Lithium sulfur batteries(LSBs)show great promise as next-generation batteries due to their high energy density.However,commercialization is hindered by limited cycle life,fast capacity decay and poor sulfur utilizatio...Lithium sulfur batteries(LSBs)show great promise as next-generation batteries due to their high energy density.However,commercialization is hindered by limited cycle life,fast capacity decay and poor sulfur utilization,primarily due to the intricate phase evolution during battery operation and insulating characteristics of sulfur,leading to uncontrollable sulfur and polysulfide distribution and inefficient conversion kinetics.Therefore,the incorporation of metal and covalent organic frameworks(MOFs and COFs)has been widely employed in LSBs to serve as hosts,enabling the regulation of conversion and diffusion behavior of guest species,including lithium ions,sulfur and polysulfides,within their well-defined nanosized cavities.Nevertheless,pristine frameworks often fail to meet the requisite standards,and framework functionalization offers unique opportunities to tailor desired attributes and facilitate selective host-guest interactions in LSBs.However,a thorough understanding on how to precisely customize the nano-channels with functional groups to promote such interactions remains largely unexplored.In this review,we provide a systematic discussion on how the grafting of functional groups containing various active sites can play a role in host-guest chemistry,and focus on the latest advancements in engineering functionalized MOFs and COFs as charged-species regulators to tackle the problems causing poor LSB electrochemical performance.The concepts of electrophilic and nucleophilic effects are proposed,uncovering the mechanisms of framework functionalization in LSBs and serving as guidance for future developments.展开更多
Hydrogen spillover mechanism of metal-supported covalent-organic frameworks COF-105 is investigated by means of the density functional theory, and the effects of metal catalysts M_4（Pt_4, Pd_4, and Ni_4） on the whol...Hydrogen spillover mechanism of metal-supported covalent-organic frameworks COF-105 is investigated by means of the density functional theory, and the effects of metal catalysts M_4（Pt_4, Pd_4, and Ni_4） on the whole spillover process are systematically analyzed. These three metal catalysts exhibit several similar phenomena：（i） they prefer to deposit on the tetra（_4-dihydroxyborylphenyl） silane（TBPS） cluster with surface-contacted configuration;（ii） only the H atoms at the bridge site can migrate to 2,3,6,7,10,11-hexahydroxy triphenylene（HHTP） and TBPS surfaces, and the migration process is an endothermic reaction and not stable;（iii） the introduction of M_4 catalyst can greatly reduce the diffusion energy barrier of H atoms, which makes it easier for the H atoms to diffuse on the substrate surface. Differently, all of the H2 molecules spontaneously dissociate into H atoms onto Pt_4 and Pd_4clusters. However, the adsorbed H2 molecules on Ni_4 cluster show two types of adsorption states： one activated state with stretched H–H bond length of 0.88 ？A via the Kubas interaction and five dissociated states with separated hydrogen atoms. Among all the M_4 catalysts, the orders of the binding energy of M_4 deposited on the substrate and average chemisorption energy per H2 molecule are Pt_4〉Ni_4〉Pd_4. On the contrary, the orders of the migration and diffusion barriers of H atoms are Pt_4展开更多
This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (...This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (FL) and genetic algorithm (GA) framework were chosen as the best methodologies for design, optimization and control of crude oil distillation column. It was discovered that many past researchers used rigorous simulations which led to convergence problems that were time consuming. The use of dynamic mathematical models was also challenging as these models were also time dependent. The proposed methodologies use back-propagation algorithm to replace the convergence problem using error minimal method.展开更多
The paper firstly analyses disadvantages in the traditional Web database systems. And then it puts forward a simplified framework called database-oriented Web framework (DOWF). In this framework, the pages and the dat...The paper firstly analyses disadvantages in the traditional Web database systems. And then it puts forward a simplified framework called database-oriented Web framework (DOWF). In this framework, the pages and the data are all managed by database system. In order to get keywords or search a special page, which the users accessed before, users access the static pages by common script procedure (CSP), and access the dynamic pages by functional script procedure (FSP) and CSP. The article expounds the method how to implement DOWF in details. The paper also analyses the mechanism of a DOWF site by implementing a prototype system. At last, the article gives the features of DOWS in search, in security, in reuse of pages and in offline waiting, etc. Key words database-oriented - Web framework - common script procedure (CSP) - functional script procedure (FSP) CLC number TP 391 Foundation item: Supported by Natural Science Foundation of Jiangsu Province (BK2003030).Biography: ZHU Qiao-ming (1963-), male, professor, research direction: Web information processing chinses information processing.展开更多
基金supported by the Singapore Ministry of Education,and the National Research Foundation(NRF)for research conducted at the National University of Singapore(CRP NRF-CRP26-2021-0003).
