Ceramic oxide coatings were prepared on AZ91D magnesium alloys in alkaline silicate solution using micro-arc oxidation(MAO) technique.The corrosion behavior of MAO coating on AZ91D magnesium alloys in NaCl solutions...Ceramic oxide coatings were prepared on AZ91D magnesium alloys in alkaline silicate solution using micro-arc oxidation(MAO) technique.The corrosion behavior of MAO coating on AZ91D magnesium alloys in NaCl solutions with different concentrations(0.1%,0.5%,1.0%,3.5% and 5.0% in mass fraction) was evaluated by electrochemical measurements and immersion tests.The results showed that the corrosion rate of the MAO coated AZ91D increased with increasing chloride ion concentration.The main form of corrosion failure was localized corrosion for the MAO coated AZ91D immersed in higher concentration NaCl solutions(1.0%,3.5% and 5.0%),while it was general corrosion in dilute NaCl solutions(0.1% and 0.5%).Two different stages of the failure process of the MAO coated AZ91D could be identified:1) occurrence of the metastable pits and 2) growth of the pits.Different equivalent circuits were also proposed based on the results of electrochemical impedance spectroscopy(EIS) for the MAO coated AZ91D immersed in different concentrations of NaCl solutions for 120 h.展开更多
Mg-based Mg-TiO2 composite powder was prepared by arc plasma evaporation of the Mg+5%TiO2 mixture followed by passivation in air. ICP, XRD and SEM techniques were used to characterize the composition, phase component...Mg-based Mg-TiO2 composite powder was prepared by arc plasma evaporation of the Mg+5%TiO2 mixture followed by passivation in air. ICP, XRD and SEM techniques were used to characterize the composition, phase components and microstructure of the composite powder. The hydrogen sorption properties of the composite powder were investigated by DSC and PCT techniques. According to the data from PCT measurements, the hydrogenation enthalpy and entropy changes of the composite powder are calculated to be-71.5 kJ/mol and-130.1 J/(K·mol), respectively. Besides, the hydrogenation activation energy is determined to be 77.2 kJ/ mol. The results indicate that TiO2 added into Mg by arc plasma method can act as a catalyst to improve the hydrogen sorption kinetic properties of Mg.展开更多
Al-Si-Fe based alloys are attractive light-weight structural materials for automotive engine components because of their high wear resistance, low density and low thermal expansion. Al-17Si 5Fe-2Cu-lMg-lNi-lZr alloys ...Al-Si-Fe based alloys are attractive light-weight structural materials for automotive engine components because of their high wear resistance, low density and low thermal expansion. Al-17Si 5Fe-2Cu-lMg-lNi-lZr alloys were produced in compact form by a spark plasma sintering (SPS) technique using gas atomized powders. The mean grain size of the compact was 530 nm, and fine equiaxed grains and uniformly distributed precipitates were observed in the compact. The compressive deformation behavior of the SPSed materials was examined at various temperatures and strain rates. All the true stress-true strain curves showed steady state flow after reaching peak stress. The peak stress decreased with increasing test temperature and decreasing strain rate. In the deformed specimens, the equiaxed grain morphology and the dislocation microstructure within the equiaxed grains were observed. These facts strongly indicated the occurrence of dynamic recrystallization during high temperature deformation of the present alloy.展开更多
Although casting is commonly used to process aluminum alloys, powder metallurgy remains a promising technique to develop aluminum based materials for structural and functional applications. The possibility to synthesi...Although casting is commonly used to process aluminum alloys, powder metallurgy remains a promising technique to develop aluminum based materials for structural and functional applications. The possibility to synthesize Al-Mg-Zr alloys through mechanical alloying and spark plasma sintering techniques was explored. Al-10Mg-5Zr and Al-5Mg-1Zr alloyed powders were synthesized through wet ball milling the appropriate amount of elemental powders. The dried milled powders were spark plasma sintered through passing constant pulsed electric current with fixed pulse duration at a pressure of 35 MPa. The samples were vacuum sintered at 450, 500, 550, 600 and 620 ℃ for 10, 15 and 20 min. The Al-10Mg-5Zr alloy displays poor densification at lower sintering temperatures of 450, 500, 550 and 600 ℃. Its sinterability is improved at a temperature of 620 ℃ whereas sintering temperatures higher than 620 ℃ leads to partial melting of the alloy. It is possible to sinter the Al-5Mg-1Zr alloy at 450, 500 and 550 ℃. The increase of sintering temperature improves its densification and increases its hardness. The Al-5Mg-IZr alloy displays better densification and hardness compared to Al-10Mg-5Zr alloys.展开更多
