Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challengi...Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.展开更多
In the context of the new period,the continuous growth of social and economic levels and the rapid update of information technology have significantly impacted the business management of Chinese enterprises,presenting...In the context of the new period,the continuous growth of social and economic levels and the rapid update of information technology have significantly impacted the business management of Chinese enterprises,presenting substantial challenges.The intensification of market competition exerts development pressure on many enterprises,and coupled with the unstable strength of some businesses,numerous problems in business management arise.These issues hinder the smooth execution of various business activities.Therefore,it is crucial to ensure effective business administration to conduct different business activities in an orderly manner,promptly avoid adverse risks,and strengthen control over multiple factors.The innovation and improvement of business administration are of great significance for enhancing the management level and market competitiveness of modern enterprises,accelerating their healthy development,and creating numerous opportunities.Consequently,this paper analyzes and explores the development trends of enterprise business administration and the innovation of management models for reference.展开更多
The physical features exhibited by Hermite-Gaussian （HC） beams propagating in nonlocal nonlinear media with Gaussian-shaped response are discussed with an approximate variational method.Using direct numerical simula...The physical features exhibited by Hermite-Gaussian （HC） beams propagating in nonlocal nonlinear media with Gaussian-shaped response are discussed with an approximate variational method.Using direct numerical simulations,we find that the beam properties in the normalized system are different with the change of the degree of nonlocality.It is shown that initial HG profiles break up into several individual beams with propagation when the degree of nonlocality α is small.HG beams can propagate stably when a is large enough.展开更多
The effects of ZnO-B2O3 （ZB2） on the sintering behavior and microwave dielectric properties of （Ca0.254Li0.19Sm0.14）TiO3 ceramics were investigated. The densities of the specimens reached the maximum value by addi...The effects of ZnO-B2O3 （ZB2） on the sintering behavior and microwave dielectric properties of （Ca0.254Li0.19Sm0.14）TiO3 ceramics were investigated. The densities of the specimens reached the maximum value by adding 3 wt.% ZB2 and then decreased. The sintering temperature of the specimens was lowered from 1300 to 1100℃ without degradation of the microwave dielectric properties. The （Ca0.254Li0.19Sm0.14）TiO3＋ 3 wt.% ZB2 sintered at 1100℃ for 3 h showed good microwave dielectric properties, εr= 108.2, Qf= 6545 GHz, and rf= 6.5 ppm/℃, respectively, indicating that ZB2 was an effective sintering aid to improve the densification and microwave dielectric properties of （Ca0.254Li0.19Sm0.14）TiO3 ceramics.展开更多
Modal analysis and seismic response analysis were carried out for the equatorial diagnostic port plug of international thermonuclear experimental reactor (ITER). The aim of the theoretical analysis is to verify struct...Modal analysis and seismic response analysis were carried out for the equatorial diagnostic port plug of international thermonuclear experimental reactor (ITER). The aim of the theoretical analysis is to verify structural strength and reliability of the device. The working condition includes one-dimensional seismic wave and two-dimensional seismic wave. Modal analysis of the device shows that primary vibration is inclined to occur in low-order modes. The horizontal (X-direction, Y-direction) maximum vibration appears at the first and the fourth eigen modes, with the natural frequency of 70.59 and 215.88 Hz respectively, and the vertical (Z-direction) primary vibration appears at the second eigen mode with the natural frequency of 82.85 Hz. According to the results of the finite element analysis (FEA) program, the weak portions of the device are distributed in the joint of port body with blanket shielding module (BSM) and inner side wall of ribbed plate for lifting flange, the maximum von Mises stress is 14.8 MPa with the Y-direction seismic wave. In accordance with the design criteria, the destructive effect is far below the failure boundary, and the structural reliability of the equatorial diagnostic port plug can meet the requirements of the design specifications.展开更多
Multi-joint manipulator systems are subject to nonlinear influences such as frictional characteristics,random disturbances and load variations.To account for uncertain disturbances in the operation of manipulators,we ...Multi-joint manipulator systems are subject to nonlinear influences such as frictional characteristics,random disturbances and load variations.To account for uncertain disturbances in the operation of manipulators,we propose an adaptive manipulator control method based on a multi-joint fuzzy system,in which the upper bound information of the fuzzy system is constant and the state variables of the manipulator control system are measurable.The control algorithm of the system is a MIMO(multi-input-multi-output)fuzzy system that can approximate system error by using a robust adaptive control law to eliminate the shadow caused by approximation error.It can ensure the stability of complex manipulator control systems and reduce the number of fuzzy rules required.Comparison of experimental and simulation data shows that the controller designed using this algorithm has highly-precise trajectory-tracking control and can control robotic systems with complex characteristics of non-linearity,coupling and uncertainty.Therefore,the proposed algorithm has good practical application prospects and promotes the development of complex control systems.展开更多
