Electron affinity of exotic systems under Debye plasma

Electron affinity of plasma embedded muonium (μ⁺e^?) and pionium (π⁺e^?) has been estimated using a general three‐body formalism within variational framework. Electron correlation is taken care of using extended Hylleraas basis sets. The stability of the three‐body systems have been studied under the Debye screening model of the plasma, which changes the Coulombic potential to the screened Coulomb one. The electron affinity of the muonium and pionium is maximum for free systems, and it decreases gradually toward zero with increase of the plasma strength, which tends to push the three‐body system toward gradual instability. The electron correlation contribution to the affinity has been analyzed. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

分形理论及其在高分子科学中的应用

介绍了分形的基本概念，分形维数的定义及计算方法，讨论了近年来分形理论在高分子科学研究方面的一些应用，内容主要包括高分子溶液、高分子材料的磨损，断裂及界面，高分子结晶过程、导电高分子等。     

Melt‐state polymer chain dimensions as a function of temperature

The unperturbed chain dimensions (〈R²〉_o/M) of cis/trans‐1,4‐polyisoprene, a near‐atactic poly(methyl methacrylate), and atactic polyolefins were measured as a function of temperature in the melt state via small‐angle neutron scattering (SANS). The polyolefinic materials were derived from polydienes or polystyrene via hydrogenation or deuteration and represent structures not encountered commercially. The parent polymers were prepared via lithium‐based anionic polymerizations in cyclohexane with, in some cases, a polymer microstructure modifier present. The polyolefins retained the near‐monodisperse molecular weight distributions exhibited by the precursor materials. The melt SANS‐based chain dimension data allowed the evaluation of the temperature coefficients [dln 〈R²〉_o/dT(κ)] for these polymers. The evaluated polymers obeyed the packing length (p)‐based expressions of the plateau modulus, G = kT/np³ (MPa), and the entanglement molecular weight, M_e = ρN_anp³ (g mol^?1), where n_t denotes the number (～21) of entanglement strands in a cube with the dimensions of the reptation tube diameter (d_t) and ρ is the chain density. The product np³ is the displaced volume (V_e) of an entanglement that is also expressible as pd or kT/G. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1768–1776, 2002     

Orthokinetic Aggregation in Two Dimensions of Monodisperse and Bidisperse Colloidal Systems

Orthokinetic aggregation of colloids trapped at the air–liquid interface was studied by direct imaging in a couette cell. This method allowed us to follow the temporal evolution of both the cluster-mass distribution and the cluster structure at a shear rate where Brownian aggregation is suppressed. The interactions between the monodisperse latex particles floating at the air–liquid interface were controlled either by varying the electrolyte concentration or by creating a bidisperse system through the addition of small particles. The results show that the clusters in all of the systems are characterized by a high fractal dimension, indicating that the clusters are rearranged and densified by the shear. Kinetic analysis suggests that aggregation of monodisperse systems mainly proceeds through homogeneous aggregation, i.e., large clusters sticking to other large clusters. The bidisperse system, finally, with a size ratio around 10, favored a more heterogeneous aggregation among small and large clusters throughout the aggregation process; a slightly lower fractal dimension was observed compared to the strongly aggregated monodisperse system.     

烟草三维荧光特征和品质评吸的关系

研究不同品种烟草石油醚冷萃取物的三维荧光光谱，包括烟草所共在的荧光性质和各自的荧光特性，寻找它们与烟草香味，颈头等吃味之间的关系，选择合适的量值指标，为烟草品质的 观感官评估提供了一个实用的对照方法。     

Closed‐form rectangular atomic wave functions of an N‐dimensional atom

A closed‐form expression has been derived to obtain the N‐dimensional rectangular atomic wave functions. The wave functions can be obtained straightforwardly with the knowledge of the angular momentum quantum numbers and the dimension and there is no need to employ recursive methods as in previous works. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 88: 263–274, 2002     

The dependence of sorbent/analyte type on observed differences in supercritical fluid extraction efficiencies employing extraction vessels of different dimensions

Summary The effect of extraction cell dimensions (i.d.: length) on supercritical fluid extraction (SFE) efficiencies of polychlorinated biphenyls (PCBs) is shown to be dependent on the type of sorbent used. For octadecylsilane (C18) sorbents, there is a significant increase in observed SFE recoveries of PCBs when the cell dimensions are made more broad (increased i.d.: length); whereas, no effect of cell geometry is observed when the common adsorbent, Florisil, is utilized. Additionally, recoveries decreased in proportion to the chlorine number, for the PCBs studied, for octadecylsilane sorbents, while no such effect was observed for Florisil. These results illustrate the magnitude of the matrix effect in SFE, which generally dominated observed recoveries, even in the simplest analyte/sorbent systems such as the one studied here.     

Metal ion distribution and solubility of Mn1−xCux(HCOO)2 · 2 H2O Mixed Crystals [1–5]

The metal ion distribution on the two metal sites of monoclinic Mn_1?xCu_x(HCOO)₂ · 2(H,D)₂O mixed crystals are studied by infrared and Raman spectroscopic methods. The spectral regions 3 200–3 400 cm^?1 (v_OH), 2 875–2 990 cm^?1 (v_CH), 2 330–2 500 cm^?1 (v_OD of matrix isolated HDO molecules), 1 350–1 400 cm^?1 (symmetric CO₂ stretching modes), 570–950 cm^?1 (H₂O librations), and 490 cm^?1 (M? O lattice modes) are mostly sensitive to the metal ions present. The frequency shifts of these bands with increasing content of copper show that Cu²⁺ prefers the M(1) site, coordinated by HCOO^? only. The strengths of the hydrogen bonds increase on going from manganese to copper formate, due to the increased synergetic effect of Cu²⁺. Solubility and X-ray data of the mixed crystals are included. Irrespective of the same crystal structure, two series of mixed crystals are formed: eutonic area at 0.65 ≥ x ≥ 0.5.     

二阶三点数值微分公式的外推算法

利用Taylor公式，给出了二阶三点数值微分公式在各点的截断误差的渐近展开式，并利用Richardson外推算法，提高二阶三点数值微分公式的收敛阶数，得到高精度的二阶数值微分公式．     

乙醇三维内微肋热管的传热性能

采用实验研究的方法对三维内微肋热管的强化传热特性进行研究，首次报道了以乙醇为工质的三维内微肋热管的传热性能。在实验范围内，与光管相比，竖直放置时，沸腾换热系数可以提高98％—190％，凝结换热系数可以提高76％—178％。三维内微肋结构能够同时明显地强化热管的沸腾换热与凝结换热，可以有效地减小热管的内热阻。