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1.
James A. Chiddix 《International Journal of Communication Systems》1989,2(2):87-93
This paper updates a scenario for the evolutionary integration of optical fibre transmission technology into existing cable television networks first presented in 1988. The resulting ‘fibre backbone’ yields a hybrid fibre/coaxial network with significantly better reliability and transmission quality than present systems. System and electro-optical component advances in the last year are reviewed, and the merits of various modulation techniques are examined. The fibre backbone approach emphasizes continuing the broadband delivery of a large number of video signals to the consumer. 相似文献
2.
利用引进的制造技术和设备,制作出了 APT(STLRI)—1.78型系列化光纤连接器。 相似文献
3.
Shear Bombs in Fibre Composites Despite an optimum external shape non‐load adapted internal fibre orientation can lead to the formation of shear cracks where crossing tension‐compression principal stress trajectories create localized shear peaks. Trees are subject to those failure because they cannot re‐arrange their fibres after wood formation. Bones can adjust their micro‐structure to changing load conditions and in this way can better control shear failure. The engineer working with fibre composites should be alert to avoid fibre arrangements not following the force flow. Localized shear zones may also form near notches similar to normal notch stresses, however they are not always situated at the contour line of the notch. 相似文献
4.
Gr(C)纤维增强镁基复合材料的界面结构 总被引:4,自引:5,他引:4
采用真空—压力浸渗工艺制备Gr(C)/Mg复合材料,Gr/Mg材料界面上无化学反应迹象,有析出物γ相(Mg17Al12),该析出物形状、大小与制备工艺条件,主要是纤维预制件温度有关。C/Mg复合材料界面Al含量较基体高出2倍多,文中分析了可能的原因 相似文献
5.
A new type of three-phase thermoplastic composite has been made, consisting of a main reinforcing phase of woven glass or carbon fibres and a PA6 nanocomposite matrix. Nanocomposites have the potential to improve the matrix dominated flexural and compressive strength by increasing the matrix modulus. Good quality fibre composites have been made with several types of PA6 nanocomposite and unfilled PA6 in combination with glass and carbon fibre reinforcement. Flexural tests on commercial PA6 fibre composites have shown the decrease of the flexural strength upon increasing temperature and this has been compared with the decrease of the matrix modulus. The nanocomposites used in this research have moduli that are much higher than unfilled PA6, also above Tg and in moisture conditioned samples. The strength of glass fibre composites can be increased by more than 40% at elevated temperatures and the temperature range at which a certain minimum strength is present can be increased by 40-50 °C. Carbon fibre composites also show significant improvements at elevated temperatures, although not at room temperature. The advantage of the use of nanocomposites instead of other polymers to improve the fibre composite properties is that the properties can be improved without any change in the processing conditions. 相似文献
6.
7.
用挤压铸造方法制备Mullite/Al-Cu-Si复合材料。用分析透射电镜(ATEM)观察了复合材料的微结构及微成分。结果表明:莫来石(Mullite)纤维由大小不、位相不同、分布不均的细小晶粒组成:在淬火态“纤维/基体”界面和“Si晶体/基体”界面附近基件一侧中.都可发现高密度位错的存在;在Si含量较高的情况下,Mullite/Al-Cu-Si复合材料界面处没有发现界面产物的存在,而在纤维/基体界面处析出非平衡共晶θ(Al,Cu)相。 相似文献
8.
冯维元 《电脑编程技巧与维护》2011,(6):46-48,76
从数据备份系统结构的角度,研究了传统数据备份技术的优缺点,针对现有备份技术的存在的问题,通过在存储区域网络中引入网络数据管理协议,使得存储区域网络环境下的数据备份极大减轻了网络负载量,同时业务服务器最大限度地从数据备份过程中解脱出来,从而提高了整个备份系统的性能;同时对基于存储区域网络数据备份技术研究的特点、存在的问题、研究热点和应用情况等进行了分析。 相似文献
9.
Cylindrical fibre actuators have been constructed by a coextrusion method using a thermoplastic polyurethane wall and a conductive grease filler. These actuators may be operated as single fibres or bundled together as actuating ropes. Key results include the validation of Carpi’s wall pressure model [F. Carpi, D.D. Rossi, Dielectric elastomer cylindrical actuators: electromechanical modelling and experimental evaluation, Mater. Sci. Eng. C-Biomimetic Supramol. Syst. 24 (2004) 555–562] and the proof-of-concept demonstration of a technique that can be used for producing inexpensive dielectric elastomer actuators on an industrial scale. 相似文献
10.
An investigation showing the performance of compact long period grating (LPG) pairs under demanding experimental conditions, making comparisons with the use of single LPGs for the simultaneous measurement of strain and temperature is presented. In this work, a LPG pair (LPGP) sensor comprising two weak (2.5 dB each) LPGs, 13 mm apart, was compared against the performance of two single LPG sensors (LPG1 & LPG2) with coupling strengths of 2.5 dB and 12.5 dB, respectively. All the LPG sensors used were subjected to extreme conditions arising from the fabrication, by choosing a high amplitude mask period with short physical length LPGs, and the high temperature annealing processes. In addition, a low resolution detection instrument was used to capture the spectra under study. Results have shown that the LPGP is 40 times better than the first single LPG used (LPG1) and three times better than the second LPG (LPG2). Using the error analysis methodology of Brady et al., the temperature and strain errors due to the uncertainty of the wavelength measurement for each of the LPG1, LPG2, and LPGP were compared with the typical performance of various fibre Bragg grating (FBG)-based sensor schemes under similar testing conditions. It was found that LPGPs offer the best performance especially when using low resolution detection instrumentation. 相似文献