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上田 祐生; 小林 徹; 中村 聡志; 伴 康俊; 金田 結依; 生田目 望; Micheau, C.; 徳永 紘平; 中部 倫太郎; 金子 政志*; et al.
Langmuir, 42(1), p.1613 - 1626, 2026/01
溶媒抽出系における金属イオンの選択性を支配する構造要因の理解は、高レベル放射性廃棄物の分離変換プロセスを高度化する上で極めて重要である。本研究では、代表的なランタニドとしてランタン(La)とネオジム(Nd)を対象に、ニトリロトリアセトアミド(NTAamide)抽出剤のアルキル側鎖分岐度が抽出挙動に及ぼす影響を系統的に調査した。分子量は同一だがアルキル分岐度の異なる4種類の抽出剤(いずれもアミド鎖の1本が炭素数8)を用い、硝酸濃度に対する分配比を測定した。さらに、LaおよびNdの局所配位構造を拡張X線吸収微細構造(EXAFS)で解析し、有機相における超分子的凝集挙動を小角中性子散乱(SANS)で評価した。その結果、EXAFS解析から、LaおよびNdの内圏配位環境はアルキル分岐度の影響をほとんど受けないことが明らかとなった。一方、SANS解析からは、分岐の少ない抽出剤ほど低硝酸濃度で大きな凝集体を形成し、特にNdにおいては凝集体形成が抽出を促進し、難溶性錯体の沈殿を防いでいることが示された。これらの結果は、アルキル分岐度が超分子的凝集挙動を強く制御し、それが抽出挙動を支配していることを示している。本研究は、ランタニドおよびアクチニドの溶媒抽出において、選択性向上のための新しい設計概念として「ナノスケール構造制御」の可能性を示すものである。
柴田 基樹*; 竹中 幹人*; 元川 竜平; 熊田 高之; 上田 祐生; 宮崎 司*; 中西 洋平*; 阿部 淳*; 岩瀬 裕希*; 柴山 充弘*; et al.
Polymer, 340, p.129203_1 - 129203_7, 2025/12
The development of effective plastic degradation methods is crucial to address environmental pollution. Hydrothermal liquefaction using near-critical water is a promising technology, but the fundamental dissolution and decomposition mechanisms remain poorly understood. This study investigates the thermodynamics of a polystyrene (PS)/water system under near-critical conditions to elucidate this mechanism. We performed in situ small-angle neutron scattering (SANS) to observe the swelling of PS particles in deuterated water (D
O) at various temperatures under pressures of 10 MPa and 25 MPa. By applying the 
(FHS) theory to the swelling data, We quantitatively determined the Flory-Huggins interaction parameter as a function of temperature and pressure by applying the FHS theory to the swelling data. Based on these results, we constructed a phase diagram of the PS/DO system. The diagram reveals that miscibility increases with increasing pressure. This work provides a thermodynamical properties of water solutions of polymers under near-critical conditions for optimizing industrial hydrothermal recycling processes.
吉田 美里*; 新井 健悟*; 中川 大輝*; 堀川 喜樹*; 岩瀬 裕希*; 熊田 高之; 元川 竜平; 四方 俊之*
Biomacromolecules, 26(11), p.8332 - 8342, 2025/11
Structure and conformation of hydroxypropylmethyl cellulose (HpMC) samples (DS = 1.8 and MS = 0.15) with narrow molar mass distributions of Mw/Mn 
1.3 at Mw of 210, 310 and 440 kg/mol dissolved in aqueous solution were investigated using static light scattering (SLS) and small angle neutron scattering (SANS) techniques to cover a wide scattering vector (q) range. The q dependencies of the concentration-reduced excess Rayleigh ratios via SLS at the extrapolated zero-concentration were smoothly linked with those of the concentration reduced excess scattering intensities via SANS using the same factor for all the HpMC samples. The linked scattering intensity curves were reasonably described with the form factor of monodisperse rod particles. Moreover, broad interference scattering peaks possibly exist at q= 0.042 nm
in the linked scattering curves, suggesting the presence of a periodicity of ~150 nm in the rod-like particles formed by HpMC molecules.
