Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials ...Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials for ASIBs,Na_(3)V_(2)(PO_(4))_(3)(NVP) exhibits excellent structural stability and a high Na+diffusion coefficient,making it a promising option.However,the high solubility of vanadium-based materials in aqueous electrolytes engenders suboptimal cycling stability for Na_(3)V_(2)(PO_(4))_(3),constraining its application in ASIBs.Herein,the Cr-substituted Na_(3)V_(1.3)Cr_(0.7)(PO_(4))3@C(NV_(1.3)Cr_(0.7)P) cathode material was synthesized via a simple sol-gel method.It is found that Cr substitution reduces the cell parameters of NV_(1.3)Cr_(0.7)P,effectively reinforcing the crystal structure.Furthermore,NV_(1.3)Cr_(0.7)P alters the Na^(+)insertion/extraction mechanism,transforming the typical two-phase reaction between Na_(1)V_(2)(PO_(4))_(3)and Na_(3)V_(2)(PO_(4))3into continuous solid-solution reactions with stable intermediates.The Cr substitution diminishes the sodium-ion diffusion energy barrier in NV_(1.3)Cr_(0.7)P,leading to smoother Na+insertion and extraction processes.Consequently,NV_(1.3)Cr_(0.7)P exhibits impressive cycling stability,retaining 74.8% of its capacity after 5,000 cycles at a current density of 5 A g^(-1),along with an outstanding rate performance of 79,2% at 10 A g^(-1).This work elucidates the stable Na^(+)insertion/extraction processes in Cr-substituted NV_(1.3)Cr_(0.7)P,offering insights into the application of vanadium-based materials in aqueous sodium-ion batteries.展开更多
Slow-release phosphate materials were prepared by activating insoluble phosphate with organic acid to stabilize high concentrations of Cd and Zn in contaminated smelter soil.The results showed that oxalic acid(0.1 mol...Slow-release phosphate materials were prepared by activating insoluble phosphate with organic acid to stabilize high concentrations of Cd and Zn in contaminated smelter soil.The results showed that oxalic acid(0.1 mol/L)activated tricalcium phosphate(TO-0.1)provided the most efficient stabilization of Cd and Zn.After 30 d treatment,leaching concentrations of Cd and Zn in soil were decreased from 3.17 and 16.60 mg/L to 0.078 and 0.32 mg/L,respectively.The acid-soluble fractions of Cd and Zn were transformed into reducible,oxidizable,and residual fractions.Notably,As mobility in TO-0.1 treated soils did not increase.In addition,acid rain leaching and 150 d of natural aging revealed that the slow-release phosphate material provided long-term stability for the stabilization of Cd and Zn.This study verifies the potential application of slow-release phosphate materials for the remediation of heavy metal contaminated soil at smelting sites.展开更多
A new Ag/AgCl sensor for measuring marine electric fields was prepared and characterized through electrochemical methods and scanning electron microscopy.Its performance was evaluated in both laboratory and deep-water...A new Ag/AgCl sensor for measuring marine electric fields was prepared and characterized through electrochemical methods and scanning electron microscopy.Its performance was evaluated in both laboratory and deep-water settings.The study indicates that the double-pulse electrodeposition method is advantageous for producing Ag/AgCl sensors that maintain excellent stability over time.During a 20-day continuous stability test,the potential difference of the sensor consistently remained between -24.76μV and 62.07μV,with a minimum potential difference drift of 2.77μV per 24 h.All sensors accurately detected artificial signals in both the time and frequency domains,and their responses were consistent with one another.The minimum noise level of the sensor was 0.59 nV(√Hz)^(-1)@1 Hz.The sensor performed well in high-precision electric field measurements at a depth of approximately 2800 m in the South China Sea.The high stability and low noise level of the sensor make it an effective tool for detecting electrical conductivity structures beneath the seafloor.展开更多
Thin films of ternary compounds CuxlnyN and CuxTiyN were grown by magnetron sputtering to improve the thermal stability of Cu3N, a material that decomposes below 300 ℃, and thus promises many interesting applications...Thin films of ternary compounds CuxlnyN and CuxTiyN were grown by magnetron sputtering to improve the thermal stability of Cu3N, a material that decomposes below 300 ℃, and thus promises many interesting applications in directwriting. The effect of In or Ti incorporation in altering the structure and physical properties of copper nitride was evaluated by characterizing the film structure, surface morphology, and temperature dependence of electrical resistivity. More Ti than In can be accommodated by copper nitride without completely deteriorating the Cu3N lattice. A small amount of In or Ti can improve the crystallinity, and consequently the surface morphology. While the decomposition temperature is rarely influenced by In, the Ti-doped sample, Cu59.31Ti2.64N38.05, shows an X-ray diffraction pattern dominated by characteristic Cu3N peaks, even after annealing at 500 ℃. Both In and Ti reduce the bandgap of the original Cu3N phase, resulting in a smaller electrical resistivity at room temperature. The samples with more Ti content manifest metal-semiconductor transition when cooled from room temperature down to 50 K. These results can be useful in improving the applicability of copper-nitride-based thin films.展开更多
The synthesis, characterization, thermal degradation and stability of polyaniline （PANI）, poly（m-nitroaniline）, poly（m-chloroaniline） and poly（o-methylaniline） were reported. Different properties were measured...The synthesis, characterization, thermal degradation and stability of polyaniline （PANI）, poly（m-nitroaniline）, poly（m-chloroaniline） and poly（o-methylaniline） were reported. Different properties were measured and compared with PANI to find out the effect of electron donating groups （-CH3） and electron withdrawing groups （-Cl, -NO2）. It was found that the presence of any type of substitution in the benzene ring of aniline increased the solubility but reduced the yield, thermal stability and electrical conductivity. Two probe methods were used to measure the electrical conductivity of these polymers. The structural properties of these polymers were characterized by using FTIR and UV-Vis spectroscopic methods. Thermal degradation and stability of these polymers were explained by using thermogravimetric analysis （TGA） and conductivity measurements.展开更多
