The key issue holding back the application of solid polymeric electrolytes in high‐energy density lithium metal batteries is the contradictory requirements of high ion conductivity and mechanical ...stability. In this work, self‐healable solid polymeric electrolytes (SHSPEs) with rigid‐flexible backbones and high ion conductivity are synthesized by a facile condensation polymerization approach. The all‐solid Li metal full batteries based on the SHSPEs possess freely bending flexibility and stable cycling performance as a result of the more disciplined metal Li plating/stripping, which have great implications as long‐lifespan energy sources compatible with other wearable devices.
Solid but flexible: A self‐healing solid polymer electrolyte (featuring fast self‐healing within 60 s after a deep cut with a blade) endows solid Li metal full batteries with freely bending flexibility and superior cycling stability as demonstrated by the small capacity decay of 0.1 % per cycle over 100 cycles.
Hydroxytyrosol is an antioxidant free radical scavenger that is biosynthesized from tyrosine. In metabolic engineering efforts, the use of the mouse tyrosine hydroxylase limits its production. Here, ...we design an efficient whole-cell catalyst of hydroxytyrosol in Escherichia coli by de-bottlenecking two rate-limiting enzymatic steps. First, we replace the mouse tyrosine hydroxylase by an engineered two-component flavin-dependent monooxygenase HpaBC of E. coli through structure-guided modeling and directed evolution. Next, we elucidate the structure of the Corynebacterium glutamicum VanR regulatory protein complexed with its inducer vanillic acid. By switching its induction specificity from vanillic acid to hydroxytyrosol, VanR is engineered into a hydroxytyrosol biosensor. Then, with this biosensor, we use in vivo-directed evolution to optimize the activity of tyramine oxidase (TYO), the second rate-limiting enzyme in hydroxytyrosol biosynthesis. The final strain reaches a 95% conversion rate of tyrosine. This study demonstrates the effectiveness of sequentially de-bottlenecking rate-limiting steps for whole-cell catalyst development.
Layered titanium carbide (Ti3C2) has been synthesized by exfoliation of ternary carbides Ti3AlC2 and evaluated as working electrodes with different mass loading from 1.8 mg to 7.6 mg. The effect of ...mass loading on the electrochemical properties of Ti3C2 electrodes was studied by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and impedance spectrum test. With increasing of Ti3C2 mass from 1.8 to 7.6 mg/cm2 in electrode, the specific capacitance calculated from the CV curves at 2 mV/s decreases at first from 117 to 78 F/g then maintains at 76 F/g, while areal capacitance increases from 211 to 579 mF/cm2. Moreover, both electrodes with low mass loading (1.8 mg) and large mass loading (7.6 mg) have delivered good cycling performances with capacitance retention of 97% and 98% after 10000 cycles. These results indicate that large mass loading electrode retains high specific capacitance and good cycling stability, due to the excellent electronic conductivity and layered structure of Ti3C2.
•Ti3C2 electrodes with different mass loading have been investigated.•Large mass loading electrode retains high specific capacitance and cycling stability.•Possible mechanism for the high capacitive performance was proposed.•The intercalation pseudocapacitance occurred in the Ti3C2 materials.
The magnetic relaxation dynamics of low-coordinate DyIII and ErIII complexes, namely three-coordinate ones with an equatorially coordinated triangle geometry and five-coordinate ones with a trigonal ...bipyramidal geometry, have been exploited for the first time. The three-coordinate Er-based complex is the first equatorially coordinated mononuclear Er-based single-molecule magnet (SMM) corroborating that simple models can effectively direct the design of target SMMs incorporating 4f-elements.
Single-molecule toroics (SMTs) are defined, by analogy with single-molecule magnets, as bistable molecules with a toroidal magnetic state, and seem to be most promising for future applications in ...quantum computing and information storage and use as multiferroic materials with magnetoelectric effect. As an interdisciplinary research area that spans chemistry, physics and material sciences, synthetic chemists have produced systems suitable for detailed study by physicists and materials scientists, while
ab initio
calculations have been playing a major role in the detection of toroidal magnetization and the advancement of this field. In this tutorial review, we demonstrate the research developed in the fascinating and challenging field of molecular-based SMTs with particular focus on how recent studies tend to address the issue of toroidal arrangement of the magnetic moment in these systems. Herein, nine typical SMTs are summarized, showing that the assembly of wheel-shaped complexes with the high symmetry of the molecule unit and strong intra-molecular dipolar interactions using strong anisotropy metal ions represents the most promising route toward the design of a toroidal moment. Furthermore, the linkage of such robust toroidal moment units with ferromagnetic type through appropriate bridging ligands enhances the toroidal magnetic moment per unit cell.
Bistable molecules with a toroidal magnetic state (single-molecule toroics) are promising for applications in quantum computing and information storage.
In situ
monitoring of the location and transportation of bioactive molecules is essential for deciphering diverse biological events in the field of biomedicine. In addition, obtaining the
in situ
...information of lesions will provide a clear perspective for surgeons to perform precise resection in clinical surgery. Notably, delivering drugs or operating photodynamic therapy/photothermal therapy
in situ
by labeling the lesion regions of interest can improve treatment and reduce side effects
in vivo
. In various advanced imaging and therapy modalities, optical theranostic agents based on organic small molecules can be conveniently modified as needed and can be easily internalized into cells/lesions in a non-invasive manner, which are prerequisites for
in situ
bioimaging and precision treatment. In this tutorial review, we first summarize the
in situ
molecular immobilization strategies to retain small-molecule agents inside cells/lesions to prevent their diffusion in living organisms. Emphasis will be focused on introducing the application of these strategies for
in situ
imaging of biomolecules and precision treatment, particularly pertaining to why targeting therapy
in situ
is required.