In this paper the self-regeneration process of the mixed resins consisting of cationand anion ion exchangers in the electrolialyser of the packed bed is analyzed and anelectric regeneration method is put forward to su...In this paper the self-regeneration process of the mixed resins consisting of cationand anion ion exchangers in the electrolialyser of the packed bed is analyzed and anelectric regeneration method is put forward to supply the desalinated water by mixedbed The electric regeneration technology is a new one used for regeneration of theexhausted ion exchangers in the mixed bed instead of the traditional regeneratingprocess by using acid and abc liquor Electric energy is consumed to regenerat theion exchangers loaded by salts from water treatment without any chemicals- acid alkali. The advantage of the electric regeneration process edibited convenientoperation, no discharge any waste, and therefore no Polluted to the recehang waterbode and the environmental ground展开更多
Molybdenum disilicide(MoSi_2) based composites with various contents of carbon nanotubes(CNTs) were fabricated by spark plasma sintering(SPS) in vacuum under a pressure of 25 MPa.The composites obtained under a sinter...Molybdenum disilicide(MoSi_2) based composites with various contents of carbon nanotubes(CNTs) were fabricated by spark plasma sintering(SPS) in vacuum under a pressure of 25 MPa.The composites obtained under a sintering temperature of 1500 °C and time of 10 min exhibited optimum mechanical properties at room temperature in terms of fracture toughness and transverse rupture strength.MoSi_2 based composite with 6.0% CNTs(volume fraction) had the highest fracture toughness,transverse rupture strength and hardness,which were improved by about 25.7%,51.5% and 24.4% respectively,as compared with pure MoSi_2.A Mo_(4.8)Si_3C_(0.6) phase was detected in CNTs/MoSi_2 composites by both X-ray diffraction(XRD) method and microstructure analysis with scanning electron microscopy(SEM).It is believed that the fine grains and well dispersed small Mo_(4.8)Si_3C_(0.6) particles had led to a higher hardness and strength of CNTs/MoSi_2 composites because of their particle pullout,crack deflection and micro-bridging effects.展开更多
The paper deals with some questions of important aspects of food safety and application of principles of food physics in the food sector. Food production and processing of quality food and safe food are today of prima...The paper deals with some questions of important aspects of food safety and application of principles of food physics in the food sector. Food production and processing of quality food and safe food are today of primary importance. Food production is based on the principles of Good Agricultural Practice (GAP), Good Manufactoring Practice (GMP) and Good Hygiene Practice (GHP). Recently, the industrial food processing is focused dominantly on the quality, and one of the basic requirements of the quality is the safety. There are different methods and techniques to produce safe food. The up-to-date food technologies and quality measurements (quality control and quality assurance) involve the application of different physical methods, e.g., high pressure, pulsing electrical field, nondestructive techniques, e.g., nuclear magnetic resonance (NMR), near infrared reflectance, near infrared transmittance (NIR-NIT), photo acoustic spectroscopy (PAS) and instrumental neutron activation analysis (INAA) for chemical composition determination, radiation techniques, nanofiltration and reverse osmosis (RO) as well. Using ionizing radiation (nuclear methods) and non-ionizing radiation technologies, it is possible to fulfill a lot of expectations: decrease of microbial contamination, improve of sensory properties, increase of storability, etc..展开更多
Aprotic Li-O2 battery has attracted a great deal of interest because of its high theoretical energy density that is far beyond what the best Li-ion technologies can achieve.However, the present Li-O2 batteries suffer ...Aprotic Li-O2 battery has attracted a great deal of interest because of its high theoretical energy density that is far beyond what the best Li-ion technologies can achieve.However, the present Li-O2 batteries suffer from the low energy efficiency that is limited mainly by the high overpotentials required to re-oxidize Li2O2, the discharge product. Over the past few years, considerable research efforts have been devoted to the understanding of the Li2O2 oxidation reactions. Here, we summarize the results obtained from the fundamental study of the Li2O2 oxidation, including its morphology, reaction route, kinetics, the initial location upon oxidation and the charge transport within Li2O2. A better mechanistic understanding of the Li2O2 oxidation reaction will provide a solid foundation for the realization of practical Li-O2 cells with a higher energy efficiency.展开更多
