Improving brittle behavior and mechanical properties is still a big challenge for high-temperature structural materials. By means of first-principles calculations, in this paper, we systematically investigate the effect of vacancy and oxygen occupation on the elastic properties and brittle-or-ductile behavior on Mo5Si3. Four vacancies (Si–Va1, Si–Va2, Mo–Va1, Mo–Va2) and oxygen occupation models (O–Mo1, O–Mo2, O–Si1, O–Si2) are selected for research. It is found that Mo–Va2 vacancy has the stronger structural stability in the ground state in comparison with other vacancies. Besides, the deformation resistance and hardness of the parent Mo5Si3 are weakened due to the introduction of different vacancy defects and oxygen occupation. The ratio of B/G indicates that oxygen atoms occupation and vacancy defects result in brittle-to-ductile transition for Mo5Si3. These vacancies and the oxygen atoms occupation change the localized hybridization between Mo–Si and Mo–Mo atoms. The weaker O–Mo bond is a contributing factor for the excellent ductile behavior in the O-Si2 model for Mo5Si3.

The vacancy defects and oxygen atoms occupation effects on mechanical and electronic properties of Mo5Si3 silicides

The sustainable growth of any society is in direct proportion with developing novel methods and technologies for the management of its environmental quality. The use of Magnetic Nanoparticles (MNPs) has emerged as an efficient tool for remediation of wastewater owing to its intrinsic qualities including size, surface effect, quantum effect, etc. These intrinsic properties of MNPs have diversified their application in managing the qualitative stress on water resources. The present review aims to assess the use of MNPs in removing organic and inorganic contaminants from wastewater. Insights into various synthesis methods and their effects on contaminant removal are also presented. It is reported that MNPs provide target specificity and cost-effectiveness as compared to conventional treatment methods. Moreover, the biological synthesis of MNPs is proven to be eco-friendly and aids in sustainable development. Nearly 100% removal of various types of contaminants such as pharmaceuticals and personal care products, dyes, pesticides, heavy metals, etc. can be achieved through MNPs. Some MNPs have shown a magnetic saturation reaching up to 70 emu/g, and recycling up to 5 cycles with >95% removal efficiency. High pollutant removal efficiency (>98%) can also be achieved in a short time (within 5 min) by MNPs. It is noteworthy that, nanosorption along with the redox reactions are the most frequently used and efficient mechanisms of contaminant removal from wastewater samples.

Synthesis and characterization of magnetic nanoparticles, and their applications in wastewater treatment: A review

The magnetic behaviors and magnetocaloric effect of a nano-graphene bilayer: A Monte Carlo study

We applied Monte Carlo simulation to investigate the thermodynamic properties and hysteresis loops of the hexagonal core-shell nanoparticle described by a ferrimagnetic mixed-spin (3/2, 5/2) Ising model. The results revealed the significance of the single-ion anisotropy, exchange coupling, external magnetic field in dominating various thermodynamic quantities and hysteresis loops. We obtained the variation of the critical temperature with various parameters. Under certain parameter conditions, the system may exhibit rich multiple-loop hysteresis behaviors, depending on the competition among the physical parameters.

Thermodynamic properties and hysteresis loops in a hexagonal core-shell nanoparticle.

Study on the dynamic magnetic behaviors in a ferrimagnetic mixed spin Ising ladder-type graphene nanoribbon

Using Monte Carlo simulation, we investigated magnetic and thermodynamic characteristics of the rectangle core–shell ferrimagnetic mixed-spin (3/2, 2) Ising nanoribbon under the effects of sublattice crystal field, exchange coupling and temperature. Typical temperature dependence of the total magnetization, the core and shell magnetization, the susceptibility and the internal energy for several fixed values of Hamiltonian parameters were discussed in detail. The phase diagrams of the critical and compensation temperatures were presented in various Hamiltonian parameter planes. In addition, particular emphasis was given to the interesting multi-cycle hysteresis behaviors of the total system and sublattices. Our results show reasonable consistency compared with many previous theoretical and experimental studies.

Magnetic and thermodynamic characteristics of a rectangle Ising nanoribbon

Dielectric properties of an antiferroelectric/ferroelectric BiFeO3/Co bilayer structure

The magnetic properties and magnetocaloric effect of an antiferromagnetic/ferromagnetic (AFM/FM) BiFeO3/Co bilayer with mixed-spin (5/2, 3/2) have been studied based on Monte Carlo simulation. The magnetization, susceptibility, and critical temperature are investigated under various exchange couplings and an external magnetic field. In particular, the influence of exchange couplings and an external magnetic field on the magnetic entropy change, adiabatic temperature change, and the relative cooling power (RCP) are studied. The simulation results indicated that the decrease of the exchange coupling and the increase of external magnetic fields can cause an increase of magnetic entropy change, adiabatic temperature change, and RCP. In addition, the hysteresis loops of the system are presented for different exchange couplings and temperatures.

Monte Carlo study of the magnetic properties and magnetocaloric effect of an AFM/FM BiFeO3/Co bilayer

Wearable smart devices have gradually become the development trend, and it calls for functionalized flexible batteries. The development of suitable electrode materials is one of the key parts to meet the electrochemical requirements, as well as light weight, good mechanical properties and high energy density. However, severer volume expansion occurs after repeated intercalation/deintercalation of large-radius K ions, making the development of flexible potassium-ion batteries (PIBs) more challenging. To realize low-cost, high-safety and more practical flexible PIBs, more efforts are needed in the exploration of electrode materials. In this review, we summarize the research progress of all the reported flexible PIBs till now, focus on the research results of flexible electrode materials with different dimensions in the aspects of structural design, manufacturing process and electrochemical performance. Finally, we analyze and discuss the key challenges faced by flexible electrode materials of PIBs, and provide the prospects to the practical use of low-cost flexible PIBs in smart devices. 

Han Huang

Papers

Magnetic and thermodynamic characteristics of a rectangle Ising nanoribbon

Dielectric properties of an antiferroelectric/ferroelectric BiFeO3/Co bilayer structure

Thermodynamic properties and hysteresis loops in a hexagonal core-shell nanoparticle.

Monte Carlo study of the magnetic properties and magnetocaloric effect of an AFM/FM BiFeO3/Co bilayer

Development of electrode materials for flexible potassium-ion batteries