冷轧钢表面磷化膜和硅烷膜的制备与性能

通过在冷轧钢表面进行磷化处理和硅烷化处理,应用极化曲线、硫酸铜点滴和盐水全浸泡测试其耐蚀性能,并对其与有机涂层间的结合力进行评价。结果表明,经硅烷化处理形成的硅烷膜耐蚀性能及与有机涂层间的结合力明显优于未处理的磷化膜。扫描电子显微镜(SEM)显示磷化膜的结构较为疏松,而γ-(甲基丙烯酰氧)丙基三甲氧基硅烷膜表面致密均匀。     

基于Ansys Workbench六面顶压机优化分析

通过Ansys软件建立有限元分析模型并进行静力分析,得到了金刚石压机结构在工况下的应力分布及变形情况。其次,将分析模型转换成参数化模型导入到Ansys Workbench中,通过对铰链梁结构特点和受力情况的分析,以零件体积和应力较大处的应力值为目标,选择其主要的结构尺寸(如缸底圆弧R、凸耳宽度H等)为设计变量,对R和H进行优化设计。结果表明:缸底圆弧R的大小直接影响底部应力的大小,随着R的增大,底部应力逐渐减小,但当R增大到70mm以后,应力基本不变。凸耳宽度加大,应力减小,但体积相应增大。倒角D、d对应力影响很小,但对体积影响不可忽略。     

曲柄肘杆伺服压力机驱动系统设计研究

为了实现伺服压力机低速锻冲和快速空程及回程功能,同时使其满足柔性加工要求,在详细分析伺服压力机需要解决的核心问题的基础上,提出曲柄肘杆伺服压力机驱动系统的设计方案,给出了系统曲柄肘杆机构优化设计结果和驱动电机参数,同时确定了系统控制策略。然后对驱动系统的工作特性进行了详细研究,分析校核了系统的力矩和功率特性。结果表明所设计的曲柄肘杆伺服压力机驱动系统能够对不同加工工艺进行很好地控制,满足伺服压力机的工作要求。     

冷喷涂单颗粒铜在铝基体上的显微结构研究

采用冷喷涂法在铝(Al)基体上沉积单颗粒铜(Cu),利用聚焦离子束/电子束(FIB/SEM)系统精确定位并原位制备了完整单个颗粒Cu沉积在Al基体上的透射样品,分析其显微结构及形成原因。实验结果表明,撞击过程中温度与应力分布不均匀,导致沉积Cu颗粒不均匀形变。Cu/Al界面受影响较大:颗粒动能转化为形变能和热能,打破了界面处氧化膜,使界面附近温度迅速升高,发生动态再结晶,生成金属间化合物Cu_9Al_4;Cu颗粒内距界面越远的区域,受温度和应力的影响越小,其变形主要是通过晶体内位错增殖和移动;沉积颗粒顶部,远离Cu/Al界面,几乎不受应力和温度影响,保持原始显微结构。     

平整液对冷轧带钢表面黄斑缺陷的影响

平整是冷轧带钢生产的重要工序,其可以消除带钢的屈服平台,提高其成形性能和质量。但平整液可诱发冷轧带钢表面黄斑缺陷的产生。采用扫描电镜和电化学分析手段,分析了冷轧带钢表面黄斑缺陷特征及其形成机制。结果表明:冷轧带钢表面平整黄斑缺陷的主要成分为铁氧化物,其产生过程与冷轧带钢表面电位和裂开的氧化膜电位差值有关。在平整液作用下,冷轧带钢表面氧化膜破损处可形成新的氧化膜,其生成速度越快,越有利于降低平整黄斑缺陷的发生率。平整液中添加剂磷酸盐和钼酸盐可以提高冷轧带钢表面氧化膜的生成速度,从而避免黄斑缺陷的产生。     

