乡村振兴对城乡收入差距影响的空间异质性与分位效应——多维度下基于贝叶斯时空分位回归模型的实证

为了精确了解乡村振兴对城乡收入差距的影响,该文利用泰尔指数和熵权法对城乡收入差距与乡村振兴进行评价,利用贝叶斯时空分位回归模型实证分析了乡村振兴对城乡收入差距影响的空间异质性和分位效应。研究表明:乡村振兴有助于缩小城乡收入差距,其中产业兴旺和生活富裕的反向作用最大;乡村振兴对城乡收入差距的影响存在空间异质性,产业兴旺、治理有效和生活富裕在西南及西北地区的反向作用最明显,生态宜居主要体现在东部地区,乡风文明主要表现在中部和东北地区;乡村振兴对城乡收入差距的反向作用存在分位效应,产业兴旺的反向作用边际随着分位水平的提升而上升,生态宜居的反向作用边际呈现“V型”,乡风文明和治理有效的反向作用边际随着分位水平的提升而下降,生活富裕的反向作用边际呈现“倒V型”。

基于偏最小二乘路径模型的分位效应测度

对于偏最小二乘路径模型的效应分析,为了测度路径模型的分位效应,文章首先给出了偏最小二乘路径模型建模的具体过程.其次,基于潜变量得分与分位回归提出估计平滑分位效应的方法,给出了平滑分位效应的Bootstrap置信带的算法.最后,考虑顾客满意度的分位异质性,对满意度模型的分位效应进行分析.结论表明,该方法是对传统偏最小二乘路径模型的一种补充且可获得更有深度的决策信息.

Theoretical Study on Stereodynamics of Reactions of N（^2D）＋H2→NH＋H and N（^2D）＋D2→ND＋D

The vector correlations between products and reagents for the title reactions have been calculated by the quasi-classical trajectory method at a collision energy of 21.32 kJ/mol on an accurate potential energy surface of Ho et al. （J. Chem. Phys. 119, 3063 （2003））. The peaks of the product angular distribution are found to be in both backward and forward directions for the two title reactions. The product rotational angular momentum is not only aligned, but also oriented along the negative direction of y-axis. These theoretical results are in good agreement with recent experimental findings for the two title reactions. The isotopic effect is also revealed and primarily attributed to the difference of the mass factor in the two title reactions.

基于无条件分位回归的民营上市公司高管薪酬问题研究

高级管理人员的薪酬作为现代企业委托代理关系中的核心问题一直是社会的焦点.本文以我国民营上市公司为样本,首先研究了公司规模、每股收益、营业收入、流动负债和高管持股比例作用于高管薪酬不同分位点处的条件分位偏效应,结果表明它们在不同分位水平下的影响各异;然后为了获得这些因素的一般边际影响,利用无条件分位回归分析了它们的无条件分位偏效应,结果指出公司规模、每股收益和营业收入与各个分位水平的高管薪酬呈不同程度的正相关而流动负债则为负相关,高管持股比例与低分位水平的高管薪酬正相关而对中高分位水平的影响不显著;最后对相关结果进行了对比,发现每个影响因素的条件和无条件分位偏效应有所区别,并且无条件分位偏效应的解释意义更具有现实价值.

Theoretical Study on Mechanism and Kinetics of Reaction of O（^3p） with Propane

The reaction of C3H8＋O（^3p）→C3HT＋OH is investigated using ab initio calculation and dynamical methods. Electronic structure calculations for all stationary points are obtained using a dual-level strategy. The geometry optimization is performed using the unrestricted second-order Moller-Plesset perturbation method and the single-point energy is computed us- ing the coupled-cluster singles and doubles augmented by a perturbative treatment of triple excitations method. Results indicate that the main reaction channel is C3Hs＋O（^3p）→i- C3HT＋OH. Based upon the ab initio data, thermal rate constants are calculated using the variational transition state theory method with the temperature ranging from 298 K to 1000 K. These calculated rate constants are in better agreement with experiments than those reported in previous theoretical studies, and the branching ratios of the reaction are also calculated in the present work. Furthermore, the isotope effects of the title reaction are calculated and discussed. The present work reveals the reaction mechanism of hydrogenabstraction from propane involving reaction channel competitions is helpful for the understanding of propane combustion.

