Systematic calculations and assessments are performed for the magnetic dipole(M1)transition energies and rates between the ^(2)F^(o)_(5/2,7/2) levels in the ground configuration 4d104f along the Ag-like isoelectronic ...Systematic calculations and assessments are performed for the magnetic dipole(M1)transition energies and rates between the ^(2)F^(o)_(5/2,7/2) levels in the ground configuration 4d104f along the Ag-like isoelectronic sequence with 62≤Z≤94 based on the second-order many-body perturbation theory implemented in the Flexible Atomic Code.The electron correlations,Breit interaction and quantum electrodynamics effects are taken into account in the present calculations.The accuracy and reliability of our results are evaluated through comprehensive comparisons with available measurements and other theoretical results.For transition energies,our results are in good agreement with the recent experimental data obtained from the electron beam ion traps within 0.18%.The maximum discrepancy between our results and those obtained with the large-scale multiconfiguration Dirac–Hartee–Fock calculations by Grumer et al.[Phys.Rev.A 89062501(2014)]is less than 0.13%along the isoelectronic sequence.Furthermore,the corresponding M1 transition rates are also reported.The present results can be used as the benchmark and useful for spectra simulation and diagnostics of astrophysical and fusion plasmas.展开更多
复合绝缘子的酥朽老化难以跟踪和预测,且会导致绝缘子断串,严重危害电力系统的安全运行。主流观点认为酥朽老化起源于护套—芯棒内界面失效,然而,在一起500kV线路绝缘子异常温升故障中,发现内界面基本完好。该文开展了现场故障绝缘子样...复合绝缘子的酥朽老化难以跟踪和预测,且会导致绝缘子断串,严重危害电力系统的安全运行。主流观点认为酥朽老化起源于护套—芯棒内界面失效,然而,在一起500kV线路绝缘子异常温升故障中,发现内界面基本完好。该文开展了现场故障绝缘子样品的泄漏电流、局部放电、水扩散、工业计算机断层扫描(computed tomography scan,CT)、扫描电子显微镜(scanning electron microscopy,SEM)、傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)等测试,定位该绝缘子老化起始点位于伞裙—护套界面处的硅橡胶硫化缺陷,老化从伞裙根部向内侵蚀,扩散并穿透护套,造成护套—芯棒界面初步失效。若该绝缘子继续挂网运行,可能最终导致酥朽,该故障被判定为酥朽老化的早期表现。进一步研究发现,该批次绝缘子存在填料团聚、混料硫化不均、室温硫化硅橡胶(room temperature vulcanization,RTV)涂覆欠佳等缺陷,据此提出了制造改进建议。该文为绝缘子异常温升研究提供了详细案例分析,揭示了酥朽早期发展过程,有助于制造厂家和运行单位严控产品质量,预防恶性事故,保障电网安全运行。展开更多
基金the National Natural Science Foundation of China(Grant Nos.11874090,11934004,11404180,11604052,and 11774037)the National Key Research and Development Program of China(Grant No.2017YFA0402300).
文摘Systematic calculations and assessments are performed for the magnetic dipole(M1)transition energies and rates between the ^(2)F^(o)_(5/2,7/2) levels in the ground configuration 4d104f along the Ag-like isoelectronic sequence with 62≤Z≤94 based on the second-order many-body perturbation theory implemented in the Flexible Atomic Code.The electron correlations,Breit interaction and quantum electrodynamics effects are taken into account in the present calculations.The accuracy and reliability of our results are evaluated through comprehensive comparisons with available measurements and other theoretical results.For transition energies,our results are in good agreement with the recent experimental data obtained from the electron beam ion traps within 0.18%.The maximum discrepancy between our results and those obtained with the large-scale multiconfiguration Dirac–Hartee–Fock calculations by Grumer et al.[Phys.Rev.A 89062501(2014)]is less than 0.13%along the isoelectronic sequence.Furthermore,the corresponding M1 transition rates are also reported.The present results can be used as the benchmark and useful for spectra simulation and diagnostics of astrophysical and fusion plasmas.
文摘复合绝缘子的酥朽老化难以跟踪和预测,且会导致绝缘子断串,严重危害电力系统的安全运行。主流观点认为酥朽老化起源于护套—芯棒内界面失效,然而,在一起500kV线路绝缘子异常温升故障中,发现内界面基本完好。该文开展了现场故障绝缘子样品的泄漏电流、局部放电、水扩散、工业计算机断层扫描(computed tomography scan,CT)、扫描电子显微镜(scanning electron microscopy,SEM)、傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)等测试,定位该绝缘子老化起始点位于伞裙—护套界面处的硅橡胶硫化缺陷,老化从伞裙根部向内侵蚀,扩散并穿透护套,造成护套—芯棒界面初步失效。若该绝缘子继续挂网运行,可能最终导致酥朽,该故障被判定为酥朽老化的早期表现。进一步研究发现,该批次绝缘子存在填料团聚、混料硫化不均、室温硫化硅橡胶(room temperature vulcanization,RTV)涂覆欠佳等缺陷,据此提出了制造改进建议。该文为绝缘子异常温升研究提供了详细案例分析,揭示了酥朽早期发展过程,有助于制造厂家和运行单位严控产品质量,预防恶性事故,保障电网安全运行。
