Lead-halide perovskites have been attracting attention for potential use in solid-state lighting. Following the footsteps of solar cells, the field of perovskite light-emitting diodes (PeLEDs) has ...been growing rapidly. Their application prospects in lighting, however, remain still uncertain due to a variety of shortcomings in device performance including their limited levels of luminous efficiency achievable thus far. Here we show high-efficiency PeLEDs based on colloidal perovskite nanocrystals (PeNCs) synthesized at room temperature possessing dominant first-order excitonic radiation (enabling a photoluminescence quantum yield of 71% in solid film), unlike in the case of bulk perovskites with slow electron–hole bimolecular radiative recombination (a second-order process). In these PeLEDs, by reaching charge balance in the recombination zone, we find that the Auger nonradiative recombination, with its significant role in emission quenching, is effectively suppressed in low driving current density range. In consequence, these devices reach a maximum external quantum efficiency of 12.9% and a power efficiency of 30.3 lm W–1 at luminance levels above 1000 cd m–2 as required for various applications. These findings suggest that, with feasible levels of device performance, the PeNCs hold great promise for their use in LED lighting and displays.
Organometal halide perovskite has recently emerged as a very promising family of materials with augmented performance in electronic and optoelectronic applications including photovoltaic devices, ...photodetectors, and light-emitting diodes. Herein, we propose and demonstrate facile solution synthesis of a series of colloidal organometal halide perovskite CH3NH3PbX3 (X = halides) nanoparticles with amorphous structure, which exhibit high quantum yield and tunable emission from ultraviolet to near-infrared. The growth mechanism and photoluminescence properties of the perovskite amorphous nanoparticles were studied in detail. A high-efficiency green-light-emitting diode based on amorphous CH3NH3PbBr3 nanoparticles was demonstrated. The perovskite amorphous nanoparticle-based light-emitting diode shows a maximum luminous efficiency of 11.49 cd/A, a power efficiency of 7.84 lm/W, and an external quantum efficiency of 3.8%, which is 3.5 times higher than that of the best colloidal perovskite quantum-dot-based light-emitting diodes previously reported. Our findings indicate the great potential of colloidal perovskite amorphous nanoparticles in light-emitting devices.
Green citrus detection in citrus orchards provides reliable support for production management chains, such as fruit thinning, sunburn prevention and yield estimation. In this paper, we proposed a ...lightweight object detection YOLOv5-CS (Citrus Sort) model to realize object detection and the accurate counting of green citrus in the natural environment. First, we employ image rotation codes to improve the generalization ability of the model. Second, in the backbone, a convolutional layer is replaced by a convolutional block attention module, and a detection layer is embedded to improve the detection accuracy of the little citrus. Third, both the loss function CIoU (Complete Intersection over Union) and cosine annealing algorithm are used to get the better training effect of the model. Finally, our model is migrated and deployed to the AI (Artificial Intelligence) edge system. Furthermore, we apply the scene segmentation method using the "virtual region" to achieve accurate counting of the green citrus, thereby forming an embedded system of green citrus counting by edge computing. The results show that the mAP@.5 of the YOLOv5-CS model for green citrus was 98.23%, and the recall is 97.66%. The inference speed of YOLOv5-CS detecting a picture on the server is 0.017 s, and the inference speed on Nvidia Jetson Xavier NX is 0.037 s. The detection and counting frame rate of the AI edge system-side counting system is 28 FPS, which meets the counting requirements of green citrus.
