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Abstract This paper proposes a prediction method for the tension force of support ropes in flexible rockfall barriers. The method is based on two full-scale model tests with an impact energy of 3000 kJ, as well as 36 set numerical models featuring varying lengths and impact energies. From the results of full scale tests and numerical models, it is inferred that the tension force at the end of the support rope is significantly less than that at the point of impact, exhibiting an approximate Gaussian attenuation distribution with propagation distance. To account for the attenuation of tensile forces in support ropes, a tensile attenuation coefficient is defined. Through comparative analysis of data obtained from 36 models with varying impact energies and propagation distances, the average attenuation coefficient for the upper support rope is determined to be approximately 0.7, while the average coefficient for the lower support rope is around 0.8. Utilizing the least squares method, a prediction method for the tension force of support ropes in flexible rockfall barriers is established. This method takes into account both the propagation distance and impact energy, enabling accurate predictions of the tensile behavior of the ropes under different conditions. This prediction model provides valuable insights for engineers in the design and optimization of these flexible barriers for rockfall mitigation.

Waveform design is a crucial factor in electronic surveillance (ES) systems. In this paper, we introduce an algorithm that designs a low probability of intercept (LPI) radar waveform. Our approach directly minimizes the detection probability of summation detectors based on FFT filter banks. The algorithm is derived from the general quadratic optimization framework, which inherits the monotonic properties of such methods. To expedite overall convergence, we have integrated acceleration schemes based on the squared iterative method (SQUAREM). Additionally, the proposed algorithm can be executed through fast Fourier transform (FFT) operations, enhancing computational efficiency. With some modifications, the algorithm can be adjusted to incorporate spectral constraints, increasing its flexibility. Numerical experiments indicate that our proposed algorithm outperforms existing ones in terms of both intercept properties and computational complexity. [ABSTRACT FROM AUTHOR]

Comprehensive numerical tools to investigate and analyze the surface wave attenuation on a metasurface waveguide that consists of periodic patches deposited on a dielectric substrate are presented. The surface wave attenuation is evaluated in both waveguide and open‐space environments at high frequencies around the 28‐GHz band. Two approaches including a driven modal approach and an integrated eigenmode approach for investigating the attenuation behaviors in a metasurface waveguide operating in transverse electromagnetic (TEM) mode are employed. These results show different attenuation values depending on the waveguide height due to an unavoidable coupling issue despite the same metasurface design. Thus, an alternative method for more accurately evaluating the frequency‐dependent attenuation characteristics through field distribution in open space with a customized horn antenna is proposed. A relationship between the surface wave attenuation and the propagation distance by analyzing the analytical electric field distribution at different points on the propagation path in the open space is established. Thus, this study provides an improved method for assessing surface wave attenuation characteristics, which contributes to designing surface wave control for wireless communications, wireless power transfer, signal processing, and electromagnetic compatibility. [ABSTRACT FROM AUTHOR]

The application of acoustic emission (AE) in concrete faces great challenges due to complex material parameters of concrete materials and the rapid attenuation characteristics of acoustic emission wave. In order to clarify the influence of concrete strength level on acoustic emission wave propagation characteristics and create conditions for evaluating concrete damage by acoustic emission technology, the acoustic emission technology was used to study the propagation behavior of acoustic emission waves in concrete with different strength levels through parameter analysis and fast Fourier transform. The results show that the attenuation coefficients of AE energy in C30, C40 and C50 concrete are 0.013 94, 0.010 67 and 0.005 68, respectively, and the higher the strength is, the smaller the attenuation is. The benchmark wave speeds are 3 966 m/s, 4 193 m/s and 4 411 m/s, respectively, and the higher the intensity, the faster the wave speed. The frequency distribution tends to shift from high frequency to low frequency with the increase of propagation distance, but the signal attenuation and frequency deviation of concrete with high strength are slower. The signal wave types received within 500 mm and outside 500 mm are different, which is not conducive to the acoustic emission monitoring. When monitoring the acoustic emission of concrete, the sensor spacing should be within 500 mm to ensure the monitoring accuracy. [ABSTRACT FROM AUTHOR]

