Separator modification is an effective approach to suppress dendrite growth to realize high-energy sodium metal batteries(SMBs)in practical applications,however,its success is mainly subject to surface modification.He...Separator modification is an effective approach to suppress dendrite growth to realize high-energy sodium metal batteries(SMBs)in practical applications,however,its success is mainly subject to surface modification.Herein,a separator with multifunctional layers composed of N-doped mesoporous hollow carbon spheres(HCS)as the inner layer and sodium fluoride(NaF)as the outer layer on commercial polypropylene separator(PP)is proposed(PP@HCS-NaF)to achieve stable cycling in SMB.At the molecular level,the inner HCS layer with a high content of pyrrolic-N induces the uniform Na^(+)flux as a potential Na^(+)redistributor for homogenous deposition,whereas its hollow mesoporous structure offers nanoporous buffers and ion channels to regulate Na^(+)ion distribution and uniform deposition.The outer layer(NaF)constructs the NaF-enriched robust solid electrolyte interphase layer,significantly lowering the Na^(+)ions diffusion barrier.Benefiting from these merits,higher electrochemical performances are achieved with multifunctional double-layered PP@HCS-NaF separators compared with single-layered separators(i.e.PP@HCS or PP@NaF)in SMBs.The Na‖Cu half-cell with PP@HCS-NaF offers stable cycling(280 cycles)with a high CE(99.6%),and Na‖Na symmetric cells demonstrate extended lifespans for over 6000 h at 1 mA cm^(-2)with a progressively stable overpotential of 9 mV.Remarkably,in Na‖NVP full-cells,the PP@HCS-NaF separator grants a stable capacity of~81 mA h g^(-1)after 3500 cycles at 1 C and an impressive rate capability performance(~70 mA h g^(-1)at 15 C).展开更多
Searching for compatible electrolytes with Ni_(0.8)C_(00.15)Al_(0.05)LiO_(2-δ)(NCAL)electrodes that exhibit high ionic conductivity at low operational temperatures(<550℃)is crucial for advancing ceramics fuel cel...Searching for compatible electrolytes with Ni_(0.8)C_(00.15)Al_(0.05)LiO_(2-δ)(NCAL)electrodes that exhibit high ionic conductivity at low operational temperatures(<550℃)is crucial for advancing ceramics fuel cells(CFCs)research.In this work,the experimental and theoretical analyses demonstrate that the highly stable single-phase Gd_(3)Ga_(5)O_(12)(GGO)garnet structure,composed of Gd-O octahedrons and Ga-O tetrahedrons,provides more active sites for ion transport,resulting in enhanced peak power density(PPD)and stable open circuit voltage(OCV)at low operational temperatures.The unique internal garnet structure effectively reduces the interfacial impedance of the prepared fuel cell device,provides more active sites at triple-phase boundarie region,and increases the electrochemical stability.As a result,the constructed fuel cell device can deliver a superior peak power density of 770 mW/cm^(2)at 490℃.In addition,X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,and theoretical calculations further demonstrate electrolyte effectiveness of GGO,enabling stable an OCV even at a low temperature of 370℃under a H_(2)/air environment.This work contributes to a deeper understanding of the underlying mechanisms of a single-layer fuel cell device,which is essential for advancing this promising energy technology,even at a very low temperature of 370℃.展开更多
Enhancing the electrocatalytic activity of the electrode materials,specifically oxygen reduction reaction(ORR),at lower operating temperatures(<600℃)is the prime rank to realize the commercialization of solid oxid...Enhancing the electrocatalytic activity of the electrode materials,specifically oxygen reduction reaction(ORR),at lower operating temperatures(<600℃)is the prime rank to realize the commercialization of solid oxide fuel cells(SOFCs)research.Herein,a new hexagonal structure-based cathode material was developed with the co-doping of Gd_(2)O_(3)and Cr_(2)O_(3)of parent SrFe_(12)O_(19)oxide,respectively.At 550-475℃,Sr_(0.90)Gd_(0.10)Fe_(11.90)Cr_(0.10)O_(19)(SFO-10)cathode sample leading to the large peak power density(PPD)of 395 mW/cm^(2),has appropriate surface oxygen defects(O_(β))up to 17%,as verified by X-ray photoelectron microscopy(XPS).Theoretical calculations reveal that the co-doping of Gd and Cr oxides creates lattice disorder at the hexagonal lattice,which decreases the energy barrier for ion transport and enhances the electrocatalytic characteristics of ORR.Consequently,the SFO-10 cathode shows a favorable ORR activity with the least lower polarization resistance(ASR)at 550℃with gadolinium-doped ceria(GDC)electrolyte.This work provides a self-assembled single-phase hexagonal cathode to accelerate the lowtemperature hindrance of SOFC technology.展开更多
Rare earth(RE)low doping has a significant influence on the structural,morphological,and magnetic properties of spinel ferrite nanoparticles.Therefore,rare earth neodymium(Nd)oxide was fully doped into spinel ferrite ...Rare earth(RE)low doping has a significant influence on the structural,morphological,and magnetic properties of spinel ferrite nanoparticles.Therefore,rare earth neodymium(Nd)oxide was fully doped into spinel ferrite with a composition of Co_(0.80)Ni_(0.20)Nd_xFe_(2-x)O_4(x=0.0,0.05,0.10,and 0.15)using the sol-gel auto combustion method.Structural analysis of the synthesized samples with low doping of Nd using X-ray diffraction(XRD)and Rietveld refinements reveals a pure single-phase cubic structure,while the second phase appears with increasing content of Nd^(3+)at x=0.10 and 0.15.Scanning electron microscopy(SEM)and high-resolution transmission electron microscopy(HR-TEM)show well-shaped spherical grains within the nanometer range of the pure Co_(0.80)Ni_(0.20)Fe_(2)O_(4) sample,while larger grains with the presence of agglomeration are observed with doping of Nd^(3+)into the spinel ferrite nanoparticles.The magnetic parameters,i.e.,saturation magnetization M_s,remanence and magnetic moments exhibit decreasing trend with Nd^(3+)doping and M_s values are in 65.69 to 53.34 emu/g range.The coercivity of the Nd-doped Co-Ni spinel ferrite sample was calculated to be 1037.76 to~827.24 Oe.This work demonstrates remarkable improvements in the structural and magnetic characteristics of Nddoped Co-Ni spinel ferrite nanoparticles for multiple versatile applications.展开更多
