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Interfacial Evolution and Accelerated Aging Mechanism for LiFePO4/Graphite Pouch Batteries Under Multi-Step Indirect Activation 认领 引用
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作者 Yun Liu Jinyang Dong +11 位作者 Jialong Zhou Yibiao Guan Yimin Wei Jiayu Zhao Jinding Liang Xixiu Shi Kang Yan Yun Lu Ning Li Yuefeng Su Feng Wu Lai Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2026年第4期735-754,共20页
The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO4(LFP)/graphite batteries;there is a lack of systematic under... The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO4(LFP)/graphite batteries;there is a lack of systematic understanding of the spatial distribution of the EEI interface layer and the dissolve of Fe ions,especially in terms of the mechanism of the cathode-electrolyte interphase(CEI),solid electrolyte interphase(SEI),and iron dissolution.In this study,aged cells were subjected to continuous activation with constant current and multi-step segmented indirect activation(IA)and analyzed for capacity fade,impedance growth,and active Li+mass loss at the EEI and nanoscale levels.The interaction between dissolved Fe2+and the EEI in LFP/graphite pouch batteries was proposed and verified.The findings indicate that during IA process,the electric field facilitates the migration of solvated ions toward the electrodes,while simultaneously inhibiting the formation of organic species such as ROCO2Li.The SEI primarily consists of a mixture of organic and inorganic small molecules,forming a continuous and uniform film on the electrode surface.This study demonstrates that IA favors the formation of a uniform EEI and offers constructive insights for advancing accelerated lifetime prediction strategies in lithium-ion batteries. 展开更多
关键词 Accelerated aging Electrode/electrolyte interface Multi-step segmented indirect activation EEI film Dissolve of Fe ions
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General multi-steps variable-coefficient formulation for computing quasi-periodic solutions with multiple base frequencies 认领 引用
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作者 Junqing Wu Ling Hong +1 位作者 Mingwu Li Jun Jiang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第1期260-275,共16页
Quasi-periodic solutions with multiple base frequencies exhibit the feature of 2π-periodicity with respect to each of the hyper-time variables.However,it remains a challenge work,due to the lack of effective solution... Quasi-periodic solutions with multiple base frequencies exhibit the feature of 2π-periodicity with respect to each of the hyper-time variables.However,it remains a challenge work,due to the lack of effective solution methods,to solve and track the quasi-periodic solutions with multiple base frequencies until now.In this work,a multi-steps variable-coefficient formulation is proposed,which provides a unified framework to enable either harmonic balance method or collocation method or finite difference method to solve quasi-periodic solutions with multiple base frequencies.For this purpose,a method of alternating U and S domain is also developed to efficiently evaluate the nonlinear force terms.Furthermore,a new robust phase condition is presented for all of the three methods to make them track the quasi-periodic solutions with prior unknown multiple base frequencies,while the stability of the quasi-periodic solutions is assessed by mean of Lyapunov exponents.The feasibility of the constructed methods under the above framework is verified by application to three nonlinear systems. 展开更多
关键词 Multi-steps variable-coefficient formulation Phase condition Harmonic balance method Finite difference method Collocation method
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A MIXED FINITE ELEMENT AND UPWIND MIXED FINITE ELEMENT MULTI-STEP METHOD FOR THE THREE-DIMENSIONAL POSITIVE SEMI-DEFINITE DARCY-FORCHHEIMER MISCIBLE DISPLACEMENT PROBLEM 认领 引用
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作者 Yirang YUAN Changfeng LI +1 位作者 Huailing SONG Tongjun SUN 《Acta Mathematica Scientia》 SCIE CSCD 2025年第2期715-736,共22页
In this paper,a composite numerical scheme is proposed to solve the threedimensional Darcy-Forchheimer miscible displacement problem with positive semi-definite assumptions.A mixed finite element is used for the fow e... In this paper,a composite numerical scheme is proposed to solve the threedimensional Darcy-Forchheimer miscible displacement problem with positive semi-definite assumptions.A mixed finite element is used for the fow equation.The velocity and pressure are computed simultaneously.The accuracy of velocity is improved one order.The concentration equation is solved by using mixed finite element,multi-step difference and upwind approximation.A multi-step method is used to approximate time derivative for improving the accuracy.The upwind approximation and an expanded mixed finite element are adopted to solve the convection and diffusion,respectively.The composite method could compute the diffusion flux and its gradient.It possibly becomes an eficient tool for solving convection-dominated diffusion problems.Firstly,the conservation of mass holds.Secondly,the multi-step method has high accuracy.Thirdly,the upwind approximation could avoid numerical dispersion.Using numerical analysis of a priori estimates and special techniques of differential equations,we give an error estimates for a positive definite problem.Numerical experiments illustrate its computational efficiency and feasibility of application. 展开更多
