Based on the solubility in supercritical CO2,two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies.The experimental results showed ...Based on the solubility in supercritical CO2,two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies.The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 μm can be made via solution enhanced dispersion by supercritical fluids(SEDS) process,in which CO2 worked as turbulent anti-solvent;while for astaxanthin,micronized particles with mean particle size of 0.3-0.8 μm were also made successfully by rapid expansion supercritical solution(RESS) process.展开更多
The relation between the critical radius and the particle size distribution for generalized Ostwald type ripening processes whereby the mass transfer coefficient is modelled by a power law was derived. The critical ra...The relation between the critical radius and the particle size distribution for generalized Ostwald type ripening processes whereby the mass transfer coefficient is modelled by a power law was derived. The critical radius is determined by the growth rate, the mass transfer coefficient and the mass balance, and is independent of whether the limiting stationary growth regime has been obtained.展开更多
Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to f...Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.展开更多
By means of critical behaviors of the dynamical fermion mass in four-fermion interaction models, we show by explicit calculations that when T = 0 the particle density will have a discontinuous jumping across the criti...By means of critical behaviors of the dynamical fermion mass in four-fermion interaction models, we show by explicit calculations that when T = 0 the particle density will have a discontinuous jumping across the critical chemical potential μ<SUB>c</SUB> in 2D and 3D Gross-Neveu (GN) model and these physically explain the first-order feature of the corresponding symmetry restoring phase transitions. For the second-order phase transitions in the 3D GN model when T → 0 and in 4D Nambu–Jona–Lasinio (NJL) model when T = 0, it is proven that the particle density itself will be continuous across μ<SUB>c</SUB> but its derivative over the chemical potential μ will have a discontinuous jumping. The results give a physical explanation of implications of the tricritical point in the 3D GN model. The discussions also show effectiveness of the critical analysis approach of phase transitions.展开更多
The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding struct...The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding structural and textural properties by XRD, FTIR, nitrogen adsorption/desorption, thermal analysis and ESA experiments. Palladium supported MOF-5 catalyst has been prepared by adsorption inclusion method. The catalyst was activated by treatment with supercritical carbon dioxide （scCO2） followed by mild reduction with hydrogen solved in scCO2. The obtained catalyst is shown to be stable and active and shape selective in hydrogenation reactions of alkenes using supercritical carbon dioxide as reaction medium. The catalytic active Pd species are located inside the pores. Positive surface charging seems to prevent deposition of active species at the crystal surface of the MOF. The catalyst is long time stable and re-useably. These findings show the potential of porous MOFs for applications under supercritical conditons and resisted repeated pressuring to 120 bar at elevated temperature.展开更多
A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO4particles with high purity and crystallinity.The structure and morphology of LiFePO4particles were characterized by X-ray diffraction a...A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO4particles with high purity and crystallinity.The structure and morphology of LiFePO4particles were characterized by X-ray diffraction and scanning electron microscope.The electrochemical tests were carried out to determine the reversible capacity,rate and cycling performance of the LiFePO4particles as cathode material for lithium ion battery.Experimental results show that solvent and calcining time have significant effects on purity,size and morphology of LiFePO4particles.Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles.The size of LiFePO4particles as-prepared is about 100-300 nm.The specific discharge capacities of the LiFePO4particles are 151.3 and 128.0 mA·h·g?1 after first cycle at the rates of 0.1 and 1.0 C,respectively.It retains 95.0%of the initial capacity after 100 cycles at 1.0 C.展开更多
Using the measure of interference defined in this paper, we investigate the quantum phase transition of one-dimensional Ising chains. We find that thermal fluctuations affect the interference more strongly at the crit...Using the measure of interference defined in this paper, we investigate the quantum phase transition of one-dimensional Ising chains. We find that thermal fluctuations affect the interference more strongly at the critical point. We also show that the derivative of the interference with respect to the coupling parameter, A, can be depressed by the thermal fluctuation. Finally, we find that this suppression is due to multi-particle excitations.展开更多
基金Supported partially by the China Ministry of Science and Technology for the China’s Agenda 21 Strategic Research (MOST,2008IM021900)the General Administration of Quality Supervision Inspection and Quarantine of the People’s Republic of China for the 4th Food Safety Research (AQSIQ 2008:ASPAQ0809)
文摘Based on the solubility in supercritical CO2,two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies.The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 μm can be made via solution enhanced dispersion by supercritical fluids(SEDS) process,in which CO2 worked as turbulent anti-solvent;while for astaxanthin,micronized particles with mean particle size of 0.3-0.8 μm were also made successfully by rapid expansion supercritical solution(RESS) process.
