The large-scale production of high-Ti steels is limited by the formation of Ti-containing oxides or nitrides in steel-slag reactions during continuous casting.These processes degrade mold flux properties,clog submerge...The large-scale production of high-Ti steels is limited by the formation of Ti-containing oxides or nitrides in steel-slag reactions during continuous casting.These processes degrade mold flux properties,clog submerged entry nozzles,form floaters in the molds,and produce various surface defects on the cast slabs.This review summarizes the effects of nonmetallic inclusions on traditional CaO-SiO_(2)-based(CS)mold fluxes and novel CaO-Al_(2)O_(3)-based(CA)low-or non-reactive fluxes containing TiO_(2),BaO,and B_(2)O_(3)additives to avoid undesirable steel,slag,and inclusion reactions,with the aim of providing a new perspective for research and practice related to balancing the lubrication and heat transfer of mold fluxes to promote smooth operation and reduce surface defects on cast slabs.For traditional CS mold flux,although the addition of solvents such as Na_(2)O,Li_(2)O,and B_(2)O_(3)can enhance flowability,steel-slag reactions persist,limiting the effectiveness of CS mold fluxes in high-Ti steel casting.Low-or non-reactive CA mold fluxes with reduced SiO_(2)content are a research focus,where adding other components can significantly change flux characteristics.Replacing CaO with BaO can lower the melting point and inhibit crystallization,allowing the flux to maintain good flowability at low temperatures.Replacing SiO_(2)with TiO_(2)can stabilize the viscosity and enhance heat transfer.To reduce the environmental impact,fluorides are replaced with components such as TiO_(2),B_(2)O_(3),BaO,Li_(2)O,and Na_(2)O for F-frce mold fluxes with similar lubrication,crystallization,and heat-transfer effects.When TiO_(2)replaces CaF_(2),it stabilizes the viscosity and enhances the heat conductivity,forming CaTiO_(3)and CaSiTiO_(5)phases instead of cuspidine to control crystallization.B_(2)O_(3)lowers the melting point and suppresses crystallization,forming phases such as Ca_(3)B_(2)O_(6)and Ca_(11)Si_(4)B_(2)O_(22).BaO introduces non-bridging oxygen to reduce viscosity and ensure flux flowability at low temperatures.However,further studies are required to determine the optimal mold flux compositions corresponding to the steel grades and the interactions between the various components of the mold flux.In the future,the practical application of new mold fluxes for high-Ti steel will become the focus of further verification to achieve a balance between lubrication and heat transfer,which is expected to minimize the occurrence of casting problems and slab defects.展开更多
Enhanced riverine nitrogen(N)and phosphorus(P)exports from anthropogenic activities have substantially increased primary productivity in downstream waters and induced harmful ecosystem effects.The components of riveri...Enhanced riverine nitrogen(N)and phosphorus(P)exports from anthropogenic activities have substantially increased primary productivity in downstream waters and induced harmful ecosystem effects.The components of riverine nutrient fluxes determine environmental responses that remain largely unknown.We identified different components of riverine N and P exports based on a load-hydrograph analysis of multiple sections of the Yangtze River in China based on long-term daily nutrient fluxes.Our results indicate that the increasing trend of riverine N and P fluxes from upstream to downstream can be reversed by the retention effect of dams and lakes,which is more significant for total phosphorus and its high-flux component than total nitrogen.The greatest nutrient retention along the river was mainly attributed to the Three Gorges Dam,which has a significant retention effect on both N and P fluxes,particularly on the high flux and TP.While high nutrient fluxes dominate upstream,middle and low fluxes dominate downstream.Significant but uncommon trends were observed for all nutrient flux components along the river.While both,medium and low flux percentages increase significantly,those of high flux decrease.The net change of N and P fluxes along the Yangtze River do not coincide in space,indicating heterogeneity between the river’s source and sink of N and P.Knowledge of the inconsistent alteration of riverine nutrient flux and its components should facilitate efforts to make better measures to mitigate nutrient-related problems in the Yangtze River.展开更多
Frequent droughts pose considerable threat to global forest carbon uptake,but little is known about the response of forest carbon fluxes in climatic transition zones to seasonal drought.In this study,the responses of ...Frequent droughts pose considerable threat to global forest carbon uptake,but little is known about the response of forest carbon fluxes in climatic transition zones to seasonal drought.In this study,the responses of carbon fluxes to seasonal drought in two natural forests(Quercus aliena var.acute serrata Maxim and Pinus tabuliformis Carr.)in the Baotianman Nature Reserve were investigated.The Q.aliena forest exhibited a high resilience with stable gross primary productivity(GPP).However,ecosystem respiration(Re)significantly declined by 18.4%compared with normal years,leading to an increase in net carbon sequestration capacity of 4.1%.This resilience was attributed to its deep root system accessing soil water(SWC_(50cm))to sustain stomatal openness,coupled with the efficient utilization of photosynthetically active radiation to drive photosynthesis.In contrast,the P.tabuliformis forest,which relied on shallow soil moisture(SWC_(20cm)),experienced simultaneous decreases in both GPP and Re during drought,with a sharply greater decrease in GPP,resulting in low net carbon sink capacity.Further analysis revealed that the Q.aliena forest prioritized carbon assimilation through a deep water-stomatal synergy strategy(anisohydric behavior),whereas the P.tabuliformis forest adopted an isohydric strategy favoring water conservation at the expense of carbon fixation efficiency.These findings highlight distinct mechanisms underlying drought adaptation between forest types,providing critical insight into optimizing forest carbon cycle models and selecting drought-resistant species under the influence of climate change.展开更多
Synchronous reluctance motors(SynRM)are widely employed in industrial applications due to their high robustness,low cost,and absence of permanent magnets.In recent years,significant research efforts have focused on im...Synchronous reluctance motors(SynRM)are widely employed in industrial applications due to their high robustness,low cost,and absence of permanent magnets.In recent years,significant research efforts have focused on improving the controllability and efficiency of SynRM.Accurate rotor position information is essential for the controller to generate appropriate current and voltage references corresponding to the desired speed and load torque.Shaft-mounted position sensors are generally undesirable because of their high cost,sensitivity to harsh operating conditions,maintenance requirements,and reduced reliability in environments characterized by high vibration.Consequently,sensorless control techniques that estimate rotor position using measured stator currents and voltages have attracted increasing attention.However,magnetic saturation,parameter nonlinearities,and cross-coupling effects significantly degrade position estimation accuracy and may compromise the stability of sensorless SynRM drives.In this paper,a