Fe(Ⅲ)has been proved to be a more eff ective oxidant than dissolved oxygen at ambient temperature,however,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so far.In this paper,in-situ electr...Fe(Ⅲ)has been proved to be a more eff ective oxidant than dissolved oxygen at ambient temperature,however,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so far.In this paper,in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment.The results illustrated that increasing Fe(Ⅲ)concentrations led to raising in redox potential of the solution,and decreased passivation of pyrite caused by deposition of elemental sulfur.Reduction of Fe(Ⅲ)at pyrite surface was a fast reaction with low activation energy,it was only slightly promoted by rising temperatures.While,the oxidation rate of pyrite at all investigated Fe(Ⅲ)concentrations increased obviously with rising temperatures,the anodic reaction was the rate-limiting step in the overall reaction.Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(Ⅲ)concentration was increased from 0.05 to 0.50 g/L,showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(Ⅲ)concentrations,while,it gradually turned to be diffusion control with increasing Fe(Ⅲ)concentrations.展开更多
Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natura...Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natural rock.Extrusion free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature sintering.In this study,we attempted to use the EFF technology to fabricate artificial rock specimens.The results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain impact.The specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural rocks.The density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,respectively.It is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and gneiss.However,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation.展开更多
The effective connection of 1050 Al and AZ31 Mg was realized by magnetic pulse welding.The maximum tensile-shear force of the dissimilar Al/Mg metal lap joint reached 97%of that of the 1050 Al alloy base material by o...The effective connection of 1050 Al and AZ31 Mg was realized by magnetic pulse welding.The maximum tensile-shear force of the dissimilar Al/Mg metal lap joint reached 97%of that of the 1050 Al alloy base material by optimizing the process parameters.The microstructure of dissimilar Al/Mg welded joints was analysed by Scanning Electron Microscope(SEM),Energy Dispersive Spectrometer(EDS)and Electron Backscattered Diffraction(EBSD).The results show that the key to obtaining high shear strength of Al/Mg dissimilar metal joints is mainly due to the following two reasons.On the one hand,grain refinement and element interdiffusion occur at the interface.On the other hand,no intermetallic compounds are formed at the interface.展开更多
Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water ele...Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water electrolysis.However,highly effective and inexpensive earth-abundant materials are sought after to replace the noble metal-based electrocatalysts currently in use.Recently,metal-organic frameworks(MOFs)and carbon-based MOF derivatives have attracted considerable attention as efficient catalysts due to their exceedingly tunable morphologies,structures,compositions,and functionalization.Here,we report two-dimensional(2D)MOF/MOF derivative coupled arrays on nickel foam as binder-free bifunctional ORR/OER catalysts with enhanced electrocatalytic activity and stability.Their remarkable electrochemical properties are primarily attributed to fully exposed active sites and facilitated charge-transfer kinetics.The coupled and hierarchical nanosheet arrays produced via our growth-pyrolysis-regrowth strategy offer promise in the development of highly active electrodes for energy-related electrochemical devices.展开更多
Flavonols and other phenylpropanoids protect plants from biotic and abiotic stress and are dietarily desirable because of their health-promoting properties.The ability to develop new potatoes(Solanum tuberosum)with op...Flavonols and other phenylpropanoids protect plants from biotic and abiotic stress and are dietarily desirable because of their health-promoting properties.The ability to develop new potatoes(Solanum tuberosum)with optimal types and amounts of phenylpropanoids is limited by lack of knowledge about the regulatory mechanisms.Exogenous sucrose increased flavonols,whereas overexpression of the MYB StAN1 induced sucrolytic gene expression.Heterologous StAN1 protein bound promoter fragments from sucrolytic genes(SUSY1 and INV1).Two additional MYBs and one microRNA were identified that regulated potato flavonols.Overexpression analysis showed MYB12A and C increased amounts of flavonols and other phenylpropanoids.Endogenous flavonol amounts in light-exposed organs were much higher those in the dark.Expression levels of StMYB12A and C were high in flowers but low in tubers.Transient overexpression of miR858 altered potato flavonol metabolism.Endogenous StmiR858 expression was much lower in flowers than leaves and correlated with flavonol amounts in these organs.Collectively,these findings support the hypothesis that sucrose,MYBs,and miRNA control potato phenylpropanoid metabolism in a finely tuned manner that includes a feedback loop between sucrose and StAN1.These findings will aid in the development of potatoes with phenylpropanoid profiles optimized for crop performance and human health.展开更多
