The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.B...The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.Based on the requirements of the hybrid vehicle and the characteristic of Atkinson cycle,a set of designing methods for the Atkinson cycle gasoline engine is presented through the analysis of the optimized matching for the compression ratio,valve timing and the combustion chamber.The designing method has been verified by the bench test and the results show that the fuel consumption can be improved by12%–15%with the reduction of the low speed torque by 10%,and the low fuel consumption region in the fuel map extends significantly with the rated power almost keeping constant.It may be of great reference for the development of hybrid vehicle technology in China.展开更多
The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies ...The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies of MnO_(2)@C materials can be controlled by controlling the dosages of WS-CTPs and KMnO4.Meanwhile,it is aware that MnO_(2)exists in the MnO_(2)@C materials in an amorphous state.Compared with MnO_(2),MnO_(2)@C materials output a remarkable improvement in electrochemical performance.For instance,MnO_(2)@C-0.3 shows the storage capacity at 965.7 mA h g^(−1)after 300 cycles at a current density of 0.1 A g^(−1).In addition,after 600 cycles at a current density of 1.0 A g^(−1),the storage capacity of MnO_(2)@C-0.3 still keeps 450.3 mA h g^(−1),indicating that MnO_(2)@C-0.3 owns tremendous cycle stability at a high current density.In view of the fact that the coal tar pitches possess great cost advantages,the strategy of using WS-CTPs as a carbon source to cover the metal oxides is a competitive way to expand the application of metal oxides in the fabrication of electrodes of LIBs.展开更多
Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature condit...Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions(below0°C and above 50 °C).Here,we report the design of F/Mo co-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(FMNCM)cathode for high-performance LIBs from-20 to 60°C.F^(-) doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer.Concurrently,the Mo^(6+) doping suppresses phase transition,which blocks Li^(+)/Ni^(2+) mixing,and stabilizes lithium-ion diffusion pathway.Remarkably,the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V,even at 60°C,maintaining 90.6%capacity retention at 3 C after 150 cycles.Additionally,at temperatures as low as-20°C,it retains 77.1%of its room temperature capacity,achieving an impressive 97.5%capacity retention after 500 cycles.Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells.This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs,presenting a promising path towards high-energy and long-cycling LIBs with temperatureadaptability.展开更多
A study was conducted to evaluate the effects of meat and bone meal （MBM） and poultry by-product meal （PBM） as the replacement of fishmeal in the diets on the growth performance, survival and apparent digestibilit...A study was conducted to evaluate the effects of meat and bone meal （MBM） and poultry by-product meal （PBM） as the replacement of fishmeal in the diets on the growth performance, survival and apparent digestibility coefficient （ADC） of Japanese flounder （Paralichthys olivaceus）. The experimental diets included 0%, 20%, 40%, 60% and 80% MBM or PBM replacement of total fishmeal respectively. All diets were iso-nitrogenous and isocaloric. The results showed that there are no significant differences （P 〉0.05） in growth performance among the treatments fed with 0% -60% MBM replacement of fishmeal, while the percent weight gain （WG, % ）, body length gain （BLG, % ） and ADC significantly decrease when fishmeal is replaced by 80% MBM. The result showed also that there are no significant differences （P 〉0.05） in growth performance and ADC among all treatments fed with the diets with 0% -80% replacements of fishmeal with PBM.展开更多
Modeling of unsteady aerodynamic loads at high angles of attack using a small amount of experimental or simulation data to construct predictive models for unknown states can greatly improve the efficiency of aircraft ...Modeling of unsteady aerodynamic loads at high angles of attack using a small amount of experimental or simulation data to construct predictive models for unknown states can greatly improve the efficiency of aircraft unsteady aerodynamic design and flight dynamics analysis.In this paper,aiming at the problems of poor generalization of traditional aerodynamic models and intelligent models,an intelligent aerodynamic modeling method based on gated neural units is proposed.The time memory characteristics of the gated neural unit is fully utilized,thus the nonlinear flow field characterization ability of the learning and training process is enhanced,and the generalization ability of the whole prediction model is improved.The prediction and verification of the model are carried out under