Sorption phenomena of organic solvents in polymers: Part I

In this work we use the vapor-sorption equilibrium data to show the degree of solvent upturn in each solvent-polymer system. For this purpose, 23 isothermal data sets for four polymer + solvent binaries, one block copolymer + solvent binary and for the corresponding polymer pairs have been used in the temperature range of 25-70 °C. Solvents studied are benzene, carbon tetrachloride, chloroform and pentane. Homopolymers studied are polyisobutylene, poly(ε-caprolactone), poly(ethylene oxide), n-heptadecane, polystyrene, poly(vinyl chloride), poly(vinyl methyl ether), and n-tetracosane.According to these data sets, solvent weight fraction in the polymer is plotted against solvent-vapor activity that is calculated assuming an ideal gas phase of pure solvent vapor neglecting the vapor pressure of the polymer. We use the Flory-Huggins theory to obtain dimensionless interaction parameter, χ. Also the Zimm-Lundberg clustering theory and non-ideality thermodynamic factor, Γ are used to interpret the equilibrium data.     

Preparation of Ag nanoparticles termini‐protected side‐chain liquid crystalline azobenzene polymers by RAFT polymerization

A new synthetic approach to prepare Ag nanoparticles protected side‐chain liquid crystalline (LC) azobenzene polymers was reported. It is based on the reduction of silver ions in presence of a LC polymer polymerized by RAFT. The formation of Ag colloidal nanoparticles was confirmed by TEM and UV analysis. At the same time, according to the results of DSC, XPS, and FTIR spectra, Ag nanoparticles were protected by the side‐chain LC azobenzene polymers through surface attachment interactions between thiol groups and Ag. The out‐plane orientation of side‐chain LC is confirmed by surface‐enhanced Raman spectra analysis and scanning near‐field optical microscope, resulting from the large electromagnetic field arising from the excitation of surface plasmon polariton of Ag nanoparticles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5380–5386, 2007     

隐变量交互作用分析建模及其在SAS上的实现

探讨隐变量交互作用分析的建模方法及其在SA S软件上的实现;首先阐述隐变量交互作用分析建模的原理,通过拟合一个隐变量交互作用分析示例,对加入交互作用项的统计分析结果与无交互作用项的统计分析结果进行对比;示例中交互作用项引起的变异在结果变量的总变异中占到79.20%.在应用结构方程模型分析隐变量产生的效应时,有时候不进行隐变量交互作用的分析可能会产生偏倚.     

MARS: selecting basis functions and knots with an empirical Bayes method

An empirical Bayes method to select basis functions and knots in multivariate adaptive regression spline (MARS) is proposed, which takes both advantages of frequentist model selection approaches and Bayesian approaches. A penalized likelihood is maximized to estimate regression coefficients for selected basis functions, and an approximated marginal likelihood is maximized to select knots and variables involved in basis functions. Moreover, the Akaike Bayes information criterion (ABIC) is used to determine the number of basis functions. It is shown that the proposed method gives estimation of regression structure that is relatively parsimonious and more stable for some example data sets.     

17C反应截面测量及有限力程Glauber模型分析

用透射法测量了能量为79AMeV的¹⁷C在¹²C反应靶上的反应截面;利用有限力程Glauber模型对¹⁷C的密度分布进行了分析.由高能区(965AMeV)相互作用截面数据分析认为¹⁷C具有谐振子密度分布,但拟合本实验结果及高能区实验数据发现,¹⁷C的中子密度分布中存在一个尾巴;假设¹⁷C密度为芯核加单粒子密度分布形式,分析认为¹⁷C的价中子主要处于1d5/2?轨道.     

Characteristic Study of the Periodically Iris-Loaded Elliptical Waveguide for Slow-Wave Structures

The slow-wave characteristics taking no account of space harmonics for periodically iris-loaded elliptical waveguides is presented. By using the field-matching method, the dispersion equation and the mean interaction impedance for odd and even hybrid modes of this structure are derived respectively. It is indicated from the numerical calculation results that changing the eccentricity can improve the dispersion characteristics and the interaction impedance for _oHEM₀₁ mode.     

Superparamagnetic relaxation Mössbauer spectra by phonon–magnon interaction using the multilevel method

The formation of local moments and the effect of charge carrriers in dilute magnetic semiconductors can be well understood using local probe techniques like Mossbauer Spectroscopy. We report here on Mossbauer studies in the systems Fe_0.008Ge_{1 ? x} D _x (D = As, Bi), Fe_0.008Ge_{1 ? x} In _x , and Fe_0.008Ge_{1 ? x} Sn _x . At room temperature magnetic interactions were observed for donor (D) impurities at the Fe site in the Fe_0.008Ge system. No such magnetic ordering was observed for acceptor (In) or neutral (Sn) impurities.     

Spectral manifestation of the interaction of polyurethane components with oxide groups

The spectral-structural characteristics of polyurethane compositions with antipyrene fillers were investigated by a method of IR spectroscopy. The changes revealed in the vibrational spectra can be caused by intermolecular interaction of oligoether and diphenylmethane diisocyanate with aluminum-, boron-, and phosphor-containing compounds.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 133–135, January–February, 2005.     

Digestive process of the raptorial feeder ciliate Litonotus lamella (Rabdophora, Litostomatea) visualized by fluorescence microscopy

In this paper we present a fluorescence microscopy investigation of the digestive process of Litonotus lamella, which we used as a prototype of the raptorial feeding behaviour. The sequence of its digestive processes, from the capture of the prey (Euplotes crassus) to the formation of digestive vacuoles was evidenced using Acridine Orange, a high quantum yield fluorescent vital probe which has a great affinity with the acid vesicle compartments. Acid vesicle localization and displacement during digestion consisted of the following phases: in starved Litonotus vesicles were localized in the neck of the ciliate; after the capture, they were displaced around the vacoule containing the prey in early digestiion, whereas in advanced digestion tens of digestive vacuoles containing Euplotes fragments were spread over the body of the predator; 1 h after capture, the digestive process was complete, and acid vesicles reorganized in the neck of the predator. The most important feature we observed was that the digestive process occurred not in the single phagosome as in filter feeder ciliates, such as Paramecium, but in many digestive vacuoles scattered all over the predator cytoplasm, which asynchronously digest prey fragments.     

受扰动的光纤孤子间的相互作用

基于含扰动的非线性薛定谔方程，发展了高登的光孤子相互作用理论，直接从近似的二孤子解昨到描述实际光纤通讯中孤子间的相互作用的解析公式，公式表明在实际的通讯系统中光纤孤子间的相互作用不令依赖于它们之间相对相差，而且依赖于它们的相对能量，速度差随传输距离的变化。