Frequency dependence of plasma characteristics at different pressures in cylindrical inductively coupled plasma source

The effects of driving frequency on plasma parameters and electron heating efficiency are studied in cylindrical inductively coupled plasma (ICP) source. Measurements are made in an Ar discharge for driving frequency at 13.56/2 MHz, and pressures of 0.4–1.2 Pa. In 13.56 MHz discharge, higher electron density (n_e) and higher electron temperature (T_e) are observed in comparison with 2 MHz discharge at 0.6–1.2 Pa. However, slightly highern_e andT_e are observed in 2 MHz discharge at 0.4 Pa. This observation is explained by enhanced electron heating efficiency due to the resonance between the oscillation of 2 MHz electromagnetic field and electron-neutral collision process at 0.4 Pa. It is also found that the variation ofT_e distribution is different in 13.56 and 2 MHz discharge. For ICP at 13.56 MHz, T_e shows an edge-high profile at 0.4–1.2 Pa. For 2 MHz discharge,T_e remains an edge-high distribution at 0.4–0.8 Pa. However, the distribution pattern involves into a center-high profile at 0.9–1.2 Pa. The spatial profiles ofn_e remain a center-high shape in both 13.56 and 2 MHz discharges, which indicates the nonlocal kinetics at low pressures. Better uniformity could be achieved by using 2 MHz discharge. The effects of gas pressure on plasma parameters are also examined. An increase in gas pressure necessitates the rise ofn_e in both 13.56 and 2 MHz discharges. Meanwhile, T_e drops when gas pressure increases and shows a flatter distribution at higher pressure.     

基于无谐波检测和选择性谐波补偿原理的组合式同相供电系统控制策略

针对组合式同相供电系统同相补偿装置(CCD)的常规控制方法受负载电流检测精度影响严重,且不能良好跟踪高速铁路负载高次谐波电流的缺陷,提出一种选择性谐波电流控制策略。该控制策略仅需要保留CCD的两单相变流器输出电压、电流的检测部分,不需要检测负载电流;并通过矢量比例积分控制器对连接负载的单相变流器输出电流误差中的各次谐波单独跟踪。该设计方法不受负载电流检测精度的影响,对牵引负荷各个频段谐波都具有良好的跟踪性能。利用MATLAB/Simulink搭建组合式同相供电的常规控制模型、改进控制模型和基于改进控制策略的半桥四臂模块化多电平电路模型,对交-直型、交-直-交型、混跑3种负载分别进行控制,仿真验证了改进电流控制方法的正确性以及在实际工程实现中的有效性。     

家庭智能产品的主动交互设计研究

目的 分析AI介入产品带给人机交互方式的转变,从被动交互到强迫式主动交互以及主动交互,对比智能产品交互形式及其差异,剖析智能产品主动性的研究,提出家庭智能产品主动交互形式及设计注意要点,以及智能体DNA双螺旋四联体主动交互设计模型。在人口老龄化社会背景下,结合智能产品潜在的大量用户,即老年群体为例,提升智能产品的使用效率。方法 对智能产品交互形式进行文献研究与对比研究,采用问卷分析法、用户访谈法及非参与式观察法等,结合实际案例进行分析。结论 智能产品交互系统分为被动交互、强迫式主动交互和主动交互,且在人机交互起点、主动权、数据驱动与AI决策等方面存在差异,家庭智能产品功能与内容的主动性服务,能够提高人机沟通的连贯性,有效帮助老年用户提升使用效率与体验。     