Ecosystem service values(ESV)are strongly influenced by the vegetation cover,which is heterogeneous across different vegetation types.We develop a dynamic evaluation model of ESV for Wuyishan National Park Pilot adjus...Ecosystem service values(ESV)are strongly influenced by the vegetation cover,which is heterogeneous across different vegetation types.We develop a dynamic evaluation model of ESV for Wuyishan National Park Pilot adjusted by the rate of inflation and the fractional vegetation cover,which is calculated by an enhanced vegetation index from 2000 to 2018.The spatio-temporal variation of vegetation was also examined.The results demonstrated that:(1)the unit area of ecosystem service values adjusted by vegetation cover(ESVVC)shows a gradient of forest>tea plantation>grassland>cropland,and the major ecosystem services provided by forests include soil formation and conservation,climate regulation,and biodiversity maintenance;(2)the ESV_(VC) increased to 2.1 billion yuan(The reference rate announced by the People’s Bank of China is the US dollar to 6.42 Yuan per dollar.)from 2000 to 2018.Higher and lower ESV_(VC) are predominant in the northwest and southeast region,respectively.In addition,changes of ecological protection structures and human disturbances negatively affected vegetation cover,leading to a decreased ESVVC from 2000 to 2005 in the Jiuqu Stream Ecological Protection Area and the Wuyishan National Scenic Spot.The implementation of ecological protection policies from 2010 to 2018 enhanced the ESV_(VC) in the study area;and,(3)the ESVVC is highest in the southeast and 25°–35°area with altitudes of 800–1000 m.Our model can provide timely and helpful information of changes in ESV for use in ecological corridor design and ecological security monitoring.展开更多
Purebred microorganisms were employed to upgrade the fermentation process of Zhejiang rosy vinegar. The fermentation cycle was greatly shorten from 5 months to 72 d. The transformation rate of raw materials was increa...Purebred microorganisms were employed to upgrade the fermentation process of Zhejiang rosy vinegar. The fermentation cycle was greatly shorten from 5 months to 72 d. The transformation rate of raw materials was increased from 1:4.5 in the traditional fermentation to 1:5 or more in the upgraded fermentation. The content of organic acids in the traditional vinegar (TRV), the upgraded vinegar (UPV) and the submerged fermentation vinegar (SFV) were also investigated by HPLC. No significant difference was found regarding the proportion of phenylethanol to the total volatile components in UPV (7.47% ± 0.00324%) and TRV (7.23% ± 0.00329%), but it was significantly higher than that in SFV (2.26% ± 0.00143%). This study provides deep insight into upgrading the fermentation process of Zhejiang rosy vinegar by purebred microorganisms.展开更多
BACKGROUND To summarize the clinical characteristics of acute cerebral infarction(ACI)in patients with sudden deafness(SD)as the first symptom,improve the awareness of the disease,and help diagnosis and treatment.CASE...BACKGROUND To summarize the clinical characteristics of acute cerebral infarction(ACI)in patients with sudden deafness(SD)as the first symptom,improve the awareness of the disease,and help diagnosis and treatment.CASE SUMMARY From 2019 to 2020,three patients with ACI with SD as the first symptom were admitted to our hospital.Pure tone audiometry,head magnetic resonance imaging(MRI),vertebral artery and carotid artery B-ultrasound,head and neck computed tomography angiography,and other examinations were performed.Following the treatment of SD,hearing and dizziness were not significantly improved.Then,the patients developed symptoms of related cranial nerve injury,and brain MRI showed cerebral infarction in the cerebellopontine angle area.All three cases were transferred to the neurology department for relevant conservative treatment.CONCLUSION Patients with ACI with SD as the first symptom usually attend the otolaryngology clinic.Here a diagnosis of SD,which is based on an audiological examination,is made and the corresponding treatment is administered.To reduce the misdiagnosis of this disease,close attention should be paid to the changes in the patient's clinical symptoms and related auxiliary examinations should be performed,such as brain MRI and cerebrovascular imaging.Otolaryngologists should pay attention to the type and severity of hearing loss,the accompanying symptoms,age,high-risk factors for cerebral infarction,and related cranial nerve symptoms in patients with SD.If the patient's early brain MRI does not show abnormalities,monitoring remains essential.The head MRI should be analyzed quickly based on the changes in the symptoms of the patient,to make an accurate diagnosis and provide the timely and correct treatment for the patients.展开更多
CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ce...CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ceria catalysts for NRR remains a challenge due to the poor knowledge of the catalytic mechanism, particularly the nature of the active sites and how they catalyze NRR. Here, using first-principle calculations, we investigated the NRR catalysis process involving adjacent Ce Lewis acid clusters formed on(111),(110), and(100) facets of CeO_(2) as active sites. Our results revealed that the assembled structures of the Ce Lewis acid as active centers after the oxygen vacancies(Ovs) were opened. The exposed Ce sites on CeO_(2)(111), CeO_(2)(110), and CeO_(2)(100) can cause N_(2) to be adsorbed in a ‘‘lying-down" manner, which facilitates the N2 activation and thus leads to much higher NRR activity. Furthermore, from the perspective of electronic structure, we establish two useful descriptors for assessing the NRR activity on ceria with Ovs:The N–N bond strength of the adsorbed N_(2) and the adsorption energy of the *N_(2)H intermediate. This work thus provides direct guidance for the design of more-effective oxide catalysts without the use of scarce metals.展开更多
In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDY...In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDYs increase as the number of halogen atoms increases.It is also found that the position of the valence band maximum(VBM)is influenced by the electronegativity of halogen atoms.The higher the electronegativity,the deeper the VBM of the GDYs modified by the same number of halogen atoms.Importantly,our results revealed that the bandgap of GDY could be effectively tuned by mixing types of halogen atoms.The new generated conduction band and valence band edges are properly aligned with the oxidation and reduction potentials of water.Further thermodynamic analysis confirms that some models with mixing types of halogen atoms exhibit higher performance of overall photocatalytic water splitting than non-mixing models.This work provides useful insights for designing efficient photocatalysts that can be used for overall water splitting.展开更多
We developed a set of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus because of the scientific significance of in-situ Micro-Raman spectroscopy system under the high-pressure hydrothermal...We developed a set of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus because of the scientific significance of in-situ Micro-Raman spectroscopy system under the high-pressure hydrothermal condition.We used this system to measure the Raman spectrum of water-fluid and quartz crystal at the temperature ranging from 125 to 420℃.The signal-tonoise ratio of the Raman signal is good.展开更多
In this work,we explore the suitability of several density functionals with the generalized gradient approximation(GGA)and beyond for describing the dissociative chemisorption of methane on the reconstructed Pt(110)-(...In this work,we explore the suitability of several density functionals with the generalized gradient approximation(GGA)and beyond for describing the dissociative chemisorption of methane on the reconstructed Pt(110)-(2×1)surface.The bulk and surface structures of the metal,methane adsorption energy,and dissociation barrier are used to assess the functionals.A van der Waals corrected GGA functional(optPBE-vdW)and a metaGGA functional with van der Waals correction(MS PBEl-rVV10)are selected for ab initio molecular dynamics calculations of the sticking probability.Our results suggest that the use of these two functionals may lead to a better agreement with existing experimental results,thus serving as a good starting point for future development of reliable machine-learned potential energy surfaces for the dissociation of methane on the Pt(110)-(2×1)surface.展开更多
The development of science and technology is the key to changing human life and promoting social and economic development.As a product of technological development,the widespread application of communication technolog...The development of science and technology is the key to changing human life and promoting social and economic development.As a product of technological development,the widespread application of communication technology has brought a brand new“dawn”to the development of human society.5G wireless communication technology is an advanced wireless communication technology that has recently developed.With the advantages of low energy consumption and high network speed,5G technology has shown very bright development prospects in various fields today.Government,operators and equipment providers are actively promoting and deploying 5G technology,and all links in the industry chain are mature.It is expected that the future market size will reach 17 trillion,especially in today’s industrial field,the application of 5G technology will further enhance work efficiency,ensure work quality,and promote good development in the industrial field.Based on this,this paper will study the development of 5G wireless technology in the industrial field,so as to provide corresponding reference for the good application of 5G technology in the industrial field.展开更多
基金supported by the Science and Technology Foundation of Guizhou Province,China(No.[2020]1Y163)the National Natural Science Foundation of China(No.41827802).
