Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduit...Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduits may be used.The ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve regeneration.We designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align them.Subsequently,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber lumen.The presence of aligned fibers on the inner surface can promote the extension of nerve cells along the fibers.The helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide stability.Our novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.展开更多
Abstract The dopamine transporter （DAT） is involved in the regulation of extracellular dopamine levels. A 40-bp variable-number tandem repeat （VNTR） polymorphism in the 3-untranslated region （3UTR） of the DAT ha...Abstract The dopamine transporter （DAT） is involved in the regulation of extracellular dopamine levels. A 40-bp variable-number tandem repeat （VNTR） polymorphism in the 3-untranslated region （3UTR） of the DAT has been reported to be associated with various phenotypes that are involved in the aberrant regulation of dopaminergic neu- rotransmission. In the present study, we found that miR- 137 and miR-491 caused a marked reduction of DAT expression, thereby influencing neuronal dopamine trans- port. Moreover, the regulation of miR-137 and miR-491 on this transport disappeared after the DAT was silenced. The miR-491 seed region that is located on the VNTR sequence in the 3＇UTR of the DAT and the regulatory effect of miR- 491 on the DAT depended on the VNTR copy-number. These data indicate that miR-137 and miR-491 regulate DAT expression and dopamine transport at the post- transcriptional level, suggesting that microRNA may be targeted for the treatment of diseases associated with DAT dysfunction.展开更多
The Beijing 325 m meteorological tower stands as a pivotal research platform for exploring atmospheric boundary layer physics and atmospheric chemistry.With a legacy spanning 45 years,the tower has played a crucial ro...The Beijing 325 m meteorological tower stands as a pivotal research platform for exploring atmospheric boundary layer physics and atmospheric chemistry.With a legacy spanning 45 years,the tower has played a crucial role in unraveling the complexities of urban air pollution,atmospheric processes,and climate change in Beijing,China.This review paper provides a comprehensive overview of the measurements on the tower over the past two decades.Through long-term comprehensive observations,researchers have elucidated the intricate relationships between anthropogenic emissions,meteorological dynamics,and atmospheric composition,shedding light on the drivers of air pollution and its impacts on public health.The vertical measurements on the tower also enable detailed investigations into boundary layer dynamics,turbulent mixing,and pollutant dispersion,providing invaluable data for validating chemical transport models.Key findings from the tower’s research include the identification of positive feedback mechanisms between aerosols and the boundary layer,the characterization of pollutant sources and transport pathways,the determination of fluxes of gaseous and particulate species,and the assessment of the effectiveness of pollution control measures.Additionally,isotopic measurements have provided new insights into the sources and formation processes of particulate matter and reactive nitrogen species.Finally,the paper outlines future directions for tower-based research,emphasizing the need for long-term comprehensive measurements,the development of innovative tower platforms,and integration of emerging technologies.展开更多
Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.H...Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.However,these antibiotics often target the growth factors of the pathogenic bacteria,leading to the accumulation and emergence of drug-resistant strains,which exacerbates antibiotic resistance.Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria.Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance.TypeⅢsecretion system(T3SS)serves as a crucial virulence determinant in Gram-negative pathogens,and its non-essentials for pathogen growth renders it an ideal target.Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens.Therefore,targeting T3SS in pathogenic bacteria,while preserving their growth,has emerged as a novel avenue for the development of antimicrobial drugs.In recent years,a multitude of small molecular inhibitors targeting T3SS have been identified.This article offers a comprehensive review of T3SS inhibitors in plant pathogens,while also presenting the latest research advancements in this research direction.展开更多