关键词 Darcy-Forchheimer fow three-dimensional positive semi-definite problem upwind mixed finite element multi-step method conservation of mass convergence analysis
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MPMS-SGH:Multi-parameter Multi-step Prediction Model for Solar Greenhouse 认领 引用 被引量：2
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作者 JI Ronghua WANG Wenxuan +2 位作者 AN Dong QI Shaotian LIU Jincun 《农业机械学报》 EI CAS CSCD 北大核心 2025年第7期265-278,共14页
Accurately predicting environmental parameters in solar greenhouses is crucial for achieving precise environmental control.In solar greenhouses,temperature,humidity,and light intensity are crucial environmental parame... Accurately predicting environmental parameters in solar greenhouses is crucial for achieving precise environmental control.In solar greenhouses,temperature,humidity,and light intensity are crucial environmental parameters.The monitoring platform collected data on the internal environment of the solar greenhouse for one year,including temperature,humidity,and light intensity.Additionally,meteorological data,comprising outdoor temperature,outdoor humidity,and outdoor light intensity,was gathered during the same time frame.The characteristics and interrelationships among these parameters were investigated by a thorough analysis.The analysis revealed that environmental parameters in solar greenhouses displayed characteristics such as temporal variability,non-linearity,and periodicity.These parameters exhibited complex coupling relationships.Notably,these characteristics and coupling relationships exhibited pronounced seasonal variations.The multi-parameter multi-step prediction model for solar greenhouse(MPMS-SGH)was introduced,aiming to accurately predict three key greenhouse environmental parameters,and the model had certain seasonal adaptability.MPMS-SGH was structured with multiple layers,including an input layer,a preprocessing layer,a feature extraction layer,and a prediction layer.The input layer was used to generate the original sequence matrix,which included indoor temperature,indoor humidity,indoor light intensity,as well as outdoor temperature and outdoor light intensity.Then the preprocessing layer normalized,decomposed,and positionally encoded the original sequence matrix.In the feature extraction layer,the time attention mechanism and frequency attention mechanism were used to extract features from the trend component and the seasonal component,respectively.Finally,the prediction layer used a multi-layer perceptron to perform multi-step prediction of indoor environmental parameters(i.e.temperature,humidity,and light intensity).The parameter selection experiment evaluated the predictive performance of MPMS-SGH on input and output sequences of different lengths.The results indicated that with a constant output sequence length,the prediction accuracy of MPMS-SGH was firstly increased and then decreased with the increase of input sequence length.Specifically,when the input sequence length was 100,MPMS-SGH had the highest prediction accuracy,with RMSE of 0.22℃,0.28%,and 250lx for temperature,humidity,and light intensity,respectively.When the length of the input sequence remained constant,as the length of the output sequence increased,the accuracy of the model in predicting the three environmental parameters was continuously decreased.When the length of the output sequence exceeded 45,the prediction accuracy of MPMS-SGH was significantly decreased.In order to achieve the best balance between model size and performance,the input sequence length of MPMS-SGH was set to be 100,while the output sequence length was set to be 35.To assess MPMS-SGH’s performance,comparative experiments with four prediction models were conducted:SVR,STL-SVR,LSTM,and STL-LSTM.The results demonstrated that MPMS-SGH surpassed all other models,achieving RMSE of 0.15℃for temperature,0.38%for humidity,and 260lx for light intensity.Additionally,sequence decomposition can contribute to enhancing MPMS-SGH’s prediction performance.To further evaluate MPMS-SGH’s capabilities,its prediction accuracy was tested across different seasons for greenhouse environmental parameters.MPMS-SGH had the highest accuracy in predicting indoor temperature and the lowest accuracy in predicting humidity.And the accuracy of MPMS-SGH in predicting environmental parameters of the solar greenhouse fluctuated with seasons.MPMS-SGH had the highest accuracy in predicting the temperature inside the greenhouse on sunny days in spring(R2=0.91),the highest accuracy in predicting the humidity inside the greenhouse on sunny days in winter(R2=0.83),and the highest accuracy in predicting the light intensity inside the greenhouse on cloudy days in autumm(R2=0.89).MPMS-SGH had the lowest accuracy in predicting three environmental parameters in a sunny summer greenhouse. 展开更多
