A New Method for Moving-Target HRRP via Double Step Frequency Verified by Simulation.

The stepped-frequency (SF) waveform is highly sensitive to the target motion, which induces range shift and echo spread in a high-range-resolution profile (HRRP). This paper proposes a method based on a cross-transmitted double-stepped frequency (DSF) waveform and the phase-cancellation technique. The proposed method obtains the stationary HRRP of the moving targets according to the inverse discrete Fourier transform (IDFT) and complex multiplication. The results also show that the proposed method eliminates the generated false peaks from the existing methods. As a result, the obtained signal-to-noise ratio (SNR) of the HRRP using the proposed method is improved. Due to the cross-transmitted DSF waveform application, the proposed method adapts to higher speed targets. The analysis and simulation results validate the effectiveness of the proposed approach.

Thiol-Assisted Synthesis of Carbon-Supported Metal Nanoparticles for Efficient Electrocatalytic CO2 Reduction.

The typical preparation route of carbon-supported metallic catalyst is complex and uneconomical. Herein, we reported a thiol-assisted one-pot method by using 3-mercaptopropionic acid (MPA) to synthesize carbon-supported metal nanoparticles catalysts for efficient electrocatalytic reduction of carbon dioxide (CO2 RR). We found that the synthesized Au-MPA/C catalyst achieves a maximum CO faradaic efficiency (FE) of 96.2% with its partial current density of -11.4 mA/cm2 , which is much higher than that over Au foil or MPA-free carbon-supported Au (Au/C). The performance improvement in CO2 RR over the catalyst is probably derived from the good dispersion of Au nanoparticles and the surface modification of the catalyst caused by the specific interaction between Au nanoparticles and MPA. This thiol-assisted method can be also extended to synthesize Ag-MPA/C with enhanced CO2 RR performance.

Fast and Universal Solution-Phase Flocculation Strategy for Scalable Synthesis of Various Few-Layered MXene Powders.

MXenes have gained great attention in various fields because of their fascinating properties; however, the preparation of few-layered MXene powders is still limited by serious restacking of MXene nanosheets. Herein, for the first time, we have demonstrated an effective ammonium ion route to fundamentally address restacking and aggregation of the MXene nanosheets, using a solution-phase flocculation method (NH4+ method and modified NH4+ method) for large-scale preparation of few-layered Ti3C2Tx MXene powders in large quantities. The as-prepared few-layered MXene nanosheet powders show large size in the ab plane without the restacking phenomenon even at scanning electron microscopy measurements of 400× magnification, demonstrating the effectiveness of the proposed method. The method is also suitable for large-scale synthesis of other few-layered MXene powders, including Nb4C3Tx, V2CTx, Nb2CTx, etc., providing a general approach for the preparation of various few-layered MXene nanosheet powders, which represents a significant result for the development of MXenes.

Rational Design of Porous N-Ti3C2 MXene@CNT Microspheres for High Cycling Stability in Li-S Battery.

Herein, N-Ti3C2@CNT microspheres are successfully synthesized by the simple spray drying method. In the preparation process, HCl-treated melamine (HTM) is selected as the sources of carbon and nitrogen. It not only realizes in situ growth of CNTs on the surface of MXene nanosheets with the catalysis of Ni, but also introduces efficient N-doping in both MXene and CNTs. Within the microsphere, MXene nanosheets interconnect with CNTs to form porous and conductive network. In addition, N-doped MXene and CNTs can provide strong chemical immobilization for polysulfides and effectively entrap them within the porous microspheres. Above-mentioned merits enable N-Ti3C2@CNT microspheres to be ideal sulfur host. When used in lithium-sulfur (Li-S) battery, the N-Ti3C2@CNT microspheres/S cathode delivers initial specific capacity of 927 mAh g-1 at 1 C and retains high capacity of 775 mAh g-1 after 1000 cycles with extremely low fading rate (FR) of 0.016% per cycle. Furthermore, the cathode still shows high cycling stability at high C-rate of 4 C (capacity of 647 mAh g-1 after 650 cycles, FR 0.027%) and high sulfur loading of 3 and 6 mg cm-2 for Li-S batteries.

Velvet antler polypeptide is able to induce differentiation of neural stem cells towards neurons in vitro.

OBJECTIVE: To investigate the neural differentiation capacity of water extraction of velvet antler. METHODS: Velvet antler (Cervus Nippon Temminck) polypeptide (VAP) was used to differentiate neural stem cells (NSCs) towards neurons in the study. Firstly, we obtain the polypeptides of VAP by water extraction. Secondly, we observed the morphology, assayed the factors in the media by enzyme-linked immunosorbent assay, and detected the special neural molecules by immunfluorescence staining. NSCs were cultured on the cell climbing film. After neuronal differentiation, differentiated NSCs were mounted for immunocytochemistry with immunofluorescence technique. RESULTS: The differentiating cells look like neuron, some special factors, such as Glial cell line-derived neurotrophic factor, nerve growth factor, in the media can be detected while differentiated neuron-like cells can express the special neural molecules. CONCLUSION: Differentiation of NSCs towards neurons can be induced by velvet antler polypeptide.