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Brillouin spectroscopy is a powerful tool to measure the water temperature and salinity profiles of seawater. Considering the insufficiency of the current spectral measurement methods in real-time, spectral integrity, continuity, and stability, we developed a new lidar system for spectrum measurement on an airborne platform that is based on a Fizeau interferometer and multichannel photomultiplier tube. In this approach, the lidar system uses time-of-flight information to measure the depth and relies on Brillouin spectroscopy as the temperature and salinity indicator. In this study, the system parameters were first optimized and analyzed. Based on the analysis results, the performance of the system in terms of detection depth and accuracy was evaluated. The results showed that this method has strong anti-interference ability, and under a temperature measurement accuracy of 0.5 °C and a salinity measurement accuracy of 1‰, the effective detection depth exceeds 40.51 m. Therefore, the proposed method performs well and will be a good choice for achieving Brillouin lidar application in seawater remote sensing.

Photocatalysts are usually in powder form, which makes it difficult to expand the scale of photocatalysis. Here, we report a Newtonian fluid photocatalyst, which consists of an internal nano-hollow imidazole framework and an external light-excitable liquid chain striking a pose on the stage. Due to the intermolecular interaction at the solid-liquid interface and significant steric hindrance effect, the Newtonian fluid catalyst with higher surface tension can firmly adhere to different kinds of scaffolds via simple printing, such as curved surfaces, inclined walls, and grids. In addition to the easier scale-up, the pore structure of frameworks favors faster CO 2 mass transfer, and the liquid chain with a co-catalytic effect serves as the electron donor for efficient CO 2 photoreduction. In this work, the Newtonian fluid photocatalyst achieves a 57.8-fold increase in CO overflow efficiency (100% selectivity), and this universal synthesis method can convert common organic/inorganic photocatalysts into similar Newtonian fluid photocatalysts. The Newtonian fluid photocatalyst composed of imidazole framework and light-excitable liquid chain can be firmly attached to different types of carriers through printing for easier photocatalytic scaling up and more stable CO 2 photoreduction.

Spaceborne photon-counting LiDAR holds significant potential for shallow-water bathymetry. However, the received photon data often contain substantial noise, complicating the extraction of elevation information. Currently, a denoising algorithm named ordering points to identify the clustering structure (OPTICS) draws people’s attention because of its strong performance under high background noise. However, this algorithm’s fixed input variables can lead to inaccurate photon distribution parameters in areas near the water bottom, which results in inadequate denoising in these areas, affecting bathymetric accuracy. To address this issue, an Adaptive Variable OPTICS (AV-OPTICS) model is proposed in this paper. Unlike the traditional OPTICS model with fixed input variables, the proposed model dynamically adjusts input variables based on point cloud distribution. This adjustment ensures accurate measurement of photon distribution parameters near the water bottom, thereby enhancing denoising effects in these areas and improving bathymetric accuracy. The findings indicate that, compared to traditional OPTICS methods, AV-OPTICS achieves higher F1-values and lower cohesions, demonstrating better denoising performance near the water bottom. Furthermore, this method achieves an average MAE of 0.28 m and RMSE of 0.31 m, indicating better bathymetric accuracy than traditional OPTICS methods. This study provides a promising solution for shallow-water bathymetry based on photon-counting LiDAR data.

This article presents a LiDAR system that utilizes a Fizeau interferometer and photomultiplier tube array to detect the water Rayleigh–Brillouin spectrum, utilized to obtain underwater temperature and salinity synchronizing measurements based on the Brillouin spectral linewidth and shift. Temperature and salinity measurements were conducted in the laboratory to verify the efficiency of the system. The results demonstrate that the LiDAR system can accurately obtain the Rayleigh–Brillouin spectral backscattering profiles of water. Following linear fitting and reconstruction, the retrieved temperature accuracy is ±0.13 °C and salinity accuracy is ±0.16‰. By effectively leveraging the multiparameter information contained in the Rayleigh–Brillouin spectrum, the system achieved precise temperature and salinity measurements. This study provides a reference for marine remote sensing applications

The doping of multilayer graphene (MLG) was investigated in this study to optimize the mechanical properties, elastocaloric effect and cyclic stability of Ni-Co-Mn-Ti alloys. The formation energies of Ni 6 Co 2 Mn 6 Ti 2 and Ni 6 Co 2 Mn 6 Ti 2 C 1 alloys were calculated using first-principles methods. It was revealed that the introduction of C(MLG) significantly reduced the formation energy, thereby enhancing the stability of the crystal structure. The microstructure, martensitic transformation, crystal structure, mechanical properties, elastocaloric performance and cyclic stability of MLG x /(Ni 36 Co 14 Mn 35 Ti 15 ) 100- x ( x  = 0, 0.3, 0.6, 0.9, 1.5) alloys were systematically investigated. It was found that the doping of MLG induced the formation of black particulate precipitates within the alloy. These precipitates altered the composition of the alloy matrix and led to an increase in the phase transformation temperature. The incorporation of MLG further facilitated the transition of the alloy's crystal structure from an L2₁ cubic austenite phase to a 10 M martensitic phase. Moreover, both the mechanical strength and the elastocaloric properties were significantly enhanced by MLG doping. The compressive fracture stress and strain were observed to increase progressively with increasing MLG content. Specifically, the MLG 1.5 /(Ni 36 Co 14 Mn 35 Ti 15 ) 98.5 alloy achieved a compressive fracture stress of 1005 MPa and a compressive fracture strain of 10.3% at 293 K. Furthermore, the alloy with 0.6 at.% MLG achieved a ΔT ad of -4.32 K under a compressive stress of 400 MPa and demonstrated superior cyclic stability with 800 cycles under a stress of 300 MPa.

