The interaction of multiple bubbles is a complex physical problem.A simplified case of multiple bubbles is studied theoretically with a bubble located at the center of a circular bubble cluster.All bubbles in the clus...The interaction of multiple bubbles is a complex physical problem.A simplified case of multiple bubbles is studied theoretically with a bubble located at the center of a circular bubble cluster.All bubbles in the cluster are equally spaced and own the same initial conditions as the central bubble.The unified theory for bubble dynamics[35]is applied to model the interaction between the central bubble and the circular bubble cluster.To account for the effect of the propagation time of pressure waves,the emission source of the wave is obtained by interpolating the physical information on the time axis.An underwater explosion experiment with two bubbles of different scales is used to validate the theoretical model.The effect of the bubble cluster with a variation in scale on the pulsation characteristics of the central bubble is studied.展开更多
n the area of naval architecture and ocean engineering,the research about the underwater xplosion problem is of great significance.To achieve prolonged simulation of near-free surface underwater explosion,the underwat...n the area of naval architecture and ocean engineering,the research about the underwater xplosion problem is of great significance.To achieve prolonged simulation of near-free surface underwater explosion,the underwater explosion transient numerical model is established in this paper based on compressible Eulerian finite element method(EFEM).Compared with Geers Hunter formula,EFEM is availably validated by simulating the free-field underwater xplosion case.Then,the bubble pulsation and flow field dynamic characteristics of the cases with different underwater explosive depth are compared in this work.Lastly,the height of the water hump and the pressure of flow flied are analyzed quantitatively through the simulation results.展开更多
We report 10 Gb/s data transmissions using a packaged two-section InGaAsP/InP distributed Bragg reflector(DBR)laser.The tunable DBR laser has a wavelength tuning range of 12.12 nm.The DBR laser has greater than 10.84 ...We report 10 Gb/s data transmissions using a packaged two-section InGaAsP/InP distributed Bragg reflector(DBR)laser.The tunable DBR laser has a wavelength tuning range of 12.12 nm.The DBR laser has greater than 10.84 GHz 3-dB direct modulation bandwidth within the wavelength tuning range.The 10 Gb/s data transmissions are performed at up to a distance of 30-km.展开更多
Numerous methods have been published to segment the infarct tissue in theleft ventricle, most of them either need manual work, post-processing, or suffer from poorreproducibility. We proposed an automatic segmentation...Numerous methods have been published to segment the infarct tissue in theleft ventricle, most of them either need manual work, post-processing, or suffer from poorreproducibility. We proposed an automatic segmentation method for segmenting the infarct tissue irleft ventricle with myocardial infarction. Cardiac images of a total of 60 diseased hearts (55 humanhearts and 5 porcine hearts) were used in this study. The epicardial and endocardial boundariesof the ventricles in every 2D slice of the cardiac magnetic resonance with late gadoliniumenhancement images were manually segmented. The subsequent pipeline of infarct tissuesegmentation is fully automatic. The segmentation results with the automatic algorithm proposed inthis paper were compared to the consensus ground truth. The median of Dice overlap between ourautomatic method and the consensus ground truth is 0.79. We also compared the automatic methodwith the consensus ground truth using different image sources from diferent centers with diferentscan parameters and different scan machines. The results showed that the Dice overlap with thepublic dataset was 0.83, and the overall Dice overlap was 0.79. The results show that our method isrobust with respect to different MRI image sources, which were scanned by different centers withdifferent image collection parameters. The segmentation accuracy we obtained is comparable toor better than that of the conventional semi-automatic methods. Our segmentation method may beuseful for processing large amount of dataset in clinic.展开更多
