The goal of this article is to discuss the Simple Equations Method (SEsM) for obtaining exact solutions of nonlinear partial differential equations and to show that several well-known methods for obtaining exact solutions of such equations are connected to SEsM. In more detail, we show that the Hirota method is connected to a particular case of SEsM for a specific form of the function from Step 2 of SEsM and for simple equations of the kinds of differential equations for exponential functions. We illustrate this particular case of SEsM by obtaining the three- soliton solution of the Korteweg-de Vries equation, two-soliton solution of the nonlinear Schrödinger equation, and the soliton solution of the Ishimori equation for the spin dynamics of ferromagnetic materials. Then we show that a particular case of SEsM can be used in order to reproduce the methodology of the inverse scattering transform method for the case of the Burgers equation and Korteweg-de Vries equation. This particular case is connected to use of a specific case of Step 2 of SEsM. This step is connected to: (i) representation of the solution of the solved nonlinear partial differential equation as expansion as power series containing powers of a “small” parameter ; (ii) solving the differential equations arising from this representation by means of Fourier series, and (iii) transition from the obtained solution for small values of to solution for arbitrary finite values of . Finally, we show that the much-used homogeneous balance method, extended homogeneous balance method, auxiliary equation method, Jacobi elliptic function expansion method, F-expansion method, modified simple equation method, trial function method and first integral method are connected to particular cases of SEsM. 相似文献
The effects of pH,contact time and natural organic ligands on radionuclide Eu(Ⅲ) adsorption and mechanism on titanate nanotubes(TNTs) are studied by a combination of batch and extended X-ray absorption fine structure(EXAFS) techniques.Macroscopic measurements show that the adsorption is ionic strength dependent at pH < 6.0,but ionic strength independent at pH > 6.0.The presence of humic acid(HA) /fulvic acid(FA) increases Eu(Ⅲ) adsorption on TNTs at low pH,but reduces Eu(Ⅲ) adsorption at high pH.The results of EXAFS analysis indicate that Eu(Ⅲ) adsorption on TNTs is dominated by outer-sphere surface complexation at pH < 6.0,whereas by inner-sphere surface complexation at pH > 6.0.At pH < 6.0,Eu(Ⅲ) consists of ~ 9 O atoms at REu?O ≈ 2.40 in the first coordination sphere,and a decrease in NEu-O with increasing pH indicates the introduction of more asymmetry in the first sphere of adsorbed Eu(Ⅲ).At long contact time or high pH values,the Eu(Ⅲ) consists of ~2 Eu at REu-Eu ≈ 3.60 and ~ 1 Ti at REu-Ti ≈ 4.40 ,indicating the formation of inner-sphere surface complexation,surface precipitation or surface polymers.Surface adsorbed HA/FA on TNTs modifies the species of adsorbed Eu(Ⅲ) as well as the local atomic structures of adsorbed Eu(Ⅲ) on HA/FA-TNT hybrids.Adsorbed Eu(Ⅲ) on HA/FA-TNT hybrids forms both ligand-bridging ternary surface complexes(Eu-HA/FA-TNTs) as well as surface complexes in which Eu(Ⅲ) remains directly bound to TNT surface hydroxyl groups(i.e.,binary Eu-TNTs or Eu-bridging ternary surface complexes(HA/FA-Eu-TNTs)).The findings in this work are important to describe Eu(Ⅲ) interaction with nanomaterials at molecular level and will help to improve the understanding of Eu(Ⅲ) physicochemical behavior in the natural environment. 相似文献
Encapsulation and luminescence studies of [Ir(ppy)2(bpy)]Cl (ppy=2‐phenylpyridinate, bpy=2,2′‐bipyridine) within a hexameric resorcinarene capsule are reported. One IrIII complex cation was encapsulated within the capsule, as demonstrated by NMR and dynamic light scattering (DLS) studies. The emission color of the IrIII complex was drastically changed from orange to yellow by encapsulation, in contrast with the lack of significant changes in the absorption spectrum. The hexameric capsule effectively hampers the non‐radiative pathway to increase both the luminescence quantum yield and the exited state lifetime. The luminescent properties of the encapsulated IrIII complex depend on the ratio of IrIII complex to the resorcinarene monomer as well as the concentration of resorcinarene monomer owing to the reversible process of self‐assembly of the hexameric capsule. Quenching experiments revealed that the IrIII complex in the capsule was effectively separated from quenchers. 相似文献
Kinetic and product studies of the solvolyses of acyclic phosphorochloridates are extended to two cyclic diesters, 2-chloro-1,3,2-dioxaphospholane-2-oxide (1) and 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane-2-oxide (2). Slightly faster solvolyses are observed for 1 than for the acyclic dimethyl phosphorochloridate (3), and 2 solvolyzes somewhat slower than 3. An extended Grunwald–Winstein equation treatment shows similar sensitivities to changes in solvent nucleophilicity and solvent ionizing power for 1, 2, and 3, and a concerted SN2 attack is proposed in each case. Product studies for the solvolyses of 2 in aqueous alcohols are presented. 相似文献
Isocyanate-terminated prepolymers were synthesized using poly(tetramethylene oxide)glycol of molecular weight 1000 (PTMG1000) with tolylene-2,4-diisocyanate (TDI). The prepolymers were chain extended with N-methyldiethanolamine (N-MDEA) to form polyurethanes containing tertiary nitrogen. These polyurethanes were crosslinked with bromine terminated polyurethane, poly(urethane-imide), and poly(urethane-siloxane) through the formation of cationomers at tertiary nitrogen sites across the backbone polyurethanes. The crosslinked cationomeric polyurethanes were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), mechanical analyses, (static and dynamic), and static contact angles measurements. FTIR spectral studies confirms the formation of bromine terminated poly(urethane-imide) and poly(urethane-siloxane), as well as quaternization of the tertiary nitrogen which leads to crosslinking. A comparison of thermal stabilities of crosslinked polymers with respect to the chemical nature of bromine terminated prepolymers (BTP) indicates improved thermal stability for poly(urethane-imide) based ABCP. Stress-strain analysis shows high elongation values for poly(urethane-siloxane) and poly(urethane-imide) based ABCPs. Dynamic mechanical analysis reveals better damping for poly(urethane- siloxane) based AB crosslinked polymers. 相似文献
Reaction calorimetry is a very useful tool to monitor exothermic polymerization reactions as it is based on the estimation of the heat generated by the reaction. The objective of this work is to analyze the performance of an unscented Kalman filter (UKF) for online monitoring of batch vinyl acetate emulsion polymerization reactions. Reactions are performed in isoperibolic and isothermal conditions. The UKF is compared to an extended Kalman filter that has a very poor performance. The results show that the UKF is able to provide good estimates for the conversion, for the reactor and jacket temperatures, for the overall heat transfer coefficient between the reaction medium and the jacket, and for the heat loss from the jacket to the surroundings.