An optimized impedance matching construction strategy: carbon nanofibers inlaid with Ni nanocrystals by electrospinning for high-performance microwave absorber.

With the widespread use of electronic goods, solving electromagnetic pollution has become one of the new challenges. Higher requirements for microwave-absorbing materials (MAM) have emerged to address this issue. The composite of carbon nanofiber (CNF) and magnetic nanoparticles is the material that effectively absorbs microwaves. This paper fabricated Ni/C nanofibers using a combination of electrospinning and high-temperature carbonization. With 50 wt% paraffin wax, Ni/C nanofibers demonstrated optimal microwave absorption capabilities. With a thickness of 3 mm, the minimum RL value can reach -30.6 dB, and the effective absorption bandwidth is 5.96 GHz. By encapsulating Ni nanoparticles in carbon nanofibers, the synergic interaction of dielectric and magnetic losses effectively meets the need for constant attenuation and impedance matching, and effectively improves microwave-absorbing properties. Hence, Ni/C nanofibers are promising for MAM application with excellent MA performance.

The Simulation Design of Microwave Absorption Performance for the Multi-Layered Carbon-Based Nanocomposites Using Intelligent Optimization Algorithm.

The optimal design objectives of the microwave absorbing (MA) materials are high absorption, wide bandwidth, light weight and thin thickness. However, it is difficult for single-layer MA materials to meet all of these requirements. Constructing multi-layer structure absorbing coating is an important means to improve performance of MA materials. The carbon-based nanocomposites are excellent MA materials. In this paper, genetic algorithm (GA) and artificial bee colony algorithm (ABC) are used to optimize the design of multi-layer materials. We selected ten kinds of materials to construct the multi-layer absorbing material and optimize the performance. Two algorithms were applied to optimize the two-layer MA material with a total thickness of 3 mm, and it was found that the optimal bandwidth was 8.12 GHz and reflectivity was -53.4 dB. When three layers of MA material with the same thickness are optimized, the ultra-wide bandwidth was 10.6 GHz and ultra-high reflectivity was -84.86 dB. The bandwidth and reflectivity of the optimized material are better than the single-layer material without optimization. Comparing the GA and the ABC algorithm, the ABC algorithm can obtain the optimal solution in the shortest time and highest efficiency. At present, no such results have been reported.

Application of iron/barium ferrite/carbon-coated iron nanocrystal composites in transcatheter arterial chemoembolization of hepatocellular carcinoma.

Transcatheter arterial chemoembolization (TACE) has been widely used in clinical practice as a first-line treatment for unresectable hepatocellular carcinoma (HCC). However, the current therapeuticeffect of TACE is far from satisfactory and thus requires further improvement. TACE combined with multifunctional magnetic particles may be a promising approach for the treatment of HCC. In this study, we designed a new magnetic drug carrier system consisting of micron-sized iron powder, barium ferrite (BaFe12O19), and carbon-coated iron nanocrystals (CCINs). CCINs possess properties, such as high drug loading and sustained release. BaFe12O19 could attract both CCINs and iron powder to form larger clusters after magnetization. Altogether, the triple therapeutic effects of chemotherapeutic enhancement, embolization, and thermal ablation could be realized herein. Further experiments indicate that the system has a high drug-loading capacity, good controlled-release effect, and no significant cytotoxicity. Under the action of a medium-frequency magnetic induction device, the magnetic induction temperature could reach 43 °C in one min while the maximum temperature of 70.8 °C could be reached in 2.5 h. Overall, this new carrier system displayed excellent antitumor effects in a mouse model. Our findings demonstrate the great application prospects of this system in TACE for HCC.

Ultrafine FeNi3 Nanocrystals Embedded in 3D Honeycomb-Like Carbon Matrix for High-Performance Microwave Absorption.

The reasonable design of magnetic carbon-based composites is of great significance to improving the microwave absorption (MA) performance of the absorber. In this work, ultrafine FeNi3 nanocrystals (5-7 nm) embedded in a 3D honeycomb-like carbon matrix (FeNi3@C) were synthesized via a facile strategy that included a drying and carbonization process. Because of the soft magnetic property of the FeNi3 nanocrystals and their unique 3D honeycomb-like structure, the FeNi3@C composites exhibit excellent MA abilities. When the filler loading ratio of FeNi3@C/paraffin composites is only 30 wt%, the maximum reflection loss (RL) value is -40.6 dB at 10.04 GHz. Meanwhile, an ultra-wide absorption frequency bandwidth of 13.0 GHz (5.0-18.0 GHz over -10 dB) can be obtained in the thickness range of 2.0-4.5 mm, and this means that the absorber can consume 90% of the incident waves. It benefits from the dual loss components, multiple polarizations, and multiple reflections for improving MA performances of FeNi3@C composites. These observations suggest that the 3D honeycomb-like FeNi3@C composites have broad application prospects in exploring new MA materials that have a wide frequency bandwidth and strong absorption.

Investigation on Synthesis, Stability, and Thermal Conductivity Properties of Water-Based SnO2/Reduced Graphene Oxide Nanofluids.

With the rapid development of industry, heat removal and management is a major concern for any technology. Heat transfer plays a critically important role in many sectors of engineering; nowadays utilizing nanofluids is one of the relatively optimized techniques to enhance heat transfer. In the present work, a facile low-temperature solvothermal method was employed to fabricate the SnO2/reduced graphene oxide (rGO) nanocomposite. X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscope (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) have been performed to characterize the SnO2/rGO nanocomposite. Numerous ultrasmall SnO2 nanoparticles with average diameters of 3-5 nm were anchored on the surface of rGO, which contain partial hydrophilic functional groups. Water-based SnO2/rGO nanofluids were prepared with various weight concentrations by using an ultrasonic probe without adding any surfactants. The zeta potential was measured to investigate the stability of the as-prepared nanofluid which exhibited great dispersion stability after quiescence for 60 days. A thermal properties analyzer was employed to measure thermal conductivity of water-based SnO2/rGO nanofluids, and the results showed that the enhancement of thermal conductivity could reach up to 31% at 60 °C under the mass fraction of 0.1 wt %, compared to deionized water.