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論文

Nacre-like MXene/polyacrylic acid layer-by-layer multilayers as hydrogen gas barriers

Auh, Y. H.*; Neal, N. N.*; Arole, K.*; Regis, N. A.*; Nguyen, T.*; 小川 修一*; 津田 泰孝; 吉越 章隆; Radovic, M.*; Green, M. J.*; et al.

ACS Applied Materials & Interfaces, 17(21), p.31392 - 31402, 2025/05

 被引用回数:16 パーセンタイル:89.85(Nanoscience & Nanotechnology)

MXenes are a promising class of 2D nanomaterials and are of particular interest for gas barrier application. However, MXene nanosheets naturally bear a negative charge, which prevents assembly with negatively charged polymers, such as polyacrylic acid (PAA), into gas barrier coatings. Here, we present MXene- and PAA-based layer-by-layer (MXene/PAA LbL) multilayers formed by leveraging hydrogen bonding interactions. When assembled in acidic conditions, MXene/PAA LbL films exhibit conformal, pin-hole free, nacre-like structures. The MXene/PAA LbL films yield high blocking capability and low permeability (0.14$$pm$$0.01 cc mm m$$^{-2}$$ day$$^{-1}$$ MPa$$^{-1}$$) for hydrogen gas. These nacre-like structures are also electronically conductive (up to 370$$pm$$30 S cm$$^{-1}$$). Specifically, the reversible deconstruction of these films under basic conditions is experimentally verified. This study shows that hydrogen bonding interactions can be leveraged to form MXene LbL multilayers as gas barriers, electronically conducive coatings, and deconstructable thin films via pH control.

論文

Extraction of $$^{99}$$Mo hot atoms made by a neutron capture method from $$alpha$$-MoO$$_{3}$$ to water

Quach, N. M.*; Ngo, M. C.*; Yang, Y.*; Nguyen, T. B.*; Nguyen, V. T.*; 藤田 善貴; Do, T. M. D.*; 中山 忠親*; 鈴木 達也*; 末松 久幸*

Journal of Radioanalytical and Nuclear Chemistry, 332(10), p.4057 - 4064, 2023/10

 被引用回数:5 パーセンタイル:56.11(Chemistry, Analytical)

テクネチウム-99m($$^{99m}$$Tc)は世界で最も広く使用されている医療用ラジオアイソトープであり、モリブデン-99($$^{99}$$Mo)から生成される。核不拡散の観点から中性子放射化法による$$^{99}$$Mo生成は核分裂由来の$$^{99}$$Moの代替法として注目を集めているが、$$^{99}$$Mo比放射能が極めて低いという欠点が存在する。本研究では、$$^{99}$$Mo抽出による比放射能向上を目的に、照射ターゲットとしてポーラス$$alpha$$-MoO$$_{3}$$ワイヤーを準備した。ポーラス$$alpha$$-MoO$$_{3}$$ワイヤーは、2段階の加熱手順によって金属Moワイヤーから調製する。中性子照射後のポーラス$$alpha$$-MoO$$_{3}$$ワイヤーおよび抽出に用いた水の放射能測定と同位体測定から$$^{99}$$Moのホットアトム効果を確認した。また、ポーラス$$alpha$$-MoO$$_{3}$$ワイヤーと市販の$$alpha$$-MoO$$_{3}$$粉末での$$^{99}$$Mo抽出率を比較した結果、同等の抽出率が得られた。

論文

Event structure and double helicity asymmetry in jet production from polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07

 被引用回数:36 パーセンタイル:75.17(Astronomy & Astrophysics)

重心エネルギー200GeVでの縦偏極陽子陽子衝突からのジェット生成のイベント構造と二重非対称($$A_{LL}$$)について報告する。光子と荷電粒子がPHENIX実験で測定され、イベント構造がPHYTIAイベント生成コードの結果と比較された。再構成されたジェットの生成率は2次までの摂動QCDの計算で十分再現される。測定された$$A_{LL}$$は、一番低い横運動量で-0.0014$$pm$$0.0037、一番高い横運動量で-0.0181$$pm$$0.0282であった。この$$A_{LL}$$の結果を幾つかの$$Delta G(x)$$の分布を仮定した理論予想と比較する。

