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Saskia Menzel Konstantinos D. Demadis Christoph Janiak 《Phosphorus, sulfur, and silicon and the related elements》2020,195(10):830-835
AbstractThe fully deprotonated anion of 1,3,5-benzene-triphosphonic acid 1,3,5-C6H3[PO32?]3 gives rise to deceptively simple 1H and 31P NMR spectra due to a corresponding [AX]3 spin system. The 13C{1H} NMR spectrum reveals two 13C isotopomers which are identified via AXX′2 systems. Results from analysis and iteration are described. 相似文献
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We highlight what seems to be a remaining subtlety in the argument for the cancellation of the total anomaly associated with the M5-brane in M-theory. Then, we prove that this subtlety is resolved under the hypothesis that the C-field flux is charge-quantized in the generalized cohomology theory called J-twisted cohomotopy.
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Braun C Börger SL Boyko TD Miehe G Ehrenberg H Höhn P Moewes A Schnick W 《Journal of the American Chemical Society》2011,133(12):4307-4315
High-pressure synthesis allows both fundamental and materials science research to gain unprecedented insight into the inner nature of materials properties at extreme environment conditions. Here, we report on the high-pressure synthesis and characterization of γ-Ca(3)N(2) and the high-pressure behavior of Mg(3)N(2). Investigation of M(3)N(2) (M = Ca, Mg) at high-pressure has been quite challenging due to the high reactivity of these compounds. Ex situ experiments have been performed using a multianvil press at pressures from 8 to 18 GPa (1000-1200 °C). Additional in situ experiments from 0 to 6 GPa (at RT) at the multianvil press MAX 80 (HASYLAB, Beamline F.2.1, Hamburg) have been carried out. The new cubic high-pressure phase γ-Ca(3)N(2) with anti-Th(3)P(4) defect structure exhibits a significant increase in coordination numbers compared to α-Ca(3)N(2). Contrary, Mg(3)N(2) shows decomposition starting at surprisingly low pressures, thereby acting as a precursor for Mg nanoparticle formation with bcc structure. Soft X-ray spectroscopy in conjunction with first principles DFT calculations have been used to explore the electronic structure and show that γ-Ca(3)N(2) is a semiconductor with inherent nitrogen vacancies. 相似文献
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A straightforward, highly stereoselective protocol toward the synthesis of deuterium-labeled (2R,3S,4S)-β-cyclohexenylserine has been developed. Key steps are a Nozaki-Hiyama-Kishi reaction generating the stereogenic centers and a ring-closing metathesis for the construction of the cyclohexenyl ring system. The labeled amino acid was further activated as an SNAc-ester for feeding experiments. 相似文献
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Bertram Blount E. G. Acheson Kryptol-Gesellschaft Frank W. Mason A. Buss Bermbach v. Victinghoff-Scheel und Völker 《Fresenius' Journal of Analytical Chemistry》1905,44(5):314-315
Ohne Zusammenfassung 相似文献
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Dyer HE Huijser S Schwarz AD Wang C Duchateau R Mountford P 《Dalton transactions (Cambridge, England : 2003)》2008,(1):32-35
The reaction of Sm{N(SiMe3)2}3 with the bis(phenol)amines H2O2N(R) (H2O2N(R) = RCH2CH2N(2-HO-3,5-C6H2(t)Bu2)2; R = OMe, NMe2 or Me) gave exclusively zwitterions Sm(O2N(R))(HO2N(R)). For R = OMe or NMe2 these were efficient catalysts for the ring-opening polymerisation of epsilon-caprolactone and D,L-lactide with a tendency to form cyclic esters; in contrast, no polymerisation was observed for R = Me. 相似文献
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Advances in wide bandgap SiC for optoelectronics 总被引:1,自引:0,他引:1
Haiyan Ou Yiyu Ou Aikaterini Argyraki Saskia Schimmel Michl Kaiser Peter Wellmann Margareta K. Linnarsson Valdas Jokubavicius Jianwu Sun Rickard Liljedahl Mikael Syväjärvi 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(3):1-16
Silicon carbide (SiC) has played a key role in power electronics thanks to its unique physical properties like wide bandgap, high breakdown field, etc. During the past decade, SiC is also becoming more and more active in optoelectronics thanks to the progress in materials growth and nanofabrication. This paper will review the advances in fluorescent SiC for white light-emitting diodes, covering the poly-crystalline doped SiC source material growth, single crystalline epitaxy growth of fluorescent SiC, and nanofabrication of SiC to enhance the extraction efficiency for fluorescent SiC based white LEDs. 相似文献