We test whether differences in the background characteristics of firms’chairperson and CEO can reduce management agency costs.We find that when the chairperson is older,has a higher level of education,and has more ov...We test whether differences in the background characteristics of firms’chairperson and CEO can reduce management agency costs.We find that when the chairperson is older,has a higher level of education,and has more overseas experience than the CEO,the management agency costs will be lower.A series of robustness tests do not change our conclusions.In further analysis,we find that the negative relationship between the two is more significant for SOEs or firms experiencing fierce market competition.Finally,we also find that the chairman-CEO’s vertical dyad background characteristics differences can help to improve firm performance.Our study provides theoretical and practical implications for companies on how to best configure their top management team.展开更多
Three novel symmetrical 4.4＇-difluoro-4-bora-3a,4a-diaza-sindacene（BODIPY） derivatives were synthesized via a general and efficient protocol. These BODIPY dyads bear a diverse aryl linker bridge in the middle and t...Three novel symmetrical 4.4＇-difluoro-4-bora-3a,4a-diaza-sindacene（BODIPY） derivatives were synthesized via a general and efficient protocol. These BODIPY dyads bear a diverse aryl linker bridge in the middle and two BODIPY units at the termini. The photophysical properties of these dyads were investigated by ultravioletvisible（UV-Vis） absorption and emission spectroscopy. And their electrochemical properties were studied by cyclic voltammetry. The absorption of these dyads showed slightly blue shift and the intramolecular charge transfer（ICT） state under,vent ultrafast direct surface crossing to the ground state with high degree of rotational freedom. The results will be useful for the further functionalization of these novel symmetrical BODIPY derivatives.展开更多
A full-relaxation optimization of molecule and the Dreiding force field are employed to obtain the geometry parameters and the conformational energy surfaces of meso or racemic dyad of poly(acrylic acid) (PAA) and pol...A full-relaxation optimization of molecule and the Dreiding force field are employed to obtain the geometry parameters and the conformational energy surfaces of meso or racemic dyad of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA). Three different carbonyl-bond orientations of side-groups resulted in the differences in depth of potential wells in their energetic contours for a meso or a racemic dyad. These discrepancies are interpreted as a result of various fine structures corresponding to grid search conformations as well as thereby different interactions. The analysis on the most stable conformations of PMAA confirmed that the ester groups are nearly perpendicular to the plane defined by the two adjacent skeletal bonds but may possibly change their relative orientations to meet the requirement of lower energy during the conformational state transition. For each polymer, two global energy maps of a meso and a racemic dyad were finally constructed from the superposition of energy data for the three kinds of side-group orientations by the Boltzmann factors. From an ensemble average, the proposed scheme with three rotational isomeric states (RIS) allowed us to access the experimentally unperturbed dimensions of PAA chain via the configurational statistical mechanics. Although the calculation was based on the short-range, local interactions, it was interested to note that the experimental characteristic ratios just fell within the range calculated for atactic chains.展开更多
Nowadays the number of cores that are integrated into NoC (Network on Chip) systems is steadily increasing, and real application traffic, running in such multi-core environments requires more and more bandwidth. In th...Nowadays the number of cores that are integrated into NoC (Network on Chip) systems is steadily increasing, and real application traffic, running in such multi-core environments requires more and more bandwidth. In that sense, NoC architectures should be properly designed so as to provide efficient traffic engineering, as well as QoS support. Routing algorithm choice in conjunction with other parameters, such as network size and topology, traffic features (time and spatial distribution), as well as packet injection rate, packet size, and buffering capability, are all equivalently critical for designing a robust NoC architecture, on the grounds of traffic engineering and QoS provision. In this paper, a