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日本原子力研究開発機構(JAEA)廃炉環境国際共同研究センター(CLADS)では、令和2年度英知を結集した原子力科学技術・人材育成推進事業(以下、「本事業」という)を実施している。本事業は、東京電力ホールディングス株式会社福島第一原子力発電所の廃炉等をはじめとした原子力分野の課題解決に貢献するため、国内外の英知を結集し、様々な分野の知見や経験を、従前の機関や分野の壁を越えて緊密に融合・連携させた基礎的・基盤的研究及び人材育成を推進することを目的としている。平成30年度の新規採択課題から実施主体を文部科学省からJAEAに移行することで、JAEAとアカデミアとの連携を強化し、廃炉に資する中長期的な研究開発・人材育成をより安定的かつ継続的に実施する体制を構築した。本研究は、研究課題のうち、平成30年度に採択された「放射性核種の長期安定化を指向した使用済みゼオライト焼結固化技術の開発」の平成30年度から令和3年度の研究成果について取りまとめたものである(令和3年度まで契約延長)。本課題は令和3年度が最終年度となるため4年度分の成果を取りまとめた。本研究は、継続して発生するCs等の放射性核種を吸着したゼオライト(使用済みIE-96)にガラスをバインダーとして添加し、それらを焼結することで核種を固定化する新たな焼結固化法の開発を目的とする。本研究では、コールド試験により焼結固化の最適条件および焼結固化体の基礎性能を評価し、ホット試験でそれらを実証する。令和2年度において、最適化された条件で作製した焼結固化体は、優れた化学的安定性を有することをコールド試験で明らかにした。また、ホット試験において焼結固化体は、優れた化学的安定性を有することを実証した。さらに、ホット試験において焼結固化作製におけるCsの揮発率はわずかであることを確認した。焼結固化法のプロセスフロー、機器装置、仕様等を示した。また、焼結固化法の各種データを他の固化法と比較して評価し、焼結固化法に優位性があることを確認した。, The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science \& Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of the sintering solidification method for spent zeolite to long-term stabilization" conducted from FY2018 to FY2021 (this contract was extended to FY2021). Since the final year of this proposal was FY2021, the results for four fiscal years were summarized. The present study aims to develop a new sintering solidification method in which glass is added as a binder to spent zeolite which is adsorbed radionuclides such as Cs and the nuclides are immobilized by sintering them. In this project, the optimum conditions for sintering solidification and the basic performance of the sintered solidified body will be evaluated by cold tests, and they will be demonstrated by hot tests. In FY2020, the cold tests

日本原子力研究開発機構(JAEA)廃炉環境国際共同研究センター(CLADS)では、令和元年度英知を結集した原子力科学技術・人材育成推進事業(以下、「本事業」という)を実施している。本事業は、東京電力ホールディングス福島第一原子力発電所の廃炉等をはじめとした原子力分野の課題解決に貢献するため、国内外の英知を結集し、様々な分野の知見や経験を、従前の機関や分野の壁を越えて緊密に融合・連携させた基礎的・基盤的研究及び人材育成を推進することを目的としている。平成30年度の新規採択課題から実施主体を文部科学省からJAEAに移行することで、JAEAとアカデミアとの連携を強化し、廃炉に資する中長期的な研究開発・人材育成をより安定的かつ継続的に実施する体制を構築した。本研究は、研究課題のうち、平成30年度に採択された「放射性核種の長期安定化を指向した使用済みゼオライト焼結固化技術の開発」の令和元年度の研究成果について取りまとめたものである。本研究は、継続して発生するCs等の放射性核種を吸着したゼオライト(使用済みゼオライト)の焼結固化法の開発を目的とする。焼結固化法は、使用済みゼオライトにガラスをバインダーとして添加し、それらを焼結することで核種を固定化する新たな固化法である。本法は、ガラス固化と比較して固化体の大幅な減容や焼成固化と同程度の安定な固化体の形成が期待できる。本事業では、コールド試験により焼結固化に適したガラスの選定、焼結温度等の最適化を図りホット試験で実証する。令和元年度において使用済みゼオライトの焼結固化用バインダーとしてB$_{2}$O$_{3}$系ガラスを選定し、焼結固化条件の最適化を図った。また、模擬汚染水として照射済み燃料に由来する核種を含む水を調製し、IE-96に吸着させることにより模擬使用済みIE-96を作製した。さらに、ゼオライトの固化,焼成固化等に関する既存の研究成果及び最新の研究動向を調査し、焼結固化プロセスの概念を設計した。, JAEA/CLADS had been conducting the Nuclear Energy Science \& Technology and Human Resource Development Project. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of the Sintering Solidification Method for Spent Zeolite to Long-term Stabilization" conducted in FY2019.

