Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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：0 パーセンタイル：0.00(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。
Micheau, C.; 上田 祐生; 元川 竜平; 阿久津 和宏*; 山田 悟史*; 山田 雅子*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.
Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05
被引用回数：1 パーセンタイル：65.37(Chemistry, Physical)Supramolecular organization of amphiphilic extractant molecules is involved in metal cation selectivity and separation kinetics during solvent extraction. The relationship between extractant associates/aggregates formed in the organic bulk phase and at the liquid-liquid interface is poorly understood even though it affects the extraction mechanism. The nanoscopic structures of the extraction systems N,N,N',N'-tetrahexylmalonamide (THMA) in toluene and N,N'-dibutyl-N,N'-dimethyl-2-tetradecylmalonamide (DBMA) in n-heptane, used for either Pd(II) or Nd(III) selective extraction from an acidic aqueous phase, were examined. These systems present markedly different affinity for Pd(II) and Nd(III), and extraction kinetics. Extractant organization in the organic bulk phase and at the interface were compared by small-angle X-ray scattering, interfacial tension, and neutron reflectivity. THMA in toluene forms small associates in the organic bulk phase and accumulates in a diffuse layer at the interface, decreasing Pd(II) coordination probability and resulting in slow extraction. DBMA in n-heptane forms large aggregates and a compact, dense interfacial layer, resulting in rapid Pd(II) and Nd(III) extraction. Thus, Pd(II) extraction is driven by interfacial coordination alone, whereas the incorporation of Nd(III) into the core of large aggregates governs Nd(III) extraction in the interfacial layer. These results suggest that the interface should be described as a nanoscale interphase containing a high extractant concentration compared with the organic bulk phase.
Micheau, C.; 上田 祐生; 阿久津 和宏*; Bourgeois, D.*; 元川 竜平
Solvent Extraction and Ion Exchange, 41(2), p.221 - 240, 2023/02
被引用回数：4 パーセンタイル：56.38(Chemistry, Multidisciplinary)Malonamide derivatives, which are among the most extensively investigated extractants in solvent extraction of lanthanoids, actinides, and platinum group metal ions, were deuterated by using Pd/C and Rh/C catalysts with a D
O/2-propanol mixture. This method enables to replace the hydrogen atoms by deuterium atoms in the malonamide chemical structure with a controllable deuteration rate. The maximum rate reaches 75 percent approximately, determined by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry. In addition, it has been demonstrated that extraction behavior of the malonamide molecules remains unchanged after the deuteration procedure. Deuterated malonamides should be a powerful tool for fundamental researches on solvent extraction systems, in particular, for structural analysis of the organic phases. The large difference in the neutron scattering cross-section between hydrogen and deuterium leads to a large difference in neutron scattering length density of the malonamide derivatives before and after the deuteration reaction. Therefore, using deuterated malonamides in small-angle neutron scattering and neutron reflectivity studies could give access to the nanoscopic structure of the specific solute species in the bulk organic phase and at the liquid-liquid interface, respectively. This deuteration method could become a general one and be extended to a wide variety of extractant molecules. In this way this work contributes to the development of the fundamental researches in solvent extraction systems.
Faenov, A. Y.; Magunov, A. I.*; Pikuz, T. A.*; Skobelev, I. Y.*; Giulietti, D.*; Betti, S.*; Galimberti, M.*; Gamucci, A.*; Giulietti, A.*; Gizzi, L. A.*; et al.
JETP Letters, 86(3), p.178 - 183, 2007/08
被引用回数：5 パーセンタイル：36.87(Physics, Multidisciplinary)X-ray spectroscopy diagnostics of laser-cluster interactions at a stage of non-adiabatical cluster expansion and formation of the spatially homogeneous plasma channel is carried out for the first time. It is shown, that X-ray line emission spectra of light elements, allows to determine parameters of the plasma formed at the time moment 10 ps from the beginning of femtosecond laser with relatively high plasma temperature Te 100 eV iand electron density Ne about 10
- 10
cm
.
shell gap in 
NeBelleguic, M.*; Azaiez, F.*; Dombr
di, Zs.*; Sohler, D.*; Lopez-Jimenez, M. J.*; 大塚 孝治*; Saint-Laurent, M. G.*; Sorlin, O.*; Stanoiu, C.*; 宇都野 穣; et al.
