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This study introduces a new type of shear panel damper that utilizes iron-based shape memory alloy (Fe-SMA) with enhanced low-cycle fatigue (LCF) resistance for structural damage control, with a particular focus on the effect of solution treatment on the properties of interest of Fe-SMA. Material-level investigation was conducted first, aimed at establishing a clear connection between microscopic structure and macroscopic properties, and to determine the most suitable solution treatment method for Fe-SMAs for structural damping purposes. This was followed by laboratory tests on a Fe-SMA based shear panel damper receiving an appropriate solution treatment, along with conventional metal shear panel dampers made of low yield point steel LYP225 and mild steel Q235. Results reveal that among the considered solution treatments, 1,100°C for 1 h leads to the most desired mechanical properties, such as lower yield stress, increased ductility, and longer LCF life, of Fe-SMA for seismic damping applications. The Fe-SMA shear panel damper demonstrates a significant improvement in LCF life and total energy dissipation capacity compared to traditional steel dampers. Finally, detailed numerical investigations were carried out to analyze the seismic response. A calibrated micromechanics-based model, i.e., cyclic void growth model, was employed to predict the fracture initiation of the Fe-SMA shear panel damper under seismic loading. This approach achieved reasonable accuracy, assisting in understanding the distinctive behavior of Fe-SMA shear panel dampers. [ABSTRACT FROM AUTHOR]

We used a meq-deleted attenuated MDV-I strain GX0101Δmeq as a vector to construct a recombinant virus expressing the exogenous gene NDV-F. The ORF of exogenous gene NDV-F was inserted into the eukaryotic expression vector pcDNA3.1(-). Then, the expression cassette of NDV-F which contains the CMV promoter was amplified. Simultaneously, we amplified the selected gene Kan+ expression cassette and inserted them into the PMD18-T vector. Tandem expression cassettes were amplified using primers containing the 50-bp homologous arm of MDV-US2. The PCR product was electroporated into EL250 host bacteria containing GX0101Δmeq. Then, the Kan+ expression cassette was deleted from the recombinant virus genome using 1% arabinose. The plasmid of the positive clone which the Kan+ expression cassette was deleted was extracted and transfected into CEFs to rescue the recombinant virus. The recombinant virus was injected into chickens to observe its growth and replication. The recombinant virus rMDV-F containing the exogenous gene NDV-F was rescued successfully. The recombinant virus could duplicate and express well in CEFs, and grow and replicate well in chickens. Using GX0101Δmeq as a vector, combined with a recombinant system of Red E/T and FLP/FRT, we constructed a recombinant virus that expressed the exogenous gene NDV-F. This study could lay the foundation for further study of recombinant viruses.