Raptor migration monitoring in the spring of 2009 at Baiwangshan, Beijing

Abstract

Following a series of surveys since 2003, a full-seasonal raptor count was undertaken at Baiwangshan, a mountain in the vicinity of Beijing, from 6 March to 22 May 2009, when 3802 individual birds of 23 species were recorded. Four species, i.e., Oriental Honey Buzzard (Pernis ptilorhynchus), Common Buzzard (Buteo buteo), Eurasian Sparrow Hawk (Accipiter nisus) and Gray-faced Buzzard (Butastur indicus) together accounted for up 90% of the total and P. ptilorhynchus alone for 70%. Raptor passage of such magnitude and diversity at an inland site in China was unheard of up to then. As well, 113 other migrants were recorded at the site during this period, including 24 water birds, 74 passerines and 15 others (cuckoos, owls and other migrants).

Vibration Propagation Characteristics of Binary Periodic Sandwich Panels

“…Therefore, the periodic boundary conditions can be expressed as Where, a represents the minimum periodic unit dimension.The band structure can be obtained for any wave vector k by solving eq.1 using Comsol Multiphysics software. The first Brilliouin zone and irreducible Brilliouin zone [6] are displayed in Fig. 3.…”

Propagation Characteristic in 2D Phononic Crystals with Bending Linear Defect

“…The band structure of the perfect phononic crystal is calculated by the plane-wave expansion (PWE). [1,13,20] The acoustic wave equation can be changed into a 2N×2N matrix eigenvalue equations. 441(-10≤n x ,n y ≤10) plane waves are used to calculate its band structure.…”

“…Phononic crystal, which is a composite medium composed of periodic arrays of two or more materials with different mass densities and elastic properties, has attracted much research interest in the last decade. [1] This periodic structure of these composite materials gives them peculiar properties: absolute acoustic band gaps, in which sound and vibration are all forbidden in any direction. [2,3,4,5,6,16,18,19] Motivation for studying materials with phononic band gaps is their potential applications such as acoustic filters, ultrasonic array transducers and acoustic mirrors.…”

Transmission Properties in 2D Phononic Crystal Thin Plate with Linear Defect

“…Phononic crystal, which is a composite medium composed of periodic arrays of two or more materials with different mass densities and elastic properties, has attracted much research interest in the last decade. [1] At present, the theoretical research for phononic crystal has focused on formation mechanism of band gap, the structure of wide band and special physical properties, etc. Periodic structure of these composite materials gives them peculiar properties such as forbidden propagate of sound waves with a range of frequencies, namely absolute acoustic band gaps.…”