Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In...Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.展开更多
An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly desi...An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.展开更多
Ultrasonic testing(UT)is increasingly combined with machine learning(ML)techniques for intelligently identifying damage.Extracting signifcant features from UT data is essential for efcient defect characterization.More...Ultrasonic testing(UT)is increasingly combined with machine learning(ML)techniques for intelligently identifying damage.Extracting signifcant features from UT data is essential for efcient defect characterization.Moreover,the hidden physics behind ML is unexplained,reducing the generalization capability and versatility of ML methods in UT.In this paper,a generally applicable ML framework based on the model interpretation strategy is proposed to improve the detection accuracy and computational efciency of UT.Firstly,multi-domain features are extracted from the UT signals with signal processing techniques to construct an initial feature space.Subsequently,a feature selection method based on model interpretable strategy(FS-MIS)is innovatively developed by integrating Shapley additive explanation(SHAP),flter method,embedded method and wrapper method.The most efective ML model and the optimal feature subset with better correlation to the target defects are determined self-adaptively.The proposed framework is validated by identifying and locating side-drilled holes(SDHs)with 0.5λcentral distance and different depths.An ultrasonic array probe is adopted to acquire FMC datasets from several aluminum alloy specimens containing two SDHs by experiments.The optimal feature subset selected by FS-MIS is set as the input of the chosen ML model to train and predict the times of arrival(ToAs)of the scattered waves emitted by adjacent SDHs.The experimental results demonstrate that the relative errors of the predicted ToAs are all below 3.67%with an average error of 0.25%,signifcantly improving the time resolution of UT signals.On this basis,the predicted ToAs are assigned to the corresponding original signals for decoupling overlapped pulse-echoes and reconstructing high-resolution FMC datasets.The imaging resolution is enhanced to 0.5λby implementing the total focusing method(TFM).The relative errors of hole depths and central distance are no more than 0.51%and 3.57%,respectively.Finally,the superior performance of the proposed FS-MIS is validated by comparing it with initial feature space and conventional dimensionality reduction techniques.展开更多
Surface cracks are commonly observed in coatings and films.When structures with coatings are subject to stretching,opening mode cracks are likely to form on the surface,which may further lead to other forms of damage,...Surface cracks are commonly observed in coatings and films.When structures with coatings are subject to stretching,opening mode cracks are likely to form on the surface,which may further lead to other forms of damage,such as interfacial delamination and substrate damage.Possible crack forms include cracks extending towards the interface and channeling across the film.In this paper,a two-dimensional numerical model is proposed to obtain the structural strain energy at arbitrary crack lengths for bilayer structures under uniaxial tension.The energy release rate and structural stress intensity factors can be obtained accordingly,and the effects of geometry and material features on fracture characteristics are investigated,with most crack patterns being confirmed as unstable.The proposed model can also facilitate the analysis of the stress distribution in periodic crack patterns of films.The results from the numerical model are compared with those obtained by the finite element method(FEM),and the accuracy of the theoretical results is demonstrated.展开更多
In order to better guide the design of industrial process for purification and recovery of VOCs,temperature swing adsorption(TSA)and temperature vacuum swing adsorption(TVSA)process for VOCs purification and recovery ...In order to better guide the design of industrial process for purification and recovery of VOCs,temperature swing adsorption(TSA)and temperature vacuum swing adsorption(TVSA)process for VOCs purification and recovery were studied systematically with activated carbon adsorbent.The adsorption and desorption behaviors of benzene on activated carbon in above two processes were investigated systematically.Effects of operating parameters on process performances were further analyzed,including as regeneration temperature,purging feed ratio and hot–cold purging ratio.The results showed that the increase of hot–cold purging ratio(HP/CP)could obtain the same regeneration effect as the increase of desorption temperature.Increasing the feed purge ratio without increasing the hot–cold purging ratio is not conducive to bed regeneration,because a large number of cold purge gases cannot utilize the residual heat of temperature wave,thus reducing the desorption effect of the cooling step on the bed.In addition,the vacuum step can enhance the regeneration ability of hot nitrogen to the bed at the same regeneration temperature,making the bed regeneration of TVSA process more thorough.Temperature in the middle and lower part of the bed in TVSA process was higher and the regeneration was more thorough.In conclusion,TVSA has more obvious advantages than TSA in terms of energy consumption,hot or cold purge volume and bed regeneration.展开更多
