Tourism English Major students’English communicative ability is very important for students’to promote professional skills.It is necessary for students to improve the commnunicative ability and It is one of the teac...Tourism English Major students’English communicative ability is very important for students’to promote professional skills.It is necessary for students to improve the commnunicative ability and It is one of the teachers’main tasks to cultivate students’communicative ability.展开更多
The oxygen-containing compounds in Fischer Tropsch synthetic oil greatly affect the downstream deep processing of hydrocarbons,and effective removal is required.Com-pared to traditional removal technologies such as hy...The oxygen-containing compounds in Fischer Tropsch synthetic oil greatly affect the downstream deep processing of hydrocarbons,and effective removal is required.Com-pared to traditional removal technologies such as hydrogenation deoxygenation,solvent extraction,and extraction distillation,adsorption deoxygenation technology has the advantages of low cost,mild operating conditions,easy removal and recovery,and mini-mal impact on oil quality.Therefore,adsorption deoxygenation technology has devel-oped rapidly in various removal processes and has become a research hotspot in the cur-rent Fischer Tropsch oil deoxygenation.Adsorbents are the core of adsorption deoxygen-ation technology.Therefore,this article briefly introduces the adsorption mechanism and summarizes the research progress of adsorbents widely used in recent years,such as silica gel,alumina,molecular sieves,and metal organic frameworks,in adsorbing oxygen-containing compounds in Fischer Tropsch synthetic oils.And provide reference sugges-tions for further adsorption and deoxygenation directions in the future.展开更多
The geometric structures,electronic absorption spectrum,and thermodynamic pro-perties of 3-(4-N-maleimido)-phenyl-2,4-dihydro-2H-1,3-benzoxazine molecule were studied at the B3LYP/6-311+G* level by density functio...The geometric structures,electronic absorption spectrum,and thermodynamic pro-perties of 3-(4-N-maleimido)-phenyl-2,4-dihydro-2H-1,3-benzoxazine molecule were studied at the B3LYP/6-311+G* level by density functional theory.The results show that three rings of this molecule are in different planes.In gas,absorption wavelength of the lowest energy excitation was obtained at 503 nm,and solvents made it blue-shifted by 3-7 nm,both corresponding to the electron transition of HOMO → LUMO.At 298.15 K,the standard molar formed enthalpy and free energy of the title compound molecule were-549.43 and-273.37 kJ·mol-1,respectively.展开更多
With the help of this software, the students have aroused the inner motivation of their own learning, and the enthusiasm of learning has been aroused by the use of cloud classes. I find English courses more and more i...With the help of this software, the students have aroused the inner motivation of their own learning, and the enthusiasm of learning has been aroused by the use of cloud classes. I find English courses more and more interesting.展开更多
Regional economy is the foundation for the development of the regional logistics and regional logistics as the support of the regional economic development, both interdependence, coordinated development, become the im...Regional economy is the foundation for the development of the regional logistics and regional logistics as the support of the regional economic development, both interdependence, coordinated development, become the important factor of regional economic sus-tained and rapid development. This article selects relevant statistical data from 2002 to 2011 in Sichuan province were analyzed, and the quantitative mathematical model was established based on principal component analysis (pca), and through the model for comprehensive evaluation of regional logistics caoability of Sichuan orovince.展开更多
Chemical disorder on the surface and lattice strain in GaN implanted by Fe^(10+)ions are investigated.In this study,3-MeV Fe^(10+)ions fluence ranges from 1×10^(13)ions/cm^(2)to 5×10^(15)ions/cm^(2)at room t...Chemical disorder on the surface and lattice strain in GaN implanted by Fe^(10+)ions are investigated.In this study,3-MeV Fe^(10+)ions fluence ranges from 1×10^(13)ions/cm^(2)to 5×10^(15)ions/cm^(2)at room temperature.X-ray photoelectron spectroscopy,high-resolution x-ray diffraction,and high-resolution transmission electron microscopy were used to characterize lattice disorder.The transition of Ga-N bonds to oxynitride bonding is caused by ion sputtering.The change of tensile strain out-of-plane with fluence was measured.Lattice disorder due to the formation of stacking faults prefers to occur on the basal plane.展开更多
