Optical fiber sensors based on refractive index modulation are befitting the in-situ monitoring of seawater salinity. However, most existing fiber-optic sensors only focus on measurement resolution and range, but rarely consider the impact of temperature crosstalk. Thus, a novel salinity sensor with temperature self-compensation is proposed, which is composed of the hollow core fiber (HCF) micro-filled with a short section of polydimethylsiloxane, it simultaneously excites Fabry-Perot interference and anti-resonant effects. Seawater flows into the interior of HCF through micro-defects on fibers, which not only solves the problem of the inability to excite the anti-resonant phenomenon of HCF under liquid immersion condition, but also realizes salinity measurement with the sensitivity of -0.961 nm/‰. In addition, the temperature crosstalk during the salinity sensing process is compensated by the PDMS-based Fabry-Perot interferometer, and the measurement error is reduced. The seawater salinity sensor demonstrated here has the advantages of compact structure, robustness, and high reproducibility, which provides key technical support for optical sensing applied in the ocean and has broad application potential in microfluidic sensing.

A methoxy poly(ethylene glycol) (MePEG)-conjugated linoleic acid (CLA) polymeric conjugate is synthesized with the use of dicyclohexycarbodiimide and 4-dimethylaminopyridine as the coupling agent and the catalyst, respectively. Self-assembled MePEG-CLA conjugate micelles are prepared by dialysis in water. Fluorescence spectroscopy indicates that the MePEG-CLA conjugate exhibits a typical core-shell micellar structure, and the estimated critical micelle concentration is 1.2 × 10⁻⁵ mol L⁻¹. Dynamic light scattering and transmission electron microscopy demonstrate that the prepared MePEG-CLA micelles have spherical shape and an average diameter of approximately 100 nm. Paclitaxel is entrapped into MePEG-CLA lyophilized powder. The release of paclitaxel from the loaded micelles is investigated in vitro. A biphasic release pattern with a fast release rate followed by a slow release is observed.

A four-loop shaped structure of fiber Bragg grating (FBG) acoustic emission (AE) sensor based on additive manufacturing (AM) technology is proposed in the letter. The finite element analysis (FEA) method was used to model and analyze the sensor structure. We aimed at improving the sensitivity, the static load analysis, and the dynamic response analysis of the normal FBG acoustic emission sensor and the FBG AE sensor with improved structure parameters. We constructed the FBG AE sensor experimental system based on a narrowband laser demodulation method and test on real acoustic emission signals. The results demonstrated that the response sensitivity of the FBG acoustic emission sensor was 1.47 times higher than the sensitivity of the normal FBG sensor. The sensitivity coefficient of PLA-AE-FBG2 sensor was 3.057, and that of PLA-AE-FBG1 was 2.0702. Through structural design and parameter optimization, the sensitivity and stability of the FBG AE sensor are improved. The four-loop shaped sensor is more suitable for the health monitoring in fields such as aero-engine blade, micro-crack of structure, and crack growth in bonded joints. While ensuring the sensing characteristics, sensitivity, and stability of the four-loop shaped sensor have been enhanced. It is possible to apply the FBG AE sensor in some complex engineering environments.