The structural stability and electrical properties of AlB2-type MnB2 were studied based on high pressure angledispersive x-ray diffraction, in situ electrical resistivity measured in a diamond anvil cell(DAC) and firs...The structural stability and electrical properties of AlB2-type MnB2 were studied based on high pressure angledispersive x-ray diffraction, in situ electrical resistivity measured in a diamond anvil cell(DAC) and first-principles calculations under high pressure. The x-ray diffraction results show that the structure of AlB2-type MnB2 remains stable up to 42.6 GPa. From the equation of state of MnB2, we obtained a bulk modulus value of 169.9±3.7 GPa with a fixed pressure derivative of 4, which indicates that AlB2-type MnB2 is a hard and incompressible material. The electrical resistance undergoes a transition at about 19.3 GPa, which can be explained by a transition of manganese 3d electrons from localization to delocalization under high pressure.展开更多
The influences of curing time, the content of free evaporable water in cement paste, environmental temperature, and alternative heating and cooling on the electrical resistance of high content carbon fiber reinforced ...The influences of curing time, the content of free evaporable water in cement paste, environmental temperature, and alternative heating and cooling on the electrical resistance of high content carbon fiber reinforced cement (CFRC) paste are studied by experiments with specimens of Portland cement 42.5 with 10 mm PAN-based carbon fiber and methylcellulose. Experimental results indicate that the electrical resistance of CFRC increases relatively by 24% within a hydration time of 90 d and almost keeps constant after 14 d, changes hardly with the mass loss of free evaporable water in the concrete dried at 50 °C, increases relatively by 4% when ambient temperature decreases from 15 °C to ?20 °C, and decreases relatively by 13% with temperature increasing by 88 °C. It is suggested that the electric resistance of the CFRC is stable, which is testified by the stable power output obtained by electrifying the CFRC slab with a given voltage. This implies that such kind of high content carbon fiber reinforced cement composite is potentially a desirable electrothermal material for airfield runways and road surfaces deicing.展开更多
In this paper, a robust controller for electrically driven robotic systems is developed. The controller is designed in a backstepping manner. The main features of the controller are: 1) Control strategy is developed a...In this paper, a robust controller for electrically driven robotic systems is developed. The controller is designed in a backstepping manner. The main features of the controller are: 1) Control strategy is developed at the voltage level and can deal with both mechanical and electrical uncertainties. 2) The proposed control law removes the restriction of previous robust methods on the upper bound of system uncertainties. 3) It also benefits from global asymptotic stability in the Lyapunov sense. It is worth to mention that the proposed controller can be utilized for constrained and nonconstrained robotic systems. The effectiveness of the proposed controller is verified by simulations for a two link robot manipulator and a four-bar linkage. In addition to simulation results,experimental results on a two link serial manipulator are included to demonstrate the performance of the proposed controller in tracking a given trajectory.展开更多
The functionality of wood has evolved with time to adapt to the emerging needs of society.Carbonized wood-based composites have attracted tremendous interest in the fields of aerospace,military power,electric power,an...The functionality of wood has evolved with time to adapt to the emerging needs of society.Carbonized wood-based composites have attracted tremendous interest in the fields of aerospace,military power,electric power,and system electronic devices,especially at high temperatures.Nevertheless,their electrical conductivity and thermal stability characteristics are still far from satisfactory.Herein,an innova-tive wood-derived carbon-carbon nanotubes-pyrolytic carbon composites(WDC-CNTs-PyCs)is successfully fabricated by chemical vapor deposition and chemical vapor infiltration.The combination of wood-derived carbon(WDC),carbon nanotubes(CNTs),and pyrolytic carbon(PyC)has never been reported in any previous work.We have innovatively introduced PyC into the WDC by chemical vapor infiltration.CNTs promote the continuous deposition of PyC to form dense structures.WDC-CNTs-PyC demonstrates significant compressive strength(85.4 MPa)and excellent electrical conductivity(632 S cm^(-1)).The weight loss rate of WDC-CNTs-PyC is 6%after heating at 500℃ for 10 min in the air atmosphere.Furthermore,WDC-CNTs-PyC could resist oxyacetylene ablation above 2300℃ for 15 s.With excellent electrical conductivity,outstanding thermal stability,and mechanical properties,WDC-CNTs-PyC opens up a surprising strategy for efficiently fabricating various high-performance electronic device composites that could be used in high-temperature fields.展开更多
Using a recently established liquid crystal model for vesicles, we present a theoretical method to analyze the morphological stability of liquid crystal vesicles in an electric field. The coupled mechanical-electrical...Using a recently established liquid crystal model for vesicles, we present a theoretical method to analyze the morphological stability of liquid crystal vesicles in an electric field. The coupled mechanical-electrical effects associated with elastic bending, osmotic pressure, surface tension, Max- well pressure, as well as flexoelectric and dielectric proper- ties of the membrane are taken into account. The first and second variations of the free energy are derived in a com- pact form by virtue of the surface variational principle. The former leads to the shape equation of a vesicle embedded in an electric field, and the latter allows us to examine the stabil- ity of a given vesicle morphology. As an illustrative exam- ple, we analyze the stability of a spherical vesicle under a uniform electric field. This study is helpful for understanding and revealing the morphological evolution mechanisms of vesicles in electric fields and some associated phenomena of cells.展开更多
Effect of electrode insulation on the electric field and the flow field of the machining gap during electrochemical drilling（ECD） is numerically studied. Electric field simulation shows that the current density alon...Effect of electrode insulation on the electric field and the flow field of the machining gap during electrochemical drilling（ECD） is numerically studied. Electric field simulation shows that the current density along the side gap decreases with increasing the thickness of electrode insulation. And the analysis of the electrolyte flow in the frontal gap shows that the insulation thickness has a remarkable influence on the pressure distributions. Ex- periments investigate the influence of the insulation thickness on the main characteristics of the machined hole, i.e. , radial overcut, entrance conicity, and current stability. The poor hole is observed and identified as most likely to occur with a combination of the low tool feed rate and the low insulation thickness. The appropriate thickness of the insulating layer leads to an improvement on hole accuracy and machining stability.展开更多