Dear Editor,Bamboos(Bambusoideae,Poaceae)are of significant economic and ecological importance,supporting billions of people and contributing to international trade(Wu et al.,2023).They play a crucial role in carbon f...Dear Editor,Bamboos(Bambusoideae,Poaceae)are of significant economic and ecological importance,supporting billions of people and contributing to international trade(Wu et al.,2023).They play a crucial role in carbon fixation and support a multitude of other species including the giant panda(Clark et al.,2015).Since the release of the first draft genome of moso bamboo(Phyllostachys edulis)(Peng et al.,2013),there has been a notable increase in the sequencing,assembly,and annotation of diverse bamboo genomes(Guo et al.,2019;Zheng et al.,2022;Ma et al.,2024).An existing resource for bamboo genomics,BambooGDB(Zhao et al.,2014),provides information based on the individual draft reference genome of moso bamboo.What is needed,however,is a resource reinforcing multiple genome assemblies in Bambusoideae to enable researchers to unravel the evolutionary history of chromosomes and genes through cladespecific comparative genomic investigations.Here,we present BambooBase(https://bamboo.genobank.org/),a newly developed web-based database designed to provide a seamless user experience for bamboo omics and systematics.展开更多
This paper aims to use the unified bubble dynamics equation to investigate bubble behavior in complex scenarios involving hybrid free surface/wall boundaries and interactions between multiple bubbles.The effect of sin...This paper aims to use the unified bubble dynamics equation to investigate bubble behavior in complex scenarios involving hybrid free surface/wall boundaries and interactions between multiple bubbles.The effect of singularity movement on the unified equation’s form is analyzed after deriving the bubble pulsation equation using a moving point source and a dipole,followed by discussions on the effect of migration compressibility-related terms on the bubble dynamics.In addition,the present study accounts for the impact of hybrid boundaries,including crossed and parallel boundaries,by introducing a finite number of mirror bubbles for the former and an infinite number of mirror bubbles for the latter.Spark bubble experiments and numerical simulation are conducted to validate the present theory.The application of the unified equation in multi-bubble interactions is exemplified by computing a spherical bubble array containing more than 100 uniformly distributed cavitation bubbles under different boundary conditions.The bubble cluster-induced pressure peak can reach nearly two times or even higher than that of an individual bubble,highlighting the damage potential caused by cavitation bubble clusters.展开更多
Tea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9...Tea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9%), 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.展开更多
Polyploidization is a major driver of speciation and its importance to plant evolution has been well recognized.Bamboos comprise one diploid herbaceous and three polyploid woody lineages,and are members of the only ma...Polyploidization is a major driver of speciation and its importance to plant evolution has been well recognized.Bamboos comprise one diploid herbaceous and three polyploid woody lineages,and are members of the only major subfamily in grasses that diversified in forests,with the woody members having a tree-like lignified culm.In this study,we generated four draft genome assemblies of major bamboo lineages with three different ploidy levels(diploid,tetraploid,and hexaploid).We also constructed a high-density genetic linkage map for a hexaploid species of bamboo,and used a linkage-map-based strategy for genome assembly and identification of subgenomes in polyploids.Further phylogenomic analyses using a large dataset of syntenic genes with expected copies based on ploidy levels revealed that woody bamboos originated subsequent to the divergence of the herbaceous bamboo lineage,and experienced complex reticulate evolution through three independent allopolyploid events involving four extinct diploid ancestors.A shared but distinct subgenome was identified in all polyploid forms,and the progenitor of this subgenome could have been critical in ancient polyploidizations and the origin of woody bamboos.Important genetic clues to the unique flowering behavior and woody trait in bamboos were also found.Taken together,our study provides significant insights into ancient reticulate evolution at the subgenome level in the absence of extant donor species,and offers a potential model scenario for broad-scale study of angiosperm origination by allopolyploidization.展开更多
The rubber tree,Hevea brasiliensis,produces natural rubber that serves as an essential industrial raw material.Here,we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-...The rubber tree,Hevea brasiliensis,produces natural rubber that serves as an essential industrial raw material.Here,we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-time sequencing(SMRT)and Hi-C technologies to anchor the~1.47-Gb genome assembly into 18 pseudochromosomes.The chromosome-based genome analysis enabled us to establish a model of spurge chromosome evolution,since the common paleopolyploid event occurred before the split of Hevea and Manihot.We show recent and rapid bursts of the three Hevea-specific LTR-retrotransposon families during the last 10 million years,leading to the massive expansion