文摘Lithium sulfur batteries(LSBs)show great promise as next-generation batteries due to their high energy density.However,commercialization is hindered by limited cycle life,fast capacity decay and poor sulfur utilization,primarily due to the intricate phase evolution during battery operation and insulating characteristics of sulfur,leading to uncontrollable sulfur and polysulfide distribution and inefficient conversion kinetics.Therefore,the incorporation of metal and covalent organic frameworks(MOFs and COFs)has been widely employed in LSBs to serve as hosts,enabling the regulation of conversion and diffusion behavior of guest species,including lithium ions,sulfur and polysulfides,within their well-defined nanosized cavities.Nevertheless,pristine frameworks often fail to meet the requisite standards,and framework functionalization offers unique opportunities to tailor desired attributes and facilitate selective host-guest interactions in LSBs.However,a thorough understanding on how to precisely customize the nano-channels with functional groups to promote such interactions remains largely unexplored.In this review,we provide a systematic discussion on how the grafting of functional groups containing various active sites can play a role in host-guest chemistry,and focus on the latest advancements in engineering functionalized MOFs and COFs as charged-species regulators to tackle the problems causing poor LSB electrochemical performance.The concepts of electrophilic and nucleophilic effects are proposed,uncovering the mechanisms of framework functionalization in LSBs and serving as guidance for future developments.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304079,11304140,11404094,and 11504088)the China National Scholarship Foundation(Grant No.201508410255)+4 种基金the Foundation for Young Core Teachers of Higher Education Institutions of Henan Province of Chinathe Foundation for Young Core Teachers of Henan University of Technology in Chinathe Korea Institute of Science and Technology(KIST)Institutional Program(Grant No.2E26291)Flag Program(Grant No.2E26300)the Research Grants of NRF funded by the National Research Foundation under the Ministry of Science,ICT&Future,Korea(Grant No.NRF-2015H1D3A1036078)
文摘Hydrogen spillover mechanism of metal-supported covalent-organic frameworks COF-105 is investigated by means of the density functional theory, and the effects of metal catalysts M_4（Pt_4, Pd_4, and Ni_4） on the whole spillover process are systematically analyzed. These three metal catalysts exhibit several similar phenomena：（i） they prefer to deposit on the tetra（_4-dihydroxyborylphenyl） silane（TBPS） cluster with surface-contacted configuration;（ii） only the H atoms at the bridge site can migrate to 2,3,6,7,10,11-hexahydroxy triphenylene（HHTP） and TBPS surfaces, and the migration process is an endothermic reaction and not stable;（iii） the introduction of M_4 catalyst can greatly reduce the diffusion energy barrier of H atoms, which makes it easier for the H atoms to diffuse on the substrate surface. Differently, all of the H2 molecules spontaneously dissociate into H atoms onto Pt_4 and Pd_4clusters. However, the adsorbed H2 molecules on Ni_4 cluster show two types of adsorption states： one activated state with stretched H–H bond length of 0.88 ？A via the Kubas interaction and five dissociated states with separated hydrogen atoms. Among all the M_4 catalysts, the orders of the binding energy of M_4 deposited on the substrate and average chemisorption energy per H2 molecule are Pt_4〉Ni_4〉Pd_4. On the contrary, the orders of the migration and diffusion barriers of H atoms are Pt_4
文摘This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (FL) and genetic algorithm (GA) framework were chosen as the best methodologies for design, optimization and control of crude oil distillation column. It was discovered that many past researchers used rigorous simulations which led to convergence problems that were time consuming. The use of dynamic mathematical models was also challenging as these models were also time dependent. The proposed methodologies use back-propagation algorithm to replace the convergence problem using error minimal method.
文摘The paper firstly analyses disadvantages in the traditional Web database systems. And then it puts forward a simplified framework called database-oriented Web framework (DOWF). In this framework, the pages and the data are all managed by database system. In order to get keywords or search a special page, which the users accessed before, users access the static pages by common script procedure (CSP), and access the dynamic pages by functional script procedure (FSP) and CSP. The article expounds the method how to implement DOWF in details. The paper also analyses the mechanism of a DOWF site by implementing a prototype system. At last, the article gives the features of DOWS in search, in security, in reuse of pages and in offline waiting, etc. Key words database-oriented - Web framework - common script procedure (CSP) - functional script procedure (FSP) CLC number TP 391 Foundation item: Supported by Natural Science Foundation of Jiangsu Province (BK2003030).Biography: ZHU Qiao-ming (1963-), male, professor, research direction: Web information processing chinses information processing.
