Structural health monitoring is a research hotspot in engineering, and structural damage identification is one of the key problems in structural health monitoring research. This paper proposes a ...study on structural damage identification and localization based on artificial neural networks, and for the problem that the learning convergence speed of the BP neural network is too slow, a genetic algorithm is used to optimize the update of weights and thresholds during training and learning. In the finite element simulation, the structure's primary and secondary damage are taken as input nodes, and the optimized GA-BP neural network is used for training and identification. For the localization recognition of the primary damage of the structure, the maximum recognition relative errors of both the BP neural network and the GA-BP neural network did not exceed 5%, but the latter's accuracy was 2.63% higher than that of the former. For the localization recognition of secondary damage, the GA-BP neural network can effectively recognize 90% of the samples. The artificial neural network-based structural damage recognition localization has high recognition efficiency and accuracy, which is conducive to improving the robustness of the structural damage recognition system and is of significant help to real-time structural health monitoring.
In the new era, cultural consumption has become an important aspect of promoting economic development, and how to correctly grasp the development direction of cultural industry and the direction of ...consumption is the key to achieving a modern and strong country. This paper uses the cultural consumption data of 31 provinces nationwide from 2015 to 2019 to analyze the current situation of cultural consumption and analyze the differences in cultural consumption and its influencing factors among regions nationwide. The study shows that the value added of cultural industry, GDP per capita and disposable income per capita have significant positive effects on regional cultural consumption levels, the consumer price index has a significant inverse effect on regional cultural consumption levels, the education level per capita has the most significant effect on regional cultural consumption differences, and government input has less influence on regional cultural consumption levels. Therefore, in order to further improve the level of cultural consumption in China, we should focus on regions with slightly backward economy, increase the government’s financial investment in cultural industry, improve the system, and at the same time, continuously improve the cultural literacy of residents and increase their income to jointly promote cultural development.
Although the field of polymer solar cell has seen much progress in device performance in the past few years, several limitations are holding back its further development. For instance, current ...high-efficiency (>9.0%) cells are restricted to material combinations that are based on limited donor polymers and only one specific fullerene acceptor. Here we report the achievement of high-performance (efficiencies up to 10.8%, fill factors up to 77%) thick-film polymer solar cells for multiple polymer:fullerene combinations via the formation of a near-ideal polymer:fullerene morphology that contains highly crystalline yet reasonably small polymer domains. This morphology is controlled by the temperature-dependent aggregation behaviour of the donor polymers and is insensitive to the choice of fullerenes. The uncovered aggregation and design rules yield three high-efficiency (>10%) donor polymers and will allow further synthetic advances and matching of both the polymer and fullerene materials, potentially leading to significantly improved performance and increased design flexibility.
It is well known that in addition to bound water in the reservoir, formation water mainly exists in the form of edge water and bottom water. Fractured buried hill metamorphic rock reservoirs are ...generally bottom-water reservoirs. In fractured reservoirs, rock blocks are cut by fractures and oil and water are distributed in fractures. Due to the low capillary pressure of fractures, the oil-water transition zone is also small. In the same fault block, there is relatively uniform oil-water interface. And oil-water interface to judge correctly or not will directly related to the determination of oil-bearing area and effective thickness division and well placement, thus correctly determine the position of the oil-water interface of oil field development is of great significance, through the variation of oil-water interface also presumably or some guidance on the seismic section can't precisely divide the small fault.
Abstract
Photoelectrochemical water splitting provides a promising solution for harvesting and storing solar energy. As the best-performing oxide photocathode, the Cu
2
O photocathode holds the ...performance rivaling that of many photovoltaic semiconductor-based photocathodes through continuous research and development. However, the state-of-the-art Cu
2
O photocathode employs gold as the back contact which can lead to considerable electron-hole recombination. Here, we present a Cu
2
O photocathode with overall improved performance, enabled by using solution-processed CuSCN as hole transport material. Two types of CuSCN with different structures are synthesized and carefully compared. Furthermore, detailed characterizations reveal that hole transport between Cu
2
O and CuSCN is assisted by band-tail states. Owing to the multiple advantages of applying CuSCN as the hole transport layer, a standalone solar water splitting tandem cell is built, delivering a solar-to-hydrogen efficiency of 4.55%. Finally, approaches towards more efficient dual-absorber tandems are discussed.
Lithium–sulfur batteries (LSBs) with superior energy density are among the most promising candidates of next‐generation energy storage techniques. As the key step contributing to 75% of the overall ...capacity, Li2S deposition remains a formidable challenge for LSBs applications because of its sluggish kinetics. The severe kinetic issue originates from the huge interfacial impedances, indicative of the interface‐dominated nature of Li2S deposition. Accordingly, increasing efforts have been devoted to interface engineering for efficient Li2S deposition, which has attained inspiring success to date. However, a systematic overview and in‐depth understanding of this critical field are still absent. In this review, the principles of interface‐controlled Li2S precipitation are presented, clarifying the pivotal roles of electrolyte–substrate and electrolyte–Li2S interfaces in regulating Li2S depositing behavior. For the optimization of the electrolyte–substrate interface, efforts on the design of substrates including metal compounds, functionalized carbons, and organic compounds are systematically summarized. Regarding the regulation of electrolyte–Li2S interface, the progress of applying polysulfides catholytes, redox mediators, and high‐donicity/polarity electrolytes is overviewed in detail. Finally, the challenges and possible solutions aiming at optimizing Li2S deposition are given for further development of practical LSBs. This review would inspire more insightful works and, more importantly, may enlighten other electrochemical areas concerning heterogeneous deposition processes.