by~65.88%(~970 Mbp)of the whole rubber tree genome since the divergence from Manihot.We identify large-scale expansion of genes associated with whole rubber biosynthesis processes,such as basal metabolic processes,ethylene biosynthesis,and the activation of polysaccharide and glycoprotein lectin,which are important properties for latex production.A map of genomic variation between the cultivated and wild rubber trees was obtained,which contains~15.7 million high-quality single-nucleotide polymorphisms.We identified hundreds of candidate domestication genes with drastically lowered genomic diversity in the cultivated but not wild rubber trees despite a relatively short domestication history of rubber tree,some of which are involved in rubber biosynthesis.This genome assembly represents key resources for future rubber tree research and breeding,providing novel targets for improving plant biotic and abiotic tolerance and rubber production.展开更多
Bubbles have very important applications in many fields such as shipbuilding engineering, ocean engineering, mechanical engineering, environmental engineering, chemical engineering, medical science and so on. In this ...Bubbles have very important applications in many fields such as shipbuilding engineering, ocean engineering, mechanical engineering, environmental engineering, chemical engineering, medical science and so on. In this paper, the research status and the development of the bubble dynamics in terms of theory, numerical simulation and experimental technique are reviewed, which cover the underwater explosion bubble, airgun bubble, spark bubble, laser bubble, rising bubble, propeller cavitation bubble, water entry/exit cavitation bubble and bubble dynamics in other fields. Former researchers have done a lot of researches on bubble dynamics and gained fruitful achievements. However, due to the complexity of the bubble motion, many tough mechanical problems remain to be solved. Based on the research progress of bubble dynamics, this paper gives the future research direction of bubble dynamics, aiming to provide references for researches related to bubble dynamics.展开更多
In this paper,the dynamic characteristics of the bubble in a broken confined domain are studied.The broken confined domain is composed of a solid wall and a plate that has a hole.The axisymmetric numerical model is es...In this paper,the dynamic characteristics of the bubble in a broken confined domain are studied.The broken confined domain is composed of a solid wall and a plate that has a hole.The axisymmetric numerical model is established by combining the Eulerian finite-element method with volume of fluid(VOF)method,and is validated by comparing the results with those from an experiment.Then the influences of the wall distance,plate distance and size of the hole are analyzed.The results show that cavity-attraction jet caused by the hole and annular jet caused by the upper solid wall compete with each other to dominate the bubble dynamics.The cavity-attraction jet develops earlier,but slower.Thus,jet load in the bubble stage is mainly generated by the annular jet with a higher impact speed.Within a certain range,the closer the hole is to the bubble or the smaller the hole,the longer the pulsation period of the bubble will be.展开更多
A family of tropos ligands bearing a N-heterocyclic carbene and a chiral oxazoline coordination group with a N-phenyl framework were easily prepared,and their coordination behavior with Pd(Ⅱ)acetate was performed,a...A family of tropos ligands bearing a N-heterocyclic carbene and a chiral oxazoline coordination group with a N-phenyl framework were easily prepared,and their coordination behavior with Pd(Ⅱ)acetate was performed,affording a series of axially chiral palladium complexes in good yields.展开更多
基金funded by the National Natural Science Founda-tion of China(51925904,52088102)the National Key R&D Program of China(2022YFC2803500,2018YFC0308900)+2 种基金Finance Science and Technology Project of Hainan Province(ZDKJ2021020)the Heilongjiang Provincial Natural Science Foundation of China(YQ2022E017)the Xplore Prize。
文摘The interaction of multiple bubbles is a complex physical problem.A simplified case of multiple bubbles is studied theoretically with a bubble located at the center of a circular bubble cluster.All bubbles in the cluster are equally spaced and own the same initial conditions as the central bubble.The unified theory for bubble dynamics[35]is applied to model the interaction between the central bubble and the circular bubble cluster.To account for the effect of the propagation time of pressure waves,the emission source of the wave is obtained by interpolating the physical information on the time axis.An underwater explosion experiment with two bubbles of different scales is used to validate the theoretical model.The effect of the bubble cluster with a variation in scale on the pulsation characteristics of the central bubble is studied.