基金Project (No. 20076039) supported by the National Science Founda-tion of China
文摘The relation between the critical radius and the particle size distribution for generalized Ostwald type ripening processes whereby the mass transfer coefficient is modelled by a power law was derived. The critical radius is determined by the growth rate, the mass transfer coefficient and the mass balance, and is independent of whether the limiting stationary growth regime has been obtained.
基金supported by the National Natural Science Foundation of China (Grant No. 41172209)National Public Welfare Scientific Research Project (Grant No. 201301090)
文摘Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.
基金The project supported by National Natural Science Foundation ot China
文摘By means of critical behaviors of the dynamical fermion mass in four-fermion interaction models, we show by explicit calculations that when T = 0 the particle density will have a discontinuous jumping across the critical chemical potential μ<SUB>c</SUB> in 2D and 3D Gross-Neveu (GN) model and these physically explain the first-order feature of the corresponding symmetry restoring phase transitions. For the second-order phase transitions in the 3D GN model when T → 0 and in 4D Nambu–Jona–Lasinio (NJL) model when T = 0, it is proven that the particle density itself will be continuous across μ<SUB>c</SUB> but its derivative over the chemical potential μ will have a discontinuous jumping. The results give a physical explanation of implications of the tricritical point in the 3D GN model. The discussions also show effectiveness of the critical analysis approach of phase transitions.
文摘The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding structural and textural properties by XRD, FTIR, nitrogen adsorption/desorption, thermal analysis and ESA experiments. Palladium supported MOF-5 catalyst has been prepared by adsorption inclusion method. The catalyst was activated by treatment with supercritical carbon dioxide （scCO2） followed by mild reduction with hydrogen solved in scCO2. The obtained catalyst is shown to be stable and active and shape selective in hydrogenation reactions of alkenes using supercritical carbon dioxide as reaction medium. The catalytic active Pd species are located inside the pores. Positive surface charging seems to prevent deposition of active species at the crystal surface of the MOF. The catalyst is long time stable and re-useably. These findings show the potential of porous MOFs for applications under supercritical conditons and resisted repeated pressuring to 120 bar at elevated temperature.
文摘A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO4particles with high purity and crystallinity.The structure and morphology of LiFePO4particles were characterized by X-ray diffraction and scanning electron microscope.The electrochemical tests were carried out to determine the reversible capacity,rate and cycling performance of the LiFePO4particles as cathode material for lithium ion battery.Experimental results show that solvent and calcining time have significant effects on purity,size and morphology of LiFePO4particles.Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles.The size of LiFePO4particles as-prepared is about 100-300 nm.The specific discharge capacities of the LiFePO4particles are 151.3 and 128.0 mA·h·g?1 after first cycle at the rates of 0.1 and 1.0 C,respectively.It retains 95.0%of the initial capacity after 100 cycles at 1.0 C.
基金Supported by National Natural Science Foundation of China under Grant No.11355013the Talent Introduction Foundation of Kunming University of Science and Technology under Grant No.2012017034
文摘Using the measure of interference defined in this paper, we investigate the quantum phase transition of one-dimensional Ising chains. We find that thermal fluctuations affect the interference more strongly at the critical point. We also show that the derivative of the interference with respect to the coupling parameter, A, can be depressed by the thermal fluctuation. Finally, we find that this suppression is due to multi-particle excitations.
