Vapor Phase Growth of Centimeter-Sized Band Gap Engineered Cesium Lead Halide Perovskite Single-Crystal Thin Films with Color-tunable Stimulated Emission

Single crystal metal halide perovskites thin films are considered to be a promising optical, optoelectronic materials with extraordinary performance due to their low defect densities. However, it is still difficult to achieve large-scale perovskite single-crystal thin films (SCTFs) with tunable bandgap by vapor-phase deposition method. Herein, the synthesis of CsPbCl_3(1–x)Br_3x SCTFs with centimeter size (1 cm × 1 cm) via vapor-phase deposition is reported. The Br composition of CsPbCl_3(1–x)Br_3x SCTFs can be gradually tuned from x = 0 to x = 1, leading the corresponding bandgap to change from 2.29 to 2.91 eV. Additionally, an low-threshold (≈23.9 µJ cm⁻²) amplified spontaneous emission is achieved based on CsPbCl_3(1–x)Br_3x SCTFs at room temperature, and the wavelength is tuned from 432 to 547 nm by varying the Cl/Br ratio. Importantly, the high-quality CsPbCl_3(1–x)Br_3x SCTFs are ideal optical gain medium with high gain up to 1369.8 ± 101.2 cm⁻¹. This study not only provides a versatile method to fabricate high quality CsPbCl_3(1–x)Br_3x SCTFs with different Cl/Br ratio, but also paves the way for further research of color-tunable perovskite lasing.     

Fast medical concept normalization for biomedical literature based on stack and index optimized self-attention

Neural Computing and Applications - Medical concept normalization aims to construct a semantic mapping between mentions and concepts and to uniformly represent mentions that belong to the same...     

Sensitive Detection of Carcinoembryonic Antigen Using Stability‐Limited Few‐Layer Black Phosphorus as an Electron Donor and a Reservoir

The instability of few‐layer black phosphorus (FL‐BP) hampers its further applications. Here, it can be demonstrated that the instability of FL‐BP can also be the advantage for application in biosensor. First, gold nanoparticle/FL‐BP (BP‐Au) hybrid is facilely synthesized by mixing Au precursor with FL‐BP. BP‐Au shows outstanding catalytic activity (K = 1120 s^?1 g^?1) and low activation energy (17.53 kJ mol^?1) for reducing 4‐nitrophenol, which is attributed to the electron‐reservoir and electron‐donor properties of FL‐BP, and synergistic interaction of Au nanoparticles and FL‐BP. Oxidation of FL‐BP after catalytic reaction is further confirmed by transmission electron microscope, X‐ray photoelectron spectroscopy, and zeta potentials. Second, the catalytic activity of BP‐Au can be reversibly switched from “inactive” to “active” upon treatment with antibody and antigen in solution, thus providing a versatile platform for label‐free colorimetric detection of biomarkers. The sensor shows a wide detection range (1 pg mL^?1 to –10 µg mL^?1), high sensitivity (0.20 pg mL^?1), and selectivity for detecting carcinoembryonic antigen (CEA). Finally, the biosensor has been used to detect CEA in colon and breast cancer clinical samples with satisfactory results. Therefore, the instability of BP can also be the advantage for application in detecting cancer biomarker in clinic.     

气相法白炭黑填充天然橡胶的裂纹扩展机理

研究了不同粒径,不同份数的白炭黑对天然橡胶(NR)裂纹生长行为的影响。采用具有裂纹生长测试功能的DMA(DMA-Crack Growth)对预割口试样的裂纹扩展速度进行测试。利用超高速显微摄像技术对裂纹扩展尖端进行在线追踪,得到裂纹扩展尖端的动态显微图像。结果表明,添加20 phr原生粒径为15 nm的气相法白炭黑时,裂纹尖端韧带均匀且细密,对裂纹生长起到很好的阻碍作用;添加20 phr原生粒径为7 nm的气相法白炭黑时,对试样的裂纹生长有不利影响。     

电气检测领域电源稳定性核查方法

产品检测中电源具有十分重要的作用,本文以电动机检测实验室为例,介绍了电器领域中电源稳定性的核查方法。