thorough numerical investigation is achieved by taking into consideration the criticality of selecting the proper routing algorithm, in conjunction with all the other aforementioned parameters. This is done via implementation of four routing evaluation traffic scenarios varying each parameter either individually, or as a set, thus exhausting all possible combinations, and making compact decisions on proper routing algorithm selection in NoC architectures. It has been shown that the simplicity of a deterministic routing algorithm such as XY, seems to be a reasonable choice, not only for random traffic patterns but also for non-uniform distributed traffic patterns, in terms of delay and throughput for 2D mesh NoC systems.展开更多
Dyad and triad census summarize much of the network level structural information of a given directed network. They have been found very useful in analyzing structural properties of social networks. This study aims to ...Dyad and triad census summarize much of the network level structural information of a given directed network. They have been found very useful in analyzing structural properties of social networks. This study aims to explore crisis communication network by following dyad and triad census analysis approach to investigate the association of microlevel communication patterns with organizational crisis. This study further tests hypothesis related to the process of data generation and tendency of the structural pattern of transitivity using dyad and triad census output. The changing communication network at Enron Corporation during the period of its crisis is analyzed in this study. Significant differences in the presence of different isomorphism classes or microlevel patterns of both dyad and triad census are noticed in crisis and non-crisis period network of Enron email corpus. It is also noticed that crisis communication network shows more transitivity compared to the non-crisis communication network.展开更多
A series oftri（alkoxyl）benzene-fullerene dyads（PCBB-Cn, n=4, 6, 8, 10, 12） with varied tri（alkoxyl） chain lengths was designed, synthesized and used as acceptor materials in polymer solar cells（PSCs）. The five...A series oftri（alkoxyl）benzene-fullerene dyads（PCBB-Cn, n=4, 6, 8, 10, 12） with varied tri（alkoxyl） chain lengths was designed, synthesized and used as acceptor materials in polymer solar cells（PSCs）. The five fullerene dyads possess similar absorption spectra in dilute solution, decreased glass-transition temperature（Tg） and gradually elevated lowest unoccupied molecular orbital（LUMO） energy levels from -3.87 eV to -3.73 eV with the increase of the alkoxy chain length. In the fabrication of PSCs with poly（3-hexylthiophene）（P3HT） as donor and the fullerene dyads as acceptor, PCBB-Cn with longer tri（alkoxyl） chains and lower Tg can induce crystalline structure of P3HT during spin-coating the photoactive layer at room temperature and form nanoscale phase separated interpenetrating network of P3HT：PCBB-Cn blend films, which results in the improvement of photovoltaic performance of PSCs. A power conversion efficiency of 3.03% for the PSCs based on P3HT：PCBB-C10 was obtained without thermal annealing or solvent annealing. The thermal and solvent annealing-free fabrication using the fullerene dyads as acceptor is very important for the roll to roll production of PSCs with flexible large area.展开更多
Group living provides various advantages to individuals in regards to protection avoidance,intergroup competition,productive success and social information.Stable one-male units(OMUs)consist of relationships between t...Group living provides various advantages to individuals in regards to protection avoidance,intergroup competition,productive success and social information.Stable one-male units(OMUs)consist of relationships between the adult females and the resident male as well as the relationships among adult females.Based on continuous observation of a reproductive group of golden snub-nosed monkeys(Rhinopithecus roxellana)in the Qinling Mountains,we analyzed the relationships among adult individual dyads within 4 OMUs.The results indicated that in golden snub-nosed monkey societies,females not only had no strong tendency to build a relationship with the resident male in the OMU but also had no strong tendency to build relationships with other females in the OMU.In comparison with hamadryas(Papio hamadryas)and gelada baboons(Theropithecus gelada),the relationships within golden snub-nosed monkeys OMUs showed neither the star-shaped pattern observed in hamadryas baboons nor the net-shaped pattern observed in gelada baboons.We concluded that the relationships within golden snub-nosed monkey OMUs indicated a third pattern in nonhuman primate societies.Future research is required to determine the potential mechanisms for such a pattern.展开更多
