本文研究了基于第一性原理平面波赝势及虚晶近似方法的镨(Pr)元素替位掺杂SmCo5体系(PrxSm1−xCo5)的体系的电子结构和磁性。采用CASTEP软件包,基于LDA + U并进行自旋极化计算,研究了不同掺杂参数下PrxSm1−xCo5 (x = 0 − 0.2)体系的能量...本文研究了基于第一性原理平面波赝势及虚晶近似方法的镨(Pr)元素替位掺杂SmCo5体系(PrxSm1−xCo5)的体系的电子结构和磁性。采用CASTEP软件包,基于LDA + U并进行自旋极化计算,研究了不同掺杂参数下PrxSm1−xCo5 (x = 0 − 0.2)体系的能量、分态密度、波尔磁矩等性质,研究表明,PrxSm1−xCo5体系的总态密度在−40 eV附近主要由s轨道贡献,总态密度在−20 eV附近主要由p轨道贡献,d轨道主要来自于Co及Pr/Sm原子,而f轨道贡献则来自于Pr/Sm原子且其自旋向下的密度远高于其自旋向上的密度,同时,随着镨元素掺杂比例的提高,晶格常数(a, c)以及晶胞体积(V)逐步增大,同时体系总能量逐步升高,同时,随着掺杂比例的不断变化,体系的波尔磁矩结果呈现出波动变化的特点,本文的研究有助于优化钐钴永磁体的设计。In this paper, the system energy of praseodymium (Pr) elemental substitution doped SmCo5 system (PrxSm1−xCo5) based on first-principles and virtual-crystal approximation method was studied. The energy, fractional density and Bohr magnetic moment of PrxSm1−xCo5 (x = 0 − 0.2) system under different doping parameters were studied by using CASTEP software package, based on LDA + U and spin polarization calculation, and the results show that the total density of states of the PrxSm1−xCo5 system is mainly contributed by the s orbital around −40 eV, the total density of states near −20 eV is mainly contributed by the p orbital, the d orbital is mainly contributed by Co and Pr/Sm atoms, and the f orbital is contributed by Pr/Sm atoms and its spin down density is much higher than its spin up density. At the same time, the total energy of the system is gradually decreasing, indicating that the system is more stable, and with the continuous change of the doping ratio, the Bohr magnetic moment results of the system show the characteristics of fluctuating changes, and the research in this paper is helpful to optimize the design of samarium cobalt permanent magnets.展开更多
目的对保定市新发现的1株pol区不能明确分型的HIV-1毒株(BD226AJ)进行近似全长基因组扩增,并分析其亚型、重组模式和基因特点。方法提取患者血浆中HIV-1RNA并逆转录为cDNA,使用近末端稀释法分2段对其进行近似全长基因组扩增并测序。使用...目的对保定市新发现的1株pol区不能明确分型的HIV-1毒株(BD226AJ)进行近似全长基因组扩增,并分析其亚型、重组模式和基因特点。方法提取患者血浆中HIV-1RNA并逆转录为cDNA,使用近末端稀释法分2段对其进行近似全长基因组扩增并测序。使用jpHMM和SimPlot 3.5软件对近似全长基因组序列进行重组模式和重组断点分析,采用MEGA 6.0软件分片段构建Neighbor-joining系统进化树进一步确认重组断点的准确性。构建该近似全长基因组序列及各亚型片段Neighbor-joining系统进化树,分析该毒株的亲本来源。结果经过近似全长基因组扩增、测序、序列拼接后,获得1条长度为8830 bp的HIV-1近似全长基因组序列。重组分析结果显示,该序列是由CRF01_AE和B亚型重组形成的,其近似全长基因组序列被3个断点分成了4个亚型片段,分别为ICRF01_AE(HXB2,823—4224 nt)、Ⅱ_(B)(HXB2,4225—5991 nt)、ⅢCRF01_AE(HX B2,5992—9295 nt)、ⅣB(HXB2,9296—9406 nt)。各亚型基因片段的系统进化树分析进一步表明该序列的可能亲本来源为CRF01_AE和B亚型。HIV BLAST的结果显示,该序列与CRF112_01B的相似性为96%,系统进化树分析进一步验证该序列与北京市男男性行为者(men who have sex with men,MSM)中的CRF112_01B序列聚集。结论本研究在保定市MSM人群中发现了1例由CRF01_AE和B亚型重组的新型重组毒株CRF112_01B,提示HIV-1CRF112_01B已通过MSM人群传入河北,并开始在保定市传播,因此加强该亚型或者类似新型毒株的监测,对有关部门采取针对性防控措施和遏制新型重组毒株在本地区的传播和流行具有重要意义。展开更多
