Molecular deposition filming flooding (MDFF) is a novel oil recovery technique based on the thermopositive monolayer electrostatic adsorption of the MDFF agent on different interfaces within reservoir systems. In this...Molecular deposition filming flooding (MDFF) is a novel oil recovery technique based on the thermopositive monolayer electrostatic adsorption of the MDFF agent on different interfaces within reservoir systems. In this paper, the adsorption property of the MDFF agent, MD-1, on quartz sand has been studied through adsorption experiments at different pH and temperatures. Experimental data are also analyzed kinetically and thermodynamically. The results show that the adsorption of MD-1 on quartz sand takes place mainly because of electrostatic interactions, which corresponds to adsorption that increases with pH. Kinetic analyses show that at a higher pH the activation energy for adsorption gets lower and, therefore, the adsorption becomes quicker for MD-1 on quartz sand. Thermodynamic analyses show that pH plays an important role in the adsorption of MD-1 on quartz sand. At a higher pH, more negative surface charges result in the increase of electrostatic interactions between MD-1 and quartz sand. Therefore, the saturated adsorption amount increases and more adsorption heat will be released.展开更多
An overview of the advances in studies on tribology of molecular deposition （MD） films is presented here to summarize the studies of nanofrictional properties, adhesion, wear and mechanical behavior, as well as the ...An overview of the advances in studies on tribology of molecular deposition （MD） films is presented here to summarize the studies of nanofrictional properties, adhesion, wear and mechanical behavior, as well as the molecular dynamics simulation of nanotribological properties of the film in the last decade. Some key research topics which need to be investigate further are addressed.展开更多
Two nanomechanical properties of the moleculor deposition （ MD ） film deposited on the Au substrate were studied. The first is its nanotribological property investigated by an atomic force microscope, which indicate...Two nanomechanical properties of the moleculor deposition （ MD ） film deposited on the Au substrate were studied. The first is its nanotribological property investigated by an atomic force microscope, which indicates that the deposition of the MD film could reduce the frictional force. The second is its nanoindent property studied by a nano-indenter. The results show that, after the MD film is deposited on the Au substrate , the elastic modulus, hardness and load decreased all, moreover, the elastic deformation increased and the plastic deformation decreased, which indicates that the MD film can improve the nanomechanical properties of the Au substrate.展开更多
The physical vapour deposition of Ni atoms on α-Fe（001） surface under different deposition temperatures were simulated by molecular dynamics to study the intermixing and microstructure of the interracial region. Th...The physical vapour deposition of Ni atoms on α-Fe（001） surface under different deposition temperatures were simulated by molecular dynamics to study the intermixing and microstructure of the interracial region. The results indicate that Ni atoms hardly penetrate into Fe substrate while Fe atoms easily diffuse into Ni deposition layers. The thickness of the intermixing region is temperature-dependent, with high temperatures yielding larger thicknesses. The deposited layers are mainly composed of amorphous phase due to the abnormal deposition behaviour of Ni and Fe. In the deposited Ni-rich phase, the relatively stable metallic compound B2 structured FeNi is found under high deposition temperature conditions.展开更多
The result of UV-Vis adsorbance indicates that phthalocyanine copper cation and anion monolayers are alternately deposited, and dimmer is the major form. Through analyzing the 20th phthalocyanine MD film AFM image, we...The result of UV-Vis adsorbance indicates that phthalocyanine copper cation and anion monolayers are alternately deposited, and dimmer is the major form. Through analyzing the 20th phthalocyanine MD film AFM image, we know that the surface of MD film is flat and compact. The physical-chemical properties of molecular end-group have influence on the MD films surface character notably. The contact angles of water on the odd and even layer MD films vary greatly complying with "odd-even" regularity, and the value increases slightly with the increment of MD film layers due to the decrease of van der Waals force reinforced by substrate through MD films.展开更多
文摘Molecular deposition filming flooding (MDFF) is a novel oil recovery technique based on the thermopositive monolayer electrostatic adsorption of the MDFF agent on different interfaces within reservoir systems. In this paper, the adsorption property of the MDFF agent, MD-1, on quartz sand has been studied through adsorption experiments at different pH and temperatures. Experimental data are also analyzed kinetically and thermodynamically. The results show that the adsorption of MD-1 on quartz sand takes place mainly because of electrostatic interactions, which corresponds to adsorption that increases with pH. Kinetic analyses show that at a higher pH the activation energy for adsorption gets lower and, therefore, the adsorption becomes quicker for MD-1 on quartz sand. Thermodynamic analyses show that pH plays an important role in the adsorption of MD-1 on quartz sand. At a higher pH, more negative surface charges result in the increase of electrostatic interactions between MD-1 and quartz sand. Therefore, the saturated adsorption amount increases and more adsorption heat will be released.
基金the National Natural Science Foundation of China(Grant No.50575171)the National Basic Research Program of China(Grant No.2007CB607604)the Open Financial Fund of the State Key Laboratory of Tribology of Tsinghua University(Grant No.SKLT05-02).
文摘An overview of the advances in studies on tribology of molecular deposition （MD） films is presented here to summarize the studies of nanofrictional properties, adhesion, wear and mechanical behavior, as well as the molecular dynamics simulation of nanotribological properties of the film in the last decade. Some key research topics which need to be investigate further are addressed.
文摘Two nanomechanical properties of the moleculor deposition （ MD ） film deposited on the Au substrate were studied. The first is its nanotribological property investigated by an atomic force microscope, which indicates that the deposition of the MD film could reduce the frictional force. The second is its nanoindent property studied by a nano-indenter. The results show that, after the MD film is deposited on the Au substrate , the elastic modulus, hardness and load decreased all, moreover, the elastic deformation increased and the plastic deformation decreased, which indicates that the MD film can improve the nanomechanical properties of the Au substrate.
基金Project supported by the National Natural Science Foundation for Young Scientists of China (Grant No. 10702058)the China Postdoctoral Science Foundation (Grant No. 20090451100)
文摘The physical vapour deposition of Ni atoms on α-Fe（001） surface under different deposition temperatures were simulated by molecular dynamics to study the intermixing and microstructure of the interracial region. The results indicate that Ni atoms hardly penetrate into Fe substrate while Fe atoms easily diffuse into Ni deposition layers. The thickness of the intermixing region is temperature-dependent, with high temperatures yielding larger thicknesses. The deposited layers are mainly composed of amorphous phase due to the abnormal deposition behaviour of Ni and Fe. In the deposited Ni-rich phase, the relatively stable metallic compound B2 structured FeNi is found under high deposition temperature conditions.
文摘The result of UV-Vis adsorbance indicates that phthalocyanine copper cation and anion monolayers are alternately deposited, and dimmer is the major form. Through analyzing the 20th phthalocyanine MD film AFM image, we know that the surface of MD film is flat and compact. The physical-chemical properties of molecular end-group have influence on the MD films surface character notably. The contact angles of water on the odd and even layer MD films vary greatly complying with "odd-even" regularity, and the value increases slightly with the increment of MD film layers due to the decrease of van der Waals force reinforced by substrate through MD films.