Activated carbon(AC)in organic electrolytebased electric double-layer capacitors(EDLCs)usually suffers from low specific capacitance.Most studies on AC focus on improving its surface area and optimizing pore structure...Activated carbon(AC)in organic electrolytebased electric double-layer capacitors(EDLCs)usually suffers from low specific capacitance.Most studies on AC focus on improving its surface area and optimizing pore structures to enhance its electrochemical performance in EDLCs.Unfortunately,the interfacial microenvironment,which is composed of nanoporous carbon and the organic electrolyte confined in it,is always ignored.Herein,a simple and powerful strategy to create AC with an ionophobic surface is proposed to address the poor efficiency of the electric doublelayer process.The polar C±F bonds formed in the AC material are characterized through near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopy.The ionophobic characteristic of YP-F60 s in an organic electrolyte is extensively studied via contact angle measurements and smallangle X-ray scattering spectroscopy.An EDLC constructed with YP-F60 s as the electrode and 1 mol L^(-1) tetraethylammonium tetrafluoroborate/propylene carbonate as the electrolyte demonstrates high specific capacitance,low internal resistance,and excellent cycling stability.Our results successfully demonstrate the importance of the interfacial microenvironment of AC and its confined electrolyte to the electrochemical performance of EDLCs.Our work also offers new perspectives on the use of the CF;plasma technique to fabricate low-cost superior carbon for EDLCs.展开更多
Lithium-ion power battery has become one of the main power sources for electric vehicles and hybrid electric vehicles because of superior performance compared with other power sources. In order to ensure the safety an...Lithium-ion power battery has become one of the main power sources for electric vehicles and hybrid electric vehicles because of superior performance compared with other power sources. In order to ensure the safety and improve the performance, the maximum operating temperature and local temperature difference of batteries must be maintained in an appropriate range. The effect of temperature on the capacity fade and aging are simply investigated. The electrode structure, including electrode thickness, particle size and porosity, are analyzed. It is found that all of them have significant influences on the heat generation of battery. Details of various thermal management technologies, namely air based, phase change material based, heat pipe based and liquid based, are discussed and compared from the perspective of improving the external heat dissipation. The selection of different battery thermal management(BTM) technologies should be based on the cooling demand and applications, and liquid cooling is suggested being the most suitable method for large-scale battery pack charged/discharged at higher C-rate and in high-temperature environment. The thermal safety in the respect of propagation and suppression of thermal runaway is analyzed.展开更多
Soft magnetic composite with micro-cellular structure was prepared by spark plasma sintering(SPS) process with Fe73.5Cu1Nb3Si13.5B9 micron-powders clad by 5wt% Zn0.5Ni0.5Fe2O4 nano-particles.The effect of SPS on the m...Soft magnetic composite with micro-cellular structure was prepared by spark plasma sintering(SPS) process with Fe73.5Cu1Nb3Si13.5B9 micron-powders clad by 5wt% Zn0.5Ni0.5Fe2O4 nano-particles.The effect of SPS on the micro structure of the Finemet powder and the micro structure of the composite were studied.It has been found that the as-prepared composite consists of Fe73.5Cu1Nb3Si13.5B9 cells and the cell-wall composed of nano Zn0.5Ni0.5Fe2O4 particles distributing around Fe73.5Cu1Nb3Si13.5B9 cell-body.The composite exhibits low eddy-current loss which is to be resulted by high resistivity of the Zn0.5Ni0.5Fe2O4 cell-wall.The sintered samples were annealed at different temperature and the magnetic properties at different frequency of the annealed samples were measured.It shows that the Zn0.5Ni0.5Fe2O4 cell-wall possesses good thermostability.展开更多
Electrospinning is firstly used to one-pot synthesis of Li3VO4@C nanofibers in a large scale. Although with the presence of organic sources in synthesis process, the pure phase Li3VO4 with superior nanofibrous morphol...Electrospinning is firstly used to one-pot synthesis of Li3VO4@C nanofibers in a large scale. Although with the presence of organic sources in synthesis process, the pure phase Li3VO4 with superior nanofibrous morphology is still successfully obtained through adjusting different heat treatment processes and different vanadium sources. The prepared Li3VO4@C nanofibers exhibit a unique structure in which nanosized Li3VO4 particles are uniformly embedded in amorphous carbon matrix. Compared with LiBVO4/C powder, Li3VO4@C nanofibers display enhanced reversible capacity of 451 mAhg^-1 at 40mAg^-1 with an increased initial coulombic efficiency of 82.3%, and the capacity can remain at 394 mAh g ^-1 after 100 cycles. This superior electrochemical performance can be attributed to its unique structure which ensures a high reactivity by nanosized Li3VO4, more stable electrode/electrolyte interface by carbon encapsulation, improved electronic conductivity and buffered volume changes by flexible carbon matrix. The electrospinning technology provides an effective method to obtain high performance Li3VO4 as a promising anode material for lithium-ion batteries.展开更多