In the framework of vigorous promotion of low-carbon power system growth as well as economic globalization,multi-resource penetration in active distribution networks has been advancing fiercely.In particular,distribut...In the framework of vigorous promotion of low-carbon power system growth as well as economic globalization,multi-resource penetration in active distribution networks has been advancing fiercely.In particular,distributed generation(DG)based on renewable energy is critical for active distribution network operation enhancement.To comprehensively analyze the accessing impact of DG in distribution networks from various parts,this paper establishes an optimal DG location and sizing planning model based on active power losses,voltage profile,pollution emissions,and the economics of DG costs as well as meteorological conditions.Subsequently,multiobjective particle swarm optimization(MOPSO)is applied to obtain the optimal Pareto front.Besides,for the sake of avoiding the influence of the subjective setting of the weight coefficient,the decisionmethod based on amodified ideal point is applied to execute a Pareto front decision.Finally,simulation tests based on IEEE33 and IEEE69 nodes are designed.The experimental results show thatMOPSO can achieve wider and more uniformPareto front distribution.In the IEEE33 node test system,power loss,and voltage deviation decreased by 52.23%,and 38.89%,respectively,while taking the economy into account.In the IEEE69 test system,the three indexes decreased by 19.67%,and 58.96%,respectively.展开更多
The role of macrophages (MФ) as the first line of host defense is well accepted. These cells play a central role in orchestrating crucial functions during schistosomal infection. Thus, understanding the functional ...The role of macrophages (MФ) as the first line of host defense is well accepted. These cells play a central role in orchestrating crucial functions during schistosomal infection. Thus, understanding the functional diversity of these cells in the process of infection as well as the mechanisms underlying these events is crucial for developing disease control strategies. In this study, we adopted a Mqb polarization recognition system. M1 macrophage was characterized by expressing CD16/32, IL-12 and iNOS. M2 macrophage was characterized by expressing CD206, IL-10 and arg-1. In vivo (mouse peritoneal macrophages of different infection stages were obtained) and in vitro (different S. japonicum antigens were used to stimulate RAW264.7) were characterized by using the above mentioned system. NCA and ACA stimulated RAW264.7 express significantly higher levels of IL-12 while significantly higher levels of IL-10 were detected after soluble egg antigen (SEA) stimulation. The results showed that dramatic changes of antigen in the microenvironment before and after egg production led to macrophage polarization. Furthermore, through TLR blocking experiments, the TLR4 signaling pathway was found to play a role in the process of macrophage polarization toward M1. Our data suggest that macrophage polarization during S. japonicum infection had significant effects on host immune responses to S. japonicum.展开更多
In this paper,a model of activated carbon was established by molecular simulation and the separation performance of N2 and CH4 on activated carbon was studied.In order to evaluate the adsorption selectivity and diffus...In this paper,a model of activated carbon was established by molecular simulation and the separation performance of N2 and CH4 on activated carbon was studied.In order to evaluate the adsorption selectivity and diffusion selectivity of N2 and CH4,Grand Canonical Monte Carlo and molecular dynamic methods were used to obtain equilibrium adsorption isotherms and mean square displacements of N2 and CH4 on activated carbon with different pore sizes.Research results showed that the difference in adsorption isosteric heat of N2 and CH4 at the pore size of 0.46 nm is the largest,which is 5.759 and 7.03 kcal·mol^-1(1 cal=4.184 J),respectively.Activated carbon with pore size of 0.46 nm has the best N2 and CH4 adsorption selectivity,while its diffusion selectivity is not obvious.展开更多
The enrichment of low concentration coalbed methane using adsorption process with activated carbon adsorbent was studied in this work.Adsorption isotherms of methane,nitrogen and carbon dioxide on activated carbon wer...The enrichment of low concentration coalbed methane using adsorption process with activated carbon adsorbent was studied in this work.Adsorption isotherms of methane,nitrogen and carbon dioxide on activated carbon were measured by volumetric method,meanwhile a series of breakthrough tests with single component,binary components and three components feed mixture has been performed for exploring dynamic adsorption behaviors.Moreover,a rigorous mathematical model of adsorption bed containing mass,energy,and momentum conservation equation as well as dualsite Langmuir model with the Linear driving force model for gassolid phase mass transfer has been proposed for numerical modeling and simulation of fixed bed breakthrough process and vacuum pressure swing adsorption process.Furthermore,the lumped mass transfer coefficient of methane,nitrogen and carbon dioxide on activated carbon adsorbent has been determined to be 0.3 s^(-1),1.0 s^(-1) and 0.06 s^(-1) by fitting the breakthrough curves using numerical calculation.Additionally,a six bed VPSA process with twelve step cycle sequence has been proposed and investigated for low concentration coalbed methane enrichment.Results demonstrated that the methane molar fraction in feed mixture ranged from 10%to 50%could be enriched to 32.15%to 88.75%methane in heavy product gas with a methane recovery higher than 83%under the adsorption pressure of 3 bar(1 bar=105 Pa)and desorption pressure of 0.1 bar.Energy consumption of this VPSA process was varied from 0.165 k·W·h·m^(-3) CH_(4)to 0.649 k·W·h·m^(-3) CH_(4).Finally,a dualstage VPSA process has been successfully developed to upgrade a low concentration coalbed methane containing 20%methane to a target product gas with methane purity higher than 90%,meanwhile the total methane recovery was up to 98.71%with a total energy consumption of 0.504 k·W·h·m^(-3)CH_(4).展开更多
