The tensile cable-strut structure is a self-equilibrate pre-stressed system.The initial pre-stress cal- culation is the fundamental structural analysis.A new numerical procedure was developed.The force density method ...The tensile cable-strut structure is a self-equilibrate pre-stressed system.The initial pre-stress cal- culation is the fundamental structural analysis.A new numerical procedure was developed.The force density method is the cornerstone of analytical formula,and then introduced into linear adjustment theory;the least square least norm solution,the optimized initial pre-stress,is yielded.The initial pre-stress and structural performances of a particular single-layer saddle-shaped cable-net structure were analyzed with the developed method,which is proved to be efficient and correct.The modal analyses were performed with respect to various pre-stress levels.Finally,the structural performances were investigated comprehensively.展开更多
Bamboo shavings, the outer or intermediate layer of bamboo stems, are the bulk of by-products produced in bamboo processing. In this study we investigated the isolation, chemical characterization, and immunostimulator...Bamboo shavings, the outer or intermediate layer of bamboo stems, are the bulk of by-products produced in bamboo processing. In this study we investigated the isolation, chemical characterization, and immunostimulatory activity in vitro of the hemicelluloses from bamboo shavings. Shavings were first pretreated by steam explosion. The optimal pretreatment was found to be steam explosion at 2.2 MPa for 1 min. Following this pretreatment, the yield of hemicelluloses reached（2.05±0.22）%（based on the dry dewaxed raw materials）, which was 5.7-fold higher than that of untreated samples. Bamboo-shavings hemicellulose（BSH） was then prepared by hot water extraction and ethanol precipitation from the steam-exploded shavings. Purification of BSH by anion-exchange chromatography of diethylaminoethanol（DEAE）-sepharose Fast Flow resulted in a neutral fraction（BSH-1, purity of 95.3%, yield of 1.06%） and an acidic fraction（BSH-2, purity of 92.5%, yield of 0.79%）. The weight-average molecular weights（Mw） of BSH-1 and BSH-2 were 12 800 and 11 300 g/mol, respectively. Chemical and structural analyses by Fourier transform infrared spectroscopy（FT-IR）, 1D（^1H and ^13C） and 2D（heteronuclear single quantum correlation（HSQC）） nuclear magnetic resonance（NMR） spectra revealed that BSH-1 was O-acetylated-arabinoxylan and BSH-2 was O-acetylated-（4-Omethylglucurono）-arabinoxylan. BSH-1 had a higher content of acetyl groups than BSH-2. For the immunomodulatory activity in vitro, BSH and BSH-2 significantly stimulated mouse splenocyte proliferation while BSH-1 had no effect; BSH, BSH-1, and BSH-2 markedly enhanced the phagocytosis activity and nitric oxide production of the murine macrophage RAW264.7 in a dose-dependent manner. Our results suggest that the water-extractable hemicelluloses from steam-exploded bamboo shavings are naturally acetylated and have immunostimulatory activity.展开更多
With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges wit...With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges with rich hierarchical pores have been synthesized. Pores of the material contain three levels of length scales, including millimeter, micrometer and nanometer. The structure can be tuned by changing the freezing media, adjusting the stirring rate or adding functional additives. On the other hand, by direct freeze-drying of a graphene oxide/surfactant suspension, a porous framework with directionally aligned pores is prepared. The surfactant gives a better dispersion of graphene oxide sheets, resulting in a high specific surface area. Both of the obtained materials exhibit excellent absorption capacity and good compression performance, providing a broad range of possible applications, such as absorbents, storage media, and carriers.展开更多
Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and in...Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.展开更多
This article focuses on two English translations of Ji Yun＇s 纪昀 eigh- teenth-century collection of ＂stories of the strange,＂ Random Jottings at the Cottage of Close Scrutiny （Yuewei caotang biji 阅微草堂笔记）. ...This article focuses on two English translations of Ji Yun＇s 纪昀 eigh- teenth-century collection of ＂stories of the strange,＂ Random Jottings at the Cottage of Close Scrutiny （Yuewei caotang biji 阅微草堂笔记）. The translation done by Leo Tak-hung Chan is set within the context of his 1998 sinological monograph, while David Pollard＇s recent translation, published in 2014, stands as an edited volume of translation oriented toward the general reader. Referring to textual and paratextual elements in these two translations, I hope to show how the ＂setting＂ of a translation modulates its tone and message, which in turn unfolds with the selection, style and overall structure of the translation. I also draw from an actual dialog between Leo Chan and David Pollard, which evolves around the various aspects in translating Ji Yun＇s work and the more general issues in sinology and translating Chinese literature. The dialog between the two translators of Ji Yun further illustrates the translators＇ approaches to the original text, their mediating efforts toward crosscultural readability and literary felicity and specifically, how the state of mind of a translator might come into play with the ＂flavor＂ of a translation.展开更多
文摘The tensile cable-strut structure is a self-equilibrate pre-stressed system.The initial pre-stress cal- culation is the fundamental structural analysis.A new numerical procedure was developed.The force density method is the cornerstone of analytical formula,and then introduced into linear adjustment theory;the least square least norm solution,the optimized initial pre-stress,is yielded.The initial pre-stress and structural performances of a particular single-layer saddle-shaped cable-net structure were analyzed with the developed method,which is proved to be efficient and correct.The modal analyses were performed with respect to various pre-stress levels.Finally,the structural performances were investigated comprehensively.
