Interfering with the ferroptosis pathway is a new strategy for the treatment of spinal cord injury.Fibroblast growth factor 21 can inhibit ferro ptosis and promote neurofunctional recovery,while heme oxygenase-1 is a ...Interfering with the ferroptosis pathway is a new strategy for the treatment of spinal cord injury.Fibroblast growth factor 21 can inhibit ferro ptosis and promote neurofunctional recovery,while heme oxygenase-1 is a regulator of iron and reactive oxygen species homeostasis.The relationship between heme oxygenase-1and ferroptosis remains controve rsial.In this study,we used a spinal co rd injury rat model to show that the levels of fibroblast growth factor 21 in spinal co rd tissue decreased after spinal cord injury.In addition,there was a significant aggravation of ferroptosis and a rapid increase in heme oxygenase-1 expression after spinal cord injury.Furthe r,heme oxygenase-1 aggravated fe rroptosis after spinal cord injury,while fibroblast growth factor 21 inhibited fe rroptosis by downregulating heme oxygenase-1.Thus,the activation of fibroblast growth factor 21 may provide a potential treatment for spinal co rd injury.These findings could provide a new potential mechanistic explanation for fibroblast growth factor 21 in the treatment of spinal cord injury.展开更多
Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary productivity.The satellite observations show that the norther...Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary productivity.The satellite observations show that the northern Arafura Sea(NAS),especially in the coastal region,features high chlorophyll-a(chl-a)concentrations,implying a strong coastal upwelling.However,coastal upwelling in the NAS has not received much attention.Based on a semi-automatic image processing technology,the seasonal and interannual variability of coastal upwelling in the NAS are investigated in this study using satellite-observed sea surface temperature(SST)and wind data.The results suggest that there are seasonal coastal upwelling events in the NAS modulated by upwelling-favorable southeast monsoon(SEM).The annual mean days,mean area,and annual mean intensity of coastal upwelling events during the SEM season are 92 days,6514 km^(2),and-5.31×10^(5),respectively,while the corresponding values during the northwest monsoon(NWM)season are 32 days,5569 km^(2),and-1.41×10^(5).It is also found that the SEM coastal upwelling in the NAS displays prominent interannual variability.The strong upwelling events are found in 2010,2013,2016,and 2017 when the southeast monsoon winds were weaker.Further analysis suggests that at the interannual scale,the upwelling index(UI)averaged in the SEM season is negatively correlated with that of three upwelling indicators.This can be attributed to the limitation of onshore geostrophic flow which is evidenced by the negative correlation between the UI and the alongshore difference in sea surface height.This study highlights the important role of the southeast monsoon in the temporal variability of coastal upwelling in the NAS.展开更多
Accurately predicting the production rate and estimated ultimate recovery(EUR)of shale oil wells is vital for efficient shale oil development.Although numerical simulations provide accurate predictions,their high time...Accurately predicting the production rate and estimated ultimate recovery(EUR)of shale oil wells is vital for efficient shale oil development.Although numerical simulations provide accurate predictions,their high time,data,and labor demands call for a swifter,yet precise,method.This study introduces the DuongeCNNeLSTM(D-C-L)model,which integrates a convolutional neural network(CNN)with a long short-term memory(LSTM)network and is grounded on the empirical Duong model for physical constraints.Compared to traditional approaches,the D-C-L model demonstrates superior precision,efficiency,and cost-effectiveness in predicting shale oil production.展开更多
Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding re...Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.展开更多
