In this work,several key scaling laws of the quasi-static magnetic compression of field reversed configuration(FRC)plasma(Spencer et al 1983 Phys.Fluids 261564)are amended from a series of two-dimensional FRC MHD equi...In this work,several key scaling laws of the quasi-static magnetic compression of field reversed configuration(FRC)plasma(Spencer et al 1983 Phys.Fluids 261564)are amended from a series of two-dimensional FRC MHD equilibriums numerically obtained using the Grad–Shafranov equation solver NIMEQ.Based on the new scaling for the elongation and the magnetic fields at the separatrix and the wall,the empirically stable limits for the compression ratio,the fusion gain,and the neutron yield are evaluated,which may serve as a more accurate estimate for the upper ceiling of performance from the magnetic compression of FRC plasma as a potential fusion energy as well as neutron source devices.展开更多
The identification of magnetohydrodynamic(MHD)modes is a crucial issue in the control of magnetically confined plasmas.This paper proposes a novel method for identifying the evolution of MHD modes from a signal with a...The identification of magnetohydrodynamic(MHD)modes is a crucial issue in the control of magnetically confined plasmas.This paper proposes a novel method for identifying the evolution of MHD modes from a signal with a low signal-to-noise ratio.The proposed method generates a weighted directed graph from the time-frequency spectrum and calculates the evolution of the mode frequency by solving the shortest path.This method addresses the limitations posed by the lack of data channels and the disturbance of noise in the estimation of mode frequency and yields much better results compared to traditional methods.It is demonstrated that,using this method,the evolution of an unlocked tearing mode was more accurately calculated on the J-TEXT tokamak.This method remains feasible even with a low signal-to-noise ratio of 0.5,as shown by its uncertainty.Furthermore,with appropriate parameters,this method can be applied to not only signals with MHD modes,but also to general signals with continuous modes.展开更多
Earth-abundant copper-tin(CuSn)electrocatalysts are potential candidates for cost-effective and sustainable production of CO from electrochemical carbon dioxide reduction(eCO_(2)R).However,the requirement of highoverp...Earth-abundant copper-tin(CuSn)electrocatalysts are potential candidates for cost-effective and sustainable production of CO from electrochemical carbon dioxide reduction(eCO_(2)R).However,the requirement of highoverpotential for obtaining reasonable current,low Faradaic efficiencies(FE)and low intrinsic catalytic activities require the optimisation of the CuSn nanoarchitecture for the further advancement in the field.In the current work,we have optimised Sn loading on Cu gas diffusion electrodes(GDEs)by electrochemical spontaneous precipitation.Samples with various Sn loadings were tested in a three-chamber GDE reactor to evaluate their CO_(2)reduction performances.The best performance of 92%CO Faradaic efficiency at a cathodic current density of 120 mA cm^(-2)was obtained from the 20 min Sn deposited Cu_(2)O sample operated at-1.13 V vs.RHE.The electrocatalyst had~13%surface coverage of Sn on Cu GDE surface,and had Sn in oxide form and copper in metallic form.The catalyst also showed stable performance and was operable for>3 h under chronoamperometric conditions.The surface of the GDE reduces from Cu2O to Cu during eCO_(2)R and goes further reconstruction during the eCO_(2)R.This study demonstrates the potential of Cu-Sn for selective CO production at high current densities.展开更多
Numerous studies have shown that cell replacement therapy can replenish lost cells and rebuild neural circuitry in animal models of Parkinson’s disease.Transplantation of midbrain dopaminergic progenitor cells is a p...Numerous studies have shown that cell replacement therapy can replenish lost cells and rebuild neural circuitry in animal models of Parkinson’s disease.Transplantation of midbrain dopaminergic progenitor cells is a promising treatment for Parkinson’s disease.However,transplanted cells can be injured by mechanical damage during handling and by changes in the transplantation niche.Here,we developed a one-step biomanufacturing platform that uses small-aperture gelatin microcarriers to produce beads carrying midbrain dopaminergic progenitor cells.These beads allow midbrain dopaminergic progenitor cell differentiation and cryopreservation without digestion,effectively maintaining axonal integrity in vitro.Importantly,midbrain dopaminergic progenitor cell bead grafts showed increased survival and only mild immunoreactivity in vivo compared with suspended midbrain dopaminergic progenitor cell grafts.Overall,our findings show that these midbrain dopaminergic progenitor cell beads enhance the effectiveness of neuronal cell transplantation.展开更多
Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational...Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems.展开更多
A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the rat...A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel depth.The impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output capability.The results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel cell.An increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.展开更多
In order to effectively implement DPF(Diesel Particulate Filters)regeneration control,thermal management of exhaust products before and inside Diesel Oxidation Catalyst(DOC)is necessary.In the present study,the Influe...In order to effectively implement DPF(Diesel Particulate Filters)regeneration control,thermal management of exhaust products before and inside Diesel Oxidation Catalyst(DOC)is necessary.In the present study,the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests.The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC;in particular,with intake throttle valve opening at 20%,temperature before DOC can be increased by about 170℃ with respect to the full opening.An increase in the late post injection quantity can produce a significant rise of the temperature inside DOC,however its impact on the exhaust temperature before DOC is relatively limited.As the late post injection quantity increases,Hydrocarbon(HC)emissions also grow;in the present work it is shown that with a proper injection quantity,a considerable temperature increase inside the DOC can be obtained with relatively low HC emission.More specifically,with the intake throttle valve at 30%and DOC reaching ignition temperature as the late post injection quantity is increased,the exhaust temperature after DOC can be made larger than 550℃,adequate for DPF active regeneration.展开更多
