Nanocrystalline nonferrous metals (Cu, Al, and Ag) were synthesized by flow-levitation-molding method. The microstructure of the as-prepared nanocrystalline metals was characterized by XRD and FESEM. The microhardness...Nanocrystalline nonferrous metals (Cu, Al, and Ag) were synthesized by flow-levitation-molding method. The microstructure of the as-prepared nanocrystalline metals was characterized by XRD and FESEM. The microhardness and electrical resistivity were tested by the HMV-2 type Microhardness Tester and 6157 type Electrometer, respectively. The synthesis process was also studied. The results show that the spheriform particles in nanocrystalline metals have average grain size of 20-30 nm. The relative density of nanocrystalline Cu, Al, and Ag are 95.1%, 98.1% and 98.3%, respectively. The microhardness of nanocrystalline Cu, Al and Ag are 2.01, 2.11 and 1.26 GPa respectively, which are larger than those of their coarse-grained counterparts by the factor of 4.5, 14, and 2.5, respectively. The electrical resistivity of nanocrystalline Cu at room temperature is 1.5×10-7 Ω·m, which is higher than coarse-grained Cu by a factor of 7.5. The pressure is the predominant factor influencing the density of the as-prepared nanocrystalline nonferrous metals.展开更多
The anaerobic digestion of sludge has recently received increased interest because of the potential to transform organic matter into methane‐rich biogas. However, digested sludge, the residue produced in that process...The anaerobic digestion of sludge has recently received increased interest because of the potential to transform organic matter into methane‐rich biogas. However, digested sludge, the residue produced in that process, still contains high levels of heavy metals and other harmful substances that might make traditional disposal difficult. We have devised a facile method of converting digested sludge into a mesoporous material that acts as an effective and stable heterogeneous catalyst for the photo‐Fenton reaction. A comparison of the removal of rhodamine B under different conditions showed that FAS‐1‐350, which was synthesized by mixing the digested sludge with a 1 mol/L（NH4）2Fe（SO4）2 solution followed by calcination at 350 °C, exhibited the best catalytic activity owing to its faster reaction rate and lower degree of Fe leaching. The results indicate that Fe^（2＋）‐loaded catalysts have significant potential to act as stable and efficient heterogeneous promoters for the photo‐Fenton reaction, with better performance than Fe^3＋‐loaded catalysts because the Fe（II）/Fe（III）compounds formed in the calcination process are necessary to sustain the Fenton reaction. This protocol provides an alternative, environmentally friendly method of reusing digested sludge and demonstrates an easily synthesized mesoporous material that effectively degrades azo dyes.展开更多
Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage.Herein,we report the coexistence of ferroelectricity and ferromagnetism in two-dimensiona...Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage.Herein,we report the coexistence of ferroelectricity and ferromagnetism in two-dimensional Fedoped In2Se3(Fe0.16In1.84Se3,FIS).The Fe atoms were doped at the In atom sites and the Fe content is^3.22%according to the experiments.Our first-principles calculation based on the density-functional theory predicts a magnetic moment of 5μB per Fe atom when Fe substitutes In sites in In2Se3.The theoretical prediction was further confirmed experimentally by magnetic measurement.The results indicate that pure In2Se3 is diamagnetic,whereas FIS exhibits ferromagnetic behavior with a parallel anisotropy at 2 K and a Curie temperature of^8 K.Furthermore,the sample maintains stable room-temperature ferroelectricity in piezoresponse force microscopy(PFM)measurement after the introduction of Fe atom into the ferroelectric In2Se3 nanoflakes.The findings indicate that the layered Fe0.16In1.84Se3 materials have potential in future nanoelectronic,magnetic,and optoelectronic applications.展开更多
Organic spintronics refers to control spin dependent transport through organic materials.In the last two decades,extraordinary development has been achieved for organic-spintronics.A series of theoretical and experime...Organic spintronics refers to control spin dependent transport through organic materials.In the last two decades,extraordinary development has been achieved for organic-spintronics.A series of theoretical and experimental studies have been done to reveal the mechanisms of spin dependent transport properties.The theoretical analysis is based on the non-equilibrium Green's function formalism provides a mathematical framework for solving the transmission coefficients in the Landauer formula from atomistic first principles without any phenomenological parameters.In this article,we provide a brief theoretical review on organic spintronics devices and device physics therein.展开更多
A coherent nonlinear coupling between the charge and spin dynamics of electrons results in the rectification of microwaves,which is enhanced through resonant magnetization dynamics such as ferromagnetic resonance.This...A coherent nonlinear coupling between the charge and spin dynamics of electrons results in the rectification of microwaves,which is enhanced through resonant magnetization dynamics such as ferromagnetic resonance.This property,known as the spin rectification effect,enables the spin dynamics within a material to be electrically detected with a high sensitivity.Techniques utilizing this property have been widely used to study the magnetization dynamics of various ferromagnetic materials and structures in the past decade.Additionally,the coherent nature of spin rectification opens the door for spintronic devices to be used in phase-resolved microwave sensing techniques.In this work we review the physics of spin rectification and its applications in several interesting topics of magnetism and spintronics.展开更多
基金Project(10475069) supported by the National Natural Science Foundation of China
文摘Nanocrystalline nonferrous metals (Cu, Al, and Ag) were synthesized by flow-levitation-molding method. The microstructure of the as-prepared nanocrystalline metals was characterized by XRD and FESEM. The microhardness and electrical resistivity were tested by the HMV-2 type Microhardness Tester and 6157 type Electrometer, respectively. The synthesis process was also studied. The results show that the spheriform particles in nanocrystalline metals have average grain size of 20-30 nm. The relative density of nanocrystalline Cu, Al, and Ag are 95.1%, 98.1% and 98.3%, respectively. The microhardness of nanocrystalline Cu, Al and Ag are 2.01, 2.11 and 1.26 GPa respectively, which are larger than those of their coarse-grained counterparts by the factor of 4.5, 14, and 2.5, respectively. The electrical resistivity of nanocrystalline Cu at room temperature is 1.5×10-7 Ω·m, which is higher than coarse-grained Cu by a factor of 7.5. The pressure is the predominant factor influencing the density of the as-prepared nanocrystalline nonferrous metals.