The synthesis of high quality all-inorganic perovskite nanowires needs the harsh conditions,complex process and precision instruments,which are not beneficial to their extensive application.Here,all-inorganic perovski...The synthesis of high quality all-inorganic perovskite nanowires needs the harsh conditions,complex process and precision instruments,which are not beneficial to their extensive application.Here,all-inorganic perovskite ce- sium lead bromine (CsPbBr3)nanowires (NWs)are demonstrated with the combination of solution-phase process and halide exchange technology.A metal-semiconductor-metal structure CsPbBr3 nanowire photodetector was prepared, which showed a detectivity as high as 1.7×10^11 cm Hz^1/2W^-1 (Jones)with rapid response time (The rise and decay time are 10ms and 22 ms,respectively).Moreover,our photodetectors have high stability under ultraviolet (UV)light,high temperature and humidity.展开更多
The capacity of supercapacitor charge storage depends on the size of the electrode surface area and the active material on the electrodes.To enhance the charge storage capacity with a reduced volume,silicon is used as...The capacity of supercapacitor charge storage depends on the size of the electrode surface area and the active material on the electrodes.To enhance the charge storage capacity with a reduced volume,silicon is used as the electrode material,and three-dimensional electrode structure is prepared to increase the electrode surface area on the footprint area by inductively coupled plasma reactive etching(ICP) techniques.The anodic constant current deposition method is employed to deposit manganese oxide on the electrode surface as the electroactive material.For comparison,samples without slot are prepared with a two-dimensional electrode.Scanning Electron Microscopy(SEM) and Energy Dispersive Spectroscopy(EDS) are used to characterize the surface morphology of the electrode structure and the deposited electroactive material.Electrochemical properties of the electrode are characterized by the cyclic voltammetry(CV) and the constant current charge-discharge method.Experimental results show that our approach can effectively increase the electrode surface area with more electroactive substances,and hence can increase storage capacity of the micro-supercapacitor.展开更多
The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending spec...The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending specimen that can generate a single interface crack to facilitate the control of crack growth was adopted for testing, which was conducted at the ambient temperature of 100 °C. The morphology and composition of fractured surfaces were examined by means of a scanning electron microscopy (SEM) and an energy disperse spectroscopy (EDS). Images and spectrum show that cracks are initiated and propagated exclusively within YSZ layer adjacent to top/bond coat interface. The load-displacement curves obtained exhibit similar shapes that indicate two distinct stages in crack initiation and stable crack growth. Finite element analyses were performed to extract the adhesion strength of the TBCs. The delamination toughness of the plasma-sprayed 8YSZ coatings at 100 °C, in terms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution.展开更多
Room-temperature sodium-ion batteries have attracted increasing interest in recent years because of abundant sodium reserves and the low costs.Grid-scale energy storage applications are particularly relevant to this b...Room-temperature sodium-ion batteries have attracted increasing interest in recent years because of abundant sodium reserves and the low costs.Grid-scale energy storage applications are particularly relevant to this battery technology.Here,we present our recent progress in researching room-temperature sodium-ion batteries,and focus on new electrode materials,including cathodes and anodes,for both non-aqueous and aqueous systems.展开更多
Technetium-99(~99Tc),largely produced by nuclear fission of ~235U or ~239Pu,is a component of radioactive waste.This study focused on a remediation strategy for the reduction of pertechnetate(Tc O_4^-)by studying its ...Technetium-99(~99Tc),largely produced by nuclear fission of ~235U or ~239Pu,is a component of radioactive waste.This study focused on a remediation strategy for the reduction of pertechnetate(Tc O_4^-)by studying its chemical analogue rhenium(Re(VⅡ))to avoid the complication of directly working with radioactive elements.Nanoscale zero-valent iron particles supported on graphene(NZVI/r GOs)from GOs-bound Fe ions were prepared by using a H_2/Ar plasma technique and were applied in the reductive immobilization of perrhenate(Re O_4^-).The experimental results demonstrated that NZVI/r GOs could efficiently remove Re from the aqueous solution,with enhanced reactivity,improved kinetics(50 min to reach equilibrium)and excellent removal capacity(85.77 mg/g).The results of X-ray photoelectron spectroscopy analysis showed that the mechanisms of Re immobilization by NZVI/r GOs included adsorption and reduction,which are significant to the prediction and estimation of the effectiveness of reductive Tc O_4^- by NZVI/r GOs in the natural environment.展开更多
