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Transition of the radial electric field by electron cyclotron heating in the CHS heliotron/torsatron
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Given a function space spanned by a basis {?i}, we are interested in finding another basis {gi} for which the overlaps (gi | gi) assume arbitrarily prefixed values in a subset ?? of the full set of the pairs of indices (i, j). The other overlaps are let free. We show how it is possible to perform this linear transformation ?i → gi minimizing the “distortion” J = Σi(gi – ?i | gi – ?i). 相似文献
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Synthesis, Structure, and Reactivity of Bis(dialkylamino)diphosphines Starting with the aminochlorophosphines iPr2N? PCl2 1 and (iPr2N)2P? Cl 2 , the synthesis of some new functionalized aminophosphines (iPr2N)2P? SiMe3 3a , (iPr2N)2P? SnMe3 3b , (iPr2N)(DMP)P? Cl 4 , iPr2N? P(SiMe3)2 5 and iPr2N? P(SiMe3)Cl 6 is reported. Reactions of 2 with different phosphides yield the aminodiphosphines (iPr2N)2P? P(SiMe3)2 7a , (iPr2N)2P? P(SiMe2tBu)2 7b , (iPr2N)2P? PPh2 8 and (iPr2N)2P? PH2 9 . The phosphines 3a/b react with halogenophosphines to the aminohalogenodiphosphines (iPr2N)2P? PCl2 10 , (iPr2N)2P? PtBuCl 11 and (iPr2N)2P? P(NiPr2)Cl 12 . The ambivalente aminophosphine 6 gives the aminotrichlorodiphosphine Cl(iPr2N)P? PCl2 13 after condensation with PCl3, while the reactions with the corresponding lithiumphosphides yield the aminosilyldiphosphines (iPr2N)(SiMe3)P? P(SiMe3)2 14a and (iPr2N)(SiMe3)P? P(SiMe2tBu)2 14b . The aminochlorophosphines 2/4 are reductively coupled with magnesium leading to the symmetrically substituted tetraaminodiphosphines (iPr2N)2P? P(iPr2N)2 15a and DMP(iPr2N)P? P(iPr2N)DMP 15b . The functionalized aminosilyldiphosphine 7a is treated with methanol to yield the diphosphine (iPr2N)2P? PH(SiMe3) 16 and gives the lithium phosphinophosphide (iPr2N)2P? PLi(SiMe3) 17 after metallation with n-BuLi. The compounds are characterized by their NMR and mass spectra and the 31P-NMR values of the diphosphines are discussed according to their substituents. The crystal structures of 7b, 8 and 15b showing significantly differing conformations are presented. 相似文献
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Spyridon Divanis Tugce Kutlusoy Ida Marie Ingmer Boye Isabela Costinela Man Jan Rossmeisl 《Chemical science》2020,11(11):2943
Multiple strategies to overcome the intrinsic limitations of the oxygen evolution reaction (OER) have been proposed by numerous research groups. Despite the substantial efforts, the driving force required for water oxidation is largely making the reaction inefficient. In the present work, we collected published studies involving DFT calculations for the OER, with the purpose to understand why the progress made so far, for lowering the overpotential of the reaction, is relatively small. The data revealed that the universal scaling relationship between HO* and HOO* intermediates is still present and robust, despite the variety in methods and structures used for calculating the binding energies of the intermediates. On the other hand, the data did not show a clear trend line regarding the O* binding. Our analysis suggested that trends in doped semiconducting oxides behave very differently from those in other oxides. This points towards a computational challenge in describing doped oxides in a realistic manner. We propose a way to overcome these computational challenges, which can be applied to simulations corresponding to doped semiconductors in general.Multiple strategies to overcome the intrinsic limitations of the oxygen evolution reaction (OER) have been proposed by numerous research groups. 相似文献
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Volker Seibert Corinna Prohl Ida Schoultz Edward Rhee Rebecca Lopez Kareem Abderazzaq Chunshui Zhou Dieter A Wolf 《BMC biochemistry》2002,3(1):22-15
Background
SCF ubiquitin ligases share the core subunits cullin 1, SKP1, and HRT1/RBX1/ROC1, which associate with different F-box proteins. F-box proteins bind substrates following their phosphorylation upon stimulation of various signaling pathways. Ubiquitin-mediated destruction of the fission yeast cyclin-dependent kinase inhibitor Rum1p depends on two heterooligomerizing F-box proteins, Pop1p and Pop2p. Both proteins interact with the cullin Pcu1p when overexpressed, but it is unknown whether this reflects their co-assembly into bona fide SCF complexes. 相似文献10.
This stability of Sb(III) and Sb(V) species was studied during single extraction from soils by water. EDTA, diluted H2SO4 and H3PO4, and oxalic acid/oxalate solutions, with and without ascorbic acid, were used as stabilizing reagent of both Sb species. Antimony redox speciation in soil extracts was performed by selective hydride generation-atomic fluorescence spectrometry. Simulated extraction procedures (without soil) showed that, except in oxalate medium, Sb(III) was oxidized to Sb(V), and this reaction was avoided with ascorbic acid. Recovery studies from a spiked agricultural soil showed that no oxidation but sorption of Sb(III) occurred during the extraction process in water and H2SO4 medium, and quantitative oxidation in EDTA and oxalate medium. With ascorbic acid, this oxidation was totally avoided in EDTA and partially avoided in oxalate solution. A new sequential extraction procedure was proposed and applied to the fractionation and redox speciation of antimony in agricultural soils, using EDTA + ascorbic acid, pH 7 (available under complexing and moderately reducible conditions); oxalic acid/oxalate + ascorbic acid (extractable in reducible conditions) and HNO3 + HCl + HF (residual fraction). The proposed extraction scheme can provide information about the availability and mobility of antimony redox species in agricultural soils. 相似文献