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•Fe nanoparticles (Fe NPs) were synthesized by tea extracts.•Fe NPs as the catalyst were used for Fenton-like oxidation of monochlorobenzene.•The oxidation of MCB and the removal of ...COD were 81.15% and 31.01%, respectively.•The mechanism for Fenton-like oxidative mechanism was proposed.
Iron nanoparticles (Fe NPs) were synthesized using tea extracts as a catalyst for the Fenton-like oxidation of monochlorobenzene (MCB), where 69%, 53%, and 39% of MCB were, respectively, degraded by Fe NPs synthesized using green tea extracts, oolong tea extracts, and black tea extracts. Fe NPs synthesized using green tea extracts (GT-Fe NPs) demonstrated the best degradation since green tea contains a high concentration of caffeine/polyphenols used as both reducing and capping agents in the synthesis of Fe NPs. This was confirmed by SEM image, EDS, and XRD pattern of GT-Fe NPs. In addition, batch experiments show that the oxidation of MCB and the removal of chemical oxygen demand (COD) using GT-Fe NPs were 81% and 31%, respectively, at optimal conditions, where dosages were 0.6g/L GT-Fe NPs, 0.045mol/L H2O2, and initial pH of 3.0. Compared to homogeneous Fenton oxidation of MCB, GT-Fe NPs as a heterogeneous catalyst indicate that Fe2+ and Fe3+ leached from GT-Fe NPs nanoparticles and consequently reduced the formation of iron sludge. Finally, GT-Fe NPs were successful in removing MCB from wastewaters, and the possible Fenton-like oxidative mechanism of MCB was proposed. The proposition was based on adsorption of MCB on the surface of GT-Fe NPs, decomposition of H2O2, generation of hydroxyl radicals, and oxidation of MCB.
This study used visible/near-infrared hyperspectral imaging (HSI) technology combined with chemometric methods to assess the freshness of pearl gentian grouper. The partial least square ...discrimination analysis (PLS-DA) and competitive adaptive reweighted sampling-PLS-DA (CARS-PLS-DA) models were used to classify fresh, refrigerated, and frozen-thawed fish. The PLS-DA model achieved better classification of fresh, refrigerated, and frozen-thawed fish with the accuracy of 100%, 96.43%, and 96.43%, respectively. Further, the PLS regression (PLSR) and CARS-PLS regression (CARS-PLSR) models were used to predict the storage time of fish under different storage conditions, and the prediction accuracy was assessed using the prediction correlation coefficients (R
), root mean squared error of prediction (RMSEP), and residual predictive deviation (RPD). For the prediction of storage time, the CARS-PLS model presented the better result of room temperature (R
= 0.948, RMSEP = 0.255, RPD = 4.380) and refrigeration (R
= 0.9319, RMSEP = 1.188, RPD = 3.857), while the better prediction of freeze was by obtained by the PLSR model (R
= 0.9250, RMSEP = 2.910, RPD = 3.469). Finally, the visualization of storage time based on the PLSR model under different storage conditions were realized. This study confirmed the potential of HSI as a rapid and non-invasive technique to identify fish freshness.
An ultra‐wideband and wide‐scan tightly coupled dipoles array based on frequency selective surface (FSS) is proposed, and the traditional wide‐angle scan impedance matching dielectric layer is ...replaced by FSS with printed metal strips to achieve the tuning of the scanning impedance of the array. Additionally, the metal strip FSS, dipole radiating elements and feeding structure are all printed on the same printed circuit board, and the whole design is highly integrated. Finally, a low‐cost lightweight single‐polarization tightly coupled antenna array with ultra‐wide band and wide scan performance is presented. Subject to the criterion of active Voltage standing Wave ratio(VSWR) < 3, beam scanning coverage of ±45° along E plane, H plane and D plane can be accomplished within the frequency band range across 0.4–2 GHz. An array prototype was produced and tested, and the results showed that the effectiveness of the design was well validated.