基金supported by the National Key Technology Research&Development Program of China(2014BAL02B02)the National Natural Science Foundation of China(51578397)~~
文摘The anaerobic digestion of sludge has recently received increased interest because of the potential to transform organic matter into methane‐rich biogas. However, digested sludge, the residue produced in that process, still contains high levels of heavy metals and other harmful substances that might make traditional disposal difficult. We have devised a facile method of converting digested sludge into a mesoporous material that acts as an effective and stable heterogeneous catalyst for the photo‐Fenton reaction. A comparison of the removal of rhodamine B under different conditions showed that FAS‐1‐350, which was synthesized by mixing the digested sludge with a 1 mol/L（NH4）2Fe（SO4）2 solution followed by calcination at 350 °C, exhibited the best catalytic activity owing to its faster reaction rate and lower degree of Fe leaching. The results indicate that Fe^（2＋）‐loaded catalysts have significant potential to act as stable and efficient heterogeneous promoters for the photo‐Fenton reaction, with better performance than Fe^3＋‐loaded catalysts because the Fe（II）/Fe（III）compounds formed in the calcination process are necessary to sustain the Fenton reaction. This protocol provides an alternative, environmentally friendly method of reusing digested sludge and demonstrates an easily synthesized mesoporous material that effectively degrades azo dyes.
基金financially supported by the National Key Research and Development Program of China (2017YFA0207500)the National Natural Science Foundation of China (61622406, 61571415 and 51502283)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (XDB30000000)Beijing Academy of Quantum Information Sciences (Y18G04)
文摘Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage.Herein,we report the coexistence of ferroelectricity and ferromagnetism in two-dimensional Fedoped In2Se3(Fe0.16In1.84Se3,FIS).The Fe atoms were doped at the In atom sites and the Fe content is^3.22%according to the experiments.Our first-principles calculation based on the density-functional theory predicts a magnetic moment of 5μB per Fe atom when Fe substitutes In sites in In2Se3.The theoretical prediction was further confirmed experimentally by magnetic measurement.The results indicate that pure In2Se3 is diamagnetic,whereas FIS exhibits ferromagnetic behavior with a parallel anisotropy at 2 K and a Curie temperature of^8 K.Furthermore,the sample maintains stable room-temperature ferroelectricity in piezoresponse force microscopy(PFM)measurement after the introduction of Fe atom into the ferroelectric In2Se3 nanoflakes.The findings indicate that the layered Fe0.16In1.84Se3 materials have potential in future nanoelectronic,magnetic,and optoelectronic applications.
基金supported by the State Key Project of Fundamental Research of the Ministry of Science and Technology(Grant No. 2010CB934400)the National Natural Science Foundation of China (Grant Nos.11104338,10934099,and 51021061)+1 种基金the International Collaborative Research Programs between NSFC and EPSRC of the United Kingdom(Grant No.10911130234)between NSFC and ANR of France(Grant No.F040803)
文摘Organic spintronics refers to control spin dependent transport through organic materials.In the last two decades,extraordinary development has been achieved for organic-spintronics.A series of theoretical and experimental studies have been done to reveal the mechanisms of spin dependent transport properties.The theoretical analysis is based on the non-equilibrium Green's function formalism provides a mathematical framework for solving the transmission coefficients in the Landauer formula from atomistic first principles without any phenomenological parameters.In this article,we provide a brief theoretical review on organic spintronics devices and device physics therein.
基金supported by NSERC,CFI,URGPthe National Natural Science Foundation of China(Oversea Scholar Collaborative Research Grant No.11128408)
文摘A coherent nonlinear coupling between the charge and spin dynamics of electrons results in the rectification of microwaves,which is enhanced through resonant magnetization dynamics such as ferromagnetic resonance.This property,known as the spin rectification effect,enables the spin dynamics within a material to be electrically detected with a high sensitivity.Techniques utilizing this property have been widely used to study the magnetization dynamics of various ferromagnetic materials and structures in the past decade.Additionally,the coherent nature of spin rectification opens the door for spintronic devices to be used in phase-resolved microwave sensing techniques.In this work we review the physics of spin rectification and its applications in several interesting topics of magnetism and spintronics.
