BaZr(BO3)2:Eu的合成及发光性能研究

用硝酸盐热分解法成功制备了BaZr(BO₃)₂:Eu(Eu³⁺的掺杂量为摩尔分数5％)荧光材料，并研究了其在254及147nm光束激发下的发光特性.254nm光束激发下的发射主峰位于612nm处，归属于Eu³⁺的⁵D₀—⁷F₂的电偶极跃迁，但在147nm光束激发下的发射主峰位于592nm处，归属于Eu³⁺的相似文献   

高压下钨的相对电阻随压力的变化

 利用DAC装置及自己建立的实验方法，测量了过渡金属钨在高压（0.8~30.8 GPa）下相对电阻随压力的变化规律。在10 GPa以下的压力范围内，所测得的结果与Bridgman给出的结果符合较好。在10~30.8 GPa的压力范围内，钨的相对电阻随压力呈平滑下降的趋势。压力超过10 GPa的数据，还未见报道。     

Sharp polynomial estimates for the decay of correlations

We generalize a method developed by Sarig to obtain polynomial lower bounds for correlation functions for maps with a countable Markov partition. A consequence is that LS Young’s estimates on towers are always optimal. Moreover, we show that, for functions with zero average, the decay rate is better, gaining a factor 1/n. This implies a Central Limit Theorem in contexts where it was not expected, e.g.,x+Cx ^1+α with 1/2⩽α<1. The method is based on a general result on renewal sequences of operators, and gives an asymptotic estimate up to any precision of such operators.     

Photon echoes in an amplifying rare-earth-ion-doped crystal

We report what we believe is the first experimental demonstration of photon echoes in an amplifying rare-earth-ion-doped crystal. Population inversion is achieved by optical pumping, which yields high-power photon echoes, with an energy gain of as much as a factor of 5. Effects of the pump on the photon echo process highlight the advantages of an amplifying crystal. New questions concerning the optical dephasing mechanisms in Er3+:YSO have arisen.     

Wideband versatile radio-frequency spectrum analyzer

Operation of a wideband, versatile optical spectrum analyzer for radio-frequency (RF) signals is demonstrated. The device is based on spectral hole burning (SHB). The demonstration features 2.3-GHz instantaneous bandwidth, 500-kHz resolution, and a 32-dB dynamic range. A true RF signal, transferred to the optical carrier with the help of a Mach-Zehnder modulator, is analyzed with optical carrier suppression and zooming capabilities. This is to the authors' knowledge the largest instantaneous bandwidth ever demonstrated for a SHB-based processor in rare-earth-doped crystals.     

从原子分子体系出发建立热运动理论新体系

长期以来把研究热运动规律性的理论分割成热力学与统计物理两门课来讲，是不正确的。此文阐明从原子分子体系出发来研究热运动的规律，可使两者融合为一体，建立一个新的热运动理论体系。     

乘幂法的改进算法

本文提出了一种改进的乘幂法,一方面大大加快了收敛速度,另一方面可以方便地计算全部的特征值,最后给出一个计算的特征值通用算法。     

流体理论中自由电子激光器的增益

由流体理论得出了自由电子激光器的增益,并讨论了器件的小增益饱和条件。     

夸克强相互作用动力学--量子色动力学简介

夸克是人类目前所知道的最基本的粒子．所有强子（包括构成原子核的质子、中子）都是由夸克组成的．夸克的运动变化遵守什么规律呢？它们之间的强相互作用有什么特点？物理学家用量子色动力学描写夸克之间的强相互作用．本文拟对量子色动力学作个扼要介绍．