Nuclear ?eld shift effects on stable isotope fractionation: a review

An anomalous isotope effect exists in many heavy element isotope systems （e.g., Sr, Gd, Zn, U）. This effect used to be called the ＂odd--even isotope effect＂ because the odd mass number isotopes behave differently from the even mass number isotopes. This mass-indepen- dent isotope fractionation driving force, which originates from the difference in the ground-state electronic energies caused by differences in nuclear size and shape, is cur- rently denoted as the nuclear field shift effect （NFSE）. It is found that the NFSE can drive isotope fractionation of some heavy elements （e.g., Hg, T1, U） to an astonishing degree, far more than the magnitude caused by the con- ventional mass-dependent effect （MDE）. For light ele- ments, the MDE is the dominant factor in isotope fractionation, while the NFSE is neglectable. Furthermore, the MDE and the NFSE both decrease as temperatures increase, though at different rates. The MDE decreases rapidly with a factor of 1/T2, while the NFSE decreases slowly with a factor of 1/T. As a result, even at high temperatures, the NFSE is still significant for many heavy element isotope systems. In this review paper, we begin with an introduction of the basic concept of the NSFE, including its history and recent progress, and follow with the potential implications of the inclusion of the NFSE into the kinetic isotope fractionation effect （KIE） and heavy isotope geochronology.

High rank coalbed methane desorption characteristic and its application in production in Qinshui basin

Based on spontaneous desorption characteristic, the correlation of desorption time and gas content was analyzed and the application of it in production was researched. The desorption of high rank coalbed methane in Qinshui basin was periodic, and isotope fractionation effect also exists in the process. △δ^13C1 can be used to distinguish the stabilization of coalbed methane wells, associated with desorption rate, the individual well recoverable reserves can be calculated. Economically recoverable time can be predicted according to the logarithmic relationship between desorption gas content per ton and desorption time. The error between predicted result and numerical simulation result is only 1.5%.

Influence of Deformation on Light Particles as a Probe of Nuclear Dissipation for a Neutron-Deficient ^178Pb System

Using a diffusion model we investigate deformation effects on the sensitivity of different light particles to nuclear dissipation for a rather neutron-deficlent ^178Pb system. Galculations show that deformation significantly increases the sensitivity of neutron emission to dissipation strength, and that this effect becomes stronger with increasing deformation.

Molecular Dynamics Study of Hydrogen Dissociation on Pd Surfaces using Reactive Force Fields

Developing a widely-used reactive force field is meaningful to explore the fundamental reaction mechanism on gas-surface chemical reaction dynamics due to its very high computational efficiency. We here present a study of hydrogen and its deuterated molecules dissociation on Pd surfaces based on a full-dimensional potential energy surface （PES） constructed by using a simple second moment approximation reactive force field （SMA RFF）. Although the descriptions of the adsorbate-substrate interaction contain only the dissociation reaction of H2/Pd（111） system, a good transferability of SMA potential energy surface （PES） is shown to investigate the hydrogen dissociation on Pd（100）. Our simulation results show that, the dissociation probabilities of H2 and its deuterated molecules on Pd（111） and Pd（100） surfaces keep non-monotonous variations with respect to the incident energy Ei, which is in good agreement with the previous ab initio molecular dynamics. Furthermore, for the oriented molecules, the dissociation probabilities of the oriented H2 （D2 and T2） molecule have the same orientation dependence behavior as those oriented HD （HT and DT） molecules.

