机构

• 长春光学精密机械与物... [2]
• 地理科学与资源研究所 [1]

采集方式

• OAI收割 [3]

内容类型

• 会议论文 [2]
• SCI/SSCI论文 [1]

发表日期

• 2016 [1]
• 2013 [1]
• 2010 [1]

学科主题

筛选

浏览/检索结果: 共3条，第1-3条 帮助 条数/页： 5101520253035404550556065707580859095100 排序方式： 请选择题名升序题名降序提交时间升序提交时间降序作者升序作者降序发表日期升序发表日期降序 Assessing methods of identifying open water bodies using Landsat 8 OLI imagery SCI/SSCI论文  OAI收割 2016 作者:  Liu Z. F.;  Yao, Z. J.;  Wang, R.   |  收藏  |  浏览/下载：23/0  |  提交时间：2017/11/09 Remote sensing imagery  Normalized difference water index (NDWI)  Water  body extraction  Optimized threshold  Tibetan plateau  Spectral  reflectance  remotely-sensed imagery  thematic mapper  neural-network  time-series  index ndwi  tm data  classification  lake  delineation  features   Structural amelioration of 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) (EI CONFERENCE) 会议论文  OAI收割 2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China 作者:  Liu Y.;  Liu Y.;  Wang L.;  Wang L.;  Wang L. 收藏  |  浏览/下载：20/0  |  提交时间：2013/03/25 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) has an important application in laser display. We constructed and optimized a 920 nm OPS-VECSEL with active region of In0.09Ga0.91As quantum well (QW) system pumped by 808 nm laser diode module. By the finite element method  self-consistent solutions of the semiconductor electronic and optical equations are realized to calculate the characteristics parameters of OPS-VECSEL. The performances of device especially the mode  the threshold and the optical-optical translation efficiency were analyzed by dealing with different number of QWs (1  2 and 3) in one period  QW depth  barrier width  the component and dimension of the non-absorption layer. We chose an improved structure of them. On this basis  we ameliorated the number of QW periods and the simulation showed that in order to obtain high performance device  the choice of the number of QW periods must be cautious. (2013) Trans Tech Publications  Switzerland.   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：28/0  |  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.