nonlinear SynRM model is developed using finite element analysis(FEA)to accurately capture magnetic saturation and cross-coupling effects,thereby providing a precise representation of the machine’s electromagnetic behavior under varying load and flux conditions.A series of magnetostatic FEA simulations is performed.To reduce computational complexity,only one motor pole is analyzed by applying anti-periodic boundary conditions along the domain sides and enforcing a zero magnetic vector potential on the external stator boundary.Nonlinear iron material properties are modeled using the appropriate B-H curve.The simulations are carried out by imposing d-and q-axis current components and computing the corresponding flux linkages and electromagnetic torque.Based on these results,both apparent and incremental inductances are extracted and incorporated into the control algorithm.An advanced fictitious flux linkage method combined with a phase-locked loop(PLL)is employed for accurate rotor position estimation.Simulation results confirm that the proposed sensorless control strategy ensures stable operation and high position estimation accuracy over the entire speed range.展开更多
An atmospheric general circulation model(AGCM)is used to analyze the different impact on the Barents Sea(BS)and Greenland Sea(GS)for a perturbation of sea-to-air DMS flux.We compare contemporary anthropogenic S and co...An atmospheric general circulation model(AGCM)is used to analyze the different impact on the Barents Sea(BS)and Greenland Sea(GS)for a perturbation of sea-to-air DMS flux.We compare contemporary anthropogenic S and contemporary DMS sea-to-air flux(as baseline,B00)sulfur emissions,with contemporary anthropogenic S and a perturbed DMS flux(as modified,B01)sulfur emissions.Results show that the global mean surface DMS and DMS vertically integrated concentration all peaked in June and increases more than 63%in BS and increases about 58%in GS.The concentrations of atmospheric sulfur dioxide vertical integral(SO_(2))and sulfate vertical integral(SO_(4))only increase less than 12%in both regions.Sulfur emission(SEM)peaked in June and increased about 67%and 41%in GS and BS,respectively.Aerosol optical depth(AOD)increases less than 4%in GS and in BS.Surface temperature(TSC)peaked in July and reduces 0.25 K and 0.8 K in GS and BS,respectively.Satellite data from 2003 to 2023show that chlorophyll(CHL)concentration in BS exceeds that of GS by 51%.The AOD in GS is only 0.6%higher than in BS.The recent increased rate of DMS surface concentration in BS(from 6%during 1981–2002 to 18.8%in 2003–2023)is mainly caused by elevated CHL concentrations in BS.Finally,the perturbation on DMS flux leads to increase rate of DMS and related sulfur emissions especially in the BS,this tendency will have an offsetting effect on regional warming.展开更多
This paper proposes a collaborative design method for enhancing the power factor and torque of electric motors.First,the intrinsic relationship between flux linkage analysis of the permanent magnet(PM)and armature fie...This paper proposes a collaborative design method for enhancing the power factor and torque of electric motors.First,the intrinsic relationship between flux linkage analysis of the permanent magnet(PM)and armature field and the power factor is explored.Then,the connection between flux linkage and harmonics is established,clarifying the mechanism for improving power factor and torque.Improvements are focused on the PM and permeance.Regarding the PM structure,employing a Y-shaped PM structure effectively increases PM utilization,reduces leakage flux at the outer ends,and enhances the PM flux linkage.Concerning permeance,stator tooth design is optimized to cooperatively improve permeance harmonics,reduce the non-working flux linkage of the armature field,and enhance the fundamental modulation wave of the armature field responsible for torque generation.This improves the power factor while maintaining motor torque.Finally,through PM structural design,the motor torque performance is optimized.Furthermore,the performance of the Y-shaped PM motor is evaluated.A prototype was manufactured and tested.Theoretical analysis and experimental results demonstrate the effectiveness of the proposed method to a significant extent.展开更多
The carbon cycle stands as a cornerstone among the Earth's material cycles,carrying profound implications for global climate dynamics and humanity's sustenance and advancement.Additionally,nitrogen,as a vital ...The carbon cycle stands as a cornerstone among the Earth's material cycles,carrying profound implications for global climate dynamics and humanity's sustenance and advancement.Additionally,nitrogen,as a vital nutrient element,plays a pivotal role in biogeochemical processes,exerting significant influence on the ecological environment within watersheds.In this study,an analysis of the carbon(C)and nitrogen(N)components in the river water of 12 alpine basins on the eastern margin of the Tibetan Plateau(TP)reveals that the average dissolved organic carbon(DOC)concentration in the river water is 0.76±0.67 mg/L,indicating a lower level compared to the global river average organic carbon content.Specifically,the average DOC concentrations were 0.42±0.22 and 1.56±0.68 mg/L in the glacial and non-glacial basins,respectively.The average dissolved inorganic carbon(DIC)concentration in the eastern TP is 27.04±20.19 mg/L,with the lowest DIC observed at Dagu Glacier and the highest at Daxia River.Furthermore,the average dissolved total carbon(DTC)concentration in glacier river water was 18.87±12.65 mg/L,contrasting with 48.23±21.07 mg/L in non-glacial basins.The mean concentration of total nitrogen(TN)in the eastern TP averaged 0.97±0.54 mg/L,with the glacial basin registering 1.01±0.47 mg/L and the non-glacial basin at 0.89±0.70 mg/L.Evaluating the release fluxes of carbon and nitrogen across 12 river basins revealed a range of DTC emission fluxes from 0.32×10^(9)to 31.02×10^(9)g·C/a,with inorganic carbon comprising 71.0%to 99.5%.Consequently,the carbon emission flux for seven glacier basins totaled 15.91×10^(9)g·C/a,while for the five non-glacial river basins,it reached 87.37×10^(9)g·C/a.The total TN release fluxes across 12 small river basins amounted to 2.46×10^(9)g·N/a,with 0.84×10^(9)g·N/a released in glacial basins and 1.62×10^(9)g·N/a in the nonglacial basin.This study elucidates the spatial distribution and transport mechanisms of carbon and nitrogen elements within the glacial and downstream non-glacial basins,offering valuable insights into the biogeochemical cycles of carbon and nitrogen in the eastern Tibetan Plateau.展开更多
Correction to:Journal of Forestry Research(2025)36:124 https://doi.org/10.1007/s11676-025-01918-8 In this article the author’s name Yasutomo Hoshika was incorrectly written as Yasutoma Hoshika.The original article ha...Correction to:Journal of Forestry Research(2025)36:124 https://doi.org/10.1007/s11676-025-01918-8 In this article the author’s name Yasutomo Hoshika was incorrectly written as Yasutoma Hoshika.The original article has been corrected.展开更多