Layer-structured Shsse attracts much attention as an anode material for potassium storage due to its la rge theoretical capacity.Unfortunately,their practical application is severely restrained by the dramatic volumet...Layer-structured Shsse attracts much attention as an anode material for potassium storage due to its la rge theoretical capacity.Unfortunately,their practical application is severely restrained by the dramatic volumetric variation of SnSSe.Herein,we synthesize ultrafine SnSSe/multilayer graphene nanosheet(SnSSe/MGS) by a vacuum solid-phase reaction and subsequent ball milling.Owing to the strong synergistic effect between the two components,the obtained SnSSe/MGS nanocomposite exhibits a high reversible capacity(423 mAh g^(-1) at 100 mA g^(-1)),excellent rate property(218 mAh g^(-1) at 5 A g^(-1)),and stable cycling performance(271 mAh g^(-1) after 500 cycles at 100 mA g^(-1)) in potassium-ion half batteries.Moreover,the full cell assembled by the SnSSe/MGS anode and the potassiated 3,4,9,10-perylene-tetracar boxylic aciddianhydride cathode shows excellent electrochemical performance between 0.2 and 3.3 V(209 mAh g^(-1) at 50 mA g^(-1) after 100 cycles).The presented two-step synthesis strategy of SnSSe/MGS may also provide ideas to craft other alloy-type anode materials.展开更多
Upper ocean mixing plays a key role in the atmosphere-ocean heat transfer and sea ice extent and thickness via modulating the upper ocean temperatures in the Arctic Ocean.Observations of diffusivities in the Arctic th...Upper ocean mixing plays a key role in the atmosphere-ocean heat transfer and sea ice extent and thickness via modulating the upper ocean temperatures in the Arctic Ocean.Observations of diffusivities in the Arctic that directly indicate the ocean mixing properties are sparse.Therefore,the spatiotemporal pattern and magnitude of diapycnal diffusivities and kinetic energy dissipation rates in the upper Arctic Ocean are important for atmosphere-ocean heat transfers and sea ice changes.These were first estimated from the Ice-Tethered Profilers dataset(2005–2019)using a strain-based fine-scale parameterization.The resultant mixing properties showed signifi cant geographical inhomogeneity and temporal variability.Diapycnal diff usivities and dissipation rates in the Atlantic sector of the Arctic Ocean were stronger than those on the Pacific side.Mixing in the Atlantic sector increased significantly during the observation period;whereas in the Pacific sector,it weakened before 2011 and then strengthened.Potential impact factors include wind,sea ice,near inertial waves,and stratifi cation,while their relative contributions vary between the two sectors of the Arctic Ocean.In the Atlantic sector,turbulent mixing dominated,while in the Pacific sector,turbulent mixing was inhibited by strong stratification prior to 2011,and is able to overcome the stratifi cation gradually after 2014.The vertical turbulent heat fl ux constantly increased in the Atlantic sector year by year,while it decreased in the Pacific sector post 2010.The estimated heat flux variability induced by enhanced turbulent mixing is expected to continue to diminish sea ice in the near future.展开更多
The problem of distributed detection fusion using multiple sensors for remote underwater target detection is studied. Considering that multiple access channel （MAC） schemes are able to offer high efficiency in bandw...The problem of distributed detection fusion using multiple sensors for remote underwater target detection is studied. Considering that multiple access channel （MAC） schemes are able to offer high efficiency in bandwidth usage and consume less energy than the parallel access channel （PAC）, the MAC scheme is introduced into the underwater target detection field. The model of underwater distributed detection fusion based on MAC schemes is established. A new method for detection fusion of MAC based on deflection coefficient maximization （DCM） and Neyman-Pearson （NP） rule is proposed. Under the power constraint of local sensors, this paper uses the DCM theory to derive the optimal weight coefficients and offsets. The closed-form expressions of detection probability and false alarm probability for fusion systems are obtained. The optimal detection performance of fusion systems is analyzed and deeply researched. Both the theory analysis and simulation experiments indicate that the proposed method could improve the detection performance and decrease the error probability effectively under power constraints of local sensors and low signal to noise ratio.展开更多