Intracellular bacteria(ICB),cloaked by the protective barriers of host cells,pose a formidable challenge to selective and efficient eradication.The employment of activatable photosensitizers based antibacterial photod...Intracellular bacteria(ICB),cloaked by the protective barriers of host cells,pose a formidable challenge to selective and efficient eradication.The employment of activatable photosensitizers based antibacterial photodynamic therapy(a PDT)holds significant potential for selective imaging and photo-inactivation of ICB while minimizing side effects on normal cells.Drawing inspiration from the elevated hypochlorous acid(HClO)levels in ICB infected phagocytes,herein we firstly designed and synthesized a series of HCl Oresponsive dinuclear Ru(Ⅱ)complexes(Ru1-Ru3)to achieve such a goal.Initially,the luminescence,^(1)O_(2)generation and a PDT activity of these Ru(Ⅱ)complexes were suppressed due to the quenching effect of the azo group,but were recovered after reaction with HCl O in solutions or within ICB infected phagocytes.The detailed results revealed that Ru1 and Ru3 could not only selectively visualize ICB,but also demonstrated remarkable a PDT activity against ICB,surpassing vancomycin both in vitro and in vivo.展开更多
With the aim of maximizing nitrogen use efficiency(NUE)of wheat in the North China Plain by optimizing irrigation and nitrogen application,a field experiment with a split-plot design was conducted.The main plots were ...With the aim of maximizing nitrogen use efficiency(NUE)of wheat in the North China Plain by optimizing irrigation and nitrogen application,a field experiment with a split-plot design was conducted.The main plots were subjected to three irrigation levels:bringing soil water content in the 0–40 cm profile to 65%(I1),75%(I2)and 85%(I3)of field water capacity.The subplots were subjected to three nitrogen application rates:150(N150),210(N210)and 270(N270)kg N ha−1.Compared with the N270,N210 treatment enhanced grain yield,NUE,and net income by 4.5%,6.2%,and 5.8%,respectively(two-year averages).Additionally,it reduced soil nitrate reductase activity,the abundance of denitrification-related bacteria,and loss rate of fertilizer nitrogen by 12.9%,53.3%,and 16.3%,respectively.Compared with the N150,N210 treatment increased grain yield,grain nitrogen accumulation,and net income by 15.9%,14.2%,and 26.3%.Relative to I1 and I3,I2 treatment increased root length density in the 20–60 cm soil layer,uptake rate of fertilizer nitrogen,grain yield,and net income.Overall,the combination of irrigation to 75%of field capacity with nitrogen application at 210 kg N ha^(−1)increased wheat’s capacity for nitrogen uptake and remobilization and thereby grain nitrogen accumulation,and increased NUE by reducing nitrogen loss rate.展开更多
Dry reforming of methane(DRM)converts CH4 and CO_(2) to syngas.Photothermal DRM,which integrates temperature and light,is a sustainable method for storing solar energy in molecules.However,challenges such as limited l...Dry reforming of methane(DRM)converts CH4 and CO_(2) to syngas.Photothermal DRM,which integrates temperature and light,is a sustainable method for storing solar energy in molecules.However,challenges such as limited light absorption,low photocarrier separation efficiency,Ni sintering,and carbon deposition hinder DRM stability.Herein,we regulated Ni contents in(Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalysts to enhance the optical characteristics while addressing Ni sintering and carbon deposition issues.The(3Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalyst had insufficient Ni content,while the(9Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalyst showed excessive carbon deposition,leading to lower stability compared to the(6Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalyst,which achieved CH4 and CO_(2) rates to 231.0 μmol gcat^(-1)s^(-1) and 294.3 μmol gcat^(-1)s^(-1) ,respectively,at 973 K,with only 0.2 wt.%carbon deposition and no Ni sintering.This work adjusted Ni contents in(Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalysts to enhance DRM performance,which has implications for improving other reactions.展开更多
Tight oil reservoirs face significant challenges,including rapid production decline,low recovery rates,and a lack of effective energy replenishment methods.In this study,a novel development model is proposed,based on ...Tight oil reservoirs face significant challenges,including rapid production decline,low recovery rates,and a lack of effective energy replenishment methods.In this study,a novel development model is proposed,based on inter-fracture injection following volumetric fracturing and relying on a high-temperature and high-pressure large-scale physical simulation system.Additionally,the CMG(Computer Modelling Group Ltd.,Calgary City,Canada)software is also used to elucidate the impact of various single factors on the production of horizontal wells while filtering out the interference of others.The effects of fracture spacing,fracture half-length,and the injection-production ratio are studied.Results indicate that under rejection pressures of 6.89,3.45,and 1.88 MPa,the times to establish stable flow are 50,193,and 395 min,respectively.Higher injection pressures lead to an increased oil recovery efficiency,with the highest observed efficiency at 16.93%.This indicates that,compared with conventional medium and high permeability reservoirs,tight oil reservoirs exhibit similar pore throats and larger capillary forces when oil and water flow in both phases.Higher pressures reduce capillary forces,displacing more oil droplets,thus enhancing oil recovery efficiency.Moreover,under inter-fracture displacement conditions,the pressure gradient at both the injection and production ends remain consistent,with minimal pressure loss near the wellbore.This feature ensures that the crude oil in the middle of the reservoir also possesses displacement energy,thereby enhancing overall crude oil displacement efficiency.展开更多
