The stabilization ratios R for double-electron transfer, i.e., the cross section ratios of true double capture to total double-electron transfer, are measured in O^6＋ ＋He, Ne and Ar collisions at 6 keV/u. A high R v...The stabilization ratios R for double-electron transfer, i.e., the cross section ratios of true double capture to total double-electron transfer, are measured in O^6＋ ＋He, Ne and Ar collisions at 6 keV/u. A high R value about 68% is obtained for the He target, while for the Ar target, the R value is only 8%. The high R value for the He target is due to the significant direct population of the （2l, nl′ ） configurations with high n. For the Ar target, the （quasi）symmetric configurations （3l, nl′） lead to the much lower R value. Neglecting the core effects, the O^6＋ ion can be taken as a bare ion C^6＋ except the occupied ls shell, and then the measured R values are compared with previous experimental results of C^6＋ projectile ions at Ne and Ar target, while the occupied ls shell for the C^6＋ ＋He collisions. similar impact velocity. It yields good agreement with the O^6＋ ＋He system results in a higher R value than that in展开更多
The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47)...The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method(MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon(TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions.展开更多
目的探讨在超声引导下运用改良赛丁格技术行经外周静脉穿刺中心静脉置管(peripherally inserted central catheter,PICC)肿瘤患者的护理方法。方法回顾性分析并总结2011年9月至2012年3月陕西省肿瘤医院收治的采用超声引导下改良赛丁格...目的探讨在超声引导下运用改良赛丁格技术行经外周静脉穿刺中心静脉置管(peripherally inserted central catheter,PICC)肿瘤患者的护理方法。方法回顾性分析并总结2011年9月至2012年3月陕西省肿瘤医院收治的采用超声引导下改良赛丁格技术行PICC置管的112例肿瘤患者的临床资料。结果 112例患者中,105例患者穿刺置管成功,4例患者送管不顺利,经调整无效,再次选择血管穿刺后送管顺利;3例患者导管移位至颈静脉,经调整后顺利到位。结论在超声引导下运用改良赛丁格技术行PICC,置管成功率高,患者并发症少,值得在临床推广应用。展开更多
The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the c...The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the constants of 0.514-0.05, 0.204-0.03, 0.064-0.03 and 0.024-0.01 in this region. The significance of the multi-electron process in highly charged ions （HCIs） with argon collisions is demonstrated （σ^ME/σ^SC as high as 0.794-0.06）. In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model （MCBM）, the extended classical over-the-barrier model （ECBM） and the semiempirical scaling laws （SL）. The result is compared with these classical models and with our previous work of ^13C^6＋ -Ne collisions [Chin. Phys. Lett. 23 （2006） 95].展开更多
The characteristic L1, Lα, Lβ and Lγ x-rays of Au and energy shifts produced by 20-50 MeV ^16O^5＋ beams on a thick Au film are measured with a Si （Li） detector. Cross-section ratios of σ（Ll）/σ（Lα）, σ（L...The characteristic L1, Lα, Lβ and Lγ x-rays of Au and energy shifts produced by 20-50 MeV ^16O^5＋ beams on a thick Au film are measured with a Si （Li） detector. Cross-section ratios of σ（Ll）/σ（Lα）, σ（Lβ）/σ（Lβ） and σ（Lγ）/σ（Lα） versus O^5＋ energy show that consistent calculations yield considerably better agreements. Energy shifts L1, Lα, Lβ and Lγ x-rays of Au target increase with more incidence energy. The main application for these measurements is multi-element trace analysis through particle induced x-ray emission.展开更多
采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 p A/mm^2～14.3 n A/mm^2范围内改变入射流强,利用1 500 e V电子束入射上述绝缘平行板,实验研究了上述平行板对电子...采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 p A/mm^2～14.3 n A/mm^2范围内改变入射流强,利用1 500 e V电子束入射上述绝缘平行板,实验研究了上述平行板对电子束的导向行为。实验发现,上述电子束通过上述平行板时存在明显的导向现象,其导向行为与束流流强和绝缘材质无关。据此,可排除绝缘平行板内表面沉积电荷自组织充放电过程中,以绝缘材料的面电阻和体电阻对地泄放的线性形式放电过程。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10304019 and 10874188. The authors would like to acknowledge the researchers in the ECRIS group for their excellent beam extracting work.