Although occupational therapy for substance abuse,as a field in psychiatric rehabilitation,has been implemented for over half a century,it still seems underdeveloped.This area of rehabilitation aims to enhance the qua...Although occupational therapy for substance abuse,as a field in psychiatric rehabilitation,has been implemented for over half a century,it still seems underdeveloped.This area of rehabilitation aims to enhance the quality of life of substance abuse rehabilitants and prevent them from relapse.1 It can be achieved by enabling them to identify their meaningful occupations and occupational roles,and supporting them to re-engage in the occupations that they value,which would help empower them to overcome abuse.12 The interventions around the world include brief intervention,motivational strategy,cognitive behavioural therapy.展开更多
Experiments on subcooled flow boiling have been conducted using water in a rectangular flow channel.Similar to the coolant channel in internal combustion engines(IC engines),the flow channel in this experiment was asy...Experiments on subcooled flow boiling have been conducted using water in a rectangular flow channel.Similar to the coolant channel in internal combustion engines(IC engines),the flow channel in this experiment was asymmetrically heated.Bubble images were captured using a high speed camera from the side view of the channel.The experimental conditions in terms of bulk temperature,bulk velocity,pressure and heat flux ranged from 65°C–75°C,0.25 m/s–0.75 m/s,1–1.7 bar and 490 kW/m2–700 kW/m2,respectively.On the basis of these tests,a statistical analysis of the bubble size has been conducted considering a population of 1400 samples.It has been found that the mean Sauter bubble diameter increases with the decrease of subcooling,bulk velocity,pressure and increased heat flux.A modified correlation has been finally proposed to predict the mean Sauter bubble diameter under subcooled flow boiling conditions upstream of the onset of significant void,which shows good accuracy with the experimental results.展开更多
Objective:To evaluate the clinical efficacy of warming acupuncture combined with joint mobilization for the treatment of scapulohumeral periarthritis.Methods:A search for published randomized controlled trials(RCT)inv...Objective:To evaluate the clinical efficacy of warming acupuncture combined with joint mobilization for the treatment of scapulohumeral periarthritis.Methods:A search for published randomized controlled trials(RCT)investigating warming acupuncture combined with joint mobilization for the treatment of scapulohumeral periarthritis was performed using the Cochrane Library,PubMed,Embase,and Web of Science databases.According to requirements of the Cochrane systematic review,all evaluations of RCT investigating warming acupuncture with joint mobilization in the treatment of scapulohumeral periarthritis were performed via method quality assessment,data extraction,and data analysis.Revman 5.3 and Stata 12.0 statistical software were used for the meta-analysis,and the trial sequential analysis(TSA)software estimated the required information size for each outcome.Results:A total of 14 articles were retrieved for meta-analysis,which included 551 cases in the treatment group and 539 cases in the control group.Meta-analysis showed that:(1)warming acupuncture combined with joint mobilization improved total efficiency[OR=6.16,95%CI(3.79,10.00),Z=7.34;P<0.001),TSA results confirmed the results of the meta-analysis;(2)warming acupuncture combined with joint mobilization improved the cure rate[OR=2.84,95%CI(2.19,3.70),P<0.001],TSA results revealed that no further tests were needed to verify;(3)warming acupuncture combined with joint mobilization reduced the number of treatments required for healing[MD=-7.49,95%CI(-9.75,-5.23),P<0.001],TSA results confirmed the results of the meta-analysis;(4)in comparing visual analog scale scores before and after treatment,meta-analysis result showed that:SMD=-2.01,95%CI(-2.37,-1.65),P<0.001,the difference was statistically significant,TSA results confirmed the results of the meta-analysis.Conclusion:Warming acupuncture combined with joint mobilization had a significant effect on the treatment of scapulohumeral periarthritis.展开更多
The reliability of diagnostic systems in tokamak plasma is of great significance for physics researches or fusion reactor.When some diagnostics fail to detect information about the plasma status,such as electron tempe...The reliability of diagnostic systems in tokamak plasma is of great significance for physics researches or fusion reactor.When some diagnostics fail to detect information about the plasma status,such as electron temperature,they can also be obtained by another method:fitted by other diagnostic signals through machine learning.The paper herein is based on a machine learning method to predict electron temperature,in case the diagnostic systems fail to detect plasma temperature.The fully-connected neural network,utilizing back propagation with two hidden layers,is utilized to estimate plasma electron temperature approximately on the J-TEXT.The input parameters consist of soft x-ray emission intensity,electron density,plasma current,loop voltage,and toroidal magnetic field,while the targets are signals of electron temperature from electron cyclotron emission and x-ray imaging crystal spectrometer.Therefore,the temperature profile is reconstructed by other diagnostic signals,and the average errors are within 5%.In addition,generalized regression neural network can also achieve this function to estimate the temperature profile with similar accuracy.Predicting electron temperature by neural network reveals that machine learning can be used as backup means for plasma information so as to enhance the reliability of diagnostics.展开更多