戸田 賀奈子*; 元川 竜平; 斉藤 拓巳*
Journal of Physical Chemistry C, 11 Pages, 2025/08
被引用回数：0 パーセンタイル：0.00The development of the nano-scale pore size distribution of metakaolin-based geopolymers (MKGPs) was evaluated by the application of the small-angle neutron scattering (SANS), followed by the polydisperse spherical (PDSP) model application, where the modelled outputs were then deconvoluted by bimodal log-normal distribution fitting. Small pores, with a log-normal distribution modal value of 2.5 nm, immediately formed after mixing, with a decrement in the pore volume as a function of time. Larger pore size distribution with log-normal distribution modal values larger than 4nm, required an induction period, indicating the larger pore size distribution evolution corresponds to the pores as aluminosilicate cluster gel interstices. The nano-scale pore size distribution development varied by the curing temperature and the type of activators, which were evaluated in this study. The initial pore evolution of the MKGPs may be the critical step in determining the nano-sized porosity of the MKGPs, which characterizes the diffusive property of the material, such as the De of HDO.
-butadiene) reinforced by carbon blackWatanabe, Yuki*; 熊川 大幹*; Karitani, Shu*; 井上 正志*; 岩蕗 仁*; 中西 洋平*; 柴田 基樹*; 元川 竜平; 杉田 剛; 上田 祐生; et al.
Macromolecules, 58(16), p.8641 - 8648, 2025/08
被引用回数：0 パーセンタイル：0.00We investigated how the particle size of carbon black (CB) affects the reinforcement of CB to vulcanized poly(styrene-co-butadiene) (SBR) in the glassy region. When the average diameter of CB d is larger than 100 nm, the enhancement of modulus can be expressed by the Eshelby/Mori-Tanaka model, which agrees with the results obtained for an SBR/silica system. On the other hand, at d 100nm, the volume fraction dependence of the enhancement becomes stronger than the theory's prediction. The scattering studies on the SBR/CB systems revealed that the aggregates of CB at d 100nm consist of densely packed CB, while the aggregates of CB at d 
100nm exhibit branch structures. At d 100nm, the voids or the occluded region in the packed CB increase the volume fraction, resulting in a stronger volume fraction dependence of the enhancement.
上田 祐生; Micheau, C.; 元川 竜平
ファインケミカル, 54(5), p.53 - 60, 2025/05
持続可能な社会を実現するためには金属資源のリサイクルが重要である。高濃度の金属イオンを取り扱う抽出操作では、プロセスの安全な運転を阻害する油相の相分離(第三相の生成)が長年の課題であった。本稿では、フルオラス化合物の強力な疎水性を利用した、第三相を生成させない新たな抽出系開発におけるこれまでの成果をまとめた。
上田 祐生; Micheau, C.; 阿久津 和宏*; 徳永 紘平; 山田 雅子*; 山田 悟史*; Bourgeois, D.*; 元川 竜平
Langmuir, 40(46), p.24257 - 24271, 2024/11
被引用回数：1 パーセンタイル：15.56(Chemistry, Multidisciplinary)本研究では、パーフルオロヘキサン中のフルオラスリン酸エステル(TFP)からなるフルオラス抽出系において、n-ヘキサン中の有機リン酸エステル(THP)からなる類似の有機抽出系と比較して、より高い金属イオン抽出性能に寄与する主要因を分子レベルで理解するために、硝酸溶液からのZr(IV)イオンの抽出の巨視的挙動を微視的構造情報と相関させた。拡張X線吸収微細構造、中性子反射率測定、中性子小角散乱により、それぞれZr(IV)イオン周辺の局所配位構造、界面における抽出剤分子の蓄積、バルク抽出相における抽出剤分子の構造が明らかになった。その結果、いずれの抽出系においても、界面には抽出剤分子はあまり蓄積しなかった。フルオラス抽出系では、硝酸との接触により凝集体が形成され、Zr(IV)抽出後も残存した。一方、有機抽出系では、二量体のみが形成された。Zr(IV)イオン周辺の局所的な配位構造とバルク抽出相における抽出剤分子の構造の違いが、フルオラス抽出系における高いZr(IV)抽出性能に寄与していると推測している。特に、フルオラス相中のZr(IV)濃度が増加しても凝集体の大きさはほとんど変化せず、これはフルオラス抽出系で相分離が起こらないことと密接に関係していると考えられる。
南川 卓也
化学, 79(8), p.48 - 52, 2024/08
漆は、耐水性・耐薬品性に優れた稀有な天然塗料である。生漆にごく微量の鉄を加えると、非常に美しい漆黒が作り出されることが古くから知られている。しかし現代でも漆の構造や反応はほとんど解明されておらず、鉄を加えると何故黒色になるかも明らかにされていない。本研究では、黒漆が黒色になる原因を性質の異なる量子ビームを用いることで分析した。その結果、黒漆は生漆と全く違うナノ構造を持ち、その構造の違いで色が変化することが明らかになった。この結果は、長年にわたって謎であった漆膜の構造解析が初めて成功した結果である。本解説では、この研究を解説するとともに、化学系の大学生を対象にしているため、この研究がどのように進められてきたのかなども説明するものである。
山崎 大; 丸山 龍治; 青木 裕之; 花島 隆泰*; 阿久津 和宏*; 宮田 登*; 曽山 和彦
