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991.
In this paper, the cutoff characteristic of rectangular-shaped microshield transmission line has been analysed by edge element method. Dependence of cutoff wavelengths on the thickness of metallic signal strip, dielectric constant of dielectric substrate and the width of the rectangular-shaped ground conductor are presented in tabular form. Numerical results in this paper have important values in design of rectangular-shaped microshield lines in microwave and millimeter wave integrated circuits.  相似文献   
992.
本文主要介绍了西门子SINAMICS S120传动系统在济钢4300m新厚板轧机电动压下控制系统中的应用。  相似文献   
993.
A non-coherent receiver for impulse radio ultra-wide band(IR-UWB)is presented.The proposed receiver front-end consists of a high gain LNA,a high frequency detector and an intermediate frequency(IF)amplifier to amplify the recovered signal and drive an external test instrument.To meet the requirements of high gain and a low noise figure(NF)under moderate power consumption for the LNA,capacitor cross coupled(CCC)and current reuse techniques were adopted.The detector consists of a squarer and an integrator.The overall circuit consumes 41.2mA current with a supply voltage of 1.8 V at a 400 MHz pulse rate.The resulting energy efficiency is 0.19 nJ/pulse.A chip prototype is implemented in 0.18-μm CMOS.The die area is 2.1×1.4 mm~2 and the active area is 1.7×0.98 mm~2.  相似文献   
994.
It is widely accepted that surface enhanced Raman scattering (SERS) enhancement results from a combination of electromagnetic mechanisms (EM) and chemical mechanisms (CM). Recently, the nanoparticle‐film gap (NFG) system was studied due to its strong local enhancement field. However, there are still some technical limitations in establishing effective and simple ways for reliable and precise control of sub‐nanospacer. In addition, works on designing the nanospacer in NFG system for efficient interaction with target molecules for further improving SERS signals are rather limited. Here, a novel NFG system is proposed by introducing ultrathin monolayer graphene as well‐defined sub‐nanospacer between Ag NPs and Ag film (named G(graphene)‐NFG system). The new G–NFG system offers tremendous near‐field enhancement with one of the highest enhancement ratio of 1700 reported to date. These results show that the single‐layer graphene as a sub‐nanospacer renders the proposed G–NFG system with particularly strong EM enhancement (due to multiple couplings including the NP–NP couplings and NP‐film couplings) and additional CM enhancement in detecting some π‐conjugated molecules to function as a powerful tool in analytical science and the related fields.  相似文献   
995.
测试优化选择是测试性设计至关重要的一个步骤,主要针对测试不可靠条件下的测试优化选择问题进行了研究.首先将该问题还原为多目标问题来分析,在此基础上以测试数量、测试成本、虚警率为目标,故障检测率、隔离率为约束条件建立了问题的数学模型;然后以贝叶斯网络测试性模型为基础,利用提出的MOPSO-NSGA2算法求解该问题;最后利用所提算法对某导弹机载无线电高度表开展测试优化选择设计,并与MOPSO算法、NSGA-2算法进行对比,验证了方法的有效性与实用性.  相似文献   
996.
高可靠性P-LDMOS研究   总被引:2,自引:4,他引:2  
分析了沟道高电场分布产生原因及各个参数对高电场的影响,提出了两条沟道设计的原则——拉长沟道同时降低沟道浓度.模拟结果显示,两条原则能够有效地降低沟道两端的两个峰值电场,从而缓解沟道热载流子效应,提高P-LDMOS的可靠性.  相似文献   
997.
无线光通信中RCPT/ARQ自适应 差错控制机制的研究   总被引:1,自引:0,他引:1       下载免费PDF全文
谢伟良  汤俊雄  刘璐 《电子学报》2004,32(2):223-226
为了克服无线光通信中的光强闪烁、大气衰减等信道干扰,本文结合无线光信道下Turbo码迭代译码算法,分析了RCPT码的穿孔图案特性,在此基础上完整给出了无线光通信系统RCPT/ARQ自适应差错控制方案,仿真表明RCPT/ARQ自适应差错控制方案显著提高了链路的吞吐量和稳定性.同时结合无线光信道的特性,提出了RCPT/ARQ机制下的排序重发策略,进一步优化系统在恶劣信道条件下的链路吞吐量.  相似文献   
998.
随着网络技术和电子技术的发展,分布式计算和系统集成成为焦点。本文阐述了CORBA技术的特点及优势,并通过一个例子简单阐述了CORBA技术在系统集成中的应用。  相似文献   
999.
Multimodal imaging provides complimentary information that is advantageous in studying both cellular and molecular mechanisms in vivo, which has tremendous potential in pre‐clinical research and clinical translational imaging. It is desirable to design probes for multimodal imaging that can be administered minimally but provides multifaceted information. Herein, we demonstrate the complementary dual functional ability of a nanoconstruct for molecular imaging in both photoacoustic (PA) and surface‐enhanced Raman scattering (SERS) biosensing simultaneously in tandem. To realize this, a group of NIR active organic molecules are designed and synthesized that possess both SERS and PA activity. Nanoconstructs realized by anchoring such molecules onto gold nanoparticles are demonstrated for targeting cancer biomarkers in vivo while providing complimentary information about biodistribution and targeting efficiency. In future, such nanoconstructs could play a major role in identifying surgical margins and also for disease monitoring in translational medicine.  相似文献   
1000.
Memristors have attracted broad interest as a promising candidate for future memory and computing applications. Particularly, it is believed that memristors can effectively implement synaptic functions and enable efficient neuromorphic systems. Most previous studies, however, focus on implementing specific synaptic learning rules by carefully engineering external programming parameters instead of focusing on emulating the internal cause that leads to the apparent learning rules. Here, it is shown that by taking advantage of the different time scales of internal oxygen vacancy (VO) dynamics in an oxide‐based memristor, diverse synaptic functions at different time scales can be implemented naturally. Mathematically, the device can be effectively modeled as a second‐order memristor with a simple set of equations including multiple state variables. Not only is this approach more biorealistic and easier to implement, by focusing on the fundamental driving mechanisms it allows the development of complete theoretical and experimental frameworks for biologically inspired computing systems.  相似文献   
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