Magnetohydrodynamic(MHD)instabilities are widely observed during tokamak plasma operation.Magnetic diagnostics provide important information which supports the understanding and control of MHD instabilities.This paper...Magnetohydrodynamic(MHD)instabilities are widely observed during tokamak plasma operation.Magnetic diagnostics provide important information which supports the understanding and control of MHD instabilities.This paper presents the current status of the magnetic diagnostics dedicated to measuring MHD instabilities at the J-TEXT tokamak;the diagnostics consist of five Mirnov probe arrays for measuring high-frequency magnetic perturbations and two saddle-loop arrays for low-frequency magnetic perturbations,such as the locked mode.In recent years,several changes have been made to these arrays.The structure of the probes in the poloidal Mirnov arrays has been optimized to improve their mechanical strength,and the number of in-vessel saddle loops has also been improved to support better spatial resolution.Due to the installation of high-field-side(HFS)divertor targets in early 2019,some of the probes were removed,but an HFS Mirnov array was designed and installed behind the targets.Owing to its excellent toroidal symmetry,the HFS Mirnov array has,for the first time at J-TEXT,provided valuable new information about the locked mode and the quasi-static mode(QSM)in the HFS.Besides,various groups of magnetic diagnostics at different poloidal locations have been systematically used to measure the QSM,which confirmed the poloidal mode number m and the helical structure of the QSM.By including the HFS information,the 2/1 resonant magnetic perturbation(RMP)-induced locked mode was measured to have a poloidal mode number m of~2.展开更多
The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents ...The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents are diagnosed by using Langmuir probe arrays.It was found that fluctuations in the edge and scrape-off layer(SOL) regions decrease with the application of a 6 kA RMP.The broadband turbulence at the radial location of ρ~0.9 which has a characteristic frequency of 40-150 kHz was strongly suppressed when applying RMP,as was the radial turbulent particle flux and blob transport in the near-SOL region.These experimental findings make RMP a promising method of suppressing and controlling turbulence and particle transport in a plasma boundary.展开更多
Objective:To investigate the effect of inhibiting miR-155 expression on the proliferation and migration of airway smooth muscle cells(ASMCs)in patients with chronic obstructive pulmonary disease(COPD).Methods:ASMCs we...Objective:To investigate the effect of inhibiting miR-155 expression on the proliferation and migration of airway smooth muscle cells(ASMCs)in patients with chronic obstructive pulmonary disease(COPD).Methods:ASMCs were isolated and cultured from 8 patients with COPD(observation group)and 3 patients with benign lung cancer without COPD(control group).The ASMCs were transfected with miR-155 suppression expression plasmid(to detect the expression of miR-155;flow cytometry was used to detect the cell cycler of cell clones;Transwell was used to detect cell migration and invasion;Enzyme-linked immunosorbent aanti-miR-155)and the negative contre;clone formation experiment was used to detect the numbol plasmid(anti-miR-NC),and blank control group was set.Real-time quantitative PCR(RT-qPCR)was usedssay(ELISA)method was used to detect tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)level.Results:The expression level of miR-155 in ASMCs of observation group was significantly higher than that in the control group(P<0.05).The miR-155 expression level in inhibited miR-155 expression group was significantly lower,compared with the negative control group and the blank group(P<0.05).In the inhibited miR-155 expression group,the proportion of G0-G1 phase cells was increased,the proportion of S phase cells was decreased,the number of cell clones,migration,and the number of invasive cells were decreased,and the levels of TNF-αand IL-6 were increased(P<0.05).Conclusions:Inhibiting the expression of miR-155 can inhibit the proliferation and migration of airway smooth muscle cells in COPD patients,and inhibit the release of proinflammatory factors.展开更多
Traffic flow prediction is an effective strategy to assess traffic conditions and alleviate traffic congestion. Influenced by external non-stationary factors and road network structure, traffic flow sequences have mac...Traffic flow prediction is an effective strategy to assess traffic conditions and alleviate traffic congestion. Influenced by external non-stationary factors and road network structure, traffic flow sequences have macro spatiotemporal characteristics and micro chaotic characteristics. The key to improving the model prediction accuracy is to fully extract the macro and micro characteristics of traffic flow time sequences. However, traditional prediction model by only considers time features of traffic data, ignoring spatial characteristics and nonlinear characteristics of the data itself, resulting in poor model prediction performance. In view of this, this research proposes an intelligent combination prediction model taking into account the macro and micro features of chaotic traffic data. Firstly, to address the problem of time-consuming and inefficient multivariate phase space reconstruction by iterating nodes one by one, an improved multivariate phase space reconstruction method is proposed by filtering global representative nodes to effectively realize the high-dimensional mapping of chaotic traffic flow. Secondly, to address the problem that the traditional combinatorial model is difficult to adequately learn the macro and micro characteristics of chaotic traffic data, a combination of convolutional neural network(CNN) and convolutional long short-term memory(ConvLSTM) is utilized for capturing nonlinear features of traffic flow more comprehensively. Finally,to overcome the challenge that the combined model performance degrades due to subjective empirical determined network parameters, an improved lightweight particle swarm is proposed for improving prediction accuracy by optimizing model hyperparameters. In this paper, two highway datasets collected by the Caltrans Performance Measurement System(PeMS)are taken as the research objects, and the experimental results from multiple perspectives show that the comprehensive performance of the method proposed in this research is superior to those of the prevalent methods.展开更多
