In our previous work, the reactive dividing wall column(RDWC) was proposed and proved to be effective for selective hydrogenation and separation of C3 stream. In the present paper, the dynamics and control of the prop...In our previous work, the reactive dividing wall column(RDWC) was proposed and proved to be effective for selective hydrogenation and separation of C3 stream. In the present paper, the dynamics and control of the proposed RDWC are investigated. Four control structures including composition and temperature controls are proposed. The feed forward controllers are employed in the four control strategies to shorten the dynamic response time, reduce the maximum deviations and offer an immediate adjustment. The control structures are compared by applying them into the RDWC system with 20% disturbances in both the feed flow rate and the feed compositions, and the results are discussed.展开更多
The two-dimensional(2D)C3 N has emerged as a material with promising applications in high performance device owing to its intrinsic bandgap and tunable electronic properties.Although there are several reports about th...The two-dimensional(2D)C3 N has emerged as a material with promising applications in high performance device owing to its intrinsic bandgap and tunable electronic properties.Although there are several reports about the bandgap tuning of C3 N via stacking or forming nanoribbon,bandgap modulation of bilayer C3 N nanoribbons(C3NNRS)with various edge structures is still far from well understood.Here,based on extensive first-principles calculations,we demonstrated the effective bandgap engineering of C3 N by cutting it into hydrogen passivated C3 NNRS and stacking them into bilayer heterostructures.It was found that armchair(AC)C3 NNRS with three types of edge structures are all semiconductors,while only zigzag(ZZ)C3NNRS with edges composed of both C and N atoms(ZZCN/CN)are semiconductors.The bandgaps of all semiconducting C3 NNRS are larger than that of C3 N nanosheet.More interestingly,AC-C3 NNRS with CN/CN edges(AC-CN/CN)possess direct bandgap while ZZ-CN/CN have indirect bandgap.Compared with the monolayer C3 NNR,the bandgaps of bilayer C3NNRS can be greatly modulated via different stacking orders and edge structures,varying from 0.43 eV for ZZ-CN/CN with AB’-stacking to 0.04 eV for AC-CN/CN with AA-stacking.Particularly,transition from direct to indirect bandgap was observed in the bilayer AC-CN/CN heterostructure with AA^stacking,and the indirect-to-direct transition was found in the bilayer ZZ-CN/CN with ABstacking.This work provides insights into the effective bandgap engineering of C3 N and offers a new opportunity for its applications in nano-electronics and optoelectronic devices.展开更多
基金Supported by the National Basic Research Program of China(2012CB720500)the National Supporting Research Program of China(2013BAA03B01)+1 种基金the National Natural Science Foundation of China(21176178)China Scholarship Council(CSC[2015]3022)
文摘In our previous work, the reactive dividing wall column(RDWC) was proposed and proved to be effective for selective hydrogenation and separation of C3 stream. In the present paper, the dynamics and control of the proposed RDWC are investigated. Four control structures including composition and temperature controls are proposed. The feed forward controllers are employed in the four control strategies to shorten the dynamic response time, reduce the maximum deviations and offer an immediate adjustment. The control structures are compared by applying them into the RDWC system with 20% disturbances in both the feed flow rate and the feed compositions, and the results are discussed.
基金This work was supported by the National Natural Science Foundation of China(Grant No.21673075).
文摘The two-dimensional(2D)C3 N has emerged as a material with promising applications in high performance device owing to its intrinsic bandgap and tunable electronic properties.Although there are several reports about the bandgap tuning of C3 N via stacking or forming nanoribbon,bandgap modulation of bilayer C3 N nanoribbons(C3NNRS)with various edge structures is still far from well understood.Here,based on extensive first-principles calculations,we demonstrated the effective bandgap engineering of C3 N by cutting it into hydrogen passivated C3 NNRS and stacking them into bilayer heterostructures.It was found that armchair(AC)C3 NNRS with three types of edge structures are all semiconductors,while only zigzag(ZZ)C3NNRS with edges composed of both C and N atoms(ZZCN/CN)are semiconductors.The bandgaps of all semiconducting C3 NNRS are larger than that of C3 N nanosheet.More interestingly,AC-C3 NNRS with CN/CN edges(AC-CN/CN)possess direct bandgap while ZZ-CN/CN have indirect bandgap.Compared with the monolayer C3 NNR,the bandgaps of bilayer C3NNRS can be greatly modulated via different stacking orders and edge structures,varying from 0.43 eV for ZZ-CN/CN with AB’-stacking to 0.04 eV for AC-CN/CN with AA-stacking.Particularly,transition from direct to indirect bandgap was observed in the bilayer AC-CN/CN heterostructure with AA^stacking,and the indirect-to-direct transition was found in the bilayer ZZ-CN/CN with ABstacking.This work provides insights into the effective bandgap engineering of C3 N and offers a new opportunity for its applications in nano-electronics and optoelectronic devices.