Temperature is a key meteorological factor that affects tropospheric ozone(O_(3)),with both humid-heat(sauna days)and dry-heat(roast days)conditions leading to O_(3) exceedances.However,the mechanisms influencing O_(3...Temperature is a key meteorological factor that affects tropospheric ozone(O_(3)),with both humid-heat(sauna days)and dry-heat(roast days)conditions leading to O_(3) exceedances.However,the mechanisms influencing O_(3) formation and degradation under these two weather conditions remain unclear.Therefore,experiments were conducted in Beijing from 2019 to 2021 to observe O_(3),its precursors,and related meteorological elements.A total of 18 days with O_(3) exceedances were selected,including 10 sauna days and 8 roast days.The results of this study revealed that on roast days,the sensible heat flux was 143.5 W/m^(2) greater and the wind speed gradient was 0.018 s^(-1) greater than those on sauna days,indicating more intense thermal and dynamic turbulence.The strong turbulence enhanced the vertical cycle of nitrogen dioxide(NO_(2))and O_(3),resulting in a 58.2μg/(m^(2)·h)increase in NO_(2) upward transport rate and a 1034.4μg/(m^(2)·h)increase in O_(3) downward transport rate on roast days than sauna days.Subsequently,a box model analysis was used to examine O_(3) formation under the two types of weather conditions,revealing that the NO_(2)-O_(3) vertical cycling speed dominated the O_(3) sensitivity.The O_(3) sensitivity was synergistically controlled by nitrogen oxides(NO_(x))and volatile organic compounds on sauna days,while it tended to be NO_(x)-limited on roast days.The aim of this study was to provide a scientific theoretical basis for the control of O_(3) under different types of high temperature weather conditions.展开更多
The 7075 aluminum alloy was subjected to power-modulated laser welding using a full-domain power modulation(FDPM)laser oscillating welding system.Three different power modes were utilized:constant power(CP),gradient p...The 7075 aluminum alloy was subjected to power-modulated laser welding using a full-domain power modulation(FDPM)laser oscillating welding system.Three different power modes were utilized:constant power(CP),gradient power(GP),and alternating power(AP)modes.The impact of different power modes on joint crack sensitivity,microstructure,and residual stress was assessed.The results demonstrate that joint welded with the AP mode exhibits the lowest sensitivity to solidification cracking(with mean crack sensitivity of 18.3%),and the smallest average grain size in the fusion zone of the weld seam(80μm).Additionally,it shows the highest microhardness(HV 113)and the narrowest softening region(3.5 cm).Furthermore,the joint displays the lowest residual stress and cooling rate,which is the reason for its minimal crack sensitivity.展开更多
Volumetric additive manufacturing(VAM) transforms traditional 2D light pattern projection into spatial light field energy superposition,maximizing the utilization of radiated light and allowing for ultra-fast,support-...Volumetric additive manufacturing(VAM) transforms traditional 2D light pattern projection into spatial light field energy superposition,maximizing the utilization of radiated light and allowing for ultra-fast,support-free printing,which has specific applications in fields such as life sciences and optics.However,traditional VAM processes require numerous projections and extensive computational preparation,limiting practical applications due to low projection efficiency and prolonged calculation times.In this study,we developed sparse-view irradiation processing VAM(SVIP-VAM),employing an optimized odd-even(OE) irradiation strategy inspired by sparse-view computed tomography.Theoretically,we demonstrated structural contour reconstruction feasibility with as few as 8 projections.Using this sparse-view approach,we achieved high-quality fabrication with only 15 projections,enhancing each projection efficiency by over 60 times and reducing projection set computational time by nearly 10-fold.Ultimately,this efficient sparse-view method significantly expands VAM applications into fields requiring rapid manufacturing,such as tissue engineering,medical implants,and aerospace manufacturing.展开更多
