2-D recursive bilinear model for nonlinear signal representation

To improve the mechanical performances of joints in prefabricated construction, a type of connection structure with long-fiber and metal laminated bolts (referred to as a fiber-metal connector) is proposed and investigated by simulation and theoretical methods. The results include the following: (1) The fiber layer in bolts can form a second stiffness during rotation. This mechanical characteristic improves the bearing capacities and energy dissipation ability of the connector relative to the conventional metal connector, which are expected to effectively limit the elastoplastic rotational displacement of a structure. (2) For the reason, the fiber layer can bear load in the plastic phase due to its high-strength characteristic in the length direction. (3) A bilinear model for the bearing curve of the fiber-metal connector is proposed, and equations for optimization of fiber layer thickness are obtained with a target on bearing capacity and energy dissipation ability which are approximately higher 30% and 13% than that of the conventional metal connector, respectively. This research is expected to provide a theoretical basis for the application of this fiber-metal connector in engineering and improve the safety of prefabricated structures.

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Finite-time blowup in attraction–repulsion systems with nonlinear signal production

Nonlinear Analysis Real World Applications ◽

10.1016/j.nonrwa.2021.103305 ◽

2021 ◽

Vol 61 ◽

pp. 103305

Author(s):

Meng Liu ◽

Yuxiang Li

Keyword(s):

Finite Time ◽

Finite Time Blowup ◽

Signal Production ◽

Nonlinear Signal ◽

Nonlinear Signal Production ◽

Time Blowup

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A Multi-Timescale Bilinear Model for Optimization and Control of HVAC Systems with Consistency

Energies ◽

10.3390/en14020400 ◽

2021 ◽

Vol 14 (2) ◽

pp. 400 ◽

Cited By ~ 1

Author(s):

Zelin Nie ◽

Feng Gao ◽

Chao-Bo Yan

Keyword(s):

Optimization Model ◽

Air Conditioning ◽

State Of The Art ◽

Hvac Systems ◽

Practical Significance ◽

Hvac System ◽

Bilinear Model ◽

Optimization And Control ◽

And Control ◽

Slow Timescale

Reducing the energy consumption of the heating, ventilation, and air conditioning (HVAC) systems while ensuring users’ comfort is of both academic and practical significance. However, the-state-of-the-art of the optimization model of the HVAC system is that either the thermal dynamic model is simplified as a linear model, or the optimization model of the HVAC system is single-timescale, which leads to heavy computation burden. To balance the practicality and the overhead of computation, in this paper, a multi-timescale bilinear model of HVAC systems is proposed. To guarantee the consistency of models in different timescales, the fast timescale model is built first with a bilinear form, and then the slow timescale model is induced from the fast one, specifically, with a bilinear-like form. After a simplified replacement made for the bilinear-like part, this problem can be solved by a convexification method. Extensive numerical experiments have been conducted to validate the effectiveness of this model.

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Femtosecond Laser Fabrication of Hybrid Metal-Dielectric Structures with Nonlinear Photoluminescence

Photonics ◽

10.3390/photonics8040121 ◽

2021 ◽

Vol 8 (4) ◽

pp. 121

Author(s):

Ekaterina Ponkratova ◽

Eduard Ageev ◽

Filipp Komissarenko ◽

Sergei Koromyslov ◽

Dmitry Kudryashov ◽

...

Keyword(s):

Visible Spectral Region ◽

Single Step ◽

Hybrid Nanostructures ◽

Nonlinear Properties ◽

Nanophotonic Devices ◽

Sensing Applications ◽

Structure Morphology ◽

Wide Range ◽

Nonlinear Signal ◽

Dielectric Structures

Fabrication of hybrid micro- and nanostructures with a strong nonlinear response is challenging and represents a great interest due to a wide range of photonic applications. Usually, such structures are produced by quite complicated and time-consuming techniques. This work demonstrates laser-induced hybrid metal-dielectric structures with strong nonlinear properties obtained by a single-step fabrication process. We determine the influence of several incident femtosecond pulses on the Au/Si bi-layer film on produced structure morphology. The created hybrid systems represent isolated nanoparticles with a height of 250–500 nm exceeding the total thickness of the Au-Si bi-layer. It is shown that fabricated hybrid nanostructures demonstrate enhancement of the SHG signal (up to two orders of magnitude) compared to the initial planar sample and a broadband photoluminescence signal (more than 200 nm in width) in the visible spectral region. We establish the correlation between nonlinear signal and phase composition provided by Raman scattering measurements. Such laser-induced structures have significant potential in optical sensing applications and can be used as components for different nanophotonic devices.

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