Reconstructing the acoustic far-field using a semi-circular sensor array

A method to reconstruct the acoustic far-field using a semi-circular sensor array is proposed. Firstly, the pressures in the acoustic far-field are measured by a semi-circular sensor array; then, the acoustic far-field is reconstructed based on the theory of acoustic radiation modes. The numerical simulations for reconstructing the acoustic far-field of a baffled rectangular plate are conducted. The results show that the acoustic far-field of the baffled rectangular plate can be reconstructed accurately by a few sensors on the semi-circular array. The influence of noise to the reconstruction of acoustic field is analyzed, and the robustness of the proposed method is proved. This paper provides a method for the reconstruction of acoustic far-field through a simple measuring array. The method can be applied to the acoustic field reconstruction of large structures, and has good engineering application prospects

2,4,5-Tri-2-furyl-1H-imidazole

In the crystal of the title compound, C15H10N2O3, the molecules are linked together by inter­molecular N—H⋯N hydrogen bonds into chains along the c axis. The crystal structure also shows weak inter­molecular C—H⋯π hydrogen bonds. The three furanyl rings bonded to the imidazole core are not coplanar with the latter; the dihedral angles between the furanyl and imidazole ring planes are 29.3 (2), 19.4 (2), and 4.8 (2)°

Pattern identification of biomedical images with time series: contrasting THz pulse imaging with DCE-MRIs

Objective We provide a survey of recent advances in biomedical image analysis and classification from emergent imaging modalities such as terahertz (THz) pulse imaging (TPI) and dynamic contrast-enhanced magnetic resonance images (DCE-MRIs) and identification of their underlining commonalities. Methods Both time and frequency domain signal pre-processing techniques are considered: noise removal, spectral analysis, principal component analysis (PCA) and wavelet transforms. Feature extraction and classification methods based on feature vectors using the above processing techniques are reviewed. A tensorial signal processing de-noising framework suitable for spatiotemporal association between features in MRI is also discussed. Validation Examples where the proposed methodologies have been successful in classifying TPIs and DCE-MRIs are discussed. Results Identifying commonalities in the structure of such heterogeneous datasets potentially leads to a unified multi-channel signal processing framework for biomedical image analysis. Conclusion The proposed complex valued classification methodology enables fusion of entire datasets from a sequence of spatial images taken at different time stamps; this is of interest from the viewpoint of inferring disease proliferation. The approach is also of interest for other emergent multi-channel biomedical imaging modalities and of relevance across the biomedical signal processing community

catena-Poly[[dichloridocopper(II)]-μ-4,4′-bis­(benzimidazol-1-yl)biphen­yl]

In the title compound, [CuCl2(C26H18N4)]n, the Cu(II) ion is four-coordinated by two N atoms from two 4,4′-bis­(benzo­imidazol-1-yl)biphenyl ligands and two chloride anions, in a slightly distorted tetra­hedral environment. The biphenyl ligand acts as a linear bidentate ligand, connecting the metal atoms into an infinite chain parallel to [101]. In the biphenyl ligand, the two benzene rings make a dihedral angle of 33.19 (7)°

Australobius polyspinipes sp. n., a new species of Australobius Chamberlin, 1920 (Lithobiomorpha: Lithobiidae) from China

Australobius polyspinipes sp. n. (Lithobiomorpha: Lithobiidae) was recently discovered from Tianheshan Mountain, Hebei Province, China, and it is described here. Morphologically the new species is similar to A. nodulus Ma, Song &Zhu, 2008 and A. magnus (Trozina, 1894), both recorded from China. The new species can be easily distinguished from those by having 7+7–8+8 coxosternal teeth, 10–12 ocelli on each side of the cephalic plate, 5+5 spurs on the first article of the female gonopods and differences in plectrotaxy of legs. The main morphological characters and a key to the known Chinese species of genus Australobius based on adult specimens is presented