介绍一种新型电液伺服阀——层迭式电液伺服阀

1 概述电液伺服阀经过数十年的发展,结构不断地得到改进,性能也渐趋逐于完善。目前,电液伺服阀的频宽已可达300～500Hz,流量可达1000L/min,能满足各种使用的要求,但是,电液伺服阀在推广应用中还受到其本身一些因素的影响,限制了其使用范围。

迭层式双折射膜系双频激光器

为了简化双折射双频激光器的结构 ,减小激光谐振腔的调节难度 ,增强频差的稳定性 ,构建了一种以迭层式双折射膜系为双折射元件产生频率分裂的新型双频激光器。迭层式双折射膜系由反射膜、双折射膜和增透膜等层叠组成 ,不同的膜层独立地完成不同的功能。实验中综合利用横向塞曼效应和He Ne激光器的腔内双折射效应 ,获得了约 7.5MHz的频差。

ZnS/ZnSe迭层式波导光栅的光调制特性

报道了在ZnS/ZnSe非线性迭层式波导光栅中实现的光控反射特性和光学限制效应,在控制光强为2.60×105W/cm2的Ar+激光作用下,得到对应于二阶Bragg衍射的衍射光偏转角为-2°,相应的折射率变化为-0.049,并得到该材料的非线性折射率系数为-1.9×10-7cm2/W,同时得到其光学限制阈值约为140mW(1.42×105W/cm2),限幅阈值为24mW。

A Bilevel Programming Approach for Optimization of Airport Ground Movement

This paper proposes an optimization model for the airport ground movement problem(GMP)based on bilevel programming to address taxi conflicts on the airport ground and to improve the operating safety and efficiency.To solve GMP,an iterative heuristic algorithm is designed.Instead of separately investigating each problem,this model simultaneously coordinates and optimizes the aircraft routing and scheduling.A simulation test is conducted on Nanjing Lukou International Airport(NKG)and the results show that the bilevel programming model can clearly outperform the widely used first-come-first-service(FCFS)scheduling scheme in terms of aircraft operational time under the precondition of none conflict.The research effort demonstrates that with the reduced operating cost and the improved overall efficiency,the proposed model can assist operations of the airports that are facing increasing traffic demand and working at almost maximum capacity.

一款1.5V变6V/9V升压电路的制作

现在各种仪器、仪表常用的层迭式电池电压为6V/9V的,其市场售价较高,在一些偏远地区还难以购到。故制作这个升压电路还是有一定使用价值的。其电路工作原理较为简单,为一电流控制振荡器,在此不做叙述。元器件也无特殊要求。