排序方式: 共有17条查询结果,搜索用时 15 毫秒
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J. Lawry A. Ray D. Klimesch P. Thomas J.-P. Guerbois J. Harrison 《Journal of Thermal Analysis and Calorimetry》2005,80(3):637-641
Summary Due to growing environmental concerns and the need to use less energy-intensive building products, alternatives and improvements to Portland cement (PC) are being actively researched worldwide. Use of supplementary materials is now a common practice where PC is the predominant component of inorganic building products. This study aims to investigate the potential of magnesia (MgO), derived from a naturally occurring raw material magnesite, as a supplementary material. Results from mortar samples prepared with 10 and 20% replacements of ordinary Portland cement (OPC) by MgO are presented. DTA-TG was used to study and characterise the hydration behaviour of MgO in OPC environment after 3, 7, 14, 28, 56 and 90 days of moist curing. Microstructural and compressive strength determinations providing additional information on the influence of hydrated phases are also reported. 相似文献
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此篇论文将介绍一个用于半导体光罩上图样设计以及可用于实际生产的光刻反向计算技术(ILT)。在论文中将讨论有关ILT的最新发展,包括在超成像极限协助图样(SRAF)的生成,可增加制程宽容度的ILT,以及如何生成满足光罩生产标准的图样等方面。从内部的研究结果和客户的使用结果可以看出,ILT已经不再只是一种用于研究的工具,而是已经可以用于先进半导体制程的大规模生产。在对各个环节优化之后,ILT可以增加制程的宽容度,同时将光罩的成本控制在可以接受的水平。 相似文献
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光纤通信系统中基于光学相位共轭和预啁啾的色散及非线性补偿研究 总被引:2,自引:0,他引:2
采用光学相位共轭补偿光纤通信系统的色散及非线性必须满足一个前提条件,即相位共轭器两边线路上的色散和非线性分布(或传输功率分布)必须严格对称,这在现有的一般传输线路(标准单模光纤加集总掺铒光纤放大器)难以实现。提出了预啁啾结合中距相位共轭的补偿方案,并进行了数值计算。结果表明,通过在发送端对输入脉冲进行预啁啾展宽,可有效地减轻非线性效应与色散的相互作用,获得理想的补偿效果;对于皮秒超短光脉冲传输,脉冲内拉曼散射相对于三阶色散对补偿结果的影响很小,因此,频域相位共轭相对于时域相位共轭具有更好的综合补偿性能。该方案简单易行,无需对已敷设好的线路作较大改动。 相似文献
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Charu Narula 《Optik》2011,122(11):941-944
The effectiveness of the conventional dispersion compensation techniques: DCF, FBG and OPC to use with soliton transmission is presented. The frequency shifts of solitons induced by collisions between different channels in a soliton WDM system can be reduced by dispersion compensation. The reduction mechanism applied is the cancellation of the shifts generated in both normal and anomalous dispersion regimes. It is analyzed that phase jitter can be reduced by the use of midway spectral inversion. 相似文献
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Computational aeroacoustics requires numerical techniques capable of yielding low artificial dispersion and dissipation to preserve the amplitude and the frequency characteristics of the physical processes. Furthermore, for engineering applications, the techniques need to handle irregular geometries associated with realistic configurations. We address these issues by developing an optimized prefactored compact finite volume (OPC‐fv) scheme along with a Cartesian cut‐cell technique. The OPC‐fv scheme seeks to minimize numerical dispersion and dissipation while satisfying the conservation laws. The cut‐cell approach treats irregularly shaped boundaries using divide‐and‐merge procedures for the Cartesian cells while maintaining a desirable level of accuracy. We assess these techniques using several canonical test problems, involving different levels of physical and geometric complexities. Richardson extrapolation is an effective tool for evaluating solutions of no high gradients or discontinuities, and is used to evaluate the performance of the solution technique. It is demonstrated that while the cut‐cell method has a modest effect on the order of accuracy, it is a robust method. The combined OPC‐fv scheme and the Cartesian cut‐cell technique offer good accuracy as well as geometric flexibility. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Franklin M. Schellenberg 《Optical Review》2005,12(2):83-89
Resolution enhancement techniques (RETs) have enabled the adoptin of optical lithography well below the wavelength of the exposing light. Examination of the history of RET and recent developments shows that only 3 of the 4 independent variables available for wavefront engineering have been utilized. This suggest that, with full utilization of polarization and other electromagnetic effects, optical lithography will be the manufacturing technology for ICs for the foreseeable future. 相似文献
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目前,有机光导体(organic photo conductor)大部分采用双层结构,即拥有电荷产生层(CGL)和电荷传输层(CTL)的功能分离型结构。这种结构可有效地降低热激发,暗衰减速度,并能减少单层结构中不同载流子的复合概率。其中CGL一般是将颜料(CGM)微粒分散于高分子树脂内制成,CTL则由树脂中掺人一定量的电荷传输材料CTM(一般为分子级的电子受体或给体)。曝光时,CGL吸收光子产生的电荷(空穴和电子),注人CTL中,在表面电荷产生的电场的作用下,传输至OPC表面,与这部分的表面电荷形成静电潜影。 相似文献