Fresh products are perishable and fragile, which easily leads to higher inventory costs and requires reasonable planning of inventory management. Therefore, it is very important for fresh product supply chain systems to have multi-echelon inventory control. However, in past studies, few control models of the multi-echelon inventory considered the deterioration rate of perishable products as the variable factor. In this paper, on the basis of considering the perishable characteristics of fresh products, combining the deterioration rate with the inventory control model, a multi-echelon inventory control model for fresh products is designed and optimized, and the optimal solution from the whole supply chain is obtained through the optimal fitness function by genetic algorithm. Finally, Flexsim is used to simulate the two inventory strategies before and after optimization. After simulation comparison and analysis, it is verified that the optimized inventory control strategy has lower costs. The research results can help supply chain managers of fresh products to make inventory management decisions and save costs, which is of practical significance.

(La1–x–y Er x Yb y )2O2S polyacrylonitrile (LOS-EY/PAN) nanofibers enable the possibility of optical temperature sensing in microregions by introducing a dual temperature feedback fluorescence intensity ratio approach. A ratiometric strategy for the excitation of Er3+ ions by a special upconversion (UC) process is proposed. The green and red UC emissions of Er3+ single doping are confirmed to be unusual three-photon excitation processes attributed to cross-relaxation (CR) of Er3+ ion pairs. When Yb3+ is introduced, the CR process is forced to interrupt and energy is absorbed monopolistically by Yb3+ due to the huge absorption cross section of Yb3+ compared to that of Er3+; therefore, energy transfer from Yb3+ to Er3+ plays a dominant role, and the excitation process is transformed into a conventional two-photon process. With the rearrangement of the excitation mechanism, the overall increase in Er3+ emission is accompanied by an enhancement in the total quantum yield from 8.31 × 10–5 to 1.23 × 10–3. Significant fluorescence sensitization improves the signal-to-noise ratio in practical applications and keeps the relative sensitivity at a high level of 1.29% K–1, further demonstrating the excellent self-feedback nano-temperature sensing function of LOS-EY/PAN fibers promising as a flexible sensing element in fabrics and biomedical devices.