测量了20 ke V质子穿过倾斜角为+1?的聚碳酸酯微孔膜后,出射粒子的位置分布、相对穿透率以及电荷纯度随时间的演化.实验发现,能量电荷比E/q≈10~1k V的质子穿过绝缘纳米微孔的物理机理与E/q≈10~0k V和E/q≈10~2k V区域离子有显著不同....测量了20 ke V质子穿过倾斜角为+1?的聚碳酸酯微孔膜后,出射粒子的位置分布、相对穿透率以及电荷纯度随时间的演化.实验发现,能量电荷比E/q≈10~1k V的质子穿过绝缘纳米微孔的物理机理与E/q≈10~0k V和E/q≈10~2k V区域离子有显著不同.对于E/q≈10~1k V的质子穿过绝缘纳米微孔,存在一段相当长的导向建立之前(导向前)的过程,在该时期内出射质子及氢原子的特性和导向建立后的特性有很大差异.在导向前的演化过程中,我们可以观察到出射质子的峰位逐渐向孔轴向附近转移;出射氢原子由束流方向的尖峰以及孔轴向的主峰构成,峰位角保持基本不变且尖峰逐渐消失.这一过程的主要机理为微孔内表面以下的多次随机二体碰撞和近表面镜面反射两种传输方式逐步向电荷斑约束下的"导向效应"过渡的过程.对E/q≈10~1k V区间离子"导向前过程"的完整观测,使得对低能向中能过渡区间离子穿过绝缘微孔膜物理机制和图像有更深入和完整的认识,有助于约10 ke V离子微束的精确控制和应用.展开更多
An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advanta...An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.展开更多
The effect of source size and emission time on the proton-proton(p-p)momentum correlation function(Cpp(q))has been studied systematically.Assuming a spherical Gaussian source with space and time profile according to t...The effect of source size and emission time on the proton-proton(p-p)momentum correlation function(Cpp(q))has been studied systematically.Assuming a spherical Gaussian source with space and time profile according to the function S(r,t)~exp(-r2/2 r02-t/τ)in the correlation function calculation code(CRAB),the results indicate that one Cpp(q)distribution corresponds to a unique combination of source size r0 and emission timeτ.Considering the possible nuclear deformation from a spherical nucleus,an ellipsoidal Gaussian source characterized by the deformation parameter∈=ΔR/R has been simulated.There is almost no difference of Cpp(q)between the results of spherically and ellipsoidally shaped sources with small deformation.These results indicate that a unique source size r0 and emission time could be extracted from the p-p momentum correlation function,which is especially important for identifying the mechanism of twoproton emission from proton-rich nuclei.Furthermore,considering the possible existence of cluster structures within a nucleus,the double Gaussian source is assumed.The results show that the p-p momentum correlation function for a source with or without cluster structures has large systematical differences with the variance of r0 andτ.This may provide a possible method for experimentally observing the cluster structures in proton-rich nuclei.展开更多
Proton acceleration induced by a high-intensity ultraviolet laser interaction with a thin foil target was studied on an ultra-short KrF laser amplifier called LLG50 in China Institute of Atomic Energy （CIAE）. The ul...Proton acceleration induced by a high-intensity ultraviolet laser interaction with a thin foil target was studied on an ultra-short KrF laser amplifier called LLG50 in China Institute of Atomic Energy （CIAE）. The ultraviolet laser produced pulses with a high-contrast of 109, duration of 500 fs and energy of 30 mJ. The p-polarized laser was focused on a 2.1 #m gold foil by an off-axis parabola mirror （OAP） at an incident angle of 45°. The laser intensity was 1.2× 1017 W/cm2. The divergence angle for proton energy of 265 keV or higher was 30°, which was recorded by a CR39 detector covered with 2 μm aluminum foil in the target normal direction. The maximum proton energy recorded by a CR39 detector covered with a 4 μm aluminum foil was 440 keV, and the proton energy spectrum was measured by a proton spectrometer. The ultraviolet laser acquires a relatively lower hot electron temperature, which can be ascribed to the proportional relationship of Iλ2, but a higher hot electron density because of the higher laser absorption and critical density. Higher electron density availed to strengthen the sheath electric field, and increased the proton acceleration.展开更多
文摘测量了20 ke V质子穿过倾斜角为+1?的聚碳酸酯微孔膜后,出射粒子的位置分布、相对穿透率以及电荷纯度随时间的演化.实验发现,能量电荷比E/q≈10~1k V的质子穿过绝缘纳米微孔的物理机理与E/q≈10~0k V和E/q≈10~2k V区域离子有显著不同.对于E/q≈10~1k V的质子穿过绝缘纳米微孔,存在一段相当长的导向建立之前(导向前)的过程,在该时期内出射质子及氢原子的特性和导向建立后的特性有很大差异.在导向前的演化过程中,我们可以观察到出射质子的峰位逐渐向孔轴向附近转移;出射氢原子由束流方向的尖峰以及孔轴向的主峰构成,峰位角保持基本不变且尖峰逐渐消失.这一过程的主要机理为微孔内表面以下的多次随机二体碰撞和近表面镜面反射两种传输方式逐步向电荷斑约束下的"导向效应"过渡的过程.对E/q≈10~1k V区间离子"导向前过程"的完整观测,使得对低能向中能过渡区间离子穿过绝缘微孔膜物理机制和图像有更深入和完整的认识,有助于约10 ke V离子微束的精确控制和应用.