冷轧无取向电工钢生产问题探讨

通过现场跟踪调查、缺陷试样检测分析及缺陷卷工艺调查分析,探讨了冷轧无取向电工钢生产过程中出现的酸洗不良、冷轧窄尺及断带的原因。结果表明:酸洗不良的原因在于带钢局部热轧卷取温度过高,正常的酸洗工艺未能将氧化铁皮清洗干净;冷轧出现局部窄尺的主要原因在于酸洗预留切边量过小,当热轧来料宽度处于下限,且带钢板形不良或带钢对中不良时,酸洗圆盘剪切边量过大;断带是板形不良或对中不良所致的跑偏断带。     

Effect of process parameters on the quality of aluminium alloy Al5Si deposits in wire and arc additive manufacturing using a cold metal transfer process

A 3D print device using a cold metal transfer arc welding station to melt a metallic filler wire is developed to build aluminium part by optimising the process parameters. First tests achieved using standard pre-recorded process parameters allow to study the effect of the travel speed and the average welding power on the geometrical characteristics of mono-layer deposits and on walls built by layers superposition. Finally, a parametric study of the effect of each process parameter controlling the shape of the arc current or voltage and the filler wire feeding is carried out in order to try to improve the geometrical regularity of the deposits, and to better understand the effect of each parameter on the melting of the filler wire, its transfer on the support plate, and the geometry of the formed bead.     

Early warning system for rainfall- and snowmelt-induced slope failure in seasonally cold regions

In 2005, the Japanese government launched a new nationwide early warning system for predicting debris flow and slope failure disasters based on rainfall intensity and the Soil Water Index (SWI). However, the Japanese government has not set early warning criteria in many mountain areas. In addition, the existing early warning criteria in some areas are much higher than realistic ones, and snowmelt water is not considered in the calculation of the SWI. These two factors have been the cause of many slope failures in seasonally cold regions, induced by rainfall and/or snowmelt, which were not predicted. Therefore, this study attempts to propose a new determination method for setting early warning criteria for rainfall- and/or snowmelt-induced slope failures in seasonally cold regions. For this purpose, the study firstly proposes a combination model for estimating snow density that incorporates the hourly snowmelt water into the Japanese early warning system more accurately by using meteorological monitoring data and modeled snow density. Next, based on case studies and parametric analyses for slope stability assessment, new early warning criteria are proposed for predicting three different patterns of slope failures under two typical types of precipitation (rainfall and snowmelt) conditions. Finally, a new determination method for setting early warning criteria in seasonally cold regions is proposed by referring to the existing early warning criteria near the target area, in accordance with the precipitation types and the local ground conditions of the slopes. Since the existing early warning criteria near the target area already take the effects of the variations in local geology and geography into account, the new determination method for early warning criteria can be applied to arbitrary areas in seasonally cold regions, without directly considering the local soil properties, in the actual design and maintenance works.     

绿色技术在大型文体建筑中的应用与评价

基于绿色建筑与建筑节能行业快速发展的背景,文章以扬州高邮市文化体育休闲中心为例,阐述相关绿色建筑技术在大型文体建筑中的应用与评价。项目考虑自身的功能需求及区域特点,结合江苏省绿色建筑设计标准,因地制宜地选用了复层绿化、高效围护结构、地源热泵、太阳能热水、雨水回用、节水器具、空气质量监测、室内通风采光优化等多项绿色技术,有效节约资源、保护环境,为夏热冬冷地区大型公共建筑的绿色建筑设计提供参考。     

Effect of Cooling Press on the Optical Transmission Through Photovoltaic Encapsulants

In certain laminators for poly (ethylene-co-vinyl acetate) (EVA) encapsulation process of photovoltaic modules, cooling press (CP) is applied to the module after encapsulation. Here, the effect of CP on the optical transmission through common PV encapsulants is studied. Interestingly, CP is shown to reduce drastically the scattering of the light between 400 and 700 nm traveling through the thermoplastic polyolefin (TPO)-based encapsulant. Post-annealing tests prove this effect to be stable at the temperature up to 85°C. This work has discovered a simple solution to mitigate the milky appearance of the TPO encapsulant and hence greatly enhanced its competitiveness against EVA.