A Study on Nonlinear Dynamic Response of the Large-Span Roof Structure with Suspended Substructure

Nowadays, it is common to see large public buildings, e.g., stadiums, with some equipment or substructure suspended from the center of the roof. These substructures will tend to be larger and heavier the more gear is needed, which may have negative impacts on the dynamic performance of the roof structures. In this paper, to explore the dynamic response of a large-span roof structure with a suspended substructure, a real structure model is simplified into a two-degrees-of-freedom system. The essential consideration of nonlinear vibration is elaborated in the equations of motions. Approximate analytical solutions for free and forced vibrations are derived using perturbation methods, while numerical analysis is carried out to validate the solutions. The ratio of linear to nonlinear amplitude is proposed to represent the nonlinear effect of the primary structure, and the nonlinear effect, varying with structural parameters of frequency ratio, mass ratio, excitation ratio, and external force to the primary structure, is investigated. It is shown that internal resonance occurs when the structural frequency ratio is close to 1:2 and that secondary resonance takes place due to certain external excitations; internal resonance and secondary resonance will magnify the amplitude of the primary structure during vibration. Finally, a case of a designed practical dome with a suspended substructure is studied to verify the outcomes from the above research. According to these findings, some design proposals for this type of structure are provided.

The Nonlinear Impact of Institutional Quality on International Reserves: International Evidence

This paper investigates the nonlinear effect of institutional quality on the holding of international reserves by applying the two-step system generalized method of moments on data consisting of 67 countries from 1996 to 2016. The hypothesis is that the association between institutional quality and international reserves has an inverted U pattern. The coefficient sign of the institutional quality and its square term supports the hypothesis. Besides, the marginal effects suggest that the higher the institutional quality index, the lower the demand for reserves. The outputs indicate the importance of good institutional quality in reducing the overdependence on international reserves.

Surface plasmon induced spot and line formation at interfaces of ITO coated LiNbO3 slabs and gigantic nonlinearity

Remarkable spots and lines were clearly observed at the two interfaces of indium-tin-oxide coated Z-cut Fe-doped lithium noibate plates under illumination by milliwatt continuous-wave laser light; this occurred because of the visible surface plasmons (SPs) supported by the promising non-metal plasmonic system. The intriguing observations are here explained via the SP-strengthened nonlinear effect, through consideration of the electrostatic field (which is comparable to the atomic field) and its large gradient; this hints at a promising, highly sensitive plasmonic system. The gigantic nonlinear effect discussed in this paper should be ubiquitously existed in many oxide ferroelectric/semiconductor combinations and is promising for visible plasmonic applications.

Discrete Schemes for a Class of Semilinear Hyperbolic Eqution

This paper focuses on the numerical algorithm of a class of semilinear hyperbolic equation. The dissipation term and external force source term existing in the equation enhance the nonlinearity of the model and make the nonlinear effect complicated. However, this nonlinear effect has a great influence on the discrete scheme, which cannot be neglected. Discretizing the nonlinear terms to ensure the validity of the scheme is the core issue in this paper. An effective scheme based on linearization techniques and iteration theory is proposed. It is based on the finite difference method. The efficiency of the proposed schemes was verified via some numerical examples showing that they compare well with existing methods.

The Effects of Technology Innovation Activity on CSR: Emphasizing the Nonlinear and Heterogenous Effects

In this study, we systematically investigate several effects of technology innovation activity (TIA)—proxied by Korean listed corporations’ research and development investment—on the performance of corporate social responsibility (CSR) for sustainable corporate growth and value. We find that corporate TIA positively contributes to an increase in CSR performance. Furthermore, our quantile regression estimations point to a heterogeneous effect of TIA, with a significant positive impact on CSR performance at the middle and higher quantiles of the distribution of the dependent variable of CSR performance. Interestingly, we capture a U-shaped nonlinear effect of TIA on the CSR performance of Korean listed corporations. Our findings alert researchers and managers to the importance of a better understanding of the relationship between CSR and TIA for sustainable corporate growth and value.