Traumatic brain injury(TBI)remains a prominent global cause of mortality and disability,accounting for an estimated 69 million new cases annually[1].Both civilian and military populations face substantial health chall...Traumatic brain injury(TBI)remains a prominent global cause of mortality and disability,accounting for an estimated 69 million new cases annually[1].Both civilian and military populations face substantial health challenges due to TBI,particularly in military settings,where combat-related injuries introduce unique considerations for prevalence and management[2].Despite notable advancements in acute care,our comprehension of the complex pathophysiological mechanisms underlying the long-term eff ects of TBI remains inadequate[3].Although the initial mechanical impact triggers the cascade of injury,it is often the subsequent neuroinfl ammatory processes that propel progressive neuronal damage and lead to long-term neurological impairments[4,5].展开更多
基金supported by the National Natural Science Foundation of China,No.82202718the Natural Science Foundation of Beijing,No.L212050the China Postdoctoral Science Foundation,Nos.2019M664007,2021T140793(all to ZL)。
文摘Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduits may be used.The ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve regeneration.We designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align them.Subsequently,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber lumen.The presence of aligned fibers on the inner surface can promote the extension of nerve cells along the fibers.The helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide stability.Our novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.
基金supported by grants from the National Postdoctoral Science Foundation,China(2014M552219)the Natural Science Foundation of Guangdong Province,China(2015 A030313889,2015A030401013,2014A030313709,and 2014A030 313710)+1 种基金the Science and Technology Planning Project of Shenzhen Municipality,China(ZDSYS201504301045406,JCYJ20150403110 829621,JCYJ20150403091443301,JCYJ20140415162542975,JCYJ 20140415162338855,JCYJ20140828163634004,and JCYJ201206 16144352139)the Health and Family Planning Commission Project of Shenzhen Municipality,China(201401026)
文摘Abstract The dopamine transporter （DAT） is involved in the regulation of extracellular dopamine levels. A 40-bp variable-number tandem repeat （VNTR） polymorphism in the 3-untranslated region （3UTR） of the DAT has been reported to be associated with various phenotypes that are involved in the aberrant regulation of dopaminergic neu- rotransmission. In the present study, we found that miR- 137 and miR-491 caused a marked reduction of DAT expression, thereby influencing neuronal dopamine trans- port. Moreover, the regulation of miR-137 and miR-491 on this transport disappeared after the DAT was silenced. The miR-491 seed region that is located on the VNTR sequence in the 3＇UTR of the DAT and the regulatory effect of miR- 491 on the DAT depended on the VNTR copy-number. These data indicate that miR-137 and miR-491 regulate DAT expression and dopamine transport at the post- transcriptional level, suggesting that microRNA may be targeted for the treatment of diseases associated with DAT dysfunction.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0760200)the National Natural Science Foundation of China(Grant Nos.42330605 and 42377101).
文摘The Beijing 325 m meteorological tower stands as a pivotal research platform for exploring atmospheric boundary layer physics and atmospheric chemistry.With a legacy spanning 45 years,the tower has played a crucial role in unraveling the complexities of urban air pollution,atmospheric processes,and climate change in Beijing,China.This review paper provides a comprehensive overview of the measurements on the tower over the past two decades.Through long-term comprehensive observations,researchers have elucidated the intricate relationships between anthropogenic emissions,meteorological dynamics,and atmospheric composition,shedding light on the drivers of air pollution and its impacts on public health.The vertical measurements on the tower also enable detailed investigations into boundary layer dynamics,turbulent mixing,and pollutant dispersion,providing invaluable data for validating chemical transport models.Key findings from the tower’s research include the identification of positive feedback mechanisms between aerosols and the boundary layer,the characterization of pollutant sources and transport pathways,the determination of fluxes of gaseous and particulate species,and the assessment of the effectiveness of pollution control measures.Additionally,isotopic measurements have provided new insights into the sources and formation processes of particulate matter and reactive nitrogen species.Finally,the paper outlines future directions for tower-based research,emphasizing the need for long-term comprehensive measurements,the development of innovative tower platforms,and integration of emerging technologies.