日本原子力研究開発機構(JAEA)廃炉国際共同研究センター(CLADS)では、平成30年度英知を結集した原子力科学技術・人材育成推進事業(以下、「本事業」という)を実施している。本事業は、東京電力ホールディングス福島第一原子力発電所の廃炉等をはじめとした原子力分野の課題解決に貢献するため、国内外の英知を結集し、様々な分野の知見や経験を、従前の機関や分野の壁を越えて緊密に融合・連携させた基礎的・基盤的研究及び人材育成を推進することを目的としている。平成30年度の新規採択課題から実施主体を文部科学省からJAEAに移行することで、JAEAとアカデミアとの連携を強化し、廃炉に資する中長期的な研究開発・人材育成をより安定的かつ継続的に実施する体制を構築した。本研究は、研究課題のうち、平成30年度「放射性核種の長期安定化を指向した使用済みゼオライト焼結固化技術の開発」について取りまとめたものである。本研究は、継続して発生するCs等の放射性核種を吸着したゼオライト(使用済みゼオライト)の焼結固化法の開発を目的とする。焼結固化法は、使用済みゼオライトにガラスをバインダーとして添加し、それらを焼結することで核種を固定化する新たな固化法である。本法は、ガラス固化と比較して固化体の大幅な減容や焼成固化と同程度の安定な固化体の形成が期待できる。本事業では、コールド試験により焼結固化に適したガラスの選定、焼結温度等の最適化を図りホット試験で実証する。平成30年度においてバインダーの候補ガラスの熱特性、及び加熱雰囲気が焼結固化に及ぼす影響について調査した。また、放射性核種を含む模擬汚染水を作成するための照射済燃料を選定し、試料の状態を確認した。さらに、ゼオライトの固化、焼成固化等に関する既存の研究成果及び最新の研究動向を調査した。, JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of the Sintering Solidification Method for Spent Zeolite to Long-term Stabilization". The present study aims to develop the sintering solidification method for zeolites (spent zeolites) that adsorbs continuously generated radionuclides such as cesium. The sintering solidification method is able to stabilize adsorbed radionuclides such as cesium in zeolites by adding a glass as a binder to spent zeolite and sintered it. It is expected that the sintering solidification method is significantly reduce the volume of the solidified body compare with the glass solidification method and to form a stable solidified body equivalent to the calcination solidification method. In this project, we planned to select a glass suitable for the sintering solidification method and optimize the sintering temperature, etc. using non-radioactive nuclides (cold tests), and verify it by using radioactive nuclides (hot tests). In FY2018, we investigated the thermal properties of candidate glasses for binder and the effect of heating atmosphere on the sintering solidification method. Irradiated fuel for preparing simulated contaminated water containing radionuclides was selected and the condition of it was observed. In addition, we surveyed existing research results and latest research trends about solidification of zeolite, calcination solidification and so on.

In the present paper, we calculated the occurrence probabilities of the third year branching pattern models of two Psychotria species (Psychotria rubra and Psychotria manillensis) on Okinawa Island. As the results of our calculation, we found that some particular models had higher probabilities for P.rubra. On the other hand, the differences among the probabilities of the models for P.manillensis were small., 本稿では沖縄島に生育するボチョウジ属2種（ボチョウジとナガミボチョウジ）に対しての3年目の分枝発生モデル157個の生起確率を計算した．その結果、ポチョウジは特定のモデルが高い確率を有していたのに対し、ナガミボチョウジはそれぞれのモデルの確率の差が小さいことがわかった．

Angiogenesis is the formation of new microvessels by endothelialcell migration and proliferation from preexisting vessels. This process is essentialfor numerous physiological events such as embryonic development, ovulation,and wound healing. Angiogenesis is also beneficial in tissue recovery byreperfusion of ischemic tissue but is maladaptive for arteriosclerosis, diabetes andtumor growth. It is therefore important to be able to control angiogenesis. In vitroexperiments have significantly advanced our understanding of angiogenesis.Many kinds of in vitro angiogenesis models have been designed to study theeffects of angiogenesis regulators（e.g. growth factors）. We have assessed theeffect of shear stress and extracellular matrix on angiogenesis using several invitro models. Our results reveal that these factors affect properties of endothelialcells in angiogenesis and each model has a future prospect relating to thedirection of each specific study.

International audience; In this paper, two main superconducting compounds have been studied: • The first study was focused on the preparation of magnesium diboride (MgB2) cryo-magnets by Spark Plasma Sintering (SPS). The role of the starting powder on the superconducting properties of MgB2 is investigated. Different sets of bulk MgB2 material were processed from: (i) a commercial available powder, (ii) a mixture of Mg metal and amorphous B using a single-step solid-state reaction process and (iii) a mixture of amorphous boron coated with carbon and Mg metal. The samples were prepared in tungsten carbide moulds varying the processing conditions by the modulation of the temperature, the dwell time and the applied pressure. The microstructures of the samples were investigated by SEM and TEM and correlated to their superconducting properties. The best sample was prepared at 850°C, 20 min and 100 MPa. At 20 K its critical current density (Jc) was 500 kA/cm2. Here in, we demonstrate that MgB2 is an excellent candidate to make cryo-magnets, maintaining 3.9 T at 20 K at the surface of a 20 mm diameter disk.• The SPS was modified with the aim of obtaining textured lamellar compounds with Bi2Ca2Sr2CuO8 superconductor ceramics. The new process is referred to as “Spark Plasma Texturing” (SPT). During SPT, the bulk material can freely deform itself. As a result, the formation of an inter-grain preferential crystallographic orientation is favoured. The superconducting properties were measured and discussed in correlation with textured microstructure analysis.

International audience; Racemic and optically active 3-(2-deuteriophenyl)-2-(1-phenylpropan-2-yl)quinazoline-4-thiones were prepared. The nuclear magnetic resonance spectra clearly show that they exist as a 1:1 mixture of diastereomers due to the isotopic atropisomerism based on ortho-H/D discrimination (N-C axial chirality) and a chiral carbon.

International audience; MgB2 pellets that were sintered by Spark Plasma Sintering (SPS) from commercial MgB2 powder were soldered by a SPS process and compared to unsoldered ones. The soldered samples were characterized by scanning and transmission electron microscopy which have shown no visible defects at the junction. SQUID magnetometry and four probes resistance measurements have confirmed that the soldered pellets present the same magnetic properties as the unsoldered ones. The presented soldering technique could find applications for manufacturing superconducting devices with custom shapes which could be used as rotors for motors and generators, magnets and magnetic shields. This new approach could generate a high potential interest for industrials in these and connected domains such as the development of new electrical planes using superconducting technologies.