文摘本文研究了基于第一性原理平面波赝势及虚晶近似方法的镨(Pr)元素替位掺杂SmCo5体系(PrxSm1−xCo5)的体系的电子结构和磁性。采用CASTEP软件包,基于LDA + U并进行自旋极化计算,研究了不同掺杂参数下PrxSm1−xCo5 (x = 0 − 0.2)体系的能量、分态密度、波尔磁矩等性质,研究表明,PrxSm1−xCo5体系的总态密度在−40 eV附近主要由s轨道贡献,总态密度在−20 eV附近主要由p轨道贡献,d轨道主要来自于Co及Pr/Sm原子,而f轨道贡献则来自于Pr/Sm原子且其自旋向下的密度远高于其自旋向上的密度,同时,随着镨元素掺杂比例的提高,晶格常数(a, c)以及晶胞体积(V)逐步增大,同时体系总能量逐步升高,同时,随着掺杂比例的不断变化,体系的波尔磁矩结果呈现出波动变化的特点,本文的研究有助于优化钐钴永磁体的设计。In this paper, the system energy of praseodymium (Pr) elemental substitution doped SmCo5 system (PrxSm1−xCo5) based on first-principles and virtual-crystal approximation method was studied. The energy, fractional density and Bohr magnetic moment of PrxSm1−xCo5 (x = 0 − 0.2) system under different doping parameters were studied by using CASTEP software package, based on LDA + U and spin polarization calculation, and the results show that the total density of states of the PrxSm1−xCo5 system is mainly contributed by the s orbital around −40 eV, the total density of states near −20 eV is mainly contributed by the p orbital, the d orbital is mainly contributed by Co and Pr/Sm atoms, and the f orbital is contributed by Pr/Sm atoms and its spin down density is much higher than its spin up density. At the same time, the total energy of the system is gradually decreasing, indicating that the system is more stable, and with the continuous change of the doping ratio, the Bohr magnetic moment results of the system show the characteristics of fluctuating changes, and the research in this paper is helpful to optimize the design of samarium cobalt permanent magnets.
文摘目的对保定市新发现的1株pol区不能明确分型的HIV-1毒株(BD226AJ)进行近似全长基因组扩增,并分析其亚型、重组模式和基因特点。方法提取患者血浆中HIV-1RNA并逆转录为cDNA,使用近末端稀释法分2段对其进行近似全长基因组扩增并测序。使用jpHMM和SimPlot 3.5软件对近似全长基因组序列进行重组模式和重组断点分析,采用MEGA 6.0软件分片段构建Neighbor-joining系统进化树进一步确认重组断点的准确性。构建该近似全长基因组序列及各亚型片段Neighbor-joining系统进化树,分析该毒株的亲本来源。结果经过近似全长基因组扩增、测序、序列拼接后,获得1条长度为8830 bp的HIV-1近似全长基因组序列。重组分析结果显示,该序列是由CRF01_AE和B亚型重组形成的,其近似全长基因组序列被3个断点分成了4个亚型片段,分别为ICRF01_AE(HXB2,823—4224 nt)、Ⅱ_(B)(HXB2,4225—5991 nt)、ⅢCRF01_AE(HX B2,5992—9295 nt)、ⅣB(HXB2,9296—9406 nt)。各亚型基因片段的系统进化树分析进一步表明该序列的可能亲本来源为CRF01_AE和B亚型。HIV BLAST的结果显示,该序列与CRF112_01B的相似性为96%,系统进化树分析进一步验证该序列与北京市男男性行为者(men who have sex with men,MSM)中的CRF112_01B序列聚集。结论本研究在保定市MSM人群中发现了1例由CRF01_AE和B亚型重组的新型重组毒株CRF112_01B,提示HIV-1CRF112_01B已通过MSM人群传入河北,并开始在保定市传播,因此加强该亚型或者类似新型毒株的监测,对有关部门采取针对性防控措施和遏制新型重组毒株在本地区的传播和流行具有重要意义。
