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将一定比例的Cu、石墨、SnO2粉末混合装入7根纯铜管内,封口后再以密排方式装入一银管中。采用多次挤压-拉拔连续纤维复合工艺制备出了Ag-Cu-C-SnO2复合触头材料。用金相显微镜观察了材料组织结构,测试了材料的机械性能、电性能等,并进行了寿命试验。结果表明,多次挤压一拉拔工艺可以制备连续纤维化的Ag-Cu-C-SnO2复合材料,其接触电阻稳定,有较好的抗熔焊性和抗电弧烧损性。材料经直流28V,40A电负荷下,工作寿命之在3000次以上,可在大、中负荷下的多种继电器、接触器上得到应用。 相似文献
76.
Anthony Mshandete Lovisa Bjrnsson Amelia K. Kivaisi M.S.T. Rubindamayugi Bo Mattiasson 《Renewable Energy》2006,31(14):2385-2392
The degradation and biogas production potential of sisal fibre waste could be significantly increased by pre-treatment for reduction of particle size. Batch-wise anaerobic digestion of sisal fibre waste was carried out in 1-l digesters with fibre sizes ranging from 2 to 100 mm, at an ambient temperature of 33 °C. Sediment from a stabilisation pond at a sisal production plant was used as starter seed. Total fibre degradation increased from 31% to 70% for the 2 mm fibres, compared to untreated sisal fibres. Furthermore, the results confirmed that methane yield was inversely proportional to particle size. Methane yield increased by 23% when the fibres were cut to 2 mm size and was 0.22 m3 CH4/kg volatile solids, compared to 0.18 m3 CH4/kg volatile solids for untreated fibres. By anaerobic digestion and biogas production, the 148,000 tonne of waste sisal fibres generated annually in Tanzania could yield 22 million m3 of methane, and an additional 5 million m3 of methane if pre-treatment by size reduction to 2 mm was applied. 相似文献
77.
Tundong Liu Linjing Liu Jing Chen Hao Jiang Qiao Sun 《Journal of Modern Optics》2018,65(14):1680-1687
This paper introduces an evolutionary algorithm, Shuffled Frog Leaping Algorithm (SFLA), to solve the optimization problem in designing the multi-pumped Raman Fibre Amplifier (RFA). SFLA is a powerful optimizer tool because of its efficient mathematical expressions and global search capability. We utilize SFLA to determine the optimal pump wavelengths and pump powers by minimizing the gain ripple of RFA. To accelerate calculations, a terminal value optimization strategy (TVOS) is incorporated into the evolution of SFLA. This proposed strategy takes the terminal power values of pumps as the decision variables in optimization. Then, the optimal original power values of the pumps are obtained by solving the Power Coupled Equations once, without using the traditional method of repetitive guesses.The combination of SFLA and TVOS enhances the efficiency of optimization and accelerates calculation, while satisfying the design requirements of RFA.The simulation results show that nearly 65% of computational time has been saved compared with the traditional average power analysis. The 4-pumped C+L band of backward multi-pumped RFA with the average net gain of 0 dB, 1 dB and 2 dB are designed individually, where the gain ripple is less than 0.64 dB. The combination of SFLA and TVOS enhance the optimization efficiency and improve the performance of RFA with good gain profile. 相似文献
78.
A wide-band, passively Q-switched fibre lasers based on ytterbium- and thulium-doped fibre gain medium are proposed and demonstrated. The lasers employ a transition metal dichalcogenide, tungsten sulphoselenide as a saturable absorber (SA) which is prepared by mechanical exfoliation technique. By integrating the SA in the laser cavities, self-starting Q-switched at 1038 and 1982?nm are obtained. The generated pulses exhibit a microsecond pulse duration with few kilohertz repetition rate. The proposed SA has high potential as a new material to cater to the needs of various scientific, industrial and biomedical applications. 相似文献
79.
Divertor plasma-facing components of future fusion reactors should be able to withstand heat fluxes of 10-20 MW/m2 in stationary operation. Tungsten blocks with an inner cooling tube made of CuCr1Zr, so-called monoblocks, are potential candidates for such water-cooled components. To increase the strength and reliability of the interface between the W and the cooling tube of a Cu-based alloy (CuCr1Zr), a novel advanced W-fibre/Cu metal matrix composite (MMC) was developed for operation temperatures up to 550 °C. Based on optimization results to enhance the adhesion between fibre and matrix, W fibres (Wf) were chemically etched, coated by physical vapour deposition with a continuously graded W/CuPVD interlayer and then heated to 800 °C. The Wf/Cu MMC was implemented by hot-isostatic pressing and brazing process in monoblock mock-ups reinforcing the interface between the plasma-facing material and the cooling channel. The suitability of the MMC as an efficient heat sink interface for water-cooled divertor components was tested in the high heat flux (HHF) facility GLADIS. Predictions from finite element simulations of the thermal behaviour of the component under loading conditions were confirmed by the HHF tests. The Wf/Cu MMC interlayer of the mock-ups survived cyclic heat loads above 10 MW/m2 without any damage. One W block of each tested mock-up showed stable thermal behaviour at heat fluxes of up to 10.5 MW/m2. 相似文献
80.
N. Endstrasser B. Rasul K. Krieger P. Scheier 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(4):700-703
Sticking coefficients of deuterium from are quantified on fusion relevant plasma sprayed tungsten and carbon fibre composite in the incident energy range from about 0-100 eV. The samples that were cut from ASDEX-Upgrade tiles are exposed to a beam of of specific incident energy, Einc, in the tandem mass spectrometer BESTOF in Innsbruck. Nuclear reaction analysis is performed ex-situ at IPP Garching for the quantification of deuterium content. The deuterium content difference measured on a spot before and after ion-beam exposure of the sample is assigned to the above mentioned species of hydrocarbon molecules sticking on the surface, allowing the calculation of the sticking probability of a specific deuterated molecular ion. The sticking coefficient, S, is found to depend on the incident energy and shows a maximum of about S ∼ 0.4 around Einc = 30 eV on CFC and about S ∼ 0.1 near Einc = 20 eV in case of PSW. 相似文献