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GaN-based Micro-LEDs, representative devices of third-generation wide-bandgap semiconductors, exhibit significant nonlinear photoluminescence (PL) properties under ultrafast femtosecond laser excitation, governed predominantly by multiphoton absorption processes. In this study, we systematically investigate photocarrier transport and recombination dynamics under various bias voltages and excitation powers using an ultrafast (∼7.5 fs) femtosecond spectroscopy system. Experimental results indicate that applying forward bias enhances PL emission dramatically by promoting radiative recombination within localized states in quantum wells, due to increased quantum-well energy-band tilting. Conversely, a reverse bias flattens the quantum-well band structure, significantly facilitating carrier drifting, thereby suppressing radiative recombination and enhancing photovoltage responses. The power-dependent analysis further reveals that nonlinear PL responses exhibit power law fitting slopes consistently greater than 2, confirming the active involvement of multiphoton absorption mechanisms. Based on these findings, a comprehensive “field modulation - nonlinear excitation” model is proposed, providing essential theoretical insights and experimental support for the future design and optimization of high-speed optoelectronic devices and highly integrated Micro-LED display applications.

The emergence and rapid development of the Internet of Medical Things (IoMT), an application of the Internet of Things into the medical and healthcare systems, have brought many changes and challenges to modern medical and healthcare systems. Particularly, machine learning technology can be used to process the data involved in IoMT for medical analysis and disease diagnosis. However, in this process, the disclosure of personal privacy information must receive considerable attentions especially for sensitive medical data. Cluster analysis is an important technique for medical analysis and disease diagnosis. To enable privacy-preserving cluster analysis in IoMT, this paper proposed an Efficient Differentially Private Data Clustering scheme (EDPDCS) based on MapReduce framework. In EDPDCS, we optimize the allocation of privacy budgets and the selection of initial centroids to improve the accuracy of differentially private K-means clustering algorithm. Specifically, the number of iterations of the K-means algorithm is set to a fixed value according to the total privacy budget and the minimal privacy budget of each iteration. In addition, an improved initial centroids selection method is proposed to increase the accuracy and efficiency of the clustering algorithm. Finally, we prove that the proposed EDPDCS can improve the accuracy of the differentially private k-means algorithm by comparing the Normalized Intra-Cluster Variance (NICV) produced by our algorithm on two datasets with two other algorithms.

Ecological sensitivity is an essential indicator for measuring the ecological environment’s level, and its assessment results have significant reference value for regional ecological environment protection and resource development and utilization. Taking Xifeng County as the study area, we selected a total of 12 assessment factors in terms of ecological environment, geological environment, and human environment, including average annual rainfall, average annual temperature, average annual wind speed, river density, vegetation coverage, soil erodibility, elevation, slope, geological disaster susceptibility, road density, land use, and night light index, and explored the spatial distribution patterns of ecological sensitivities and the characteristics of the differences in the study area based on the coefficient of variation method and machine learning. The results show that the overall spatial distribution pattern of ecological sensitivity in Xifeng County shows a low sensitivity in the north and a high sensitivity in the south. 41.90% of the regional ecological sensitivity intensity is classified as very high and high sensitivity, mainly distributed in mountainous and hilly areas, while 35.51% is classified as very low and low sensitivity, mainly distributed in plains and low mountainous areas. The assessment results are consistent with the actual situation, enriching the ecological sensitivity assessment methods and models.

Check dams are often damaged by boulder impacts. Thus, this paper proposes a novel ground-anchored string beam debris flow grille dam. Finite element software analyses showed that the novel structure outperformed the conventional grizzly dam. Reliability-based vulnerability analyses can evaluate the load-carrying capacity of check dams. The physical vulnerability of check dams to debris flows is defined as the potential damage to dams for a given debris flow intensity. Consequently, four damage states of novel structures are defined, namely, slight, moderate, heavy, and complete damage. The boulder radius (R) and flow velocity (V) were found to have the greatest effect on the failure probability using the random forest regression method. R or V single strength indicator is not sufficient to indicate novel structural damage failure probability. The impact forces V1.2R2 and V2R3 both well quantify the impact strength of the boulders. However, when considering the depth of the debris flow (H), the impact force HV1.2R2 is more appropriate to quantify the impact strength of the boulders. The fragility curve of the novel structure was obtained using the modified elastic impact force model. The novel structural failure mechanism is dominated by bending damage. The flow depth (H) affects the exceeding probability of complete damage significantly. The optimization of the novel structure is given based on the vulnerability analysis. The damage mechanisms of novel and conventional structures were analyzed. The results indicated that conventional structures exhibited the highest probability of overturning. This is the most unfavorable situation. It is further indicated that the incorporation of string beams and prestressed anchors into the novel structure can markedly enhance its performance.