文摘Fe(Ⅲ)has been proved to be a more eff ective oxidant than dissolved oxygen at ambient temperature,however,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so far.In this paper,in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment.The results illustrated that increasing Fe(Ⅲ)concentrations led to raising in redox potential of the solution,and decreased passivation of pyrite caused by deposition of elemental sulfur.Reduction of Fe(Ⅲ)at pyrite surface was a fast reaction with low activation energy,it was only slightly promoted by rising temperatures.While,the oxidation rate of pyrite at all investigated Fe(Ⅲ)concentrations increased obviously with rising temperatures,the anodic reaction was the rate-limiting step in the overall reaction.Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(Ⅲ)concentration was increased from 0.05 to 0.50 g/L,showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(Ⅲ)concentrations,while,it gradually turned to be diffusion control with increasing Fe(Ⅲ)concentrations.
基金financially supported by the Beijing Natural Science Foundation for Young Scientists(Grant No.8214052)the Talent Fund of Beijing Jiaotong University(Grant No.2021RC226)the State Key Laboratory for GeoMechanics and Deep Underground Engineering,China University of Mining and Technology(Grant No.SKLGDUEK2115).
文摘Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natural rock.Extrusion free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature sintering.In this study,we attempted to use the EFF technology to fabricate artificial rock specimens.The results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain impact.The specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural rocks.The density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,respectively.It is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and gneiss.However,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation.
基金supported by National Natural Science Foundation of China(No.51474101,51975202)the equipment pre-research project of China(Nos.41422060204)the Natural Science Foundation of Hunan Province(2019JJ30005).
文摘The effective connection of 1050 Al and AZ31 Mg was realized by magnetic pulse welding.The maximum tensile-shear force of the dissimilar Al/Mg metal lap joint reached 97%of that of the 1050 Al alloy base material by optimizing the process parameters.The microstructure of dissimilar Al/Mg welded joints was analysed by Scanning Electron Microscope(SEM),Energy Dispersive Spectrometer(EDS)and Electron Backscattered Diffraction(EBSD).The results show that the key to obtaining high shear strength of Al/Mg dissimilar metal joints is mainly due to the following two reasons.On the one hand,grain refinement and element interdiffusion occur at the interface.On the other hand,no intermetallic compounds are formed at the interface.
文摘Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water electrolysis.However,highly effective and inexpensive earth-abundant materials are sought after to replace the noble metal-based electrocatalysts currently in use.Recently,metal-organic frameworks(MOFs)and carbon-based MOF derivatives have attracted considerable attention as efficient catalysts due to their exceedingly tunable morphologies,structures,compositions,and functionalization.Here,we report two-dimensional(2D)MOF/MOF derivative coupled arrays on nickel foam as binder-free bifunctional ORR/OER catalysts with enhanced electrocatalytic activity and stability.Their remarkable electrochemical properties are primarily attributed to fully exposed active sites and facilitated charge-transfer kinetics.The coupled and hierarchical nanosheet arrays produced via our growth-pyrolysis-regrowth strategy offer promise in the development of highly active electrodes for energy-related electrochemical devices.
基金the Northwest Potato Research Consortium,and funding from the USDA-Agricultural Research Service 2092-21220-001-00D.
文摘Flavonols and other phenylpropanoids protect plants from biotic and abiotic stress and are dietarily desirable because of their health-promoting properties.The ability to develop new potatoes(Solanum tuberosum)with optimal types and amounts of phenylpropanoids is limited by lack of knowledge about the regulatory mechanisms.Exogenous sucrose increased flavonols,whereas overexpression of the MYB StAN1 induced sucrolytic gene expression.Heterologous StAN1 protein bound promoter fragments from sucrolytic genes(SUSY1 and INV1).Two additional MYBs and one microRNA were identified that regulated potato flavonols.Overexpression analysis showed MYB12A and C increased amounts of flavonols and other phenylpropanoids.Endogenous flavonol amounts in light-exposed organs were much higher those in the dark.Expression levels of StMYB12A and C were high in flowers but low in tubers.Transient overexpression of miR858 altered potato flavonol metabolism.Endogenous StmiR858 expression was much lower in flowers than leaves and correlated with flavonol amounts in these organs.Collectively,these findings support the hypothesis that sucrose,MYBs,and miRNA control potato phenylpropanoid metabolism in a finely tuned manner that includes a feedback loop between sucrose and StAN1.These findings will aid in the development of potatoes with phenylpropanoid profiles optimized for crop performance and human health.