关键词 solar greenhouse environmental parameter time series multi-step prediction
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A Novel Multi-Step Numerical Framework for Ice Accretion Prediction Based on Unsteady Water Film Dynamics 认领 引用
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作者 Ke Shen Dan Zeng +2 位作者 Changhao Wang Lei Wang Yuliang Dong 《Frontiers in Heat and Mass Transfer》 EI CAS 2025年第6期1957-1980,共24页
Ice accretion on aircraft poses a critical threat to flight safety by significantly altering aerodynamic performance.This study presents a novel numerical framework for ice accretion prediction,developed by extending ... Ice accretion on aircraft poses a critical threat to flight safety by significantly altering aerodynamic performance.This study presents a novel numerical framework for ice accretion prediction,developed by extending the Myers model and incorporating an advanced multi-step approach.The proposed framework integrates ice layer growth into the modeling of unsteady water film dynamics and introduces a revised criterion for determining the icing condi-tion.A multi-step scheme,accounting for the continuous variation of physical parameters,is implemented to enhance computational accuracy.The framework is validated through simulations on both 2D and 3D configurations.For the NACA0012 airfoil,the model demonstrates strong adaptability to both rime and glaze ice scenarios,with simulated ice shapes and thicknesses showing close agreement with experimental data,especially under low-temperature rime ice scenarios.In glaze ice cases,the framework effectively captures the leading-edge ice thickness and horn formation,albeit with minor positional deviations.For the GLC-305 swept wing,the approach accurately reproduces the primary ice shape features and overall thickness distribution.However,discrepancies in icing extent and thickness persist under rime scenarios due to the limitations of the single-step strategy.In glaze ice scenarios,the model captures the general trend of ice horn development,though positional and thickness deviations remain.Overall,the developed framework improves the precision of ice accretion simulations and offers a promising tool for advancing aircraft safety.Future research will aim to refine the multi-step framework to further improve its robustness and accuracy in complex,3D icing environments. 展开更多
关键词 Ice accretion numerical study Myers model multi-step water film dynamics
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Mode-pairing quantum key distribution with multi-step advantage distillation 认领 引用
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作者 Shizhuo Li Xin Liu +1 位作者 Zhenrong Zhang Kejin Wei 《Chinese Physics B》 SCIE EI CAS CSCD 2025年第9期85-95,共11页
The advantage distillation(AD)technology has been proven to effectively improve the secret key rate and the communication distance of quantum key distribution(QKD).The mode-pairing quantum key distribution(MP-QKD)prot... The advantage distillation(AD)technology has been proven to effectively improve the secret key rate and the communication distance of quantum key distribution(QKD).The mode-pairing quantum key distribution(MP-QKD)protocol can overcome a fundamental physical limit,known as the Pirandola-Laurenza-Ottaviani-Banchi bound,without requiring global phase-locking.In this work,we propose a method based on multi-step AD to further enhance the performance of MP-QKD.The simulation results show that,compared to one-step AD,multi-step AD achieves better performance in long-distance scenarios and can tolerate a higher quantum bit error rate.Specifically,when the difference between the communication distances from Alice and Bob to Charlie is 25 km,50 km and 75 km,and the corresponding transmission distance exceeds 523 km,512 km and 496 km,respectively,the secret key rate achieved by multi-step AD surpasses that of one-step AD.Our findings indicate that the proposed method can effectively promote the application of MP-QKD in scenarios with high loss and high error rate. 展开更多
关键词 mode-pairing quantum key distribution multi-step advantage distillation secret key rate
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Adaptive Multi-Step Evaluation Design With Stability Guarantee for Discrete-Time Optimal Learning Control 认领 引用 被引量：12
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作者 Ding Wang Jiangyu Wang +2 位作者 Mingming Zhao Peng Xin Junfei Qiao 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第9期1797-1809,共13页
