一种矿车清车装置设计

以气体自激振动原理,设计了一种激振器,利用气源驱动激振器使矿车达到共振,从而使附着在矿车底部的黏底层自行脱落,达到清车的目的。实践证明这种清车方式在使用条件、清车速度、资金投入及对矿车的损坏程度方面都克服了一般装置的弊端,具有较高的经济效益和社会效益。     

基于PRO/E的等加等减速凸轮三维模型设计

介绍了利用Pro/E软件实现等加等减速凸轮三维模型设计的详细步骤,并利用Pro/E软件的自动编程功能,设计等加等减速凸轮的加工程序,从而有效地解决了凸轮设计及加工的精度和效率问题。     

Development of robust interfaces based on crystalline γ-Al2O3(001) for subsequent deposition of amorphous high-κ oxides

This work reports on the development of thin crystalline γ-Al₂O₃(001) interfacial layers for subsequent deposition of amorphous high-κ oxides on Si(001). High quality and single crystal of γ-Al₂O₃ have been grown by Molecular Beam Epitaxy (MBE) on silicon. This γ-Al₂O₃/Si system leads to the formation of sharp and robust interfaces. They could be used for subsequent growth of amorphous high-κ oxides like lanthanum aluminate (LaAlO₃) without forming interfacial reactions. Despite high temperatures and oxygen pressure conditions during deposition or post-annealing processes, the heterostructures are stable with respect to the silicon substrate up to 850°C.     

氧化剂对红磷烟幕抗10.6 μm激光性能的影响研究

在红磷发烟剂中分别加入四氧化三铁、三氧化二铁、氧化锰、硝酸铯、硝酸锶等氧化剂和可燃剂金属镁配制成六种发烟剂,在烟幕试验柜中测试了这六种不同配方烟幕的成烟时间、沉降速度和对10.6μm激光消光系数。研究表明,硝酸铯或硝酸锶作氧化剂时,烟幕的成烟时间分别为20 s和15 s,沉降速度分别为0.0021 m.s-1和0.0019 m.s-1,可以改善发烟剂的燃烧性能,而且烟幕对10.6μm激光的消光能力提高了41.9%和38.7%,因此,硝酸锶更适合作红磷烟幕的氧化剂。     

A probabilistic total fatigue life model incorporating material inhomogeneities,stress level and fracture mechanics

Testing on notched specimens from thin sheet aluminum 2024-T3 was carried out to investigate the formation of fatigue cracks at constituent particles and to quantify the critical distributions and their stress level dependence. The distributions of fatigue lives, nucleation lives, and crack nucleating (CN) particle sizes were determined for each specimen and exhibited a significant stress level dependence. The measured distributions provided the foundation for the total fatigue life model, which uses a probabilistic Monte Carlo method in conjunction with Newman's fastran ii crack closure model. The total life model closely predicted the cumulative distribution function (CDF) of fatigue lives for the three stress levels examined and specifically predicted the shortest fatigue lives, critical from a design for reliability standpoint, and their variability. The total life model accounted for both nucleation and propagation lives; however, the results based on modeling the total life entirely as crack propagation were accurate and slightly conservative. Additionally, a probability of crack nucleation (POCN) concept to relate the distribution of all particles to the distribution of CN particles was developed based on the experimental observations and provides a better representation of the data than traditional threshold approaches.     

二相粒子对低碳铝镇静钢织构演变规律的影响

通过单向拉伸实验检测力学性能,利用透射电镜观察化学成分不同的两种低碳铝镇静钢的析出相粒子,利用X射线衍射仪测量钢中各种织构的含量。经73%的压下率冷轧和700℃×4h退火处理,2#试样比1#试样屈服强度高28MPa,抗拉强度高19MPa,r值低0.24。结果表明:1#试样的{111}织构含量在冷轧、退火过程中都增加,Goss织构含量都减少,{100}织构含量冷轧后增加,退火后又明显减少;2#试样退火过程中析出大量Al2O3粒子抑制AlN粒子的析出,且其作为新的形核质点改变了形核机制,退火后Goss织构和{100}织构含量增加,而{111}织构含量减少,r值降低,不利于深冲性能;细小的Al2O3粒子的析出形成了细晶强化和沉淀强化,试样的屈服强度和抗拉强度都明显升高。     

粒度搭配对水雾化铁粉工艺性能的影响

为了研究粒度组成对水雾化铁粉松装密度、流动性、压缩性及压制过程的影响,将-80+100目和-325目两种粒径的水雾化纯铁粉以不同比例搭配进行研究.结果表明:通过控制不同的粒度组成,铁粉松装密度在2.84～3.42 g/cm3内变化、铁粉流动性在20～31 s/50 g内变化;与纯粗粉样品A相比,在粗粉中添加质量分数25%细粉的样品B在低压(300 MPa)下压坯密度增加,高压(≥300 MPa)时压坯密度减少;细粉质量分数为75%时的样品D与样品C相比,压坯密度均增加;全部采用-325目细粉的样品E与样品D相比,压坯密度均降低.当压制压力低于300 MPa时,压坯致密化主要由颗粒的滑移、重排决定;当压制压力高于300 MPa时,压坯致密化主要以粉末的塑性变形为主.     

适配高渗透率DG接入配电网的幅值比较式保护

对于高渗透率分布式电源(DG)接入的配电网,提出了新型综合电流幅值比较的保护原理,通过线路两端分相全电流幅值以及正序故障电流幅值的比较进行故障定位,实现了低成本与高可靠性的兼容。并通过PSCAD搭建10 kV含分布式电源配电网模型,全面仿真了不同DG渗透率、故障位置、故障类型、过渡电阻、非同步数据等多种因素对保护原理的影响。经过理论分析和仿真,证明方案能够准确实现故障定位,利用的数据简单,耐过渡电阻能力优秀,保护配置要求低,抗同步误差强。