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991.
A low-voltage electrostatically actuated 2×2 fiber optic switch is achieved using a stress-induced curved polysilicon actuator. The curved polysilicon beam substantially lowers the electrostatic operating voltage of the switch. Large mirror displacement (300 μm) and low operating voltage (20 V) are obtained simultaneously. Sub-millisecond switching time (<600 μs), low optical insertion loss (0.7 dB), and small polarization-dependent loss (0.09 dB) have been achieved 相似文献
992.
We report the measurement of the degenerate fourth-wave mixing (DFWM) of new dithienylethylenes in chloroform solutions at λ=532 nm in ps regime with different numbers of π-conjugated bonds. From these measurements, we evaluated the values of the second order hyperpolarizabilities γ, which are about 103 larger than the γ value of CS2. The influence of π-conjugated bonds on the third-order susceptibilities and appropriate figures of merits is discussed. The more important seems to be the possibility of a simultaneous increase of the third-order susceptibilities, together with the decrease of the absorption coefficients that open a possibility of their use as promising materials for laser wavelengths mixing. 相似文献
993.
Efficient video summarization leads to facilely exploring video content appropriate to the user’s intention with low cognitive demand. In this paper, we present a novel approach for summarizing videos in the form of multi-scale structures that exhibit different video features at different scale levels and allow exploration of video contents with multi-scale interaction. The semantic relationship between structures is addressed and user intention is also considered and integrated in the summarization and interaction. This paper first introduces the concept of multi-scale structures for summarizing video content and describes three different types of structures that present important features at different scale levels. Furthermore, a continuous zooming interaction for browsing multi-scale structures is provided to facilitate video browsing. Finally, an elaborate user study is conducted showing that user performance on understanding and browsing videos is improved. 相似文献
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997.
Van Son Nguyen Laurent Badie Emmanuel Lamouroux Brice Vincent Fabrice Domingues Dos Santos Maëlen Aufray Yves Fort Didier Rouxel 《应用聚合物科学杂志》2013,129(1):391-396
Piezoelectric films were prepared by incorporation of lithium niobate (LiNbO3) nanoparticles into copolymer of vinylidene difluoride and trifluoroethylene. Nanoparticles of LiNbO3 with ferroelectric phase were successfully synthesized and dispersed homogenously by ultrasonication in the copolymer matrix without any surfactant or surface functionalization. The nanocomposites were fully characterized by electronic microscopy, X‐ray diffraction, differential scanning calorimetry, dynamical mechanical analysis, and piezometer. Surprisingly, the copolymer matrix crystallinity and morphology were not affected by the incorporation of nanoparticles. Therefore the nanocomposites remained good mechanicals properties and high ferroelectricity coupled to nonlinear optical activity thanks to the noncentro symmetric space group of lithium niobate. This could be a novel approach to develop new multifunctional materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
998.
Jayaprakash Sivasamy Teck-Neng Wong Nam-Trung Nguyen Linus Tzu-Hsiang Kao 《Microfluidics and nanofluidics》2011,11(1):1-10
This paper reports the findings of a numerical investigation on the droplet break-up in a microfluidic T-junction. The numerical
flow visualization of the droplet formation process is validated with the experimental flow visualization. From the computational
results, we show that the pressure profile of the dispersed phase and the continuous phase in the squeezing regime changes
as the droplet break-up process proceeds. The assumption taken by other researchers that the dispersed phase pressure profile,
during the droplet formation process at a T-junction, remains constant and only the continuous phase pressure changes according
to the blockage of the channel is proved to be invalid. We provide new insights on the pressure difference between the dispersed
phase and the continuous phase during the droplet break-up process and show that the minimum pressure difference happens at
the last moment of the droplet break-up and not during the second and third stage of the droplet formation mechanism in the
squeezing regime as suggested by other researchers. 相似文献
999.
Heng Wu Wenming Liu Qin Tu Na Song Li Li Jianchun Wang Jinyi Wang 《Microfluidics and nanofluidics》2011,10(4):867-876
Microfluidic systems provide a powerful platform for biological analysis and have been applied in many disciplines. However,
few efforts have been devoted to plant cell study. In this article, an optimized culture of tobacco mesophyll protoplasts
and their first polyethylene glycol-induced fusion in a microfluidic device are presented. Culture medium optimization and
dynamics of protoplast growth including size change, organelle motion, and cell mass formation were also investigated microscopically
in real-time. On-chip protoplast culture showed that the first division percentage of tobacco mesophyll protoplasts could
be improved as high as up to 85.6% in 5 days using NT1 medium, and the percentage of small cell mass formation was more than
48.0% in 10 days. Meanwhile, chemical-induced fusion of tobacco mesophyll protoplasts was realized in 3–5 min and a 28.8%
fusion rate was obtained, which was similar to the conventional fusion in a macro-scale environment. These results will be
helpful for the development of microfluidics-based studies on manipulation and analysis of plant cells in a miniaturized environment,
including cell growth and differentiation, gene isolation, and cloning. 相似文献
1000.
The feasibility of using graphite foam as a heat sink and heat spreader in optoelectronic packages is assessed. A “supercooler” is designed, fabricated, and tested to verify its cooling capability under high heat flux conditions in a typical optoelectronic package. The supercooler uses graphite foam as a primary heat transfer material. Water is soaked into the graphite foam, and under evacuated pressure, boiling is initiated under the heating region to provide enhanced cooling. Experiments were conducted for a heat flux of up to 400 W/cm2 deposited over a heating area of 0.5 mm × 5 mm. Two-dimensional transient temperature distributions were recorded using a high-speed infrared camera. Data were obtained for steady heating, and for periodic heating with frequency up to 8 Hz. Results show that the supercooler is very efficient in dissipating heat away from the heating region. The average cooling rate during the cooling period exceeds 170 K/s. 相似文献