Eco-friendly approach for preparation of hybrid silica aerogel via freeze drying method

Journal of Materials Science - In this paper, an eco-friendly method of producing hybrid silica aerogels by freeze-drying method (FD) is proposed. In the freeze-drying system, deionized water was...     

Bimetal-Incorporated Black Phosphorene with Surface Electron Deficiency for Efficient Anti-Reconstruction Water Electrolysis

Surface reconstruction (SRC) is a common phenomenon and a promotion manner for Ni/Co-based precatalysts during the water splitting process. However, the catalytic surface reconstruction will in turn complicate the streamlined prediction and modeling on the catalytic activity. Hence, the rational design of anti-SRC catalysts is highly desirable, but challengeable. In this article, a series of affordable bimetal-incorporated black phosphorene (BP) catalysts are constructed by an in situ electro-exfoliation/insertion method for anti-SRC water electrolysis. It is found that the bimetals (e.g., NiFe, NiPd) are of cationic and covalent incorporation with electron-deficient state in few-layer BP. The optimized bimetal-BP structures present excellent and stable catalytic performances with low overpotentials in hydrogen evolution (HER, 53 mV, NiPd-BP) and oxygen evolution (OER, 268 mV, NiFe-BP) reactions at 10 mA cm⁻² in 1 m KOH. The anti-SRC behaviors are elucidated by in situ Raman studies during HER/OER, probably due to the balanced electron transfer pathway on Ni sites. This research opens interesting possibilities for designing the anti-SRC catalysts for efficient hydrogen production and authentic structure-activity understandings.     

Emerging Nonplanar van der Waals Nanoarchitectures from 2D Allotropes for Optoelectronics

The unique atomic thickness and mechanical flexibility of 2D van der Waals (vdW) materials endow them with spatial designability and constructability. It is easy to break the inherent planar construction through various spatial manipulations, thus creating vdW nanoarchitectures with nonplanar topologies. The basic properties before evolution are retained and tunable by architecture-related feature sizes, and other newly generated properties are inspiring as they are beyond the reach of 2D allotropes, bringing great competitiveness for their encouraging applications in optoelectronics. Here, these representative nonplanar vdW nanoarchitectures (i.e., nanoscrolls, nanotubes, spiral nanopyramids, spiral nanowires, nanoshells, etc.) are summarized and their structural evolution processes are elucidated. Their fascinating nascent properties based on their distinctive structural features, focusing on generally enhanced light–matter interactions and device physics, are further introduced. Finally, their opportunities and challenges for in-depth experimental exploration are prospected. It is a brand-new idea to modify the properties of 2D vdW materials from micro- and nanostructural design and evolution, offering a solid platform for twistronics, valleytronics, and integrated nanophotonics.     

Nb2CTx MXene Derived Polymorphic Nb2O5

Previously, heat treatment was the only feasible route for tuning the crystal phases of niobium pentoxide (Nb₂O₅). With the use of Nb₂CT_x MXene precursors, the first case of phase tuning of Nb₂O₅ in the low-temperature hydrothermal synthesis using sulfuric acid regulating agents is presented. By varying the amount of the agent, four pure-phase Nb₂O₅ crystals and mixed phases in-between are obtained. The required amount is found to be related to the H-covered surface energy calculated based on density functional theory. Overall, MXene-derived B-phase Nb₂O₅ is of particular interest due to its exceptionally high capacities as lithium-ion battery anodes, which are three times higher than the routine synthesized one. Oxygen vacancies induced by crystallographic shear would be responsible for the extraordinary performance. The proposed phase tuning strategy encourages the prudent synthesis of difficult-to-obtain crystal phases.     

Incorporating AR/VR-assisted learning into informal science institutions: A systematic review

Virtual Reality - Virtual reality (VR) and augmented reality (AR) technologies have been used in informal science institutions such as science centres, science museums, zoos, botanical gardens, and...     

Feature selection using max dynamic relevancy and min redundancy

Pattern Analysis and Applications - Feature selection algorithms based on three-way interaction information have been widely studied. However, most of these traditional algorithms only consider...     

Embossed Template Induced Particles Assembly for Heterostructures and the Application in High-Security Encryption

The coassembly of primary particles into heterostructures represents a significant strategy for advanced fabrication of multi-functional materials or devices, and templated assembly has shown remarkable advantage for deterministic placement of particles and the efficient integration with substrates. However, template induced particles coassembly, which is significant for integrating multicomponents at desired positions, is still challenging. Herein, a facile strategy of embossed templateinduced particles coassembly for diverse superstructures and precise patterns is reported. Tunable region selective assembly of particles is demonstrated by controlling the resistance force via designing the embossed edge and surface roughness of the template. Through regulating the template morphologies and particles composition, well-controlled coassembly of “flower” shaped heterostructure and chiral superstructure arrays are realized. Furthermore, the printable nanomaterials self-assembly template is employed to achieve totally bottom-up fabrication of excitation responsive heterostructure arrays, in which the multi-photons process based energy transfer is studied to show the application in high-secure encryption. With the advantage of accurate position and compatible to different materials, this strategy is expected to provide a promising platform for fabricating micro/nanoscale advanced devices.     

Monodispersed Pt Sites Supported on NiFe-LDH from Synchronous Anchoring and Reduction for High Efficiency Overall Water Splitting

Precise design of low-cost, efficient and definite electrocatalysts is the key to sustainable renewable energy. Herein, this work develops a targeted-anchored and subsequent spontaneous-redox strategy to synthesize nickel-iron layered double hydroxide (LDH) nanosheets anchored with monodispersed platinum (Pt) sites (Pt@LDH). Intermediate metal-organic frameworks (MOF)/LDH heterostructure not only provides numerous confine points to guarantee the stability of Pt sites, but also excites the spontaneous reduction for Pt^II. Electronic structure, charge transfer ability and reaction kinetics of Pt@LDH can be effectively facilitated by the monodispersed Pt moieties. As a result, the optimized Pt@LDH that with the 5% ultra-low content Pt exhibits the significant increment in electrochemical water splitting performance in alkaline media, which only afford low overpotentials of 58 mV at 10 mA cm⁻² for hydrogen evolution reaction (HER) and 239 mV at 10 mA cm⁻² for oxygen evolution reaction (OER), respectively. In a real device, Pt@LDH can drive an overall water-splitting at low cell voltage of 1.49 V at 10 mA cm⁻², which can be superior to most reported similar LDH-based catalysts. Moreover, the versatility of the method is extended to other MOF precursors and noble metals for the design of ultrathin LDH supported monodispersed noble metal electrocatalysts promoting research interest in material design.     

核脉冲参数检测系统的FPGA实现

为有效的分析、识别脉冲源特征,本文介绍了基于FPGA的核脉冲参数检测系统的设计。该系统以Ahera CycloneEP1C6Q240C8为核心,以硬件描述语言VerilogHDL表达设计意图,实现了参数检测及串行通信电路的设计。PC端采用图形化编程语言LabVIEW设计下位机软件,显示由RS232传输的参数检测结果。实验结果表明,该系统能有效的实现核脉冲的参数检测,且适用于其他脉冲源的参数检测。