During soldering and service, intermetallic compounds (IMCs) have an important impact on the performance and reliability of electronic products. A thin and continuous intermetallic layer facilitates ...the formation of reliable solder joints and improves the creep and fatigue resistance of solder joints. However, if the IMCs overgrow, the coarse IMC becomes brittle and tends to crack under stress, leading to a decrease in solder joint reliability. Based on the latest developments in the field of lead-free solders at home and abroad, this paper comprehensively reviews the interfacial reaction between SnAgCu Pb-free solders and different substrates and the growth behavior of IMCs and clarifies the growth mechanism of interfacial IMCs. The effects of the modification measures of lead-free solder on the IMCs and reliability of SnAgCu/substrate interface are analyzed, which provide a theoretical basis for the development and application of new lead-free solder.
Lung cancer is often diagnosed at an advanced stage and has a poor prognosis. Conventional treatments are not effective for metastatic lung cancer therapy. Although some of molecular targets have ...been identified with favorable response, those targets cannot be exploited due to the lack of suitable drug carriers. Lung cancer cell-derived exosomes (LCCDEs) receive recent interest in its role in carcinogenesis, diagnosis, therapy, and prognosis of lung cancer due to its biological functions and natural ability to carry donor cell biomolecules. LCCDEs can promote cell proliferation and metastasis, affect angiogenesis, modulate antitumor immune responses during lung cancer carcinogenesis, regulate drug resistance in lung cancer therapy, and be now considered an important component in liquid biopsy assessments for detecting lung cancer. Therapeutic deliverable exosomes are emerging as promising drug delivery agents specifically to tumor high precision medicine because of their natural intercellular communication role, excellent biocompatibility, low immunogenicity, low toxicity, long blood circulation ability, biodegradable characteristics, and their ability to cross various biological barriers. Several studies are currently underway to develop novel diagnostic and prognostic modalities using LCCDEs, and to develop methods of exploiting exosomes for use as efficient drug delivery vehicles. Current status of lung cancer and extensive applicability of LCCDEs are illustrated in this review. The promising data and technologies indicate that the approach on LCCDEs implies the potential application of LCCDEs to clinical management of lung cancer patients.
NH4+ ions as charge carriers show potential for aqueous rechargeable batteries. Studied here for the first time is the NH4+‐storage chemistry using electrodeposited manganese oxide (MnOx). MnOx ...experiences morphology and phase transformations during charge/discharge in dilute ammonium acetate (NH4Ac) electrolyte. The NH4Ac concentration plays an important role in NH4+ storage for MnOx. The transformed MnOx with a layered structure delivers a high specific capacity (176 mAh g−1) at a current density of 0.5 A g−1, and exhibits good cycling stability over 10 000 cycles in 0.5 M NH4Ac, outperforming the state‐of‐the‐art NH4+ hosting materials. Experimental results suggest a solid‐solution behavior associated with NH4+ migration in layered MnOx. Spectroscopy studies and theoretical calculations show that the reversible NH4+ insertion/deinsertion is accompanied by hydrogen‐bond formation/breaking between NH4+ and the MnOx layers. These findings provide a new prototype (i.e., layered MnOx) for NH4+‐based energy storage and contributes to the fundamental understanding of the NH4+‐storage mechanism for metal oxides.
NH4+ storage using electrodeposited manganese oxides (MnOx) is studied for the first time. MnOx exhibits structural transformation during charge/discharge in dilute ammonium acetate (NH4Ac) electrolyte. Experimental and theoretical results suggest that the reversible NH4+ insertion/deinsertion in layered MnOx is associated with hydrogen‐bond formation/breaking between NH4+ and the MnOx layers.
Alzheimer's disease (AD) is marked by the presence of extracellular amyloid beta (Aβ) plaques, intracellular neurofibrillary tangles (NFTs) and gliosis, activated glial cells, in the brain. It is ...thought that Aβ plaques trigger NFT formation, neuronal cell death, neuroinflammation and gliosis and, ultimately, cognitive impairment. There are increased numbers of reactive astrocytes in AD, which surround amyloid plaques and secrete proinflammatory factors and can phagocytize and break down Aβ. It was thought that neuronal cells were the major source of Aβ. However, mounting evidence suggests that astrocytes may play an additional role in AD by secreting significant quantities of Aβ and contributing to overall amyloid burden in the brain. Astrocytes are the most numerous cell type in the brain, and therefore even minor quantities of amyloid secretion from individual astrocytes could prove to be substantial when taken across the whole brain. Reactive astrocytes have increased levels of the three necessary components for Aβ production: amyloid precursor protein, β-secretase (BACE1) and γ-secretase. The identification of environmental factors, such as neuroinflammation, that promote astrocytic Aβ production, could redefine how we think about developing therapeutics for AD.
