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In this paper, we present a method of solving the chromatic aberration problem of large spectral bandwidth optical systems encountered during the internal focusing process. Rational selection of the focal length of each lens group and the distance between them retained the achromatic characteristic of the optical system when the inner focus lens group was mobilized. The proposed design was experimentally validated. This paper can be useful to research on internal focusing in wide-band systems.We investigate an all-metal and simple-fabrication grating with an ultranarrow band absorption spectrum in the telecom window range. The influences of structure parameters on the absorption characteristics are investigated. For the best design, the absorption efficiency reaches 94% under normal incidence, with the full width at half-maximum of only 0.17 nm. We demonstrate that this ultranarrow band absorption is the result of the dominant excitation of the Rayleigh anomaly mode. The corresponding figure of merit is calculated to be 8530RIU-1. The applied procedure has the potential to also be used in designing high-performance reflection-based sensors in other wavelength ranges.We present a novel static W-shaped common-path interferometer. In particular, the W-shaped common-path corner-cube retroreflector interferometer (W-CPRI) is introduced via detailed analysis of its working principles and performance. It comprises two corner-cube retroreflectors (CCRs), a reflecting mirror (RM), and a beam splitter. For each interference output of an ideal W-CPRI, the two beams recombine and have the same output direction, including a tilted CCR. In a deformed W-CPRI structure, an optical path difference can be produced by inserting an optical element that changes the optical path in the interferometer arm of the W-CPRI. The posture deviations of the RM and the CCRs in the W-CPRI are analyzed. In addition, a proof-of-concept experiment is conducted, with the stability analyzed using the fringe similarity method. The average cosine similarity is 0.9953, revealing that this W-CPRI has high stability and strong coherence while avoiding the tilt and displacement of the interferometer arm.This paper presents a new method of postweld treatment. The 5154 aluminum alloy was cleaned by NdYAG laser after welding. The surface morphology, energy spectrum, friction and wear properties, hardness, and residual stress of the welded joint at different cleaning speeds were studied. The results show that an NdYAG laser can effectively remove the welding slag and eliminate the pores in the weld under a certain cleaning speed. When the cleaning speed is in the range of 5.2-20.7 mm/s, laser cleaning can improve the heat-affected zone’s tribological characteristics. Laser cleaning can eliminate the residual stress of the welded joint and improve the welding joint’s strength, which provides a reference for laser cleaning instead of traditional heat treatment.In this paper, the digital image correlation was innovatively applied to study the deformation and damage process of raw coal and briquette under a complex stress environment. The results show that under symmetrical loading, briquette coal shows tensile failure and that the strain field goes through three stages. The raw coal shows shear failure; the stage characteristic of the strain field is not obvious. Under asymmetric loading, the strain field evolution of raw coal and briquette shows three characteristic stages, but the briquette is more likely to form a localization phenomenon. The displacement value of the crack in the shear direction is greater than that in the tension direction, so the raw coal and briquette mainly undergo shear failure. The localized starting stress is determined by the defined statistical index function, and the localized starting stress of the raw coal and the briquette coal has a quadratic function relationship with the asymmetric coefficient.The present in vitro study proposes a novel (to the best of our knowledge) methodology employing a fiber Bragg grating sensor for the evaluation of pulp chamber temperature increase during the polymerization of the composite resin induced by the light-curing process. A fiber Bragg grating temperature sensor (FBGTS) has been developed in view of its ease of insertion into the pulp chamber with minimal widening of the pulpal canal. The temperature increase in the pulpal chamber during the polymerization of the composite resin by light curing has been characterized with varying depths of cavities of 1 mm, 1.5 mm, and 2 mm employing FBGTS. Also, the increase in temperature of the pulpal chamber during the polymerization of the composite resin has been studied with variants of the light-curing device. The obtained results are expected to be an indicator towards the potential hazard caused by heat induced pulpal injuries during the polymerization of composite resins using a light-curing device.The influence of thermal blooming on the quality of an array of Hermite-Gaussian (H-G) beams propagating in the atmosphere is studied, where the incoherent combination is considered. An analytical expression of the equivalent distortion parameter of such an array is derived and validated. As the mode order or the inverse radial fill factor of an array of H-G beams increases, the thermal blooming effect weakens, requiring more time to reach steady-state thermal blooming. The focal shift of an array of H-G beams in the atmosphere is also investigated. Owing to the thermal blooming effect in the atmosphere, the actual focus moves away from the geometric focus as the mode order decreases, which is different from the behavior in free space. Additionally, for an array of multimode beams, the actual focus moves away from the target as the weighting factor of TEM00 increases.We present a baseline correction method based on improved asymmetrically reweighted penalized least squares (IarPLS) for the Raman spectrum. This method utilizes a new S-type function to reduce the risk of baseline overestimation and speed up the reweighting process. SCH-442416 mw Simulated spectra with different levels of noise and measured spectra with strong fluorescence background from different samples are used to validate the performance of the proposed algorithm. Considering the drawbacks of the weighting rules for the asymmetrically reweighted penalized least squares (arPLS) method, we adapt an inverse square root unit (ISRU) function, which performs well in baseline correction. Compared with previous penalized least squares methods, such as asymmetric least squares, adaptive iteratively reweighted penalized least squares, and arPLS, experiments with the simulated Raman spectra have confirmed that the proposed method yields better outcomes. Experiments with the measured Raman spectra show that the IarPLS method can improve real Raman spectra within 20 ms.