提出预测面心立方高熵合金弹性性能的机器学习模型。数据集来源于第一性原理计算得到的186组样本。测试集体积模量(B)和剪切模量(G)预测值的拟合优度(R2)分别达到0.81和0.84。根据机器学习结果,Co Ni CuMoW在等主元高熵合金(G/B≤0.57)...提出预测面心立方高熵合金弹性性能的机器学习模型。数据集来源于第一性原理计算得到的186组样本。测试集体积模量(B)和剪切模量(G)预测值的拟合优度(R2)分别达到0.81和0.84。根据机器学习结果,Co Ni CuMoW在等主元高熵合金(G/B≤0.57)中具有最高的B、G和弹性模量(Y)和良好的塑性。第一性原理计算结果表明,当W含量增加时,(CoNiCuMo)1-xWx合金的弹性各向异性提高,且塑性下降。差分电荷密度分析结果表明,W—W和W—Mo键存在明显的电荷聚集,表明W原子与邻近原子间存在共价键作用。展开更多
The resonant magnetic perturbation(RMP)system is a powerful auxiliary system on tokamaks.On the J-TEXT tokamak,a set of new in-vessel coils is designed to enhance the amplitude of the RMP.The new coils are designed to...The resonant magnetic perturbation(RMP)system is a powerful auxiliary system on tokamaks.On the J-TEXT tokamak,a set of new in-vessel coils is designed to enhance the amplitude of the RMP.The new coils are designed to be two-turn saddle coils.These two-turn saddle coils have been optimized in terms of their structure,support,and protection components to overcome the limitations of the narrow in-vessel space,resulting in a compact coil module that can be accommodated in the vessel.To verify the feasibility of this design,an electromagnetic simulation is performed to investigate the electrical parameters and the generated field of the coils.A multi-field coupled simulation is performed to investigate the capacity of heat dissipation.As a result of these efforts,the new RMP coils have been successfully installed on the J-TEXT tokamak.It has significantly enhanced the RMP amplitude and been widely applied in experiments.展开更多
Various types of plasma events emerge in specific parameter ranges and exhibit similar characteristics in diagnostic signals,which can be applied to identify these events.A semisupervised machine learning algorithm,th...Various types of plasma events emerge in specific parameter ranges and exhibit similar characteristics in diagnostic signals,which can be applied to identify these events.A semisupervised machine learning algorithm,the k-means clustering algorithm,is utilized to investigate and identify plasma events in the J-TEXT plasma.This method can cluster diverse plasma events with homogeneous features,and then these events can be identified if given few manually labeled examples based on physical understanding.A survey of clustered events reveals that the k-means algorithm can make plasma events(rotating tearing mode,sawtooth oscillations,and locked mode)gathering in Euclidean space composed of multi-dimensional diagnostic data,like soft x-ray emission intensity,edge toroidal rotation velocity,the Mirnov signal amplitude and so on.Based on the cluster analysis results,an approximate analytical model is proposed to rapidly identify plasma events in the J-TEXT plasma.The cluster analysis method is conducive to data markers of massive diagnostic data.展开更多
A dedicated heat exchanger model is introduced for the optimization of heavy-duty diesel engines.The model is a prerequisite for the execution of CFD simulations,which are used to improve waste heat recovery in these ...A dedicated heat exchanger model is introduced for the optimization of heavy-duty diesel engines.The model is a prerequisite for the execution of CFD simulations,which are used to improve waste heat recovery in these systems.Several optimization methods coupled with different types of working fluids are compared in terms of exergy efficiency and heat exchanger complicity.The three considered optimization methods all lead to significant improvements in the R245fa and R1233zd systems with a comparatively low evaporation temperature.The optimal R245fa system has the highest efficiency increase(77.49%).The cyclopentane system displays the highest efficiency among the optimized ORC(Organic Rankine Cycle)systems,yet achieved by using a much heavier evaporator HEC(Heat Exchanging Core).In contrast,the 96.84%efficiency increase for the optimized R1233zd is achieved with only 68.96%evaporator weight.展开更多
The demand for electric vehicles has increased over the past few years.Wireless power transfer for electric vehicles provides more flexibility than traditional plug-in charging technology.Charging couplers are critica...The demand for electric vehicles has increased over the past few years.Wireless power transfer for electric vehicles provides more flexibility than traditional plug-in charging technology.Charging couplers are critical components in wireless power transfer systems.The thermal effect produced by the magnetic coupler in work will cause the temperature of the device to rise rapidly,affecting the work efficiency,transfer power,operation reliability,and service life.This paper modeled and analyzed each component's temperature distribution characteristics and thermal behavior.Firstly,the magnetic coupler's mutual inductance and magnetic circuit model are established,and the thermal model of the magnetic coupler analyzes the heat generation process.The thermal models of the coupler under three different magnetic core distributions are established,and the temperature rise of each component is obtained.The temperature rise of different parts of the coupler is verified by the temperature rise test structure of the experiment.展开更多
基金supported by the National Magnetic Confinement Fusion Program of China (No. 2017YFE0301805)National Natural Science Foundation of China (No. 51821005)+3 种基金the Fundamental Research Funds for the Central Universities at Huazhong University of Science and Technology (No. 2019kfy XJJS193)the U.S. Department of Energy (Nos. DE-FG02-86ER53218 and DE-SC0018001)the supports from the NIMROD teamthe support from the Chinese Government Scholarship.