Rare earths(REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications.In the present study,the nanoferrites of CuRE0.02...Rare earths(REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications.In the present study,the nanoferrites of CuRE0.02Fe1.98O4,where REs=Y^(3+),Yb^(3+),Gd^(3+),were prepared using one step sol-gel method.The prepared samples are copper ferrite(CFO),yttrium doped copper ferrite(Y-CFO),ytterbium doped copper ferrite(Yb-CFO) and gadolinium doped copper ferrite(Gd-CFO),respectively.The single-phase structure of all the REs doped nanoferrites was determined by X-ray diffraction(XRD) analysis.The porosity,agglomerations and grain size of the REs doped copper ferrite were examined using field emission scanning electron microscopy(FESEM) analysis.Fourier transform infrared spectroscopy(FTIR)elaborates the phase formation and environmental effects on the REs doped nanoparticles(NPs).The recorded room temperature M-H loops from a vibrating sample magnetometer(VSM) elucidate the magnetic properties of the REs doped spinel nanoferrites.The magnetic saturation(Ms) was calculated in the range of 23.08 to 51.78 emu/g.The calculated coercivity values(272.6 to 705.60 Oe) confirm the soft magnetic behavior of REs doped copper ferrites.Furthermore,the electromagnetic and dielectric properties were assessed using a Vector network analyzer(VNA) from 1 to 6 GHz.The permeability,permittivity,dielectric tangent loss and electric modulus of the REs doped spinel ferrites illustrate that the prepared NPs may be suitable for microwave and high frequency applications.展开更多
Quantitative security metrics are desirable for measuring the performance of information security controls. Security metrics help to make functional and business decisions for improving the performance and cost of the...Quantitative security metrics are desirable for measuring the performance of information security controls. Security metrics help to make functional and business decisions for improving the performance and cost of the security controls. However, defining enterprise-level security metrics has already been listed as one of the hard problems in the Info Sec Research Council's hard problems list. Almost all the efforts in defining absolute security metrics for the enterprise security have not been proved fruitful. At the same time, with the maturity of the security industry, there has been a continuous emphasis from the regulatory bodies on establishing measurable security metrics. This paper addresses this need and proposes a relative security metric model that derives three quantitative security metrics named Attack Resiliency Measure(ARM), Performance Improvement Factor(PIF), and Cost/Benefit Measure(CBM) for measuring the performance of the security controls. For the effectiveness evaluation of the proposed security metrics, we took the secure virtual machine(VM) migration protocol as the target of assessment. The virtual-ization technologies are rapidly changing the landscape of the computing world. Devising security metrics for virtualized environment is even more challenging. As secure virtual machine migration is an evolving area and no standard protocol is available specifically for secure VM migration. This paper took the secure virtual machine migration protocol as the target of assessment and applied the proposed relative security metric model for measuring the Attack Resiliency Measure, Performance Improvement Factor, and Cost/Benefit Measure of the secure VM migration protocol.展开更多
With an ever increasing energy demand and environmental issues,many state-of-the-art nanostructured electrode materials have been developed for energy storage devices and they include batteries,supercapacitors and fue...With an ever increasing energy demand and environmental issues,many state-of-the-art nanostructured electrode materials have been developed for energy storage devices and they include batteries,supercapacitors and fuel cells.Among these electrode materials,L-TMD(layered transition metal dichalcogenide)nanosheets(especially,S(sulfur)and Se(selenium)based dichaleogenides)have received a lot of attention due to their intriguing layered structure for enhanced electrochemical properties.L-TMD composites have recently been investigated not only as a main charge storage specie but also,as a substrate to hold the active specie.This review highlights the recent advancements in L-TMD composites with 0D(0-dimensional),1 D,2D,3D and various forms of carbon structures and their potential applications in LIB(lithium ion battery)and SIB(sodium ion battery).展开更多
Rationale:SARS-CoV-2 has been identified as a highly infective and contagious viral infection.The SARS-CoV-2 pandemic has been spread worldwide and affected more than 210 countries.Globally,the fast spread of novel SA...Rationale:SARS-CoV-2 has been identified as a highly infective and contagious viral infection.The SARS-CoV-2 pandemic has been spread worldwide and affected more than 210 countries.Globally,the fast spread of novel SARS-CoV-2 variants has been mostly attributed to international travel.Patient concerns:We are reporting the genomic evidence of SARSCoV-2 Eta VOI among two international travelers.Both travelers were males from Nigeria aged 24 and 34 years and both were asymptomatic.Diagnosis:The nasopharyngeal swab samples were in both travelers positive by real-time RT-PCR followed by COVIDSeq-NGS.Interventions:Paracetamol 3 times daily for 5 days.Outcomes:Patient recovered completely within 10 days and discharged after 14 days of quarantine duration.Lessons:This report highlights genomic variation of SARSCoV-2 among the travelers.For managing the present health crisis,molecular identification of viral variants present in different geographical locations will be very helpful.展开更多
