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41.
M. Khairul Alam 《Aerosol science and technology》2013,47(1):41-52
An analysis is carried out to determine the combined effect of van der Waals and viscous fluid forces on coagulation of spherical aerosol particles in the free molecular, transition, and continuum regimes. The effect of viscous forces is taken into account by modifying the particle diffusion coefficient. An asymptotic solution is substituted for the classical formulation of viscous forces. The results of free molecular and continuum regimes are then extended to the transition size range by an interpolation formula. 相似文献
42.
M. F. Mina M. N. K. Chowdhury A. K. M. M. Alam G. H. Michler 《Polymer-Plastics Technology and Engineering》2013,52(2):217-222
The deformation behavior of rubber-toughened polymer, which was prepared by incorporating soft, core-shell rubbery particles into a glassy polymer such as poly (methyl methacrylate) (PMMA), has been investigated by means of mechanical tests, optical monitoring (OM), and scanning electron microscopy (SEM). By mechanical testing, the neat PMMA reveals a 2% strain with high yield stress. After inclusion of 17.5 and 35 vol%rubber particles, the softened-PMMA samples exhibit corresponding strain of 20% and 38%, showing an increase of strain along with the relative decrease of yield stress, resulting in a toughening behavior of PMMA. Clear shear bands and stress whitening develop in the rubber-toughened PMMA after deformation, as observed by OM. Investigation by SEM shows crazes/cracks in the stretched, rubber-softened PMMA samples in which the core-shell particles are found to be cavitated. The mechanism of this deformation has been explained based on the void formation in the rubbery shell as well as the initiation and propagation of crazing. 相似文献
43.
Zeid A. AlOthman Mohammad Mezbaul Alam Mu. Naushad 《Journal of Industrial and Engineering Chemistry》2013,19(3):956-960
Nernst–Planck equation was applied to study the heavy metal ion exchange kinetics over the surface of nylon 6,6 Zr(IV) phosphate at various temperatures under particle diffusion controlled phenomena. Various useful ion exchange kinetic parameters such as self-diffusion coefficient (Do), energy of activation (Ea), and entropy of activation (ΔS*) were evaluated to validate the ion exchange process for practical applicability of this composite cation exchanger in remediation processes of the environment. This study is also supported for the good selectivity of Cu(II) to validate the practical application of this cation exchanger in environmental analysis. 相似文献
44.
Todd M. Alam Joshua U. Otaigbe Dave Rhoades Gregory P. Holland Brian R. Cherry Paul G. Kotula 《Polymer》2005,46(26):12468-12479
Nanostructured polymer blends prepared via anionic ring opening polymerizations of cyclic monomers in the presence of a pre-made polymer melt exhibit a number of special properties over traditional polymer blends and homopolymers. Here, we report on a simple and versatile method of in situ polymerization of macrocyclic carbonates in the presence of a maleic anhydride polypropylene (mPP) matrix and a surface-active compatibilizer (i.e. PC grafted onto a mPP backbone generated in situ) to yield a micro- and nanostructured polymer blends consisting of a polycarbonate (PC) minor phase, and a polypropylene (PP) major phase. By varying the processing conditions and concentration of the macrocyclic carbonate it was possible to reduce the size of the PC dispersions to an average minor diameter of 150 nm. NMR and TEM characterizations indicate that the PC dispersions do not influence crystal content in the PP phase. Overall, the results point to a simple strategy and versatile route to new polymeric materials with enhanced benefits. 相似文献
45.
Lennard Karsten Nils Janson Vadim Le Joncour Sarfaraz Alam Benjamin Müller Jayendrakishore Tanjore Ramanathan Pirjo Laakkonen Norbert Sewald Kristian M. Müller 《International journal of molecular sciences》2022,23(5)
Epidermal growth factor receptor (EGFR) is a validated tumor marker overexpressed in various cancers such as squamous cell carcinoma (SSC) of the head and neck and gliomas. We constructed protein-drug conjugates based on the anti-EGFR Designed Ankyrin Repeat Protein (DARPin) E01, and compared the bivalent DARPin dimer (DD1) and a DARPin-Fc (DFc) to the monomeric DARPin (DM) and the antibody derived scFv425-Fc (scFvFc) in cell culture and a mouse model. The modular conjugation system, which was successfully applied for the preparation of protein-drug and -dye conjugates, uses bio-orthogonal protein-aldehyde generation by the formylglycine-generating enzyme (FGE). The generated carbonyl moiety is addressed by a bifunctional linker with a pyrazolone for a tandem Knoevenagel reaction and an azide for strain-promoted azide-alkyne cycloaddition (SPAAC). The latter reaction with a PEGylated linker containing a dibenzocyclooctyne (DBCO) for SPAAC and monomethyl auristatin E (MMAE) as the toxin provided the stable conjugates DD1-MMAE (drug-antibody ratio, DAR = 2.0) and DFc-MMAE (DAR = 4.0) with sub-nanomolar cytotoxicity against the human squamous carcinoma derived A431 cells. In vivo imaging of Alexa Fluor 647-dye conjugates in A431-xenografted mice bearing subcutaneous tumors as the SCC model revealed unspecific binding of bivalent DARPins to the ubiquitously expressed EGFR. Tumor-targeting was verified 6 h post-injection solely for DD1 and scFvFc. The total of four administrations of 6.5 mg/kg DD1-MMAE or DFc-MMAE twice weekly did not cause any sequela in mice. MMAE conjugates showed no significant anti-tumor efficacy in vivo, but a trend towards increased necrotic areas (p = 0.2213) was observed for the DD1-MMAE (n = 5). 相似文献
46.