基金Project (2007CB613700) supported by the National Basic Research Program of ChinaProject supported by Research Program of Excellent Scholars Studying Abroad of Ministry of Human Resources and Social Security,China
文摘Ceramic oxide coatings were prepared on AZ91D magnesium alloys in alkaline silicate solution using micro-arc oxidation(MAO) technique.The corrosion behavior of MAO coating on AZ91D magnesium alloys in NaCl solutions with different concentrations(0.1%,0.5%,1.0%,3.5% and 5.0% in mass fraction) was evaluated by electrochemical measurements and immersion tests.The results showed that the corrosion rate of the MAO coated AZ91D increased with increasing chloride ion concentration.The main form of corrosion failure was localized corrosion for the MAO coated AZ91D immersed in higher concentration NaCl solutions(1.0%,3.5% and 5.0%),while it was general corrosion in dilute NaCl solutions(0.1% and 0.5%).Two different stages of the failure process of the MAO coated AZ91D could be identified:1) occurrence of the metastable pits and 2) growth of the pits.Different equivalent circuits were also proposed based on the results of electrochemical impedance spectroscopy(EIS) for the MAO coated AZ91D immersed in different concentrations of NaCl solutions for 120 h.
基金Project(11ZR1417600)supported by Shanghai Natural Science Foundation from Science and Technology Committee of Shanghai,ChinaProject(11PJ1406000)supported by‘Pujiang’Project from the Science and Technology Committee of Shanghai+1 种基金Project(12ZZ017)supported by Shanghai Education Commission,ChinaProject(20100073120007)supported by China Education Commission
文摘Mg-based Mg-TiO2 composite powder was prepared by arc plasma evaporation of the Mg+5%TiO2 mixture followed by passivation in air. ICP, XRD and SEM techniques were used to characterize the composition, phase components and microstructure of the composite powder. The hydrogen sorption properties of the composite powder were investigated by DSC and PCT techniques. According to the data from PCT measurements, the hydrogenation enthalpy and entropy changes of the composite powder are calculated to be-71.5 kJ/mol and-130.1 J/(K·mol), respectively. Besides, the hydrogenation activation energy is determined to be 77.2 kJ/ mol. The results indicate that TiO2 added into Mg by arc plasma method can act as a catalyst to improve the hydrogen sorption kinetic properties of Mg.
基金the financial supports of the Ministry of Knowledge Economy (Republic of Korea) through Grant No. 10033429Inha University Research Grant
文摘Al-Si-Fe based alloys are attractive light-weight structural materials for automotive engine components because of their high wear resistance, low density and low thermal expansion. Al-17Si 5Fe-2Cu-lMg-lNi-lZr alloys were produced in compact form by a spark plasma sintering (SPS) technique using gas atomized powders. The mean grain size of the compact was 530 nm, and fine equiaxed grains and uniformly distributed precipitates were observed in the compact. The compressive deformation behavior of the SPSed materials was examined at various temperatures and strain rates. All the true stress-true strain curves showed steady state flow after reaching peak stress. The peak stress decreased with increasing test temperature and decreasing strain rate. In the deformed specimens, the equiaxed grain morphology and the dislocation microstructure within the equiaxed grains were observed. These facts strongly indicated the occurrence of dynamic recrystallization during high temperature deformation of the present alloy.
基金Project(ARP-28-122) supported by King Abdul Aziz City for Science and Technology (KAC ST) of Kingdom of Saudi Arabia
文摘Although casting is commonly used to process aluminum alloys, powder metallurgy remains a promising technique to develop aluminum based materials for structural and functional applications. The possibility to synthesize Al-Mg-Zr alloys through mechanical alloying and spark plasma sintering techniques was explored. Al-10Mg-5Zr and Al-5Mg-1Zr alloyed powders were synthesized through wet ball milling the appropriate amount of elemental powders. The dried milled powders were spark plasma sintered through passing constant pulsed electric current with fixed pulse duration at a pressure of 35 MPa. The samples were vacuum sintered at 450, 500, 550, 600 and 620 ℃ for 10, 15 and 20 min. The Al-10Mg-5Zr alloy displays poor densification at lower sintering temperatures of 450, 500, 550 and 600 ℃. Its sinterability is improved at a temperature of 620 ℃ whereas sintering temperatures higher than 620 ℃ leads to partial melting of the alloy. It is possible to sinter the Al-5Mg-1Zr alloy at 450, 500 and 550 ℃. The increase of sintering temperature improves its densification and increases its hardness. The Al-5Mg-IZr alloy displays better densification and hardness compared to Al-10Mg-5Zr alloys.
