The genus Hemerocallis is a kind of perennial herbaceous plants of Liliaceae and consists of about 15 species in the world,11 of which can be found in China. Some species of Hemerocallis are widely cultivated for medi...The genus Hemerocallis is a kind of perennial herbaceous plants of Liliaceae and consists of about 15 species in the world,11 of which can be found in China. Some species of Hemerocallis are widely cultivated for medicinal,edible and ornamental application. Considerable progress had been made in researches on chemical composition and functions of Hemerocallis plants. Previous phytochemical studies on Hemerocallis plants have demonstrated the presence of flavonoids,anthraquinones,alkaloids,terpenoids,triterpenes and triterpenoid saponins,caffeoylquinic acid derivatives,naphthalene glycosides,steroid and steroidal saponins,phenylethanoid glycosides,and lignans. Functional activities of Hemerocallis plants are mainly manifested in sedative hypnotic,antidepressant,antioxidant,anti-tumor,hepatoprotective,antibacterial and insecticidal activities. Chemical composition of Hemerocallis plants is various,and structural type is rich,and has a variety of significant functional activities,so it is worth further study.展开更多
The discovery of magnetic skyrmions provides a promising pathway for developing functional spintronic memory and logic devices. Towards the future high-density memory application, nanoscale skyrmions with miniaturized...The discovery of magnetic skyrmions provides a promising pathway for developing functional spintronic memory and logic devices. Towards the future high-density memory application, nanoscale skyrmions with miniaturized diameters, ideally down to 20 nm are required. Using x-ray magnetic circular dichroism transmission microscopy,nanoscale skyrmions are observed in the [Pt/Co/Ir]15 multilayer at room temperature. In particular, small skyrmions with minimum diameters approaching 20 nm could be generated by the current-induced spin-orbit torques. Through implementing material specific parameters, the dynamic process of skyrmion generation is further investigated by performing micromagnetic simulations. According to the simulation results, we find that both the tube-like Neel-type skyrmions and the bobber-like Neel-type skyrmions can be electrically generated. In particular, the size of the bobber-like Neel-type skyrmions can be effectively reduced by the spin-orbit torques,which leads to the formation of 20 nm Neel-type skyrmions. Our findings could be important for understanding the formation dynamics of nanoscale Neel-type spin textures, skyrmions and bobber in particular, which could also be useful for promoting nanoscale skyrmionic memories and logic devices.展开更多
基金Supported by Knowledge Innovation Program Funding of Institute of Food Science and Technology,Chinese Academy of Agricultural Sciences(125161015000150013)China Agriculture Research System(CARS-21)+1 种基金Science and Technology Project of Tibet Autonomous Region(Z2016B01N04)Beijing Food Crops Innovation Consortium(BAIC09-2017)
文摘The genus Hemerocallis is a kind of perennial herbaceous plants of Liliaceae and consists of about 15 species in the world,11 of which can be found in China. Some species of Hemerocallis are widely cultivated for medicinal,edible and ornamental application. Considerable progress had been made in researches on chemical composition and functions of Hemerocallis plants. Previous phytochemical studies on Hemerocallis plants have demonstrated the presence of flavonoids,anthraquinones,alkaloids,terpenoids,triterpenes and triterpenoid saponins,caffeoylquinic acid derivatives,naphthalene glycosides,steroid and steroidal saponins,phenylethanoid glycosides,and lignans. Functional activities of Hemerocallis plants are mainly manifested in sedative hypnotic,antidepressant,antioxidant,anti-tumor,hepatoprotective,antibacterial and insecticidal activities. Chemical composition of Hemerocallis plants is various,and structural type is rich,and has a variety of significant functional activities,so it is worth further study.
基金supported by the Basic Science Center Project of NSFC (Grant No. 51788104)the National Key R&D Program of China (Grant No. 2017YFA020620)+4 种基金the Beijing Natural Science Foundation (Grant No. Z190009)the National Key R&D Program of China (Grant No. 2018YFB1003304)the National Natural Science Foundation of China (Grant Nos. 11774194,51831005, 11861131008, 11804182, and 61832007)the Tsinghua University Initiative Scientific Research Program and the Beijing Advanced Innovation Center for Future Chip (ICFC) supported by U.S. Department of Energy (DE-AC02-05CH11231)by Lawrence Berkeley National Laboratory through the Laboratory Directed Research and Development (LDRD) Program。
文摘The discovery of magnetic skyrmions provides a promising pathway for developing functional spintronic memory and logic devices. Towards the future high-density memory application, nanoscale skyrmions with miniaturized diameters, ideally down to 20 nm are required. Using x-ray magnetic circular dichroism transmission microscopy,nanoscale skyrmions are observed in the [Pt/Co/Ir]15 multilayer at room temperature. In particular, small skyrmions with minimum diameters approaching 20 nm could be generated by the current-induced spin-orbit torques. Through implementing material specific parameters, the dynamic process of skyrmion generation is further investigated by performing micromagnetic simulations. According to the simulation results, we find that both the tube-like Neel-type skyrmions and the bobber-like Neel-type skyrmions can be electrically generated. In particular, the size of the bobber-like Neel-type skyrmions can be effectively reduced by the spin-orbit torques,which leads to the formation of 20 nm Neel-type skyrmions. Our findings could be important for understanding the formation dynamics of nanoscale Neel-type spin textures, skyrmions and bobber in particular, which could also be useful for promoting nanoscale skyrmionic memories and logic devices.
