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Efforts to increase the number of filters are driven by the demand for miniaturized spectrometers and multispectral imaging. However, processes that rely on sequential fabrication of each filter are cost ineffective. Herein, we introduce an approach to produce at least 16 distinct filters based on a single low-resolution lithographic step with minimum feature size of 0.6 μm. Distinct from grayscale lithography, we employ standard binary lithography but achieve height variations in polymeric resist through a post-development reflow process. The resulting transparent polymeric films were incorporated in Fabry–Perot cavity structures with cavity thickness ranging from 90 to 230 nm to produce transmittance across the visible spectrum. This binary lithography and reflow (BLR) process demonstrates control of the dielectric layer thickness down to ∼15 nm. This new process provides a cost-effective alternative to traditional techniques in fabricating microscopic transmission filters, and other applications where precise thickness variation across the substrate is required.

[Objective] As a new type of economic form characterized by innovation, progress, and extension, digital economy is an important driving force to promote the high-quality development of the Yellow River Basin and create new advantages in regional competition. Exploring the evolution of the spatial pattern of digital economy enterprises in the Yellow River Basin and the influencing factors is of great significance for realizing the effect of digital economy reshaping the economic geographical pattern. [Methods] Based on the data of more than 130000 digital economy enterprises in the Yellow River Basin from 2002 to 2019, we used standard deviation ellipse, kernel density estimation, and the multi-scale geographically weighted regression model to explore the evolution of the spatial pattern of digital enterprises in the region. [Results] (1) The number of digital economy enterprises in the Yellow River Basin had increased significantly, showing the characteristics of downstream cities > midstream cities > upstream cities, with the overall spatial pattern of strong in the east and weak in the west and a trend of contraction, and the urban agglomerations showed significant differences in the development process. (2) The distribution of the digital industry manufacturing enterprises showed a trend of a single cluster of downstream cities and the orderly expansion of middle and upstream cities, while the digital technology application enterprises showed a trend of close connection between middle and downstream cities and multi-core clusters. (3) The location selection of digital industry manufacturing enterprises gives more consideration to location factors and has the characteristics of path dependence, while the location selection of digital technology application enterprises gives consideration to location and technology factors and has the characteristics of both path dependence and path creation. [Conclusion] Developing digital economy according to local conditions is an important means to achieve high-quality development of the Yellow River Basin, and we recommend to promote the digital economy industry to release its potential by improving its foundation, achieving precise layout, promoting innovation and optimizing the structure, and promoting innovation.

When a fire occurs in an underground shield tunnel, it can result in substantial property damage and cause permanent harm to the tunnel lining structure. This is especially true for large-diameter shield tunnels that have numerous segments and joints, and are exposed to specific fire conditions in certain areas. This paper constructs a full-scale shield tunnel fire test platform and conducts a non-uniform fire test using the lining system of a three-ring large-diameter shield tunnel with an inner diameter of 10.5 m. Based on the tests, the temperature field distribution, high-temperature bursting, cracking phenomena, and deformation under fire conditions are observed. Furthermore, the post-fire damage forms of tunnel lining structures are obtained through the post-fire ultimate loading test, and the corresponding mechanism is explained. The test results illustrate that the radial and circumferential distribution of internal temperature within the tunnel lining, as well as the radial temperature gradient distribution on the inner surface of the lining, have non-uniform distribution characteristics. As a result, the macroscopic phenomena of lining concrete bursting and crack development during the fire test mainly occur near the fire source, where the temperature rise gradient is the highest. In addition, the lining structure has a deformation characteristic of local outward expansion and cannot recover after the fire load is removed. The ultimate form of damage after the fire is dominated by crush damage from the inside out of the lining joints in the fire-exposed area. The above results serve as a foundation for future tunnel fire safety design and evaluation.

