Search

A simple synthetic method of poly(hexamethylene guanidine hydrochloride) grafted hollow nano-silica (HSN-PHMG), a novel antibacterial material, was proposed. The water dispersibility and antibacterial property of HSN grafting of PHMG were improved. The hollow structure of nano-silica was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis were used to characterize the successful grafting of PHMG and the mass fraction of PHMG is about 9.5% in HSN-PHMG. Antibacterial test using Escherichia coil (E.coil) and Staphylococcus aureus (S.aureus) as test strains and the results show that the minimum inhibitory concentration (MIC) of HSN-PHMG on E.coil and S.aureus are all 32 mg/L; E.coil can be completely killed within 2 h when the concentration of HSN-PHMG is 64 mg/L.

A simple synthetic method of poly(hexamethylene guanidine hydrochloride) grafted hollow nano-silica (HSN-PHMG), a novel antibacterial material, was proposed. The water dispersibility and antibacterial property of HSN grafting of PHMG were improved. The hollow structure of nano-silica was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis were used to characterize the successful grafting of PHMG and the mass fraction of PHMG is about 9.5% in HSN-PHMG. Antibacterial test using Escherichia coil (E.coil) and Staphylococcus aureus (S.aureus) as test strains and the results show that the minimum inhibitory concentration (MIC) of HSN-PHMG on E.coil and S.aureus are all 32 mg/L; E.coil can be completely killed within 2 h when the concentration of HSN-PHMG is 64 mg/L.

Investigation of absolute instability (AI) and convective instability (CI) of the electron cyclotron maser has independently led to the birth of gyrotron oscillators and amplifiers. Here, it is demonstrated that these instabilities can form a cooperative relationship owing to the nonlinear behavior of the stimulated electron beam. The CI can be induced in a zero‐drive system with the assistance of AI, and the ohmic losses of all the excited waves inside the system are greatly reduced, which is called "instability entanglement" here. According to the theoretical and experimental study of a 167/330 GHz gyrotron, when instability entanglement occurs, the ohmic dissipation decreases to one‐ninth of the AI‐only condition, and the output power is enhanced by 20%. This discovery is promising for surpassing the ceiling of output power and frequency of gyrodevices placed by ohmic losses. [ABSTRACT FROM AUTHOR]

The rapid rise of two-dimensional (2D) materials has aroused increasing interest in the fields of microelectronics and optoelectronics; various types of 2D van der Waals heterostructures (vdWHs), especially those based on MoS2, have been widely investigated in theory and experiment. However, the interfacial properties of MoS2 and the uncommon crystal surface of traditional three-dimensional (3D) metals are yet to be explored. In this paper, we studied heterostructures composed of MoS2 and metal(001) slabs, based on the first-principles calculations, and we uncovered that MoS2/Au(001) and MoS2/Ag(001) vdWHs reveal Schottky contacts, and MoS2/Cu(001) belongs to Ohmic contact and possesses ultrahigh electron tunneling probability at the equilibrium distance. Thus, the MoS2/Cu(001) heterostructure exhibits the best contact performance. Further investigations demonstrate that external longitudinal strain can modulate interfacial contact to engineer the Schottky–Ohmic contact transition and regulate interfacial charge transport. We believe that it is a general strategy to exploit longitudinal strain to improve interfacial contact performance to design and fabricate a multifunctional MoS2-based electronic device. [ABSTRACT FROM AUTHOR]

Recent advances in vortex Smith–Purcell radiation (V‐SPR) have spurred many breakthroughs in the generation of vortex beams for their potential applications in chiral detection, particle acceleration, communication, and imaging. However, advanced multi‐mode applications of the V‐SPR suffer from the incoherent spectrum and poor purity in producing high‐order topological charges. Here, by exploiting the rotational symmetry and Brillouin‐folding phenomenon, it is proved that the coherent V‐SPR with independently steerable high‐order topological charge is directly emitted from chiral spoof surface plasmons. Moreover, both topological charges and operation frequencies can be readily tuned, thus enabling flexible adaptability over a broad bandwidth. A proof‐of‐concept prototype is designed and fabricated in the microwave regime, in which the method is demonstrated from the perspective of symmetry and tunability. The proposed methodology can be exploited as a platform to investigate the interaction between chiral plasmons and swift electrons, promising a feasible scheme for generating coherent and tunable vortex beams from the microwave to the terahertz band. [ABSTRACT FROM AUTHOR]