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Effect of H^- ion extraction on a plasma sheath under an external weak magnetic field

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Chinese Physics C 2013年第5期37卷 63-67页

作者：蓝朝晖彭宇飞杨振龙继东 Institute of Fluid Physics China Academy of Engineering Physics

The extraction of negative ions inevitably leads to the destruction of the original plasma state. To understand the effect of extraction on a plasma sheath under a weak magnetic filter field, the time-dependent behavior of H- ion extraction from a negative ion source has been studied by particle-in-cell simulation in the collisionless limit. The simulation results have shown that the plasma sheath would undergo a transient process, in which there exists an edge electrostatic wave that propagates counterclockwise along the wall with a velocity of 4 mm/ns until it reaches the other side of extraction aperture. The thickness of the plasma sheath and the plasma potential both increase greatly at the final quasi-steady-state. For comparison, the results of extracting positive ions are also given.

关键词： negative ion source plasma sheath ion extraction particle-in-cell simulation

Synthesis, Structure and ion extraction Properties of Novel Monooxa-diselkylene-1,ω-dioxy Substituted Calix[4]arene Derivatives

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Chinese Journal of Chemistry 2006年第5期24卷 674-680页

作者：秦大斌曾宪顺徐凤波李庆山张正之 State Key Laboratory of Elemento-organic Chemistry Nankai University Tianjin 300071 China School of Chemistry and Chemical Industry China East Normal University Nanchong Sichuan 637000 China

Novel macrocyclic monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a were synthesized by the reaction of calix[4]arene dibromides 1-5 with the disodium salt of bis（2-selenylethyl）ether in the yields between 28% and 64%. Their structures were characterized by proton and carbon NMR spectra. X-Ray structure analysis of la further confirmed the cone conformation of compounds 1a-5a. An interesting host-guest complex of la with dichloromethane via CH/π and C1/π interactions was elucidated. extraction experiments showed that these novel monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a had strong extraction ability towards mercury ion. The interaction of Hg^2＋with the calix ligand has also been investigated by 1^H NMR titration.

关键词： calixarene selenide NMR titration ion extraction

Radial and Angular Resolved Langmuir Probe Diagnosis of a Pulsed Vacuum Arc Plasma

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Plasma Science and Technology 2011年第6期13卷 689-692页

作者：陈磊马明旺黎明金大志谈效华戴晶怡杨林胡思得 Institute of Electronic Engineering China Academy of Engineering Physics Department of Engineering Physics Tsinghua University Institute of Nuclear Science and Technology Lanzhou University

Vacuum arc ion sources are known for delivering high currents of ion beams in many technological applications. There is a great need in the present ion accelerator injection research for a titanium vacuum arc source to produce high-ionized plasma, in which its parameter is extremely important to match the extractors geometry and the extraction voltage. In this paper, the radial and angular distributions of the titanium cathodic vacuum arc plasma parameters are measured by a cylindrical Langmuir probe and analyzed by the Druyvesteyn method from the I-V curves. The electron density ne is about 10^（17）m^（-3） and the effective electron temperature Tefr is in the range of 6.12-11.11 eV in the free expansion cup before the ion extraction. The measured distribution of ne over the expansion cross-section is non-uniform and axially unsymmetrical with its form similar to the Gaussian distribution, and most of the plasma is concentrated into an area whose radius is smaller than 5 mm. Teff has a nearly uniform distribution over the expansion cross-section during the discharge. The results of the plasma parameters＇ non-uniformity encourage the researchers to make some optimization designs to improve the parameter distributions, and then to facilitate ion extraction.

关键词： langmuir probe vacuum arc plasma ion extraction diagnosis

Selective Transport of Alkali-Metal Cations through Liquid Membranes by Non-Cyclic Carriers

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Chinese Journal of Chemistry 2002年第1期20卷 90-95页

作者：徐明宋恺吴骊珠张丽萍佟振合 Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100101 China

The emission spectra of a series of naphthalene end-labeled oligo-oxyethylene(N-P_n-N) and their facilitated transport of cations across liquid membranes have beeninvestigated. Alkali-metal cations enhance or inhibit the intramolecular excimer formation ofN-P_n-N remarkably, suggesting that the polyether chain of N-P_n-N in solution complexes with thecations, and the orientation of the terminal chromophores depends on the cation size and the lengthof the polyether chain. These compounds are able to act as carriers to facilitate transport ofalkali-metal cations through organic liquid membranes. The transport efficiencies are comparablewith those of cyclic carriers such as crown ethers, and show remarkable selectivity.

关键词： N-P_n-N excimer ion extraction cation transport