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101.
102.
There is much enthusiasm now-a-days for efforts to improve membrane performances. Membrane modification is one of the critical approaches needed for the development of membrane science and technology. The beauty of research in this orientation is that it is a dynamic process that moves forward slowly and recommendations are made based on the science available. In this regard sulfonation of polysulfones is an excellent move. The present review demonstrates different sulfonation strategies of polysulfones as well as promoting applications in pressure driven separation sciences (viz. salt, macromolecule, organic separation from water). It shows that marked path is promising one. 相似文献
103.
104.
A.A. Al-Arfaj 《Physics and Chemistry of Liquids》2019,57(1):19-36
Excess quantities calculated from literature values of experimental density and viscosity in 1,2-dimethoxyethane + water binary systems (from 303.15 to 323.15 K) can lead us to test different correlation equations as well as their corresponding derivative properties. Inspection of the Arrhenius activation energy (Ea) and the enthalpy of activation of viscous flow (ΔH*) shows very close values; here, we can define partial molar activation energies Ea1 and Ea2 for 1,2-dimethoxyethane and water, respectively, along with their individual contribution separately. Correlation between the two Arrhenius parameters of viscosity in all compositions shows existence of main distinct interaction behaviours delimited by particular mole fractions in 1,2-dimethoxyethane. Moreover, we add that correlation between Arrhenius parameters reveals interesting Arrhenius temperature which is closely related to the vapourisation temperature in the liquid vapour equilibrium, and the limiting corresponding partial molar properties can permit us to estimate the boiling points of the pure components. 相似文献
105.
Decheng Wan Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》1999,37(15):2755-2761
The copolymerization of N-phenylmaleimide (NPMI) with ethyl phenylacrylate (EPA) in a mixture of dioxane (DIO) and pyridine (Py) was investigated. The apparent monomer reactivity ratio r1 (NPMI) = 0.07 ± 0.01 and r2 (EPA) = 0.09 ± 0.02 in DIO was turned to r1 (NPMI) = 3.67 ± 0.07 and r2 (EPA) = 0 ± 0.03 in Py. The copolymerization of NPMI and EPA with the fixed feed ratio (mol/mol 1 : 1) in different volume ratio of DIO/Py showed that the copolymer composition might be varied in a wide range from the 93.5% of NPMI contents in copolymer to 48.7%. When the volume fraction of Py in the mixture of DIO and Py was <10%, the copolymer with nice alternating structure was obtained and the copolymerization could be inhibited completely by hydroquinone; if the fraction of Py was >10%, the following two kinds of copolymers were formed: a copolymer in which the content of NPMI increased with the Py and the copolymerization also could be inhibited by hydroquinone and a copolymer with low molecular weight almost completely composed of homopolymer of NPMI and is not affected by radical inhibitor as hydroquinone. The transformation of the copolymerization mechanism from the radical to anionic, which was dependent on the volume ratio of DIO and Py, was suggested. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2755–2761, 1999 相似文献
106.
B. S. Narwade P. G. Gawali Rekha Pande G. M. Kalamse 《Journal of Chemical Sciences》2005,117(6):673-676
Dielectric constant (ε’) and dielectric loss (ε") of n-propyl alcohol (PA), ethylenediamine (EDA) and their binary mixtures,
for different mole fractions of ethylenediamine have been experimentally measured at 11.15 GHz microwave frequency. Values
of density (ρ), viscosity (η) and square refractive index (n
D
2
) of binary mixtures as well as those of pure liquids are reported. Excess square refractive index, viscosity and activation
energy of viscous flow have also been estimated. These parameters have been used to explain the formation of complexes in
the system. 相似文献
107.
The adsorption of a surfactant mixture, based on an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS) and a nonionic
surfactant (Triton X-100, or TX100), on alumina nanoparticles was determined by solution depletion method combined with spectrometric
measurement. It is shown that the light scattering, originated from the residual adsorbent alumina particles in the supernatant
after centrifugation separation, interferes with the measurements of absorbance of the surfactant molecules, and therefore
constitutes an error source for determination of the surfactant concentration in the supernatant by spectrometric means. The
intensity of this light scattering, namely the influence of the residual alumina nanoparticles upon the surfactant adsorption,
was related to the surfactant adsorption and its equilibrium concentration and varied among a batch. In this paper we report
a Kalman filter method in order to eliminate the variational scattering background caused by non-separated residual alumina
nanoparticles in each supernatant. This method is of interest as it is simple, easy to carry out and of high precision. 相似文献
108.
Yuriy K. Tovbin 《Adsorption》2005,11(3-4):245-257
The equilibrium distribution and the concentration dependence of the local and average self-diffusion coefficients for pure
fluid and binary mixture components in narrow slitlike pores were analyzed. The coefficients were calculated using the lattice
gas model in the quasi-chemical approximation on the assumption of a spherical shape and approximately equal sizes of the
components. For the pure adsorbate, these calculations were compared with molecular dynamics simulations. Both methods gave
similar concentration profile changes and dynamic characteristics of interlayer particle redistributions in strong nonuniform
adsorption fields for dense fluids. A satisfactory agreement was obtained for the temperature dependences of the self-diffusion
coefficients along the pore axis. The influence of the molecule–wall potential and of intermolecular interaction were considered.
The self-diffusion coefficients of the adsorbate were shown to strongly depend on the density of the mixture and the distance
from pore walls. 相似文献
109.
A capillary electrophoresis (CE) with UV absorption detection method is described for the simultaneous determination of glufosinate, glyphosate, and aminomethylphosphoric acid. The 9‐fluorenylmethyl chloroformate (FMOC‐Cl) was used for precolumn derivatization of the non‐absorbing herbicides. The three analytes were separated by CE in 9 min with 25 mM borate buffer at pH 9, followed by detection with a UV detector at 260 nm. We demonstrate how the detection limit can be enhanced by using acetonitrile‐salt mixtures. With acetonitrile‐salt mixtures, the limit of detection (LOD) was in the 10?7 M range. Linearity of more than two orders of magnitude was generally obtained. Precisions of migration times and peak areas were less than 0.9% and 7.5%, respectively. The applicabilities of the method for the analysis of ground water and lake water were examined. 相似文献
110.
以食品发热包为主题情境,通过探析发热包成分、解密发热原理、计算原料配比、配制发热包等环节梳理酸和碱的性质、用途。从元素观、转化观的视角认识物质转化规律,体现物质研究的一般思路,凸显科学探究的基本过程。通过设计方案测定发热包中碳酸钠的含量,总结混合物成分鉴定及定量测定的方法;归纳气体定量测定的影响因素。呈现一堂学科观念、学科方法教学具体课例,凸显物质研究、定性检验、定量测定的基本方法。 相似文献