The effects of relative humidity (RH) on a printed circuit board finished with electroless nickel immersion gold (PCB-ENIG) under an adsorbed thin electrolyte layer (ATEL) were investigated in situ via the measurement...The effects of relative humidity (RH) on a printed circuit board finished with electroless nickel immersion gold (PCB-ENIG) under an adsorbed thin electrolyte layer (ATEL) were investigated in situ via the measurement of cathodic polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to clearly elaborate the corrosion behavior of PCB-ENIG in the atmospheric environment. Results indicated that the cathodic process of PCB-ENIG under ATEL was dominated by the reduction of dissolved oxygen, corrosion products, and H2O. The cathodic current density of PCB-ENIG increased progressively with increasing RH. Moreover, its cathodic current density in the solution was greater than that under ATEL. This result demonstrated that the diffusion process was not the controlling step during the limiting reduction of cathodic oxygen. When the polarization potentials were located in a more negative region, the cathodic polarization current density gradually decreased under 75% and 85% RH. Notably, the anodic process became the controlling step in the extremely thin liquid film during the remainder of the experiment.展开更多
In modern chemical engineering processes, the involvement of solid/fluid interface is the most important component of process intensification techniques, such as confined membrane separation and catalysis. In the revi...In modern chemical engineering processes, the involvement of solid/fluid interface is the most important component of process intensification techniques, such as confined membrane separation and catalysis. In the review, we summarized the research progress of the latest theoretical and experimental works to elucidate the contribution of interface to the fluid properties and structures at nano-and micro-scale. We mainly focused on water, alcohol aqueous solution, and ionic liquids, because they are classical systems in interfacial science and/or widely involved in the industrialization process. Surface-induced fluids were observed in all reviewed systems and played a critical role in physicochemical properties and structures of outside fluid. It can even be regarded as a new interface, when the adsorption layer has a strong interaction with the solid surface. Finally, we proposed a perspective on scientific challenges in the modern chemical engineering processes and outlined future prospects.展开更多
Corrosion at the taper/trunnion interface of total hip replacement(THR)often results in severe complications.However,the underlying mechanisms of biotribocorrosion at the taper/trunnion interface during the long-term ...Corrosion at the taper/trunnion interface of total hip replacement(THR)often results in severe complications.However,the underlying mechanisms of biotribocorrosion at the taper/trunnion interface during the long-term walking gait cycles remain to be fully understood.In this study,a hip joint simulator was therefore instrumented with an electrochemical cell for in-situ monitoring of the tribocorrosion evolution in a metal-on-polyethylene(MoP)THR during a typical long-term walking gait.In addition,the biotribocorrosion mechanism was investigated via surface and chemical characterizations.The experimental results confirmed that the taper/trunnion interface dominated the contemporary MoP hip joint corrosion.Three cyclic variations in the open circuit potential(OCP)were observed throughout the long-term electrochemical measurements,attributed to the formation and disruption of the adsorbed protein layer.The corrosion exhibited an initial increase at each period,peaking at approximately 0.125 million cycles,followed by a subsequent gradual reduction.Surface and chemical analyses revealed the formation of a tribochemical reaction layer(tribolayer)on the worn surface of the taper/trunnion interface.The surface/chemical characterizations and the electrochemical measurements indicated that the adhesion force of the adsorbed protein layer was weaker than that of the tribolayer.In contrast,the opposite was true for the corrosion resistance.Based on the observations from this study,the tribocorrosion mechanism of the taper/trunnion interface under the long-term walking gait cycles is deduced.展开更多
The effects of surface adsorption of bovine serum albumin(BSA) and human gamma-globulin(HGG) on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation(QCM-D),...The effects of surface adsorption of bovine serum albumin(BSA) and human gamma-globulin(HGG) on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation(QCM-D), a ball-on-disk reciprocating tribometer, and a three-electrode electrochemical cell. The results showed that the wear depth in the BSA solution was higher than that in the HGG solution. In the HGG solution, the HGG-adsorbed layer could act as a lubricating layer and protect the DLC film from wear. The wear volume of DLC film in BSA and HGG mixture solution was higher than that in single HGG solution. This may be because the BSA molecules inhibit the formation of HGG adsorbed layer during sliding.展开更多