A series of non-hydrostatic,non-linear numerical simulations were carried out to investigate the generation and evolution of internal solitary waves(ISWs)through the interaction of a barotropic tidal current with an i...A series of non-hydrostatic,non-linear numerical simulations were carried out to investigate the generation and evolution of internal solitary waves(ISWs)through the interaction of a barotropic tidal current with an ice keel in the Arctic Ocean.During the interaction process,the internal surge was generated at first,and then the wave gradually steepened due to non-linearity during its propagation away from the ice keel.The internal surge eventually disintegrated into multi-modal and rank-ordered ISW packets with the largest having an amplitude of O(10)m.Sensitivity experiments demonstrated that the ISWs’amplitudes and energy were proportional to the varying ice keel depths and barotropic tidal fl ow amplitudes,but were insensitive to the changing ice keel widths.Typical ISWs can enhance the turbulent dissipation rate of O(10^(-6))W/kg along their propagation path.Further,heat entrainment induced by the wave-ice interaction can reach O(10)MJ/m per tidal cycle.This study reveals a particular ISW generation mechanism and process in the polar ice environment,which could be important in impacting the energy transfer and heat balance in the Arctic Ocean.展开更多
This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated i...This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated in isolated state are identified. Second, different schemes are proposed for generator mode switching from on-grid to off-grid state through comparison and mechanism analysis. Third, the time domain model and frequency domain model of the isolated generator governor are constructed to respectively estimate the primary frequency performance and small signal stability. Parameter sets that satisfy the primary frequency performance and small signal stability are acquired as optimal values of governor control parameters. Finally, the measurement-based parameters of the governor are identified and validated using simulations to demonstrate the feasibility and effectiveness of the method.展开更多
The generation and propagation characteristics of near-inertial waves(NIWs)generated spontaneously from a quasi-geostrophic anticyclonic mesoscale eddy in a rotating and stratifi ed fl uid were investigated by three-d...The generation and propagation characteristics of near-inertial waves(NIWs)generated spontaneously from a quasi-geostrophic anticyclonic mesoscale eddy in a rotating and stratifi ed fl uid were investigated by three-dimensional numerical modeling.NIWs are generated over a long time interval as a forced response to balanced baroclinic mesoscale eddies.For such eddies,NIW generation from balanced flow is an inevitable result as the evolution of eddies.Moreover,the baroclinicity of mesoscale eddies is an essential condition for this NIW generation mechanism.The spontaneously generated NIWs radiate horizontally toward the eddy center and propagate upward in vertical direction.The forcing of the NIWs moves downward along the eddy axis from the location of maximum temperature anomaly of the mesoscale eddy.The moving speed of the forcing is independent on the balanced mesoscale eddies but is determined by the ratio of buoyancy to inertial frequency.When the forcing reaches the bottom of the mesoscale eddy,the spontaneous NIW generation process terminates.NIW intensity in this spontaneous generation process is strengthened with the increase of the Rossby and Froude numbers.Further research to gain a solid understanding of the role of the Rossby and Froude numbers is necessary for the parameterization of spontaneous NIW generation from quasi-geostrophic mesoscale eddies in general circulation model.展开更多
Acid-catalyzed tandem reactions were established by employing a novel class of 2-arylglycerol derivative,5-aryl-1,3-dioxan-5-ol,as versatile 1,3-biselectrophile.In the reactions,5-aryl-1,3-dioxan-5-ol works like atrop...Acid-catalyzed tandem reactions were established by employing a novel class of 2-arylglycerol derivative,5-aryl-1,3-dioxan-5-ol,as versatile 1,3-biselectrophile.In the reactions,5-aryl-1,3-dioxan-5-ol works like atropaldehydes or 2-aryl malondialdehydes,and can react with 2-naphthols andβ-keto amides,allowing the synthesis of 4H-chromenes and 5-aryl-2-pyridinones.High yields,good functional group tolerance,broad substrate scope and simple reaction operation make this protocol attractive.展开更多
