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浏览/检索结果: 共10条，第1-10条 帮助

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Study on the Snowfall Amount Triggering Regional Avalanches in Southeastern Tibet 期刊论文  OAI收割
WATER, 2025, 卷号: 17, 期号: 11, 页码: 1631
作者:  Wei, Haozhuo;  Wang, Yan;  Wang, Shaoliang;  Hao, Jiansheng;  Chen, Guoqing
  |  收藏  |  浏览/下载：9/0  |  提交时间：2025/07/18
2型糖尿病患者周围神经病变预测模型的构建 期刊论文  OAI收割
护理学杂志, 2023, 卷号: 38
作者:  李梦圆;  马学娅;  张小玉;  孙婷;  李素梅
  |  收藏  |  浏览/下载：16/0  |  提交时间：2024/11/20
Fusion of High- and Medium-Resolution Optical Remote Sensing Imagery and GlobeLand30 Products for the Automated Detection of Intra-Urban Surface Water 期刊论文  OAI收割
REMOTE SENSING, 2020, 卷号: 12, 期号: 24, 页码: 21
作者:  Li, Zhi;  Yang, Xiaomei
  |  收藏  |  浏览/下载：47/0  |  提交时间：2021/03/15
Fusion of High- and Medium-Resolution Optical Remote Sensing Imagery and GlobeLand30 Products for the Automated Detection of Intra-Urban Surface Water 期刊论文  OAI收割
REMOTE SENSING, 2020, 卷号: 12, 期号: 24, 页码: 21
作者:  Li, Zhi;  Yang, Xiaomei
  |  收藏  |  浏览/下载：39/0  |  提交时间：2021/03/15
Experiment analysis of CO2 laser disturbance on long-wave infrared HgCdTe detector (EI CONFERENCE) 会议论文  OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
作者:  Wang S.-W.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
Theoretical analysis and experimental study were carried out on the high-power CO2 laser disturbance to long-wave infrared (LWIR) HgCdTe detector in this paper. Based on the practical parameters of experiment  the theoretical model of temperature-rise is adopted to calculate the variation of the temperature with the time and the power of laser for laser irradiation on the detector. After that  the damage threshold is 110W/cm2. This experimental phenomenon well agrees with the results predicted by the theoretical calculation. The conclusions have a certain reference value for the laser defense of detector. 2011 IEEE.  the high-power laser damage mechanism to LWIR detector is discussed  and compares with the experimental results of laser irradiation the detector on the distance of 15km. The theoretical and experimental results demonstrate that the interference threshold of the detector is 20.5W/cm 2  
Analysis of laser jamming to satellite-based detector (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, June 17, 2009 - June 19, 2009, Beijing, China
作者:  Guo L.-H.;  Guo R.-H.;  Wang S.-W.
收藏  |  浏览/下载：36/0  |  提交时间：2013/03/25
The reconnaissance satellite  communication satellite and navigation satellite used in the military applications have played more and more important role in the advanced technique wars and already become the significant support and aid system for military actions. With the development of all kinds of satellites  anti-satellite laser weapons emerge as the times require. The experiments and analyses of laser disturbing CCD (charge coupled detector) in near ground have been studied by many research groups  but their results are not suitable to the case that using laser disturbs the satellite-based detector. Because the distance between the satellite-based detector and the ground is very large  it is difficult to damage it directly. However the optical receive system of satellite detector has large optical gain  so laser disturbing satellite detector is possible. In order to determine its feasibility  the theoretical analyses and experimental study are carried out in the paper. Firstly  the influence factors of laser disturbing satellite detector are analyzed in detail  which including laser power density on the surface of the detector after long distance transmission  and laser power density threshold for disturbing etc. These factors are not only induced by the satellite orbit  but dependence on the following parameters: laser average power in the ground  laser beam quality  tracing and aiming precision and atmospheric transmission. A calculation model is developed by considering all factors which then the power density entering into the detector can be calculated. Secondly  the laser disturbing experiment is performed by using LD (laser diode) with the wavelength 808 nm disturbing CCD 5 kilometer away  which the disturbing threshold value is obtained as 3.5510-4mW/cm2 that coincides with other researcher's results. Finally  using the theoretical model  the energy density of laser on the photosensitive surface of MSTI-3 satellite detector is estimated as about 100mW/cm2  which is largely exceed the disturbing threshold and therefore verify the feasibility of using this kind of laser disturbing the satellite-based detector. According to the results. using the similar laser power density absolutely saturate the requirements to laser disturbing satellite-based detector. If considering the peak power of pulsed laser  even decrease laser average power  it is also possible to damage the detector. This result will provide the reliable evidences to evaluate the effect of laser disturbing satellite-based detector. 2009 SPIE.  
