Layered carbides and borides, blending ceramic and metallic characteristics, present compelling prospects for future nuclear reactor applications due to their complex nanolaminate crystal structure. To explore the behavior of Fe 2 AlB 2 under different conditions, helium irradiation is conducted across saturation fluences and under different annealing and irradiation temperatures. Room temperature (RT) irradiation causes some changes: a-lattice expands 0.3 %, c-lattice contracts 0.07 %, and an embedded amorphous layer into the matrix is formed. 400 °C annealing keeps an amorphous structure whereas 800 °C annealing fully recrystallizes with bubble growth. Increasing the irradiation temperature to 400 °C with the same fluence, smaller bubbles form without an amorphous layer, indicating defect recombination depends on helium attachment to vacancies. Under irradiation at 700 °C, faceted bubbles develop exclusively within Fe 2 AlB 2 , with no such bubbles in Al 2 O 3 . These faceted bubbles align themselves along (110) planes. Simultaneously, irradiation prompts tangled dislocations within the damaged layer, fostering the congregation of polygonal bubbles along grain boundaries (GBs) and creating denuded areas at GBs. Fe 2 AlB 2 demonstrates remarkable oxidation resistance under high-temperature irradiation, maintaining surface stability without the cracks seen in ion-irradiated Ti 3 SiC 2 and Ti 2 AlC at RT. Fe 2 AlB 2 shows promise for use in reactors operating at temperatures above 500 °C due to its resilience to irradiation. Further investigation is warranted for its application in reactors operating in environments exceeding this threshold temperature.
Peng Hou,Ke Chen,Xudong Wang,Xiaofei Hu,Bing Li,Ming Liu,Xiao (Matthew) Hu,Yujie Song
The rapid development of high-performance materials has garnered considerable attention in addressing electromagnetic pollution . The construction of core-shell heterostructures is an effective approach for regulating the electromagnetic parameters of absorbers. However, these heterostructures usually lack a direct channel for charge transport between the core phase and the adhesive shell phase. Herein, Fe 2 AlB 2 @FeAl-layered double hydroxides with core-shell heterostructures were prepared using a top-down approach. The tightly connected FeAl-LDHs nanosheets to the Fe 2 AlB 2 parent phase improved electronic transport. Compared with raw Fe 2 AlB 2 , the spherical absorber with an embroidered structure demonstrated stronger reflection loss (-15.6 dB for Fe 2 AlB 2 , −58.6 dB for Fe 2 AlB 2 @FeAl-LDHs) and a broader effective absorption bandwidth (2.2 GHz for Fe 2 AlB 2 , 3.6 GHz for Fe 2 AlB 2 @FeAl-LDHs) due to the enhanced dielectric and magnetic losses. This study presents a practical method for designing new controllable core-shell heterostructures for electromagnetic wave-absorbing materials.
Samaneh Rashtbari,Gholamreza Dehghan,Yasin Orooji,Simin Khataee,Arezu Marefat,Leonid G. Voskressensky,Alireza Khataee
The extensive use of pesticides in modern agriculture has raised concerns about environmental contamination and adverse human health effects. Therefore, developing highly sensitive detection methods to identify pesticide residues is crucial for food safety and ecosystem protection. In this study, the Fe 2 AlB 2 MAX phase was synthesized and characterized. After evaluating its peroxidase-mimetic performance using a colorimetric method, a new, sensitive, and simple dual fluorescence-colorimetric sensor was developed for the quantification of two common pesticides, acetamiprid (ACP) and imidacloprid (IMP), using fluorescein (FL). The developed method is based on the inhibitory impact of ACP and IMP on the enzymatic performance of the Fe 2 AlB 2 MAX phase, specifically the inhibition of hydroxyl radical ( OH) generation, which enhances the absorption and emission intensities of FL. The results confirmed that OH generated through the breakdown of H 2 O 2 via the catalytic activity of the MAX phase can decrease the intrinsic absorption and emission intensities of FL. However, ACP and IMP inhibit the peroxidase-like activity of the MAX phase, leading to increased absorption and emission intensities of FL. The limit of detection values calculated for spectrophotometric and spectrofluorimetric quantifications were 2.8 μM and 0.051 μM for ACP and 1.72 μM and 0.013 μM for IMP, respectively. Furthermore, the proposed method was successfully utilized to accurately and reliably determine ACP and IMP in spiked real samples with satisfactory accuracy and precision. These developed methods offer several advantages, making them promising candidates for the direct, rapid screening of pesticide residues.
危险品化学品经营许可证（带存储）