Valtrate is the main drug quality control for the qualitative and quantitative analysis of Valerian medicines in the Chinese Pharmacopoeia 2010. However, valtrate is unstable under some conditions. We, for the first t...Valtrate is the main drug quality control for the qualitative and quantitative analysis of Valerian medicines in the Chinese Pharmacopoeia 2010. However, valtrate is unstable under some conditions. We, for the first time, systemically evaluated the stability of two bath reference standards （RS） by high performance liquid chromatography coupled with a triple quadrupole mass spectrometer （HPLC-MS/MS）. The forced degradations of valtrate were performed to evaluate its optimal storage, transportation and experiment conditions according to ICH guideline. The developed HPLC method was validated to determine the degradation products. Valtrate RS was sensitive to alkaline and thermal conditions, but it was relatively stable under acidic, oxidation and photolysis conditions. A total of nine degradation components were identified under alkaline hydrolysis （N1-N4） and thermal degradation （B1-B5）. The information obtained in this work would be valuable to minimize the decomposition of valtrate during the processes of preparation, storage, distribution and utilization. It was highly suggested to store valtrate with a single dose packing in brown closed ampoule at -20℃. Under the above-mentioned storage condition, valtrate could be stable for up to 3 years.展开更多
To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fe...To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis. The experiment consisted of 17 fertilizer treatments, containing the combinations of different N and P levels, with three replications arranged in a randomized complete block design. Nitrogen fertilizer was applied as urea, and P was applied as calcium superphosphate. Fertilizer rates had a large effect on the response of wheat yield to fertilization. Phosphorus, combined with N, increased yield significantly （P 〈 0.01）. In the unfertilized control and the N or P sole application treatments, wheat yield had a declining trend although it was not statistically significant. Stability analysis combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat.展开更多
An understanding of wheat yield and yield stability response to fertilization is important for sustainable wheat production. A 36-year long-term fertilization experiment was employed to evaluate the yield and yield st...An understanding of wheat yield and yield stability response to fertilization is important for sustainable wheat production. A 36-year long-term fertilization experiment was employed to evaluate the yield and yield stability of winter wheat. Five fertilization regimes were compared,including(1) CK, no fertilizer;(2) NPK, inorganic fertilizer only;(3) O, organic fertilizer only;(4)NPKO, 50% of NPK plus 50% of O, and(5) HNPKO, 80% of NPK plus 80% of O. The greatest yield increase was recorded in HNPKO, followed by NPKO, with O producing the lowest mean yield increase. Over the 36 years, the rate of wheat yield increase in fertilized plots ranged from95.31 kg ha-1 year-1 in the HNPKO to 138.65 kg ha-1 year-1 in the O. Yield stability analysis using the additive main effects and multiplicative interactions(AMMI) method assigned 62.3%, 26.3%,and 11.4% of sums of squares to fertilization effect, environmental effect, and fertilization ×environment interaction effect, respectively. The combination of inorganic and organic fertilization(NPKO and HNPKO) appeared to produce more stable yields than O or NPK, with lower coefficients of variation and AMMI stability value. However, wheat grown with O seemed to be the most susceptible to climate change and the least productive among the fertilized plots.Significant correlations of grain yield with soil properties and with mean air temperature were observed. These findings suggest that inorganic + organic fertilizer can increase wheat yield and its stability by improvement in soil fertility and reduction in variability to climate change.展开更多
Straw incorporation is a global common practice to improve soil fertility and rice yield.However,the effect of straw incorporation on rice yield stability is still unknown,especially under high fertilization level con...Straw incorporation is a global common practice to improve soil fertility and rice yield.However,the effect of straw incorporation on rice yield stability is still unknown,especially under high fertilization level conditions.Here,we reported the effect of straw returning on rice yield and yield stability under high fertilization levels in the rice–wheat system over nine years.The results showed that straw incorporation did not significantly affect the average rice yield of nine years.Straw incorporation reduced the coefficient of variation of rice yield by 25.8%and increased the sustainable yield index by 8.2%.The rice yield positively correlated with mean photosynthetically active radiation (PAR) of rice growth season and the effects of straw incorporation on rice yield depended on the PAR.Straw incorporation increased the rice yield by 5.4%in the low PAR years,whereas it did not affect the rice yield in the high PAR years.Long-term straw incorporation lowered soil bulk density but improved the soil organic matter,total N,available N,available P,and available K more strongly than straw removal.Our findings suggest that straw incorporation can increase rice yield stability through improving the resistance of rice plant growth to low PAR.展开更多
Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding in...Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding interactions of KGM were reduced after being treated with high-voltage pulse electric field,but there was no significant effect on its fiber chain form and thermal characteristics.Results of the study can provide a useful reference for further study on the structure and property of KGM,and especially can provide theoretical basis for the effect of physical field on the foodstuff deep processing related to KGM.展开更多
In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control ...In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.展开更多