This paper is concerned with a novel integrated multi-step heuristic dynamic programming(MsHDP)algorithm for solving optimal control problems.It is shown that,initialized by the zero cost function,MsHDP can converge t... This paper is concerned with a novel integrated multi-step heuristic dynamic programming(MsHDP)algorithm for solving optimal control problems.It is shown that,initialized by the zero cost function,MsHDP can converge to the optimal solution of the Hamilton-Jacobi-Bellman(HJB)equation.Then,the stability of the system is analyzed using control policies generated by MsHDP.Also,a general stability criterion is designed to determine the admissibility of the current control policy.That is,the criterion is applicable not only to traditional value iteration and policy iteration but also to MsHDP.Further,based on the convergence and the stability criterion,the integrated MsHDP algorithm using immature control policies is developed to accelerate learning efficiency greatly.Besides,actor-critic is utilized to implement the integrated MsHDP scheme,where neural networks are used to evaluate and improve the iterative policy as the parameter architecture.Finally,two simulation examples are given to demonstrate that the learning effectiveness of the integrated MsHDP scheme surpasses those of other fixed or integrated methods. 展开更多
关键词 Adaptive critic artificial neural networks Hamilton-Jacobi-Bellman(HJB)equation multi-step heuristic dynamic programming multi-step reinforcement learning optimal control
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Attention-based spatio-temporal graph convolutional network considering external factors for multi-step traffic flow prediction 认领 引用 被引量：14
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作者 Jihua Ye Shengjun Xue Aiwen Jiang 《Digital Communications and Networks》 SCIE CSCD 2022年第3期343-350,共8页
Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network... Traffic flow prediction is an important part of the intelligent transportation system. Accurate multi-step traffic flow prediction plays an important role in improving the operational efficiency of the traffic network. Since traffic flow data has complex spatio-temporal correlation and non-linearity, existing prediction methods are mainly accomplished through a combination of a Graph Convolutional Network (GCN) and a recurrent neural network. The combination strategy has an excellent performance in traffic prediction tasks. However, multi-step prediction error accumulates with the predicted step size. Some scholars use multiple sampling sequences to achieve more accurate prediction results. But it requires high hardware conditions and multiplied training time. Considering the spatiotemporal correlation of traffic flow and influence of external factors, we propose an Attention Based Spatio-Temporal Graph Convolutional Network considering External Factors (ABSTGCN-EF) for multi-step traffic flow prediction. This model models the traffic flow as diffusion on a digraph and extracts the spatial characteristics of traffic flow through GCN. We add meaningful time-slots attention to the encoder-decoder to form an Attention Encoder Network (AEN) to handle temporal correlation. The attention vector is used as a competitive choice to draw the correlation between predicted states and historical states. We considered the impact of three external factors (daytime, weekdays, and traffic accident markers) on the traffic flow prediction tasks. Experiments on two public data sets show that it makes sense to consider external factors. The prediction performance of our ABSTGCN-EF model achieves 7.2%–8.7% higher than the state-of-the-art baselines. 展开更多
关键词 Multi-step traffic flow prediction Graph convolutional network External factors Attentional encoder network Spatiotemporal correlation
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A hybrid decomposition-boosting model for short-term multi-step solar radiation forecasting with NARX neural network 认领 引用 被引量：6
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作者 HUANG Jia-hao LIU Hui 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第2期507-526,共20页
Due to global energy depletion,solar energy technology has been widely used in the world.The output power of the solar energy systems is affected by solar radiation.Accurate short-term forecasting of solar radiation c... Due to global energy depletion,solar energy technology has been widely used in the world.The output power of the solar energy systems is affected by solar radiation.Accurate short-term forecasting of solar radiation can ensure the safety of photovoltaic grids and improve the utilization efficiency of the solar energy systems.In the study,a new decomposition-boosting model using artificial intelligence is proposed to realize the solar radiation multi-step prediction.The proposed model includes four parts:signal decomposition(EWT),neural network(NARX),Adaboost and ARIMA.Three real solar radiation datasets from Changde,China were used to validate the efficiency of the proposed model.To verify the robustness of the multi-step prediction model,this experiment compared nine models and made 1,3,and 5 steps ahead predictions for the time series.It is verified that the proposed model has the best performance among all models. 展开更多