This paper presents a low profile ultra‐wideband wide scan tightly coupled dipole array. Based on frequency selective surface and integrated balun, this array works within frequency band range across 0.4–2 GHz. The test indicated that the design is well validated.
Oxidative stress and excessive nitric oxide (NO) production play considerable roles in infarction-induced injury impairing cardiac functions. Crocin is the active constituent of Crocus sativus ...(saffron) with antioxidant properties and has protective effects against disturbances induced by ischemia in many organs. The present study aimed to investigate the protective effects and the underlying mechanisms of crocin on myocardial infarction (MI)-induced injury in rats in vivo. MI rats were intraperitoneally injected with crocin at different doses for seven successive days after coronary ligation. Infarct size, hemodynamic studies, and capillary density were evaluated. Levels of oxidative stress, inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and their corresponding phosphorylation expressions were then measured. Crocin decreased infarct size, left ventricular (LV) end-diastolic pressure, and LV minimum dP/dt while increased LV maximum dP/dt and percentage of LV fractional shortening dose dependently. Capillary density was markedly increased after crocin treatment. Crocin enhanced superoxide dismutase activity and reduced malondialdehyde levels as well as inhibited excessive production of NO through downregulating iNOS as well as upregulating eNOS during MI-induced injury. This study reveals that crocin improves MI-induced impairments in cardiac function, which is associated with its antioxidant properties.
Inshore ship detection is an important research direction of synthetic aperture radar (SAR) images. Due to the effects of speckle noise, land clutters and low signal-to-noise ratio, it is still ...challenging to achieve effective detection of inshore ships. To solve these issues, an inshore ship detection method based on the level set method and visual saliency is proposed in this paper. First, the image is fast initialized through down-sampling. Second, saliency map is calculated by improved local contrast measure (ILCM). Third, an improved level set method based on saliency map is proposed. The saliency map has a higher signal-to-noise ratio and the local level set method can effectively segment images with intensity inhomogeneity. In this way, the improved level set method has a better segmentation result. Then, candidate targets are obtained after the adaptive threshold. Finally, discrimination is employed to get the final result of ship targets. The experiments on a number of SAR images demonstrate that the proposed method can detect ship targets with reasonable accuracy and integrity.
Network-group targets are a set of objectives that adhere to a shared communication protocol, perform common tasks, and exhibit relatively coordinated movements. Typically, network-group targets emit ...radar and communication signals. However, they often employ a silent mode to evade our perception. Despite this, they continue to exchange data through their communication networks. By intercepting the communication signals of these targets, this paper proposes a method for estimating the state and network topology of network-group targets based on random finite set (RFS) theory. This method is based on the modeling of network-group targets using a labeled multi-Bernoulli (LMB) RFS. In state estimation, the usual method involves extracting the localization parameters from the signals in the first step and use these parameters for target tracking in the second step. This study focused on estimating the kinematic states of network-group targets using communication signals containing delay and Doppler information received by multiple mobile sensor platforms. The proposed method considers the coherency between frequency-hopping pulses in the signals, resulting in an improved estimation performance. In addition, considering that network-group targets require network access for information exchange, graph theory concepts were utilized to estimate the network topology of network-group targets by address measurement. The simulation results validated the effectiveness of the proposed method and demonstrated its superior performance.