This study systematically investigates the microstructure, martensitic phase transformation, crystal structure, and mechanical properties of (Ni 43 Mn 47 Sn 9 Gd 1 ) 100−x B x (x = 0, 0.8, 1.5 and 3 at%) shape memory alloys. Experimental results reveal that these alloys consist of a matrix phase and precipitated phases. The introduction of Gd elements leads to the formation of milky-white particles dispersed along grain boundaries, with the composition identified as GdNiSn. When the B element content reaches 1.5 at%, bright-white particles form and are uniformly distributed within the matrix. Their concentration increases with higher levels of B doping, and they are characterized as Mn 2 B. Simultaneously, the initially present Gd-rich milky-white particles distributed along grain boundaries, exhibit a diminishing trend with increasing B doping. B doping elevates the alloy’s phase transition temperature, and the compressive strength of the alloy approximately follows a linear trend with increasing B content. At a B doping level of 3%, the annealed alloy demonstrates a compressive strength of up to 1313 MPa with a compressive fracture strain of 11.6%, marking a 110% improvement. For the as-cast alloy, a compressive strength of 1652 MPa is achieved, accompanied by a compressive fracture strain of 12.3%, representing a 130% enhancement. Transmission electron microscopy reveals pronounced twinning features on the alloy surface, resulting in the formation of numerous fine lines in the as-cast state, that are magnified into voids after heat treatment. This phenomenon is detrimental to the alloy’s mechanical performance; hence, the as-cast compressive strength is favored over the annealed state.

Improvement of selectivity and activity of imprinted photocatalysis is a major challenge for antibiotic photodegradation due to the functional monomers of imprinting hindering the photogenerated carrier migration. Here, an organic imprinted Ag-polyaniline/CoFe2O4/Carbon photocatalyst (IM-Ag-PANI/CoFe2O4/C) was successfully prepared by photo-initiated polymerization which achieved selective photodegradation of tetracycline (TC). The heterojunction formed by the functional monomer Ag@PANI and CoFe2O4/C not only facilitates the separation of photo-excited carriers and the exposure of active sites but also contributes to the selective adsorption capability by imprinted cavity on Ag@PANI, thereby improving the photocatalytic activity and selectivity simultaneously. In addition, the Corncob conversion carbon matrix method and iron-based magnetic character enable a more environmentally friendly and recyclable capability of IM-Ag-PANI/CoFe2O4/C. After using machine learning models to train and predict experimental parameters by changing experimental parameters, the IM-Ag-PANI/CoFe2O4/C can photodegrade 82.23% of TC within 2 h, and it has a selective degradation ability compared to enrofloxacin hydrochloride (EH). This research provides a new idea for the construction of imprinted photocatalytic materials that can improve photocatalytic activity.

In this study, the hydrothermal in situ growth technique was used to controllably produce the stable nanoflower-like Pt-MoS2/BiVO4 (Pt-MS/BVO) composite. MoS2 nanospheres were embellished with BiVO4 and Pt nanoparticles. Excellent photocatalytic efficiency for the TC degradation was demonstrated by the Pt-MS/BVO composite. In the light irradiation, degradation efficiency was 11 and 5 times higher than MoS2 and BiVO4, respectively. The reaction speed of Pt-MS/BVO was 1.9, 3.2, and 18.3 times that of MoS2/BiVO4 (MS/BVO), BiVO4, and MoS2, according to the photocatalytic kinetics fitting curve. MoS2 not only resulted in good dispersion of Pt and BiVO4, furthermore but also performed a significant part in the creation of direct Z-type charge-transfer composites with relatively short charge diffusion distances and abundant intimate contact interfaces, while the noble metal Pt acted as an electron collector to suppress the electron–hole complexation rate, thus improving the photocatalytic activity. This study sheds light on the ternary photocatalyst’s rational design for multilayer electron transport and achieves efficient removal of tetracycline residues in the water environment.

Selective photodecomposition of highly toxic pollutants is a significant challenge because the free radicals produced by photocatalyst show an indistinguishable attack on all contaminants in wastewater. To realize selective photodegradation, an organic imprinted Ag-PANI/CdS/Fe3O4/Biochar photocatalyst (IM-Ag-PANI/CdS/Fe3O4/BC) was successfully prepared by photoinitiated polymerization method. The formation of heterojunction facilitates the separation of photoexcited carriers and effectively inhibits the photocorrosion of CdS, thereby improving the photocatalytic activity and stability of photocatalysts. Moreover, the imprinted cavities in Ag-PANI layer help to selectively adsorb and degrade 2-mercapto-1-methylimidazole (MMIZ), resulting in a high selectivity coefficient of 2.40 relative to 5-Mercapto-1-methyltetrazole, and the photodegradation efficiency of MMIZ is boosted up to 76% within 1 h. This work provides a new idea to construct stable photocatalysts with high selectivity for the decontamination of target pollutants.