First of all, the beam propagation of Super Lorentz Gaussian (SLG) profile is propagated via space, the recent research dealt extensively with the investigation of the propagation of SLG in a level of specified atmospheric. In a turbulent atmosphere of intensity and receiver field, models were derived from a new mathematical expression of intensity and analyzed. Also, to find the power scintillation indicators for the SLG beam in a random turbulence of receiver plane. The equations are obtained for the average receiver-aperture. The new beam of SLG systems generated a modified model when compared with the receiver-aperture averaging. When we revisions the parameters, firstly is started the factor source size, this affected the profile for the power propagation and the analysis proved that the average of the aperture is affected by increasing the distance of propagation length. The enhancement of the average power of the aperture effect reliably with the source size of the initial beam source depends on several factors, including the structure constant, the beam order and static value of source size. Finally, the target of this article is detected a novel of mathematical expression of the receiver intensity is applied in the system of optical communications. [ABSTRACT FROM AUTHOR]

In this paper, we study the propagation properties of a Generalized Hermite cosh-Gaussian beam (GHCGB) in uniaxial crystals orthogonal to the optical axis. Analytical expression of the GHCGB at the receiver plane is derived using Huygens–Fresnel integration. Some analyses are investigated to illustrate the effect of variations in crystal refractive indices, source beam parameters and propagation distance on the beam intensity profiles. Results indicate that a GHCGB preserves its initial profile nearly invariant for a small propagation distance and evolves into an elliptical Gaussian-like beam surrounded by the smaller beamlets in the far field due the effect of the uniaxial crystal. The beam width and the intensity distribution of received beam can be controlled by adjusting the source beam parameters and the ratio of refractive indices of the crystal. We anticipate that our results obtained in this research will be useful for the control of optical particle. [ABSTRACT FROM AUTHOR]

Waveform design is a crucial factor in electronic surveillance (ES) systems. In this paper, we introduce an algorithm that designs a low probability of intercept (LPI) radar waveform. Our approach directly minimizes the detection probability of summation detectors based on FFT filter banks. The algorithm is derived from the general quadratic optimization framework, which inherits the monotonic properties of such methods. To expedite overall convergence, we have integrated acceleration schemes based on the squared iterative method (SQUAREM). Additionally, the proposed algorithm can be executed through fast Fourier transform (FFT) operations, enhancing computational efficiency. With some modifications, the algorithm can be adjusted to incorporate spectral constraints, increasing its flexibility. Numerical experiments indicate that our proposed algorithm outperforms existing ones in terms of both intercept properties and computational complexity.

We report on the measurement of the local magnetization dynamics occurring, at units of GHz, in large aspect ratio stripes lithographed from reduced damping amorphous Fe80B20 films. The stripes were submitted to local anisotropy modifications by micrometric beam synchrotron X-ray irradiation. Our results include data on the dispersion relationships and group velocities corresponding to spin waves excited at both the non-irradiated and the irradiated regions. Whereas in the former case we observed standing spin waves with transverse-to-the stripe axis wave vector, in the latter one, for which the wave vector of the spin waves was parallel-to-the stripe axis, propagating spin waves were excited. In both regions, we measured the effective propagation distance of the spin waves, which resulted to be independent of the wave vector orientation. In the spin waves excited at the irradiated region, we also measured the decay time and effective damping coefficient, which was in good agreement with previously reported values obtained from FMR measurements in amorphous Fe80B20 continuous films. We show that the interaction of the non-irradiated and irradiated zones results, at the stripe transverse saturation remanence and under an exciting field frequency of 4 GHz, in the introduction of a π phase shift between the standing spin waves excited at both sides of the irradiated region. This result opens the possibility of using the local, transverse to the stripe axis, magnetic anisotropy easy axis induced by the X-ray irradiation as a crucial constituent of a zero-applied field spin wave phase-shifter.

We report on the measurement of the local magnetization dynamics occurring, at units of GHz, in large aspect ratio stripes lithographed from reduced damping amorphous Fe80B20 films. The stripes were submitted to local anisotropy modifications by micrometric beam synchrotron X-ray irradiation. Our results include data on the dispersion relationships and group velocities corresponding to spin waves excited at both the non-irradiated and the irradiated regions. Whereas in the former case we observed standing spin waves with transverse-to-the stripe axis wave vector, in the latter one, for which the wave vector of the spin waves was parallel-to-the stripe axis, propagating spin waves were excited. In both regions, we measured the effective propagation distance of the spin waves, which resulted to be independent of the wave vector orientation. In the spin waves excited at the irradiated region, we also measured the decay time and effective damping coefficient, which was in good agreement with previously reported values obtained from FMR measurements in amorphous Fe80B20 continuous films. We show that the interaction of the non-irradiated and irradiated zones results, at the stripe transverse saturation remanence and under an exciting field frequency of 4 GHz, in the introduction of a π phase shift between the standing spin waves excited at both sides of the irradiated region. This result opens the possibility of using the local, transverse to the stripe axis, magnetic anisotropy easy axis induced by the X-ray irradiation as a crucial constituent of a zero-applied field spin wave phase-shifter.

