分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: In this paper, we report a newly developed Knudsen Cell injection system for SH-PermEBIT. This technique can overcome disadvantages of introducing organometallic gases and wired probes into EBIT and provide steady continuous injection. A specially designed vacuum line is used to ensure that the Knudsen Cell satisfies the vacuum level of SH-permEBIT. Using this system we successfully injected ytterbium into the SH-permEBIT and recorded a spectrum in the visible wavelength region.
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-05-09
摘要: For exploring more types of suitable polymeric membranes for application in alkaline fuel cells (AFCs), a series of 1,2-dimethylimidazolium functionalized poly(arylene ether sulfone)s containing 4-phenyl- pyridine units in the main chain (named as DIm-PPYPAES) were firstly synthesized as anion exchange membranes (AEMs) in this work. Proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize and confirm the chemical structure of the synthesized copolymers and the derived membranes. The DIm-PPYPAES membranes with different ionized levels ranging from 1.15 meq. g 1 to 1.77 meq. g 1, exhibited good thermal stability, solubility behavior and a relatively high level of hydroxide conductivity. The highest hydroxide conductivity of 83.35 mS cm 1 at 80 C was achieved for the DIm-PPYPAES-4 membrane with a moderate IEC of 1.77 meq. g 1. Moreover, after 15 days of treatment with a 2 M NaOH solution at 60 C, the DIm-PPYPAES membrane still exhibited relatively high ionic conductivity even above 10 mS cm 1 at 30 C and retained their integrated shapes.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: A serials of imidazolium functionalized poly(arylene ether sulfone) as anion exchange membranes (AEMs) for all-vanadium redox flow battery (VRB) application are synthesized successfully in this study. The AEMs obtained with different ionization levels, Im-PAES-0.5/0.7/1.1 (0.5/0.7/1.1 represents the different degrees of bromination, respectively) membranes are intensively characterized. Compared with commercial Nafion 117 membrane, the vanadium ion permeation values of AEMs are lower while their chemical stability in VO2+ are comparable. The ionic conductivities, vanadium ion permeability, stability of the membranes and their performance in VRB cells are greatly affected by ionic exchange capacity (IEC). In order to balance these important performance factors, the Im-PAES-0.7 membrane with a moderate IEC of 2.01 meq g 1 exhibits good stability, high ionic conductivity and low vanadium ion permeation, resulting in high voltage efficiencies (up to 87.5%), high coulombic efficiencies (up to 96.1%), as well as high energy efficiency. The VRB cell with the Im-PAES-0.7 membrane achieves comparable to or even slightly higher energy efficiency values (up to 81.7%) than those of Nafion 117 membranes (up to 78.9%) in the current density range of 60–120 mA cm 2. During 40 charge–discharge cycles at different current densities, the Im-PAES-0.7 anion exchange membrane exhibits a comparable short-term stability to Nafion 117 membrane.