With the increased deployment of power modules in demanding conditions, sintering materials, especially composite sintering materials, have raised growing interest due to their cost-effectiveness and suitability. Therefore, this study explores the viability of Cu–Ag composite sintering material, focusing on solvent influence through microstructure and mechanical behavior analysis. Micron-sized particle-based Cu–Ag composite pastes were designed and compared using eight solvents (four epoxy-free and four epoxy-added) based on fluidity and thermal stability. The sintered joints' performance, assessed through shear strength analysis, showed comparable values to pure silver sintering for both epoxy-free and epoxy-added samples. Optimized samples from each solvent system underwent reliability analysis, demonstrating that Cu–Ag joints with epoxy resin exhibited significantly higher shear strength after high-temperature storage and thermal cycling tests. Micromorphology and elemental composition analysis revealed differences in aging mechanisms, primarily attributed to variations in porosity due to oxide formation and pore filling by epoxy resin under different solvent systems. Further nanoindentation characterization of micromechanical properties, including hardness, modulus, and creep properties, during high-temperature aging, established constitutive models for insights into reliability evolution. In conclusion, the optimized epoxy-added Cu–Ag sintered joints proposed in this study demonstrated exceptional reliability and acceptable micromechanical properties, presenting a promising option for high-temperature power packaging.

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Driven by the need for improved quality, energy efficiency, and visual innovation, display technology has evolved from CRT to Mini LED. However, the transfer process in Mini LED assembly poses challenges in precision. This study addressed the displacement issue during the transfer process by investigating the synergistic effects of solder and functional organic chemicals. Through the Mini LED assembly process, with the Mini LED size measuring 150 μm (length) ∗ 100 μm (width) ∗ 70 μm (thickness), polyamide was identified as a facilitator for precise alignment, which enhanced self-alignment capabilities by 68.8 % and improved the accuracy on self-aligned distance from 12.5 μm to 21.1 μm in Mini LED packaging. Through the powder coalescence approach, further extensive analysis using XPS, SEM, FTIR, and DSC reveals the synergistic effects. It supports the proposed three-dimensional polyamide-tin ion coordination interfacial network construction mechanism that facilitates solder-to-solder self-alignment and coalescence. This study provides insight into such a polymer-metal ion 3D coordination network for Mini LED precise alignment, which is promising for mass production.@en

Power modules applied in offshore applications are facing risks of corrosion failures on die-attach materials due to high humidity and H₂S exposure. To investigate such corrosion behavior for sintered die-attach materials, we conducted a study with four groups of samples fabricated using copper and silver metal particles under different solvent systems. Such samples were firstly subjected to high-humidity-H₂S conditions for 168 h to simulate the harsh offshore environment. After undergoing corrosion, the primary compounds formed were CuO/Cu₂O and Ag₂S through SEM, XRD, and XPS analysis. Notably, the incorporation of epoxy resin into sintered copper joints resulted in a remarkable reduction in corrosion and a substantial improvement in electrical conductivity after the reaction. In contrast, while the addition of epoxy did not evidently reduce corrosion in silver joints, it did lead to a significant increase in shear strength. Furthermore, to gain further insights into the effect of epoxy resin on corrosion behavior, electrochemical analysis, and molecular dynamics simulations were conducted. Finally, the mechanical reliability of the corroded copper and silver joints was evaluated through thermal shock tests. In summary, sintered copper joints exhibited better anti-corrosion behaviors than sintered silver under high humidity and H₂S exposure, especially with the addition of epoxy resin. However, the corrosion products of sintered copper suffered from a sharp decrease in shear strength after thermal shock tests than sintered silver, which is probably due to the coefficient of thermal expansion mismatch.

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It is increasingly challenging to deal with the volume,variety, velocity, and veracity of misinformation (e.g., dissemination of fake news contents, spurious posts, and fabricated images/videos) from different online platforms. In this article, we present an overview of existing machine learning and information hiding-based misinformation detection techniques and discuss the current threats and limitations of these approaches. Based on the discussion, we identify a number of potential countermeasures.

