Total Focusing Method Approach of Ultrasonic Phased Array Based on Compressed Sensing

Russian Journal of Nondestructive Testing - Nondestructive testing and evaluation technology of the total focusing method (TFM) based on full matrix capture (FMC) is a hot spot in the current array...     

低渗油田高压注水井在线酸化技术研究与试验

为实现对注水井的酸化解堵及增注降压的效果，保障低渗油田开发的高效性与安全性，对低渗油田高压注水井在线酸化技术进行研究和试验分析。制备复合酸液体系，确定在线酸化施工中的注酸速度与强度等参数，并设计在线监测装置实时监控在线酸化施工，检验结果表明，该复合酸液具有较高的螯合性与沉淀抑制性，具有较高的岩粉溶蚀率；应用该复合酸液实施在线酸化施工，施工后试验注水井的地层吸液性及注水量显著上升，井口油压及施工压力显著下降，增注降压效果明显，可解除注水井储层的堵塞物，为提升低渗油田开发的安全性与高效性提供保障。实验结果表明，所提技术使井口的油压由9.11MPa降到1.71MPa、泵注压力由9.77MPa降到7.51MPa，说明能有效缓解井口油压以及泵注压力，加大整体的施工排量，实现增注降压的目标。     

CO2 sensing properties and mechanism of PrFeO3 and NdFeO3 thick film sensor

The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO_3 sensors increase with an increase in room-temperature relative humidity. When exposed to1000 ppm CO_2, the response of PrFeO_3 thick film based on nano-powders annealed at 700℃can reach8.44 at 160℃for the background of wet air with 58%of room-temperature relative humidity (RH),which is much larger than the corresponding value (3.03) in wet air with 25%RH. The sensing response S of NdFeO_3 thick-film sensor based on nano-powders annealed at 600℃to 3000 ppm CO_2 at the operating temperature 200℃can reach 2.36 for the background of wet air with 72%RH, which is larger than the corresponding value (1.83) in the air with 25%RH. Compared with other CO_2 sensing materials, the PrFeO_3 sensor has larger response at lower operating temperature for CO_2 gas and may be used as a new CO_2 sensing material.     

Effects of Undercooling and Transformation Time on Microstructure and Strength of Fe–C–Mn–Si Superbainitic Steel

Strength of Materials - A metallographic method, dilatometry, and X-ray diffraction were applied to investigate the effects of undercooling and holding time on bainitic transformation,...     

配加蒙古精矿对球团矿性能的影响

对蒙古精矿在包钢624 m2带式球团的合理利用进行了全面研究。研究表明，随着蒙古精矿配比增加，球团矿品位提高，还原膨胀率增加，当配比小于20%时，还原膨胀率小于20.0%，主要是由于还原后球团矿矿物组成中析出大量金属铁，在浮氏体(FexO)转变为铁的阶段，铁晶粒自浮士体表面向外长出晶须，晶须的生长让晶粒产生位移或晶粒开裂，导致球团结构疏松发生膨胀。通过添加适量矽石，可显著降低球团还原膨胀率，当配加30%～50%的蒙古精矿时，可通过添加1.0%～2.0%的矽石，将球团还原膨胀率降低至20%以内，球团矿质量满足高炉冶炼生产要求。     

An improved method for the hot strip mill production scheduling problem

In most research on the hot strip mill production scheduling problem (HSMPSP) arising in the steel industry, it is accepted that a schedule with lower penalty caused by jumps of width, hardness, and gauge will result in lower roller wear, so it is regarded as a better schedule. However, based on the analysis of production processes, it is realised that rolling each coil also cause roller wear. In order to assessing the roller wear associated with production scheduling more precisely, it is necessary to consider it as another factor besides those jumps, especially when complicated constraints are involved. In this paper, an improved method is proposed to quantify the expected wear of the rollers done by those jumps and rolling processes. Then the HSMPSP whose objective is to maximise the total length of all scheduled coils is formulated as a team orienteering problem with time windows and additional production constraints. A heuristic method combining an improved Ant Colony Extended algorithm with local search procedures dedicated to HSMPSP is developed. Finally, computational results on instances generated based on production data from an integrated steel mill in China indicate that the proposed algorithm is a promising solution specific to HSMPSP.