摘要 : A water contact angle measurement method based on the improved Faster RCNN is proposed to address the issues of low accuracy and poor reproducibility caused by manual intervention in traditional water contact angle measurement processes. First, the Faster RCNN backbone network VGG16 was replaced with ResNet101, and the attention mechanism model convolutional block attention module (CBAM) was added at the end of its residual block to enhance the network's ability to extract features. Second, the feature pyramid network (FPN) was incorporated to fully extract feature information at different scales, and the Focal loss function was introduced to solve the problem of imbalanced positive and negative class samples. Finally, edge detection and corner extraction were performed on the located water droplets, and then the iterative reweighted least squares (IRLS) method was used to fit the elliptical contour to calculate the contact angle angle. The experimental results show that the improved Faster RCNN object detection algorithm improves mean average precision by 10.794% and speed by 11 frame/s over the original algorithm. The average standard deviation of contact angle angle measurements is 0.109°.

摘要 : The efficiency and stability of in situ remediation of Cr(VI) contamination in underground water and soil are still challenging. In this study, a green tea (GT) synthesized nano-zerovalent iron (nZVI) nanocomposite supported by diatomite (DE) (nZVI@GT/DE) via tea polyphenols was designed. The synergetic effect of DE support and tea polyphenols wrapping increased the Fe(II) component in nZVI@GT/DE and its transportability. Compared to nZVI@GT/Mont (supported by Mont with sandwich structure), nZVI@GT/DE exhibited a notably higher capacity (>100 mg g–1) for immobilizing Cr(VI) and a more pronounced ability to release iron ions in solution (corrosion parameter: K ≈ 1.046). This was attributed to the combined effect of the unwrapping process of tea polyphenols coverage and the distinctive columnar porous structure of DE, which increased the exposure of α-Fe0 core for enhanced Cr(VI) reduction during their cotransport in the water-saturated soil system. X-ray absorption fine structure and X-ray photoelectron spectroscopy analyses confirmed that nZVI@GT/DE released more Fe(II) ions to reduce Cr(VI) to bidentate binuclear Cr(OH)3 (vs FeOCr2O3) complexes. This study unraveled the molecular mechanism and highlighted the Cr speciation transformation and physiochemical property changes of nZVI@GT/DE during their cotransporting when applied in situ remediation in complex subsurface of Cr(VI)-contaminated groundwater and soil system.

