The magnetostrictive microcantilever (MSMC) as a high-performance transducer was introduced for the development of biosensors. The principle and characterization of MSMC are presented. The MSMC is wireless and can be easily actuated and sensed using magnetic field/signal. More importantly, the MSMC exhibits a high Q value and works well in liquid. The resonance behavior of MSMC is characterized in air at different pressures and in different liquids, respectively. It is found that the Q value of the MSMC in water reaches about 40. Although the density and viscosity of the surrounding media affect the resonance frequency and the Q value of MSMC, the density has a stronger influence on the resonance frequency and the viscosity has a stronger influence on the Q value, which result in that, for MSMC in air at pressure of less than 100 Pa, the resonance frequency of MSMC is almost independent of the pressure, while the Q value increases with decreasing pressure. MSMC array was developed and characterized. It is experimentally demonstrated that the characterization of an MSMC array is as simple as the characterization of a single MSMC. A filamentous phage against Salmonella typhimurium was utilized as bio-recognition unit to develop an MSMC based biosensor. The detection of S. typhimurium in water demonstrated that the MSMC works well in liquid.
To realize the effective recycling of solid waste fly ash (FA) and reduce the preparation cost of microwave absorbent, the Fe-loaded fly ash composites (FeFA) were synthesized using FA. In this study, the FeFA composites were prepared through granulation technology with FA, impregnation with Fe 3+ , and the carbothermal reduction process under different annealing temperatures, during which the Fe particles as main magnetic components were uniformly embedded into the interior and surface of the ceramic matrix. As expected, the FeFA800 composite showed superior microwave absorption (MA) performance, its minimum reflection loss (RL min ) value could reach −40.3 dB when the coating thickness was 2.5 mm and the effective bandwidth reached 4.1 GHz with the coating thickness of 1.5 mm. The attenuation of electromagnetic wave should benefit from the effective impedance matching characteristics and multiple interfacial polarization effects between the different components in the composite. Owing to the facile preparation process, excellent MA performance, and low cost, the FeFA composites with a density of 1.69−1.91 g/cm 3 can be a promising candidate for application in the field of electromagnetic wave absorption and shielding. This work also opens up a way for the comprehensive recovery and utilization of FA.
Latent curing agent is significantly important to develop one-component epoxy resins. However, the reported latent curing agents are from unsustainable fossil resources. Herein, a new type of latent curing agent—amino...
The influence of a commercial coupling agent on the dielectric properties and microstructure of ceramic-polymer nanocomposites are studied. Free-standing BaTiO3-P(VDF-CTFE) films were fabricated using a simple solution-casting process, and the good wettability between fillers and polymer matrix was obtained by using 3-Aminopropyltriethoxysilane as coupling agent. It is found that the coating of a small amount of coupling agent on the surface of BaTiO3 fillers results in an enhanced dielectric constant, a higher breakdown strength and a larger energy-storage efficiency. When an excessive amount of coupling agent was used, the non-attached coupling agent molecules participated in the complex reactions and result in the aggregation of fillers and the reduction of dielectric constant. It is also found that the surface modification of fillers has a complicated influence on its dielectric behavior which leads to an increase in the dielectric loss of the nanocomposites. When an appropriate amount of coupling agent is coated on fillers, the energy storage density of the nanocomposite is improved due to the enhanced dielectric constant and higher breakdown strength. A maximal discharged energy-storage density of about 4.0 J cm−3 was obtained from the nanocomposite film containing 15 vol% of surface modified BaTiO3 fillers with 1 wt% of KH550, which is about 3 times of that for the nanocomposite without coupling agent.
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