Safe operation of electrochemical capacitors(supercapacitors)is hindered by the flammability of commercial organic electrolytes.Non-flammable Water-in-Salt(WIS)electrolytes are promising alternatives;however,they are ...Safe operation of electrochemical capacitors(supercapacitors)is hindered by the flammability of commercial organic electrolytes.Non-flammable Water-in-Salt(WIS)electrolytes are promising alternatives;however,they are plagued by the limited operation voltage window(typically≤2.3 V)and inherent corrosion of current collectors.Herein,a novel deep eutectic solvent(DES)-based electrolyte which uses formamide(FMD)as hydrogen-bond donor and sodium nitrate(NaNO_(3))as hydrogen-bond acceptor is demonstrated.The electrolyte exhibits the wide electrochemical stability window(3.14 V),high electrical conductivity(14.01 mScm^(-1)),good flame-retardance,anticorrosive property,and ultralow cost(7%of the commercial electrolyte and 2%of WIS).Raman spectroscopy and Density Functional Theory calculations reveal that the hydrogen bonds between the FMD molecules and NO_(3)^(-)ions are primarily responsible for the superior stability and conductivity.The developed NaNO_(3)/FMD-based coin cell supercapacitor is among the best-performing state-of-art DES and WIS devices,evidenced by the high voltage window(2.6 V),outstanding energy and power densities(22.77 Wh kg^(-1)at 630 W kg^(-1)and 17.37 kW kg^(-1)at 12.55 Wh kg^(-1)),ultralong cyclic stability(86%after 30000 cycles),and negligible current collector corrosion.The NaNO_(3)/FMD industry adoption potential is demonstrated by fabricating 100 F pouch cell supercapacitors using commercial aluminum current collectors.展开更多
In this paper, an improved air discharge fluid model under non-uniform electric field is constructed based on the plasma module COMSOL Multiphysics with artificial stability term, and the boundary conditions developed...In this paper, an improved air discharge fluid model under non-uniform electric field is constructed based on the plasma module COMSOL Multiphysics with artificial stability term, and the boundary conditions developed in the previous paper are applied to the calculation of photoionization rate. Based on the modified model, the characteristics of low temperature subatmospheric air discharge under 13 kV direct current voltage are discussed, including needle-plate and needle-needle electrode structures. Firstly, in order to verify the reliability of the model, a numerical example and an experimental verification were carried out for the modified model respectively. Both verification results show that the model can ensure the accuracy and repeatability of the calculation. Secondly, according to the calculation results of the modified model, under the same voltage and spacing, the reduced electric field under low temperature subatmosphere pressure is larger than that under normal temperature and atmospheric pressure. The high electric field leads to the air discharge at low temperature and sub atmospheric pressure entering the streamer initiation stage earlier, and has a faster propagation speed in the streamer development stage, which shortens the overall discharge time. Finally, the discharge characteristics of the two electrode structures are compared, and it is found that the biggest difference between them is that there is a pre-ionization region near the cathode in the needle-needle electrode structure. When the pre-ionization level reaches 1013 cm-3, the propagation speed of the positive streamer remains unchanged throughout the discharge process, and is no longer affected by the negative streamer. The peak value of electric field decreases with the increase of pre-ionization level, and tends to be constant during streamer propagation. Based on the previous paper, this paper constructs the air discharge model under non-uniform electric field, complements with the previous paper, and forms a relatively complete set of air discharge simulation system under low temperature and sub atmospheric pressure, which provides a certain reference for future research.展开更多
The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphi...The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphipathic molecule Triton X100(Triton) is modified on the NiO_(x)surface.The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiO_(x)surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiO_(x)/perovskite interface.Additionally,the hydrophobic chain of Triton protrudes from the NiO_(x)surface to prevent moisture from penetrating into the NiO_(x)/perovskite interface.Consequently,the NiO_(x)/Triton-based devices(MAPbI3as absorbing layer) show superior moisture and thermal stability,retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air(40%-50% relative humidity(RH)) at 25 ℃ for 1070 h and in N2at 85℃ for 800 h,respectively.Moreover,the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction capability.Besides,the NiO_(x)/Triton-based PSCs with Cs_(0.05)(MA_(0.15)FA_(0.85))_(0.95)Pb(I_(0.85)Br_(0.15))3perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices,indicating the viability of our strategies.Of particular note,a champion PCE of 22.35% and 20.46% was achieved for small-area(0.1 cm^(2)) and large-area(1.2 cm^(2)) NiO_(x)/Triton-based devices,respectively.展开更多
基金financially supported by the Scientific and Technological Plan Project of Guizhou Province ([2024]054)Additional support came from the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University (2020-520000-83-01324061)the Guizhou Engineering Research Center for Smart Services (2203-520102-04-04-298868)。
文摘Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials for ASIBs,Na_(3)V_(2)(PO_(4))_(3)(NVP) exhibits excellent structural stability and a high Na+diffusion coefficient,making it a promising option.However,the high solubility of vanadium-based materials in aqueous electrolytes engenders suboptimal cycling stability for Na_(3)V_(2)(PO_(4))_(3),constraining its application in ASIBs.Herein,the Cr-substituted Na_(3)V_(1.3)Cr_(0.7)(PO_(4))3@C(NV_(1.3)Cr_(0.7)P) cathode material was synthesized via a simple sol-gel method.It is found that Cr substitution reduces the cell parameters of NV_(1.3)Cr_(0.7)P,effectively reinforcing the crystal structure.Furthermore,NV_(1.3)Cr_(0.7)P alters the Na^(+)insertion/extraction mechanism,transforming the typical two-phase reaction between Na_(1)V_(2)(PO_(4))_(3)and Na_(3)V_(2)(PO_(4))3into continuous solid-solution reactions with stable intermediates.The Cr substitution diminishes the sodium-ion diffusion energy barrier in NV_(1.3)Cr_(0.7)P,leading to smoother Na+insertion and extraction processes.Consequently,NV_(1.3)Cr_(0.7)P exhibits impressive cycling stability,retaining 74.8% of its capacity after 5,000 cycles at a current density of 5 A g^(-1),along with an outstanding rate performance of 79,2% at 10 A g^(-1).This work elucidates the stable Na^(+)insertion/extraction processes in Cr-substituted NV_(1.3)Cr_(0.7)P,offering insights into the application of vanadium-based materials in aqueous sodium-ion batteries.
