Dynamics of 1-D Electron Motion under a Periodic Electric Field with Radiation Reaction Effect

We consider the 1-D motion of an electron under a periodic force and take into account the effect of radiation reaction dissipation force on its motion, using the formulation of novel radiation reaction force as a function of the external force expression. Two cases are considered: a simple sinusoidal time depending force, and sinusoidal electromagnetic force with position and time dependence. The purpose of the study of these cases is to bring about a way to find an experimental study to determine the validity of this novel approach for the radiation reaction force. We found that the difference of the normalized (with respect the speed of light) velocities, with and without radiation reaction, is quite small between 10-31 to 10-14 for intensities on the electric field of 10-8 to 1 Dynes/ues, which may represent some concern to measure experimentally.

Attosecond-Scale Probing of the Electron Motion in the H-Atom Groundstate

Based on recent advances in attosecond strong-field spectroscopy and the current feasibility for trapping individual groundstate H-atoms from a neon-gas matrix, an experiment to probe the groundstate motion of the electron in the H-atom is proposed here.

Motion and acceleration of electrons in high-intensity laser standing waves

The motion and the energy of electrons driven by the ponderomotive force in linearly polarized high-intensity laser standing wave fields are considered. The results show that there exists a threshold laser intensity, above which the motion of electrons incident parallel to the electric field of the laser standing waves undergoes a transition from regulation to chaos. We propose that the huge energy exchange between the electrons and the strong laser standing waves is triggered by inelastic scattering, which is related to the chaos patterns. It is shown that an electron＇s energy gain of tens of MeV can be realized for a laser intensity of 10^20 W/cm^2.

Study on electron stochastic motions in the magnetosonic wave field: Test particle simulations

Using the test particle simulation method, we investigate the stochastic motion of electrons with energy of 300 keV in a monochromatic magnetosonic(MS) wave field. This study is motivated by the violation of the quasi-linear theory assumption, when strong MS waves(amplitude up to ~1 nT) are present in the Earth's magnetosphere. First, electron motion can become stochastic when the wave amplitude exceeds a certain threshold. If an electron initially resonates with the MS wave via bounce resonance, as the bounce resonance order increases, the amplitude threshold of electron stochastic motion increases until it reaches the peak at about the 11 th order in our study, then the amplitude threshold slowly declines. Further, we find that the coexistence of bounce and Landau resonances between electrons and MS waves will significantly reduce the amplitude threshold. In some cases, the electron motion can become stochastic in the field of an MS wave with amplitudes below 1 nT. Regardless, if neither the bounce nor Landau resonance condition is satisfied initially, then the amplitude threshold of stochastic motion shows an increasing trend for lower frequencies and a decreasing trend for higher frequencies, even though the amplitude threshold is always very large(> 5 nT). Our study suggests that electron stochastic motion should also be considered when modeling electron dynamics regulated by intense MS waves in the Earth's magnetosphere.

Electronic image stabilization system based on global feature tracking

A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch, the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filteration. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational, and zooming jitter and robust to local motions.

面向人体运动检测的水凝胶基柔性应变传感器设计

在可穿戴电子设备迅猛发展的背景下,构建面向人体运动检测的可穿戴柔性应变传感器成为目前传感器研究的重点之一。基于聚丙烯酰胺(PAM)、纤维素纳米晶(CNCs)、单宁酸(TA)构建了一种导电水凝胶基柔性应变传感器。机械性能与电学性能测试结果表明,相较于其他柔性应变传感器,聚丙烯酰胺-纤维素纳米晶-单宁酸导电水凝胶基柔性应变传感器具有超长的拉伸范围(0%~2 900%)、较好的黏附性、快速的响应时间(280 ms)和良好的稳定性(超320次加载-卸载循环)。该传感器对人体关节弯曲的大应变与喉部活动的小应变等运动信号具备良好的检测功能,可用作人体运动检测的柔性可穿戴传感器。

SIMOTION D435在大口径波纹管成型机上的应用

介绍了在成型机上应用西门子Simotion D435运动控制器,通过西门子工业现场总线PROFIBUS-DP,SIMOTION D435连接人机界面及用于数字量和模拟量I/O扩展的接口模块;通过DRIVE-CLIQ总线与SIMOTION D435连接驱动单元各模块及电机编码器,采用电子凸轮功能实现对成型机的运动控制。整机自动化水平高,系统运行稳定。

Extreme Dynamics on Electronic Cam Linear Drive

One of the requirements for modem production machine is versatility and easy reconfiguration to produce new products. The production machines use fixed gearing and mechanical cams in history. The cams were used for specific stokes and cam switches were used for commissioning of technological process. This solution has disadvantages in lower production speed and no flexibility of production. This article summaries practical steps for machine modernization and highlight practical problems in modernization of older production machine. The electronic cam with direct linear drive was used for traversal motion with high peak acceleration. This paper discusses cam stoke curve design, redesign and fitting.

