Photocatalytic water splitting has gained increasing attention, since it utilizes renewable resources, such as water and solar energy, to produce hydrogen. Using the first-principles density functional theory, we inve...Photocatalytic water splitting has gained increasing attention, since it utilizes renewable resources, such as water and solar energy, to produce hydrogen. Using the first-principles density functional theory, we investigate the properties of the single layer C_2N which was successfully synthesized. We reveal that monolayer C_2N has a substantial direct band gap of 2.45 eV. To regulate its band gap, four different nonmetal elements（B, O, P, and S） on the cation and anion sites are considered. Among them, B-doped N site is the most effective one, with the lowest formation energy and a band gap of 2.01 eV. P-doped N site is the next, with a band gap of 2.08 eV, though its formation energy is higher. The band alignments with respect to the water redox levels show that, for these two dopings, the thermodynamic criterion for the overall water splitting is satisfied. We therefore predict that B-or P-doped C_2N, with an appropriate band gap and an optimal band-edge position, would be a promising photocatalyst for visible-light water splitting.展开更多
针对现有指挥控制网络(command and control network,C2N)初始负载大多为基于节点,缺少边初始负载定义,结合边重要性及边层级,提出兼顾边重要性和边层级的C2N边初始负载。给出边度和自我网络边介数定义;结合改进桥接系数、边度和自我网...针对现有指挥控制网络(command and control network,C2N)初始负载大多为基于节点,缺少边初始负载定义,结合边重要性及边层级,提出兼顾边重要性和边层级的C2N边初始负载。给出边度和自我网络边介数定义;结合改进桥接系数、边度和自我网络边介数,提出边重要性新定义;接着给出边层级定义,结合边重要性和边层级,提出新的边初始负载定义;仿真分析了不同失效模型的抗毁性,结果表明该初始负载定义的级联失效模型具有更强的抗毁能力。展开更多
[目的]煤炭在我国能源结构中长期占据主导地位。随着全球气候治理进程加速,全球主要经济体都朝着碳中和目标快速迈进。此外,近年来我国核电新核准以及在建的机组数量始终保持增长态势,在全球范围内位列第一,核电显著的减排效应使“煤电...[目的]煤炭在我国能源结构中长期占据主导地位。随着全球气候治理进程加速,全球主要经济体都朝着碳中和目标快速迈进。此外,近年来我国核电新核准以及在建的机组数量始终保持增长态势,在全球范围内位列第一,核电显著的减排效应使“煤电改核电”(Coal to Nuclear,C2N)有望成为新的传统能源替代场景。文章通过分析C2N的发展现状,对C2N的关键问题进行研究,探究C2N的典型场景,对C2N在我国的发展前景进行展望,旨在为未来我国大规模煤电厂转型发展利用提供新思路。[方法]采用文献综述和比较分析的研究方法,梳理了C2N的发展情况,分析了国内外在C2N技术和实践方面的最新进展;同时,结合相关核电行业政策法规文件和煤电、核电厂部分技术参数对比,探讨了C2N的关键问题和应用场景。[结果]研究表明C2N的发展在理论上可行,但必须与其他类型能源协同发展,共同服务于我国的能源发展战略。未来,需要基于现有研究,结合技术进步、我国中长期能源电力流向、区域经济发展水平、公众参与等因素,差异化地制定滨海和内陆C2N发展战略,在此基础上进一步开展选址和确定建设时序。[结论]尽管面临诸多挑战,C2N能直接实现容量替代,减少煤电厂碳排放并显著降低核电建设成本;其应用在我国可有多种应用场景,能为东部沿海经济发达省份快速降碳提供一种思路;其推进需要与我国“双碳”整体推进、能源发展战略、原料供应安全和煤电机组退役统筹考虑,从沿海向内陆有序推进;其可行性将随着核电技术的发展特别是其固有安全性的提高而增强;其落地实施还需要政策的顶层设计支持,涉及国家经济发展和产业战略,调整周期较长;基于我国煤电规模和核电建设周期,其实施过程可能持续数十年。展开更多
