Tropical cyclone(TC)intensity estimation is a fundamental aspect of TC monitoring and forecasting.Deep learning models have recently been employed to estimate TC intensity from satellite images and yield precise resul...Tropical cyclone(TC)intensity estimation is a fundamental aspect of TC monitoring and forecasting.Deep learning models have recently been employed to estimate TC intensity from satellite images and yield precise results.This work proposes the ViT-TC model based on the Vision Transformer(ViT)architecture.Satellite images of TCs,including infrared(IR),water vapor(WV),and passive microwave(PMW),are used as inputs for intensity estimation.Experiments indicate that combining IR,WV,and PMW as inputs yields more accurate estimations than other channel combinations.The ensemble mean technique is applied to enhance the model's estimations,reducing the root-mean-square error to 9.32 kt(knots,1 kt≈0.51 m s^(-1))and the mean absolute error to 6.49 kt,which outperforms traditional methods and is comparable to existing deep learning models.The model assigns high attention weights to areas with high PMW,indicating that PMW magnitude is essential information for the model's estimation.The model also allocates significance to the cloud-cover region,suggesting that the model utilizes the whole TC cloud structure and TC eye to determine TC intensity.展开更多
A theoretical rigid-plastic analysis for the dynamic shear failure of beams under impulsive loading is presented when using a travelling plastic shear hinge model which tabes into account material strain hardening. Th...A theoretical rigid-plastic analysis for the dynamic shear failure of beams under impulsive loading is presented when using a travelling plastic shear hinge model which tabes into account material strain hardening. The maximum dynamic shear strain and shear strain-rate can be predicted in addition to the permanent transverse deflections and other parameters. The conditions for the three modes of shear failure, i.e., excess deflection failure, excess shear strain failure and adiabatic shear failure are analyzed. The special case of an infinitesimally small plastic zone is discussed and compared with Nonaka's solution for a rigid, perfectly plastic material. The results can also be generalized to examine the dynamic response of fibre-reinforced beams.展开更多
In 1945,Porter et al.published an electon microscopy study of cultured chick fibroblasts in which they observed：＇a granular background and details of a darker lacelike reticulum which in places appears to be made up...In 1945,Porter et al.published an electon microscopy study of cultured chick fibroblasts in which they observed：＇a granular background and details of a darker lacelike reticulum which in places appears to be made up of chains of＂vesicles＂＇（Porter et al.,1945）.This constituted the first published observation of the endoplasmic reticulum（ER）and,while it was not evident at that time,this cytoplasmic system of interconnecting membrane-lined channels, comprising vesicles, tubules and cisternae, has numerous important functions.展开更多
Solar-driven energy conversion is a promising technology for a sustainable energy future and environmental remediation, and an efficient catalyst is a key factor. Recently, metal halide perovskites(MHPs) have emerged ...Solar-driven energy conversion is a promising technology for a sustainable energy future and environmental remediation, and an efficient catalyst is a key factor. Recently, metal halide perovskites(MHPs) have emerged as promising photocatalysts due to their exceptional photoelectronic properties and low-cost solution processing, enabling successful applications in H_(2) evolution, CO_(2) reduction, organic synthesis, and pollutant degradation. Despite these successes, the practical applications of MHPs are limited by their water instability. In this review, the recently developed strategies driving MHPcatalyzed reactions in aqueous media are outlined. We first articulate the structures and properties of MHPs, followed by elaborating on the origin of instability in MHPs. Then, we highlight the advances in solar-driven MHPbased catalytic systems in aqueous solutions, focusing on developing external protection strategies and intrinsically water-stable MHP materials. With each approach offering peculiar sets of advantages and challenges, we conclude by outlining potentially promising opportunities and directions for MHP-based photocatalysis research in aqueous conditions moving forward. We anticipate that this timely review will provide some inspiration for the design of MHPbased photocatalysts, manifestly stimulating their applications in aqueous environments for solar-to-chemical energy conversion.展开更多