Quantum Beam Science (Internet), 9(2), p.20_1 - 20_12, 2024/06
This study developed a neutron-beam focusing supermirror for grazing-incidence small-angle neutron scattering (GISANS) measurements. It was fabricated by depositing NiC/Ti supermirror film with ion-beam sputtering on a precise elliptic surface of fused quartz figured using the elastic emission machining technique. Neutron measurements at a pulsed neutron reflectometer BL17 of MLF, J-PARC successfully demonstrated that the focusing supermirror enhances a beam intensity twentyfold compared with an optimally collimated beam, achieving the signal-to-background ratio of the focal spot as high as 500. The mirror can be readily installed and used at BL17.
坂口 佳史*; 高田 慎一; 川北 至信; 藤村 由希; 近藤 啓悦
Journal of Physics; Condensed Matter, 35(41), p.415403_1 - 415403_11, 2023/10
被引用回数：1 パーセンタイル：7.26(Physics, Condensed Matter)It is well-known that eutectic gold-silicon (Au-Si) alloys exhibit anomalous melting point depression, which is more than 1000 
C from the melting point of elemental Si (1414 C). The melting point depression in eutectic alloys is generally explained in terms of a decrease of the free energy by mixing. However, it is difficult to understand the anomalous melting point depression only from the stability of the homogeneous mixing. Some researchers suggest that there are concentration fluctuations in the liquids, where the atoms are inhomogeneously mixed. In this paper, we measure the small-angle neutron scattering (SANS) of Au
Si
(eutectic composition) and Au
Si
(off-eutectic composition) at temperatures from room temperature to 900 C in both solid and liquid states to observe such concentration fluctuations directly.
大平 征史*; 片島 拓弥*; 内藤 瑞*; 青木 大輔*; 吉川 祐介*; 岩瀬 裕希*; 高田 慎一; 宮田 完二郎*; Chung, U.-I.*; 酒井 崇匡*; et al.
Advanced Materials, 34(13), p.2108818_1 - 2108818_9, 2022/01
被引用回数：27 パーセンタイル：89.26(Chemistry, Multidisciplinary)DNA duplexes are ideal crosslinkers for building such gels because of their excellent sequence addressability and flexible tunability in bond energy. However, the mechanical responses of most DNA gels are complicated and unpredictable. The melting curve analysis of the DNA gels reveals the good correspondence between the thermodynamic potentials of the DNA crosslinkers and the presimulated values by DNA calculators. Stress-relaxation tests and dissociation kinetics measurements show that the macroscopic relaxation time of the DNA gels is approximately equal to the lifetime of the DNA crosslinkers over 4 orders of magnitude from 0.1-2000 s. Furthermore, a series of durability tests find the DNA gels are hysteresis-less and self-healable after the applications of repeated temperature and mechanical stimuli.
長尾 道弘*; Kelley, E. G.*; Faraone, A.*; 齋藤 真器名*; 依田 芳卓*; 黒葛 真行*; 高田 慎一; 瀬戸 誠*; Butler, P. D.*
Physical Review Letters, 127(7), p.078102_1 - 078102_7, 2021/08
被引用回数：27 パーセンタイル：84.93(Physics, Multidisciplinary)Membrane viscosity is a fundamental property that controls molecular transport and structural rearrangements in lipid membranes. Given its importance in many cell processes, various experimental and computational methods have been developed to measure the membrane viscosity, yet the estimated values depend highly on the method and vary by orders of magnitude. Here we investigate the molecular origins of membrane viscosity by measuring the nanoscale dynamics of the lipid acyl tails using X-ray and neutron spectroscopy techniques. The results show that the membrane viscosity can be estimated from the structural relaxation times of the lipid tails.
