Scintillators,which can convert high-energy particles(X-rays)into detectable lowenergy ultraviolet-visible-near-infrared photons,are essential components of X-ray detectors and show extensive practical applications in...Scintillators,which can convert high-energy particles(X-rays)into detectable lowenergy ultraviolet-visible-near-infrared photons,are essential components of X-ray detectors and show extensive practical applications in nondestructive detection and medical imaging.Traditionally,inorganic scintillators represented by CsI:Tl have achieved definite progress.However,the harsh preparation conditions,high production cost,and poor mechanical properties impede their potential development in the high-end X-ray imaging field.Organic-inorganic hybrid metal complexes could be excellent alternatives,by virtue of their structural and spectral tunability,good solution processability,and excellent photophysical properties.This review mainly focuses on eco-friendly lead-free metal(Mn^(2+),Cu^(+),Sb^(3+),Sn^(2+),Ge^(2+),Ln^(3+),etc.)complex scintillators.The luminescence mechanisms are introduced and the scintillation performance,such as light yield,limit of detection,imaging resolution,etc.,is highlighted.Moreover,the current challenges and perspectives in this emerging field are described.It is hoped to provide some theoretical guidance for the continuous development of the new scintillator systems.展开更多
The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investi...The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investigations on the interaction of the gadolinium ion (Gd3+) with malic acid (C4H6O5, a-hydroxyl dicarboxylic acid), in dilute aqueous solution for pH values between 5.5 and 7.5. Colourless gadolinium complexes of malate ions have no absorption band UV-visible, the indirect photometric detection (IPD) technique was used and studies have identified a major tri-nuclear complex of malate ion (﹣OOC-CH2-CHOH-COO﹣). The formation of this new colourless complex is derived from three Gd(III) ions that react with two malate ions and two hydronium ions (H3O+), giving for this colourless complex, a (3,2,2) composition and apparent stability constant depends on the acidity of the medium, with logK'322 = 18.88 ± 0.05 at pH = 6.30. To complement previous results and to propose a probable structure for this new complex detected in solution, studies of IR spectroscopy have been conducted to identify the chelation sites for both ligands. The results were analysed and show that this organometallic gadolinium complex, contains two different sites, respectively, two lateral tetradentate mono-nuclear sites and a single central bidentate mono-nuclear site. From these results, the reaction of formation, the stability constant and the probable structure of this new colourless organometallic gadolinium complex are proposed.展开更多
基于遗传算法的复杂网络社区探测是当前的研究热点.针对该问题,本文在分析网络模块性函数Q的局部单调性的基础上,给出一种快速、有效的局部搜索变异策略,同时为兼顾初始种群的精度和多样性以达到进一步提高搜索效率的目的,采用了标签传...基于遗传算法的复杂网络社区探测是当前的研究热点.针对该问题,本文在分析网络模块性函数Q的局部单调性的基础上,给出一种快速、有效的局部搜索变异策略,同时为兼顾初始种群的精度和多样性以达到进一步提高搜索效率的目的,采用了标签传播作为初始种群的产生方法;综上,提出了一个结合局部搜索的遗传算法(Genetic algorithm with local search,LGA).在基准网络及大规模复杂网络上对LGA进行测试,并与当前具有代表性的社区探测算法进行比较,实验结果表明了文中算法的有效性与高效性.展开更多
基金National Key R&D Program of China,Grant/Award Number:2023YFE0202500National Natural Science Foundation of China,Grant/Award Numbers:62375142,62005241。
文摘Scintillators,which can convert high-energy particles(X-rays)into detectable lowenergy ultraviolet-visible-near-infrared photons,are essential components of X-ray detectors and show extensive practical applications in nondestructive detection and medical imaging.Traditionally,inorganic scintillators represented by CsI:Tl have achieved definite progress.However,the harsh preparation conditions,high production cost,and poor mechanical properties impede their potential development in the high-end X-ray imaging field.Organic-inorganic hybrid metal complexes could be excellent alternatives,by virtue of their structural and spectral tunability,good solution processability,and excellent photophysical properties.This review mainly focuses on eco-friendly lead-free metal(Mn^(2+),Cu^(+),Sb^(3+),Sn^(2+),Ge^(2+),Ln^(3+),etc.)complex scintillators.The luminescence mechanisms are introduced and the scintillation performance,such as light yield,limit of detection,imaging resolution,etc.,is highlighted.Moreover,the current challenges and perspectives in this emerging field are described.It is hoped to provide some theoretical guidance for the continuous development of the new scintillator systems.
基金Projects(51703253,52103230,62275217)supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,China+4 种基金Project(2020GXLH-Z-010)supported by the Key Research and Development Program of Shaanxi Province,ChinaProject(cstc2020jcyjmsxmX0931)supported by Chongqing Science and Technology Fund,ChinaProjects(2020A1515110603,2021A1515010633)supported by Guangdong Basic and Applied Basic Research Foundation,ChinaProjects(202003N4059,202003N4060)supported by Ningbo Natural Science Foundation,ChinaProject(2020Z073053007)supported by Aerospace Science Foundation of China。
文摘The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investigations on the interaction of the gadolinium ion (Gd3+) with malic acid (C4H6O5, a-hydroxyl dicarboxylic acid), in dilute aqueous solution for pH values between 5.5 and 7.5. Colourless gadolinium complexes of malate ions have no absorption band UV-visible, the indirect photometric detection (IPD) technique was used and studies have identified a major tri-nuclear complex of malate ion (﹣OOC-CH2-CHOH-COO﹣). The formation of this new colourless complex is derived from three Gd(III) ions that react with two malate ions and two hydronium ions (H3O+), giving for this colourless complex, a (3,2,2) composition and apparent stability constant depends on the acidity of the medium, with logK'322 = 18.88 ± 0.05 at pH = 6.30. To complement previous results and to propose a probable structure for this new complex detected in solution, studies of IR spectroscopy have been conducted to identify the chelation sites for both ligands. The results were analysed and show that this organometallic gadolinium complex, contains two different sites, respectively, two lateral tetradentate mono-nuclear sites and a single central bidentate mono-nuclear site. From these results, the reaction of formation, the stability constant and the probable structure of this new colourless organometallic gadolinium complex are proposed.
文摘基于遗传算法的复杂网络社区探测是当前的研究热点.针对该问题,本文在分析网络模块性函数Q的局部单调性的基础上,给出一种快速、有效的局部搜索变异策略,同时为兼顾初始种群的精度和多样性以达到进一步提高搜索效率的目的,采用了标签传播作为初始种群的产生方法;综上,提出了一个结合局部搜索的遗传算法(Genetic algorithm with local search,LGA).在基准网络及大规模复杂网络上对LGA进行测试,并与当前具有代表性的社区探测算法进行比较,实验结果表明了文中算法的有效性与高效性.