A two-stage vacuum pressure swing adsorption(VPSA)process that coupled kinetically controlled and equilibrium controlled separation process with reflux has been investigated for capturing carbon dioxide from dry flue ...A two-stage vacuum pressure swing adsorption(VPSA)process that coupled kinetically controlled and equilibrium controlled separation process with reflux has been investigated for capturing carbon dioxide from dry flue gas(85%N_(2)/15%CO_(2)).In the first enriching stage,carbon molecular sieve(CMS),which shows kinetic selectivity for CO_(2)/N_(2),is adopted as the adsorbent to remove most N_(2)in feed gas,thereby upgrading CO_(2)and significantly reducing the amount for further refinement.The second stage loads zeolite 13X as adsorbent to purify the CO_(2)-rich flow from the first stage for meeting the requirements of National Energy Technology Laboratory.Series of experiments have been conducted for adsorption isotherms measuring and lab-scale experimental validation as well as analysis.The effect of feed composition on the separation performance of the PSA system was studied experimentally and theoretically here.The optimal results achieved 95.1%purity and 92.9%recovery with a high CO_(2)productivity(1.89 mol CO_(2)·h^(-1)·kg^(-1))and an appropriate energy consumption of 1.07 MJ·(kg CO_(2))^(-1).Further analysis has been carried out by simulation for explicating the temperature,pressure,and concentration distribution at cyclic steady state.展开更多
In this work,a six-bed pressure swing adsorption(PSA)process was investigated to produce medical oxygen from air,which uses the combination of six-way rotating distribution valve and PSA and has the main advantage of ...In this work,a six-bed pressure swing adsorption(PSA)process was investigated to produce medical oxygen from air,which uses the combination of six-way rotating distribution valve and PSA and has the main advantage of effectively saving space compared to the traditional two-bed or four-bed PSA process and can obtain greater productivity.The mathematical model of adsorption beds was developed based on the separation mechanism and the interaction among different equipment.Moreover,a pilot-scale device has been constructed to verify the accuracy of mathematical model by experiment.The oxygen product conformed to the medical standard(>93%(vol))with a recovery of over 57%.Some related parameters were also discussed in detail,such as step time,ratio of length to the diameter,flow rate of product.展开更多
In making the gas-solid-liquid phase analysis, based on the collaborative study of the internal and external humidification ratio of desulfurization efficiency, determine the humidifier ratio within 60% to 75%, that c...In making the gas-solid-liquid phase analysis, based on the collaborative study of the internal and external humidification ratio of desulfurization efficiency, determine the humidifier ratio within 60% to 75%, that can make the best balance between the respective merits of a simple tower humidifiers tower humidifier way, optimizing the overall desulfurization reaction, effectively reducing the sticky wall, stick in the desulfurization efficiency and reduce the wall to achieve a balance between the balance, without increasing the sorbent and process water, under the premise can promote the desulfurization reaction, improve the desulfurization sorbent utilization and efficiency, help desulfurization reaction system is stable, efficient and economic operation, the gas-liquid-solid three-phase to achieve better synergy.展开更多
Particle-fluid system is one of the most popular systems in chemical processes.Owing to complex interface structure and high-velocity turbulence,the momentum and mass transfer exhibit nonlinear characteristics,which p...Particle-fluid system is one of the most popular systems in chemical processes.Owing to complex interface structure and high-velocity turbulence,the momentum and mass transfer exhibit nonlinear characteristics,which pose a great challenge for further study and application.To solve this problem,computational mass transfer(CMT)emerged and has been proved to be effective in deeply exploring the mass transfer behavior of particle-fluid systems.First,this paper reviews recent gas-solid numerical studies of turbulence issues from empirical to theoretical,then discusses interphase mass transfer rate models and the interfacial interaction force.Second,the present study particularly reviews researches on mass transfer process of fixed and fluidized regime by CMT,providing reliable analysis of turbulent anisotropy diffusivity as well as multiscale structure and presenting theoretical instruction for the industrial optimization of mass transfer processes in chemical engineering.展开更多
Inherited cardiovascular diseases(CVDs)threaten human health and pose an enormous economic burden worldwide.Genetic alteration is a major risk factor for many CVDs.These disorders are usually controlled by a pair of a...Inherited cardiovascular diseases(CVDs)threaten human health and pose an enormous economic burden worldwide.Genetic alteration is a major risk factor for many CVDs.These disorders are usually controlled by a pair of alleles,affecting offspring according to the Mendelian principle,regardless of isolated primary damage or secondary injury from other syndromes or deficiency.To date,there are hundreds of inherited CVDs.With advances in nextgeneration sequencing(NGS)technologies,rapid and accurate molecular diagnosis of patients with inherited CVDs is clinically practical.Besides,great improvements have been made in recent years,and targeted therapy and assist devices have been used in clinical practice.Yet there is still no totally efficient strategy for dealing with inherited CVDs.Accordingly.展开更多
