Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liqu...Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.展开更多
In this paper, pyrolysis of Indonesian oil sands （lOS） was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducte...In this paper, pyrolysis of Indonesian oil sands （lOS） was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducted to study the thermal decomposition behaviors of lOS, showing that 550 ℃ might be the pyrolysis final temperature. A explanation of the heat-mass transfer process was presented to demonstrate the influence of mi- crowave-assisted pyrolysis on the liquid product distribution. The heat-mass transfer model was also useful to explain the increase of liquid product yield and heavy component content at the same heating rate by two differ- ent heating methods. Experiments were carried out using a fixed bed reactor with and without the microwave irradiation. The results showed that liquid product yield was increased during microwave induced pyrolysis, while the formation of gas and solid residue was reduced in comparison with the conventional pyrolysis. Moreover, the liquid product characterization by elemental analysis and GC-MS indicated the significant effect on the liquid chemical composition by microwave irradiation. High polarity substances （ε 〉 10 at 25 ℃）, such as oxy- organics were increased, while relatively low polarity substances （ε 〈 2 at 25℃）, such as aliphatic hydrocarbons were decreased, suggesting that microwave enhanced the relative volatility of high polarity substances. The yield improvement and compositional variations in the liquid product promoted by the microwave-assisted pyrolysis deserve the further exploitation in the future,展开更多
Anodic processes on Cu-10 Al electrode in molten KF-AlF3-Al2O3(saturated) and suspensions were characterized using chronopotentiometric and cyclic voltammetric techniques. Effects of cryolite ratio(CR= x(KF)/x(AlF3)),...Anodic processes on Cu-10 Al electrode in molten KF-AlF3-Al2O3(saturated) and suspensions were characterized using chronopotentiometric and cyclic voltammetric techniques. Effects of cryolite ratio(CR= x(KF)/x(AlF3)), temperature and particle volume fraction(φ) on the electrochemical behaviour of the anode were demonstrated. Initially, the anode was polarised in the galvanostatic mode in melt and suspensions(φ=0.12, 0.15) at 750 ℃ with 0.4 A/cm^2 current density. The anode potential in melt varied between 2.5 and 3.2 V and in suspensions(φ= 0.12) between 3.3 and 3.4 V. XRD analysis was conducted to study the oxide phases on the anode surface. Anode limiting current densities and mass transfer coefficients drastically decreased with the increase of φ in the suspension. The results suggest that the Cu-10 Al electrode works better in suspensions with CR of 1.4 and particle volume fraction of 0.09 at 800 ℃.展开更多
Although many ionic liquids have been reported, their polarity is not completely understood. Different empirical polarity scales for molecular solvents always lead to different polarity orders when they are applied on...Although many ionic liquids have been reported, their polarity is not completely understood. Different empirical polarity scales for molecular solvents always lead to different polarity orders when they are applied on ionic liquids. Based on a literature survey, this review summarizes the recent polarity scales of ionic liquids according to the following 4 classes:(1) equilibrium and kinetic rate constants of chemical reactions;(2) empirical polar parameters of ionic liquids;(3) spectral properties of probe molecules;(4) multiparameter approaches. In addition, their interrelations are presented. A systematic understanding of the relationship between different polarity parameters of ionic liquids is of great importance for finding a universal set of parameters that can be used to predict the polarities of ionic liquids quantitatively. The potential utilization of the electron paramagnetic resonance in this field is also addressed.展开更多
In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquidshave been developed in this paper to roughen the surface of the indium tin oxide (ITO) current...In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquidshave been developed in this paper to roughen the surface of the indium tin oxide (ITO) current spreading layer of LEDs. As aresult, the textured transparent ITO layer greatly enhanced the external quantum efficiency of the LEDs. Provided that a wafersample was dipped in a kind of corrosive liquid developed by us for only about 60 s, the light output powers of the LEDs canbe promoted by 24.7%, compared with conventional GaN-based LEDs. It is obvious that the presented method is simple, rapidand cost-effective.展开更多
The theory of limit cycles was applied to hydraulic hybrid vehicle (HHV) to analyze the dynamic characteristics of the system. The exact mathematical models based on configuration diagram of HHV were built to study on...The theory of limit cycles was applied to hydraulic hybrid vehicle (HHV) to analyze the dynamic characteristics of the system. The exact mathematical models based on configuration diagram of HHV were built to study on equilibrium points, nonexistence of limit cycle and stability of equilibrium points. The analysis showed that if the Young's modulus of fluid is neglected, the equilibrium points of the system will be distributed on both sides of the initial function. In addition, there is a unique equilibrium point according to the practical signification of the system parameters. The nonexistence analysis showed that there is no limit cycle for the system, no matter how the viscosity coefficient B changes. The stability analysis of equilibrium points showed that the system is asymptotically stable about the equilibrium point at B≥0 and the equilibrium point is the center point of the system at B=0. Finally, the phase diagrams of global topological structure of HHV system were entirely described according to qualitative analysis of the singular points at infinity.展开更多
基金the Natural Science Foundation of Guangdong Province (No. 020839).
文摘Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.
