为了研究烟草脉斑驳病毒(TVMV)侵染本氏烟的抗病分子机制, 本文建立了TVMV转录组数据库, 挖掘抗病相关基因以及代谢和信号通路, 采用Illumina Novaseq 6000高通量测序平台对侵染TVMV的本氏烟进行转录组测序, 并进行生物信息学分析; 利用R package: edge R等软件分析了有关抗病的差异表达基因, 对差异表达基因进行基因本体论(GO)及京都基因和基因组百科全书(KEGG)基于途径的通路富集分析。基于TVMV侵染本氏烟转录组的测序结果中共获得4 593个差异表达基因, 其中3 564个基因上调表达, 1 029个基因下调表达。共筛选出10个抗病相关的差异表达显著基因, 6个上调, 4个下调。GO数据库中注释到生物学过程、细胞组分及分子功能等三大类共50个功能组。其中, 在第三大类分子功能中, 蛋白质结合功能以及ATP结合功能所涉及的差异表达基因最显著, 分别为501个和453个差异基因。KEGG共富集20条通路, 注释到核糖体途径的差异基因富集程度最高, 基因最显著, 差异表达基因数为307个。蛋白质结合、ATP结合、核糖体、真核生物核糖体的生物反应、DNA复制(DNA replication)等通路可能在调控本氏烟抗TVMV病毒中起着重要作用。通过对转录组中筛选的差异表达基因进行分析研究, 为后续本氏烟抗TVMV病毒的深入研究奠定了重要的基础。

Considering the changes of the geometric shielding effect in a molecule as the incident electron energy varing, an empirical fraction, which is dependent on the incident electron energy, is presented. Using this empirical fraction, the total cross sections (TCSs) for electrons scattering from complex polyatomic molecules C2F4 and SO2 are calculated over a wide energy range from 30 to 5000 eV together with the additivity rule model at Hartree-Fock level. In the TCS calculations, the atoms are presented by the spherical complex optical potential, which is composed of static, exchange, polarization and absorption contributions. The quantitative TCSs above 100 eV are in good agreement with those obtained by experiments and other theories. It is proved that the empirical fraction, which exhibits the TCS contributions of shielded atoms in a molecule at different energies, is reasonable.

The total (elastic plus inelastic) cross sections for positron scattering from N2 and CO2 over the incident energy range from 30 to 3000eV are calculated using the additivity rule model at Hartree-Fock level. A complex optical model potential modified by incorporating the concept of bonded atom, which takes into account the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cross section of positron-molecule scattering. The calculated total cross sections are in good agreement with those reported by experiments and other theories over a wide energy range.

A deuterium cluster jet produced in the supersonic expansion into vacuum of deuterium gas at liquid nitrogen temperature and moderate backing pressures is studied by Rayleigh scattering techniques. The experimental results show that deuterium clusters can be created at moderate gas backing pressures ranging from 8 to 23 bar, and a maximum average cluster size of 350 atoms per cluster is estimated. The temporal evolution of the cluster jet generated at the backing pressure of 20 bar demonstrates a two-plateau structure. The possible mechanism responsible for this structure is discussed. The former plateau with higher average atom and cluster densities is more suitable for the general laser-cluster interaction experiments.

The accurate dissociation energy and equilibrium geometry of the b3Π state of 7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated results are 0.2580 eV and 0.1958 nm for the dissociation energy and equilibrium geometry, respectively. The whole potential energy curve for the b3Π state is also calculated over the internuclear separation range from about 0.10 to 0.54 nm. The results are fitted by the Murrell-Sorbie function. It is found that the Murrell-Sorbie function form, which is mainly used to fit the ground-state potential energy function, is well suitable for the excited triplet b3Π state. The vertical excitation energy from the ground state to the b3Π state is calculated to be 4.233 eV. Based on the analytic potential energy function, the harmonic frequency of 610.88 cm^(-1) about this state is firstly estimated. Compared with other theoretical results, this work is the most complete effort to deal with the analytic potential energy function and the harmonic frequency of this state.

A complex optical model potential correlated by the concept of bonded atoms, which considers the overlapping effect of electron clouds between two atoms in a molecule, is firstly employed to calculate the absolute differential cross sections, the integrated and momentum transfer cross sections for electrons scattered by O2 at intermediate and high energies by using additivity rule model at Hartree-Fock level. In the study, the complex optical model potential is composed of static, exchange, correlation polarization plus absorption contributions. The quantitative absolute differential cross sections, the integrated and momentum transfer cross sections are obtained. Compared with available experimental data, this approach presents good results. It is shown that the additivity rule model together with the complex optical model potential correlated by the concept of bonded atoms is completely suitable for the calculations of the absolute differential cross sections, the integrated and momentum transfer cross sections.