Although the concept of self-healing has undergone a recent resurgence of interest in polymers and other soft materials, it is extremely rare for metal solids to autonomously self-repair structural damage without any external trigger. Here, we report on the direct in situ observation of such an autonomous solid-state self- healing behavior in nanoscale silver (Ag) by utilizing atomic-resolution transmission electron microscopy (TEM). Two representative kinds of structural damage-both nanopores and nanocracks-are observed to undergo automatic self-repair at room temperature and well below (down to 173 K) without any external intervention. Importantly, such an autonomous self-healing phenomenon does not occur in gold (Au) at room temperature, as it is hindered by the stronger Au-Au bonding resulting from the known relativistic effect. A combination of atomistic imaging and molecular dynamics simulation unravels that the self-healing process is accomplished through surface-mediated diffusion of Ag atoms as driven by chemical potential imbalance due to the Gibbs-Thomson effect.

The optical second harmonic generation (SHG) efficiency of hexagonal boron nitride (h-BN) layered materials is profoundly influenced by the symmetry properties, which has severely limited the usefulness of their SHG for nonlinear optical applications. Herein, we report on the controlled growth of large-area and continuous ultrathin h-BN films with a high density of exposed edges that show strongly enhanced SHG, owing to the breaking of inversion symmetry occurring naturally at edge sites. The large-area growth of edge-enriched BN films was accomplished through the introduction of Turing instability into a growth process that involves the liquid-gas interface self-limiting reaction between molten boron oxide (B2O3) with gaseous ammonia (NH3) at elevated temperature. Remarkably, the edge-enriched BN films give rise to a SHG response up to nearly 3 orders of magnitude higher than that of the smooth BN films prepared through the same growth approach but with different growth parameters.

We use an ultrafast optical pump-probe spectroscopy to study quasiparticle (QP) dynamics in a topological insulator LaBi. Temperature-dependent optical measurements have been carried out, by which we observed nearly constant fast component (with a lifetime of 0.15 ps) and slow component (with a lifetime of 1.5 ps) for the whole range from 10 K to 295 K. The laser fluence dependence result shows that there is no saturation for the QP dynamics up to 3.3 mJ /cm2. Moreover, an Eg mode transverse optical (TO) coherent phonon has also been observed, with a frequency of 2.8 THz. Our results provide for the first time the ultrafast dynamics information of both the QPs and coherent phonons in a nodal line topological material.

Recent achievements in semiconductor surface‐enhanced Raman scattering (SERS) substrates have greatly expanded the application of SERS technique in various fields. However, exploring novel ultra‐sensitive semiconductor SERS materials is a high‐priority task. Here, a new semiconductor SERS‐active substrate, Ta 2 O 5 , is developed and an important strategy, the “coupled resonance” effect, is presented, to optimize the SERS performance of semiconductor materials by energy band engineering. The optimized Mo‐doped Ta 2 O 5 substrate exhibits a remarkable SERS sensitivity with an enhancement factor of 2.2 × 10 7 and a very low detection limit of 9 × 10 −9 m for methyl violet (MV) molecules, demonstrating one of the highest sensitivities among those reported for semiconductor SERS substrates. This remarkable enhancement can be attributed to the synergistic resonance enhancement of three components under 532 nm laser excitation: i) MV molecular resonance, ii) photoinduced charge transfer resonance between MV molecules and Ta 2 O 5 nanorods, and iii) electromagnetic enhancement around the “gap” and “tip” of anisotropic Ta 2 O 5 nanorods. Furthermore, it is discovered that the concomitant photoinduced degradation of the probed molecules in the time‐scale of SERS detection is a non‐negligible factor that limits the SERS performance of semiconductors with photocatalytic activity.

Abstract Recent achievements in semiconductor surface‐enhanced Raman scattering (SERS) substrates have greatly expanded the application of SERS technique in various fields. However, exploring novel ultra‐sensitive semiconductor SERS materials is a high‐priority task. Here, a new semiconductor SERS‐active substrate, Ta2O5, is developed and an important strategy, the “coupled resonance” effect, is presented, to optimize the SERS performance of semiconductor materials by energy band engineering. The optimized Mo‐doped Ta2O5 substrate exhibits a remarkable SERS sensitivity with an enhancement factor of 2.2 × 107 and a very low detection limit of 9 × 10−9 m for methyl violet (MV) molecules, demonstrating one of the highest sensitivities among those reported for semiconductor SERS substrates. This remarkable enhancement can be attributed to the synergistic resonance enhancement of three components under 532 nm laser excitation: i) MV molecular resonance, ii) photoinduced charge transfer resonance between MV molecules and Ta2O5 nanorods, and iii) electromagnetic enhancement around the “gap” and “tip” of anisotropic Ta2O5 nanorods. Furthermore, it is discovered that the concomitant photoinduced degradation of the probed molecules in the time‐scale of SERS detection is a non‐negligible factor that limits the SERS performance of semiconductors with photocatalytic activity.

Steady progress has been achieved in the medical genetics in China in 2015, as numerous original researches were published in the world's leading journals. Chinese scientists have made significant contributions to various fields of medical genetics, such as pathogenicity of rare diseases, predisposition of common diseases, somatic mutations of cancer, new technologies and methods, disease-related microRNAs (miRNAs), disease-related long non-coding RNAs (lncRNAs), disease-related competing endogenous RNAs (ceRNAs), disease-related RNA splicing and molecular evolution. In these fields, Chinese scientists have gradually formed the tendency, from common variants to rare variants, from single omic analyses to multipleomics integration analyses, from genetic discovery to functional confirmation, from basic research to clinical application. Meanwhile, the findings of Chinese scientists have been drawn great attentions of international peers. This review aims to provide an overall picture of the front in Chinese medical genetics, and highlights the important findings and their research strategy.