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When the onshore accurate current (AC) grid connected to the offshore wind power voltage source converter-based high voltage direct current (VSC-HVDC) transmission system fails,the surplus power continuously output by the wind farm causes DC overvoltage. The most effective way to solve the surplus power is to use the energy dissipation device to discharge the surplus power. A centralized DC energy dissipation device scheme based on half-bridge sub-modules is proposed to solve the problems of large switching power shock when power devices directly connected in series,difficulty in switching devices at the same time and high cost of distributed DC energy dissipation device. The parameter design method and control strategy of the proposed topology are studied. The solution can overcome the technical difficulties and risks of direct series connection of large-scale power devices,and can gradually reduce the resistance voltage change rate by switching sub-modules,thereby reducing the impact of power discharge on the DC system and the difficulty of manufacturing unloading resistors. Compared with the distributed DC energy dissipation device,the proposed scheme only uses the centralized resistance and omits the bleeder branch in the sub-modules,which greatly reduces the equipment cost. The fault ride-through simulation of the offshore wind power VSC-HVDC transmission system is carried out on the PSCAD platform. And the results show that the proposed centralized DC energy dissipation device topology and control scheme have good performance.

Nanozymes have obvious advantages in improving the efficiency of cancer treatment. However, due to the lack of tissue specificity, low catalytic efficiency, and so on, their clinical applications are limited. Herein, the nanoplatform CeO2@ICG@GOx@HA (CIGH) with self‐accelerated cascade reactions is constructed. The as‐prepared nanozyme shows the superior oxidase (OXD)‐like, superoxide dismutase (SOD)‐like, catalase (CAT)‐like and peroxidase (POD)‐like activities. At the same time, under 808 nm near‐infrared (NIR) irradiation, the photodynamic and photothermal capabilities are also significantly enhanced due to the presence of indocyanine green (ICG). We demonstrate that the nanozyme CIGH can efficiently accumulate in the tumor and exhibit amplified cascade antitumor effects with negligible systemic toxicity through the combination of photodynamic therapy (PDT), photothermal therapy (PTT), chemodynamic therapy (CDT) and starvation therapy. The nanozyme prepared in this study provides a promising candidate for catalytic nanomedicines for efficient tumor therapy. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Hierarchically porous materials (HP materials) are believed one of the most hopeful matrix materials because of their distinctive multimodal pore structures and tremendous application potentials in the field of biomedicine. However, green and facile synthesis of hierarchically porous nanomaterials with beneficial water dispersibility and biocompatibility is still a great challenge. Herein, a novel biomimetic strategy is proposed to prepare the cell‐tailored double‐shelled HPCaCO3/CaF2 hollow nanospheres under the mediation of yeast cells. The biomolecules derived from the secretion of yeast cells are used as conditioning and stabilizing agents to control the biosynthesis of the HPCaCO3/CaF2 materials, which exhibit excellent water dispersibility and favorable biocompatibility. The double‐shelled CaCO3/CaF2 nanospheres hold hierarchically porous structure and have abundant pore channel and large specific surface area, showing high drug‐loading and a prolonged drug sustainable release profile by the pore‐by‐pore diffusion pattern of the hierarchical pores. Otherwise, the HPCaCO3 with pH‐sensitivity could controllably release drug doxorubicin hydrochloride (DOX) at the acidic tumor microenvironment. Both in vitro and in vivo results demonstrate that HPCaCO3/CaF2 has the sustainable pH‐sensitive drug release property, showing an enhanced therapeutic effect. Summarily, this study provides a biomimetic strategy to synthesize the hierarchically porous double‐shelled hollow nanomaterials for applying in sustainable drug delivery system. [ABSTRACT FROM AUTHOR]