Combined the purpose and requirements of security and stability economic operations of the smart grid, a more comprehensive, risk indicator system of smart grid is established from five aspects of the smart grid strat...Combined the purpose and requirements of security and stability economic operations of the smart grid, a more comprehensive, risk indicator system of smart grid is established from five aspects of the smart grid strategic risk, external risk, financial risk, compliance risk, operational risks. On this basis, it is conducted smart grid risk assessments by integrated of the use of Borda sequence value method of the original risk matrix and AHP (hierarchical analysis method), in order to assess risk facing the smart grid and enterprise development more comprehensively, objectively and systematically and conveniently, and prompt companies continue to reduce risk, improve economic efficiency, continuously improve the targeted improvement measures and continue to improve the level of grid development.展开更多
Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of...Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.展开更多
The symmetry of the in-group particles, which are of three-generation fermions, and the “out-group” ones, which are not admitted by three-generation fermions, is discussed. It was found that the “out-group” antipa...The symmetry of the in-group particles, which are of three-generation fermions, and the “out-group” ones, which are not admitted by three-generation fermions, is discussed. It was found that the “out-group” antiparticles of Bose type, which came into being because of CP ( charge Conjugation-Parity conservation) violation in the early universe and became heavier due to the phase transformation from low temperature to high temperature, are the supersymmetric companions of the in-group particles of Fermi type. The ratio of the number density of photons to that of protons calculated with Planck distribution method is about 0.61× 10^10, which is close to the observed value ( about 10^10) available in literature. A theoretical analysis of the structure of a photon suggests that the photon has a quark-gluon structure, which is consistent with the experimental result reported in literature. As the lightest particle in the supersymmetric companions, the calculated mass of a neutralino is 320 GeV. The so-called “vast area of desert” in mass scale appears to be the supersymmetry area of the three-generation particles, and “neutralinos” are the source of the moving of galaxies and the dark matter of non-baryons.展开更多
This paper analyzes the origin, status, changes and characteristics of theautomotive electromechanical maintenance skills competition in China,and presents the developing trend in the future.
In fast-developing China,all courses in college need to take ideological and political education into teaching plan,this paper talks about the combining ideological and political education with English-Chinese transla...In fast-developing China,all courses in college need to take ideological and political education into teaching plan,this paper talks about the combining ideological and political education with English-Chinese translation teaching.Starting with analyzing the current situation and the necessities,this paper points out three basics for the combining:national confidence,culture confidence and keeping pace with the times.In the end,this paper points out some requirements for colleges,for departments,for teachers and for teaching methodologies.展开更多
By explaining the meaning of"Humanism"and how it influenced the foreign language teaching, this essay discusses about the basic features of the Humanism Approach as well as what we should pay attention to wh...By explaining the meaning of"Humanism"and how it influenced the foreign language teaching, this essay discusses about the basic features of the Humanism Approach as well as what we should pay attention to when using this approach in practical foreign language teaching.展开更多
Wildly studied by scholars in foreign language teaching field,the variability and systemacity of interlanguage are controversial.This paper analyzes and discusses the variability and systemacity of interlanguage respe...Wildly studied by scholars in foreign language teaching field,the variability and systemacity of interlanguage are controversial.This paper analyzes and discusses the variability and systemacity of interlanguage respectively,and strives to find the relationship between them in order to promote the development of second language acquisition.展开更多
