This paper reconstructs,based on American and Chinese primary sources,the visits of Chinese mathematicians Shiing-shen Chern陈省身(Chen Xingshen)and Hua Luogeng华罗庚(Loo-Keng Hua)4 to the Institute for Advanced Study...This paper reconstructs,based on American and Chinese primary sources,the visits of Chinese mathematicians Shiing-shen Chern陈省身(Chen Xingshen)and Hua Luogeng华罗庚(Loo-Keng Hua)4 to the Institute for Advanced Study in Princeton in the United States in the 1940s,especially their interactions with Oswald Veblen and Hermann Weyl,two leading mathematicians at the IAS.It argues that Chern’s and Hua’s motivations and choices in regard to their transnational movements between China and the US were more nuanced and multifaceted than what is presented in existing accounts,and that socio-political factors combined with professional-personal ones to shape their decisions.The paper further uses their experiences to demonstrate the importance of transnational scientific interactions for the development of science in China,the US,and elsewhere in the twentieth century.展开更多
The hollow spherical covalent organic frameworks(COFs)have a wide application prospect thanks to their special structures.However,the controllable synthesis of uniform and stable hollow COFs is still a challenge.We he...The hollow spherical covalent organic frameworks(COFs)have a wide application prospect thanks to their special structures.However,the controllable synthesis of uniform and stable hollow COFs is still a challenge.We herein propose a self-templated method for the preparation of hollow COFs through the Ostwald ripening mechanism under ambient conditions,which avoids most disadvantages of the commonly used hard-templating and soft-templating methods.A detailed time-dependent study reveals that the COFs are transformed from initial spheres to hollow spheres because of the inside-out Ostwald ripening process.The obtained hollow spherical COFs have high crystallinity,specific surface area(2,036 m^(2)·g^(−1)),stability,and single-batch yield.Thanks to unique hollow structure,clear through holes,and hydrophobic pore environment of the hollow spherical COFs,the obtained immobilized lipase(BCL@H-COF-OMe)exhibits higher thermostability,polar organic solvent tolerance,and reusability.The BCL@H-COF-OMe also shows higher catalytic performance than the lipase immobilized on non-hollow COF and free lipase in the kinetic resolution of secondary alcohols.This study provides a simple approach for the preparation of hollow spherical COFs,and will promote the valuable research of COFs in the field of biocatalysis.展开更多
Ultrathin nanostructures have attracted much attention in recent years due to their predictable novel properties and various potential applications. The improvement in synthetic skills has led to many successful synth...Ultrathin nanostructures have attracted much attention in recent years due to their predictable novel properties and various potential applications. The improvement in synthetic skills has led to many successful syntheses of nanostructures including zerodimensional (0D) nanoclusters, one-dimensional (1D) nanowires, two-dimensional (2D) nanosheets and other higher-level complex nanostructures, where cluster-assembly of primary nanocrystals is a common process. In this review, progress in ultrathin nanocrystals in the last decade and several important factors in the growth mechanisms are covered. By giving examples of cluster assembly from 1D to 3D nanostructures, the utility of cluster assembly in the synthesis of new materials has been demonstrated.展开更多
High quality perovskite films with large columnar grains are greatly desired for efficient perovskite solar cells. Here, low volatility N-methyl-2-pyrrolidone(NMP) was added in MAI/IPA solution in a two-step spin-coat...High quality perovskite films with large columnar grains are greatly desired for efficient perovskite solar cells. Here, low volatility N-methyl-2-pyrrolidone(NMP) was added in MAI/IPA solution in a two-step spin-coating method, which promoted the conversion of lead iodide to perovskite. The perovskite films were annealed by a closed-steam annealing method to prolong the recrystallization process of perovskite films assisted by the residual NMP. It leaded to high quality CH_3NH_3PbI_3 perovskite films with large columnar grains due to its enhancement of the Oswald ripening. The large grain perovskite film leaded to efficient carrier transformation and injection, and low recombination. The photovoltaic performance of the perovskite solar cells was improved significantly.展开更多
Given the robust plurivocality that has characterized literature in Brazil since its colonial inception,and the eminently(and explicitly)receptive stance that many of its modem authors have adopted,I have structured m...Given the robust plurivocality that has characterized literature in Brazil since its colonial inception,and the eminently(and explicitly)receptive stance that many of its modem authors have adopted,I have structured my argument to follow two intersecting paths.Firstly,Clarice Lispector’s notion of“writing by ear”serves as a foundation for a renewed history of Brazilian literature,framed as a history of active listening.Secondly,the hope is to offer a Luso-Afro-Amerindian-Brazilian contribution to Latin American criticism,turning the semantic range of terms related to edges,margins,and borders into a more explicit semiotics of corporeality and performativity revolving around the ears and sound,echoes and silence,more generally.展开更多
This essay seeks to articulate a detailed reading through two anatomical selections-the mouth and tongue-in Brazilian art from the end of the 1960s.The reading is part of a shift in the matrix of Oswald de Andrade’s...This essay seeks to articulate a detailed reading through two anatomical selections-the mouth and tongue-in Brazilian art from the end of the 1960s.The reading is part of a shift in the matrix of Oswald de Andrade’s“Anthropophagic Manifesto,”originally published in the Re vista de Antropofagia in 1928,whose interpretations spread in Brazil during the second half of the 20th century.This study mobilises elements of the manifesto and its resonance in the works of artists such as Anna Maria Maiolino,Lygia Pape,Paulo Bruscky,and Lenora de Barros.展开更多
文摘This paper reconstructs,based on American and Chinese primary sources,the visits of Chinese mathematicians Shiing-shen Chern陈省身(Chen Xingshen)and Hua Luogeng华罗庚(Loo-Keng Hua)4 to the Institute for Advanced Study in Princeton in the United States in the 1940s,especially their interactions with Oswald Veblen and Hermann Weyl,two leading mathematicians at the IAS.It argues that Chern’s and Hua’s motivations and choices in regard to their transnational movements between China and the US were more nuanced and multifaceted than what is presented in existing accounts,and that socio-political factors combined with professional-personal ones to shape their decisions.The paper further uses their experiences to demonstrate the importance of transnational scientific interactions for the development of science in China,the US,and elsewhere in the twentieth century.
