Based on the boron-containing thermally activated delayed fuorescence(TADF)compound p-AC(AC:acridine)5,9-dioxa-13 b-boranaphtho[3,2,1-de]anthracene(a),a series of new TADF molecules b1-b4 were designed via adding two ...Based on the boron-containing thermally activated delayed fuorescence(TADF)compound p-AC(AC:acridine)5,9-dioxa-13 b-boranaphtho[3,2,1-de]anthracene(a),a series of new TADF molecules b1-b4 were designed via adding two nitrogen atoms at the AC donor part.Density functional theory and time-dependent density functional theory calculations were performed on the frontier orbital energy levels,emission spectra,singlet-triplet states energy gaps(?EST),reverse intersystem crossing(RISC)rate constant(kRISC)for compounds a and b1-b4.Our calculation results show that the maximum emission wavelengths of b1-b4 are significantly blue-shifted by47-125 nm compared with that of a.Molecules b1 and b3 exhibit dark-blue emission,while molecules b2 and b4 display light-blue emission,indicating that these four derivatives could be potential organic light-emitting diode(OLED)candidates with blue-light emitting.Moreover,we found the RISC processes in a,b2,and b4 can occur not only from T_(1) state to S_(1) state,but also from T_(2) state to S_(1) state significantly,while the RISC processes in b1 and b3 mainly take place via the T_(2)→S_(1) hot exciton way.Importantly,the T_(1)→S_(1) kRISC values of b2 and b4 are predicted to be two to three times of that of a,indicating enhanced TADF property.Our results not only provide two promising boron-based TADF candidates(b2 and b4),but also offer useful theoretical basis for the design of blue OLED materials.展开更多
In 1984, Isaacs proposed the theories of Bπ-character and Iπ-character in π-separated group. This paper gives some new extension conditions of Iπ characters.
This paper is concerned with the issue of stabilization for the linear neutral systems with mixed delays. The attention is focused on the design of output feedback controllers which guarantee the asymptotical stabilit...This paper is concerned with the issue of stabilization for the linear neutral systems with mixed delays. The attention is focused on the design of output feedback controllers which guarantee the asymptotical stability of the closed-loop systems. Based on the model transformation of neutral type, the Lyapunov-Krasovskii functional method is employed to establish the delay-dependent stability criterion. Then, through the controller parameterization and some matrix transformation techniques, the desired parameters are determined under the delay-dependent design condition in terms of linear matrix inequalities (LMIs), and the desired controller is explicitly formulated. A numerical example is given to illustrate the effectiveness of the proposed method.展开更多
The financial crisis in late 2008 arrested economic development in the construction sector in the Middle East, with the result that investors＇ confidence in the sector is severely depressed. Delays constitute one of ...The financial crisis in late 2008 arrested economic development in the construction sector in the Middle East, with the result that investors＇ confidence in the sector is severely depressed. Delays constitute one of the highest impediments to project success. In this respect, the traditional management is no longer sufficient for construction project success. The objective of this study is to conduct a literature review to identify additional effective measures for controlling the potential delays risks in construction projects in order to maximize the opportunities for success in those projects. Thirty-six scholarly articles published between 2000 and 2011 are reviewed to identify related MDRC （measures for delays risks control）. This survey reveals that 60% of the studies are related to decision-making, performance, risk management variations and poor management knowledge of stakeholders and that 20% of these studies are undertaken in the Middle East. A further 25% of the studies are related to the lack of financial risk by stakeholders, and of these 14% are in the Middle East. A knowledge gap is identified in terms of project performance, stakeholder management and risk management, which are seen as significant measures of success in controlling project delay.展开更多
The design problem of delay-dependent robust control for uncertain discrete singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm-bounded. By establishing a finite ...The design problem of delay-dependent robust control for uncertain discrete singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm-bounded. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent robust stability condition is derived and expressed in terms of linear matrix inequalities (LMIs). A suitable robust state feedback control law is presented, which guarantees that the resultant closed-loop system is regular, causal and stable for all admissible uncertainties. Numerical examples are given to demonstrate the applicability of the proposed method.展开更多
In recent years,our country entered the stage of population aging, and this trend continues to increase. Young population declining dependency ratios and the elderly support ratio is growing.Many phenomena are heralds...In recent years,our country entered the stage of population aging, and this trend continues to increase. Young population declining dependency ratios and the elderly support ratio is growing.Many phenomena are heralds the retirement policy must introduce.At the same time, the adjustment of the legal retirement age for women, is also a concern hot spot and a topic of heated academia discussion in politics. As the extension of life expectancy, especially women to longer life expectancy and the education of the extension of women＇s status, ability to work has been greatly improved. Based on the change of various factors, delay retirement age for women in China＇s reform is imperative. This paper studies from the perspective of social justice, to the reform of the current situation of the development in our country and foreign experience to research the method of combining the draw delay retirement outstanding aspects of influence on female workers. From a personal health, family factors, career, personal value Suggestions such as, in order to Perfect delay enterprise female worker retirement age policy scheme and implement supporting measures.展开更多