基金supported by the Natural Science Foundation of Hunan Province,China(No.2024JJ1012)the Postgraduate Innovative Project of Central South University,China(No.2023ZZTS0459)the National Key Research and Development Program of China(No.2019YFC1803605)。
文摘Slow-release phosphate materials were prepared by activating insoluble phosphate with organic acid to stabilize high concentrations of Cd and Zn in contaminated smelter soil.The results showed that oxalic acid(0.1 mol/L)activated tricalcium phosphate(TO-0.1)provided the most efficient stabilization of Cd and Zn.After 30 d treatment,leaching concentrations of Cd and Zn in soil were decreased from 3.17 and 16.60 mg/L to 0.078 and 0.32 mg/L,respectively.The acid-soluble fractions of Cd and Zn were transformed into reducible,oxidizable,and residual fractions.Notably,As mobility in TO-0.1 treated soils did not increase.In addition,acid rain leaching and 150 d of natural aging revealed that the slow-release phosphate material provided long-term stability for the stabilization of Cd and Zn.This study verifies the potential application of slow-release phosphate materials for the remediation of heavy metal contaminated soil at smelting sites.
基金supported by the National Natural Science Foundation of China(Nos.U23B20158,91958210,42004055)。
文摘A new Ag/AgCl sensor for measuring marine electric fields was prepared and characterized through electrochemical methods and scanning electron microscopy.Its performance was evaluated in both laboratory and deep-water settings.The study indicates that the double-pulse electrodeposition method is advantageous for producing Ag/AgCl sensors that maintain excellent stability over time.During a 20-day continuous stability test,the potential difference of the sensor consistently remained between -24.76μV and 62.07μV,with a minimum potential difference drift of 2.77μV per 24 h.All sensors accurately detected artificial signals in both the time and frequency domains,and their responses were consistent with one another.The minimum noise level of the sensor was 0.59 nV(√Hz)^(-1)@1 Hz.The sensor performed well in high-precision electric field measurements at a depth of approximately 2800 m in the South China Sea.The high stability and low noise level of the sensor make it an effective tool for detecting electrical conductivity structures beneath the seafloor.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51172272,10904165,and 11290161)the National Basic Research Program of China (Grant No. 2012CB933002)
文摘Thin films of ternary compounds CuxlnyN and CuxTiyN were grown by magnetron sputtering to improve the thermal stability of Cu3N, a material that decomposes below 300 ℃, and thus promises many interesting applications in directwriting. The effect of In or Ti incorporation in altering the structure and physical properties of copper nitride was evaluated by characterizing the film structure, surface morphology, and temperature dependence of electrical resistivity. More Ti than In can be accommodated by copper nitride without completely deteriorating the Cu3N lattice. A small amount of In or Ti can improve the crystallinity, and consequently the surface morphology. While the decomposition temperature is rarely influenced by In, the Ti-doped sample, Cu59.31Ti2.64N38.05, shows an X-ray diffraction pattern dominated by characteristic Cu3N peaks, even after annealing at 500 ℃. Both In and Ti reduce the bandgap of the original Cu3N phase, resulting in a smaller electrical resistivity at room temperature. The samples with more Ti content manifest metal-semiconductor transition when cooled from room temperature down to 50 K. These results can be useful in improving the applicability of copper-nitride-based thin films.
文摘The synthesis, characterization, thermal degradation and stability of polyaniline （PANI）, poly（m-nitroaniline）, poly（m-chloroaniline） and poly（o-methylaniline） were reported. Different properties were measured and compared with PANI to find out the effect of electron donating groups （-CH3） and electron withdrawing groups （-Cl, -NO2）. It was found that the presence of any type of substitution in the benzene ring of aniline increased the solubility but reduced the yield, thermal stability and electrical conductivity. Two probe methods were used to measure the electrical conductivity of these polymers. The structural properties of these polymers were characterized by using FTIR and UV-Vis spectroscopic methods. Thermal degradation and stability of these polymers were explained by using thermogravimetric analysis （TGA） and conductivity measurements.
基金Project supported by the National Basic Research Program of China （Grant No. 2011CB808200）, the Program for Changjiang Scholars and Innovative Re- search Team in University, China （Grant No. IRT1132）, the National Natural Science Foundation of China （Grant Nos. 51032001, 11074090, 10979001, and 51025206）, and the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences （Grant No. DE-AC02-98CH 10886）.