文摘The stabilization ratios R for double-electron transfer, i.e., the cross section ratios of true double capture to total double-electron transfer, are measured in O^6＋ ＋He, Ne and Ar collisions at 6 keV/u. A high R value about 68% is obtained for the He target, while for the Ar target, the R value is only 8%. The high R value for the He target is due to the significant direct population of the （2l, nl′ ） configurations with high n. For the Ar target, the （quasi）symmetric configurations （3l, nl′） lead to the much lower R value. Neglecting the core effects, the O^6＋ ion can be taken as a bare ion C^6＋ except the occupied ls shell, and then the measured R values are compared with previous experimental results of C^6＋ projectile ions at Ne and Ar target, while the occupied ls shell for the C^6＋ ＋He collisions. similar impact velocity. It yields good agreement with the O^6＋ ＋He system results in a higher R value than that in
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1832126 and 11874051)the National Key Research and Development Program of China(Grant No.2017YFA0402300)。
文摘The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method(MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon(TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions.
文摘目的探讨在超声引导下运用改良赛丁格技术行经外周静脉穿刺中心静脉置管(peripherally inserted central catheter,PICC)肿瘤患者的护理方法。方法回顾性分析并总结2011年9月至2012年3月陕西省肿瘤医院收治的采用超声引导下改良赛丁格技术行PICC置管的112例肿瘤患者的临床资料。结果 112例患者中,105例患者穿刺置管成功,4例患者送管不顺利,经调整无效,再次选择血管穿刺后送管顺利;3例患者导管移位至颈静脉,经调整后顺利到位。结论在超声引导下运用改良赛丁格技术行PICC,置管成功率高,患者并发症少,值得在临床推广应用。
基金Supported by the National Natural Science Foundation of China under Grant Nos 10304019,10134010 and 10375080.
文摘The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the constants of 0.514-0.05, 0.204-0.03, 0.064-0.03 and 0.024-0.01 in this region. The significance of the multi-electron process in highly charged ions （HCIs） with argon collisions is demonstrated （σ^ME/σ^SC as high as 0.794-0.06）. In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model （MCBM）, the extended classical over-the-barrier model （ECBM） and the semiempirical scaling laws （SL）. The result is compared with these classical models and with our previous work of ^13C^6＋ -Ne collisions [Chin. Phys. Lett. 23 （2006） 95].
文摘The characteristic L1, Lα, Lβ and Lγ x-rays of Au and energy shifts produced by 20-50 MeV ^16O^5＋ beams on a thick Au film are measured with a Si （Li） detector. Cross-section ratios of σ（Ll）/σ（Lα）, σ（Lβ）/σ（Lβ） and σ（Lγ）/σ（Lα） versus O^5＋ energy show that consistent calculations yield considerably better agreements. Energy shifts L1, Lα, Lβ and Lγ x-rays of Au target increase with more incidence energy. The main application for these measurements is multi-element trace analysis through particle induced x-ray emission.
文摘采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯(Teflon)、酚醛树脂(电木)和聚甲醛板(赛钢板),并在15 p A/mm^2～14.3 n A/mm^2范围内改变入射流强,利用1 500 e V电子束入射上述绝缘平行板,实验研究了上述平行板对电子束的导向行为。实验发现,上述电子束通过上述平行板时存在明显的导向现象,其导向行为与束流流强和绝缘材质无关。据此,可排除绝缘平行板内表面沉积电荷自组织充放电过程中,以绝缘材料的面电阻和体电阻对地泄放的线性形式放电过程。
