This study examines the hemodynamics of non-Newtonian blood flow in stenosed arteries,focusing on the roles of stenosis severity,guidewire presence,and various non-Newtonian constitutive models.Computational simulatio...This study examines the hemodynamics of non-Newtonian blood flow in stenosed arteries,focusing on the roles of stenosis severity,guidewire presence,and various non-Newtonian constitutive models.Computational simulations using the generalized power-law,Casson,and Carreau-Yasuda models are conducted for stenosis severities of 50%,70%,80%,and 90%.Results indicate that stenosis severity exerts the greatest influence on pressure and wall shear stress(WSS),with increasing severity leading to higher pressure drops and WSS maxima.Guidewire presence reduces recirculation zone lengths by nearly 60%across different severities and raises the trans-stenotic pressure drop up to 120%.While the choice of constitutive model has minimal impact on hemodynamics within the stenotic region,it becomes crucial in healthy vessels,where non-Newtonian effects are more pronounced.In cases with a guidewire,pressure gradients in the healthy region show up to 18.8%differences between non-Newtonian models.These findings highlight the dominant roles of stenosis severity and guidewire presence in shaping hemodynamics within stenotic regions while emphasizing the need for precise constitutive modeling to capture flow characteristics in healthy vascular segments.展开更多
Illumina sequencing and quantitative PCR(qPCR)based on the 16 S ribosomal RNA(rRNA)gene were conducted to characterize the vertical distribution of bacterial and archaeal communities in the sediments of two sites from...Illumina sequencing and quantitative PCR(qPCR)based on the 16 S ribosomal RNA(rRNA)gene were conducted to characterize the vertical distribution of bacterial and archaeal communities in the sediments of two sites from the South Yellow Sea.Both bacterial and archaeal communities showed a clear stratified distribution with sediment depth.The microbial communities in the upper layers were distinct from those in the deeper layers;the relative abundances of sequences of Thaumarchaeota,Gammaproteobacteria,and Actinobacteria were higher in the upper than in the deeper sediments,whereas the sequences of Bathyarchaeia,Lokiarchaeota,Euryarchaeota,Chloroflexi,and Deltaproteobacteria were relatively more abundant in the deeper sediments.Sediment depth and total organic carbon(TOC)can significantly influence both the bacterial and archaeal communities.Furthermore,bacterial and archaeal groups potentially involved in nitrogen,sulfur,and methane metabolism were detected in both sites.In our study,both ammonia-oxidizing bacteria(Nitrospira)and ammonia-oxidizing archaea(Candidatus Nitrosopumilus)were responsible for ammonia oxidization.Additionally,sulfur-reducing bacteria SEEP-SRB1 forming consortia with anaerobic methane-oxidizing archaea ANME-2 a-2 b were capable of anaerobic methane oxidation(AOM)in the 3400-02 sediment samples.展开更多
Temperature and excitation dependent photoluminescence(PL) of InGaN epilayer grown on c-plane Ga N/sapphire template by molecular beam epitaxy(MBE) has been systematically investigated. The emission spectra of the sam...Temperature and excitation dependent photoluminescence(PL) of InGaN epilayer grown on c-plane Ga N/sapphire template by molecular beam epitaxy(MBE) has been systematically investigated. The emission spectra of the sample consisted of strong multiple peaks associated with one stimulated emission(SE) located at 430 nm and two spontaneous emissions(SPE) centered at about 450 nm and 480 nm, indicating the co-existence of shallow and deep localized states.The peak energy of SE exhibiting weak s-shaped variation with increasing temperature revealed the localization effect of excitons. Moreover, an abnormal increase of the SPE intensity with increasing temperature was also observed, which indicated that the carrier transfer between the shallow and deeper localized states exists. Temperature dependent time-resolved PL(TRPL) demonstrated the carrier transfer processes among the localized states. In addition, a slow thermalization of hot carriers was observed in InGaN film by using TRPL and transient differential reflectivity, which is attributed to the phonon bottleneck effect induced by indium aggregation.展开更多