文摘In this paper the self-regeneration process of the mixed resins consisting of cationand anion ion exchangers in the electrolialyser of the packed bed is analyzed and anelectric regeneration method is put forward to supply the desalinated water by mixedbed The electric regeneration technology is a new one used for regeneration of theexhausted ion exchangers in the mixed bed instead of the traditional regeneratingprocess by using acid and abc liquor Electric energy is consumed to regenerat theion exchangers loaded by salts from water treatment without any chemicals- acid alkali. The advantage of the electric regeneration process edibited convenientoperation, no discharge any waste, and therefore no Polluted to the recehang waterbode and the environmental ground
基金Project(51371155)supported by the National Natural Science Foundation of ChinaProject(2014H0046)supported by the Key Science and Technology Project of Fujian Province,China+2 种基金Project(3502Z20143036)supported by the Scientific Research Fund of Xiamen,ChinaProject(JB13149)supported by the Education Department Science and Technology Project of Fujian Province,ChinaProject(2012D131)supported by the Natural Science Foundation Guidance Project of Fujian Province,China
文摘Molybdenum disilicide(MoSi_2) based composites with various contents of carbon nanotubes(CNTs) were fabricated by spark plasma sintering(SPS) in vacuum under a pressure of 25 MPa.The composites obtained under a sintering temperature of 1500 °C and time of 10 min exhibited optimum mechanical properties at room temperature in terms of fracture toughness and transverse rupture strength.MoSi_2 based composite with 6.0% CNTs(volume fraction) had the highest fracture toughness,transverse rupture strength and hardness,which were improved by about 25.7%,51.5% and 24.4% respectively,as compared with pure MoSi_2.A Mo_(4.8)Si_3C_(0.6) phase was detected in CNTs/MoSi_2 composites by both X-ray diffraction(XRD) method and microstructure analysis with scanning electron microscopy(SEM).It is believed that the fine grains and well dispersed small Mo_(4.8)Si_3C_(0.6) particles had led to a higher hardness and strength of CNTs/MoSi_2 composites because of their particle pullout,crack deflection and micro-bridging effects.
文摘The paper deals with some questions of important aspects of food safety and application of principles of food physics in the food sector. Food production and processing of quality food and safe food are today of primary importance. Food production is based on the principles of Good Agricultural Practice (GAP), Good Manufactoring Practice (GMP) and Good Hygiene Practice (GHP). Recently, the industrial food processing is focused dominantly on the quality, and one of the basic requirements of the quality is the safety. There are different methods and techniques to produce safe food. The up-to-date food technologies and quality measurements (quality control and quality assurance) involve the application of different physical methods, e.g., high pressure, pulsing electrical field, nondestructive techniques, e.g., nuclear magnetic resonance (NMR), near infrared reflectance, near infrared transmittance (NIR-NIT), photo acoustic spectroscopy (PAS) and instrumental neutron activation analysis (INAA) for chemical composition determination, radiation techniques, nanofiltration and reverse osmosis (RO) as well. Using ionizing radiation (nuclear methods) and non-ionizing radiation technologies, it is possible to fulfill a lot of expectations: decrease of microbial contamination, improve of sensory properties, increase of storability, etc..
基金supported by the Recruitment Program of Global Youth Experts of Chinathe Strategic Priority Research Program of the Chinese Academy of Sciences(XDA09010401)the Science and Technology Development Program of the Jilin Province(20150623002TC)
文摘Aprotic Li-O2 battery has attracted a great deal of interest because of its high theoretical energy density that is far beyond what the best Li-ion technologies can achieve.However, the present Li-O2 batteries suffer from the low energy efficiency that is limited mainly by the high overpotentials required to re-oxidize Li2O2, the discharge product. Over the past few years, considerable research efforts have been devoted to the understanding of the Li2O2 oxidation reactions. Here, we summarize the results obtained from the fundamental study of the Li2O2 oxidation, including its morphology, reaction route, kinetics, the initial location upon oxidation and the charge transport within Li2O2. A better mechanistic understanding of the Li2O2 oxidation reaction will provide a solid foundation for the realization of practical Li-O2 cells with a higher energy efficiency.