The dynamics of inviscid multi-component relativistic fluids may be modeled by the relativistic Euler equations, augmented by one (or more) additional species equation(s). We use the high-resolution staggered central ...The dynamics of inviscid multi-component relativistic fluids may be modeled by the relativistic Euler equations, augmented by one (or more) additional species equation(s). We use the high-resolution staggered central schemes to solve these equations. The equilibrium states for each component are coupled in space and time to have a common temperature and velocity. The current schemes can handle strong shocks and the oscillations near the interfaces are negligible, which usually happens in the multi-component flows. The schemes also guarantee the exact mass conservation for each component, the exact conservation of total momentum, and energy in the whole particle system. The central schemes are robust, reliable, compact and easy to implement. Several one- and two-dimensional numerical test cases are included in this paper, which validate the application of these schemes to relativistic multi-component flows.展开更多
Mixed ionic-electronic conductors(MIECs)play a crucial role in the landscape of energy conversion and storage technologies,with a pronounced focus on electrode materials’application in solid oxide fuel cells(SOFCs)an...Mixed ionic-electronic conductors(MIECs)play a crucial role in the landscape of energy conversion and storage technologies,with a pronounced focus on electrode materials’application in solid oxide fuel cells(SOFCs)and proton-conducting ceramic fuel cells(PCFCs).In parallel,the emergence of semiconductor ionic materials(SIMs)has introduced a new paradigm in the field of functional materials,particularly for both electrode and electrolyte development for low-temperature,300–550℃,SOFCs,and PCFCs.This review article critically delves into the intricate mechanisms underpinning the synergistic relationship between MIECs and SIMs,with a particular emphasis on elucidating the fundamental working principles of semiconductor ionic membrane fuel cells(SIMFCs).By exploring critical facets such as ion-coupled electron transfer/transport,junction effect,energy bands alignment,and theoretical computations,it casts an illuminating spotlight on the transformative potential of MIECs,also involving triple charge conducting oxides(TCOs)in the context of SIMs and advanced fuel cells(FCs).The insights and findings articulated herein contribute substantially to the advancement of SIMs and SIMFCs by tailoring MIECs(TCOs)as promising avenues toward the emergence of high-performance SIMFCs.This scientific quest not only addresses the insistent challenges surrounding efficient charge transfer,ionic transport and power output but also unlocks the profound potential for the widespread commercialization of FC technology.展开更多
Coronavirus disease(COVID-19)is a serious respiratory disease that spreads through the coronavirus globally.It soon became a pandemic after its appearance in 2019 and demanded new techniques for its identification and...Coronavirus disease(COVID-19)is a serious respiratory disease that spreads through the coronavirus globally.It soon became a pandemic after its appearance in 2019 and demanded new techniques for its identification and detection.Owing to this situation,RT-LAMP appears to be a novel method for the identification of COVID-19 because of its vast applications,including cost-effectiveness and time-saving.This research highlights the use of RT-LAMP,a more sensitive test than RT-PCR,for the assessment of SARS-CoV-2,the severe acute respiratory illness.To identify the spike(S)and NSP1 protein using RT-LAMP,170 total samples of coronavirus-suspected patients were served in this research.Health certifications and bioethical considerations were taken into consideration.After the sample was extracted from the patient's swabs,RNA was isolated,extracted,and purified.The response was then run on the RT-LAMP at the ideal temperature,and the outcomes could be observed with the unaided eye as they changed from pink to yellow.It is a simple method of determining if the test is positive or negative.For this purpose,both RT-LAMP and RT-PCR tests are used during these procedures.Genes linked with COVID-19 testing including S,nspl,and ORF are suited to coronavirus testing;they have 100%specificity and low sensitivity,but S has more specificity and sensitivity than nspl and ORF,respectively.Out of the 95 positive samples,89(93.68%)samples yielded favorable outcomes utilizing RT-LAMP,while 55 negative samples yielded 100%positive results.The present research demonstrates that RT-LAMP is less sensitive yet more selective for coronavirus detection.展开更多