原田 雅史*; 高田 慎一; 岩瀬 裕希*; 梶谷 修司*; 門浦 弘明*; 金谷 利治*
ACS Omega (Internet), 6(23), p.15257 - 15263, 2021/06
被引用回数：28 パーセンタイル：80.67(Chemistry, Multidisciplinary)The ionomers distributed on carbon particles in the catalyst layer of polymer electrolyte fuel cells (PEFCs) govern electrical power via proton transport and oxygen permeation to active platinum. Thus, ionomer distribution is a key, to PEFC performance. This distribution is characterized by ionomer adsorption and deposition onto carbon during the catalyst-ink coating process; however, the adsorbed and deposited ionomers cannot easily be distinguished in the catalyst layer. Therefore, we identified these two types of ionomers based on the positional correlation between the ionomer and carbon Particles. From fitting with a model for a fractal aggregate of polydisperse core-shell spheres we determined the adsorbed-ionomer thickness on the carbon particle to be 51 angstrom land the deposited-ionomer amount for the total ionomer to be 50%. Our technique for ionomer differentiation can be used to optimally design PEFC catalyst layers.
Kumar, S.*; Saha, D.*; 高田 慎一; Aswal, V. K.*; 瀬戸 秀紀
Applied Physics Letters, 118(15), p.153701_1 - 153701_7, 2021/04
被引用回数：9 パーセンタイル：53.85(Physics, Applied)We report the pathways to suppress or enhance the protein adsorption on nanoparticles and thereby control the stability of the nanoparticle-protein complexes with the help of selective additives. This has been achieved by tuning the electrostatic interaction between the nanoparticles and proteins, in the presence of surfactant and multivalent counterions. The preferential binding of the proteins with the surfactant and multivalent ions induced charge reversibility of nanoparticles can lead to adsorption of an otherwise non-adsorbing protein and vice versa. The findings are demonstrated for anionic silica nanoparticles and two globular proteins [lysozyme (cationic) and bovine serum albumin (BSA) (anionic)] as model systems, in the presence of two ionic surfactants [anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB)], and ZrCl
as multivalent salt.
Pallbo, J.*; 今井 正幸*; Gentile, L.*; 高田 慎一; Olsson, U.*; Sparr, E.*
Frontiers in Physiology (Internet), 11, p.592117_1 - 592117_13, 2020/12
被引用回数：8 パーセンタイル：36.96(Physiology)In this paper we investigate interactions between an aggregating peptide and phospholipid membranes, focusing on the nanometer-scale structures of the aggregates formed, as well as on the effect on the aggregation process. As a model system, we use the small amyloid-forming peptide named NACore, which is a fragment of the central region of the protein alpha-synuclein that is associated with Parkinson's disease. We find that phospholipid vesicles readily associate with the amyloid fibril network in the form of highly distorted and trapped vesicles that also may wet the surface of the fibrils.
Singh, H.*; Ray, D.*; Kumar, S.*; 高田 慎一; Aswal, V. K.*; 瀬戸 秀紀
Physical Review E, 102(6), p.062601_1 - 062601_11, 2020/12
被引用回数：13 パーセンタイル：70.59(Physics, Fluids & Plasmas)The interaction of nanoparticles with surfactants is extensively used in a wide range of applications from enhancing colloidal stability to phase separation processes as well as in the synthesis of noble functional materials. The interaction is highly specific depending on the charged nature of the surfactant. In the case of nonionic surfactants, the micelles adsorb on the surface of nanoparticles. The adsorption of nonionic surfactant C12E10 as a function of surfactant concentration for two different sizes of anionic silica nanoparticles (16 and 27 nm) has been examined using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The study on different-sized nanoparticles shows that the lower curvature enhances the packing fraction whereas the loss of surface-to-volume ratio suppresses the fraction of adsorbed micelles with the increase in the nanoparticle size.
