Our analysis of published results of experiments in the Polar Regions substantiates and further develops our new approach to the photochemical processes in the polar stratosphere involving the charged particles. The d...Our analysis of published results of experiments in the Polar Regions substantiates and further develops our new approach to the photochemical processes in the polar stratosphere involving the charged particles. The dipole interaction of molecules with charged particles, primarily with ions, leads to the adhesion and disintegration of a number of molecules including ozone. Molecules acquire additional energy on the surface of the charged particles, enabling reactions that are not possible in space. Galactic cosmic rays are the main source of ions in the polar stratosphere, their equilibrium concentration at altitudes of 15 to 25 km can reach up ~ （1-5） ~ 103 ions/cm3. Estimations show that if the ozone destruction in the regime of＂collision＂ with ions then the lifetime of ozone will vary from 10 days to 2 months. We suppose that alongside with the chlorine mechanism of ozone destruction there is a mechanism of ozone decay on a charged particle which can act also at those latitudes and altitudes where chlorine oxide CIO is absent, as well as in the night conditions. Here, we demonstrated the close connection of photochemical processes with the dynamic, electrical and condensational phenomena in the stratosphere, in particular, with the accumulation of unipolar charged particles on the upper and lower boundaries of the polar stratospheric clouds and aerosol layers as a result of the activity of the global electric circuit.展开更多
This work presents a critical review on the studies of defect chemistry of oxide nanoparticles for creating new functionalities pertinent to energy applications including dilute-magnetic semiconductors,giant-dielectri...This work presents a critical review on the studies of defect chemistry of oxide nanoparticles for creating new functionalities pertinent to energy applications including dilute-magnetic semiconductors,giant-dielectrics,or white light generation.Emphasis is placed on the relationships between the internal structure and defective surfaces of oxide nanoparticles and their synergy in tailoring the materials properties.This review is arranged in a sequence:(1) structural fundamentals of bulk oxides,using TiO2 as a model simple oxide to highlight the importance of polymorphs in tuning the electronic structures;(2) structural features of simple oxide nanoparticles distinct from the bulk,which show that nanoparticles can be considered as a special solid under the compression as originated from the surface defect dipole-dipole interactions;and(3) new functions achieved through extending the defect chemistry concept to the assembled architectures or multi-component oxide nanoparticles,in which defect surfaces enable the localized electrons or intermediate levels to produce giant dielectric performance or tunable light generation.It is concluded that understandings of defect chemistry provide diverse possibilities to manipulate electrons in oxide nanoparticles for functionalities in energy-relevant applications.展开更多
We present a facile and controllable method for the large-scale fabrication of highly-ordered octahedral Fe3O4 colloidal ＂single crystals＂ without the assistance of a substrate. Oleic acid is used to reduce the solu...We present a facile and controllable method for the large-scale fabrication of highly-ordered octahedral Fe3O4 colloidal ＂single crystals＂ without the assistance of a substrate. Oleic acid is used to reduce the solubility of the nano-building blocks in colloidal solution and to induce a ＂crystallization＂ process. Our colloidal crystals are of multimicron size and show typical crystallographic characteristics. They have a very robust structure and can serve as a novel ordered magnetic mesoporous material with a relatively narrow pore size distribution. The sample possesses an extremely high Verwey transition temperature （Tv） of 100 K and a high saturation magnetization （Ms） of 86 emu/g at 5 K based on its good crystallinity, as well as the interparticle dipolar interaction behavior arising from its unique structure. Electrochemical measurements have demonstrated the excellent capacity of the mesoporous colloidal crystals when used in lithium-ion batteries.展开更多
文摘Our analysis of published results of experiments in the Polar Regions substantiates and further develops our new approach to the photochemical processes in the polar stratosphere involving the charged particles. The dipole interaction of molecules with charged particles, primarily with ions, leads to the adhesion and disintegration of a number of molecules including ozone. Molecules acquire additional energy on the surface of the charged particles, enabling reactions that are not possible in space. Galactic cosmic rays are the main source of ions in the polar stratosphere, their equilibrium concentration at altitudes of 15 to 25 km can reach up ~ （1-5） ~ 103 ions/cm3. Estimations show that if the ozone destruction in the regime of＂collision＂ with ions then the lifetime of ozone will vary from 10 days to 2 months. We suppose that alongside with the chlorine mechanism of ozone destruction there is a mechanism of ozone decay on a charged particle which can act also at those latitudes and altitudes where chlorine oxide CIO is absent, as well as in the night conditions. Here, we demonstrated the close connection of photochemical processes with the dynamic, electrical and condensational phenomena in the stratosphere, in particular, with the accumulation of unipolar charged particles on the upper and lower boundaries of the polar stratospheric clouds and aerosol layers as a result of the activity of the global electric circuit.
基金financially supported by the National Natural Science Foundation of China (21025104, 20831004 & 91022018)National Basic Research Program of China (2011CBA00501 & 2007CB613301)
文摘This work presents a critical review on the studies of defect chemistry of oxide nanoparticles for creating new functionalities pertinent to energy applications including dilute-magnetic semiconductors,giant-dielectrics,or white light generation.Emphasis is placed on the relationships between the internal structure and defective surfaces of oxide nanoparticles and their synergy in tailoring the materials properties.This review is arranged in a sequence:(1) structural fundamentals of bulk oxides,using TiO2 as a model simple oxide to highlight the importance of polymorphs in tuning the electronic structures;(2) structural features of simple oxide nanoparticles distinct from the bulk,which show that nanoparticles can be considered as a special solid under the compression as originated from the surface defect dipole-dipole interactions;and(3) new functions achieved through extending the defect chemistry concept to the assembled architectures or multi-component oxide nanoparticles,in which defect surfaces enable the localized electrons or intermediate levels to produce giant dielectric performance or tunable light generation.It is concluded that understandings of defect chemistry provide diverse possibilities to manipulate electrons in oxide nanoparticles for functionalities in energy-relevant applications.
文摘We present a facile and controllable method for the large-scale fabrication of highly-ordered octahedral Fe3O4 colloidal ＂single crystals＂ without the assistance of a substrate. Oleic acid is used to reduce the solubility of the nano-building blocks in colloidal solution and to induce a ＂crystallization＂ process. Our colloidal crystals are of multimicron size and show typical crystallographic characteristics. They have a very robust structure and can serve as a novel ordered magnetic mesoporous material with a relatively narrow pore size distribution. The sample possesses an extremely high Verwey transition temperature （Tv） of 100 K and a high saturation magnetization （Ms） of 86 emu/g at 5 K based on its good crystallinity, as well as the interparticle dipolar interaction behavior arising from its unique structure. Electrochemical measurements have demonstrated the excellent capacity of the mesoporous colloidal crystals when used in lithium-ion batteries.
