•The AC treatment increased η% of the mixed self-assembled monolayer.•Organic molecules may be re-orientated in the alternating electric field.•The AC-treated effects depended on the AC-treated potential.•The AC-treated effects were caused by the formation of a complex compound.•The AC-treated effects were also caused by the reduction of the oxide film.The inhibitive effects of alternating current-treated (AC-treated) mixed self-assembled monolayer (SAMHL/DT) with 2-(Pyridin-2-yliminomethyl)-phenol (HL) and dodecanethiol (DT) on copper corrosion have been studied by using the scanning electrochemical microscope (SECM) combined with Tafel and electrochemical impedance spectroscopy (EIS) methods When the AC-treated potential is applied in the cathodic region, the inhibition efficiency increases, and the pitting dynamic processes are inhibited. All the results reveal that the AC-treated effects are related to both the formation of complex compounds and the reduction of the oxide film on the surface of copper.

•SECM was used to study current oscillations in the Fe│H2SO4 system.•A polyaniline-modified microelectrode was used to monitor pH at the interface.•A Pt microelectrode was used to monitor Fe2 + at the interface.•pH oscillations were observed at the interface during the current oscillations.•The oxide film plays a key role in the oscillations of the system.An unmodified Pt microelectrode and a Pt microelectrode coated with polyaniline were used in conjunction with a scanning electrochemical microscope (SECM) to study anodic dissolution in the Fe│H2SO4 system. The concentrations of Fe2 + (cFe2 +) measured with the unmodified microelectrode and the pH values measured with the polyaniline-modified microelectrode were recorded in situ during current oscillations in the Fe│H2SO4 system and were found to change periodically at the Fe│H2SO4 interface. The changes in cFe2 + may be caused by the periodic formation and dissolution of surface film(s), which could be salt films and/or oxide films. If a salt film is formed, it is unlikely to affect the pH. Since the pH changes periodically during the current oscillations, it can be deduced that the surface film is mainly composed of oxide, and that the formation and dissolution of the oxide film play a key role in the current oscillations of the system.

A facile base-mediated isocyanide-based three-component cycloaddition protocol for chemoselective formation of functionalized spiro-substituted furans and pyrroles derivatives has been developed. Fairly good yields of the products, the ready availability of the starting materials and the excellent chemoselectivity are the main advantages of this method.

A facile method has been developed for the preparation of densely functionalized tricyclic fused pyrimidine derivatives by three-component [3+2+1] cyclization. Fairly good yields of the products (up to 88%), the ready availability of the low-cost starting materials, the catalyst-free and mild conditions are the main advantages of this method.A facile three-component [3+2+1] cyclization protocol for the preparation of densely functionalized tricyclic fused pyrimidine derivatives has been designed.

In this paper, the magnetic field perturbation method is used to study the effects of the Lorentz force and the gradient magnetic force on the anodic dissolution of Ni in 0.50 mol dm-3 HNO3 + 5.0 mmol dm-3 NaCl solution. During the anodic dissolution process, magnetic fields are applied in two directions: parallel (B//) and perpendicular (B⊥) to the surface of the electrode. Thus, the effects of different magnetic forces on the anodic dissolution can be analyzed. After the application of B//, the current may increase, decrease or remain stable under different potentials, while the peak potential, the oscillatory region and the passive potential shift positively. These are always caused by the Lorentz force, which enhances the mass-transport processes. However, after the application of B⊥, the peak potential, the oscillatory region and the passive potential shift negatively. The currents always tend to decrease under the different potentials, which can be explained as follows: the gradient magnetic force suppresses convection to increase the concentration of corrosion products, such as the paramagnetic Ni(II) species, in local positions at the electrode|electrolyte interface. However, neither B// nor B⊥ affects the anodic dissolution in the passive region for the oxide film on the electrode surface inhibits the MF effects. If Ni dissolves in 0.50 mol dm-3 HNO3 with different chloride ions containing solution at the same potential, the effects caused by B// are different for it is in different regions and the rate-determining steps are different, however, the currents still tend to decrease with application of B⊥.

The perturbation method is used to study the way how the halide ions affect the anodic dissolution of the X70 electrode in 5.0 mol dm−3 H3PO4 solution. In different regions, the effects of the halide-ion perturbation are different. In the oscillatory region, the periodic current oscillations change to the irregular ones when a small amount of Cl− or Br− solution is injected at the electrode electrolyte interface. However, the oscillations are still periodic except the oscillatory frequency increases with the injection of F−. In the passive region, current oscillations are induced by the X− (X = Cl, Br, I) ions. It is clear that pitting is induced by the X− (X = Cl, Br) ions, in which Cl− is the most aggressive, followed by Br−. But the pitting induced by I− is not obvious in SEM micrographs. Only general corrosion is induced by the fluoride species. The results show that the way how the halide ions affect the anodic dissolution is related with the types of the ions and the property of the film formed on the surface of the electrode.