Incorporating two coupling noises into a nonlinear competitive system with saturation effect

In this paper,a novel stochastic two-species competitive system with saturation effect is formulated,in which there exist two noise resources and their coupling mode is relatively complex and every noise source has elfect on the intrinsic growth rates of both species.With the help of some suitable Lyapunov functions,sufficient conditions for stochastic permanence are established as exponential extinction,extinction,permanence in time average and asymptotic pathwise estimation of system.The effect of coupling noise on the asymptotic behaviors of the populations is shown.

Design and characterization of a 3D encapsulation with silicon vias for radio frequency micro-electromechanical system resonator

In this paper, we present a three-dimensional（3D） vacuum packaging technique at a wafer level for a radio frequency micro-electromechanical system（RF MEMS） resonator, in which low-loss silicon vias is used to transmit RF signals.Au–Sn solder bonding is adopted to provide a vacuum encapsulation as well as electrical conductions. A RF model of the encapsulation cap is established to evaluate the parasitic effect of the packaging, which provides an effective design solution of 3D RF MEMS encapsulation. With the proposed packaging structure, the signal-to-background ratio（SBR） of 24 dB is achieved, as well as the quality factor（Q-factor） of the resonator increases from 8000 to 10400 after packaging.The packaged resonator has a linear frequency–temperature（ f –T） characteristic in a temperature range between 0℃ and 100℃. And the package shows favorable long-term stability of the Q-factor over 200 days, which indicates that the package has excellent hermeticity. Furthermore, the average shear strength is measured to be 43.58 MPa among 10 samples.

Research on Telescope TTL Coupling Noise in Intersatellite Laser Interferometry

The detection mission of gravitational waves in space is that the accuracy of the long-baseline intersatellite laser interferometry on the million-kilometer order needs to reach the order of 8 pm/Hz.Among all noise sources that affect the interferometry accuracy,tilt-to-length(TTL)coupling noise is the second largest source of noise after shot noise.This paper focuses on studying the contribution of TTL coupling noise of the telescope system in the intersatellite scientific interferometer.By referring to the laser interferometer space antenna(LISA)’s noise budget,TTL coupling noise is required to be within±25μm/rad(±300μrad).Therefore,this paper focuses on studying both the mechanism of TTL coupling noise due to the noise sources of the telescope and the method of suppressing the TTL noise,which can lay a foundation for noise distribution and the development of engineering prototypes in subsequent tasks.

Survival analysis of an impulsive stochastic facultative mutualism system with saturation effect

A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken into account.A set of sufficient criteria for extinction(exponential extinction and extinction)and permanence(permanence in time average and stochastic permanence)of the system are established.Extensive simulation figures are demonstrated to support the theoretical findings.Meanwhile,we look at the effects of coupling white noises,impulses,intrinsic growth rates,intra-specific competition rates and inter-specific mutualism rates on the survival of populations.