基金the financial support from the National Key Research and Development Program of China(No.2023YFD1701100)the National Natural Science Foundation of China(No.32072450)+2 种基金the National Science Fund for Distinguished Young Scholars of Guangdong Province(No.2021B1515020107)the Opening Foundation of Hubei Key Laboratory of Novel Reactor and Green Chemical Technology(No.NRG202306)the Opening Foundation of Guangdong Province Key Laboratory of Microbial Signals and Disease Control(No.MSDC2023-19)。
文摘Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.However,these antibiotics often target the growth factors of the pathogenic bacteria,leading to the accumulation and emergence of drug-resistant strains,which exacerbates antibiotic resistance.Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria.Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance.TypeⅢsecretion system(T3SS)serves as a crucial virulence determinant in Gram-negative pathogens,and its non-essentials for pathogen growth renders it an ideal target.Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens.Therefore,targeting T3SS in pathogenic bacteria,while preserving their growth,has emerged as a novel avenue for the development of antimicrobial drugs.In recent years,a multitude of small molecular inhibitors targeting T3SS have been identified.This article offers a comprehensive review of T3SS inhibitors in plant pathogens,while also presenting the latest research advancements in this research direction.
基金supported by National Natural Science Foundation of China(No.22371289)。
文摘Intracellular bacteria(ICB),cloaked by the protective barriers of host cells,pose a formidable challenge to selective and efficient eradication.The employment of activatable photosensitizers based antibacterial photodynamic therapy(a PDT)holds significant potential for selective imaging and photo-inactivation of ICB while minimizing side effects on normal cells.Drawing inspiration from the elevated hypochlorous acid(HClO)levels in ICB infected phagocytes,herein we firstly designed and synthesized a series of HCl Oresponsive dinuclear Ru(Ⅱ)complexes(Ru1-Ru3)to achieve such a goal.Initially,the luminescence,^(1)O_(2)generation and a PDT activity of these Ru(Ⅱ)complexes were suppressed due to the quenching effect of the azo group,but were recovered after reaction with HCl O in solutions or within ICB infected phagocytes.The detailed results revealed that Ru1 and Ru3 could not only selectively visualize ICB,but also demonstrated remarkable a PDT activity against ICB,surpassing vancomycin both in vitro and in vivo.
基金supported by the National Natural Science Foundation of China(32172114)China Agriculture Research System of MOF and MARA(CARS-03)Taishan scholar Project Special Funds(202211094).
文摘With the aim of maximizing nitrogen use efficiency(NUE)of wheat in the North China Plain by optimizing irrigation and nitrogen application,a field experiment with a split-plot design was conducted.The main plots were subjected to three irrigation levels:bringing soil water content in the 0–40 cm profile to 65%(I1),75%(I2)and 85%(I3)of field water capacity.The subplots were subjected to three nitrogen application rates:150(N150),210(N210)and 270(N270)kg N ha−1.Compared with the N270,N210 treatment enhanced grain yield,NUE,and net income by 4.5%,6.2%,and 5.8%,respectively(two-year averages).Additionally,it reduced soil nitrate reductase activity,the abundance of denitrification-related bacteria,and loss rate of fertilizer nitrogen by 12.9%,53.3%,and 16.3%,respectively.Compared with the N150,N210 treatment increased grain yield,grain nitrogen accumulation,and net income by 15.9%,14.2%,and 26.3%.Relative to I1 and I3,I2 treatment increased root length density in the 20–60 cm soil layer,uptake rate of fertilizer nitrogen,grain yield,and net income.Overall,the combination of irrigation to 75%of field capacity with nitrogen application at 210 kg N ha^(−1)increased wheat’s capacity for nitrogen uptake and remobilization and thereby grain nitrogen accumulation,and increased NUE by reducing nitrogen loss rate.
