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In this paper, high-temperature storage of hydrogen-treated AlGaN/GaN HEMTs is conducted for the first time to study the effect of high temperature on the electrical characteristics of the devices after hydrogen treatment, and it is found that high-temperature storage can effectively reduce the impact of hydrogen on the devices. After hydrogen treatment, the output current and the maximum transconductance of the device increase, and the threshold voltage drifts negatively. However, after high-temperature treatment at 200 °C for 24 h, the output current, threshold voltage, and the maximum transconductance of the device all approach their initial values before hydrogen treatment. By using low-frequency noise analysis technology, the trap density of the hydrogen-treated AlGaN/GaN HEMT is determined to be 8.9 × 1023 cm−3·eV−1, while it changes to 4.46 × 1022 cm−3·eV−1 after high-temperature storage. We believe that the change in the electrical characteristics of the device in hydrogen is due to the passivation of hydrogen on the inherent trap of the device, and the variation in the electrical properties of the device in the process of high-temperature storage involves the influence of two effects, namely the dehydrogenation effect and the improvement of the metal–semiconductor interface caused by high temperatures.

The cohesive performance and durability of the bonding layer with semiconductor substrates are of paramount importance for realizing the high thermal conductivity capabilities of diamond. Utilizing electron beam evaporation and the room-temperature, low-pressure bonding process, robust adhesion between diamonds and silicon substrates has been achieved through the application of the metal modification layer comprised of Ti/Cu/Ti/Au (5/300/5/50 nm). Characterization with optical microscopy and atomic force microscopy reveals the uniformity and absence of defects on the surface of the deposited layer. Observations through X-ray and scanning acoustic microscopy indicate no discernible bonding defects. Scanning electron microscopy observation and energy-dispersive spectroscopy analysis of the fracture surface show distinct fracture features on the silicon substrate surface, indicating that the bonding strength of the Ti/Cu/Ti/Au metallization layer surpasses that of the base material. Furthermore, the fracture surface exhibits the presence of Cu and trace amounts of Ti, suggesting that the fracture also occurs at the interface between Ti and Cu. Characterization of the metal modification layer using X-ray diffraction reveals significant lattice distortion in the Ti layer, leading to noticeable stress accumulation within the crystalline structure. Thermal–mechanical fatigue simulations of the Ti/Cu/Ti/Au metal modification layer indicate that, owing to the difference in the coefficient of thermal expansion, the stress exerted by the Cu layer on the Ti layer results in the accumulation of fatigue damage within the Ti layer, ultimately leading to a reduction in its strength and eventual failure.

Due to the growing demand for ultra-high-density integrated circuits in the integrated circuit industry, flip-chip bonding (FCB) has become the mainstream solution for chip interconnection. In flip-chip bonding (FCB), however, alloy solder is no longer adequate to meet the high heat dissipation demands of high-power devices with over 100 kW/cm2 in power density due to its low reflow temperature. Nano-silver solder, on the other hand, exhibits superior thermal and electrical conductivity, making it an excellent alternative to traditional solder for FCB. This study explored nano-silver’s thermal reliability and electrical performance as a solder material. The following results were obtained through temperature cycle (with temperatures ranging from −55 to 150 °C) and high-temperature storage experiments (with applied temperatures of over 170 °C). The results indicate that as the duration of the high-temperature storage increased, the grain continued to coarsen, resulting in an average pore size transition from 0.004 to 0.072 μm2. A strong correlation coefficient of 0.9913 was observed between the duration of high-temperature exposure and the porosity within the time range of 0–200 h. Following the reliability test, the shear strength of the nano-silver interconnect samples showed varying degrees of decrease. The bonding effect with the nano-silver layer can be enhanced, and the thermal reliability can be improved by depositing Ni/Ag on the surface of Cu, making it less prone to cracking. Regarding the electrical performance, the square resistance of the nano-silver interconnect structures increased by 35% after the reliability test. This indicates a significant degradation in the electrical reliability of nano-silver interconnects under temperature stress.