Variations of Stable Carbon Isotopes of CH4 Emission from Three Typical Rice Fields in China

Little is known about the stable carbon isotopes of methane （CH4） emitted （δ13CH4elnitted） from permanently flooded rice fields and double rice-cropping fields. The CH4 emission and corresponding （δ13CH4emitted under various field managements （mulching, water regime, tillage, and nitrogen （N） fertilization） were simultaneously measured in three typical Chinese rice fields, a permanently flooded rice field in Ziyang City, Sichuan Province, Southwest China, a double-rice cropping field in Yingtan City, Jiangxi Province, Southeast China, and a rice-wheat rotation field in Jurong City, Jiangsu Province, East China, from 2010 to 2012. Results showed different seasonal variations of δ13CH4emitted among the three fields during the rice-growing season. The values of （δ13CH4emitted were negatively correlated with corresponding CH4 emissions in seasonal variation and mean, indicating the importance of CH4 production, oxidation, and transport associated with isotopic fractionation effects to the δ13CH4emitted. Seasonal variations of δ13CH4emltted were slightly impacted by mulching cultivation, tillage, and N application, but highly controlled by drainage. Meanwhile, tillage, N application, and especially mulching cultivation had important effects on seasonal mean CH4 emissions and corresponding δ13CH4emitted with low emissions accompanied by high values of δ13CH4emitted. Seasonal mean values of （δ13CH4emitted from the three fields were similar, mostly ranging from -60‰ to -50‰ which are well in agreement with previously published data. These demonstrated that seasonal variations of （δ13CH4emitted mainly depended on the changes in CH4 emission from rice fields and further indicated the important effects of methanogenic pathways, CH4 oxidation, and CH4 transport associated with isotope fractionation effects influenced by field managements on δ13CH4emitted.

Evaluation of the carbon isotopic effects of NDIR and CRDS analyzers on atmospheric CO2 measurements

Non-dispersive infrared （NDIR） and cavity ring-down spectroscopy （CRDS） CO2 analyzers use 12CO2 isotopologue absorption lines and are insensitive to all or part of other CO2-related isotopologues. This may produce biases in CO2 mole fraction measurements of a sample if its carbon isotopic composition deviates from that of the standard gases being used. To evaluate and compare the effects of carbon isotopic composition on NDIR and CRDS CO2 analyzers, we prepared three test sample air cylinders with varying carbon isotopic abundances and calibrated them against five standard cylinders with ambient carbon isotopic composition using CRDS and NDIR systems. We found that the CO2 mole fractions of the sample cylinders measured by G1301 （CRDS） were in good agreement with those measured by LoFlo （NDIR）. The CO2 values measured by both instruments were higher than that of a CO2 isotope measured by G2201i （CRDS） analyzer for a test cylinder with depleted carbon isotopic composition δ^13C =-36.828%0, whereas no obvious difference was found for other two test cylinders with 3 δ^13C=-8.630‰ and δ^13C=-15.380‰, respectively. According to the theoretical and experimental results, we concluded that the total CO2 mole fractions of samples with depleted isotopic compositions can be corrected on the basis of their 12CO2 values calibrated by standard gases using LoFlo and G1301 if the fi13C and fi180 values are known. Keywords NDIR and CRDS analyzers, Carbon isotopic effects, CO2 measurements

Bonded excimer in stacked adenines:Semiclassical simulations

The nonradiative decay of a n-stacked pair of adenine molecules, one of which was excited by an ultrafast laser pulse, is studied by semiclassical dynamics simulations. This simulation investigation is focused on the effect of the formation of bonded excimer in stacked adenines on the mechanism of ultrafast decay. The simulation finds that the formation of the bond- ed excimer significantly lowers the energy gap between the LUMO and HOMO and consequently facilitates the deactivation of the electronically excited molecule. On the other hand, the formation of the chemical bond between two stacked adenines re- stricts the deformation vibration of the pyrimidine of the excited molecule due to the steric effect. This slows down the formation of the coupling between the HOMO and LUMO energy levels and therefore delays the deactivation process of the excited adenine molecule to the electronic ground state.