文摘The structural stability and electrical properties of AlB2-type MnB2 were studied based on high pressure angledispersive x-ray diffraction, in situ electrical resistivity measured in a diamond anvil cell(DAC) and first-principles calculations under high pressure. The x-ray diffraction results show that the structure of AlB2-type MnB2 remains stable up to 42.6 GPa. From the equation of state of MnB2, we obtained a bulk modulus value of 169.9±3.7 GPa with a fixed pressure derivative of 4, which indicates that AlB2-type MnB2 is a hard and incompressible material. The electrical resistance undergoes a transition at about 19.3 GPa, which can be explained by a transition of manganese 3d electrons from localization to delocalization under high pressure.
基金Funded by key project of the National Natural Science Foundation of China (50238040).
文摘The influences of curing time, the content of free evaporable water in cement paste, environmental temperature, and alternative heating and cooling on the electrical resistance of high content carbon fiber reinforced cement (CFRC) paste are studied by experiments with specimens of Portland cement 42.5 with 10 mm PAN-based carbon fiber and methylcellulose. Experimental results indicate that the electrical resistance of CFRC increases relatively by 24% within a hydration time of 90 d and almost keeps constant after 14 d, changes hardly with the mass loss of free evaporable water in the concrete dried at 50 °C, increases relatively by 4% when ambient temperature decreases from 15 °C to ?20 °C, and decreases relatively by 13% with temperature increasing by 88 °C. It is suggested that the electric resistance of the CFRC is stable, which is testified by the stable power output obtained by electrifying the CFRC slab with a given voltage. This implies that such kind of high content carbon fiber reinforced cement composite is potentially a desirable electrothermal material for airfield runways and road surfaces deicing.
文摘In this paper, a robust controller for electrically driven robotic systems is developed. The controller is designed in a backstepping manner. The main features of the controller are: 1) Control strategy is developed at the voltage level and can deal with both mechanical and electrical uncertainties. 2) The proposed control law removes the restriction of previous robust methods on the upper bound of system uncertainties. 3) It also benefits from global asymptotic stability in the Lyapunov sense. It is worth to mention that the proposed controller can be utilized for constrained and nonconstrained robotic systems. The effectiveness of the proposed controller is verified by simulations for a two link robot manipulator and a four-bar linkage. In addition to simulation results,experimental results on a two link serial manipulator are included to demonstrate the performance of the proposed controller in tracking a given trajectory.
基金supported by the under Grant No.51872232,the Key Scientific and Technological Innovation Research Team of Shaanxi Province(No.2022TD-31)the Key R&D Program of Shaanxi Province(No.2021ZDLGY14-04)+2 种基金the National Training Program of Innovation and Entrepreneurship for Undergraduates(Grand No.XN2022023)the Joint Funds of the National Natural Science Foundation of China(Grant No.U21B2067)the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(Grant No.136-QP-2015).
文摘The functionality of wood has evolved with time to adapt to the emerging needs of society.Carbonized wood-based composites have attracted tremendous interest in the fields of aerospace,military power,electric power,and system electronic devices,especially at high temperatures.Nevertheless,their electrical conductivity and thermal stability characteristics are still far from satisfactory.Herein,an innova-tive wood-derived carbon-carbon nanotubes-pyrolytic carbon composites(WDC-CNTs-PyCs)is successfully fabricated by chemical vapor deposition and chemical vapor infiltration.The combination of wood-derived carbon(WDC),carbon nanotubes(CNTs),and pyrolytic carbon(PyC)has never been reported in any previous work.We have innovatively introduced PyC into the WDC by chemical vapor infiltration.CNTs promote the continuous deposition of PyC to form dense structures.WDC-CNTs-PyC demonstrates significant compressive strength(85.4 MPa)and excellent electrical conductivity(632 S cm^(-1)).The weight loss rate of WDC-CNTs-PyC is 6%after heating at 500℃ for 10 min in the air atmosphere.Furthermore,WDC-CNTs-PyC could resist oxyacetylene ablation above 2300℃ for 15 s.With excellent electrical conductivity,outstanding thermal stability,and mechanical properties,WDC-CNTs-PyC opens up a surprising strategy for efficiently fabricating various high-performance electronic device composites that could be used in high-temperature fields.
基金supported by the National Natural Science Foundation of China(10972121,10732050 and 10525210)973 Program(2010CB631005)
文摘Using a recently established liquid crystal model for vesicles, we present a theoretical method to analyze the morphological stability of liquid crystal vesicles in an electric field. The coupled mechanical-electrical effects associated with elastic bending, osmotic pressure, surface tension, Max- well pressure, as well as flexoelectric and dielectric proper- ties of the membrane are taken into account. The first and second variations of the free energy are derived in a com- pact form by virtue of the surface variational principle. The former leads to the shape equation of a vesicle embedded in an electric field, and the latter allows us to examine the stabil- ity of a given vesicle morphology. As an illustrative exam- ple, we analyze the stability of a spherical vesicle under a uniform electric field. This study is helpful for understanding and revealing the morphological evolution mechanisms of vesicles in electric fields and some associated phenomena of cells.
基金Supported by the National Natural Science Foundation of China(50635040)the National High Technology Research and Development Program of China("863"Program)(2006AA04Z321)the Natural Science Foundation of Jiangsu Province(BK2008043)~~
文摘Effect of electrode insulation on the electric field and the flow field of the machining gap during electrochemical drilling（ECD） is numerically studied. Electric field simulation shows that the current density along the side gap decreases with increasing the thickness of electrode insulation. And the analysis of the electrolyte flow in the frontal gap shows that the insulation thickness has a remarkable influence on the pressure distributions. Ex- periments investigate the influence of the insulation thickness on the main characteristics of the machined hole, i.e. , radial overcut, entrance conicity, and current stability. The poor hole is observed and identified as most likely to occur with a combination of the low tool feed rate and the low insulation thickness. The appropriate thickness of the insulating layer leads to an improvement on hole accuracy and machining stability.
