Characteristics of Droplets Ejected from Liquid Propellants Ablated by Laser Pulses in Laser Plasma Propulsion

The angular distribution and pressure force of droplets ejected from liquid water and glycerol ablated by nanosecond laser pulses are investigated under different viscosities in laser plasma propulsion. It is shown that with increasing viscosity, the distribution angles present a decrease tendency for two liquids, and the angular distribution of glycerol is smaller than that of water. A smaller distribution leads to a higher pressure force generation. The results indicate that ablation can be controlled by varying the viscosity of liquid propellant in laser plasma propulsion.     

飞马座火箭性能的几点分析

飞马座火箭是美国第1种机载空中发射型固体运载火箭，主要用于将小型卫星送入近地轨道，本文从空中发射，结构布局，辅助动力系统，运载能力等4个方面来说明飞马座火箭的特性。     

利用随行装药技术实现超高速发射的探讨

在探讨了运用常规方法实现超高速发射的基础上,该文着重讨论了固体随行装药(STC)技术,完成了相应的弹道摸底试验.在某30mm火炮上使质量为57g的弹丸获得了大约2115m/s的初速,在最大膛压相当的情况下,初速增加了近100m/s,初步显示了随行装药(TC)技术提高火炮初速的弹道效果,并且还有很大的增速潜力.     

日本软件企业开发管理概况

本文简要地介绍了典型的日本软件企业的开发管理模式和日本软件行业发展状况及特点,使读者对日本软件行业及其管理模式有个清楚的认识.     

Experimental evaluation of a passive fuel cell/battery hybrid power system for an unmanned ground vehicle

Unmanned vehicles are increasing the performance of monitoring and surveillance in several applications. Endurance is a key issue in these systems, in particular in electric vehicles, powered at present mainly by batteries. Hybrid power systems based on batteries and fuel cells have the potential to achieve high energy density and specific energy, increasing also the life time and safe operating conditions of the power system. The objective of this research is to analyze the performance of a passive hybrid power system, designed and developed to be integrated into an existing Unmanned Ground Vehicle (UGV). The proposed solution is based on six LiPo cells, connected in series, and a 200 W PEM fuel cell stack, directly connected in parallel to the battery without any limitation to its charge. The paper presents the characterization of the system behavior, and shows the main results in terms of performance and energy management.     

高速漏磁探伤中钢管螺旋推进参数设计与分析

介绍了钢管螺旋推进漏磁探伤原理,对钢管螺旋推进运动进行了数学建模解析及极限点分析,通过ADAMS运动仿真分析获得了对辊轮驱动钢管运动的参数影响关系,并为其作了设计说明.这为钢管高速漏磁探伤中对辊轮的设计提供了一定的理论参考依据.     

Nanorobots Constructed from Nanoclay: Using Nature to Create Self‐Propelled Autonomous Nanomachines

Self‐propelled, autonomous micro and nanomachines are at the forefront of current nanotechnology. These micro and nanodevices move actively to perform desired tasks, usually using chemical energy from their surrounding environment. Typically, these structures are fabricated via clean room or template‐based electrodeposition methodologies, which yield relatively low numbers of these devices. To utilize these machines in industrial‐scale operations, one would need an inexpensive fabrication route for mass production of nanomachines. The use of naturally occurring nanotubes, Halloysite nanoclay, to fabricate functional nanomotors in great quantities is demonstrated. These nanotubes can be mined in ton quantities and used as base for the fabrication of nanomachines. In addition, it is well known that the surface groups of Halloysite nanoclay bind strongly with heavy metals, which makes it potentially useful in environmental remediation.     

Artificial Soft Cilia with Asymmetric Beating Patterns for Biomimetic Low‐Reynolds‐Number Fluid Propulsion

In nature, liquid propulsion in low‐Reynolds‐number regimes is often achieved by arrays of beating cilia with various forms of motion asymmetry. In particular, spatial asymmetry, where the cilia follow a different trajectory in their effective and recovery strokes, is an efficient way of generating flow in low Reynolds regimes. However, this type of asymmetry is difficult to mimic and control artificially. In this paper, an artificial soft cilium that comprises two pneumatic actuators that can be controlled individually is developed. These two independent degrees of freedom allow for the first time adjustment and study of spatial asymmetry in the cilium's beating pattern. Using low‐Reynolds‐number flow measurements, it is confirmed that spatial asymmetry allows for the generation of fluid propulsion. These two‐degree‐of‐freedom soft cilia provide a platform to study ciliary fluid transport mechanisms and to mimic biologic viscous propulsion.