This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （D...This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （DW） under thermophilic （55±1 ℃）, 5 L of working volume, three parallel lab-scale conditions. Its mixtures were prepared with a DW content of 25%and 50% and the C/N ratios of mixtures are 13.1 and 17.6, respectively. The effluent dewatering properties were evaluated under stable conditions which the biogas yield and the effluent pH were steady. The natural settleability, biogas yield, centrifugal dewatering, centrifugal supernatant turbidity and specific resistance filtration （SRF） were investigated. The results showed that the effluent dewatering properties of anaerobic co-digestion of mixtures between SS and DW were better than that of anaerobic digestion of SS alone. In the anaerobic digestion system with the feed were SS, mixture of SS and a DW content of 25%and 50% in order, the net biogas yield of secondary sludge in ADSA,ADSB and ADSC were 0.42 0.507 and 0.511 m3 biogass/kg.VS.d ; compared with the biogas yield in anaerobic digestion system A （ADSA）, the biogas yield in anaerobic digestion system B （ADSB） and anaerobic digestion system C （ADSC） had been increased by more than 20% respectively; the SRF of three digested sludge are（were） from 6.8×10^13, 1. 1×10^13 to 5.1×10^12 m/Kg, natural settling rates of 12 h are 26, 37 and 56% and that of 24 h are 32%, 45% and 59% respectively; the centrifugal dewatering rate of 3 min at speed of 1000 rpm were 16%, 31% and 51% respectively; the turbidity of centrifugal supernatant were 804, 754 and 678FTU simultaneously.展开更多
American Dream refers to the belief of the majority of Americans.Through hard work,thrift,and determination,they can surely achieve a better life and live a comfortable life.Such an American Dream has a profound influ...American Dream refers to the belief of the majority of Americans.Through hard work,thrift,and determination,they can surely achieve a better life and live a comfortable life.Such an American Dream has a profound influence on several generations of Americans.American Dream has a close relationship with people' s working life and cultural activities.Death of a Salesman is a typical play about the pursuit and the illusionary of the Dream follower.In Death of a Salesman,the American Dream is the main hero as well as Willy Loman' s spiritual pillar.The pursuit,the realization,and the disillusionment of the American Dream develop with Willy and his family.展开更多
In this study both electric heating and fluid heating were proposed to bakeout the port plug structure being inserted in the middle of the international thermonuclear experimental reactor （ITER） vacuum vessel. The c...In this study both electric heating and fluid heating were proposed to bakeout the port plug structure being inserted in the middle of the international thermonuclear experimental reactor （ITER） vacuum vessel. The coupled thermal and structural analyses were carried out. The results, such as the distributions of the temperature field, thermal stress and thermal deformation of the port plug, were obtained. Based on the American Society of Mechanical Engineers （ASME） criteria, the reliability and feasibility of the heating technique were verified. The results provide detailed information on the selection of a preferable method for future engineering experiments.展开更多
Tensile testing results of spray cast Ni3Al-based superalloy indicated that the yield strength and tensile strength increase with the increasing of temperature and reached maximum at around 760℃, then decrease with t...Tensile testing results of spray cast Ni3Al-based superalloy indicated that the yield strength and tensile strength increase with the increasing of temperature and reached maximum at around 760℃, then decrease with the increasing of temperature. After high temperature isostatic pressing (HIP), yield strength decreased and ductility and tensile strength increased. Stereographic projection showed that no matter at room temperature, medium temperature or high temperature, cracks extend along (111).展开更多
Properties of the triaxial superdeformed （TSD） bands of odd-A Lu isotopes are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the S0（5） （...Properties of the triaxial superdeformed （TSD） bands of odd-A Lu isotopes are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the S0（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the γ-ray energies, the dynamical moments of inertia and the spin of the TSD bands in odd-A Lu isotopes are obtained. The calculation shows that the competition between the pairing and anti-pairing effects exists in these TSD bands. Meanwhile, the SU（3） symmetry in TSD bands are broken more seriously than in superdeformed （SD） bands.展开更多
A laser beam is a heat source with a high energy density;this technol-ogy has been rapidly developed and applied in thefield of welding owing to its potential advantages,and supplements traditional welding techniques.A...A laser beam is a heat source with a high energy density;this technol-ogy has been rapidly developed and applied in thefield of welding owing to its potential advantages,and supplements traditional welding techniques.An in-depth analysis of its operating process could establish a good foundation for its application in China.It is widely understood that the welding process is a highly nonlinear and multi-variable coupling process;it comprises a significant number of complex processes with random uncertain factors.Because of their nonlinear mapping and self-learning characteristics,artificial neural networks(ANNs)have certain advantages in comparison to traditional methods in thefield of welding.Laser welding is a nonlinear dynamic process;these processes still pose a major challenge in thefield of control.Therefore,establishing a stable model is a pre-requisite for achieving accurate control.In this study,the identification and con-trol of radial basis function neural networks in laser welding processes and self-tuning PID control methods are proposed to improve weld quality.Using a MATLAB simulation,it is shown that the proposed method can obtain a good description of the level of nonlinear dynamic control,and that the algorithm iden-tification accuracy is high,practical,and effective.Using this method,the weld width quickly reaches the expected value and the system remains stable,with good robustness.Further,it ensures the stability and dynamic performance of the welding process and improves weld quality.展开更多