Highly dense bulk MgB2 samples have been elaborated by unconventional "Spark Plasma Sintering" (SPS) according to different processing routes using conventional graphite dies or tungsten carbide dies. Different precursors were used: i) the commercial powder MgB2 ii) mixtures of magnesium and nano boron powder (Mg + 2B) iii) mixtures of Mg and MgB4 powder and iv) mixtures of magnesium and carbon-encapsulated boron powder (Mg+2B/C) for an "in-situ" reactive synthesis. The density of the obtained MgB2 bulks was up to 99 % of the theoretical density of the material, which is the highest so far reported in literature. Then structural and microstructural characterizations were carried out with these samples and correlated to their superconducting properties, in particular their critical current densities, Jc measured at 20 K. The optimized heat treatment for the in-situ MgB2 bulks was found to be lower than 800°C under 300 MPa pressure. A high Jc = 675 kA/cm2 was obtained in self-field and remarkably for an un-doped bulk MgB2, Jc was above 10 kA/cm2 at 4 T. A moderate Mg addition in the samples sintered at high temperatures (>900°C) can suppress the Mg-depleted phases (MgB4) and improve the intergrain connectivity and consequently, the critical current density Jc at low fields. Substitution of boron by carbon depresses slightly critical temperature, Tc but enhances vortex pinning, with the result of optimized performances of Jc in high field (around 10 kA/cm2 at 5 T and 20 K) with the mixtures containing carbon-coated boron or nano SiC doping. In addition, the functional properties have been investigated for large bulks fabricated with the commercial MgB2 powder, especially the levitation and restoring forces in superconducting magnetic levitation (SML) as well as the trapped field. These measurements have revealed that large diameter MgB2 discs can be good candidates for SML systems using a cryogenic fluid such as hydrogen or neon.; Des massifs MgB2 ont été préparés par frittage rapide "Spark Plasma Sintering " (SPS) selon différentes voies de traitement utilisant des moules en graphite conventionnelles ou des moules en carbure de tungstène. Différents précurseurs ont été utilisés : i) la poudre commerciale MgB2 ii) mélange de poudre de magnésium et de nano bore (Mg + 2B) iii) mélange de poudre de Mg et MgB4 et iv) mélange de poudre de magnésium et de bore enrobée du carbone (Mg+2B/C) pour une synthèse réactive "in-situ". La densité des échantillons obtenus était jusqu’à 99 % de la densité théorique du matériau, qui est la plus élevée à ce jour rapportée dans la littérature. Nous avons ensuite effectué des caractérisations structurales et microstructurales que nous avons corrélées aux propriétés supraconductrices, en particulier la densité de courant critique, Jc mesurée à 20 K. Les meilleurs résultats sont obtenus avec les échantillons in-situ élaborés au-dessous de 800°C appliquant une pression de 300 MPa. Une densité de courant critique élevée Jc = 675 kA/cm2 a été obtenu en champ nul et remarquablement pour un massif MgB2 non dopé, Jc était supérieur à 10 kA/cm2 à 4 T. Un ajout modéré de Mg dans les échantillons frittés à haute température (>900°C) a permis de réduire les phases appauvries en Mg (MgB4) et d’améliorer la connectivité inter-grains et par conséquent, la densité de courant critique Jc en champs faibles. La substitution du bore par du carbone abaisse légèrement la température critique, Tc mais améliore le piégeage des vortex, d'où des performances optimisées pour Jc à haut champ (autour de 10 kA/cm2 à 5 T et 20 K) avec le mélange contenant du bore enrobé de carbone ou un dopage de nano SiC. De plus, les propriétés fonctionnelles ont été étudiées avec des disques MgB2 de grandes tailles, en particulier les forces de lévitation et de stabilisation ainsi que le champ piégé. Ces résultats de mesures ont démontré la possibilité d’intégrer des cryoaimants supraconducteurs MgB2 dans des dispositifs de sustentation magnétique utilisant un fluide cryogénique tel que l'hydrogène ou le néon.

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'. The following topics are covered by the review: multiscale modelling of hydrides and hydrogen sorption mechanisms; synthesis and processing techniques; catalysts for hydrogen sorption in Mg; Mg-based nanostructures and new compounds; hydrides based on intermetallic TiFe alloys, high entropy alloys, Laves phases, and Pd-containing alloys. Finally, an outlook is presented on current worldwide investments and future research directions for hydrogen-based energy storage

International audience; The addition of methanesulfonic acid to N-(2,6-dimethylpyridin-4-yl)-N-methyl-2-iso-propylaniline led to the selective protonation of the pyridine nitrogen atom, resulting in a significant deceleration of the rotation rates around both N-pyridyl and N-(i-Pr)phenyl bonds through a relayed brake mechanism.

N-Methyl-2-methoxymethylanilines 1 bearing vari- ous 5-substituted-pyrimidin-2-yl groups were prepared, and their rotational behaviors were explored in detail. It was revealed that the rotational barriers around two N−Ar bonds increase in proportion to the electron-withdrawing ability of substituents X at the 5-position., This work was partly supported by JSPS KAKENHI Grant Number C 20K06945. VT-NMR experiments have been performed using the PRISM core facility (Biogenouest, UMS Biosit, Université de Rennes 1- Campus de Villejean- 35043 RENNES Cedex, FRANCE).

