高效异型BaTiO_3晶体自泵浦相位共轭镜的实验研究

研究设计了一种高效异型BaTiO3晶体自泵浦相位共轭镜,获得了共轭反射率大于60％的高效输出,测出了共轭反射率随光束入射位置和晶体内光束与十C夹角的不同而变化的实验曲线,文中还给出了其它实验结果和结论．     

谐振子相干态正交相位的高阶压缩效应

本文由pegg-Barrentt的量子相位理论,研究了有限维空间谐振子相干态中的一对正交相位算符的压缩特性,讨论发现这种谐振子相干态中正交相位算符具有高阶压缩特性     

基于单片机控制的高性能数字频率合成器的设计

介绍频率合成器的结构和工作原理,并给出一种由单片机80C31控制、采用大规模数字频率合成器集成电路MC145151和波形产生电路MAX038实现的高性能数字频率合成器的设计方案。     

对零序有功功率选线方法的探讨

对自动跟踪消弧线圈接地系统进行了仿真研究.结果表明:零序功率震荡和采样误差是造成零序有功功率选线方法不准的两个主要因素.为了减小这两个因素的影响,对零序有功功率选线方法的模型进行了改进,并利用MATLAB软件对改进模型进行了验证.     

一种新的苯重氮氯化锌复盐的合成及结构

以对苯二酚为原料,通过烷基化、溴化、硝化、还原、重氮化成盐等一系列反应合成了一种新的重氮光敏剂2,5-二丁氧基（4’-甲苯基硫代）苯重氮氯化锌夏盐,并通过元素分析,紫外可见光谱,红外光谱,核磁共振等手段对产物及中间体进行表征．     

高维增广相空间中广义力学系统的Lie对称定理及其逆定理

给出高维增广相空间中广义力学系统的Ｌｉｅ对称定理及其逆定理,首先,分析运动微分方程在无限小变换下的不变性建立完整非保守广义力学系统Ｌｉｅ对称的确定方程。得到Ｌｉｅ对称的结构方程和守恒方程,其次,讨论了Ｌｉｅ对称的逆问题,最后举例说明结果的应用。     

新型数字化PWM方案的研究

章在预置相位PWM方法的基础上提出了一种新型实用的PWM控制器的数字化方法,该控制器可由简单的数字模拟电路实现,也可以由微机来控制。     

男子跳远运动员起跳腿跳深跳远练习方法研究

运用高速摄影及三维测力同步测试法,研究在不同的高台至起点远度的起跳腿啃深跳远练习中,运动员的踏跳动作结构变化及不同的着板技术对人体受力的影响。提出不同训练水平运动员合理的高台至起跳点远度及其在运用中的变化方法,认为起跳腿跳深跳远练习可作为男子跳远运动员的专门练习之一。     

Power output in traditional and ballistic bench press in elite athletes: Influence of training background

This study aimed to compare the power production in traditional bench-press (TBP) and ballistic bench-throw (BBT) exercises. Furthermore, we assessed the differences in velocity, force, and power outputs between TBP and BBT. Finally, we tested the differences between the loads used to optimize power (optimum power load; OPL) in both exercises, using three distinct power-variables: mean power (MP), mean propulsive power (MPP), and peak power (PP). Sixty athletes from different sports were divided into two groups, according to their training characteristics: hypertrophy-based trained athletes (HTA), thirty-one athletes performing hypertrophy training programmes for (at least) 12-weeks; and power-based trained athletes (PTA), twenty-nine athletes performing power-oriented training sessions for (at least) 12-weeks. Magnitude-based inferences were used to test for differences between groups. Independent of the variable analyzed (MP, MPP, or PP), the PTA produced greater power values in BBT, whereas the HTA generated higher outputs during TBP. The OPL in the HTA was likely heavier in TBP than in BBT, whereas no differences related to this variable were found in the PTA. Despite the apparent superiority of ballistics to produce power, it seems that in elite athletes, the strength-power training routine might affect the ability to apply high forces at very-high velocities.     

Velocity- and power-load relationships in the half,parallel and full back squat

This study aimed to compare the load-velocity and load-power relationships of three common variations of the squat exercise. 52 strength-trained males performed a progressive loading test up to the one-repetition maximum (1RM) in the full (F-SQ), parallel (P-SQ) and half (H-SQ) squat, conducted in random order on separate days. Bar velocity and vertical force were measured by means of a linear velocity transducer time-synchronized with a force platform. The relative load that maximized power output (Pmax) was analyzed using three outcome measures: mean concentric (MP), mean propulsive (MPP) and peak power (PP), while also including or excluding body mass in force calculations. 1RM was significantly different between exercises. Load-velocity and load-power relationships were significantly different between the F-SQ, P-SQ and H-SQ variations. Close relationships (R² = 0.92–0.96) between load (%1RM) and bar velocity were found and they were specific for each squat variation, with faster velocities the greater the squat depth. Unlike the F-SQ and P-SQ, no sticking region was observed for the H-SQ when lifting high loads. The Pmax corresponded to a broad load range and was greatly influenced by how force output is calculated (including or excluding body mass) as well as the exact outcome variable used (MP, MPP, PP).