Urban rail trains have undergone rapid development in recent years due to their punctuality,high capacity and energy efficiency.Urban trains require frequent start/stop operations and are,therefore,prone to high energ...Urban rail trains have undergone rapid development in recent years due to their punctuality,high capacity and energy efficiency.Urban trains require frequent start/stop operations and are,therefore,prone to high energy losses.As trains have high inertia,the energy that can be recovered from braking comes in short bursts of high power.To effectively recover such braking energy,an onboard supercapacitor system based on a radial basis function neural networkbased sliding mode control system is proposed,which provides robust adaptive performance.The supercapacitor energy storage system is connected to a bidirectional DC/DC converter to provide traction energy or absorb regenerative braking energy.In the Boost and Buck modes,the state-space averaging method is used to establish a model and perform exact linearization.An adaptive sliding mode controller is designed,and simulation results show that it can effectively solve the problems of low energy utilization and large voltage fluctuations in urban rail electricity grids,and maximise the recovery and utilization of regenerative braking energy.展开更多
Urban rail transit can solve the current inconvenient transportation problem for China’s large urban population.A compound onboard energy storage system can meet vehicles’traction requirements and recover energy in ...Urban rail transit can solve the current inconvenient transportation problem for China’s large urban population.A compound onboard energy storage system can meet vehicles’traction requirements and recover energy in vehicles’braking stage to improve energy utilisation.However,the composite onboard energy storage system has several concerns,such as its power and energy demand,battery aging,and maintenance costs.Therefore,the NSGA-II algorithm is proposed to optimise matching the composite energy storage system parameters for urban rail trains.The NSGA-II algorithm was used with an improved elite retention strategy to optimise the parameters matching of the composite power supply.The optimisation’s objective concerns the replacement costs and economy of the composite power supply.The method increases the vertical diversity of searching and avoids genetic precocity.The NSGA-II algorithm calls the simulation model of composite power supply in real-time and simultaneously optimises the composite power supply and control parameters.The Pareto set of optimisation objectives and corresponding parameters and control strategies of composite power supply are obtained.The NSGA-II algorithm can optimise the composite energy storage system’s parameters and improve the train and the composite power supply’s performance indexes.The algorithm greatly reduces the composite power supply’s capacitance and reduces the system’s total energy consumption.Then,the multi-component energy loss caused by the multi-power source system can be effectively controlled.The total capacitance is reduced by 12.1%,the battery life is prolonged by 18.86%,and the optimised composite power supply’s energy storage is increased by 17.6%.展开更多
The energy consumption of train operation occupies a large proportion of the total consumption of railway transportation.In order to improve the oper-ating energy utilization rate of trains,a multi-objective particle ...The energy consumption of train operation occupies a large proportion of the total consumption of railway transportation.In order to improve the oper-ating energy utilization rate of trains,a multi-objective particle swarm optimiza-tion(MPSO)algorithm with energy consumption,punctuality and parking accuracy as the objective and safety as the constraint is built.To accelerate its the convergence process,the train operation progression is divided into several modes according to the train speed-distance curve.A human-computer interactive particle swarm optimization algorithm is proposed,which presents the optimized results after a certain number of iterations to the decision maker,and the satisfac-tory outcomes can be obtained after a limited number of adjustments.The multi-objective particle swarm optimization(MPSO)algorithm is used to optimize the train operation process.An algorithm based on the important relationship between the objective and the preference information of the given reference points is sug-gested to overcome the shortcomings of the existing algorithms.These methods significantly increase the computational complexity and convergence of the algo-rithm.An adaptive fuzzy logic system that can simultaneously utilize experience information andfield data information is proposed to adjust the consequences of off-line optimization in real time,thereby eliminating the influence of uncertainty on train operation.After optimization and adjustment,the whole running time has been increased by 0.5 s,the energy consumption has been reduced by 12%,the parking accuracy has been increased by 8%,and the comprehensive performance has been enhanced.展开更多
There is general agreement that culture should be taught in the foreign language classroom of Higher Vocational College,but just what this means is unclear.The thesis is concerned with why,what and how of teaching cul...There is general agreement that culture should be taught in the foreign language classroom of Higher Vocational College,but just what this means is unclear.The thesis is concerned with why,what and how of teaching culture.Firstly,it will be demonstrated that teaching foreign language is not the same as giving syntactic structures,but mainly incorporates some cultures elements.Secondly,it suggests which culture is taught in the foreign language classroom.Furthermore,by means of some methods an attempt will be made to incorporate culture into the classroom.As a result of the study shows that Culture has taken an important place in foreign language classroom of Higher Vocational College.展开更多
