从量计征还是从价计征?——我看资源税计征方法改革

中央决定资源税改革并且首先将在新疆率先将原油和天然气由现行的从量法计征改为从价法计征。本文从资源税征收的目的和作用出发,分析了从量和从价法计征资源税的各自长处和不足,进而对我国此次资源税计征方法改革提出了从量和从价法并举的看法。

Pseudopotential generation

Different classes of first-principle pseudopotentials are compared and various schemes for pseudopotential generation based on norm conservation are discussed in this paper. BHS (Bachelet, Hamann, and Schlüter)-scheme and V (Vanderbilt)-modifications are used to derive the KB (Kleinman and Bylander)-pseudopotentials and pseudo wave functions of bismuth. Quality test of pseudopotentials shows that no ghost states occur in the logarithmic der ivatives of pseudo wave functions of Bismuth. The obtained bond length of bismuth dimer with this type of pseudopotentials is in good agreement with previous accurately calculate d ab initio quantum chemical result.

Ab Initio Molecular Dynamics Simulation of Liquid Water with Fragmentbased Quantum Mechanical Approach under Periodic Boundary Conditions

In this study,we investigated the structural and dynamical properties of liquid water by using ab initio molecular dynamics simulation under periodic boundary conditions based on the fragment-based quantum mechanical approach.This study was carried out using the second-order Møller-Plesset perturbation theory(MP2)with the aug-cc-pVDZ basis set,which has been validated to be sufficiently accurate for describing water interactions.Diverse properties of liquid water,including radial distribution functions,diffusion coefficient,dipole moment,triplet oxygen-oxygen-oxygen angles,and hydrogen-bond structures,were simulated.This ab initio description leads to these properties in good agreement with experimental observations.This computational approach is general and transferable,providing a comprehensive framework for ab initio predictions of properties of condensed-phase matters.

Spectroscopic Parameters of X^3∑^-, a^1△, and A^＇3△ Electronic States of SO Radical

The potential energy curves （PECs） of three low-lying electronic states （X^3∑, a^1△, and a^3△） of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction （MRCI） approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification （MRCI＋Q）. These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.

Molecular Simulation Studies on Basicity of Nitrogen-containing Compounds

The DFT-based （density fimctional theory） ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum. The results have indicated that there is a distinct relationship between the protonation energy of nitrogen-containing compounds and their basicity. The more negative the protonation energy, the stronger the basicity is. It has been also found that aliphatic amines are more basic than pyridines or aromatic amines, and all these compounds are more basic than pyrroles. The addition of the aromatic rings can influence the basicity of anilines, while the 5- and 6-membered heterocyclic compounds function differently. The solvent properties may affect the basicity of these nitrogen-containing compounds.

Patterning Nanoroads and Quantum Dots on Fluorinated Graphene

Using ab initio methods we have investigated the fluorination of graphene and find that different stoichiometric phases can be formed without a nucleation barrier, with the complete ＂2D-Teflon＂ CF phase being thermody- namically most stable. The fluorinated graphene is an insulator and turns out to be a perfect matrix-host for patterning nanoroads and quantum dots of pristine graphene. The electronic and magnetic properties of the nanoroads can be tuned by varying the edge orientation and width. The energy gaps between the highest occupied and lowest unoccupied molecular orbitals （HOMO-LUMO） of quantum dots are size-dependent and show a confinement typical of Dirac fermions. Furthermore, we study the effect of different basic coverage of F on graphene （with stoichiometries CF and C4F） on the band gaps, and show the suitability of these materials to host quantum dots of graphene with unique electronic properties.