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61.
Aurelia Visa Nicoleta Plesu Bianca Maranescu Gheorghe Ilia Ana Borota Luminita Crisan 《Molecules (Basel, Switzerland)》2021,26(1)
The inhibition effect of N,N′-phosphonomethylglycine (PMG) and vinyl phosphonic acid (VPA) on the 3% NaCl acidic solution corrosion of carbon steel iron was studied at different immersion times by potentiodynamic polarization, electrochemical impedance spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and computational methods. It is found from the polarization studies that PMG and VPA behave as mixed-type inhibitors in NaCl. Values of charge transfer resistance (Rct) and double layer capacitance (Cdl) in the absence and presence of inhibitors are determined. The PMG and VPA inhibitors were capable of inhibiting the corrosion process up to ≈91% and ≈85%, respectively. In the presence of PMG, the synergic effect of chlorine ions was observed. Density functional theory (DFT) was engaged to establish the adsorption site of PMG, VPA, and their deprotonated states. For studied compounds, the resulted values of ELUMO, EHOMO, energy gap (∆E), dipole moment (μ), electronic hardness (η), global softness (σ), electrophilic index (ω), and the electronic potential map are in concordance with the experimental data results regarding their corrosion inhibition behavior and adsorption on the metal surface. 相似文献
62.
Errami J Peyrard M Theodorakopoulos N 《The European physical journal. E, Soft matter》2007,23(4):397-411
We report model calculations on DNA single strands which describe the equilibrium dynamics and kinetics of hairpin formation
and melting. Modeling is at the level of single bases. Strand rigidity is described in terms of simple polymer models; alternative
calculations performed using the freely rotating chain and the discrete Kratky-Porod models are reported. Stem formation is
modeled according to the Peyrard-Bishop-Dauxois Hamiltonian. The kinetics of opening and closing is described in terms of
a diffusion-controlled motion in an effective free-energy landscape. Melting profiles, dependence of melting temperature on
loop length, and kinetic time scales are in semiquantitative agreement with experimental data obtained from fluorescent DNA
beacons forming poly(T) loops. Variation in strand rigidity is not sufficient to account for the large activation enthalpy
of closing and the strong loop length dependence observed in hairpins forming poly(A) loops. Implications for modeling single
strands of DNA or RNA are discussed. 相似文献
63.
64.
Methods of automatic computer analyses of images have large impotence in numerous physical problems with different kinds of radiations, which use such solid-state detectors as nuclear photographic emulsions, plastics and others. We described a method of expanding boundaries of dark areas for such computer analyses of micro-pictures. We demonstrated effectiveness of this method by the example of the search of microcrystals size distributions in two undeveloped nuclear emulsions and similar distribution of background grains in the developed emulsion. 相似文献
65.
S. V. Nizhankovskyi A. V. Tan'ko N. S. Sidelnikova G. T. Adonkin 《Crystal Research and Technology》2015,50(3):223-229
It is shown that the formation of longitudinal aggregation of inclusions in bulk sapphire and yttrium‐aluminum garnet (YAG) grown by the method of HDC is caused by local accumulation of impurities, disturbance of morphological stability of the crystallization front and capture of inclusions and impurities in the nodal region of the melt two‐vortex convection. Studied is the influence of thermal and geometrical parameters of the melt and the shape of the crystallization front on the conditions of the formation of the capture of inclusions. 相似文献
66.
This study investigated the cooling crystallization of aluminum sulfate to explore the basic data for the recovery of aluminum resources from coal spoil. Cooling crystallization process of aluminum sulfate with sodium dodecylbenzenesulfonate (SDBS) was investigated experimentally. The effects of operating conditions, namely rotate speed and cooling rate on the crystal size (Median diameter, D0.5) were studied. Based on single factor experimental results, the response surface method (RSM) with a Box–Behnken design (BBD) was used to determine the key operating conditions, from which a predictive equation was established to quantitatively describe the relationships of D0.5 and there relative parameters. The optimum operating conditions for cooling crystallization of aluminum sulfate were as follows: rotate speed of 200–300 rpm, cooling rate of 4–5 °C /min and n (SDBS)/n (Al2(SO4)3) of around 5E‐4. Molecular dynamics (MD) results reveal that SDBS decreases the diffusion coefficient (D) of Al3+ molecules, which inhibits nucleation and promotes crystal growth. 相似文献
67.
计算机分子模拟在分子印迹技术中的应用 总被引:1,自引:0,他引:1
传统的分子印迹技术对模板分子、功能单体、交联剂、致孔剂等的筛选往往依靠经验,常通过反复实验对合成条件进行优化,存在实验周期长、耗材量大等问题。计算机分子模拟技术的应用在实验过程中起到可预见性指导作用,可以实现精准识别位点的裁制、识别驱动力的设计,通过结合能等物化特征参数计算优化识别体系的稳定性,从而合理选择模板分子、功能单体、交联剂、致孔剂,优化聚合条件,以提高聚合物识别特异性和亲和力,缩短实验周期,更符合绿色化学的理念。本文简单介绍了计算机分子模拟技术,重点对其在分子印迹技术中的指导作用进行了综述,并对其在分子印迹技术中的应用进行了展望。 相似文献
68.
69.
Tom Lowrie 《International Journal of Computers for Mathematical Learning》2002,7(3):301-318
This paper explores the way in which young children (6 year olds) made sense of screen-based images on the computer. The participants
were required to interpret 3D-like representations and relate these images to objects in their environment. Both static and
relatively dynamic software programs were used in the investigation. Some of the children could not make links between the
screen representation and the intended three-dimensional (3D) objects. It is argued that young children should be exposed
to activities that establish explicit links between 2D and 3D objects ``away' from the computer before attempting the more
difficult links required to interpret and represent 3D objects in ICT contexts.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
70.
本文讨论了概率约束规划目标函数的连续收敛性,并利用概率测度弱收敛的特征给出了概率约束规划可行集的收敛性条件,得到了概率约束规划逼近最优解集的上半收敛性. 相似文献