基金Special Funds of the National Natural Science Foundation of China on"Major New Drugs Innovation and Development"(Grant No.2014ZX09304307-002)
文摘Valtrate is the main drug quality control for the qualitative and quantitative analysis of Valerian medicines in the Chinese Pharmacopoeia 2010. However, valtrate is unstable under some conditions. We, for the first time, systemically evaluated the stability of two bath reference standards （RS） by high performance liquid chromatography coupled with a triple quadrupole mass spectrometer （HPLC-MS/MS）. The forced degradations of valtrate were performed to evaluate its optimal storage, transportation and experiment conditions according to ICH guideline. The developed HPLC method was validated to determine the degradation products. Valtrate RS was sensitive to alkaline and thermal conditions, but it was relatively stable under acidic, oxidation and photolysis conditions. A total of nine degradation components were identified under alkaline hydrolysis （N1-N4） and thermal degradation （B1-B5）. The information obtained in this work would be valuable to minimize the decomposition of valtrate during the processes of preparation, storage, distribution and utilization. It was highly suggested to store valtrate with a single dose packing in brown closed ampoule at -20℃. Under the above-mentioned storage condition, valtrate could be stable for up to 3 years.
基金Project supported by the Agricultural Development Program of the Chinese Academy of Sciences (No. KSCX1-YWN1504)the West Light Foundation of the Chinese Academy of Sciences (No. 2005404)the National Natural Science Foundation of China (Nos. 50479065 and 40601041).
文摘To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis. The experiment consisted of 17 fertilizer treatments, containing the combinations of different N and P levels, with three replications arranged in a randomized complete block design. Nitrogen fertilizer was applied as urea, and P was applied as calcium superphosphate. Fertilizer rates had a large effect on the response of wheat yield to fertilization. Phosphorus, combined with N, increased yield significantly （P 〈 0.01）. In the unfertilized control and the N or P sole application treatments, wheat yield had a declining trend although it was not statistically significant. Stability analysis combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat.
基金supported by the National Key Research and Development Program of China(2016YFD0300803)the Special Fund for Agro-scientific Research in the Public Interest(201503116-10)+1 种基金the Agricultural Science and Technology Innovation Program(CAAS-XTCX2016019-03 and Y2016XT01-03)the Science and Technology Major Project of Anhui Province(16030701099)
文摘An understanding of wheat yield and yield stability response to fertilization is important for sustainable wheat production. A 36-year long-term fertilization experiment was employed to evaluate the yield and yield stability of winter wheat. Five fertilization regimes were compared,including(1) CK, no fertilizer;(2) NPK, inorganic fertilizer only;(3) O, organic fertilizer only;(4)NPKO, 50% of NPK plus 50% of O, and(5) HNPKO, 80% of NPK plus 80% of O. The greatest yield increase was recorded in HNPKO, followed by NPKO, with O producing the lowest mean yield increase. Over the 36 years, the rate of wheat yield increase in fertilized plots ranged from95.31 kg ha-1 year-1 in the HNPKO to 138.65 kg ha-1 year-1 in the O. Yield stability analysis using the additive main effects and multiplicative interactions(AMMI) method assigned 62.3%, 26.3%,and 11.4% of sums of squares to fertilization effect, environmental effect, and fertilization ×environment interaction effect, respectively. The combination of inorganic and organic fertilization(NPKO and HNPKO) appeared to produce more stable yields than O or NPK, with lower coefficients of variation and AMMI stability value. However, wheat grown with O seemed to be the most susceptible to climate change and the least productive among the fertilized plots.Significant correlations of grain yield with soil properties and with mean air temperature were observed. These findings suggest that inorganic + organic fertilizer can increase wheat yield and its stability by improvement in soil fertility and reduction in variability to climate change.
基金the National Key Research and Development Program of China (2017YFD0301203, 2017YFD0300100, and 2018YFD0300803)Jiangsu Agriculture Science and Technology Innovation Fund (CX(18)1002)。
文摘Straw incorporation is a global common practice to improve soil fertility and rice yield.However,the effect of straw incorporation on rice yield stability is still unknown,especially under high fertilization level conditions.Here,we reported the effect of straw returning on rice yield and yield stability under high fertilization levels in the rice–wheat system over nine years.The results showed that straw incorporation did not significantly affect the average rice yield of nine years.Straw incorporation reduced the coefficient of variation of rice yield by 25.8%and increased the sustainable yield index by 8.2%.The rice yield positively correlated with mean photosynthetically active radiation (PAR) of rice growth season and the effects of straw incorporation on rice yield depended on the PAR.Straw incorporation increased the rice yield by 5.4%in the low PAR years,whereas it did not affect the rice yield in the high PAR years.Long-term straw incorporation lowered soil bulk density but improved the soil organic matter,total N,available N,available P,and available K more strongly than straw removal.Our findings suggest that straw incorporation can increase rice yield stability through improving the resistance of rice plant growth to low PAR.
基金Supported by the National Natural Science Foundation of China (30901004,30871749,31071518)the Natural Science Foundation of Fujian Province (2011J01285)+1 种基金Scientific and Technological Project of Guangdong Province (2010B080701079)Scientific and Technological Project of Guangdong scholars (10B005D)
文摘Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding interactions of KGM were reduced after being treated with high-voltage pulse electric field,but there was no significant effect on its fiber chain form and thermal characteristics.Results of the study can provide a useful reference for further study on the structure and property of KGM,and especially can provide theoretical basis for the effect of physical field on the foodstuff deep processing related to KGM.