The repassivation behavior of the single crystal of 321 stainless steel in room temperature solution of 3.5% MgC1_2 has been studied by the rapid scratching technique under potentiostatic conditions. The process of th...The repassivation behavior of the single crystal of 321 stainless steel in room temperature solution of 3.5% MgC1_2 has been studied by the rapid scratching technique under potentiostatic conditions. The process of the formation of the oxide film on the bare surface of the single crystal has been found in three steps: the formation of an adsorbed layer on fresh surface within～2.5 ms., the transformation of the adsorbed layer into an oxide film within～3 ms, and the growth of the oxide film. The kinetics of the adsorbed layer formation follows approximately the empirical rule: i(ι)=I^0exp(—at) with I^0 and a being constants. The kinetics of the oxide film growth may be expressed by i(ι)=J^0exp(—bt) with J^0 and b being constants. The rate of film growth is controlled by high-field ion conduction: i=Aexp(—BV/X). The current density up to 1100 mA/cm^2 on the bare surface has been observed.展开更多
The dehydration of water by dimethyl carbonate(DMC)is of great significance for its application in electrochemistry and oil industry.With the rapid development of nanomaterial,one-dimensional(e.g.carbon nanotube(CNT))...The dehydration of water by dimethyl carbonate(DMC)is of great significance for its application in electrochemistry and oil industry.With the rapid development of nanomaterial,one-dimensional(e.g.carbon nanotube(CNT))and two-dimensional(e.g.lamellar graphene)materials have been widely used for molecular sieving.In this work,the molecular behavior of dimethyl carbonate/water mixture confined in CNT with varying diameters was studied based on molecular dynamics simulation.Due to different van der Waals interactions for the components in the mixtures with the solid surface,DMC molecules are preferentially adsorbed on the inner surface of the pore wall and formed an adsorption layer.Comparing with the pure water molecules confined in CNT,the adsorption DMC layer shows notable effect on the local compositions and microstructures of water molecules under nanoconfinement,which may result in different water mobility.Our analysis shows that the surface-induced DMC molecules can destroy the hydrogen bonding network of water molecules and result in an uniform and dispersed distribution of water molecules in the tube.These clear molecular understandings can be useful in material design for membrane separation.展开更多
基金Project(51271032)supported by the National Natural Science Foundation of ChinaProject(2014CB643300)supported by the National Basic Research Program of ChinaProject supported by the National Environmental Corrosion Platform,China
文摘The effects of relative humidity (RH) on a printed circuit board finished with electroless nickel immersion gold (PCB-ENIG) under an adsorbed thin electrolyte layer (ATEL) were investigated in situ via the measurement of cathodic polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to clearly elaborate the corrosion behavior of PCB-ENIG in the atmospheric environment. Results indicated that the cathodic process of PCB-ENIG under ATEL was dominated by the reduction of dissolved oxygen, corrosion products, and H2O. The cathodic current density of PCB-ENIG increased progressively with increasing RH. Moreover, its cathodic current density in the solution was greater than that under ATEL. This result demonstrated that the diffusion process was not the controlling step during the limiting reduction of cathodic oxygen. When the polarization potentials were located in a more negative region, the cathodic polarization current density gradually decreased under 75% and 85% RH. Notably, the anodic process became the controlling step in the extremely thin liquid film during the remainder of the experiment.
基金supported by the National Natural Science Foundation of China [21878144, 21729601, 21838004]the Foundation for Innovative Research Groups of the National Natural Science Foundation of China [21921006]+3 种基金Project of Jiangsu Natural Science Foundation of China [BK20171464]Project of Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the Kempe Foundation in Swedengrant of Ministry of Research and Innovation, CNCS-UEFISCDI, Romania, project number PN-III-P4-ID-PCCF-2016-0050, within PNCDI III and the Swedish Science Council (VR)。
文摘In modern chemical engineering processes, the involvement of solid/fluid interface is the most important component of process intensification techniques, such as confined membrane separation and catalysis. In the review, we summarized the research progress of the latest theoretical and experimental works to elucidate the contribution of interface to the fluid properties and structures at nano-and micro-scale. We mainly focused on water, alcohol aqueous solution, and ionic liquids, because they are classical systems in interfacial science and/or widely involved in the industrialization process. Surface-induced fluids were observed in all reviewed systems and played a critical role in physicochemical properties and structures of outside fluid. It can even be regarded as a new interface, when the adsorption layer has a strong interaction with the solid surface. Finally, we proposed a perspective on scientific challenges in the modern chemical engineering processes and outlined future prospects.
基金supported by the National Natural Science Foundation of China(52035012)the Science and Technology Planning Project of Sichuan Province(2020YJ0032)the 111 Project(B20008).
