基于FPGA的QPSK信号解调技术研究

介绍了一种用数字锁相环对QPSK信号解调的方法,并将该算法在FPGA硬件中实现,给出了硬件实现FPGA的解调效果及解调的性能指标。通过解调算法和原理上的分析对QPSK信号解调全过程进行了详细说明。     

热轧平整机组自动对边系统

介绍了用于热轧带钢平整分卷机组的光电式自动对边系统的结构、工作原理和性能特点及其使用情况。该系统的应用可保证生产过程稳定,平整分卷产品质量良好。     

RESEARCH ON STABILITY OF LIQUID FILM ON HOT SOLID SURFACE IMPINGED BY SMALL DROPLETS

A heat and mass transfer model was proposed for the thin liquid film on the hot solid surface cooled by the impinging small droplets, with consideration of the effect of the droplet impact, surface tension, thermocapillary, evaporation/condensation, and van der Waals attraction. The nondimensional equation for predicting the evolution of the interface of the thin liquid film was derived in the presented model with the relevant boundary conditions. The stability of the thin liquid film impacted by cool small droplets is discussed.     

现行焦炭强度指标在太钢高炉的适用性探讨

重点论述了焦炭反应性在高炉碱金属循环富集条件下的变化,并根据国内外研究提出的反应性会发生逆转的概念,分析了太钢高炉生产的实际情况,明确了现行焦炭强度指标对太钢高炉生产的指导意义。     

Hematites Precipitated in Alkaline Precursors: Comparison of Structural and Textural Properties for Methane Oxidation

Hematite (α-Fe₂O₃) catalysts prepared using the precipitation methods was found to be highly effective, and therefore, it was studied with methane (CH₄), showing an excellent stable performance below 500 °C. This study investigates hematite nanoparticles (NPs) obtained by precipitation in water from the precursor of ferric chloride hexahydrate using precipitating agents NaOH or NH₄OH at maintained pH 11 and calcined up to 500 °C for the catalytic oxidation of low concentrations of CH₄ (5% by volume in air) at 500 °C to compare their structural state in a CH₄ reducing environment. The conversion (%) of CH₄ values decreasing with time was discussed according to the course of different transformation of goethite and hydrohematites NPs precursors to magnetite and the structural state of the calcined hydrohematites. The phase composition, the size and morphology of nanocrystallites, thermal transformation of precipitates and the specific surface area of the NPs were characterized in detail by X-ray powder diffraction, transmission electron microscopy, infrared spectroscopy, thermal TG/DTA analysis and nitrogen physisorption measurements. The results support the finding that after goethite dehydration, transformation to hydrohematite due to structurally incorporated water and vacancies is different from hydrohematite α-Fe₂O₃. The surface area SBET of Fe₂O₃_NH-70 precipitate composed of protohematite was larger by about 53 m²/g in comparison with Fe₂O₃_Na-70 precipitate composed of goethite. The oxidation of methane was positively influenced by the hydrohematites of the smaller particle size and the largest lattice volume containing structurally incorporated water and vacancies.     

Effect of Controlled Cooling After Hot Rolling on Mechanical Properties of Hot Rolled TRIP Steel

A three-step cooling pattern on the runout table（ROT）was conducted for the hot rolled TRIP steel.Microstructural evolution during thermomechanical controlled processing（TMCP）was investigated.Processing condition of controlled cooling on a ROT in the laboratory rolling mill was discussed.The results indicated that the microstructure containing polygonal ferrite,granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot rolling.TMCP led to ferrite grain refinement.Controlled cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP effect.Excellent mechanical properties were obtained through TMCP for the hot rolled TRIP steel.     

房间采暖技术与变频调速综述

本文对房间采暖技术的发展状况、技术原理、构造特点进行了归纳总结,重点分析了地板供暖的优缺点,指出了地板供暖技术在房间采暖设计中的应用前景。针对低温地板热水辐射供暖系统存在的一些工程问题,通过对水泵的控制算法的研究和探讨,提出了地板水供暖系统采用以uPD78F1213为核心的无传感器永磁同步电机矢量控制系统的方案。     

高导电性ZAO陶瓷靶材及薄膜的制备

用热等静压法烧结制备了高导电性ZAO(铝掺杂氧化锌)陶瓷靶材,并用直流磁控溅射法制备出ZAO透明导电薄膜。靶材的致密度达98.7%,电阻率为2.2?03·cm;制得薄膜的最低电阻率为9.3?04·cm,可见光平均透射率大于85%。浅析了靶材的组织结构及靶材的电学、力学性能和薄膜制备的主要实验参数对其光、电性能的影响。     

Study on Microstructure and Mechanical Properties of Hot Rolled Low Silicon Containing Phosphorus TRIP Steel

The effects of final air cooling temperature on the microstructure and mechanical properties of hot rolled 0.2C-1.9Mn-0.5Si-0.08P TRIP steel were studied by utilizing OM, SEM, TEM and tensile tests. Experimental results showed that in the multiphase microstructure of the investigated steel when the finish rolling temperature was about 820 ℃ and the final air cooling temperature was in the range of 630-700 ℃, the grain size of most of ferrite was finer (about 4 μm) and which had higher dislocation density, t...     

Effect of different thermochemical treatments on the electrochemical behaviour of a hot working steel

The X 37CrMoV5 1 KU hot working steel has been quenched and tempered, overcarburised, nitrided and nitrocarburised. The surface layers constituted after the thermochemical treatments were characterised by means of X‐ray diffraction (XRD) analyses, optical and scanning electron microscope (SEM) observations, micro‐ and macrohardness indentations. The electrochemical behaviour was evaluated in two different aggressive environments: 0.1 M Na₂SO₄ and 0.1 M NaCl solutions. While the overcarburised and the nitrocarburised samples exhibit a poor electrochemical behaviour, the presence of a nitrided surface layer enhances the corrosion resistance. This is attributable to the protective action of the nitrided layer that hinders the anodic dissolution reaction of the matrix, whereas the presence of complex carbides in the overcarburised or nitrocarburised samples causes the preferential dissolution of the ferritic matrix due to galvanic coupling phenomena. Finally, the poor corrosion resistance exhibited by the nitrocarburised sample can be ascribed to the presence of a large amount of ferrite together with little ε solid solution in the surface layer.