Co-precipitation synthesis of ZnAl2O4: Cr3+ phosphor for better light penetration in pc-LED

Cr doped ZnAl₂O₄ spinel samples were prepared by the traditional solid state reaction and co-precipitation synthetic route, and the results suggest that the co-precipitation method has some superiority in contrast to the solid state reaction method. XRD, FT-IR, and XPS spectra confirmed that the well-crystallized spinel cubic phase of ZnAl₂O₄: Cr³⁺ samples were successfully formed. The morphology of the samples was investigated by FE-SEM and FE-TEM, and the results show that the samples by the co-precipitation route can generate a smaller size of particles compared to the solid state reaction. Photoluminescence excitation spectra monitored at 686 nm are comprised of two broad excitation bands near 530 nm and 395 nm, and the emission spectra show emissions ranging from 640 to 780 nm, due to the ²E?→?⁴A₂ spin-forbidden transition of Cr³⁺ ions in spinel lattices. The optimized concentration monitored at 686 nm is 1%, while at 693 nm is 3.5%. Compared with the samples by solid state reaction method, the samples by co-precipitation method show preferable luminescent properties, such as the higher photoluminescence intensity and higher quantum efficiency. Several phosphor-converted LEDs were to investigate the applicability of the prepared samples. The results confirm that the phosphor has potential applications in plant growth and supplementing the red region in white-LEDs and the phosphors prepared by co-precipitation are more suitable to be used in phosphor-converted LED devices due to their preferable luminescent properties.

     

掺氟石英玻璃的研究

利用溶胶-凝胶法,以氟化铵(NH_4F)作掺氟源,使氟离子参与水解和聚合反应,经过热处理制成掺氟石英玻璃。在烧结时通入氟里昂(CCl_2F_2)进一步提高玻璃中氟重量含量直至2.50%。研究得出石英玻璃中氟含量与折射率、密度呈线性关系。氟有利于凝胶玻璃成块。用Raman和红外光谱研究掺氟石英玻璃结构,提出了氟进入玻璃网络的结构模型,并认为氟在玻璃中的存在状态为[SiO_3F]。     

煤岩学在炼焦配煤中的应用进展及优化配煤技术

科学合理的配煤技术对于焦化企业高质量发展至关重要,炼焦配煤技术的核心在于对原料煤煤质特性的深入认知。影响炼焦煤性质的主要因素包括变质程度、煤岩组成及第三成因因素,故煤岩学对炼焦配煤技术的研究与应用至关重要。本文论述了经验配煤、煤岩配煤及人工智能配煤3种炼焦配煤技术发展历程和现状,凝练了炼焦配煤技术的发展趋势。结合研究实际,重点梳理了煤岩学指标在炼焦配煤中的应用现状。在注重煤岩特征的同时,也需兼顾工艺指标等相关参数对炼焦煤优劣的表征。在实际应用中,各项指标参数的选择和利用需要综合考虑参数适配范围并尊重该指标与炼焦煤特性的真实对应关系。基于以上内容,提出了关联成煤时代、产地等地质因素和黏结指数、胶质层指数等工艺指标的整体思路,实现焦炭性能与原料煤特性的科学、深入关联,构建“本源-过程-结果”一体的优化配煤技术新体系。     

非均质混杂叠层梁的分层剪切理论

本文研究了正交各向异性混杂叠层梁的应力与变形计算.叠层梁是由几层弹性性质明显不同的非均质子层梁组成.对每一子层梁应用剪切理论,并假设相邻子层梁的交界面是理想连接.文中导出了关于子层梁剪切转角ψ_i的二阶常微分方程组.求解微分方程组可得到叠层梁应力与位移关于剪切转角的ψ_i解析表达式.叠层梁组分材料中任一点应力可按有效模量理论和整体——局部方法[3]求得.     

夹具特性与振动控制方式对试件响应的影响

由于夹具是振动环境试验中一个重要的参试部件，对于相同的试件，采用不同的夹具和试验控制方式，可能会对试验结果产生不同程度的影响。针对某导弹战斗部，采用ANSYS软件分析了两种不同夹具及两种控制方式对试验测点加速度响应的影响。结果表明，虽然振动控制满足要求，但夹具力学特性和试验控制方式的不同，对复杂试件上测点响应的影响是比较明显的。     

树脂表面耐磨涂层的研究

以正硅酸乙脂、KH-560、KH-570为先驱体,采用溶胶-凝胶法结合旋转涂敷法在环氧树脂基体上制备了有机硅耐磨涂层.采用铅笔硬度测试方法、漆膜的划格试验测试方法和自制耐磨性测试装置对涂层的性能进行了测试,采用扫描电镜观察薄膜的表面形貌.研究结果表明:适当的偶联剂能有效提高溶胶的稳定性和涂层的附着力;涂层硬度和耐磨性在一定温度范围内随热处理温度的提高而提高;环氧树脂经涂膜后,表面硬度和耐磨性有明显提高,表面质量得到明显改善.     

Precisely Controlled Hydration Water for Performance Improvement of Organic–Inorganic Perovskite Solar Cells

Recently, intensive studies on the role of water molecule in the formation of organic–inorganic perovskite film have been reported. However, not only the contradictive phenomena but also the complex processing technique has hindered the widespread use of water molecule in perovskite preparation. Here the hydration water is introduced into the precursors instead of water. By precisely controlling the content of hydration water, a smoother and more uniform perovskite film is obtained through a simple one‐step spin coating method. The improvement of perovskite film quality leads to highly efficient planar perovskite solar cells. Summing up the device studies and the investigation of morphology, crystallization, and optical properties, the impact of water molecule in the formation of perovskite crystal and consequences of device performance is understood. Due to its universal adaptability and simplified process, precise control of hydration water is therefore of great utility to high quality perovskite films fabrication and large‐scale production of this upcoming photovoltaic technology.     

氟对降低石英光纤包层折射率的作用

用MCVD(改进的化学气相沉积)工艺,以氟里昂(CCl_2F_2)为掺氟源制备了掺氟石英光纤包层。讨论了氟进入玻璃网络形成[SiO_3F]状态的化学反应以及氟里昂通入量与石英玻璃中氟含量的关系。     

基于Web Services的软件开发过程

解释了Web Services的相关基本概念，指出运用Web Services技术不仅可以解决软件复用中的三个原则性问题，而且还可以解决不同平台和分布类型之间的互操作和松耦合问题。SOA因其可以对持续变化的业务需求提供快速、高效地响应来复用不同类型的应用组件的能力而被广泛应用。为了实现这种灵活性，基于Web Services的软件开发应该运用文中的5种设计模式。