Lacustrine groundwater discharge(LGD)plays an important role in water resources management.Previous studies have focused on LGD process in a single lake,but the differences in LGD process within the same region have n...Lacustrine groundwater discharge(LGD)plays an important role in water resources management.Previous studies have focused on LGD process in a single lake,but the differences in LGD process within the same region have not been thoroughly investigated.In this study,multiple tracers(hydrochemistry,𝛿D,𝛿18O and 222Rn)were used to compare mechanisms of LGD in Daihai and Ulansuhai Lake in Inner Mongoli1,Northwest China.The hydrochemical types showed a trend from groundwater to lake water,indicating a hydraulic connection between them.In addition,the𝛿D and𝛿18O values of sediment pore water were between the groundwater and lake water,indicating the LGD processes.The radon mass balance model was used to estimate the average groundwater discharge rates of Daihai and Ulansuhai Lake,which were 2.79 mm/day and 3.02 mm/day,respectively.The total nitrogen(TN),total phosphorus(TP),and fluoride inputs associated with LGD in Daihai Lake accounted for 97.52%,96.59%,and 95.84%of the total inputs,respectively.In contrast,TN,TP and fluoride inputs in Ulansuhai Lake were 53.56%,40.98%,and 36.25%,respectively.This indicates that the pollutant inputs associated with LGD posed a potential threat to the ecological stability of Daihai and Ulansuhai Lake.By comparison,the differences of LGD process and associated pollutant flux were controlled by hydrogeological conditions,lakebed permeability and human activities.This study provides a reference for water resources management in Daihai and Ulansuhai Lake basins while improving the understanding of LGD in the Yellow River basin.展开更多
Plant aggregate-based building materials are a viable solution for reducing greenhouse gas emissions and providing good thermal and acoustic performances.In this study,the investigated lightweight mortars require a hy...Plant aggregate-based building materials are a viable solution for reducing greenhouse gas emissions and providing good thermal and acoustic performances.In this study,the investigated lightweight mortars require a hydraulic reaction.Laboratory and on-site empirical observations about plant aggregate-based materials indicate a delay in setting time and a decrease in the mechanical performances of concretes based on plant aggregates.The natural origin of plant-aggregates causes a lot of variability in their properties.Related studies have shown that the incompatibility between plant aggregates and cement is mainly caused by the dissolved and decomposed components of plant aggregates in alkaline environments.Currently,no research on the specific impact of each component on the setting time of lime-based binder exists.In this work,the impact of some soluble compounds(e.g.,sucrose,glucose,fructose,pectin)on the setting reaction of the lime matrix was studied using Vicat test,thermogravimetric analysis(TGA)and FT-IR spectroscopy.Experimental results showed that carbohydrates such as glucose and sucrose not only affect the setting time but also have a long-term impact on the carbonation of lime.The measure of the setting time by Vicat test appears as a possible indicator to predict the compatibility between the matrix and plant aggregates.展开更多
The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of ...The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of variability in the timing of seasonal sea ice retreat on the flux and composition of sinking particulate matter remains to be elucidated.In this study,we deployed sediment traps in Prydz Bay during the austral summers of 2019/2020 and 2020/2021,noting that sea ice melting occurred approximately one and a half months earlier in the former summer compared to the latter.We analyzed sediment trap data,which included total mass flux(TMF),particulate organic carbon(POC),biogenic silica(BSi),particulate inorganic carbon,and lithogenic particle(Litho)fluxes,as well as the stable isotopesδ^(13)C andδ^(15)N of particulate organic matter(POM).Additionally,we incorporated remote sensing data on sea ice concentration and chlorophyll a.This dramatic delay in sea ice melting timing could result in a significant increase in TMF,BSi and POC fluxes in the summer of 2020/2021 compared to 2019/2020.Elevated BSi fluxes and more ^(13)C-depleted POC in the austral summer of 2020/2021 suggest that the delayed melting of sea ice may have stimulated the productivity of centric diatoms.Furthermore,the higher BSi/POC ratio and more negativeδ^(15)N values of POM,along with a reduced presence of krill in the traps,indicate a diminished grazing pressure from zooplankton,which collectively enhanced the sedimentation efficiency of POC during the austral summer of 2020/2021.These findings highlight the critical role of sea ice melting timing in regulating productivity,flux and composition of sinking particulate matter in the Prydz Bay ecosystem,with significant implications for carbon cycling in polar oceans.展开更多
During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest...During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.展开更多
Carbon fluxes are essential indicators assessing vegetation carbon cycle functions.However,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes ...Carbon fluxes are essential indicators assessing vegetation carbon cycle functions.However,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes in arid oasis and non-oasis area remains unclear.Here,we assessed and predicted the future effects of climate change and human activities on carbon fluxes in the Hexi Corridor.The results showed that the annual average gross primary productivity(GPP),net ecosystem productivity(NEP),and ecosystem respiration(Reco)in the Hexi Corridor oasis increased by 263.91 g C·m^(-2)·yr^(-1),118.45 g C·m^(-2)·yr^(-1)and 122.46 g C·m^(-2)·yr^(-1),respectively,due to the expansion of the oasis area by 3424.84 km^(2) caused by human activities from 2000 to 2022.Both oasis and non-oasis arid ecosystems in the Hexi Corridor acted as carbon sinks.Compared to the non-oasis area,the carbon fluxes contributions of oasis area increased,ranging from 10.21%to 13.99%for GPP,8.50%to11.68%for NEP,and 13.34%to 17.13%for Reco.The contribution of the carbon flux from the oasis expansion area to the total carbon flux change in the Hexi Corridor was 30.96%(7.09 Tg C yr^(-1))for GPP,29.57%(3.39 Tg C yr^(-1))for NEP and 32.40%(3.58 Tg C yr^(-1))for Reco.The changes in carbon fluxes in the oasis area were mainly attributed to human activities(oasis expansion)and temperature,whereas non-oasis area was mainly due to climate factors.Moreover,the future increasing trends were observed for GPP(64.99%),NEP(66.29%)and Reco(82.08%)in the Hexi Corridor.This study provides new insights into the regulatory mechanisms of carbon cycle in the arid oasis and non-oasis area.展开更多