利用常规研究方法,对甜菜单体附加系M 14品系(B eta vu lg aris L.,VV+1C、2n=18+1)的生殖方式进行细胞学与胚胎学研究.结果表明:(1)甜菜单体附加系M 14的4代细胞学检查表明:染色体组分别为VV+1C、2n=18+1;VV+0、2n=18+0;VV+2C、2n=18+2...利用常规研究方法,对甜菜单体附加系M 14品系(B eta vu lg aris L.,VV+1C、2n=18+1)的生殖方式进行细胞学与胚胎学研究.结果表明:(1)甜菜单体附加系M 14的4代细胞学检查表明:染色体组分别为VV+1C、2n=18+1;VV+0、2n=18+0;VV+2C、2n=18+2;VVV+0、2n=27+0;VVV+1C、2n=27+1;VVV+2C、2n=27+2等,其中VV+1C、2n=18+1的植株传递率平均为96.7%,表现为稳定传递,具有二倍体孢子无融合生殖特性;其余各种分离植株的传递率总计为3.25%,有性生殖发生率较低.(2)胚胎学研究表明,二倍体孢子无融合生殖的胚珠中,珠孔处看不到花粉管,胚囊没有发生受精作用.2个助细胞提前退化,半数卵细胞的极性与正常卵细胞相反;卵与次生核不经受精而自发分裂,卵细胞自发分裂产生无性胚,次生核自发分裂产生核型胚乳,而且次生核自发分裂早于卵细胞分裂;有性生殖胚珠中,珠孔处可见多条花粉管,胚囊里见到精卵融合的图像.表明甜菜单体附加系M 14是以二倍体孢子无融合生殖为主要繁殖方式,有性生殖为次要敏殖方式的兼性无融合生殖体.展开更多
The novel copper?complex with salicylaldehyde benzoylhydrazone and pyridine ligands, Cu(C14H10N2O2)(C5H5N), has been synthesized and characterized by elemental analysis, IR and thermal analysis. The crystal structure ...The novel copper?complex with salicylaldehyde benzoylhydrazone and pyridine ligands, Cu(C14H10N2O2)(C5H5N), has been synthesized and characterized by elemental analysis, IR and thermal analysis. The crystal structure of the title complex has been determined by single crystal X ray diffraction techniques. The crystal belongs to monoclinic with space group P21/c. The cell parameters are: a=1.6362(9)nm, b=1.7140(9)nm, c=1.2255(7)nm, β=105.168(9)°, V=3.317(3)nm3, Z=8, Dc=1.525g·cm-3, μ(MoKα)=1.334mm-1, F(000)=1560. The structure wasrefined to final R1=0.0376, wR2=0.0909. The copper?ion lies in a distorted square planar environment composed of two oxygen atoms, one nitrogen atom of tridentate acyhydrazone Schiff base ligand and one nitrogen atom of the pyridine ligand. CCDC: 193111.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11574167)
文摘Photocatalytic water splitting has gained increasing attention, since it utilizes renewable resources, such as water and solar energy, to produce hydrogen. Using the first-principles density functional theory, we investigate the properties of the single layer C_2N which was successfully synthesized. We reveal that monolayer C_2N has a substantial direct band gap of 2.45 eV. To regulate its band gap, four different nonmetal elements（B, O, P, and S） on the cation and anion sites are considered. Among them, B-doped N site is the most effective one, with the lowest formation energy and a band gap of 2.01 eV. P-doped N site is the next, with a band gap of 2.08 eV, though its formation energy is higher. The band alignments with respect to the water redox levels show that, for these two dopings, the thermodynamic criterion for the overall water splitting is satisfied. We therefore predict that B-or P-doped C_2N, with an appropriate band gap and an optimal band-edge position, would be a promising photocatalyst for visible-light water splitting.