Moderate leaf rolling helps to form the ideotype of rice. In this study, six independent OsRUS1-GFP overexpression (OsRUS1-OX) transgenic rice lines with rapid and dynamic leaf rolling phenotype in ...response to sunlight were constructed. However, the mechanism is unknown. Here, RNA-Seq approach was utilized to identify differentially expressed genes between flag leaves of OsRUS1-OX and wildtype under sunlight. 2920 genes were differentially expressed between OsRUS1-OX and WT, of which 1660 upregulated and 1260 downregulated. Six of the 16 genes in GO: 0009415 (response to water stimulus) were significantly upregulated in OsRUS1-OX. The differentially expressed genes between WT and OsRUS1-OX were assigned to 110 KEGG pathways. 42 of the 222 genes in KEGG pathway dosa04075 (Plant hormone signal transduction) were differentially expressed between WT and OsRUS1-OX. The identified genes in GO:0009415 and KEGG pathway dosa04075 were good candidates to explain the leaf rolling phenotype of OsRUS1-OX. The expression patterns of the 15 genes identified by RNA-Seq were verified by qRT-PCR. Based on transcriptomic and qRT-PCR analysis, a mechanism for the leaf rolling phenotype of OsRUS1-OX was proposed. The differential expression profiles between WT and OsRUS1-OX established by this study provide important insights into the molecular mechanism behind the leaf rolling phenotype of OsRUS1-OX.
Superpixel methods are widely used in the processing of synthetic aperture radar (SAR) images. In recent years, a number of superpixel algorithms for SAR images have been proposed, and have achieved ...acceptable results despite the inherent speckle noise of SAR images. However, it is still difficult for existing algorithms to obtain satisfactory results in the inhomogeneous edge and texture areas. To overcome those problems, we propose a superpixel generating method based on pixel saliency difference and spatial distance for SAR images in this article. Firstly, a saliency map is calculated based on the Gaussian kernel function weighted local contrast measure, which can not only effectively suppress the speckle noise, but also enhance the fuzzy edges and regions with intensity inhomogeneity. Secondly, superpixels are generated by the local
-means clustering method based on the proposed distance measure, which can efficiently sort pixels to different clusters. In this step, the distance measure is calculated by combining the saliency difference and spatial distance with a proposed adaptive local compactness parameter. Thirdly, post-processing is utilized to clean up small segments. The evaluation experiments on the simulated SAR image demonstrate that our proposed method dramatically outperforms four state-of-the-art methods in terms of boundary recall, under-segmentation error, and achievable segmentation accuracy under almost all of the experimental parameters at a moderate segment speed. The experiments on real-world SAR images of different sceneries validate the superiority of our method. The superpixel results of the proposed method adhere well to the contour of targets, and correctly reflect the boundaries of texture details for the inhomogeneous regions.
In this paper, the influence of calcium on coal gangue and fly ash geopolymer is explored, and the problem of low utilization of unburned coal gangue is analyzed and solved. The experiment took ...uncalcined coal gangue and fly ash as raw materials, and a regression model was developed with the response surface methodology. The independent variables were the CG content, alkali activator concentration, and Ca(OH)
to NaOH ratio (CH/SH). The response target value was the coal gangue and fly-ash geopolymer compressive strength. The compressive strength tests and the regression model obtained by the response surface methodology showed that the coal gangue and fly ash geopolymer prepared with the content of uncalcined coal gangue is 30%, alkali activator content of 15%, and the value of CH/SH is 1.727 had a dense structure and better performance. The microscopic results demonstrated that the uncalcined coal gangue structure is destroyed under an alkali activator's action, and a dense microstructure is formed based on C(N)-A-S-H and C-S-H gel, which provides a reasonable basis for the preparation of geopolymers from the uncalcined coal gangue.
Coal gangue and aluminum ash emerge as quintessential constituents within the ambit of coal-derived solid waste and industrial residue, respectively. Leveraging coal gangue as a primary substrate and ...aluminum ash as an adjunct aluminum source, molecular sieves can be synthesized through hydrothermal means. By modulating the dosage of aluminum ash, molecular sieves with varying crystalline structures can be obtained. The synthesized LTA-type molecular sieves manifest in two distinct morphologies: regular tetrahedral and stratified spherical stacking, evincing commendable Cu2+ adsorption efficacy. The Cu2+ adsorption phenomenon predominantly transpires via chemisorption, albeit with ancillary manifestations of physical adsorption. The valorization of coal gangue and aluminum ash towards the synthesis of molecular sieves not only underscores the elevation of industrial solid waste towards high-value utility, but also underscores the praxis of waste remediation through upcycling.
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