基金The authors would like to acknowledge the support of the National Natural Science Foundation of China(Grant 11672081)the Industrial Technology Development Program(Grants JCKY2018604C010 and JCKY2017604C002).Finally,Thanks for the help of Zu-Hui Li during writing the paper.
文摘n the area of naval architecture and ocean engineering,the research about the underwater xplosion problem is of great significance.To achieve prolonged simulation of near-free surface underwater explosion,the underwater explosion transient numerical model is established in this paper based on compressible Eulerian finite element method(EFEM).Compared with Geers Hunter formula,EFEM is availably validated by simulating the free-field underwater xplosion case.Then,the bubble pulsation and flow field dynamic characteristics of the cases with different underwater explosive depth are compared in this work.Lastly,the height of the water hump and the pressure of flow flied are analyzed quantitatively through the simulation results.
基金Supported by the National Key Research and Development Program of China(Grant Nos.2017YFF0206103,2016YFB0402301,2018YFB2200801)the National Natural Science Foundation of China(Grant Nos.61635010,61320106013,61474112,and 61574137)。
文摘We report 10 Gb/s data transmissions using a packaged two-section InGaAsP/InP distributed Bragg reflector(DBR)laser.The tunable DBR laser has a wavelength tuning range of 12.12 nm.The DBR laser has greater than 10.84 GHz 3-dB direct modulation bandwidth within the wavelength tuning range.The 10 Gb/s data transmissions are performed at up to a distance of 30-km.
基金supported by the National Key Researchand Development Program of China(No.2016YFC1301002 to Jianzeng Dong)the National Natural Science Foundation of China(No.81901841 to Dongdong Deng,No.81671650 and No.81971569 to Yi He,No.61527811 to Ling Xia)+1 种基金the Key Research and Development Program of Zhejiang Province(No.2020C03016 to Ling Xia)Dongdong Deng also acknowledges support from Dalian University of Technology(No.DUT18RC(3)068)。
文摘Numerous methods have been published to segment the infarct tissue in theleft ventricle, most of them either need manual work, post-processing, or suffer from poorreproducibility. We proposed an automatic segmentation method for segmenting the infarct tissue irleft ventricle with myocardial infarction. Cardiac images of a total of 60 diseased hearts (55 humanhearts and 5 porcine hearts) were used in this study. The epicardial and endocardial boundariesof the ventricles in every 2D slice of the cardiac magnetic resonance with late gadoliniumenhancement images were manually segmented. The subsequent pipeline of infarct tissuesegmentation is fully automatic. The segmentation results with the automatic algorithm proposed inthis paper were compared to the consensus ground truth. The median of Dice overlap between ourautomatic method and the consensus ground truth is 0.79. We also compared the automatic methodwith the consensus ground truth using different image sources from diferent centers with diferentscan parameters and different scan machines. The results showed that the Dice overlap with thepublic dataset was 0.83, and the overall Dice overlap was 0.79. The results show that our method isrobust with respect to different MRI image sources, which were scanned by different centers withdifferent image collection parameters. The segmentation accuracy we obtained is comparable toor better than that of the conventional semi-automatic methods. Our segmentation method may beuseful for processing large amount of dataset in clinic.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000)the Fundamental Research Project of Yunnan Province(202101AT070175)+2 种基金the National Natural Science Foundation of China(32120103003)Digitalization,Development and Application of Biotic Resources(202002AA100007)a grant for Reserve Talents for Young and Middle-aged Academic and Technological Leaders in Yunnan Province,China(202405AC350089).