文摘针对现有指挥控制网络(command and control network,C2N)初始负载大多为基于节点,缺少边初始负载定义,结合边重要性及边层级,提出兼顾边重要性和边层级的C2N边初始负载。给出边度和自我网络边介数定义;结合改进桥接系数、边度和自我网络边介数,提出边重要性新定义;接着给出边层级定义,结合边重要性和边层级,提出新的边初始负载定义;仿真分析了不同失效模型的抗毁性,结果表明该初始负载定义的级联失效模型具有更强的抗毁能力。
文摘[目的]煤炭在我国能源结构中长期占据主导地位。随着全球气候治理进程加速,全球主要经济体都朝着碳中和目标快速迈进。此外,近年来我国核电新核准以及在建的机组数量始终保持增长态势,在全球范围内位列第一,核电显著的减排效应使“煤电改核电”(Coal to Nuclear,C2N)有望成为新的传统能源替代场景。文章通过分析C2N的发展现状,对C2N的关键问题进行研究,探究C2N的典型场景,对C2N在我国的发展前景进行展望,旨在为未来我国大规模煤电厂转型发展利用提供新思路。[方法]采用文献综述和比较分析的研究方法,梳理了C2N的发展情况,分析了国内外在C2N技术和实践方面的最新进展;同时,结合相关核电行业政策法规文件和煤电、核电厂部分技术参数对比,探讨了C2N的关键问题和应用场景。[结果]研究表明C2N的发展在理论上可行,但必须与其他类型能源协同发展,共同服务于我国的能源发展战略。未来,需要基于现有研究,结合技术进步、我国中长期能源电力流向、区域经济发展水平、公众参与等因素,差异化地制定滨海和内陆C2N发展战略,在此基础上进一步开展选址和确定建设时序。[结论]尽管面临诸多挑战,C2N能直接实现容量替代,减少煤电厂碳排放并显著降低核电建设成本;其应用在我国可有多种应用场景,能为东部沿海经济发达省份快速降碳提供一种思路;其推进需要与我国“双碳”整体推进、能源发展战略、原料供应安全和煤电机组退役统筹考虑,从沿海向内陆有序推进;其可行性将随着核电技术的发展特别是其固有安全性的提高而增强;其落地实施还需要政策的顶层设计支持,涉及国家经济发展和产业战略,调整周期较长;基于我国煤电规模和核电建设周期,其实施过程可能持续数十年。
文摘利用常规研究方法,对甜菜单体附加系M 14品系(B eta vu lg aris L.,VV+1C、2n=18+1)的生殖方式进行细胞学与胚胎学研究.结果表明:(1)甜菜单体附加系M 14的4代细胞学检查表明:染色体组分别为VV+1C、2n=18+1;VV+0、2n=18+0;VV+2C、2n=18+2;VVV+0、2n=27+0;VVV+1C、2n=27+1;VVV+2C、2n=27+2等,其中VV+1C、2n=18+1的植株传递率平均为96.7%,表现为稳定传递,具有二倍体孢子无融合生殖特性;其余各种分离植株的传递率总计为3.25%,有性生殖发生率较低.(2)胚胎学研究表明,二倍体孢子无融合生殖的胚珠中,珠孔处看不到花粉管,胚囊没有发生受精作用.2个助细胞提前退化,半数卵细胞的极性与正常卵细胞相反;卵与次生核不经受精而自发分裂,卵细胞自发分裂产生无性胚,次生核自发分裂产生核型胚乳,而且次生核自发分裂早于卵细胞分裂;有性生殖胚珠中,珠孔处可见多条花粉管,胚囊里见到精卵融合的图像.表明甜菜单体附加系M 14是以二倍体孢子无融合生殖为主要繁殖方式,有性生殖为次要敏殖方式的兼性无融合生殖体.
文摘The novel copper?complex with salicylaldehyde benzoylhydrazone and pyridine ligands, Cu(C14H10N2O2)(C5H5N), has been synthesized and characterized by elemental analysis, IR and thermal analysis. The crystal structure of the title complex has been determined by single crystal X ray diffraction techniques. The crystal belongs to monoclinic with space group P21/c. The cell parameters are: a=1.6362(9)nm, b=1.7140(9)nm, c=1.2255(7)nm, β=105.168(9)°, V=3.317(3)nm3, Z=8, Dc=1.525g·cm-3, μ(MoKα)=1.334mm-1, F(000)=1560. The structure wasrefined to final R1=0.0376, wR2=0.0909. The copper?ion lies in a distorted square planar environment composed of two oxygen atoms, one nitrogen atom of tridentate acyhydrazone Schiff base ligand and one nitrogen atom of the pyridine ligand. CCDC: 193111.