With the metaverse being the development direction of the next generation Internet,the popularity of intelligent devices,and the maturity of various emerging technologies,more and more intelligent devices try to conne...With the metaverse being the development direction of the next generation Internet,the popularity of intelligent devices,and the maturity of various emerging technologies,more and more intelligent devices try to connect to the Internet,which poses a major threat to the management and security protection of network equipment.At present,the mainstream method of network equipment identification in the metaverse is to obtain the network traffic data generated in the process of device communication,extract the device features through analysis and processing,and identify the device based on a variety of learning algorithms.Such methods often require manual participation,and it is difficult to capture the small differences between similar devices,leading to identification errors.Therefore,we propose a deep learning device recognition method based on a spatial attention mechanism.Firstly,we extract the required feature fields from the acquired network traffic data.Then,we normalize the data and convert it into grayscale images.After that,we add a spatial attention mechanism to CNN and MLP respectively to increase the difference between similar network devices and further improve the recognition accuracy.Finally,we identify devices based on the deep learning model.A large number of experiments were carried out on 31 types of network devices such as web cameras,wireless routers,and smartwatches.The results show that the accuracy of the proposed recognition method based on the spatial attention mechanism is increased by 0.8%and 2.0%,respectively,compared with the recognition method based only on the deep learning model under the CNN and MLP models.The method proposed in this paper is significantly superior to the existing method of device-type recognition based only on a deep learning model.展开更多
Conventional financial risk assessment is not accurate and its adaptive assessment ability is low.In order to solve this problem,a financial risk assessment model based on big data is proposed.In this method,the quant...Conventional financial risk assessment is not accurate and its adaptive assessment ability is low.In order to solve this problem,a financial risk assessment model based on big data is proposed.In this method,the quantitative analysis method is adopted to analyze the explanatory variable model and the control variable model of financial risk assessment.The market-to-book ratio,asset–liability ratio,cash flow ratio and financing structure model are adopted as constraint parameters to construct a big data analysis model for financial risk assessment.On this basis,the adaptive fuzzy weighted control method is adopted for information fusion of financial risk assessment data and big data classification,and the asset income control and innovative evaluation model are adopted for linear planning and square fitting during financial risk assessment.Based on the intervention factors of financial market participants,quantitative regression analysis is performed,and according to the economic game theory,big data analysis and prediction of financial risk assessment are performed through the regression analysis method.Then the big data fusion and clustering algorithms are adopted for financial risk assessment.The simulation results show that this method can provide a relatively high accuracy in financial risk assessment,and has relatively strong adaptive evaluation capability to the risk coefficient,so it has a good application value in the prevention and control of risk factors in financial systems.展开更多
Quantitative structure-property relationship(QSPR)models were developed for prediction of photolysis half-life(t_(1/2))of polychlorinated biphenyls(PCBs)in water under ultraviolet(UV)radiation.Quantum chemical descrip...Quantitative structure-property relationship(QSPR)models were developed for prediction of photolysis half-life(t_(1/2))of polychlorinated biphenyls(PCBs)in water under ultraviolet(UV)radiation.Quantum chemical descriptors computed by the PM3 Hamiltonian software were used as independent variables.The cross-validated Q^(2)_(cum)value for the optimal QSPR model is 0.966,indicating good prediction capability for lg t_(1/2)values of PCBs in water.The QSPR results show that the largest negative atomic charge on a carbon atom(Q-C)and the standard heat of formation(ΔH_(f))have a dominant effect on t_(1/2)values of PCBs.Higher Q_(C)^(-)values or lowerΔHf values of the PCBs leads to higher lg t_(1/2)values.In addition,the lg t_(1/2)values of PCBs increase with the increase in the energy of the highest occupied molecular orbital values.Increasing the largest positive atomic charge on a chlorine atom and the most positive net atomic charge on a hydrogen atom in PCBs leads to the decrease of lg t_(1/2)values.展开更多
A novel dinuclear copper(Ⅱ)coordination compound,[CuⅡ(Hpdc)(phen)Cl][CuⅡ(pdc)(phen)]·4 H2 O(1,H2 pdc=pyridine-2,6-dicarboxylic acid,phen=1,10-phenanthroline),has been obtained by an ionothermal method using th...A novel dinuclear copper(Ⅱ)coordination compound,[CuⅡ(Hpdc)(phen)Cl][CuⅡ(pdc)(phen)]·4 H2 O(1,H2 pdc=pyridine-2,6-dicarboxylic acid,phen=1,10-phenanthroline),has been obtained by an ionothermal method using the ionic liquid 3-butyl-1-methylimidazolium bromide([Bmim]Br)as solvent,and fully characterized by elemental analyses,energy-dispersive X-ray spectroscopy(EDX),IR and single-crystal X-ray diffraction.1 belongs to the triclinic system,space group■with a=11.406(4),b=11.801(5),c=16.093(6)?,α=106.124(6)°,β=113.480(7)°,γ=93.853(7)°,Z=2,V=1942.3(13)?3,Dc=1.570 g·cm-3,F(000)=928,μ=1.235 mm-1,the final R=0.0588,wR=0.1369 and S=1.013.The compound exhibits a two-dimensional layered structure constructed by[CuⅡ(Hpdc)(phen)Cl]and[CuⅡ(pdc)(phen)]fragments via the hydrogen bonds andπ-πstacking interactions.In addition,its thermal properties and magnetic behaviors were also studied in detail.The magnetic properties revealed that there is a ferromagnetic interaction between Cu…Cu in 1.展开更多
基金financially supported by the Scientific and Technological Plan Projects of Guangzhou City(202103040001),P.R.Chinathe Project of Science and Technology Department of Henan Province(222102240074)the Key Research Programs of Higher Education Institutions of Henan Province(24B150009)。
文摘Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.