Scholte waves at the seafloor have significant potential for underwater detection and communication, so a study about detecting Scholte waves is very meaningful in practice. In this paper, the detection of Scholte waves at the seafloor is researched theoretically and experimentally. Acoustic models with the multilayer elastic bottom are established according to the ocean environment, and a tank experiment is designed and carried out to detect Scholte waves. Different from detecting Scholte waves in the seismic wavefield, a technique for detecting Scholte waves in the sound pressure field is proposed in this paper. The experimental results show that the proposed technique can detect Scholte waves effectively, and there are no problems such as seabed coupling and the effect of wave speeds. Furthermore, the results also show that this detection technique is still effective in conditions with a sediment layer. The existence of sediment layers changes the acoustic field conditions and affects the excitation of Scholte waves. [ABSTRACT FROM AUTHOR]

Free space optics (FSO) communication is a very recent mechanism. It is mainly needed when physical connection between the transmitter and the receiver is practically impossible and when high bandwidth data transmission is expected. This paper walks through the investigation of the performance of FSO communication adopting spectral amplitude coding optical code division multiple access (SAC-OCDMA) systems at different weather scenarios. The suggested system uses enhanced double weight codes as signature codes by 3 clients, simultaneously. To eliminate multiple access interference and phase induced intensity noise, two different detection schemes are used; single photodiode (SPD) and modified-AND subtraction detection schemes. Furthermore, a comparison between PIN and APD detectors is performed. The performance is evaluated through its propagation distance, received power, Q-factor and bit error rate (BER). The obtained numerical results reveal both Q-factor and BER are modified by 30%. Accordingly, the system performance is enhanced by 30%, when using SAC-OCDMA-FSO with SPD detection technique compared with modified-AND subtraction technique. [ABSTRACT FROM AUTHOR]

Scholte waves at the seafloor have significant potential for underwater detection and communication, so a study about detecting Scholte waves is very meaningful in practice. In this paper, the detection of Scholte waves at the seafloor is researched theoretically and experimentally. Acoustic models with the multilayer elastic bottom are established according to the ocean environment, and a tank experiment is designed and carried out to detect Scholte waves. Different from detecting Scholte waves in the seismic wavefield, a technique for detecting Scholte waves in the sound pressure field is proposed in this paper. The experimental results show that the proposed technique can detect Scholte waves effectively, and there are no problems such as seabed coupling and the effect of wave speeds. Furthermore, the results also show that this detection technique is still effective in conditions with a sediment layer. The existence of sediment layers changes the acoustic field conditions and affects the excitation of Scholte waves.

Acoustic emission (AE) is applied for the structural health evaluation of materials. It commonly uses piezoelectric sensors to detect elastic waves coming from energy releases within the material. Concerning cementitious composites as well as polymers, AE parameters have proven their potential to not only detect the existence of a defect, its location and the fracture mode, but also the developing strain field even before visible damage evolves. However, the wave propagation distance, wave dispersion due to plate geometry, heterogeneity and reflections result in attenuation and distortion of the AE waveforms. These factors render the interpretation more complex, especially for large samples. In this study, the effect of wave propagation on plain glass textile-reinforced cement (TRC) plates is investigated. Then, curved plates with different widths are mechanically loaded for bending with concurrent AE monitoring. The aim is to evaluate to what extent the plate dimensions and propagation distance influence the original AE characteristics corresponding to a certain fracture mechanism. [ABSTRACT FROM AUTHOR]

