Seed weight is a component of seed yield in rapeseed(Brassica napus L.).Although quantitative trait loci(QTL)for seed weight have been reported in rapeseed,only a few causal quantitative trait genes(QTGs)have been ide...Seed weight is a component of seed yield in rapeseed(Brassica napus L.).Although quantitative trait loci(QTL)for seed weight have been reported in rapeseed,only a few causal quantitative trait genes(QTGs)have been identified,resulting in a limitation in understanding of seed weight regulation.We constructed a gene coexpression network at the early seed developmental stage using transcripts of 20,408 genes in QTL intervals and 1017 rapeseed homologs of known genes from other species.Among the 10 modules in this gene coexpression network,modules 1 and 2 were core modules and contained genes involved in source–flow–sink processes such as synthesis and transportation of fatty acid and protein,and photosynthesis.A hub gene SERINE CARBOXYPEPTIDASE-LIKE 19(SCPL19)was identified by candidate gene association analysis in rapeseed and functionally investigated using Arabidopsis T-DNA mutant and overexpression lines.Our study demonstrates the power of gene coexpression analysis to prioritize candidate genes from large candidate QTG sets and enhances the understanding of molecular mechanism for seed weight at the early developmental stage in rapeseed.展开更多
Seed number per silique(SNPS)is one of seed yield components in rapeseed,but its genetic mechanism remains elusive.Here a double haploid(DH)population derived from a hybrid between female 6Q006with 35–40 SNPS and mal...Seed number per silique(SNPS)is one of seed yield components in rapeseed,but its genetic mechanism remains elusive.Here a double haploid(DH)population derived from a hybrid between female 6Q006with 35–40 SNPS and male 6W26 with 10–15 SNPS was investigated for SNPS in the year 2017,2018,2019 and 2021,and genotyped with Brassica 60K Illumina Infinium SNP array.An overlapping major QTL(qSNPS.C09)explaining 51.50%of phenotypic variance on average was narrowed to a 0.90 Mb region from 44.87 Mb to 45.77 Mb on chromosome C09 by BSA-seq.Subsequently,two DEGs in this interval were detected between extreme individuals in DH and F_2populations by transcriptome sequencing at7 and 14 days after pollination siliques.Of which,BnaC09g45400D encoded an adenine phosphoribosyltransferase 5(APT5)has a 48-bp InDel variation in the promoter of two parents.Candidate gene association analysis showed that this InDel variation was associated with SNPS in a nature population of rapeseed,where 54 accessions carrying the same haplotype as parent 6Q006 had higher SNPS than103 accessions carrying the same haplotype as parent 6W26.Collectively,the findings are helpful for rapeseed molecular breeding of SNPS,and provide new insight into the genetic and molecular mechanism of SNPS in rapeseed.展开更多
Under the guidance of strain tolerance, a new combination method for crude oil-degrading bacterial consortium was studied. Firstly, more than 50 efficient crude oil-degrading and biosurfactant producing bacteria were ...Under the guidance of strain tolerance, a new combination method for crude oil-degrading bacterial consortium was studied. Firstly, more than 50 efficient crude oil-degrading and biosurfactant producing bacteria were isolated from petroleum-contaminated soil and water in Tianjin Binhai New Area Oil field, China. Twenty-four of them were selected for further study. These strains were identified as belonging Pseudornonas aeruginosa, Bacillus subtilis, Brevibacillus brevis, Achrornobacter sp., Acinetobacter venetianus, Lysinibacillus rnacroides, Klebsiella oxytoca, Stenotrophornonas rhizophila, Rhodococcus sp. and Bacillus thuringiensis. A shake-flask degradation test revealed that 12 of these strains could degrade over 50% of 1% crude oil concentration in 7 d. Of these, 8 strains were able to produce biosurfactants. Furthermore, environmental tolerance experiments indicated that the majority of the strains had the ability to adapt to extreme environments including high temperatures, alkaline en- vironments and high salinity environments. A mixed bacterial agent comprising the strains WB2, W2, W3 and HA was developed based on the environmental tolerance tests and subjected to the pilot-scale degradation test indicating that this bacterial agent could degrade 85.2% of 0.8% crude oil concentration in 60 d. Our results suggest that the application of this mixed agent could remediate crude oil polluted soils in saline and alkaline environments.展开更多