National audience; En 2009, il a été découvert que la phase β-FeSe possède une transition supraconductrice à 9 K [1] voir 15 K [2]. Ce matériau possède de nombreux avantages tels que l’absence de terres rares, problématique dans le développement et la production de nombreux supraconducteurs et autres matériaux magnétiques, ou sa relativement faible toxicité en comparaisons des supraconducteurs à base de Fer-Arsénique [3], [4]. Également, c’est un supraconducteur fabricable sous forme de polycristal et peut être dopé par différents éléments tels que l’argent [5], le Tellure [6], le soufre [7] ou les métaux alcalins [8] augmentant fortement ses propriétés supraconductrices, le rendant ainsi potentiellement compétitif pour des applications à 20 K (hydrogène liquide).En parallèle, le développement de la méthode de synthèse par Frittage Flash (SPS) permet une préparation d’échantillons très dense, en peu de temps et avec une grande liberté sur le choix de la taille et de la forme. Ainsi la préparation de supraconducteur polycristallin par SPS s’accorde beaucoup plus avec la production industrielle massive et variée des moteurs électriques.Des échantillons de FeSe polycristallins ont été produit par SPS, par méthode Ex-situ (recuit par SPS) et In-situ (synthèse et recuit par SPS) afin de produire une phase β-FeSe pure et de garantir les meilleures propriétés supraconductrices.Références:[1]F.-C. Hsu et al., « Superconductivity in the PbO-type structure ␣-FeSe », p. 3.[2]M. Ma, D. Yuan, Y. Wu, H. Zhou, X. Dong, et F. Zhou, « Flux-free growth of large superconducting crystal of FeSe by traveling-solvent floating-zone technique », Supercond. Sci. Technol., vol. 27, no 12, p. 122001, déc. 2014, doi: 10.1088/0953-2048/27/12/122001.[3]D. C. Johnston, « The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides », Adv. Phys., vol. 59, no 6, p. 803‑1061, nov. 2010, doi: 10.1080/00018732.2010.513480.[4]G. R. Stewart, « Superconductivity in iron compounds », Rev. Mod. Phys., vol. 83, no 4, p. 1589‑1652, déc. 2011, doi: 10.1103/RevModPhys.83.1589.[5]A. Galluzzi, M. Polichetti, K. Buchkov, E. Nazarova, D. Mancusi, et S. Pace, « Critical current and flux dynamics in Ag-doped FeSe superconductor », Supercond. Sci. Technol., vol. 30, no 2, p. 025013, févr. 2017, doi: 10.1088/1361-6668/30/2/025013.[6]K.-W. Yeh et al., « Tellurium substitution effect on superconductivity of the α-phase iron selenide », EPL Europhys. Lett., vol. 84, no 3, p. 37002, nov. 2008, doi: 10.1209/0295-5075/84/37002.[7]Y. Sun, S. Pyon, et T. Tamegai, « Effect of S doping on the critical current density and vortex dynamics in FeSe single crystal », Phys. C Supercond. Its Appl., vol. 530, p. 55‑57, nov. 2016, doi: 10.1016/j.physc.2016.05.023.[8]T. P. Ying et al., « Observation of superconductivity at 30∼46K in A x Fe 2 Se 2 (A = Li, Na, Ba, Sr, Ca, Yb and Eu) », Sci. Rep., vol. 2, no 1, Art. no 1, mai 2012, doi: 10.1038/srep00426.

International audience; The magnetic flux dissipation from the MgB 2 bulk magnets during pulsed field magnetization (PFM) processes has been estimated for the samples fabricated by hot-pressing (HP) and spark plasma sintering (SPS). We defined the parameters as field penetration ratio B P /B a and the field trapping ratio B T /B P to evaluate the flux motion and performance. The data plots of trapping ratio B T /B P showed us two regions which originate from the fast flux flow and flux jump. The field trapping performance was drastically degraded when the flux jump happened. Flux jump happened at various times after the peak field. A very late flux jump happened at 420 ms which severely degraded the trapped field. This time delay, much larger than the heat propagation time in the MgB 2 sample, remains to be explained.

International audience; EBSD analysis can provide information about grain orientation, texture and grain boundary misorientation of bulk superconducting MgB2 samples intended for supermagnet applications. However, as the grain size of the MgB2 bulks is preferably in the 100–200 nm range, the common EBSD technique operating in reflection mode works only properly on highly dense samples. In order to achieve reasonably good Kikuchi pattern quality on all types of MgB2 samples, we apply here the newly developed transmission EBSD (t-EBSD) technique to spark-plasma sintered MgB2 samples. This method requires the preparation of TEM slices by means of focused ion-beam milling, which are then analysed within the SEM, operating with a custom-built sample holder. To obtain multiphase scans, we identified the Kikuchi pattern of the MgB4 phase which appears at higher reaction temperatures and may act as additional flux pinning sites. We present here for the first time EBSD mappings of multiple phases, which include MgB2, MgB4 and MgO. Lay Description The electron backscatt er diffraction (EBSD) technique operating in the scanning electron microscope provides information on the crystallographic orientation the material by recording Kikuchi patterns. In polycrystalline samples, it becomes possible to analyse the orientations of the grains to each other. The metallic superconductor with the currently highest superconducting transition temperature, MgB2 with a Tc of 38.5 K, can be used in applications in polycrystalline form. One such application of interest are trapped field magnets or supermagnets, where the superconductor cooled in an applied magnetic field can trap the magnetic field as vortices at numerous flux pinning sites in the sample. When the external magnetic field is removed, the sample will stay magnetised as long as it is kept cool, and importantly, the trapped magnetic fields can be much higher as for any permanent magnet. However, the small size of the MgB2 grains in the 100–200 nanometre range requires a different approach when using the EBSD technique on such samples. The recently developed EBSD technique working in transmission mode (t-EBSD) helps considerably to image such materials. In this approach, a tiny TEM slice has to be milled out from the original sample by using focused ion beam milling. To understand the properties of the flux pinning in the spark-plasma sintered MgB2 sample, we had to identify the Kikuchi pattern of MgB4, which is another, non-superconducting phase appearing at higher reaction temperatures required to compact the material. Using this information, we could perform EBSD scans using three different phases, MgB2, MgB4 and MgO. The EBSD mappings enable to see where the secondary phase particles are located in the sample, and to judge if the particles could work as flux pinning sites. © 2019 The Authors Journal of Microscopy © 2019 Royal Microscopical Society

International audience; The Pulsed Field Magnetization (PFM) is a compact and fast method to magnetize superconducting bulks compared to the field cooling method. However, the heat generation induced by the strong applied variable magnetic field during the PFM makes high trapped magnetic field harder to achieve. In order to make the REBaCuO bulks easier to magnetize by PFM, superconducting bulks including a superconducting weld are studied taking into account the thermal and electromagnetic properties of the weld different from those of the bulk body. This artificial grain boundary obtained by superconducting welding method might increase the trapped magnetic flux without increasing the applied magnetic field. In this paper, we are modelling the superconducting weld behavior during PFM using a 3D finite element model with the software COMSOL Multiphysics. The simulations are based on an H-formulation from Maxwell's equations and the heat diffusion equation. We analyse the impact of the critical current Jc of the weld on the trapped magnetic field.

