本文基于世界投入产出数据,借鉴并拓展Los et al(2015)和Timmer et al(2014)的方法,测度产品内国际分工的程度和要素收入份额,并构建一国在产品内国际分工中的相对地位指数。通过分析中国制造业产品内国际分工的发展趋势,得到结论:整体...本文基于世界投入产出数据,借鉴并拓展Los et al(2015)和Timmer et al(2014)的方法,测度产品内国际分工的程度和要素收入份额,并构建一国在产品内国际分工中的相对地位指数。通过分析中国制造业产品内国际分工的发展趋势,得到结论:整体来看,中国制造业产品内国际分工的程度在不断加深,要素结构在不断优化,中国在分工中的相对地位基本保持不变;分行业来看,中国大部分行业产品内国际分工的程度在增加,其中分工程度最深的是电子制造业且中国在电子制造业产品内国际分工中的相对地位呈现上升趋势。展开更多
In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDY...In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDYs increase as the number of halogen atoms increases.It is also found that the position of the valence band maximum(VBM)is influenced by the electronegativity of halogen atoms.The higher the electronegativity,the deeper the VBM of the GDYs modified by the same number of halogen atoms.Importantly,our results revealed that the bandgap of GDY could be effectively tuned by mixing types of halogen atoms.The new generated conduction band and valence band edges are properly aligned with the oxidation and reduction potentials of water.Further thermodynamic analysis confirms that some models with mixing types of halogen atoms exhibit higher performance of overall photocatalytic water splitting than non-mixing models.This work provides useful insights for designing efficient photocatalysts that can be used for overall water splitting.展开更多
It is shown in this article that by changing the initial operation condition of the batch processes, the dynamic performance of the system can be varied largely, especially for the initial operational temperature of t...It is shown in this article that by changing the initial operation condition of the batch processes, the dynamic performance of the system can be varied largely, especially for the initial operational temperature of the exothermic reaction. The initial operation condition is often ignored in the designing batch processes for flexibility against disturbances or parameter variations. When the initial condition is not rigid as in the case of a batch reactor, where the initial reaction temperature is quite arbitrary, optimization can also be applied to determine the ＂best＂ initial condition to use. Problems for dynamic flexibility analysis of exothermic reaction including initial temperature and process operation can be formulated as dynamic optimization problems. Formulations are derived when the initial conditions are considered or not. When the initial conditions are considered, the initial condition can be transferred into control variables in the first optimal step. The solution of the dynamic optimization is on the basis of Rugge-Kutta integration algorithm and decomposition search algorithm. This method, as illustrated and tested with two highly nonlinear process problems, enables the determination of the optimal level. The dynamic performance is improved by the proposed method in the two exothermic reaction examples.展开更多
To explore the problems of dynamic change in production demand and operating contradiction in production process, a new extension theory-based production operation method is proposed. The core is the demand requisitio...To explore the problems of dynamic change in production demand and operating contradiction in production process, a new extension theory-based production operation method is proposed. The core is the demand requisition, contradiction resolution and operation classification. For the demand requisition, the deep and comprehensive demand elements are collected by the conjugating analysis. For the contradiction resolution, the conflict between the demand and operating elements are solved by the extension reasoning, extension transformation and consistency judgment. For the operating classification, the operating importance among the operating elements is calculated by the extension clustering so as to guide the production operation and ensure the production safety. Through the actual application in the cascade reaction process of high-density polyethylene (HDPE) of a chemical plant, cases study and comparison show that the proposed extension theory-based production operation method is significantly better than the traditional experience-based operation method in actual production process, which exploits a new way to the research on the production operating methods for industrial process.展开更多
文摘本文基于世界投入产出数据,借鉴并拓展Los et al(2015)和Timmer et al(2014)的方法,测度产品内国际分工的程度和要素收入份额,并构建一国在产品内国际分工中的相对地位指数。通过分析中国制造业产品内国际分工的发展趋势,得到结论:整体来看,中国制造业产品内国际分工的程度在不断加深,要素结构在不断优化,中国在分工中的相对地位基本保持不变;分行业来看,中国大部分行业产品内国际分工的程度在增加,其中分工程度最深的是电子制造业且中国在电子制造业产品内国际分工中的相对地位呈现上升趋势。
基金funded by the National Natural Science Foundation of China(No.21973013 and No.21673040)the Natural Science Foundation of Fujian Province of China(No.2020J02025)“Chuying Program”for the Top Young Talents of Fujian Province。
文摘In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDYs increase as the number of halogen atoms increases.It is also found that the position of the valence band maximum(VBM)is influenced by the electronegativity of halogen atoms.The higher the electronegativity,the deeper the VBM of the GDYs modified by the same number of halogen atoms.Importantly,our results revealed that the bandgap of GDY could be effectively tuned by mixing types of halogen atoms.The new generated conduction band and valence band edges are properly aligned with the oxidation and reduction potentials of water.Further thermodynamic analysis confirms that some models with mixing types of halogen atoms exhibit higher performance of overall photocatalytic water splitting than non-mixing models.This work provides useful insights for designing efficient photocatalysts that can be used for overall water splitting.
基金Supported by the National Natural Science Foundation of China （20536020, 20876056）.
文摘It is shown in this article that by changing the initial operation condition of the batch processes, the dynamic performance of the system can be varied largely, especially for the initial operational temperature of the exothermic reaction. The initial operation condition is often ignored in the designing batch processes for flexibility against disturbances or parameter variations. When the initial condition is not rigid as in the case of a batch reactor, where the initial reaction temperature is quite arbitrary, optimization can also be applied to determine the ＂best＂ initial condition to use. Problems for dynamic flexibility analysis of exothermic reaction including initial temperature and process operation can be formulated as dynamic optimization problems. Formulations are derived when the initial conditions are considered or not. When the initial conditions are considered, the initial condition can be transferred into control variables in the first optimal step. The solution of the dynamic optimization is on the basis of Rugge-Kutta integration algorithm and decomposition search algorithm. This method, as illustrated and tested with two highly nonlinear process problems, enables the determination of the optimal level. The dynamic performance is improved by the proposed method in the two exothermic reaction examples.
基金Supported by the National Natural Science Foundation of China(61104131)the Fundamental Research Funds for Central Universities(ZY1111)
文摘To explore the problems of dynamic change in production demand and operating contradiction in production process, a new extension theory-based production operation method is proposed. The core is the demand requisition, contradiction resolution and operation classification. For the demand requisition, the deep and comprehensive demand elements are collected by the conjugating analysis. For the contradiction resolution, the conflict between the demand and operating elements are solved by the extension reasoning, extension transformation and consistency judgment. For the operating classification, the operating importance among the operating elements is calculated by the extension clustering so as to guide the production operation and ensure the production safety. Through the actual application in the cascade reaction process of high-density polyethylene (HDPE) of a chemical plant, cases study and comparison show that the proposed extension theory-based production operation method is significantly better than the traditional experience-based operation method in actual production process, which exploits a new way to the research on the production operating methods for industrial process.
