期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
非简并双光子Tavis-Cummings模型中量子态保真度及原子间关联 被引量:10
1
作者 刘堂昆 王继锁 詹明生 《量子电子学报》 CAS CSCD 北大核心 2001年第5期438-444,共7页
运用全量子理论研究了双模真空光场作用下的非简并双光子T-C模型体系中量子态保真度和原子间关联特性,讨论了不同的原子初态条件下,原子间偶极相互作用对体系中的量子态保真度和原子间关联的影响.结果表明:初始各自处在激发态的... 运用全量子理论研究了双模真空光场作用下的非简并双光子T-C模型体系中量子态保真度和原子间关联特性,讨论了不同的原子初态条件下,原子间偶极相互作用对体系中的量子态保真度和原子间关联的影响.结果表明:初始各自处在激发态的无关联的两原子在双模真空光场和原子间的偶极相互作用下呈现关联特性;初始各自处在基态的无关联的两原子在相互作用下无关联,并且系统、光场和原子三者的量子态在演化过程中不失真. 展开更多
关键词 非简并双光子T-C模型 量子态保真度 原子间关联 量子光学
下载PDF
二维和三维氢分子中原子间的电子关联的比较
2
作者 王新强 《原子与分子物理学报》 CAS CSCD 北大核心 1997年第4期629-634,共6页
讨论了非正交基(类氢原子的1s态)和正交基下,二维和三维氢分子的基态波函数中,反映原子间电子关联大小的离子键成分与共价键成分的权重之比η随核间距R的变化情况,分析了两种基下存在差别的原因,认为正交基下反映的情况更为客... 讨论了非正交基(类氢原子的1s态)和正交基下,二维和三维氢分子的基态波函数中,反映原子间电子关联大小的离子键成分与共价键成分的权重之比η随核间距R的变化情况,分析了两种基下存在差别的原因,认为正交基下反映的情况更为客观,并得出二维氢分子中原子间的电子关联明显强于三维氢分子中原子间的电子关联这一重要结论。 展开更多
关键词 二维 三维 氢分子 原子间电子关联
下载PDF
Recent advances on stimuli-responsive macromolecular magnetic resonance imaging (MRI) contrast agents 被引量:2
3
作者 Jinming Hu Shiyong Liu 《Science China Chemistry》 SCIE EI CAS CSCD 2018年第9期1110-1122,共13页
Magnetic resonance imaging(MRI) has been extensively used in clinical diagnosis and currently over 30% MRI runs are performed in the presence of contrast agents. However, commercially available contrast agents origina... Magnetic resonance imaging(MRI) has been extensively used in clinical diagnosis and currently over 30% MRI runs are performed in the presence of contrast agents. However, commercially available contrast agents originated from small molecules typically exhibit relatively low relaxivities and insufficient circulation time. Therefore, there is a long pursuit to develop new contrast agents with high relaxivities to discriminate pathological tissues from normal ones. Compared with small molecule MRI contrast agents, the incorporation of small molecule contrast agents into macromolecular scaffolds allows for constructing macromolecular MRI contrast agents, remarkably elevating the relaxivities due in part to increased rotational correlation time(τR). Moreover, if the macromolecular scaffolds are responsive to external stimuli, the MRI signals could be selectively switched on at the desired sites(e.g., pathological tissues), further intensifying the imaging contrast. In this feature article, we outline the recent achievements in the fabrication of stimuli-responsive macromolecular MRI contrast agents. Specifically, macromolecular contrast agents being responsive to acidic p H, redox potentials, and other stimuli including photoirradiation, pathogens, and salt concentration are discussed. These smart contrast agents could affect either longitudinal(T1) or transverse(T2) relaxation times of water protons or other nuclei(e.g.,19 F), exhibiting enhanced signals in pathological tissues yet suppressed signals in normal ones and displaying promising potentials in in vitro and in vivo MRI applications. 展开更多
关键词 PH-RESPONSIVE redox-responsive contrast agents magnetic resonance imaging
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部