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并行FFT是解决大数据量FFT运算耗时过久的重要途径,在PC机群上实现并行FFT是一种低成本、高效率的解决方案。本文讨论了PC机群环境下MPI并行FFT实现,并利用建立的平台,对并行算法进行了测试,得出了一些有意义的结论和方法。 相似文献
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Haiqing Yin Wenbin Cao Y. Miyamoto 《北京科技大学学报(英文版)》2006,13(5):461-464
A novel process, which was based on powder injection molding, was investigated for the fabrication of ceramic photonic bandgap structure with three-dimensional diamond lattice. The SiO2-TiO2 ceramic powder was mixed with a water-soluble agent to produce slurry. The slurry was then injected into an epoxy mold with inverse diamond lattice, fabricated by the stereolitographic rapid prototyping process. To increase the density of the green compact, cold isostatic pressing was applied on the unit. Using thermal debinding, the water-soluble agent and the epoxy were extracted at 360 and 650 K, respectively. Sintering was immediately done at 950 K for 5 h and the desired three-dimensional ceramic structure was obtained. The calculated band diagram for this structure indicated the existence of an absolute photonic bandgap for all wave vectors. At 14.7-18.5 GHz, a complete band gap was located with a maximum attenuation of 30 dB at 17 GHz, when transmission was measured in the 〈100〉 direction between 10 and 20 GHz. 相似文献
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We report on the synthesis, characterization and optical properties of barium strontium titanate (BST) quasi photonic crystals (PCs) through a sol–gel technique with the porous alumina template (PAT). The structure, morphology and pore-size distribution of the samples were characterized by SEM, XRD and EDS, The Ba0.6Sr0.4TiO3 PCs of crystalline cubic phase with uniform pore size and ordered arrange were successfully synthesized. The obtained quasi BST PCs not only show that the nanostructure has spatially periodical orderly arrangement, but also exhibit good optical transmittance properties. The advantage of this sol–gel technique with PAT to fabricate ferroelectric (FE) nanopore arrays lies in its low cost and simplicity. This study opens a pathway for the effective fabrication and studies of FE nanopore arrays in uniquely large area. 相似文献
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G. Pennazza C. Fanali M. Santonico L. Dugo L. Cucchiarini M. Dachà A. D’Amico R. Costa P. Dugo L. Mondello 《Food chemistry》2013
The characteristic aromatic composition of white truffles (Tuber magnatum Pico) determines its culinary and commercial value. However modifications of truffle organoleptic proprieties occur during preservation. A study of headspace of white truffles by using Electronic nose (E-nose), gas chromatography–mass spectrometry (GC–MS) and sensory analyses was performed. Truffles were stored at different conditions for 7 days: +4 and +8 °C wrapped in blotting paper or covered by rice or none of the above. Headspace E-nose measurements and sensory analyses were performed each day. Statistical multivariate analysis of the data showed the capability of E-nose to predict sensorial analysis scores and to monitor aroma profile changes during storage. Truffle’s volatile molecules were also extracted by headspace solid phase microextraction technique and separated and identified by GC–MS. Partial Components Analysis of data was performed. E-nose and GC–MS results were in agreement and showed that truffle storage in paper at +8 °C seemed to be the best storage condition. 相似文献
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A.L.S. King A.M. Valença A.C.O. Silva T. Baczynski M.R. Carvalho A.E. Nardi 《Computers in human behavior》2013
Background
The increasing use of new technologies and virtual communication involving personal computers (PCs), tablets and mobile phones are causing changes in individuals’ daily habits and behavior. We report the case of an individual with social phobia who developed a dependency on communication through virtual environments (i.e., nomophobia), and used a PC as a form of relating to the outside world to reduce stress and to avoid direct social relations. Nomophobia refers to the discomfort or anxiety caused by the non-availability of a mobile phone, PC or any another virtual communication device. Social phobia is described as an anxiety disorder of chronic evolution.Objective
To study nomophobia as a manifest behavior that might serve as an indication of a possible anxiety disorder.Methodology
The treatment consisted of the use of medication, cognitive-behavioral therapy (CBT) and the application of evaluation tools (interviews, scales, inventories and questionnaires).Results
The individual responded satisfactorily to medication and CBT treatment, which reduced his time using the PC and increased his exposure to real-life situations.Conclusion
Nomophobic behavior produces changes in daily habits and can reveal other aspects to be investigated, such as the presence of comorbid mental disorders. 相似文献8.
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红外成像系统仿真技术的现状与未来 总被引:12,自引:3,他引:9
利用计算机进行红外成像系统的仿真有助于系统的整体设计,同时也是评价系统性能的有力工具。人们在这一领域做了大量工作,并取得了良好的效果。 文中概述了红外成像系统计算机仿真技术所采取的重要技术路线、研究方法和研究成果的现状,介绍并比较了现有的几个典型仿真模型,并提出了几点看法。 相似文献