Hydraulic structures such as groin, longitudinal dike and seawall are common in water conservancy and water transportation engineering projects at home and abroad, which have long been dominated by solid mass structur...Hydraulic structures such as groin, longitudinal dike and seawall are common in water conservancy and water transportation engineering projects at home and abroad, which have long been dominated by solid mass structural form. With brush and stone as building materials, this kind of structure has an obvious engineering effect. However, it not only requires huge capital investments, but also has negative impacts on the ecological environment. The suspended flexible dam is an innovative engineering measure, and few theoretical and experimental researches of this type dam can be found at present. This paper studies the mechanism and shape characteristics of this dam and obtains the dynamic equilibrium equation of flexible dam, the float buoyancy expression, and the condition for transformation among three forms of the underwater shape of the dam. The results are valuable in engineering application and can be used as the reference for the future work due to the distinctive design philosophy, the small negative effects on environment and the consistency for sustainable development.展开更多
Telomerase is a unique ribonucleoprotein complex that protects chromosomes from degradation and recombination. The defects in telomerase activity eansed by the mutations in telomerase RNA （hTER） is associated with s...Telomerase is a unique ribonucleoprotein complex that protects chromosomes from degradation and recombination. The defects in telomerase activity eansed by the mutations in telomerase RNA （hTER） is associated with several human genetic diseases, so the molecular biology and structural biology of hTER are of great significance for the treatment of related diseases and the development of corresponding drugs. In this study, hTER was obtained by in vitro transcription, and then modified with N-methylisatoic anhydride （NMIA） by SHAPE （selective 2＇-hydroxyl aeylation analyzed by primer extension） ; finally, the eDNA fragment was obtained by reverse transcription to analyze the free nucleotides and dynamic structure of hTER, which may provide experimental basis for analyzing three--di- mensional structure of hTER obtained in vitro. In addition, the SHAPE parameters for long RNA fragment （ 〉 300 nt） were optimized. The results showed that 1 μmol/L hTER and 3.9 mmol/L NMIA were optimal, and 49 ℃ was the best temperature for primer extension.展开更多
The deployable structures based on shape memory polymer com-posites(SMPCs)have been developed for its unique properties,such as high reliability,low-cost,lightweight,and self-deployment without complex mechanical devi...The deployable structures based on shape memory polymer com-posites(SMPCs)have been developed for its unique properties,such as high reliability,low-cost,lightweight,and self-deployment without complex mechanical devices compared with traditional deployable structures.In order to increase the inflatable structure system’s robustness and light the weight of it,a cubic deployable support structure based on SMPC is designed and analyzed pre-liminarily.The cubic deployable support structure based on SMPC consists of four dependent spatial cages,each spatial cage is composed of 12 three-longeron SMPC truss booms and end con-nections.The shape recovery of arc-shaped deployable laminates drive the three-longeron SMPC truss booms to unfold,thus realize the expansion of the deployable support structure.The concept and operation of the cubic deployable support structure are described in detail.A series of experiments are performed on the three-longeron deployable laminates unit and the simplified cubic deployable support structure to investigate the shape recovery behavior in the deployment process.Results indicate that the cubic deployable support structure has a high deployment-tgo-stowage volume ratio and can achieve self-deployment,package,and deploy without complex mechanical devices.展开更多
文摘Hydraulic structures such as groin, longitudinal dike and seawall are common in water conservancy and water transportation engineering projects at home and abroad, which have long been dominated by solid mass structural form. With brush and stone as building materials, this kind of structure has an obvious engineering effect. However, it not only requires huge capital investments, but also has negative impacts on the ecological environment. The suspended flexible dam is an innovative engineering measure, and few theoretical and experimental researches of this type dam can be found at present. This paper studies the mechanism and shape characteristics of this dam and obtains the dynamic equilibrium equation of flexible dam, the float buoyancy expression, and the condition for transformation among three forms of the underwater shape of the dam. The results are valuable in engineering application and can be used as the reference for the future work due to the distinctive design philosophy, the small negative effects on environment and the consistency for sustainable development.
文摘Telomerase is a unique ribonucleoprotein complex that protects chromosomes from degradation and recombination. The defects in telomerase activity eansed by the mutations in telomerase RNA （hTER） is associated with several human genetic diseases, so the molecular biology and structural biology of hTER are of great significance for the treatment of related diseases and the development of corresponding drugs. In this study, hTER was obtained by in vitro transcription, and then modified with N-methylisatoic anhydride （NMIA） by SHAPE （selective 2＇-hydroxyl aeylation analyzed by primer extension） ; finally, the eDNA fragment was obtained by reverse transcription to analyze the free nucleotides and dynamic structure of hTER, which may provide experimental basis for analyzing three--di- mensional structure of hTER obtained in vitro. In addition, the SHAPE parameters for long RNA fragment （ 〉 300 nt） were optimized. The results showed that 1 μmol/L hTER and 3.9 mmol/L NMIA were optimal, and 49 ℃ was the best temperature for primer extension.
基金This work is supported by the National Natural Science Foundation of China(Grant No.11225211,No.11272106,No.11102052).
文摘The deployable structures based on shape memory polymer com-posites(SMPCs)have been developed for its unique properties,such as high reliability,low-cost,lightweight,and self-deployment without complex mechanical devices compared with traditional deployable structures.In order to increase the inflatable structure system’s robustness and light the weight of it,a cubic deployable support structure based on SMPC is designed and analyzed pre-liminarily.The cubic deployable support structure based on SMPC consists of four dependent spatial cages,each spatial cage is composed of 12 three-longeron SMPC truss booms and end con-nections.The shape recovery of arc-shaped deployable laminates drive the three-longeron SMPC truss booms to unfold,thus realize the expansion of the deployable support structure.The concept and operation of the cubic deployable support structure are described in detail.A series of experiments are performed on the three-longeron deployable laminates unit and the simplified cubic deployable support structure to investigate the shape recovery behavior in the deployment process.Results indicate that the cubic deployable support structure has a high deployment-tgo-stowage volume ratio and can achieve self-deployment,package,and deploy without complex mechanical devices.
