Diffusion study of multi-organic layers in OLEDs by ToF-SIMS

A model organic light-emitting diodes (OLEDs) with structure of tris(8-hydroxyquinoline) aluminum (Alq₃)/N,N′-diphenyl-N,N′-bis[1-naphthy-(1,1′-diphenyl)]-4,4′-diamine (NPB)/indium tin oxide (ITO)-coated glass was fabricated for diffusion study by ToF-SIMS. The results demonstrate that ToF-SIMS is capable of delineating the structure of multi-organic layers in OLEDs and providing specific molecular information to aid deciphering the diffusion phenomena. Upon heat treatment, the solidity or hardness of the device was reduced. Complicated chemical reaction might occur at the NPB/ITO interface and results in the formation of a buffer layer, which terminates the upper diffusion of ions from underlying ITO.     

A neutral gas model for electron swarms

A BGK-type Boltzmann equation for a neutral gas is considered as a model for electron swarms, because the gas and the electron Boltzmann equation have a common diffusion approximation. Both full- and half-range theory are developed using orthogonality methods of solution. Preliminary comparisons with diffusion theory are presented.     

Ar—Kr溶液扩散系数的分子动力学模拟及其与温度的关系

用分子动力学模拟方法研究确定Ａｒ－Ｋｒ溶液的自扩散系数Ｄ１、Ｄ２和互扩散系数Ｄ１２以及它们随温度变化的规律。结果表明，分别用Ｇｒｅｅｎ－Ｋｕｂｏ法和Ｅｉｎｓｔｅｉｎ法得到的扩散系数在数值上一致；该溶液的３种扩散系数均满足Ｄ＝Ｄ０ｅ＾Ｅ／ＲＴ关系。     

原位漫反射红外光谱研究氮氧化物在Ag-ZSM-5催化剂上的吸附态及选择性催化还原反应机理

利用原位分析方法对催化剂表面吸附态进行动态表征，对了解催化反应机理具有重要的意义。漫反射红外光谱是一种理想的原位方法，应用该方法在298－773K范围原位考察了以丙烯为还原剂，NO在Ag-ZSM-5催化剂上的吸附态及选择性催化还原过程。认为NO的选择性催化还原符合直接作用机理，还原的关键是形成有机－氮氧化物（R－NO2或R－ONO）中间体。O2的作用是使C3H6充分活化，并是有效产生有机－氮氧化物不可缺少的条件。     

近红外漫反射光谱法对固态样品的无损分析

本文应用目标因子分析研究了固态样品的近红外漫反射光谱，用目标因子分析成功地确定了固态样品的物种数、物种种类和各物种的含量。     

Averaged molecular weight of complex mixtures as determined by rapid measurements of diffusion

Summary The concept of a diffusion-averaged molecular weight, M_d is presented, and M_d is defined for polydisperse samples. It is shown via oligostyrene mixtures that M_d can be determined in 20 minutes with common chromatographic equipment. If M_d is measured and M_n or M_w is known, the polydispersity can be obtained.     

Direct measurement of gas solubility and diffusivity in poly(vinylidene fluoride) with a high-pressure microbalance

We present solubility and diffusion data for the gases methane and carbon dioxide in the polymer poly(vinylidene fluoride). The polymer was cut from extruded piping intended for use in offshore oil and gas applications. Measurements were carried out using a purpose-built high-pressure microbalance. These properties were determined in the temperature range 80-120 °C and in the pressure range 50-150 bar for methane and 20-40 bar for carbon dioxide. In general, good agreement was obtained for similar measurements reported in the literature. Solubility follows a Henry’s law (linear) dependence with pressure. Diffusion coefficients for each of the gases in the polymer were also measured using the balance. Activation energies for diffusion and heats of solution for the two gases in the polymer were also determined.     

Transport properties of alkyltrimethylammonium bromide surfactants in aqueous solutions

Differential mutual diffusion coefficients of n-alkyltrimethylammonium bromides [CH₃(CH₂)_n–1N(CH₃)₃Br, C_nTAB] (n=10, 12, 14, 16) have been measured in aqueous solutions at 298.15 K using a conductimetric cell and an automatic apparatus to follow diffusion. The cell is based on an open-ended capillary, and the technique follows the diffusion process by measuring the resistance of a solution inside the capillaries at various times. The electrical conductances of those solutions have also been measured to calculate the critical micellar concentration (cmc). Thermodynamic analysis of the data suggests that the free ion concentration decreases at concentrations above the cmc, in agreement with theoretical predictions. The obtained values of the micellization parameters were used to model the mutual diffusion coefficients of C_nTAB aqueous solutions.     

聚氨酯(PU)/聚乙烯醇(PVA)共混体系的有关性能及其模型研究

本文研究了聚氨酯(PU)-聚乙烯醇(PVA)共混体系的动态力学性质、相逆转现象和透气性能.发现当PVA重量含量为30-50％时,共混体系发生了连续相与分散相的逆转.进一步,通过力学模型描述了该共混体系的模量-组成关系、动态力学温度谱以及透气系数与PVA含量的关系曲线.所有实验数据都落在理论预测的范围内,并分别与改进的Kerner模型和组合Kerner模型相符合.     

聚丙烯微孔膜基渐变聚合物的制备,结构与性能的研究

以聚丙烯微孔膜为基材，通过扩散控制原位共聚合的方法在人填充了组成沿膜的厚度方向逐渐改变的无规共聚物，Ｘ－光电子能谱（ＸＰＳ）、全反射红外光谱（ＡＴＲ）以及动态粘弹谱的分析结果。说明所制备得到的合膜具有明显的渐变聚合物性质。