Two donor-σ-acceptor molecular systems incorporating tetrathiafulvalene(TTF)and tetraphenylpor-phyrin(TPP)units,TTF-TPP(dyad 1)and TTF-TPP-TTF(triad 2),were synthesized.Both dyad 1 and triad 2 and their synthetic int...Two donor-σ-acceptor molecular systems incorporating tetrathiafulvalene(TTF)and tetraphenylpor-phyrin(TPP)units,TTF-TPP(dyad 1)and TTF-TPP-TTF(triad 2),were synthesized.Both dyad 1 and triad 2 and their synthetic intermediates have been characterized by 1H nuclear magnetic resonance(1H NMR)and mass spectro-graphy(MS).Their ultraviolet and visible spectroscopy(UV-Vis)and cyclic voltammetry(CV)showed negligible intramolecular charge transfer interaction in their ground states.Theirfluorescence intensity was strongly quenched compared with TPP,which implied the photoinduced electron transfer occurred from the TTF unit to the TPP unit in the excited state.On the other hand,theirfluorescence intensity could be modulated by sequential oxidation of the TTF unit using chemical methods,which exhibited their potential application influorescence molecular switch.展开更多
The molecular aggregation state of a porphyrin-perylenediimide dyad can be changed by treating with trifluoroacetic acid. Transmittance electron microscopy (TEM) images revealed that lamella micro- structures were for...The molecular aggregation state of a porphyrin-perylenediimide dyad can be changed by treating with trifluoroacetic acid. Transmittance electron microscopy (TEM) images revealed that lamella micro- structures were formed when the dyad precipitated from neutral solvent, but spherical nano-particles were obtained when precipitating from acidic solution. X-ray diffraction patterns showed that the la- mella microstructures and the nanoparticles were polycrystalline and amorphous solids, respectively. By using rational perylenediimide and porphyrin as reference compounds, careful analyses on the UV-visible spectra of the dyad and the references under different conditions were conducted and the results demonstrated that both the porphyrin and perylendiimide subunits of the dyad took J-aggregation in neutral solvent, but after being treated with trifluoroacetic acid and chloroform solu- tion, the perylenediimide subunit changed to an H-aggregation while the porphyrin subunits changed to a random packing mode.展开更多
基金supported by National Natural Science Foundation of China[Grant No 72072060,71602059]Soft Science Research Project of Guangdong Province,China[grant numbers2020A1010020004]+1 种基金“13th Five-year Plan”for the Development of Philosophy and Social Sciences of Guangzhou,Joint construction projects in 2020,China[grant numbers 2020GZGJ11]Fundamental Research Funds for the Central Universities of the South China University of Technology,China[grant numbers XYMS202104]
文摘We test whether differences in the background characteristics of firms’chairperson and CEO can reduce management agency costs.We find that when the chairperson is older,has a higher level of education,and has more overseas experience than the CEO,the management agency costs will be lower.A series of robustness tests do not change our conclusions.In further analysis,we find that the negative relationship between the two is more significant for SOEs or firms experiencing fierce market competition.Finally,we also find that the chairman-CEO’s vertical dyad background characteristics differences can help to improve firm performance.Our study provides theoretical and practical implications for companies on how to best configure their top management team.
基金the National Natural Science Foundation of China
文摘Three novel symmetrical 4.4＇-difluoro-4-bora-3a,4a-diaza-sindacene（BODIPY） derivatives were synthesized via a general and efficient protocol. These BODIPY dyads bear a diverse aryl linker bridge in the middle and two BODIPY units at the termini. The photophysical properties of these dyads were investigated by ultravioletvisible（UV-Vis） absorption and emission spectroscopy. And their electrochemical properties were studied by cyclic voltammetry. The absorption of these dyads showed slightly blue shift and the intramolecular charge transfer（ICT） state under,vent ultrafast direct surface crossing to the ground state with high degree of rotational freedom. The results will be useful for the further functionalization of these novel symmetrical BODIPY derivatives.