基金supported by the National Nature Science Foundation(U1664263)National Key R&D Program of China(2016YFB0101102)。
文摘In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY23E060004)Royal Society Newton Advanced Fellowship(No.52061130218)
文摘Safe operation of electrochemical capacitors(supercapacitors)is hindered by the flammability of commercial organic electrolytes.Non-flammable Water-in-Salt(WIS)electrolytes are promising alternatives;however,they are plagued by the limited operation voltage window(typically≤2.3 V)and inherent corrosion of current collectors.Herein,a novel deep eutectic solvent(DES)-based electrolyte which uses formamide(FMD)as hydrogen-bond donor and sodium nitrate(NaNO_(3))as hydrogen-bond acceptor is demonstrated.The electrolyte exhibits the wide electrochemical stability window(3.14 V),high electrical conductivity(14.01 mScm^(-1)),good flame-retardance,anticorrosive property,and ultralow cost(7%of the commercial electrolyte and 2%of WIS).Raman spectroscopy and Density Functional Theory calculations reveal that the hydrogen bonds between the FMD molecules and NO_(3)^(-)ions are primarily responsible for the superior stability and conductivity.The developed NaNO_(3)/FMD-based coin cell supercapacitor is among the best-performing state-of-art DES and WIS devices,evidenced by the high voltage window(2.6 V),outstanding energy and power densities(22.77 Wh kg^(-1)at 630 W kg^(-1)and 17.37 kW kg^(-1)at 12.55 Wh kg^(-1)),ultralong cyclic stability(86%after 30000 cycles),and negligible current collector corrosion.The NaNO_(3)/FMD industry adoption potential is demonstrated by fabricating 100 F pouch cell supercapacitors using commercial aluminum current collectors.
基金the National Key RESEARCH and Development Program of the Ministry of Science and Technology‘Life Prediction and Operation Risk Assessment of UHV Equipment under long-term Service conditions(No.2017YFB0902705)’for supporting this workthe No.703 Research Institute of CSIC(China Shipbuilding Industry Corporation)Yunnan Electric Test&Research Institute Group CO.,Ltd for assistance in this paper.
文摘In this paper, an improved air discharge fluid model under non-uniform electric field is constructed based on the plasma module COMSOL Multiphysics with artificial stability term, and the boundary conditions developed in the previous paper are applied to the calculation of photoionization rate. Based on the modified model, the characteristics of low temperature subatmospheric air discharge under 13 kV direct current voltage are discussed, including needle-plate and needle-needle electrode structures. Firstly, in order to verify the reliability of the model, a numerical example and an experimental verification were carried out for the modified model respectively. Both verification results show that the model can ensure the accuracy and repeatability of the calculation. Secondly, according to the calculation results of the modified model, under the same voltage and spacing, the reduced electric field under low temperature subatmosphere pressure is larger than that under normal temperature and atmospheric pressure. The high electric field leads to the air discharge at low temperature and sub atmospheric pressure entering the streamer initiation stage earlier, and has a faster propagation speed in the streamer development stage, which shortens the overall discharge time. Finally, the discharge characteristics of the two electrode structures are compared, and it is found that the biggest difference between them is that there is a pre-ionization region near the cathode in the needle-needle electrode structure. When the pre-ionization level reaches 1013 cm-3, the propagation speed of the positive streamer remains unchanged throughout the discharge process, and is no longer affected by the negative streamer. The peak value of electric field decreases with the increase of pre-ionization level, and tends to be constant during streamer propagation. Based on the previous paper, this paper constructs the air discharge model under non-uniform electric field, complements with the previous paper, and forms a relatively complete set of air discharge simulation system under low temperature and sub atmospheric pressure, which provides a certain reference for future research.
基金supported by the National Key Research and Development Program of China(2018YFA0208701)the National Natural Science Foundation of China(21773308)+7 种基金the Research Funds of Renmin University of China(2017030013,201903020 and 20XNH059)the Fundamental Research Funds for Central Universities(China)supported by the Solar Energy Research Institute of Singapore(SERIS) at the National University of Singapore(NUS)supported by NUSthe National Research Foundation Singapore(NRF)the Energy Market Authority of Singapore(EMA)the Singapore Economic Development Board(EDB)the financial support from the China Scholarship Council(CSC) funding。
文摘The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphipathic molecule Triton X100(Triton) is modified on the NiO_(x)surface.The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiO_(x)surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiO_(x)/perovskite interface.Additionally,the hydrophobic chain of Triton protrudes from the NiO_(x)surface to prevent moisture from penetrating into the NiO_(x)/perovskite interface.Consequently,the NiO_(x)/Triton-based devices(MAPbI3as absorbing layer) show superior moisture and thermal stability,retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air(40%-50% relative humidity(RH)) at 25 ℃ for 1070 h and in N2at 85℃ for 800 h,respectively.Moreover,the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction capability.Besides,the NiO_(x)/Triton-based PSCs with Cs_(0.05)(MA_(0.15)FA_(0.85))_(0.95)Pb(I_(0.85)Br_(0.15))3perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices,indicating the viability of our strategies.Of particular note,a champion PCE of 22.35% and 20.46% was achieved for small-area(0.1 cm^(2)) and large-area(1.2 cm^(2)) NiO_(x)/Triton-based devices,respectively.
