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51.
A new method of studying the corrosion inhibition mechanism of rare earth metal(REM) on LC4 Al alloy with the spilt cell technique was studied. The principle and experimental method of the spilt cell technique were analyzed. By measuring the change of net-electric current between the two electrodes caused by the change of the amount of oxygen in the solution and the addition of CeCl3, the influence of corrosive performance of CeCl3 on LC4 super-power aluminum alloy in the 0.1 mol·L−1 NaCl solution was investigated. Meanwhile, the conditional changes of pH values, CeCl3 solution, additire and time of performance were also studied. Finally, the features of electrode surface were revealed by using SEM and X-ray energy-dispersive spectrometry (EDS). By combining these with other electric chemical techniques, such as potential-time curve, polarization curve et al. 相似文献
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53.
Generalized difference control of parallel streams temperatures 总被引:1,自引:0,他引:1
A furnace with multiple parallel passes and multiple burners is commonly seen in petroleum refineries. In order to maintain the furnace running in a safe, stable, and high-efficiency state it is necessary to control the outlet temperatures of the multiple passes to be the same. Due to the fact that the process of the oil heating in such furnace is nonlinear, multivariable, time varying, has serious coupling among passes, has frequent dynamic changes and a large time delay, traditional control methods have trouble in controlling these temperatures, and some advanced control methods, including predictive control, adaptive control, and robust control, are usually too complex for convenient use. In this paper, a control technique, called differences control technique (DsCT), is proposed to distribute the stream flowrates such that the stream temperatures are as identical as possible. The principle of the proposed technique is explained and demonstrated, and the results of its application to a real-life petroleum refinery furnace are also reported. The DsCT technique has the following advantages: it does not need complicated design procedures, the controller structure is simple, it is easy to apply, and it can be canonically applied to furnaces with different number of passes. 相似文献
54.
This paper presents the mass transfer results from an impinging liquid jet to a rotating disk. The mass transfer coefficients were measured using the electrochemical limiting diffusion current technique (ELDCT). Rotational Reynolds number (Rer) in the range of 3.4 × 104–1.2 × 105, jet Reynolds number (Rej) 1.7 × 104–5.3 × 104 and non-dimensional jet-to-disk spacing (H/d) 2–8 were taken into consideration as parameters. It was found that the jet impingement resulted in a substantial enhancement in the mass transfer compared to the case of the rotating disk without jet. 相似文献
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青藏铁路西格二线混凝土冻融试验研究 总被引:1,自引:0,他引:1
由于工期的要求,青藏铁路西格增建二线必须进行冬期施工。根据工程状况,分析了混凝土受冻的破坏机理,针对施工环境及对混凝土设计强度和要求,进行了大量冻融试验分析,对引气剂、水胶比、砂率、粉煤灰掺量等原材料与混凝土含气量的关系及其混凝土搅拌温度与静停时间等对混凝土性能的影响进行了分析与技术论证,确保了该线冬期混凝土施工顺利进行。 相似文献
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对山西沁南地区三口煤层气井试气施工工艺进行总结分析,改进了注入压降测试管柱,采用电潜泵法对煤层排采测气。对今后煤层气井的施工具有一定的指导意义。 相似文献
60.
喷锚网支护可提高高且陡的边坡岩土结构强度和抗变形刚度,增强边坡的整体稳定性.根据公路路段的情况,路堑边坡采用喷锚网支护的形式,针对设计方案、材料要求、施工方法、技术措施,以及现场质量管理和检测问题进行探讨. 相似文献