摘要 : ObjectiveTo obtain novel and efficient thermally activated delayed fluorescence (TADF) materials, BPQPXZ and BPQTPA are synthesized using dibenzopyridoquinoxaline (BPQ) as acceptor (A) and triphenylamine (TPA) and phenoxazine (PXZ) as donors (D). The results show that the two materials have typical delayed fluorescence characteristics, a smaller energy gap (ΔEST) between singlet and triplet states, and a larger oscillator strength ( f ). The device based on BPQPXZ combined with a strong acceptor and a strong donor achieves deep-red emission with λEL at 660 nm. However, due to the influence of the energy-gap law, the external quantum efficiency (EQE) is only 1.0%. BPQTPA combined with a strong acceptor and a weak donor has a larger fluorescence quantum yield (82.7%) because of the weaker rigidity of TPA than that of PXZ. As a result, the donor and acceptor of BPQTPA have less distortion, more orbital overlap, and larger f . At the same time, the intramolecular charge transfer effect of BPQTPA is weakened, and the electron-donating ability of TPA is weaker than that of PXZ. BPQTPA exhibits a blue-shifted emission compared with BPQPXZ. Therefore, the device based on BPQTPA exhibits yellow emission with λEL at 555 nm. Compared with BPQPXZ, the turn-on voltage of BPQTPA is reduced to 2.8 V; the maximum current efficiency and power efficiency are increased by 32-fold and 36-fold, respectively, and the EQE is increased by 6-fold to 7.0%.MethodsIn this study, BPQPXZ and BPQTPA materials are synthesized using the Suzuki reaction and Buchwald-Hartwig reaction. The photophysical properties, electrochemical properties, thermal properties, and device performance of the two materials are investigated. Comparative analysis is conducted on the luminescent properties of two materials.Results and DiscussionsThe structures of two materials, BPQPXZ and BPQTPA, are verified by 1H nuclear magnetic resonance (1H NMR) spectroscopy and high-resolution mass spectrometry (HRMS). BPQPXZ exhibits deep-red emission with λPL at 655 nm, and BPQTPA exhibits yellow emission with λPL at 585 nm (Fig. 3). Compared with BPQPXZ, BPQTPA exhibits blue-shifted emission because of weaker electron-donating ability of TPA than PXZ. Similarly, the rigidity of TPA is weaker than that of PXZ, resulting in a greater degree of overlap between the HOMO and LUMO of BPQTPA, a higher oscillator strength, and a larger fluorescence quantum yield (82.7%) for BPQTPA, which is consistent with the density functional theory simulation results (Fig. 2). As shown in the transient PL decay spectra (Fig. 4), the delay component is observed, and such phenomena are typical behaviors of TADF. As shown in the cyclic voltammogram (Fig. 5), the HOMO levels of BPQTPA and BPQPXZ are -5.38 eV and -5.25 eV, respectively. The calculated LUMO levels are -3.00 eV and -3.27 eV for BPQTPA and BPQPXZ, respectively. BPQTPA shows better thermal stability with a higher decomposition temperature (Td, with 5% weight loss) of 492.6 °C than BPQPXZ (Td=439.2 °C). The higher thermal stability of BPQTPA can be ascribed to its better planarity than that of BPQPXZ. These devices based on BPQTPA and BPQPXZ achieve good performance (Fig. 7). The device based on BPQTPA exhibits much higher EQE (7.0%) than the device based on BPQPXZ (EQE is 1.0%), especially.ConclusionsIn this study, BPQTPA and BPQPXZ materials are designed and synthesized using BPQ with a highly rigid conjugated planar structure as an acceptor and TPA and PXZ as donors. The results show that two materials have typical delayed fluorescence characteristics. BPQTPA and BPQPXZ achieve good orbital separation between HOMO and LUMO, as well as a certain degree of orbital overlap, resulting in a smaller ΔEST and a larger oscillator strength. The device based on BPQPXZ combined with a strong acceptor and a strong donor achieves deep-red emission with λEL at 660 nm. However, due to the influence of energy-gap law, non-radiative decay is serious, with an EQE of only 1.0%, as well as low current and power efficiency. The device based on BPQTPA combined with a strong acceptor and a weak donor is less rigid than that based on BPQPXZ, making the degree of donor and acceptor distortion of BPQTPA less than BPQPXZ, and the degree of overlap between HOMO and LUMO orbitals of BPQTPA increases, so oscillator strength of BPQTPA is 2.2 times that of BPQPXZ. As a result, BPQTPA has a higher PLQY (82.7%). Meanwhile, due to the much weaker electron-donating ability of TPA than PXZ, the intramolecular charge transfer effect of BPQTPA is weakened, resulting in a significant blue-shift in both photoluminescence and electroluminescence peaks. The device based on BPQTPA exhibits yellow emission with λEL at 555 nm. Compared with BPQPXZ, the turn-on voltage of the device based on BPQTPA is reduced to 2.8 V, and the current efficiency and power efficiency are significantly improved by 32-fold and 36-fold, respectively. The EQE is increased by 6-fold to 7.0%. In particular, we investigate the effects of reasonable combinations of donor and acceptor on the photophysical and electroluminescent properties of materials through structure-activity relationships, and the study is of certain reference significance for the research on long-wavelength TADF materials.

摘要 : The fugitive emissions of greenhouse gases, primarily methane (CH4) and nitrous oxide (N2O), from water environments have aroused global concern. However, there are currently limited information about national-scale data of CH4 and N2O emissions from inland waters, such as lakes, rivers, and reservoirs, particularly in developing countries. This study employed machine learning techniques, based on the literature data and national water quality monitoring data, to reveal the CH4 and N2O emission patterns of China's inland waters at the third-level basin and daily resolution. Our results show significant seasonal variations in CH4 emissions, which were influenced by total nitrogen and chemical oxygen demand concentrations. Northern watersheds were identified as hotspots of CH4 emissions, with 57% higher CH4 flux than the other watersheds. In contrast, N2O had a relatively lower contribution to total carbon emissions and showed smaller temporal and spatial variations. The estimated total emissions of CH4 and N2O in China's inland waters in 2021 amounted to 80.22 Tg of carbon dioxide equivalent, accounting for 9–11% of China's terrestrial carbon sinks. This research provides valuable insights to guide the counting and control of greenhouse gas emissions from environmental water bodies.

