平均功率360 W的光谱合成纳秒脉冲光纤激光

采用多层电介质膜衍射(MLD)光栅实现多路光纤激光的共孔径光谱合成是主流的光谱合成方案。本实验搭建了4路平均输出功率为100W量级的窄线宽脉冲光纤激光器,中心波长在1058～1075nm,利用基于MLD光栅的光谱合成系统,成功获得了平均功率360W,峰值功率122 kW,脉冲能量036mJ,合成效率90,重复频率1 MHz,脉冲宽度295ns的光谱合成脉冲激光输出。最大合成功率下对应的输出光束质量因子M2小于2(M2x=193,M2y=16)。     

Multi-objective test case prioritization based on multi-population cooperative particle swarm optimization

Test case prioritization (TCP) technique is an efficient approach to improve regression testing activities. With the continuous improvement of industrial testing requirements, traditional single-objective TCP is limited greatly, and multi-objective test case prioritization (MOTCP) technique becomes one of the hot topics in the field of software testing in recent years. Considering the problems of traditional genetic algorithm (GA) and swarm intelligence algorithm in solving MOTCP problems, such as falling into local optimum quickly and weak stability of the algorithm, a MOTCP algorithm based on multi-population cooperative particle swarm optimization (MPPSO) was proposed in this paper. Empirical studies were conducted to study the influence of iteration times on the proposed MOTCP algorithm, and compare the performances of MOTCP based on single-population particle swarm optimization (PSO) and MOTCP based on non-dominated sorting genetic algorithm II (NSGA-II) with the MOTCP algorithm proposed in this paper. The results of experiments show that the test case prioritization algorithm based on MPPSO has stronger global optimization ability, is not easy to fall into local optimum, and can solve the MOTCP problem better than test case prioritization algorithm based on the single-population PSO and NSGA-II.     

几种1-3-2型压电复合材料温度弯曲形变及相关参数测试研究

利用光纤光栅传感法,对压电陶瓷/618环氧树脂、压电陶瓷/9110T有机硅树脂、压电陶瓷/9110B有机硅树脂和压电陶瓷/HASUNCAST有机硅树脂四种1-3-2型压电复合材料进行实时温度弯曲形变测试,并对其相关温度稳定性电参数进行测试分析。结果表明,压电陶瓷/9110T有机硅树脂和压电陶瓷/HASUNCAST有机硅树脂压电复合材料的介电损耗极大;压电陶瓷/9110B有机硅树脂与压电陶瓷/618环氧树脂相比,其温度弯曲形变及频率常数、相对介电常数的温度变化率小,温度稳定性更高,是提高现行压电陶瓷/618环氧树脂压电复合材料高温耐受性的良好替代材料。     

浅谈煤矿综合机械化采煤技术的发展

综合机械化采煤是指采煤工作面的破煤、装煤、运煤、支护、顶板管理等基本工序都实现机械化作业,实现矿井高产高效集中化生产是煤炭井下开采的发展方向。本文详细阐述了我国综合机械化采煤技术装备的发展现状,介绍了关键技术与装备取得的新突破。分析了我国综合机械化开采装备与国外产品存在的差距,并从提高自动化程度和关键元部件可靠性等方面提出了综合机械化采煤技术的发展趋势。     

磨削不锈钢细长轴,杆的特殊装置

一、不锈钢细长轴、杆的磨削特点不锈钢材料在磨削时韧性大,有很强的粘合力。因此,磨屑不易被切离,即使切离下来了,又常常粘附在砂轮上,填满磨粒之间的空隙,使磨粒失去切削作用,增大工件与砂轮之间的摩擦面积,降低散热能力,使磨削过程中发热现象更为严重,从而使工件表面粗糙度显著增高。同时,由于材料韧性大、强度高,砂轮磨粒容易磨钝,降低了砂轮的锋利程度,增加了径向磨削力,加剧了工件在磨削中的变形与跳动,给磨削带来很     

超级电容器瞬态响应性能测试

针对超级电容器瞬态响应性能特征搭建一套超级电容器瞬态响应测试技术平台。利用固态开关、罗氏线圈电流传感器、高速数据采集装置和计算机等组成测试平台，并对平台进行调试、校准、测试及验证其可靠性，实现对相应超级电容器的瞬态特性分析和数据研究的功能，形成超级电容器瞬态响应测试方法。