Cancer cells are abnormal cells that can reproduce and regenerate rapidly.They are characterized by unlimited proliferation,transformation and migration,and can destroy normal cells.To meet the needs for cell prolifer...Cancer cells are abnormal cells that can reproduce and regenerate rapidly.They are characterized by unlimited proliferation,transformation and migration,and can destroy normal cells.To meet the needs for cell proliferation and migration,tumor cells acquire molecular materials and energy through unusual metabolic pathways as their metabolism is more vigorous than that of normal cells.Multiple carcinogenic signaling pathways eventually converge to regulate three major metabolic pathways in tumor cells,including glucose,lipid,and amino acid metabolism.The distinct metabolic signatures of cancer cells reflect that metabolic changes are indispensable for the genesis and development of tumor cells.In this review,we report the unique metabolic alterations in tumor cells which occur through various signaling axes,and present various modalities available for cancer diagnosis and clinical therapy.We further provide suggestions for the development of anti-tumor therapeutic drugs.展开更多
OBJECTIVE:To compare the curative effects of heat-sensitive moxibustion with conventional drugs on chronic persistent asthma and seek a valuable therapy to replaceWestern Medicine.METHODS:The participants in this mult...OBJECTIVE:To compare the curative effects of heat-sensitive moxibustion with conventional drugs on chronic persistent asthma and seek a valuable therapy to replaceWestern Medicine.METHODS:The participants in this multi-center,randomized,and controlled study were randomly divided into two groups:group A(n=144),treated with heat-sensitive moxibustion(50 sessions)and group B(n=144),treated with Seretide(salmeterol50μg/fluticasone 250μg,twice a day).The scores of asthma control test(ACT),forced expiratory volume in 1 second(FEV1),peak expiratory flow(PEF),and attack frequency were measured after 15,30,60,and 90 days of treatment.Patients followed up3 and 6 months after treatment.RESULTS:There was a significant difference(P=0.0002)in the ACT score and lung function between the two groups after 3 months of treatment and(P=0.000 03)during the follow-up visits.In addition,heat-sensitive moxibustion reduced attack frequency in the period from inclusion to the6-month follow-up visit.CONCLUSION:This study shows that heat-sensitive moxibustion may have a comparable curative effect toSeretide(salmeterol/fluticasone)on asthma.展开更多
A facile copper-based catalytic system has been developed to enable efficient cyclization of methylketoximes and alkynals.This protocol provides a viable entry to synthetically and pharmaceutically useful 2-acylpyrrol...A facile copper-based catalytic system has been developed to enable efficient cyclization of methylketoximes and alkynals.This protocol provides a viable entry to synthetically and pharmaceutically useful 2-acylpyrroles with a broad range of compatible functionalities.Mechanistically,a key acyl migration is probably involved that leads to the formation of N-acyl pyrroles or otherwise NH pyrroles by further hydrolysis.More importantly,the present reaction system also gives an opportunity to realize three-component pyrrole assembly by simple addition of carboxylic acid.展开更多
基金supported by grants from Jiangsu Commission of Health,No.Z2021086(to XL)Science and Technology Program of Suzhou,Nos.SYSD2020008(to XL),SKYD2022012(to XL)+1 种基金Suzhou Municipal Health Commission,No.KJXW2020058(to XL)Science and Technology Program of Zhangjiagang,No.ZKS2018(to XL)。
文摘Interfering with the ferroptosis pathway is a new strategy for the treatment of spinal cord injury.Fibroblast growth factor 21 can inhibit ferro ptosis and promote neurofunctional recovery,while heme oxygenase-1 is a regulator of iron and reactive oxygen species homeostasis.The relationship between heme oxygenase-1and ferroptosis remains controve rsial.In this study,we used a spinal co rd injury rat model to show that the levels of fibroblast growth factor 21 in spinal co rd tissue decreased after spinal cord injury.In addition,there was a significant aggravation of ferroptosis and a rapid increase in heme oxygenase-1 expression after spinal cord injury.Furthe r,heme oxygenase-1 aggravated fe rroptosis after spinal cord injury,while fibroblast growth factor 21 inhibited fe rroptosis by downregulating heme oxygenase-1.Thus,the activation of fibroblast growth factor 21 may provide a potential treatment for spinal co rd injury.These findings could provide a new potential mechanistic explanation for fibroblast growth factor 21 in the treatment of spinal cord injury.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB 42000000)the National Natural Science Foundation of China(No.92258301)+2 种基金the Scientific and Technological Innovation Project financially supported by Laoshan Laboratory(No.LSKJ202202502)the CAS Key Deployment Project of Center for Ocean Mega-Research of Science(No.COMS2020Q07)the CAS-CSIRO Jointly Project(No.133244KYSB20190031)。