基金This study was supported and funded by the projects of National Natural Science Foundation of China(No.41201100)the projects of Science and Technology Innovation Foundation of FAFU,China(No.KFA18038A).
文摘Ecosystem service values(ESV)are strongly influenced by the vegetation cover,which is heterogeneous across different vegetation types.We develop a dynamic evaluation model of ESV for Wuyishan National Park Pilot adjusted by the rate of inflation and the fractional vegetation cover,which is calculated by an enhanced vegetation index from 2000 to 2018.The spatio-temporal variation of vegetation was also examined.The results demonstrated that:(1)the unit area of ecosystem service values adjusted by vegetation cover(ESVVC)shows a gradient of forest>tea plantation>grassland>cropland,and the major ecosystem services provided by forests include soil formation and conservation,climate regulation,and biodiversity maintenance;(2)the ESV_(VC) increased to 2.1 billion yuan(The reference rate announced by the People’s Bank of China is the US dollar to 6.42 Yuan per dollar.)from 2000 to 2018.Higher and lower ESV_(VC) are predominant in the northwest and southeast region,respectively.In addition,changes of ecological protection structures and human disturbances negatively affected vegetation cover,leading to a decreased ESVVC from 2000 to 2005 in the Jiuqu Stream Ecological Protection Area and the Wuyishan National Scenic Spot.The implementation of ecological protection policies from 2010 to 2018 enhanced the ESV_(VC) in the study area;and,(3)the ESVVC is highest in the southeast and 25°–35°area with altitudes of 800–1000 m.Our model can provide timely and helpful information of changes in ESV for use in ecological corridor design and ecological security monitoring.
文摘Purebred microorganisms were employed to upgrade the fermentation process of Zhejiang rosy vinegar. The fermentation cycle was greatly shorten from 5 months to 72 d. The transformation rate of raw materials was increased from 1:4.5 in the traditional fermentation to 1:5 or more in the upgraded fermentation. The content of organic acids in the traditional vinegar (TRV), the upgraded vinegar (UPV) and the submerged fermentation vinegar (SFV) were also investigated by HPLC. No significant difference was found regarding the proportion of phenylethanol to the total volatile components in UPV (7.47% ± 0.00324%) and TRV (7.23% ± 0.00329%), but it was significantly higher than that in SFV (2.26% ± 0.00143%). This study provides deep insight into upgrading the fermentation process of Zhejiang rosy vinegar by purebred microorganisms.
文摘BACKGROUND To summarize the clinical characteristics of acute cerebral infarction(ACI)in patients with sudden deafness(SD)as the first symptom,improve the awareness of the disease,and help diagnosis and treatment.CASE SUMMARY From 2019 to 2020,three patients with ACI with SD as the first symptom were admitted to our hospital.Pure tone audiometry,head magnetic resonance imaging(MRI),vertebral artery and carotid artery B-ultrasound,head and neck computed tomography angiography,and other examinations were performed.Following the treatment of SD,hearing and dizziness were not significantly improved.Then,the patients developed symptoms of related cranial nerve injury,and brain MRI showed cerebral infarction in the cerebellopontine angle area.All three cases were transferred to the neurology department for relevant conservative treatment.CONCLUSION Patients with ACI with SD as the first symptom usually attend the otolaryngology clinic.Here a diagnosis of SD,which is based on an audiological examination,is made and the corresponding treatment is administered.To reduce the misdiagnosis of this disease,close attention should be paid to the changes in the patient's clinical symptoms and related auxiliary examinations should be performed,such as brain MRI and cerebrovascular imaging.Otolaryngologists should pay attention to the type and severity of hearing loss,the accompanying symptoms,age,high-risk factors for cerebral infarction,and related cranial nerve symptoms in patients with SD.If the patient's early brain MRI does not show abnormalities,monitoring remains essential.The head MRI should be analyzed quickly based on the changes in the symptoms of the patient,to make an accurate diagnosis and provide the timely and correct treatment for the patients.
