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941.
分析了开发10Gbit/sTransponder模块的必然性,介绍了10Gbit/sTransponder模块的原理、特点和参数指标。并且用开发出的两只40km300脚10Gbit/sTransponder模块成功地进行了43km的无误码传输试验和测试。  相似文献   
942.
The syntheses of polyenynes as model compounds for poly(diacetylene)s (PDAs) are described. Variation of properties (UV–VIS, Raman, NMR and bond geometries) as a function of the chain length was investigated. After extrapolation to infinite chain length these data were compared to those for PDAs. From UV–VIS spectra a value of λ = 551 nm (2.25 eV) was calculated corresponding to the electronic transition of a single polyenyne chain. This energy is located at the low energy end of a yellow PDA solution spectrum. From Raman scattering v(C?C) = 2108–2128 cm?1 and v(C?C) = 1505–1532 cm?1 were calculated after extrapolation. Similarly sp-C13C NMR data yielded a shift of δ = 100 ppm. These data are almost identical to data known for yellow PDA solutions. Bond geometries are almost identical to those of poly(diacetylene)s and theoretical data.  相似文献   
943.
The large-deformation three-dimensional glass-rubber constitutive model for isotropic, amorphous, linear polymers near the glass transition, previously proposed, has been extended to include a spectrum of network relaxations. In addition, an experimental programme of uniaxial tension and compression tests was carried out on high molecular weight cast sheets of poly(methyl methacrylate) (PMMA), with varying strain-rate and temperature across the range from 114 to 190 °C, encompassing the thermoforming range of practical importance. The extended model was found to fit successfully the data for PMMA, provided a doublet network relaxation spectrum was employed. The original model, with only a single network relaxation, was found to be grossly inadequate when there was significant network relaxation by entanglement slippage. Parameters of the model for PMMA, obtained by fitting to the new data, were compared with values obtained by other routes.  相似文献   
944.
Ionomeric composites based on sepiolite and hydrogenated poly(styrene butadiene) block copolymer were obtained and characterized from a microstructural and electrical point of view. Before blending, because of the high silanol group concentration in the sepiolite, the latter could be organophilized with suitable coupling agents. The resulting materials were easily processed into thin films or membranes 0.2–0.4 mm thick, their conductivity in some cases approaching 10?1 S/cm. Their suitability for film formation and good electrical properties indicate potential applications as electrolytes in polymer fuel cells. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3512–3519, 2002  相似文献   
945.
未来十年综合航电系统的发展趋向   总被引:4,自引:4,他引:0  
汪桂华 《电讯技术》2002,42(6):23-26
本文主要阐述未来十年国外综合航电系统的总的发展趋向,重点介绍了在开放式系统结构的研究与应用、采用COTS技术、模块化、多传感器综合技术等方面的发展趋向。  相似文献   
946.
SynthesisandSpectralPropertiesofMixedLigandComplexesofLanthanidePerchloratewithBis(phenylsulfinyl)ethaneandOrganicLewisBase...  相似文献   
947.
空气中^131I的取样和测量方法的研究   总被引:5,自引:2,他引:3  
哈继录  张超 《辐射防护》1992,12(4):260-265
本文介绍一种气态和气载~(131)I 取样器。着重介绍了一种指数分布源的效率刻度方法,讨论了与取样有关的一些问题。  相似文献   
948.
Novel hydrogen-bonded acidic fluorinated poly(amide-imide-silica) hybrid materials, FPAI-SiO2 (6E and 6F) series, were synthesized by a sol-gel process. The structures and spin relaxation of the hybrids were characterized by infrared (IR), and 29Si and 13C nuclear magnetic resonance (NMR) spectroscopy. The abundant Q4 structures implied that in free catalyst the degree of condensation of tetramethoxysilane was enhanced by hydrogen-bonded acidic fluorinated poly(amide-imide). The dynamics on the local mobility of the hybrids was investigated by the time constant for energy exchange between 1H and 29Si spin system (TSiH) and spin-diffusion path length (L) measurements. It was found that the faster TSiH of 6E and 6F hybrids compared with the previous study of similar 6C and 6D hybrids implied that 6E and 6F hybrids had more aggregated structures even though the organic terminal segment changed from rigid imide to more flexible amide. The interactions of the charge transfer between donor and acceptor molecules or π-π aromatic stacking may be the dominant factors to affect the structures of 6E and 6F hybrids. Moreover, M1 and D2 segments of 6F hybrids had the same level mobility and the mobility of the 6F hybrids was little improved as the soft and flexible 1,3-bis(3-aminopropyl)-tetramethyl-disiloxane segment was incorporated in the dense structures of 6F hybrids. All of the L values of 6E and 6F hybrids were on the scale of 3.5-4.0 nm. The result also suggested that 6E and 6F hybrids had similar denser structures as 6D hybrids.  相似文献   
949.
针对陕甘宁盆地低渗透气田天然气井地层漏失等问题,通过室内试验,设计了密度为1.41~1.60g/cm3的二级固井高炉矿渣——MTC水泥浆和APIG级水泥——MTC水泥浆。目的提高固井质量、降低固井成本。结果通过对高炉矿渣的水化机理和两种MTC水泥浆对比分析,认为高炉矿渣——MTC转化法较APIG级水泥——MTC转化法,具有外加剂用量少、抗压强度高、体系简单、固井成本低等特点。结论两种低密度MTC水泥浆配方设计合理,性能优良,能满足现场施工的要求。  相似文献   
950.
Although the gas metal arc welding (GMAW) process is widely used for joining metals, its planning is still a cumbersome task. The planning procedure involves many complex interrelationships among the process variables and depends heavily on empirical knowledge. Therefore, a solution method that allows a convenient way to represent the domain knowledge and evaluate the process variable relationships is needed. Further, the lack of a strong domain theory to quantify these interrelationships is a deficiency in the planning of the GMAW process. This paper presents a solution method that overcomes this deficiency and introduces a convenient knowledge representation scheme. The solution method considers the planning procedure to be a constraint satisfaction problem (CSP). The AC-4 algorithm is used to obtain arc consistency among nodes in the constraint network and the PC-4 algorithm is applied to obtain path consistency in the network. A modified version of the AC-4 algorithm is developed to reduce the search space and correspondingly reduce the computation time. An example is presented to demonstrate the capability of the method and its potential to reduce lead time.  相似文献   
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