High-Temperature Superconductors (HTS) considerably accelerate the development of superconducting machines for electrical engineering applications such as fully electrical aircraft. This present contribution is an overview of different superconducting materials that can be used as magnetic screens for the inductor of high specific power electrical machines. The impact of the material properties, such as the critical temperature (Tc) and the critical current density (Jc), on the machine performances is evaluated. In addition, the relevance to flux modulation machines of different HTS bulk synthesis methods are addressed.

International audience; Mg-B superconducting bulk materials are characterized as simple and uniform metallic compounds, and capable of trapping homogeneous field with beautiful conical shapes. Although pulsed-field magnetization technique (PFM) is expected as a cheap and an easy way to activate them, the heat generation due to magnetic flux motion in bulk magnets causes serious degradation of captured fields. It is important to suppress the flux motions during PFM to decrease the heat generation. In this study, authors precisely estimated the flux trapping to the bulk samples, found that the flux-shielding effect related to the sample dimensions. Moreover, the Ti-addition to the bulk sample affected the frequency of flux jump happenings. The magnetic field capturing of 5.0wt%Ti-added samples reached the highest value of 0.76 T, while the starting point of magnetic field invasion into the sample centre shifted from 1.0 T to 1.2 T with increasing sample thickness from 3.67 mm to 5.80 mm. The occurrence of flux jumps was suppressed in 5.0wt%Ti-dopped sample, which means that the heat capacity of the compounds shifted with varying Ti addition, effectively prevented the flux jumps.

Made available in DSpace on 2021-06-25T10:17:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Deutsche Forschungsgemeinschaft The microstructure and magnetic characterizations of non-woven, fabric-like YBa2Cu3Oy (YBCO) nanofiber mats are reported. The samples were produced by solution blow spinning (SBS), starting from a sol-gel solution of the precursor materials in polyvinylpyrrolidone. In the present work, the nanowire network samples were morphologically characterized by scanning electron microscopy, and the superconducting properties were measured by magnetometry. An interesting feature is the appearance of a paramagnetic Meissner effect (PME) when field-cooling, firstly verified in that sort of sample. The PME appears only in very small applied magnetic fields, which is similar to previous observations of the PME on an artificially granular YBCO thin film, but distinctly different from bulk samples investigated in the literature. Thus, we explain the PME by flux trapping within the voids of the nanoporous structure of the nanofiber mats. [Figure not available: see fulltext.]. Superconductivity and Advanced Materials Group School of Engineering São Paulo State University (UNESP) Campus at Ilha Solteira Experimental Physics Saarland University Shibaura Institute of Technology Superconductivity and Advanced Materials Group School of Engineering São Paulo State University (UNESP) Campus at Ilha Solteira Deutsche Forschungsgemeinschaft: DFG-ANR Ko2323-10

On Krylov subspace methods such as the Conjugate Gradient (CG), the number of iterations until convergence may increase due to the loss of computation accuracy caused by rounding errors in floating-point computations. Besides, as the order of operations is non-deterministic on parallel computations, the result and the behavior of the convergence may be non-identical in different environments, even for the same input. This paper presents a new approach for the CG method with high accuracy as well as bit-level reproducibility of computed solutions on many-core processors, including both x86 CPUs and NVIDIA GPUs. In our proposed approach, accurate and reproducible operations are installed into all the inner-product based operations such as matrix-vector multiplication and dot-product, which are the main sources that may disturb reproducibility in the CG method. The accurate and reproducible operations are performed using the Ozaki scheme, which is the error-free transformation for dot-product that can ensure the correct-rounding. As this method can be built upon vendor-provided linear algebra libraries such as Intel Math Kernel Library and NVIDIA cuBLAS/ cuSparse, it reduces the development cost. In this paper, showing some examples with the non-identical conver-gences and computed solutions on different platforms, we demonstrate the applicability and the effectiveness of the proposed approach as well as its performance on both CPUs and GPUs. Besides, we compare against an existing accurate and reproducible CG implementation based on the Exact BLAS (ExBLAS) on CPUs.

International audience; For possible applications as trapped field (TF) magnets, it is essential to fabricate large, polycrystalline bulk samples from the FeSe compound, the simplest high-Tc superconductor (HTSc) possible. FeSe is relatively cheap to prepare, and does not contain any rare-earth material. The grain boundaries in this compound are not acting as weak links as it is the case for the YBCO compound. Although the transition temperature, Tc, is just below 10 K, the upper critical fields are comparable with other HTSc. Preparing the FeSe samples using solid-state sintering yields samples exhibiting strong magnetic hysteresis loops (MHLs), and the superconducting contribution is only visible after subtracting MHLs from above Tc. Due to the complicated phase diagram [1], the samples are a mixture of several phases, α-FeSe, β-FeSe, δ-FeSe (Fe7Se8) and metallic α-Fe [2]. The amount of the latter two phases depends directly on the Se loss during the sintering process. The δ-FeSe is antiferromagnetic, and α-Fe is ferromagnetic [3]. In the present contribution, we show MHLs of a variety of samples measured up to ±7 T and determine the magnetic characteristics, together with the amount of superconductivity determined from M(T) measurements. We performed a thorough analysis of the microstructures using polarization microscopy, Kerr effect, MFM, SEM, EBSD and TEM in order to establish a relation between microstructure and sample properties. To prepare good superconducting samples, the presence of the (anti)ferromagnetic phases must be reduced by carefully adjusting the Se content using Ti foils as getter materials. Measuring magnetoresistance of these samples [4] implies that the samples are always cooled in the own local field, and thus, the analysis of the resistance data calculating the fluctuation-induced conductivity above Tc [5] is strongly affected by this local magnetic field. We demonstrate the importance of preparing phase-pure FeSe samples, which are essential for the various applications envisaged. This work is part of the SUPERFOAM international project funded by ANR and DFG under the references ANR-17-CE05-0030 and DFG-ANR Ko2323-10, respectively. References [1] H. Okamoto, J. Phase Equilibria 12, 383 (1991). [2] P. Diko et al., Physica C 476, 29 (2012). [3] A. J. Williams, T. M. McQueen, R. J. Cava, Solid State Commun.149, 1507 (2009). [4] T- Karwoth et al., J. Phys. Conf. Ser. 1054, 012018 (2018). [5] A. Almessiere et al., Mat. Chem. Phys. 243, 122665 (2020).

