活性炭的Zeta电位对其吸附达旦黄规律的影响

The effect of pH on the adsorption of anionic dye Titan yellow on the activated carbon from aqueous solution has been studied. It has been found that the Zeta potential of the activated carbon has a great effect on adsorption capacity of Titan yellow. The kinetic and the thermodynamic parameters of adsorption as a function of pH has been evaluated. The mechanism for adsorption of anionic dye Titan yellow on the activated carbon has also been discussed.     

Viscoelastic response of elastomers in large deformations

A simple nonlinear theory of viscoelasticity has been developed for application to elastomers. The interpretation of nonlinear viscoelastic responses based on Gibbs-DiMarzio theory has been identified at a molecular level and hence structural understanding has been established. The introduced model is applied to strain imposed conditions. From this, a relaxation process has been revealed for the resultant stress, where a dependence of relaxation time on the state of strain has been established.     

Ionization probability of the hydrogen atom suddenly released from confinement

The problem of the stability of a confined atom when it is extracted from the confining cavity has been investigated, modeled by a spherical hard wall potential. The ionization probability when the atom is released from confinement has been obtained. The dependence of the ionization probability on the confinement radius and on the quantum numbers of the initial confined state has been studied. The probability density function of the ionization energy of the ejected electron has been obtained for the different cases considered. The oscillatory structure of this distribution function, with a principal maximum located in the neighborhood of the energy of the initial state and minima very close to zero has been elucidated. The sudden approximation has been applied and the analytic continuation method has been used to calculate the different stationary states.     

Influence of the heating rate on the temperature profiles and on the conversion rate of powdery cellulose and pine sawdust

An experimental study of the thermal decomposition of powdered cellulose and pine sawdust has been performed. The influence of the heating rate on the temperature profiles in the sample and on the solid conversion rate has been studied. A mathematical model without adjustable parameters has been used to calculate the temperature at different points in the solid bed and the average total solid conversion. The experimental results have been compared with those calculated by the model. A good agreement has been obtained for sawdust. Some differences are observed for cellulose at high heating rates, and the influence of the thermal conductivity and the reaction heat on the results has been analysed.     

Synthesis and microstructure-mechanical property relationships of segmented polyurethanes based on a PCL-PTHF-PCL block copolymer as soft segment

The goal of this work has been the synthesis of novel materials based on a biodegradable polycaprolactone-block-polytetrahydrofurane-block-polycaprolactone diol (PCL-b-PTHF-b-PCL). The segmented thermoplastic polyurethanes (STPU) have been synthesised in bulk without catalyst at different molar ratios and their characterization has been performed by different techniques. The physic-chemical interactions, responsible for the unique polyurethane properties, have been evaluated by total attenuated Fourier transform infrared spectroscopy (ATR-IR) in the amide I region using a Gaussian deconvolution technique and, on the other hand, atomic force microscopy (AFM) has been employed to determine the phase microstructures. The effect of increase the hard segment content (HS) has been discussed from the viewpoint of the miscibility of hard and soft segments, analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The influence of HS content on the microstructure-mechanical property relationships has also been investigated. Special attention has been focused on the wettability of the samples, measured through water contact angle measurements (WCA), to determine the tendency for biocompatibility of the samples.     

Synergism in the extraction of scandium

Synergism in the extraction of scandium by a mixture of di-2-ethylhexyl phosphoric acid and a β-diketone has been studied. The nature of the extracted species has been investigated. The effect of temperature on extraction has been studied and synergism has been explained on the basis of thermodynamic parameters of the extraction process.     

Theory and mechanism of electron transfer in a condensed medium at high temperatures with allowance for change in vibrational frequencies

An expression for electron transfer rate has been obtained through the solution of a time wave equation by the variational method by defining the wave function as a linear combination of functions corresponding to electron localization on the donor and on the acceptor. A dependence of electron transfer on temperature, on the electronic and vibrational characteristics of the system has been derived. An activation energy temperature-variation effect has been obtained. It has been proved that many-electron transfers are impossible.     