Solid-state sodium metal batteries utilizing inorganic solid electrolytes(SEs)hold immense potentials such as intrinsical safety,high energy density,and environmental sustainability.However,the interfacial inhomogenei...Solid-state sodium metal batteries utilizing inorganic solid electrolytes(SEs)hold immense potentials such as intrinsical safety,high energy density,and environmental sustainability.However,the interfacial inhomogeneity/instability at the anode-SE interface usually triggers the penetration of sodium dendrites into the electrolyte,leading to short circuit and battery failure.Herein,confronting with the original nonuniform and high-resistance solid electrolyte interphase(SEI)at the Na-Na_(3)Zr_(2)Si_(2)PO_(12)interface,an oxygen-regulated SEI innovative approach is proposed to enhance the cycling stability of anode-SEs interface,through a spontaneous reaction between the metallic sodium(containing trace amounts of oxygen)and the Na_(3)Zr_(2)Si_(2)POi_(2)SE.The oxygen-regulated spontaneous SEI is thin,uniform,and kinetically stable to facilitate homogenous interfacial Na^+transportation,Benefitting from the optimized SEI,the assembled symmetric cell exhibits an ultra-stable sodium plating/stripping cycle for over 6600 h under a practical capacity of 3 mAh cm^(-2).Qua si-sol id-state batteries with Na_(3)V_(2)(PO_(4))_(3)cathode deliver excellent cyclability over 500 cycles at a rate of 0.5 C(1 C=117 mA cm^(-2))with a high capacity retention of95.4%.This oxygen-regulated SEI strategy may offer a potential avenue for the future development of high-energy-density solid-state metal batteries.展开更多
The versatile,and tunable surface chemistry of two-dimensional(2D)MXenes coupled with their distinct properties including hydrophilic nature,favorable ion transport and metallic conductivity make them an ideal candida...The versatile,and tunable surface chemistry of two-dimensional(2D)MXenes coupled with their distinct properties including hydrophilic nature,favorable ion transport and metallic conductivity make them an ideal candidate for energy storage devices.Modifying surface terminations by doping heteroatom is an efficient approach to improve layer spacing and electrochemical active sites of the MXenes.However,nitrogen doping in 2D materials has been an effective way to enhance their electrochemical characteristics.In this study,N-Nb_(2)CT_(x) MXene was synthesized by utilizing the hydrothermal method in which nitrogen doping in MXene was confirmed through several characterization techniques.Tuning of MXene surface by a cost-effective strategy has shown improved performance for energy storage.After doping nitrogen in Nb_(2)CT_(x) MXene,it has shown enhanced pseudocapacitance performance in 1 M potassium hydroxide(KOH),elevating the electrochemical properties.N-Nb_(2)CT_(x) MXene has displayed a better specific capacitance of up to 640 F·g^(-1) while pristine Nb_(2)CT_(x) MXene has shown 276 F·g^(-1) from the cyclic voltammogram(CV)at a scan rate of 5 mV·s^(-1).In addition,an asymmetric device of activated carbon/N-Nb_(2)CT_(x) was assembled for real-world applications,it has exhibited refined results.The asymmetric device has shown remarkable cyclic stability of 90%capacity retention at a current density of 5 A·g^(-1) for 5000 cycles.Additionally,the detailed density functional theory(DFT)calculations support the stability of nitrogen replacing the fluorine functional group,complementing the experiment.展开更多
CONSPECTUS:With the development of nanotechnology and characterization techniques,it has been realized that the reactivity of metal nanoparticles mainly depends on some unsaturated coordination atoms on the surface.Ho...CONSPECTUS:With the development of nanotechnology and characterization techniques,it has been realized that the reactivity of metal nanoparticles mainly depends on some unsaturated coordination atoms on the surface.However,only a small fraction of the surface exposed atoms can access the reactants and act as reactive sites,resulting in low utilization of metal atoms.Moreover,due to the complex structure of metal nanoparticles,the metal atoms exposed on the surface are likely to be in different chemical environments and may act as multiple active centers to catalyze the reactants,which brings great difficulties in the establishment of the structure−activity relationship of metal nanoparticles.展开更多
Binary metal chalcogenides(BMCs)have shown better electrochemical performance compared with their mono metal counterparts owing to their abundant phase interfaces,higher active sites,faster electrochemical kinetics an...Binary metal chalcogenides(BMCs)have shown better electrochemical performance compared with their mono metal counterparts owing to their abundant phase interfaces,higher active sites,faster electrochemical kinetics and higher electronic conductivity.Nevertheless,their performance still undergoes adverse decline during electrochemical processes mainly due to poor intrinsic ionic conductivities,large volume expansions,and structural agglomeration and fracture.To tackle these problems,various strategies have been applied to engineer the BMC nanostructures to obtain optimized electrode materials.However,the lack of understanding of the electrochemical response of BMCs still hinders their large-scale application.This review not only highlights the recent progress and development in the preparation of BMC-based electrode materials but also explains the kinetics to further understand the relation between structure and performance.It will also explain the engineering of BMCs through nanostructuring and formation of their hybrid structures with various carbonaceous materials and three-dimensional(3 D)templates.The review will discuss the detailed working mechanism of BMC-based nanostructures in various electrochemical energy storage(EES)systems including supercapacitors,metal-ion batteries,metal-air batteries,and alkaline batteries.In the end,major challenges and prospective solutions for the development of BMCs in EES devices are also outlined.We believe that the current review will provide a guideline for tailoring BMCs for better electrochemical devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant Number 22350410379)Zhejiang Provincial Natural Science Foundation of China(LZ23B030003)+1 种基金the Fundamental Research Funds for the Central Universities(226-202400075)Ten Thousand Talent Program of Zhejiang Province.
