We propose and experimentally demonstrate a highly sensitive temperature sensor based on cascaded high birefringence fiber loop mirrors (HiBi-FLMs) with the Vernier effect. The two HiBi-FLMs have almost the same free spectrum range (FSR), which can be regarded as two scales of different periods of an optical Vernier-scale, and act as the fixed part and the sliding part, respectively. A Gauss fitting algorithm is introduced to fit the Vernier spectrum envelope to accurately trace the spectral shift of the envelope. The temperature sensitivity and temperature resolution of the cascaded configuration are much larger than those of the individual HiBi-FLMs due to the Vernier effect. The experimental result shows that the temperature sensitivity of the proposed sensor can be improved from − 1.723 n m / ∘ C (single HiBi-FLM) to − 43 n m / ∘ C (cascaded configuration) by employing the Vernier effect, and the temperature resolution is enhanced from ± 0.029 ∘ C to ± 0.001162 ∘ C . The amplification factors for temperature sensitivity and temperature resolution are both 24.96, which shows good agreement with the theoretical predictions. The proposed sensor with huge temperature sensitivity, high resolution, and simple configuration may be a promising candidate for some applications that need precise temperature control.

We present an all-fiber sensor for strain and temperature discrimination by inserting three sections of high birefringence fibers into a Sagnac loop. The principle for strain and temperature discrimination is based on monitoring the wavelength shifts of two different resonant dips that show different sensitivities to temperature and strain. The sensitivities for strain and temperature are measured to be − 0.93 n m / ∘ C and 21 pm/µɛ with discriminative errors of ± 0.3 ∘ C and ± 12 µ ε . The proposed sensor with high sensitivity, simple configuration, and low cost may be a promising candidate for various strain and temperature-sensing applications.

Lithium-ion batteries (LIBs) may experience thermal runaway (TR) under thermal abuse conditions, posing significant safety risks to energy storage systems, electric vehicles, and portable electronics. To ensure the safety of LIB-powered applications, developing an effective TR early warning method is crucial. This study employs polyimide-coated femtosecond fiber Bragg grating (FBG) sensors to investigate TR characteristics in 18,650 LIBs (LiNi_1/3Mn_1/3Co_1/3O₂/graphite), including TR onset temperature determination and the evolution of temperature and radial strain at different states of charge (SOCs). Compared with existing studies, the polyimide-coated femtosecond FBGs employed here offer superior breakage resistance and high-temperature tolerance, enabling more precise temperature and strain measurements. For radial strain monitoring obtained during high-temperature-induced LIBs thermal runaway experiments, temperature compensation was achieved using polyimide-coated femtosecond FBG temperature sensors, yielding higher-accuracy strain evolution profiles. Experimental results demonstrate that the higher-SOC LIBs exhibit more severe TR eruptions, with 1.76× higher peak temperatures and 1.3× greater mass loss than low-SOC LIBs. The proposed scheme pioneers an new approach to effective active safety warning of LIBs thermal runaway.

Current study aims to explore the ameliorative effects of ultrasound in combination with P-selectin-targeted/AM1241-loaded microbubbles (AM1241 MBs) in rats with skeletal muscle ischemia/reperfusion (I/R) injury. AM1241 MB was prepared via rotary evaporation and mechanical shaking. Histological lesions and cellular apoptosis in skeletal muscle were detected by H&E staining and TUNEL staining, respectively. Changes in antioxidant capacity and inflammatory response in skeletal muscle tissue were analyzed by ELISA method. Changes of Nfr2/HO-1 pathway-related proteins were measured via the western blot. As a result, ultrasound-mediated destruction of AM1241 MBs significantly improved the degree of damage and edema in skeletal muscle tissue of rats with I/R injury. Inflammatory response and cellular apoptosis in skeletal muscle tissue were also significantly improved, while the antioxidant capacity was significantly enhanced. Western blot analysis exhibited that ultrasound in combination with AM1241 MBs treatment activated the Nrf2/HO-1 pathway. Nevertheless, selective knockdown of Nrf2 significantly reversed the beneficial effects of ultrasound combined with AM1241 MBs treatment on I/R injuries of the skeletal muscle. Ultrasound-mediated disruption of AM1241 MBs could effectively ameliorate the I/R injuries of skeletal muscle tissues in rats via activating the Nrf2/HO-1 pathway.