Abstract Tibetan Plateau vortices (TPVs) are important rainfall triggers in southwestern and eastern China after they move off the plateau. Characteristics of the moving‐off TPVs derived from two gridded data sets, the final operational global analysis data from the Global Forecasting System of National Centers for Environment Prediction (NCEP‐FNL) and the ERA‐interim data from the European Centre for Medium‐Range Weather Forecasts, are evaluated against the Yearbooks of Tibetan Plateau Vortex and Shear Line (YB). Generally, NCEP‐FNL captures more moving‐off TPVs in YB than ERA‐interim does. Both gridded data sets perform the best in capturing the TPVs in YB in May and the worst in July. Zonal propagation distances of TPVs are apparently better revealed in NCEP‐FNL than in ERA‐interim, and the performances of NCEP‐FNL and ERA‐interim in showing the meridional propagation distances and lifespans are similar. Positional deviations of TPVs in NCEP‐FNL and ERA‐interim reveal that both data sets show good skills in presenting the TPVs locations, and NCEP‐FNL generally performs better than ERA‐interim. In both gridded data sets, positional deviations of TPVs are larger before the TPVs move off the plateau than after moving off, and zonal deviations are always larger than meridional deviations. Before the TPVs move off, NCEP‐FNL shows no specific preference for the directions of positional deviations, whereas ERA‐interim tends to present further west TPVs locations relative to those in YB. After the TPVs move off, TPVs in both gridded data sets are always observed to the west and north of the TPVs in YB, which is more significant in ERA‐interim.

Strong shockwaves can be formed by pulse discharge in water, and are applicable in fields such as control blasting, oil production, and national defence construction. Wave front-time is an important parameter in shockwave theory and effect. In order to reveal the relationship between the wave front-time and electrical energy and hydrostatic pressure, this study proposed a wave front-time analysis model. The relations between these conditions and shockwave front-time were derived and combined with theoretical information. The shockwave front-time was obtained at several sites under different conditions of hydrostatic pressure, breakdown energy, and propagation distance. Results indicate that shockwave front-time decreases with increasing breakdown energy, when electrical energies are in the range of 1500- 3500 J. Wave front-time increases with increasing hydrostatic pressure, when hydrostatic pressures are in the 0-4 MPa range. Wave front-time increases with increasing propagation distance within 4 m. The breakdown energy and hydrostatic pressure have significant effects on the increase of the front-time as the propagation distance increases. The findings provide references for experiments on pulse discharge in water and evaluation of shockwave performance. [ABSTRACT FROM AUTHOR]

The finite-difference time-domain method was employed to simulate the propagation of a pulse-modulated surface-plasmon-polariton (SPP) wave along a planar silicon/silver interface in the near-infrared spectral regime. The signal energy on the silicon side varies with the carrier frequency, decreases with the propagation distance, and fans away from the interface as the propagation distance increases. Yet a large fraction of the signal energy on the silicon side is confined to within 250 nm of the interface even for a propagation distance of 800 nm. [ABSTRACT FROM AUTHOR]

Tibetan Plateau vortices (TPVs) are important rainfall triggers in southwestern and eastern China after they move off the plateau. Characteristics of the moving‐off TPVs derived from two gridded data sets, the final operational global analysis data from the Global Forecasting System of National Centers for Environment Prediction (NCEP‐FNL) and the ERA‐interim data from the European Centre for Medium‐Range Weather Forecasts, are evaluated against the Yearbooks of Tibetan Plateau Vortex and Shear Line (YB). Generally, NCEP‐FNL captures more moving‐off TPVs in YB than ERA‐interim does. Both gridded data sets perform the best in capturing the TPVs in YB in May and the worst in July. Zonal propagation distances of TPVs are apparently better revealed in NCEP‐FNL than in ERA‐interim, and the performances of NCEP‐FNL and ERA‐interim in showing the meridional propagation distances and lifespans are similar. Positional deviations of TPVs in NCEP‐FNL and ERA‐interim reveal that both data sets show good skills in presenting the TPVs locations, and NCEP‐FNL generally performs better than ERA‐interim. In both gridded data sets, positional deviations of TPVs are larger before the TPVs move off the plateau than after moving off, and zonal deviations are always larger than meridional deviations. Before the TPVs move off, NCEP‐FNL shows no specific preference for the directions of positional deviations, whereas ERA‐interim tends to present further west TPVs locations relative to those in YB. After the TPVs move off, TPVs in both gridded data sets are always observed to the west and north of the TPVs in YB, which is more significant in ERA‐interim. Key Points: Efficiency of NCEP‐FNL and ERA‐interim data sets in describing the Tibetan Plateau vortices are evaluatedBoth NCEP‐FNL and ERA‐interim show good skills in presenting the characteristics of Tibetan Plateau vorticesGenerally, NCEP‐FNL performs better than ERA‐interim, though with some caveats [ABSTRACT FROM AUTHOR]