The methane bubble plume attracts interest because it offers direct evidence of seafloor gas leakage and plays an indirect role in the exploration and identification of natural gas hydrate.In this study,based on estab...The methane bubble plume attracts interest because it offers direct evidence of seafloor gas leakage and plays an indirect role in the exploration and identification of natural gas hydrate.In this study,based on established plume models and their migration sections,three amplitude-class attributes were extracted from three formations for the migration sections of five plumes,and the correlation between the gas content and seismic attribute was obtained.As the gas content increases,the amplitude attribute correspondingly increases,and the linear correlation is relatively good.Moreover,correlation coefficients between gas content and amplitude attributes are close to 1.0.By using linear fitting,the relation model between the gas content of the plume and the seismic attribute was obtained.The relation model was subsequently used to invert the gas content from a real databearing plume.Comparison of the gas content section of the plume with the attribute section and real seismic section reveals common distribution characteristics,namely,the color of the section in the lower right corner is dark.If the amplitude value is large in the seismic section of the real plume,the amplitude attribute value is also large in the corresponding attribute section,and the inverted value of the gas content is also large(because gas content and amplitude are linearly correlated),which indicates that the plume bubbles of the section in the lower right corner is intensively distributed.Finally,the obtained gas content section of the plume can reflect the distribution of the plume bubble content more simply and intuitively,from which the distribution law of seafloor bubbles can be deduced,and this lays a foundation for the further estimation of the gas content of the plume and hydrate reserves.展开更多
Over the past decades,sea ice in the polar regions has been significantly affecting local and even hemispheric climate through a positive ice albedo feedback mechanism.The role of fast ice,as opposed to drift ice,has ...Over the past decades,sea ice in the polar regions has been significantly affecting local and even hemispheric climate through a positive ice albedo feedback mechanism.The role of fast ice,as opposed to drift ice,has not been well-studied due to its relatively small coverage over the earth.In this paper,the optical properties and surface energy balance of land fast ice in spring are studied using in situ observations in Barrow,Alaska.The results show that the albedo of the fast ice varied between 0.57 and 0.85 while the transmittance increased from 1.3×10-3 to 4.1×10-3 during the observation period.Snowfall and air temperature affected the albedo and absorbance of sea ice,but the transmittance had no obvious relationship with precipitation or snow cover.Net solar shortwave radiation contributes to the surface energy balance with a positive 99.2%of the incident flux,with sensible heat flux for the remaining 0.8%.Meanwhile,the ice surface loses energy through the net longwave radiation by 18.7%of the total emission,while the latent heat flux accounts for only 0.1%.Heat conduction is also an important factor in the overall energy budget of sea ice,contributing 81.2%of the energy loss.Results of the radiative transfer model reveal that the spectral transmittance of the fast ice is determined by the thickness of snow and sea ice as well as the amount of inclusions.As major inclusions,the ice biota and particulates have a significant influence on the magnitude and distribution of the spectral transmittance.Based on the radiative transfer model,concentrations of chlorophyll and particulate in the fast ice are estimated at 5.51 mg/m^(2)and 95.79 g/m^(2),which are typical values in the spring in Barrow.展开更多
Graphene’s optical absorption coefficient increases linearly with the number of layers making it more effective in the construction of optical tuning graphene-based devices. Refractive index(RI) is one of the importa...Graphene’s optical absorption coefficient increases linearly with the number of layers making it more effective in the construction of optical tuning graphene-based devices. Refractive index(RI) is one of the important optical parameters of the graphene for accurately describing its optical characteristics and further applications. In view of the RI research of the multilayer graphene is lacking and existing measurement methods are complicated. Optical power tuning RI of multilayer graphene is investigated using a simple measurement and no temperature cross sensitivity all optical fiber sensing structure.Optical power tuning RI characteristics of multilayer graphene are studied by tuning the introducing broad band light power from 0.57 mW to 22.7 m W. Different thickness graphene coating shows different tuning efficiency. At 4.86-μm thickness,a 3.433-nm Bragg wavelength shift is obtained with 156.2-pm/mW wavelength versus optical power tuning sensitivity corresponding to 3.25×10~3 RI change and 0.154 URI/W(URI, unit of RI) RI optical power tuning efficiency.展开更多
