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The self‐healing capability is highly desirable in semiconductors to develop advanced devices with improved stability and longevity. In this study, the automatic self‐healing in silicon nanowires is reported, which are one of the most important building blocks for high‐performance semiconductor nanodevices. A recovery of fracture strength (10.1%) on fractured silicon nanowires is achieved, which is demonstrated by in situ transmission electron microscopy tensile tests. The self‐healing mechanism and factors governing the self‐healing efficiency are revealed by a combination of atomic‐resolution characterizations and atomistic simulations. Spontaneous rebonding, atomic rearrangement, and van der Waals attraction are responsible for the self‐healing in silicon nanowires. Additionally, the self‐healing efficiency is affected by the fracture surface roughness, the nanowire size, the nanowire orientation, and the passivation of dangling bonds on fracture surfaces. These new findings shed light on the self‐healing mechanism of silicon nanowires and provide new insights into developing high‐lifetime and high‐security semiconductor devices. [ABSTRACT FROM AUTHOR]

SUMMARY: The translocation of photosynthate carbohydrates, such as sucrose, is critical for plant growth and crop yield. Previous studies have revealed that sugar transporters, plasmodesmata and sieve plates act as important controllers in sucrose loading into and unloading from phloem in the vascular system. However, other pivotal steps for the regulation of sucrose movement remain largely elusive. In this study, characterization of two starch excesses in mesophyll (sem) mutants and dye and sucrose export assays were performed to provide insights into the regulatory networks that drive source–sink relations in rice. Map‐based cloning identified two allelic mutations in a gene encoding a GLUCAN SYNTHASE‐LIKE (GSL) protein, thus indicating a role for SEM1 in callose biosynthesis. Subcellular localization in rice showed that SEM1 localized to the plasma membrane. In situ expression analysis and GUS staining showed that SEM1 was mainly expressed in vascular phloem cells. Reduced sucrose transport was found in the sem1‐1/1‐2 mutant, which led to excessive starch accumulation in source leaves and inhibited photosynthesis. Paraffin section and transmission electron microscopy experiments revealed that less‐developed vascular cells (VCs) in sem1‐1/1‐2 potentially disturbed sugar movement. Moreover, dye and sugar trafficking experiments revealed that aberrant VC development was the main reason for the pleiotropic phenotype of sem1‐1/1‐2. In total, efficient sucrose loading into the phloem benefits from an optional number of VCs with a large vacuole that could act as a buffer holding tank for sucrose passing from the vascular bundle sheath. Significance Statement: The mutants identified (starch excess in mesophyll1) hyperaccumulated starch in leaf tissues despite strong sink demand. Cloning and characterization of the gene revealed that it likely plays a primary role in the formation of callose in vascular tissues of leaf and stem. We verified that export of sucrose from leaf tissues in mutants was impaired. Importantly, we initially hypothesized that phloem benefits from an optional number of VCs with a large vacuole that could act as a buffer holding tank for sucrose passing from the vascular bundle. This study could provide new genetic tools to probe source–sink relations in rice, and is thus of interest to photosynthesis research community. [ABSTRACT FROM AUTHOR]

Transition‐Metal chalcogenides have high Li‐ion storage capacity and considerable cycle performance, which has attracted great interest from researchers and is expected to replace graphite materials in the field of Li ion batteries. The purpose of this paper is to find a low‐cost and ecofriendly method for producing copper‐based chalcogenides as anodes with a high capacity and long cycling stability for lithium ion batteries. In our strategy, carbon nanospheres are used as templates to prepare precursor Cu(OH)2@C. Then, the Cu(OH)2@C is converted into copper‐based chalcogenides by different routes. The structure and morphology of the as‐synthesized materials is characterized by the X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. The anode electrochemical performance of the samples was investigated by galvanostatic cycling (GC) vs. Li/Li+ at different current rate. Compared to other copper chalcogenides, the synthesized copper oxide shows better charge/discharge cycle stability and rate performance. Its capacity retention is as high as 128 % at a current density of 0.5 C after 200 cycles. [ABSTRACT FROM AUTHOR]

Compared with the cathode materials, the research on the anode materials of the sodium‐ion batteries has lagged behind. Therefore, development of the anode materials with high capacity, long life, and excellent rate properties is the key to unlocking the practical application for sodium‐ion batteries. This study presents the preparation of hierarchical porous hard carbon as an active anode material from rice husks. The as‐synthesized materials are characterized by X‐ray diffraction, N2 adsorption, Raman spectra, scanning electron microscopy and transmission electron microscopy. These porous hard carbon materials exhibit a high specific surface area and are promising for reversible sodium storage. Galvanostatic studies show that the specific initial capacities of all samples were in the range of 130–300 mA h g−1 at a current density of 100 mA g−1 between 0.01 V and 2.3 V. Compared to the other samples, the hard carbon materials prepared at 800 °C from rice husk (RHPC‐800) can deliver a high reversible capacity of 274 mA h g−1 at a current density of 25 mA g−1, maintain a capacity of approximately 260 mA h g−1, and retain 92.7 % of its capacity after 500 cycles. This excellent electrochemical performance of the as‐prepared RHPC‐800 material is attributed to the high specific surface area and low charge transfer resistance. [ABSTRACT FROM AUTHOR]

