Garnet-based red emitting phosphors Li6MLa2Nb2O12: Eu (M=Ca,Sr, Ba): Photoluminescence improvement by changing crystal lattice

A series of novel red emitting phosphors Li₆M(La_1−xEu_x)₂Nb₂O₁₂ (M=Ca, Sr, Ba; 0≤x≤0.3) were synthesized by solid state reaction, and their structures and photoluminescence properties were investigated in detail. The excitation spectrum of Li₆M(La_1−xEu_x)₂Nb₂O₁₂ revealed two mainly excitation bands at 393 nm and 464 nm, which match well with the two popular emissions from near-UV and blue LED chips. Upon the 464 nm light excitation, Li₆MLa₂Nb₂O₁₂:Eu³⁺ phosphors exhibit a red emission centered at 608 nm, originated from the ⁵D₀–⁷F₂ transition of Eu³⁺ ions. The Eu³⁺ surrounding crystal lattice environment in the garnet-based host was changed by altering the c sites element with different radii alkaline earth Ba, Sr, and Ca. The evident photoluminescence enhancement was observed in Li₆M(La_1−xEu_x)₂Nb₂O₁₂ phosphors with the decreasing of the c sites ionic radius. The emission intensity of the optimized Li₆Ca(La_0.8Eu_0.2)₂Nb₂O₁₂ (λ_exc=464 nm) phosphor is about two times higher than that of Y₂O₃:Eu³⁺ (λ_exc=467 nm) under blue light excitation. In addition, the quenching mechanism and the relationship between the structure and photoluminescence property were also discussed.     

产品设计过程零件需求量自动计算

本文探讨了产品设计中零件需求量自动计算问题。以产品设计的CAD文件明细表为基础,形成产品的物料清单,进行设计过程零件需求量自动计算。本文首先介绍产品设计零件需求量自动计算方法,然后介绍产品设计零件需求量计算的计算机实现,最后给出了实例。     

Bioinspired and Hierarchically Textile-Structured Soft Actuators for Healthcare Wearables

Soft pneumatic actuators possess the increasing potential for various healthcare applications, such as smart wearable devices, safe human-robot interaction, and flexible manipulators. However, it is difficult to translate the existing technologies to commercial applications due to their inefficient volumetric power, sophisticated control with high operation pressure, slow production, and high cost. To overcome these issues, herein, a caterpillar-inspired actuator using hierarchical textile architectures based on simple fabrication and low-cost strategy is designed. Unlike the existing textile-based pneumatic actuators, the designed actuators are constructed by combining boucle fancy yarns with a novel trilayer-knit architecture. The as-prepared actuators concurrently possess fast response (1100° s⁻¹), large bending actuation strain (1080° m⁻¹), high-power density (272 W m⁻³), mechanical robustness, easy-programmable motions, and human-tactile comfort, which outperforms currently reported textile-based pneumatic actuators. Furthermore, due to the geometrical transition of the engineered hierarchical structure, the developed actuators exhibit superior dual-stiffness effect with stress evolution, providing a facile approach to addressing the conflict of flexibility and force output in soft fluidic actuators. This concept as a paradigm provides new insights to develop soft actuators with outstanding design flexibility, adaptability, and multifunctionality using engineered textile-structure, which has great potential for real-world applications in medical rehabilitation, physiotherapy, and soft robotics.     

虚拟油泥造型检验模板的设计与应用

借鉴检验模板在工业产品油泥建模过程中控制产品外形的作用,在虚拟油泥造型系统中引入了虚拟油泥检验模板的概念;首先,对现有汽车油泥模型模板类型进行了分析、总结;然后,根据NURBS曲面在Open Inventor中可以实现透明的特点,选择裁剪NURBS曲面的方法设计了虚拟油泥检验模板;最后,根据虚拟油泥造型在工程应用方面的需要,对检验模板的准确定位、颜色与透明度表示等问题进行了研究,并完成了某型汽车车身的虚拟油泥模型造型,验证了虚拟油泥检验模板方案的可行性。     

中国氧化锌标准

中国先后制定了纳米氧化锌国家标准、直接法氧化锌和氧化锌（间接法）国家标准、饲料级氧化锌化工行业标准、工业活性氧化锌和软磁铁氧体用氧化锌化工行业标准、医药级氧化锌中华人民共和国药典（2000年版）。现将中国已制定的国家标准和化工行业标准汇总一处，见表1。表6。     

2007年无机化工产品标准实施与修订

1实施新标准 根据国家发展和改革委员会（2006）第45号公告，批准《工业过硫酸钾》等149项行业标准，其中化工标准141项，无机盐产品标准25项，见表1。     

保护地蔬菜主要病虫害的化学防治技术

本文作者结合自身工作实践,就目前保护地蔬菜主要病虫害的防治技术现状、引发病虫害防治技术不足的成因、病虫害防治技术的改进和主要的病虫害化学防治技术进行了探讨总结,希望能为从事保护地蔬菜病虫害治理方面的各位同行提供一些有益的参考与借鉴。     

近12年来影响风电场安全运行的气象灾害因子分布特征

影响风电场安全运行的主要气象灾害因子有雷暴、台风、积冰、极端低温和沙尘暴。本文利用全国2000年-2011年近12年的逐日气象观测资料,计算分析了各影响因子的分布特征。结果表明,夏季雷暴的频发区主要集中分布在长江中下游以南地区;影响我国的登陆台风增多,登陆路径偏北。冬季北方地区的极端低温均低于-20℃,其中东北、内蒙古中东部和北疆地区低于-30℃;积冰沿长江中下游地区分布,云南东北部、贵州和湖南出现范围较大;春季沙尘暴多出现在塔里木盆地到巴丹吉林沙漠一带。最后分析了空气密度对风电机组出力的影响。     

基于VHDL的定时/计数芯片的设计

介绍了在EDA软件平台下使用VHDL开发定时／计数芯片(该芯片内部结构和操作方式以Intel8253为参考)的方法，着重讲述了模块化设计思想及状态图描述方法在硬件描述语言中的应用，并展示了其在Multisim下的仿真结果。体现了硬件描述语言在电子系统设计自动化中的方便应用。