Magnetic–dielectric composites are usually designed to develop high-performance microwave absorbers. In this paper, magnetic–dielectric Ti
3
SiC
2
/Co
2
Z ferrite composites were firstly prepared for ...application in microwave-absorbing materials. The phase structure, micro-morphology, electromagnetic response behavior, and microwave absorption performance of these composites have been investigated and subsequently discussed. The measured results showed that the introduction of dielectric Ti
3
SiC
2
into magnetic Co
2
Z ferrite can increase the complex permittivity and dielectric loss of these composites appropriately. And then, a desired stronger reflection loss peak of –38.04 dB could be achieved with a thin thickness of 1.5 mm in the Ti
3
SiC
2
/Co
2
Z composite-filled microwave-absorbing materials. It was also found that appropriately increasing the complex permittivity can improve the electromagnetic attenuation ability and the impedance-matching property simultaneously, which eventually contributes to the enhanced microwave absorption performance.
Aim to blemish of total least square algorithm based on error equation of virtual observation,this paper
proposed a sort of improved algorithm which doesn’t neglect condition equation of virtual ...observation,and considers both
error equation and condition equation of virtual observation.So,the improved algorithm is better.Finally,this paper has
fitted a straight line in three-dimensional space based on the improved algorithm.The result showed that the improved
algorithm is viable and valid.
The main strengthening mechanism in Al-Li alloys is generally achieved by the existence of a high volume fraction of the L12-Al3Li precipitation from Al matrix. In this work, we do density functional ...theory (DFT) total energy calculations on the site occupancy behaviour of transition metals in L12-Al3Li compound. The ground state properties of L12-Al3Li, fcc-Al, and bcc-Li are determined and compared to the available literature data. The formation energies of intrinsic point defects in L12-Al3Li phase as well as Al3LiX alloy formation energy are calculated and identified. We show that the Li antisite is preferential to from in the L12-Al3Li phase. Finally, the site occupancy behaviour of transition metals in L12-Al3Li as well as the solute atomic volume effect on the solute site preference and lattice expansion of the L12-Al3Li have been studied, the later results can be used for an indirect estimation of the site substitution behaviour of the alloying elements in L12-Al3Li phase.
We experimentally demonstrate an optical transportation and controllable positioning of polystyrene nanospheres using a 3 μm diameter microfiber. By placing the microfiber in a microfluidic channel ...and injecting a 980 nm laser light into the fiber, nanospheres suspended in the water were stably trapped to the microfiber and delivered along the direction of light propagation. Furthermore, by increasing the velocity of the fluid in the opposite direction of the laser light, it was found that, once the fluid velocity increased to 6 μm/s, spheres stopped their forward progress and halted on the microfiber, so the controllable positioning of spheres along the microfiber was realized.
•Magnetic FeNi alloy-decorated Ti3C2Tx MXene were successfully prepared.•Improved magnetic loss and impedance matching can be observed in the FeNi/Ti3C2Tx MXene composites.•A broad effective ...bandwidth of 6.2 GHz was achieved in the FeNi/Ti3C2Tx MXene composites with the thickness of 1.6 mm.
MXene-based magnetic–dielectric composites with synergetic magnetic and dielectric losses have exhibited great potential in the practical applications of microwave absorbing material. In the present paper, novel composites consisting of laminated Ti3C2Tx MXene decorated with magnetic FeNi nanoparticles were constructed via a facile in situ hydrothermal approach. The microstructure, morphology, magnetic properties, and microwave absorption performances of as-synthesized samples were investigated in detail, and corresponding mechanisms were further discussed. Results demonstrated that the frequency dependence of electromagnetic parameters for the FeNi/Ti3C2Tx MXene composites could be easily regulated by simply changing the content of FeNi nanoparticles in favor of improved magnetic loss and optimized impedance matching. Consequently, a broadband effective absorption bandwidth (RL < − 10 dB) of 6.2 GHz with a thin matched thickness of 1.6 mm was achieved for the FeNi/Ti3C2Tx MXene composites with 20 wt% FeNi loading, which could be identified as high-efficiency microwave absorbing material.
•Black LiTaO3 wafers were produced using a simple reduction process.•A novel reduction agent was found for the preparation of black LiTaO3 wafers.•The blackening mechanism are attributed to both TaC ...and O vacancies in the wafers.•The resistivity and light transmission efficiency of LiTaO3 wafers are well controlled.
Tantalum lithium (LiTaO3) is known as a “universal” material in the field of functional materials. However, due to its high pyroelectric coefficient and transmission efficiency, practical applications are limited. In this study, black LiTaO3 wafer was prepared by a simple reduction process by using a new reductant composed of FeSiAl flaks, C nanoparticles, and Fe-C core–shell nanoparticles. It was found that the as-prepared wafers have tunable light transmission efficiency and resistance. Moreover, it was also found that the annealing temperature of 800 °C is the threshold temperature of the wafer in the reduction process. Furthermore, it was revealed that the underlying blacking mechanism could be attributed to the wafers' generation of TaC and O vacancies during the reduction process. This work presents a simple method to blackening, uncovers a novel mechanism, and provides tunable light and resistivity transmission efficiency of LiTaO3, which may serve as benchmarks for related studies and promote LiTaO3′s practical applicability.
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•This paper reveals the formation mechanism of AgNi nanoparticles from the perspective of surface diffusion and the physical causes of the clustering of surface atoms into islands ...during growth.•Among all the surface exchange diffusion paths defined in this study, the center exchange diffusion paths, especially CPDE, are the best when the system energy decreases after the substrate boundary atom is exchanged with an adatom.•The relative magnitude of the exchange energy barriers between hetero adsorbed atoms and atoms on the substrate surface is a major determinant of the formation of core–shell and three-layer onion-like structures and the degree of surface alloying of the nanoparticles.•In addition, the appearance of surface energy trap sites during the growth of AgShellNi Core nanoparticles leads to the diffusion of surface Ag atoms to these sites and their aggregation into Ag islands.
Quantifying the kinetic processes of the diffusion and growth of adsorbed atoms on the surface of nanoparticles at the atomic level enables the control of nanomaterial structures. To examine the diffusion and growth of adsorbed atoms on the surface of nanoparticles, this study adopts AgNi nanoparticles as an example, comprehensively explores surface diffusion, and reveals the physical causes of the growth results from the perspective of surface diffusion. Molecular dynamics, Monte Carlo, and nudged elastic band methods are utilized. Many studies have been conducted on the diffusion barriers of adsorbed atoms. On the basis of these studies, the current work classifies the diffusion paths of adsorbed atoms on the surface of nanoparticles in detail and determines the optimal surface diffusion paths. It reveals the formation mechanism of AgNi nanoparticles from the perspective of surface diffusion and the physical causes of the clustering of surface atoms into islands during growth. Among all the surface exchange diffusion paths defined in this study, the center exchange diffusion paths, especially CPDE, are the best when the system energy decreases after the substrate boundary atom is exchanged with an adatom. The relative magnitude of the exchange energy barriers between hetero adsorbed atoms and atoms on the substrate surface is a major determinant of the formation of core–shell and three-layer onion-like structures and the degree of surface alloying of the nanoparticles. In addition, the appearance of surface energy trap sites during the growth of AgShellNiCore nanoparticles leads to the diffusion of surface Ag atoms to these sites and their aggregation into Ag islands.
The Publisher and Editor have retracted this article 1 in accordance with good ethical practices. After a thorough investigations
we believe that the peer review process was compromised. The article ...was published on-line on
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