Microorganisms in sediments are critical to marine ecosystems.The microbial communities in marine sediments of the Bohai Sea(BS)and Yellow Sea(YS),the eastern Chinese marginal seas,were uncovered in employing the meta...Microorganisms in sediments are critical to marine ecosystems.The microbial communities in marine sediments of the Bohai Sea(BS)and Yellow Sea(YS),the eastern Chinese marginal seas,were uncovered in employing the metagenomic approach.In addition,the taxonomic and functional compositions of microbes were compared among various sediment core depths.Results showing the compositions,diversities,and functions of the microbial communities showed no significant variations with sea areas,and significant seasonal variations was observed in station 3500-7 only on functions of the microbial communities.Moreover,the compositions,diversities,and functions of the microbial communities changed noticeably in different sediment depths in close correlation with physical and chemical properties of sediments.However,the large fraction of the variation in functional communities remained unexplained.From bioinformatic analysis of the metagenomic data,the carbon-metabolismrelated genes such as glycosyl transferase(GT),glycoside hydrolase(GH),and carbohydrate esterase(CE)genes were rich in the microbial community,especially in the top sediment depth.Additionally,in this N-polluted habitat,nitrification and anaerobic ammonia oxidation(anammox)were dominant in the top sediment depth,whereas dissimilatory nitrate reduction to ammonium(DNRA)and denitrification were dominant in the middle and bottom depth,respectively.Further identification of possible biogeochemical links suggested that Gammaproteobacteria,Alphaproteobacteria,Nitrospirae,Nitrospinae,Chloroflexi,and Methanomicrobia might promote effective circulation of carbon and nitrogen cycling.This study expanded our knowledge about the structure and functional potential of microbial communities associated with different sediment depth,and provided further comprehensive information on element cycles in marine environments.展开更多
为解决移动机器人在复杂地形场景的路径规划中易陷入局部最优和收敛速度慢等问题,提出了一种多策略集成的增强型人工大猩猩算法(enhanced artificial gorilla troops optimizer with integration of quadratic interpolation and elite ...为解决移动机器人在复杂地形场景的路径规划中易陷入局部最优和收敛速度慢等问题,提出了一种多策略集成的增强型人工大猩猩算法(enhanced artificial gorilla troops optimizer with integration of quadratic interpolation and elite individual genetic strategies,QGGTO)。融合二次插值策略和精英个体遗传策略,促进候选解之间的信息交流以加速收敛,并维持种群遗传多样性以避免局部最优。针对包含规则障碍物和不规则障碍物的复杂地形场景,构建了综合考虑行走距离、安全性和转向角度的成本函数,用于统一评估算法的路径规划性能。实验结果表明:QGGTO整体寻优性能优于GTO等7种竞争算法。在4种复杂障碍环境下,QGGTO能够辅助机器人规划出最接近全局最优的路径,验证了其在实际应用中的有效性。展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1000200 and 2021YFA1000201)National Natural Science Foundation of China(Grant Nos.12293001 and 12272009)+1 种基金Beijing Natural Science Foundation,China(Grant No.7232050)the Shenzhen Science and Technology Research and Development Grant,China(Grant No.KQTD20180411143400981).
文摘This study examines the hemodynamics of non-Newtonian blood flow in stenosed arteries,focusing on the roles of stenosis severity,guidewire presence,and various non-Newtonian constitutive models.Computational simulations using the generalized power-law,Casson,and Carreau-Yasuda models are conducted for stenosis severities of 50%,70%,80%,and 90%.Results indicate that stenosis severity exerts the greatest influence on pressure and wall shear stress(WSS),with increasing severity leading to higher pressure drops and WSS maxima.Guidewire presence reduces recirculation zone lengths by nearly 60%across different severities and raises the trans-stenotic pressure drop up to 120%.While the choice of constitutive model has minimal impact on hemodynamics within the stenotic region,it becomes crucial in healthy vessels,where non-Newtonian effects are more pronounced.In cases with a guidewire,pressure gradients in the healthy region show up to 18.8%differences between non-Newtonian models.These findings highlight the dominant roles of stenosis severity and guidewire presence in shaping hemodynamics within stenotic regions while emphasizing the need for precise constitutive modeling to capture flow characteristics in healthy vascular segments.