Owing to the high power density, excellent operational stability and fast charge/discharge rate, and environmental friendliness, the lead-free Na0.5Bi0.5TiO3 (NBT)-based relaxor ferroelectrics exhibit great potential in pulsed power capacitors. Herein, novel lead-free (1−x)(0.7Na0.5Bi0.5TiO3-0.3Sr0.7Bi0.2TiO3)-xBi(Mg0.5Zr0.5)O3 (NBT-SBT-xBMZ) relaxor ferroelectric ceramics were successfully fabricated using a solid-state reaction method and designed via compositional tailoring. The microstructure, dielectric properties, ferroelectric properties, and energy storage performance were investigated. The results indicate that appropriate Bi(Mg0.5Zr0.5)O3 content can effectively enhance the relaxor ferroelectric characteristics and improve the dielectric breakdown strength by forming fine grain sizes and diminishing oxygen vacancy concentrations. Therefore, the optimal Wrec of 6.75 J/cm3 and a η of 79.44% were simultaneously obtained in NBT-SBT-0.15BMZ at 20 °C and 385 kV/cm. Meanwhile, thermal stability (20–180 °C) and frequency stability (1–200 Hz) associated with the ultrafast discharge time of ~49.1 ns were also procured in the same composition, providing a promising material system for applications in power pulse devices.

Electrocaloric properties of [110] and [111] oriented 0.73Pb(Mg1/3Nb2/3)O3-0.27PbTiO3 single crystals were studied in the temperature range of 293–423 K. The Maxwell relations and the Landau–Ginsburg–Devonshire (LGD) phenomenological theory were employed as the indirect method to calculate the electrocaloric properties, while a high-resolution calorimeter was used to measure the adiabatic temperature change of the electrocaloric effect (ECE) directly. The results indicate that the directly measured temperature changes of ΔT > 2.5 K at room temperature were procured when the applied electric field was reversed from 1 MV/m to −1 MV/m, which are larger than those deduced pursuant to the Maxwell relation, and even larger than those calculated using the LGD theory in the temperature range of 293–~380 K.

Marine microbial secondary metabolites with diversified structures have been found as promising sources of anti-inflammatory lead compounds. This review summarizes the sources, chemical structures, and pharmacological properties of anti-inflammatory natural products reported from marine microorganisms in the past three years (2021–2023). Approximately 252 anti-inflammatory compounds, including 129 new ones, were predominantly obtained from marine fungi and they are structurally divided into polyketides (51.2%), terpenoids (21.0%), alkaloids (18.7%), amides or peptides (4.8%), and steroids (4.3%). This review will shed light on the development of marine microbial secondary metabolites as potential anti-inflammatory lead compounds with promising clinical applications in human health.

This paper presents a study to evoke rat cortical functional activities, including hemodynamic and neural tissue signal changes, by monopulse electrical stimulation with a microelectrode array using functional optical coherence tomography (fOCT). Based on the principal component analysis and fuzzy clustering method (PCA-FCM), the hemodynamic response of different size blood vessels in rat cortex are analyzed, showing that the hemodynamic response of the superficial large blood vessels is more concentrated. In the regions of neural tissue where blood vessels are removed, positive significant pixels (the intensity of the pixel for five consecutive frames is greater than the average value plus triple standard deviation) and negative significant pixels (the intensity of the pixel for five consecutive frames is less than the average value minus triple standard deviation) exist, and the averaged intensity signal responds rapidly with an onset time of ~20.8 ms. Furthermore, the hemodynamic response was delayed by ~3.5 s from the neural tissue response. fOCT can provide a label-free, large-scale and depth-resolved map of cortical neurovascular activation, which is a promising technology to monitor cortical small-scale neurovascular activities.