論文

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉 康之*; Al-Bataineh, H.*; Alexander, J.*; 青木 和也*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 被引用回数:200 パーセンタイル:99.33(Physics, Nuclear)

200GeVと62.4GeVでの陽子陽子の中心衝突からの$$pi, K, p$$の横運動量分布及び収量をRHICのPHENIX実験によって測定した。それぞれエネルギーでの逆スロープパラメーター、平均横運動量及び単位rapidityあたりの収量を求め、異なるエネルギーでの他の測定結果と比較する。また$$m_T$$や$$x_T$$スケーリングのようなスケーリングについて示して陽子陽子衝突における粒子生成メカニズムについて議論する。さらに測定したスペクトルを二次の摂動QCDの計算と比較する。

論文

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉 康之*; Al-Bataineh, H.*; Alexander, J.*; 青木 和也*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 被引用回数:10 パーセンタイル:53.41(Physics, Nuclear)

重いフレーバーのメソンの崩壊からの電子の測定は、このメソンの収量が金金衝突では陽子陽子に比べて抑制されていることを示している。われわれはこの研究をさらに進めて二つの粒子の相関、つまり重いフレーバーメソンの崩壊からの電子と、もう一つの重いフレーバーメソンあるいはジェットの破片からの荷電ハドロン、の相関を調べた。この測定は重いクォークとクォークグルオン物質の相互作用についてのより詳しい情報を与えるものである。われわれは特に金金衝突では陽子陽子に比べて反対側のジェットの形と収量が変化していることを見いだした。

論文

Measurement of neutral mesons in $$p$$ + $$p$$ collisions at $$sqrt{s}$$ = 200 GeV and scaling properties of hadron production

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03

 被引用回数:190 パーセンタイル:98.22(Astronomy & Astrophysics)

RHIC-PHENIX実験で重心エネルギー200GeVの陽子陽子衝突からの$$K^0_s$$, $$omega$$, $$eta'$$と$$phi$$中間子生成の微分断面積を測定した。これらハドロンの横運動量分布のスペクトルの形はたった二つのパラメーター、$$n, T$$、のTsallis分布関数でよく記述できる。これらのパラメーターはそれぞれ高い横運動量と低い横運動量の領域のスペクトルを決めている。これらの分布をフィットして得られた積分された不変断面積はこれまで測定されたデータ及び統計モデルの予言と一致している。

論文

Emulsion grafting of glycidyl methacrylate onto polyethylene fiber

瀬古 典明; Nguyen, T. Y. N.*; 玉田 正男

Radiation Physics and Chemistry, 79(1), p.22 - 26, 2010/01

 被引用回数:49 パーセンタイル:93.25(Chemistry, Physical)

基材にはポリエチレン繊維を用い、ドデシル硫酸ナトリウム(SDS)を界面活性剤に用いたグリシジルメタクリレート(GMA)のエマルショングラフト重合を行った。エマルション溶液を構成するミセルは5%GMAと4%SDSの系で415nm、5%GMAと16%SDSの径では、ミセル径が1840nmであり、SDS濃度の増加とともに径は大きくなる傾向を示した。その際のグラフト率は各々120%と16%であり、ミセルの径がグラフト反応効率に大きく影響することがわかった。

論文

Use of positron-emitting tracer imaging system for measuring the effect of salinity on temporal and spatial distribution of $$^{11}$$C tracer and coupling between source and sink organs

諏訪 竜一*; 藤巻 秀; 鈴井 伸郎; 河地 有木; 石井 里美; 阪本 浩一*; Nguyen, N. T.*; 実岡 寛文*; Mohapatra, P. K.*; Moghaieb, R. E.*; et al.