Lysozyme, a common antimicrobial agent, is widely used in the food, biopharmaceutical, chemical, and medicine fields. Rapid and effective isolation of lysozymes is an everlasting topic. In this work, ethylene vinyl alcohol (EVOH) copolymer nanofibrous membranes with a gradient porous structure used for lysozyme adsorption were prepared through layer-by-layer nanofiber wet-laying and a cost-efficient ultraviolet (UV)-assisted graft-modification method, where benzophenone was used as an initiator and 2-acrylamide-2-methylpropanesulfonic acid as a modifying monomer. As indicated in the Fourier Transform Infrared (FTIR) and X-ray photoelectric energy spectrometer (XPS) investigation, sulfonic acid groups were introduced on the surface of the modified nanofibrous membrane, which possessed the ability to adsorb lysozyme. Compared with membranes with homogenous porous structures, membranes with a gradient porous structure present higher static (335 mg/g) and dynamic adsorption capacities (216.3 mg/g). Meanwhile, the adsorption capacity remained high after five cycles of the adsorption–desorption process. The results can be attributed to the gradient porous structure rather than the highest porosity and specific surface area. This suggests that the membrane with comprehensive separation performance can be designed from the view of the transmembrane porous structure, which is of significance for the development of next-generation advanced chromatographic membranes.

The study on the return period of extreme precipitation can improve the understanding of precipitation regularity, which is of great significance for preventing urban waterlogging, farmland waterlogging. To study the characteristics of the probability distribution of extreme precipitation in Liaoning Province, we use the daily precipitation data from 14 national meteorological observational stations in Liaoning Province during May to October of 1960-2020, and select the 98th percentile as the threshold of extreme precipitation. The Poisson-generalized Pareto compound extreme value model fits the extreme precipitation days and extreme precipitation amount and estimates the precipitation amount during the return period in Liaoning Province. The results show that the days with extreme precipitation and the extreme precipitation amount in Liaoning Province follow the Poisson distribution and the generalized Pareto distribution, respectively (both passed the statistically significant test of α=0.05). Extreme precipitation shows a gradual increase from the northwest to the southeast in Liaoning Province. The amount of extreme precipitation and the days of extreme precipitation are highest in the Dandong city. The Poisson-generalized Pareto compound extreme value model and the empirical frequency method can fit the precipitation amount during the return period very well. Under different return periods, the extreme precipitation amount in southeastern Liaoning Province is the highest.The extreme precipitation amount is relatively small in the middle of Liaohe River Basin, and is the smallest in the Northwest. The extreme precipitation amount in the mountainous areas of eastern Liaoning and the hilly areas of western Liaoning is higher than that in the plains of central Liaoning, and this spatial distribution is consistent for different return periods.

The purpose of crowd counting is to accurately predict the number, distribution and density of crowds in real scenes. However, crowd counting often suffers from some problems such as complex background, diverse target scales, and cluttered crowd distribution, which strongly affects the precision of counting. To solve these problems, a channel and spatial attention-based encoder-decoder network for crowd counting (CSANet) is proposed. It uses a multi-level encoder-decoder network to extract multi-scale semantic features, and fully integrates spatial context information to solve the problem of pedestrian scale changes and messy distribution in complex scenes. To reduce the impact of complex background on counting performance, channel and spatial attention are introduced in the process of feature fusion to improve the quality of crowd density map by increasing the feature weights of crowd regions to highlight regions of interest, and decreasing the feature weights of weakly correlated background regions to suppress background noise interference. To verify the effectiveness of the proposed algorithm, experiments are conducted on several classical crowd counting datasets, and the experimental results show that CSANet performs well in multi-scale feature extraction and background noise suppression compared with existing crowd counting algorithms, which greatly improves the accuracy and robustness of counting algorithm in dense scenes.

Cellulose acetate oleate (CAO)-reinforced poly(butylene adipate-co-terephthalate) (PBAT) composites were prepared by the solvent casting method. The influence of the addition of CAO on the mechanical property, thermal property, disintegration property, compatibility, and hydrophobicity of PBAT/CAO composites was investigated. Compared with PBAT, the tensile strength and Young’s modulus of PBAT/CAO with 4 wt% CAO were increased by 9.5% and 25.7%, and the disintegration rate was also increased by 2.8 times. The results of morphological property, contact angle, and water vapor transmission indicated that the PBAT/CAO composites had good interfacial interaction and compatibility, and the hydrophobicity was improved. PBAT/CAO was applied to strawberry preservation, and it showed excellent freshness retention performance. Moreover, a possible degradation pathway for PBAT/CAO composite was proposed. This work provided a way for the preparation and performance improvement of biodegradable materials, which is expected to be applied in the packaging field.