the maneuvering flight condition of NACA0015 airfoil.The results show that the model has good adaptability.In the interpolation prediction,the maximum prediction error of the lift and drag coefficients and the moment coefficient does not exceed 10%,which can basically represent the variation characteristics of the entire flow field.In the construction of extrapolation models,the training model based on the strong nonlinear data has good accuracy for weak nonlinear prediction.Furthermore,the error is larger,even exceeding 20%,which indicates that the extrapolation and generalization capabilities need to be further optimized by integrating physical models.Compared with the conventional state space equation model,the proposed method can improve the extrapolation accuracy and efficiency by 78%and 60%,respectively,which demonstrates the applied potential of this method in aerodynamic modeling.展开更多
Trajectory analysis of fuel injection into supersonic cross flow is studied in this paper. A directly-connected wind tunnel is constructed to provide stable supersonic freestream. Based on the test rig, the schlieren ...Trajectory analysis of fuel injection into supersonic cross flow is studied in this paper. A directly-connected wind tunnel is constructed to provide stable supersonic freestream. Based on the test rig, the schlieren system is established to reveal the fuel injection process visually. Subsequently, the method of quantitative schlieren is adopted to obtain data of both fuel/air interface and bow shock with the aid of Photoshop and Origin. Finally, the mechanism based on two influential factors of fuel injection angle and fuel injection driven pressure, is researched by vector analysis. A dimensionless model is deduced and analyzed. The curve fitting result is achieved. The relationship between the data and the two influential factors is established. The results provide not only the quantitative characteristics of the fuel injection in supersonic cross flow but also the valuable reference for the future computational simulation.展开更多
Smart textiles are able to self-adapt to an irregular surface.So,they found new applications in intelligent clothes and equipments,where the properties and functionality of traditional polymeric fibers are insufficien...Smart textiles are able to self-adapt to an irregular surface.So,they found new applications in intelligent clothes and equipments,where the properties and functionality of traditional polymeric fibers are insufficient,and hard to be realized.Inspired by the supercontraction behavior of the spider silk,we prepared a spinnable hydrogel to form a sheath-core-like composite yarn,after being coated on cotton yarn.The strong hydrogen bonding between the cotton yarn and the polar groups of the hydrogel provides an outstanding mechanical stability,and the twists insertion forms a spiral-like architecture,which exhibited moisture-responsive super contraction behavior.By structural tailoring the chirality of the fiber twists and coiling extends into homo-chiral and heterochiral architectures,as displays contraction and expansion when is exposed to the moisture.Once the relative humidity is increased from 60 to 90%,a homochiral yarn exhibits 90%contraction,while a heterochiral yarn shows 450% expansion,and the maximum work capacity reached up to 6.1 J/Kg.The super contracted yarn can be re-stretched to its original length manifesting cyclability,which can be exploited to build a smart textile,selfadaptive to irregular surfaces.Such a strategy may be further extended to a wide variety of materials to achieve intelligent textiles from common fiber or yarns.展开更多
Membrane separation has become an important technology to deal with the global water crisis. The polymerbased membrane technology is currently in the forefront of water purification and desalination but is plagued wit...Membrane separation has become an important technology to deal with the global water crisis. The polymerbased membrane technology is currently in the forefront of water purification and desalination but is plagued with some bottlenecks. Laminated graphene oxide(GO) membranes exhibit excellent advantages in water purification and desalination due to the single atomic layer structure, hydrophilic property, rich oxygen-containing groups for modification, mechanical and chemical robust, anti-fouling properties, facile and large-scale production, etc. Thus the GO-based membrane technology is believed to offer huge opportunities for efficient and practical water treatment. This review systematically summarizes the current progress on the water flux and selectivity intensification, stability improvement, anti-fouling and anti-biofouling ability enhancement by structural control and modification. To improve the performance of the laminated GO membrane, interlayer spacing tunability and surface modification are mainly used to enhance its water flux and selectivity. It is found that the stability and biofouling also block the service life of the GO membrane. The crosslinking method is found to effectively solve the stability of GO membrane in aqueous environment. Introducing nanoparticles is a widely used method to improve the membrane biofouling ability. Overall, we believe that this review could provide benefit to researchers in the area of GO-based membrane technology for water treatment.展开更多
Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unsta...Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unstable solid-electrolyte interface,which hampers the practical application of Si anode.Herein,a Si-based anode with a hierarchical pomegranate-structure(HPS-Si)was designed to modulate the stress variation,and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO_(2-x),SiC,and carbon.The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials.Meanwhile,the reasonable pore structure from SiO_(2) reduction owing to density difference is enough to accommodate the limited volume expansion.The Si spheres with a size of about 50 nm can prevent self-cracking.SiO_(2-x),and SiC as flexible and rigid layers,have been syner-gistically used to reduce the surface stress of conductive carbon layers to avoid cracking.The covalent bonding immensely strengthens the link of the modification with Si nanospheres,thus resisting stress effects.Consequently,a full cell comprising an HPS-Si anode and a LiCoO_(2) cathode achieved an energy density of 415 Wh kg^(-1) with a capacity retention ratio of 87.9%after 300 cycles based on the active ma-terials.It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode.展开更多
Both nitrogen-doping feature and pore structure are critical factors for developing nitrogen-doped carbons based catalysts with a high performance toward oxygen reduction reaction(ORR).Herein,a simple one-step CVD of ...Both nitrogen-doping feature and pore structure are critical factors for developing nitrogen-doped carbons based catalysts with a high performance toward oxygen reduction reaction(ORR).Herein,a simple one-step CVD of acetylene and acetonitrile vapor method using silanized SBA-15 as a template has been developed to synthesize an ordered porous carbon(OPC) with dual nitrogen-doped interfaces.The optimized sample as prepared with the CVD of 4 h at 750℃ contains two types of ordered mesopores that one type is the ordered cylindrical pores inheriting from the pores of SBA-15 and has a pore width of4.0~5.0 nm,the other type is the ordered quasi-hexagonal pores with a width of 3.0~4.0 nm produced by etching the pore walls of SBA-15.These two types of pores whose pore walls are built by the nitrogen doped carbon layers resulted by the CVD and thus it actually makes the dual nitrogen-doped interfaced OPC(DN-OPC).Meanwhile,DN-OPC contains a few of micropores and a large SSA of 1430 m~2/g.This dualordered pores and dual nitrogen-doped interfaces cannot only facilitate mass transport but also utilize the active sites of DN-OPC for ORR.Therefore,as metal-free ORR catalyst,DN-OPC exhibits a good activity close to commercial Pt/C catalyst,and an excellent durability and methanol tolerance.展开更多
This paper investigates the problem of parameter identification for ship nonlinear Nomoto model with small test data,a nonlinear innovation-based identification algorithm is presented by embedding sigmoid function in ...This paper investigates the problem of parameter identification for ship nonlinear Nomoto model with small test data,a nonlinear innovation-based identification algorithm is presented by embedding sigmoid function in the stochastic gradient algorithm.To demonstrate the validity of the algorithm,an identification test is carried out on the ship‘SWAN’with only 26 sets of test data.Furthermore,the identification effects of the least squares algorithm,original stochastic gradient algorithm and the improved stochastic gradient algorithm based on nonlinear innovation are compared.Generally,the stochastic gradient algorithm is not suitable for the condition of small test data.The simulation results indicate that the improved stochastic gradient algorithm with sigmoid function greatly increases its accuracy of parameter identification and has 14.2%up compared with the least squares algorithm.Then the effectiveness of the algorithm is verified by another identification test on the ship‘Galaxy’,the accuracy of parameter identification can reach more than 95%which can be used in ship motion simulation and controller design.The proposed algorithm has advantages of the small test data,fast speed and high accuracy of identification,which can be extended to other parameter identification systems with less sample data.展开更多