文摘In the context of the new period,the continuous growth of social and economic levels and the rapid update of information technology have significantly impacted the business management of Chinese enterprises,presenting substantial challenges.The intensification of market competition exerts development pressure on many enterprises,and coupled with the unstable strength of some businesses,numerous problems in business management arise.These issues hinder the smooth execution of various business activities.Therefore,it is crucial to ensure effective business administration to conduct different business activities in an orderly manner,promptly avoid adverse risks,and strengthen control over multiple factors.The innovation and improvement of business administration are of great significance for enhancing the management level and market competitiveness of modern enterprises,accelerating their healthy development,and creating numerous opportunities.Consequently,this paper analyzes and explores the development trends of enterprise business administration and the innovation of management models for reference.
文摘The physical features exhibited by Hermite-Gaussian （HC） beams propagating in nonlocal nonlinear media with Gaussian-shaped response are discussed with an approximate variational method.Using direct numerical simulations,we find that the beam properties in the normalized system are different with the change of the degree of nonlocality.It is shown that initial HG profiles break up into several individual beams with propagation when the degree of nonlocality α is small.HG beams can propagate stably when a is large enough.
基金supported by the National Natural Science Foundation of China (No. 50572008)
文摘The effects of ZnO-B2O3 （ZB2） on the sintering behavior and microwave dielectric properties of （Ca0.254Li0.19Sm0.14）TiO3 ceramics were investigated. The densities of the specimens reached the maximum value by adding 3 wt.% ZB2 and then decreased. The sintering temperature of the specimens was lowered from 1300 to 1100℃ without degradation of the microwave dielectric properties. The （Ca0.254Li0.19Sm0.14）TiO3＋ 3 wt.% ZB2 sintered at 1100℃ for 3 h showed good microwave dielectric properties, εr= 108.2, Qf= 6545 GHz, and rf= 6.5 ppm/℃, respectively, indicating that ZB2 was an effective sintering aid to improve the densification and microwave dielectric properties of （Ca0.254Li0.19Sm0.14）TiO3 ceramics.
基金Project(10405024) supported by the National Natural Science Foundation of ChinaProject supported by International Thermonuclear Experimental Reactor Organization in France
文摘Modal analysis and seismic response analysis were carried out for the equatorial diagnostic port plug of international thermonuclear experimental reactor (ITER). The aim of the theoretical analysis is to verify structural strength and reliability of the device. The working condition includes one-dimensional seismic wave and two-dimensional seismic wave. Modal analysis of the device shows that primary vibration is inclined to occur in low-order modes. The horizontal (X-direction, Y-direction) maximum vibration appears at the first and the fourth eigen modes, with the natural frequency of 70.59 and 215.88 Hz respectively, and the vertical (Z-direction) primary vibration appears at the second eigen mode with the natural frequency of 82.85 Hz. According to the results of the finite element analysis (FEA) program, the weak portions of the device are distributed in the joint of port body with blanket shielding module (BSM) and inner side wall of ribbed plate for lifting flange, the maximum von Mises stress is 14.8 MPa with the Y-direction seismic wave. In accordance with the design criteria, the destructive effect is far below the failure boundary, and the structural reliability of the equatorial diagnostic port plug can meet the requirements of the design specifications.
基金the project of science and technology of Henan province under Grant No.14210221036.
文摘Multi-joint manipulator systems are subject to nonlinear influences such as frictional characteristics,random disturbances and load variations.To account for uncertain disturbances in the operation of manipulators,we propose an adaptive manipulator control method based on a multi-joint fuzzy system,in which the upper bound information of the fuzzy system is constant and the state variables of the manipulator control system are measurable.The control algorithm of the system is a MIMO(multi-input-multi-output)fuzzy system that can approximate system error by using a robust adaptive control law to eliminate the shadow caused by approximation error.It can ensure the stability of complex manipulator control systems and reduce the number of fuzzy rules required.Comparison of experimental and simulation data shows that the controller designed using this algorithm has highly-precise trajectory-tracking control and can control robotic systems with complex characteristics of non-linearity,coupling and uncertainty.Therefore,the proposed algorithm has good practical application prospects and promotes the development of complex control systems.