With the vigorous development of Internet of Things(IoT)technology,the demand for communication and data exchange between different types of IoT devices is increasing day by day.To solve the problems of diversity and ...With the vigorous development of Internet of Things(IoT)technology,the demand for communication and data exchange between different types of IoT devices is increasing day by day.To solve the problems of diversity and complexity of communication protocols between devices,this paper proposes a design scheme of a multi-connector IoT central gateway based on Raspberry Pi and Docker.Through the research and application of related technologies,by integrating multiple communication interfaces and utilizing containerization technology,an efficient,flexible,and scalable IoT central gateway has been realized,which can support the connection and data interaction of multiple communication protocols and provide strong support for the stable operation and development of the IoT system.展开更多
Charge transport properties of F, OH, OCH3, SH and SCH3-substituted tetra- benz[a,c,h,j]- anthracene derivative molecules have been investigated theoretically at the B3LYP/6-31G** level using Marcus theory. The resu...Charge transport properties of F, OH, OCH3, SH and SCH3-substituted tetra- benz[a,c,h,j]- anthracene derivative molecules have been investigated theoretically at the B3LYP/6-31G** level using Marcus theory. The results showed that at 300 K, the hole or electron transport capability of F or SH-substituted molecules was better obviously than that of OH or OCH3-substituted molecules, The electron transport capability of SCH3-substituted and F or SH-substituted molecules was superior to their hole transport capability, respectively. F, SH or SCH3-substituted tetrabenz[a,c,h,j]-anthracene derivative molecules can be used as electron transport materials.展开更多
A nano-twinned microstructure was found in amorphous SiC after high-temperature annealing.Grazing incidence x-ray diffraction,high-resolution transmission electron microscopy,and electron diffraction were performed to...A nano-twinned microstructure was found in amorphous SiC after high-temperature annealing.Grazing incidence x-ray diffraction,high-resolution transmission electron microscopy,and electron diffraction were performed to characterize the microstructure and phase transition in the recrystallization layer.After 1500℃or 2-h annealing,3C-SiC grains and numerous stacking faults on the{111}planes were visible.Some 3C-SiC grains have nano-twinned structure with{011}planes.Between the nano-twinned 3C-SiC grains,there is a stacking fault,indicating that the formation mechanisms of the nano-twinned structure are related to the disorder of Si atoms.The increase in the twin thickness with increasing annealing temperature demonstrates that the nano-twinned structure can sink for lattice defects,in order to improve the radiation tolerance of SiC.展开更多
The recyclable and stable ZnFe_(2)O_(4) small particle decorated one‐dimensional perylene diimide(PDI)S‐scheme heterojunction(1D PDI/ZnFe_(2)O_(4))is prepared by the hydrochloric acid‐mediated(HCl‐mediated)strateg...The recyclable and stable ZnFe_(2)O_(4) small particle decorated one‐dimensional perylene diimide(PDI)S‐scheme heterojunction(1D PDI/ZnFe_(2)O_(4))is prepared by the hydrochloric acid‐mediated(HCl‐mediated)strategy,interestingly,the morphology of the 1D PDI/ZnFe_(2)O_(4) can also be effectively regulated by HCl‐mediated process,the existence of HCl can regulate PDI into a uniform rod structure,while the co‐existence of HCl and PDI can limit ZnFe_(2)O_(4) to become the uniform small particles.More importantly,based on the 1D rod structure of PDI and the small size effect of ZnFe_(2)O_(4),carriers can migrate to the surface more easily,which can improve the photocatalytic activity.Meanwhile,due to the appropriate energy level structure,the S‐scheme heterojunction structure is formed between PDI and ZnFe_(2)O_(4),which eliminates meaningless photo‐generated charge carriers through recombination and introduces strong redox to further enhance the photodegradation effect,thereby,1D PDI/ZnFe_(2)O_(4) exhibits excellent photocatalytic ability,under the visible light irradiation,the degradation rate of tetracycline(TC)with 1D PDI/ZnFe_(2)O_(4)(66.67%)is 9.18 times that with PDI(7.26%)and 9.73 times that with ZnFe_(2)O_(4)(6.85%).This work proposes new ideas for the assembly of magnetic organic‐inorganic S‐scheme heterojunction photocatalysts.展开更多