文摘Corrosion at the taper/trunnion interface of total hip replacement(THR)often results in severe complications.However,the underlying mechanisms of biotribocorrosion at the taper/trunnion interface during the long-term walking gait cycles remain to be fully understood.In this study,a hip joint simulator was therefore instrumented with an electrochemical cell for in-situ monitoring of the tribocorrosion evolution in a metal-on-polyethylene(MoP)THR during a typical long-term walking gait.In addition,the biotribocorrosion mechanism was investigated via surface and chemical characterizations.The experimental results confirmed that the taper/trunnion interface dominated the contemporary MoP hip joint corrosion.Three cyclic variations in the open circuit potential(OCP)were observed throughout the long-term electrochemical measurements,attributed to the formation and disruption of the adsorbed protein layer.The corrosion exhibited an initial increase at each period,peaking at approximately 0.125 million cycles,followed by a subsequent gradual reduction.Surface and chemical analyses revealed the formation of a tribochemical reaction layer(tribolayer)on the worn surface of the taper/trunnion interface.The surface/chemical characterizations and the electrochemical measurements indicated that the adhesion force of the adsorbed protein layer was weaker than that of the tribolayer.In contrast,the opposite was true for the corrosion resistance.Based on the observations from this study,the tribocorrosion mechanism of the taper/trunnion interface under the long-term walking gait cycles is deduced.
基金Funded by the National Natural Science Foundation of China(No.31570958)Science and Technology Support Program of Sichuan Province(No.2016SZ0007)
文摘The effects of surface adsorption of bovine serum albumin(BSA) and human gamma-globulin(HGG) on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation(QCM-D), a ball-on-disk reciprocating tribometer, and a three-electrode electrochemical cell. The results showed that the wear depth in the BSA solution was higher than that in the HGG solution. In the HGG solution, the HGG-adsorbed layer could act as a lubricating layer and protect the DLC film from wear. The wear volume of DLC film in BSA and HGG mixture solution was higher than that in single HGG solution. This may be because the BSA molecules inhibit the formation of HGG adsorbed layer during sliding.
基金Project supported by the National Natural Science Foundation of China.
文摘The repassivation behavior of the single crystal of 321 stainless steel in room temperature solution of 3.5% MgC1_2 has been studied by the rapid scratching technique under potentiostatic conditions. The process of the formation of the oxide film on the bare surface of the single crystal has been found in three steps: the formation of an adsorbed layer on fresh surface within～2.5 ms., the transformation of the adsorbed layer into an oxide film within～3 ms, and the growth of the oxide film. The kinetics of the adsorbed layer formation follows approximately the empirical rule: i(ι)=I^0exp(—at) with I^0 and a being constants. The kinetics of the oxide film growth may be expressed by i(ι)=J^0exp(—bt) with J^0 and b being constants. The rate of film growth is controlled by high-field ion conduction: i=Aexp(—BV/X). The current density up to 1100 mA/cm^2 on the bare surface has been observed.
基金supported by the National Science Foundation of China(21878144,21729601 and 21838004)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(21921006)+3 种基金Project of Jiangsu Natural Science Foundation of China(BK20171464)Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Kempe Foundation in Swedena grant of Ministry of Research and Innovation,CNCS-UEFISCDI,project number PN-III-P4-ID-PCCF-2016-0050,within PNCDI III and the Swedish Science Council(VR)。
文摘The dehydration of water by dimethyl carbonate(DMC)is of great significance for its application in electrochemistry and oil industry.With the rapid development of nanomaterial,one-dimensional(e.g.carbon nanotube(CNT))and two-dimensional(e.g.lamellar graphene)materials have been widely used for molecular sieving.In this work,the molecular behavior of dimethyl carbonate/water mixture confined in CNT with varying diameters was studied based on molecular dynamics simulation.Due to different van der Waals interactions for the components in the mixtures with the solid surface,DMC molecules are preferentially adsorbed on the inner surface of the pore wall and formed an adsorption layer.Comparing with the pure water molecules confined in CNT,the adsorption DMC layer shows notable effect on the local compositions and microstructures of water molecules under nanoconfinement,which may result in different water mobility.Our analysis shows that the surface-induced DMC molecules can destroy the hydrogen bonding network of water molecules and result in an uniform and dispersed distribution of water molecules in the tube.These clear molecular understandings can be useful in material design for membrane separation.