文摘This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （DW） under thermophilic （55±1 ℃）, 5 L of working volume, three parallel lab-scale conditions. Its mixtures were prepared with a DW content of 25%and 50% and the C/N ratios of mixtures are 13.1 and 17.6, respectively. The effluent dewatering properties were evaluated under stable conditions which the biogas yield and the effluent pH were steady. The natural settleability, biogas yield, centrifugal dewatering, centrifugal supernatant turbidity and specific resistance filtration （SRF） were investigated. The results showed that the effluent dewatering properties of anaerobic co-digestion of mixtures between SS and DW were better than that of anaerobic digestion of SS alone. In the anaerobic digestion system with the feed were SS, mixture of SS and a DW content of 25%and 50% in order, the net biogas yield of secondary sludge in ADSA,ADSB and ADSC were 0.42 0.507 and 0.511 m3 biogass/kg.VS.d ; compared with the biogas yield in anaerobic digestion system A （ADSA）, the biogas yield in anaerobic digestion system B （ADSB） and anaerobic digestion system C （ADSC） had been increased by more than 20% respectively; the SRF of three digested sludge are（were） from 6.8×10^13, 1. 1×10^13 to 5.1×10^12 m/Kg, natural settling rates of 12 h are 26, 37 and 56% and that of 24 h are 32%, 45% and 59% respectively; the centrifugal dewatering rate of 3 min at speed of 1000 rpm were 16%, 31% and 51% respectively; the turbidity of centrifugal supernatant were 804, 754 and 678FTU simultaneously.
文摘American Dream refers to the belief of the majority of Americans.Through hard work,thrift,and determination,they can surely achieve a better life and live a comfortable life.Such an American Dream has a profound influence on several generations of Americans.American Dream has a close relationship with people' s working life and cultural activities.Death of a Salesman is a typical play about the pursuit and the illusionary of the Dream follower.In Death of a Salesman,the American Dream is the main hero as well as Willy Loman' s spiritual pillar.The pursuit,the realization,and the disillusionment of the American Dream develop with Willy and his family.
基金supported by the ITER Organizationthe Diagnostic Working Group of ASIPP
文摘In this study both electric heating and fluid heating were proposed to bakeout the port plug structure being inserted in the middle of the international thermonuclear experimental reactor （ITER） vacuum vessel. The coupled thermal and structural analyses were carried out. The results, such as the distributions of the temperature field, thermal stress and thermal deformation of the port plug, were obtained. Based on the American Society of Mechanical Engineers （ASME） criteria, the reliability and feasibility of the heating technique were verified. The results provide detailed information on the selection of a preferable method for future engineering experiments.
文摘Tensile testing results of spray cast Ni3Al-based superalloy indicated that the yield strength and tensile strength increase with the increasing of temperature and reached maximum at around 760℃, then decrease with the increasing of temperature. After high temperature isostatic pressing (HIP), yield strength decreased and ductility and tensile strength increased. Stereographic projection showed that no matter at room temperature, medium temperature or high temperature, cracks extend along (111).
基金Supported by the National Natural Science Foundation of China under Grant No.10475026the Natural Science Foundation of Zhejiang Province under Grant No.KY607518
文摘Properties of the triaxial superdeformed （TSD） bands of odd-A Lu isotopes are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the S0（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the γ-ray energies, the dynamical moments of inertia and the spin of the TSD bands in odd-A Lu isotopes are obtained. The calculation shows that the competition between the pairing and anti-pairing effects exists in these TSD bands. Meanwhile, the SU（3） symmetry in TSD bands are broken more seriously than in superdeformed （SD） bands.
基金This work was supported by the Youth Backbone Teacher’s training program for Henan colleges and universities under Grant No.2016ggjs-287the Science and Technology Project of Henan province,under Grant Nos.172102210124 and 202102210269the Key Scientific Research Projects in Colleges and Universities in Henan,Grant No.18B460003.
文摘A laser beam is a heat source with a high energy density;this technol-ogy has been rapidly developed and applied in thefield of welding owing to its potential advantages,and supplements traditional welding techniques.An in-depth analysis of its operating process could establish a good foundation for its application in China.It is widely understood that the welding process is a highly nonlinear and multi-variable coupling process;it comprises a significant number of complex processes with random uncertain factors.Because of their nonlinear mapping and self-learning characteristics,artificial neural networks(ANNs)have certain advantages in comparison to traditional methods in thefield of welding.Laser welding is a nonlinear dynamic process;these processes still pose a major challenge in thefield of control.Therefore,establishing a stable model is a pre-requisite for achieving accurate control.In this study,the identification and con-trol of radial basis function neural networks in laser welding processes and self-tuning PID control methods are proposed to improve weld quality.Using a MATLAB simulation,it is shown that the proposed method can obtain a good description of the level of nonlinear dynamic control,and that the algorithm iden-tification accuracy is high,practical,and effective.Using this method,the weld width quickly reaches the expected value and the system remains stable,with good robustness.Further,it ensures the stability and dynamic performance of the welding process and improves weld quality.
