Gas hydrates have drawn global attentions in the past decades as potential energy resources.It should be noted that there are a variety of possible applications of hydrate-based technologies,including natural gas stor...Gas hydrates have drawn global attentions in the past decades as potential energy resources.It should be noted that there are a variety of possible applications of hydrate-based technologies,including natural gas storage,gas transportation,separation of gas mixture,and seawater desalination.These applications have been critically challenged by insufficient understanding of hydrate formation kinetics.In this work,the literatures on growth kinetic behaviors of hydrate formation from water-hydrocarbon were systematically reviewed.The hydrate crystal growth,hydrate film growth and macroscopic hydrate formation in water system were reviewed,respectively.Firstly,the hydrate crystal growth was analyzed with respect to different positions,such as gas/liquid interface,liquid–liquid interface and gas–liquid–liquid system.Secondly,experimental and modeling studies on the growth of hydrate film at the interfaces between guest phase and water phase were categorized into two groups of lateral growth and thickening growth considering the differences in growth rates.Thirdly,we summarized the promoters and inhibitors reported(biological or chemical,liquid or solid and hydrophobic or hydrophilic)and analyzed the mechanisms affecting hydrate formation in bulk water system.Knowledge gaps and suggestions for further studies on hydrate formation kinetic behaviors are presented.展开更多
The surface oxide layer of grain-oriented electrical steels was investigated by scanning electron microscopy.The formation mechanism and the influence on the glass film of the surface oxide layer were analyzed by the ...The surface oxide layer of grain-oriented electrical steels was investigated by scanning electron microscopy.The formation mechanism and the influence on the glass film of the surface oxide layer were analyzed by the calculation of thermodynamics and kinetics.The surface oxide layer with 2.3μm in thickness is mainly composed of SiO_(2),a small amount of FeO and Fe_(2)SiO_(4).During the formation of surface oxide layer,the restriction factor was the diffusion of O in the oxide layer.At the initial stage of the decarburization annealing,FeO would be formed on the surface layer.SiO_(2) and silicate particles rapidly nucleated,grew and formed a granular oxide layer in the subsurface.As the oxidation layer thickens,the nucleation of new particles decreases,and the growth of oxide particles would be dominant.A lamellar oxide layer was formed between the surface oxide layer and the steel matrix,and eventually formed a typical three-layer structure.During the high temperature annealing,MgO mainly reacted with SiO_(2) and Fe_(2)SiO_(4) in the surface oxide layer to form Mg2SiO_(4) and Fe_(2)SiO_(4) would respond first,thus forming the glass film with average thickness of 4.87μm.展开更多
SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers（SAMs） by the Liquid Phase Deposition（LPD） method.The as-prepared samples were characterized by X-ray diffraction（...SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers（SAMs） by the Liquid Phase Deposition（LPD） method.The as-prepared samples were characterized by X-ray diffraction（XRD）,atomic force microscope（AFM）,scanning electron microscopy（SEM） and metallographic microscope.Measurement of contact angle showed that the hydrophobe substrate was changed into hydrophile by UV irradiation.AFM photographs of octadecyl-trichloro-silane self-assembled monolayer（OTS-SAM） surface approved that UV irradiation did change the morphology of OTS monolayer and provided evidence for the conversion of hydrophilic characteristic.Photographs of Metallographic Microscope showed that OTS-SAM had an active effect on the deposition of SrTiO3 thin film.XRD and SEM indicated that the thin film was of pure cubic phase SrTiO3 and composed of nanosized grains with a size in the range of 100-500 nm.The formation mechanism of the SrTiO3 film was proposed.展开更多
The development of stationary patterns on a thin polymer surface subject to an electric field is studied by means of the hexagonal-planform weakly nonlinear stability analysis and numerical simulations. The time evolu...The development of stationary patterns on a thin polymer surface subject to an electric field is studied by means of the hexagonal-planform weakly nonlinear stability analysis and numerical simulations. The time evolution of the interface between the air and the polymer film on the unbounded spatial domain is described by a thin film equation, incorporating the electric driving force and the surface diffusion.The nonlinear interfacial growth includes the amplitude equations and superposition of one-dimensional structures at regular orientations. The pattern selection is driven by the subcritical instability mechanism in which the relative thickness of the polymer film plays a critical role.展开更多
A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA)) were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.T...A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA)) were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.The glass transition temperature(T_g)and the mechanical properties of the film formed from the composite latex changed with the evolution of the particle morphology.A photon transmission method was used to monitor the phase structure evolution of films which were prepared from core-shell PBA/P(S...展开更多
