Photocatalysis is a green approach to solving energy and environmental problems, and researchers are still pursuing high-performance photocatalysts. Although BiOX (X = Cl or Br) has a suitable ...bandgap and good stability, its photoresponse is mostly concentrated in the UV region. Conversely, SnS2 has a wide photoresponse range but exhibits perceptible photocorrosion and poor stability. To exploit the advantages of both BiOX and SnS2, this study hydrothermally synthesized and introduced superfine SnS2 (∼30 nm in size) into a BiOCl/BiOBr binary system to fabricate BiOCl/BiOBr/SnS2 composites. Subsequently, the degradation performance of these composites in a Rhodamine B solution under visible light was investigated. Results show that the BiOCl/BiOBr/SnS2 heterojunctions were successfully prepared and the composites exhibited the best photocatalytic performance with 6% mass fraction of SnS2 (BiOCl-to-BiOBr mol ratio = 1:1). The formation of a double S-schedule heterojunction between BiOCl/BiOBr and SnS2 not only accelerated charge separation and transfer but also broadened the photoresponse range and reduced photoelectron–hole recombination under full-spectrum irradiation. Loading a small narrow-bandgap photocatalyst onto a large photocatalyst provides an effective way to construct heterojunctions with excellent photocatalytic performance. The ternary photocatalyst presents a favorable photocatalytic stability, and its photodegradation rate is 4.6, 4.5 and 220.5 times that of BiOCl, BiOBr and SnS2, respectively.
•SnS2 particles with wide photoresponse range and fine size were synthesized.•BiOCl, BiOBr and SnS2 form visible-light responsive S-type heterojunctions.•Small SnS2 shortens electron transport paths in the ternary heterojunction.•Double S-scheme greatly improves photocatalytic performance of the heterojunctions.
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•g-C3N4/Ag2MoO4/AgBr heterojunction was prepared using a facile process.•The catalyst showed effective degradations of RhB and TCH under visible-light.•More effective charge ...separation was achieved via the ternary heterojunction.•A possible dual Z-scheme mechanism of photocatalytic degradation was proposed.
Recently, the photocatalytic degradation of organic pollutants has gained increasing attention because of its high efficiency and lack of secondary pollution; however, problems such as rapid electron–hole recombination affect its degradation efficiency. In this study, a novel dual Z-scheme g-C3N4/Ag2MoO4/AgBr heterojunction was successfully prepared using a one-step room-temperature precipitation method, with its photocatalytic activity evaluated by degrading rhodamine B (RhB) and tetracycline hydrochloride (TCH). The composition and surface morphology of the ternary catalysts—characterized using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET) tests, and X-ray photoelectron spectroscopy (XPS)—confirmed the successful loading of Ag2MoO4 and AgBr onto g-C3N4. Catalytic degradation results showed that the ternary catalyst exhibited the best performance at a 40 % mass fraction of AgBr. Moreover, the ultraviolet–visible diffuse reflectance spectra (UV–Vis DRS), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and transient photocurrent response test results show that the ternary catalyst has excellent optical properties. In addition, the significant improvement in the catalytic performance can be attributed to the effective charge separation of the dual Z-scheme photocatalytic mechanism based on radical trapping experiments, electron spin resonance (ESR) analysis, and energy band analysis. Hence, this study provides a new approach to studying more efficient photocatalysts.
Electroless nickel composite coatings have the potential for high-temperature tribological applications, and a combination of high wear resistance and low friction factor is one of the desirable ...solutions but still a tricky problem. The addition of self-lubricating WSsub.2 and hard Sisub.3 Nsub.4 nanoparticles to the Ni-P coatings is expected to obtain good high-temperature tribological performance. In this work, Ni-P-Sisub.3 Nsub.4 -WSsub.2 composite coatings with various contents of WSsub.2 nanoparticles were prepared using electroless plating and subsequently annealed at 400 °C in an inert atmosphere. The tribological properties of the coatings were evaluated using a ball-on-disc wear instrument at operating temperatures from 25 to 600 °C. The microstructure, chemical composition, and surface morphology of the coatings were characterized by X-ray diffractometry (XRD), energy disperse spectroscopy (EDS), and scanning electron microscopy (SEM). Upon increasing the WSsub.2 dosage in the bath, the WSsub.2 content in the coating increased and the micro-hardness of the as-plated coating increased from 539 to 717 HV. After heat treatment, the coating underwent a crystallization process, and the hardness increased from 878 to 1094 HV. The main wear mechanism of the coating changed from adhesive wear in the as-plated state to abrasive wear in the annealed state. The annealed Ni-P-Sisub.3 Nsub.4 -WSsub.2 coating with a WSsub.2 dosage of 2.5 g/L in the bath exhibited excellent mechanical properties, with a hardness of 10.9 GPa, a friction coefficient of ~0.51, and a wear rate of 8.4 × 10sup.−15 msup.3 Nsup.−1 ⋅msup.−1 at room temperature, and maintained optimal performance at high temperatures. At operating temperatures of 200, 400, and 600 °C, the form of wear was adhesive wear for coatings with a WSsub.2 dosage <1.5 g/L and abrasive wear for coatings with a WSsub.2 dosage ≥1.5 g/L. The synergism of WSsub.2 and Sisub.3 Nsub.4 particles refined the grains of the Ni-P matrix in as-plated coatings and obviously reduced the friction coefficient of friction pairs in annealed coatings at all operating temperatures.
