The leading character, Alexandra Bergson, in Willa Cather＇s O, Pioneer! has aroused much discussion concerning her sexual orientation. By looking at how this character grows from a woman suffering from sexual ambigui...The leading character, Alexandra Bergson, in Willa Cather＇s O, Pioneer! has aroused much discussion concerning her sexual orientation. By looking at how this character grows from a woman suffering from sexual ambiguity to one who achieves an composite of masculinity and femininity, this essay means to prove that although the writer＇s lesbianism influences her characterization to a certain degree, by endowing her characters with androgyny, Cather always attempts to create a group of characters who are striving for human beings wholeness.展开更多
The surface of nanocrystals plays a dominant role in many of their physical and chemical properties.However,controllability and tunability of nanocrystal surfaces remain unsolved.Herein,we report that the surface chem...The surface of nanocrystals plays a dominant role in many of their physical and chemical properties.However,controllability and tunability of nanocrystal surfaces remain unsolved.Herein,we report that the surface chemistry of nanocrystals,such as near-infrared Ag_(2)Se quantum dots(QDs),is sizedependent and composition-tunable.The Ag_(2)Se QDs tend to form a stable metal complex on the surface to minimize the surface energy,and therefore the surface chemistry can be varied with particle size.Meanwhile,changes in surface inorganic composition lead to reorganization of the surface ligands,and the surface chemistry also varies with composition.Therefore,the surface chemistry of Ag_(2)Se QDs,responsible for the photoluminescence(PL)quantum yield and photostability,can be tuned by changing their size or composition.Accordingly,we demonstrate that the PL intensity of the Ag_(2)Se QDs can be tuned reversely by adjusting the degree of surface Ag^(+) enrichment via light irradiation or the addition of AgNO_(3).This work provides insight into the control of QD surface for desired PL properties.展开更多
文摘The leading character, Alexandra Bergson, in Willa Cather＇s O, Pioneer! has aroused much discussion concerning her sexual orientation. By looking at how this character grows from a woman suffering from sexual ambiguity to one who achieves an composite of masculinity and femininity, this essay means to prove that although the writer＇s lesbianism influences her characterization to a certain degree, by endowing her characters with androgyny, Cather always attempts to create a group of characters who are striving for human beings wholeness.
基金supported by the National Natural Science Foundation of China(91859123)the National Key R&D Program of China(2019YFA0210103)。
文摘The surface of nanocrystals plays a dominant role in many of their physical and chemical properties.However,controllability and tunability of nanocrystal surfaces remain unsolved.Herein,we report that the surface chemistry of nanocrystals,such as near-infrared Ag_(2)Se quantum dots(QDs),is sizedependent and composition-tunable.The Ag_(2)Se QDs tend to form a stable metal complex on the surface to minimize the surface energy,and therefore the surface chemistry can be varied with particle size.Meanwhile,changes in surface inorganic composition lead to reorganization of the surface ligands,and the surface chemistry also varies with composition.Therefore,the surface chemistry of Ag_(2)Se QDs,responsible for the photoluminescence(PL)quantum yield and photostability,can be tuned by changing their size or composition.Accordingly,we demonstrate that the PL intensity of the Ag_(2)Se QDs can be tuned reversely by adjusting the degree of surface Ag^(+) enrichment via light irradiation or the addition of AgNO_(3).This work provides insight into the control of QD surface for desired PL properties.