An Electronic Image Stabilization Algorithm Based on Efficient Block Matching on the Bitplane

This paper proposes an electronic image stabilization algorithm based on efficient block matching on the plane. This algorithm uses a hexagonal search algorithm, and uses the bit-planes to estimate and compensate for the translational motion between video sequences at the same time;As for the rotary motion vector generated in the video sequences, in order to highlight the intensity change of the image sequence, the algorithm firstly conducts Laplace transform for the reference frame, then select a number of characteristics at the image edge to make block matching with the current frame, calculate and compensate for the rotational movement that may exist finally. Through theoretical analysis and simula-tion, we prove that, as for a mixed translational and rotational motion video sequences, the proposed algorithm can reduce required time for block matching computation ,while improving the accuracy of the electronic image stabilization.

静磁场下电子束运动行为仿真

电子束具有能量集中、能量转化效率高等特点,广泛用于金属精炼、增材制造等金属加工领域。在电子束熔炼过程中引入外磁场,可调控熔体流动与凝固组织,改善材料性能,但磁场会导致电子束偏转,造成熔区偏移。针对此问题,本研究基于COMSOL仿真软件对静磁场下电子与电子束在不同外加磁场强度、发射角、扫描角及发射距离参数下的运动行为进行建模与仿真分析。结果表明:磁场下电子束与单电子的运动行为相似;在一定外加磁场下实现电子束熔炼需满足一定的临界发射角和扫描角条件,如在背景磁场为0.15 T时,发射角需小于35°,且当发射角为0°时,扫描角介于−3.5°~+3.5°之间;磁场越强,电子(束)偏转越剧烈,其临界条件范围越窄;磁场对电子(束)具有筛选、聚焦及约束作用,在满足临界发射角和扫描角条件下任意发射距离的电子(束)均能进入坩埚。本研究可为磁场辅助电子束熔炼及其他相关技术的开发提供指导。

磁场对霍尔推力器气体电离率的影响规律研究

霍尔推力器的通道磁场是推力器核心设计因素,对工质电离率和性能有重要影响作用。为深入揭示通道中线磁感应强度峰值Bmax对气体电离率的影响规律与机制,以数值模拟方法进行研究。数值模型采用单元粒子方法 (PIC)结合蒙特卡洛碰撞(MCC)方法,同时考虑电子的近壁传导作用。为验证数值模型的精度和修正模型中的经验参数,在真空罐内开展推力测量试验,以推力的测量值和计算值进行对比,修正后的模型计算误差可控制在7.5%以内。在此基础上,针对霍尔推力器通道不同的Bmax对中性气体电离率的影响规律和机理进行数值分析,发现电离率对应Bmax的变化曲线存在4个阶段:缓慢升高、急速升高、浮动不变和逐渐降低,原因为电子运动路程和激发碰撞的“短板效应”在不同Bmax下对电离碰撞产生限制程度不同。

基于电子凸轮的纸尿裤包装袋封口控制系统设计

针对传统纸尿裤封装生产线封口效率低、封口规格固定等问题,设计了一种基于电子凸轮的纸尿裤包装袋封口控制系统。将PLC FU5X-80MT、运动控制器FU5-80SSC、MR-JE系列伺服驱动器和HG-SN系列伺服电机通过SSCNETⅢ/H光纤总线相连,搭建了控制系统硬件平台。基于五次多项式插补法设计了轴位移的电子凸轮曲线,通过修改电子凸轮曲线即可达到封口规格可调的目的。实测结果表明,该电子凸轮控制系统可自动封口多种规格的纸尿裤包装袋,且封口误差小于5mm、封口合格率大于97%,完全满足企业实际封口需求,实现了纸尿裤产品的柔性封口,具有较好的应用前景。

一种基于低速风洞大迎角装置的Cam变量赋值法

在风洞试验装置的设计和运行中,多轴同步类运动机构的控制质量直接影响着模型的运动范围、气动特性的准确性。以4 m×3 m风洞大迎角尾撑机构为例,为保证该设备的控制准确度,运动轴之间的耦合关系由“一主一从”发展为“一主多从”和“多主一从”,而传统电子凸轮存在耦合关系单一的问题。针对上述问题,提出一种基于电子凸轮的Cam变量赋值法,将基于多项式计算的轨迹生成方式和动态生成关键点型电子凸轮表相结合,使系统不再局限于单一变量引导的控制模式,极大地减少了电子凸轮之间的切换次数,降低了设备的计算负荷和运行时间,适用于需要执行多轴联动的运动机构。

