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91.
针对夏热冬冷地区间歇式用能特点,采用ANSYS软件对外墙内外保温墙体进行热分析。通过间断式施加温度荷载模拟空调运行,分析两种保温形式的墙体内温度变化情况。研究结果表明,受墙体内侧温度荷载的影响,内保温墙体内表面温度变化明显,且热量集中分布在内侧保温层部分,不易散失;外保温墙体受内侧温度荷载的影响较小,热量在墙体内分布均匀。在相同时间内,内保温需要施加荷载的时间明显比外保温的少。 相似文献
92.
针对视频网站数据优化存储的问题,定义了文件热度的概念,利用平均值的方法描述了各个类型数据的热度。在此基础之上采用时间序列方法对数据进行预测,得到了未来十天的不同类型视频的访问情况。最后,分析了文件多个周期的热度,通过隶属度函数确定出每一个周期的淘汰阈值,通过计算不同周期的淘汰阈值,得到一个动态的淘汰阈值示意图,从而给出文件淘汰分发的原则,实现了数据的存储管理优化。 相似文献
93.
Ximena V. Yepez Haci Baykara Lei Xu Kevin M. Keener 《Journal of the American Oil Chemists' Society》2021,98(1):103-113
High-voltage atmospheric cold plasma (HVACP) treatment generates reactive gas species that induce inter- and intramolecular reactions in soybean oil. The goal of this study is to analyze the effect of HVACP treatment on the chemical structure of soybean oil in a hydrogen gas environment at atmospheric pressure. HVACP was used to treat soybean oil (15 g) for up to 6 hours by triplicate. Plasma-generated reactive gas species interact with the sample, producing three distinct fractions identified as a liquid, gel, and solid. Fatty acid profile, Fourier-transform infrared spectroscopy, proton and carbon nuclear magnetic resonance, size-exclusion chromatography, thermal properties, and peroxide value were used to characterize the chemical structure. Results indicated a lower content of polyunsaturated fatty acids, increased content of saturated fatty acids, and the presence of isomers. An insoluble portion was observed in the solid fraction and increased with treatment time up to 42% in the 6-h treated samples. Plasma species may cause two main reactions: polymerization and hydrogenation. 相似文献
94.
J. Pattison S. Celotto R. Morgan M. Bray W. ONeill. 《International Journal of Machine Tools and Manufacture》2007,47(3-4):627-634
This paper reports on the development of a novel freeform fabrication technique using a cold spray (CS) system. In the CS process, metallic powder particles are accelerated in a supersonic gas jet and impacted with a substrate at speeds in excess of 600 m/s. The non-melting nature of its deposition mechanism ensures that the sprayed material is free from thermally induced tensile stresses, while the underlying substrate remains unchanged. The process is seen as a viable method for additive manufacturing because of its high deposition rates and controllable spray jet. A process was developed to investigate the potential of non-thermal freeform fabrication and was coined Cold Gas Dynamic Manufacturing (CGDM). Here, additive and subtractive techniques were combined to enable the production of complex geometries. Whereas most CS facilities concentrate on the application of wear or corrosion-resistant coatings, CGDM is dedicated to the production of freeform components, whilst still retaining an inherent coating ability. The process can produce functional forms using novel manufacturing strategies that are unique to CS. This paper presents information on the process, and details the various strategies employed during component fabrication. It was possible to construct components from many materials, including titanium, which exhibited freeform surfaces, internal channels and embedded devices. A breakdown of the process economics is also provided, with and without helium recycling. 相似文献
95.
The corrosion inhibition of neutral red on the corrosion of cold rolled steel in 1.0 M hydrochloric acid (HCl) was studied using weight loss method and potentiodynamic polarization method. Results obtained revealed that neutral red is an effective inhibitor. It was found that the adsorption of neutral red could prevent steel from weight loss and the adsorption accorded with the Langmuir adsorption isotherm. Potentiodynamic polarization studies showed that neutral red mainly acted as a mixed-type inhibitor for steel in 1.0 M hydrochloric acid. Thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy were obtained from experimental data of the temperature studies of the inhibition process at four temperatures ranging from 30 to 45 °C. The most suitable range of inhibitor concentration was discussed. The kinetic data such as apparent activation energies and pre-exponential factors at different concentrations of the inhibitor were calculated, the effect of the apparent activation energies and pre-exponential factors on the corrosion rates of cold rolled steel was discussed. The inhibitive action was satisfactorily explained by using both thermodynamic and kinetic models. Synergism between chloride ion and neutral red was proposed. The results obtained from weight loss and potentiodynamic polarization were in good agreement. 相似文献
96.
对冷轧真空精炼轴承钢带的球化退火工艺进行了试验,并探讨了冷轧和热处理工艺对球化的影响,得出了较为理想的球化退火工艺和退火后的性能,并取得了较好的经济效益。 相似文献
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