关键词 solar radiation forecasting multi-step forecasting smart hybrid model signal decomposition
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Accurate Multi-Site Daily-Ahead Multi-Step PM2.5Concentrations Forecasting Using Space-Shared CNN-LSTM 认领 引用 被引量：6
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作者 Xiaorui Shao Chang Soo Kim 《Computers, Materials & Continua》 SCIE EI 2022年第3期5143-5160,共18页
Accurate multi-step PM2.5(particulate matter with diameters≤2.5 um)concentration prediction is critical for humankinds’health and air populationmanagement because it could provide strong evidence for decisionmaki... Accurate multi-step PM2.5(particulate matter with diameters≤2.5 um)concentration prediction is critical for humankinds’health and air populationmanagement because it could provide strong evidence for decisionmaking.However,it is very challenging due to its randomness and variability.This paper proposed a novel method based on convolutional neural network(CNN)and long-short-term memory(LSTM)with a space-shared mechanism,named space-shared CNN-LSTM(SCNN-LSTM)for multi-site dailyahead multi-step PM2.5forecasting with self-historical series.The proposed SCNN-LSTM contains multi-channel inputs,each channel corresponding to one-site historical PM2.5concentration series.In which,CNN and LSTM are used to extract each site’s rich hidden feature representations in a stack mode.Especially,CNN is to extract the hidden short-time gap PM2.5concentration patterns;LSTM is to mine the hidden features with long-time dependency.Each channel extracted features aremerged as the comprehensive features for future multi-step PM2.5concentration forecasting.Besides,the space-shared mechanism is implemented by multi-loss functions to achieve space information sharing.Therefore,the final features are the fusion of short-time gap,long-time dependency,and space information,which enables forecasting more accurately.To validate the proposed method’s effectiveness,the authors designed,trained,and compared it with various leading methods in terms of RMSE,MAE,MAPE,and R2on four real-word PM2.5data sets in Seoul,South Korea.The massive experiments proved that the proposed method could accurately forecast multi-site multi-step PM2.5concentration only using self-historical PM2.5concentration time series and running once.Specifically,the proposed method obtained averaged RMSE of 8.05,MAE of 5.04,MAPE of 23.96%,and R2of 0.7 for four-site daily ahead 10-hourPM2.5concentration forecasting. 展开更多
关键词 PM2.5forecasting CNN-LSTM air quality management multi-site multi-step forecasting
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Effects of yttrium addition and aging on mechanical properties of AA2024 fabricated through multi-step stir casting 认领 引用 被引量：3
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作者 CH.S.VIDYASAGAR D.B.KARUNAKAR 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第2期288-302,共15页
The effects of yttrium and artificial aging on AA2024 alloy were investigated.The developed samples were further subjected to artificial aging at 190℃for 1-10 h with an interval of 1 h.The metallurgical characterizat... The effects of yttrium and artificial aging on AA2024 alloy were investigated.The developed samples were further subjected to artificial aging at 190℃for 1-10 h with an interval of 1 h.The metallurgical characterization was done by scanning electron microscope and X-ray diffraction.The mechanical characterization like hardness and tensile strength of the samples was done using computerized Vickers hardness testing machine and universal testing machine.The microstructures revealed that addition of yttrium refined theα(Al)matrix and led to the formation of Al-Cu-Y intermetallic in the shape of Chinese script which strengthened the samples.Compared to the base metal,samples with yttrium addition showed better mechanical properties.The sample reinforced with 0.3 wt.%yttrium showed the highest mechanical properties with the hardness of 66 HV,UTS of 223 MPa,YS of 180 MPa,and elongation of 20.9%.The artificially aged samples showed that the peak hardening of all the samples took place within 5 h of aging at 190℃with Al2 Cu precipitation.Aging changed the intermetallic from Chinese script to the fibrous form.The optimum amount of yttrium addition to AA2024 was found to be 0.3 wt.%. 展开更多
关键词 yttrium artificial aging mechanical properties multi-step stir casting precipitation microstructure characterization
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Adaptive multi-step piecewise interpolation reproducing kernel method for solving the nonlinear time-fractional partial differential equation arising from financial economics 认领 引用 被引量：2
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作者 杜明婧 孙宝军 凯歌 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期53-57,共5页