Investigation of the role of the C-PCM solvent effect in reactivity indices

It has been shown recently, how the coupling between electronic degrees of freedom and vibrational modes is reflected in the properties of molecules. The necessary derivatives have been analyzed and their thermodynamic relations were demonstrated. This present work is focused on the analysis of a molecular system, under the influence of C-PCM induced solvent effect. The analysis is based on reactivity indices derived from DFT. The shift of frequency for diatomic molecules has been obtained. It has been identified as chemical force effect. The role of nuclear reactivity indices has been emphasized. This concept has been extended to obtain regional chemical potential values within C-PCM model for polyatomic molecules.     

Fixed-bed adsorption of carbon dioxide/methane mixtures on silicalite pellets

The adsorption of carbon dioxide and methane on silicalite pellets packed on a fixed bed has been studied. Equilibrium and kinetic measurements of the adsorption of carbon dioxide and methane have been performed, and a binary adsorption isotherm for carbon dioxide/methane mixtures has been obtained. A model based on the LDF approximation for the mass transfer has been used to describe the breakthrough curves obtained experimentally. A PSA cycle has been proposed for obtaining methane with purity higher than 98% from carbon dioxide/methane mixtures containing 38% and 50% methane, and its performance has been simulated using the proposed model. The simulation results show that silicalite can be a suitable adsorbent for employment in a PSA separation process for carbon dioxide removal from coalseam and landfill gases.     

Photosensitivity,substituent and solvent-induced shifts in UV-visible absorption bands of naphthyl-ester liquid crystals: a comparative theoretical approach

The substituent- and solvent-induced shifts in UV-visible absorption bands of naphthyl-ester nematic liquid crystals, viz., 4-octylphenyl-6-octyloxy-2-naphthoate (NAPHE1) and 6-octyloxy-2-naphthylyl-4-octyloxybenzoate (NAPHE2), have been investigated using the DFT, CNDO/S and INDO/S methods. A correlation has been made between molecular charge distribution and phase stability based on Mulliken, Loewdin, AM1, PM3, MNDO, CNDO/S and INDO/S methods. The observed π→π* and n→π* electronic transitions have been reported. The substituent- and solvent-induced shifts in absorption bands, transition energies and energy gaps have been discussed. The photosensitivity of the molecules has been analysed based on these shifts. It has been observed that the substituent has a dominant role on both absorption maxima and energy band gap, whereas the solvent has a dominant role only on absorption maxima, and no effect has been observed on the energy gap. These shifts may provide beneficial consequences in determining the end use of compounds.     

Studying the Adsorption of an Iron(II) Complex of 1,10-Phenanthroline on Laboratory Glassware Using Thermal Lens Spectrometry

The adsorption of iron(II) tris(1,10-phenanthroline) on the glass surface of laboratory ware from solutions has been studied by thermal lens spectrometry at a level of nanogram amounts. The effect of glass pretreatment on the fraction of the adsorbed substance has been studied, and the most appropriate variant of the pretreatment has been selected. The kinetics of iron(II) tris(1,10-phenanthroline) adsorption on the surface of laboratory glass has been studied, and an adsorption isotherm has been constructed for nanogram chelate contents of the solution. The process is most closely approximated by the Freundlich equation. Based on the obtained data, a procedure has been proposed for the preparation of solutions for constructing calibration relationships that can be used in thermal lens measurements of trace amounts of analytes. This procedure takes into account the loss of substances at the surface of laboratory glassware.     

The influence of the concentration and size of silver nanoparticles on the conductivity of ring-shaped deposits resulting from evaporation of colloidal solution droplets

The conductivity of ring-shaped deposits formed at the periphery of evaporating droplets of silver nanoparticle colloidal solutions has been studied. The dependence of the resistance of the ring-shaped deposits on nanoparticle size has been shown to exhibit a percolation transition. The specific conductivity of the deposits has been estimated in relation to their geometric shapes. The conductivity has been established to nonmonotonically depend on nanoparticle sizes. It has been noted that, in rather strong fields, the conductivity of the composite layers dramatically increases after some induction period. The X-ray spectra of silver have been revealed to alter for samples the conductivity of which has increased under the action of an external electric field.     