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Epithelial to mesenchymal transition (EMT) is crucial during embryonic development, tissue fibrosis, and cancer progression. Epithelial cells that display a cobblestone-like morphology can undergo a switch to mesenchymal-like phenotype, displaying an elongated spindle shape or a fibroblast-like morphology. EMT is characterized by timely and reversible alterations of molecular and cellular processes. The changes include loss of epithelial and gain of mesenchymal marker expression, loss of polarity, increased cell migratory and invasive properties. Epithelial cells can progress unevenly during this transition and attain hybrid E/M states or metastable EMT states, referred to as epithelial cell plasticity. To gain a deeper insight into the mechanism of EMT, understanding the dynamic aspects of this process is essential. One of the most prominent factors to induce EMT is the cytokine transforming growth factor-β (TGF-β). This chapter discusses molecular and cellular techniques to monitor TGF-β-induced signaling and EMT changes in normal and cancer cell lines. These methods include measuring the TGF-β-induced activation of its intracellular SMAD effectors proteins and changes in epithelial/mesenchymal marker expression and localization. Moreover, we describe assays of cell migration and dynamic reorganization of the actin cytoskeleton and stress filaments that are frequently part of the TGF-β-induced EMT cellular response.

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Glacier and snow are sensitive indicators of regional climate variability. In the early 21st century, glaciers in the West Kunlun and Pamir regions showed stable or even slightly positive mass budgets, and this is anomalous in a worldwide context of glacier recession. We studied the evolution of snow cover to understand whether it could explain the evolution of glacier area. In this study, we used the thresholding of the NDSI (Normalized Difference Snow Index) retrieved with MODIS data to extract annual glacier area and snow cover. We evaluated how the glacier trends related to snow cover area in five subregions in the Tarim Basin. The uncertainty in our retrievals was assessed by comparing MODIS results with the Landsat-5 TM in 2000 and Landsat-8 OLI in 2020 glacier delineation in five subregions. The glacier area in the Tarim Basin decreased by 1.32%/a during 2000–2020. The fastest reductions were in the East Tien Shan region, while the slowest relative reduction rate was observed in the West Tien Shan and Pamir, i.e., 0.69%/a and 1.08%/a, respectively, during 2000–2020. The relative glacier stability in Pamir may be related to the westerlies weather system, which dominates climate in this region. We studied the temporal variability of snow cover on different temporal scales. The analysis of the monthly snow cover showed that permanent snow can be reliably delineated in the months from July to September. During the summer months, the sequence of multiple snowfall and snowmelt events leads to intermittent snow cover, which was the key feature applied to discriminate snow and glacier.

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The development of silicon-based high-power devices, e.g. IGBTs, has reached its application limits in terms of high-temperature and high-frequency harsh operating conditions. Wide bandgap (WBG) power devices (such as silicon carbide, SiC) are currently one of the most promising power devices for replacement. Due to their intrinsic bandgap, SiC high-power devices have proven their superior performance in high-frequency and high-temperature working scenarios. With the increasing demand of high-power semiconductor devices in industries such as new-energy vehicles, high-speed railway systems, and aerospace, the conditions of SiC power semiconductor devices have become more and more complex, which brings challenges to electronic packaging technology. Due to thermal management and reliability requirements for SiC power devices, customized advanced heat dissipation structures, and high-temperature soldering materials have been introduced in power device packaging technology. The reliability verification of these new electronic packaging technologies is often time-consuming and labor-intensive, so designers hope to obtain results consistent with actual experimental data through the utilization of computer-aided design methods, such as finite-element analysis (FEA), which will greatly reduce the number of iterations of physical prototypes and the development time. This article reviewed and discussed the application of FEA in the latest packaging technology, including the extraction of the thermal resistance network of the SiC power module, the thermal simulation of the novel efficient cooling structure, the thermo-mechanical analysis of the high-temperature packaging material, and the long-term reliability FEA of the SiC power devices.

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