To explore the relationship between dynamic characteristics and wake patterns,numerical simulations were conducted on three equal-diameter cylinders arranged in an equilateral triangle.The simulations varied reduced v...To explore the relationship between dynamic characteristics and wake patterns,numerical simulations were conducted on three equal-diameter cylinders arranged in an equilateral triangle.The simulations varied reduced velocities and gap spacing to observe flow-induced vibrations(FIVs).The immersed boundary–lattice Boltzmann flux solver(IB–LBFS)was applied as a numerical solution method,allowing for straightforward application on a simple Cartesian mesh.The accuracy and rationality of this method have been verified through comparisons with previous numerical results,including studies on flow past three stationary circular cylinders arranged in a similar pattern and vortex-induced vibrations of a single cylinder across different reduced velocities.When examining the FIVs of three cylinders,numerical simulations were carried out across a range of reduced velocities(3.0≤Ur≤13.0)and gap spacing(L=3D,4D,and 5D).The observed vibration response included several regimes:the desynchronization regime,the initial branch,and the lower branch.Notably,the transverse amplitude peaked,and a double vortex street formed in the wake when the reduced velocity reached the lower branch.This arrangement of three cylinders proved advantageous for energy capture as the upstream cylinder’s vibration response mirrored that of an isolated cylinder,while the response of each downstream cylinder was significantly enhanced.Compared to a single cylinder,the vibration and flow characteristics of this system are markedly more complex.The maximum transverse amplitudes of the downstream cylinders are nearly identical and exceed those observed in a single-cylinder set-up.Depending on the gap spacing,the flow pattern varied:it was in-phase for L=3D,antiphase for L=4D,and exhibited vortex shedding for L=5D.The wake configuration mainly featured double vortex streets for L=3D and evolved into two pairs of double vortex streets for L=5D.Consequently,it well illustrates the coupling mechanism that dynamics characteristics and wake vortex change with gap spacing and reduced velocities.展开更多
Global warming and nitrogen(N)deposition have a profound impact on greenhouse gas(GHG)fluxes and consequently,they also affect climate change.However,the global combined effects of warming and N addition on GHG fluxes...Global warming and nitrogen(N)deposition have a profound impact on greenhouse gas(GHG)fluxes and consequently,they also affect climate change.However,the global combined effects of warming and N addition on GHG fluxes remain to be fully understood.To address this knowledge gap,a globalmeta-analysis of 197 datasets was performed to assess the response of GHG fluxes to warming and N addition and their interactions under various climate and experimental conditions.The results indicate that warming significantly increased CO_(2)emissions,while N addition and the combined warming and N addition treatments had no impact on CO_(2)emissions.Moreover,both warming and N addition and their interactions exhibited positive effects on N_(2)O emissions.Under the combined warming and N addition treatments,warming was observed to exert a positive main effect on CO_(2)emissions,while N addition had a positive main effect on N_(2)O emissions.The interactive effects of warming and N addition exhibited antagonistic effects on CO_(2),N_(2)O,and CH_(4)emissions,with CH_(4)uptake dominated by additive effects.Furthermore,we identified biome and climate factors as the two treatments.These findings indicate that both warming and N addition substantially impact soil GHG fluxes and highlight the urgent need to investigate the influence of the combination of warming and N addition on terrestrial carbon and N cycling under ongoing global change.展开更多
This study investigates the inward flux events following sawtooth crashes in the edge of HL-2A neutral beam heated plasmas.We identified three distinct types of inward fluxes with varying magnitudes and durations,each...This study investigates the inward flux events following sawtooth crashes in the edge of HL-2A neutral beam heated plasmas.We identified three distinct types of inward fluxes with varying magnitudes and durations,each associated with unique plasma parameter fluctuations.Magnetic fluctuations,particularly the disruption of magnetic surface structures caused by sawtooth crashes,may play a significant role in modulating plasma dynamics.Moreover,the crossphase term and coherence between density and velocity fluctuations were found to be key factors in these flux events,with high coherence correlating with peak inward flux.These findings enhance the understanding of fluctuation-induced transport after sawtooth crashes and have implications for plasma confinement in fusion devices.展开更多
Peng et al.in[Phys.Rev.Research,2020,2(3):033089,11 pp.]formulated one-way fluxes for a general chemical reaction far from equilibrium,with arbitrary complex mechanisms,multiple intermediates,and internal kinetic cycl...Peng et al.in[Phys.Rev.Research,2020,2(3):033089,11 pp.]formulated one-way fluxes for a general chemical reaction far from equilibrium,with arbitrary complex mechanisms,multiple intermediates,and internal kinetic cycles.They defined the limit of the ratio of mesoscopic one-way fluxes and the volume of the tank reactor when the volume tends to infinity as macroscopic one-way fluxes,but a rigorous proof of existence of the limit is still awaiting.In this article,we fill this gap under a mild hypothesis:the Markov chain associated with the chemical master equation has finite states and any two columns in the stoichiometric matrices are not identical.In fact,an explicit expression of the limit is obtained.展开更多
The efficiency of energy conversion from mechanical to electrical in AC generators is not entirely optimal,as power losses are converted into heat.Accurate thermal modeling and temperature measurement of advanced elec...The efficiency of energy conversion from mechanical to electrical in AC generators is not entirely optimal,as power losses are converted into heat.Accurate thermal modeling and temperature measurement of advanced electric machines with complex structures are mandatory to confirm their reliability and safe operation.In a unique axial transverse flux switching permanent magnet(ATFSPM)generator,due to its high power density,large stray loss from leakage flux,compact topology,and totally enclosed structure,thermal analysis is of paramount significance.In this paper,thermal modeling and analysis of ATFSPM are carried out in detail using a three-dimensional(3D)finite element analysis(FEA)to evaluate the thermal condition for a precise performance improvement.To begin,all loss sources are accurately derived using 3-D FEA and analytical methods,taking into account the temperature dependence of material properties,and then losses are coupled to the thermal model as heat sources.Afterward,aiming for realistic thermal modelling,the convection heat transfer in the different regions of internal and external areas as well as thin layers of interface gaps between components are all considered.In addition,the prototype of ATFSPM is supplied to validate the accuracy of 3-D FEA temperature prediction.Furthermore,a novel technique is carried out to effectively improve thermal performance,enhance the efficiency,and limit hot-spot temperatures.The steady-state and transient temperature results demonstrate the high accuracy of the thermal modeling,enhance the secure operation of the ATFSPM,and facilitate increased loading utilizing the proposed technique.(1)展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52204345 and 52474361)the Scientific Research Innovation Projects of Graduate Student of Jiangsu province,China(No.KYCX24_4184)。