In recent years,RS and GIS technologies have played an increasingly important role in various aspects of rainfall induced landslide research.In order to systematically understand their application situation,this paper...In recent years,RS and GIS technologies have played an increasingly important role in various aspects of rainfall induced landslide research.In order to systematically understand their application situation,this paper extensively used various visualization analysis technologies for in-depth analysis of 1,161 documents collected by the WOS data platform in the past 27 years by combining quantitative and qualitative methods.Then,this article focuses on sub domain analysis from four aspects:landslide detection and monitoring,prediction models,sensitivity mapping,and risk assessment.The study found that the number of literature in thisfield has steadily increased and is expected to continue to rise.This literature review has attracted widespread attention from the academic community,but it challenging to meet research needs.Frequent and effective cooperationis between countries,institutions,and authors is very beneficial for promoting progress in thisfield.The future development direction is a new intelligent hybrid model that integrates multiple research methods.This study can provide researchers in thisfield with the core research force,hot topic evolution,and future development trends of future rainfall-induced landslides and contribute to landslide prevention and control decision-making and achieving the United Nations’sustainable development goals.展开更多
L-valve is often used as a non-mechanical valve for the circulation of solids in gas-solids fluidized bed(GSFB)due to its advantages in simple construction and easy control.The information on solids circu-lation rate ...L-valve is often used as a non-mechanical valve for the circulation of solids in gas-solids fluidized bed(GSFB)due to its advantages in simple construction and easy control.The information on solids circu-lation rate as well as the hydrodynamics performance of the CFB with L-valve is of great importance for its better control and design.This paper proposes a Eulerian-Eulerian approach based numerical model integrating the computational fluid dynamics(CFD)with turbulent model,the kinetic theory of granular flow(KTGF)and the drag model,thus the solids circulation rate and the local phase velocity as well as solids volume fraction can be predicted simultaneously.With this model,the hydrodynamics perfor-mance of the full loop GSCFB with a L-valve is analyzed in detail.It is found that the drag model affects the simulation significantly and the(energy minimization multiscale)EMMS method shows good per-formance in the full-loop simulation of GSCFB.展开更多
The study of lipid metabolism relies on the characterization of the lipidome,which is quite complex due to the structure variations of the lipid species.New analytical tools have been developed recently for characteri...The study of lipid metabolism relies on the characterization of the lipidome,which is quite complex due to the structure variations of the lipid species.New analytical tools have been developed recently for characterizing fine structures of lipids,with C=C location identification as one of the major improvements.In this study,we studied the lipid metabolism reprograming by analyzing glycerol phospholipid compositions in breast cancer cell lines with structural specification extended to the C=C location level.Inhibition of the lipid desaturase,stearoyl-CoA desaturase 1,increased the proportion of n-10 isomers that are produced via an alternative fatty acid desaturase 2 pathway.However,there were different variations of the ratio of n-9/n-7 isomers in C18:1-containing glycerol phospholipids after stearoyl-CoA desaturase 1 inhibition,showing increased tendency in MCF-7 cells,MDA-MB-468 cells,and BT-474 cells,but decreased tendency in MDA-MB-231 cells.No consistent change of the ratio of n-9/n-7 isomers was observed in SK-BR-3 cells.This type of heterogeneity in reprogrammed lipid metabolism can be rationalized by considering both lipid desaturation and fatty acid oxidation,highlighting the critical roles of comprehensive lipid analysis in both fundamental and biomedical applications.展开更多
Accurate segmentation and detection of rice seedlings is essential for precision agriculture and high-yield cultivation.However,current methods suffer from high computational complexity and poor robustness to differen...Accurate segmentation and detection of rice seedlings is essential for precision agriculture and high-yield cultivation.However,current methods suffer from high computational complexity and poor robustness to different rice varieties and densities.This article proposes 2 Iightweight neural network architectures,LW-Segnet and LW-Unet,for high-precision rice seedling segmentation.The networks adopt an encoder-decoderstructure with hybrid lightweight convolutions and spatial pyramid dilated convolutions,achieving accurate segmentation while reducing model parameters.Multispectral imagery acquired by unmanned aerial vehicle(UAV)was used to train and test the models covering 3 rice varieties and different planting densities.Experimental results demonstrate that the proposed LW-Segnet and LW-Unet models achieve higher F1-scores and intersection over union values for seedling detection and row segmentation across varieties,indicating improved segmentation accuracy.Furthermore,the models exhibit stable performance when handling different varieties and densities,showing strong robustness.In terms of efficiency,the networks have lower graphics processing unit memory usage,complexity,and parameters but faster inference speeds,reflecting higher computational efficiency.In particular,the fast speed of LW-Unet indicates potential for real-time applications.The study presents lightweight yet effective neural network architectures for agricultural tasks.By handling multiple rice varieties and densities with high accuracy,efficiency,and robustness,the models show promise for use in edge devices and UAVs to assist precision farming and crop management.The findings provide valuable insights into designing lightweight deep learning models to tackle complex agricultural problems.展开更多
基金supported by the renewable energy and hydrogen projects in National Key Research and Development Plan of China(2019YFB1505000).