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061-A25-019)the Scientific Research Fund of Gansu Provincial Education Department(No.0601-25).
文摘An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5 -triaryl- 1H-imidazoles and 1,2,4,5 -tetraaryl- 1H- imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.
基金supported by the National Key R&D Program of China(No.2018YFA0404404)the National Natural Science Foundation of China(Nos.11925502,11935001,11961141003,11421505,11475244,and 11927901)+2 种基金the Shanghai Development Foundation for Science and Technology(No.19ZR1403100)the Strategic Priority Research Program of the CAS(No.XDB34030000)the Key Research Program of Frontier Sciences of the CAS(No.QYZDJ-SSW-SLH002).
文摘The effect of source size and emission time on the proton-proton(p-p)momentum correlation function(Cpp(q))has been studied systematically.Assuming a spherical Gaussian source with space and time profile according to the function S(r,t)~exp(-r2/2 r02-t/τ)in the correlation function calculation code(CRAB),the results indicate that one Cpp(q)distribution corresponds to a unique combination of source size r0 and emission timeτ.Considering the possible nuclear deformation from a spherical nucleus,an ellipsoidal Gaussian source characterized by the deformation parameter∈=ΔR/R has been simulated.There is almost no difference of Cpp(q)between the results of spherically and ellipsoidally shaped sources with small deformation.These results indicate that a unique source size r0 and emission time could be extracted from the p-p momentum correlation function,which is especially important for identifying the mechanism of twoproton emission from proton-rich nuclei.Furthermore,considering the possible existence of cluster structures within a nucleus,the double Gaussian source is assumed.The results show that the p-p momentum correlation function for a source with or without cluster structures has large systematical differences with the variance of r0 andτ.This may provide a possible method for experimentally observing the cluster structures in proton-rich nuclei.
基金supported by the Key Project of Chinese National Programs for Fundamental Research(973 Program)(No.2011CB808104)National Natural Science Foundation of China(Nos.10834008,11105234)
文摘Proton acceleration induced by a high-intensity ultraviolet laser interaction with a thin foil target was studied on an ultra-short KrF laser amplifier called LLG50 in China Institute of Atomic Energy （CIAE）. The ultraviolet laser produced pulses with a high-contrast of 109, duration of 500 fs and energy of 30 mJ. The p-polarized laser was focused on a 2.1 #m gold foil by an off-axis parabola mirror （OAP） at an incident angle of 45°. The laser intensity was 1.2× 1017 W/cm2. The divergence angle for proton energy of 265 keV or higher was 30°, which was recorded by a CR39 detector covered with 2 μm aluminum foil in the target normal direction. The maximum proton energy recorded by a CR39 detector covered with a 4 μm aluminum foil was 440 keV, and the proton energy spectrum was measured by a proton spectrometer. The ultraviolet laser acquires a relatively lower hot electron temperature, which can be ascribed to the proportional relationship of Iλ2, but a higher hot electron density because of the higher laser absorption and critical density. Higher electron density availed to strengthen the sheath electric field, and increased the proton acceleration.
