In a finite one-dimensional interval, this work considers an inhomogeneous Neumann boundary value problem for a chemotaxis-convection system modeling the early phase of tumor-related angiogenesis. In ...this phase, the endothelial cells produce matrix and adhesive chemicals, both of which could decay or be degraded. In addition to primary random motion of all the above-mentioned three components, the endothelial cells move up toward the concentration gradients of adhesive chemicals, and moreover the former and the latter undergo convection with the spreading of matrix. Since the endothelial cells remain completely within the domain, zero-flux boundary conditions are imposed for them. However, to some extent, there is leaking at the boundaries as matrix and adhesive chemicals spread out beyond the domain. For any given suitably regular initial data, it is shown that the corresponding inhomogeneous initial-boundary value problem possesses a unique classical solution that is global-in-time and uniformly bounded via homogenization and a priori estimates.
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•The liquid leakage volume during the entire pipeline leaking process is calculated.•The entire leaking process is divided into 4 stages based on transient pressure.•The critical ...parameters affecting the leakage volume are analyzed.•The models’ practicality and accuracy are validated by real leaking experiments.
The accidental leakage of long-distance pressurized oil pipelines is a major area of risk, capable of causing extensive damage to human health and environment. However, the complexity of the leaking process, with its complex boundary conditions, leads to difficulty in calculating the leakage volume. In this study, the leaking process is divided into 4 stages based on the strength of transient pressure. 3 models are established to calculate the leaking flowrate and volume. First, a negative pressure wave propagation attenuation model is applied to calculate the sizes of orifices. Second, a transient oil leaking model, consisting of continuity, momentum conservation, energy conservation and orifice flow equations, is built to calculate the leakage volume. Third, a steady-state oil leaking model is employed to calculate the leakage after valves and pumps shut down. Moreover, sensitive factors that affect the leak coefficient of orifices and volume are analyzed respectively to determine the most influential one. To validate the numerical simulation, two types of leakage test with different sizes of leakage holes were conducted from Sinopec product pipelines. More validations were carried out by applying commercial software to supplement the experimental insufficiency. Thus, the leaking process under different leaking conditions are described and analyzed.
Classic surface wave imaging relies mainly on the dispersion of Rayleigh waves or Love waves. In addition to these types of waves, waveforms that arrive prior to the S wave also exhibit dispersion. ...These early dispersed waves are controlled mainly by the leaking modes and are rarely used for imaging. We applied the frequency‐Bessel transform method to waveforms that arrive before the S wave and successfully extracted multiple leaking mode dispersion curves. The extracted “0th” mode shows continuous sensitivity to S wave velocity (Vs) and mass density structure whereas the “higher” modes behave more like surface waves that are sensitive to P wave velocity (Vp) structure in the crust. Thus, the “higher” modes can be used to invert the Vp structure, which can compensate for the fact that conventional surface wave imaging methods are mainly sensitive to Vs structure.
Plain Language Summary
Dispersion refers to the phenomenon that waves have different propagation velocities at different frequencies. Seismologists usually use the dispersion of surface waves that propagate close to the Earth's surface to detect the velocity structure of the Earth's interior. In this study, the dispersion of leaking waves (leaking modes) that propagate deeper than surface waves through the Earth and have weaker energy than surface waves was extracted from array earthquake records. Unlike surface waves which are mainly sensitive to underground shear wave velocity (Vs), parts of the extracted leaking modes are mainly sensitive to underground pressure wave velocity (Vp). Therefore, this study may improve our ability to constrain the underground Vp structure and may be helpful for better understand the Earth's interior.
Key Points
We extracted multiple leaking mode dispersion curves by the F‐J method
Different leaking mode dispersion curves have different sensitivities to Vp and Vs
The extracted “higher” modes may provide effective constraints on the Vp structure of the crust
Electromagnetic radiation signal from computer display can be seen as a computer security risk if the radiation signal is intercepted and reconstructed. Electromagnetic radiation signal from computer ...display can also be called video leaking signal. Synchronising information extraction is the key problem of computer video leaking signal interception and reconstruction. To solve such problem, a novel synchronising information extraction algorithm based on spectral centroid has been developed. This study not only introduced spectral centroid into video leaking signal processing but also defined the concept of segmented spectral centroid. In addition, the uniformity degree of spectral centroid spacing distribution was defined to describe the harmonic characteristics of video leaking signal spectrum. The proposed algorithm can extract the electromagnetic radiation signal's synchronising information automatically and efficiently even with interference signal. Thus, the interception and reconstruction of electromagnetic radiation can be realised more effectively and the anti-interference performance can be improved.
Long-distance quantum key distribution (QKD) has long time seriously relied on trusted relay or quantum repeater, which either has security threat or is far from practical implementation. Recently, a ...solution called twin-field (TF) QKD and its variants have been proposed to overcome this challenge. However, most security proofs are complicated, a majority of which could only ensure security against collective attacks. Until now, the full and simple security proof can only be provided with asymptotic resource assumption. Here, we provide a composable finite-key analysis for coherent-state-based TF-QKD with rigorous security proof against general attacks. Furthermore, we develop the optimal statistical fluctuation analysis method to significantly improve secret key rate in high-loss regime. The results show that coherent-state-based TF-QKD is practical and feasible, with the potential to apply over nearly one thousand kilometers.
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