This paper is aimed at solving the nonlinear time-fractional partial differential equation with two small parameters arising from option pricing model in financial economics.The traditional reproducing kernel(RK)metho... This paper is aimed at solving the nonlinear time-fractional partial differential equation with two small parameters arising from option pricing model in financial economics.The traditional reproducing kernel(RK)method which deals with this problem is very troublesome.This paper proposes a new method by adaptive multi-step piecewise interpolation reproducing kernel(AMPIRK)method for the first time.This method has three obvious advantages which are as follows.Firstly,the piecewise number is reduced.Secondly,the calculation accuracy is improved.Finally,the waste time caused by too many fragments is avoided.Then four numerical examples show that this new method has a higher precision and it is a more timesaving numerical method than the others.The research in this paper provides a powerful mathematical tool for solving time-fractional option pricing model which will play an important role in financial economics. 展开更多
关键词 time-fractional partial differential equation adaptive multi-step reproducing kernel method method numerical solution
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Chaotic time series multi-step direct prediction with partial least squares regression 认领 引用 被引量：2
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作者 Liu Zunxiong Liu Jianhui 《Journal of Systems Engineering and Electronics》 SCIE EI 2007年第3期611-615,共5页
Considering chaotic time series multi-step prediction, multi-step direct prediction model based on partial least squares （PLS） is proposed in this article, where PLS, the method for predicting a set of dependent var... Considering chaotic time series multi-step prediction, multi-step direct prediction model based on partial least squares （PLS） is proposed in this article, where PLS, the method for predicting a set of dependent variables forming a large set of predictors, is used to model the dynamic evolution between the space points and the corresponding future points. The model can eliminate error accumulation with the common single-step local model algorithm~ and refrain from the high multi-collinearity problem in the reconstructed state space with the increase of embedding dimension. Simulation predictions are done on the Mackey-Glass chaotic time series with the model. The satisfying prediction accuracy is obtained and the model efficiency verified. In the experiments, the number of extracted components in PLS is set with cross-validation procedure. 展开更多
关键词 chaotic series prediction multi-step, local model partial least squares.
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Damping of Oblique Ocean Waves by a Vertical Porous Structure Placed on a Multi-step Bottom 认领 引用 被引量：1
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作者 Santu Das Swaroop Nandan Bora 《Journal of Marine Science and Application》 2014年第4期362-376,共15页
Oblique ocean wave damping by a vertical porous structure placed on a multi-step bottom topography is studied with the help of linear water wave theory.Some portion of the oblique wave,incident on the porous structure... Oblique ocean wave damping by a vertical porous structure placed on a multi-step bottom topography is studied with the help of linear water wave theory.Some portion of the oblique wave,incident on the porous structure,gets reflected by the multi-step bottom and the porous structure,and the rest propagates into the water medium following the porous structure.Two cases are considered:first a solid vertical wall placed at a finite distance from the porous structure in the water medium following the porous structure and then a special case of an unbounded water medium following the porous structure.In both cases,boundary value problems are set up in three different media,the first medium being water,the second medium being the porous structure consisting ofp vertical regions-one above each step and the third medium being water again.By using the matching conditions along the virtualvertical boundaries,a system of linear equations is deduced.The behavior of the reflection coefficient and the dimensionless amplitude of the transmitted progressive wave due to different relevant parameters are studied.Energy loss due to the propagation of oblique water wave through the porous structure is also carried out.The effects of various parameters,such as number of evanescent modes,porosity,friction factor,structure width,number of steps and angle of incidence,on the reflection coefficient and the dimensionless amplitude of the transmitted wave are studied graphically for both cases.Number of evanescent modes merely affects the scattering phenomenon.But higher values of porosity show relatively lower reflection than that for lower porosity.Oscillation in the reflection coefficient is observed for lower values of friction factor but it disappears with an increase in the value of friction factor.Amplitude of the transmitted progressive wave is independent of the porosity of the structure.But lower value of friction factor causes higher transmission.The investigation is then carried out for the second case,i.e.,when the wall is absent.The significant difference between the two cases considered here is that the reflection due to a thin porous structure is very high when the solid wall exists as compared to the case when no wall is present.Energy loss due to different porosity,friction factor,structure width and angle of incidence is also examined.Validity of our model is ascertained by matching it with an available one. 展开更多
