Luminescent properties of Ca2SiO4：Eu^3＋ red phosphor for trichromatic white light emitting diodes

The luminescent properties of Eu^3＋doped Ca2SiO4 red phosphors synthesized by the flux fusion reaction method were investigated. It was found that the excitation spectrum included two regions： the weak excitation band below 325 nm and strong narrow peaks above 325 nm. The main peak of the excitation band was located at 400 nm. The peaks located at 290 nm were assigned to the combination of the charge transfer transition of O-Eu, peaks above 325 nm （325, 385, 400, 470, 511, and 539 nm） were assigned to the f-f transitions of Eu^3＋. The emission spectrum was dominated by the red peak located at 612 nm due to the electric dipole transition of ^5D0-^7F2. In addition, the effects of the Eu^3＋ content and charge compensators of Li^＋, Na^＋, K^＋, and Cl^- ions on the emission intensity were investigated. The experiment results suggested that the strongest emission was obtained when the concentration of the Eu^3＋ ions was 0.3 mol^-1, and Li^＋ ions gave the best improvement to enhance the emission intensity. Ca2SiO4：Eu^3＋, Li^＋ was thus suitable for low-cost trichromatic white light emitting diodes （WLED） based on UV InGaN chip.     

Polarized spectral analysis of Er3+ ions in Er3+/yb3+:LiLa(MoO4)2 crystal

Optical characteristics and upconversion dynamics of Er3+ in Er3+/Yb3+:LiLa(MoO4)2 crystals were investigated. The absorption spectra, fluorescence spectra and the fluorescence decay curves were analyzed at room temperature. The infrared emission at 1538 nm and visible emissions at 520–569 and 640–670 nm, corresponding to 2H11/2,4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+ ions, were simultaneously observed in Er3+/Yb3+:LiLa(MoO4)2 crystals under 976 nm excitation at room temperature. The maximal emission cross-section near 1530 nm for π-polarization was 0.63×10–20 cm2 and the measured lifetime of 4I13/2 was 4.88 ms. The upconversion process was involved in sequential two-phonon processes, either the energy transfer from Yb3+ ions or by the excited state absorption.     

一种基于FPGA的应急动力装置控制单元超转保护系统设计

提出一种基于现场可编程逻辑门阵列（Field Programmable Gate Array,FPGA）的超转保护系统设计方案。该系统采用三余度采集、控制架构，通过软件及逻辑表决控制单元及BIT检测单元，进一步提升了超转保护系统的可靠性。相较于传统的基于CPU的转速采集系统，其具备并行处理、运算速度快、功耗低、实时性强等特点，同时能释放大量CPU资源。该设计具备较强的通用性和实用性，对应急动力装置电子控制单元的超转保护系统设计具有一定的参考借鉴意义。     

Photoluminescence of BaGdB9O（16）：Eu^3＋ co-doped Al^3＋ or Sc^3＋ under UV-VUV excitation

Single phase of BaGd0.9-xMxEu0.1B9O16 (M=Al or Sc, 0≤x≤0.3) powder was prepared by the solid-state reaction and its photoluminescence (PL) properties were investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation. Monitored with 613 nm emission, the excitation spectra of BaGd0.9-xMxEu0.1B9O16 consisted of three broad bands peaking at about 242, 208, and 142 nm, respectively. The one at about 242 nm originated from the charge transfer band (CTB) of O2-→Eu3+. The other two were assigned to the absorption of the host, which was overlapped with absorptions among borate groups, f→d transition of RE3+ (RE=Gd, Eu), and the charge transfer transition of O2-→Gd3+. The maximum emission peak was observed at about 613 nm in the emission spectra of BaGd0.9-xMxEu0.1B9O16 under both 254 and 147 nm excitation, which originated from the electric dipole 5D0→7F2 transition of Eu3+. When excited with 254 nm, the integral emission intensity of Eu3+ increased after Al3+ or Sc3+ substituting Gd3+ partly in BaGd0.9Eu0.1B9O16. Under 147 nm excitation, the integral emission intensity of Eu3+ decreased after some Gd3+ was replaced by Sc3+, but increased after adding appropriate Al3+ into BaGd0.9Eu0.1B9O16.     

一种通用集成化的离散量采集电路设计

随着飞机续航能力的提升和复杂外部环境的应用,如何实现离散量信号简单、稳定、实时的采集的同时实现小型化、通用化,是当前机载设备硬件设计方面需要考虑的问题之一。传统的离散量采集电路多为分立式器件搭建,随着采集通道的增加所用器件数量、器件功耗、印制板资源均难以得到有效优化,无法满足小型化、高集成的硬件设计。针对以上问题,提出了一种基于HKA1300型离散量输入输出接口电路芯片的采集电路,通过灵活的外围功能端口配置,可实现地/开型和28 V/开型离散量输入信号的调理采集,具有结构简单、集成度高、通用化的特点,对小型化硬件采集单元的设计具有一定的参考意义。     

无间柱连续推进分段空场崩落法在凤凰山银矿的应用

为解决留矿采矿法开采破碎、不稳固矿体所带来的矿石贫化损失问题,依据现代连续采矿思想,结合矿山生产实际情况,提出无间柱连续推进分段空场崩落采矿法.通过不留间柱连续推进、随时开采随时出矿、利用顶板围岩自然崩落处理采空区等技术,解决了使用传统方法开采此类矿体所带来的问题,矿块生产能力达到150t/a,贫化、损失指标分别从60...     

民用航空机载电子设备雷电防护设计研究

目前,一般通过DO-160G标准第22章雷电感应瞬态敏感度规定的试验方法对民用航空电子设备的雷电间接效应防护设计进行试验验证。通过梳理DO-160G标准第22章对民用航空机载电子设备的雷电间接效应防护要求,重点分析了插针注入试验和电缆束试验的具体要求,提出了民用航空电子设备雷电防护设计的要点,通过某机载电子设备雷电防护设计和验证实例进一步说明设计的实现途径。