Acoustic emission (AE) is applied for the structural health evaluation of materials. It commonly uses piezoelectric sensors to detect elastic waves coming from energy releases within the material. Concerning cementitious composites as well as polymers, AE parameters have proven their potential to not only detect the existence of a defect, its location and the fracture mode, but also the developing strain field even before visible damage evolves. However, the wave propagation distance, wave dispersion due to plate geometry, heterogeneity and reflections result in attenuation and distortion of the AE waveforms. These factors render the interpretation more complex, especially for large samples. In this study, the effect of wave propagation on plain glass textile-reinforced cement (TRC) plates is investigated. Then, curved plates with different widths are mechanically loaded for bending with concurrent AE monitoring. The aim is to evaluate to what extent the plate dimensions and propagation distance influence the original AE characteristics corresponding to a certain fracture mechanism.

Because of the overlapping community detection algorithm is random and easily forms the monster community, an overlapping community detection algorithm OCDA_TI based on tag influence is proposed in this paper. Firstly, the concept of subordinate degree that represents the ascription degree for this community vertices in different communities is defined in the algorithm; secondly, for the problem that the attraction between tag vertex will weaken according to the tag propagation distance increases, tag score and the attenuation factor is described. In order to avoid the problem of random selection of same label influence, the similarity measure is defined; thirdly, the calculation method of tag influence value and the termination condition of tag transmission are given based on the subordinate degree function and attenuation factor. Considering that the network structure is difficult to determine the attenuation factor, the propagation distance parameter is introduced, which combines the modularity increment maximum; Finally, the testing of the OCDA_TI algorithm in different data sets, the experimental results show that the proposed algorithm has good stability, and the quality of community detection is superior to the typical overlapping community detection algorithms. [ABSTRACT FROM AUTHOR]

Investigating spatiotemporal pattern and propagation mechanism of meteorological drought is of great significance to develop early warning system for drought-affected regions and other drought types. In this study, the spatiotemporal characteristics and evolution trend of meteorological drought represented by the standardized precipitation evapotranspiration index (SPEI) during 2016–2021 across the Yangtze River basin (YZRB) and Pearl River basin (PRB) were analyzed. The drought spatial synchronization extent and propagation mechanisms (i.e., propagation source, sink, direction, strength and distance) were also investigated through constructing the undirected and directed complex networks, respectively. The results indicate that during 1961–2021, meteorological droughts in the middle and lower reaches of the YZRB and PRB present an alleviating trend, while droughts over their upper reaches that are relatively far from coastal regions are aggravated. The drought synchronization extents at the spatial scale are classified into seven communities, where the drought events within the same community are more likely to occur synchronously and their characteristics are more similar. Moreover, the drought propagation source regions are mainly distributed over the eastern coastal regions of the YZRB, the upper coastal regions of the PRB and the headwaters of the YZRB, from where droughts start to propagate along the WSW (or WNW) direction, NE direction and ESE direction to interior regions, respectively. The sink regions are mostly distributed in the YZRB and PRB middle reaches and the southwestern parts of the YZRB upper reaches. Meteorological drought events in most regions have a propagation distance of hundreds of kilometers. This study provides new tools and insights on drought propagation and prediction and can help policy-makers formulate advanced preventive measures. • Complex networks were constructed to quantify drought spatial propagation extent and propagation mechanism. • Seven drought synchronization regions were identified in the YZRB and PRB. • The eastern coastal regions of YZRB and PRB and the upstream coastal regions of PRB are the main drought propagation sources. • Meteorological droughts propagate in hundreds of kilometers in most regions. [ABSTRACT FROM AUTHOR]

A long-range hybrid slot surface plasmon waveguiding structure that is capable of achieving ultra-small mode confinement and a long propagation distance simultaneously is proposed in this article. In comparison with the conventional long-range hybrid surface plasmon waveguide, the proposed waveguide can provide one order smaller mode area and a longer propagation distance by introducing a through-slot in the gap region. Meanwhile, the practical fabrication errors have little influence over mode properties of the waveguide. These results indicate that our designed waveguide can be a potential candidate for high-performance nanophotonic circuit and device. [ABSTRACT FROM AUTHOR]