文摘Dear Editor,Bamboos(Bambusoideae,Poaceae)are of significant economic and ecological importance,supporting billions of people and contributing to international trade(Wu et al.,2023).They play a crucial role in carbon fixation and support a multitude of other species including the giant panda(Clark et al.,2015).Since the release of the first draft genome of moso bamboo(Phyllostachys edulis)(Peng et al.,2013),there has been a notable increase in the sequencing,assembly,and annotation of diverse bamboo genomes(Guo et al.,2019;Zheng et al.,2022;Ma et al.,2024).An existing resource for bamboo genomics,BambooGDB(Zhao et al.,2014),provides information based on the individual draft reference genome of moso bamboo.What is needed,however,is a resource reinforcing multiple genome assemblies in Bambusoideae to enable researchers to unravel the evolutionary history of chromosomes and genes through cladespecific comparative genomic investigations.Here,we present BambooBase(https://bamboo.genobank.org/),a newly developed web-based database designed to provide a seamless user experience for bamboo omics and systematics.
基金supported by the National Natural Science Foundation of China(Grant Nos.52088102,and 51925904)the National Key R&D Program of China(Grant Nos.2022YFC2803500,and 2018YFC0308900)+1 种基金the Finance Science and Technology Project of Hainan Province(Grant No.ZDKJ2021020)the Xplore Prize。
文摘This paper aims to use the unified bubble dynamics equation to investigate bubble behavior in complex scenarios involving hybrid free surface/wall boundaries and interactions between multiple bubbles.The effect of singularity movement on the unified equation’s form is analyzed after deriving the bubble pulsation equation using a moving point source and a dipole,followed by discussions on the effect of migration compressibility-related terms on the bubble dynamics.In addition,the present study accounts for the impact of hybrid boundaries,including crossed and parallel boundaries,by introducing a finite number of mirror bubbles for the former and an infinite number of mirror bubbles for the latter.Spark bubble experiments and numerical simulation are conducted to validate the present theory.The application of the unified equation in multi-bubble interactions is exemplified by computing a spherical bubble array containing more than 100 uniformly distributed cavitation bubbles under different boundary conditions.The bubble cluster-induced pressure peak can reach nearly two times or even higher than that of an individual bubble,highlighting the damage potential caused by cavitation bubble clusters.
基金This work was supported by the project of Yunnan Innovation Team Project, the Hundreds Oversea Talents Program of Yunnan Province, the Top Talents Program of Yunnan Province (Grant 20080A009), the Key Project of the Natural Science Foundation of Yunnan Province (201401 PC00397), National Science Foundation of China (U0936603), Key Project of Natural Science Foundation of Yunnan Province (2008CC016), Frontier Grant of Kunming Institute of Botany, CAS (672705232515), Top Talents Program of Yunnan Province (20080A009), and Hundreds Talents Program of Chinese Academy of Sciences (CAS) (to L.G.).
文摘Tea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9%), 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.
基金funding from Strategic Priority Program of the Chinese Academy of Sciences(CAS)(XDB31000000 to D.-Z.L)the National Natural Science Foundation of China(grants 31430011 to D.-Z.L.and 31670227 to Z.-H.G.)+3 种基金Leading Talents Program of Yunnan Province(2017HA014 to D.-Z.L.)CAS Youth Innovation Promotion Association(2015321 to P.-F.M.)a grant from Germplasm Bank of Wild Species(Y77P4412Z1 to Z.-H.G.)CAS Pioneer Hundred Talents Program(292015312D11035 to J.-Y.H.).
文摘Polyploidization is a major driver of speciation and its importance to plant evolution has been well recognized.Bamboos comprise one diploid herbaceous and three polyploid woody lineages,and are members of the only major subfamily in grasses that diversified in forests,with the woody members having a tree-like lignified culm.In this study,we generated four draft genome assemblies of major bamboo lineages with three different ploidy levels(diploid,tetraploid,and hexaploid).We also constructed a high-density genetic linkage map for a hexaploid species of bamboo,and used a linkage-map-based strategy for genome assembly and identification of subgenomes in polyploids.Further phylogenomic analyses using a large dataset of syntenic genes with expected copies based on ploidy levels revealed that woody bamboos originated subsequent to the divergence of the herbaceous bamboo lineage,and experienced complex reticulate evolution through three independent allopolyploid events involving four extinct diploid ancestors.A shared but distinct subgenome was identified in all polyploid forms,and the progenitor of this subgenome could have been critical in ancient polyploidizations and the origin of woody bamboos.Important genetic clues to the unique flowering behavior and woody trait in bamboos were also found.Taken together,our study provides significant insights into ancient reticulate evolution at the subgenome level in the absence of extant donor species,and offers a potential model scenario for broad-scale study of angiosperm origination by allopolyploidization.
