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961.
Stefan Baessler Mathieu Beau Michael Kreuz Vladimir N. Kurlov Valery V. Nesvizhevsky Guillaume Pignol Konstantin V. Protasov Francis Vezzu Aleksey Yu. Voronin 《Comptes Rendus Physique》2011,12(8):707-728
The existence of quantum states of matter in a gravitational field was demonstrated recently in the Institut Laue–Langevin (ILL), Grenoble, in a series of experiments with ultra cold neutrons (UCN). UCN in low quantum states is an excellent probe for fundamental physics, in particular for constraining extra short-range forces; as well as a tool in quantum optics and surface physics. The GRANIT is a follow-up project based on a second-generation spectrometer with ultra-high energy resolution, permanently installed in ILL. It has been constructed in framework of an ANR grant; and will become operational in 2011. 相似文献
962.
We construct an explicit filtration of the ring of algebraic power series by constructible sets, measuring the complexity of these series. As an example of use of this, we give a bound on the dimension of the set of algebraic power series of bounded complexity lying on an algebraic variety defined over the field of power series. 相似文献
963.
Guillaume Lahiner James Zappata Jeremy Cure Nicolas Richard Mehdi Djafari-Rouhani Alain Estève 《Combustion Theory and Modelling》2019,23(4):700-715
Sputter-deposited Al/CuO multilayers capable of highly energetic reactions have been the subject of intense studies for tunable initiation and actuation. Designing high performance Al/CuO-based initiator devices definitively requires reliable prediction of their ignition and reaction kinetics including self-heating or ageing as a function of heating rate and environmental conditions. The paper proposes a heterogeneous reaction model integrating an ensemble of basic mechanisms (oxygen diffusion, structural transformations, polymorphic phase changes) that have been collected from recent experimental investigations. The reaction model assumes that the rate of reaction is limited by the transport of oxygen across the growing layer of Al2O3 separating Al and CuO. Importantly, we show that the model predicts reasonably all exotherms through a wide range of temperature (ambient – 1000°C), all resulting from a pure diffusion process as experimentally observed for such Al/CuO multilayers. The model shows how the temperature ramp affects the structure of the multilayer and especially the growth of alumina-based interfacial regions. It highlights the importance of the interfacial chemistry evolution such as the native mixture of AlxCuyOz transformation into a thin amorphous alumina, and the polymorphic phase transformation of this latter. The first one occurring at ~350°C results in a loss of continuity of the interface leading to the accelerated redox reaction whereas the second one occurring between 500 and 600°C produces a denser barrier to oxygen diffusion leading to the stop of redox reaction. We finally use the model to simulate thermal annealing as usually performed in accelerated ageing experiments. We theoretically observe and experimentally validate that a two weeks exposure of the multilayers at 200°C starts degrading the multilayers thermal properties whereas when the temperature remains below 200°C, the material keeps its entire integrity. 相似文献
964.
Dr. Djamila Guettas Dr. Frédéric Gendron Dr. Guglielmo Fernandez Garcia Dr. François Riobé Dr. Thierry Roisnel Dr. Olivier Maury Dr. Guillaume Pilet Prof. Olivier Cador Dr. Boris Le Guennic 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(19):4389-4395
A textbook dysprosium dinuclear complex based on acetylacetone ligands, [Dy2(acac)4(μ2-acac)2(H2O)2], has been synthesized and fully characterized. This simple dimeric lanthanide complex shows well-resolved solid-state luminescence and behaves as a single-molecule magnet under zero DC field. A seminal crystal-field approach is used to marry both magnetism and luminescence in the frame of an energetic picture. 相似文献
965.
Dr. Nathalie Daro Tony Vaudel Luc Afindouli Dr. Samuel Marre Dr. Cyril Aymonier Dr. Guillaume Chastanet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16286-16290
Switchable materials are increasingly considered for implementation in devices or multifunctional composites leading to a strong need in terms of reliable synthetic productions of well-defined objects. Here, an innovative and robust template-free continuous process was developed to synthesize nanoparticles of a switchable coordination polymer, including the use of supercritical CO2, aiming at both quenching the particle growth and drying the powder. This all-in-one process offers a 12-fold size reduction in a few minutes while maintaining the switching properties of the selected spin crossover coordination polymer. 相似文献
966.
Dr. Cheng-Xia Chen Yan-Zhong Fan Chen-Chen Cao Dr. Hai-Ping Wang Ya-Nan Fan Dr. Ji-Jun Jiang Dr. Zhang-Wen Wei Prof. Guillaume Maurin Prof. Cheng-Yong Su 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(37):8254-8261
Known for excellent stability, porosity and functionality, the high-valent Zr4+ metal–organic frameworks (Zr-MOFs) still meets synthetic challenge in modulating the strength of Zr-Ocarboxylate linkage. Herein we explore the unusual coordination dynamics of fluorinated Zr-MOFs by designing two trifluoromethyl modified ligands with distinct geometry preference to form a family of thermodynamic and kinetic products. The low-connecting kinetic Zr-MOFs possess substitutable coordination sites to endow Zr6-cluster with extra dynamic behaviors, thus opening a post-synthetic pathway to sequential reassembly/disassembly processes. Comprehensive factors, including ligand geometry, Zr6-cluster connectivity, acid modulator and reaction temperature/concentration, have been studied for controllable syntheses. The stability, hydrophobicity and gas adsorption/separation properties of obtained Zr-MOFs are explored. This work sheds light on the understanding of the dynamic coordination chemistry of Zr-MOFs beyond strong Zr−O bond, which poses a versatile platform for modification and functionalization of Zr-MOFs. 相似文献
967.
968.
969.
Guillaume Blanger‐Chabot Holger Braunschweig 《Angewandte Chemie (International ed. in English)》2019,58(40):14270-14274
The electron‐precise binary boron subhalide species [B2X6]2? X=F, Br, I) were synthesized and their structures confirmed by X‐ray crystallography. The existence of the previously claimed [B2Cl6]2?, which had been questioned, was also confirmed by X‐ray crystallography. The dianions are isoelectronic to hexahaloethanes, are subhalide analogues of the well‐known tetrahaloborate anions (BX4?), and are rare examples of molecular electron‐precise binary boron species beyond B2X4, BX3, and [BX4]?. 相似文献
970.
Ludovic D. Marciasini Jimmy Richard Bastien Cacciuttolo Guillaume Sartori Melodie Birepinte Laurent Chabaud Sandra Pinet Mathieu Pucheault 《Tetrahedron》2019,75(2):164-171
Owing to the unusual reactivity of dialkylamine-borane complexes, a methodology was developed to simply access boronic acids. The intrinsic instability of magnesium aminoborohydride was tweaked into a tandem dehydrogenation borylation sequence. Proceeding via an autocatalytic cycle, amineborane dehydrogenation was induced by a variety of Grignard reagents. Overall, addition of the organomagnesium species onto specially designed dialkylamine-borane complexes led to a variety of boronic acids in high yields. In addition, the reaction can be performed under Barbier conditions, on a large scale. 相似文献