激光时间传递技术的进展

激光时间传递是通过激光脉冲在空间的传播来实现地面与卫星时钟或地球上远距离两地时钟的同步。本文介绍了激光时间传递的国内外进展情况 ,重点介绍我们建立的一套地面激光时间比对系统。比对结果表明 ,激光时间传递获得很高的精度和稳定度。

时间传递技术综述

随着技术的不断发展,对时间精度的要求越来越高,而时间传递技术往往成为时间统一的瓶颈问题。针对这一现状,本文对时间传递技术进行简要介绍,阐述了单向时间传递及双向时间传递的技术特点,并介绍了几种常用时间传递技术的基本原理、应用场景、实现方式、技术指标等。

再入遥测系统GPS精密授时技术研究

从再入遥测系统时间对统一勤务信号时期基准及独立系统时时间同步的需要出发，深入论述了ＨＧＰＳ时间系统、ＧＰＳ时间传递技术、ＧＰＳ卫星时钟校正用户算法，并对ＧＰＳ时间传递精度进行了分析计算。文中提出用联测共视卫星时间传递技术消除时间系统误差，用平涔测量降低时间随机误差，探索独立系统间毫微秒时间同步技术。

Kinetic Fluorescence Spectral Analysis of Core Antennas CP43 and CP47 of Photosystem Ⅱ with Ultrafast Time-resolved Technology

Ultrafast time_resolved fluorescence experiments have been performed with core antennas CP43 and CP47 of PS Ⅱ. Their dynamic fluorescence spectra were obtained with excitation wavelength 514.5 nm. For CP43, the emission spectrum was found to be from 640 to 780 nm with a peak at ～680 nm and the lifetime of fluorescence was 3.54 ns. For CP47, the emission spectrum was from 630 to 775 nm with a peak at ～691 nm and the fluorescence lifetime was 3.22 ns. The fluorescence emission efficiencies of Chl a in CP43 and CP47 were calculated to be approximately 38.3% and 40.6%, respectively. The energy transfer from β_Car to Chl a in CP43 and CP47 was discussed. The rates of energy transfer from β_Car to Chl a were measured to be about 9.6×10 11 s -1 and 1.3×10 12 s -1 and energy transfer efficiencies 47.5% and 66.5% respectively. The edge_edge distances between β_Car and Chl a in CP43 and CP47 were estimated to be ～0.110 nm and ～0.085 nm respectively.