Artificial photosynthesis of valuable chemicals from CO_(2)is a potential way to achieve sustainable carbon cycle.The CO_(2)conversion activity is still inhibited by the sluggish charge kinetics and poor CO_(2)activat...Artificial photosynthesis of valuable chemicals from CO_(2)is a potential way to achieve sustainable carbon cycle.The CO_(2)conversion activity is still inhibited by the sluggish charge kinetics and poor CO_(2)activation.Herein,Ag nanoparticles coupled Bi OBr have been constructed by in-situ photoreduction strategy.The crafting of interface between Ag nanoparticles and Bi OBr nanosheets,achieving an ultra-fast charge transfer.The Bi OBr semiconductor excited electrons and plasmonic Ag nanoparticles generated high-energy hot electrons synchronous accelerates the C=O double bond activation.Thus,the optimized Ag/BiOBr-2 heterostructure shows excellent CO_(2)photoreduction activity with CO production of 133.75 and 6.83μmol/g under 5 h of 300 W Xe lamp and visible light(λ>400 nm)irradiation,which is 1.51 and 2.81 folds versus the pristine Bi OBr,respectively.The mechanism of CO_(2)photoreduction was in-depth understood through in-situ FT-IR spectrum and density functional theory calculations.This study provides some new perspectives into efficient photocatalytic CO_(2)reduction.展开更多
Although CO_(2)photoreduction is a promising method for solar‐to‐fuel conversion,it suffers from low charge transfer efficiency of the photocatalysts.To improve the CO_(2)photoreduction performance,introduction of e...Although CO_(2)photoreduction is a promising method for solar‐to‐fuel conversion,it suffers from low charge transfer efficiency of the photocatalysts.To improve the CO_(2)photoreduction performance,introduction of electron‐accumulated materials on the photocatalyst surface is considered an effective method.In this study,the Bi_(19)S_(27)Br_(3)/BiOBr composites were designed and synthesized.The Bi19S27Br3 nanorod in this photocatalytic system acts as an electron‐accumulated active site for extracting the photogenerated electrons on the BiOBr surface and for effectively activating the CO2 molecules.As a result,Bi_(19)S_(27)Br_(3)/BiOBr composites exhibit the higher charge carrier transfer efficiency and further improves the CO_(2)photoreduction performance relative to that of pure Bi_(19)S_(27)Br_(3)and BiOBr.The rate of CO formation using Bi_(19)S_(27)Br_(3)/BiOBr‐5 is about 8.74 and 2.40 times that using Bi_(19)S_(27)Br_(3)and BiOBr,respectively.This work provides new insights for the application of Bi_(19)S_(27)Br_(3)as an electron‐accumulating site for achieving high photocatalytic CO2 reduction performance in the future.展开更多
The coupled longitudinal-transverse waves propagating freely along a viscoelastic cable was studied. The frequency-spectrum equation governing propagating waves and the formulations of the phase velocities and the gro...The coupled longitudinal-transverse waves propagating freely along a viscoelastic cable was studied. The frequency-spectrum equation governing propagating waves and the formulations of the phase velocities and the group velocities characterizing propagating waves were derived. The effects of viscosity parameters on the phase velocities and the group velocities were investigated with numerical simulation. The analyses show that viscosity has a strong influence on the phase velocity and the group velocity of propagating waves and attenuation waves for longitudinal-dominant waves, but the phase velocities of propagating waves of transverse-dominant waves do not change with viscosity.展开更多
文摘Tourism English Major students’English communicative ability is very important for students’to promote professional skills.It is necessary for students to improve the commnunicative ability and It is one of the teachers’main tasks to cultivate students’communicative ability.
文摘The oxygen-containing compounds in Fischer Tropsch synthetic oil greatly affect the downstream deep processing of hydrocarbons,and effective removal is required.Com-pared to traditional removal technologies such as hydrogenation deoxygenation,solvent extraction,and extraction distillation,adsorption deoxygenation technology has the advantages of low cost,mild operating conditions,easy removal and recovery,and mini-mal impact on oil quality.Therefore,adsorption deoxygenation technology has devel-oped rapidly in various removal processes and has become a research hotspot in the cur-rent Fischer Tropsch oil deoxygenation.Adsorbents are the core of adsorption deoxygen-ation technology.Therefore,this article briefly introduces the adsorption mechanism and summarizes the research progress of adsorbents widely used in recent years,such as silica gel,alumina,molecular sieves,and metal organic frameworks,in adsorbing oxygen-containing compounds in Fischer Tropsch synthetic oils.And provide reference sugges-tions for further adsorption and deoxygenation directions in the future.