文摘Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary productivity.The satellite observations show that the northern Arafura Sea(NAS),especially in the coastal region,features high chlorophyll-a(chl-a)concentrations,implying a strong coastal upwelling.However,coastal upwelling in the NAS has not received much attention.Based on a semi-automatic image processing technology,the seasonal and interannual variability of coastal upwelling in the NAS are investigated in this study using satellite-observed sea surface temperature(SST)and wind data.The results suggest that there are seasonal coastal upwelling events in the NAS modulated by upwelling-favorable southeast monsoon(SEM).The annual mean days,mean area,and annual mean intensity of coastal upwelling events during the SEM season are 92 days,6514 km^(2),and-5.31×10^(5),respectively,while the corresponding values during the northwest monsoon(NWM)season are 32 days,5569 km^(2),and-1.41×10^(5).It is also found that the SEM coastal upwelling in the NAS displays prominent interannual variability.The strong upwelling events are found in 2010,2013,2016,and 2017 when the southeast monsoon winds were weaker.Further analysis suggests that at the interannual scale,the upwelling index(UI)averaged in the SEM season is negatively correlated with that of three upwelling indicators.This can be attributed to the limitation of onshore geostrophic flow which is evidenced by the negative correlation between the UI and the alongshore difference in sea surface height.This study highlights the important role of the southeast monsoon in the temporal variability of coastal upwelling in the NAS.
基金funded by the National Natural Science Foundation of China(No.51974356).
文摘Accurately predicting the production rate and estimated ultimate recovery(EUR)of shale oil wells is vital for efficient shale oil development.Although numerical simulations provide accurate predictions,their high time,data,and labor demands call for a swifter,yet precise,method.This study introduces the DuongeCNNeLSTM(D-C-L)model,which integrates a convolutional neural network(CNN)with a long short-term memory(LSTM)network and is grounded on the empirical Duong model for physical constraints.Compared to traditional approaches,the D-C-L model demonstrates superior precision,efficiency,and cost-effectiveness in predicting shale oil production.
基金supported by the Key Research and Development Program of Hebei Province[20326333D]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2019]001]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2020]013]。
文摘Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.
基金supported by the National Natural Science Foundation of China (22075147)the Natural Science Foundation of Jiangsu Province of China (BK20180086)。
文摘Layer-structured Shsse attracts much attention as an anode material for potassium storage due to its la rge theoretical capacity.Unfortunately,their practical application is severely restrained by the dramatic volumetric variation of SnSSe.Herein,we synthesize ultrafine SnSSe/multilayer graphene nanosheet(SnSSe/MGS) by a vacuum solid-phase reaction and subsequent ball milling.Owing to the strong synergistic effect between the two components,the obtained SnSSe/MGS nanocomposite exhibits a high reversible capacity(423 mAh g^(-1) at 100 mA g^(-1)),excellent rate property(218 mAh g^(-1) at 5 A g^(-1)),and stable cycling performance(271 mAh g^(-1) after 500 cycles at 100 mA g^(-1)) in potassium-ion half batteries.Moreover,the full cell assembled by the SnSSe/MGS anode and the potassiated 3,4,9,10-perylene-tetracar boxylic aciddianhydride cathode shows excellent electrochemical performance between 0.2 and 3.3 V(209 mAh g^(-1) at 50 mA g^(-1) after 100 cycles).The presented two-step synthesis strategy of SnSSe/MGS may also provide ideas to craft other alloy-type anode materials.