High‐energy‐density lithium (Li) metal batteries are severely hindered by the dendritic Li deposition dictated by non‐uniform solid electrolyte interphase (SEI). Despite its unique advantages in ...improving the uniformity of Li deposition, the current anion‐derived SEI is unsatisfactory under practical conditions. Herein regulating the electrolyte structure of anions by anion receptors was proposed to construct stable anion‐derived SEI. Tris(pentafluorophenyl)borane (TPFPB) anion acceptors with electron‐deficient boron atoms interact with bis(fluorosulfonyl)imide anions (FSI−) and decrease the reduction stability of FSI−. Furthermore, the type of aggregate cluster of FSI− in electrolyte changes, FSI− interacting with more Li ions in the presence of TPFPB. Therefore, the decomposition of FSI− to form Li2S is promoted, improving the stability of anion‐derived SEI. In working Li | LiNi0.5Co0.2Mn0.3O2 batteries under practical conditions, the anion‐derived SEI with TPFPB undergoes 194 cycles compared with 98 cycles of routine anion‐derived SEI. This work inspires a fresh ground to construct stable anion‐derived SEI by manipulating the electrolyte structure of anions.
Directly regulating the electrolyte structure of anions by an anion receptor was proposed for the construction of a stable anion‐derived solid electrolyte interphase (SEI). The introduction of an anion receptor decreases the reduction stability of FSI− and increases the amount of FSI− in the form of AGG‐II. The decomposition of FSI− to form Li2S is promoted, improving the stability of the anion‐derived SEI under practical conditions.
Ammonium (NH4+) ion as charge carrier is attracting attention in aqueous batteries. Yet, most NH4+ host materials are still limited by the relatively low capacities. Here, we fabricated a manganese ...phosphate (MP‐20) for NH4+ ion storage. MP‐20 displays a high capacity of 299.6 mAh g−1 at 1 A g−1 in ammonium acetate (NH4Ac) electrolyte, outperforming other reported NH4+ host materials. Spectroscopy studies suggest a new NH4+/H+ co‐insertion mechanism. We surprisingly discover that the NH4Ac electrolyte plays an important role in improving the charge storage capability of the materials. Experimental and computational results indicate acetate ions can form coordination bonds with the Mn atoms, tailoring the electronic structure of the Mn atoms and the surrounding O atoms, and therefore facilitating the NH4+ storage process. Our findings provide a new NH4+ host material and propose the important role of the electrolyte‐electrode coordination effect in aqueous ammonium batteries.
An amorphous manganese phosphate material is prepared using an electrochemical method for aqueous NH4+ ion storage. The electrode displays an ultra‐high capacity of 299.6 mAh g−1 at a current density of 1 A g−1 in NH4Ac electrolyte. Acetate ions can coordinate with the Mn sites and tailor the surface properties of the electrode, leading to the enhanced NH4+ adsorption capability.
•Recent development in deep learning for monocular depth estimation is reviewed.•Depth estimation is classified into supervised, unsupervised, and semi-supervised methods.•In terms of tasks, depth ...estimation is summarized as single-task and multi-task methods.
Depth estimation is a classic task in computer vision, which is of great significance for many applications such as augmented reality, target tracking and autonomous driving. Traditional monocular depth estimation methods are based on depth cues for depth prediction with strict requirements, e.g. shape-from-focus/ defocus methods require low depth of field on the scenes and images. Recently, a large body of deep learning methods have been proposed and has shown great promise in handling the traditional ill-posed problem. This paper aims to review the state-of-the-art development in deep learning-based monocular depth estimation. We give an overview of published papers between 2014 and 2020 in terms of training manners and task types. We firstly summarize the deep learning models for monocular depth estimation. Secondly, we categorize various deep learning-based methods in monocular depth estimation. Thirdly, we introduce the publicly available dataset and the evaluation metrics. And we also analysis the properties of these methods and compare their performance. Finally, we highlight the challenges in order to inform the future research directions.
Li‐rich Mn‐based layered oxides are regarded as the most promising cathode materials for advanced lithium‐ion batteries with energy density as high as 400 Wh kg−1. However, decline of capacity and ...discharge potential derived from phase transformation during cycling is still an obstacle for practical utilization of Li‐rich cathode materials. Undoubtedly, an in‐depth understanding origin and evolution of the phase transformation from bottom to top is crucial to solve the problem finally. Herein, the recent representative progress on Li‐rich cathode materials from top to bottom is summarized: starting from relationship between dimensions and performance, to evolution of phase transformation, finally to participation of anions during charge–discharge cycling. It systematically shows what happens in the different microscopic levels and how these phenomena relate to cycling of Li‐rich cathode materials with the help of emerging state‐of‐the‐art characterization techniques. On the basis of this progress, it is proposed that rational structural design can fully play its role to build high‐performance energy storage materials and enhance structural stability.
Recent research progress in Li‐rich Mn‐based layered cathode materials are summarized from dimension–performance relationship to evolution of phase transformation, and to participation of anions during cycling, showing systematically what happens in the different microscopic levels and how these phenomena relate with cycling performance.
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