Lithium-ion migration at the WO 3 /electrolyte interface is governed by the phase transformation mechanism by which metastable states are replaced from one phase to another. Herein, an in situ single nanowire-based cell is constructed to investigate the dynamic phase transformation and morphology evolution of h-WO 3 nanowire in real-time during its deep lithiation. One of the most significant features of h-WO 3 lithiation is the irreversible transformation from h-WO 3 to Li 2 WO 4. There are a large number of deep ion-trapping sites composed of 4 O atoms in Li 2 WO 4 crystal structure, that is, inserted lithium ions are irreversibly bound in these traps and nearly cannot be deintercalated. A mechanism on irreversible WO 3 -to-Li 2 WO 4 transformation in deep lithiation reaction is demonstrated. With the aid of in situ transmission electron microscopy, we controllably triggered lithium-ion migration at the WO 3 /electrolyte interface and directly visualized the nanoscale lithium-ion migration as a stop motion movie. Hexagonal WO 3 irreversible transformation to Li 2 WO 4 can be experimentally demonstrated via in situ HRTEM in the deep lithiation process including the initial activation of the lithium metal, the wetting of a single WO 3 nanowire and the migration of lithium ions into WO 3 , and the restructuring of hexagonal WO 3. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Novel MnCO3/α-Fe2O3 nanocrystal heterostructures, with MnCO3 nanorods 5–10nm in diameter and 15–50nm in length, grown onto the surfaces of the α-Fe2O3 nanohexahedrons sized around 30–50nm, were fabricated via a two-step solvothermal route. The coalescent planes of the heterostructure for the MnCO3 nanorod and the α-Fe2O3 nanohexahedron were determined to be (01̅4) and (110), respectively. The formation of the MnCO3 nanorods from the Mn contained amorphous flakes was tracked by transmission electron microscopy observations at various reaction stages, which suggested a rolling–broken–growth process. Evidenced by the comparative experimental result, the α-Fe2O3 nanohexahedrons played an important role in inducing the nucleation and growth of the hexagonal MnCO3 nanorods on their surfaces. [Copyright &y& Elsevier]

Sm 2 Co 17 -type permanent magnets have important application value due to their advanced magnetic properties, which can be ascribed to their unique cellular structure and element segregation in various phases developed after isothermal aging treatment. In this study, the evolution of the microstructure combined with the microchemistry of Sm 2 Co 17 -type magnets from solid solution precursor to the cellular structure is investigated, and a new insight into the formation of the cellular structure is provided. We report for the first time that a large number of strip-like nanoscale short-range ordered micro-domains are distributed in the disordered matrix of the solution precursor, which serve as the nucleation centers in the formation of the embryos of the cellular structure. Based on atomic scale structural analyses, a new mechanism concerning the ordering transformation from short-range 2:17R microtwins to long-range 2:17R phase is proposed, involving collective glide of three partial dislocations on successive basal planes with the net Burgers vector to be zero. Furthermore, microchemistry analysis reveals that the segregation of Cu and Fe in the early stage of isothermal aging is accelerated substantially during the ordering transformation, indicating that the ordering transformation can act as a new driving force for element segregation in Sm 2 Co 17 -type magnets. These findings provide new considerations for the development of high performance Sm 2 Co 17 -type magnets. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The realization of chemical diversity of MAX phases is distinctive and important to screen out their unique physiochemical properties for prospective applications. Compared with well-known 25 M-site elements and 23 A-site elements, the option of X-site element is under-explored and restricted in few non-metal elements such as C, N and B. Herein, a chalcogen element selenium was found to be a new member to occupy X site in MAX phases which were stabilized through boron alloying. A series of Zr 2 Se(B 1-x Se x) phases were successfully prepared with occupancy rate x up to 0.97. The crystal structure of these chalcogenide MAX phase was comprehensively characterized and confirmed by Rietveld refinement of X-ray diffraction (XRD), atom-resolved transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. The variation of M 6 X octahedral distortion and the difference in binding energy between Zr 6 Se and Zr 6 B octahedra were found to contribute the phase transformation from boride MAX phase to chalcogenide MAX phase. The effect of occupancy of Se at X site on electrical conductivity of MAX phase was studied and discussed by first-principles calculations, which indicates that the deterioration of carrier motility induced by the strong binding of Zr 6 Se octahedron in MX sublayers leads to the reduction of electrical conductivity. This work also provides a new route to tune the physiochemical properties of MAX phases through the regulation of their basic M 6 X octahedron units. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The novel Co3O4 cubic nanoframes, sized in ca. 30 nm, were firstly fabricated via a facile solvothermal route. Based on the transmission electron microscopy and the powder X-ray diffraction analyses of the time-dependent products, a mechanism of facet-preferential chemical etching of Fe3+ ions to the pre-synthesized Co3O4 nanocubes is proposed for the formation of Co3O4 cubic nanoframes. This synthetic strategy can probably be extended to fabricate nanoframes of some other binary metal oxides, by designing similar chemical etching process. [Copyright &y& Elsevier]