文摘The large-scale production of high-Ti steels is limited by the formation of Ti-containing oxides or nitrides in steel-slag reactions during continuous casting.These processes degrade mold flux properties,clog submerged entry nozzles,form floaters in the molds,and produce various surface defects on the cast slabs.This review summarizes the effects of nonmetallic inclusions on traditional CaO-SiO_(2)-based(CS)mold fluxes and novel CaO-Al_(2)O_(3)-based(CA)low-or non-reactive fluxes containing TiO_(2),BaO,and B_(2)O_(3)additives to avoid undesirable steel,slag,and inclusion reactions,with the aim of providing a new perspective for research and practice related to balancing the lubrication and heat transfer of mold fluxes to promote smooth operation and reduce surface defects on cast slabs.For traditional CS mold flux,although the addition of solvents such as Na_(2)O,Li_(2)O,and B_(2)O_(3)can enhance flowability,steel-slag reactions persist,limiting the effectiveness of CS mold fluxes in high-Ti steel casting.Low-or non-reactive CA mold fluxes with reduced SiO_(2)content are a research focus,where adding other components can significantly change flux characteristics.Replacing CaO with BaO can lower the melting point and inhibit crystallization,allowing the flux to maintain good flowability at low temperatures.Replacing SiO_(2)with TiO_(2)can stabilize the viscosity and enhance heat transfer.To reduce the environmental impact,fluorides are replaced with components such as TiO_(2),B_(2)O_(3),BaO,Li_(2)O,and Na_(2)O for F-frce mold fluxes with similar lubrication,crystallization,and heat-transfer effects.When TiO_(2)replaces CaF_(2),it stabilizes the viscosity and enhances the heat conductivity,forming CaTiO_(3)and CaSiTiO_(5)phases instead of cuspidine to control crystallization.B_(2)O_(3)lowers the melting point and suppresses crystallization,forming phases such as Ca_(3)B_(2)O_(6)and Ca_(11)Si_(4)B_(2)O_(22).BaO introduces non-bridging oxygen to reduce viscosity and ensure flux flowability at low temperatures.However,further studies are required to determine the optimal mold flux compositions corresponding to the steel grades and the interactions between the various components of the mold flux.In the future,the practical application of new mold fluxes for high-Ti steel will become the focus of further verification to achieve a balance between lubrication and heat transfer,which is expected to minimize the occurrence of casting problems and slab defects.
基金supported by the National Key Research and Development Program of China(No.2021YFC3201004)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2021ZT090543).
文摘Enhanced riverine nitrogen(N)and phosphorus(P)exports from anthropogenic activities have substantially increased primary productivity in downstream waters and induced harmful ecosystem effects.The components of riverine nutrient fluxes determine environmental responses that remain largely unknown.We identified different components of riverine N and P exports based on a load-hydrograph analysis of multiple sections of the Yangtze River in China based on long-term daily nutrient fluxes.Our results indicate that the increasing trend of riverine N and P fluxes from upstream to downstream can be reversed by the retention effect of dams and lakes,which is more significant for total phosphorus and its high-flux component than total nitrogen.The greatest nutrient retention along the river was mainly attributed to the Three Gorges Dam,which has a significant retention effect on both N and P fluxes,particularly on the high flux and TP.While high nutrient fluxes dominate upstream,middle and low fluxes dominate downstream.Significant but uncommon trends were observed for all nutrient flux components along the river.While both,medium and low flux percentages increase significantly,those of high flux decrease.The net change of N and P fluxes along the Yangtze River do not coincide in space,indicating heterogeneity between the river’s source and sink of N and P.Knowledge of the inconsistent alteration of riverine nutrient flux and its components should facilitate efforts to make better measures to mitigate nutrient-related problems in the Yangtze River.
基金financially supported by the National Key Research and Development Program of China(2021YFD2200405)the National Natural Science Foundation of China(31930078)special funds for Baotianman Forest Ecosystem Research Station from Chinese Academy of Forestry and Ministry of Science and Technology of China。
文摘Frequent droughts pose considerable threat to global forest carbon uptake,but little is known about the response of forest carbon fluxes in climatic transition zones to seasonal drought.In this study,the responses of carbon fluxes to seasonal drought in two natural forests(Quercus aliena var.acute serrata Maxim and Pinus tabuliformis Carr.)in the Baotianman Nature Reserve were investigated.The Q.aliena forest exhibited a high resilience with stable gross primary productivity(GPP).However,ecosystem respiration(Re)significantly declined by 18.4%compared with normal years,leading to an increase in net carbon sequestration capacity of 4.1%.This resilience was attributed to its deep root system accessing soil water(SWC_(50cm))to sustain stomatal openness,coupled with the efficient utilization of photosynthetically active radiation to drive photosynthesis.In contrast,the P.tabuliformis forest,which relied on shallow soil moisture(SWC_(20cm)),experienced simultaneous decreases in both GPP and Re during drought,with a sharply greater decrease in GPP,resulting in low net carbon sink capacity.Further analysis revealed that the Q.aliena forest prioritized carbon assimilation through a deep water-stomatal synergy strategy(anisohydric behavior),whereas the P.tabuliformis forest adopted an isohydric strategy favoring water conservation at the expense of carbon fixation efficiency.These findings highlight distinct mechanisms underlying drought adaptation between forest types,providing critical insight into optimizing forest carbon cycle models and selecting drought-resistant species under the influence of climate change.
文摘Synchronous reluctance motors(SynRM)are widely employed in industrial applications due to their high robustness,low cost,and absence of permanent magnets.In recent years,significant research efforts have focused on improving the controllability and efficiency of SynRM.Accurate rotor position information is essential for the controller to generate appropriate current and voltage references corresponding to the desired speed and load torque.Shaft-mounted position sensors are generally undesirable because of their high cost,sensitivity to harsh operating conditions,maintenance requirements,and reduced reliability in environments characterized by high vibration.Consequently,sensorless control techniques that estimate rotor position using measured stator currents and voltages have attracted increasing attention.However,magnetic saturation,parameter nonlinearities,and cross-coupling effects significantly degrade position estimation accuracy and may compromise the stability of sensorless SynRM drives.In this paper,a nonlinear SynRM model is developed using finite element analysis(FEA)to accurately capture magnetic saturation and cross-coupling effects,thereby providing a precise representation of the machine’s electromagnetic behavior under varying load and flux conditions.A series of magnetostatic FEA simulations is performed.To reduce computational complexity,only one motor pole is analyzed by applying anti-periodic boundary conditions along the domain sides and enforcing a zero magnetic vector potential on the external stator boundary.Nonlinear iron material properties are modeled using the appropriate B-H curve.The simulations are carried out by imposing d-and q-axis current components and computing the corresponding flux linkages and electromagnetic torque.Based on these results,both apparent and incremental inductances are extracted and incorporated into the control algorithm.An advanced fictitious flux linkage method combined with a phase-locked loop(PLL)is employed for accurate rotor position estimation.Simulation results confirm that the proposed sensorless control strategy ensures stable operation and high position estimation accuracy over the entire speed range.
