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Generation and Distribution of Fast Atomic Species(N^+,N_f)in Nitrogen Glow Discharge 被引量:1
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作者 张连珠 于威 +2 位作者 韩理 赵占强 傅广生 《Plasma Science and Technology》 SCIE EI CAS CSCD 2006年第6期670-674,共5页
Using a combination of the Monte Carlo models of fast electrons, of molecular ions (N+) and of atomic species (N^+, Nf), the influence of the discharge pressure (P) and voltage (Vc) on the energy distributio... Using a combination of the Monte Carlo models of fast electrons, of molecular ions (N+) and of atomic species (N^+, Nf), the influence of the discharge pressure (P) and voltage (Vc) on the energy distributions of fast atomic species (N^+, Nf) produced by e^--N2s and N2^+- N2s dissociation reactions at the cathode in a nitrogen dc glow discharge was investigated. Both the angular distributions and the density distributions along the radius of the species (N^+, Nf) produced by the two dissociations at the cathode were calculated. The results show that: (1) there is an optimum discharge condition for P and Vc in order to obtain the species (N^+, Nf) at the cathode with high a density and energy, (2) when the voltage is above 800 V, the species (N^+, Nf) bombarding the cathode are mainly produced by the N^+-N2s dissociation, whereas when the voltage is below 300 V, they are mainly produced by the e-N2s dissociation, and (3) at high Voltages the incident angles of a considerable number of Nf into the cathode are quite small. The density of the species (N^+ Nf) at the cathode increases with the voltage, and when the pressure goes up to about 133 Pa, it decreases with the increasing pressure. 展开更多
关键词 nitrogen dc glow discharge Monte Carlo simulation fast nitrogen atomic species
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Interference effects on the photoionization cross sections between two neighbouring atoms:nitrogen as an example
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作者 吴建华 袁建民 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第12期5283-5290,共8页
Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than o... Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than or comparable to the de Broglie wave length of the ionized electrons. As an example, the single atomic nitrogen ionization cross section and the total cross sections of two nitrogen atoms with coherently added photoionization amplitudes are calculated from the threshold to about А (1 А=0.1 nm) of the photon energy. The photoionization cross sections of atomic nitrogen are obtained by using the close-coupling R-matrix method. In the calculation 19 states are included. The ionization energy of the atomic nitrogen and the photoionization cross sections agree well with the experimental results. Based on the R-matrix results of atomic nitrogen, the interference effects between two neighbouring nitrogen atoms are obtained. It is shown that the interference effects are considerable when electrons are ionized just above the threshold, even for the separations between the two atoms are larger than two times of the bond length of N2 molecules. Therefore, in hot and dense samples, effects caused by the coherent interference between the neighbours are expected to be observable for the total photoionization cross sections. 展开更多
关键词 interference effect photoionization cross section nitrogen atom
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Copper-Mediated Selective Multiple Inert Chemical Bonds Cleavage for Cyanation of Indoles via Tandem Carbon and Nitrogen Atom Transfer
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作者 Shimin Xie Fangfang Cai +3 位作者 Lixin Liu Lebin Su Jianyu Dong Yongbo Zhou 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2024年第19期2299-2304,共6页
Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-ec... Comprehensive Summary The activation of inert chemical bonds is an exciting area of research in chemistry because it enables the direct utilization of readily available starting materials and promotes atom-and step-economic synthesis.Undoubtedly,selectively activating and transforming multiple inert chemical bonds is an even more intriguing and demanding task in synthetic chemistry.However,due to its inherent complexity and extreme challenges,this endeavour is rarely accomplished.We report a copper-mediated complete cleavage and selective transformation of multiple inert chemical bonds of three easily available feedstocks,i.e.,a sp^(2)C—H bond in indoles,three sp^(3)C—H bonds and one C—N bond in a methyl carbon atom in TMEDA,and the C≡N triple bond in CH_(3)CN.This reaction proceeds via tandem carbon and nitrogen atom transfer,and allows for the direct and efficient cyanation of indoles,presenting a simple and direct alternative for synthesizing 3-cyanoindoles. 展开更多
关键词 Multiple inert chemical bonds Bond cleavage Carbon and nitrogen atom transfer Cleavage reactions Oxidation Copper Cyanation IndoleSelectivity
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Enlarged interlayer spacing and enhanced capacitive behavior of a carbon anode for superior potassium storage 被引量:9
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作者 Xiaodong Shi Yida Zhang +4 位作者 Guofu Xu Shan Guo Anqiang Pan Jiang Zhou Shuquan Liang 《Science Bulletin》 SCIE EI CSCD 2020年第23期2014-2021,M0004,共9页
Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbona... Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbonaceous electrodes present sluggish kinetics, resulting in unsatisfactory cycling stability and poor rate capability. Herein, we demonstrate that the synergistic effects of the enlarged interlayer spacing and enhanced capacitive behavior induced by the co-doping of nitrogen and sulfur atoms into a carbon structure(NSC) can improve its potassium storage capability. Based on the capacitive contribution calculations, electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique, and density functional theory results, the NSC electrode is found to exhibit favorable electronic conductivity,enhanced capacitive adsorption behavior, and fast K+ ion diffusion kinetics. Additionally, a series of exsitu characterizations demonstrate that NSC exhibits superior structural stability during the(de)potassiation process. As a result, NSC displays a high reversible capacity of 302.8 mAh g-1 at 0.1 Ag-1 and a stable capacity of 105.2 m Ahg-1 even at 2 Ag-1 after 600 cycles. This work may offer new insight into the effects of the heteroatom doping of carbon materials on their potassium storage properties and facilitate their application in PIBs. 展开更多
关键词 Potassium-ion batteries Co-doping of nitrogen and sulfur atoms Carbon interlayer Capacitive behavior Synergistic effects
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