基金supported by the National Natural Science Foundation of China (21973013 and 21673040 to S.L, and 21962007 to S.Z)the Natural Science Foundation of Fujian Province of China (2020J02025 to S.L)+2 种基金the Natural Science Foundation of Jiangxi Province (2020BABL203009 to S.Z)the Foundation of Jiangxi Educational Committee (GJJ190697 to S.Z)the Qishan Scholarship Program of Fuzhou University (XRC-17055 to S.L)。
文摘CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ceria catalysts for NRR remains a challenge due to the poor knowledge of the catalytic mechanism, particularly the nature of the active sites and how they catalyze NRR. Here, using first-principle calculations, we investigated the NRR catalysis process involving adjacent Ce Lewis acid clusters formed on(111),(110), and(100) facets of CeO_(2) as active sites. Our results revealed that the assembled structures of the Ce Lewis acid as active centers after the oxygen vacancies(Ovs) were opened. The exposed Ce sites on CeO_(2)(111), CeO_(2)(110), and CeO_(2)(100) can cause N_(2) to be adsorbed in a ‘‘lying-down" manner, which facilitates the N2 activation and thus leads to much higher NRR activity. Furthermore, from the perspective of electronic structure, we establish two useful descriptors for assessing the NRR activity on ceria with Ovs:The N–N bond strength of the adsorbed N_(2) and the adsorption energy of the *N_(2)H intermediate. This work thus provides direct guidance for the design of more-effective oxide catalysts without the use of scarce metals.
基金funded by the National Natural Science Foundation of China(No.21973013 and No.21673040)the Natural Science Foundation of Fujian Province of China(No.2020J02025)“Chuying Program”for the Top Young Talents of Fujian Province。
文摘In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDYs increase as the number of halogen atoms increases.It is also found that the position of the valence band maximum(VBM)is influenced by the electronegativity of halogen atoms.The higher the electronegativity,the deeper the VBM of the GDYs modified by the same number of halogen atoms.Importantly,our results revealed that the bandgap of GDY could be effectively tuned by mixing types of halogen atoms.The new generated conduction band and valence band edges are properly aligned with the oxidation and reduction potentials of water.Further thermodynamic analysis confirms that some models with mixing types of halogen atoms exhibit higher performance of overall photocatalytic water splitting than non-mixing models.This work provides useful insights for designing efficient photocatalysts that can be used for overall water splitting.
基金supported by the National Key R&D Program of China(Grant No.2016YFC0600104)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB 18010401)。
文摘We developed a set of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus because of the scientific significance of in-situ Micro-Raman spectroscopy system under the high-pressure hydrothermal condition.We used this system to measure the Raman spectrum of water-fluid and quartz crystal at the temperature ranging from 125 to 420℃.The signal-tonoise ratio of the Raman signal is good.
基金financial support from the National Natural Science Foundation of China(No.21973013 and No.21673040)the National Natural Science Foundation of Fujian Province,China(No.2020J02025)+3 种基金the“Chuying Program”for the Top Young Talents of Fujian Provincesupported financially through a NWO/CW TOP grant(No.715.017.001)by a grant of supercomputer time from NWO Exacte en Natuurwetenschappen(NWO-ENW,No.2019.015)the National Science Foundation(No.CHE1951328)。
文摘In this work,we explore the suitability of several density functionals with the generalized gradient approximation(GGA)and beyond for describing the dissociative chemisorption of methane on the reconstructed Pt(110)-(2×1)surface.The bulk and surface structures of the metal,methane adsorption energy,and dissociation barrier are used to assess the functionals.A van der Waals corrected GGA functional(optPBE-vdW)and a metaGGA functional with van der Waals correction(MS PBEl-rVV10)are selected for ab initio molecular dynamics calculations of the sticking probability.Our results suggest that the use of these two functionals may lead to a better agreement with existing experimental results,thus serving as a good starting point for future development of reliable machine-learned potential energy surfaces for the dissociation of methane on the Pt(110)-(2×1)surface.
文摘The development of science and technology is the key to changing human life and promoting social and economic development.As a product of technological development,the widespread application of communication technology has brought a brand new“dawn”to the development of human society.5G wireless communication technology is an advanced wireless communication technology that has recently developed.With the advantages of low energy consumption and high network speed,5G technology has shown very bright development prospects in various fields today.Government,operators and equipment providers are actively promoting and deploying 5G technology,and all links in the industry chain are mature.It is expected that the future market size will reach 17 trillion,especially in today’s industrial field,the application of 5G technology will further enhance work efficiency,ensure work quality,and promote good development in the industrial field.Based on this,this paper will study the development of 5G wireless technology in the industrial field,so as to provide corresponding reference for the good application of 5G technology in the industrial field.
