A 3D porous sulfur/graphene@g‐C3N4 (S/GCN) hybrid sponge, which can be directly applied as a free‐standing cathode for Li–S batteries, is realized via a microemulsion assisted assembly approach. In ...this strategy, the interior oil emulsion droplets serve as soft templates to form pores to accommodate sulfur and the hydrophilic GCN stacks around oil droplets to assemble into a crosslinked 3D network. Through this microemulsion encapsulation route, S/GCN cathodes with a sulfur loading as high as 82 wt% can be achieved. Furthermore, the enriched N‐sites in GCN macropores offer numerous adhesion sites for polysulfides, realizing a “physical‐chemical” dual‐confinement for polysulfides from diffusion. Moreover, the robust and highly porous 3D graphene frameworks render efficient electron/Li+ transport pathways for fast kinetics as well as good structure integrity. Consequently, in comparison to the conventional G‐sponge/Li2Sn catholyte system, S/GCN delivers a higher specific capacity, superior high‐rate capability (612 mA h g−1 at 10 C), and alleviated anode corrosion issues. Particularly, an energy density as high as 1493 W h kg−1 (calculated on the total weight of the cathode) and an extremely low capacity fading rate of 0.017% per cycle over 800 cycles at 0.3 C are achieved.
Oil‐in‐water microemulsion assembly of 3D porous S/graphene@C3N4 (S/GCN) sponge is proposed as a free‐standing cathode for Li–S batteries. The oil emulsions serve as templates for macropores to accommodate sulfur, while the GCN stacks around oil droplets to assemble into interlinked 3D network. The S/GCN exhibits superior high‐rate capability (612 mA h g−1 at 10 C) and stable long‐term cycling over 800 cycles.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Deaminative functionalization of aliphatic primary amines has great synthetic utility. Herein, we describe a Ni-catalyzed reductive deaminative cross-electrophile coupling reaction between Katritzky ...salts and aromatic amides. This work provides examples of the synthesis of various ketones from alkylpyridinium salts, including both primary and secondary alkylamines. Given its mild reaction conditions and high functional group tolerance, this cross-coupling strategy is expected to be useful for late-stage functionalization of complex compounds.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
Tensor-network-based methods are promising candidates to solve quantum impurity problems (QIP). They are free of sampling noises and the sign problem compared to state-of-the-art ...continuous-time quantum Monte Carlo methods. Recent progress made in tensor-network-based impurity solvers is to use the Feynman–Vernon influence functional to integrate out the bath analytically, retaining only the impurity dynamics and representing it compactly as a matrix product state. The recently proposed Grassmann time-evolving matrix product operator (GTEMPO) method is one of the representative methods in this direction. In this work, we systematically study the performance of GTEMPO in solving equilibrium QIPs at a finite temperature with a semicircular spectrum density of the bath. Our results show that its computational cost would generally increase as the temperature goes down and scale exponentially with the number of orbitals. In particular, the single-orbital Anderson impurity model can be efficiently solved with this method, for two orbitals we estimate that one could possibly reach inverse temperature
β
≈ 20 if high-performance computing techniques are utilized, while beyond that only very high-temperature regimes can be reached in the current formalism. Our work paves the way to apply GTEMPO as an imaginary-time impurity solver.
Activity‐based E2 conjugating enzyme (E2)‐ubiquitin (Ub) probes have recently emerged as effective tools for studying the molecular mechanism of E3 ligase (E3)‐catalyzed ubiquitination. However, the ...preparation of existing activity‐based E2‐Ub probes depends on recombination technology and bioconjugation chemistry, limiting their structural diversity. Herein we describe an expedient total chemical synthesis of an E2 enzyme variant through a hydrazide‐based native chemical ligation, which enabled the construction of a structurally new activity‐based E2‐Ub probe to covalently capture the catalytic site of Cys‐dependent E3s. Chemical cross‐linking coupled with mass spectrometry (CXMS) demonstrated the utility of this new probe in structural analysis of the intermediates formed during Nedd4 and Parkin‐mediated transthiolation. This study exemplifies the utility of chemical protein synthesis for the development of protein probes for biological studies.
