In order to understand the effects of nitrogen ionization during preparation and oxygen pressure during annealing (OPA) on the morphology, structure, and luminescent properties of Mg-doped ZnO thin ...films, Zn
0.97
Mg
0.03
O films were prepared in both ionized and non-ionized N
2
using Pulsed Laser Deposition (PLD), followed by annealing at 600 °C under various oxygen pressures. X-ray Diffraction (XRD) results reveal that all Zn
0.97
Mg
0.03
O films exhibit a preferentially oriented hexagonal wurtzite structure along the (002) direction, with the films prepared in ionized nitrogen showing the presence of Zn
3
N
2
phase. Field Emission Scanning Electron Microscopy (FESEM) observations indicate that the films prepared in non-ionized and ionized N
2
exhibit near-spherical and conical shaped particles, respectively. Combined XRD and X-ray Photoelectron Spectroscopy (XPS) analyses indicate an increase in Zn interstitial (Zn
i
) content in the films after annealing, with higher content observed at a higher OPA; films annealed under oxygen pressure of 100 Pa exhibit maximum tensile stress and highest N content. Photoluminescence (PL) spectra of both ionized and non-ionized films reveal a strong ultraviolet-violet peak (360–450 nm) and weaker blue-green peak (450–550 nm), with a broad and weak near-infrared (NIR) peak around 825 nm. The NIR peak primarily originates from the recombination of electrons bound to Zn
i
and holes bound to oxygen vacancies (Vo) ; ionization of nitrogen enhances the green emission.
Circular RNA (circRNA) MFACR promotes cardiomyocyte death that leads to myocardial infarction (MI). This study aimed to explore the role of MFACR in MI. T-qPCRs were performed to measure the ...expression levels of MFACR and miR-125b in plasma samples from both MI patients (n = 61) and healthy controls (n = 61). MFACR or miR-125b was overexpressed in AC16 cells (cardiomyocytes) to explore the interaction between them. Methylation of miR-125b gene in cells with the overexpression of MFACR was detected by methylation-specific PCR. Cell apoptosis after transfections was detected by cell apoptosis assay. MI model was constructed to further demonstrate the effect of MFACR in vivo. We found that MFACR was upregulated in MI and inversely correlated with miR-125b. In AC16 cells, hypoxia treatment increased the expression levels of MFACR and decreased the expression levels of miR-125b. In AC16 cells, overexpression of MFACR decreased the expression levels of miR-125b and increased the methylation of miR-125b gene. Under hypoxia treatment, overexpression of MFACR increased AC16 cell apoptosis, and overexpression of miR-125b decreased cell apoptosis. In addition, overexpression of miR-125b reversed the effects of overexpression of MFACR on cell apoptosis both in vivo and in vitro.
The application of porous carbon microspheres derived from pure biomass in supercapacitors is restricted due to their limited reactive groups. MXene owns a combination of redox Faradic surface with ...good metallic conductivity and hydrophilicity, which assists to obtain high pseudocapacitance and energy density. Herein, Ti3C2Tx MXene was introduced to chitosan-based porous carbon microsphere (CPCM) to fabricated sandwich-like structure (CPCM/MXene) through electrostatic interaction. The Ti3C2Tx protected the spherical structure of CPCM. Meanwhile, CPCM hindered the reaggregation of Ti3C2Tx by inserting in the Ti3C2Tx layers, promoting the electrolyte migration kinetics. The synergistic effect endowed CPCM/MXene high specific capacitance of 362 F/g at current density of 0.5 A/g and acceptable cycling stability with 93.87% capacitance retention at a high current density of 10 A/g after 10,000 cycles. Furthermore, CPCM/MXene displayed a high energy density of 27.8 W/(h•kg) at 500.0 W/kg of power density. These satisfactory performances prove that combining Ti3C2Tx MXene nanosheets with porous carbon microspheres is a considering method to construct a new generation electrode material of supercapacitor.
Image detection technology is of paramount importance across various fields. This significance is not only seen in general images with everyday scenes but also holds substantial research value in the ...field of remote sensing. Remote sensing images involve capturing images from aircraft or satellites. These images typically feature diverse scenes, large image formats, and varying imaging heights, thus leading to numerous small-sized targets in the captured images. Accurately identifying these small targets, which may occupy only a few pixels, is a challenging and active research area. Current methods mainly fall into two categories: enhancing small target features by improving resolution and increasing the number of small targets to bolster training datasets. However, these approaches often fail to address the core distinguishing features of small targets in the original images, thus resulting in suboptimal performance in fine-grained classification tasks. To address this situation, we propose a new network structure DDU (Downsample Difference Upsample), which is based on differential and resolution changing methods in the Neck layer of deep learning networks to enhance the recognition features of small targets, thus further improving the feature richness of recognition and effectively solving the problem of low accuracy in small target object recognition. At the same time, in order to take into account the recognition effect of targets of other sizes in the image, a new attention mechanism called PNOC (protecting the number of channels) is proposed, which integrates small target features and universal object features without losing the number of channels, thereby increasing the accuracy of recognition. And experimental verification was conducted on the PASCAL-VOC dataset. At the same time, it was applied to the testing of the fine-grained MAR20 dataset and found that the performance was better than other classic algorithms. At the same time, because the proposed framework belongs to a one-stage detection method, it has good engineering applicability and scalability, and universality in scientific research applications are good. Through comparative experiments, it was found that our algorithm improved the performance of the mAP by 0.7% compared to the original YOLOv8 algorithm.
