9——18岁学生最大吸氧量的纵向研究

本文采用复盖式纵向研究法,对9—18岁男女学生的最大吸氧量进行连续4年的直接测定,分析研究了其自然发展规律及年龄、性别特征。     

数字调制类型的识别及实现

通信信号的调制识别是目前研究的热点问题.本文给出一种新的数字调制信号识别方法.高速数字专用芯片ADSP2101是此方法具体实现的重要器件,这一方法在实际通信中有着广泛的应用.     

Influence of moderate intensity physical activity levels and gender on conditioned pain modulation

This study examined the potential influence of moderate intensity physical activity (PA) levels and gender on central pain modulation using conditioned pain modulation (CPM) in healthy men and women. Twenty four individuals (12 men and 12 women) who reported engaging in the moderate intensity PA for 150 min or more per week and 24 individuals (12 men and 12 women) who reported engaging in moderate intensity PA for 60 min or less per week completed a self-report PA questionnaire and a 7-day PA assessment using an accelerometer. Furthermore, the participants completed the CPM testing to evaluate the efficiency of central pain modulation. The active individuals scored higher on the PA questionnaire and spent more minutes for light, lifestyle, moderate and vigorous intensity PA than the less active individuals. The active men and women exhibited comparable magnitudes of CPM, and showed a greater magnitude of CPM when compared to their less active counterparts. However, these beneficial effects of higher dose moderate intensity PA disappeared when time spent for vigorous intensity PA was statistically controlled for. These results suggest that the higher dose moderate intensity PA does not add to the benefits from vigorous intensity PA to further improve central pain modulatory systems.     

超快激光脉冲的产生和放大

超快激光脉冲是实现超高速通信最为重要的部分.近十年来,啁啾脉冲放大技术和宽带增益介质的结合,高功率超快激光脉冲取得了迅猛的发展.在小型实验室桌面激光器就可以产生数太瓦功率的激光.本文介绍了用啁啾脉冲放大技术实现超快脉冲的产生和放大.     

有用脉冲中干扰脉冲的去除方法

在使用计算机对外部脉冲进行计数的过程中 ,由于干扰脉冲的存在 ,计算机得到的脉冲数往往比实际的脉冲数要多 .为了得到脉冲的准确数值 ,必须想办法把干扰脉冲去掉 .本文介绍了从硬件和软件两方面去掉干扰脉冲的方法 .     

多载波系统中低复杂度的改进比特和功率分配算法

基于迭代的比特和功率分配机制,提出了一种低复杂度的比特和功率分配算法.与传统的迭代分配算法不同,该算法在每次迭代中只需要比较几个特定的子载波.该方法在保持传统迭代算法性能的前提下极大地减小了迭代分配算法的复杂度.此外,通过选择等功率分配方案作为初始方案加快了算法的收敛速度,进一步降低了算法复杂度.仿真结果表明,提出的改进算法在基本不牺牲系统性能的前提下有效地降低了算法复杂度.     

自聚焦克尔类电介质中非傍轴光束调制非稳的研究

Propagation stability of non-paraxial beam in nonlinear Kerr media is investigated with a linear stability method.Both theoretical analysis and numerical simulation show that modulation instability(MI) gain spectrum has three different distribution features determined by the times of incident power P0 and the non-paraxial parameter a. Furthermore,the corresponding criterion is put forward to distinguish the three different distributions.     

弱电统一场中赝矢量流可以转化为引力波

生物大分子DNA、RNA和氨基酸、蛋白质中普遍存在的由共价键主要是π键构成的苯环状构象,有效地将宇宙背景中低能正、反中微子汇聚,运用上述双光子引力波产生机制,将中微子能转化为光和热,揭示了正物质世界生物大分子左旋结构与反物质世界生物大分子右旋结构稳定性的起源。     

Optical QPSK/16QAM modulation based on serial-parallel MZM scheme in radio-over-fiber system

A novel scheme of optical modulation in 40 GHz radio-over fiber (RoF) system is proposed. It generates optical QPSK/16QAM signals in a serial-parallel structure of Mach-Zehnder modulators (MZMs). The millimeter-wave is obtained with optical frequency multiplication (OFM). Furthermore, modulation on optical-wave is transferred onto millimeter-wave. It can be used to increase transmission capacity of millimeter-wave RoF systems.     

嵌固在软岩中水平承载桩计算宽度的研究

水平推力桩的受力状态是非常复杂的三维空间问题。本文针对嵌固在软质岩中的水平承载桩,就计算宽度问题进行了现场试验及弹塑性有限元程序计算分析两方面的研究。本文引入扩散角的概念,用此概念说明桩侧边长度对于计算宽度的影响,从而建立计算宽度的计算公式。