基金Sponsored by the Supporting Project of Sichuan Province Key Technology Support Program (2011ZG0247)Sichuan Province Education Office Natural Science Foundation (10ZC080)
文摘The geometric structures,electronic absorption spectrum,and thermodynamic pro-perties of 3-(4-N-maleimido)-phenyl-2,4-dihydro-2H-1,3-benzoxazine molecule were studied at the B3LYP/6-311+G* level by density functional theory.The results show that three rings of this molecule are in different planes.In gas,absorption wavelength of the lowest energy excitation was obtained at 503 nm,and solvents made it blue-shifted by 3-7 nm,both corresponding to the electron transition of HOMO → LUMO.At 298.15 K,the standard molar formed enthalpy and free energy of the title compound molecule were-549.43 and-273.37 kJ·mol-1,respectively.
文摘With the help of this software, the students have aroused the inner motivation of their own learning, and the enthusiasm of learning has been aroused by the use of cloud classes. I find English courses more and more interesting.
文摘Regional economy is the foundation for the development of the regional logistics and regional logistics as the support of the regional economic development, both interdependence, coordinated development, become the important factor of regional economic sus-tained and rapid development. This article selects relevant statistical data from 2002 to 2011 in Sichuan province were analyzed, and the quantitative mathematical model was established based on principal component analysis (pca), and through the model for comprehensive evaluation of regional logistics caoability of Sichuan orovince.
基金Project supported by the National Natural Science Foundation of China(Grant No.12075194)the Fund of Collage Student Innovation and Entrepreneurship Training Program(Grant No.S202010619053)。
文摘Chemical disorder on the surface and lattice strain in GaN implanted by Fe^(10+)ions are investigated.In this study,3-MeV Fe^(10+)ions fluence ranges from 1×10^(13)ions/cm^(2)to 5×10^(15)ions/cm^(2)at room temperature.X-ray photoelectron spectroscopy,high-resolution x-ray diffraction,and high-resolution transmission electron microscopy were used to characterize lattice disorder.The transition of Ga-N bonds to oxynitride bonding is caused by ion sputtering.The change of tensile strain out-of-plane with fluence was measured.Lattice disorder due to the formation of stacking faults prefers to occur on the basal plane.
文摘Combined the purpose and requirements of security and stability economic operations of the smart grid, a more comprehensive, risk indicator system of smart grid is established from five aspects of the smart grid strategic risk, external risk, financial risk, compliance risk, operational risks. On this basis, it is conducted smart grid risk assessments by integrated of the use of Borda sequence value method of the original risk matrix and AHP (hierarchical analysis method), in order to assess risk facing the smart grid and enterprise development more comprehensively, objectively and systematically and conveniently, and prompt companies continue to reduce risk, improve economic efficiency, continuously improve the targeted improvement measures and continue to improve the level of grid development.
文摘Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.
文摘The symmetry of the in-group particles, which are of three-generation fermions, and the “out-group” ones, which are not admitted by three-generation fermions, is discussed. It was found that the “out-group” antiparticles of Bose type, which came into being because of CP ( charge Conjugation-Parity conservation) violation in the early universe and became heavier due to the phase transformation from low temperature to high temperature, are the supersymmetric companions of the in-group particles of Fermi type. The ratio of the number density of photons to that of protons calculated with Planck distribution method is about 0.61× 10^10, which is close to the observed value ( about 10^10) available in literature. A theoretical analysis of the structure of a photon suggests that the photon has a quark-gluon structure, which is consistent with the experimental result reported in literature. As the lightest particle in the supersymmetric companions, the calculated mass of a neutralino is 320 GeV. The so-called “vast area of desert” in mass scale appears to be the supersymmetry area of the three-generation particles, and “neutralinos” are the source of the moving of galaxies and the dark matter of non-baryons.
