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21.
有扰对称信道平均信息量的计算 总被引:3,自引:1,他引:2
照相手机让诺基亚抢了风头,这真是亚洲人的失策。在日本和韩国,内置摄像头的手机早就不是什么值得炫耀的东西了。不过日本人的动作还是很快的,GD88和N8一副后来居上的架势,让人不敢小瞧。 相似文献
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Jagath C Rajapakse Choong Leong Tan Xuebin Zheng Susanta Mukhopadhyay Kanyan Yang 《IEEE engineering in medicine and biology magazine》2006,25(2):102-111
Covariance-based methods of exploration of functional connectivity of the brain from functional magnetic resonance imaging (fMRI) experiments, such as principal component analysis (PCA) and structural equation modeling (SEM), require a priori knowledge such as an anatomical model to infer functional connectivity. In this research, a hybrid method, combining independent component analysis (ICA) and SEM, which is capable of deriving functional connectivity in an exploratory manner without the need of a prior model is introduced. The spatial ICA (SICA) derives independent neural systems or sources involved in task-related brain activation, while an automated method based on the SEM finds the structure of the connectivity among the elements in independent neural systems. Unlike second-order approaches used in earlier studies, the task-related neural systems derived from the ICA provide brain connectivity in the complete statistical sense. The use and efficacy of this approach is illustrated on two fMRI datasets obtained from a visual task and a language reading task. 相似文献
23.
Chan C.C. Zheng Ming Zhao Qian C. Meng S. 《Industrial Electronics, IEEE Transactions on》2002,49(6):1342-1344
Based on the concepts of cascade multilevel converters and one-cycle technique, comparisons are conducted to characterize the distortion of the pulsewidth modulation (PWM) and one-cycle control methods that were applied to converters. Simulation results for the different control schemes are obtained in PSIM software initially to see the effect of one-cycle control different from that of PWM control. Through the comparisons, the advantages and disadvantages are identified for each method. The one-cycle scheme is better than PWM control in reducing undesirable harmonics and tracing dynamic waveforms. Simulation and experimental results are also provided to verify the conclusions. 相似文献
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王刚 《建设机械技术与管理》2006,19(10):41-42
如果说青藏铁路是一条“雪域天路”,那么宝鸡至天水高速公路就是一条“陇上天路”。宝鸡至天水是从关中平原到西北黄土高原的跨越地段,垂直跨度大,山连山,岭连岭,几乎看不到任何平原地段。作为2005年西部新开工的十大工程和交通部十二项示范工程之一,这条全长91公里的高速公路还要穿过甘肃屈指可数的林带,跨越黄河、长江两大流域,穿越甘肃最大的天然林保护基地--小陇山林业自然保护区、麦草沟自然保护区和麦积山国家森林公园。 相似文献
26.
介绍通辽市科尔沁区清河镇有线电视发展的现状,提出清河镇有线电视网络的规划设计方案,对网络指标进行具体验算,并简要分析网络建设中光缆路由的敷设方式。 相似文献
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Demir H.V. Jun-Fei Zheng Sabnis V.A. Fidaner O. Hanberg J. Harris J.S. Jr. Miller D.A.B. 《Semiconductor Manufacturing, IEEE Transactions on》2005,18(1):182-189
This work reports an easy planarization and passivation approach for the integration of III-V semiconductor devices. Vertically etched III-V semiconductor devices typically require sidewall passivation to suppress leakage currents and planarization of the passivation material for metal interconnection and device integration. It is, however, challenging to planarize all devices at once. This technique offers wafer-scale passivation and planarization that is automatically leveled to the device top in the 1-3-/spl mu/m vicinity surrounding each device. In this method, a dielectric hard mask is used to define the device area. An undercut structure is intentionally created below the hard mask, which is retained during the subsequent polymer spinning and anisotropic polymer etch back. The spin-on polymer that fills in the undercut seals the sidewalls for all the devices across the wafer. After the polymer etch back, the dielectric mask is removed leaving the polymer surrounding each device level with its device top to atomic scale flatness. This integration method is robust and is insensitive to spin-on polymer thickness, polymer etch nonuniformity, and device height difference. It prevents the polymer under the hard mask from etch-induced damage and creates a polymer-free device surface for metallization upon removal of the dielectric mask. We applied this integration technique in fabricating an InP-based photonic switch that consists of a mesa photodiode and a quantum-well waveguide modulator using benzocyclobutene (BCB) polymer. We demonstrated functional integrated photonic switches with high process yield of >90%, high breakdown voltage of >25 V, and low ohmic contact resistance of /spl sim/10 /spl Omega/. To the best of our knowledge, such an integration of a surface-normal photodiode and a lumped electroabsorption modulator with the use of BCB is the first to be implemented on a single substrate. 相似文献