Oceanic vertical mixing of the lower halocline water(LHW)in the Chukchi Borderland and Mendeleyev Ridge was studied based on in situ hydrographic and turbulent observations.The depth-averaged turbulent dissipation rat...Oceanic vertical mixing of the lower halocline water(LHW)in the Chukchi Borderland and Mendeleyev Ridge was studied based on in situ hydrographic and turbulent observations.The depth-averaged turbulent dissipation rate of LHW demonstrates a clear topographic dependence,with a mean value of 1.2×10^(-9) W/kg in the southwest of Canada Basin,1.5×10^(-9) W/kg in the Mendeleyev Abyssal Plain,2.4×10^(-9) W/kg on the Mendeleyev Ridge,and2.7×10^(-9) W/kg on the Chukchi Cap.Correspondingly,the mean depth-averaged vertical heat flux of the LHW is0.21 W/m^(2) in the southwest Canada Basin,0.30 W/m^(2) in the Mendeleyev Abyssal Plain,0.39 W/m^(2) on the Mendeleyev Ridge,and 0.46 W/m^(2) on the Chukchi Cap.However,in the presence of Pacific Winter Water,the upward heat released from Atlantic Water through the lower halocline can hardly contribute to the surface ocean.Further,the underlying mechanisms of diapycnal mixing in LHW—double diffusion and shear instability—was investigated.The mixing in LHW where double diffusion were observed is always relatively weaker,with corresponding dissipation rate ranging from 1.01×10^(-9) W/kg to 1.57×10^(-9) W/kg.The results also show a strong correlation between the depth-average dissipation rate and strain variance in the LHW,which indicates a close physical linkage between the turbulent mixing and internal wave activities.In addition,both surface wind forcing and semidiurnal tides significantly contribute to the turbulent mixing in the LHW.展开更多
As a part of certain region,agricultural development has inevitable connection with regional urbanization,and they are highly heterogeneous and complementary in space. Their internal relationship is manifested as agri...As a part of certain region,agricultural development has inevitable connection with regional urbanization,and they are highly heterogeneous and complementary in space. Their internal relationship is manifested as agricultural structure suits demand of urbanization development through adjustment in the process of urbanization,while urbanization is based on development of regional agriculture. From history of world agriculture and urbanization development,agriculture firstly provides primitive accumulation for urbanization development,and drives regional urbanization through promoting agricultural development. When urbanization develops to certain stage,urbanization accumulation increases and reaches the goal of " boosting urbanization through agriculture". If urbanization develops slowly,agricultural adjustment will lack motive force. On the contrary,weak agricultural development will lead to stagnation of urbanization. Therefore,adjustment of agricultural structure and urbanization development are interconnected,mutually promoted and restricted,and interdependent.展开更多
Background In recent decades,unmanned aerial vehicles(UAVs)have developed rapidly and been widely applied in many domains,including photography,reconstruction,monitoring,and search and rescue.In such applications,one ...Background In recent decades,unmanned aerial vehicles(UAVs)have developed rapidly and been widely applied in many domains,including photography,reconstruction,monitoring,and search and rescue.In such applications,one key issue is path and view planning,which tells UAVs exactly where to fly and how to search.Methods With specific consideration for three popular UAV applications(scene reconstruction,environment exploration,and aerial cinematography),we present a survey that should assist researchers in positioning and evaluating their works in the context of existing solutions.Results/Conclusions It should also help newcomers and practitioners in related fields quickly gain an overview of the vast literature.In addition to the current research status,we analyze and elaborate on advantages,disadvantages,and potential explorative trends for each application domain.展开更多
This work describes intermolecular acylfluorination of gem-difluoroenynes using acyl fluorides as both acyl source and fluorine source.Trifluoromethyl-substituted allenones or furans could be selectively achieved via ...This work describes intermolecular acylfluorination of gem-difluoroenynes using acyl fluorides as both acyl source and fluorine source.Trifluoromethyl-substituted allenones or furans could be selectively achieved via phosphine and silver catalysis.These approaches exhibit high regioselectivity,atom econ-omy and broad functionality tolerance.展开更多