基金Supported by the National Key Research and Development Program of China(2016YFB0301800)the partial support by The Royal Society International Exchange Award(IE161344)the State Scholarship Fund of China Scholarship Council(CSC)(201706255020)
文摘In this paper, pyrolysis of Indonesian oil sands （lOS） was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducted to study the thermal decomposition behaviors of lOS, showing that 550 ℃ might be the pyrolysis final temperature. A explanation of the heat-mass transfer process was presented to demonstrate the influence of mi- crowave-assisted pyrolysis on the liquid product distribution. The heat-mass transfer model was also useful to explain the increase of liquid product yield and heavy component content at the same heating rate by two differ- ent heating methods. Experiments were carried out using a fixed bed reactor with and without the microwave irradiation. The results showed that liquid product yield was increased during microwave induced pyrolysis, while the formation of gas and solid residue was reduced in comparison with the conventional pyrolysis. Moreover, the liquid product characterization by elemental analysis and GC-MS indicated the significant effect on the liquid chemical composition by microwave irradiation. High polarity substances （ε 〉 10 at 25 ℃）, such as oxy- organics were increased, while relatively low polarity substances （ε 〈 2 at 25℃）, such as aliphatic hydrocarbons were decreased, suggesting that microwave enhanced the relative volatility of high polarity substances. The yield improvement and compositional variations in the liquid product promoted by the microwave-assisted pyrolysis deserve the further exploitation in the future,
文摘Anodic processes on Cu-10 Al electrode in molten KF-AlF3-Al2O3(saturated) and suspensions were characterized using chronopotentiometric and cyclic voltammetric techniques. Effects of cryolite ratio(CR= x(KF)/x(AlF3)), temperature and particle volume fraction(φ) on the electrochemical behaviour of the anode were demonstrated. Initially, the anode was polarised in the galvanostatic mode in melt and suspensions(φ=0.12, 0.15) at 750 ℃ with 0.4 A/cm^2 current density. The anode potential in melt varied between 2.5 and 3.2 V and in suspensions(φ= 0.12) between 3.3 and 3.4 V. XRD analysis was conducted to study the oxide phases on the anode surface. Anode limiting current densities and mass transfer coefficients drastically decreased with the increase of φ in the suspension. The results suggest that the Cu-10 Al electrode works better in suspensions with CR of 1.4 and particle volume fraction of 0.09 at 800 ℃.
基金supported by the National Natural Science Foundation of China (21573196)the Program for Zhejiang Leading Team of S&T Innovation (2011R50007)the Fundamental Research Funds of the Central Universities
文摘Although many ionic liquids have been reported, their polarity is not completely understood. Different empirical polarity scales for molecular solvents always lead to different polarity orders when they are applied on ionic liquids. Based on a literature survey, this review summarizes the recent polarity scales of ionic liquids according to the following 4 classes:(1) equilibrium and kinetic rate constants of chemical reactions;(2) empirical polar parameters of ionic liquids;(3) spectral properties of probe molecules;(4) multiparameter approaches. In addition, their interrelations are presented. A systematic understanding of the relationship between different polarity parameters of ionic liquids is of great importance for finding a universal set of parameters that can be used to predict the polarities of ionic liquids quantitatively. The potential utilization of the electron paramagnetic resonance in this field is also addressed.
基金supported by the Natural Science Foundation of Guangdong Province, China (Grant Nos. 8251063101000007, 10151063101000009 and 9451063101002082)the Scientific & Technological Plan of Guangdong Province (Grant Nos. 2008B010200004, 2010B010600030 and 2009B011100003)+2 种基金the National Natural Science Foundation of China(Grant Nos. 61078046 and 10904042)the Key Project of Chinese Ministryof Education (Grant No. 210157)the Scientific & Technological Project of Education Department of Hubei Province (Grant No. D20101104)
文摘In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquidshave been developed in this paper to roughen the surface of the indium tin oxide (ITO) current spreading layer of LEDs. As aresult, the textured transparent ITO layer greatly enhanced the external quantum efficiency of the LEDs. Provided that a wafersample was dipped in a kind of corrosive liquid developed by us for only about 60 s, the light output powers of the LEDs canbe promoted by 24.7%, compared with conventional GaN-based LEDs. It is obvious that the presented method is simple, rapidand cost-effective.
基金supported by the National Natural Science Foundation of China (Grant No. 50475011)
文摘The theory of limit cycles was applied to hydraulic hybrid vehicle (HHV) to analyze the dynamic characteristics of the system. The exact mathematical models based on configuration diagram of HHV were built to study on equilibrium points, nonexistence of limit cycle and stability of equilibrium points. The analysis showed that if the Young's modulus of fluid is neglected, the equilibrium points of the system will be distributed on both sides of the initial function. In addition, there is a unique equilibrium point according to the practical signification of the system parameters. The nonexistence analysis showed that there is no limit cycle for the system, no matter how the viscosity coefficient B changes. The stability analysis of equilibrium points showed that the system is asymptotically stable about the equilibrium point at B≥0 and the equilibrium point is the center point of the system at B=0. Finally, the phase diagrams of global topological structure of HHV system were entirely described according to qualitative analysis of the singular points at infinity.
