It has been a long-standing puzzling problem that some glasses exhibit higher glass transition temperatures(denoting high stability)but lower activation energy for relaxations(denoting low stability).In this paper,the...It has been a long-standing puzzling problem that some glasses exhibit higher glass transition temperatures(denoting high stability)but lower activation energy for relaxations(denoting low stability).In this paper,the relaxation kinetics of the nanoconfined D-mannitol(DM)glass was studied systematically using a high-precision and high-rate nanocalorimeter.The nanoconfined DM exhibits enhanced thermal stability compared to the free DM.For example,the critical cooling rate for glass formation decreases from 200 K/s to below 1 K/s;the Tg increases by about 20 K–50 K.The relaxation kinetics is analyzed based on the absolute reaction rate theory.It is found that,even though the activation energy E^(*)decreases,the activation entropy S^(*)decreases much more for the nanoconfined glass that yields a large activation free energy G^(*)and higher thermal stability.These results suggest that the activation entropy may provide new insights in understanding the abnormal kinetics of nanoconfined glassy systems.展开更多
We analyze oxidative activity of DNA due to fluorescence of chromosomes inside cells, using flow cytometry method with nanometer spatial resolution. Statistics of fluorescence is presented in histogram as frequency di...We analyze oxidative activity of DNA due to fluorescence of chromosomes inside cells, using flow cytometry method with nanometer spatial resolution. Statistics of fluorescence is presented in histogram as frequency distributions of flashes in the dependence on their intensity and in distributions of Shannon entropy, which was defined on the base of normalized distribution of information in original histogram for frequency of flashes. We show that overall sum of entropy, i.e. total entropy E , for any histogram is invariant and has identical trends of changes all values of E(r) = lnr at reduction of histogram’ rank r. This invariance reflects informational homeostasis of chromosomes activity in multi-scale networks of entropy inside all cells in various samples of blood for DNA inside neutrophils, lymphocytes, inside all leukocytes of human and inside chicken erythrocytes for various dyes, colors and various excitations of fluorescence. Informational homeostasis of oxidative activity of 3D DNA in the full set of chromosomes inside living cells exists for any Shannon-Weaver index of biodiversity of cells, at any state of health different beings. Regulation perturbations in information activity DNA provides informational adaptability and vitality of cells at homeostasis support. Noises of entropy, during regulation of informational homeostasis, depend on the states of health in real time. The main structural reconstructions of chromosomal correlations, corresponding to self-regulation of homeostasis, occur in the most large-scale networks of entropy, for rank r<32. We show that stability of homeostasis is supported by activity of all 46 chromosomes inside cells. Patterns, hidden switching and branching in sequences of averages of H?lder and central moments for noises in regulation of homeostasis define new opportunities in diagnostics of health and immunity. All people and all aerobic beings have one overall homeostatic level for countdown of information activity of DNA inside cells. We noted very bad and dangerous properties of artificial cells with other levels of informational homeostasis for all aerobic beings in foods, medical treatment and in biotechnologies.展开更多
Au Pd nanoalloys with tunable Pd concentrations have been synthesized and used as model catalysts. They have been directly imaged by high-angle annular dark-field scanning transmission electron microscopy and investig...Au Pd nanoalloys with tunable Pd concentrations have been synthesized and used as model catalysts. They have been directly imaged by high-angle annular dark-field scanning transmission electron microscopy and investigated by thorough analyses of their extended X-ray absorption fine structure, X-ray absorption near-edge structure, X-ray diffraction and X-ray photoelectron spectroscopy measurements. The bimetallic nanoparticles are embedded in a carbonaceous matrix and have almost an identical structure at the atomic level and the same electronic properties as Au Pd bulk alloys with the same compositions. The d-electron increase at surface Pd sites is determined by the Pd concentration of the alloy. Similarly, their activation entropy and catalytic activity for the hydrogenation of quinoline is related to the Pd concentration, with Au50 Pd50 the most active of the alloys investigated. An almost 11 times higher activity was achieved compared to a pure Pd catalyst. The experimentally measurable surface d charge at the Pd sites in the Au Pd was found to linearly correlate with the activation entropy and catalytic activity for the hydrogenation of quinoline. The alloy structure is stable, showing negligible metal segregation, dissolution-redeposition and aggregation during the hydrogenation process which involves strong adsorption.展开更多
The amounts of chloride ions diffused in four soils of different textures at the same water content under different temperature and at varied time were measured by the diffusion cell method using 36Cl-labelled CaCl2 s...The amounts of chloride ions diffused in four soils of different textures at the same water content under different temperature and at varied time were measured by the diffusion cell method using 36Cl-labelled CaCl2 solution. Five kinetic models were used to fit the dynamic process of the diffusion of chloride ions in the soils. It was found that Elovich equation or power function equation was the best model to describe the process. The pseudothermodynamic parameters, i. e. the net reaction energyl the activation entropy,activation enthalpy and activation free energy of the diffusion, were derived from the absolute reaction-rate theory. The results showed that these parameters decreased in the order of loessal soil > black in soil >lou soil > yellow cinnamon soil, which indicated that the force and the heat-energy barrier to be overcome for diffusion decreased, the diffusion rate increased and the disorder of the soil-solution-ion system due to diffusion decreased successively with the texture becoming heavier in the four soils.展开更多
基金the National Natural Science Foundation of China(Grant Nos.52001319,52071327,51922102,51771216,and 51701230)the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LR18E010002)+1 种基金the Ningbo 2025 Science and Technology Innovation Project(Grant No.2019B10051)the Natural Science Foundation of Ningbo City(Grant No.202003N4354)。
文摘It has been a long-standing puzzling problem that some glasses exhibit higher glass transition temperatures(denoting high stability)but lower activation energy for relaxations(denoting low stability).In this paper,the relaxation kinetics of the nanoconfined D-mannitol(DM)glass was studied systematically using a high-precision and high-rate nanocalorimeter.The nanoconfined DM exhibits enhanced thermal stability compared to the free DM.For example,the critical cooling rate for glass formation decreases from 200 K/s to below 1 K/s;the Tg increases by about 20 K–50 K.The relaxation kinetics is analyzed based on the absolute reaction rate theory.It is found that,even though the activation energy E^(*)decreases,the activation entropy S^(*)decreases much more for the nanoconfined glass that yields a large activation free energy G^(*)and higher thermal stability.These results suggest that the activation entropy may provide new insights in understanding the abnormal kinetics of nanoconfined glassy systems.