文摘Separator modification is an effective approach to suppress dendrite growth to realize high-energy sodium metal batteries(SMBs)in practical applications,however,its success is mainly subject to surface modification.Herein,a separator with multifunctional layers composed of N-doped mesoporous hollow carbon spheres(HCS)as the inner layer and sodium fluoride(NaF)as the outer layer on commercial polypropylene separator(PP)is proposed(PP@HCS-NaF)to achieve stable cycling in SMB.At the molecular level,the inner HCS layer with a high content of pyrrolic-N induces the uniform Na^(+)flux as a potential Na^(+)redistributor for homogenous deposition,whereas its hollow mesoporous structure offers nanoporous buffers and ion channels to regulate Na^(+)ion distribution and uniform deposition.The outer layer(NaF)constructs the NaF-enriched robust solid electrolyte interphase layer,significantly lowering the Na^(+)ions diffusion barrier.Benefiting from these merits,higher electrochemical performances are achieved with multifunctional double-layered PP@HCS-NaF separators compared with single-layered separators(i.e.PP@HCS or PP@NaF)in SMBs.The Na‖Cu half-cell with PP@HCS-NaF offers stable cycling(280 cycles)with a high CE(99.6%),and Na‖Na symmetric cells demonstrate extended lifespans for over 6000 h at 1 mA cm^(-2)with a progressively stable overpotential of 9 mV.Remarkably,in Na‖NVP full-cells,the PP@HCS-NaF separator grants a stable capacity of~81 mA h g^(-1)after 3500 cycles at 1 C and an impressive rate capability performance(~70 mA h g^(-1)at 15 C).
基金supported by the Jiangsu Fundamental Research Program(JSSCRC2021491)Ongoing Research Funding Program(ORF-2025-391)。
文摘Searching for compatible electrolytes with Ni_(0.8)C_(00.15)Al_(0.05)LiO_(2-δ)(NCAL)electrodes that exhibit high ionic conductivity at low operational temperatures(<550℃)is crucial for advancing ceramics fuel cells(CFCs)research.In this work,the experimental and theoretical analyses demonstrate that the highly stable single-phase Gd_(3)Ga_(5)O_(12)(GGO)garnet structure,composed of Gd-O octahedrons and Ga-O tetrahedrons,provides more active sites for ion transport,resulting in enhanced peak power density(PPD)and stable open circuit voltage(OCV)at low operational temperatures.The unique internal garnet structure effectively reduces the interfacial impedance of the prepared fuel cell device,provides more active sites at triple-phase boundarie region,and increases the electrochemical stability.As a result,the constructed fuel cell device can deliver a superior peak power density of 770 mW/cm^(2)at 490℃.In addition,X-ray photoelectron spectroscopy,electrochemical impedance spectroscopy,and theoretical calculations further demonstrate electrolyte effectiveness of GGO,enabling stable an OCV even at a low temperature of 370℃under a H_(2)/air environment.This work contributes to a deeper understanding of the underlying mechanisms of a single-layer fuel cell device,which is essential for advancing this promising energy technology,even at a very low temperature of 370℃.
基金Project supported by the Scientific and Technological Innovation Team of Nanjing(NINGJIAOGAOSHI 2021 No.16)。
文摘Enhancing the electrocatalytic activity of the electrode materials,specifically oxygen reduction reaction(ORR),at lower operating temperatures(<600℃)is the prime rank to realize the commercialization of solid oxide fuel cells(SOFCs)research.Herein,a new hexagonal structure-based cathode material was developed with the co-doping of Gd_(2)O_(3)and Cr_(2)O_(3)of parent SrFe_(12)O_(19)oxide,respectively.At 550-475℃,Sr_(0.90)Gd_(0.10)Fe_(11.90)Cr_(0.10)O_(19)(SFO-10)cathode sample leading to the large peak power density(PPD)of 395 mW/cm^(2),has appropriate surface oxygen defects(O_(β))up to 17%,as verified by X-ray photoelectron microscopy(XPS).Theoretical calculations reveal that the co-doping of Gd and Cr oxides creates lattice disorder at the hexagonal lattice,which decreases the energy barrier for ion transport and enhances the electrocatalytic characteristics of ORR.Consequently,the SFO-10 cathode shows a favorable ORR activity with the least lower polarization resistance(ASR)at 550℃with gadolinium-doped ceria(GDC)electrolyte.This work provides a self-assembled single-phase hexagonal cathode to accelerate the lowtemperature hindrance of SOFC technology.