文摘In this work,several key scaling laws of the quasi-static magnetic compression of field reversed configuration(FRC)plasma(Spencer et al 1983 Phys.Fluids 261564)are amended from a series of two-dimensional FRC MHD equilibriums numerically obtained using the Grad–Shafranov equation solver NIMEQ.Based on the new scaling for the elongation and the magnetic fields at the separatrix and the wall,the empirically stable limits for the compression ratio,the fusion gain,and the neutron yield are evaluated,which may serve as a more accurate estimate for the upper ceiling of performance from the magnetic compression of FRC plasma as a potential fusion energy as well as neutron source devices.
基金supported by the Hubei Provincial Natural Science Foundation of China(No.BZQ22006)National Natural Science Foundation of China(Nos.51977221 and 51821005)。
文摘The identification of magnetohydrodynamic(MHD)modes is a crucial issue in the control of magnetically confined plasmas.This paper proposes a novel method for identifying the evolution of MHD modes from a signal with a low signal-to-noise ratio.The proposed method generates a weighted directed graph from the time-frequency spectrum and calculates the evolution of the mode frequency by solving the shortest path.This method addresses the limitations posed by the lack of data channels and the disturbance of noise in the estimation of mode frequency and yields much better results compared to traditional methods.It is demonstrated that,using this method,the evolution of an unlocked tearing mode was more accurately calculated on the J-TEXT tokamak.This method remains feasible even with a low signal-to-noise ratio of 0.5,as shown by its uncertainty.Furthermore,with appropriate parameters,this method can be applied to not only signals with MHD modes,but also to general signals with continuous modes.
基金The authors would like to acknowledge the support from the UKRI Interdisciplinary Centre for Circular Chemical Economy(EP/V011863/1)EPSRC LifesCO2R project(EP/N009746/1 EP/N009746/2)and EPSRC NECEM Energy Material Centre(EP/R021503/1)Loughborough Materials Characterisation Centre Pump Prime grant which enabled the access to the characterisation facilities is also acknowledged.
文摘Earth-abundant copper-tin(CuSn)electrocatalysts are potential candidates for cost-effective and sustainable production of CO from electrochemical carbon dioxide reduction(eCO_(2)R).However,the requirement of highoverpotential for obtaining reasonable current,low Faradaic efficiencies(FE)and low intrinsic catalytic activities require the optimisation of the CuSn nanoarchitecture for the further advancement in the field.In the current work,we have optimised Sn loading on Cu gas diffusion electrodes(GDEs)by electrochemical spontaneous precipitation.Samples with various Sn loadings were tested in a three-chamber GDE reactor to evaluate their CO_(2)reduction performances.The best performance of 92%CO Faradaic efficiency at a cathodic current density of 120 mA cm^(-2)was obtained from the 20 min Sn deposited Cu_(2)O sample operated at-1.13 V vs.RHE.The electrocatalyst had~13%surface coverage of Sn on Cu GDE surface,and had Sn in oxide form and copper in metallic form.The catalyst also showed stable performance and was operable for>3 h under chronoamperometric conditions.The surface of the GDE reduces from Cu2O to Cu during eCO_(2)R and goes further reconstruction during the eCO_(2)R.This study demonstrates the potential of Cu-Sn for selective CO production at high current densities.
基金supported by the National Key Research and Development Program of China,Nos.2017YFE0122900(to BH),2019YFA0110800(to WL),2019YFA0903802(to YW),2021YFA1101604(to LW),2018YFA0108502(to LF),and 2020YFA0804003(to JW)the National Natural Science Foundation of China,Nos.31621004(to WL,BH)and 31970821(to YW)+1 种基金CAS Project for Young Scientists in Basic Research,No.YSBR-041(to YW)Joint Funds of the National Natural Science Foundation of China,No.U21A20396(to BH)。
文摘Numerous studies have shown that cell replacement therapy can replenish lost cells and rebuild neural circuitry in animal models of Parkinson’s disease.Transplantation of midbrain dopaminergic progenitor cells is a promising treatment for Parkinson’s disease.However,transplanted cells can be injured by mechanical damage during handling and by changes in the transplantation niche.Here,we developed a one-step biomanufacturing platform that uses small-aperture gelatin microcarriers to produce beads carrying midbrain dopaminergic progenitor cells.These beads allow midbrain dopaminergic progenitor cell differentiation and cryopreservation without digestion,effectively maintaining axonal integrity in vitro.Importantly,midbrain dopaminergic progenitor cell bead grafts showed increased survival and only mild immunoreactivity in vivo compared with suspended midbrain dopaminergic progenitor cell grafts.Overall,our findings show that these midbrain dopaminergic progenitor cell beads enhance the effectiveness of neuronal cell transplantation.
基金This work was jointly supported by the National Natural Science Foundation of China(Grant Nos.41975137,42175012,and 41475097)the National Key Research and Development Program(Grant No.2018YFF0300103).
文摘Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems.
基金This work was sponsored by the National Key R&D Program of China[Grant Number 2020YFB0106603]the Key R&D Program of Shandong Province[Grant Number 2020CXGC010404]the Undergraduate School of Shandong University,China[Grant Number 2022Y155].
文摘A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel depth.The impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output capability.The results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel cell.An increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.