Individual tree detection and counting in unmanned aerial vehicle (UAV) imagery constitute a vital and practical research field. Vegetation remote sensing captures large-scale trees characterized by ...complex textures, significant growth variations, and high species similarity within the vegetation, which presents significant challenges for annotation and detection. Existing methods based on bounding boxes have struggled to convey semantics information about tree crowns. This paper proposes a novel deep learning network called VrsNet based on the density map information. The proposed work pioneers the segmentation and counting application by utilizing the semantic information of Gaussian contour. Besides, we sample and create the UAV vegetation remote sensing density dataset TreeFsc for experiments. In quantitative comparison across multiple datasets, the proposed method demonstrates high performance, with a 3.45 increase in MAE and a 4.75 increase in RMSE. Experiments demonstrate superior cross-region, cross-scale, and cross-species target detection capabilities of the proposed approach compared with the existing object detection methods. Our code and dataset are available at: https://github.com/luotiger123/VrsNet/tree/main/VrsNet.
•Pioneer the density detection networks for extracting and counting individual trees.•Leverage the semantic information encoded in density maps for segmentation tasks.•Overcome challenges posed by complex textures and heterogeneity in vegetation mapping.•Propose a novel correlated feature extraction structure to enhance the accuracy.
Abstract
In the process of manufacturing the world’s largest silicon carbide (SiC) aspheric mirror, the primary difficulties are mirror blank preparation, asphere fabrication, and testing, as well as ...cladding and coating. Specifically, the challenges include the homogeneity of the complicated structure casting, accuracy and efficiency of the fabrication process, print-through effect, fidelity and precision of test procedure, stress and denseness of cladding process, the dynamic range of interferometric measurement, and air turbulence error due to the long optical path. To break through such a barrier of difficulties, we proposed the water-soluble room temperature vanishing mold and gel casting technology, homogeneous microstructure reaction-formed joint technology, nano-accuracy efficient compound fabrication, gravity unloading technology, high-denseness low-defect physical vapor deposition (PVD) Si-cladding technology, test data fusion method, and time-domain averaging method, etc. Based on the proposed technologies and methods, we have accomplished the world’s largest SiC aspheric mirror with a size of ⌀4.03 m. The impressive performance of the SiC aspheric mirror is validated by the characteristics of the fabricated SiC aspheric mirror. The aerial density of the SiC blank is less than 120 kg/m
2
, surface shape test accuracy is better than 6 nm RMS, thickness inhomogeneity of the cladding layer is less than 5%, and the final surface figure error and roughness are 15.2 nm RMS and 0.8 nm RMS, respectively.
Three-dimensional printing, also called additive manufacturing (AM), offers a new vision for optical components in terms of weight reduction and strength improvement. A truss, which is a triangulated ...system of members that are structured and connected in such a way that they mainly bear axial force, is commonly used in steel structures to improve stiffness and reduce weight. Combining these two technologies, an extremely lightweight truss-structured mirror was proposed. First, the finite element analyses (FEA) on surface shape deviation and modal properties were carried out. Results showed that the mirrors had sufficient stiffness and a high weight reduction of up to 85%. In order to verify their performance, the truss-structured mirror blanks were fabricated with AM technology. After that, both the preprocessing and the postprocessing of the mirrors were carried out. The results show that without NiP coating, a surface shape deviation of 0.353λ (PV) and 0.028 λ (RMS) (λ = 632.8 nm) with a roughness of Ra 2.8 nm, could be achieved. Therefore, the truss-structured mirrors in this study have the characteristics of being extremely lightweight and having improved stiffness as well as strong temperature stability.
Autophagy serves as a dynamic degradation and recycling system that provides biological materials and energy in response to stress. The role of autophagy in tumor development is complex. Various ...studies suggest that autophagy mainly contributes to tumor suppression during the early stage of tumorigenesis and tumor promotion during the late stage of tumorigenesis. During the tumorization of normal cells, autophagy protects genomic stability by retarding stem cells-involved damage/repair cycle, and inhibits the formation of chronic inflammatory microenvironment, thus protecting normal cell homeostasis and preventing tumor generation. On the other hand, autophagy also protects tumor cells survival during malignant progression by supporting cellular metabolic demands, decreasing metabolic damage and supporting anoikis resistance and dormancy. Taken together, autophagy appears to play a role as a protector for either normal or tumor cells during the early or late stage of tumorigenesis, respectively. The process of tumorigenesis perhaps needs to undergo twice autophagy-associated screening. The normal cells that have lower autophagy capacity are prone to tumorization, and the incipient tumor cells that have higher autophagy capacity possibly are easier to survival in the hash microenvironment and accumulate more mutations to promote malignant progression.
Owing to the structural errors in the optical phased array, an initial random phase reduces the quality of the deflection beam. The most commonly applied approach to phase calibration is based on ...adaptive optics. However, adaptive optimisation approaches have slow convergence and low diffraction efficiency. We proposed a pointwise optimisation approach to achieve fast and accurate beam deflection. This approach conducts phase calibration, combining global traversal and local searches individually for each array element. We built a phase-calibration optical system containing a one-dimensional optical waveguide phase array for further verification and designed the relevant mechanics. The simulation and experimental results demonstrate that the pointwise optimisation approach accelerates the calibration process and improves the diffraction efficiency.
PDF
