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81.
The purpose of this work is the continuum modelling of transport and pile-up of infinite discrete dislocation walls driven by non-local interaction and external loading. To this end, the underlying model for dislocation wall interaction is based on the non-singular Peierls–Nabarro (PN) model for the dislocation stress field. For simplicity, attention is restricted to walls consisting of single-sign dislocations and to continuous wall distributions on a single glide plane. In this context, the influence of strongly non-local (SNL; long-range) interaction, and its approximation as weakly non-local (WNL; short-range) are studied in the context of interaction- and external-load-driven wall pile-up at a boundary. The pile-up boundary is modelled via a spatially dependent dislocation mobility which decreases to zero at the boundary. The pile-up behaviour predicted by the current SNL-based continuous wall distribution modelling is consistent with that predicted by discrete wall distribution modelling. Both deviate substantially from the pile-up behaviour predicted by WNL-based continuous wall distribution modelling. As such, it is clearly essential to account in continuum models for the intrinsic SNL character of the interaction between same-sign dislocations ‘close’ to the boundary. Gradient-based WNL ‘approximation’ of this interaction is not justified. 相似文献
82.
Solvent‐free one‐pot synthesis of 2,2′‐dithioxo‐[5,5′]bithiazolidinylidene‐4,4′‐dione (birhodanine) derivatives from the reaction of primary amines and carbon disulfide in the presence of dimethyl acetylene dicarboxylate has been reported. 相似文献
83.
Attenuated total internal reflectance Fourier transform infrared, ATR-FTIR, spectroscopy was used to compare the water uptake and doping within polyelectrolyte multilayers made from poly(styrene sulfonate), PSS, and a polycation, either poly(allylamine hydrochloride), PAH, or poly(diallyldimethylammonium chloride), PDADMAC. Unlike PDADMA/PSS multilayers, whose water content depended on the solution ionic strength, PAH/PSS multilayers were resistant to doping by NaCl to a concentration of 1.2 M. Using (infrared active) perchlorate salt, the fraction of residual counterions in PDADMA/PSS and PAH/PSS was determined to be 3% and 6%, respectively. The free energy of association between the polymer segments, in the presence of NaClO4, was about 5 kJ mol-1 and -10 kJ mol-1, respectively, for PDADMA/PSS and PAH/PSS, indicating the relatively strong association between the polymer segments in the latter relative to the former. Varying the pH of the solution in contact with the PAH/PSS multilayer revealed a transition to a highly swollen state, interpreted to signal protonation of PAH under much more basic conditions than the pKa of the solution polymer. The increase in the multilayer pKa suggested an interaction energy for PAH/PSS in NaCl of ca. 16 kJ mol-1. 相似文献
84.
Esmaeilpour Mohsen Javidi Jaber Dodeji Fatemeh Nowroozi Zahmatkesh Saeed 《Research on Chemical Intermediates》2021,47(6):2629-2652
Research on Chemical Intermediates - A practical and green method for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones and 1H-pyrazolo[1,2-b]phthalazine-diones using Fe3O4@SiO2-imid-PMAn... 相似文献
85.
Asymptotic representations of solutions of one class of second-order ordinary differential equations
We establish asymptotic representations for some classes of solutions of nonautonomous second-order differential equations
close, in a certain sense, to linear equations. 相似文献
86.
Karg M Jaber S Hellweg T Mulvaney P 《Langmuir : the ACS journal of surfaces and colloids》2011,27(2):820-827
Highly uniform, core-shell microgels consisting of single gold nanoparticle cores and cross-linked poly-N-isopropylacrylamide (PNIPAM) shells were prepared by a novel, versatile protocol. The synthetic pathway allows control over the polymer shell thickness and its swelling behavior. The core-shell structure was investigated by electron microscopy and atomic force microscopy, whereas the swelling behavior of the shell was studied by means of dynamic light scattering and UV-vis spectroscopy. Furthermore, the latter method was used to investigate the optical properties of the hybrid particles. By modeling the scattering contribution from the PNIPAM shells, the absorption spectra of the gold nanoparticle cores could be recovered. This allows the particle concentration to be determined, and this in turn permits the calculation of the molar mass of the hybrid particles as well as the refractive index of the shells. 相似文献
87.