文摘We analyze oxidative activity of DNA due to fluorescence of chromosomes inside cells, using flow cytometry method with nanometer spatial resolution. Statistics of fluorescence is presented in histogram as frequency distributions of flashes in the dependence on their intensity and in distributions of Shannon entropy, which was defined on the base of normalized distribution of information in original histogram for frequency of flashes. We show that overall sum of entropy, i.e. total entropy E , for any histogram is invariant and has identical trends of changes all values of E(r) = lnr at reduction of histogram’ rank r. This invariance reflects informational homeostasis of chromosomes activity in multi-scale networks of entropy inside all cells in various samples of blood for DNA inside neutrophils, lymphocytes, inside all leukocytes of human and inside chicken erythrocytes for various dyes, colors and various excitations of fluorescence. Informational homeostasis of oxidative activity of 3D DNA in the full set of chromosomes inside living cells exists for any Shannon-Weaver index of biodiversity of cells, at any state of health different beings. Regulation perturbations in information activity DNA provides informational adaptability and vitality of cells at homeostasis support. Noises of entropy, during regulation of informational homeostasis, depend on the states of health in real time. The main structural reconstructions of chromosomal correlations, corresponding to self-regulation of homeostasis, occur in the most large-scale networks of entropy, for rank r<32. We show that stability of homeostasis is supported by activity of all 46 chromosomes inside cells. Patterns, hidden switching and branching in sequences of averages of H?lder and central moments for noises in regulation of homeostasis define new opportunities in diagnostics of health and immunity. All people and all aerobic beings have one overall homeostatic level for countdown of information activity of DNA inside cells. We noted very bad and dangerous properties of artificial cells with other levels of informational homeostasis for all aerobic beings in foods, medical treatment and in biotechnologies.
文摘Au Pd nanoalloys with tunable Pd concentrations have been synthesized and used as model catalysts. They have been directly imaged by high-angle annular dark-field scanning transmission electron microscopy and investigated by thorough analyses of their extended X-ray absorption fine structure, X-ray absorption near-edge structure, X-ray diffraction and X-ray photoelectron spectroscopy measurements. The bimetallic nanoparticles are embedded in a carbonaceous matrix and have almost an identical structure at the atomic level and the same electronic properties as Au Pd bulk alloys with the same compositions. The d-electron increase at surface Pd sites is determined by the Pd concentration of the alloy. Similarly, their activation entropy and catalytic activity for the hydrogenation of quinoline is related to the Pd concentration, with Au50 Pd50 the most active of the alloys investigated. An almost 11 times higher activity was achieved compared to a pure Pd catalyst. The experimentally measurable surface d charge at the Pd sites in the Au Pd was found to linearly correlate with the activation entropy and catalytic activity for the hydrogenation of quinoline. The alloy structure is stable, showing negligible metal segregation, dissolution-redeposition and aggregation during the hydrogenation process which involves strong adsorption.
文摘The amounts of chloride ions diffused in four soils of different textures at the same water content under different temperature and at varied time were measured by the diffusion cell method using 36Cl-labelled CaCl2 solution. Five kinetic models were used to fit the dynamic process of the diffusion of chloride ions in the soils. It was found that Elovich equation or power function equation was the best model to describe the process. The pseudothermodynamic parameters, i. e. the net reaction energyl the activation entropy,activation enthalpy and activation free energy of the diffusion, were derived from the absolute reaction-rate theory. The results showed that these parameters decreased in the order of loessal soil > black in soil >lou soil > yellow cinnamon soil, which indicated that the force and the heat-energy barrier to be overcome for diffusion decreased, the diffusion rate increased and the disorder of the soil-solution-ion system due to diffusion decreased successively with the texture becoming heavier in the four soils.