基金support from the National Natural Science Foundation of China(22078134)State Key Laboratory of Clean and Efficient Coal Utilization of Taiyuan University of Technology(SKL2022006)Natural Science Foundation of Chongqing(CSTB2023NSCQ-MSX0162)are greatly appreciated for the work.
文摘Dry reforming of methane(DRM)converts CH4 and CO_(2) to syngas.Photothermal DRM,which integrates temperature and light,is a sustainable method for storing solar energy in molecules.However,challenges such as limited light absorption,low photocarrier separation efficiency,Ni sintering,and carbon deposition hinder DRM stability.Herein,we regulated Ni contents in(Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalysts to enhance the optical characteristics while addressing Ni sintering and carbon deposition issues.The(3Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalyst had insufficient Ni content,while the(9Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalyst showed excessive carbon deposition,leading to lower stability compared to the(6Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalyst,which achieved CH4 and CO_(2) rates to 231.0 μmol gcat^(-1)s^(-1) and 294.3 μmol gcat^(-1)s^(-1) ,respectively,at 973 K,with only 0.2 wt.%carbon deposition and no Ni sintering.This work adjusted Ni contents in(Ni/Ce_(0.8)Zr_(0.2)O_(2))@SiO_(2) catalysts to enhance DRM performance,which has implications for improving other reactions.
基金supported by the Study on the Seepage Law of Typical Low-Grade Oil Reservoirs,New Methods for Enhancing Oil Recovery(2021DJ1102)the National Science and Technology Major Special Support Program(Grant No.2017ZX05064)the CNPC Innovation Foundation(Grant No.2022DQ02-0604).
文摘Tight oil reservoirs face significant challenges,including rapid production decline,low recovery rates,and a lack of effective energy replenishment methods.In this study,a novel development model is proposed,based on inter-fracture injection following volumetric fracturing and relying on a high-temperature and high-pressure large-scale physical simulation system.Additionally,the CMG(Computer Modelling Group Ltd.,Calgary City,Canada)software is also used to elucidate the impact of various single factors on the production of horizontal wells while filtering out the interference of others.The effects of fracture spacing,fracture half-length,and the injection-production ratio are studied.Results indicate that under rejection pressures of 6.89,3.45,and 1.88 MPa,the times to establish stable flow are 50,193,and 395 min,respectively.Higher injection pressures lead to an increased oil recovery efficiency,with the highest observed efficiency at 16.93%.This indicates that,compared with conventional medium and high permeability reservoirs,tight oil reservoirs exhibit similar pore throats and larger capillary forces when oil and water flow in both phases.Higher pressures reduce capillary forces,displacing more oil droplets,thus enhancing oil recovery efficiency.Moreover,under inter-fracture displacement conditions,the pressure gradient at both the injection and production ends remain consistent,with minimal pressure loss near the wellbore.This feature ensures that the crude oil in the middle of the reservoir also possesses displacement energy,thereby enhancing overall crude oil displacement efficiency.
基金supported by the National Natural Science Foundation of China(No.42177081)the National Key R&D Program of China(No.2023YFC3706103)+1 种基金Beijing Municipal Natural Science Foundation(No.8222075)the Youth Cross Team Scientific Research Project of the Chinese Academy of Sciences(No.JCTD-2021–10).
