PCA和PSO-ELM在高炉铁水硅含量中的预测仿真

炉温的实时预测技术对高炉运转具有重要意义。在高炉炼铁过程中,通常以铁水硅含量来表征高炉热状态。针对硅含量预测效率和精度不足的问题,提出主成分分析和粒子群改进的极限学习机相结合的方法对高炉铁水硅含量进行预测。由于影响铁水硅含量的因素众多,且各因素之间相互影响,通过主成分分析对影响硅含量的输入变量进行降维处理。利用粒子群算法来优化极限学习机的权值和阈值,并以均方根误差作为适应度函数建立预测模型。将提取出的主成分作为模型输入,铁水硅含量作为模型输出。最后比较了极限学习机算法和粒子群改进的极限学习机,实验结果表明改进后的预测模型提高了硅含量预测的准确度,上述方法可为高炉的生产操作提供参考。     

基于无线传输的机轮胎压测试系统的设计

本文首先针对机轮胎压的测试需求进行了分析,然后简要介绍了传统机轮胎压测试技术,同时提出了一种适合的基于无线传输的机轮胎压测试技术,对其中的系统功能设计、胎压采集原理、数据收发无线通信技术、供电设计等关键技术进行了深入的探讨和研究,为机轮胎压的采集和实时监控提供了技术方法和支撑,最后通过实验室对比验证,试验结果满足飞行试验的测试需求,未来可以应用在飞行试验中满足飞机性能试飞和安全监控的需要。     

Ozonation of C.I. Reactive Yellow 3 and Further Decrease in Dissolved Organic Carbon Concentration by Post-Biodegradation

Using C.I. Reactive Yellow 3 as the target compound, the effect of the combined use of ozonation and post-biodegradation on the decrease in dissolved organic carbon (DOC) concentration was investigated, and the synergistic effect (the difference in the amounts of DOC removed by the biological process between solutions with and without ozonation) was estimated. A decrease in DOC concentration was observed during ozonation and ΔO₃/ΔDOC was decreased from 16.0 to 5.2 with increasing ozonation time. Moreover, an enhancement of biodegradability was shown. A further decrease in DOC concentration was observed during the biodegradation after ozonation. The total amount of DOC removed by the combined method was increased from 73.6 mg at 30 min to 159.9 mg at 4 h. The synergistic effect was in the range of 22.7 to 39.2 mg. BOD₅ was a better indicator of the synergistic effect than BOD₅/DOC.     

Etching of n-type silicon in (HF+oxidant) solutions: in situ characterisation of surface chemistry

The etching of n-type silicon in hydrofluoric acid solutions containing active oxidising agents has been studied. The effect of different parameters on the etch rate of silicon in these solutions has been examined. Based on electrochemical experiments coupled to in situ real-time measurements by infrared spectroscopy, the evolution of surface chemistry during etching of Si has been investigated. It has been found that dissolution of silicon may take place with and without oxide formation on the electrode surface, depending on the composition of etching solution. The transition between conditions giving rise to porous silicon generation and those leading to surface polishing was analysed, when the concentration of oxidising species is increased. In the polishing regime, oxide thickness was estimated from the intensity of the SiO absorption band.     

噻唑蓝光度法测定植物中的钼含量

采用可见分光光度法测定植物中的钼。该法在 0 .1 0～ 1 .5 μg mL钼的浓度范围内符合比耳定律 ,回收率为 95 .2 %～ 1 0 2 % ,相对标准偏差 (RSD)为 0 .5 4 %～ 3 .1 6% ,摩尔吸光系数为 5 .7× 1 0 4L·moL- 1 ·cm- 1 。该方法灵敏度高 ,选择性好     

Reformulation of oxide growth equations for oxidation of silicon bond coat in environmental barrier coating systems

The formulation of Deal and Grove for the oxidation of silicon and the growth of a silica layer is revisited to include the effects of a protective coating layer. The linear-parabolic equation of the form $x_o^2+A{x}_o=Bt$ is still applicable, but the expression for the constant A must be modified to account for the coating. The modified expression for A is a linear function of the coating thickness. The modified formulation is applied to assess recently published experimental results for the oxidation of a silicon bond coat in an environmental barrier coating. Application of the modified expression for A to the experimental results leads to an estimate of the ratio of the oxidant permeability in the oxide to its permeability in the coating.     

SiC隔板砖结合剂的选用

以硅酸乙酯作ＳｉＣ隔板砖的结合剂，可以使制品具有较好的高温性能：荷重软化温度１５８０℃、高温抗折强度（１３５０℃）２．４～２．７ＭＰａ、导热系数２．４８Ｗ／（ｍ·Ｋ）。制品在使用中无变形、断裂现象发生。     

POTENTIOSTATIC TESTING OF THIN SILICON NITRIDE FILMS

Micron-thick silicon nitride can be plasma-deposited as a conformal coating over complex geometries in microelectronic assemblies. The resulting films are dense and chemically inert, providing an effective diffusion barrier against chemical attack as long as the films remain mechanically intact. Potentiostatic methods have been developed to evaluate the effectiveness of these films over 3-dimensional microelectronic structures. Coated test structures were made the anode in NaCl solution and the resulting anodic dissolution of underlying metal was found to be a sensitive indicator of cracks or pinholes in these films and is similar to the corrosion reactions that pose reliability problems in field usage. This method was used to rank the film's ability to protect flat metalized silicon, stitch bonds, and Al bondwires from chemical attack. The same electrochemical method was used in conjunction with a four-point bending method to detect the onset of microcracking during measurements of the film's net ultimate strain.     

分光光度法测定钴—钼废催化剂中钼的研究

研究了在还原剂存在下硫氰酸钾与钼的显色反应。发现硫脲存在下，钼与硫氰酸钾在１．５～２ｍｏｌ硫酸溶液中形成橙红色络合物，其最大吸收峰位于４６０ｎｍ处，表观摩尔吸收系数１８．５×１０３Ｌ·ｍｏｌ－１·ｃｍ－１。钼浓度与钼络合物的吸光度在０～２０ｍｇ／ｍｌ范围内有良好的线性关系。     

Sintering Behaviour of Al2O3-SiC-C Ramming Mix

Silicon fines, boron acid solid powders and microfine SiO2 as sintering agents were incorporated into Al2O3-SiC-C ramming mix in order to investigated their effects on the microstructure , mechanical properties and sintering behavior of the ramming mix. Results show that all the three agents could improved both densification and mehanical properties markedly, compared to that of non-agent specimens and the effect of the composite of boron acid solid powders and microfine SiO2 is the best. The oxidation resistance increased with the addition of agents, which is supported by densification. Microstructures showed that agent powders could fill pores or produce liquid phases at high temperature, therefore, improve the sintering of the ramming mix.