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This paper theoretically studies the double-pumped fibre-optical
parametric amplifiers (FOPAs) in photonic crystal fibres. Two
distinct working regimes of FOPAs are researched, which depend on the
dispersion at the central wavelength of the two pumps. Extremely
broad tuning range can be obtained when the central pump wavelength
is in the normal dispersion regime and is insensitive to the
wavelength separation between the two pumps, while the tuning range
is narrow in the anomalous dispersion regime and can be significantly
enhanced by increasing the wavelength separation. Impacts of
higher-order dispersions and temporal walk-off on the gain spectra
are also discussed. 相似文献
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介绍防音型机组和移动式机组等特殊用途柴油发电机组的技术现状和发展展望,以及这一类型机组在挂车电站及汽车电站上的应用。 相似文献
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Influence of spatiotemporal coupling on the capture-and-acceleration-scenario vacuum electron acceleration by ultrashort pulsed laser beam 下载免费PDF全文
This paper investigates the properties of the ultrashort pulsed beam aimed to the
capture-and-acceleration-scenario (CAS) vacuum electron acceleration. The result
shows that the spatiotemporal distribution of the phase velocity, the longitudinal
component of the electric field and the acceleration quality factor are
qualitatively similar to that of the continuous-wave Gaussian beam, and are slightly
influenced by the spatiotemporal coupling of the ultrashort pulsed beam. When the
pulse is compressed to an ultrashort one in which the pulse duration TFWHM
<5T0, the variation of the maximum net energy gain due to the
carrier-envelope phase is a crucial disadvantage in the CAS acceleration process. 相似文献
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针对可信平台模块(TPM)访问受重放攻击和替换攻击威胁的问题,提出一种改进的TPM访问控制方法.首先建立TPM长期访问控制功能,通过创建额外授权数据以保证进程结束后继续授权会话,同时将TPM地址与Domain U的身份标识号相关联,以保护其地址免受替换攻击.其次,建立TPM所有权共享功能,允许多个DomainU使用相同的TPM地址并防止死锁,因共享地址不能被重写,可保护敏感数据免受攻击.最后基于Xen实现了该方法并评估了其性能.实验结果证明了该方法的可行性和有效性,TPM访问性能开销在可接受的范围内. 相似文献
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Android是现在最受欢迎的移动平台操作系统之一。它最大的特点就是源代码开源,因此吸引了很多行业领先企业,包括通信运营商、设备制造商、芯片制造商等各类企业,同时也吸引了大量用户。根据市场研究公司IDC发布的数据,截止2012年第二季度,Android的市场份额高达68.1%。为了使Android用户不受病毒的危害,本文分析了Android平台下的病毒攻击原理,提出了一个基于Android的安全防御系统的解决方案,并进行了实现和测试,可以查杀病毒,自动监控设备。测试结果表明,系统能够有效监测到病毒的入侵并及时采取措施。 相似文献
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本文主要阐述了近代电子技术在航空领域的新应用,特别是计算机技术,大规模集成电路、可见技术和光电技术的应用,将使航空领域产生飞跃性发展。 相似文献