基金supported by the National Natural Science Foundation of China(21203008 and 21975025)Beijing Natural Science Foundation(2172051)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University。
文摘Activated carbon(AC)in organic electrolytebased electric double-layer capacitors(EDLCs)usually suffers from low specific capacitance.Most studies on AC focus on improving its surface area and optimizing pore structures to enhance its electrochemical performance in EDLCs.Unfortunately,the interfacial microenvironment,which is composed of nanoporous carbon and the organic electrolyte confined in it,is always ignored.Herein,a simple and powerful strategy to create AC with an ionophobic surface is proposed to address the poor efficiency of the electric doublelayer process.The polar C±F bonds formed in the AC material are characterized through near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopy.The ionophobic characteristic of YP-F60 s in an organic electrolyte is extensively studied via contact angle measurements and smallangle X-ray scattering spectroscopy.An EDLC constructed with YP-F60 s as the electrode and 1 mol L^(-1) tetraethylammonium tetrafluoroborate/propylene carbonate as the electrolyte demonstrates high specific capacitance,low internal resistance,and excellent cycling stability.Our results successfully demonstrate the importance of the interfacial microenvironment of AC and its confined electrolyte to the electrochemical performance of EDLCs.Our work also offers new perspectives on the use of the CF;plasma technique to fabricate low-cost superior carbon for EDLCs.
基金Supported by National Natural Science Foundation of China(No.51376019)
文摘Lithium-ion power battery has become one of the main power sources for electric vehicles and hybrid electric vehicles because of superior performance compared with other power sources. In order to ensure the safety and improve the performance, the maximum operating temperature and local temperature difference of batteries must be maintained in an appropriate range. The effect of temperature on the capacity fade and aging are simply investigated. The electrode structure, including electrode thickness, particle size and porosity, are analyzed. It is found that all of them have significant influences on the heat generation of battery. Details of various thermal management technologies, namely air based, phase change material based, heat pipe based and liquid based, are discussed and compared from the perspective of improving the external heat dissipation. The selection of different battery thermal management(BTM) technologies should be based on the cooling demand and applications, and liquid cooling is suggested being the most suitable method for large-scale battery pack charged/discharged at higher C-rate and in high-temperature environment. The thermal safety in the respect of propagation and suppression of thermal runaway is analyzed.
基金supported by the National Natural Science Foundations of China (Grant Nos. 50771023 and 51071034)
文摘Soft magnetic composite with micro-cellular structure was prepared by spark plasma sintering(SPS) process with Fe73.5Cu1Nb3Si13.5B9 micron-powders clad by 5wt% Zn0.5Ni0.5Fe2O4 nano-particles.The effect of SPS on the micro structure of the Finemet powder and the micro structure of the composite were studied.It has been found that the as-prepared composite consists of Fe73.5Cu1Nb3Si13.5B9 cells and the cell-wall composed of nano Zn0.5Ni0.5Fe2O4 particles distributing around Fe73.5Cu1Nb3Si13.5B9 cell-body.The composite exhibits low eddy-current loss which is to be resulted by high resistivity of the Zn0.5Ni0.5Fe2O4 cell-wall.The sintered samples were annealed at different temperature and the magnetic properties at different frequency of the annealed samples were measured.It shows that the Zn0.5Ni0.5Fe2O4 cell-wall possesses good thermostability.
基金supported by the National Natural Science Foundation of China (21571073, 51302099, 51472097)the Ministry of Science and Technology of China (2015CB932600)+2 种基金the Hubei Provincial Natural Science Foundation (2016CFA031)the Program for Huazhong University of Science and Technology (HUST) Interdisciplinary Innovation Team (2015ZDTD038)the Fundamental Research Funds for the Central University (2017KFKJXX007)
文摘Electrospinning is firstly used to one-pot synthesis of Li3VO4@C nanofibers in a large scale. Although with the presence of organic sources in synthesis process, the pure phase Li3VO4 with superior nanofibrous morphology is still successfully obtained through adjusting different heat treatment processes and different vanadium sources. The prepared Li3VO4@C nanofibers exhibit a unique structure in which nanosized Li3VO4 particles are uniformly embedded in amorphous carbon matrix. Compared with LiBVO4/C powder, Li3VO4@C nanofibers display enhanced reversible capacity of 451 mAhg^-1 at 40mAg^-1 with an increased initial coulombic efficiency of 82.3%, and the capacity can remain at 394 mAh g ^-1 after 100 cycles. This superior electrochemical performance can be attributed to its unique structure which ensures a high reactivity by nanosized Li3VO4, more stable electrode/electrolyte interface by carbon encapsulation, improved electronic conductivity and buffered volume changes by flexible carbon matrix. The electrospinning technology provides an effective method to obtain high performance Li3VO4 as a promising anode material for lithium-ion batteries.