基金Supported by the National Key Research and Development Program of China(Nos.2019YFE0105700,2017YFA0604102)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB42000000,XDA22050202)+2 种基金the National Natural Science Foundation of China(Nos.92058202,41676006,42176244)the Key Deployment Project of Centre for Ocean Mega-Research of Science,Chinese Academy of Sciences(No.COMS2020Q07)the CAS-CSIRO Jointly MHW Project(No.133244KYSB20190031)。
文摘Upper ocean mixing plays a key role in the atmosphere-ocean heat transfer and sea ice extent and thickness via modulating the upper ocean temperatures in the Arctic Ocean.Observations of diffusivities in the Arctic that directly indicate the ocean mixing properties are sparse.Therefore,the spatiotemporal pattern and magnitude of diapycnal diffusivities and kinetic energy dissipation rates in the upper Arctic Ocean are important for atmosphere-ocean heat transfers and sea ice changes.These were first estimated from the Ice-Tethered Profilers dataset(2005–2019)using a strain-based fine-scale parameterization.The resultant mixing properties showed signifi cant geographical inhomogeneity and temporal variability.Diapycnal diff usivities and dissipation rates in the Atlantic sector of the Arctic Ocean were stronger than those on the Pacific side.Mixing in the Atlantic sector increased significantly during the observation period;whereas in the Pacific sector,it weakened before 2011 and then strengthened.Potential impact factors include wind,sea ice,near inertial waves,and stratifi cation,while their relative contributions vary between the two sectors of the Arctic Ocean.In the Atlantic sector,turbulent mixing dominated,while in the Pacific sector,turbulent mixing was inhibited by strong stratification prior to 2011,and is able to overcome the stratifi cation gradually after 2014.The vertical turbulent heat fl ux constantly increased in the Atlantic sector year by year,while it decreased in the Pacific sector post 2010.The estimated heat flux variability induced by enhanced turbulent mixing is expected to continue to diminish sea ice in the near future.
基金supported by the National Natural Science Foundation of China (60972152)Northwestern Polytechnical University Foun dations for Fundamental Research (JC201027 JC20100223)
文摘The problem of distributed detection fusion using multiple sensors for remote underwater target detection is studied. Considering that multiple access channel （MAC） schemes are able to offer high efficiency in bandwidth usage and consume less energy than the parallel access channel （PAC）, the MAC scheme is introduced into the underwater target detection field. The model of underwater distributed detection fusion based on MAC schemes is established. A new method for detection fusion of MAC based on deflection coefficient maximization （DCM） and Neyman-Pearson （NP） rule is proposed. Under the power constraint of local sensors, this paper uses the DCM theory to derive the optimal weight coefficients and offsets. The closed-form expressions of detection probability and false alarm probability for fusion systems are obtained. The optimal detection performance of fusion systems is analyzed and deeply researched. Both the theory analysis and simulation experiments indicate that the proposed method could improve the detection performance and decrease the error probability effectively under power constraints of local sensors and low signal to noise ratio.
基金Supported by the National Key Research and Development Program of China and National Natural Science Foundation of China(Nos.2019YFE0105700,2016YFC1402705,2017YFA0604102,92058202,91858103,42176244,2016YFC1401404)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA22050202,XDB42000000)+1 种基金the CAS Key Research Program of Frontier Sciences and Key Deployment Project of Centre for Ocean Mega-Research of Science(Nos.QYZDB-SSW-DQC024,COMS2020Q07)the project jointly funded by the CAS and CSIRO(No.133244KYSB20190031)。
文摘A series of non-hydrostatic,non-linear numerical simulations were carried out to investigate the generation and evolution of internal solitary waves(ISWs)through the interaction of a barotropic tidal current with an ice keel in the Arctic Ocean.During the interaction process,the internal surge was generated at first,and then the wave gradually steepened due to non-linearity during its propagation away from the ice keel.The internal surge eventually disintegrated into multi-modal and rank-ordered ISW packets with the largest having an amplitude of O(10)m.Sensitivity experiments demonstrated that the ISWs’amplitudes and energy were proportional to the varying ice keel depths and barotropic tidal fl ow amplitudes,but were insensitive to the changing ice keel widths.Typical ISWs can enhance the turbulent dissipation rate of O(10^(-6))W/kg along their propagation path.Further,heat entrainment induced by the wave-ice interaction can reach O(10)MJ/m per tidal cycle.This study reveals a particular ISW generation mechanism and process in the polar ice environment,which could be important in impacting the energy transfer and heat balance in the Arctic Ocean.