The straw return method has been increasingly implemented in rice production in Northeast China. In-depth studies on the characteristics of rice straw decomposition are of great importance for ...achieving sustainable agricultural development. In this study, the nylon mesh bagging method was used to study the patterns of rice straw decomposition and nutrient release during a 5-year period of rice growth. The results showed that straw decomposition occurred mainly during the first 3 years after straw return, with the cumulative amount of decomposition reaching 77.0%, and that the rate of straw decomposition decreased linearly with time. The release of carbon, nitrogen, cellulose and hemicellulose occurred mainly during the first and second years after straw return. Moreover, the release of phosphorus and potassium occurred mainly during the first month after straw return, and lignin was released at various rates throughout the entire study period. These results indicated that straw returned to the soil acts both as a source of phosphorus and potassium in the short term and as a source of nitrogen and carbon in the long term during the rice growing season in Northeast China.
With a remarkably high energy density and high safety, all-solid-state lithium-sulfur (ASSLS) batteries have emerged as promising next-generation energy storage systems. Direct tracking of the ...structural evolution at the solid-solid interfaces in an ASSLS battery is highly significant for deep understanding of the reaction mechanism to further improve the electrochemical performance. Herein, we present
in situ
monitoring of the evolution processes at both the cathode/electrolyte and anode/electrolyte interfaces in working ASSLS batteries
via
real-time optical microscope (OM) imaging. An irreversible transformation from bright-white to dark-brown in the polymer-ceramic composite electrolyte was directly captured upon discharge/charge, which indicates a shuttling process of polysulfides in the solid-state electrolyte further supported by XPS and Raman analyses. Furthermore, the
in situ
visualization of the temperature dependency of structural evolution clearly reveals that temperature greatly influences the polysulfide shuttling, irreversible volume-change of solid-state electrolytes and volume expansion of Li metal, which are directly correlated with the degradation of battery performance. These results provide a deep insight into the evolution processes of both structure and component in a working ASSLS battery, which could guide one to explore the electrochemical reactions at solid-solid interfaces and failure mechanism to design high performance lithium-sulfur batteries.
In situ
monitoring of the interfacial processes in working all-solid-state lithium-sulfur batteries provides deep insights into the degradation mechanisms and temperature dependence.
A smart classroom is a new type of teaching mode based on dynamic data analysis, which is a major change in the teaching mode, and the application of smart classrooms in ideological education can ...significantly enhance the relevance and effectiveness of ideological and political education in colleges and universities. This paper constructs a smart classroom teaching model for college ideology and politics based on the theory and technology of smart classrooms and designs a smart classroom teaching evaluation model to assess its practical application effect. The model design is combined with the expert consultation method to establish a comprehensive evaluation index system and calculate the weights of each index. Finally, the evaluation of the actual application effect of smart classroom teaching is carried out. The results show that the weights of the two first-level indexes, namely, “scientific method” and “patriotism”, are the highest, respectively 0.5 and 0.5, and the weights of the two first-level indexes are the highest. The results show that among the first-level indicators, the two first-level indicators of “scientific method” and “patriotism” have the highest weights, respectively 0.214 and 0.186. The weights of “classroom performance”, “homework,” and “practical activities” are lower, respectively 0.077, 0.073, and 0.073. Applying this paper's Civics Smart Classroom Teaching Model to actual Civics teaching, the model evaluation results show that the scores of the secondary indicators have increased, of which “asking questions” has increased from 3.54 to 3.98, an increase of 12.43%. In contrast, the indicator of “ extracurricular activities” has risen from 3.54 to 3.98, an increase of 12.43%, and the indicator of “extracurricular activities” has increased from 0.077 to 3.98. Extracurricular activities” indicator rose from 4.36 to 4.47, an increase of 2.52%. This paper designs an intelligent classroom teaching model for college civic education with good practical application effects.
Genetic diversity is a result of evolution, enabling multiple ways for one particular physiological activity. Here, we introduce this strategy into bioengineering. We design two hydroxytyrosol ...biosynthetic pathways using tyrosine as substrate. We show that the synthetic capacity is significantly improved when two pathways work simultaneously comparing to each individual pathway. Next, we engineer flavin-dependent monooxygenase HpaBC for tyrosol hydroxylase, tyramine hydroxylase, and promiscuous hydroxylase active on both tyrosol and tyramine using directed divergent evolution strategy. Then, the mutant HpaBCs are employed to catalyze two missing steps in the hydroxytyrosol biosynthetic pathways designed above. Our results demonstrate that the promiscuous tyrosol/tyramine hydroxylase can minimize the cell metabolic burden induced by protein overexpression and allow the biosynthetic carbon flow to be divided between two pathways. Thus, the efficiency of the hydroxytyrosol biosynthesis is significantly improved by rearranging the metabolic flux among multiple pathways.
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