International audience; The development of the sintering process for the synthetization of superconducting Iron-selenide (FeSe) polycrystal enables a quick and cheap fabrication of superconducting bulks for trapped field applications without the use of Rare Earths or toxic elements. A relevant number of papers were published in the literature in order to determine the best way to produce a pure β-phase, responsible of the superconductivity without any other non-desirable phases (α-FeSe, unreacted Fe, FeSe – also called δ-FeSe). Using the collected information, we produced a pure β-phase by classic sintering process at temperatures above 685°Cfollowed by annealing below 450°C for optimizing the sample and improvement of the critical currents. Using the Spark Plasma Sintering method enables an improved homogeneity and a better grain coupling, which leads to a higher quality for FeSe superconducting bulks and an increased sample density. The consequence is another increase of the critical currents which makes the samples competitive for trapped bulks applications.

Bianchi, E. et al., The study of hot corinos in solar-like protostars has been so far mostly limited to the Class 0 phase, hampering our understanding of their origin and evolution. In addition, recent evidence suggests that planet formation starts already during Class I phase, which therefore represents a crucial step in the future planetary system chemical composition. Hence, the study of hot corinos in Class I protostars has become of paramount importance. Here, we report the discovery of a hot corino towards the prototypical Class I protostar L1551 IRS5, obtained within the ALMA (Atacama Large Millimeter/submillimeter Array) Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars).We detected several lines from methanol and its isotopologues (13CH3OH and CH2DOH), methyl formate, and ethanol. Lines are bright towards the north component of the IRS5 binary system, and a possible second hot corino may be associated with the south component. The methanol lines' non-LTE analysis constrains the gas temperature (100 K), density (1.5 × 108 cm3), and emitting size (10 au in radius). All CH3OH and 13CH3OH lines are optically thick, preventing a reliable measure of the deuteration. The methyl formate and ethanol relative abundances are compatible with those measured in Class 0 hot corinos. Thus, based on this work, little chemical evolution from Class 0 to I hot corinos occurs., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Bulk discs (20 mm diameter and 4.3 mm thickness) of MgB2 added with Ge2C6H10O7 were obtained by Spark Plasma Sintering. Six samples with composition MgB2(Ge2C6H10O7)0.0014 and one undoped sample were fabricated under similar conditions and were magnetically characterized in order to determine the scattering of properties and reproducibility. The main source of the scattering of the properties is the decomposition of the additive due to elimination of the organic part in gas form, which occurs stepwise with intensive vacuum drops at around ~ 560 and ~ 740 °C. A third drop, which is sometimes not well resolved being part of the second peak at 740 °C, occurs at ~ 820 °C. The critical temperature at the midpoint of the transition, Tc, shows only a relatively small variation between 37.4 and 38 K, and the irreversibility field at a low temperature of 5 K takes values between 8 and 10 T. The pinning force and pinning force related parameters do not correlate with the carbon substituting for boron in MgB2 and suggest a synergetic influence of the microstructural details and carbon. Overall, despite the superconducting properties scattering, the samples are of high quality. Stacked into a column of six samples, they can trap at the center and on the surface of the column a magnetic field of 6.78 and 5.19 T at 12 K, 5.20 and 3.98 T at 20 K and 2.39, and 1.96 T at 30 K. These promising values, combined with facile fabrication of the samples with relatively high quality and reproducibility, show the feasibility of their use in building complex and large compound arrangements for bulk magnets and other applications.

MgB2 bulk superconductors are expected to be utilized as rare-earth-free and lightweight trapped field magnets. However, the flux jumps frequently happen during the magnetizing processes, and heavily degrade the field-trapping performances. We have investigated the effect of additives to the MgB2 bulk samples prepared by spark plasma sintering process, and observed various flux jumps during the pulsed field magnetizing processes, which were carried out at 14 K which was obtained by the 2-stage GM cryocooler. The authors classified the flux motions as three categories as “no flux flow”, “fast flux flow”, and “flux jump” regions, and investigated the conditions where the flux jumps happen. We observed some drastic flux jumps in the pristine and clarified the effect of graphene addition to the flux jumps. The experimental results showed us a possible expansion of no flux jump region, and suggested us the improvement of field trapping capability.

International audience; N-Aryl-N-methyl-2-tert-butyl-6-methylaniline derivatives exhibit a rotationally stable N-C axially chiral structure and the rotational barriers around an N-C chiral axis increased with the increase in electron-withdrawing character of para-substituent on the aryl group. X-ray crystal structural analysis and the DFT calculation suggested that the considerable change of the rotational barriers by the electron effect of para-substituents is due to the disappearance of resonance stabilization energy caused by the twisting of para-substituted phenyl group in the transition state. This structural property of the N-C axially chiral anilines was employed to reveal a new acid-decelerated molecular rotor caused by the protonation at the remote position (remote proton brake).

International audience; When the MgB2 bulk body is magnetized by the pulse magnetizing method, the MgB2 bulk can take the role of a pseudo permanent magnet. However, it was confirmed that the temperature at which MgB2 is expected to be used is close to the critical temperature (TC) of MgB2 and the specific heat is small, so that the heat generated by the pulse magnetizing method causes flux jump and the trapped magnetic field performance deteriorates. In this study, pulse magnetizing was performed on different samples to verify and consider changes in the trapped magnetic field performance. As the sample, the sample obtained by changing the amount of titanium added was synthesized by uniaxial hot pressing and the sample synthesized by spark plasma sintering (SPS). Figure (a) shows a comparison of the trapped magnetic fields of the samples synthesized by the uniaxial hot press. From Fig. (A), it was shown that the capture magnetic field performance may be improved or deteriorated by the composition ratio of the material, the addition of impurities, and the method of synthesizing the bulk material.