基金Project supported by the Industry-University-Research Cooperation Project of Jiangsu Province in China (BY2021057)the Qing Lan Project of Jiangsu Province (BY2021011)Jiangsu Province Higher Vocational College Young Teachers Enterprise Practice Training Funding Project (2021QYSJ048)。
文摘Rare earth(RE)low doping has a significant influence on the structural,morphological,and magnetic properties of spinel ferrite nanoparticles.Therefore,rare earth neodymium(Nd)oxide was fully doped into spinel ferrite with a composition of Co_(0.80)Ni_(0.20)Nd_xFe_(2-x)O_4(x=0.0,0.05,0.10,and 0.15)using the sol-gel auto combustion method.Structural analysis of the synthesized samples with low doping of Nd using X-ray diffraction(XRD)and Rietveld refinements reveals a pure single-phase cubic structure,while the second phase appears with increasing content of Nd^(3+)at x=0.10 and 0.15.Scanning electron microscopy(SEM)and high-resolution transmission electron microscopy(HR-TEM)show well-shaped spherical grains within the nanometer range of the pure Co_(0.80)Ni_(0.20)Fe_(2)O_(4) sample,while larger grains with the presence of agglomeration are observed with doping of Nd^(3+)into the spinel ferrite nanoparticles.The magnetic parameters,i.e.,saturation magnetization M_s,remanence and magnetic moments exhibit decreasing trend with Nd^(3+)doping and M_s values are in 65.69 to 53.34 emu/g range.The coercivity of the Nd-doped Co-Ni spinel ferrite sample was calculated to be 1037.76 to~827.24 Oe.This work demonstrates remarkable improvements in the structural and magnetic characteristics of Nddoped Co-Ni spinel ferrite nanoparticles for multiple versatile applications.
基金the Researcher Supporting Project number (RSP-2020/61),King Saud University,Riyadh,Saudi Arabia for the financial support。
文摘Rare earths(REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications.In the present study,the nanoferrites of CuRE0.02Fe1.98O4,where REs=Y^(3+),Yb^(3+),Gd^(3+),were prepared using one step sol-gel method.The prepared samples are copper ferrite(CFO),yttrium doped copper ferrite(Y-CFO),ytterbium doped copper ferrite(Yb-CFO) and gadolinium doped copper ferrite(Gd-CFO),respectively.The single-phase structure of all the REs doped nanoferrites was determined by X-ray diffraction(XRD) analysis.The porosity,agglomerations and grain size of the REs doped copper ferrite were examined using field emission scanning electron microscopy(FESEM) analysis.Fourier transform infrared spectroscopy(FTIR)elaborates the phase formation and environmental effects on the REs doped nanoparticles(NPs).The recorded room temperature M-H loops from a vibrating sample magnetometer(VSM) elucidate the magnetic properties of the REs doped spinel nanoferrites.The magnetic saturation(Ms) was calculated in the range of 23.08 to 51.78 emu/g.The calculated coercivity values(272.6 to 705.60 Oe) confirm the soft magnetic behavior of REs doped copper ferrites.Furthermore,the electromagnetic and dielectric properties were assessed using a Vector network analyzer(VNA) from 1 to 6 GHz.The permeability,permittivity,dielectric tangent loss and electric modulus of the REs doped spinel ferrites illustrate that the prepared NPs may be suitable for microwave and high frequency applications.
文摘Quantitative security metrics are desirable for measuring the performance of information security controls. Security metrics help to make functional and business decisions for improving the performance and cost of the security controls. However, defining enterprise-level security metrics has already been listed as one of the hard problems in the Info Sec Research Council's hard problems list. Almost all the efforts in defining absolute security metrics for the enterprise security have not been proved fruitful. At the same time, with the maturity of the security industry, there has been a continuous emphasis from the regulatory bodies on establishing measurable security metrics. This paper addresses this need and proposes a relative security metric model that derives three quantitative security metrics named Attack Resiliency Measure(ARM), Performance Improvement Factor(PIF), and Cost/Benefit Measure(CBM) for measuring the performance of the security controls. For the effectiveness evaluation of the proposed security metrics, we took the secure virtual machine(VM) migration protocol as the target of assessment. The virtual-ization technologies are rapidly changing the landscape of the computing world. Devising security metrics for virtualized environment is even more challenging. As secure virtual machine migration is an evolving area and no standard protocol is available specifically for secure VM migration. This paper took the secure virtual machine migration protocol as the target of assessment and applied the proposed relative security metric model for measuring the Attack Resiliency Measure, Performance Improvement Factor, and Cost/Benefit Measure of the secure VM migration protocol.
文摘With an ever increasing energy demand and environmental issues,many state-of-the-art nanostructured electrode materials have been developed for energy storage devices and they include batteries,supercapacitors and fuel cells.Among these electrode materials,L-TMD(layered transition metal dichalcogenide)nanosheets(especially,S(sulfur)and Se(selenium)based dichaleogenides)have received a lot of attention due to their intriguing layered structure for enhanced electrochemical properties.L-TMD composites have recently been investigated not only as a main charge storage specie but also,as a substrate to hold the active specie.This review highlights the recent advancements in L-TMD composites with 0D(0-dimensional),1 D,2D,3D and various forms of carbon structures and their potential applications in LIB(lithium ion battery)and SIB(sodium ion battery).
文摘Rationale:SARS-CoV-2 has been identified as a highly infective and contagious viral infection.The SARS-CoV-2 pandemic has been spread worldwide and affected more than 210 countries.Globally,the fast spread of novel SARS-CoV-2 variants has been mostly attributed to international travel.Patient concerns:We are reporting the genomic evidence of SARSCoV-2 Eta VOI among two international travelers.Both travelers were males from Nigeria aged 24 and 34 years and both were asymptomatic.Diagnosis:The nasopharyngeal swab samples were in both travelers positive by real-time RT-PCR followed by COVIDSeq-NGS.Interventions:Paracetamol 3 times daily for 5 days.Outcomes:Patient recovered completely within 10 days and discharged after 14 days of quarantine duration.Lessons:This report highlights genomic variation of SARSCoV-2 among the travelers.For managing the present health crisis,molecular identification of viral variants present in different geographical locations will be very helpful.
