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排序方式: 共有175条查询结果,搜索用时 15 毫秒
1.
数据同化凭借其在数值预报中将观测数据与理论模型相结合的特点,目前广泛应用于遥感图像处理及图像融合领域。文中介绍了数据同化的含义和数据同化系统的构成,并分析了其应用于图像融合的原理;结合现有的研究成果着重分析了数据同化框架下结合不同优化算法的图像融合方法,并对其进行分类比较,给出了各方法的优缺点和研究成果及应用;最后在总结了各种基于数据同化的图像融合方法普遍存在的问题的基础上,探讨了进一步发展与研究的方向。 相似文献
2.
伴随着新媒体广播电视行业信息化建设的加快,对计算机的使用也越来越广泛,基于网络连接的计算机信息安全问题也日益突出,信息安全保密显得尤为重要.针对计算机信息的安全威胁,怎样才能确保信息的安全性,本文通过阐述信息安全保密的概念、分析信息安全的现状及威胁因素,最终提出信息保密安全技术的具体方法. 相似文献
3.
王宇 《数字社区&智能家居》2011,(7X):5120-5121
该文介绍了一种基于ASP技术的电子商务网站中购物车模块的设计与实现。在设计中分析了购物车的数据流程,重点对购物车容器模块和添加商品功能模块进行了设计和实现。为电子商务网站开发进行了一个有益的探索。 相似文献
4.
Multifunctional properties of nanomaterials becomes a hot topic in nano research for the development of multifunctional devices, because modern devices need multifunctional platform for the high efficient plural performance on a single device. Here, we introduce a multifunctional π-conjugated poly (3-methylthiophene) (P3MT) nanotube (NT), showing controllable optical and electrical properties through the control of doping level. P3MT NTs were electrochemically synthesized in the low temperature (−40 °C) on the nanoporous template. The change of doping level by post cyclic voltammetry (CV) treatment on the P3MT lead the variance of polaron/bipolaron band, resulting into the drastic change of ultraviolet-visible absorption and photoluminescence properties. While P3MT NTs before CV treatment show an ohmic behavior in the current-voltage characteristics, those after CV treatment show high photocurrent. From the field emission experiment, the P3MT NTs before CV treatment have a relatively low turn-on electric field and stable electron emission property compared to the P3MT NTs after CV treatment. This shows that the π-conjugated polymers should be shed new light on their multifunctionality for the potential application to the multifunctional platform of opto-electronic nanodevices. 相似文献
5.
A physically-based compact model of organic thin-film transistors suitable for CAD simulators is proposed. It is worked out by means of a newly developed and particularly simple form of the charge-sheet model: the symmetric quadrature of the accumulation charge. The model is based on the variable-range hopping and accounts for both deep and tail states. It is simple, symmetric, accurately accounts for the below-threshold, linear, and saturation regimes via a unique formulation. The symmetric quadrature is accurate within 5% in all regions of operation and the resulting current model is suitable both for p- and n-type transistors. The model leads to a significant simplification of the drain current and of the quasi-static expressions of the terminal charges based on the Ward–Dutton partition. Finally, the symmetric quadrature leads to an explicit and analytically tractable solution for the surface potential as a function of position in the device channel that can be extremely useful to implement advanced physical effects. 相似文献
6.
通过对PC/104总线协议的分析,提出相应总线控制器的设计方法.基于面向航空领域应用所具备的特殊要求以及SoC系统的特点,对设计的可靠性及功耗方面做出改进,包括对关键信号的去噪音处理;为从已陷入长等待的状态恢复至正常模式而加入的延时等待逻辑;门控时钟被采用以作为正常工作模式与睡眠工作模式的切换;对主要功耗部分状态机进行优化编码.使用FPGA测试结果表明,该PC/104总线控制器设计安全可靠,功耗低,可以很好地支持大部分PC/104总线设备. 相似文献
7.
8.
Chidong Liu Laifei Cheng Xingang Luan Hui Mei 《Journal of the European Ceramic Society》2009,29(3):481-487
Tensile fatigue-stressed oxidation experiments were conducted at 1300 °C in oxidizing atmosphere to identify the failure modes and degradation mechanism of a SiC-coated carbon/carbon composite. Five peak fatigue stresses were selected between 90 and 150 MPa and the results showed that the higher the applied stress, the shorter the composite life. Electrical resistance of the composite was acquired in real-time. The composite resistance appeared a slight drop in the initial fatigue period and followed by a continuous increase until failure. Both the changes in modulus and resistance revealed the shrinking core mechanism in the fatigue-stressed oxidation experiments. A model was developed based on a half-cylinder oxidation pattern. Simulations were conducted on the basis of this model, and the results agreed with the experimental data fairly well. 相似文献
9.
Three hybrid host materials, mCP-PhSiPh3, mCP-L-PhSiPh3, and tBu-mCP-L-PhSiPh3, have been synthesized and characterized for their thermal, morphological, electrochemical, fluorescence, phosphorescence, and electroluminescence properties. The flexible spacer in mCP-L-PhSiPh3 and tBu-mCP-L-PhSiPh3 makes them maintain high triplet energies at about 3.00 eV due to the interruption of π-conjugation. The introduction of the tert-butyl group at the electrochemically active C3 and C6 sites of the carbazole moiety greatly improves thermal and electrochemical stability of the host tBu-mCP-L-PhSiPh3. Blue and green phosphorescent organic light-emitting diodes (PhOLEDs) based on the non-conjugated hosts exhibit external quantum efficiencies at around 15 and 21%, respectively. Higher current densities in PhOLEDs hosted by mCP-PhSiPh3 produce current leakage, resulting in lower efficiencies, especially in green PhOLEDs. The green PhOLEDs using non-conjugated hosts show improved device lifetime in comparison with the mCP-PhSiPh3 based PhOLED because of enhanced morphological stability. The operational stability of the tBu-mCP-L-PhSiPh3 based device is further raised because of improved electrochemical stability by employing the tert-butyl group. Our results demonstrate that both the flexible linkage and the blocking of the electrochemically active sites are crucial measures to realize long-lived PhOLED devices. 相似文献
10.
针对数字网络视频监控系统的需求,设计一种基于MPEG-4网络视频服务器。使用基于MPG440的MPEG-4实时视频压缩卡压缩采集到的音视频数据,利用循环队列实现音视频数据的压缩,同时运用多线程技术以及传输机制解决网络数据的传输,从而有效克制了画面不清晰、音视频不同步、马赛克等现象,保证客户监看时音视频实时性和同步性。经过实验证明,该方案经济高效,可应用在多种需要音视频监控的场合。 相似文献