Special issue on selected papers from CEPC 2020

The development of electric propulsion has taken decades and in fact,began flight testing as early as the 1960s.However,it was initially slow to develop as an alternative to chemical propulsion systems due to the lack of available on-board electrical power for space vehicles.Since the turn of this century,the booming satellite market,and in particular for small satellites,has driven the demand for propulsion systems with high specific impulse,precisely adjustable thrust,long lifetime,and adaptable for different kinds of small vehicles.At the same time,Hall,ion,arcjet and other forms of electric thruster technologies have reached a mature level,the success of in-orbit testing further stimulated the applications of electric propulsion technology.In recent years,a number of commercial compa-nies have proposed plans for small satellite constellations in low Earth orbit,providing broader opportunities for the development and application of electric propulsion technology.The age of electric propulsion has arrived.     

Special issue on selected papers from CEPC 2019

正The Chinese Electric Propulsion Conference(CEPC) is hosted by Chinese Society of Astronautics and began in 2005. It is the premier conference in the field of electrical propulsion in China. It is held once a year and is attended by leading researchers, specialists, and students in electric propulsion. This special issue contains selected papers from the 2019 Chinese Electric Propulsion Conference     

Special issue on selected papers from HVDP 2016

<正>This special issue contains selected papers from the 2016 National Conference on High Voltage and Discharge Plasmas(HVDP),which was hosted by the Plasmas and their Applications Committee,China Electrotechnical Society,and held in Beijing,China,on 26 and 27 November 2016.The conference was attended by over 430 delegates from 110 universities,research institutes and enterprises.In total,280 abstracts and 132 full papers have been submitted,giving a wonderful assembly of technical contributions from around China.     

Special issue on selected papers from HVDP 2020

正High-voltage and discharge plasma technology is playing an increasingly important role in the construction of national economy and social development,and has attracted extensive attention from both academia and industry. As a novel molecular activation method, discharge plasma can enable thermodynamically difficult reactions to occur under relatively mild conditions, and its effectiveness has successfully been demonstrated in gas cleaning and material surface treatment.     

Analysis of the single differential neutron scattering cross section from disordered systems by maximum entropy

A procedure for the analysis of neutron single-differential scattering cross sections measured by diffraction experiments in amorphous solid or liquid molecular systems is presented. The method incorporates a convenient scheme for applying the inelasticity or Placzek corrections up to a first order. A substantial improvement over conventional fitting procedures is illustrated by the analysis of a reactor and pulsed neutrons datasets. Finally, the dangers of performing oversimple corrections as well as the need of incorporating additional information in the separation between “self” and “distinct” terms is discussed.     

Determination of the neutron skin thickness from interaction cross section and charge-changing cross section for B,C, N,O, F isotopes

The effective neutron and proton root-meansquare radius of stable and unstable nuclei(~(12-15,17)B,~(12-20)C,~(14-21)N,~(16-24)O and ~(18-21,23-26)F) were deduced from the charge-changing cross section,σ_(cc),and the interaction cross sections,σ_I,by using a statistical abrasion-ablation model calculation.The extracted proton radii are in good agreement with the data from the Atomic Data and Nuclear Data Tables within the errors.Furthermore,we can observe that the neutron skin thickness increases monotonously with the increasing neutron number in these isotopes,which is consistent with the systematical trend of theoretical calculations.     

用旋转极坐标法在少投影条件下重建钢管截面图像

钢管的在线检测和控制是提高其质量的重要环节,也是目前亟待解决的难题.射线CT成像技术作为一种高效的图像检测手段,特别适合对钢管截面的尺寸参数进行检测和控制.本文利用旋转极坐标法在少投影条件下获得钢管截面的重建图像,该方法不仅减少了投影数目,缩短了数据采集时间,且加快了算法速度,节约了图像重建时间,大大减少钢管检测的时间.模拟试验和实际试验的结果均表明,旋转极坐标法的重建效果和重建时间基本可满足目前钢管在线检测和控制的要求,具有一定的理论意义和应用前景.     

从工业CT图像探测断面内边缘的小波分析方法

介绍了在工业计算机断层扫描成像（ＣＴ）中探测工件断面内边缘的小分析波方法，这种方法与从ＩＣＴ图像级的传统方法比较，具有噪声低和边缘突出的特点，可滤去ＩＣＴ图肿的非白噪声，这种方法也可用于医学ＣＴ等领域。