基金Project supported by the National Key Technology R&D Program of China(No.2012BAK01B03)
文摘Bamboo shavings, the outer or intermediate layer of bamboo stems, are the bulk of by-products produced in bamboo processing. In this study we investigated the isolation, chemical characterization, and immunostimulatory activity in vitro of the hemicelluloses from bamboo shavings. Shavings were first pretreated by steam explosion. The optimal pretreatment was found to be steam explosion at 2.2 MPa for 1 min. Following this pretreatment, the yield of hemicelluloses reached（2.05±0.22）%（based on the dry dewaxed raw materials）, which was 5.7-fold higher than that of untreated samples. Bamboo-shavings hemicellulose（BSH） was then prepared by hot water extraction and ethanol precipitation from the steam-exploded shavings. Purification of BSH by anion-exchange chromatography of diethylaminoethanol（DEAE）-sepharose Fast Flow resulted in a neutral fraction（BSH-1, purity of 95.3%, yield of 1.06%） and an acidic fraction（BSH-2, purity of 92.5%, yield of 0.79%）. The weight-average molecular weights（Mw） of BSH-1 and BSH-2 were 12 800 and 11 300 g/mol, respectively. Chemical and structural analyses by Fourier transform infrared spectroscopy（FT-IR）, 1D（^1H and ^13C） and 2D（heteronuclear single quantum correlation（HSQC）） nuclear magnetic resonance（NMR） spectra revealed that BSH-1 was O-acetylated-arabinoxylan and BSH-2 was O-acetylated-（4-Omethylglucurono）-arabinoxylan. BSH-1 had a higher content of acetyl groups than BSH-2. For the immunomodulatory activity in vitro, BSH and BSH-2 significantly stimulated mouse splenocyte proliferation while BSH-1 had no effect; BSH, BSH-1, and BSH-2 markedly enhanced the phagocytosis activity and nitric oxide production of the murine macrophage RAW264.7 in a dose-dependent manner. Our results suggest that the water-extractable hemicelluloses from steam-exploded bamboo shavings are naturally acetylated and have immunostimulatory activity.
基金This work is supported by Beijing Natural Science Foundation （No. 2122027）, the National Basic Research Program of China （No. 2011CB013000）, the National Natural Science Foundation of China （No. 51372133）, and the Tsinghua University Initiative Scientific Research Program （No. 2012Z02102）.
文摘With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges with rich hierarchical pores have been synthesized. Pores of the material contain three levels of length scales, including millimeter, micrometer and nanometer. The structure can be tuned by changing the freezing media, adjusting the stirring rate or adding functional additives. On the other hand, by direct freeze-drying of a graphene oxide/surfactant suspension, a porous framework with directionally aligned pores is prepared. The surfactant gives a better dispersion of graphene oxide sheets, resulting in a high specific surface area. Both of the obtained materials exhibit excellent absorption capacity and good compression performance, providing a broad range of possible applications, such as absorbents, storage media, and carriers.
基金supported by the National Key R&D Program of China(2021YFB4001100)the National Natural Science Foundation of China(52025032,52103144,12032015,12121002,and 12172216)Science and Technology Innovation Action Plan of Shanghai(21190760100)。
文摘Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.
文摘This article focuses on two English translations of Ji Yun＇s 纪昀 eigh- teenth-century collection of ＂stories of the strange,＂ Random Jottings at the Cottage of Close Scrutiny （Yuewei caotang biji 阅微草堂笔记）. The translation done by Leo Tak-hung Chan is set within the context of his 1998 sinological monograph, while David Pollard＇s recent translation, published in 2014, stands as an edited volume of translation oriented toward the general reader. Referring to textual and paratextual elements in these two translations, I hope to show how the ＂setting＂ of a translation modulates its tone and message, which in turn unfolds with the selection, style and overall structure of the translation. I also draw from an actual dialog between Leo Chan and David Pollard, which evolves around the various aspects in translating Ji Yun＇s work and the more general issues in sinology and translating Chinese literature. The dialog between the two translators of Ji Yun further illustrates the translators＇ approaches to the original text, their mediating efforts toward crosscultural readability and literary felicity and specifically, how the state of mind of a translator might come into play with the ＂flavor＂ of a translation.