文摘Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.
基金financially supported by the Renewable Energy and Hydrogen Projects in National Key Research & Development Program of China (2019YFB1505000)。
文摘An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.
基金Supported by National Natural Science Foundation of China(Grant Nos.U22B2068,52275520,52075078)National Key Research and Development Program of China(Grant No.2019YFA0709003).
文摘Ultrasonic testing(UT)is increasingly combined with machine learning(ML)techniques for intelligently identifying damage.Extracting signifcant features from UT data is essential for efcient defect characterization.Moreover,the hidden physics behind ML is unexplained,reducing the generalization capability and versatility of ML methods in UT.In this paper,a generally applicable ML framework based on the model interpretation strategy is proposed to improve the detection accuracy and computational efciency of UT.Firstly,multi-domain features are extracted from the UT signals with signal processing techniques to construct an initial feature space.Subsequently,a feature selection method based on model interpretable strategy(FS-MIS)is innovatively developed by integrating Shapley additive explanation(SHAP),flter method,embedded method and wrapper method.The most efective ML model and the optimal feature subset with better correlation to the target defects are determined self-adaptively.The proposed framework is validated by identifying and locating side-drilled holes(SDHs)with 0.5λcentral distance and different depths.An ultrasonic array probe is adopted to acquire FMC datasets from several aluminum alloy specimens containing two SDHs by experiments.The optimal feature subset selected by FS-MIS is set as the input of the chosen ML model to train and predict the times of arrival(ToAs)of the scattered waves emitted by adjacent SDHs.The experimental results demonstrate that the relative errors of the predicted ToAs are all below 3.67%with an average error of 0.25%,signifcantly improving the time resolution of UT signals.On this basis,the predicted ToAs are assigned to the corresponding original signals for decoupling overlapped pulse-echoes and reconstructing high-resolution FMC datasets.The imaging resolution is enhanced to 0.5λby implementing the total focusing method(TFM).The relative errors of hole depths and central distance are no more than 0.51%and 3.57%,respectively.Finally,the superior performance of the proposed FS-MIS is validated by comparing it with initial feature space and conventional dimensionality reduction techniques.
基金Project supported by the National Natural Science Foundation of China(Nos.12172027 and 11572022)。
文摘Surface cracks are commonly observed in coatings and films.When structures with coatings are subject to stretching,opening mode cracks are likely to form on the surface,which may further lead to other forms of damage,such as interfacial delamination and substrate damage.Possible crack forms include cracks extending towards the interface and channeling across the film.In this paper,a two-dimensional numerical model is proposed to obtain the structural strain energy at arbitrary crack lengths for bilayer structures under uniaxial tension.The energy release rate and structural stress intensity factors can be obtained accordingly,and the effects of geometry and material features on fracture characteristics are investigated,with most crack patterns being confirmed as unstable.The proposed model can also facilitate the analysis of the stress distribution in periodic crack patterns of films.The results from the numerical model are compared with those obtained by the finite element method(FEM),and the accuracy of the theoretical results is demonstrated.
基金Projects in National Key Research and Development Plan of China(2019YFB1505002).
文摘In order to better guide the design of industrial process for purification and recovery of VOCs,temperature swing adsorption(TSA)and temperature vacuum swing adsorption(TVSA)process for VOCs purification and recovery were studied systematically with activated carbon adsorbent.The adsorption and desorption behaviors of benzene on activated carbon in above two processes were investigated systematically.Effects of operating parameters on process performances were further analyzed,including as regeneration temperature,purging feed ratio and hot–cold purging ratio.The results showed that the increase of hot–cold purging ratio(HP/CP)could obtain the same regeneration effect as the increase of desorption temperature.Increasing the feed purge ratio without increasing the hot–cold purging ratio is not conducive to bed regeneration,because a large number of cold purge gases cannot utilize the residual heat of temperature wave,thus reducing the desorption effect of the cooling step on the bed.In addition,the vacuum step can enhance the regeneration ability of hot nitrogen to the bed at the same regeneration temperature,making the bed regeneration of TVSA process more thorough.Temperature in the middle and lower part of the bed in TVSA process was higher and the regeneration was more thorough.In conclusion,TVSA has more obvious advantages than TSA in terms of energy consumption,hot or cold purge volume and bed regeneration.
基金The authors gratefully acknowledge the support of the Enhancement Strategy of Multi-Type Energy Integration of Active Distribution Network(YNKJXM20220113).
