电子直线加速器中计入纵向与横向耦合效应的束流包络线方程组

一、引言从束流动力学的观点出发,对于粒子束在直线加速器中的运动,有两种主要的分析方法,也即粒子轨迹跟踪法及考察束流包络运动的方法。前者是通过解单粒子运动方程,跟踪大量的单粒子运动轨迹而后进行分析;后者则是通过解束流的包络线方程,根据束流包络的变化来进     

The effect of floor slope on sub-maximal lifting capacity and technique

Inclined surfaces, where both the lifter and load are on the slope, may be encountered in a jobsite situation. The purpose of this study was to determine if facing up or down a sloped surface (10 degrees and 20 degrees ) would affect maximal acceptable weights of lift (MAWL) using a 10 min psychophysical approach with symmetric freestyle technique at 4 lifts/min. Seventeen healthy men and 18 women determined floor to knuckle height MAWL while facing uphill, downhill, and on a level surface. Motion capture was also performed to examine sagittal plane joint angles and foot placement relative to a milk crate. Slope did not alter MAWL (p>0.05) with the men lifting more than the women in every condition (p<0.001) (25 kg vs. 15 kg, respectively). Foot placement relative to the box was altered by slope such that both horizontal position behind and vertical position below the box increased as slope changed from the downhill to uphill conditions (both p<0.001). Forward torso lean as well as hip, knee, and ankle (plantar) flexion generally decreased as slope changed from the downhill to uphill conditions (all p<0.001). Torso and knee motion appeared to be protected compared to the other joints, changing the least. Though trends were the same in both sexes, interactions did exist in vertical foot position and hip angle (both p0.001). In conclusion, the body is highly adaptive to floor slope, maintaining MAWL at least in the short term. However, while slight technique differences exist between men and women, care should be taken by all when facing uphill due to the tendency to stand further from the load horizontally and when facing downhill due to increased torso lean.     

Parabolic flight as a tool to measure ocular counterrotation in a reduced force environment

Five unmedicated subjects were flown in parabolic flight. The aircraft, a Caravelle, performed single parabolae every 2 to four minutes. This resulted in alternating phases of normal, hyper-, hypo- and again hyper-gravity. Subjects sat yoga fashion upright facing towards the aircraft cockpit. Head and/or trunk were deflected 30 degrees from the upright, stimulating otolith and/or neck receptors. During each pullup, low-g phase and pullout of the parabolae a picture of the left eye was recorded on video tape. On the ground ocular roll (OCR) was determined from these video recordings. OCR ranged from 0.9 to 6.9 degrees in l-g and from 1 to 7.2 degrees under high-g, depending on head and trunk position. Neck receptor contribution was found to induce OCR of 0.2 degree to 2.1 degrees in two subjects.     

直线加速器中电荷束团的耦合包络线方程

采用直线加速器中有限圆柱空间电荷模型，利用电荷束团所产生的纵向和横向空间电荷力，推导得到了直线加速器中计入纵向与横向耦合效应的电荷束团的耦合包络线方程；通过数值计算，给出了纵向和横向几何因子变化的计算实例。     

二单元四极透镜实现x,y平面同时腰腰传输的图解设计方法

本文提出一个对于具有初始发散度的粒子束流在四极透镜对的作用下,实现x,y平面同时腰腰传输的图解设计方法。理论包括图解法和传输矩阵方法以及设计图表。文章还给出能量为100MeV,初始发散度为0.04πmc·cm的电子直线加速器的束流传输线设计的具体实例,以示上述理论之应用。     

A test bed for insect-inspired robotic control

Flying insects are remarkable examples of sophisticated sensory-motor control systems. Insects have solved the fundamental challenge facing the field of mobile robots: robust sensory-motor mapping. Control models based on insects can contribute much to the design of robotic control systems. We present our work on a preliminary robotic control system inspired by current behavioural and physiological models of the fruit fly, Drosophila melanogaster. We designed a five-degrees-of-freedom robotic system that serves as a novel simulation/mobile robot hybrid. This design has allowed us to implement a fly-inspired control system that uses visual and mechanosensory feedback. Our results suggest that a simple control scheme can yield surprisingly robust fly-like robotic behaviour.     

纵向和横向高斯型束团发射度增长的比率关系(英文)

采用直线加速器中的有限圆柱空间电荷模型,并假设该有限圆柱体电荷密度分布在纵向z和横向r都满足高斯分布,推导得到了该电荷束团的自场能与发射度增长公式;通过数值模拟计算,给出了束流发射度增长随束团参数和加速器系统参数变化的图表曲线,讨论了该纵向和横向高斯型密度分布电荷束团发射度增长的比率关系。     

束流能散度和传输管道孔径变化对束流尾场效应的影响

采用双粒子模型，讨论了束流能散度和传输管道孔径变化对由第一个宏粒子产生的束流尾场的影响。并将所得的计算尾场效应的公式，变换成六维传输矩阵的形式，使之能用于束流传输系统的模拟计算。