A nanocomposite of manganese dioxide coated manganese hexacyanoferrate was synthesized by a facile co-precipitation method and tested as active electrode material for an electrochemical supercapacitor. A way called &q...A nanocomposite of manganese dioxide coated manganese hexacyanoferrate was synthesized by a facile co-precipitation method and tested as active electrode material for an electrochemical supercapacitor. A way called "Deep electro-oxidation" was used to generate manganese dioxide coated layer for stabilizing the electrode material. The structure and ingredient of the resulting MnHCF/MnO2 composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray Photoelectron Spectroscopy. Electrochemical testing showed a capacitance of 225.6 F/g at a sweep rate of 5 mV/s within a voltage range of 1.3 V, and high energy density of 37.2 Wh/kg at a current density of 0.5 A/g in galvanostatic charge/discharge cycling. It is suggested that the two different components, manganese hexacyanoferrate core and manganese dioxide shell, lead to an integrated electrochemical behavior, and an enhanced capacitor. The electrochemical testing and corresponding XPS analysis also demonstrated that the manganese coordinated by cyanide groups via nitrogen atoms in MnHCF did not get involved in the charge storage process during potential cycles.展开更多
Acetobacteraceae has garnered significant attention because of its unique properties and the broad applications of the bacterial cellulose it produces.However,unlike model strains,Acetobacteraceae have few synthetic b...Acetobacteraceae has garnered significant attention because of its unique properties and the broad applications of the bacterial cellulose it produces.However,unlike model strains,Acetobacteraceae have few synthetic biology applications because they are difficult to manipulate genetically and have insufficient genetic regulatory elements,among other factors.To address this limitation,this study characterized the fundamental properties and synthetic biology elements of three commonly used bacterial cellulose-producing strains.First,the basic characteristics of the three strains,including their cellulose film production ability,division time,antibiotic susceptibility,and plasmid features,were analyzed.Two inducible promoters(pTrc and pLux101)were subsequently characterized within the three strains.The inducibility of the pTrc promoter was relatively low across the three strains(induction ratio:1.98–6.39),whereas the pLux101 promoter demonstrated a significantly greater level of inducibility within the three strains(induction ratio:87.28–216.71).Finally,through gene knockout experiments,this study identified four genes essential for bacterial cellulose film production in the genome of the Gluconacetobacter hansenii ATCC 5358 strain.This study not only enriches the library of synthetic biology elements in nonmodel strains,but also lays the foundation for the synthetic biology applications of Acetobacteraceae.展开更多
Quantum Science Satellite is one of the first five space science missions, slated for launch in the framework of Chinese Academy of Sciences(CAS) Strategic Priority Research Program on space science. The project aims ...Quantum Science Satellite is one of the first five space science missions, slated for launch in the framework of Chinese Academy of Sciences(CAS) Strategic Priority Research Program on space science. The project aims to establish a space platform with long-distance satellite and ground quantum channel, and carry out a series of tests about fundamental quantum principles and protocols in space-based large scale. The satellite will be launched at Jiuquan and on orbit for 2 years. The orbit will be circular and Sun-synchronous with an altitude of 600 km. It crosses the descending node at 00:00 LT. The satellite is under early prototype development currently.展开更多
Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
By using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved at a global scale. The Quantum Experiment Science Satellite(QUESS) in China, also called Micius, one of...By using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved at a global scale. The Quantum Experiment Science Satellite(QUESS) in China, also called Micius, one of the scientific satellite programs in the Strategic Priority Program on space science, the Chinese Academy of Sciences, was launched on 16 August 2016. There are totally 4 scientific payloads. We give a brief overview of the quantum experiment science satellite project and present most recent science results. The main scientific goal of the quantum experiment science satellite was achieved in 2017. Here, we introduce the latest achievements in satellite-based quantum communication and large-scale tests of quantum foundations obtained by Micius.展开更多
The precursor powders of LuAG∶Ce3+ transparent ceramics were synthesized by solvo-thermal method.The crystal structure and morphology of powders were analyzed by means of Fourier transform infra-red spectroscopy,X-ra...The precursor powders of LuAG∶Ce3+ transparent ceramics were synthesized by solvo-thermal method.The crystal structure and morphology of powders were analyzed by means of Fourier transform infra-red spectroscopy,X-ray diffraction and scanning electron microscopy.The precursor powders were sintered into transparent ceramics in vacuum and then in nitrogen without any additive.The surface morphology of the transparent unpolished ceramics was characterized using scanning electron microscopy.Some factors that affect the transparency of ceramics were discussed.The UV-Vis fluorescence excitation and emission spectra of LuAG∶Ce3+ transparent ceramics were measured.The vacuum ultraviolet spectra of transparent ceramics were investigated using the synchrotron radiation as the excitation source.The excitation mechanism of Ce3+ was discussed at different excitation wavelength.展开更多