基金the Science and Technology Project of Henan Province under Grant No.14210221036.
文摘Urban rail trains have undergone rapid development in recent years due to their punctuality,high capacity and energy efficiency.Urban trains require frequent start/stop operations and are,therefore,prone to high energy losses.As trains have high inertia,the energy that can be recovered from braking comes in short bursts of high power.To effectively recover such braking energy,an onboard supercapacitor system based on a radial basis function neural networkbased sliding mode control system is proposed,which provides robust adaptive performance.The supercapacitor energy storage system is connected to a bidirectional DC/DC converter to provide traction energy or absorb regenerative braking energy.In the Boost and Buck modes,the state-space averaging method is used to establish a model and perform exact linearization.An adaptive sliding mode controller is designed,and simulation results show that it can effectively solve the problems of low energy utilization and large voltage fluctuations in urban rail electricity grids,and maximise the recovery and utilization of regenerative braking energy.
基金Henan province’s project of science and technology under Grant No.202102210134.
文摘Urban rail transit can solve the current inconvenient transportation problem for China’s large urban population.A compound onboard energy storage system can meet vehicles’traction requirements and recover energy in vehicles’braking stage to improve energy utilisation.However,the composite onboard energy storage system has several concerns,such as its power and energy demand,battery aging,and maintenance costs.Therefore,the NSGA-II algorithm is proposed to optimise matching the composite energy storage system parameters for urban rail trains.The NSGA-II algorithm was used with an improved elite retention strategy to optimise the parameters matching of the composite power supply.The optimisation’s objective concerns the replacement costs and economy of the composite power supply.The method increases the vertical diversity of searching and avoids genetic precocity.The NSGA-II algorithm calls the simulation model of composite power supply in real-time and simultaneously optimises the composite power supply and control parameters.The Pareto set of optimisation objectives and corresponding parameters and control strategies of composite power supply are obtained.The NSGA-II algorithm can optimise the composite energy storage system’s parameters and improve the train and the composite power supply’s performance indexes.The algorithm greatly reduces the composite power supply’s capacitance and reduces the system’s total energy consumption.Then,the multi-component energy loss caused by the multi-power source system can be effectively controlled.The total capacitance is reduced by 12.1%,the battery life is prolonged by 18.86%,and the optimised composite power supply’s energy storage is increased by 17.6%.
基金supported by the project of science and technology of Henan province under Grant No.202102210134.
文摘The energy consumption of train operation occupies a large proportion of the total consumption of railway transportation.In order to improve the oper-ating energy utilization rate of trains,a multi-objective particle swarm optimiza-tion(MPSO)algorithm with energy consumption,punctuality and parking accuracy as the objective and safety as the constraint is built.To accelerate its the convergence process,the train operation progression is divided into several modes according to the train speed-distance curve.A human-computer interactive particle swarm optimization algorithm is proposed,which presents the optimized results after a certain number of iterations to the decision maker,and the satisfac-tory outcomes can be obtained after a limited number of adjustments.The multi-objective particle swarm optimization(MPSO)algorithm is used to optimize the train operation process.An algorithm based on the important relationship between the objective and the preference information of the given reference points is sug-gested to overcome the shortcomings of the existing algorithms.These methods significantly increase the computational complexity and convergence of the algo-rithm.An adaptive fuzzy logic system that can simultaneously utilize experience information andfield data information is proposed to adjust the consequences of off-line optimization in real time,thereby eliminating the influence of uncertainty on train operation.After optimization and adjustment,the whole running time has been increased by 0.5 s,the energy consumption has been reduced by 12%,the parking accuracy has been increased by 8%,and the comprehensive performance has been enhanced.
文摘There is general agreement that culture should be taught in the foreign language classroom of Higher Vocational College,but just what this means is unclear.The thesis is concerned with why,what and how of teaching culture.Firstly,it will be demonstrated that teaching foreign language is not the same as giving syntactic structures,but mainly incorporates some cultures elements.Secondly,it suggests which culture is taught in the foreign language classroom.Furthermore,by means of some methods an attempt will be made to incorporate culture into the classroom.As a result of the study shows that Culture has taken an important place in foreign language classroom of Higher Vocational College.