文摘An atmospheric general circulation model(AGCM)is used to analyze the different impact on the Barents Sea(BS)and Greenland Sea(GS)for a perturbation of sea-to-air DMS flux.We compare contemporary anthropogenic S and contemporary DMS sea-to-air flux(as baseline,B00)sulfur emissions,with contemporary anthropogenic S and a perturbed DMS flux(as modified,B01)sulfur emissions.Results show that the global mean surface DMS and DMS vertically integrated concentration all peaked in June and increases more than 63%in BS and increases about 58%in GS.The concentrations of atmospheric sulfur dioxide vertical integral(SO_(2))and sulfate vertical integral(SO_(4))only increase less than 12%in both regions.Sulfur emission(SEM)peaked in June and increased about 67%and 41%in GS and BS,respectively.Aerosol optical depth(AOD)increases less than 4%in GS and in BS.Surface temperature(TSC)peaked in July and reduces 0.25 K and 0.8 K in GS and BS,respectively.Satellite data from 2003 to 2023show that chlorophyll(CHL)concentration in BS exceeds that of GS by 51%.The AOD in GS is only 0.6%higher than in BS.The recent increased rate of DMS surface concentration in BS(from 6%during 1981–2002 to 18.8%in 2003–2023)is mainly caused by elevated CHL concentrations in BS.Finally,the perturbation on DMS flux leads to increase rate of DMS and related sulfur emissions especially in the BS,this tendency will have an offsetting effect on regional warming.
文摘This paper proposes a collaborative design method for enhancing the power factor and torque of electric motors.First,the intrinsic relationship between flux linkage analysis of the permanent magnet(PM)and armature field and the power factor is explored.Then,the connection between flux linkage and harmonics is established,clarifying the mechanism for improving power factor and torque.Improvements are focused on the PM and permeance.Regarding the PM structure,employing a Y-shaped PM structure effectively increases PM utilization,reduces leakage flux at the outer ends,and enhances the PM flux linkage.Concerning permeance,stator tooth design is optimized to cooperatively improve permeance harmonics,reduce the non-working flux linkage of the armature field,and enhance the fundamental modulation wave of the armature field responsible for torque generation.This improves the power factor while maintaining motor torque.Finally,through PM structural design,the motor torque performance is optimized.Furthermore,the performance of the Y-shaped PM motor is evaluated.A prototype was manufactured and tested.Theoretical analysis and experimental results demonstrate the effectiveness of the proposed method to a significant extent.
基金supported by the National Natural Science Foundation of China(Nos.42371139,42201152)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(No.CUG240629)+2 种基金the“CUG Scholar”Scientific Research Funds at China University of Geosciences(Wuhan)(No.2023092)the Gansu Province Natural Science Foundation Key Project(No.23JRRA858)CAS President's International Fellowship for Visiting Scientists(No.2024PVC003)。
文摘The carbon cycle stands as a cornerstone among the Earth's material cycles,carrying profound implications for global climate dynamics and humanity's sustenance and advancement.Additionally,nitrogen,as a vital nutrient element,plays a pivotal role in biogeochemical processes,exerting significant influence on the ecological environment within watersheds.In this study,an analysis of the carbon(C)and nitrogen(N)components in the river water of 12 alpine basins on the eastern margin of the Tibetan Plateau(TP)reveals that the average dissolved organic carbon(DOC)concentration in the river water is 0.76±0.67 mg/L,indicating a lower level compared to the global river average organic carbon content.Specifically,the average DOC concentrations were 0.42±0.22 and 1.56±0.68 mg/L in the glacial and non-glacial basins,respectively.The average dissolved inorganic carbon(DIC)concentration in the eastern TP is 27.04±20.19 mg/L,with the lowest DIC observed at Dagu Glacier and the highest at Daxia River.Furthermore,the average dissolved total carbon(DTC)concentration in glacier river water was 18.87±12.65 mg/L,contrasting with 48.23±21.07 mg/L in non-glacial basins.The mean concentration of total nitrogen(TN)in the eastern TP averaged 0.97±0.54 mg/L,with the glacial basin registering 1.01±0.47 mg/L and the non-glacial basin at 0.89±0.70 mg/L.Evaluating the release fluxes of carbon and nitrogen across 12 river basins revealed a range of DTC emission fluxes from 0.32×10^(9)to 31.02×10^(9)g·C/a,with inorganic carbon comprising 71.0%to 99.5%.Consequently,the carbon emission flux for seven glacier basins totaled 15.91×10^(9)g·C/a,while for the five non-glacial river basins,it reached 87.37×10^(9)g·C/a.The total TN release fluxes across 12 small river basins amounted to 2.46×10^(9)g·N/a,with 0.84×10^(9)g·N/a released in glacial basins and 1.62×10^(9)g·N/a in the nonglacial basin.This study elucidates the spatial distribution and transport mechanisms of carbon and nitrogen elements within the glacial and downstream non-glacial basins,offering valuable insights into the biogeochemical cycles of carbon and nitrogen in the eastern Tibetan Plateau.
文摘Correction to:Journal of Forestry Research(2025)36:124 https://doi.org/10.1007/s11676-025-01918-8 In this article the author’s name Yasutomo Hoshika was incorrectly written as Yasutoma Hoshika.The original article has been corrected.
基金supported by the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2023QN04011)the National Natural Science Foundation of China(Nos.42307092 and 52279067)+1 种基金Ordos Science and Technology Major Project(No.ZD20232303)Project of Key Laboratory of River and Lake in Inner Mongolia Autonomous Region(No.2022QZBZ0003).