基金supported by the National Natural Science Foundation of China (51372075)
文摘The synthesis of high quality all-inorganic perovskite nanowires needs the harsh conditions,complex process and precision instruments,which are not beneficial to their extensive application.Here,all-inorganic perovskite ce- sium lead bromine (CsPbBr3)nanowires (NWs)are demonstrated with the combination of solution-phase process and halide exchange technology.A metal-semiconductor-metal structure CsPbBr3 nanowire photodetector was prepared, which showed a detectivity as high as 1.7×10^11 cm Hz^1/2W^-1 (Jones)with rapid response time (The rise and decay time are 10ms and 22 ms,respectively).Moreover,our photodetectors have high stability under ultraviolet (UV)light,high temperature and humidity.
文摘The capacity of supercapacitor charge storage depends on the size of the electrode surface area and the active material on the electrodes.To enhance the charge storage capacity with a reduced volume,silicon is used as the electrode material,and three-dimensional electrode structure is prepared to increase the electrode surface area on the footprint area by inductively coupled plasma reactive etching(ICP) techniques.The anodic constant current deposition method is employed to deposit manganese oxide on the electrode surface as the electroactive material.For comparison,samples without slot are prepared with a two-dimensional electrode.Scanning Electron Microscopy(SEM) and Energy Dispersive Spectroscopy(EDS) are used to characterize the surface morphology of the electrode structure and the deposited electroactive material.Electrochemical properties of the electrode are characterized by the cyclic voltammetry(CV) and the constant current charge-discharge method.Experimental results show that our approach can effectively increase the electrode surface area with more electroactive substances,and hence can increase storage capacity of the micro-supercapacitor.
基金Project (No 2007CB707702) supported by the National Basic Research Program (973) of China
文摘The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending specimen that can generate a single interface crack to facilitate the control of crack growth was adopted for testing, which was conducted at the ambient temperature of 100 °C. The morphology and composition of fractured surfaces were examined by means of a scanning electron microscopy (SEM) and an energy disperse spectroscopy (EDS). Images and spectrum show that cracks are initiated and propagated exclusively within YSZ layer adjacent to top/bond coat interface. The load-displacement curves obtained exhibit similar shapes that indicate two distinct stages in crack initiation and stable crack growth. Finite element analyses were performed to extract the adhesion strength of the TBCs. The delamination toughness of the plasma-sprayed 8YSZ coatings at 100 °C, in terms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution.
基金supported by funding from the National Natural Science Foundation of China(51222210,50972164,11234013,11005161,11205249)One Hundred Talent Project of the Chinese Academy of Sciences
文摘Room-temperature sodium-ion batteries have attracted increasing interest in recent years because of abundant sodium reserves and the low costs.Grid-scale energy storage applications are particularly relevant to this battery technology.Here,we present our recent progress in researching room-temperature sodium-ion batteries,and focus on new electrode materials,including cathodes and anodes,for both non-aqueous and aqueous systems.
基金the National Natural Science Foundation of China(21477133,41273134,91326202,21225730)
文摘Technetium-99(~99Tc),largely produced by nuclear fission of ~235U or ~239Pu,is a component of radioactive waste.This study focused on a remediation strategy for the reduction of pertechnetate(Tc O_4^-)by studying its chemical analogue rhenium(Re(VⅡ))to avoid the complication of directly working with radioactive elements.Nanoscale zero-valent iron particles supported on graphene(NZVI/r GOs)from GOs-bound Fe ions were prepared by using a H_2/Ar plasma technique and were applied in the reductive immobilization of perrhenate(Re O_4^-).The experimental results demonstrated that NZVI/r GOs could efficiently remove Re from the aqueous solution,with enhanced reactivity,improved kinetics(50 min to reach equilibrium)and excellent removal capacity(85.77 mg/g).The results of X-ray photoelectron spectroscopy analysis showed that the mechanisms of Re immobilization by NZVI/r GOs included adsorption and reduction,which are significant to the prediction and estimation of the effectiveness of reductive Tc O_4^- by NZVI/r GOs in the natural environment.