中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共4条，第1-4条

帮助

条数/页：排序方式：
	An optimal method for frequency-domain finite-difference solution of 3D scalar wave equation 期刊论文 OAI收割 CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2018, 卷号: 61, 期号: 3, 页码: 1095-1108 作者: Fan Na; Cheng JingWang; Qin Lei; Zhao LianFeng; Xie XiaoBi \| 收藏 \| 浏览/下载：35/0 \| 提交时间：2018/09/26 3D acoustic wave equation Frequency domain Finite difference Optimized coefficients
	An optimal method for frequency-domain finite-difference solution of 3D scalar wave equation 期刊论文 OAI收割 CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2018, 卷号: 61, 期号: 3, 页码: 1095-1108 作者: Fan Na; Cheng JingWang; Qin Lei; Zhao LianFeng; Xie XiaoBi \| 收藏 \| 浏览/下载：36/0 \| 提交时间：2018/09/26 3D acoustic wave equation Frequency domain Finite difference Optimized coefficients
	Theoretical analysis of emission characteristics of second-order distributed feedback semiconductor lasers (EI CONFERENCE) 会议论文 OAI收割 Semiconductor Lasers and Applications IV, October 18, 2010 - October 19, 2010, Beijing, China 作者: Liu Y.; Liu Y.; Qin L.; Liu Y.; Wang L. 收藏 \| 浏览/下载：24/0 \| 提交时间：2013/03/25 Based on the modified coupled-wave theory the emission characteristics including threshold gain photon density distribution in the cavity and external differential quantum efficiency for second-order DFB lasers are investigated. Numerical simulation results show that for given device structure with wavelength of 1.55 m the feedback coupling coefficient and the surface radiation coupling coefficient of the second-order grating have great influence on the emission characteristics of the device. By choosing different duty cycles of the grating we can change the two coupling coefficients which affect the emission characteristics. For an overall consideration an optimal duty cycle of 0.43 is chosen. The optimized results show that the device works without degeneracy modes and spatial burning hole. Besides the side-mode suppress ratio (SMSR) and external differential quantum efficiency reach as high as 42 dB and 47% respectively. 2010 SPIE.
	Multiwavelet based multispectral image fusion for corona detection (EI CONFERENCE) 会议论文 OAI收割 ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China 作者: Wang X.; Yang H.-J.; Sui Y.-X.; Yan F.; Yan F. 收藏 \| 浏览/下载：29/0 \| 提交时间：2013/03/25 Image fusion refers to the integration of complementary information provided by various sensors such that the new images are more useful for human or machine perception. Multiwavelet transform has simultaneous orthogonality symmetry compact support and vanishing moment which are not possible with scalar wavelet transform. Multiwavelet analysis can offer more precise image analysis than wavelet multiresolution analysis. In this paper a new image fusion algorithm based on discrete multiwavelet transform (DMWT) to fuse the dual-spectral images generated from the corona detection system is presented. The dual-spectrum detection system is used to detect the corona and indicate its exact location. The system combines a solar-blind UV ICCD with a visible camera where the UV image is useful for detecting UV emission from corona and the visible image shows the position of the corona. The developed fusion algorithm is proposed considering the feature of the UV and visible images adequately. The source images are performed at the pixel level. First a decomposition step is taken with the DMWT. After the decomposition step a pyramid for each source image in each level can be obtained. Then an optimized coefficient fusion rule consisting of activity level measurement coefficient combining and consistency verification is used to acquire the fused coefficients. This process reduces the impulse noise of UV image. Finally a new fused image is obtained by reconstructing the fused coefficients using inverse DMWT. This image fusion algorithm has been applied to process the multispectral UV/visible images. Experimental results show that the proposed method outperforms the discrete wavelet transform based approach.