文摘Temperature is a key meteorological factor that affects tropospheric ozone(O_(3)),with both humid-heat(sauna days)and dry-heat(roast days)conditions leading to O_(3) exceedances.However,the mechanisms influencing O_(3) formation and degradation under these two weather conditions remain unclear.Therefore,experiments were conducted in Beijing from 2019 to 2021 to observe O_(3),its precursors,and related meteorological elements.A total of 18 days with O_(3) exceedances were selected,including 10 sauna days and 8 roast days.The results of this study revealed that on roast days,the sensible heat flux was 143.5 W/m^(2) greater and the wind speed gradient was 0.018 s^(-1) greater than those on sauna days,indicating more intense thermal and dynamic turbulence.The strong turbulence enhanced the vertical cycle of nitrogen dioxide(NO_(2))and O_(3),resulting in a 58.2μg/(m^(2)·h)increase in NO_(2) upward transport rate and a 1034.4μg/(m^(2)·h)increase in O_(3) downward transport rate on roast days than sauna days.Subsequently,a box model analysis was used to examine O_(3) formation under the two types of weather conditions,revealing that the NO_(2)-O_(3) vertical cycling speed dominated the O_(3) sensitivity.The O_(3) sensitivity was synergistically controlled by nitrogen oxides(NO_(x))and volatile organic compounds on sauna days,while it tended to be NO_(x)-limited on roast days.The aim of this study was to provide a scientific theoretical basis for the control of O_(3) under different types of high temperature weather conditions.
基金supported by the National Natural Science Foundation of China(No.52075235)the Major Science and Technology Project of Gansu Province,China(No.22ZD6GA008)+2 种基金the Key Research and Development Program of Gansu Province,China(No.20YF3WA017)the Natural Science Foundation of Gansu Province,China(No.21JR7RA233)the Scientific and Technological Projects of Jiayuguan,China(No.22-16)。
文摘The 7075 aluminum alloy was subjected to power-modulated laser welding using a full-domain power modulation(FDPM)laser oscillating welding system.Three different power modes were utilized:constant power(CP),gradient power(GP),and alternating power(AP)modes.The impact of different power modes on joint crack sensitivity,microstructure,and residual stress was assessed.The results demonstrate that joint welded with the AP mode exhibits the lowest sensitivity to solidification cracking(with mean crack sensitivity of 18.3%),and the smallest average grain size in the fusion zone of the weld seam(80μm).Additionally,it shows the highest microhardness(HV 113)and the narrowest softening region(3.5 cm).Furthermore,the joint displays the lowest residual stress and cooling rate,which is the reason for its minimal crack sensitivity.
基金supported financially by the Beijing Municipal Natural Science Foundation (L232109)National Natural Science Foundation of China (22073003)Fundamental Research Funds for the Central Universities (YWF-22-K-101)。
文摘Volumetric additive manufacturing(VAM) transforms traditional 2D light pattern projection into spatial light field energy superposition,maximizing the utilization of radiated light and allowing for ultra-fast,support-free printing,which has specific applications in fields such as life sciences and optics.However,traditional VAM processes require numerous projections and extensive computational preparation,limiting practical applications due to low projection efficiency and prolonged calculation times.In this study,we developed sparse-view irradiation processing VAM(SVIP-VAM),employing an optimized odd-even(OE) irradiation strategy inspired by sparse-view computed tomography.Theoretically,we demonstrated structural contour reconstruction feasibility with as few as 8 projections.Using this sparse-view approach,we achieved high-quality fabrication with only 15 projections,enhancing each projection efficiency by over 60 times and reducing projection set computational time by nearly 10-fold.Ultimately,this efficient sparse-view method significantly expands VAM applications into fields requiring rapid manufacturing,such as tissue engineering,medical implants,and aerospace manufacturing.
基金supported by the National Natural Science Foundation of China(82102645)the Guangdong Basic and Applied Basic Research Foundation(2021A1515011042)the China Postdoctoral Science Foundation(2019M662995).
文摘Traumatic brain injury(TBI)remains a prominent global cause of mortality and disability,accounting for an estimated 69 million new cases annually[1].Both civilian and military populations face substantial health challenges due to TBI,particularly in military settings,where combat-related injuries introduce unique considerations for prevalence and management[2].Despite notable advancements in acute care,our comprehension of the complex pathophysiological mechanisms underlying the long-term eff ects of TBI remains inadequate[3].Although the initial mechanical impact triggers the cascade of injury,it is often the subsequent neuroinfl ammatory processes that propel progressive neuronal damage and lead to long-term neurological impairments[4,5].