文摘Lacustrine groundwater discharge(LGD)plays an important role in water resources management.Previous studies have focused on LGD process in a single lake,but the differences in LGD process within the same region have not been thoroughly investigated.In this study,multiple tracers(hydrochemistry,𝛿D,𝛿18O and 222Rn)were used to compare mechanisms of LGD in Daihai and Ulansuhai Lake in Inner Mongoli1,Northwest China.The hydrochemical types showed a trend from groundwater to lake water,indicating a hydraulic connection between them.In addition,the𝛿D and𝛿18O values of sediment pore water were between the groundwater and lake water,indicating the LGD processes.The radon mass balance model was used to estimate the average groundwater discharge rates of Daihai and Ulansuhai Lake,which were 2.79 mm/day and 3.02 mm/day,respectively.The total nitrogen(TN),total phosphorus(TP),and fluoride inputs associated with LGD in Daihai Lake accounted for 97.52%,96.59%,and 95.84%of the total inputs,respectively.In contrast,TN,TP and fluoride inputs in Ulansuhai Lake were 53.56%,40.98%,and 36.25%,respectively.This indicates that the pollutant inputs associated with LGD posed a potential threat to the ecological stability of Daihai and Ulansuhai Lake.By comparison,the differences of LGD process and associated pollutant flux were controlled by hydrogeological conditions,lakebed permeability and human activities.This study provides a reference for water resources management in Daihai and Ulansuhai Lake basins while improving the understanding of LGD in the Yellow River basin.
文摘Plant aggregate-based building materials are a viable solution for reducing greenhouse gas emissions and providing good thermal and acoustic performances.In this study,the investigated lightweight mortars require a hydraulic reaction.Laboratory and on-site empirical observations about plant aggregate-based materials indicate a delay in setting time and a decrease in the mechanical performances of concretes based on plant aggregates.The natural origin of plant-aggregates causes a lot of variability in their properties.Related studies have shown that the incompatibility between plant aggregates and cement is mainly caused by the dissolved and decomposed components of plant aggregates in alkaline environments.Currently,no research on the specific impact of each component on the setting time of lime-based binder exists.In this work,the impact of some soluble compounds(e.g.,sucrose,glucose,fructose,pectin)on the setting reaction of the lime matrix was studied using Vicat test,thermogravimetric analysis(TGA)and FT-IR spectroscopy.Experimental results showed that carbohydrates such as glucose and sucrose not only affect the setting time but also have a long-term impact on the carbonation of lime.The measure of the setting time by Vicat test appears as a possible indicator to predict the compatibility between the matrix and plant aggregates.
基金The National Key Research and Development Program of China under contract No.2022YFE0136500the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,under contract Nos JG2212 and JG2211+2 种基金the National Natural Science Foundation of China under contract Nos 42276255,41976228,and 42176227the National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”under contract Nos IRASCC 01-01-02 and IRASCC 02-02the China Scholarship Council under contract No.201704180017.
文摘The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of variability in the timing of seasonal sea ice retreat on the flux and composition of sinking particulate matter remains to be elucidated.In this study,we deployed sediment traps in Prydz Bay during the austral summers of 2019/2020 and 2020/2021,noting that sea ice melting occurred approximately one and a half months earlier in the former summer compared to the latter.We analyzed sediment trap data,which included total mass flux(TMF),particulate organic carbon(POC),biogenic silica(BSi),particulate inorganic carbon,and lithogenic particle(Litho)fluxes,as well as the stable isotopesδ^(13)C andδ^(15)N of particulate organic matter(POM).Additionally,we incorporated remote sensing data on sea ice concentration and chlorophyll a.This dramatic delay in sea ice melting timing could result in a significant increase in TMF,BSi and POC fluxes in the summer of 2020/2021 compared to 2019/2020.Elevated BSi fluxes and more ^(13)C-depleted POC in the austral summer of 2020/2021 suggest that the delayed melting of sea ice may have stimulated the productivity of centric diatoms.Furthermore,the higher BSi/POC ratio and more negativeδ^(15)N values of POM,along with a reduced presence of krill in the traps,indicate a diminished grazing pressure from zooplankton,which collectively enhanced the sedimentation efficiency of POC during the austral summer of 2020/2021.These findings highlight the critical role of sea ice melting timing in regulating productivity,flux and composition of sinking particulate matter in the Prydz Bay ecosystem,with significant implications for carbon cycling in polar oceans.
基金financially supported by the National Natural Science Foundation of China(Nos.52274315 and 52374320)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-22-011A1 and FRF-DF22-16)。
文摘During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.
基金The Foundation for Distinguished Young Scholars of Gansu Province,No.22JR5RA046Key Research Program of Gansu Province,No.23ZDKA0004+2 种基金The Joint Funds of the National Natural Science Foundation of China,No.U22A202690Interdisciplinary Youth Team Project from the Key Laboratory of Cryospheric Science and Frozen Soil Engineering,No.CSFSE-ZQ-2408The Youth Innovation Promotion Association CAS to X.W.,No.2020422。
文摘Carbon fluxes are essential indicators assessing vegetation carbon cycle functions.However,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes in arid oasis and non-oasis area remains unclear.Here,we assessed and predicted the future effects of climate change and human activities on carbon fluxes in the Hexi Corridor.The results showed that the annual average gross primary productivity(GPP),net ecosystem productivity(NEP),and ecosystem respiration(Reco)in the Hexi Corridor oasis increased by 263.91 g C·m^(-2)·yr^(-1),118.45 g C·m^(-2)·yr^(-1)and 122.46 g C·m^(-2)·yr^(-1),respectively,due to the expansion of the oasis area by 3424.84 km^(2) caused by human activities from 2000 to 2022.Both oasis and non-oasis arid ecosystems in the Hexi Corridor acted as carbon sinks.Compared to the non-oasis area,the carbon fluxes contributions of oasis area increased,ranging from 10.21%to 13.99%for GPP,8.50%to11.68%for NEP,and 13.34%to 17.13%for Reco.The contribution of the carbon flux from the oasis expansion area to the total carbon flux change in the Hexi Corridor was 30.96%(7.09 Tg C yr^(-1))for GPP,29.57%(3.39 Tg C yr^(-1))for NEP and 32.40%(3.58 Tg C yr^(-1))for Reco.The changes in carbon fluxes in the oasis area were mainly attributed to human activities(oasis expansion)and temperature,whereas non-oasis area was mainly due to climate factors.Moreover,the future increasing trends were observed for GPP(64.99%),NEP(66.29%)and Reco(82.08%)in the Hexi Corridor.This study provides new insights into the regulatory mechanisms of carbon cycle in the arid oasis and non-oasis area.