Li2S deposition, the final discharge step contributing 75% capacity to Li–S batteries, remains a formidable issue due to its sluggish kinetics. The inferior deposition kinetics stem from the huge interfacial impedances, suggesting its interface‐dominated nature. In this review, the progress and outlook of interface engineering for Li2S deposition, associated with the underlying mechanisms and potential problem‐solving strategies, are reviewed.
Mortise‐and‐tenon joints have been widely used for thousands of years in wooden architectures in virtue of their artistic and functional performance. However, imitation of similar structural and ...mechanical design philosophy to construct mechanically adaptive materials at the molecular level is a challenge. Herein, we report a mortise‐and‐tenon joint inspired mechanically interlocked network (MIN), in which the 2rotaxane crosslink not only mimics the joint in structure, but also reproduces its function in modifying mechanical properties of the MIN. Benefiting from the hierarchical energy dissipative ability along with the controllable intramolecular movement of the mechanically interlocked crosslink, the resultant MIN simultaneously exhibits notable mechanical adaptivity and structural stability in a single system, as manifested by decent stiffness, strength, toughness, and deformation recovery capacity.
We demonstrated that the delicate mortise‐and‐tenon joint was precisely mimicked to construct a mechanically interlocked network (MIN), which simultaneously integrates incompatible mechanical adaptivity, robustness, and dynamic stability in a single system.
As a result of their attractive optoelectronic properties, metal halide APbI3 perovskites employing formamidinium (FA+) as the A cation are the focus of research. The superior chemical and thermal ...stability of FA+ cations makes α‐FAPbI3 more suitable for solar‐cell applications than methylammonium lead iodide (MAPbI3). However, its spontaneous conversion into the yellow non‐perovskite phase (δ‐FAPbI3) under ambient conditions poses a serious challenge for practical applications. Herein, we report on the stabilization of the desired α‐FAPbI3 perovskite phase by protecting it with a two‐dimensional (2D) IBA2FAPb2I7 (IBA=iso‐butylammonium overlayer, formed via stepwise annealing. The α‐FAPbI3/IBA2FAPb2I7 based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23 %. In addition, it showed excellent operational stability, retaining around 85 % of its initial efficiency under severe combined heat and light stress, that is, simultaneous exposure with maximum power tracking to full simulated sunlight at 80 °C over 500 h.
The desired α‐FAPbI3 perovskite phase is stabilized by protecting it with a two‐dimensional (2D) IBA2FAPb2I7 (IBA=iso‐butylammonium) overlayer, formed via stepwise annealing. The α‐FAPbI3/IBA2FAPb2I7‐based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23 %. It showed excellent operational stability, retaining around 85 % of its initial efficiency under severe combined heat and light stress.
The use of deep learning (DL) for the analysis and diagnosis of biomedical and health care problems has received unprecedented attention in the last decade. The technique has recorded a number of ...achievements for unearthing meaningful features and accomplishing tasks that were hitherto difficult to solve by other methods and human experts. Currently, biological and medical devices, treatment, and applications are capable of generating large volumes of data in the form of images, sounds, text, graphs, and signals creating the concept of big data. The innovation of DL is a developing trend in the wake of big data for data representation and analysis. DL is a type of machine learning algorithm that has deeper (or more) hidden layers of similar function cascaded into the network and has the capability to make meaning from medical big data. Current transformation drivers to achieve personalized health care delivery will be possible with the use of mobile health (mHealth). DL can provide the analysis for the deluge of data generated from mHealth apps. This paper reviews the fundamentals of DL methods and presents a general view of the trends in DL by capturing literature from PubMed and the Institute of Electrical and Electronics Engineers database publications that implement different variants of DL. We highlight the implementation of DL in health care, which we categorize into biological system, electronic health record, medical image, and physiological signals. In addition, we discuss some inherent challenges of DL affecting biomedical and health domain, as well as prospective research directions that focus on improving health management by promoting the application of physiological signals and modern internet technology.
Nature has been inspiring scientists to fabricate impact protective materials for applications in various aspects. However, it is still challenging to integrate flexible, stiffness-changeable, and ...protective properties into a single polymer, although these merits are of great interest in many burgeoning areas. Herein, we report an impact-protective supramolecular polymeric material (SPM) with unique impact-hardening and reversible stiffness-switching characteristics by mimicking sea cucumber dermis. The emergence of softness–stiffness switchability and subsequent protective properties relies on the dynamic aggregation of the nanoscale hard segments in soft transient polymeric networks modulated by quadruple H-bonding. As such, we demonstrate that our SPM could efficiently reduce the impact force and increase the buffer time of the impact. Importantly, we elucidate the underlying mechanism behind the impact hardening and energy dissipation in our SPM. Based on these findings, we fabricate impact- and puncture-resistant demos to show the potential of our SPM for protective applications.
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