Herein. a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity. Fractional-order calculus has the inherent advantage of easily jumping out of local extreme values; here. it is introduced into the particle-swarm algorithm to invert the true tempera... https://chefesquipmenters.shop/product-category/plumbing-parts/