文摘The dynamics of inviscid multi-component relativistic fluids may be modeled by the relativistic Euler equations, augmented by one (or more) additional species equation(s). We use the high-resolution staggered central schemes to solve these equations. The equilibrium states for each component are coupled in space and time to have a common temperature and velocity. The current schemes can handle strong shocks and the oscillations near the interfaces are negligible, which usually happens in the multi-component flows. The schemes also guarantee the exact mass conservation for each component, the exact conservation of total momentum, and energy in the whole particle system. The central schemes are robust, reliable, compact and easy to implement. Several one- and two-dimensional numerical test cases are included in this paper, which validate the application of these schemes to relativistic multi-component flows.
基金supported by the Science and Technology Department of Jiangsu Province under Grant(BE2022029)Jiangsu Provincial Innovation and Entrepreneurship Talent Program(JSSCRC2021491)+3 种基金Key Program for International S&T Cooperation Projects of Shaanxi Province(2019KWZ-03)Key Program for Nature Science Foundation of Shaanxi Province(2019JZ-20)Key Science and Technology Innovation Team of Shaanxi Province(2022TD-34)the Beijing Natural Science Foundation under Grant(IS23050)is greatly acknowledged.
文摘Mixed ionic-electronic conductors(MIECs)play a crucial role in the landscape of energy conversion and storage technologies,with a pronounced focus on electrode materials’application in solid oxide fuel cells(SOFCs)and proton-conducting ceramic fuel cells(PCFCs).In parallel,the emergence of semiconductor ionic materials(SIMs)has introduced a new paradigm in the field of functional materials,particularly for both electrode and electrolyte development for low-temperature,300–550℃,SOFCs,and PCFCs.This review article critically delves into the intricate mechanisms underpinning the synergistic relationship between MIECs and SIMs,with a particular emphasis on elucidating the fundamental working principles of semiconductor ionic membrane fuel cells(SIMFCs).By exploring critical facets such as ion-coupled electron transfer/transport,junction effect,energy bands alignment,and theoretical computations,it casts an illuminating spotlight on the transformative potential of MIECs,also involving triple charge conducting oxides(TCOs)in the context of SIMs and advanced fuel cells(FCs).The insights and findings articulated herein contribute substantially to the advancement of SIMs and SIMFCs by tailoring MIECs(TCOs)as promising avenues toward the emergence of high-performance SIMFCs.This scientific quest not only addresses the insistent challenges surrounding efficient charge transfer,ionic transport and power output but also unlocks the profound potential for the widespread commercialization of FC technology.
文摘Coronavirus disease(COVID-19)is a serious respiratory disease that spreads through the coronavirus globally.It soon became a pandemic after its appearance in 2019 and demanded new techniques for its identification and detection.Owing to this situation,RT-LAMP appears to be a novel method for the identification of COVID-19 because of its vast applications,including cost-effectiveness and time-saving.This research highlights the use of RT-LAMP,a more sensitive test than RT-PCR,for the assessment of SARS-CoV-2,the severe acute respiratory illness.To identify the spike(S)and NSP1 protein using RT-LAMP,170 total samples of coronavirus-suspected patients were served in this research.Health certifications and bioethical considerations were taken into consideration.After the sample was extracted from the patient's swabs,RNA was isolated,extracted,and purified.The response was then run on the RT-LAMP at the ideal temperature,and the outcomes could be observed with the unaided eye as they changed from pink to yellow.It is a simple method of determining if the test is positive or negative.For this purpose,both RT-LAMP and RT-PCR tests are used during these procedures.Genes linked with COVID-19 testing including S,nspl,and ORF are suited to coronavirus testing;they have 100%specificity and low sensitivity,but S has more specificity and sensitivity than nspl and ORF,respectively.Out of the 95 positive samples,89(93.68%)samples yielded favorable outcomes utilizing RT-LAMP,while 55 negative samples yielded 100%positive results.The present research demonstrates that RT-LAMP is less sensitive yet more selective for coronavirus detection.