Physical Review C, 72(5), p.054316_1 - 054316_7, 2005/11
被引用回数：42 パーセンタイル：89.58(Physics, Nuclear)原子核の殻構造が不安定核で変化する可能性が指摘されているが、その是非を明らかにするにはいわゆる侵入者状態の励起エネルギーを系統的に調べることが必要である。この論文では、GANIL研究所で不安定核
Neの新たな準位を見つけ、その結果を原研らのグループによってなされたモンテカルロ殻模型計算の結果と比較したものである。これらの不安定核を
S
ビームの入射核破砕反応によって生成し、脱励起
線を観測することにより、新しい準位を見つけた。
Neにおいては、観測された準位は
殻を仮定した殻模型計算の結果とよく一致し、低励起状態において侵入者状態は見つからなかった。一方、この実験で新たに見つかった
Neにおける2.24MeVの状態は、旧来の殻模型で対応するものが存在しないため、侵入者状態が支配的と考えられる。実際、モンテカルロ殻模型計算によって2.2MeV付近にこのような
状態があると予言される。この実験で得られたN=18核における非常に低い状態の存在は、不安定核においてN=20の殻ギャップが非常に狭まっていなくては説明できず、不安定核で魔法数が消滅するメカニズムの解明に大きな知見を与えるものである。
元川 竜平; 上田 祐生; Micheau, C.; Bourgeois, D.*; Dourdain, S.*; Diat, O.*
no journal, ,
Neutron scattering is a useful complement to X-ray scattering each other in the study of material structures, mainly because the neutron cross-section varies randomly among elements, whereas the X-ray atomic scattering factor increases with atomic number. The large difference in the scattering cross-section between hydrogen and deuterium is crucial in the use of neutron scattering to analyze the microscopic structure of various materials, so that the difference enables us to observe only the structures formed by one specific component among scatterers composed of other multiple components. Recently, we have developed small-angle neutron scattering diffractometer (SANS-J), at JRR-3 of the Japan Atomic Energy Agency, Japan, and the various kinds of studies in chemical separation systems, such as biphasic solvent extraction, flotation process, and solids-liquid separation using adsorbent materials, which are well related to the nuclear process, have been conducted in the place. Here we will present our small-angle scattering diffractometer, SANS-J, which is a typical apparatus installed at the research reactor for neutron scattering, as well as some representative results obtained. We discuss the collaborative research with French institutions not limited to solvent extraction systems.
Micheau, C.; 元川 竜平; 上田 祐生; 阿久津 和宏*; 山田 悟史*; 山田 雅子*; Bourgeois, D.*; Berthon, L.*
no journal, ,
DIAMEX process uses malonamide molecules for the separation and co-extraction of actinides and lanthanides from the raffinate of the PUREX process. Recent study on the use of malonamide molecules for the extraction and separation of PdII and NdIII by solvent extraction has pointed out two main driving forces that could explain the selectivity. Coordination and extractant aggregation. It has been demonstrated that Pd only needs coordination to be extracted whereas Nd needs in addition the aggregation of the extractant. Extractant aggregation can be beneficial for solvent extraction process if it can be controlled to enhance separation. In order to confirm a potential correlation between the separation efficiency and the extractant aggregation, a model malonamide molecule was investigated. This extractant was dissolved, at room temperature, in pure n-heptane, pure toluene, and mixtures of both solvents at different ratios, and contacted with different nitric acid solutions with and without metal ions. These two solvents possess different relative permittivity, and topology with an aromatic ring for toluene that could lead to additional pi-interaction with the extractant. Distribution ratios of Pd and Nd, as well as separation factors were determined. In parallel, small angle neutron scattering technique was used to determine the size and shape of the aggregates formed. From these results, it can be said that heptane promotes the formation of large assemblies, whereas the presence of toluene tends to reduce the size of the assemblies which was directly correlated to extraction separation efficiency.
Micheau, C.; 上田 祐生; 元川 竜平; Moussaoui, S.*; Makombe, E.*; Daniel, M.*; Berthon, L.*; Bourgeois, D.*; 阿久津 和宏*
no journal, ,
The DIAMEX process aims to separate minor f-elements using malonamide as extractant molecules such as N,N'-dimethyl-N,N'-dibutyl-tetradecyl-malonamide (DBMA). Recently, Poirot studied the effect of n-heptane and toluene on the selectivity of DBMA between Pd and Nd and have conclude that Pd extraction is driven by coordination whereas Nd extraction is driven by extractant aggregation. More recently, a specific study on tetrahexylmalonamide (THMA) in toluene demonstrated a superior selectivity for Pd compared to DBMA. THMA molecular structure suggests poor aptitude for aggregation compared with DBMA, and has been much less characterized. Supramolecular features of two different solvent extraction systems based on malonamide extractants, THMA in toluene and DBMA in heptane, have been studied using characterization techniques dedicated to bulk organic phase organisation, ie. small angle X-ray scattering, and to interface characterization, ie. neutron reflectivity and interfacial tension.