基金supported by the Ministry of Science and Technology of the People’s Republic of China[grant numbers 2017YFC0211304]the Natural Science Foundation of Shandong Province[grant number ZR2019MEE041]the Open Fund of the National Engineering Laboratory for Mobile Source Emission Control Technology[grant number NELMS2017A14].
文摘In order to effectively implement DPF(Diesel Particulate Filters)regeneration control,thermal management of exhaust products before and inside Diesel Oxidation Catalyst(DOC)is necessary.In the present study,the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests.The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC;in particular,with intake throttle valve opening at 20%,temperature before DOC can be increased by about 170℃ with respect to the full opening.An increase in the late post injection quantity can produce a significant rise of the temperature inside DOC,however its impact on the exhaust temperature before DOC is relatively limited.As the late post injection quantity increases,Hydrocarbon(HC)emissions also grow;in the present work it is shown that with a proper injection quantity,a considerable temperature increase inside the DOC can be obtained with relatively low HC emission.More specifically,with the intake throttle valve at 30%and DOC reaching ignition temperature as the late post injection quantity is increased,the exhaust temperature after DOC can be made larger than 550℃,adequate for DPF active regeneration.
文摘Although occupational therapy for substance abuse,as a field in psychiatric rehabilitation,has been implemented for over half a century,it still seems underdeveloped.This area of rehabilitation aims to enhance the quality of life of substance abuse rehabilitants and prevent them from relapse.1 It can be achieved by enabling them to identify their meaningful occupations and occupational roles,and supporting them to re-engage in the occupations that they value,which would help empower them to overcome abuse.12 The interventions around the world include brief intervention,motivational strategy,cognitive behavioural therapy.
基金the National Natural Science Foundation of China(Grant No.51576116)the National Natural Science Foundation of Shandong Province(Grant No.ZR2019MEE041)。
文摘Experiments on subcooled flow boiling have been conducted using water in a rectangular flow channel.Similar to the coolant channel in internal combustion engines(IC engines),the flow channel in this experiment was asymmetrically heated.Bubble images were captured using a high speed camera from the side view of the channel.The experimental conditions in terms of bulk temperature,bulk velocity,pressure and heat flux ranged from 65°C–75°C,0.25 m/s–0.75 m/s,1–1.7 bar and 490 kW/m2–700 kW/m2,respectively.On the basis of these tests,a statistical analysis of the bubble size has been conducted considering a population of 1400 samples.It has been found that the mean Sauter bubble diameter increases with the decrease of subcooling,bulk velocity,pressure and increased heat flux.A modified correlation has been finally proposed to predict the mean Sauter bubble diameter under subcooled flow boiling conditions upstream of the onset of significant void,which shows good accuracy with the experimental results.
文摘Objective:To evaluate the clinical efficacy of warming acupuncture combined with joint mobilization for the treatment of scapulohumeral periarthritis.Methods:A search for published randomized controlled trials(RCT)investigating warming acupuncture combined with joint mobilization for the treatment of scapulohumeral periarthritis was performed using the Cochrane Library,PubMed,Embase,and Web of Science databases.According to requirements of the Cochrane systematic review,all evaluations of RCT investigating warming acupuncture with joint mobilization in the treatment of scapulohumeral periarthritis were performed via method quality assessment,data extraction,and data analysis.Revman 5.3 and Stata 12.0 statistical software were used for the meta-analysis,and the trial sequential analysis(TSA)software estimated the required information size for each outcome.Results:A total of 14 articles were retrieved for meta-analysis,which included 551 cases in the treatment group and 539 cases in the control group.Meta-analysis showed that:(1)warming acupuncture combined with joint mobilization improved total efficiency[OR=6.16,95%CI(3.79,10.00),Z=7.34;P<0.001),TSA results confirmed the results of the meta-analysis;(2)warming acupuncture combined with joint mobilization improved the cure rate[OR=2.84,95%CI(2.19,3.70),P<0.001],TSA results revealed that no further tests were needed to verify;(3)warming acupuncture combined with joint mobilization reduced the number of treatments required for healing[MD=-7.49,95%CI(-9.75,-5.23),P<0.001],TSA results confirmed the results of the meta-analysis;(4)in comparing visual analog scale scores before and after treatment,meta-analysis result showed that:SMD=-2.01,95%CI(-2.37,-1.65),P<0.001,the difference was statistically significant,TSA results confirmed the results of the meta-analysis.Conclusion:Warming acupuncture combined with joint mobilization had a significant effect on the treatment of scapulohumeral periarthritis.
基金supported by the National Magnetic Confinement Fusion Science Program(Nos.2018YFE0301104,2018YFE0301100)State Key Laboratory of Advanced Electromagnetic Engineering and Technology(No.AEET2020KF001)National Natural Science Foundation of China(Nos.12075096,51821005)。
文摘The reliability of diagnostic systems in tokamak plasma is of great significance for physics researches or fusion reactor.When some diagnostics fail to detect information about the plasma status,such as electron temperature,they can also be obtained by another method:fitted by other diagnostic signals through machine learning.The paper herein is based on a machine learning method to predict electron temperature,in case the diagnostic systems fail to detect plasma temperature.The fully-connected neural network,utilizing back propagation with two hidden layers,is utilized to estimate plasma electron temperature approximately on the J-TEXT.The input parameters consist of soft x-ray emission intensity,electron density,plasma current,loop voltage,and toroidal magnetic field,while the targets are signals of electron temperature from electron cyclotron emission and x-ray imaging crystal spectrometer.Therefore,the temperature profile is reconstructed by other diagnostic signals,and the average errors are within 5%.In addition,generalized regression neural network can also achieve this function to estimate the temperature profile with similar accuracy.Predicting electron temperature by neural network reveals that machine learning can be used as backup means for plasma information so as to enhance the reliability of diagnostics.
