Linux系统下基于PCI控制器(PLX9054)的DMA编程

DMA是实现大批量数据快速传输的一种手段。DMA的实现是高度依赖操作系统和硬件的。本文讨论了DMA编程在Linux系统下的所遇到的主要问题及解决方法。并通过实例介绍了基于PLX9054芯片的DMA实现方法。     

液面自控在合金钢连铸机上的应用

介绍了莱钢特钢厂利用铯源型液面仪实现了液面自控，并阐述了其工作原理，液面自控可使液面和拉速稳定，提高铸坯质量，减少保护渣的使用。     

The study of methanol aromatization on transition metal modified ZSM-5 catalyst

In this article, transition metals of Cu, La and Zn were used as adjuvant to prepare modified HZSM-5 by impregnation method. The catalysts were characterized by XRD, BET, NH₃-TPD and Py-IR to reveal the microstructure and acid property. The catalysis performances of methanol aromatization of catalysts were investigated in a fixed-bed reactor. The results show that the strength and distribution of acid center of these catalysts are significantly influenced by the species of transition metal. There are more mediate strong Lewis acid center in Zn modified HZSM-5 catalyst and therefore exhibits higher selectivity to aromatic, benzene, toluene and xylenes in the MTA reaction..     

Preparation and Modification of Micro-Mesoporous Carbon Materials for Toluene Adsorption

In the process of toluene adsorption, the choice of adsorbent is the key. In this work, micro-mesoporous carbon materials were prepared and characterized. The synthesis process was performed by using MCM-41 as the template, and sucrose and furfuryl alcohol as the carbon source, respectively. The toluene adsorption capacity of studied adsorbents was evaluated under different toluene initial concentration, temperature and bed height. In order to further improve the adsorption capacity, nitric acid was used for modification of the selected adsorbent. The adsorption performance after modification was also investigated. The prepared carbon materials were characteristic of typical type IV isotherms and pore size distribution was focused on micropores and mesopores. Compared with MCM-41, the prepared carbon materials showed high toluene adsorption capacity. After modification the specific surface area and oxygen groups of adsorbent were increased, making the adsorption capacity increase from 185.3 mg/g to a maximum value of 514.7 mg/g. The adsorption capacity of adsorbent mainly depended on its surface area and surface chemical property.     

一种基于贝叶斯估计的弹道导弹主动段融合算法

针对天波超视距雷达在探测跟踪弹道导弹主动段时目标航迹不连续、虚假航迹多等问题,首先将天波超视距雷达和红外预警卫星预警情报相融合,构建了天波超视距雷达与红外预警卫星融合跟踪结构模型;然后根据该模型,结合Bayes理论,提出了一种天波超视距雷达与红外预警卫星的融合算法;最后进行了仿真.仿真结果表明,对于弹道导弹主动段中的融合跟踪问题,本文提出的融合算法与求均值融合方法相比,得到的位置RMS误差平均值降低了44.2%,有效提高了弹道导弹主动段跟踪精度,表现出较强的稳定性.     

有机化学中的邻基效应

概述了邻基效就与ＳＮ２反应的区别，邻基效应要求的构象，邻基效就的特点及类型。     

碳纳米管透明导电薄膜制备技术的研究进展

介绍了碳纳米管(CNTs)的基本性质.综述了CNT-TCFs的制备工艺,评述了各种工艺的优势与局限,指出了影响CNT-TCFs性能的因素并提出了可能提高其性能的方法,评析了CNT-TCFs的应用前景以及其实现应用面临的挑战.     

重庆市中学教学楼教室照明问卷调查分析

随着生活水平的提高,人们对于学校教室照明的关心程度越来越高。针对重庆市中学教学楼教室的照明现状,结合国家最新颁布的照明规范,制定了调查问卷,通过调查问卷分析,得出了调研数据,并且最终提出了解决的初步方案:重视平均照度和照度均匀度以及色温的影响,解决黑板的眩光问题,看重照明对心理的作用,加强灯具保养维护工作,提高科研向照明实践的转换以及重视对灯具控制方式的改造。     

Interface annealing characterization of Ti/Al/Au ohmic contacts to p-type 4H-SiC

Ti/Al/Au ohmic contacts to p-type 4H-SiC in terms of a different annealing time and Ti composition are reported. At 1050℃, proper increase in annealing time plays a critical role in the Schottky to ohmic contact conversion. With the optimized annealing time, the contact with a high Ti content yields a lower specific contact resistivity(ρ_c) of 6.4×10^-5 Ω·cm² compared with the low-Ti contact. The annealed surface morphology and phase resultants were examined by scanning electron microscopy(SEM) and X-ray diffraction(XRD), respectively. For the better ohmic contact, element distribution and chemical states were qualitatively identified by X-ray photoelectron spectroscopy(XPS) depth analysis. In particular, the presence of C and a Si-related phase was discussed and associated with the change in the surface status of the as-grown epilayer of 4H-SiC during annealing. The results reveal that the out-diffused C and Si atoms, with an approximate atomic ratio of 1:1 in the contact layer, can combine to form an amorphous Si-C state. The polycrystalline graphite instead of an unreacted C cluster in the whole alloyed structure and an extra nanosize graphite flake on the outermost surface of the annealed contact were confirmed by Raman spectroscopy.     

纳米WC的制备及Pt/WC材料电催化性能研究

采用溶胶-凝胶法,以偏钨酸铵为钨源,酚醛树脂(PF)为碳源制备碳化钨(WC)。使用XRD及SEM对样品进行表征,并在酸性介质中测试工作电极的电催化性能。结果表明：制备得到的纳米WC粉体颗粒径为50-90nm,颗粒形貌近似球形。WC可与Pt协同作用加强H₂的电催化氧化作用,10wt%Pt/WC在0.5mol/L H₂SO₄ 中的电流密度达12.21mA/cm₂。