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[Application progress of ultrasound exam keeping track of involving diaphragm function within clinic].
Practical formulas are derived for calculating the far-field radiation pattern and coupling coefficient of a rectangular dielectric resonator (cuboid) with free space as well as mutual coupling coefficients between two cuboids for their different orientations relative to each other. An approach is developed using the coupled mode theory and the perturbation theory for the Maxwell equations. The correctness of obtained formulas is checked against the full-wave numerical simulations performed by the COMSOL Multiphysics electromagnetic solver. In particular, the obtained formulas can be used for revealing optical features of realistic (i.e., consisting of a finite number of resonators) all-dielectric metasurfaces with arbitrary curved shapes.Current methods to retrieve optically relevant properties from ocean color observations do not explicitly make use of prior knowledge about property distributions. Here we implement a simplified Bayesian approach that takes into account prior probability distributions on two sets of five optically relevant parameters, and conduct a retrieval of these parameters using hyperspectral simulated water-leaving reflectances. We focus specifically on the ability of the model to distinguish between two optically similar phytoplankton taxa, diatoms and Noctiluca scintillans. The inversion retrieval gives most-likely concentrations and uncertainty estimates, and we find that the model is able to probabilistically predict the occurrence of Noctiluca scintillans blooms using these metrics. We discuss how this method can be expanded to include a priori covariances between different parameters, and show the effect of varying measurement uncertainty and spectral resolution on Noctiluca scintillans bloom predictions.In this paper, a novel and efficient approach for solving the beam propagation method (BPM) governing equation is proposed. The approach is based on the reformulation of the beam propagation equation to solve real system matrices only at each propagation step. The reformulated equation utilizes a leap-frog (LF) technique to couple the real and imaginary components of the field in an iterative scheme. The method yields higher processing speed by at least 30% more than that of the conventional BPM method. To validate the proposed LF-BPM method, different photonic systems, including directional couplers and multimode interferometers, are simulated. Results have been experimentally verified by comparing them with results measured for fabricated micro-photonic structures. A stability analysis was performed to study the effect of the design parameters on the performance of the proposed scheme. The proposed LF-BPM approach is considered a promising technique for efficient modeling of optical structures.Objects with shiny surfaces cannot be directly measured using the conventional structured-light method. To cope with this problem, in this paper, we propose a novel method for removing the saturated components in an image. First, the specular pixels in the image are identified using a highlight extraction algorithm. Then, based on the reflection component separation (RCS) theory, the diffuse and specular components of these specular pixels are separated. For objects with shiny surfaces, use of the RCS approach destroys the color information of highlighted pixels with a large specular reflection component. As such, finally, the color information of the highlighted pixels is recovered using an image repair process. Experimental results indicate that 95% of the highlights in the images were eliminated. The highlight caused by the strong reflecting surface can be well suppressed. This proposed method effectively overcomes the interference of reflected light and provides a feasible solution to the problems associated with the structured-light measurement of objects with smooth surfaces.A stretchable chiral metamaterial with L-shaped and T-shaped Au patterns (SCMM-LT) is proposed to generate asymmetric transmission (AT) for circularly polarized waves on the polydimethylsiloxane substrate in the mid-infrared region. selleck inhibitor The peak value of AT can reach 50.02% at the resonance wavelength of 19.1 µm, owing to the enantiomerically sensitive plasmons. With stretching along the x axis and the y axis. respectively, the band of AT shifts to a longer wavelength, which proves the SCMM-LT can be a candidate as the tunable chiral metamaterial. In the future, the proposed stretchable chiral metamaterial could potentially possess high applicability for wearable electronic devices in a variety of sensor fields.The most intuitive approach for infrared stealth, namely, the indiscriminate suppression of thermal radiation, is often at the risk of overheating the target. Spectrally selective metamaterials may solve this problem by satisfying radiative cooling as well as infrared suppression. Therefore, we have designed and fabricated a broadband metamaterial by depositing a Fabry-Perot (F-P) resonator on top of a metal pattern. The composite structure has two absorption peaks, one originating from F-P resonance, the other from the magnetic resonance of the metal pattern, and they can be merged into the 5∼8 µm range through optimization. According to Kirchhoff's law, this results in high emissivity in the 5∼8 µm range (the best choice of nonatmospheric-window ranges) and low emissivity in the 3∼5 µm and 8∼14 µm ranges (the two atmospheric windows), satisfying both infrared suppression and radiative cooling. Energy dissipation distributions indicate apparent coupling of F-P resonance and magnetic resonance, but these two resonances are stronger at their respective intrinsic wavelengths. This paper reveals an alternative method for infrared suppression with radiative cooling, which is also meaningful in the design of broad/multiband absorbers.In high-power laser facilities, the application of a traditional wavefront control method is limited under the influence of a continuous phase plate (CPP). In order to obtain a satisfactory far-field intensity distribution at the target of the beamline with the CPP, a novel deformable mirror (DM) resolution-matching-based two-stage wavefront sensorless adaptive optics method is proposed and demonstrated. The principles of the DM resolution-matching method and two-stage wavefront sensorless adaptive optics method are introduced, respectively. Based on the numerical model, the matching relationship between the actuator space of the DM and the spatial period of the CPP is investigated. By using the resolution-matched DM, the feasibility of the two-stage wavefront sensorless adaptive optics method is numerically and experimentally verified. Both the numerical and the experimental results show that the presented DM resolution-matching-based two-stage wavefront sensorless adaptive optics method could achieve the target focal spot control under the influence of the CPP, and the profile and the intensity uniformity of the corrected focal spot are optimized close to the designed ideal focal spot.
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