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Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Finsterle, S.*; Lanyon, B.*; 
kesson, M.*; Baxter, S.*; Bergstr
m, M.*; Bockg
rd, N.*; Dershowitz, W.*; Dessirier, B.*; Frampton, A.*; Fransson, .*; et al.
Geological Society, London, Special Publications, No.482, p.261 - 283, 2019/00
Times Cited Count：9 Percentile：70.92(Geology)Nuclear waste disposal in geological formations relies on a multi-barrier concept that includes engineered components which in many cases includes a bentonite buffer surrounding waste packages and the host rock. An SKB's (Swedish Nuclear Fuel and Waste Management Co.) Modelling Task Force project facilitated to improve the overall understanding of rock - bentonite interactions, as 11 teams used different conceptualisations and modelling tools to analyse the in-situ experiment at the 
ps Hard Rock Laboratory. The exercise helped identify conceptual uncertainties that led to different assessments of the relative importance of the engineered and natural barrier subsystems and of aspects that need to be better understood to arrive at reliable predictions of bentonite wetting.
Sawada, Atsushi; Saegusa, Hiromitsu; Takeuchi, Shinji*; Sakamoto, Kazuhiko*; Dershowitz, W. S.*
SKB P-13-46, 82 Pages, 2015/12
thermally induced phase separationSawada, Shinichi; Ursino, C.*; Galiano, F.*; Simone, S.*; Drioli, E.*; Figoli, A.*
Journal of Membrane Science, 493, p.232 - 242, 2015/11
Times Cited Count：53 Percentile：88.7(Engineering, Chemical)The replacement of commonly-used substances with non-toxic equivalents is attracting a great amount of attention in membrane preparation processes. In order to address this issue, we prepared porous poly(vinylidene fluoride) (PVDF) membranes via thermally-induced phase separation using the following non-toxic Citroflex as solvents: acetyl tributyl citrate (ATBC); acetyl triethyl citrate (ATEC); and triethyl citrate (TEC). The pore size of the membranes increased in the following solvent order of ATBC 
ATEC TEC, which is the same trend of the PVDF/solvent affinity. During the phase separation process, high-affinity solvent molecules should have enough molecular mobility and easily gather with each other to form the large solvent rich phases, thereby producing the large pores. In the pure water microfiltration test using the PVDF membranes, the water permeability can be controlled in the wide range, depending on the pore size.
collisions at 
= 200 GeVAdare, 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
Times Cited Count：29 Percentile：72.31(Astronomy & Astrophysics)We report on the event structure and double helicity asymmetry (
) of jet production in longitudinally polarized collisions at = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured = -0.0014 
0.0037 at the lowest 
bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various 
distributions.
collisions at = 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.44(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：8 Percentile：49.7(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
+ collisions at = 200 GeV and scaling properties of hadron productionAdare, 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
Times Cited Count：175 Percentile：98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of 
, 
, 
and 
mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, 
and 
, determining the high 
and characterizing the low regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
Yamaki, Tetsuya; Sawada, Shinichi; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru*; Gubler, L.*; Alkan G
rsel, S.*; Scherer, G. G.*
ECS Transactions, 25(1), p.1439 - 1450, 2009/10
Times Cited Count：4 Percentile：83.36(Electrochemistry)A multiply-crosslinked polymer electrolyte membrane was prepared by the radiation-induced co-grafting of styrene and a bis(vinyl phenyl)ethane (BVPE) crosslinker into a radiation-crosslinked polytetrafluoroethylene (cPTFE) film. We then investigated its hydrogen/oxygen fuel-cell performance at 60 and 80C in terms of the effect of radiation and chemical crosslinking. At 60C, all the membranes initially exhibited similar performance, but only the cPTFE-based membranes were durable at 80C, indicating the necessity of radiation crosslinking in the PTFE main chains. Importantly, cell performance of the multiply-crosslinked membrane was found high enough to reach that of a Nafion112 membrane. This is probably because the BVPE crosslinks in the graft component improved the membrane-electrode interface in addition to membrane durability. After severe OCV hold tests at 80 and 95C, the performance deteriorated, while no significant change was observed in ohmic resistivity. Accordingly, our membranes seemed so chemically stable that an influence on overall performance loss could be negligible.
