高压变频器在煤矿主扇风机节能改造中的研究与应用

介绍了高压变频调速的节能原理及在煤矿主扇风机的应用,通过对改造后较为长期的运行数据的分析表明,煤矿主扇风机经过变频改造后节能效果显著,具有明显的社会效益和经济效益。     

经阴道超声检查在75例剖宫产瘢痕处妊娠诊断中的效果分析

目的:探究经阴道超声检查在剖宫产瘢痕处妊娠诊断中的应用价值。方法:回顾性分析我院2011年3月-2013年8月门诊及住院部75例剖宫产瘢痕处妊娠患者的临床资料及超声检查资料。结果 :经阴道超声检查后发现,3例混合包块型误诊为不全流产,检出率96.00%。其中妊娠囊型72例,混合包块型3例。结论:经阴道超声检查在剖宫产瘢痕处妊娠诊断中有着极其重要的临床价值,可提高其检出率,在治疗方案的选择和治疗过程中动态观察方面有着重要的参考作用,值得临床应用及推广。     

基于模糊滑模控制的电子节气门仿真

电子节气门是一个非线性系统。本文建立了电子节气门模型,并将滑模控制和模糊控制结合起来,应用于电子节气门系统。在MATLAB平台上建立了仿真模型,仿真实验证明模糊滑模控制算法能够较好地实现对电子节气门的控制。     

Fabrication and characteristics of a 4H-SiC junction barrier Schottky diode

4H-SiC junction barrier Schottky(JBS)diodes with four kinds of design have been fabricated and characterized using two different processes in which one is fabricated by making the P-type ohmic contact of the anode independently,and the other is processed by depositing a Schottky metal multi-layer on the whole anode.The reverse performances are compared to find the influences of these factors.The results show that JBS diodes with field guard rings have a lower reverse current density and a higher breakdown voltage,and with independent P-type ohmic contact manufacturing,the reverse performance of 4H-SiC JBS diodes can be improved effectively. Furthermore,the P-type ohmic contact is studied in this work.     

5000t／d生产线窑操作优化系统

发挥现有生产线能力．最大限度地降低能源消耗及对环境的影响．走低碳经济之路是水泥企业的当务之急。要达到上述目标,必须依靠技术创新之路,其一是从硬件技改入手,提高现有生产线的工艺水平、装备水平。     

AutoCAD平台下矿区沉降预计主模块的开发与应用

由于AutoCAD缺少与采煤沉降相关的计算和分析功能,结合AutoCAD VBA与Surfer Auto-mation技术,在AutoCAD 2004平台下开发了矿区沉降预计主模块,并详细介绍了主模块中各功能模块,重点分析了主模块实现中坐标系转换、任意点下沉值计算及下沉盆地库容计算3个关键技术问题。在淮南矿区的应用实践表明,计算结果与实际情况相符,该主模块可为矿区科学开采及采后的环境综合治理提供一定的技术支持。     

麻花钻前刀面的研究

麻花钻前刀面的螺旋槽形状的不同,直接影响着主刃的切削性能和加工刀具的轴向轮廓,结合麻花钻特有的几何特性,推导了一般情况下的麻花钻端截面方程和铣刀轮廓方程,并借助LabVIEW的数学工具包编写了相应的程序,在Pro/E中进行实体验证与理论完全吻合,为麻花钻精确建模和加工刀具的轮廓设计提供了一种新的方法。     

Influence of oxygen content on the crystallinity of MgO layers in magnetic tunnel junctions

With RF sputtering process, Si/Si02/Ta/Ru/Ta/CoFeB/MgO/CoFeB/Ta/Ru structure has been grown on Si （100） substrate. Attempting different targets and adjusting the oxygen dose, the crystallization quality of the MgO layer is studied. The X-ray diffraction measurements demonstrate that crystal structure and crystallization quality of MgO layers are related to the type of target and concentration of oxygen in sputtering process. With the method sputtering Mg in an ambient flow of oxygen, not only the crystallization quality of a normal MgO layer with lattice constant of 0.421 nm is improved, but also a new MgO crystal with lattice constant of 0.812 nm is formed and the perpendicular magnetic anisotropy of CoFeB is enhanced. Also it is found that crystallization quality for both the normal MgO and new MgO is more improved with MgO target and same oxygen dose, which means that this new method is helpful to form a new structure of MgO annealed at 400 ℃ in vacuum. with lattice constant of 0.812 nm. All of the samples were     

关于中国发展涤纶的思考

通过对涤纶的市场、工艺技术、生产规模、价格、成本和投资等方面的研究,指出了我国化纤企业存在的问题,并提出了几点建议.