Yanshan University

About: Yanshan University is a education organization based out in Qinhuangdao, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 19544 authors who have published 16904 publications receiving 184378 citations. The organization is also known as: Yānshān dàxué.

Flexible Power Regulation and Current-Limited Control of the Grid-Connected Inverter Under Unbalanced Grid Voltage Faults

Abstract: The grid-connected inverters may experience excessive current stress in case of unbalanced grid voltage fault ride through (FRT), which significantly affects the reliability of the power supply system. In order to solve the problem, the inherent mechanisms of the excessive current phenomenon with the conventional FRT solutions are discussed. The quantitative analysis of three-phase current peak values is conducted and a novel current-limited control strategy is proposed to achieve the flexible active and reactive power regulation and successful FRT in a safe current operation area with the aim of improving the system reliability under grid faults. Finally, the simulation and experiments of traditional and proposed FRT solutions are carried out. The results verify the effectiveness of the proposed method.

Liquid-Exfoliated Black Phosphorous Nanosheet Thin Films for Flexible Resistive Random Access Memory Applications

Abstract: Black phosphorous (BP) is a unique layered p-type semiconducting material. The successful use of BP nanosheets in field-effect transistors fueled research on BP atomic layers that focuses on, e.g., the exploration of their optical and electronic properties, and promising applications in (opto)electronics. However, BP films are prone to degradation in ambient conditions, which prevents their commercial application. Here, a route to the application of BP films as an environmental stable nonvolatile resistive random access memory is presented. The BP films, which are prepared from exfoliated BP nanosheets in selected solvents, show solvent-dependent degradation upon ambient exposure, inducing the formation of an amorphous top degraded layer (TDL). The TDL acts as an insulating barrier just below the Al electrode. This property that was only obtained by degradation, confers a bipolar resistive switching behavior with a high ON/OFF current ratio up to ~3 × 105 and excellent retention ability over 105 s to the flexible BP memory devices. The TDL also prevents propagation of degradation further into the film, ensuring excellent memory performance even after three month of ambient exposure.

Synthesis of urchin-like rutile titania carbon nanocomposites by iron-facilitated phase transformation of MXene for environmental remediation

Abstract: Self-assembling has been confirmed as an effective pathway to achieve some unique properties. The recently developed two-dimensional transition metal carbides (termed MXene) provide more potential opportunities to modify the surfaces of layered materials relative to simple graphene. Here we describe a one-step method for preparing an urchin-like rutile TiO2–C (u-RTC) nano-composite with a high amount of (110) facets by in situ phase transformation of MXene (Ti3C2(OH)0.8F1.2) under FeCl3 conditions. A layered anatase TiO2–C (l-ATC) nano-composite with a high percentage of (001) facets first forms, and then it changes into u-RTC due to the Fe(III) ion induction. The u-RTC displays a high Cr(VI) adsorption capacity of ∼225 mg g−1, which is higher than that of the primitive MXene (∼62 mg g−1) and the l-ATC precursor (∼11 mg g−1), owing to the inhibition of H2O molecule adsorption by bridging oxo groups in terms of the first principles calculations. Apart from the fact that the finding leads to a desirable aligned oxide-carbon material, this approach may set up a new trajectory to self-assemble functional surfaces of other MXene derivatives.