RESUMEN
Fizeau wavelength measurement plays an important role in the fields of laser technology, optical communication, and optical metrology. The accuracy of the traditional multistage Fizeau wavemeter is limited owing to the degradation of the stripe symmetry and finesse caused by variations in the cavity length. Herein, we propose a virtual Fizeau cavity (VFC) based on the principle of phase difference to address this issue. The principle analysis and simulation of this measurement system are presented, along with experiments that verified the feasibility and performance of the VFC method. The wavelength measurement accuracy of this system is superior to 60â MHz in the 350-1100â nm wavelength range. The design concept of "virtual-real combined" cavities first proposed in this paper to our knowledge introduces possibilities for the development of high-accuracy Fizeau wavelength measurements.
RESUMEN
This study examines the effects of different addition levels of tungsten (W) content on the microstructure, corrosion resistance, wear resistance, microhardness, and phase composition of coatings made from FeCoCrNiAl high-entropy alloy (HEA) using the laser cladding technique. Using a preset powder method, FeCoCrNiAlWx (where x represents the molar fraction of W, x = 0.0, 0.2, 0.4, 0.6, 0.8) HEA coatings were cladded onto the surface of 45 steel. The different cladding materials were tested for dry friction by using a reciprocating friction and wear testing machine. Subsequently, the detailed analysis of the microstructure, phase composition, corrosion resistance, wear traces, and hardness characteristics were carried out using a scanning electron microscope (SEM), X-ray diffractometer (XRD), electrochemical workstation, and microhardness tester. The results reveal that as the W content increases, the macro-morphology of the FeCoCrNiAlWx HEA cladding coating deteriorates; the microstructure of the FeCoCrNiAlWx HEA cladding coating, composed of µ phase and face-centered cubic solid solution, undergoes an evolution process from dendritic crystals to cellular crystals. Notably, with the increase in W content, the average microhardness of the cladding coating shows a significant upward trend, with FeCoCrNiAlW0.8 reaching an average hardness of 756.83 HV0.2, which is 2.97 times higher than the 45 steel substrate. At the same time, the friction coefficient of the cladding coating gradually decreases, indicating enhanced wear resistance. Specifically, the friction coefficients of FeCoCrNiAlW0.6 and FeCoCrNiAlW0.8 are similar, approximately 0.527. The friction and wear mechanisms are mainly adhesive and abrasive wear. In a 3.5 wt.% NaCl solution, the increase in W content results in a positive shift in the corrosion potential of the cladding coating. The FeCoCrNiAlW0.8 exhibits a corrosion potential approximately 403 mV higher than that of FeCoCrNiAl. The corrosion current density significantly decreases from 5.43 × 10-6 A/cm2 to 5.26 × 10-9 A/cm2, which suggests a significant enhancement in the corrosion resistance of the cladding coating.
RESUMEN
The prediction model of beef's storage time was established based on multi indexes of fresh beef, such as TVB-N, colony total, pH value, and L* parameter. Visible and near-infrared spectroscopy (Vis/NIR) combined with interval PLS (iPLS)and genetic algorithm(GA) was investigated for establishing PLS calibration model of above 4 indexes, respectively, and rapid and nondestructive prediction of the storage time of fresh beef stored at 4 degrees C was realized. PLS models of 4 indexes were built with full spectrum and effective variables selected by iPLS and iPLS-GA method, respectively. The performance of each model was evaluated according to two correlations coefficients(R) and standard error (SE) of calibration and prediction sets. Experimental results showed that the performance of all models built with effective variable selected by iPLS-GA was better than full spectrum and iPLS. The storage time of calibration and prediction sets of beef samples was predicted by storage time model with predicted values of above 4 indexes, and was achieved as follows: R(c) = 0.903, R(p) = 0.897, SEC = 1.88 and SEP = 2.24. The study demonstrated that the beef's storage time can be synthetically predicted with multi-index by using visible and near-infrared spectroscopy combined with the prediction model of beef's storage time. This provides a new method for rapid and nondestructive detection of beef's storage time or shelf life.