Having argued the importance of China's sustainable development in global sustainability, the authors review the achievements of China in sustainable development, especially its institutional construction. Environ...Having argued the importance of China's sustainable development in global sustainability, the authors review the achievements of China in sustainable development, especially its institutional construction. Environment to be counted in official's political performance rating system is thought of as a new institutional mechanism in China facilitating its sustainable development and then global sustainability. Then its significance is narrated and visions in future are envisioned. In the end, certain concrete suggestions for the rating system are given in a practical way.展开更多
The effect of mechanical strength of the dispersed particle gel(DPG)on its macro plugging performance is significant,however,little study has been reported.In this paper,DPG particles with different mechanical strengt...The effect of mechanical strength of the dispersed particle gel(DPG)on its macro plugging performance is significant,however,little study has been reported.In this paper,DPG particles with different mechanical strengths were obtained by mechanical shearing of bulk gels prepared with different formula.Young’s moduli of DPG particles on the micro and nano scales were measured by atomic force microscope for the first time.The mapping relationship among the formula of bulk gel,the Young’s moduli of the DPG particles and the final plugging performance were established.The results showed that when the Young’s moduli of the DPG particles increased from 82 to 328 Pa,the plugging rate increased significantly from 91.46%to 97.10%due to the distinctly enhanced stacking density and strength at this range.While when the Young’s moduli of the DPG particles surpassed 328 Pa,the further increase of plugging rate with the Young’s moduli of the DPG particles became insignificant.These results indicated that the improvement of plugging rate was more efficient by adjusting the Young’s moduli of the DPG particles within certain ranges,providing guidance for improving the macroscopic application properties of DPG systems in reservoir heterogeneity regulation.展开更多
Auxetic structures are a special class of structural components that exhibit a negative Poisson’s ratio(NPR)because of their constituent materials,internal microstructure,or structural geometry.To realize such struct...Auxetic structures are a special class of structural components that exhibit a negative Poisson’s ratio(NPR)because of their constituent materials,internal microstructure,or structural geometry.To realize such structures,specialized manufacturing processes are required to achieve a dimensional accuracy,reduction of material wastage,and a quicker fabrication.Hence,additive manufacturing(AM)techniques play a pivotal role in this context.AM is a layer-wise manufacturing process and builds the structure as per the designed geometry with appreciable precision and accuracy.Hence,it is extremely beneficial to fabricate auxetic structures using AM,which is otherwise a tedious and expensive task.In this study,a detailed discussion of the various AM techniques used in the fabrication of auxetic structures is presented.The advancements and advantages put forward by the AM domain have offered a plethora of opportunities for the fabrication and development of unconventional structures.Therefore,the authors have attempted to provide a meaningful encapsulation and a detailed discussion of the most recent of such advancements pertaining to auxetic structures.The article opens with a brief history of the growth of auxetic materials and later auxetic structures.Subsequently,discussions centering on the different AM techniques employed for the realization of auxetic structures are conducted.The basic principle,advantages,and disadvantages of these processes are discussed to provide an in-depth understanding of the current level of research.Furthermore,the performance of some of the prominent auxetic structures realized through these methods is discussed to compare their benefits and shortcomings.In addition,the influences of geometric and process parameters on such structures are evaluated through a comprehensive review to assess their feasibility for the later-mentioned applications.Finally,valuable insights into the applications,limitations,and prospects of AM for auxetic structures are provided to enable the readers to gauge the vitality of such manufacturing as a production method.展开更多
文摘Having argued the importance of China's sustainable development in global sustainability, the authors review the achievements of China in sustainable development, especially its institutional construction. Environment to be counted in official's political performance rating system is thought of as a new institutional mechanism in China facilitating its sustainable development and then global sustainability. Then its significance is narrated and visions in future are envisioned. In the end, certain concrete suggestions for the rating system are given in a practical way.
基金financially supported by the National Key Research and Development Program of China(No.2019YFA0708700)National Natural Science Foundation of China(52174054,51804326)Shandong Provincial Natural Science Foundation(ZR2019BEE046)
文摘The effect of mechanical strength of the dispersed particle gel(DPG)on its macro plugging performance is significant,however,little study has been reported.In this paper,DPG particles with different mechanical strengths were obtained by mechanical shearing of bulk gels prepared with different formula.Young’s moduli of DPG particles on the micro and nano scales were measured by atomic force microscope for the first time.The mapping relationship among the formula of bulk gel,the Young’s moduli of the DPG particles and the final plugging performance were established.The results showed that when the Young’s moduli of the DPG particles increased from 82 to 328 Pa,the plugging rate increased significantly from 91.46%to 97.10%due to the distinctly enhanced stacking density and strength at this range.While when the Young’s moduli of the DPG particles surpassed 328 Pa,the further increase of plugging rate with the Young’s moduli of the DPG particles became insignificant.These results indicated that the improvement of plugging rate was more efficient by adjusting the Young’s moduli of the DPG particles within certain ranges,providing guidance for improving the macroscopic application properties of DPG systems in reservoir heterogeneity regulation.
文摘Auxetic structures are a special class of structural components that exhibit a negative Poisson’s ratio(NPR)because of their constituent materials,internal microstructure,or structural geometry.To realize such structures,specialized manufacturing processes are required to achieve a dimensional accuracy,reduction of material wastage,and a quicker fabrication.Hence,additive manufacturing(AM)techniques play a pivotal role in this context.AM is a layer-wise manufacturing process and builds the structure as per the designed geometry with appreciable precision and accuracy.Hence,it is extremely beneficial to fabricate auxetic structures using AM,which is otherwise a tedious and expensive task.In this study,a detailed discussion of the various AM techniques used in the fabrication of auxetic structures is presented.The advancements and advantages put forward by the AM domain have offered a plethora of opportunities for the fabrication and development of unconventional structures.Therefore,the authors have attempted to provide a meaningful encapsulation and a detailed discussion of the most recent of such advancements pertaining to auxetic structures.The article opens with a brief history of the growth of auxetic materials and later auxetic structures.Subsequently,discussions centering on the different AM techniques employed for the realization of auxetic structures are conducted.The basic principle,advantages,and disadvantages of these processes are discussed to provide an in-depth understanding of the current level of research.Furthermore,the performance of some of the prominent auxetic structures realized through these methods is discussed to compare their benefits and shortcomings.In addition,the influences of geometric and process parameters on such structures are evaluated through a comprehensive review to assess their feasibility for the later-mentioned applications.Finally,valuable insights into the applications,limitations,and prospects of AM for auxetic structures are provided to enable the readers to gauge the vitality of such manufacturing as a production method.
