Global Existence for the Multi-Dimensional Compressible Viscoelastic flows

The global solutions in critical spaces to the multi-dimensional compressible viscoelastic flows are considered. The global existence of the Cauchy problem with initial data close to an equilibrium state is established in Besov spaces. Using uniform estimates for a hyperbolic-parabolic linear system with convection terms, we prove the global existence in the Besov space which is invariant with respect to the {scaling} of the associated equations. Several important estimates are achieved, including a smoothing effect on the velocity, and the $L^1-$decay of the density and deformation gradient

High-performance Power Allocation Strategies for Active IRS-aided Wireless Network

Due to its intrinsic ability to combat the double fading effect, the active intelligent reflective surface (IRS) becomes popular. The main feature of active IRS must be supplied by power, and the problem of how to allocate the total power between base station (BS) and IRS to fully explore the rate gain achieved by power allocation (PA) to remove the rate gap between existing PA strategies and optimal exhaustive search (ES) arises naturally. First, the signal-to-noise ratio (SNR) expression is derived to be a function of PA factor beta [0, 1]. Then, to improve the rate performance of the conventional gradient ascent (GA), an equal-spacing-multiple-point-initialization GA (ESMPI-GA) method is proposed. Due to its slow linear convergence from iterative GA, the proposed ESMPI-GA is high-complexity. Eventually, to reduce this high complexity, a low-complexity closed-form PA method with third-order Taylor expansion (TTE) centered at point beta0 = 0.5 is proposed. Simulation results show that the proposed ESMPI-GA and TTE obviously outperform existing methods like equal PA

Commercial economic value of non-metallic fiber concrete

Non-metallic fiber concrete is a new type of high-performance concrete with excellent crack resistance, toughness and durability. And mostly plant fibers have strong environmental value and sustainable development performance, so it is widely used in construction, bridges, roads and other fields, and has a high commercial economic value. In this paper, the economic value of non-metallic fiber concrete is evaluated by a comprehensive analysis of its cost-effectiveness and commercial prospects. The results show that non-metallic fiber concrete has low maintenance cost and long service life, which can bring significant economic benefits to the project. Meanwhile, with the continuous development of technology and market expansion, the commercial prospect of non-metallic fiber concrete is broader