This paper is devoted to experimentally investigating the influence of magnetic field intensity and gas temperature on the plasma jet deflection controlled by magneto hydrodynamics. The catalytic ionization seed CS_2C...This paper is devoted to experimentally investigating the influence of magnetic field intensity and gas temperature on the plasma jet deflection controlled by magneto hydrodynamics. The catalytic ionization seed CS_2CO_3 is injected into combustion gas by artificial forced ionization to obtain plasma fluid on a high-temperature magnetic fluid experimental platform. The plasma jet was deflected under the effect of an external magnetic field, forming a thrust-vector effect.Magnesium oxide was selected as a tracer particle, and a two-dimensional image of the jet flow field was collected using the particle image velocimetry(PIV) measurement method. Through image processing and velocity vector analysis of the flow field, the value of the jet deflection angle was obtained quantitatively to evaluate the thrust-vector effect. The variation of the jet deflection angle with the magnetic field intensity and gas temperature was studied under different experimental conditions. Experimental results show that the jet deflection angle increased gradually with a rise in gas temperature and then increased substantially when the gas temperature exceeded 2300 K. The jet deflection angle also increased with an increase in magnetic induction intensity. Experiments demonstrate it is feasible to use PIV test technology to study the thrust vector under magnetic control conditions.展开更多
Under the condition of simulated rain precipitation in the laboratory, with EIS and SEM observation, the effects of pH value of simulated rain on corrosion and runoff behavior of carbon steel A3 were studied. The corr...Under the condition of simulated rain precipitation in the laboratory, with EIS and SEM observation, the effects of pH value of simulated rain on corrosion and runoff behavior of carbon steel A3 were studied. The corrosion rate of A3 steel increased and runoff action of rain precipitation on A3 steel surface was intensified with decreasing pH value, of simulated rainwater. The runoff and corrosion traces were formed along the flowing direction of rainwater, which appeared more apparently with decreasing pH value.展开更多
In this research, the toxic effects of deltamethrin （DM） on the behavior responses of Zebra fish （Damo rerio） in the characteristic of behavior strength were investigated followed by an assessment of an in situ re...In this research, the toxic effects of deltamethrin （DM） on the behavior responses of Zebra fish （Damo rerio） in the characteristic of behavior strength were investigated followed by an assessment of an in situ remediation of the DM pollution using sodium percarbonate. Behavior strength ofDanio rerio was approximately 0.83 in the control group and was slightly higher than 0.83 in the sublethal treatment （0.1 TU （toxic unit））, which suggested that sublethal DM exposure could induce a stimulation effect in 48 h of exposure. In lower DM concentration treatments （0.5 and 1.0 TU）, behavior strength could be inhibited significantly. Behavior responses of Danio rerio showed a gradually increased tendency when they were exposed to higher concentration of DM, and the declining amplitudes of behavior strength changed with the increase of DM concentrations. These results suggested that DM had evident acute toxicity effects on the behavior responses of Danio rerio with a good dose-effect relationship. The in situ remediation of the DM pollution using sodium percarhonate showed that the toxic effect of DM on behavior responses ofDanio rerio could be eliminated even in the highest concentration of DM （5.0 TU）. Meanwhile, the behavior response of Danio rerio in the treatment of sodium percarbonate was the same as in the control, which indicated that sodium percarbonate had no evident toxic effects on the behavior of Daniu rerio in the current concentration. This study suggested that adding sodium percarbonate in situ might be a good way to eliminate the DM toxic effects.展开更多
Destruction of 4-phenolsulfonic acid （4-PSA） in water was carded out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon （TOC） in water correspondi...Destruction of 4-phenolsulfonic acid （4-PSA） in water was carded out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon （TOC） in water correspondingly decreased, while the sulfonate group of 4- PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH.展开更多
文摘The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.Based on the requirements of the hybrid vehicle and the characteristic of Atkinson cycle,a set of designing methods for the Atkinson cycle gasoline engine is presented through the analysis of the optimized matching for the compression ratio,valve timing and the combustion chamber.The designing method has been verified by the bench test and the results show that the fuel consumption can be improved by12%–15%with the reduction of the low speed torque by 10%,and the low fuel consumption region in the fuel map extends significantly with the rated power almost keeping constant.It may be of great reference for the development of hybrid vehicle technology in China.