Digital transformation serves as a crucial foundation for enterprises to achieve business and trade digitisation, as well as to drive industrial upgrading and high-quality economic development. This paper explores the impact and mechanism of the ‘Specialized and New’ policy on enterprise digital transformation, utilising the policy established in 2019 as a quasi-natural experiment and leveraging data from China’s A-share listed companies between 2017 and 2021. We employ difference-in-differences model to investigate the effects and underlying mechanisms of the ‘Specialized and New’ policy on digital transformation. Our results demonstrate that the ‘Specialized and New’ policy significantly promotes the process of enterprise digital transformation. Heterogeneity analysis reveals that the policy has a more pronounced effect on the digital transformation of non-state-owned enterprises, medium-sized enterprises, and enterprises with high management efficiency. In-depth mechanistic tests reveal that the ‘Specialized and New’ policy facilitates digital transformation through three pathways: enhancing research and development capabilities, introducing government subsidies, and reducing financing constraints. The policy is relatively new and less well researched, so the findings of this paper provide valuable insights and lessons for domestic and foreign policymakers, which can help in the replication of subsequent policies as well as the development and transformation of enterprises. [ABSTRACT FROM AUTHOR]

Gold chloride clusters play an important role in catalysis and materials chemistry. Due to the diversity of their species and isomers, there is still a dearth of structural studies at the molecular level. In this work, anions of AunCln+3- and AunCln+5- (n = 2-4) clusters were obtained by laser desorption/ionization mass spectrometry (LDI MS), and the most stable isomers of AunCln+3- were determined after a thorough search and optimization at the TPSSh/aug-cc-pVTZ/ECP60MDF level. The results indicate that all isomers with the lowest energy have a planar zigzag skeleton. In each species, there is one Au(III) atom at the edge connected with four Cl atoms, which sets it from the other Au(I) atoms. Four growth pathways for AunCln+3- (n = 2-7) clusters are proposed (labelled R1, R2, R3 and R4). They are all associated with an aurophilic contact and are exothermic. The binding energies tend to stabilize at --41kcal/mol when the size of the cluster increases in all pathways. The pathway R1, which connects all the most stable isomers of the respective clusters, is characterized by cluster growth due to aurophilic interactions at the terminal atom of Au(I) in the zigzag chains. In the pathway of R4 involving Au-Au bonding in its initial structures (n < 3), the distance between intermediate gold atoms grows with cluster size, ultimately resulting in the transfer of the intermediate Au-Au bonding into aurophilic interaction. The size effect on the structure and aurophilic interactions of these clusters will be better understood based on these discoveries, potentially providing new insights into the active but elusive chemical species involved in the corresponding catalytic reactions or nanoparticle synthesis processes. [ABSTRACT FROM AUTHOR]

Gold chloride clusters play an important role in catalysis and materials chemistry. Due to the diversity of their species and isomers, there is still a dearth of structural studies at the molecular level. In this work, anions of AunCln+3- and AunCln+5- (n = 2-4) clusters were obtained by laser desorption/ionization mass spectrometry (LDI MS), and the most stable isomers of AunCln+3- were determined after a thorough search and optimization at the TPSSh/aug-cc-pVTZ/ECP60MDF level. The results indicate that all isomers with the lowest energy have a planar zigzag skeleton. In each species, there is one Au(III) atom at the edge connected with four Cl atoms, which sets it from the other Au(I) atoms. Four growth pathways for AunCln+3- (n = 2-7) clusters are proposed (labelled R1, R2, R3 and R4). They are all associated with an aurophilic contact and are exothermic. The binding energies tend to stabilize at -- 41kcal/mol when the size of the cluster increases in all pathways. The pathway R1, which connects all the most stable isomers of the respective clusters, is characterized by cluster growth due to aurophilic interactions at the terminal atom of Au(I) in the zigzag chains. In the pathway of R4 involving Au-Au bonding in its initial structures (n < 3), the distance between intermediate gold atoms grows with cluster size, ultimately resulting in the transfer of the intermediate Au-Au bonding into aurophilic interaction. The size effect on the structure and aurophilic interactions of these clusters will be better understood based on these discoveries, potentially providing new insights into the active but elusive chemical species involved in the corresponding catalytic reactions or nanoparticle synthesis processes. [ABSTRACT FROM AUTHOR]