A structurally new activity‐based E2‐Ub probe that closely resembles the native E2∼Ub thioester has been developed and used for structural analysis of Cys‐dependent E3 ligases‐catalyzed transthiolation. This new probe is readily prepared in an expedient total chemical synthesis of atomically‐tailored E2 enzyme variant using hydrazide‐based native chemical ligation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Recent works have shown that generic local Hamiltonians can be efficiently inferred from local measurements performed on their eigenstates or thermal states. Realistic quantum systems are often ...affected by dissipation and decoherence due to coupling to an external environment. This raises the question whether the steady states of such open quantum systems contain sufficient information allowing for full and efficient reconstruction of the system's dynamics. We find that such a reconstruction is possible for generic local Markovian dynamics. We propose a recovery method that uses only local measurements; for systems with finite-range interactions, the method recovers the Lindbladian acting on each spatial domain using only observables within that domain. We numerically study the accuracy of the reconstruction as a function of the number of measurements, type of open-system dynamics and system size. Interestingly, we show that couplings to external environments can in fact facilitate the reconstruction of Hamiltonians composed of commuting terms.
Trade-induced carbon transfer has emerged as a significant contributor to global carbon emissions, with international carbon competitiveness playing a pivotal role in this transfer. Based on a sample ...of 43 major economies from 2000 to 2014, this paper empirically examines the influence of digital transformation on the international carbon competitiveness of the manufacturing sector. The results reveal a substantial enhancement in manufacturing's international carbon competitiveness facilitated by digital transformation. Three primary mechanisms drive this enhancement: the scale effect, advancement of the forward global value chains position, and an improved energy structure. Notably, both domestic and foreign sources of digital transformation bolster the international carbon competitiveness of domestic manufacturing. Furthermore, the enabling of segmented digital industry strengthens this competitiveness, especially in publishing, programming, and broadcasting activities. This paper enriches the research on the environmental implications of digital transformation and offers insights for policymakers aiming to boost international carbon competitiveness and promote greener industrial growth.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel copper‐catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides has been developed. The regioselectivity of the alkylboration was controlled by subtle ...differences in the ligand structure. The reaction thus enables the practical, regiodivergent synthesis of two different alkyl boronic esters with complex structures from a single alkene.
One way or another: The copper‐catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides is described. The regioselectivity of the carboboration can be controlled by fine‐tuning the ligand structure.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Characterization of non-Markovian open quantum dynamics is both of theoretical and practical relevance. In a seminal work Phys. Rev. Lett. 120, 040405 (2018), a necessary and sufficient quantum ...Markov condition is proposed, with a clear operational interpretation and correspondence with the classical limit.
Here we propose two non-Markovianity measures for general open quantum dynamics, which are fully reconciled with the Markovian limit and can be efficiently calculated based on the multi-time quantum measurements of the system. A heuristic algorithm for reconstructing the underlying open quantum dynamics is proposed, whose complexity is directly related to the proposed non-Markovianity measures. The non-Markovianity measures and the reconstruction algorithm are demonstrated with numerical examples, together with a careful reexamination of the non-Markovianity in quantum dephasing dynamics.
An unprecedented Pd‐catalyzed regioselective activation of gem‐difluorinated cyclopropanes induced by CC bond cleavage is reported. It provides a general and efficient access to a variety of ...2‐fluoroallylic amines, ethers, esters, and alkylation products in high Z‐selectivity, which are important skeletons in many biologically active molecules. In addition, the transformation represents the first general application of gem‐difluorinated cyclopropanes as reaction partners in transition‐metal‐catalyzed cross‐coupling reaction.
CC bond cleavage under Pd catalysis induces a regioselective activation of gem‐difluorinated cyclopropanes. The reaction provides access to a variety of 2‐fluoroallylic scaffolds with high Z‐selectivity and represents the first general application of gem‐difluorinated cyclopropanes as reaction partners in transition‐metal‐catalyzed cross‐coupling reactions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Recently, metric learning and similarity learning have attracted a large amount of interest. Many models and optimization algorithms have been proposed. However, there is relatively little work on ...the generalization analysis of such methods. In this paper, we derive novel generalization bounds of metric and similarity learning. In particular, we first show that the generalization analysis reduces to the estimation of the Rademacher average over “sums-of-i.i.d.” sample-blocks related to the specific matrix norm. Then, we derive generalization bounds for metric/similarity learning with different matrix-norm regularizers by estimating their specific Rademacher complexities. Our analysis indicates that sparse metric/similarity learning with
L
1
-norm regularization could lead to significantly better bounds than those with Frobenius-norm regularization. Our novel generalization analysis develops and refines the techniques of U-statistics and Rademacher complexity analysis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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