Remote chlorophyll-a retrieval in eutrophic inland waters by concentration classification Taihu Lake case study 会议论文  OAI收割
International Conference on Earth Observation Data Processing and Analysis, ICEODPA,, Wuhan, China, December 28, 2008 - December 30,2008
Du, Cong; Wang, Shixin; Zhou, Yi; Yan, Fuli
收藏  |  浏览/下载：37/0  |  提交时间：2014/12/07
In order to improve the precision of phytoplankton chlorophyll-a (chla) concentration retrieval  this study classified the data into two groups (the high and the low) by chla concentration with the threshold of 50gA&bullL-1. And then build the statistical models for each group. Particularly  a modifying factor OSS/TSS was used to unmixing the spectra in the low model to improve the low relationship between spectral reflectance and chla concentrations. As a result  the concentration classification model allowed estimation of chla with a root mean square error (RMSE) of 21.12gA&bullL-1 and the determination coefficient (R2) was 0.92  comparing with RMSE of chla estimation was 35.72gA&bullL-1 and R2=0.72 in the traditional model. It shows that concentration classification is a helpful method for accurate remote chla retrieval in eutrophic inland waters. 2008 SPIE.  
Optical fiber transmission of Q-switdied Nd:YAG pulses of 10MW peak power: Mechanism of damage to the fiber (EI CONFERENCE) 会议论文  OAI收割
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies - Advanced Optical Manufacturing and Testing Technologies, November 2, 2005 - November 5, 2005, Xian, China
作者:  Wang L.;  Zhang Y.
收藏  |  浏览/下载：37/0  |  提交时间：2013/03/25
This paper presents theoretical analysis and experiment results of four different fibers transmitting 10MW peak power Nd: YAG laser pulse. The main factors limiting to optical fiber transmission of high power laser pulse is pointed  including air breakdown at focus area and surface damage of optical fiber. The theory of air breakdown and the fiber coupling conditions is described briefly. The results of study to the transmission properties and damage conditions are presented on the basis of four different types of optical fibers. The results of the experiments are further analyzed in the aspects of transmitting efficiency  air breakdown and surface damage. The local and foreign optical fibers  with plastic-cladding and silica-cladding  and step- index and graded- index fibers are tested separately in the experiments. The experiments showed that the imported fibers are able to transmit up to 10MW peak power laser pulse with no any visible damage  while energy density at the fiber output end surface is 3.54GW/cm2. For local fibers  damage on the input surface of both plastic-cladding and silica-cladding  step-index fibers was found obviously. The column damage to the graded index fiber was also found and investigated in the research. Damage mechanisms of fiber at high peak power laser pulses are summarized. High quality finishing of fiber end surface will improve damage threshold tremendously. The conclusion of the study is that transmitting Q-switched Nd:YAG pulses of 10MW peak power is feasible for the domestically made fibers if their end surfaces are properly processed.  
Analysis of the disturbance of remote aerial detector induced by laser (EI CONFERENCE) 会议论文  OAI收割
High-Power Lasers and Applications III, November 8, 2004 - November 11, 2004, Beijing, China
作者:  Zhou J.;  Fu Y.;  Guo J.;  Guo J.
收藏  |  浏览/下载：50/0  |  提交时间：2013/03/25
It is important to study the interaction effect between laser and photoelectric detector. In most of the laser detecting systems  laser must irradiate the photoelectric detector. The detector will be saturated or damaged easily if the fluence of the laser is higher than the saturation threshold of the detector. Now  many photoelectric detectors are used in space. To achieve their interaction  "Cat's eye" effect is applied to find and locate the remote aerial detector by laser. The possibility and mechanism of disturbance to remote aerial detector induced by laser are analyzed  and the factors of influence are also analyzed. The fluence of laser on the photoactive area of remote aerial detector is estimated. With two samples of CCD and TV tracking system  the mechanism of soft damage to CCD and TV tracking system induced by laser are introduced. The saturation of CCD and crosstalk of CCD are the main reasons of disturbance. When the tracking system is used in wave-door tracking mode  it will lose its tracking target if the saturation or crosstalk of CCD can enter into wave-door. At last  the influence to disturbance induced by atmosphere effect is also analyzed.  
Theoretical analysis of 980nm high power Vertical External-cavity Surface-emitting Semiconductor Laser (VECSEL) (EI CONFERENCE) 会议论文  OAI收割
ICO20: Lasers and Laser Technologies, August 21, 2005 - August 26, 2005, Changchun, China
作者:  Wang L.-J.;  Wang L.-J.;  Ning Y.-Q.;  Qin L.
收藏  |  浏览/下载：33/0  |  提交时间：2013/03/25
By using bottom-emitting structure  we will develop laser diode (LD) pumped 980 nm VECSEL with active region of InGaAs/GaAsP/AlGaAs system. Because the thickness of barrier layer and absorption layer exceed that of quantum well  single well approximation model (KP method) can be used to calculate the band structure of VECSEL. The Schrodinger equation of finite deep potential well can be adopted to calculate the energy level structures of electron  heavy and light holes. According to the transition selection rule  we theoretically obtained the emitting wavelength of VECSEL and calculated quasi-Femi energy of valence band and conduction band based on the analysis of energy level structure of electron and holes. By analyzing the gain of strained quantum wells  we calculated the gain of VECSEL using transition matrix elements of electron  heavy and light holes. We give out the threshold gain  output power and other characteristic parameters. We will study the configuration of VECSEL and pumping scheme. We designed external cavity mirror  active region and bottom-emitting structure. A LD-pumped vertical external cavity surface-emitting laser whose output power is greater than 1.0 W can be predicted.