添加WC对镍基合金激光熔敷层硬度及腐蚀磨损行为的影响

探讨了添加ＷＣ的镍基合金Ｇ１１２激光熔敷层的性能，结果表明，添加２０％ＷＣ的激光熔敷层的硬度ＨＶ０．２比末添加的提高近一倍，在酸性介质中的耐蚀性有所降低，但腐蚀磨损性能却得到大改善，其腐蚀磨损机制在低冲击速度下，由犁削磨损，坑穴腐蚀及应力腐蚀变为犁削磨损为主，在高冲击速度下，两者的腐蚀磨损机制趋于一致，均为犁削磨损为主，伴以抗穴腐蚀及应力腐蚀。     

井下地磁定位的瞬间强噪声扰动规律研究

地下工程空间点位地磁扰动变化规律是地磁应急定位的基础研究之一.为了研究井下工程监测目标瞬间地磁扰动的特点与规律,选取井下6个水平巷道为试验区,开展了运输车通行和罐笼升降磁扰动时间、扰动距离和扰动噪声大小的监测和匹配定位试验.发现运输车通行和罐笼提升都会对附近点位产生瞬间磁噪声扰动,主要强噪声扰动时间一般在10 s以内,扰动数值约几百至上千纳特.这些瞬间磁扰动会直接影响地磁匹配结果精度.运用中值滤波或小波去噪的方法对匹配数据进行预处理,可以减弱匹配数据中的瞬间强噪声,提高匹配结果的精度.     

氯化法TiCl4氧化制备TiO2中气体混合研究

氯化法钛白生产中的核心技术是TiCl4气相氧化反应过程.氧化反应器是氯化法钛白生产中的核心设备,氧化反应器中射流环的开孔结构直接影响TiCl4与O2的混合效果.采用计算流体力学(CFD)的方法,研究了5种不同射流环结构对流体混合效果的影响,获得了TiCl4气体在反应管内的径向浓度分布情况,以及TiCl4与O2混合的不均匀度.结果表明,射流环开孔结构对物料的混合有显著的影响,组合开孔射流环的物料混合效果优于均匀开孔射流环,更有利于反应物流体TiCl4和O2实现快速均匀地混合.     

Machine-Learning based methods in short-term load forecasting

Short-term load forecasting is of great significance to the secure and efficient operation of power systems. However, loads can be affected by a variety of external impact factors and thus involve high levels of uncertainties. So it is a challenging task to achieve an accurate load forecast. This paper discusses three commonly-used machine-learning methods used for load forecasting, i.e., the support vector machine method, the random forest regression method, and the long short-term memory neural network method. The features and applications of these methods are analyzed and compared. By integrating the advantages of these methods, a fusion forecasting approach and a data preprocessing technique are proposed for improving the forecasting accuracy. A comparative study based on real load data is performed to verify that the proposed approach is capable of achieving a relatively higher forecasting accuracy.     

高流速含沙浑水体流变特性试验研究

加速行进中的洪水具有高含沙、高流速和粗粒径的特点,而针对洪水的流变特性研究关注点多为高含沙量,忽略了高流速即高剪切速率的特点。以黄河下游泥沙为研究对象,系统地研究了高流速剪切条件下含沙量、剪切模式、温度和盐度对流变特性的影响。结果表明,在高流速剪切条件下（剪切速率≥ 1200 s-1,对应线性流速为3.6 m/s）,含沙量在106.64 ~ 957.83 kg/m3范围内的浑水体符合牛顿流体的应力本构关系,不存在屈服应力,表观黏度与含沙量呈指数关系。温度降低并未改变浑水体的流变特性,但会使其表观黏度增加,且温度越低黏度增幅越大,浑水体黏度增大梯度约为等温度清水的数倍至十几倍。盐度变化对该测试浑水体的表观黏度和流变特性影响甚微,可忽略不计。本研究结果可为高流速水流挟沙和远距离输沙研究提供理论参考。     

Engineering practice and economic analysis of ozone oxidation wet denitrification technology

SO₂ and NO emitted from coal-fired power plants have caused serious air pollution in China. In this study, a test system for NO oxidation using O₃ is established. The basic characteristics of NO oxidation and products forms are studied. A separate test system for the combined removal of SO₂ and NO_x is also established, and the absorption characteristics of NO_x are studied. The characteristics of NO oxidation and NO_x absorption were verified in a 35 t·h^-1 industrial boiler wet combined desulfurization and denitrification project. The operating economy of ozone oxidation wet denitrification technology is analyzed. The results show that O₃ has a high rate and strong selectivity for NO oxidation. When O₃ is insufficient, the primary oxidation product is NO₂. When O₃ is present in excess, NO₂ continues to get oxidized to N₂O₅ or NO₃. The removal efficiency of NO₂ in alkaline absorption system is low (only about 15%). NO_x removal efficiency can be improved by oxidizing NO_x to N₂O₅ or NO₃ by increasing ozone ratio. When the molar ratio of O₃/NO is 1.77, the NO_x removal efficiency reaches 90.3%, while the operating cost of removing NO_x per kilogram is 6.06 USD (NO₂).     

Highly Uniform and Stable Transparent Electromagnetic Interference Shielding Film Based on Silver Nanowire–PEDOT:PSS Composite for High Power Microwave Shielding

Electromagnetic interference (EMI) shielding materials, especially ones with excellent shielding effectiveness (SE), high optical transmittance, long-term stability as well as high uniformity, are urgently desired to meet the requirements of many applications. Herein, an extremely transparent, stable and uniform silver nanowire (Ag NW)–poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composite film as an EMI shielding material is prepared, which possess excellent shielding capability to both small signal and high power microwaves (HPM). The composite film exhibits SE of 30.5 dB in the frequency range of 1–12 GHz (small signal) and simultaneously has an optical transmittance of 91.0%. The SE continuously increases to 41.4 dB, while the optical transmittance still maintains at 81.1%. The composite film is very uniform, and its SE is almost unchanged even when exposed in air for a year. The SE of this composite film under the excitation of HPM is also thoroughly investigated. The HPM SE is much larger than that of small signal. As the power density of HPM is increased, the SE firstly remains unchanged, then continuously increases, and finally saturates. The SE exceeds 50 dB with the excitation power density of 40 W. More interestingly, the SE is saturated at a fixed HPM power density.     

季辚盐对Al缓蚀作用的研究

用微分极化电阻和微分电容测量法研究3种季辚盐化合物在1mol·L-1MgCl2溶液中对Al的缓蚀作用及季辚盐分子结构对缓蚀效率的影响。结果表明,季辚盐化合物具有较好的缓蚀作用,链长的季辚盐比链短的缓蚀效率高。季辚盐在Al表面上吸附服从Langmuir吸附等温式,且为物理吸附。     

注塑制品的翘曲变形分析

主要讨论模具结构设计及塑化、脱模等阶段引起塑件翘曲变形的机理和相关因素.     

国外现代铝带冷轧机和国产先进冷轧机

介绍了国外现代化铝带冷轧机的特点和典型轧机及国内铝带冷轧机的发展。