Good film formation is one of basic requirements for organic optoelectronic materials to achieve the capability for fabrication of large area devices. Small molecular optoelectronic compounds have a definite chemical ...Good film formation is one of basic requirements for organic optoelectronic materials to achieve the capability for fabrication of large area devices. Small molecular optoelectronic compounds have a definite chemical structure and clear device performance, and thus are welcomed in the field. However, they are generally suffering from poor film formation, especially in a large area. For addressing it, this contribution proposes and demonstrates a strategy, that is, changing them into poly（rod-coil） polymers. With one optoelectronic compound [BDT（DTBT）2] and three poly（rod-coil） polymers （P1, P2, and P3） having different non-conjugated coil segments as examples, the work clearly shows that the change to poly（rod-coil） polymers keeps many basic optoelectronic properties of the refer- ence compound, including light absorption in solution, bandgap and frontier orbital energy levels, but suppresses strong intermolecular interactions and crystalline structure in film state. Further comparisons on film formation quality on glass and ITO glass illustrate that all the three polymers have a better film formation property than the reference compound.展开更多
Organic-inorganic hybrid perovskite materials have attracted significant research efforts because of their outstanding properties. Meanwhile the crystallization of organic-inorganic hybrid perovskite materials can sig...Organic-inorganic hybrid perovskite materials have attracted significant research efforts because of their outstanding properties. Meanwhile the crystallization of organic-inorganic hybrid perovskite materials can significantly influence the films quality. Here, we research the influence of the characteristics of PbI2 thin film on final perovskite films and the mechanisms of film formation based on the two-step sequential deposition method. We found that the characteristics of PbI2 thin film, such as the grain size, the grain shape, the surface roughness and the film densification, have significant effects on the final perovskite films due to different film crystallization process. According to the analysis on the characteristics of the perovskite films obtained from different PbI2precursor, we suggested that the formation of perovskite film begins from the PbI2 crystals expanding when they are converted to MAPbI3 perovskite by migration of MA+ cations from the grain boundaries.展开更多
We utilized controlled vertical drying deposition (CVDD) method,which can fabricate a uniform face-center-cubic (FCC) structure film,to investigate the crack formation and the size dependence of shear modulus in a dry...We utilized controlled vertical drying deposition (CVDD) method,which can fabricate a uniform face-center-cubic (FCC) structure film,to investigate the crack formation and the size dependence of shear modulus in a drying particulate film.We found that both crack spacing and shear modulus depend on colloidal particle size.They drop with increase of particle radius (R) in a single range.Furthermore,compared with the shear modulus variation of a dry particulate film,it was found that both solid part and liquid part in a drying particulate film play equivalent roles in the film mechanical behavior.展开更多
基金Supported by the National Natural Science Foundation of China(41872182)China Postdoctoral Science Foundation(2018T110248,2015M580248)
文摘Gas hydrates have drawn global attentions in the past decades as potential energy resources.It should be noted that there are a variety of possible applications of hydrate-based technologies,including natural gas storage,gas transportation,separation of gas mixture,and seawater desalination.These applications have been critically challenged by insufficient understanding of hydrate formation kinetics.In this work,the literatures on growth kinetic behaviors of hydrate formation from water-hydrocarbon were systematically reviewed.The hydrate crystal growth,hydrate film growth and macroscopic hydrate formation in water system were reviewed,respectively.Firstly,the hydrate crystal growth was analyzed with respect to different positions,such as gas/liquid interface,liquid–liquid interface and gas–liquid–liquid system.Secondly,experimental and modeling studies on the growth of hydrate film at the interfaces between guest phase and water phase were categorized into two groups of lateral growth and thickening growth considering the differences in growth rates.Thirdly,we summarized the promoters and inhibitors reported(biological or chemical,liquid or solid and hydrophobic or hydrophilic)and analyzed the mechanisms affecting hydrate formation in bulk water system.Knowledge gaps and suggestions for further studies on hydrate formation kinetic behaviors are presented.
基金Financial supports from National Key Research and Development Program(No.2016YFB0300305)National Natural Science Foundation of China(No.51804003)are gratefully acknowledged.
文摘The surface oxide layer of grain-oriented electrical steels was investigated by scanning electron microscopy.The formation mechanism and the influence on the glass film of the surface oxide layer were analyzed by the calculation of thermodynamics and kinetics.The surface oxide layer with 2.3μm in thickness is mainly composed of SiO_(2),a small amount of FeO and Fe_(2)SiO_(4).During the formation of surface oxide layer,the restriction factor was the diffusion of O in the oxide layer.At the initial stage of the decarburization annealing,FeO would be formed on the surface layer.SiO_(2) and silicate particles rapidly nucleated,grew and formed a granular oxide layer in the subsurface.As the oxidation layer thickens,the nucleation of new particles decreases,and the growth of oxide particles would be dominant.A lamellar oxide layer was formed between the surface oxide layer and the steel matrix,and eventually formed a typical three-layer structure.During the high temperature annealing,MgO mainly reacted with SiO_(2) and Fe_(2)SiO_(4) in the surface oxide layer to form Mg2SiO_(4) and Fe_(2)SiO_(4) would respond first,thus forming the glass film with average thickness of 4.87μm.
