湿斜压热动力耦合强迫激发辐合增长和暴雨维持的一种机制

打破将散度演化分析局限于水平动力学框架内的传统认识思维,针对大气的斜压性与层结特征将对大气运动散度场演化产生显著影响的事实,从湿斜压原始方程出发,将大气的斜压热力作用通过热力学方程引入散度方程,在替换平衡近似（alternative balance）下,导出了显式包含湿非地转Q矢量与垂直风切变耦合强迫作用的新型散度方程.阐明了潮湿大气中非地转斜压强迫激发散度场演化的物理机制,为利用常规观测资料诊断散度场演化提供了一种有效的数学工具.通过对流层中低层气柱内总体辐合增长影响因子的分 关键词： 暴雨天气 散度演变 正压非平衡强迫 湿斜压热动力耦合强迫     

碳纳米管网络导电特征的导电型原子力显微镜研究

利用导电型原子力显微镜对大范围碳纳米管（CNT）网络的导电性能进行成像观察.研究发现：在几十微米的成像范围内,每根CNT本身的电阻远小于CNT之间的接触电阻,以致于在电压偏置的网络中不同的CNT呈现电位不同的等位体;CNT的导电性能虽不因与其他CNT的交叠接触而改变,但是如果缠绕成束,则半导体性CNT趋于呈现金属性CNT的导电特征. 关键词： 导电型原子力显微镜 碳纳米管网络 碳管纳米电导     

高电荷态离子$lt;sup$gt;126$lt;/sup$gt;Xe$lt;sup$gt;$lt;i$gt;q$lt;/i$gt;+$lt;/sup$gt;引起GaN表面形貌变化研究

用不同电荷态的¹²⁶Xe^q+离子（9≤q≤30）在室温下轰击GaN晶体表面,经原子力显微镜分析表明,当q>18,辐照区域由隆起转为显著的刻蚀.被轰击后的GaN晶体表面形貌主要取决于入射离子的电荷态.同时,样品表面形貌还与入射离子的剂量和入射角有关;在实验参数范围,与入射离子的初动能没有明显关系（180 keV≤E_k≤600 keV）.当入射离子的电荷态q=18,与样品表面法线成60°角倾斜入射和垂直表面入射时,样品的表面几乎没有变化,只是倾斜入射后有很微小的隆起;当q＜18时,样品表面膨胀隆起,粗糙度增强,倾斜入射时表面隆起比垂直入射时更明显,而且都有清晰的峰状分界区;当q＞18时,样品表面被蚀刻呈凹陷状,有明显的齿状刻痕,且侵蚀深度与离子剂量近似呈线性关系,倾斜入射时的刻蚀深度大于垂直入射时的刻蚀深度. 关键词： 高电荷态离子 GaN晶体 原子力显微镜 表面形貌     

Deconfinement phase transition in neutron star matter

The transition from hadron phase to strange quark phase in dense matter is investigated. Instead of using the conventional bag model in quark sect, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates, with a thermodynamic problem improved. In nuclear slot, we adopt the equation of state from Brueckner-Bethe-Goldstone approach with three-body force. It is found that the mixed phase can occur, for reasonable confinement parameter, near the normal saturation density, and transit to pure quark matter at 4—5 times the saturation, which is quite different from the previous results from other quark models that pure quark phase can not appear at neutron-star densities.     

Stability of the magnetic domain structure of nanoparticle thin films against external fields

We investigate the effect of external magnetic fields on the magnetic structure of thin films from magnetic nanoparticles (MNP) with dipolar interaction. Such fields are present, for example, if samples are scanned with magnetic probes. Numerical simulations and experimental magnetic force microscopy (MFM) studies are presented. Numerically, we have calculated the magnetization pattern of single-layer and multilayer MNP thin films. The calculations show that unperturbed single-layer MNP films have an in-plane orientation of the magnetization with a flux-closure-domain pattern. An external field generated by a point dipole above the film induces locally an out-of-plane configuration of the magnetization. In the corresponding MFM images, the domain pattern in the film is erased and a stripe-like contrast enhancement at the edges appears. Multilayer films are found to be more robust against external fields than monolayers.     

The formation of a dislocation spiral on the (101) face of a monoclinic lysozyme crystal: High-resolution experiments

The elementary processes of crystal growth in the case of a low kink density on step edges have been studied by in situ atomic force microscopy. High-resolution images of the first turn of the polygonal dislocation spiral on the (101) face of monoclinic lysozyme crystals, which allow one to discern separate crystal cells, have been obtained. It has been shown that the dependence of the spiral segment velocity on its length is inconsistent with the Gibbs-Thomson law and is represented by several rectilinear sections. The results were explained by taking into account the features of the growth of crystals with a low kink density at low supersaturation.     

Nanoscale formation mechanism of conducting filaments in NiO thin films

We have studied the nanoscale electrical properties of NiO thin films by using conducting atomic force microscopy (CAFM) to understand the mechanism of resistance change of the NiO thin films as we changed the applied voltage. We observed that inhomogeneous conducting filaments were generated by external voltage bias; in addition, some of the inhomogeneous conducting filaments were durable while some of them were not, and they disappeared. We deduced that the resistance change of the NiO thin films was related to inhomogeneous filamentary conducting paths generated by both Ni ions in thermodynamically unstable NiO and the existence of conducting filament segments generated by high voltage bias.     

Equilibrium structure of protonated cyanogen, HNCCN

The cubic force field of protonated cyanogen, HNCCN⁺, has been calculated at the CCSD(T) level of theory employing correlation consistent bases of quadruple-zeta quality. Semi-experimental equilibrium structures have then been derived from the experimental ground-state rotational constants available for various isotopologues and the corresponding vibrational corrections calculated from the theoretical force fields. While a good agreement has been found with the pure theoretical best estimate of equilibrium geometry, computed at the CCSD(T) level of theory accounting for basis set truncation as well as including core correlation corrections, large discrepancies have been noted with the experimental substitution, r_s, as well as effective, r₀, structures.     

Growth of thin polymer films containing side-chain azo-dye analyzed by atomic force microscopy

Thin films containing both the azo-dye disperse red 1 (DR1) and the poly(methylmetacrylate) (PMMA) or the poly(phenylenevinylene) (PPV) are deposited by Langmuir-Blodgett and spin coating techniques on various substrates. The morphology, surface structure and growth pattern of the azo-dye-polymers were studied by atomic force microscopy. Nucleation and growth processes are responsible for the generation of different structures. The spin coated films were additionally oriented using the electric field poling method (corona poling). The film homogeneity is improved by this method in all cases. Due to the polar character of DR1 molecules, rod-like sub-structures are observed after the corona poling process in DR1-MMA films. The indium tin oxide surface enhances reorientation of the azo-dye-polymer molecules during corona poling and results in a significant reduction of the surface roughness.