文摘In the framework of vigorous promotion of low-carbon power system growth as well as economic globalization,multi-resource penetration in active distribution networks has been advancing fiercely.In particular,distributed generation(DG)based on renewable energy is critical for active distribution network operation enhancement.To comprehensively analyze the accessing impact of DG in distribution networks from various parts,this paper establishes an optimal DG location and sizing planning model based on active power losses,voltage profile,pollution emissions,and the economics of DG costs as well as meteorological conditions.Subsequently,multiobjective particle swarm optimization(MOPSO)is applied to obtain the optimal Pareto front.Besides,for the sake of avoiding the influence of the subjective setting of the weight coefficient,the decisionmethod based on amodified ideal point is applied to execute a Pareto front decision.Finally,simulation tests based on IEEE33 and IEEE69 nodes are designed.The experimental results show thatMOPSO can achieve wider and more uniformPareto front distribution.In the IEEE33 node test system,power loss,and voltage deviation decreased by 52.23%,and 38.89%,respectively,while taking the economy into account.In the IEEE69 test system,the three indexes decreased by 19.67%,and 58.96%,respectively.
文摘The role of macrophages (MФ) as the first line of host defense is well accepted. These cells play a central role in orchestrating crucial functions during schistosomal infection. Thus, understanding the functional diversity of these cells in the process of infection as well as the mechanisms underlying these events is crucial for developing disease control strategies. In this study, we adopted a Mqb polarization recognition system. M1 macrophage was characterized by expressing CD16/32, IL-12 and iNOS. M2 macrophage was characterized by expressing CD206, IL-10 and arg-1. In vivo (mouse peritoneal macrophages of different infection stages were obtained) and in vitro (different S. japonicum antigens were used to stimulate RAW264.7) were characterized by using the above mentioned system. NCA and ACA stimulated RAW264.7 express significantly higher levels of IL-12 while significantly higher levels of IL-10 were detected after soluble egg antigen (SEA) stimulation. The results showed that dramatic changes of antigen in the microenvironment before and after egg production led to macrophage polarization. Furthermore, through TLR blocking experiments, the TLR4 signaling pathway was found to play a role in the process of macrophage polarization toward M1. Our data suggest that macrophage polarization during S. japonicum infection had significant effects on host immune responses to S. japonicum.
基金part of the project supported by the Shanxi Coal-bed Methane Joint Research Fund(No.2015012004)。
文摘In this paper,a model of activated carbon was established by molecular simulation and the separation performance of N2 and CH4 on activated carbon was studied.In order to evaluate the adsorption selectivity and diffusion selectivity of N2 and CH4,Grand Canonical Monte Carlo and molecular dynamic methods were used to obtain equilibrium adsorption isotherms and mean square displacements of N2 and CH4 on activated carbon with different pore sizes.Research results showed that the difference in adsorption isosteric heat of N2 and CH4 at the pore size of 0.46 nm is the largest,which is 5.759 and 7.03 kcal·mol^-1(1 cal=4.184 J),respectively.Activated carbon with pore size of 0.46 nm has the best N2 and CH4 adsorption selectivity,while its diffusion selectivity is not obvious.
文摘The enrichment of low concentration coalbed methane using adsorption process with activated carbon adsorbent was studied in this work.Adsorption isotherms of methane,nitrogen and carbon dioxide on activated carbon were measured by volumetric method,meanwhile a series of breakthrough tests with single component,binary components and three components feed mixture has been performed for exploring dynamic adsorption behaviors.Moreover,a rigorous mathematical model of adsorption bed containing mass,energy,and momentum conservation equation as well as dualsite Langmuir model with the Linear driving force model for gassolid phase mass transfer has been proposed for numerical modeling and simulation of fixed bed breakthrough process and vacuum pressure swing adsorption process.Furthermore,the lumped mass transfer coefficient of methane,nitrogen and carbon dioxide on activated carbon adsorbent has been determined to be 0.3 s^(-1),1.0 s^(-1) and 0.06 s^(-1) by fitting the breakthrough curves using numerical calculation.Additionally,a six bed VPSA process with twelve step cycle sequence has been proposed and investigated for low concentration coalbed methane enrichment.Results demonstrated that the methane molar fraction in feed mixture ranged from 10%to 50%could be enriched to 32.15%to 88.75%methane in heavy product gas with a methane recovery higher than 83%under the adsorption pressure of 3 bar(1 bar=105 Pa)and desorption pressure of 0.1 bar.Energy consumption of this VPSA process was varied from 0.165 k·W·h·m^(-3) CH_(4)to 0.649 k·W·h·m^(-3) CH_(4).Finally,a dualstage VPSA process has been successfully developed to upgrade a low concentration coalbed methane containing 20%methane to a target product gas with methane purity higher than 90%,meanwhile the total methane recovery was up to 98.71%with a total energy consumption of 0.504 k·W·h·m^(-3)CH_(4).
