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In this study, poly(ethylene terephthalate) (PET)/SiO2 nanocomposites were synthesized by in situ polymerization and melt‐spun to fibers. The superfine structure and properties of PET/SiO2 fibers were studied in detail by means of TEM, DSC, SEM, and a universal tensile machine. According to the TEM, SiO2 nanoparticles were well dispersed in the PET matrix at a size level of 10–20 nm. The DSC results indicated that the SiO2 nanoparticles might act as a marked nucleating agent promoting the crystallization of the PET matrix from melt but which inhibited the crystallization from the glassy state, owing to the “crosslink” interaction between the PET and SiO2 nanoparticles. The tensile strength of 5.73 MPa was obtained for the fiber from PET/0.1 wt % SiO2, which was 17% higher than that of the pure PET. The fibers were treated with aqueous NaOH. SEM photographs showed that more and deeper pits were introduced onto PET fibers, which provided shortcuts for disperse dye and diffused the reflection to a great extent. According to the K/S values, the color strength of the dyeing increased with increasing SiO2 content. It is found that the deep dyeability of PET fibers was improved greatly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
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《Inorganic chemistry communications》2007,10(4):467-470
The complex [Cd2(phen)4(p-phth)(H2O)2](p-phth) · 10H2O (1) has been synthesized by the reaction Cd(NO3)2 with phen and p-phth (where phen = 1,10-phenanthroline, p-phth = p-phthalic acid) in a solution of ethanol and distilled water. The crystal structure was characterized by X-ray single-crystal diffraction and infrared spectrum. In 1, a novel 2D supramolecular structure was formed, containing water octamer and tetramer. 相似文献
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为扩大流速传感器的测量范围并降低功耗,制造并测试了一种基于自加热非晶锗薄膜热电阻的MEMS流速传感器,它是由嵌入氮化硅薄膜的四个非晶锗热敏电阻和一对环境测温补偿电阻组成。四个非晶锗热电阻同时作为自加热热源和测温元件,相互连接以形成惠斯通电桥。给出了MEMS工艺流程,微加工制造了尺寸为8.9 mm×5.6 mm×0.4 mm的流速传感器芯片。搭建了低流速和高流速气流通道实验装置,对传感器的惠斯通电桥施加50μA的恒定电流(CCA),实现了0~50 m/s范围内的流速测量。结果表明,传感器在低流速(0~2 m/s)时的灵敏度约为81.6 mV/(m/s),在高流速(2~50 m/s)时的灵敏度约为51.9 mV/(m/s),最大功耗仅约为1.03 mW。 相似文献
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CHEN KenLe & ZHANG JinWen National Key Laboratory of Micro/Nano Fabrication Technology 《中国科学:信息科学(英文版)》2011,(2)
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Yi-Bo Wu Juang Wang Chun-Ping Yan Sheng-Ping Mao Cong-Chun Zhang Hong Wang Gui-Fu Ding 《Microsystem Technologies》2010,16(11):1869-1879
Bistable micro mechanisms are gaining great attention in MEMS applications. This paper presents the mechanical modeling and
experimental characterization of a bistable torsion/cantilever micro latching mechanism for performing low power bistable
relay applications. The bistable micro mechanism consists of two cantilevers which form symmetrical rocker levers. The free–free
cantilever is suspended by a diamond skeleton which in turn is attached to a torsion cantilever. A permanent magnet is placed
beside for holding the closed state with a permalloy soft magnetic circuit. The special diamond support is designed to enhance
the stiffness of the overhang beams. In order to deduce the spring stiffness of system, a mechanical modeling of the leveraged
torsion/cantilever system was performed by Castigliano’s theorem. Meanwhile, the magnetostatic latching force was also deduced
by the Maxwell electromagnetism theory. Then the device has been prepared by a laminated copper sacrificial layer process.
This process can facilitate the fabrication complexities of traditional magnetic device with coil structures. Finally, mechanical
performance was characterized by an atomic force microscopy, combined with finite element simulation using ANSYS™ package and analysis model as well. Two stable states of the micro mechanism were hold successfully with no power consumption
by interferoscope profilometry of WYKO optical profiling system. 相似文献
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We present an analytical framework for the performance analysis of CSMA/CA based wireless mesh networks. This framework can provide an accurate throughput-delay evaluation for both saturated and unsaturated cases. An efficient algorithm that determines the collision domain for each node based on both the interference range and routing in the network is presented. As another important application of this framework, we develop an analytic model that enables us to obtain closed form expressions for delay in terms of multipath routing variables. A flow-deviation algorithm is used to derive the optimal flow over a given set of routes for any number of classes. The model takes into account the effects of neighbor interference and hidden terminals, and tools are provided to make it feasible for the performance analysis and optimization of large-scale networks. Numerical results are presented for different network topologies and compared with simulation studies. 相似文献