Revert and direct type Liesegang phenomenon of silver iodide

The experimental conditions for Liesegang phenomenon of silver iodide in agar gel columns, and particularly the transition from revert to direct type of periodic precipitations, have been investigated. The theoretically derived Mathur's spacing law, which suits both revert and direct type of Liesegang's rings, has been experimentally verified. An attempt has been made to explain the mechanism of revert and direct type and of the transition of revert to direct type of periodic precipitation on the basis of adsorption on the precipitated silver iodide and of flocculation. The dependence of the transition point on the concentrations of the outer and inner electrolytes has been studied. The time law of Morse and Pierce has been verified. The dependence of the velocity constant ( ) on the concentrations of the outer and inner electrolytes has been studied.     

C~6~0^3^-的Jahn-Teller变形、电子结构和光谱性质的理论研究

本文用INDO系列方法对C~6~0^3^-进行了几何构型优化, 得到D~2~h构型, 表明C~6~0^3^-确实发生了Jahn-Teller变形, 导致单键变短, 双键变长, 其额外负电荷和单电子主要分布在赤道附近。以此构型为基础, 计算其电子吸收光谱, 与实验值基本吻合, 在对光谱进行理论指认的同时, 讨论了光谱红移的原因。     

Calculation of vapor mass flux upon isothermal condensation on spherical droplets in a wide range of Knudsen numbers based on the solution of the Boltzmann kinetic equation

Vapor mass flux density has been calculated on the surface of spherical droplets under almost isothermal conditions. The calculations have been performed at droplet radii corresponding to the free-molecular, intermediate, and continuum flow regimes. The study has been performed by the direct numerical solution of the Boltzmann kinetic equation. The method of characteristics has been adapted for describing transfer processes in spherically symmetric systems. The applicability of different simplified approaches to the calculation of mass flux density on droplet surface has been estimated.     

Functionalization of an amorphous ethylene-propylene copolymer by free radical initiated grafting of unsaturated molecules

Functionalization of an amorphous ethylene-propylene copolymer, EPM, has been performed by means of homogeneous grafting reactions of unsaturated molecules such as dibutylmaleate, diethylfumarate, itaconic anhydride, and maleic anhydride, initiated by free radicals. Dicumylperoxide and dibenzoylperoxide have been used as a free radical source and their efficiency has been compared. A different reactivity of the unsaturated molecules has been evidenced. The influence of the nature of the solvent on the functionalization degree has been investigated, revealing a noticeable effect of the solvent either on the amounts of grafted molecules or on the secondary reactions which lead to partial degradation of the functionalized EPM chains.     

Contactless Conductivity Detection in Capillary Electrophoresis: A Review

The popularity of contactless conductivity detection in capillary electrophoresis has been growing steadily over the last few years. Improvements have been made in the design of the detector in order to facilitate its handling, to allow easy incorporation into available instruments or to achieve higher sensitivity. The understanding of its fundamental working principles has been advanced and the detection approach has also been transferred to lab‐on‐chip devices. The range of applications has been extended greatly from the initial work on small inorganic ions to include organic species and biomolecules. Concurrent determination of cations and anions by dual injection from opposite ends has been demonstrated as well as sample introduction by using flow‐injection systems for easy automation of the process.     

113mIn radioisotope generator system

Tin-indium generator systems were made with commercial hydrated zirconium oxide, silica gel and hydrated zirconium oxide prepared by the AMPHLETT method. The adsorption capacity of tin has been determined by both spectrophotometric analysis and gammaspectrometry. Zirconium break-through has been determined and compared with the literature values. The dependence of the adsorption capacity on the particle size has been investigated. The effect of autoclaving on the generator systems has been examined.     

生物活性物质与光谱探针反应的研究-血清白蛋白与铬天青S的反应

本文研究了铬天青SL(CAS)与牛血清白蛋白(BSA)在酸性溶液中反应前后的吸收光谱,认为CAS 与BSA 主要通过静电引力而结合,研究发现这一探针反应不符合Scatchard模型,提出了处理此类体系溶液平衡的一个新的线性回归方程, 由此方程可以求算结合常数,最大结合数以及吸光系数等体系参数,最后考察了实验条件对结合反应的影响.