Aerosol particle contamination in high-power laser facilities has become a major cause of internal optical component damage resistance and service life reduction. In general, contaminating particles primarily originate from stray light; therefore, it is crucial to investigate the mechanism and dynamics of the dynamic contaminating particle generation to control the cleanliness level. In this study, corresponding research was conducted on experiments and theory. We investigated the particle generation and surface composition modification under the action of a laser. We employed various surface analytical methods to identify the possible variations in the aluminum alloy surface during laser irradiations. A theoretical model for particle ejection from aluminum alloy surfaces was established by taking the adhesion force and laser cleaning force (due to thermal expansion) into account. The results show that the threshold energies for contamination particle generation and damage are around 0.1 and 0.2 J/cm2, respectively. Subsurface impurities are the primary source of particles, and particle adhesion density is related to surface roughness. Pollution particle generation and splashing processes include temperature increases, phase changes, impact diffusion, and adhesion. The results provide a reference for the normal operation of high-energy laser systems. The results also suggest that the laser irradiation pretreatment of aluminum alloy surfaces is essential to improve the cleanliness level.

SiO2 sol-gel antireflection film coated on fused silica can reduce the reflection loss and improve the transmittance of the optical component, although it is still prone to laser induced damage. Laser conditioning is an effective way to improve the laser induced damage threshold (LIDT) of SiO2 sol-gel antireflection film. In this paper, single-layer SiO2 sol-gel antireflection films pretreated by triple-frequency laser with different parameters are characterized by the macroscopical parameters, such as transmittance, refractive index, and thickness. The law of surface modification and the defect removal mechanism of the SiO2 sol-gel antireflection film by laser conditioning are obtained. It is found that laser conditioning can reduce the thickness of the film and introduce densification. In addition, laser conditioning can eliminate micro-defects, such as vacancies and voids in the preparation of SiO2 sol-gel antireflection films, which is the main reason to improve the laser damage resistance of films. Finally, the laser conditioning process with three step laser energy combinations of (0.2–0.6–1.0) Fth0 (zero damage threshold) is the best one to obtain high transmittance, and excellent effects on structure modification and defect removal of films. The research in this paper provides data support for the engineering application and mechanism research of laser conditioning.

The influence of residual heat on the fictive temperature modification zone of fused silica for different CO2 laser scanning time intervals was investigated to precisely control the profiles of hydrofluoric (HF) acid-etched fused silica surface, which were formed by the increasing HF acid-etching rate for fused silica with increasing fictive temperature induced by CO2 laser scanning. The surface profiles of HF acid-etched fused silica treated by different scanning time intervals of CO2 laser were measured by a stylus profilometry, and experimental results indicate that the CO2 laser scanning time intervals intensively influence the HF acid-etched surface profiles of fused silica. The increasing depth of surface profiles treated by shorter scanning time intervals shows that the fictive temperature modification zone significantly expands. Numerical simulations of the fictive temperature modification zone induced by different scanning time intervals indicate that the residual heat of CO2 laser scanning with shorter time intervals leads to a dramatical increase in the fictive temperature modification zone. By adjusting the residual heat of CO2 laser scanning intervals, various surface profiles of fused silica can be obtained by HF acid-etching of fused silica.

Magnetic surveys have been widely used in archaeological field investigations. However, conventional survey methods are often restricted by complicated field conditions and ambiguities in data interpretation. In this study, a novel magnetic survey system was designed for pre-archaeological investigation (preliminary survey prior to the archaeological excavation) based on a modified quadrotor unmanned aerial vehicle (UAV) and was successfully applied to an archaeological area with a complex landform in Huizhou, China. Results show that the target anomaly identified by UAV aeromagnetic survey corresponds well to the location of a potential archaeological site. Subsequent soil analyses further confirm the archaeological value of UAV aeromagnetic results and provide strong constraints on the interpretation of target anomalies. This study demonstrates that the newly proposed UAV aeromagnetic system can adapt to the various field conditions with the advantages of flexibility and efficiency, which has great potential for future archaeological investigations.