基金Research funding for this project was provided by the National Natural Science Foundation of China(Grant Nos.42192563 and 42120104001)the Hong Kong RGC General Research Fund(Grant No.11300920)+1 种基金Anhui Provincial Natural Science Foundation(Grant Nos.2208085UQ12,2308085US01)Anhui&Huaihe River Institute of Hydraulic Research(Grant Nos.KJGG202201,KY202306)。
文摘Tropical cyclone(TC)intensity estimation is a fundamental aspect of TC monitoring and forecasting.Deep learning models have recently been employed to estimate TC intensity from satellite images and yield precise results.This work proposes the ViT-TC model based on the Vision Transformer(ViT)architecture.Satellite images of TCs,including infrared(IR),water vapor(WV),and passive microwave(PMW),are used as inputs for intensity estimation.Experiments indicate that combining IR,WV,and PMW as inputs yields more accurate estimations than other channel combinations.The ensemble mean technique is applied to enhance the model's estimations,reducing the root-mean-square error to 9.32 kt(knots,1 kt≈0.51 m s^(-1))and the mean absolute error to 6.49 kt,which outperforms traditional methods and is comparable to existing deep learning models.The model assigns high attention weights to areas with high PMW,indicating that PMW magnitude is essential information for the model's estimation.The model also allocates significance to the cloud-cover region,suggesting that the model utilizes the whole TC cloud structure and TC eye to determine TC intensity.
文摘A theoretical rigid-plastic analysis for the dynamic shear failure of beams under impulsive loading is presented when using a travelling plastic shear hinge model which tabes into account material strain hardening. The maximum dynamic shear strain and shear strain-rate can be predicted in addition to the permanent transverse deflections and other parameters. The conditions for the three modes of shear failure, i.e., excess deflection failure, excess shear strain failure and adiabatic shear failure are analyzed. The special case of an infinitesimally small plastic zone is discussed and compared with Nonaka's solution for a rigid, perfectly plastic material. The results can also be generalized to examine the dynamic response of fibre-reinforced beams.
文摘In 1945,Porter et al.published an electon microscopy study of cultured chick fibroblasts in which they observed：＇a granular background and details of a darker lacelike reticulum which in places appears to be made up of chains of＂vesicles＂＇（Porter et al.,1945）.This constituted the first published observation of the endoplasmic reticulum（ER）and,while it was not evident at that time,this cytoplasmic system of interconnecting membrane-lined channels, comprising vesicles, tubules and cisternae, has numerous important functions.
基金City University of Hong Kong,Grant/Award Number:SIRG 7020022Hong Kong Research Grant Council(RGC),Grant/A ward Numbers:GRFCityU 11305419,GRF CityU 11306920,GRF CityU 11308721,GRF CityU11316522。
文摘Solar-driven energy conversion is a promising technology for a sustainable energy future and environmental remediation, and an efficient catalyst is a key factor. Recently, metal halide perovskites(MHPs) have emerged as promising photocatalysts due to their exceptional photoelectronic properties and low-cost solution processing, enabling successful applications in H_(2) evolution, CO_(2) reduction, organic synthesis, and pollutant degradation. Despite these successes, the practical applications of MHPs are limited by their water instability. In this review, the recently developed strategies driving MHPcatalyzed reactions in aqueous media are outlined. We first articulate the structures and properties of MHPs, followed by elaborating on the origin of instability in MHPs. Then, we highlight the advances in solar-driven MHPbased catalytic systems in aqueous solutions, focusing on developing external protection strategies and intrinsically water-stable MHP materials. With each approach offering peculiar sets of advantages and challenges, we conclude by outlining potentially promising opportunities and directions for MHP-based photocatalysis research in aqueous conditions moving forward. We anticipate that this timely review will provide some inspiration for the design of MHPbased photocatalysts, manifestly stimulating their applications in aqueous environments for solar-to-chemical energy conversion.