基金financially supported by the Renewable Energy and Hydrogen Projects National Key Research&Development Program of China(2019YFB1505000)。
文摘A two-stage vacuum pressure swing adsorption(VPSA)process that coupled kinetically controlled and equilibrium controlled separation process with reflux has been investigated for capturing carbon dioxide from dry flue gas(85%N_(2)/15%CO_(2)).In the first enriching stage,carbon molecular sieve(CMS),which shows kinetic selectivity for CO_(2)/N_(2),is adopted as the adsorbent to remove most N_(2)in feed gas,thereby upgrading CO_(2)and significantly reducing the amount for further refinement.The second stage loads zeolite 13X as adsorbent to purify the CO_(2)-rich flow from the first stage for meeting the requirements of National Energy Technology Laboratory.Series of experiments have been conducted for adsorption isotherms measuring and lab-scale experimental validation as well as analysis.The effect of feed composition on the separation performance of the PSA system was studied experimentally and theoretically here.The optimal results achieved 95.1%purity and 92.9%recovery with a high CO_(2)productivity(1.89 mol CO_(2)·h^(-1)·kg^(-1))and an appropriate energy consumption of 1.07 MJ·(kg CO_(2))^(-1).Further analysis has been carried out by simulation for explicating the temperature,pressure,and concentration distribution at cyclic steady state.
基金supported by Major military logistics research pro-jects(AWS13Z006)National Key Research and Development program of China(2017YFC0806404).
文摘In this work,a six-bed pressure swing adsorption(PSA)process was investigated to produce medical oxygen from air,which uses the combination of six-way rotating distribution valve and PSA and has the main advantage of effectively saving space compared to the traditional two-bed or four-bed PSA process and can obtain greater productivity.The mathematical model of adsorption beds was developed based on the separation mechanism and the interaction among different equipment.Moreover,a pilot-scale device has been constructed to verify the accuracy of mathematical model by experiment.The oxygen product conformed to the medical standard(>93%(vol))with a recovery of over 57%.Some related parameters were also discussed in detail,such as step time,ratio of length to the diameter,flow rate of product.
文摘In making the gas-solid-liquid phase analysis, based on the collaborative study of the internal and external humidification ratio of desulfurization efficiency, determine the humidifier ratio within 60% to 75%, that can make the best balance between the respective merits of a simple tower humidifiers tower humidifier way, optimizing the overall desulfurization reaction, effectively reducing the sticky wall, stick in the desulfurization efficiency and reduce the wall to achieve a balance between the balance, without increasing the sorbent and process water, under the premise can promote the desulfurization reaction, improve the desulfurization sorbent utilization and efficiency, help desulfurization reaction system is stable, efficient and economic operation, the gas-liquid-solid three-phase to achieve better synergy.
基金the NSFC Project(grant No.22078230)the State Key Laboratory of Heavy Oil Processing(grant No.SKLHOP202202008)the National Key Researchh and Development Program ofC hina(granNt o.2018YFE0111100).
文摘Particle-fluid system is one of the most popular systems in chemical processes.Owing to complex interface structure and high-velocity turbulence,the momentum and mass transfer exhibit nonlinear characteristics,which pose a great challenge for further study and application.To solve this problem,computational mass transfer(CMT)emerged and has been proved to be effective in deeply exploring the mass transfer behavior of particle-fluid systems.First,this paper reviews recent gas-solid numerical studies of turbulence issues from empirical to theoretical,then discusses interphase mass transfer rate models and the interfacial interaction force.Second,the present study particularly reviews researches on mass transfer process of fixed and fluidized regime by CMT,providing reliable analysis of turbulent anisotropy diffusivity as well as multiscale structure and presenting theoretical instruction for the industrial optimization of mass transfer processes in chemical engineering.
基金Key R&D Program of Sichuan Province of China(No.2021YFQ0061)Science and Technology Department of Sichuan Province(No.2022ZYD0067 and MSGC20230024)+2 种基金Natural Science Foundation of China(Nos.82070324,82001496,and 82270249)Project of Chengdu Science and Technology Bureau(No.2021-YF05-02110-SN)China Postdoctoral Science Foundation(Nos.2020M680149 and 2020T130087ZX)
文摘Inherited cardiovascular diseases(CVDs)threaten human health and pose an enormous economic burden worldwide.Genetic alteration is a major risk factor for many CVDs.These disorders are usually controlled by a pair of alleles,affecting offspring according to the Mendelian principle,regardless of isolated primary damage or secondary injury from other syndromes or deficiency.To date,there are hundreds of inherited CVDs.With advances in nextgeneration sequencing(NGS)technologies,rapid and accurate molecular diagnosis of patients with inherited CVDs is clinically practical.Besides,great improvements have been made in recent years,and targeted therapy and assist devices have been used in clinical practice.Yet there is still no totally efficient strategy for dealing with inherited CVDs.Accordingly.
基金supported by the National Key R&D Program of China(2019YFC1510700)the Sichuan Science and Technology Program(2023Y FS0380,2023YFS0377,2023NSFSC1989,2022YFS0539).