With the development of agricultural information technology, the Internet of Things and blockchain have become important in the traceability of agricultural products. Sensors collect real-time data ...in agricultural production and a blockchain provides a secure and transparent storage medium for these data, which improves the transparency and credibility of agricultural product traceability. However, existing agricultural product traceability solutions are limited by the immutability of the blockchain, making it difficult to delete erroneous data and modify the scope of data sharing. This damages the credibility of traceability data and is not conducive to the exchange and sharing of information among enterprises. In this article, we propose an agricultural product traceability data management scheme based on a redactable blockchain. This scheme allows agricultural enterprises to encrypt data to protect privacy. In order to facilitate the maintenance and sharing of data, we introduce a chameleon hash function to provide data modification capabilities. Enterprises can fix erroneous data and update the access permissions of the data. To improve the efficiency of block editing, our scheme adopts a distributed block editing method. This method supports threshold editing operations, avoiding single-point-of-failure issues. We save records of data modifications on the blockchain and establish accountability mechanisms to identify malicious entities. Finally, in this paper we provide a security analysis of our proposed solution and verify its effectiveness through experiments. Compared with the existing scheme, the block generating speed is improved by 42% and the block editing speed is improved by 29.3% at 125 nodes.
To improve the comprehensive performance of pervious concrete, the properties of pervious concrete in different paste–aggregate ratios were subjected to both early CO2 curing and uncarbonated curing ...conditions. The mechanical properties, water permeability, porosity, and chemical composition of pervious concrete under two curing conditions were investigated and compared. The effects of CO2 curing on the properties of pervious concrete with different paste–aggregate ratios were derived. Through mechanical experiments, it was revealed that early CO2 curing can enhance the mechanical strength of pervious concrete by about 15–18%. Meanwhile, with the increase in the paste–aggregate ratio, the improvement effect induced by early CO2 curing became more significant. The water resistance of carbonated concrete was not significantly reduced. And with the increase in the paste–aggregate ratio, the carbonation degree of pervious concrete was reduced; the differences in porosity and water resistance became less significant when the paste–aggregate ratio exceeded 0.39. Micro-structural analysis shows that the early CO2 curing reduced both total porosity and the volume of micropores with a pore diameter of less than 40 nm, while it increased the volume of pores with a diameter of more than 40 nm. This is also the main reason that the strength of pervious concrete under early CO2 curing is higher than that without CO2 curing. The effect of varying paste–aggregate ratio and curing methods adds to the limited knowledge of the performance of pervious concrete.
To better understand the effect of the size of hole defects on the mechanical properties of a rock mass, the two-dimensional particle flow discrete element code (PFC2D) is applied to establish rock ...mass models with single circular hole defects of different diameters. Uniaxial compressive strength (UCS) tests are conducted on each model by only taking the defect size (area) as a variable. This study analyzes each model’s stress-strain, contact force chain, crack evolution, meso-damage and failure, and mechanical properties. The results showed that with the size enlargement of the circular hole defects, each model’s UCS and elastic modulus gradually decrease, and the defect size is negatively correlated with the mechanical strength of the rock samples. The size of the hole defects affects the entire process of contact force chain and crack evolution. The larger the aperture dimension of the circular hole defects in each model, the greater the concentration degree of the contact force chain, the earlier the crack initiation, and the higher the degree of crack coalescence in the post-peak stage. The number of cracks decreases as the hole size increases, and the model is more prone to failure. Rock models’ strength and failure characteristics with different numbers and arrangements of hole defects are discussed under the same defect area condition.
► A hybrid system using mid-temperature solar heat for CO2 capture was proposed. ► Work output is increased by 17.2%. ► Solar field area cost is reduced by 60% per ton CO2. ► Solar heat can be ...converted into electricity with efficiency of 27%.
This article proposed a hybrid power system combining mid-temperature solar heat and a coal-fired power plant for CO2 capture. In this system, solar heat at around 300°C replaces the high-quality steam extractions of the Rankine cycle to heat the feed water, so the steam that was to be extracted can expand efficiently in the high-pressure turbines. In this hybrid system, the CO2 capture penalty is completely compensated for by the enhanced work output contributed by the solar heat. The annual solar field cost is reduced to 10.8$/ton-CO2, compared to 25.8$/ton-CO2 in a system with solar heat for direct solvent regeneration. Additionally, the mid-temperature solar heat is converted into work with an improved efficiency of 27%. Thus, this system offers a promising approach to reduce the CO2 capture penalty in CCS with attractive cost-effective utilization of mid-temperature solar heat.
