نتایج جستجو برای: polydispersity index

تعداد نتایج: 397231  

Journal: :علوم و تکنولوژی پلیمر 0
محمد سلطانیه احمد رمضانی سعادت آبادی علی دشتی جعفر مختاری

in this article, a complete model for the mixed flow slurry reactor for polymerization of ethylene to high density polyethylene in the presence of ziegler-natta catalyst is presented. in addition to the effects of the multiple active sites, the effect of other important parameters such as the catalyst concentration, co-catalyst, hydrogen, monomer, impurities and pressure on the mass-average and...

Journal: :Physical review letters 2005
Pinaki Chaudhuri Smarajit Karmakar Chandan Dasgupta H R Krishnamurthy A K Sood

The phase diagram of a polydisperse hard-sphere system is examined by numerical minimization of a discretized form of the Ramakrishnan-Yussouff free-energy functional. Crystalline and glassy local minima of the free energy are located and the phase diagram in the density-polydispersity plane is mapped out by comparing the free energies of different local minima. The crystalline phase disappears...

2016
Qaisra Naheed Choudhry Mi Jeong Kim Tae Gyun Kim Jeong Hoon Pan Jun Ho Kim Sung Jin Park Jin Hyup Lee Young Jun Kim

Our work aimed to investigate the protective effects of saponin-based nanoemulsions of vitamin A and E against oxidative stress-induced cellular damage in AML-12 cells. Saponin nanoemulsions of vitamin A (SAN) and vitamin E (SEN) were prepared by high-pressure homogenization and characterized in terms of size, zeta potential, and polydispersity index. SEN and SAN protect AML-12 cells against ox...

2015
Benjamin F. Strick Massimiliano Delferro Franz M. Geiger Regan J. Thomson

The ring-opening metathesis polymerization (ROMP) of apopinene is reported. We find that apopinene reacts with Rubased metathesis catalysts to provide an all trans-polymer with a polydispersity index (PDI) as low as 1.6 and molecular weights in the 1100 to 15 600 g·mol−1 range (9−127 monomer units). Because apopinene is readily prepared in one-step from myrtenal or two-steps from α-pinene, both...

Journal: :Organic & biomolecular chemistry 2006
Atsushi Ikeda Taishin Irisa Tomoe Hamano Toyokazu Kitahashi Yoshihiro Sasaki Mineo Hashizume Jun-Ichi Kikuchi Toshifumi Konishi Seiji Shinkai

A new molecular design of fullerene derivatives exhibiting trigger-responsive self-aggregation in organic solvents has been established. Calix[4]arene was covalently connected with fullerene in order to apply host-guest interaction to the aggregation control. The self-assembly behaviour was studied in organic solvents by UV-vis absorption spectroscopy, dynamic light scattering and transmission ...

Journal: :Physical review letters 2002
Yuri Martínez-Ratón José A Cuesta

The phase diagram of a polydisperse mixture of uniaxial rodlike and platelike hard parallelepipeds is determined for aspect ratios kappa=5 and 15. All particles have equal volume, and polydispersity is introduced in a highly symmetric way. The corresponding binary mixture is known to have a biaxial phase for kappa=15, but to be unstable against demixing into two uniaxial nematics for kappa=5. T...

Journal: :Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 1996
Bolhuis Kofke

We have established the solid-fluid coexistence region for a system of polydisperse hard spheres with near Gaussian diameter distributions, as a function of polydispersity. Our approach employs Monte Carlo simulation in the isobaric semigrand ensemble with a Gaussian activity distribution. Gibbs-Duhem integration is used to trace the coexistence pressure as a function of the variance of the imp...

2008
Yurij V. Kalyuzhnyi Peter T. Cummings

Abstract. A theoretical scheme for the calculation of the full phase diagram (including cloud and shadow curves, binodals and distribution functions of the coexisting phases) for colloidpolymer mixtures with polymer chain length polydispersity and hard-sphere colloidal and polymeric monomer sizes polydispersity is proposed. The scheme combines thermodynamic perturbation theory for associating f...

Journal: :Chemical communications 2015
Zachary S Kean Gregory R Gossweiler Tatiana B Kouznetsova Gihan B Hewage Stephen L Craig

Here we present a coumarin dimer (CD) mechanophore that, when embedded near the mid-chain of poly(methyl acrylate) polymers, activates under pulsed ultrasound conditions to yield coumarin chain-end functional polymers. Quantitative photochemical scission of the CD polymers provides a reference against which the activation efficiency of chain-centered mechanophores in polymers synthesized by con...

Journal: :Journal of physics. Condensed matter : an Institute of Physics journal 2014
Philip J Camp Ekaterina A Elfimova Alexey O Ivanov

The effects of particle-size polydispersity on the initial susceptibilities of concentrated ferrofluids are analyzed using a combination of theory and computer simulation. The study is focused on a model ferrofluid with a prescribed magnetic-core diameter distribution, a fixed non-magnetic surface layer (corresponding to a demagnetized layer and adsorbed surfactant) and a combination of dipolar...

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