Electroless nickel composite coatings have the potential for high-temperature tribological applications, and a combination of high wear resistance and low friction factor is one of the desirable ...solutions but still a tricky problem. The addition of self-lubricating WS2 and hard Si3N4 nanoparticles to the Ni-P coatings is expected to obtain good high-temperature tribological performance. In this work, Ni-P-Si3N4-WS2 composite coatings with various contents of WS2 nanoparticles were prepared using electroless plating and subsequently annealed at 400 °C in an inert atmosphere. The tribological properties of the coatings were evaluated using a ball-on-disc wear instrument at operating temperatures from 25 to 600 °C. The microstructure, chemical composition, and surface morphology of the coatings were characterized by X-ray diffractometry (XRD), energy disperse spectroscopy (EDS), and scanning electron microscopy (SEM). Upon increasing the WS2 dosage in the bath, the WS2 content in the coating increased and the micro-hardness of the as-plated coating increased from 539 to 717 HV. After heat treatment, the coating underwent a crystallization process, and the hardness increased from 878 to 1094 HV. The main wear mechanism of the coating changed from adhesive wear in the as-plated state to abrasive wear in the annealed state. The annealed Ni-P-Si3N4-WS2 coating with a WS2 dosage of 2.5 g/L in the bath exhibited excellent mechanical properties, with a hardness of 10.9 GPa, a friction coefficient of ~0.51, and a wear rate of 8.4 × 10−15 m3N−1⋅m−1 at room temperature, and maintained optimal performance at high temperatures. At operating temperatures of 200, 400, and 600 °C, the form of wear was adhesive wear for coatings with a WS2 dosage <1.5 g/L and abrasive wear for coatings with a WS2 dosage ≥1.5 g/L. The synergism of WS2 and Si3N4 particles refined the grains of the Ni-P matrix in as-plated coatings and obviously reduced the friction coefficient of friction pairs in annealed coatings at all operating temperatures.
With the increase in people’s concern for personal health, the demand for convenient health monitoring electronics has grown noticeably. Wearable physiological sensors with multi-functionality and ...continuous power supply are constructed through system-level integration and delicate circuit design for energy management and low-power sensing. Energy harvested from body motion and solar or domestic lighting has great potential in powering wearable electronics, eliminating the need of batteries or plug-in power sources. Triboelectric nanogenerators readily fabricated with digital ink-jet printing display a high-power output of 30.96 mW/cm2 after integration with a flexible thin-film solar cell, which ensures unremitting work of the sensors. The self-powered physiological monitoring system can continuously monitor and wirelessly transmit the electrocardiogram, blood pressure, temperature, and motion parameters of the human in real-time without the need for an external power source, providing the wearer with a reliable monitoring means.
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•The friction and solar power generators complement each other to supply for sensor components power.•It efficiently realizes high integration of power, multi-modal sensing, and wireless transmission.•The efficient sensing and transmission circuit provides the system to monitor the user’s physiological signals.
Intelligent reflecting surface (IRS) and non-orthogonal multiple access (NOMA) are both powerful means to improve the spectrum efficiency and can assist the cognitive radio network (CRN) in achieving ...more effective spectrum allocation. However, spectrum sharing in CRNs and the utilization of the scarce bandwidth in NOMA make it vulnerable to security threats. The secure beamforming design in IRS-assisted CRNs with NOMA is complicated and non-convex. Traditional semidefinite relaxation along with Gaussian randomization (SDR-GR) algorithm can solve the non-convex problem, however a high computational complexity. This paper proposes an alternating direction method of multipliers (ADMM)-based sum secrecy rate maximization (A-SSRM) scheme to achieve secure transmission with low computation complexity in IRS-assisted uplink CRNs with NOMA. Specifically, we derive an appropriate transformation of the original problem based on the ADMM framework and decompose it into multiple sub-problems, which are carefully designed to have closed-form solutions. Furthermore, an eavesdropper zero forcing (EZF)-based sub-optimal scheme is presented. Simulation results reveal that our proposed A-SSRM scheme outperforms other benchmarks in terms of sum secrecy rate and reduces the average running time by 6 times compared with the traditional SDR-GR algorithm. This is attributed to our effective decoupling and decomposing of the original problem, which enables each sub-problem to obtain a simple closed-form solution through derivation.