关键词 porous structure oblique wave reflection matching condition multi-step bottom friction factor energy loss
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Multi-step Reaction Route Developed for Improving Crystallinity of Boron Nitride Nanoparticles 认领 引用
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作者 TAN Miao LIAN Gang +3 位作者 ZHANG Xiao ZHANG Shun-jie CUI De-liang WANG Qi-long 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第3期387-390,共4页
A multi-step reaction route was developed to synthesize boron nitride（BN） nanoparticles via the reactionbetween NaN3 and BC13 in a benzene-thermal solution. By means of this route, the crystallinity of BN nanopartic... A multi-step reaction route was developed to synthesize boron nitride（BN） nanoparticles via the reactionbetween NaN3 and BC13 in a benzene-thermal solution. By means of this route, the crystallinity of BN nanoparticleswas improved via increasing the reaction steps. Meanwhile, a phase transformation from hexagonal BN（hBN） or tur-bostratic BN（tBN） to cubic BN（cBN） occurred, resulting in the increase of cBN content. Moreover, the content ofcBN also slightly increased when the temperature was elevated from 265 ℃ to 280 ℃. 展开更多
关键词 Boron nitride Multi-step reaction route Benzene-thermal synthesis Phase transformation
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Bending Properties of GCr15 Steel Guide Rail under the Multi-step Loading 认领 引用
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作者 LU Hong LING He +2 位作者 JUNG Jae-Youn ZHANG Xiao GUO Changqiao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第4期561-564,共4页
To analyze the bending properties of GCr15 steel guide rail based on the elastic-plastic theory,the novel bending loading method consisting of multi-step loading and corresponding unloading was applied in three specim... To analyze the bending properties of GCr15 steel guide rail based on the elastic-plastic theory,the novel bending loading method consisting of multi-step loading and corresponding unloading was applied in three specimens with different cross section shape and different heat treatment condition.According to the experimental results,using numerical calculation software program and the numerical simulation with finite element analysis(FEA),the relationships among the maximal load and displacement on cross section shape with each step bend loading,the loading stroke with the heat treatment condition,and the loading stroke with cross section shape were gained,and also those curves were discussed qualitatively.Finally,the contrast results between the numerical simulation and experiment were carried out to study the influence about the multi-step loading on specimen.It is put forward that enlightenment for the straightening stroke in the precision linear guide rail manufacture process. 展开更多
关键词 bending properties guide rail multi-step loading stress-strain curve elastic modules
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Lagrangian simulation of multi-step and rate-limited chemical reactions in multi-dimensional porous media 认领 引用
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作者 Bing-qing Lu Yong Zhang +1 位作者 Hong-guang Sun Chun-miao Zheng 《Water Science and Engineering》 EI CAS CSCD 2018年第2期101-113,共13页
Management of groundwater resources and remediation of groundwater pollution require reliable quantification of contaminant dynamics in natural aquifers, which can involve complex chemical dynamics and challenge tradi... Management of groundwater resources and remediation of groundwater pollution require reliable quantification of contaminant dynamics in natural aquifers, which can involve complex chemical dynamics and challenge traditional modeling approaches. The kinetics of chemical reactions in groundwater are well known to be controlled by medium heterogeneity and reactant mixing, motivating the development of particle-based Lagrangian approaches. Previous Lagrangian solvers have been limited to fundamental bimolecular reactions in typically one-dimensional porous media. In contrast to other existing studies, this study developed a fully Lagrangian framework, which was used to simulate diffusion-controlled, multi-step reactions in one-, two-, and three-dimensional porous media. The interaction radius of a reactant molecule, which