基金Zhejiang Provincial Natural Science Foundation of China(LZ23B030003)the National Key R&D Program(2022YFB2502000)+1 种基金the National Key R&D Program(2022YFB2502000)the Fundamental Research Funds for the Central Universities(2021FZZX001-09)。
文摘Solid-state sodium metal batteries utilizing inorganic solid electrolytes(SEs)hold immense potentials such as intrinsical safety,high energy density,and environmental sustainability.However,the interfacial inhomogeneity/instability at the anode-SE interface usually triggers the penetration of sodium dendrites into the electrolyte,leading to short circuit and battery failure.Herein,confronting with the original nonuniform and high-resistance solid electrolyte interphase(SEI)at the Na-Na_(3)Zr_(2)Si_(2)PO_(12)interface,an oxygen-regulated SEI innovative approach is proposed to enhance the cycling stability of anode-SEs interface,through a spontaneous reaction between the metallic sodium(containing trace amounts of oxygen)and the Na_(3)Zr_(2)Si_(2)POi_(2)SE.The oxygen-regulated spontaneous SEI is thin,uniform,and kinetically stable to facilitate homogenous interfacial Na^+transportation,Benefitting from the optimized SEI,the assembled symmetric cell exhibits an ultra-stable sodium plating/stripping cycle for over 6600 h under a practical capacity of 3 mAh cm^(-2).Qua si-sol id-state batteries with Na_(3)V_(2)(PO_(4))_(3)cathode deliver excellent cyclability over 500 cycles at a rate of 0.5 C(1 C=117 mA cm^(-2))with a high capacity retention of95.4%.This oxygen-regulated SEI strategy may offer a potential avenue for the future development of high-energy-density solid-state metal batteries.
基金the Higher Education Commission(HEC)of Pakistan for providing research funding under Project No.:20-14784/NRPU/R&D/HEC/2021.S.A.K.acknowledge the QM4ST project financed by the Ministry of Education of the Czech Republic grant no.CZ.02.01.01/00/22_008/0004572,co-funded by the European Regional Development Fund.
文摘The versatile,and tunable surface chemistry of two-dimensional(2D)MXenes coupled with their distinct properties including hydrophilic nature,favorable ion transport and metallic conductivity make them an ideal candidate for energy storage devices.Modifying surface terminations by doping heteroatom is an efficient approach to improve layer spacing and electrochemical active sites of the MXenes.However,nitrogen doping in 2D materials has been an effective way to enhance their electrochemical characteristics.In this study,N-Nb_(2)CT_(x) MXene was synthesized by utilizing the hydrothermal method in which nitrogen doping in MXene was confirmed through several characterization techniques.Tuning of MXene surface by a cost-effective strategy has shown improved performance for energy storage.After doping nitrogen in Nb_(2)CT_(x) MXene,it has shown enhanced pseudocapacitance performance in 1 M potassium hydroxide(KOH),elevating the electrochemical properties.N-Nb_(2)CT_(x) MXene has displayed a better specific capacitance of up to 640 F·g^(-1) while pristine Nb_(2)CT_(x) MXene has shown 276 F·g^(-1) from the cyclic voltammogram(CV)at a scan rate of 5 mV·s^(-1).In addition,an asymmetric device of activated carbon/N-Nb_(2)CT_(x) was assembled for real-world applications,it has exhibited refined results.The asymmetric device has shown remarkable cyclic stability of 90%capacity retention at a current density of 5 A·g^(-1) for 5000 cycles.Additionally,the detailed density functional theory(DFT)calculations support the stability of nitrogen replacing the fluorine functional group,complementing the experiment.
基金supported by the National Key R&D Program of China(No.2021YFA1501001)the National Science Fund for Distinguished Young Scholars(No.52025133)+1 种基金the Beijing Natural Science Foundation(Z220020)Tencent Foundation through the XPLORER PRIZE,CNPC Innovation Found(2021DQ02-1002).
文摘CONSPECTUS:With the development of nanotechnology and characterization techniques,it has been realized that the reactivity of metal nanoparticles mainly depends on some unsaturated coordination atoms on the surface.However,only a small fraction of the surface exposed atoms can access the reactants and act as reactive sites,resulting in low utilization of metal atoms.Moreover,due to the complex structure of metal nanoparticles,the metal atoms exposed on the surface are likely to be in different chemical environments and may act as multiple active centers to catalyze the reactants,which brings great difficulties in the establishment of the structure−activity relationship of metal nanoparticles.
基金supported by the National Natural Science Fund for Distinguished Young Scholars(52025133)the Tencent Foundation through the XPLORER PRIZE,Beijing Natural Science Foundation(JQ18005)+2 种基金the National Natural Science Foundation of China(52125307 and 11974023)the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnic University(NWPU)(SKLSP202004)the Key Area R&D Program of Guangdong Province(2018B030327001 and 2018B010109009)。
文摘Binary metal chalcogenides(BMCs)have shown better electrochemical performance compared with their mono metal counterparts owing to their abundant phase interfaces,higher active sites,faster electrochemical kinetics and higher electronic conductivity.Nevertheless,their performance still undergoes adverse decline during electrochemical processes mainly due to poor intrinsic ionic conductivities,large volume expansions,and structural agglomeration and fracture.To tackle these problems,various strategies have been applied to engineer the BMC nanostructures to obtain optimized electrode materials.However,the lack of understanding of the electrochemical response of BMCs still hinders their large-scale application.This review not only highlights the recent progress and development in the preparation of BMC-based electrode materials but also explains the kinetics to further understand the relation between structure and performance.It will also explain the engineering of BMCs through nanostructuring and formation of their hybrid structures with various carbonaceous materials and three-dimensional(3 D)templates.The review will discuss the detailed working mechanism of BMC-based nanostructures in various electrochemical energy storage(EES)systems including supercapacitors,metal-ion batteries,metal-air batteries,and alkaline batteries.In the end,major challenges and prospective solutions for the development of BMCs in EES devices are also outlined.We believe that the current review will provide a guideline for tailoring BMCs for better electrochemical devices.