基金This work was supported by the University of Science and Technology Liaoning(Grant Nos.601009816-39 and 2017RC03)the Liaoning Province Education Department of China(Grant Nos.601009887-16 and LJKQZ2021126)+1 种基金the National Natural Science Foundation of China(Grant Nos.51672117 and 51672118)the Postdoctoral Foundation Project of Shenzhen Polytechnic(Grant No.6020330007K).
文摘The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies of MnO_(2)@C materials can be controlled by controlling the dosages of WS-CTPs and KMnO4.Meanwhile,it is aware that MnO_(2)exists in the MnO_(2)@C materials in an amorphous state.Compared with MnO_(2),MnO_(2)@C materials output a remarkable improvement in electrochemical performance.For instance,MnO_(2)@C-0.3 shows the storage capacity at 965.7 mA h g^(−1)after 300 cycles at a current density of 0.1 A g^(−1).In addition,after 600 cycles at a current density of 1.0 A g^(−1),the storage capacity of MnO_(2)@C-0.3 still keeps 450.3 mA h g^(−1),indicating that MnO_(2)@C-0.3 owns tremendous cycle stability at a high current density.In view of the fact that the coal tar pitches possess great cost advantages,the strategy of using WS-CTPs as a carbon source to cover the metal oxides is a competitive way to expand the application of metal oxides in the fabrication of electrodes of LIBs.
基金the financial support from the National Natural Science Foundation of China(51972156,52072378,52102054 and 51927803)the National Key R&D Program of China(2022YFB3803400,2021YFB3800301)+2 种基金the Shenyang Science and Technology Program(22-322-3-19)the Youth Fund of the Education Department of Liaoning Province(LJKQZ20222324)the Outstanding Youth Fund of University of Science and Technology Liaoning(2023YQ11).
文摘Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries(LIBs)but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions(below0°C and above 50 °C).Here,we report the design of F/Mo co-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(FMNCM)cathode for high-performance LIBs from-20 to 60°C.F^(-) doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer.Concurrently,the Mo^(6+) doping suppresses phase transition,which blocks Li^(+)/Ni^(2+) mixing,and stabilizes lithium-ion diffusion pathway.Remarkably,the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V,even at 60°C,maintaining 90.6%capacity retention at 3 C after 150 cycles.Additionally,at temperatures as low as-20°C,it retains 77.1%of its room temperature capacity,achieving an impressive 97.5%capacity retention after 500 cycles.Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells.This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs,presenting a promising path towards high-energy and long-cycling LIBs with temperatureadaptability.
文摘A study was conducted to evaluate the effects of meat and bone meal （MBM） and poultry by-product meal （PBM） as the replacement of fishmeal in the diets on the growth performance, survival and apparent digestibility coefficient （ADC） of Japanese flounder （Paralichthys olivaceus）. The experimental diets included 0%, 20%, 40%, 60% and 80% MBM or PBM replacement of total fishmeal respectively. All diets were iso-nitrogenous and isocaloric. The results showed that there are no significant differences （P 〉0.05） in growth performance among the treatments fed with 0% -60% MBM replacement of fishmeal, while the percent weight gain （WG, % ）, body length gain （BLG, % ） and ADC significantly decrease when fishmeal is replaced by 80% MBM. The result showed also that there are no significant differences （P 〉0.05） in growth performance and ADC among all treatments fed with the diets with 0% -80% replacements of fishmeal with PBM.