摘要 : Visually induced motion sickness has become a serious problem for users of virtual reality technology. Users immersed in a virtual reality environment generally suffer from dizziness, vomiting, and other symptoms. The distortion in stereoscopic image acquisition leads to virtual space distortion in human perception, which may be an important factor inducing and enhancing visually induced motion sickness. To study the effect of the distortion of stereoscopic video acquisition on visually induced motion sickness, a virtual spatial distortion model is constructed based on the theory of stereoscopic video acquisition. In addition, different levels of stereoscopic spatially distorted videos are obtained from lenses with three focal length parameters. Visual perception experiments were conducted to objectively and subjectively evaluate visually induced motion sickness under different spatial aberrations. The results show that when the angle of view of the acquired stereoscopic video does not match the stereoscopic visual angle of human eyes, the distortion of the video significantly affects the visually induced motion sickness, and the distortion of the stereoscopic video acquisition results in a more intense visually induced motion sickness. This paper presents a novel and systematic method to experimentally verify that distortions in virtual space caused by the mismatch between acquisition and perception parameters enhance visually induced motion sickness. The findings of this study can help put forward practical mitigation methods.

摘要 : A tone mapping algorithm for high dynamic range (HDR) images based on the improved Laplacian pyramid is proposed to enhance the rendering effect of HDR images on ordinary displays. The algorithm decomposes the preprocessed image into high-frequency and low-frequency layers, which are then fed into two feature extraction sub-networks. The algorithm combines their output images having different features via a fine-tuning network and finally obtains a low dynamic range image with a superior perceptual effect. Furthermore, the algorithm designs an adaptive group convolution module to enhance the ability of the sub-network to extract local and global features. The test results show that, compared to the existing advanced algorithms, the proposed algorithm can compress the brightness of the HDR image better, retain more image details, and achieve superior objective quality and subjective perception.

摘要 : With the continuous integration of digital technology in daily life, the management path of colleges and universities also carries out development and optimization. The triple helix theory of education management model innovation in colleges and universities is the basis of this paper, which builds a model for education management innovation led by schools. An evaluation index system for college education management quality was constructed, taking into account the quality effect demand of education management. On this basis, combining the hierarchical method and cluster analysis method to calculate and classify the weights of the indicators of educational management in colleges and universities, and evaluating the quality of educational management in colleges and universities through the fuzzy comprehensive evaluation method to complete the construction of the indicator system of quality of educational management in colleges and universities. After examining the performance of the evaluation model and the rationality of the indexes, it is applied to the educational management examples to explore the sustainable development path of the educational management path in colleges and universities. The results show that the overall index coefficient is 0.875 and greater than 0.6, and the comprehensive evaluation score of the actual management quality of the triple helix educational management is 4.6826 points out of 5, which verifies the validity and reasonableness of this paper based on the triple helix educational management innovation model. The sustainable development of educational management is positively impacted by its scientific guidance on the innovative direction of university educational management models.

摘要 : This paper first explores the revitalization of national traditional sports and cultural innovation and identifies the key to the definition of national traditional sports. Secondly, it explores the operation mechanism of sports and cultural co-innovation and proposes pathways for sports and cultural innovation. Then, the relationship between traditional ethnic sports and sports culture innovation was studied using the BERT model in the deep learning model. Finally, a controlled experiment was designed to test the comparison of students' performance before and after learning about sports culture innovation, and the study showed that the performance was improved by 14.3506 and 13.6275, respectively, and that learning about sports culture innovation was effective in improving students' deep learning ability. Testing the role of three different algorithms on the revitalization and cultural innovation of national traditional sports, the accuracy of the four indicators of BERT is 0.75, 0.78, 0.88 and 0.98, respectively, which is in the first place, and the accuracy of BERT is higher.