International audience; With the objective to concurrence the well-known melt texturing YBCO samples in term of irreversible field and critical current, infiltration growth YBCO bulks (IG-processed) show a recent increase of interest due to their advantage of better controlling the shape of the final product and better mechanical stability. Two types of IG-processed YBCO samples were developed: standard bulk samples and superconducting foams which show the advantage of a huge cooling capacity and a low weight due to his low density, particularly appreciated for space applications. Intended for use as permanent superconducting magnets (trapped field (TF) magnets), precedents works were done to evaluate the pinning properties of such materials by pinning force scaling (Dew-Hughes and Kramer) but only under relatively low magnetic field (up to 9 T). Considering a very high irreversible field (Hirr), even at 77 K, a lot of assumptions and extrapolations were needed. Small pieces of both designs (standard bulk and foam) were cut and mechanically polished (1 x 1 x 0.1 mm3) according to the crystallographic orientation (H // c). To experimentally determine the pinning properties for magnetic field above 9 T, we were able to make measurements at high magnetic field (above 30 T) for different temperatures between 85 K and 40 K with the help of EMFL facilities using Cantilever Torque Magnetometry at the High Magnetic Field Laboratory of Nijmegen.

Poster; International audience; Pieces of bulk, superconducting FeSe samples prepared by solid-state sintering were irradiated with 2.5 MeV electrons (T = 23.5 K) at SIRIUS facility using two different fluences, 2×10^19 electrons/cm2 and 4×10^19 electrons/cm2. In contrast to previous work performed on FeSe single crystals, the bulk FeSe samples are polycrystalline without specific texture and exhibit a density of ~4 g/cm3 (= 78% of theoret. density) due to pores. Furthermore, the samples contain magnetic impurities which lead to a ferromagnetic signal of the sample. Such bulk FeSe samples are intended as base material for superconducting trapped field magnets operating at 5 K, with the benefit of a higher upper critical field, Hc2, and reduced flux jump probability as compared to MgB2. The electron irradiation introduced point defects to the FeSe grains. As result, the superconducting transition temperature, Tc, is slightly reduced, depending on the fluence, but the critical currents are increased by about 20-30%. We discuss the changes of Tc, of the magnetic background and the superconducting properties of the samples before and after the electron irradiation.

Poster; International audience; We suggest the use of superconducting trapped field magnets (TF) for Flux-Pinning Docking Interfaces (FPDI) in satellite systems. Previous work introducing the FPDI concept to cube-sat satellites was using bulk high-Tc superconductors and permanent magnets of Nd-Fe-B. This arrangement was proven to work both experimentally and theoretically. However, such FPDIs have limited magnetic field strength, consist of heavy-weight material, and can only be used with a single purpose. Replacing the magnetic material in the FPDI by a TF-magnet would enable the interface to operate for both purposes, i.e., generating a (stronger) magnetic field and trapping it. We show the requirements for such a system and discuss the possible gains when using a TF-FPDI in satellites. A further possibility to reduce the system weight would be the use of superconducting foams as superconducting material.

Invited Poster; International audience; Bulk MgB2 superconductors have a promising potential as trapped field magnets, and have a number of attractive properties, such as being rare-earth-free and a low density. However, these superconducting materials have magneto-thermal instabilities visible through flux jumps. These flux jumps occur during conventional magnetization measurements, even at low sweep rates below 10 T/min. In this paper, we investigated the influence of different additions on the flux jumps during Pulsed Field Magnetization (PFM) of MgB2 bulk samples obtained by spark plasma sintering (SPS). PFM experiments are carried out on MgB2 pellets (20 mm diameter and 3.5 mm height) cooled down to an initial temperature of 10 K, 15 K and 20 K. Finally, we discuss the potential of the additions to the MgB2 material in order to avoid flux jumps and increase the resulting trapped field capabilities.

We would like to thank A. Wiederhold, X. L. Zeng (Saarland University, Germany), C. Chang, T. Hauet (IJL Nancy, France) for assistance during the measurements.; International audience; We compare the temperature and field dependence of the critical current densities of high-Tc superconductor materials intended for various bulk applications like trapped-field magnets. This comprises bulk samples of YBa2Cu3Ox (YBCO), MgB2 and iron-based materials, including also various versions of the YBCO compound like melt-textured ones, infiltration-growth processed ones, and YBCO foams. Critical current densities and flux pinning forces were obtained from magnetization loops measured using Quantum Design SQUID and PPMS systems with applied magnetic fields of up to ±9 T. The obtained data are compared to each other with respect of the optimal cooling temperature possible using modern cryocoolers. Furthermore, we plot the temperature dependencies of the critical current densities versus the normalized temperature t = T /Tc. This enables a direct judgement of the performance of the material in the trapped field applications.

International audience; Bulk High Temperature Superconductors (HTS) can be magnetized and act as permanent magnet much stronger than conventional ones as NdFeB. The design of the inductor is a key point to perform the desired magnetization of the HTS bulk. In this paper, we focus on modeling a Pulsed Field Magnetization (PFM) process of an HTS bulk using a coil powered with a magnetizer. The built model is a 2D axisymmetric problem, based on the H formulation and coupled with electrical equations though the magnetic flux seen by the magnetizing coil. The calculation of this magnetic flux in the H formulation is not trivial and was validated using magnetic vector potential formulation on a coil in the air. Assuming different operating conditions, the bulk HTS is then modeled using four different properties corresponding to air, perfect diamagnetic, copper and HTS. It was shown that simulating a PFM process could lead to different value of peak current and applied magnetic field to the bulk HTS, depending on the critical current density of the bulk, for example. These variations are in the range of the air and diamagnetic cases. Therefore, the proposed method should be used in order to predict a realistic trapped magnetic field in the HTS bulk by taking into account its reaction seen by the coil during the PFM process.

