二维Ag2S是一种具有间接宽带隙的半导体材料,由其在平面内和平面外具有独特的力学性质,因此受到了人们的广泛关注.本文基于密度泛函理论进行了第一性原理计算,研究了二维Ag2S的电子、光学性质的变化.二维Ag2S具有较强的方向各异性,通过...二维Ag2S是一种具有间接宽带隙的半导体材料,由其在平面内和平面外具有独特的力学性质,因此受到了人们的广泛关注.本文基于密度泛函理论进行了第一性原理计算,研究了二维Ag2S的电子、光学性质的变化.二维Ag2S具有较强的方向各异性,通过不同浓度的O取代S替换掺杂,发现随着O浓度的增加,带隙值出现先增大后减小的现象;由于O元素的引入,使二维Ag2S结构对称性降低,引起能带及光吸收、光反射的分布离散化.y方向4.56~5.36 e V处光吸收及光反射峰随掺杂浓度增加逐渐减小,且出现明显的蓝移.展开更多
Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedra...Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.展开更多
目的:为更有效防治棉花枯萎病和研制新型生物农药提供技术依据,本研究探究生防菌代谢产物与化学杀菌剂对棉花枯萎病菌(Fusarium oxysporum f. sp.vasinfectum)的抑制活性。方法:采用对峙培养法、菌丝生长速率法测定生防菌、发酵上清液...目的:为更有效防治棉花枯萎病和研制新型生物农药提供技术依据,本研究探究生防菌代谢产物与化学杀菌剂对棉花枯萎病菌(Fusarium oxysporum f. sp.vasinfectum)的抑制活性。方法:采用对峙培养法、菌丝生长速率法测定生防菌、发酵上清液、脂肽粗提物以及化学杀菌剂对棉花枯萎病菌的抑制特性。结果:对峙培养法得出生防菌SJ06对棉花枯萎病菌的抑制率为78.24%。发酵上清液的浓度从6.25μL/mL增至100.00μL/mL对病菌的抑制率从46.90%增至80.30%,其对病菌的EC50为7.37μL/mL;脂肽粗提物的质量浓度从673.96μg/mL增至8 120.00μg/mL对病菌的抑制率从19.90%增至77.30%,对病菌的EC50为2 720.20μg/mL。棉花枯萎病菌对多菌灵、戊唑醇的敏感性较高,戊唑醇和多菌灵对病菌的EC50分别为0.34、0.49μg/mL;其次分别为腈菌唑、苯醚甲环唑和丙环唑,其对病菌的EC50分别为1.07、1.34、1.54μg/mL,而丙森锌对病菌的抑制活性较差,EC50为63.25μg/mL。结论:解淀粉芽孢杆菌发酵代谢物和戊唑醇等麦角甾醇生物合成抑制剂对棉花枯萎病菌具有较好的抑制活性。展开更多
文摘二维Ag2S是一种具有间接宽带隙的半导体材料,由其在平面内和平面外具有独特的力学性质,因此受到了人们的广泛关注.本文基于密度泛函理论进行了第一性原理计算,研究了二维Ag2S的电子、光学性质的变化.二维Ag2S具有较强的方向各异性,通过不同浓度的O取代S替换掺杂,发现随着O浓度的增加,带隙值出现先增大后减小的现象;由于O元素的引入,使二维Ag2S结构对称性降低,引起能带及光吸收、光反射的分布离散化.y方向4.56~5.36 e V处光吸收及光反射峰随掺杂浓度增加逐渐减小,且出现明显的蓝移.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11864040,11964037,and 11664038)。
文摘Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.