Plant Science, 175(3), p.210 - 216, 2008/09

 被引用回数:26 パーセンタイル:53.82(Biochemistry & Molecular Biology)

Salinity stress affects photosynthate partitioning between sources and sinks of plants, but how it affects on these systems is less understood. Because sources and sinks are closely knitted, any adverse effect under sub-optimal condition on one part is often misinterpreted for the other. Knowledge on regulation of carbon partitioning is indispensable for stress resistance and good plant growth. In the present study, alteration of carbon partitioning in tomato plants (lycopersicon esculentum L. cv. Momotarou) under saline (NaCl) environment was studied by feeding radioactive $$^{11}$$C and stable $$^{13}$$C isotopes. Pulse chases were conducted for measuring spatial and temporal distributions of $$^{13}$$C. $$^{13}$$C was measured by standard conventional technique, but $$^{11}$$C distribution was monitored using by PETIS. Salt stress resulted in reduced carbon translocation towards roots. Majority of the photosynthate accumulated in the leaf. We have also observed that the reduction in translocation of carbon occurred well before salt stress symptoms of reduced photosynthesis and plant growth in salt exposed plants. The effect on sink activity also showed by decrease in stem diameter and reduced photosynthetic activity. In addition, PETIS analysis of $$^{11}$$C translocation indicates that carbon translocation to roots was inhibited under salt conditions without direct effect of leaf Na accumulation and osmotic stress These results suggest that NaCl has direct effects on plants inhibiting carbon partitioning within few hours of salt solution exposure without inhibition of source activity.

口頭

Study on secondary hydriding effects during simulated LOCA tests on the embrittlement and fracture behaviors of Cr-coated Zr-based alloy cladding

Nguyen, T. H.; Luu, V. N.; 谷口 良徳; 宇田川 豊; 勝山 仁哉; 垣内 一雄

no journal, , 

The proposed use of chromium (Cr)-coated zirconium (Zr)-based alloy cladding as an accident-tolerant fuel (ATF) highlights the importance of understanding its mechanical response under loss-of-coolant-accident (LOCA) conditions. In anticipation of the deployment of Cr-coated cladding, it is necessary to establish appropriate LOCA safety criteria and verify existing fuel performance codes. Under LOCA scenarios, fracture may occur either at the locations with oxidation or secondary hydriding. Nagase and Fuketa evaluated fracture maps at the rupture site as a function of the initial hydrogen content, however, no correlation was reported between fracture limits and post-LOCA hydrogen content. Alakiozidis at al. reported a hydrogen threshold of approximately 2700 ppm for out of burst failure in both coated and uncoated claddings; however, experimental data for coated claddings remains limited. This study aims to evaluate the effects of hydrogen on cladding embrittlement and fracture characteristics of Cr-coated cladding. To this aim, oxidation tests were conducted on Cr-coated claddings with controlled pre-hydrogen absorption to simulate low hydrogen concentrations, and integral LOCA tests were performed on both Cr-coated and uncoated claddings to evaluate secondary hydriding effects. For both tests, cladding tube samples were two sided steam oxidized to achieve equivalent cladding reacted (ECR) values ranging from 10 to 40%, corresponding to oxidation temperatures of 1200 and 1350$$^{circ}$$C for various exposure times in a vertical furnace, followed by water quenching at 700$$^{circ}$$C. Post-test examination includes the hydrogen measurement, microstructure observation by optical microscopy (OM) and scanning electro-microscopy (SEM), Vickers hardness test and nanoindentation. According to the results obtained, hydrogen promotes embrittlement of prior $$beta$$-Zr after exposure at 1200$$^{circ}$$C, while having no significant effect after exposure at 1350$$^{circ}$$C. The eutectic layer forms after exposure of Cr-coated cladding to 1350$$^{circ}$$C. This region consists of two distinct phases: a Cr-rich and a prior $$beta$$-Zr phase. Cr-rich phase exhibits higher nano-hardness than that of prior $$beta$$-Zr phase and hydrogen absorption enhances the hardness of both phases. The fracture threshold of Cr-coated cladding is determined by different controlling mechanisms at burst and out-of-burst positions. At the burst, fracture limits were found to be decreased with increasing hydrogen content (up to approximately 500 ppm), and the Cr-coated cladding fractured at longer oxidation time than uncoated cladding. At out-of-burst positions, no fracture observed up to 2700 ppm hydrogen, in agreement with Alakiozidis et al. and fracture limit was determined based on the remaining prior $$beta$$-Zr thickness at oxygen concentrations $$leqq$$ 0.9 wt% by Chung [3]. These findings indicate that the Cr-coated cladding exhibits hydrogen-related embrittlement behavior similar to conventional Zr alloys, with the additional advantage of reduced oxidation kinetics, which mitigates oxidation-driven embrittlement.