基金Supported by the National Natural Science Foundation of China(52201350,52201394,and 52271301)the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2022008).
文摘To explore the relationship between dynamic characteristics and wake patterns,numerical simulations were conducted on three equal-diameter cylinders arranged in an equilateral triangle.The simulations varied reduced velocities and gap spacing to observe flow-induced vibrations(FIVs).The immersed boundary–lattice Boltzmann flux solver(IB–LBFS)was applied as a numerical solution method,allowing for straightforward application on a simple Cartesian mesh.The accuracy and rationality of this method have been verified through comparisons with previous numerical results,including studies on flow past three stationary circular cylinders arranged in a similar pattern and vortex-induced vibrations of a single cylinder across different reduced velocities.When examining the FIVs of three cylinders,numerical simulations were carried out across a range of reduced velocities(3.0≤Ur≤13.0)and gap spacing(L=3D,4D,and 5D).The observed vibration response included several regimes:the desynchronization regime,the initial branch,and the lower branch.Notably,the transverse amplitude peaked,and a double vortex street formed in the wake when the reduced velocity reached the lower branch.This arrangement of three cylinders proved advantageous for energy capture as the upstream cylinder’s vibration response mirrored that of an isolated cylinder,while the response of each downstream cylinder was significantly enhanced.Compared to a single cylinder,the vibration and flow characteristics of this system are markedly more complex.The maximum transverse amplitudes of the downstream cylinders are nearly identical and exceed those observed in a single-cylinder set-up.Depending on the gap spacing,the flow pattern varied:it was in-phase for L=3D,antiphase for L=4D,and exhibited vortex shedding for L=5D.The wake configuration mainly featured double vortex streets for L=3D and evolved into two pairs of double vortex streets for L=5D.Consequently,it well illustrates the coupling mechanism that dynamics characteristics and wake vortex change with gap spacing and reduced velocities.
基金supported by Ningxia Key Research and Development Fund Project of China(No.2023BCF01048)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-YB-182).
文摘Global warming and nitrogen(N)deposition have a profound impact on greenhouse gas(GHG)fluxes and consequently,they also affect climate change.However,the global combined effects of warming and N addition on GHG fluxes remain to be fully understood.To address this knowledge gap,a globalmeta-analysis of 197 datasets was performed to assess the response of GHG fluxes to warming and N addition and their interactions under various climate and experimental conditions.The results indicate that warming significantly increased CO_(2)emissions,while N addition and the combined warming and N addition treatments had no impact on CO_(2)emissions.Moreover,both warming and N addition and their interactions exhibited positive effects on N_(2)O emissions.Under the combined warming and N addition treatments,warming was observed to exert a positive main effect on CO_(2)emissions,while N addition had a positive main effect on N_(2)O emissions.The interactive effects of warming and N addition exhibited antagonistic effects on CO_(2),N_(2)O,and CH_(4)emissions,with CH_(4)uptake dominated by additive effects.Furthermore,we identified biome and climate factors as the two treatments.These findings indicate that both warming and N addition substantially impact soil GHG fluxes and highlight the urgent need to investigate the influence of the combination of warming and N addition on terrestrial carbon and N cycling under ongoing global change.
基金support of these experiments.This work was supported by the National Natural Science Foundation of China(12405268,12175227,11875255,12375226,and 11975231)the National Magnetic Confinement Fusion Science Program of China(2022YFE03060003,2022YFE03100004)+1 种基金the Fundamental Research Funds for the Central Universities(WK2140000016)the China Postdoctoral Science Foundation(2022M723066).
文摘This study investigates the inward flux events following sawtooth crashes in the edge of HL-2A neutral beam heated plasmas.We identified three distinct types of inward fluxes with varying magnitudes and durations,each associated with unique plasma parameter fluctuations.Magnetic fluctuations,particularly the disruption of magnetic surface structures caused by sawtooth crashes,may play a significant role in modulating plasma dynamics.Moreover,the crossphase term and coherence between density and velocity fluctuations were found to be key factors in these flux events,with high coherence correlating with peak inward flux.These findings enhance the understanding of fluctuation-induced transport after sawtooth crashes and have implications for plasma confinement in fusion devices.
基金partially supported by NSFC(Nos.11701265,11961033).
文摘Peng et al.in[Phys.Rev.Research,2020,2(3):033089,11 pp.]formulated one-way fluxes for a general chemical reaction far from equilibrium,with arbitrary complex mechanisms,multiple intermediates,and internal kinetic cycles.They defined the limit of the ratio of mesoscopic one-way fluxes and the volume of the tank reactor when the volume tends to infinity as macroscopic one-way fluxes,but a rigorous proof of existence of the limit is still awaiting.In this article,we fill this gap under a mild hypothesis:the Markov chain associated with the chemical master equation has finite states and any two columns in the stoichiometric matrices are not identical.In fact,an explicit expression of the limit is obtained.
基金supported by research grants of the Iran National Science Foundation(INSF)under grant No.98002866。
文摘The efficiency of energy conversion from mechanical to electrical in AC generators is not entirely optimal,as power losses are converted into heat.Accurate thermal modeling and temperature measurement of advanced electric machines with complex structures are mandatory to confirm their reliability and safe operation.In a unique axial transverse flux switching permanent magnet(ATFSPM)generator,due to its high power density,large stray loss from leakage flux,compact topology,and totally enclosed structure,thermal analysis is of paramount significance.In this paper,thermal modeling and analysis of ATFSPM are carried out in detail using a three-dimensional(3D)finite element analysis(FEA)to evaluate the thermal condition for a precise performance improvement.To begin,all loss sources are accurately derived using 3-D FEA and analytical methods,taking into account the temperature dependence of material properties,and then losses are coupled to the thermal model as heat sources.Afterward,aiming for realistic thermal modelling,the convection heat transfer in the different regions of internal and external areas as well as thin layers of interface gaps between components are all considered.In addition,the prototype of ATFSPM is supplied to validate the accuracy of 3-D FEA temperature prediction.Furthermore,a novel technique is carried out to effectively improve thermal performance,enhance the efficiency,and limit hot-spot temperatures.The steady-state and transient temperature results demonstrate the high accuracy of the thermal modeling,enhance the secure operation of the ATFSPM,and facilitate increased loading utilizing the proposed technique.(1)