基金supported by the National Natural Science Foundation of China(No.22173008)。
文摘Based on the boron-containing thermally activated delayed fuorescence(TADF)compound p-AC(AC:acridine)5,9-dioxa-13 b-boranaphtho[3,2,1-de]anthracene(a),a series of new TADF molecules b1-b4 were designed via adding two nitrogen atoms at the AC donor part.Density functional theory and time-dependent density functional theory calculations were performed on the frontier orbital energy levels,emission spectra,singlet-triplet states energy gaps(?EST),reverse intersystem crossing(RISC)rate constant(kRISC)for compounds a and b1-b4.Our calculation results show that the maximum emission wavelengths of b1-b4 are significantly blue-shifted by47-125 nm compared with that of a.Molecules b1 and b3 exhibit dark-blue emission,while molecules b2 and b4 display light-blue emission,indicating that these four derivatives could be potential organic light-emitting diode(OLED)candidates with blue-light emitting.Moreover,we found the RISC processes in a,b2,and b4 can occur not only from T_(1) state to S_(1) state,but also from T_(2) state to S_(1) state significantly,while the RISC processes in b1 and b3 mainly take place via the T_(2)→S_(1) hot exciton way.Importantly,the T_(1)→S_(1) kRISC values of b2 and b4 are predicted to be two to three times of that of a,indicating enhanced TADF property.Our results not only provide two promising boron-based TADF candidates(b2 and b4),but also offer useful theoretical basis for the design of blue OLED materials.
基金Supported by the Education Hall Foundation of Zhejiang Province(20051313)
文摘In 1984, Isaacs proposed the theories of Bπ-character and Iπ-character in π-separated group. This paper gives some new extension conditions of Iπ characters.
基金the National Natural Science Foundation of China (No. 50708094)the Hi-Tech Research and Development Program (863) of China (No. 2007AA11Z216)
文摘This paper is concerned with the issue of stabilization for the linear neutral systems with mixed delays. The attention is focused on the design of output feedback controllers which guarantee the asymptotical stability of the closed-loop systems. Based on the model transformation of neutral type, the Lyapunov-Krasovskii functional method is employed to establish the delay-dependent stability criterion. Then, through the controller parameterization and some matrix transformation techniques, the desired parameters are determined under the delay-dependent design condition in terms of linear matrix inequalities (LMIs), and the desired controller is explicitly formulated. A numerical example is given to illustrate the effectiveness of the proposed method.
文摘The financial crisis in late 2008 arrested economic development in the construction sector in the Middle East, with the result that investors＇ confidence in the sector is severely depressed. Delays constitute one of the highest impediments to project success. In this respect, the traditional management is no longer sufficient for construction project success. The objective of this study is to conduct a literature review to identify additional effective measures for controlling the potential delays risks in construction projects in order to maximize the opportunities for success in those projects. Thirty-six scholarly articles published between 2000 and 2011 are reviewed to identify related MDRC （measures for delays risks control）. This survey reveals that 60% of the studies are related to decision-making, performance, risk management variations and poor management knowledge of stakeholders and that 20% of these studies are undertaken in the Middle East. A further 25% of the studies are related to the lack of financial risk by stakeholders, and of these 14% are in the Middle East. A knowledge gap is identified in terms of project performance, stakeholder management and risk management, which are seen as significant measures of success in controlling project delay.
基金Project (Nos. 60434020 and 60604003) supported by the NationalNatural Science Foundation of China
文摘The design problem of delay-dependent robust control for uncertain discrete singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm-bounded. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent robust stability condition is derived and expressed in terms of linear matrix inequalities (LMIs). A suitable robust state feedback control law is presented, which guarantees that the resultant closed-loop system is regular, causal and stable for all admissible uncertainties. Numerical examples are given to demonstrate the applicability of the proposed method.
文摘In recent years,our country entered the stage of population aging, and this trend continues to increase. Young population declining dependency ratios and the elderly support ratio is growing.Many phenomena are heralds the retirement policy must introduce.At the same time, the adjustment of the legal retirement age for women, is also a concern hot spot and a topic of heated academia discussion in politics. As the extension of life expectancy, especially women to longer life expectancy and the education of the extension of women＇s status, ability to work has been greatly improved. Based on the change of various factors, delay retirement age for women in China＇s reform is imperative. This paper studies from the perspective of social justice, to the reform of the current situation of the development in our country and foreign experience to research the method of combining the draw delay retirement outstanding aspects of influence on female workers. From a personal health, family factors, career, personal value Suggestions such as, in order to Perfect delay enterprise female worker retirement age policy scheme and implement supporting measures.