Modeling of hydrogen vacancy for dissociative adsorption of H2 on Pd (1 1 1) surface by a quantum chemical molecular dynamics 总被引:1,自引:0,他引:1
47.
Novel nanocomposites of barium hexaferrite‐ and fullerene‐containing polyurethane were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X‐ray diffractometry, and energy‐dispersive X‐ray diffraction. The nanoparticles showed good dispersion in the polyurethane matrix. Their thermal, mechanical, and electromagnetic absorbance properties were studied. The complex permeability and permittivity were measured in the frequency range of 8.2–12.4 GHz. The maximum reflection loss of the nanocomposites was found to increase with increasing the ferrite content from 1% to 5%, with maximum value of −7.5 dB at only 5% composition. The incorporation of nanofiller not only imparts mechanical strength to the nanocomposite but also shows good radar‐absorbing properties at only 5% filler concentration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
48.
Positron annihilation lifetime spectroscopy and Doppler-broadened annihilation radiation (DBAR) experiments were performed on polypropylene-polystyrene (PP-PS) alloys (0-100% styrene) prepared by in situ polymerisation of styrene in a PP host matrix. The mean size of free-volume holes estimated from the ortho-positronium lifetime τ3 shows a continuous decrease from 0.119 nm3 in PP to 0.095 nm3 in PS. The intensity of the o-Ps component, I3, the average positron lifetime τav, the curve-shape parameter S and the peak height H of the DBAR spectra increase linearly with the styrene concentration. This is attributed to a linear superposition of the Ps yields of PP and PS in the PP-PS alloys. The DBAR spectra were fitted by a sum of three Gaussians, the narrowest of them is attributed to self-annihilation of para-positronium confined within holes. After its subtraction, a ‘broad component’ is obtained which represents the momentum distribution of electrons bound to molecules. Its normalised peak height does not show any change with the composition which reflects the fact that both constituents of the PP-PS alloys contain only hydrogen and carbon atoms in their chemical units. Immersing of PP into styrene liquid leads to a very pronounced increases in the lifetime parameters which is attributed to the plasticisation of PP. 相似文献
49.
Virgin olive oil (VOO) based polyetheramide (PEtA) was developed from N-N′-bis(2-hydroxyl ethyl) olive fatty amide (HEOA) and orcinol through condensation polymerization. PEtA was further treated with toluylene 2,4-diisocynate (TDI) with different percentages (20–30 wt%) via addition polymerization to obtain poly(ether amide urethane) (PEtAU). The structural elucidation of HEOA, PEtA and PEtAU were carried out by FT-IR, 1H NMR and 13C NMR spectroscopic techniques. Physico-chemical and physico-mechanical properties of the material were investigated by standard methods. Thermal stability and curing behavior of virgin olive oil, HEOA, and PEtAU were assessed by thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The corrosion behavior was investigated by potentiodynamic polarization measurements in different corrosive environments (3.5 wt% HCl, 5 wt% NaCl, 3.5 wt% NaOH, tap water) at room temperature. The results showed that UPEtA coatings exhibit good physico-mechanical as well as corrosion resistance performance and can be safely used up to 200 °C. The work is an attempt for alternate utilization of olive oil. 相似文献
50.
Bhogal Sangeeta Sharma Gaurav Kumar Amit Sharma Shweta Naushad Mu. Alam Manawwer Stadler Florian J. 《Topics in Catalysis》2020,63(11-14):1272-1285
Topics in Catalysis - In the present study, Ag2O–Al2O3–ZrO2 based trimetallic oxide nanocatalyst was designed using simple microwave assisted reduction method. It was characterized... 相似文献