Mechanical characteristics and design parameter analysis of spherical hinge structure for swivel bridge.

As the core component of a swivel bridge, the spherical hinge structure exhibits complex mechanical behavior under high pressure, making it challenging to describe accurately through theoretical analysis or on-site monitoring. In this context, this paper systematically examined the mechanical characteristics and key design parameters of a simplified spherical hinge structure using numerical simulations and formula derivation. Additionally, an indoor scaled test was conducted based on a representative spherical hinge structure to further investigate its mechanical properties.

Conical conformal OAM-generating transmitarray with high transmission double C-shaped grating metasurface.

This paper presents a conical conformal transmitarray (CCTA) with high transmission double C-shaped grating metasurface for generating orbital angular momentum (OAM) vortex waves. A double C-shaped grating metasurface element is proposed to achieve the 360° phase coverage in the 11-13 GHz bandwidth with a high transmission coefficient of more than 0.92.

Improved estimation of CO emissions from thermal power plants based on OCO-2 XCO retrieval using inline plume simulation.

CO emissions from power plants are the dominant source of global CO emissions, thus in the context of global warming, accurate estimation of CO emissions from power plants is essential for the effective control of carbon emissions. Based on the XCO retrievals from the Orbiting Carbon Observatory 2 (OCO-2) and the Gaussian Plume Model (GPM), a series of studies have been carried out to estimate CO emission from power plants. However, the GPM is an ideal model, and there are a number of assumptions that need to be made when using this model, resulting in large uncertainties in the inverted emissions.

Auxiliary differential equation (ADE) method based complying-divergence implicit FDTD method for simulating the general dispersive anisotropic material.

The preceding works introduced the leapfrog complying divergence implicit finite-difference time-domain (CDI-FDTD) method, which exhibits high accuracy and unconditional stability. In this study, the method is reformulated to simulate general electrically anisotropic and dispersive media. The auxiliary differential equation (ADE) method is employed to solve the equivalent polarization currents, which are then integrated into the CDI-FDTD method.

Dispersion engineering of spoof plasmonic metamaterials via interdigital capacitance structures.

This work presents an approach to realize the dispersion engineering of spoof plasmonic metamaterials with controllable cutoff frequencies. Interdigital capacitance structures are applied to construct the unit cells. Dispersion properties are firstly analyzed to investigate the effects of interdigital capacitance, and the influence of the geometrical parameters of the proposed unit cell on the cutoff frequencies is studied.

The Nord Stream pipeline gas leaks released approximately 220,000 tonnes of methane into the atmosphere.

Sudden mega natural gas leaks of two Nord Stream pipelines in the Baltic Sea (Denmark) occurred from late September to early October 2022, releasing large amounts of methane into the atmosphere. We inferred the methane emissions of this event based on surface in situ observations using two inversion methods and two meteorological reanalysis datasets, supplemented with satellite-based observations. We conclude that approximately 220 ± 30 Gg of methane was released from September 26 to October 1, 2022.

A -shaped artistic patch antenna for dual-band circular polarization.

This article presents a novel single-feed circularly polarized patch antenna for dual-band (2.6 and 3.4 GHz) applications.

A Correntropy-Based Proportionate Affine Projection Algorithm for Estimating Sparse Channels with Impulsive Noise.

A novel robust proportionate affine projection (AP) algorithm is devised for estimating sparse channels, which often occur in network echo and wireless communication channels. The newly proposed algorithm is realized by using the maximum correntropy criterion (MCC) and the data reusing scheme used in AP to overcome the identification performance degradation of the traditional PAP algorithm in impulsive noise environments. The proposed algorithm is referred to as the proportionate affine projection maximum correntropy criterion (PAPMCC) algorithm, which is derived in the context of channel estimation framework.

Non-destructive classification of apple bruising time based on visible and near-infrared hyperspectral imaging.

Background: Bruising time of apple is one of the most important factors for internal quality assessment. The present study aimed to establish a non-destructive method for the classification of apple bruising time using visible and near-infrared (VNIR) hyperspectral imaging. In this study, VNIR hyperspectral images were obtained and analyzed at seven bruising periods.

Active Electro-Location of Objects in the Underwater Environment Based on the Mixed Polarization Multiple Signal Classification Algorithm.

This article proposes a novel active localization method based on the mixed polarization multiple signal classification (MP-MUSIC) algorithm for positioning a metal target or an insulator target in the underwater environment by using a uniform circular antenna (UCA). The boundary element method (BEM) is introduced to analyze the boundary of the target by use of a matrix equation. In this method, an electric dipole source as a part of the locating system is set perpendicularly to the plane of the UCA.

Cross-scale cost aggregation integrating intrascale smoothness constraint with weighted least squares in stereo matching.

Cross-scale cost aggregation (CSCA) allows pixel-wise multiscale interaction in the aggregated cost computation. This kind of multiscale constraint strengthens the consistency of interscale cost volume and behaves well in a textureless region, compared with single-scale cost aggregation. However, the relationship between neighbors' cost is ignored.

Smooth approximation l(0)-norm constrained affine projection algorithm and its applications in sparse channel estimation.

We propose a smooth approximation l(0)-norm constrained affine projection algorithm (SL0-APA) to improve the convergence speed and the steady-state error of affine projection algorithm (APA) for sparse channel estimation. The proposed algorithm ensures improved performance in terms of the convergence speed and the steady-state error via the combination of a smooth approximation l(0)-norm (SL0) penalty on the coefficients into the standard APA cost function, which gives rise to a zero attractor that promotes the sparsity of the channel taps in the channel estimation and hence accelerates the convergence speed and reduces the steady-state error when the channel is sparse. The simulation results demonstrate that our proposed SL0-APA is superior to the standard APA and its sparsity-aware algorithms in terms of both the convergence speed and the steady-state behavior in a designated sparse channel.

An improved proportionate normalized least-mean-square algorithm for broadband multipath channel estimation.

To make use of the sparsity property of broadband multipath wireless communication channels, we mathematically propose an l p -norm-constrained proportionate normalized least-mean-square (LP-PNLMS) sparse channel estimation algorithm. A general l p -norm is weighted by the gain matrix and is incorporated into the cost function of the proportionate normalized least-mean-square (PNLMS) algorithm. This integration is equivalent to adding a zero attractor to the iterations, by which the convergence speed and steady-state performance of the inactive taps are significantly improved.

A CPW-fed circular wide-slot UWB antenna with wide tunable and flexible reconfigurable dual notch bands.

A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR.