采用级联原子滤光器的新型卫星激光链路系统研究

提出级联佛克脱型原子滤光器(Linked VADOF)的新构想。从理论上分析并计算了级联佛克脱型原子滤光器的透射谱。结果表明，级联佛克脱型原子滤光器将佛克脱型原子滤光器的多峰改造为单峰结构，具有比佛克脱型原子滤光器更窄的线宽和更高的噪声抑制比。将这种新型结构应用于激光信标锁频。该锁频方案提高了信标光频率的稳定性。在此基础上，给出了发射端采用级联佛克脱型原子滤光器锁频，接收端采用法拉第型原子滤光器(FADOF)滤光的新型卫星激光链路系统。外场初步联调实验表明了该系统的可行性。     

高稳定度CPM飞秒激光特性的研究

利用最优化动力学参数的方法,获得了高稳定度的CPM飞秒激光器运转特性。激光器输出平均脉宽43fs,中心波长624nm,平均功率20mW,脉宽不稳定度±3.3％,频率不稳定度小于10~(-6)。     

一种可用于可调谐环行Ti：Al_2O_3激光器的宽带单向器

本文介绍一种宽带单向器的原理及设计。选用ＴＧＧ作磁旋光介质，旋光石英晶片作补偿片，所设计的色散补偿型宽带单向器预计可在７００～１０００ｎｍ波长范围内实现环行激光腔中的单向行波运行；将其应用在可调谐环行Ｔｉ：Ａｌ２Ｏ３激光器中，获得了良好的实验结果。     

Study on the dispersion characteristic of the plasma-loaded relativistic BWO

The dispersion characteristic of the plasma-loaded relativistic backward wave oscillator has been analyzed. The theoretical model has been established and the numerical calculations accord with the experimental results, which provides some useful suggestions on the designing of slow-wave structure of BWO.     

Improved dust capture methods for crushing plant

The use of compressive crushing equipment such as gyratory crushers within minerals processing plants can potentially generate large quantities of dust. Remedies to this problem include the retrofitting of shrouds, enclosures, local exhaust ventilation (LEV) systems and water suppression systems. The single or combined application of these systems must be optimised to ensure they operate efficiently. It is desirable that the future design planning of such facilities include integrated dust suppression and/or removal systems to ensure material delivery rates are maintained and the welfare of the workforce is protected.     

一种新型频域均衡器在水声通信中的应用

在传统频域均衡器的基础上,结合多载波频移键控调制方式的频谱结构,利用接收信号和参考信号的相关性及均衡器的滤波系数,提出了一种兼具均衡与解调功能的新型频域均衡器结构.该均衡器简单、有效地克服了水声信道中多径传播产生的码间干扰和频率选择性衰落等问题,简化了水声通信系统接收机的复杂度. 新型频域均衡器的解调原理以非相关解调算法为基础,但由于利用了均衡器的计算结果,其差错性能优于传统的非相关解调算法,计算机仿真试验表明,改进后的方法使差错性能提高了2 dB;实际水声通信实验表明,该均衡器能够有效地提高水声通信系统的可靠性,具有很好的应用前景.     

LIGHTWAVE PROPAGATION IN SUBWAVELENGTH HOLES

In this paper we evaluate methods for calculating dispersion relations for waves with wavelengths of the order of hundreds of nanometres propagating in square waveguides with imperfectly conducting walls. The methods considered here are based on those used previously for rectangular dielectric waveguides.     

A neutral gas model for electron swarms

A BGK-type Boltzmann equation for a neutral gas is considered as a model for electron swarms, because the gas and the electron Boltzmann equation have a common diffusion approximation. Both full- and half-range theory are developed using orthogonality methods of solution. Preliminary comparisons with diffusion theory are presented.     

表面包覆改性对纳米CeO2分散性的影响

了改善纳米CeO2在Zn-Al类共晶合金中的分散性,采用超声液相包覆法对纳米CeO2进行表面活性剂表面包覆改性,并用AES测定了包覆层的厚度,用TEM研究了CeO2的团聚状况,用TGA分析了有机物包覆层的炭化温度范围,最后用FE-SEM观察了CeO2在复合材料中的分散情况。结果表明,包覆在纳米CeO2表面的厚度约为20 nm的表面活性剂层提高了微粒的分散性,而且该包覆层在495℃时已经炭化。热力学计算的结果也表明,炭化层能与氧化膜反应,该反应提高了CeO2与基体间的润湿性,并使其均匀分布在基体合金中。     

碳纳米管的共价修饰

碳纳米管(carbon nanotubes, CNTs)的溶解性和分散性较差是目前制约其广泛应用及在一些有特殊要求的领域(如生物技术)应用的主要原因之一. 对CNTs进行共价修饰是改善其溶解性和分散性的有效方法之一. 目前CNTs的共价修饰主要通过两类反应来实现: 羧基的衍生反应和直接加成反应. 介绍了基于这两种反应的几种共价修饰方法, 比较了各种修饰方法的优缺点及其对CNTs的溶解性和分散性的改善效果.