文摘In recent years,RS and GIS technologies have played an increasingly important role in various aspects of rainfall induced landslide research.In order to systematically understand their application situation,this paper extensively used various visualization analysis technologies for in-depth analysis of 1,161 documents collected by the WOS data platform in the past 27 years by combining quantitative and qualitative methods.Then,this article focuses on sub domain analysis from four aspects:landslide detection and monitoring,prediction models,sensitivity mapping,and risk assessment.The study found that the number of literature in thisfield has steadily increased and is expected to continue to rise.This literature review has attracted widespread attention from the academic community,but it challenging to meet research needs.Frequent and effective cooperationis between countries,institutions,and authors is very beneficial for promoting progress in thisfield.The future development direction is a new intelligent hybrid model that integrates multiple research methods.This study can provide researchers in thisfield with the core research force,hot topic evolution,and future development trends of future rainfall-induced landslides and contribute to landslide prevention and control decision-making and achieving the United Nations’sustainable development goals.
基金support by the National Key Research and Development Program of China(grant No.2018YFE0111100)the National Nature Science Foundation of China(grant No.22078230)the Open Foundation of State Key Laboratory of Chemical Engineering(grant No.SKL-ChE-21B07).
文摘L-valve is often used as a non-mechanical valve for the circulation of solids in gas-solids fluidized bed(GSFB)due to its advantages in simple construction and easy control.The information on solids circu-lation rate as well as the hydrodynamics performance of the CFB with L-valve is of great importance for its better control and design.This paper proposes a Eulerian-Eulerian approach based numerical model integrating the computational fluid dynamics(CFD)with turbulent model,the kinetic theory of granular flow(KTGF)and the drag model,thus the solids circulation rate and the local phase velocity as well as solids volume fraction can be predicted simultaneously.With this model,the hydrodynamics perfor-mance of the full loop GSCFB with a L-valve is analyzed in detail.It is found that the drag model affects the simulation significantly and the(energy minimization multiscale)EMMS method shows good per-formance in the full-loop simulation of GSCFB.
基金This research is supported by the National Natural Science Foundation of China(Projects 21934003 and 21974077)the Natural Science Foundation of Hubei Provincial Department of Education(2019CFB429).
文摘The study of lipid metabolism relies on the characterization of the lipidome,which is quite complex due to the structure variations of the lipid species.New analytical tools have been developed recently for characterizing fine structures of lipids,with C=C location identification as one of the major improvements.In this study,we studied the lipid metabolism reprograming by analyzing glycerol phospholipid compositions in breast cancer cell lines with structural specification extended to the C=C location level.Inhibition of the lipid desaturase,stearoyl-CoA desaturase 1,increased the proportion of n-10 isomers that are produced via an alternative fatty acid desaturase 2 pathway.However,there were different variations of the ratio of n-9/n-7 isomers in C18:1-containing glycerol phospholipids after stearoyl-CoA desaturase 1 inhibition,showing increased tendency in MCF-7 cells,MDA-MB-468 cells,and BT-474 cells,but decreased tendency in MDA-MB-231 cells.No consistent change of the ratio of n-9/n-7 isomers was observed in SK-BR-3 cells.This type of heterogeneity in reprogrammed lipid metabolism can be rationalized by considering both lipid desaturation and fatty acid oxidation,highlighting the critical roles of comprehensive lipid analysis in both fundamental and biomedical applications.
基金supported by the Heilongjiang Provincial Key Research and Development Program(2022ZX05B05)the Heilongjiang Provincial Postdoctoral Science Foundation(LBH-Z22090)
文摘Accurate segmentation and detection of rice seedlings is essential for precision agriculture and high-yield cultivation.However,current methods suffer from high computational complexity and poor robustness to different rice varieties and densities.This article proposes 2 Iightweight neural network architectures,LW-Segnet and LW-Unet,for high-precision rice seedling segmentation.The networks adopt an encoder-decoderstructure with hybrid lightweight convolutions and spatial pyramid dilated convolutions,achieving accurate segmentation while reducing model parameters.Multispectral imagery acquired by unmanned aerial vehicle(UAV)was used to train and test the models covering 3 rice varieties and different planting densities.Experimental results demonstrate that the proposed LW-Segnet and LW-Unet models achieve higher F1-scores and intersection over union values for seedling detection and row segmentation across varieties,indicating improved segmentation accuracy.Furthermore,the models exhibit stable performance when handling different varieties and densities,showing strong robustness.In terms of efficiency,the networks have lower graphics processing unit memory usage,complexity,and parameters but faster inference speeds,reflecting higher computational efficiency.In particular,the fast speed of LW-Unet indicates potential for real-time applications.The study presents lightweight yet effective neural network architectures for agricultural tasks.By handling multiple rice varieties and densities with high accuracy,efficiency,and robustness,the models show promise for use in edge devices and UAVs to assist precision farming and crop management.The findings provide valuable insights into designing lightweight deep learning models to tackle complex agricultural problems.