摘要 : Organophosphorus flame retardants (OPFRs) are widely used in commercial products owing to their exceptional flame-retarding and plasticizing properties. However, OPFRs are also well recognized as emerging persistent organic pollutants (POPs) because of their environmental persistence, biological concentration, and potential toxicity. Thus, the accurate detection of OPFRs in environmental media is critical for analyzing their fate, transport, and ecological risk. However, very few OPFR detection methods are currently available, and the types of OPFRs detected may vary from site to site. In this study, matrix solid-phase dispersion extraction (MSPD), a simple, rapid, and versatile technique for preparing solid, semisolid, liquid, and viscous samples, was combined for the first time with gas chromatography-tandem mass spectrometry (GC-MS/MS) to analyze 10 OPFRs in soil, namely, tripropyl phosphate (TPrP), tri-n-butyl phosphate (TnBP), tri-iso-butyl phosphate (TiBP), tris(2-chloroisopropyl) phosphate (TCIPP), tris(2-chloroethyl) phosphate (TCEP), tris(1, 3-dichloro-2-propyl) phosphate (TDCPP), triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPP), triphenylphosphine oxide (TPPO), and trimethylphenyl phosphate (TCP). The GC-MS/MS system was equipped with a Bruker-5MS capillary column coupled with a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode. Prior to detection, a mixed standard solution was fortified with 10 ng of13C-PCB208 as an internal standard. The optimal conditions under which MSPD could achieve high selectivity for OPFRs were determined. In addition, single-factor analysis was used to examine the influence of the sorbent (i. e., C18, PSA, Florisil, GCB, and multiwalled carbon nanotubes (MWCNTs)) as well as the dosage, type, and volume of the eluent on the extraction efficiency of the method for the 10 OPFRs. When GCB and ethyl acetate were used as the adsorbent and solvent, respectively, during elution, high extraction recoveries for the OPFRs were achieved. Optimization via response surface methodology (RSM) was adopted to further analyze the impact of three key factors, namely, the adsorbent dosage, eluent volume, and grinding time, as well as their interactions, on OPFR recoveries. Under the optimal conditions of 0.3 g of GCB as the adsorbent, 10 mL of ethyl acetate as the eluent, and 5 min of grinding time, the relative average recovery of the OPFRs was 87.5%. Furthermore, the 10 OPFRs showed good linear relationships under five concentration gradients, with correlation coefficients greater than 0.998. The limits of detection (LODs) and quantification (LOQs) were calculated as signal-to-noise ratios (S/N) of 3 and 10, respectively, and found to be in the ranges of 0.006-0.161 and 0.020-0.531 ng/g, respectively. The performance of the proposed method was verified by determining the recoveries and relative standard deviations (RSDs) of the OPFRs in soils spiked at low, medium, and high levels (10, 20, and 100 ng/g, respectively). The recoveries of the OPFRs ranged from 70.4% to 115.4%, with RSDs ranging from 0.7% to 6.7%. Compared with the conventional accelerated solvent extraction (ASE) method, MSPD presents higher efficiency, simpler operation, and less solvent requirements. The developed method was applied to determine OPFRs in soil samples collected from different sites in Suzhou, including an electronics factory, an auto-repair factory, a paddy field, and a school field. The results revealed that the contents of OPFRs in the soils from the electronics and auto-repair factories were significantly higher than those in the soils from the paddy and school fields. The main pollutants in the soil samples collected from the electronics and auto-repair factories were TCIPP, TPPO, TCEP, and TDCPP. Moreover, the contents of these compounds were 5.30, 4.44, 4.54, and 4.20 ng/g, in soils from the electronics factory and 2.70, 3.93, 7.60, and 5.04 ng/g, in soils from the auto-repair factory. To the best of our knowledge, this study is the first to determine high concentrations of TPPO in industrial soils. Thus, the combination of MSPD and GC-MS/MS adopted in this study can provide useful insights into the detection of the 10 OPFRs in soil.

摘要 : With the rapid development of the data and information age, the digital-driven library has become an inevitable trend of library development. In this paper, through the Apriori association rule algorithm, the digital-driven library model for the influence factors of information mining, combined with data mining influence factor information to build a data-driven library management system, through the data library lending system optimization and book scheduling optimization to optimize and improve the overall optimization. Finally, it is verified through empirical analysis of association rule analysis and the scheduling effects of data-driven libraries. Through empirical analysis, it can be seen that the staff management efficiency of the management system lending system, and library circulation scheduling enhancement degree are 5.103 and 6.103, both greater than 1. The length of the reader queue and the percentage of reader loss of the data-driven library are between 5~15 and 0%~17%, respectively, and the efficiency of the data-driven library is superior to that of traditional libraries. Combined with the above, this paper based on the data-driven university library management service model can effectively solve the book scheduling problem, improve the management and service efficiency, so that readers have a better experience, and provide a guarantee for the innovative development path of the data-driven library management service model.