Ben youcef, H.*; Gubler, L.*; Yamaki, Tetsuya; Sawada, Shinichi; Alkan Grsel, S.*; Wokaun, A.*; Scherer, G. G.*
Journal of the Electrochemical Society, 156(4), p.B532 - B539, 2009/02
Times Cited Count：16 Percentile：50.89(Electrochemistry)The effect of cross-linker content on the chemical stability of poly(ethylene-
-tetrafluoroethylene) (ETFE)-based radiation-grafted and sulfonated membranes was investigated. An ex situ degradation test in hydrogen peroxide solution showed a strong increase in stability of crosslinked membranes compared to uncrosslinked ones. Excessive crosslinking, however, is detrimental to the chemical and mechanical properties. Furthermore, the stability of grafted membranes based on ETFE was superior to those based on poly(tetrafluoroethylene-
-hexafluoropropylene) (FEP). An in situ long-term test in a hydrogen/oxygen single cell over 2180 h, using an ETFE-based grafted membrane optimized with respect to cross-linker content, with a graft level of 25% was carried out. The performance of the membrane electrode assembly exhibited a voltage decay rate of 13 
V/h over the testing time at a current density of 500 mA/cm
and a cell temperature of 80C, while the hydrogen permeation showed a steady increase over time. This indicates that, to some extent, changes in the membrane morphology occur over the operating period. Local postmortem analysis of the tested membrane reveals that high degradation was observed in areas adjacent to the oxygen inlet and in other areas nearby.
Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Sugimoto, Makoto; Isono, Takaaki; Kawano, Katsumi; Koizumi, Norikiyo; Hamada, Kazuya; et al.
IEEE Transactions on Applied Superconductivity, 9(2), p.628 - 631, 1999/06
Times Cited Count：8 Percentile：51.51(Engineering, Electrical & Electronic)no abstracts in English
Yamaki, Tetsuya; Sawada, Shinichi; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru; Gubler, L.*; Guersel, S. A.*; Scherer, G.*
no journal, ,
Multiply-crosslinked polymer electrolyte membranes were prepared by radiation-induced co-grafting of styrene and a bis(vinyl phenyl)ethane (BVPE) crosslinker into radiation-crosslinked polytetrafluoroethylene (cPTFE) films. We then investigated their hydrogen-oxygen PEFC performance at 60 and 80C in terms of the effect of radiation and chemical crosslinking. At 60C, all the membranes initially exhibited similar performance, but only the cPTFE-based membranes were durable at 80C, indicating necessity of radiation crosslinking in the PTFE main chains. Importantly, cell performance of the multiply-crosslinked membranes was found high enough to reach that of Nafion112. This is probably because the BVPE crosslinks in graft components improved the membrane-electrode interface in addition to membrane durability. After severe OCV hold tests at 80 and 95C, the performance deteriorated, while no significant change was observed in ohmic resistivity. Accordingly, our membranes seemed so stable that they could not have any serious influence on overall performance.
Yamaki, Tetsuya; Sawada, Shinichi; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru; Gubler, L.*; Alkan Grsel, S.*; Scherer, G.*
no journal, ,
Multiply-crosslinked polymer electrolyte membranes were prepared by radiation-induced co-grafting of styrene and a bis(vinyl phenyl)ethane (BVPE) crosslinker into radiation-crosslinked polytetrafluoroethylene (cPTFE) films. We then investigated their PEFC performance in terms of the effect of radiation and chemical crosslinking. Importantly, cell performance of the multiply-crosslinked membranes was found high enough to reach that of Nafion112. This is probably because the BVPE crosslinks in graft components improved the membrane-electrode interface in addition to membrane durability. After severe open circuit voltage hold tests, the performance deteriorated, while no significant change was observed in ohmic resistivity. Accordingly, our membranes seemed so stable that they could not have any serious influence on overall performance.
Sawada, Shinichi; Ulsino, C.*; Galiano, F.*; Simone, S.*; Drioli, E.*; Figoli, A.*
no journal, ,
The replacement of commonly-used substances with non-toxic equivalents is attracting a great amount of attention in membrane preparation processes. In order to address this issue, we prepared poly(vinylidene fluoride) (PVDF) flat membranes via a thermally-induced phase separation method using non-toxic citrate-based solvents: acetyl tributyl citrate (ATBC); acetyl triethyl citrate (ATEC); and triethyl citrate (TEC). The pore size of the prepared PVDF membranes depended on the type of used solvents, and increased in the following solvent order of ATBC ATEC TEC. This order is the same as that of the affinity with PVDF. In the case of the high affinity solvent, the solvent molecules would have high molecular mobility in a polymer solution and easily gather with each other to form the large size solvent-rich phases, which turn to the large pores in the prepared membranes.