基于CMR+FBS方法模型的家庭智能体交互设计

目的 FBS（即功能—行为—结构）认知计算设计模型对内容容器的设计缺乏对应的有效指导方法。本文提出针对内容功能关系需求的CMR认知计算设计模型,探讨家庭智能体交互设计的功能与内容设计的本体论框架。方法 除了在家庭智能体的功能设计中引入FBS模型,本文还提出了针对智能体及人机交互内容设计的CMR（即内容—心智及交互模型—需求与关系）设计模型。其中,内容包括用户自身产生内容（UGC）、专业生产内容（PGC）、职业生产内容（OGC）,以及本文提出的生态系统生成内容（EGC）。本文提出CMR+FBS方法模型,分析了功能任务与内容描述之间的转换关系,并将CMR+FBS模型应用于百度智能音箱项目的研究中,对其唤醒功能的设计进行了分析。结论 FBS模型与CMR模型的结合能够支持高度灵活的智能体产品设计和数据服务的交互设计,CMR模型是提供高满意度用户体验的关键因素。寻求功能任务需求与构建用户生成内容的人机交互（HRI）关系是智能产品交互设计的新方法。     

无人驾驶车多种空间人类移动性交互设计研究

目的探讨无人驾驶车在智能交通系统、大数据、人工智能等技术支持下,对人类移动性的范式拓展与设计思考,研究新型人类移动性下无人驾驶车的交互设计方法。方法采用文献调查法、田野调查法和用户参与式设计方法进行分析研究。结果无人驾驶车对人类移动性的拓展包含信息转化,时空维度转换,固有信息与即生信息、转化信息构成了人类新的社交网络以及移动性的内容知识图谱。链接物资流、信息流和资金流的人类移动性构建在多种空间的灵活信息架构中。结论新型人类移动性的无人驾驶车交互设计,将交互内容、功能、媒介的设计,与人类移动性的数据采集、数据处理、数据应用相映射,交互模型中人的身份变得多元,人类群体移动性的交互模式形成新的交互行为逻辑,交互环境由人工智能数字环境和人类智能非数字环境共同构成混合智能的交互样态,信息架构基于自动驾驶形成自适应用户自产生内容UGC前馈和无人驾驶车专业生产内容PGC反馈的智能信息,新的人类移动性催生出由交互载体、功能、内容三要素构成的新的人机交互范式。     

Plasma characteristics of direct current enhanced cylindrical inductively coupled plasma source

Experimental results of a direct current enhanced inductively coupled plasma (DCE-ICP) source which consists of a typical cylindrical ICP source and a plate-to-grid DC electrode are reported.With the use of this new source,the plasma characteristic parameters,namely,electron density,electron temperature and plasma uniformity,are measured by Langmuir floating double probe.It is found that DC discharge enhances the electron density and decreases the electron temperature,dramatically.Moreover,the plasma uniformity is obviously improved with the operation of DC and radio frequency (RF) hybrid discharge.Furthermore,the nonlinear enhancement effect of electron density with DC + RF hybrid discharge is confirmed.The presented observation indicates that the DCE-ICP source provides an effective method to obtain high-density uniform plasma,which is desirable for practical industrial applications.     

Effects of direct current discharge on the spatial distribution of cylindrical inductively-coupled plasma at different gas pressures

Stable operations of single direct current(DC) discharge, single radio frequency(RF) discharge and DC?+?RF hybrid discharge are achieved in a specially-designed DC enhanced inductivelycoupled plasma(DCE-ICP) source. Their plasma characteristics, such as electron density,electron temperature and the electron density spatial distribution profiles are investigated and compared experimentally at different gas pressures. It is found that under the condition of single RF discharge, the electron density distribution profiles show a ‘convex' shape and ‘saddle' shape at gas pressures of 3 m Torr and 150 m Torr respectively. This result can be attributed to the transition of electron kinetics from nonlocal to local kinetics with an increase in gas pressure.Moreover, in the operation of DC?+?RF hybrid discharge at different gas pressures, the DC discharge has different effects on plasma uniformity. The plasma uniformity can be improved by modulating DC power at a high pressure of 150 m Torr where local electron kinetics is dominant,whereas plasma uniformity deteriorates at a low pressure of 3 m Torr where nonlocal electron kinetics prevails. This phenomenon, as analyzed, is due to the obvious nonlinear enhancement effect of electron density at the chamber center, and the inherent radial distribution difference in the electron density with single RF discharge at different gas pressures.