The incorporation of montmorillonite (MMT) into Nylon 6 can endow advantages like improved mechanical strength and thermal stability, making Nylon 6/MMT a possible ideal alternative for Nylon 66. However, the relationship between the microstructure and physical properties of nylon 6/MMT nanocomposites is unclear so far due to the complicated system, including the highly asymmetric geometry of the exfoliated MMT layer and the complicated interaction between MMT layers and entangled nylon 6 chains. Herein, we focus on two processes, namely the impact of MMT on the solidification procedure during molding and the toughness–brittleness transition during the tensile stretch, in order to elucidate the structure–property relationship of nylon 6/MMT composites. We firstly studied the solidification process of nylon 6/MMT with bending height experiments. The results showed that the solidification process occurs prior to the crystallization of nylon 6, indicating that a physical crosslinked network rather than a crystalline structure is the reason for the solidification process. Furthermore, the solidification speed has a step change at around 2 wt% MMT content, indicating that the MMT percolation network is related to the transition. We further studied the influence of MMT inclusion on the mechanical properties, and found the tensile strain at break showed a similar step change at around 2 wt% MMT content, which further confirms the existence of an MMT percolation network above 2 wt% MMT content. It was generally believed that the main effect of MMT on nylon 6 is the nanofiller enforcement; we found that the percolation effect of the highly asymmetric 2-D nanofiller plays a central role in influencing the mechanical properties and solidification behavior during molding.

To analyze the hyperspectral reflectance characteristics of rice canopies under changes in diffuse radiation fraction, experiments using different cover materials were performed in Nanjing, China, during 2016 and 2017. Each year, two treatments with different reduction ratios of diffuse radiation fraction but with similar shading rates were set in the field experiment: In T1, total solar radiation shading rate was 14.10%, and diffuse radiation fraction was 31.09%; in T2, total solar radiation shading rate was 14.42%, and diffuse radiation fraction was 39.98%, respectively. A non-shading treatment was included as a control (CK). Canopy hyperspectral reflectance, soil and plant analyzer development (SPAD), and leaf area index (LAI) were measured under shading treatments on different days after heading. The red-edge parameters (position, λ0; maximum amplitude, Dλ; area, α0; width, σ) were calculated, as well as the area, depth, and width of three absorption bands. The location of the first absorption band appeared in the range of 553–788 nm, and the second and third absorption bands appeared in the range of 874–1257 nm. The results show that the shading treatment had a significant effect on the rice canopy’s hyperspectral reflectance. Compared with CK, the canopy reflectance of T1 (the diffuse radiation fraction was 31.09%) and T2 (the diffuse radiation fraction was 39.98%) decreased in the visible light range (350–760 nm) and increased in the near-infrared range (800–1350 nm), while the red-edge parameters (λ0, Dλ, α0), SPAD, and LAI increased. On the other hand, under shading treatment, the increase in diffuse radiation fraction also had a significant impact on the hyperspectral spectra of the rice canopy, especially at 14 days after heading. Compared with T1, the green peak (550 nm) of T2 reduced by 16.12%, and the average reflectance at 800–900 nm increased by 10%. Based on correlation analysis, it was found that these hyperspectral reflectance characteristics were mainly due to the increase in SPAD (2.31%) and LAI (7.62%), which also led to the increase in Dλ (8.70%) and α0 (13.89%). Then, the second and third absorption features of T2 were significantly different from that of T1, which suggests that the change in diffuse radiation fraction could affect the process of water vapor absorption by rice.

The reactive ion etching (RIE) process of fused silica is often accompanied by surface contamination, which seriously degrades the ultraviolet laser damage performance of the optics. In this study, we find that the contamination behavior on the fused silica surface is very sensitive to the RIE process which can be significantly optimized by changing the plasma generating conditions such as discharge mode, etchant gas and electrode material. Additionally, an optimized RIE process is proposed to thoroughly remove polishing-introduced contamination and efficiently prevent the introduction of other contamination during the etching process. The research demonstrates the feasibility of improving the damage performance of fused silica optics by using the RIE technique.