Reducing Pb concentration in α-CsPbI3 based perovskite solar cell materials via alkaline-earth metal doping: A DFT computational study

Full inorganic perovskite solar cell materials have shown significantly improved performance in recent years. To reduce their reliance on Pb, alkaline-earth metal ions (Ba, Sr, Ca, and Mg) have been employed for the exchange of Pb in α-CsPbI₃. In this study, density functional theory calculations were used to study the structures, band structures, and optical absorption properties of these alkaline-earth-metal doped α-CsPbI₃ materials with CASTEP (2017) and Dmol³ (2017). The calculation also investigated the effect of spin-orbit coupling. Alkaline-earth metal doping can enlarge the band gap of α-CsPbI₃ and convert α-CsPbI₃ from a direct gap semiconductor to an indirect gap semiconductor. After alkaline-earth metal doping, the sun-light absorption increased. Among all the alkaline-earth metals studied here, Mg-doped α-CsPbI₃ showed the most improved indirect gap band structure, ideal band gap (compared to α-CsPbI₃), and sun-light absorption.     

消失模铸造在大型床身铸件中的应用

介绍了采用消失模铸造工艺生产机床床身铸件的经验,包括模样的制作、涂料的选用、造型及浇注工艺的制定等。     

42CrMo材料硬齿面齿轮全寿命试验及数据分析

针对高炉无料钟炉顶传动中心轮——42CrMo硬齿面齿轮常发生齿根的弯曲疲劳折断,设计完成42CrMo硬齿面齿轮大样本全寿命成组试验。通过对试验齿轮疲劳寿命数据处理,得到可靠度0．99时齿轮定寿命下的极限应力分布和不同可靠度下的S—N曲线,为此类硬齿面传动的小子样试验预测和虚拟全寿命疲劳设计提供依据。     

全淀粉生物降解塑料技术研究现状

阐述了淀粉基生物降解塑料的研究现状及发展趋势;重点介绍了全淀粉生物降解塑料技术,从天然淀粉材料本身的多种理化特性着手,对全淀粉塑料的研究背景、现状、特点进行了较为全面的论述;并在此基础上总结归纳出了其今后的发展趋势。     

Numerical simulation of full penetration laser welding of thick steel plate with high power high brightness laser

Full penetration laser welding was carried out on a 10 mm steel plate using a 16 kW maximum power continuous wave thin disk laser. Upper surface and lower surface of molten pool were observed synchronously with two high speed CCD cameras during the welding process. The lower surface was much longer and more unstable than the upper one. A three dimensional laser deep penetration welding model in which volume of fluid (VOF) method was combined with a ray-tracing algorithm was used to simulate the dynamic coupling between keyhole and molten pool in laser full penetration welding. The calculated weld cross-section morphology and molten pool length on both upper side and lower side agree well with experimental results. Evolution of molten pool in lower side during full penetration laser welding was analyzed, periodical features of energy coupling, molten pool behavior and keyhole dynamics in laser full penetration welding were identified and discussed.     

载质量220 t电动轮自卸车全液压转向系统设计

电动轮自卸车是露天矿山物料运输的重要工程车辆。矿区复杂的道路状况对电动轮自卸车的转向系统提出了较高的要求。针对载质量220t电动轮自卸车的全液压转向系统,从分析自卸车转向负载出发,计算了全液压转向系统的主要性能参数,并以此为基础,确定了转向液压缸、转向器、流量放大器、转向液压泵和转向蓄能器的主要性能参数。并给出了全液压转向系统的总设计图及元件布置图。     

干砂对EPS模样垂直向下盲孔充填性的研究

研究了干砂对ＥＰＳ模样中垂直向下盲孔的充填性能,主要工艺因素,如管径、管口深度、干砂粒形、振动方向、振动维数、振动频率、振动加速度等对垂直向下盲孔充填高度的影响。初步探讨了干砂对垂直向下盲孔充填的机理。     

柴油机气缸盖消失模铸造模具CAD/CAM

详细地介绍了消失模铸造模具CAD/CAM的设计思路和制造工艺流程 ;采用该技术 ,有效地改善了模具的结构 ,明显地缩短产品模具的开发周期 ,成功地完成了柴油机气缸盖消失模模型的生产制作任务 ;实现了消失模铸造模具的国产化。     

基于全矢谱 ARMA模型的机械振动强度预测研究

单通道预测方法由于获取振动信息不完善的缺陷,导致预测结果一致性差,从而不能实现故障的预测。针对单通道信息不完善的缺陷,将时序预测重要方法 ARMA模型结合基于同源信息融合技术的全矢谱技术,提出了全矢谱-ARMA模型预测方法。全矢谱是由互相垂直的两个通道获取的信息融合而成,在同一截面其频谱结构不会随着一对传感器安装的方位不同而变化。通过全矢谱获得的频谱结构具有唯一性,因此该方法能够实现预测并且结果一致性好,从而能够实现对故障的预测。实验表明:该方法预测结果好,并且比较实用。     

基于LabVIEW的全液压制动测试系统的设计

为了实现对全液压制动系统的压力、流量、温度等参数的自动检测,基于模块化和虚拟化的思想,以Lab VIEW为软件平台,以NI的数据采集卡等为硬件基础,实现对全液压制动系统的数据采集和数据存储。用虚拟仪器代替了实际物理仪器,降低了测试系统的成本,缩短了测试试验的时间。