基金supported by the National MCF Energy R&D Program of China(No.2018YFE0309100)National Natural Science Foundation of China(NSFC)(No.11905078)‘the Fundamental Research Funds for the Central Universities’(No.2020kfy XJJS003)。
文摘Magnetohydrodynamic(MHD)instabilities are widely observed during tokamak plasma operation.Magnetic diagnostics provide important information which supports the understanding and control of MHD instabilities.This paper presents the current status of the magnetic diagnostics dedicated to measuring MHD instabilities at the J-TEXT tokamak;the diagnostics consist of five Mirnov probe arrays for measuring high-frequency magnetic perturbations and two saddle-loop arrays for low-frequency magnetic perturbations,such as the locked mode.In recent years,several changes have been made to these arrays.The structure of the probes in the poloidal Mirnov arrays has been optimized to improve their mechanical strength,and the number of in-vessel saddle loops has also been improved to support better spatial resolution.Due to the installation of high-field-side(HFS)divertor targets in early 2019,some of the probes were removed,but an HFS Mirnov array was designed and installed behind the targets.Owing to its excellent toroidal symmetry,the HFS Mirnov array has,for the first time at J-TEXT,provided valuable new information about the locked mode and the quasi-static mode(QSM)in the HFS.Besides,various groups of magnetic diagnostics at different poloidal locations have been systematically used to measure the QSM,which confirmed the poloidal mode number m and the helical structure of the QSM.By including the HFS information,the 2/1 resonant magnetic perturbation(RMP)-induced locked mode was measured to have a poloidal mode number m of~2.
基金supported by the National Key Research & Development Programme of China (No. 2018YFE0309100, 2017YFE0301201)National Natural Science Foundation of China (Nos. 11875124, U1867222, 11575055, 11705052 & 11705151)the National Magnetic Confinement Fusion Science Programme of China (Nos. 2015GB120002, 2015GB11101 & 2015GB104000)
文摘The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents are diagnosed by using Langmuir probe arrays.It was found that fluctuations in the edge and scrape-off layer(SOL) regions decrease with the application of a 6 kA RMP.The broadband turbulence at the radial location of ρ~0.9 which has a characteristic frequency of 40-150 kHz was strongly suppressed when applying RMP,as was the radial turbulent particle flux and blob transport in the near-SOL region.These experimental findings make RMP a promising method of suppressing and controlling turbulence and particle transport in a plasma boundary.
基金Hunan provincial traditional Chinese medicine scientific research project(No.201838)。
文摘Objective:To investigate the effect of inhibiting miR-155 expression on the proliferation and migration of airway smooth muscle cells(ASMCs)in patients with chronic obstructive pulmonary disease(COPD).Methods:ASMCs were isolated and cultured from 8 patients with COPD(observation group)and 3 patients with benign lung cancer without COPD(control group).The ASMCs were transfected with miR-155 suppression expression plasmid(to detect the expression of miR-155;flow cytometry was used to detect the cell cycler of cell clones;Transwell was used to detect cell migration and invasion;Enzyme-linked immunosorbent aanti-miR-155)and the negative contre;clone formation experiment was used to detect the numbol plasmid(anti-miR-NC),and blank control group was set.Real-time quantitative PCR(RT-qPCR)was usedssay(ELISA)method was used to detect tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)level.Results:The expression level of miR-155 in ASMCs of observation group was significantly higher than that in the control group(P<0.05).The miR-155 expression level in inhibited miR-155 expression group was significantly lower,compared with the negative control group and the blank group(P<0.05).In the inhibited miR-155 expression group,the proportion of G0-G1 phase cells was increased,the proportion of S phase cells was decreased,the number of cell clones,migration,and the number of invasive cells were decreased,and the levels of TNF-αand IL-6 were increased(P<0.05).Conclusions:Inhibiting the expression of miR-155 can inhibit the proliferation and migration of airway smooth muscle cells in COPD patients,and inhibit the release of proinflammatory factors.
基金Project supported by the National Natural Science Foundation of China (Grant No. 62063014)the Natural Science Foundation of Gansu Province, China (Grant No. 22JR5RA365)。
文摘Traffic flow prediction is an effective strategy to assess traffic conditions and alleviate traffic congestion. Influenced by external non-stationary factors and road network structure, traffic flow sequences have macro spatiotemporal characteristics and micro chaotic characteristics. The key to improving the model prediction accuracy is to fully extract the macro and micro characteristics of traffic flow time sequences. However, traditional prediction model by only considers time features of traffic data, ignoring spatial characteristics and nonlinear characteristics of the data itself, resulting in poor model prediction performance. In view of this, this research proposes an intelligent combination prediction model taking into account the macro and micro features of chaotic traffic data. Firstly, to address the problem of time-consuming and inefficient multivariate phase space reconstruction by iterating nodes one by one, an improved multivariate phase space reconstruction method is proposed by filtering global representative nodes to effectively realize the high-dimensional mapping of chaotic traffic flow. Secondly, to address the problem that the traditional combinatorial model is difficult to adequately learn the macro and micro characteristics of chaotic traffic data, a combination of convolutional neural network(CNN) and convolutional long short-term memory(ConvLSTM) is utilized for capturing nonlinear features of traffic flow more comprehensively. Finally,to overcome the challenge that the combined model performance degrades due to subjective empirical determined network parameters, an improved lightweight particle swarm is proposed for improving prediction accuracy by optimizing model hyperparameters. In this paper, two highway datasets collected by the Caltrans Performance Measurement System(PeMS)are taken as the research objects, and the experimental results from multiple perspectives show that the comprehensive performance of the method proposed in this research is superior to those of the prevalent methods.