Surface acoustic wave(SAW)resonators based on lithium tantalate(LT,LiTaO_(3))wafers are crucial elements of mobile communication filters.The use of intrinsic LT wafers typically brings about low fabrication accuracy o...Surface acoustic wave(SAW)resonators based on lithium tantalate(LT,LiTaO_(3))wafers are crucial elements of mobile communication filters.The use of intrinsic LT wafers typically brings about low fabrication accuracy of SAW resonators due to strong UV reflection in the lithography process.This hinders their resonance frequency control seriously in industrial manufacture.LT doping and chemical reduction could be applied to decrease the UV reflection of LT wafers for high lithographic precision.However,conventional methods fail to provide a fast and nondestructive approach to identify the UV performance of standard single-side polished LT wafers for highprecision frequency control.Here,we propose a convenient on-line sensing scheme based on the colorimetry of reduced Fe-doped LT wafers and build up an automatic testing system for industrial applications.The levels of Fe doping and chemical reduction are evaluated by the lightness and color difference of LT-based wafers.The correlation between the wafer visible colorimetry and UV reflection is established to refine the lithography process and specifically manipulate the frequency performance of SAW resonators.Our study provides a powerful tool for the fabrication control of SAW resonators and will inspire more applications on sophisticated devices of mobile communication.展开更多
Achieving efficient integration of cancer diagnosis and therapy is of great significance to human health,but the construction of a multifunctional intelligent therapy system still faces great challenges.In this study,...Achieving efficient integration of cancer diagnosis and therapy is of great significance to human health,but the construction of a multifunctional intelligent therapy system still faces great challenges.In this study,we report an integrated multifunctional nanocomposite constructed by a simple modular assembly technology.The nanocomposites are composed of three different nanomaterials:Fe_(3)O_(4),Au,and NaErF_(4):0.5%Tm@NaYF_(4)upconversion nanoparticles(UCNPs).In this design,Fe_(3)O_(4)nanoparticles have nanozyme effect of peroxidase-like activity,which can react with H_(2)O_(2)in the tumor microenvironment to generate hydroxyl radicals.Because of its magnetic properties,it can help the nanocomposites to aggregate under the induction of magnetic fields.Au nanoparticles exhibit nanozyme effect of glucose oxidase-like activity.It can catalyze the conversion of glucose to gluconic acid and H_(2)O_(2).Ingeniously,the generated H_(2)O_(2)provides a source of reactants for the reaction of the Fe_(3)O_(4)nanozyme.In addition,the photothermal effect of Au nanoparticles under 808 nm irradiation further enhanced the nanozyme activity of Fe_(3)O_(4)and Au nanoparticles.Besides,UCNPs can emit near-infrared(NIR)-II fluorescence under 808 nm irradiation,which can provide imaging-guided during cancer treatment.Then,the nanocomposites were further modified by poly(vinylpyrrolidone)(PVP)to obtain UCNPs/Au/Fe_(3)O_(4)-PVP with good biocompatibility and high-efficiency cancer treatment ability.展开更多
Small-molecule hydrogels based on amino acid derivatives have promising applications in many biological fields,including cell culture,drug delivery,and tissue engineering.Although these hydrogels have been widely repo...Small-molecule hydrogels based on amino acid derivatives have promising applications in many biological fields,including cell culture,drug delivery,and tissue engineering.Although these hydrogels have been widely reported to have low cytotoxicity,biocompatibility,and tunable bioactivity,problems such as harsh preparation conditions and complex material design hinder their application.Herein,by adjusting pH to induce non-covalent interactions between small-molecule tryptophan derivatives(N-[(phenylmethoxy)carbonyl]-L-tryptophan,Mw:338.35),we developed a self-assembled three-dimensional network hydrogel that can be rapidly formed in seconds.And the supramolecular self-assembly mechanism of the hydrogels was also investigated in detail through experimental characterizations and density functional theory calculation.As-prepared hydrogels also exhibit reversible pH-stimulated response and self-healing properties.This study details a research process for the simple and rapid preparation of tryptophan derivative-based hydrogels,which provides more reference ideas for the future development of materials based on other amino acid derivatives.展开更多
