Capital structure decision is an important issue of corporate finance.Theories show that,the corporate debt ratio is determined by many factors.This study conducts empirical work on capital structure theories,focusing...Capital structure decision is an important issue of corporate finance.Theories show that,the corporate debt ratio is determined by many factors.This study conducts empirical work on capital structure theories,focusing on the corporate data of Chinese listed companies,by considering the intrinsic characteristics,utilizing the principal factor analysis and the ridge regression method.Our results suggest that a firms debt ratio has a positive relationship with its size,profitability and operating risk and has a negative relationship with its growth and non debt tax shield,while the long term leverage has a positive relationship with its collateral value of assets.展开更多
Here we report a quantitative study of the orientational structure and motion of water molecule at the air/water interface. Analysis of Sum Frequency Generation （SFG） vibrational peak of the free O-H stretching band...Here we report a quantitative study of the orientational structure and motion of water molecule at the air/water interface. Analysis of Sum Frequency Generation （SFG） vibrational peak of the free O-H stretching band at 3700 cm^-1 in four experimental configurations showed that orientational motion of water molecule at air/water interface is libratory within a limited angular range. The free OH bond of the interracial water molecule is tilted around 33°from the interface normal and the orientational distribution or motion width is less than 15°. This picture is significantly different from the previous conclusion that the interracial water molecule orientation varies over a broad range within the ultrafast vibrational relaxation time, the only direct experimental study concluded for ultrafast and broad orient, ational motion of a liquid interface by Wei et al. （Phys. Rev. Lett. 86, 4799, （2001）） using single SFG experimental configuration.展开更多
Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H,...Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H, CN, and NC） complexes. Our cal- culations revealed two possible structures for Call2 in CaH2..,HY complexes： linear （I） and bent （II）. The bond lengths, interac- tion energies, and strengths for H...H interactions obtained by both MP2 and B3LYP methods are quite close to each other. It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point. At- om-in-molecule （AIM） results show that for all of Ca-H...H-Y interactions considered here, the Laplacian of the electron densi- ty at the H--.H bond critical point is positive, indicating the electrostatic nature of these Ca-H...H-Y dihydrogen bonded systems.展开更多
文摘Capital structure decision is an important issue of corporate finance.Theories show that,the corporate debt ratio is determined by many factors.This study conducts empirical work on capital structure theories,focusing on the corporate data of Chinese listed companies,by considering the intrinsic characteristics,utilizing the principal factor analysis and the ridge regression method.Our results suggest that a firms debt ratio has a positive relationship with its size,profitability and operating risk and has a negative relationship with its growth and non debt tax shield,while the long term leverage has a positive relationship with its collateral value of assets.
基金This work was supported by Chines Academy of Scieuces（No.CMS-cx200305）,National Natural Science Foundation of China（NSFC No.20425309,No.20573117）and Chinese Ministry of Science and Technology （M0ST No.G1999075305）.
文摘Here we report a quantitative study of the orientational structure and motion of water molecule at the air/water interface. Analysis of Sum Frequency Generation （SFG） vibrational peak of the free O-H stretching band at 3700 cm^-1 in four experimental configurations showed that orientational motion of water molecule at air/water interface is libratory within a limited angular range. The free OH bond of the interracial water molecule is tilted around 33°from the interface normal and the orientational distribution or motion width is less than 15°. This picture is significantly different from the previous conclusion that the interracial water molecule orientation varies over a broad range within the ultrafast vibrational relaxation time, the only direct experimental study concluded for ultrafast and broad orient, ational motion of a liquid interface by Wei et al. （Phys. Rev. Lett. 86, 4799, （2001）） using single SFG experimental configuration.
基金supported by the National Natural Science Foundation of China (20973076,20703021)the Basic Science Research Funding of Jilin University
文摘Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H, CN, and NC） complexes. Our cal- culations revealed two possible structures for Call2 in CaH2..,HY complexes： linear （I） and bent （II）. The bond lengths, interac- tion energies, and strengths for H...H interactions obtained by both MP2 and B3LYP methods are quite close to each other. It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point. At- om-in-molecule （AIM） results show that for all of Ca-H...H-Y interactions considered here, the Laplacian of the electron densi- ty at the H--.H bond critical point is positive, indicating the electrostatic nature of these Ca-H...H-Y dihydrogen bonded systems.