International audience; The iron-based superconductors display interesting superconducting properties for applications, such as their reasonably high superconducting transition temperature Tc, very high upper critical fields Hc2, and relatively small anisotropy [1]. Among them, FeSe superconductor shows exceptional characteristics: Tc above 100 K with monolayer FeSe [2] or 27 K under pressure [3], modification of the properties by adding Te, a very rich phase diagram. It also allows an easy and cheap production of superconducting material and they are rare-earth free. Furthermore, superconducting properties are closely related with the presence of defect and one way to enhance or decrease those properties is to use irradiation process. Few experimentations where already done on single crystal FeSe [4]-[9], but not on polycrystalline FeSe, which is most relevant for applications like, e.g., supermagnets. This project is being carried out in this context. By means of two experimental campaigns, our objective is to add point-like defects (electron irradiation with SIRIUS facility) and columnar tracks (heavy-ion irradiation with GANIL facility). Magnetization loops and critical current densities of FeSe samples after electron irradiation will be compared to the reference one. Some analysis will be done regarding a possible phase transition of the characterized samples.References:[1]A. Gurevich, “Iron-based superconductors at high magnetic fields,” Rep. Prog. Phys., vol. 74, no. 12, p. 124501, Dec. 2011.[2]J.-F. Ge et al., “Superconductivity above 100 K in single-layer FeSe films on doped SrTiO 3,” Nat. Mater., vol. 14, no. 3, pp. 285–289, Mar. 2015.[3]Y. Mizuguchi, F. Tomioka, S. Tsuda, T. Yamaguchi, and Y. Takano, “Superconductivity at 27K in tetrago-nal FeSe under high pressure,” Appl. Phys. Lett., vol. 93, no. 15, p. 152505, Oct. 2008.[4]F. Massee et al., “Imaging atomic-scale effects of high-energy ion irradiation on superconductivity and vortex pinning in Fe(Se,Te),” Sci. Adv., vol. 1, no. 4, p. e1500033, May 2015.[5]Y. Sun, A. Park, S. Pyon, T. Tamegai, T. Kambara, and A. Ichinose, “Effects of heavy-ion irradiation on FeSe,” Phys. Rev. B, vol. 95, no. 10, Mar. 2017.[6]A. E. Kar’kin, T. Wolf, A. N. Vasil’ev, O. S. Volkova, and B. N. Goshchitskii, “Effect of neutron irradiation on the properties of the FeSe compound in the superconducting and normal states,” Phys. Met. Metallogr., vol. 113, no. 5, pp. 455–459, May 2012.[7]Y. Sun et al., “Enhancement of critical current density and mechanism of vortex pinning in H + -irradiated FeSe single crystal,” Appl. Phys. Express, vol. 8, no. 11, p. 113102, Nov. 2015.[8]S. Teknowijoyo et al., “Enhancement of superconducting transition temperature by pointlike disorder and anisotropic energy gap in FeSe single crystals,” Phys. Rev. B, vol. 94, no. 6, Aug. 2016.[9]D. Ahmad et al., “Effect of proton irradiation on the fluctuation-induced magnetoconductivity of FeSe 1− x Te x thin films,” New J. Phys., vol. 19, no. 9, p. 093004, Sep. 2017.

At Present, the environmental protection penetrates public awareness to decrease atmospheric emissions as important efforts for increasing living quality in air from various gaseous effects. Technically, it has forced industrial sectors to control pollutant productions while operating machineries of engineering processes to keep all contaminant materials. This condition has also forced the power system operation to modify operational strategies of thermal power plants considered pollutant productions from combustions of fossil fuels for reducing emissions. This paper demonstrates new approaches for measuring pollutant penetrations embedded in the single priority function considered an emission standard, a dynamic penalty factor, and Thunderstorm Algorithm (TA). By considering the IEEE 62-bus system model, results obtained show that the hourly computation has different performances for the 24 hours operation. It also indicates that pollutant discharges are dominated gradually by higher contributors associated with scheduled power plants. The convergence speed of TA is smooth and fast for determining the optimal solution, which are ranged in 6-20 for the cycle and 1.8-3.8 s for the time consumption. Moreover, the 24 hours operation is powered totally in 60,826.10 MW for feeding the total load of 56,820.50 MW. This operation also spends in 291,870.60 $ for the fuel procurement and 83,233.70 $ for the compensation of the pollutant production during existing 19 generating units. In total, the accumulation of pollutant discharges from 19 power plants is 68,012.20 kg.

International audience; The FeSe compound is the simplest high-temperature superconductor (HTSc) possible, and relatively cheap, not containing any rare-earth material. Although the transition temperature, Tc, is just below 10 K, the upper critical fields are comparable with other HTSc. Preparing FeSe using solid-state sintering yields samples exhibiting strong ferromagnetic hysteresis loops (MHLs), and the superconducting contribution is only visible after subtracting MHLs from above Tc. Due to the complicated phase diagram, the samples are a mixture of several phases, the superconducting beta-FeSe, and the non-superconducting delta-FeSe and gamma-FeSe. Furthermore, antiferromagnetic Fe7Se8 and ferromagnetic alpha-Fe may be contained, depending directly on the Se loss during the sintering process. Here, we show MHLs measured up to ±7 T and determine the magnetic characteristics, together with the amount of superconductivity determined from M(T ) measurements. We also performed a thorough analysis of the microstructures in order to establish a relation between microstructure and the resulting sample properties.

International audience; The fluorine atom is the second smallest atom; nevertheless, the ortho-fluoro group may lead to stable N-aryl atropisomers when the steric demand of the flanking substituents is large enough. 2-Alkyl-3-(2-fluorophenyl)quinazolin-4-ones and 3-(2-fluorophenyl)-4-methylthiazoline-2-thione were found to be the first N-aryl axially chiral compounds bearing an ortho-fluoro group whose enantiomers were isolated at ambient temperature. The reaction of alkyl halides with the anionic species prepared from 2-ethyl-3-(2-fluorophenyl)quinazolin-4-one presenting an N−C axial chirality provided a model reaction for quantitative evaluation of the steric discrimination (slight difference of steric factor) between hydrogen and fluorine atoms. In the case of low steric demand (allylation reaction) no diastereoselectivity was detected, while in the case of high steric demand (isopropylation reaction) the diastereoselectivity became significant.