The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-ba...The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-based quantum entanglement distribution,ground-to-satellite quantum teleportation,and satellite relayed intercontinental quantum network,were achieved in 2017.As a starting point,the Micius satellite has become a platform for quantum science experiments at the space scale.Here,we introduce the latest experimental achievements(in 2018–2020)based on the Micius satellite.展开更多
Graphene, the thinnest and hardest nano-material in the world, is non-toxic, sustainable and with minimal environmental footprint. As one of the most important carbon materials, it is composed of a monolayer of carbon...Graphene, the thinnest and hardest nano-material in the world, is non-toxic, sustainable and with minimal environmental footprint. As one of the most important carbon materials, it is composed of a monolayer of carbon atoms with a honeycomb structure. Nowadays, scientists have tried to use it in the biomedicine subject because of its superior physical and chemical properties and excellent biocompatibility.展开更多
The high theoretical capacity and low discharge potential of silicon have attracted much attention on Si-based anodes. Herein, hollow porous SiO2 nanocubes have been prepared via a two-step hard-template process and e...The high theoretical capacity and low discharge potential of silicon have attracted much attention on Si-based anodes. Herein, hollow porous SiO2 nanocubes have been prepared via a two-step hard-template process and evaluated as electrode materials for lithium-ion batteries. The hollow porous SiO2 nanocubes exhibited a reversible capacity of 919 mAh/g over 30 cycles. The excellent property could be attributed to the unique hollow nanostructure with large volume interior and numerous crevices in the shell, which could accommodate the volume change and alleviate the structural strain during Li ions insertion and extraction, as well as allow rapid access of Li ions during charge/discharge cycling. It is found that the formation of irreversible or reversible lithium silicates in the anodes determines the capacity of a deep-cycle battery, fast transportation of Li ions in hollow porous SiO2 nanocubes is preferred to form Li2O and Si, contributing to the high reversible capacity. The hollow porous SiO2 nanocubes have great potential applications for Li-ion batteries due to their remarkable electrochemical performance and low cost.展开更多
ZnO thin films with varying Ta concentrations were fabricated through magnetron sputtering.The crystallinity and surface morphology of the ZnO films are significantly influenced by the incorporation of Ta,as evidenced...ZnO thin films with varying Ta concentrations were fabricated through magnetron sputtering.The crystallinity and surface morphology of the ZnO films are significantly influenced by the incorporation of Ta,as evidenced by the X-ray diffraction and scanning electron microscopy results.The lattice constants,as determined by X-ray diffraction,contradict the disparity in Ta and Zn ion radii,which is attributed to the impact of interstitial defects.This inconsistency introduces variations in carrier concentration in this experiment compared with prior studies.Subsequent exploration of the luminescent characteristics and emission mechanism of defect levels in Ta-doped ZnO films was conducted through photoluminescence.Furthermore,the factors influencing the bandgap are discussed.展开更多
文摘A nanocomposite of manganese dioxide coated manganese hexacyanoferrate was synthesized by a facile co-precipitation method and tested as active electrode material for an electrochemical supercapacitor. A way called "Deep electro-oxidation" was used to generate manganese dioxide coated layer for stabilizing the electrode material. The structure and ingredient of the resulting MnHCF/MnO2 composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray Photoelectron Spectroscopy. Electrochemical testing showed a capacitance of 225.6 F/g at a sweep rate of 5 mV/s within a voltage range of 1.3 V, and high energy density of 37.2 Wh/kg at a current density of 0.5 A/g in galvanostatic charge/discharge cycling. It is suggested that the two different components, manganese hexacyanoferrate core and manganese dioxide shell, lead to an integrated electrochemical behavior, and an enhanced capacitor. The electrochemical testing and corresponding XPS analysis also demonstrated that the manganese coordinated by cyanide groups via nitrogen atoms in MnHCF did not get involved in the charge storage process during potential cycles.
文摘Acetobacteraceae has garnered significant attention because of its unique properties and the broad applications of the bacterial cellulose it produces.However,unlike model strains,Acetobacteraceae have few synthetic biology applications because they are difficult to manipulate genetically and have insufficient genetic regulatory elements,among other factors.To address this limitation,this study characterized the fundamental properties and synthetic biology elements of three commonly used bacterial cellulose-producing strains.First,the basic characteristics of the three strains,including their cellulose film production ability,division time,antibiotic susceptibility,and plasmid features,were analyzed.Two inducible promoters(pTrc and pLux101)were subsequently characterized within the three strains.The inducibility of the pTrc promoter was relatively low across the three strains(induction ratio:1.98–6.39),whereas the pLux101 promoter demonstrated a significantly greater level of inducibility within the three strains(induction ratio:87.28–216.71).Finally,through gene knockout experiments,this study identified four genes essential for bacterial cellulose film production in the genome of the Gluconacetobacter hansenii ATCC 5358 strain.This study not only enriches the library of synthetic biology elements in nonmodel strains,but also lays the foundation for the synthetic biology applications of Acetobacteraceae.
