We study the existence and uniqueness of best proximity points for two classes of non-self-contractive mappings: almost (φ,θ)-contractive mappings and Meir–Keeler-type contractive mappings. 相似文献
A measurement method is proposed for the ultrasonic characterization of a fluid layer, corresponding to the resin transfer molding (RTM) manufacturing process. The ultrasonic velocity and attenuation of the silicone oil are measured in three samples having different viscosities. The measurement method is established on the basis of the attenuation of ultrasonic waves in fluids. A correction of the beam diffraction is implemented to improve measurement precision. A single element transducer with central frequency of 15 MHz is used. The tested fluids simulate the industrial resin used to manufacture composite materials. When injecting this resin, its viscosity increases until it reaches a critical state of polymerization. In this paper we focus on ultrasonic characterization of three fluids representing three intermediate cases of fluid resin during its injection before reaching the polymerization state. 相似文献
A novel peri-annulated heterocyclic system of 1,2-dihydrobenz[6,7]oxepino[4,3,2-cd]indole was prepared starting from TNT via 4,6-dinitro-1-tosylindoline as a key intermediate. Base-induced CC bond shift in 1,2-dihydrobenz[6,7]oxepino[4,3,2-cd]indoles affords isomeric 2,11-dihydrobenz[6,7]oxepino[4,3,2-cd]indoles. 相似文献
We present a second order self-consistent implicit/explicit (methods that use the combination of implicit and explicit discretizations are often referred to as IMEX (implicit/explicit) methods , and ) time integration technique for solving radiation hydrodynamics problems. The operators of the radiation hydrodynamics are splitted as such that the hydrodynamics equations are solved explicitly making use of the capability of well-understood explicit schemes. On the other hand, the radiation diffusion part is solved implicitly. The idea of the self-consistent IMEX method is to hybridize the implicit and explicit time discretizations in a nonlinearly consistent way to achieve second order time convergent calculations. In our self-consistent IMEX method, we solve the hydrodynamics equations inside the implicit block as part of the nonlinear function evaluation making use of the Jacobian-free Newton Krylov (JFNK) method , and . This is done to avoid order reductions in time convergence due to the operator splitting. We present results from several test calculations in order to validate the numerical order of our scheme. For each test, we have established second order time convergence. 相似文献
Phosphate washing waste (PWW) is one of the wastes generated by the phosphate mine with a very high amount. This waste was investigated in this work to study the effect of the calcination of the PWW at four different temperatures 600 °C, 700 °C, 800 °C and 900 °C on its mineralogical and chemical composition. The samples were investigated by X-ray powder diffraction, Fourier transform infrared, differential scanning calorimetry and thermogravimetric analysis, solid-state magic angle spinning nuclear magnetic resonance of 29Si, 27Al and 31P and scanning electron microscope. The results show that the PWW presents a complex system and it suffers a significant change on its mineralogical and chemical composition after calcination. It reveals the presence of carbonate, natural zeolite, fluorapatite, quartz and clay. After calcination, the waste shows the disappearance of some of these phases and the appearance of others and some other phases remain steady.
The crystal structure of 2-amino-5-benzoyl-4-(2-nitrophenyl)-3-cyano-4,5-dihydrothiophene is determined by X-ray diffraction
analysis. The unit cell parameters are as follows: a = 10.878(2) Å, b = 12.890(3) Å, c = 13.539(4) Å, α = 108.15(2)°, β = 99.26(2)°, γ = 107.13(2)°, V = 1656(2) Å3, dcalcd = 1.410 g/cm3, Z = 4, and space group P1ˉ. The molecules occupy two systems of independent positions in the crystal. Similar to the compounds studied earlier in
this series, the o-nitrophenyl substituent has a synperiplanar orientation relative to the hydrogen atom at the C(4) atom of the heterocycle.
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Translated from Kristallografiya, Vol. 45, No. 2, 2000, pp. 282–285.
Original Russian Text Copyright ? 2000 by Nesterov, Kuleshova, Samet, Shestopalov. 相似文献
In this paper, we establish certain fixed point theorems in metric spaces with a partial ordering. Presented theorems extend and generalize several existing results in the literature. As application, we use the fixed point theorems obtained in this paper to study existence and uniqueness of solutions for fourth-order two-point boundary value problems for elastic beam equations. 相似文献