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51.
纤维表面处理对植物纤维增强水泥的物理力学性能影响 总被引:2,自引:0,他引:2
植物纤维增强水泥的力学性能具有湿敏感性,随湿度增加弯曲强度下降幅度较大。本文工作采用的几种浸渍处理纤维表面的方法,有效地改善了这种状况,其中一种经处理的纤维增强水泥较没有处理的对比试样在饱水状态下的弯曲强度提高了67%,气干状态提高了18%,缩小了二者间的差距。 相似文献
52.
Suely P. Freitas Fernando C. Da Silva Regina C. A. Lago & Raad Y. Qassim 《International Journal of Food Science & Technology》1996,31(4):319-325
Shear rate vs. shear stress data were obtained on avocado pulp in water emulsions using a concentric cylinder rheometer and fitted to a power law model. Dilution, as volume fraction of water, had a pronounced effect on the apparent viscosity of the pulp emulsions and the Richardson equation, (ηR = exp.( a φ) for the emulsion viscosity fitted the data well. A mean slope coefficient, a , of 4.57 can be used as a first approximation. Enzymatic treatment (40°C, 1 h), is slightly more effective than thermal treatment (65°C, 1 h), in reducing the initial apparent viscosity of the pulp-water emulsions 相似文献
53.
计算机网络的发展日新月异。下一代计算机网络(NGN)的探讨、研究已经成为当前的潮流。下一代网络是目前电信、互联网运营商和设备厂商都在讨论的热点技术,国内外许多网络运营商都在探讨,并正在或考虑建设试验网进行更深入的研究。本文介绍了NGN的定义、主要特点、分层结构和关键技术。 相似文献
54.
FTIR spectroscopy was applied to study the initial steps of ethylene polymerization on reduced chromia-silica (0.5 wt% Cr/SiO2). To decrease the speed of the reaction small doses of gas were introduced to the catalyst in each run and C2D4 was used to confirm band assignments. At the initial steps of the reaction only ethylene molecules coordinated to probably Cr
A
2+
cations were observed. The concentration of such complexes was estimated to be about 50% of the total amount of Cr atoms in the sample. The FTIR spectrum of the polymer formed at the initial doses of C2H4 (when [C2H4] [Cr]) was found to be slightly different from that formed after excess ethylene was introduced onto the catalyst ([C2H4] > [Cr]). 相似文献
55.
研究了一种制造低电电压氧化锌压敏电阻器的方法。在基本成分的基础上适当加入二氧化钛可降低梯度电压(V1mA/mm),适量掺硼和改进热处理工艺可减小元件的漏电流和提高其稳定性。 相似文献
56.
提高Cr12MoV钢冷作模具寿命的措施 总被引:3,自引:0,他引:3
从原材料改锻、预备热处理、淬火及回火、深冷处理、表面强化处理等方面分析介绍了提高Cr12MoV钢冷作模具寿命的一些方法和措施 ,并通过实例表明 ,采用这些方法和措施可较大幅度地提高模具寿命 相似文献
57.
Chemical looping combustion (CLC) is a clean and efficient flame-free combustion technology,which combust the fuels by lattice oxygen from a solid oxygen carrier with inherent CO2 capture.The develop-ment of oxygen carriers with low cost and high redox performance is crucial to the whole efficiency of CLC process.As the solid by-product from the sulfuric acid production,pyrite cinder presented excellent redox performance as an oxygen carrier in CLC process.The main components in pyrite cinder are Fe2O3,CaSO4,Al2O3 and SiO2 in which Fe2O3 is the active component to provide lattice oxygen.In order to sys-tematic investigate the functions of supports (CaSO4,Al2O3 and SiO2) in pyrite cinder,three oxygen car-riers (Fe2O3-CaSO4,Fe2O3-Al2O3 and Fe2O3-SiO2) were prepared and evaluated in this study.The results showed that Fe2O3-CaSO4 displayed high redox activity and cycling stability in the multiple redox cycles.However,both Fe2O3-Al2O3 and Fe2O3-SiO2 experienced serious deactivation during redox reactions.It indicated that the inert Fe-Si solid solution (Fe2SiO4) was formed in the spent Fe2O3-SiO2 sample,which decreased the oxygen carrying capacity of this sample.The XPS results showed that the oxygen species on the surface of Fe2O3-CaSO4 could be fully recovered after the 20 redox cycles.It can be concluded that CaSO4 is the key to the high redox activity and cycling stability of pyrite cinder. 相似文献
58.
59.
对第八次全国热处理大会的大会报告和交流论文进行了概述和分析,并就有关我国热处理技术发展的热点问题提出了笔者的一些见解。 相似文献
60.
The attack of nickel, cobalt, iron, and alloys of these metals containing chromium and aluminum, by gases containing sulfur-oxygen,
carbon-oxygen, and nitrogen-oxygen has been studied at temperatures of 600 and 900°C. The degradation of these metals and
alloys was characterized by using standard analytical techniques with emphasis on optical metallography. Three types of accelerated
degradation were identified for the attack of alloys by gases containing another oxidant in addition to oxygen. One type of
degradation occurred because of the formation of reaction products composed of mixtures of phases involving both of the oxidants.
Another type resulted from the reaction of second oxidant phases with oxygen. The third form of degradation involved the development
of less protective phases due to thermodynamic instabilities. Thermodynamic stability diagrams are used to help account for
the effects produced by different elements in the alloys. 相似文献