基金Supported by the National Key Research and Development Program of China(No.2017YFC1404402)the National Natural Science Foundation of China(Nos.41620104001,41806131)+1 种基金the Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ02)the China Postdoctoral Science Foundation(No.2018M632722)。
文摘Illumina sequencing and quantitative PCR(qPCR)based on the 16 S ribosomal RNA(rRNA)gene were conducted to characterize the vertical distribution of bacterial and archaeal communities in the sediments of two sites from the South Yellow Sea.Both bacterial and archaeal communities showed a clear stratified distribution with sediment depth.The microbial communities in the upper layers were distinct from those in the deeper layers;the relative abundances of sequences of Thaumarchaeota,Gammaproteobacteria,and Actinobacteria were higher in the upper than in the deeper sediments,whereas the sequences of Bathyarchaeia,Lokiarchaeota,Euryarchaeota,Chloroflexi,and Deltaproteobacteria were relatively more abundant in the deeper sediments.Sediment depth and total organic carbon(TOC)can significantly influence both the bacterial and archaeal communities.Furthermore,bacterial and archaeal groups potentially involved in nitrogen,sulfur,and methane metabolism were detected in both sites.In our study,both ammonia-oxidizing bacteria(Nitrospira)and ammonia-oxidizing archaea(Candidatus Nitrosopumilus)were responsible for ammonia oxidization.Additionally,sulfur-reducing bacteria SEEP-SRB1 forming consortia with anaerobic methane-oxidizing archaea ANME-2 a-2 b were capable of anaerobic methane oxidation(AOM)in the 3400-02 sediment samples.
基金Project supported by the National Key Research Program of China(Grant No.2016YFB0501604)the National Natural Science Foundation of China(Grant Nos.10874127 and 61227902)
文摘Temperature and excitation dependent photoluminescence(PL) of InGaN epilayer grown on c-plane Ga N/sapphire template by molecular beam epitaxy(MBE) has been systematically investigated. The emission spectra of the sample consisted of strong multiple peaks associated with one stimulated emission(SE) located at 430 nm and two spontaneous emissions(SPE) centered at about 450 nm and 480 nm, indicating the co-existence of shallow and deep localized states.The peak energy of SE exhibiting weak s-shaped variation with increasing temperature revealed the localization effect of excitons. Moreover, an abnormal increase of the SPE intensity with increasing temperature was also observed, which indicated that the carrier transfer between the shallow and deeper localized states exists. Temperature dependent time-resolved PL(TRPL) demonstrated the carrier transfer processes among the localized states. In addition, a slow thermalization of hot carriers was observed in InGaN film by using TRPL and transient differential reflectivity, which is attributed to the phonon bottleneck effect induced by indium aggregation.
基金Supported by the National Natural Science Foundation of China (Nos.42130410,41620104001,41976133)the Fundamental Research Funds for the Central Universities (No.202061013)。
文摘Microorganisms in sediments are critical to marine ecosystems.The microbial communities in marine sediments of the Bohai Sea(BS)and Yellow Sea(YS),the eastern Chinese marginal seas,were uncovered in employing the metagenomic approach.In addition,the taxonomic and functional compositions of microbes were compared among various sediment core depths.Results showing the compositions,diversities,and functions of the microbial communities showed no significant variations with sea areas,and significant seasonal variations was observed in station 3500-7 only on functions of the microbial communities.Moreover,the compositions,diversities,and functions of the microbial communities changed noticeably in different sediment depths in close correlation with physical and chemical properties of sediments.However,the large fraction of the variation in functional communities remained unexplained.From bioinformatic analysis of the metagenomic data,the carbon-metabolismrelated genes such as glycosyl transferase(GT),glycoside hydrolase(GH),and carbohydrate esterase(CE)genes were rich in the microbial community,especially in the top sediment depth.Additionally,in this N-polluted habitat,nitrification and anaerobic ammonia oxidation(anammox)were dominant in the top sediment depth,whereas dissimilatory nitrate reduction to ammonium(DNRA)and denitrification were dominant in the middle and bottom depth,respectively.Further identification of possible biogeochemical links suggested that Gammaproteobacteria,Alphaproteobacteria,Nitrospirae,Nitrospinae,Chloroflexi,and Methanomicrobia might promote effective circulation of carbon and nitrogen cycling.This study expanded our knowledge about the structure and functional potential of microbial communities associated with different sediment depth,and provided further comprehensive information on element cycles in marine environments.
文摘为解决移动机器人在复杂地形场景的路径规划中易陷入局部最优和收敛速度慢等问题,提出了一种多策略集成的增强型人工大猩猩算法(enhanced artificial gorilla troops optimizer with integration of quadratic interpolation and elite individual genetic strategies,QGGTO)。融合二次插值策略和精英个体遗传策略,促进候选解之间的信息交流以加速收敛,并维持种群遗传多样性以避免局部最优。针对包含规则障碍物和不规则障碍物的复杂地形场景,构建了综合考虑行走距离、安全性和转向角度的成本函数,用于统一评估算法的路径规划性能。实验结果表明:QGGTO整体寻优性能优于GTO等7种竞争算法。在4种复杂障碍环境下,QGGTO能够辅助机器人规划出最接近全局最优的路径,验证了其在实际应用中的有效性。