基金supported by the Fujian Provincial Government Project (Title: Research on whole process evaluation of dynamic stability and control strategy in condition of grid connection of ultra-high voltage and large scale penetration of nuclear power.No.2015H0023)the State Grid Science & Technology Project (Title: Research on the improvement on stability of primary frequency of generator in account of the tolerance of equipment.No.52130417002P)the Key project of State Grid Fujian Electric Power Company,Ltd (research on key technologies of primary frequency power oscillation mechanism analysis and inhibition measures in large-scale unit in Fujian power grid.No.52130417000J)
文摘This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated in isolated state are identified. Second, different schemes are proposed for generator mode switching from on-grid to off-grid state through comparison and mechanism analysis. Third, the time domain model and frequency domain model of the isolated generator governor are constructed to respectively estimate the primary frequency performance and small signal stability. Parameter sets that satisfy the primary frequency performance and small signal stability are acquired as optimal values of governor control parameters. Finally, the measurement-based parameters of the governor are identified and validated using simulations to demonstrate the feasibility and effectiveness of the method.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA22050202,XDB42000000)the National Natural Science Foundation of China(Nos.92058202,91858103)+3 种基金the National Key Research and Development Program of China(Nos.2017YFA0604102,2016YFC1401404)the CAS Key Research Program of Frontier Sciences(No.QYZDB-SSW-DQC024)the Key Deployment Project of Centre for Ocean Mega-Research of Science,Chinese Academy of Sciences(No.COMS2020Q07)jointly supported by the Chinese Academy of Sciences(CAS)and Commonwealth Scientific and Industrial Research Organisation(CSIRO)(No.133244KYSB20190031)。
文摘The generation and propagation characteristics of near-inertial waves(NIWs)generated spontaneously from a quasi-geostrophic anticyclonic mesoscale eddy in a rotating and stratifi ed fl uid were investigated by three-dimensional numerical modeling.NIWs are generated over a long time interval as a forced response to balanced baroclinic mesoscale eddies.For such eddies,NIW generation from balanced flow is an inevitable result as the evolution of eddies.Moreover,the baroclinicity of mesoscale eddies is an essential condition for this NIW generation mechanism.The spontaneously generated NIWs radiate horizontally toward the eddy center and propagate upward in vertical direction.The forcing of the NIWs moves downward along the eddy axis from the location of maximum temperature anomaly of the mesoscale eddy.The moving speed of the forcing is independent on the balanced mesoscale eddies but is determined by the ratio of buoyancy to inertial frequency.When the forcing reaches the bottom of the mesoscale eddy,the spontaneous NIW generation process terminates.NIW intensity in this spontaneous generation process is strengthened with the increase of the Rossby and Froude numbers.Further research to gain a solid understanding of the role of the Rossby and Froude numbers is necessary for the parameterization of spontaneous NIW generation from quasi-geostrophic mesoscale eddies in general circulation model.
基金The National Key Research and Development Project(No.2022YFE0124100)Ordos Key Research and Development Project(No.2022EEDSKJZDZX003)+3 种基金National Natural Science Foundation of China(Nos.21872060,21902054,21761132014,and 22072049)the Open Research Fund(No.2022JYBKF01)of Key Laboratory of Material Chemistry for Energy Conversion and Storage(HUST),Ministry of Education,are acknowledged for the financial supportProgram for HUST Academic Frontier Youth Team(No.2019QYTD06)is also acknowledgedsupported by The Innovation and Talent Recruitment Base of New Energy Chemistry and Device。
文摘Acid-catalyzed tandem reactions were established by employing a novel class of 2-arylglycerol derivative,5-aryl-1,3-dioxan-5-ol,as versatile 1,3-biselectrophile.In the reactions,5-aryl-1,3-dioxan-5-ol works like atropaldehydes or 2-aryl malondialdehydes,and can react with 2-naphthols andβ-keto amides,allowing the synthesis of 4H-chromenes and 5-aryl-2-pyridinones.High yields,good functional group tolerance,broad substrate scope and simple reaction operation make this protocol attractive.
