Well-posedness and strong attractors for a beam model with degenerate nonlocal strong damping

This paper is devoted to initial-boundary value problem of an extensible beam equation with degenerate nonlocal energy damping in $\Omega\subset\mathbb{R}^n$: $u_{tt}-\kappa\Delta u+\Delta^2u-\gamma(\Vert \Delta u\Vert^2+\Vert u_t\Vert^2)^q\Delta u_t+f(u)=0$. We prove the global existence and uniqueness of weak solutions, which gives a positive answer to an open question in [24]. Moreover, we establish the existence of a strong attractor for the corresponding weak solution semigroup, where the ``strong" means that the compactness and attractiveness of the attractor are in the topology of a stronger space $\mathcal{H}_{\frac{1}{q}}$.Comment: 27 page

Finite-dimensionality of attractors for wave equations with degenerate nonlocal damping

In this paper we study the fractal dimension of global attractors for a class of wave equations with (single-point) degenerate nonlocal damping. Both the equation and its linearization degenerate into linear wave equations at the degenerate point and the usual approaches to bound the dimension of the entirety of attractors do not work directly. Instead, we develop a new process concerning the dimension near the degenerate point individually and show the finite dimensionality of the attractor.Comment: 33 page

Characterization of marine shale in Western Hubei Province based on unmanned aerial vehicle oblique photographic data

The marine shale in the Sinian Doushantuo Formation of Qinglinkou outcrop section is well developed, but the current characterization methods for outcrops are unsatisfactory. In this paper, the data of outcrop in the field study area were collected by Unmanned Aerial Vehicle, then processed and interpreted by oblique photography technology combined with manual investigation. Subsequently, we established a quantitative geological knowledge database of the shale formations and carried out the typical section of anatomy analysis. The results showed that the high-precision image information captured by unmanned aerial vehicle oblique photography technology can be well coupled with a three-dimensional coordinate system. The three-dimensional digital model was used to characterize the lithologic assemblage, thickness and distribution characteristics of the target reservoir. Based on this digital model, we established the three-dimensional lithology and the total organic carbon models of the outcrop area. The spatial distribution characteristics of interbedding between marine dolomite and shale in the outcrop area were displayed, and the distribution of total organic carbon was revealed under lithological constraints. The models are beneficial for the analysis and prediction of the lithology and total organic carbon, which is of great significance to the understanding of shale gas sweet spots.Cited as: Yin, S., Feng, K., Nie, X., Chen, Q., Liu, Y., Wang, P. Characterization of marine shale in Western Hubei Province based on unmanned aerial vehicle oblique photographic data. Advances in Geo-Energy Research, 2022, 6(3): 252-263. https://doi.org/10.46690/ager.2022.03.0

Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogans strain Lai

<p>Abstract</p> <p>Background</p> <p>Pathogenic <it>Leptospira </it>species cause leptospirosis, a zoonotic disease of global importance. The spirochete displays active rotative mobility which may contribute to invasion and diffusion of the pathogen in hosts. FliY is a flagellar motor switch protein that controls flagellar motor direction in other microbes, but its role in <it>Leptospira</it>, and paricularly in pathogenicity remains unknown.</p> <p>Results</p> <p>A suicide plasmid for the <it>fliY </it>gene of <it>Leptospira interrogans </it>serogroup Icterohaemorrhagiae serovar Lai strain Lai that was disrupted by inserting the ampicillin resistance gene (<it>bla</it>) was constructed, and the inactivation of <it>fliY </it>gene in a mutant (<it>fliY</it>^-) was confirmed by PCR and Western Blot analysis. The inactivation resulted in the mRNA absence of <it>fliP </it>and <it>fliQ </it>genes which are located downstream of the <it>fliY </it>gene in the same operon. The mutant displayed visibly weakened rotative motion in liquid medium and its migration on semisolid medium was also markedly attenuated compared to the wild-type strain. Compared to the wild-type strain, the mutant showed much lower levels of adhesion to murine macrophages and apoptosis-inducing ability, and its lethality to guinea pigs was also significantly decreased.</p> <p>Conclusion</p> <p>Inactivation of <it>fliY</it>, by the method used in this paper, clearly had polar effects on downstream genes. The phentotypes observed, including lower pathogenicity, could be a consequence of <it>fliY </it>inactivation, but also a consequence of the polar effects.</p

Controlling two chaotic lasers via OD-DCF

We present a novelty optoelectronic delay double-cross-feedback (OD-DCF) scheme to control two chaotic lasers based on coupled lasers. We design out the OD-DCF technical solution to convert two lights from two lasers into two photocurrents by two photo-detectors, and then the delay photocurrents are cross-fed back to each other’s lasers respectively to suppress two chaotic oscillations and guide two laser’s dynamics behaviours, respectively. By adjusting the feedback levels and delayed time of OD-DCF, two lasers can obtain chaos-control and show all kinds of dynamics behaviours. We find that chaotic oscillation behaviours of two lasers are suppressed into a stable state and different quasi-cycle states, such as a cycle-one, cycle-two, a cycle-three, a cycle-four, and other quasi-cycle states. We find also that two movement behaviours of two lasers can be controlled to lead to two different cycle-double states. The results prove that the control of two chaotic lasers can be effectively realized via OD-DCF. It is very helpful for our studies of control science, nonlinear optics, chaos, and laser