基金This work was supported by the Youth Science Foundation of Acedemia Sinica the China Postdoctoral Science Foundation, the National Natural Science Foundation of China, and Polymer Physics Laboratory,Academia Sinica
文摘A full-relaxation optimization of molecule and the Dreiding force field are employed to obtain the geometry parameters and the conformational energy surfaces of meso or racemic dyad of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA). Three different carbonyl-bond orientations of side-groups resulted in the differences in depth of potential wells in their energetic contours for a meso or a racemic dyad. These discrepancies are interpreted as a result of various fine structures corresponding to grid search conformations as well as thereby different interactions. The analysis on the most stable conformations of PMAA confirmed that the ester groups are nearly perpendicular to the plane defined by the two adjacent skeletal bonds but may possibly change their relative orientations to meet the requirement of lower energy during the conformational state transition. For each polymer, two global energy maps of a meso and a racemic dyad were finally constructed from the superposition of energy data for the three kinds of side-group orientations by the Boltzmann factors. From an ensemble average, the proposed scheme with three rotational isomeric states (RIS) allowed us to access the experimentally unperturbed dimensions of PAA chain via the configurational statistical mechanics. Although the calculation was based on the short-range, local interactions, it was interested to note that the experimental characteristic ratios just fell within the range calculated for atactic chains.
文摘Nowadays the number of cores that are integrated into NoC (Network on Chip) systems is steadily increasing, and real application traffic, running in such multi-core environments requires more and more bandwidth. In that sense, NoC architectures should be properly designed so as to provide efficient traffic engineering, as well as QoS support. Routing algorithm choice in conjunction with other parameters, such as network size and topology, traffic features (time and spatial distribution), as well as packet injection rate, packet size, and buffering capability, are all equivalently critical for designing a robust NoC architecture, on the grounds of traffic engineering and QoS provision. In this paper, a thorough numerical investigation is achieved by taking into consideration the criticality of selecting the proper routing algorithm, in conjunction with all the other aforementioned parameters. This is done via implementation of four routing evaluation traffic scenarios varying each parameter either individually, or as a set, thus exhausting all possible combinations, and making compact decisions on proper routing algorithm selection in NoC architectures. It has been shown that the simplicity of a deterministic routing algorithm such as XY, seems to be a reasonable choice, not only for random traffic patterns but also for non-uniform distributed traffic patterns, in terms of delay and throughput for 2D mesh NoC systems.
文摘Dyad and triad census summarize much of the network level structural information of a given directed network. They have been found very useful in analyzing structural properties of social networks. This study aims to explore crisis communication network by following dyad and triad census analysis approach to investigate the association of microlevel communication patterns with organizational crisis. This study further tests hypothesis related to the process of data generation and tendency of the structural pattern of transitivity using dyad and triad census output. The changing communication network at Enron Corporation during the period of its crisis is analyzed in this study. Significant differences in the presence of different isomorphism classes or microlevel patterns of both dyad and triad census are noticed in crisis and non-crisis period network of Enron email corpus. It is also noticed that crisis communication network shows more transitivity compared to the non-crisis communication network.
基金Supported by the National Natural Science Foundation of China（Nos.21204057, 91333204）, the Natural Science Foundation of Jiangsu Province, China（No.BK2012213）, the Priority Academic Development Program of Jiangsu Higher Education Institutions, China and the Soochow University Undergraduate Training Program for Innovation and Entrepreneurship, China（No.2013XjOZO）.
文摘A series oftri（alkoxyl）benzene-fullerene dyads（PCBB-Cn, n=4, 6, 8, 10, 12） with varied tri（alkoxyl） chain lengths was designed, synthesized and used as acceptor materials in polymer solar cells（PSCs）. The five fullerene dyads possess similar absorption spectra in dilute solution, decreased glass-transition temperature（Tg） and gradually elevated lowest unoccupied molecular orbital（LUMO） energy levels from -3.87 eV to -3.73 eV with the increase of the alkoxy chain length. In the fabrication of PSCs with poly（3-hexylthiophene）（P3HT） as donor and the fullerene dyads as acceptor, PCBB-Cn with longer tri（alkoxyl） chains and lower Tg can induce crystalline structure of P3HT during spin-coating the photoactive layer at room temperature and form nanoscale phase separated interpenetrating network of P3HT：PCBB-Cn blend films, which results in the improvement of photovoltaic performance of PSCs. A power conversion efficiency of 3.03% for the PSCs based on P3HT：PCBB-C10 was obtained without thermal annealing or solvent annealing. The thermal and solvent annealing-free fabrication using the fullerene dyads as acceptor is very important for the roll to roll production of PSCs with flexible large area.
