Comparative study of the electrical properties of diamond films grown by microwave plasma assisted and hot-filament chemical vapor deposition

Schottky diodes were built on different polycrystalline diamond films grown by Microwave Plasma and Hot Filament Chemical Vapor Deposition and their electrical properties were studied. The barrier height increased with the diamond film quality and the corresponding ideality factor decreased. Even though the lower-quality HFCVD film displayed poor rectifying properties, it was found to be much less sensitive to variations in the operating conditions (air vs. vacuum). The activation energies of the films depend on morphological parameters, as preferable grain size or orientation. The bulk conduction also depends on the quality of the deposited films, changing from ohmic to trap-free or shallow trap SCLC and SCLC with an exponential distribution of traps. The hypothesis of using the electrical measurements as an indicator for film quality has been discussed.     

轧机主传动电机励磁控制分析

在技术资料短缺的情况下，结合实际经验，绘制出进口轧机主传动电机励磁控制电路图，并进行了较为详细的分析。     

焦炉装煤逸散物控制实践

分析了焦炉装煤过程烟尘产生的原因，介绍了焦炉装煤逸散物控制的新方法，以及实施后的效果。     

Finite element simulation of the mechanics of flat contact pad fretting fatigue tests

An understanding into the macro kinetic and kinematic behaviour of fretted surfaces is provided. Making use of a modified version of a previously developed in‐house two‐dimensional elastic–plastic finite element analysis numerically simulates flat contact pad fretting fatigue tests. Basic macro mechanics concepts are adopted to idealise two bodies with rough contact surfaces and loaded at two different sites with arbitrary axial loading profiles. A time scale factor is devised to recognise the earliest candidate out of the events possibly accommodated at each loading increment. The present analysis utilises a relevant experimental set up developed in the Structural Integrity Research Institute of the University of Sheffield as an application. Computational results accurate to within 1.2% and corresponding to one contact pad span and six constant normal loads acting individually with four amplitudes of two sinusoidal axial load cycles are presented. The present computations include (1) the development of the global and local normal and tangential reactions and relative sliding displacement acting along the fretting surfaces and (2) contact pad deformation, generated stress fields and plasticity development within the neighbouring region of the fretted area.     

长输管线变电所备用电源自动投入系统的改造

根据管道储运公司下属的各变电所目前的运行方式以及备用电源自动投入系统(以下简称“备自投”)的运行情况，指出了备自投使用中的不足之处，并通过增加对应断路器的辅助触点来完善备自投，使变电所运行更加可靠。     

Relation between microstructure, properties and spark plasma sintering (SPS) parameters of pure ultrafine WC powder

A combined experimental/numerical methodology is developed to fully consolidate pure ultrafine WC powder under a current-control mode. Three applied currents, 1900, 2100 and 2700 A, and a constant pressure of 20 MPa were employed as process conditions. The developed spark plasma sintering (SPS) finite-element model includes a moving-mesh technique to account for the contact resistance change due to sintering shrinkage and punch sliding. The effects of the heating rate on the microstructure and hardness were investigated in detail along the sample radius from both experimental and modeling points of view. The maximum hardness (2700 HV10) was achieved for a current of 1900 A at the core sample, while the maximum densification was achieved for 2100 and 2700 A. A direct relationship between the compact microstructure and both the sintering temperature and the heating rate was established.     

Effects of chemical and plasma surface treatments on the O2-annealed Ni/Au contact to p-Gan

The effects of boiling Aqua Regia (AQ), N₂/Cl₂ plasma followed by AQ and O₂ plasma followed by AQ surface treatments prior to Ni/Au (20 nm/20 nm) metallization to p-GaN:Mg (∼ 3 × 10¹⁷ cm^− 3) have been investigated. N₂/Cl₂ plasma was employed in a bid to lower the Ga/N and O/Ga ratios of the GaN surface to improve the contact properties to p-GaN, while O₂ plasma was employed as an alternative to incorporate O into the Ni/Au system. Results show that a low Ga/N ratio does not necessarily correspond to a better contact. The positive effect of O₂ over N₂ anneal is observed only for the AQ-treated sample, although the mechanisms responsible for its positive effect: NiO formation and Ni/Au layer-reversal were observed for all O₂-annealed contacts. We conclude that the effect of O₂ anneal on the Ni/Au contact is dependant on the p-GaN surface prior to metallization.     

非标压力机箱形主梁全约束优化设计

根据非标设备结构优化问题的特点,给出满足《钢结构设计规范》(GBJ17 88)规定的箱形主梁全约束优化设计方 法。将编制的内罚函数法优化程序应用于主梁的设计,计算结果表明,该优化方法可应用于实际设计。     

生烃化学动力学在川东北普光气田的应用

普光气田是四川盆地近期发现的规模最大、埋藏最深、资源丰度最高的气田。通过认识普光气田各个烃源岩层的贡献量、生烃关键期与构造演化的关系、油气成藏具体模式等，建立生烃化学动力学模型、标定参数，结合地区烃源岩参数和地史、热史资料，定量描述该地区的生烃过程及油裂解成气过程。认为：普光地区的主力烃源岩为下志留统泥岩；主要干酪根生油期为早二叠世末到早三叠世末期（距今286Ma至240Ma）；主要干酪根生气期为中三叠世（距今240Ma至230Ma）；主要气源是原油后期热裂解气，原油裂解成气的时间比较晚，主要油裂解成气期为早白垩世（距今144Ma至97．5Ma），从而决定了普光气田的成藏模式为“多期成藏，油气转化，晚期定位”。图2表3参33     

反复荷载下钢筋混凝土剪力墙的非线性有限元分析

本文介绍了反复荷载下非线性有限元分析程序,该程序针对钢筋混凝土剪力墙类结构的特点,采用了钢筋与混凝土复合单元计算模型,考虑混凝土裂面接触效应的反复加载混凝土应力-应变关系。在钢筋应力-应变关系中,还同时考虑了混凝土开裂后钢筋的拉伸强化效应及反复荷载下钢筋的Bausinger效应。本文还介绍了作者利用该程序对反复荷载试验的试件及Ger-venka的剪力墙板进行的计算分析。结果表明,本文所采用的分析模型是合理、准确的;和国内外以往的分析比较,本文的方法成功地消去了力-位移滞回曲线中的拐点现象,而且计算的混凝土裂缝开闭也能和实测较好地吻合。表明本文方法能为分析反复荷载下钢筋混凝土剪力墙类结构性能提供一个准确、有力的工具。