基金This work was supported by the National Natural Science Foundation of China(Nos.22078081,21908040,21901058,and 22178083)the Natural Science Foundation of Hebei Province(Nos.B2020202021 and B2019202216)+2 种基金Key Research and Development Program of Hebei Province(No.20372802D)Open Project Funding of the State Key Laboratory of Biocatalysis and Enzyme Engineering(No.SKLBEE2020011)the Natural Science Foundation of Tianjin(No.20JCYBJC00530).
文摘The hollow spherical covalent organic frameworks(COFs)have a wide application prospect thanks to their special structures.However,the controllable synthesis of uniform and stable hollow COFs is still a challenge.We herein propose a self-templated method for the preparation of hollow COFs through the Ostwald ripening mechanism under ambient conditions,which avoids most disadvantages of the commonly used hard-templating and soft-templating methods.A detailed time-dependent study reveals that the COFs are transformed from initial spheres to hollow spheres because of the inside-out Ostwald ripening process.The obtained hollow spherical COFs have high crystallinity,specific surface area(2,036 m^(2)·g^(−1)),stability,and single-batch yield.Thanks to unique hollow structure,clear through holes,and hydrophobic pore environment of the hollow spherical COFs,the obtained immobilized lipase(BCL@H-COF-OMe)exhibits higher thermostability,polar organic solvent tolerance,and reusability.The BCL@H-COF-OMe also shows higher catalytic performance than the lipase immobilized on non-hollow COF and free lipase in the kinetic resolution of secondary alcohols.This study provides a simple approach for the preparation of hollow spherical COFs,and will promote the valuable research of COFs in the field of biocatalysis.
基金supported by the National Natural Science Foundation of China (91127040, 20921001)the National Basic Research Program of China (973 Program, 2011CB932402)
文摘Ultrathin nanostructures have attracted much attention in recent years due to their predictable novel properties and various potential applications. The improvement in synthetic skills has led to many successful syntheses of nanostructures including zerodimensional (0D) nanoclusters, one-dimensional (1D) nanowires, two-dimensional (2D) nanosheets and other higher-level complex nanostructures, where cluster-assembly of primary nanocrystals is a common process. In this review, progress in ultrathin nanocrystals in the last decade and several important factors in the growth mechanisms are covered. By giving examples of cluster assembly from 1D to 3D nanostructures, the utility of cluster assembly in the synthesis of new materials has been demonstrated.
基金financially supported by the National Natural Science Foundation of China(Grant No.21463002)Startup Funding of Distinguished Professorship of "1000 Talents Program"(31370086963030)+4 种基金Shenzhen Jiawei Photovoltaic Lighting Co.,Ltd.Tsinghua University Initiative Scientific Research Program(20161080165)Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2016D01C008)Opening Project of State Key laboratory of Crystal Material(No.KF1610)Scientific Research Program of the Higher Education Institution of Xinjiang(XJEDU2017M038)
文摘High quality perovskite films with large columnar grains are greatly desired for efficient perovskite solar cells. Here, low volatility N-methyl-2-pyrrolidone(NMP) was added in MAI/IPA solution in a two-step spin-coating method, which promoted the conversion of lead iodide to perovskite. The perovskite films were annealed by a closed-steam annealing method to prolong the recrystallization process of perovskite films assisted by the residual NMP. It leaded to high quality CH_3NH_3PbI_3 perovskite films with large columnar grains due to its enhancement of the Oswald ripening. The large grain perovskite film leaded to efficient carrier transformation and injection, and low recombination. The photovoltaic performance of the perovskite solar cells was improved significantly.
文摘Given the robust plurivocality that has characterized literature in Brazil since its colonial inception,and the eminently(and explicitly)receptive stance that many of its modem authors have adopted,I have structured my argument to follow two intersecting paths.Firstly,Clarice Lispector’s notion of“writing by ear”serves as a foundation for a renewed history of Brazilian literature,framed as a history of active listening.Secondly,the hope is to offer a Luso-Afro-Amerindian-Brazilian contribution to Latin American criticism,turning the semantic range of terms related to edges,margins,and borders into a more explicit semiotics of corporeality and performativity revolving around the ears and sound,echoes and silence,more generally.
文摘This essay seeks to articulate a detailed reading through two anatomical selections-the mouth and tongue-in Brazilian art from the end of the 1960s.The reading is part of a shift in the matrix of Oswald de Andrade’s“Anthropophagic Manifesto,”originally published in the Re vista de Antropofagia in 1928,whose interpretations spread in Brazil during the second half of the 20th century.This study mobilises elements of the manifesto and its resonance in the works of artists such as Anna Maria Maiolino,Lygia Pape,Paulo Bruscky,and Lenora de Barros.