基金This work was supported partly by the National Natural Science Foundation of China(81541153 and 81772404)The Guangdong Science and Technology Department(2016A050503046,2015A050502048,2016B030309002 and 2019B090905011)+1 种基金The Fund of Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)(ZJW-2019-007)The Public Service Platform of South China Sea for R&D Marine Biomedicine Resources(GDMUK201808).
文摘Cancer cells are abnormal cells that can reproduce and regenerate rapidly.They are characterized by unlimited proliferation,transformation and migration,and can destroy normal cells.To meet the needs for cell proliferation and migration,tumor cells acquire molecular materials and energy through unusual metabolic pathways as their metabolism is more vigorous than that of normal cells.Multiple carcinogenic signaling pathways eventually converge to regulate three major metabolic pathways in tumor cells,including glucose,lipid,and amino acid metabolism.The distinct metabolic signatures of cancer cells reflect that metabolic changes are indispensable for the genesis and development of tumor cells.In this review,we report the unique metabolic alterations in tumor cells which occur through various signaling axes,and present various modalities available for cancer diagnosis and clinical therapy.We further provide suggestions for the development of anti-tumor therapeutic drugs.
基金Supported by the Major State Basic Research and Development Program of People's Republic of China(No.2009CB522902)National Key Technology R&D Program(No.2006BAI12B04-2)+2 种基金National Natural Science Foundation of China(No.81160453)National Natural Science Foundation of China(No.81202854)Jiangxi Key R&D Project
文摘OBJECTIVE:To compare the curative effects of heat-sensitive moxibustion with conventional drugs on chronic persistent asthma and seek a valuable therapy to replaceWestern Medicine.METHODS:The participants in this multi-center,randomized,and controlled study were randomly divided into two groups:group A(n=144),treated with heat-sensitive moxibustion(50 sessions)and group B(n=144),treated with Seretide(salmeterol50μg/fluticasone 250μg,twice a day).The scores of asthma control test(ACT),forced expiratory volume in 1 second(FEV1),peak expiratory flow(PEF),and attack frequency were measured after 15,30,60,and 90 days of treatment.Patients followed up3 and 6 months after treatment.RESULTS:There was a significant difference(P=0.0002)in the ACT score and lung function between the two groups after 3 months of treatment and(P=0.000 03)during the follow-up visits.In addition,heat-sensitive moxibustion reduced attack frequency in the period from inclusion to the6-month follow-up visit.CONCLUSION:This study shows that heat-sensitive moxibustion may have a comparable curative effect toSeretide(salmeterol/fluticasone)on asthma.
基金the National Natural Science Foundation of China(22071211)the Science and Technology Planning Project of Hunan Province(2019RS2039)+2 种基金Hunan Provincial Natural Science Foundation of China(2020JJ3032)the Hunan Provincial Innovative Foundation of Postgraduate(CX20190482,XDCX2019B091)the Collaborative Innovation Center of New Chemical Technologies for Environmental Benignity and Efficient Resource Utilization is gratefully acknowledged.
文摘A facile copper-based catalytic system has been developed to enable efficient cyclization of methylketoximes and alkynals.This protocol provides a viable entry to synthetically and pharmaceutically useful 2-acylpyrroles with a broad range of compatible functionalities.Mechanistically,a key acyl migration is probably involved that leads to the formation of N-acyl pyrroles or otherwise NH pyrroles by further hydrolysis.More importantly,the present reaction system also gives an opportunity to realize three-component pyrrole assembly by simple addition of carboxylic acid.