口頭

Isotope production using novel MoO$$_{3}$$ targets; Contribution by vietnamese institutes, staffs and students

末松 久幸*; Ngo, M. C.*; Quach, N. M.*; 藤田 善貴; Do, T. M. D.*; 中山 忠親*; 鈴木 達也*; Nguyen, V. T.*; 新原 晧一*

no journal, , 

放射性医薬品はさまざまな医療診断/治療に使用されており、その市場は15年間で10倍に成長している。その中でガンマ線診断に広く使用される$$^{99m}$$Tcの原料である$$^{99}$$Moは、現在高濃縮ウランを原子炉で照射することで核分裂生成物として生成されている。しかし、核不拡散の観点からウランの低濃縮化が世界的に進んでおり、$$^{98}$$Mo(n,$$gamma$$)$$^{99}$$Mo反応による$$^{99}$$Mo製造が注目されている。本研究では、中性子照射ターゲットとしてMoO$$_{3}$$の低温相である$$beta$$-MoO$$_{3}$$が、ホットアトム効果によりターゲットから水への$$^{99}$$Moの拡散を促進することを明らかにした。この現象を利用することで、$$^{99}$$Moおよび$$^{99m}$$Tcの安定供給に貢献できる。本成果では、ベトナム原子力研究所のダラット原子炉において$$alpha$$-MoO$$_{3}$$粉末ターゲットを用いた初の核反応中・水分散実験を実施し、ホットアトム効果を確認した後、ベトナムの学生と職員が新たに$$beta$$-MoO$$_{3}$$ウィスカーターゲットを用いることで水への拡散効率を飛躍的に向上させた。本研究における彼らの貢献についてプレゼンテーションで説明する。

口頭

Study on fracture behavior of Cr-coated Zr-based alloy claddings under high-temperature LOCA conditions

Luu, V. N.; 谷口 良徳; Nguyen, T. H.; 宇田川 豊; 田崎 雄大; 三原 武; 勝山 仁哉; 垣内 一雄

no journal, , 

To obtain the knowledge and data necessary for the regulatory assessment of Cr coated Zr-based alloy claddings, which is expected to be installed to Japanese plants in the near future, integrated LOCA tests were conducted using 190mm-long uncoated and Cr-coated Zr-based alloy claddings filled with zirconia pellets to simulate the thermal behavior of UO$$_{2}$$ pellets. The test rod was initially pressurized to 5 MPa and heated in 100% steam atmosphere at a heating rate of 5 K/s until burst. This was followed by isothermal oxidation at temperatures between 1200 and 1350$$^{circ}$$C and quenching at 700$$^{circ}$$C under an axial constraint of $$sim$$500N. The test temperature covered conditions both below and above the Zr/Cr eutectic temperature ($$sim$$1320$$^{circ}$$C) to establish fracture limits under LOCA conditions. Post-test observations showed that fractures into two segments occurred only at the burst locations due to circumferential cracking. Below the eutectic temperature, the fracture limit exceeded 28% BJ ECR (Equivalent Cladding Reacted calculated using the Baker-Just correlation) for both uncoated and Cr-coated claddings. Above the eutectic temperature at 1350$$^{circ}$$C, the fracture limit remained unchanged for Cr-coated claddings but decreased to 20% BJ ECR for uncoated claddings. This reduction is attributed to increased hydrogen uptake (up to $$sim$$500 wtppm), as confirmed by hydrogen analysis at the burst locations. The similar fracture limits of Cr-coated claddings below and above the eutectic temperature, further supported by metallographic observations and Vickers hardness measurements, suggest that the eutectic reaction did not appear to impact the fracture limit of Cr-coated claddings.

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