controls the probability of reaction, was derived by the agent-based approach for both irreversible and reversible reactions. A flexible particle tracking scheme was then developed to build trajectories for particles undergoing mixing-limited, multi-step reactions. The simulated particle dynamics were checked against the kinetics for diffusion-controlled reactions and thermodynamic wellmixed reactions in one-and two-dimensional domains. Applicability of the novel simulator was further tested by(1) simulating precipitation of calcium carbonate minerals in a two-dimensional medium, and(2) quantifying multi-step chemical reactions observed in the laboratory. The flexibility of the Lagrangian simulator allows further refinement to capture complex transport affecting chemical mixing and hence reactions. 展开更多
关键词 Lagrangian framework Chemical reaction Diffusion-limited process Multi-step reactions Interaction radius
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Influence of a multi-step process on the thickness reduction error of sheet metal in a flexible rolling process 认领 引用
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作者 Yi Li Ming-zhe Li Kai Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2019年第1期76-85,共10页
Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the probl... Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the problem of bending deformation error caused by insufficient thickness reduction. Under the condition of different rolling reductions with the same sheet thickness and the same thickness reduction with different sheet thicknesses, the thickness reduction error of sheet metal is analyzed. In addition, the bending deformation of sheet metal under the same conditions is discussed and the influence of the multi-step forming process on the thickness reduction error is studied. The results show that, under the condition of the same sheet thickness, the thickness reduction error increases with increasing rolling reduction because of an increase in work hardening. As rolling reduction increases, the longitudinal bending deformation decreases because of the decrease of the maximum thickness difference. Under the condition with the same thickness reduction, the thickness reduction error increases because of the decrease of the rolling force with increasing sheet thickness. As the sheet thickness increases, the longitudinal bending deformation increases because of the increase in the maximum thickness difference. A larger bending deformation is divided into a number of small bending deformations in a multi-step forming process, avoiding a sharp increase in the degree of work hardening; the thickness reduction error is effectively reduced in the multi-step forming process. Numerical simulation results agree with the results of the forming experiments. 展开更多
关键词 flexible rolling convex surface numerical simulation thickness reduction error multi-step forming process
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Chaos control of gear system with elastomeric web based on multi-parameter multi-step method 认领 引用
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作者 刘海霞 江波 +1 位作者 王三民 郭家舜 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第5期23-30,共8页
This paper employs a multi-parameter multi-step chaos control method, which is built up on the OGY method, to stabilize desirable UPOs of a gear system with elastomeric web as a high-dimensional and non-hyperbolic cha... This paper employs a multi-parameter multi-step chaos control method, which is built up on the OGY method, to stabilize desirable UPOs of a gear system with elastomeric web as a high-dimensional and non-hyperbolic chaotic system, and the analyses are carried out. Three types of relations between components of a certain control parameter combination are defined in a certain control process. Special emphasis is put on the comparison of control efficiencies of the multi-parameter multi-step method and single-parameter multi-step method. The numerical experiments show the ability to switch between different orbits and the method can be a good chaos control alternative since it provides a more effective UPOs stabilization of high-dimensional and non-hyperbolic chaotic systems than the single-parameter chaos control, and according to the relation between components of each parameter combination, the best combination for chaos control in a certain UPO stabilization process are obtained. 展开更多
关键词 chaos control a gear system with elastomeric web multi-parameter multi-step method high-dimensional and non-hyperbolic system
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Banach空间中Mann-Ishikawa迭代和Multi-Step迭代的等价性问题 认领 引用
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作者 吴雪芹 李必文 王双 《数学杂志》 北大核心 2010年第5期905-912,共8页
本文研究了一致光滑Banach空间中迭代算法等价性的问题.利用泛函分析的方法,获得了广义强连接Φ伪压缩算子在具误差的修正的Mann-Ishikawa迭代和具误差的修正的multi-step迭代下收敛等价性的结果,推广了目前的相关结果.
关键词 具误差的修正的Mann-Ishikawa迭代序列 具误差的修正的Multi-step迭代序列 广义强连接Φ伪压缩算子
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