基金Supported by National Key Basic Research Program of China（973 Program）（2006CB922004） National Natural Science Foundation of China（60904033 60774098）+1 种基金 the Chinese Postdoctoral Science Foundation（20100470848） K.C.Wong Education Foundation HongKong
文摘Quantum Science Satellite is one of the first five space science missions, slated for launch in the framework of Chinese Academy of Sciences(CAS) Strategic Priority Research Program on space science. The project aims to establish a space platform with long-distance satellite and ground quantum channel, and carry out a series of tests about fundamental quantum principles and protocols in space-based large scale. The satellite will be launched at Jiuquan and on orbit for 2 years. The orbit will be circular and Sun-synchronous with an altitude of 600 km. It crosses the descending node at 00:00 LT. The satellite is under early prototype development currently.
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
文摘By using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved at a global scale. The Quantum Experiment Science Satellite(QUESS) in China, also called Micius, one of the scientific satellite programs in the Strategic Priority Program on space science, the Chinese Academy of Sciences, was launched on 16 August 2016. There are totally 4 scientific payloads. We give a brief overview of the quantum experiment science satellite project and present most recent science results. The main scientific goal of the quantum experiment science satellite was achieved in 2017. Here, we introduce the latest achievements in satellite-based quantum communication and large-scale tests of quantum foundations obtained by Micius.
基金Project supported by National Nature Science Foundation of China(10774140)Knowledge Innovation Project of The Chinese Academy of Sciences(KJCX2-YW-M11)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education(20060358054)Special Foundation for Talents of Anhui Province,China(2007Z021)
文摘The precursor powders of LuAG∶Ce3+ transparent ceramics were synthesized by solvo-thermal method.The crystal structure and morphology of powders were analyzed by means of Fourier transform infra-red spectroscopy,X-ray diffraction and scanning electron microscopy.The precursor powders were sintered into transparent ceramics in vacuum and then in nitrogen without any additive.The surface morphology of the transparent unpolished ceramics was characterized using scanning electron microscopy.Some factors that affect the transparency of ceramics were discussed.The UV-Vis fluorescence excitation and emission spectra of LuAG∶Ce3+ transparent ceramics were measured.The vacuum ultraviolet spectra of transparent ceramics were investigated using the synchrotron radiation as the excitation source.The excitation mechanism of Ce3+ was discussed at different excitation wavelength.
文摘The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-based quantum entanglement distribution,ground-to-satellite quantum teleportation,and satellite relayed intercontinental quantum network,were achieved in 2017.As a starting point,the Micius satellite has become a platform for quantum science experiments at the space scale.Here,we introduce the latest experimental achievements(in 2018–2020)based on the Micius satellite.
文摘Graphene, the thinnest and hardest nano-material in the world, is non-toxic, sustainable and with minimal environmental footprint. As one of the most important carbon materials, it is composed of a monolayer of carbon atoms with a honeycomb structure. Nowadays, scientists have tried to use it in the biomedicine subject because of its superior physical and chemical properties and excellent biocompatibility.
文摘The high theoretical capacity and low discharge potential of silicon have attracted much attention on Si-based anodes. Herein, hollow porous SiO2 nanocubes have been prepared via a two-step hard-template process and evaluated as electrode materials for lithium-ion batteries. The hollow porous SiO2 nanocubes exhibited a reversible capacity of 919 mAh/g over 30 cycles. The excellent property could be attributed to the unique hollow nanostructure with large volume interior and numerous crevices in the shell, which could accommodate the volume change and alleviate the structural strain during Li ions insertion and extraction, as well as allow rapid access of Li ions during charge/discharge cycling. It is found that the formation of irreversible or reversible lithium silicates in the anodes determines the capacity of a deep-cycle battery, fast transportation of Li ions in hollow porous SiO2 nanocubes is preferred to form Li2O and Si, contributing to the high reversible capacity. The hollow porous SiO2 nanocubes have great potential applications for Li-ion batteries due to their remarkable electrochemical performance and low cost.
基金supported by the National Natural Science Foundation of China(61774140).
文摘ZnO thin films with varying Ta concentrations were fabricated through magnetron sputtering.The crystallinity and surface morphology of the ZnO films are significantly influenced by the incorporation of Ta,as evidenced by the X-ray diffraction and scanning electron microscopy results.The lattice constants,as determined by X-ray diffraction,contradict the disparity in Ta and Zn ion radii,which is attributed to the impact of interstitial defects.This inconsistency introduces variations in carrier concentration in this experiment compared with prior studies.Subsequent exploration of the luminescent characteristics and emission mechanism of defect levels in Ta-doped ZnO films was conducted through photoluminescence.Furthermore,the factors influencing the bandgap are discussed.