基金the financial support from the National Natural Science Foundation of China(Nos.62173280,51975491)。
文摘提出预测面心立方高熵合金弹性性能的机器学习模型。数据集来源于第一性原理计算得到的186组样本。测试集体积模量(B)和剪切模量(G)预测值的拟合优度(R2)分别达到0.81和0.84。根据机器学习结果,Co Ni CuMoW在等主元高熵合金(G/B≤0.57)中具有最高的B、G和弹性模量(Y)和良好的塑性。第一性原理计算结果表明,当W含量增加时,(CoNiCuMo)1-xWx合金的弹性各向异性提高,且塑性下降。差分电荷密度分析结果表明,W—W和W—Mo键存在明显的电荷聚集,表明W原子与邻近原子间存在共价键作用。
基金supported by Hubei Provincial Natural Science Foundation of China(No.BZQ22006)Fundamental Research Funds for the Central Universities(No.CZY20028)+1 种基金National Magnetic Confinement Fusion Energy R&D Program of China(No.2018YFE0309102)National Natural Science Foundation of China(No.51821005)。
文摘The resonant magnetic perturbation(RMP)system is a powerful auxiliary system on tokamaks.On the J-TEXT tokamak,a set of new in-vessel coils is designed to enhance the amplitude of the RMP.The new coils are designed to be two-turn saddle coils.These two-turn saddle coils have been optimized in terms of their structure,support,and protection components to overcome the limitations of the narrow in-vessel space,resulting in a compact coil module that can be accommodated in the vessel.To verify the feasibility of this design,an electromagnetic simulation is performed to investigate the electrical parameters and the generated field of the coils.A multi-field coupled simulation is performed to investigate the capacity of heat dissipation.As a result of these efforts,the new RMP coils have been successfully installed on the J-TEXT tokamak.It has significantly enhanced the RMP amplitude and been widely applied in experiments.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2018YFE0301104 and 2018YFE0301100)National Natural Science Foundation of China(Nos.12075096 and 51821005)。
文摘Various types of plasma events emerge in specific parameter ranges and exhibit similar characteristics in diagnostic signals,which can be applied to identify these events.A semisupervised machine learning algorithm,the k-means clustering algorithm,is utilized to investigate and identify plasma events in the J-TEXT plasma.This method can cluster diverse plasma events with homogeneous features,and then these events can be identified if given few manually labeled examples based on physical understanding.A survey of clustered events reveals that the k-means algorithm can make plasma events(rotating tearing mode,sawtooth oscillations,and locked mode)gathering in Euclidean space composed of multi-dimensional diagnostic data,like soft x-ray emission intensity,edge toroidal rotation velocity,the Mirnov signal amplitude and so on.Based on the cluster analysis results,an approximate analytical model is proposed to rapidly identify plasma events in the J-TEXT plasma.The cluster analysis method is conducive to data markers of massive diagnostic data.
基金funded by National Engineering Laboratory for Mobile Source Emission Control Technology of China[Grant No.NELMS2019A01]the Undergraduate School of Shandong University,China[Grant No.2022Y155].
文摘A dedicated heat exchanger model is introduced for the optimization of heavy-duty diesel engines.The model is a prerequisite for the execution of CFD simulations,which are used to improve waste heat recovery in these systems.Several optimization methods coupled with different types of working fluids are compared in terms of exergy efficiency and heat exchanger complicity.The three considered optimization methods all lead to significant improvements in the R245fa and R1233zd systems with a comparatively low evaporation temperature.The optimal R245fa system has the highest efficiency increase(77.49%).The cyclopentane system displays the highest efficiency among the optimized ORC(Organic Rankine Cycle)systems,yet achieved by using a much heavier evaporator HEC(Heat Exchanging Core).In contrast,the 96.84%efficiency increase for the optimized R1233zd is achieved with only 68.96%evaporator weight.
文摘The demand for electric vehicles has increased over the past few years.Wireless power transfer for electric vehicles provides more flexibility than traditional plug-in charging technology.Charging couplers are critical components in wireless power transfer systems.The thermal effect produced by the magnetic coupler in work will cause the temperature of the device to rise rapidly,affecting the work efficiency,transfer power,operation reliability,and service life.This paper modeled and analyzed each component's temperature distribution characteristics and thermal behavior.Firstly,the magnetic coupler's mutual inductance and magnetic circuit model are established,and the thermal model of the magnetic coupler analyzes the heat generation process.The thermal models of the coupler under three different magnetic core distributions are established,and the temperature rise of each component is obtained.The temperature rise of different parts of the coupler is verified by the temperature rise test structure of the experiment.
