident energy (14 MeV Mo). Energetic cluster ion impacts effectively produce the characteristic secondary ions for poly-tyrosine, which is advantageous for highly sensitive amino acid detection in proteins using time-of-flight secondary ion mass analysis.
ion impact平田 浩一*; 齋藤 勇一; 千葉 敦也; 阿達 正浩*; 山田 圭介; 鳴海 一雅
Nuclear Instruments and Methods in Physics Research B, 266(10), p.2450 - 2452, 2008/05
被引用回数：13 パーセンタイル：64.63(Instruments & Instrumentation)Time-of-flight (TOF) secondary ion mass spectroscopy was performed using primary C ions with an energy range from several tens of keV to several hundreds of keV. Application of the spectroscopy to the analysis of a poly(amino acid) film revealed that characteristic peaks, necessary for identification of the amino acid in proteins, show higher intensities for medium energy C (120 keV C
and 540 keV C
) impacts than those for low energy C (30 keV C) impacts. This finding demonstrates that medium energy C ion impacts are useful for highly sensitive characterization of amino acids.
平田 浩一*; 齋藤 勇一; 千葉 敦也; 鳴海 一雅
Applied Physics Express, 1(4), p.047002_1 - 047002_3, 2008/04
被引用回数：4 パーセンタイル：18.78(Physics, Applied)Emission yields of carbon and hydrogenated carbon cluster secondary ions CpHq
(p
, q
) originating from organic contaminants on a silicon wafer are compared between monoatomic (0.5 MeV/atom-C1) and cluster ion (0.5 MeV/atom-C8) impacts using time-of-flight (TOF) secondary ion mass spectrometry. CpHq for the cluster ion impact exhibits the highest emission yield per incident atom among CpHq with the same p number. The highest relative CpHq emission yield for the cluster ion impact reaches 
and 
times higher in comparison with those of CpHq
and CpHq with the same p number for the impact of the monoatomic ion with the same velocity, respectively. Combination of negative secondary ion TOF measurements with cluster impact ionization is a promising tool for highly sensitive detection of organic-contaminants on silicon wafers.
林 巧; 小西 哲之; 大平 茂; 中村 博文; 井上 雅彦*; 渡辺 哲郎*; 平田 一弘*; 成瀬 雄二; 奥野 健二; Barnes, J. W.*; et al.
JAERI-M 93-094, 54 Pages, 1993/03
日米協力AnnexIVに基づいて米国ロスアラモス国立研究所のトリチウムシステム試験施設(TSTA)で行われている原研製の燃料精製システムの試験において、オイルフリー粗引き真空ポンプの1種であるスクロールポンプの軽原素ガスの排気特性を閉システムで測定した。圧縮比、到達真空などの性能は吐出側圧力の影響を受け、またガス種によって著しく異なることが見出された。特にH,Dでは性能は著しく劣化し、後段にメタルベローズポンプを設置することによって初めて窒素と同程度の排気が可能となる。水素同位体について排気特性は質量の増加と共に改善し、純トリチウムガスについてヘリウムとほぼ同等の結果が得られた。
林 巧; 小西 哲之; 中村 博文; 井上 雅彦*; 平田 一弘*; 奥野 健二; 成瀬 雄二; Barnes, J. W.*; W.Harbin*; Anderson, J. L.*; et al.
JAERI-M 93-084, 32 Pages, 1993/03
原研は日米核融合研究協力協定AnnexIVに基づき、米国ロスアラモス国立研究所TSTAにおいて核融合炉燃料ループの実証試験を行っている。本試験は、J-FCU(JAERI-燃料精製捕集装置)と全4塔を使用したISS(水素同位体分離装置)を連続した初めての試験であり、25日間連続TSTAループ運転試験の重要な部分として92年4-5月に行われた。試験中、J-FCUは常に安定かつ安全に運転され、ISSとの連結においても大きな問題はなかった。約5Nl/rain程度の、多岐にわたる不純物を含む模擬プラズマ排ガスを連続処理し、ISSへ純水素同位体を排出するとともに、トリチウムを含まないガスをTWT(トリチウム排ガス処理設備)へ排気した。本報告書は、上記J-FCUの性能試験に関する詳細結果をまとめたものである。
林 巧; 中村 博文; 小西 哲之; 井上 雅彦*; 平田 一弘*; 奥野 健二; 成瀬 雄二; Anderson, J. L.*; Sherman, R. H.*; Willms, R. S.*; et al.
JAERI-M 93-083, 54 Pages, 1993/03
原研は日米核融合研究協力協定AnnexIVに基づき、米国ロスアラモス国立研究所TSTAにおいて核融合燃料ループの実証試験を行っている。本試験は、TSTAループ全体の長期間安全定常運転の実証を最大の目的として、92年4-5月に行われたもので、AnnexIV最大のマイルストーンであった。試験は25日間におよぶ昼夜連続運転であったがISS(深冷蒸留水素同位体分離装置)、FCU(燃料精製・捕集装置)J-FCU(JAERI-燃料精製捕集装置)等すべてのサブシステムが安定に制御された。また、マグネシウムベッドを用いたFCU、及びJ-FCUは、はじめての全TSTAループとの連続運転であったが、不純物を含む模擬プラズマ排ガスを安全かつ安定に連続処理できることを実証した。本報告書は、上記試験における詳細試験計画と結果の概要をまとめたものである。