文摘This paper analyzes the origin, status, changes and characteristics of theautomotive electromechanical maintenance skills competition in China,and presents the developing trend in the future.
基金funded by the project of Translation for International Communication from the Perspective of Intercultural Pragmatics(18SA0253).
文摘In fast-developing China,all courses in college need to take ideological and political education into teaching plan,this paper talks about the combining ideological and political education with English-Chinese translation teaching.Starting with analyzing the current situation and the necessities,this paper points out three basics for the combining:national confidence,culture confidence and keeping pace with the times.In the end,this paper points out some requirements for colleges,for departments,for teachers and for teaching methodologies.
文摘By explaining the meaning of"Humanism"and how it influenced the foreign language teaching, this essay discusses about the basic features of the Humanism Approach as well as what we should pay attention to when using this approach in practical foreign language teaching.
文摘Wildly studied by scholars in foreign language teaching field,the variability and systemacity of interlanguage are controversial.This paper analyzes and discusses the variability and systemacity of interlanguage respectively,and strives to find the relationship between them in order to promote the development of second language acquisition.
文摘With the vigorous development of Internet of Things(IoT)technology,the demand for communication and data exchange between different types of IoT devices is increasing day by day.To solve the problems of diversity and complexity of communication protocols between devices,this paper proposes a design scheme of a multi-connector IoT central gateway based on Raspberry Pi and Docker.Through the research and application of related technologies,by integrating multiple communication interfaces and utilizing containerization technology,an efficient,flexible,and scalable IoT central gateway has been realized,which can support the connection and data interaction of multiple communication protocols and provide strong support for the stable operation and development of the IoT system.
基金sponsored by the National Natural Science Foundation of China(No.50973076)Sichuan Provincial Scientific Program(No.2010JY0041 and 2011ZG0247)the Natural Science Program of Sichuan Provincial Education Department(No.11ZA206)
文摘Charge transport properties of F, OH, OCH3, SH and SCH3-substituted tetra- benz[a,c,h,j]- anthracene derivative molecules have been investigated theoretically at the B3LYP/6-31G** level using Marcus theory. The results showed that at 300 K, the hole or electron transport capability of F or SH-substituted molecules was better obviously than that of OH or OCH3-substituted molecules, The electron transport capability of SCH3-substituted and F or SH-substituted molecules was superior to their hole transport capability, respectively. F, SH or SCH3-substituted tetrabenz[a,c,h,j]-anthracene derivative molecules can be used as electron transport materials.
基金Project supported by the National Natural Science Foundation of China(Grant No.12075194)Sichuan Science and Technology Program(Grant No.2020ZYD055)。
文摘A nano-twinned microstructure was found in amorphous SiC after high-temperature annealing.Grazing incidence x-ray diffraction,high-resolution transmission electron microscopy,and electron diffraction were performed to characterize the microstructure and phase transition in the recrystallization layer.After 1500℃or 2-h annealing,3C-SiC grains and numerous stacking faults on the{111}planes were visible.Some 3C-SiC grains have nano-twinned structure with{011}planes.Between the nano-twinned 3C-SiC grains,there is a stacking fault,indicating that the formation mechanisms of the nano-twinned structure are related to the disorder of Si atoms.The increase in the twin thickness with increasing annealing temperature demonstrates that the nano-twinned structure can sink for lattice defects,in order to improve the radiation tolerance of SiC.
