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1.
Transport models cannot simultaneously explain very recent data on pion multiplicities and pion charged ratios from central collision of Sn+Sn at 0.27 A GeV.This stimulates further investigations on the pion dispersion relation,in-medium Nπ→Δ cross sections,and Δ→Nπ decay widths near the threshold energy or at subthreshold energy of pion production in isospin asymmetric nuclear matter.In this study,the pion dispersion relation,in-medium Nπ→Δ cross section,and Δ→Nπ decay width near the threshold energy are investigated in isospin asymmetric nuclear matter by using the one-boson-exchange model.With the consideration of the energy conservation effect,the in-medium Nπ→Δ cross sections are enhanced at s1/2 <1.11 GeV in a nuclear medium.The prediction of pion multiplicity and π-/π+ ratios near the threshold energy could be modified if this effect is considered in transport model simulations.  相似文献   
2.
使用元素分析仪进行土壤、沉积物样品碳、氮含量检测时,样品前处理过程(烘干和酸化)、包样质量以及参考标准品等因素均会对检测结果造成影响.试验结果表明:酸化导致氮百分质量的测定结果降低2.6%~40.0%,碳百分质量的测定受包样质量的影响较大,使用的校正标准与被测样品越相似,校正结果越准确.  相似文献   
3.
The transmissions of oxygen ions through Al2O3 nanocapillaries each 50 nm in diameter and 10 μm in length at a series of different tilt angles are measured,where the ions with energies ranging from 10 to 60 keV and charge states from 1 up to 6 are involved.The angular distribution and the transmission yields of transported ions are investigated.Our results indicate both the existence of a guiding effect when ions pass through the capillary and a significant dependence of the ion transmission on the energy and the charge state of the ions.The guiding effects are observed to be enhanced at lower projectile energies and higher charge states.Meanwhile,the results also exhibit that the transmission yields increase as the tilt angle decreases at a given energy and charge state.  相似文献   
4.
The L-shell x-ray yields of Zr and Mo bombarded by slow Ar16+ ions are measured. The energy of the Ar^16+ ions ranges from about 150 keV to 350 keV. The L-shell x-ray production cross sections of Zr and Mo are extracted from these yields data. The explanation of these experimental results is in the framework of the adiabatic direct- ionization and the binding energy modified BEA approximation. We consider, in the slow asymmetric collisions such as Ar and Mo/Zr, the transient united atoms (UA) are formed during the ion-surface interaction and the direct-ionization is the main mechanism for the inner-shell vacancy production. Generally, the theoretical results are in good agreement with the experimental data.  相似文献   
5.
介绍了使用位置灵敏技术和飞行时间方法研究中低能低电荷态离子-原子碰撞过程中转移电离与单电子俘获过程.对于确定的入射离子电荷态,通过理论分析及与实验数据对比给出了转移电离与单电子俘获截面比RTS随着入射离子速度VP的变化规律和转移电离过程中电离的电子主要来自靶原子的最外亚壳层. 关键词: 转移电离 逃离半径 电离半径 俘获半径  相似文献   
6.
高电荷态离子Arq+入射在金属表面形成靶原子X射线谱   总被引:3,自引:3,他引:0  
本文报道低能高电荷Ar12+、Ar13+ 、Ar14+离子与金属Mo表面作用过程中Mo原子受激发射X射线和X射线强度随入射能量变化的实验结果.结果表明,低速高电荷离子与金属表面原子相互作用可有效地激发靶原子或靶离子内壳层电子而发射X射线.  相似文献   
7.
肝素化壳聚糖季铵盐/壳聚糖复合膜抗凝血性能的研究   总被引:14,自引:1,他引:13  
以壳聚糖季铵盐,壳聚糖为基本原材料,选用戊二醛为交剂剂及固定剂,制备一种物理机械性能较优的抗凝血材料。探讨了戊二醛及肝素钠两者用量对肝素化程度及血液生的影响。  相似文献   
8.
In this paper a projectile ions recoil ions coincidence technique is employed to investigate the target ionization and projectile charge state changing processes in the collision of 0.22-6.35 MeV Cq^+ (q = 1 - 4) ions with argon atoms. The partial cross section ratios of the double, triple, quadruplicate ionization to the single ionization (or the single capture) of argon associated with single electron loss (or single electron capture) by the projectile are measured and compared with the previous experimental results. In the present experiment, it is observed that the ratios of ionization cross sections R associated with single loss and single capture depend strongly on the projectile charge state and vary significantly with different reaction channels as impact energy increases. In addition, this paper gets empirical scaling laws for the ionization cross section ratios R corresponding to the projectile single loss and finds that the ratios of the double ionization to the single ionization associated with single electron capture remain constant in the present energy range.  相似文献   
9.
本实验是在中国科学院兰州近代物理研究所, 国家实验室的重离子加速器上完成的. 实验用ORTEC公司生产的HPGe X射线探测器测量了84.5MeV的12C4+离子轰击Cu, Mo, Ag, Cd, In, Sn, W和Au金属靶产生的K壳层特征X射线谱, 计算了Kβ与Kα-X射线强度的比值, 并将结果与Scofield用Hartree-Fock-Slater模型计算出的理论值与用其它方法 (如: 衰变幅射, 用光子, 电子, 质子等粒子与靶相互作用) 得到的实验值进行了比较. 比较结果表明用84.5MeV的12C4+离子轰击Cu, Mo, Ag, Cd, In, Sn, W和Au金属靶产生的Kβ与Kα-X射线强度比值比理论值和其它实验值要大许多.  相似文献   
10.
<正>This paper reports that the transmission of O6+ ions with energy of 150keV through capillaries in an uncoated Al2O3 membrane was measured,and agreements with previously reported results in general angular distribution of the transmitted ions and the transmission fractions as a function of the tilt angle well fitted to Gaussian-like functions were observed.Due to using an uncoated capillary membrane,ourψc is larger than that using a gold-coated one with a smaller value of(?),which suggests a larger equilibrium charge Qin our experiment.The observed special width variation with time and a larger width than that using a smaller(?) were qualitatively explained by using mean-field classical transport theory based on a classical-trajectory Monte Carlo simulation.  相似文献   
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