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1.
ChemSusChem ; : e202401184, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39043624

RESUMO

Aqueous Zn-Ag batteries have been developed and commercialized for nearly a century, offering stable discharge and high specific energies. Sodium, with its lower redox potential, smaller charge-to-mass ratio, and abundant resources, presents a promising alternative to zinc. In this study, we successfully developed an all-solid-state Na-Ag battery system. This battery demonstrates stable discharge and charge voltages, low overpotential (0.27 V), high energy efficiency (>91%), and long cycle life under moderate humidity at room temperature. The reaction mechanism was elucidated through combined analyses using differential electrochemical mass spectrometry (DEMS), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Our findings indicate that metallic Ag in the cathode materials acts as an effective catalyst for the oxygen reduction reaction during the initial discharge process, forming NaOH as the discharge product. Ag is then oxidized during the charging process and recovered during discharge, serving as an active reactant in the Na-Ag battery. This work demonstrates superior performance of all-solid-state Na-Ag battery over aqueous Zn-Ag battery. Na-Ag battery may be of interest in applications with stringent requirements on stable discharge voltage and high specific energy.

2.
Front Public Health ; 10: 794967, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35223731

RESUMO

In China, early childhood care and education services for children under the age of three are neglected to some extent. Based on survey data from the Health Commission in Sichuan Province of China, this study analyzes the situation of early childhood care and education services in Sichuan through a qualitative method, using an analytical framework of matching the demand and supply. The findings reveal a mismatch between demand and supply of early childhood care and education services. This gap is likely to have a negative impact on children's self-development, family stability, and even the construction of national early childhood care and education service system. Drawing on the findings, suggestions for improving the mismatch between demand and supply are provided at the state, community and institution levels.


Assuntos
Acessibilidade aos Serviços de Saúde , Serviços de Saúde , Criança , Pré-Escolar , China , Humanos , Inquéritos e Questionários
3.
Small ; 17(30): e2100743, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34145739

RESUMO

Monolayer transition metal dichalcogenides (TMDCs) with high crystalline quality are important channel materials for next-generation electronics. Researches on TMDCs have been accelerated by the development of chemical vapor deposition (CVD). However, antiparallel domains and twin grain boundaries (GBs) usually form in CVD synthesis due to the special threefold symmetry of TMDCs lattices. The existence of GBs severely reduces the electrical and photoelectrical properties of TMDCs, thus restricting their practical applications. Herein, the epitaxial growth of single crystal MoS2 (SC-MoS2 ) monolayer is reported on Au (111) film across a two-inch c-plane sapphire wafer by CVD. The MoS2 domains obtained on Au (111) film exhibit unidirectional alignment with zigzag edges parallel to the <110> direction of Au (111). Experimental results indicated that the unidirectional growth of MoS2 domains on Au (111) is a temperature-guided epitaxial growth mode. The high growth temperature provides enough energy for the rotation of the MoS2 seeds to find the most favorable orientation on Au (111) to achieve a unidirectional ratio of over 99%. Moreover, the unidirectional MoS2 domains seamlessly stitched into single crystal monolayer without GBs formation. The progress achieved in this work will promote the practical applications of TMDCs in microelectronics.

4.
J Am Chem Soc ; 143(1): 269-278, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33373209

RESUMO

Photocatalysis provides an intriguing approach for the conversion of methane to multicarbon (C2+) compounds under mild conditions; however, with methyl radicals as the sole reaction intermediate, the current C2+ products are dominated by ethane, with a negligible selectivity toward ethylene, which, as a key chemical feedstock, possesses higher added value than ethane. Herein, we report a direct photocatalytic methane-to-ethylene conversion pathway involving the formation and dehydrogenation of alkoxy (i.e., methoxy and ethoxy) intermediates over a Pd-modified ZnO-Au hybrid catalyst. On the basis of various in situ characterizations, it is revealed that the Pd-induced dehydrogenation capability of the catalyst holds the key to turning on the pathway. During the reaction, methane molecules are first dissociated into methoxy on the surface of ZnO under the assistance of Pd. Then these methoxy intermediates are further dehydrogenated and coupled with methyl radical into ethoxy, which can be subsequently converted into ethylene through dehydrogenation. As a result, the optimized ZnO-AuPd hybrid with atomically dispersed Pd sites in the Au lattice achieves a methane conversion of 536.0 µmol g-1 with a C2+ compound selectivity of 96.0% (39.7% C2H4 and 54.9% C2H6 in total produced C2+ compounds) after 8 h of light irradiation. This work provides fresh insight into the methane conversion pathway under mild conditions and highlights the significance of dehydrogenation for enhanced photocatalytic activity and unsaturated hydrocarbon product selectivity.

5.
Molecules ; 23(8)2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30096806

RESUMO

The epidermal growth factor receptors (EGFRs), in which overexpression (known as upregulation) or overactivity have been associated with a number of cancers, has become an attractive molecular target for the treatment of selective cancers. We report here the design and synthesis of a novel series of 4,5-dihydro-1H-thieno [2',3':2,3]thiepino[4,5-c]pyrazole-3-carboxamide derivatives and the screening for their inhibitory activity on the EGFR high-expressing human A549 cell line using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). A Docking simulation was performed to fit compound 6g and gifitinib into the EGFR to determine the probable binding models, and the binding sites and modes conformation of 6g and gifitinib were exactly similar, the two compounds were stabilized by hydrogen bond interactions with MET769. Combining with the biological activity evaluation, compound 6g demonstrated the most potent inhibitory activity (IC50 = 9.68 ± 1.95 µmol·L⁻1 for A549). Conclusively, 4,5-dihydro-1H-thieno[2',3':2,3]thiepino[4,5-c]pyrazole-3-carboxamide derivatives as the EGFR tyrosine kinase inhibitors were discovered, and could be used as potential lead compounds against cancer cells.


Assuntos
Receptores ErbB/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Células A549 , Gefitinibe , Células Hep G2 , Humanos , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Pirazóis/síntese química , Pirazóis/química , Quinazolinas/química , Quinazolinas/farmacologia
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