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681.
BOUOIDINA Asmae EL-HAJJAJI Fadoua EMRAN Khadijanh BELGHITI Mohammed Elalaoui ELMELOUKY Abderrahmane TALEB Mustapha ABDELLAOUI Abdelfattah HAMMOUTI Belkheir OBOT Ime Bassey 《高等学校化学研究》2019,35(1):85-100
Today,due to the increasingly stringent European directives concerning the use of molecules with certain toxicities towards the environment or their users,the essential oils,extracts,and molecules derived from plants exhibiting the characteristic of being biodegradable can be considered as a source of green corrosion inhibitors instead of harmful synthetic chemicals.The present work was devoted to testing the essential oil extracted from Mentha pulegium leaves(M1) as a corrosion inhibitor for C-steel in 1mol/L HCl solution using both electrochemical techniques and gravimetric measurements for the evaluation of the inhibition efficiencies at different temperatures.The results obtained showed that the inhibition efficiency increased with an increase in Ml concentration to reach a maximum value of 92.21%.We sought to determine the molecule responsible for this high efficiency,starting with the analysis of oil chemical composition by gas chromatography coupled with mass spectrometry.This analysis revealed that menthol(M2)and isomenthol(M3)were the principal constituents.In order to identify the molecule responsible for the inhibition and explain the protection mechanism involved,quantum chemical calculations and Monte Carlo simulations were used to explain the interaction of menthol,the major constituent of M1 with the Fe-surface.To practically confirm these results,we studied the action of 1mol/L HCl on steel with and without the addition of M2 by both methods(gravimetric and electrochemical study).A very high efficiency was obtained,an efficiency of 94.90% at 10^-3 mol/L,which was retained for a long exposure time,and slightly decreased in function of temperature.Finally,a good correlation between the experimental data,theoretical calculations,and SEM studies was obtained,which denied that the Ml efficiency was only a result of a synergy effect and confirmed the high efficiency of Mentha oil and its main component(menthol)as a strong ecological inhibitor of corrosion. 相似文献
682.
针对非平衡态外推边界处理方法在某些条件下发生质量泄漏的问题,结合质量守恒定律对其进行修正,建立一种新的质量守恒型的边界处理格式.其基本思想是在边界处定义一个虚拟密度来修正平衡态分布函数,使得系统质量守恒.以重力作用下的密度场及磁流体模拟问题为例,利用该格式进行分析,讨论质量泄露问题的本质及各种因素的影响.通过对三种典型的流动:二维Poiseuille流、Couette流、Womersley流的模拟,验证该边界格式的计算精度和稳定性. 相似文献
683.
Multiple scattering of light by water cloud droplets with external and internal mixing of black carbon aerosols
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The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere(water cloud droplets containing black carbon(BC) inclusions),and the single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz-Mie theory.The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally.The multiple scattering characteristics are computed by using the Monte Carlo method.The results show that when the size of the BC aerosol is small,the reflection intensity of the internal mixing model is bigger than that of the external mixing model.However,if the size of the BC aerosol is big,the absorption of the internal mixing model will be larger than that of the external mixing model. 相似文献
684.
In this paper, we investigate the effect of unequal injection rates on totally asymmetric simple exclusion processes (TASEPs) with a 2-input 1-output junction and parallel update. A mean-field approach is developed to deal with the junction that connects two sub-chains and the single main chain. We obtain the stationary particle currents, density profiles and phase diagrams. Interestingly, we find that the number of stationary-state phases is changeable depending on the value of α1 (α1 is the injection rate on the first sub-chain). When α1 > 1/3, there are seven stationary-state phases in the system, however when α1< 1/3, only six stationary-state phases exist in the system. The theoretical calculations are shown to be in agreement with Monte Carlo simulations. 相似文献
685.
686.
We have studied the aggregation of particles on a hetero-substrate
consisting of two different substrates A and B with finite surface
barriers EAB and EBA between the AB and BA boundaries,
respectively. With the diffusion energy limited aggregation (DELA)
model, we find that the number of clusters and the mean radius of
gyration of the clusters are dependent on the surface barriers EAB and EBA. For the case with a constant of EBA, a series of minima are summarized as EAB= (E0- kBAEBA)/ kAB with kAB and kBA being two integers, for main minima (kBA=kAB-
1) and two local minima (kBA=kAB and kBA=kAB + 1) between two neighbouring main minima. 相似文献
687.
Monte Carlo simulations of biaxial structure in thin hybrid nematic film based upon spatially anisotropic pair potential
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Hybrid nematic films have been studied by Monte Carlo simulations
using a lattice spin model, in which the pair potential is spatially
anisotropic and dependent on elastic constants of liquid crystals.
We confirm in the thin hybrid nematic film the existence of a
biaxially nonbent structure and the structure transition from the
biaxial to the bent-director structure, which is similar to the
result obtained using the Lebwohl--Lasher model. However, the
step-like director's profile, characteristic for the biaxial
structure, is spatially asymmetric in the film because the pair
potential leads to K1 ≠ K3. We estimate the upper cell
thickness to be 69 spin layers, in which the biaxial structure can
be found. 相似文献
688.
This paper shows the calculations of radioactivity and afterheat
in the components of the China Spallation Neutron Source (CSNS) target
station, with the Monte Carlo codes LAHET, MCNP4C and the multigroup
code CINDER'90. These calculations provide essential data for the
detailed design and maintenance of the CSNS target station. 相似文献
689.
Inverse Monte Carlo study on effective interaction potential of Ag--Rh alloy from pair correlation functions
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This paper presents an inverse Monte Carlo method to
reconstruct pair interaction potential from pair correlation
function. This approach adopts an iterative algorithm on interaction
potential to fit known pair correlation function by compelling
deviations of canonical average to meet with Hamiltonian parameters
on a basis of statistical mechanism. The effective interaction
potential between particles in liquid Ag--Rh alloys has been
calculated with the inverse Monte Carlo method. It demonstrates an
effective and simple way to obtain the effective potential of
complex melt systems. 相似文献
690.