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Diseases such as Alzheimer's and cancer have been linked to metabolic dysfunctions, and further understanding of metabolic pathways raises hope to develop cures for such diseases. To broaden the knowledge of metabolisms in vitro and in vivo, methods are desirable for direct probing of metabolic function. Here, we are introducing a pulsed nuclear magnetic resonance (NMR) approach to generate hyperpolarized metabolites within seconds, which act as metabolism probes. Hyperpolarization represents a magnetic resonance technique to enhance signals by over 10 000‐fold. We accomplished an efficient metabolite hyperpolarization by developing an isotopic labeling strategy for generating precursors containing a favorable nuclear spin system to add para‐hydrogen and convert its two‐spin longitudinal order into enhanced metabolite signals. The transfer is performed by an invented NMR experiment and 20 000‐fold signal enhancements are achieved. Our technique provides a fast way of generating hyperpolarized metabolites by using para‐hydrogen directly in a high magnetic field without the need for field cycling.

Obtaining stable aqueous K-ion capacitors is still challenging due to the cathode materials tended to structurally collapse after long-term cycling during large-radius K-ion insertion/extraction. In this work, three different typical MXene electrodes, i.e., Nb 2 C, Ti 2 C, and Ti 3 C 2 were individually investigated upon their electrochemical behaviors for potassium-ion (K-ion) storage. All these MXene materials exhibited pseudocapacitive-dominated behaviors, fast kinetics, and durable K-ion storage, delivering superior performance compared with other K-ion host materials. According to the experimental results, it could be ascribed to the intrinsically large interlayer distance for K-ion transport and the superb structural stability of MXene even subjected to long-term potassiation/depotassiation process.

Aiming at the dispersion of nanoparticles which are regarded as the guide of heat transfer enhancement, we investigated the heat transfer enhancement of two water-based nanofluids, namely, water-Al 2 O 3 and water-Cu mixtures. The absorbency, ζ potential, and thermal conductivity of the nanofluids were measured under different pH values and different sodium dodecylbenzene sulfonate (SDBS) dispersant concentrations. The results showed that the stability and thermal conductivity of nanofluids were highly dependent on pH values and SDBS concentrations of nanosuspensions; an optimal pH value and optimal SDBS concentration can result in the highest stability and thermal conductivity of the nanofluids. Therefore, the combined treatment with both the pH and the chemical surfactant concentration was recommended to improve the stability and thermal conductivity for practical applications of nanofluid.

A bendable/foldable/stretchable/twistable lithium-ion battery inspired by the human joint can achieve multiple deformabilities.

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host materials, including metal oxides (V 2 O 5 , [2] VO x , [3] MnO 2 , [4] and MoO 3 [5] ), metal sulfides (Mo 6 S 8 , [6] MoS 2 , [7] Ti 2 S 4 , [8] α-Ag 2 S, [9] VS 4 , [10] and VS 2 [11] ), metal selenides (Mo 6 Se 8 , [12] TiSe 2 , [13] Cu 2 Se, [14] and Ni 0.75 Fe 0.25 Se 2 [15] ), have been proposed as possible cathode candidates. In particular, copper sulfide (CuS) has recently attracted great attention because of its unique properties of nontoxicity, eco-friendliness, low cost, and high theoretical specific capacity (560 mAh g −1 ). [16] Nevertheless, CuS cathode materials are still subject to a series of unsatisfactory performances related to reversible capacity, rate capability, and cycling stability caused by the serious polarization from divalent Mg 2+ . [17] Thus, the development of suitable host materials with fast reaction kinetics is highly desired but still challenging. To solve the aforementioned issues, many strategies have been proposed and brought considerable achievement in CuS cathode materials, including: i) increased ionic diffusion kinetics through elevating working temperature, [16] ii) enhanced Mg 2+ mobility by adjusting electrode-electrolyte interface, [18] and iii) shortened Mg 2+ diffusion length via constructing suitable nanoarchitectures. [19] However, the electron and solid-state Mg 2+ transport kinetics of the most reported CuS cathode materials are still unsatisfactory. It is therefore a great challenge to effectively design CuS cathode materials with high practical capacity and long cycling life, especially at high current densities. In our previous work, [19a] although the hierarchical CuS nanosheet showed good cycling performances for rMBs (135 mAh g −1 at 200 mA g −1 upon 200 cycles), its rate capability still needs to be further improved. Heavy heteroatom substitution in transition metal sulfides is expected as an efficient route to regulate their atomic structure for providing optimized configuration for Mg 2+ uptake. [20] In particular, the fractional anionic Se-substitution to S could enlarge the Mg 2+ diffusion path and reduce their interaction with the based lattice, thereby cutting down the ionic diffusion barrier and resulting much better kinetics. [21] Till now, despite the well-known Chevrel phase Mo 6 S 8−X Se X (X = 0, 1, 2), [12,21a,22] Se-substituted copper sulfide cathode materials for rMBs have been rarely reported.Herein, we develop an efficient synthesis strategy to prepare 2D anionic Se-substituted CuS 1−x Se x nanosheets with about Rechargeable magnesium batteries (rMBs) are promising as the most ideal further energy storage systems but lack competent cathode materials due to sluggish redox reaction kinetics. Herein, developed is an anionic Sesubstitution strategy to improve the rate capability and the cycling stability of 2D CuS 1−x Se x nanosheet cathodes through an efficient microwave-induced heating method. The optimized CuS 1−x Se x (X = 0.2) nanosheet cathode can exhibit high reversible capacity of 268.5 mAh g −1 at 20 mA g −1 and good cycli...