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•Metallic MoS2 and amorphous CoNi(OH)2 show a synergistic effect for HER in 0.1 M KOH.•MoS2-CoNi(OH)2 composite has higher current response for HER than Pt/C at η greater ...than 0.19 V.•MoS2-CoNi(OH)2 composite also shows highly efficient OER performance in 0.1 M KOH.
We report the preparation of nanocomposite consisting of metallic MoS2 and electrodeposited amorphous CoNi(OH)2 nanosheets on carbon paper for efficient electrochemical water splitting in the alkaline solutions. The synergistic effect between metallic MoS2 and amorphous CoNi(OH)2 nanosheets enables the excellent catalytic activity of nanocompsite towards hydrogen evolution reaction (HER) in 0.1 M KOH with a low overpotential of 178 mV at a current density of 10 mA/cm2 and Tafel slope of 60.9 mV/decade. The current density of MoS2-CoNi(OH)2 nanocomposite for HER at the overpotential of more than 0.190 V is even higher than that of the commercial Pt/C catalyst. Moreover, the MoS2-CoNi(OH)2 nanocomposite is also active towards electrochemical oxygen evolution and can act as a bifunctional catalyst for water splitting in 0.1 M KOH. Our work povides a simple and effective way to engineer phases and prepare two-dimensional nanocomposites for effecient water splitting in alkaline aqueous solutions.
Histopathological examinations heavily rely on hematoxylin and eosin (HE) and immunohistochemistry (IHC) staining. IHC staining can offer more accurate diagnostic details but it brings significant ...financial and time costs. Furthermore, either re-staining HE-stained slides or using adjacent slides for IHC may compromise the accuracy of pathological diagnosis due to information loss. To address these challenges, we develop PST-Diff, a method for generating virtual IHC images from HE images based on diffusion models, which allows pathologists to simultaneously view multiple staining results from the same tissue slide. To maintain the pathological consistency of the stain transfer, we propose the asymmetric attention mechanism (AAM) and latent transfer (LT) module in PST-Diff. Specifically, the AAM can retain more local pathological information of the source domain images through the design of asymmetric attention mechanisms, while ensuring the model's flexibility in generating virtual stained images that highly confirm to the target domain. Subsequently, the LT module transfers the implicit representations across different domains, effectively alleviating the bias introduced by direct connection and further enhancing the pathological consistency of PST-Diff. Furthermore, to maintain the structural consistency of the stain transfer, the conditional frequency guidance (CFG) module is proposed to precisely control image generation and preserve structural details according to the frequency recovery process. To conclude, the pathological and structural consistency constraints provide PST-Diff with effectiveness and superior generalization in generating stable and functionally pathological IHC images with the best evaluation score. In general, PST-Diff offers prospective application in clinical virtual staining and pathological image analysis.
Radiomics refers to the high-throughput extraction of quantitative features from medical images, and is widely used to construct machine learning models for the prediction of clinical outcomes, while ...feature engineering is the most important work in radiomics. However, current feature engineering methods fail to fully and effectively utilize the heterogeneity of features when dealing with different kinds of radiomics features. In this work, latent representation learning is first presented as a novel feature engineering approach to reconstruct a set of latent space features from original shape, intensity and texture features. This proposed method projects features into a subspace called latent space, in which the latent space features are obtained by minimizing a unique hybrid loss function including a clustering-like loss and a reconstruction loss. The former one ensures the separability among each class while the latter one narrows the gap between the original features and latent space features. Experiments were performed on a multi-center non-small cell lung cancer (NSCLC) subtype classification dataset from 8 international open databases. Results showed that compared with four traditional feature engineering methods (baseline, PCA, Lasso and L2,1-norm minimization), latent representation learning could significantly improve the classification performance of various machine learning classifiers on the independent test set (all p <0.001). Further on two additional test sets, latent representation learning also showed a significant improvement in generalization performance. Our research shows that latent representation learning is a more effective feature engineering method, which has the potential to be used as a general technology in a wide range of radiomics researches.
There is a lack of accurate pediatric reference intervals (RIs) in China, with most commonly used RIs established without consideration of the effect of age and gender. The Pediatric Reference ...Intervals in China (PRINCE) project aims to establish and verify pediatric RIs for 31 common laboratory measurands. The project will be a large, multicenter cross-sectional study: 14,490 healthy children and adolescents aged up to 19 years will be surveyed by 10 children’s hospitals and one pediatric department of a university hospital. To evaluate the feasibility and efficiency of the study methods, 602 children were surveyed in the pilot phase of the PRINCE study in April 2017: it found that some measurands were distinctly age dependent and that there were differences between values for males and females. The results of the pilot study affirmed the necessity of the PRINCE project for Chinese pediatrics. The pilot also indicated potential difficulties in the full survey, e.g., difficulties in recruiting children aged under 3 years and insufficient collection of blood samples from infants. The operation of the PRINCE project has been modified based on the findings in the pilot study toward improving the validity of the PRINCE project and promoting its openness and transparency.