基金supported in part by the National Natural Science Foundation of China (No. 12202363)。
文摘Modeling of unsteady aerodynamic loads at high angles of attack using a small amount of experimental or simulation data to construct predictive models for unknown states can greatly improve the efficiency of aircraft unsteady aerodynamic design and flight dynamics analysis.In this paper,aiming at the problems of poor generalization of traditional aerodynamic models and intelligent models,an intelligent aerodynamic modeling method based on gated neural units is proposed.The time memory characteristics of the gated neural unit is fully utilized,thus the nonlinear flow field characterization ability of the learning and training process is enhanced,and the generalization ability of the whole prediction model is improved.The prediction and verification of the model are carried out under the maneuvering flight condition of NACA0015 airfoil.The results show that the model has good adaptability.In the interpolation prediction,the maximum prediction error of the lift and drag coefficients and the moment coefficient does not exceed 10%,which can basically represent the variation characteristics of the entire flow field.In the construction of extrapolation models,the training model based on the strong nonlinear data has good accuracy for weak nonlinear prediction.Furthermore,the error is larger,even exceeding 20%,which indicates that the extrapolation and generalization capabilities need to be further optimized by integrating physical models.Compared with the conventional state space equation model,the proposed method can improve the extrapolation accuracy and efficiency by 78%and 60%,respectively,which demonstrates the applied potential of this method in aerodynamic modeling.
文摘Trajectory analysis of fuel injection into supersonic cross flow is studied in this paper. A directly-connected wind tunnel is constructed to provide stable supersonic freestream. Based on the test rig, the schlieren system is established to reveal the fuel injection process visually. Subsequently, the method of quantitative schlieren is adopted to obtain data of both fuel/air interface and bow shock with the aid of Photoshop and Origin. Finally, the mechanism based on two influential factors of fuel injection angle and fuel injection driven pressure, is researched by vector analysis. A dimensionless model is deduced and analyzed. The curve fitting result is achieved. The relationship between the data and the two influential factors is established. The results provide not only the quantitative characteristics of the fuel injection in supersonic cross flow but also the valuable reference for the future computational simulation.
基金This work was supported by the National Key Research and Development Program of China(Grant#2019YFE0119600)the National Natural Science Foundation of China(Grants 51973093,U1533122,and 51773094)+5 种基金“Frontiers Science Center for New Organic Matter”,Nankai University,Tianjin,China(Grant#63181206)the Science Foundation for Distinguished Young Scholars of Tianjin(Grant#18JCJQJC46600)the Xingliao Talent Plan(XLYC1802042)Key Laboratory of Display Materials and Photoelectric Devices,Ministry of Education(LX20200420001)the Fundamental Research Funds for the Central Universities(Grant#63171219)National Special Support Plan for High-level Talents people(C041800902).
文摘Smart textiles are able to self-adapt to an irregular surface.So,they found new applications in intelligent clothes and equipments,where the properties and functionality of traditional polymeric fibers are insufficient,and hard to be realized.Inspired by the supercontraction behavior of the spider silk,we prepared a spinnable hydrogel to form a sheath-core-like composite yarn,after being coated on cotton yarn.The strong hydrogen bonding between the cotton yarn and the polar groups of the hydrogel provides an outstanding mechanical stability,and the twists insertion forms a spiral-like architecture,which exhibited moisture-responsive super contraction behavior.By structural tailoring the chirality of the fiber twists and coiling extends into homo-chiral and heterochiral architectures,as displays contraction and expansion when is exposed to the moisture.Once the relative humidity is increased from 60 to 90%,a homochiral yarn exhibits 90%contraction,while a heterochiral yarn shows 450% expansion,and the maximum work capacity reached up to 6.1 J/Kg.The super contracted yarn can be re-stretched to its original length manifesting cyclability,which can be exploited to build a smart textile,selfadaptive to irregular surfaces.Such a strategy may be further extended to a wide variety of materials to achieve intelligent textiles from common fiber or yarns.