野田 昂志*; 土肥 侑也*; 太田 豊*; 高田 慎一; 高野 敦志*; 松下 裕秀*
Journal of Polymer Science, 58(15), p.2098 - 2107, 2020/08
被引用回数：10 パーセンタイル：31.61(Polymer Science)A four-branched cage-shaped poly(ethylene oxide) (4C-PEO) was prepared by a coupling reaction at very dilute condition between two kinds of end-functional four-armed star-shaped PEOs having amino and 
-hydroxysuccinimide groups on their four ends, followed by purification using 
-cyclodextrin (-CD). The raw coupling reaction product shows multiple peaks including various high molecular weight multimeric products in size-exclusion chromatography measurements, while the product after -CD purification shows a single peak eluted slightly earlier than the precursor star PEOs. These results suggest that the targeted 4C-PEO polymer was successfully isolated through the -CD purification. Small-angle neutron scattering (SANS) measurements of the final product in dilute solution were conducted, and its chain conformation was evaluated from the scattering profile in comparison with linear and star polymers.
Gupit, C. I.*; Li, X.*; Maekawa, Ryosuke*; Hasegawa, Naoki*; 岩瀬 裕希*; 高田 慎一; 柴山 充弘*
Macromolecules, 53(4), p.1464 - 1473, 2020/02
被引用回数：25 パーセンタイル：70.55(Polymer Science)The present work involved a systematic analysis of both the structural and rheological properties of Nafion dispersions carefully prepared using a standard procedure, ranging from dilute (0.1 wt %) to highly concentrated (30 wt %) conditions. Small-angle X-ray scattering confirmed the cylindrical structure of Nafion in dispersion and the unique interactions of Nafion particles acting as polyelectrolytes. Three different scaling relationships involving the zero-shear viscosities of the Nafion dispersions were determined for specific concentration regimes. However, at the upper concentration limit of approximately 30 wt %, the viscosity greatly deviated from these scaling relationships and significant shear thinning was observed. Simultaneous analyses using rheology and small-angle neutron scattering determined fully isotropic spatial correlations on a length scale of less than 60 nm, even when high shear was applied.
-lactoglobulin吉田 亨次*; 禪院 知寛*; Fujiyoshi, Ayako*; 真田 雄介*; 山口 敏男*; Murata, Kunihiko*; 高田 慎一; 廣井 孝介; 竹清 貴浩*; 吉村 幸浩*
Journal of Molecular Liquids, 293, p.111477_1 - 111477_9, 2019/11
被引用回数：9 パーセンタイル：39.16(Chemistry, Physical)Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS) measurements, and scanning and transmission electron microscope (SEM and TEM) of -lactoglobulin (-LG) are performed in alkyl (methyl, ethyl, and propyl) ammonium nitrate ionic liquids (RAN-ILs)-water mixtures at 25-100C. The addition of these RANs decreased the thermal denaturation temperature of -LG, and the effect is larger with an increase of the hydrophobic part of the cation of the ILs. In ethyl ammonium nitrate (EAN) and propyl ammonium nitrate (PAN) mixtures, the fractal aggregate structure of -LG was found after the thermal denaturation occurred. These results are similar to those of alcohol-water mixtures. The nanoheterogeneous structure of the RAN-water mixture which consists of the hydrophobic and hydrophilic parts might affect the aggregation structure of -LG.
金子 文俊*; 河口 達也*; Radulescu, A.*; 岩瀬 裕希*; 森川 利明*; 高田 慎一; 西浦 正芳*; Hou, Z.*
Review of Scientific Instruments, 90(9), p.093906_1 - 093906_6, 2019/09
被引用回数：6 パーセンタイル：31.34(Instruments & Instrumentation)Small angle neutron scattering (SANS) is a versatile and convenient method to investigate the higher order structure of molecular assembly systems. However, the more complicated a system of interest, the more difficult the interpretation in the SANS profile. In order to increase the reliability of structural analysis on a complicated system, it is desirable to obtain different kinds of structural information from the same sample simultaneously. Polarized infrared spectroscopy is able to provide information about the molecular structure, concentration, and orientation of each chemical species in a system. In order to utilize these advantages of polarized infrared spectroscopy, a simultaneous measurement system was built by incorporating a Fourier transform infrared (FTIR) spectrometer into a time-of-flight small angle neutron scattering instrument covering a wide Q range.