Jiang D Burrows AD Jaber R Edler KJ 《Chemical communications (Cambridge, England)》2012,48(41):4965-4967
A facile in situ nanoparticle seeding method is reported to prepare MIL-101(Cr) films on alumina supports. The in situ seeding of MIL-101(Cr) nanoparticles was promoted by use of dimethylacetamide (DMA). The generality of this approach is further demonstrated for Cu(3)(btc)(2) films by using a (poly)acrylate promoter. 相似文献
88.
Nasiri R Field MJ Zahedi M Moosavi-Movahedi AA 《The journal of physical chemistry. A》2012,116(11):2986-2996
We report a comprehensive density functional theory (DFT) study of the mechanism of pentosidine formation. This work is a continuation of our earlier studies in which we proposed pathways for formation of glucosepane (J. Mol. Model. 2011, pp 1-15, DOI 10.1007/s00894-011-1161-x), GODIC (glyoxal-derived imidazolium cross-link), and MODIC (methyl glyoxal-derived imidazolium cross-link; J. Phys. Chem. 2011, 115, pp 13542-13555). Here we show that formation of pentosidine via reaction of α-oxoaldehydes with lysine and arginine in aqueous solution is possible thermodynamically and kinetically, in good agreement with the available experimental evidence. Five pathways, A-E, were characterized, as in our previous GODIC and MODIC work. In pathways A and B, a Schiff base is first formed from lysine and methyl glyoxal (MGO), and this is followed by addition of arginine and glyoxal (GO). By contrast, in pathways C, D, and E, addition of arginine to MGO occurs first, resulting in the formation of imidazolone, which then reacts with lysine and GO to give pentosidine. Our calculations show that the reaction process is highly exergonic and that the three pathways A, C, and E are competitive. These results serve to underline the potentially important role that α-oxoaldehydes play as precursors in pentosidine formation in the complex field of glycation. 相似文献
89.
Dysprosium carbonates nanoparticles were synthesized by the reaction of dysprosium acetate and NaHCO3 by a sonochemical method. Dysprosium oxide nanoparticles with average size about 17 nm were prepared from calcination of Dy2(CO3)3·1.7H2O nanoparticles. Dy(OH)3 nanotubes were synthesized by sonication of Dy(OAC)3·6H2O and N2H4. The as-synthesized nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). Photoluminescence measurement shows that the nanoparticles have two emission peaks around 17,540 cm?1 and 20,700 cm?1, which should come from the electron transition from 4F9/2 → 6H15/2 levels and 4F9/2 → 6H13/2 levels, respectively. The effect of calcination temperature and sonication time was investigated on the morphology and particle size of the products. The sizes could be controlled by the feeding rate of the precipitating agent (NaHCO3 and N2H4) and slower feeding rate lead to smaller nanoparticles. 相似文献
90.
Sivan Louzoun‐Zada Qais Z. Jaber Micha Fridman 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15730-15740
The ratio between the dose of drug required for optimal efficacy and the dose that causes toxicity is referred to as the therapeutic window. This ratio can be increased by directing the drug to the diseased tissue or pathogenic cell. For drugs targeting fungi and malignant cells, the therapeutic window can be further improved by increasing the resolution of drug delivery to the specific organelle that harbors the drug's target. Organelle targeting is challenging and is, therefore, an under‐exploited strategy. Here we provide an overview of recent advances in control of the subcellular distribution of small molecules with the focus on chemical modifications. Highlighted are recent examples of active and passive organelle‐specific targeting by incorporation of organelle‐directing molecular determinants or by chemical modifications of the pharmacophore. The outstanding potential that lies in the development of organelle‐specific drugs is becoming increasingly apparent. 相似文献