In the long-distance thermal air heating process of large space buildings, there are common problems of thermal air trajectory deflection and low energy efficiency caused by thermal buoyancy. This study proposes an induced air supply system that is easy to design for integration; that is, adding a high-velocity ambient temperature induced airflow above the thermal jet, which can instantly and efficiently suppress the buoyancy of the thermal jet and maintain its axial center temperature, thereby achieving good heating performance. This study uses a numerical simulation method to analyze the effect of the induced airflow and compares the flow field characteristics and heating performance of a single thermal jet and an induced air supply system. The results show that the greater the velocity of the induced airflow, the wider the control range of the thermal jet; the induced airflow can reduce the mixing of the thermal jet and the ambient airflow, and effectively suppress the deflection of the thermal jet and increase its axial center temperature; when the target area is close to the air inlet (y/D ≤ 7.5), the single thermal jet air supply can be used, because too small a deflection height will cause more induced airflow to enter the target area, which will worsen the heating effect. The induced air supply system is best for improving the average temperature of the target area at y/D = 15; as the target distance increases, on the premise of ensuring the blowing feeling, it is possible to consider increasing the induced airflow velocity to obtain a higher heating gain.

A successful therapeutic outcome in the treatment of solid tumours requires efficient intratumoural drug accumulation and retention. Here we demonstrate that zinc gluconate in oral supplements assembles with plasma proteins to form ZnO nanoparticles that selectively accumulate into papillary Caki-2 renal tumours and promote the recruitment of dendritic cells and cytotoxic CD8 + T cells to tumour tissues. Renal tumour targeting is mediated by the preferential binding of zinc ions to metallothionein-1X proteins, which are constitutively overexpressed in Caki-2 renal tumour cells. This binding event further upregulates intracellular metallothionein-1X expression to induce additional nanoparticle binding and retention. In both tumour animal models and human renal tumour samples, we show that ZnO nanoparticles actively cross the vascular wall to achieve high intratumoural accumulation. We further explore this feature of ZnO nanoparticles for the delivery of chemotherapeutics to mouse and rabbit cancer models. Our findings demonstrate that ZnO nanoparticles derived from supplements can serve as a multifunctional drug delivery and cancer immunotherapy platform. Zinc gluconate in oral supplements associates with plasma proteins to form renal-tumour-accumulating ZnO nanoparticles, which have antitumoural immune activity and can also be used for the delivery of chemotherapeutic agents.

Vortex ventilation, which utilizes vortex airflow to effectively transport pollutants over long distances, is a promising method for pollution control in large spatial structures. The performance of vortex ventilation heavily depends on the stable generation and maintenance of column vortex airflow, necessitating a comprehensive understanding of the interactions among supply airflow, exhaust airflow, and pollutant airflow. In this study, experimental method and transient computational fluid dynamics (CFD) method were employed to quantitatively analyze the influence of supply airflow characteristics and parameters on the formation of vortex airflow. It was found that impingements between supply jet streams significantly affect the generation of vortex ventilation. Based on variations in the flow shape of supply jet streams, the process of vortex airflow formation can be divided into three stages: initiation, oscillation, and stabilization. As the airflow rate increases, the impingement effect between the air jet streams makes the vortex unstable and the vortex intensity decreases. Optimization strategies were proposed to modify system geometry, including increasing the number of supply air inlets, adjusting the horizontal deflection angle of supply air, and enlarging the size of supply air inlets. Increasing the horizontal deflection angle of supply air was shown to minimize the negative pressure within the flow field to a minimum of −12 Pa and reduce the coefficient of variation to a minimum of 0.01, which proved most effective in enhancing vortex stability.

A novel spin polarization separation of reflected light is observed, when a linearly polarized Gaussian beam impinges on an air-glass interface at Brewster angle. In the far-field zone, spins of photons are oppositely polarized in two regions along the direction perpendicular to incident plane. Spatial scale of this polarization is related to optical properties of dielectric and can be controlled by experimental configuration. We believe that this study benefits the manipulation of spins of photons and the development of methods for investigating optical properties of materials.

The variation of polarization distribution of reflected beam at specular interface and far field caused by spin separation has been studied. Due to the diffraction effect, we find a distinct difference of light polarization at the two regions. The variation of polarization distribution of reflected light provides a new method to measure the spin separation displacement caused by Spin Hall Effect of light.