The main ocular features of the patients with FD are corneal verticillata, HRF on OCT, conjunctival vessel malformation and retinal vessel tortuosity.
These ocular manifestations should be considered ...as the diagnostic criteria of FD.
To investigate ocular abnormalities in Fabry disease (FD).
Forty-five patients with FD diagnosed by genetic analysis were enrolled in a single medical centre. The following ocular examinations were performed: slit-lamp examination, ophthalmic fundus imaging, in vivo confocal microscopy (IVCM) and optical coherence tomography (OCT). The prevalences of typical abnormalities in the cornea, conjunctiva and retina were recorded; their differences between hemizygote and heterozygote were compared.
In this study, the prevalence of corneal verticillata was 97.8% (44/45). Corneal examination with IVCM demonstrated hyper-reflective intracellular inclusions located within basal epithelial cells. Conjunctival vessel malformations were observed in 64.4% (29/45) of patients, and retinal vessel tortuosity was observed in 62.2% (28/45) of patients. OCT revealed many strong hyper-reflective foci (HRF) in the inner retinal layer (in 66.7% 30/45 of patients); these foci may represent retinal vascular plexi. The prevalences of conjunctival vessel malformation, retinal vessel tortuosity and HRF were higher in hemizygote than in heterozygote.
Corneal verticillata, HRF on OCT, conjunctival vessel malformation and retinal vessel tortuosity exhibit high prevalence in patients with FD. These ocular manifestations are characteristic and easily accessible; thus, they should be considered diagnostic criteria for FD.
Abstract
Background
Autoimmune necrotizing myopathy with anti-signal recognition particle antibodies (ANM-SRP) is regarded as refractory myositis, whereby some patients respond poorly to conventional ...immunosuppression and require B cell depletion treatment. This study aimed to evaluate factors associated with refractory ANM-SRP.
Results
Clinical and pathological data from 48 patients with ANM-SRP were collected. We followed up clinical symptoms and image changes over 12 months. Univariate and multivariate analyses were undertaken to determine the associations between variables of interest and poor response to therapy. Refractory ANM-SRP appeared in 32.5% of patients who showed no or minimal improvement after 12 months of steroid therapy. The clinical risk factors for refractory patients were being male (OR, 19.57;
P
< 0.001), severe muscle weakness (OR, 7.51;
P
< 0.001) and concurrent interstitial lung disease (OR, 39.70;
P
< 0.001). The imaging refractory-related factor was the fatty infiltration rate of thigh muscles over 3 months (
P
= 0.022) and the pathological factor associated with refractory ANM-SRP was the high expression of B cell activating factor receptor (BAFF-R) in muscle (
P
= 0.036).
Conclusion
Being male, severe muscle weakness, concurrent interstitial lung disease, quick development of muscle fatty infiltration and more BAFF-R and B lymphocyte infiltration in muscle indicate a poor response to immunosuppressive therapy in patients with ANM-SRP.
Florescence information monitoring is essential for strengthening orchard management activities, such as flower thinning, fruit protection, and pest control. A lightweight object recognition model ...using cascade fusion YOLOv4-CF is proposed, which recognizes multi-type objects in their natural environments, such as citrus buds, citrus flowers, and gray mold. The proposed model has an excellent representation capability with an improved cascade fusion network and a multi-scale feature fusion block. Moreover, separable deep convolution blocks were employed to enhance object feature information and reduce model computation. Further, channel shuffling was used to address missing recognition in the dense distribution of object groups. Finally, an embedded sensing system for recognizing citrus flowers was designed by quantitatively applying the proposed YOLOv4-CF model to an FPGA platform. The mAP@.5 of citrus buds, citrus flowers, and gray mold obtained on the server using the proposed YOLOv4-CF model was 95.03%, and the model size of YOLOv4-CF + FPGA was 5.96 MB, which was 74.57% less than the YOLOv4-CF model. The FPGA side had a frame rate of 30 FPS; thus, the embedded sensing system could meet the demands of florescence information in real-time monitoring.
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