基金Supported by the National Natural Science Foundation of China(Grant Nos.21506019,51672118,51672117)the Fundamental Research Funds for the Central Universities(Grant Nos.DUT16RC(4)80,DUT16QY43)the Program for Changjiang Scholars(T2012049)
文摘Membrane separation has become an important technology to deal with the global water crisis. The polymerbased membrane technology is currently in the forefront of water purification and desalination but is plagued with some bottlenecks. Laminated graphene oxide(GO) membranes exhibit excellent advantages in water purification and desalination due to the single atomic layer structure, hydrophilic property, rich oxygen-containing groups for modification, mechanical and chemical robust, anti-fouling properties, facile and large-scale production, etc. Thus the GO-based membrane technology is believed to offer huge opportunities for efficient and practical water treatment. This review systematically summarizes the current progress on the water flux and selectivity intensification, stability improvement, anti-fouling and anti-biofouling ability enhancement by structural control and modification. To improve the performance of the laminated GO membrane, interlayer spacing tunability and surface modification are mainly used to enhance its water flux and selectivity. It is found that the stability and biofouling also block the service life of the GO membrane. The crosslinking method is found to effectively solve the stability of GO membrane in aqueous environment. Introducing nanoparticles is a widely used method to improve the membrane biofouling ability. Overall, we believe that this review could provide benefit to researchers in the area of GO-based membrane technology for water treatment.
基金support by the NSFC Nos.51972156,51872131,51672117,51672118,22209055CPSF No.2022M721330Distin-guished Professor of Liaoning Province(2017)are acknowledged.
文摘Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unstable solid-electrolyte interface,which hampers the practical application of Si anode.Herein,a Si-based anode with a hierarchical pomegranate-structure(HPS-Si)was designed to modulate the stress variation,and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO_(2-x),SiC,and carbon.The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials.Meanwhile,the reasonable pore structure from SiO_(2) reduction owing to density difference is enough to accommodate the limited volume expansion.The Si spheres with a size of about 50 nm can prevent self-cracking.SiO_(2-x),and SiC as flexible and rigid layers,have been syner-gistically used to reduce the surface stress of conductive carbon layers to avoid cracking.The covalent bonding immensely strengthens the link of the modification with Si nanospheres,thus resisting stress effects.Consequently,a full cell comprising an HPS-Si anode and a LiCoO_(2) cathode achieved an energy density of 415 Wh kg^(-1) with a capacity retention ratio of 87.9%after 300 cycles based on the active ma-terials.It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode.
基金The financial supports from National Natural Science Foundation of China projects(NSFC,Nos.51672117,51672118,51872131,51972156 and 21701077)the Distinguished Professor Project of Education Department of Liaoning and Key Scientific Research Plan of Liaoning Province(No.2018304017)are acknowledged。
文摘Both nitrogen-doping feature and pore structure are critical factors for developing nitrogen-doped carbons based catalysts with a high performance toward oxygen reduction reaction(ORR).Herein,a simple one-step CVD of acetylene and acetonitrile vapor method using silanized SBA-15 as a template has been developed to synthesize an ordered porous carbon(OPC) with dual nitrogen-doped interfaces.The optimized sample as prepared with the CVD of 4 h at 750℃ contains two types of ordered mesopores that one type is the ordered cylindrical pores inheriting from the pores of SBA-15 and has a pore width of4.0~5.0 nm,the other type is the ordered quasi-hexagonal pores with a width of 3.0~4.0 nm produced by etching the pore walls of SBA-15.These two types of pores whose pore walls are built by the nitrogen doped carbon layers resulted by the CVD and thus it actually makes the dual nitrogen-doped interfaced OPC(DN-OPC).Meanwhile,DN-OPC contains a few of micropores and a large SSA of 1430 m~2/g.This dualordered pores and dual nitrogen-doped interfaces cannot only facilitate mass transport but also utilize the active sites of DN-OPC for ORR.Therefore,as metal-free ORR catalyst,DN-OPC exhibits a good activity close to commercial Pt/C catalyst,and an excellent durability and methanol tolerance.
基金funded by the National Natural Science Foundation of China,grant number 51679024,51909018the Science and Technology Innovation Fundation of Dalian City,grant number 2019J12GX026+1 种基金the Fundamental Research Funds for the Central University,grant number 3132019343,3132021132the University 111 Project of China,grant number B08046.