文摘The recyclable and stable ZnFe_(2)O_(4) small particle decorated one‐dimensional perylene diimide(PDI)S‐scheme heterojunction(1D PDI/ZnFe_(2)O_(4))is prepared by the hydrochloric acid‐mediated(HCl‐mediated)strategy,interestingly,the morphology of the 1D PDI/ZnFe_(2)O_(4) can also be effectively regulated by HCl‐mediated process,the existence of HCl can regulate PDI into a uniform rod structure,while the co‐existence of HCl and PDI can limit ZnFe_(2)O_(4) to become the uniform small particles.More importantly,based on the 1D rod structure of PDI and the small size effect of ZnFe_(2)O_(4),carriers can migrate to the surface more easily,which can improve the photocatalytic activity.Meanwhile,due to the appropriate energy level structure,the S‐scheme heterojunction structure is formed between PDI and ZnFe_(2)O_(4),which eliminates meaningless photo‐generated charge carriers through recombination and introduces strong redox to further enhance the photodegradation effect,thereby,1D PDI/ZnFe_(2)O_(4) exhibits excellent photocatalytic ability,under the visible light irradiation,the degradation rate of tetracycline(TC)with 1D PDI/ZnFe_(2)O_(4)(66.67%)is 9.18 times that with PDI(7.26%)and 9.73 times that with ZnFe_(2)O_(4)(6.85%).This work proposes new ideas for the assembly of magnetic organic‐inorganic S‐scheme heterojunction photocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.22108106,21878134,21576123)China Postdoctoral Science Foundation(No.2020M680065)+1 种基金Hong Kong Scholar Program(No.XJ2021021)Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province(No.KFKT2021005)。
文摘Artificial photosynthesis of valuable chemicals from CO_(2)is a potential way to achieve sustainable carbon cycle.The CO_(2)conversion activity is still inhibited by the sluggish charge kinetics and poor CO_(2)activation.Herein,Ag nanoparticles coupled Bi OBr have been constructed by in-situ photoreduction strategy.The crafting of interface between Ag nanoparticles and Bi OBr nanosheets,achieving an ultra-fast charge transfer.The Bi OBr semiconductor excited electrons and plasmonic Ag nanoparticles generated high-energy hot electrons synchronous accelerates the C=O double bond activation.Thus,the optimized Ag/BiOBr-2 heterostructure shows excellent CO_(2)photoreduction activity with CO production of 133.75 and 6.83μmol/g under 5 h of 300 W Xe lamp and visible light(λ>400 nm)irradiation,which is 1.51 and 2.81 folds versus the pristine Bi OBr,respectively.The mechanism of CO_(2)photoreduction was in-depth understood through in-situ FT-IR spectrum and density functional theory calculations.This study provides some new perspectives into efficient photocatalytic CO_(2)reduction.
文摘Although CO_(2)photoreduction is a promising method for solar‐to‐fuel conversion,it suffers from low charge transfer efficiency of the photocatalysts.To improve the CO_(2)photoreduction performance,introduction of electron‐accumulated materials on the photocatalyst surface is considered an effective method.In this study,the Bi_(19)S_(27)Br_(3)/BiOBr composites were designed and synthesized.The Bi19S27Br3 nanorod in this photocatalytic system acts as an electron‐accumulated active site for extracting the photogenerated electrons on the BiOBr surface and for effectively activating the CO2 molecules.As a result,Bi_(19)S_(27)Br_(3)/BiOBr composites exhibit the higher charge carrier transfer efficiency and further improves the CO_(2)photoreduction performance relative to that of pure Bi_(19)S_(27)Br_(3)and BiOBr.The rate of CO formation using Bi_(19)S_(27)Br_(3)/BiOBr‐5 is about 8.74 and 2.40 times that using Bi_(19)S_(27)Br_(3)and BiOBr,respectively.This work provides new insights for the application of Bi_(19)S_(27)Br_(3)as an electron‐accumulating site for achieving high photocatalytic CO2 reduction performance in the future.
文摘The coupled longitudinal-transverse waves propagating freely along a viscoelastic cable was studied. The frequency-spectrum equation governing propagating waves and the formulations of the phase velocities and the group velocities characterizing propagating waves were derived. The effects of viscosity parameters on the phase velocities and the group velocities were investigated with numerical simulation. The analyses show that viscosity has a strong influence on the phase velocity and the group velocity of propagating waves and attenuation waves for longitudinal-dominant waves, but the phase velocities of propagating waves of transverse-dominant waves do not change with viscosity.