欧姆龙NJ在任意扩口波纹管成型机上的应用

本文介绍了在任意扩口成型机上应用欧姆龙NJ501-1400运动控制器。欧姆龙NJ501-1400运动控制器通过以太网通讯EtherNet/IP连接人机界面;通过实时工业以太网EtherCAT连接驱动单元各模块;采用电子凸轮功能实现对成型机的运动控制,完成在线扩口改变管材长度的功能。整机自动化水平高,系统运行稳定。

有磁场时电子在航天器光电子鞘层中的漂移运动

采用二级漂移近似理论，研究了在航天器光电子鞘层中与电流收集有关的电于在磁场中的运动轨道和与收集电子有关的磁瓶结构．结果表明当磁场越强，航天器表面电势越弱，磁瓶在无穷远处横截面积就越小．在光电子鞘层中，势垒对电流收集影响较大，磁瓶的横截面积在略远于势垒处有极大值．磁瓶在无穷远处的横截面积并非随着势垒距航天器距离的远近而单调变化．

基于OLCAO算法金属塑性变形磁记忆信号特征研究

塑性变形是金属材料在应力作用下产生损伤的早期阶段,对其的有效检测可预判危害的发生,实现设备破坏前的预警。针对金属磁记忆检测技术,利用量子力学密度泛函理论建立铁磁材料力磁耦合计算模型,采用原子轨道正交化线性组合法(Orthogonalized linear combination atomic orbitals,OLCAO)计算铁磁晶体在应力作用下的磁特性变化及磁记忆信号特征。结果表明:应力作用引起晶体内部电子运动状态及其分布特征改变,导致体系能带结构和电子态密度分布发生变化,材料的磁特性发生改变,定量表现为原子磁矩随应力的增加而变化。拉应力导致原子磁矩线性减小,压应力导致原子磁矩线性增大。当金属发生塑性变形时,体系的磁矩均发生突变,应力磁矩关系曲线出现拐点,变化速度变慢,表现为磁记忆信号的特殊变化特征。通过铁磁材料的拉伸及压缩试验,验证了理论计算结果的正确性。

电子振动近似理论和氢同位素在金属钛中的溶解度(三)

本文论述了电子-振动近似理论,并应用于TiH2、TiD2和TiT2基态3A2的计算,即用单个分子TiH2、TiD2和TiT2中的电子和振动能量和熵近似代表他们处于固态时的能量和熵,所得到的金属钛的氢化热力学函数ΔH0、ΔS0、ΔG0以及平衡压力与温度的关系,与文献符合很好.这表明电子振动近似理论的可应用性.计算方法为密度泛函理论B3P86/6-311G**.在此基础上进一步计算氢同位素在金属钛中的溶解度,结果合理.

采用自聚焦透镜的开关电弧运动形态光纤测试系统

研究开发了一整套新型二维光纤系统用于低压塑壳断路器开断过程电弧运动形态的测试。构成测试区域的每根光纤顶端均加装了自聚焦透镜,可有效解决观测区域重叠的问题,大大提高测量精度;电路设计采用全硬件控制逻辑,可自动完成多个通道(32路)的采样、转换及存储,与相应的缓存空间配合使用,使大量数据的同步实时高速采集过程不再受微处理器总线操作周期与容量的限制;软件系统采用发布-订阅的对象行为型设计模式实现了图形组态功能,增强了系统的适用性和灵活性。实验结果表明,在采用各种新的开断技术使低压塑壳断路器(MCCB)的 性能更高、结构尺寸更加紧凑的情况下,该系统能够有效地直接观测开断电弧的运动形态,为研究和提高塑壳断路器的开断性能提供了更为先进的精确测试手段。

铝电磁铸轧冷却区中电磁场行为探讨

介绍了铝电磁连续铸轧冷却区中电磁场的基本特性，探讨了电磁场在冷却区段的作用效果，分析了电磁场在该区中产生的几种磁势和电势，以及这几种磁势和电势的形态对铝熔体的影响，并描述了铝熔体中电子在这个区域的运动轨迹。

航空光电成像电子稳像技术

介绍了一种电子稳像技术,解决了航空平台光电成像系统视频图像帧内运动模糊和帧间不稳定问题。通过建立运动模糊的数学模型,构建二维运动模糊点扩散函数,采用维纳滤波方法,消除图像帧内运动模糊;通过灰度投影算法,检测序列图像当前帧和参考帧之间的运动矢量,采用图像补偿方法,实现序列图像稳定输出。实验结果表明,本文方法能提高信噪比,实现1 pixel的稳定精度,有效改善图像质量,输出清晰稳定的视频图像,具有精确、快速、实用的特点。