基金supported by Yunnan Innovation Team Project and the start-up grant from South China Agricultural University(to L.G.).
文摘The rubber tree,Hevea brasiliensis,produces natural rubber that serves as an essential industrial raw material.Here,we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-time sequencing(SMRT)and Hi-C technologies to anchor the~1.47-Gb genome assembly into 18 pseudochromosomes.The chromosome-based genome analysis enabled us to establish a model of spurge chromosome evolution,since the common paleopolyploid event occurred before the split of Hevea and Manihot.We show recent and rapid bursts of the three Hevea-specific LTR-retrotransposon families during the last 10 million years,leading to the massive expansion by~65.88%(~970 Mbp)of the whole rubber tree genome since the divergence from Manihot.We identify large-scale expansion of genes associated with whole rubber biosynthesis processes,such as basal metabolic processes,ethylene biosynthesis,and the activation of polysaccharide and glycoprotein lectin,which are important properties for latex production.A map of genomic variation between the cultivated and wild rubber trees was obtained,which contains~15.7 million high-quality single-nucleotide polymorphisms.We identified hundreds of candidate domestication genes with drastically lowered genomic diversity in the cultivated but not wild rubber trees despite a relatively short domestication history of rubber tree,some of which are involved in rubber biosynthesis.This genome assembly represents key resources for future rubber tree research and breeding,providing novel targets for improving plant biotic and abiotic tolerance and rubber production.
基金Project supported by the National Key Research and Development Projects(Grand No.2018YFC0308900)the National Natural Science Foundation of China(Grand No.11672082)
文摘Bubbles have very important applications in many fields such as shipbuilding engineering, ocean engineering, mechanical engineering, environmental engineering, chemical engineering, medical science and so on. In this paper, the research status and the development of the bubble dynamics in terms of theory, numerical simulation and experimental technique are reviewed, which cover the underwater explosion bubble, airgun bubble, spark bubble, laser bubble, rising bubble, propeller cavitation bubble, water entry/exit cavitation bubble and bubble dynamics in other fields. Former researchers have done a lot of researches on bubble dynamics and gained fruitful achievements. However, due to the complexity of the bubble motion, many tough mechanical problems remain to be solved. Based on the research progress of bubble dynamics, this paper gives the future research direction of bubble dynamics, aiming to provide references for researches related to bubble dynamics.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFC0308900)the National Natural Science Foundation of China(Grant Nos.51879050,51925904).
文摘In this paper,the dynamic characteristics of the bubble in a broken confined domain are studied.The broken confined domain is composed of a solid wall and a plate that has a hole.The axisymmetric numerical model is established by combining the Eulerian finite-element method with volume of fluid(VOF)method,and is validated by comparing the results with those from an experiment.Then the influences of the wall distance,plate distance and size of the hole are analyzed.The results show that cavity-attraction jet caused by the hole and annular jet caused by the upper solid wall compete with each other to dominate the bubble dynamics.The cavity-attraction jet develops earlier,but slower.Thus,jet load in the bubble stage is mainly generated by the annular jet with a higher impact speed.Within a certain range,the closer the hole is to the bubble or the smaller the hole,the longer the pulsation period of the bubble will be.
基金the National Natural Science Foundation of China for financial support (Nos. 21372075 and 61376003)
文摘A family of tropos ligands bearing a N-heterocyclic carbene and a chiral oxazoline coordination group with a N-phenyl framework were easily prepared,and their coordination behavior with Pd(Ⅱ)acetate was performed,affording a series of axially chiral palladium complexes in good yields.