文摘This paper investigates the problem of parameter identification for ship nonlinear Nomoto model with small test data,a nonlinear innovation-based identification algorithm is presented by embedding sigmoid function in the stochastic gradient algorithm.To demonstrate the validity of the algorithm,an identification test is carried out on the ship‘SWAN’with only 26 sets of test data.Furthermore,the identification effects of the least squares algorithm,original stochastic gradient algorithm and the improved stochastic gradient algorithm based on nonlinear innovation are compared.Generally,the stochastic gradient algorithm is not suitable for the condition of small test data.The simulation results indicate that the improved stochastic gradient algorithm with sigmoid function greatly increases its accuracy of parameter identification and has 14.2%up compared with the least squares algorithm.Then the effectiveness of the algorithm is verified by another identification test on the ship‘Galaxy’,the accuracy of parameter identification can reach more than 95%which can be used in ship motion simulation and controller design.The proposed algorithm has advantages of the small test data,fast speed and high accuracy of identification,which can be extended to other parameter identification systems with less sample data.
基金supported by National Natural Science Foundation of China (No. 90716025)
文摘This paper is devoted to experimentally investigating the influence of magnetic field intensity and gas temperature on the plasma jet deflection controlled by magneto hydrodynamics. The catalytic ionization seed CS_2CO_3 is injected into combustion gas by artificial forced ionization to obtain plasma fluid on a high-temperature magnetic fluid experimental platform. The plasma jet was deflected under the effect of an external magnetic field, forming a thrust-vector effect.Magnesium oxide was selected as a tracer particle, and a two-dimensional image of the jet flow field was collected using the particle image velocimetry(PIV) measurement method. Through image processing and velocity vector analysis of the flow field, the value of the jet deflection angle was obtained quantitatively to evaluate the thrust-vector effect. The variation of the jet deflection angle with the magnetic field intensity and gas temperature was studied under different experimental conditions. Experimental results show that the jet deflection angle increased gradually with a rise in gas temperature and then increased substantially when the gas temperature exceeded 2300 K. The jet deflection angle also increased with an increase in magnetic induction intensity. Experiments demonstrate it is feasible to use PIV test technology to study the thrust vector under magnetic control conditions.
基金The work was supported by the National Natural Science Foundation of China(No.50101011)the Special Foundation of National Key Basic Research of China(No.1999065004).
文摘Under the condition of simulated rain precipitation in the laboratory, with EIS and SEM observation, the effects of pH value of simulated rain on corrosion and runoff behavior of carbon steel A3 were studied. The corrosion rate of A3 steel increased and runoff action of rain precipitation on A3 steel surface was intensified with decreasing pH value, of simulated rainwater. The runoff and corrosion traces were formed along the flowing direction of rainwater, which appeared more apparently with decreasing pH value.
文摘In this research, the toxic effects of deltamethrin （DM） on the behavior responses of Zebra fish （Damo rerio） in the characteristic of behavior strength were investigated followed by an assessment of an in situ remediation of the DM pollution using sodium percarbonate. Behavior strength ofDanio rerio was approximately 0.83 in the control group and was slightly higher than 0.83 in the sublethal treatment （0.1 TU （toxic unit））, which suggested that sublethal DM exposure could induce a stimulation effect in 48 h of exposure. In lower DM concentration treatments （0.5 and 1.0 TU）, behavior strength could be inhibited significantly. Behavior responses of Danio rerio showed a gradually increased tendency when they were exposed to higher concentration of DM, and the declining amplitudes of behavior strength changed with the increase of DM concentrations. These results suggested that DM had evident acute toxicity effects on the behavior responses of Danio rerio with a good dose-effect relationship. The in situ remediation of the DM pollution using sodium percarhonate showed that the toxic effect of DM on behavior responses ofDanio rerio could be eliminated even in the highest concentration of DM （5.0 TU）. Meanwhile, the behavior response of Danio rerio in the treatment of sodium percarbonate was the same as in the control, which indicated that sodium percarbonate had no evident toxic effects on the behavior of Daniu rerio in the current concentration. This study suggested that adding sodium percarbonate in situ might be a good way to eliminate the DM toxic effects.
基金supported by the 'Youth Science Foundation of University of Science and Technology Liaoning', 2012-2014
文摘Destruction of 4-phenolsulfonic acid （4-PSA） in water was carded out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon （TOC） in water correspondingly decreased, while the sulfonate group of 4- PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH.