基金funded by grants from the Key Program of National Natural Science Fund(31130061)the Special Foundation of Shaanxi Academy of Sciences,China(2012K-01)+4 种基金the Youth Foundation of Shaanxi Academy of Sciences,China(2013K-35)the Western Light Talent Culture Project(2011DF05)the National Nature Science Foundation of China(30970444,30970168,30970379)the Research Fund for the Doctoral Program of Higher Education of China(20106101110005)the Cosmo Oil Eco Card Fund of Japan(2005–2012).
文摘Group living provides various advantages to individuals in regards to protection avoidance,intergroup competition,productive success and social information.Stable one-male units(OMUs)consist of relationships between the adult females and the resident male as well as the relationships among adult females.Based on continuous observation of a reproductive group of golden snub-nosed monkeys(Rhinopithecus roxellana)in the Qinling Mountains,we analyzed the relationships among adult individual dyads within 4 OMUs.The results indicated that in golden snub-nosed monkey societies,females not only had no strong tendency to build a relationship with the resident male in the OMU but also had no strong tendency to build relationships with other females in the OMU.In comparison with hamadryas(Papio hamadryas)and gelada baboons(Theropithecus gelada),the relationships within golden snub-nosed monkeys OMUs showed neither the star-shaped pattern observed in hamadryas baboons nor the net-shaped pattern observed in gelada baboons.We concluded that the relationships within golden snub-nosed monkey OMUs indicated a third pattern in nonhuman primate societies.Future research is required to determine the potential mechanisms for such a pattern.
基金supported by the National Natural Science Foundation of China(Grant Nos.21076078 and 20676036).
文摘Two donor-σ-acceptor molecular systems incorporating tetrathiafulvalene(TTF)and tetraphenylpor-phyrin(TPP)units,TTF-TPP(dyad 1)and TTF-TPP-TTF(triad 2),were synthesized.Both dyad 1 and triad 2 and their synthetic intermediates have been characterized by 1H nuclear magnetic resonance(1H NMR)and mass spectro-graphy(MS).Their ultraviolet and visible spectroscopy(UV-Vis)and cyclic voltammetry(CV)showed negligible intramolecular charge transfer interaction in their ground states.Theirfluorescence intensity was strongly quenched compared with TPP,which implied the photoinduced electron transfer occurred from the TTF unit to the TPP unit in the excited state.On the other hand,theirfluorescence intensity could be modulated by sequential oxidation of the TTF unit using chemical methods,which exhibited their potential application influorescence molecular switch.
基金the National Natural Science Foundation of China (Grant Nos. 50573065 and 50573019)the Natural Science Foundation of Zhejiang Province of China (Grant No. Z406018)
文摘The molecular aggregation state of a porphyrin-perylenediimide dyad can be changed by treating with trifluoroacetic acid. Transmittance electron microscopy (TEM) images revealed that lamella micro- structures were formed when the dyad precipitated from neutral solvent, but spherical nano-particles were obtained when precipitating from acidic solution. X-ray diffraction patterns showed that the la- mella microstructures and the nanoparticles were polycrystalline and amorphous solids, respectively. By using rational perylenediimide and porphyrin as reference compounds, careful analyses on the UV-visible spectra of the dyad and the references under different conditions were conducted and the results demonstrated that both the porphyrin and perylendiimide subunits of the dyad took J-aggregation in neutral solvent, but after being treated with trifluoroacetic acid and chloroform solu- tion, the perylenediimide subunit changed to an H-aggregation while the porphyrin subunits changed to a random packing mode.