基金Funded by National Natural Science Foundation of China (No. 50672055,50872077)National Key Technology R&D Program (No. 2006BAF02A28)the Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers（SAMs） by the Liquid Phase Deposition（LPD） method.The as-prepared samples were characterized by X-ray diffraction（XRD）,atomic force microscope（AFM）,scanning electron microscopy（SEM） and metallographic microscope.Measurement of contact angle showed that the hydrophobe substrate was changed into hydrophile by UV irradiation.AFM photographs of octadecyl-trichloro-silane self-assembled monolayer（OTS-SAM） surface approved that UV irradiation did change the morphology of OTS monolayer and provided evidence for the conversion of hydrophilic characteristic.Photographs of Metallographic Microscope showed that OTS-SAM had an active effect on the deposition of SrTiO3 thin film.XRD and SEM indicated that the thin film was of pure cubic phase SrTiO3 and composed of nanosized grains with a size in the range of 100-500 nm.The formation mechanism of the SrTiO3 film was proposed.
文摘The development of stationary patterns on a thin polymer surface subject to an electric field is studied by means of the hexagonal-planform weakly nonlinear stability analysis and numerical simulations. The time evolution of the interface between the air and the polymer film on the unbounded spatial domain is described by a thin film equation, incorporating the electric driving force and the surface diffusion.The nonlinear interfacial growth includes the amplitude equations and superposition of one-dimensional structures at regular orientations. The pattern selection is driven by the subcritical instability mechanism in which the relative thickness of the polymer film plays a critical role.
基金This work was financially supported by the Natural Science Foundation of Henan Province(No.0211061600).
文摘A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA)) were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.The glass transition temperature(T_g)and the mechanical properties of the film formed from the composite latex changed with the evolution of the particle morphology.A photon transmission method was used to monitor the phase structure evolution of films which were prepared from core-shell PBA/P(S...
文摘Good film formation is one of basic requirements for organic optoelectronic materials to achieve the capability for fabrication of large area devices. Small molecular optoelectronic compounds have a definite chemical structure and clear device performance, and thus are welcomed in the field. However, they are generally suffering from poor film formation, especially in a large area. For addressing it, this contribution proposes and demonstrates a strategy, that is, changing them into poly（rod-coil） polymers. With one optoelectronic compound [BDT（DTBT）2] and three poly（rod-coil） polymers （P1, P2, and P3） having different non-conjugated coil segments as examples, the work clearly shows that the change to poly（rod-coil） polymers keeps many basic optoelectronic properties of the refer- ence compound, including light absorption in solution, bandgap and frontier orbital energy levels, but suppresses strong intermolecular interactions and crystalline structure in film state. Further comparisons on film formation quality on glass and ITO glass illustrate that all the three polymers have a better film formation property than the reference compound.
文摘Organic-inorganic hybrid perovskite materials have attracted significant research efforts because of their outstanding properties. Meanwhile the crystallization of organic-inorganic hybrid perovskite materials can significantly influence the films quality. Here, we research the influence of the characteristics of PbI2 thin film on final perovskite films and the mechanisms of film formation based on the two-step sequential deposition method. We found that the characteristics of PbI2 thin film, such as the grain size, the grain shape, the surface roughness and the film densification, have significant effects on the final perovskite films due to different film crystallization process. According to the analysis on the characteristics of the perovskite films obtained from different PbI2precursor, we suggested that the formation of perovskite film begins from the PbI2 crystals expanding when they are converted to MAPbI3 perovskite by migration of MA+ cations from the grain boundaries.
基金supported by the National Basic Research Program of China (Grant No. 2011CB710901)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KJCX2-YW-L08)
文摘We utilized controlled vertical drying deposition (CVDD) method,which can fabricate a uniform face-center-cubic (FCC) structure film,to investigate the crack formation and the size dependence of shear modulus in a drying particulate film.We found that both crack spacing and shear modulus depend on colloidal particle size.They drop with increase of particle radius (R) in a single range.Furthermore,compared with the shear modulus variation of a dry particulate film,it was found that both solid part and liquid part in a drying particulate film play equivalent roles in the film mechanical behavior.
