Design and Synthesis of CdWO4:Sb3+ Phosphor Based on sp Energy Level Regularities of Sb3+ Ion

Sb³⁺‐activated CdWO₄ phosphors were designed according to sp energy levels regularities of Sb³⁺ ion in some inorganic compounds. The sp energy levels regularities of Sb³⁺ in dozens of compounds were established with the aid of the dielectric theory of the chemical bond for complex crystals: E_A = 6.2187?1.7584h_e, E_B = 7.019?1.957h_e, E_C = 7.259?1.964h_e. Environmental factor h_e of Cd site was calculated to be 1.6583 with the refined crystal structure and refractive index of CdWO₄:Sb³⁺. Sb³⁺‐doped CdWO₄ was synthesized through a precipitation method and its structure was refined with the General Structure Analysis System. The transition energy of A band of Sb³⁺ in CdWO₄ can be predicted to be 3.312 eV (374 nm), according to the relationship equation between E_A and environmental factor h_e. By monitoring the 521 nm emission band, the excitation spectrum gives a weak excitation band peaking at 355 nm, which was assigned to the ¹S₀–³P₁ transition of Sb³⁺ according to our prediction. Thus, Sb³⁺‐doped CdWO₄ phosphor was designed and synthesized successfully based on sp energy levels regularities of Sb³⁺ ion. This work is a great help to understand the spectroscopy of Sb³⁺ ion and will be useful for the design and development of Sb³⁺‐doped phosphors for applications.     

基于天线分集和空-时编码的抗舰载卫星天线指向损耗方法研究

本文针对舰载卫星天线指向损耗问题,将接收分集和空-时编码技术应用于舰艇卫星通信中。构建了舰船卫星通信信道模型,分析了舰载天线随机指向损耗特点,研究了接收分集和空-时编码技术,进行了舰船卫星MIMO通信性能仿真。研究结果表明,将MIMO技术应用于舰艇卫星通信可以有效改善舰载卫星天线指向损耗的不良影响。     

软件定义FiWi网络中网络编码控制方法

针对传统FiWi(光纤无线混合接入)网络中网络编码控制过程中大量Gate、Report信息交换导致的网络信息复杂、编码时延增大等问题,设计了一种支持编码功能的软件定义FiWi网络架构和基于Openflow协议的网络编码控制方法。仿真结果表明,所提出的软件定义FiWi网络架构中的集中编码控制方法及其实现方案能够减少网络中控制信息数量,提高带宽利用率,有效降低数据传输时延并提高网络吞吐量。     

FTIR光谱辐射计测量结果的非均匀性修正

由于探测器响应存在非均匀性,从而造成FTIR光谱辐射计测量结果也存在非均匀现象。通过对黑体辐射源进行测量,研究了不同视场时的方向响应分布,以及目标面积与视场面积之比对测量结果的影响。以目标理论辐射强度与仪器测量值之比作为修正系数,实现了对FTIR光谱辐射计测量结果的修正。研究结果表明:视场越大,方向响应的均匀性越差;目标与视场的面积比越小,测量值越偏离实际值;对FTIR光谱辐射计的方向响应进行均匀性修正,可提高辐射强度测试精度。     

数据中心环境要求发展动态

介绍了ASHRAE关于数据中心环境要求的变更过程,分析了数据中心温湿度对IT设备的性能和效率的影响,以及机房环境条件对节能的影响。建议数据中心设计者和建造者应根据IT业务的重要程度、IT设备形式、节能目标等多种因素综合考虑,选择合适的空调形式和环境温湿度设置点。