基金supported by the National Key Research and Development Program of China(No.2022YFB3102900)the National Natural Science Foundation of China(No.U1804263,62172435 and 62002386)the Zhongyuan Science and Technology Innovation Leading Talent Project,China(No.214200510019)
文摘With the metaverse being the development direction of the next generation Internet,the popularity of intelligent devices,and the maturity of various emerging technologies,more and more intelligent devices try to connect to the Internet,which poses a major threat to the management and security protection of network equipment.At present,the mainstream method of network equipment identification in the metaverse is to obtain the network traffic data generated in the process of device communication,extract the device features through analysis and processing,and identify the device based on a variety of learning algorithms.Such methods often require manual participation,and it is difficult to capture the small differences between similar devices,leading to identification errors.Therefore,we propose a deep learning device recognition method based on a spatial attention mechanism.Firstly,we extract the required feature fields from the acquired network traffic data.Then,we normalize the data and convert it into grayscale images.After that,we add a spatial attention mechanism to CNN and MLP respectively to increase the difference between similar network devices and further improve the recognition accuracy.Finally,we identify devices based on the deep learning model.A large number of experiments were carried out on 31 types of network devices such as web cameras,wireless routers,and smartwatches.The results show that the accuracy of the proposed recognition method based on the spatial attention mechanism is increased by 0.8%and 2.0%,respectively,compared with the recognition method based only on the deep learning model under the CNN and MLP models.The method proposed in this paper is significantly superior to the existing method of device-type recognition based only on a deep learning model.
文摘Conventional financial risk assessment is not accurate and its adaptive assessment ability is low.In order to solve this problem,a financial risk assessment model based on big data is proposed.In this method,the quantitative analysis method is adopted to analyze the explanatory variable model and the control variable model of financial risk assessment.The market-to-book ratio,asset–liability ratio,cash flow ratio and financing structure model are adopted as constraint parameters to construct a big data analysis model for financial risk assessment.On this basis,the adaptive fuzzy weighted control method is adopted for information fusion of financial risk assessment data and big data classification,and the asset income control and innovative evaluation model are adopted for linear planning and square fitting during financial risk assessment.Based on the intervention factors of financial market participants,quantitative regression analysis is performed,and according to the economic game theory,big data analysis and prediction of financial risk assessment are performed through the regression analysis method.Then the big data fusion and clustering algorithms are adopted for financial risk assessment.The simulation results show that this method can provide a relatively high accuracy in financial risk assessment,and has relatively strong adaptive evaluation capability to the risk coefficient,so it has a good application value in the prevention and control of risk factors in financial systems.
基金The research was supported by the Open Foundation of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(No.2009490511)the special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(No.10Y08ESPCN)the National High Technology Research and Development Program of China(No.2009AA05Z306).
文摘Quantitative structure-property relationship(QSPR)models were developed for prediction of photolysis half-life(t_(1/2))of polychlorinated biphenyls(PCBs)in water under ultraviolet(UV)radiation.Quantum chemical descriptors computed by the PM3 Hamiltonian software were used as independent variables.The cross-validated Q^(2)_(cum)value for the optimal QSPR model is 0.966,indicating good prediction capability for lg t_(1/2)values of PCBs in water.The QSPR results show that the largest negative atomic charge on a carbon atom(Q-C)and the standard heat of formation(ΔH_(f))have a dominant effect on t_(1/2)values of PCBs.Higher Q_(C)^(-)values or lowerΔHf values of the PCBs leads to higher lg t_(1/2)values.In addition,the lg t_(1/2)values of PCBs increase with the increase in the energy of the highest occupied molecular orbital values.Increasing the largest positive atomic charge on a chlorine atom and the most positive net atomic charge on a hydrogen atom in PCBs leads to the decrease of lg t_(1/2)values.
文摘A novel dinuclear copper(Ⅱ)coordination compound,[CuⅡ(Hpdc)(phen)Cl][CuⅡ(pdc)(phen)]·4 H2 O(1,H2 pdc=pyridine-2,6-dicarboxylic acid,phen=1,10-phenanthroline),has been obtained by an ionothermal method using the ionic liquid 3-butyl-1-methylimidazolium bromide([Bmim]Br)as solvent,and fully characterized by elemental analyses,energy-dispersive X-ray spectroscopy(EDX),IR and single-crystal X-ray diffraction.1 belongs to the triclinic system,space group■with a=11.406(4),b=11.801(5),c=16.093(6)?,α=106.124(6)°,β=113.480(7)°,γ=93.853(7)°,Z=2,V=1942.3(13)?3,Dc=1.570 g·cm-3,F(000)=928,μ=1.235 mm-1,the final R=0.0588,wR=0.1369 and S=1.013.The compound exhibits a two-dimensional layered structure constructed by[CuⅡ(Hpdc)(phen)Cl]and[CuⅡ(pdc)(phen)]fragments via the hydrogen bonds andπ-πstacking interactions.In addition,its thermal properties and magnetic behaviors were also studied in detail.The magnetic properties revealed that there is a ferromagnetic interaction between Cu…Cu in 1.
