Influence of Rinse on Self-Activated Luminescence in ZnS Nanocrystallite

The self-activated (SA) luminescence in ZnS nanoparticles was studied by comparing the UV-light irradiation induced spectral change, Raman spectra, and EPR spectra of the un-rinsed and rinsed samples. The results show that the SA centers prefer to occupy the sites near the surface and that the donor of SA emission may be related to organic functional groups such as - OH, - CH3, and - CO0. The EPR signals are enhanced remarkably in the rinsed nanoparticles comparing with that in the un-rinsed ones. It is believed that organic functional groups physically combine with the surface dangling bonds of ZnS nanoparticles, leading the nonradiauve transition channels to decrease, and thus the SA emission to increase     

Preparation and Luminescent Characteristics of LaPO4∶Eu Nanoparticles and Nanowires

Nanoparticles and nanowires of LaPO4: Eu phosphors were synthesized by hydrothermal method. Their luminescent properties including electronic transition, surface effect, and temperature-dependent luminescent characteristics were systemically studied and compared to the bulk powders. It can be concluded that in comparison with the bulk powders, the fluorescence intensity decreases in nanoparticles and nanowires, while the lifetime increases, indicating that the radiative transition rate decreases. The nonradiative transition rate in nanowires decreases than that in nanoparticles due to its decreased surface to volume ratio. The temperature-dependent experiments indicate that the thermal quenching in nanopowders becomes weaker than that in the bulk powders.     

标准直流分压箱的研制与等电位屏蔽技术

介绍了研制标准直流分压箱的设计思想及其特点,阐述了等电位屏蔽技术的原理和应用于标准直流分压箱中所采用的措施。     

煤巷围岩松动圈规律研究

采用数值计算软件ANSYS，对矩形煤巷的围岩松动圈进行了数值计算，得到矩形煤巷围岩松动圈的形式，发展机理及松动圈的形状，结果表明，短形煤巷由于断面形状和围岩组成结构的关系，其松动圈的形成，发展以及最终形状均与一般巷道明显不同。     

一种生物滤波器的设计

基于鸟类羽毛吸声降噪,保护自身在飞行中免遭电磁波伤害的功能,设计了一种生物滤波器。通过Filter Solutions软件确定了这一生物滤波器各元件的参数,得到了电路频率响应图、时间响应图、S参数图和零极图。介绍了这一生物滤波器的制作工艺,并对其性能进行了分析。     

软岩巷道围岩松动圈变形机理及控制技术研究

通过对软岩巷道工程特征的研究,提出用定量指标——稳定的围岩松动圈厚度值Ｌｐ（Ｌｐ≥１５０ ｃｍ ）来判定“软岩巷道工程”的方法．以此为基础,进而分析了围岩松动圈碎胀、水胀及复合等变形机理,提出对大松动圈碎胀变形Ⅳ,Ⅴ类软岩采用锚喷网支护,Ⅵ类软岩采用联合支护,对水胀变形软岩首先采用综合防治水措施的新思路,并被大量的工程证明是正确的．     

玻璃-环氧圆柱壳的撞击吸能分析

玻璃-环氧圆柱壳(管) 的撞击试验表明它的破坏是渐进过程。根据一维应力波传播理论,提出了圆柱壳受轴向撞击破坏的简化模型, 分析了这一破坏过程中的能量变化。结果表明本文中所提出的模型能较好地描述圆柱壳受轴向撞击吸能过程。      

地下空间对城市发展的作用与二次开发

本文主要叙述了开发利用地下空间对城市发展的作用,及废弃的人防工程和矿井巷道的再利用。     

Arplas焊接技术应用及质量控制

以北京奔驰汽车有限公司某车型Arplas焊接技术应用为例,介绍Arplas焊接工艺过程及质量控制方法,分析压差的影响因素,引入本体噪声的概念。对生产中出现的缺陷进行原理分析并采取预防措施。分析及实际生产表明,在合适的参数设置及质量监控下,Arplas焊是替代激光焊的有效方式。预压压力、压差和焊接能量是Arplas焊接的重要参数,其中以压差最为关键。凸台、预压、电极头、焊枪本体噪音及电极臂导向块均对压差有影响。通过预防性维护及定期测试可以避免相关因素影响压差,获得真实的监控结果。