In the past few decades,significant progress in block copolymer self-assembly has been achieved in many fields,and with the development of nanoscience and nanotechnology,more and more complex situations need block cop...In the past few decades,significant progress in block copolymer self-assembly has been achieved in many fields,and with the development of nanoscience and nanotechnology,more and more complex situations need block copolymer self-assembly based nanoplatforms having more complex structures for specific multimodal or multiplexed applications.Through the combination of emulsification and self-assembly of the block copolymer,different materials with exotic architectures and functions could be combined within an entity,such as controlled vesicles,Janus particles,and composite particles which are more like ideal nanoplatforms.Various designs can show their different desired properties depending upon the application situation,including molecular delivery,surfactants,and multicolor encoding.This review will provide a complete summary of the optimization and the synthesis method for the recently designed emulsion confined block copolymer assemblies,and also the challenges and limitations this method faces,and the potential solutions in this field.展开更多
Photodynamic therapy(PDT)has emerged as an efficient treatment for cancers in recent years.However,PDT is limited by low utilization of photosensitizers and tumor hypoxia.The short lifetime and diffusion radius of sin...Photodynamic therapy(PDT)has emerged as an efficient treatment for cancers in recent years.However,PDT is limited by low utilization of photosensitizers and tumor hypoxia.The short lifetime and diffusion radius of singlet oxygen(^(1)O_(2))further decrease the anticancer effect of PDT.Herein,we design and synthesize diameter-controllable photosensitizer nanoparticles(NPs)which can specifically accumulate on the mitochondria of cancer cells and increase the O_(2) concentrations nearby to enhance PDT efficacy.Catalase(CAT)molecules are initially conjugated with rose bengal(RB)via amide bonds and then self-assembled into CAT-RB NPs.The NPs show excellent enzyme activity in catalyzing the decomposition of hydrogen peroxide into O_(2),which makes the yield of 1O21.65-fold higher than that of free RB.The intracellular uptake efficiency of NPs is increased by up to 150 times compared with pure RB.After endocytosis,the NPs mainly located at mitochondria and ^(1)O_(2) can directly destroy mitochondria under irradiation,thereby greatly decreasing the production of adenosine triphosphate and further leading to the apoptosis of cancer cells.Moreover,CAT-RB NPs can accumulate in tumors and show excellent PDT effects in vivo.This work opens a unique path to break through the current limitations of PDT in cancer treatment.展开更多
基金provided by the National Natural Science Foundation of China(32201776)the Natural Science Foundation of Chongqing(cstc2019jcyj-bsh X0055,cstc2019jcyj-zdxm X0012)。
文摘Seed weight is a component of seed yield in rapeseed(Brassica napus L.).Although quantitative trait loci(QTL)for seed weight have been reported in rapeseed,only a few causal quantitative trait genes(QTGs)have been identified,resulting in a limitation in understanding of seed weight regulation.We constructed a gene coexpression network at the early seed developmental stage using transcripts of 20,408 genes in QTL intervals and 1017 rapeseed homologs of known genes from other species.Among the 10 modules in this gene coexpression network,modules 1 and 2 were core modules and contained genes involved in source–flow–sink processes such as synthesis and transportation of fatty acid and protein,and photosynthesis.A hub gene SERINE CARBOXYPEPTIDASE-LIKE 19(SCPL19)was identified by candidate gene association analysis in rapeseed and functionally investigated using Arabidopsis T-DNA mutant and overexpression lines.Our study demonstrates the power of gene coexpression analysis to prioritize candidate genes from large candidate QTG sets and enhances the understanding of molecular mechanism for seed weight at the early developmental stage in rapeseed.
基金supported by the National Basic Research Program of China(2015CB150201)the Natural Science Foundation of Chongqing(cstc2019jcyj-bshX0055,cstc2019jcyj-zdxmX0012cstc2020jcyj-msxmX0461)。
文摘Seed number per silique(SNPS)is one of seed yield components in rapeseed,but its genetic mechanism remains elusive.Here a double haploid(DH)population derived from a hybrid between female 6Q006with 35–40 SNPS and male 6W26 with 10–15 SNPS was investigated for SNPS in the year 2017,2018,2019 and 2021,and genotyped with Brassica 60K Illumina Infinium SNP array.An overlapping major QTL(qSNPS.C09)explaining 51.50%of phenotypic variance on average was narrowed to a 0.90 Mb region from 44.87 Mb to 45.77 Mb on chromosome C09 by BSA-seq.Subsequently,two DEGs in this interval were detected between extreme individuals in DH and F_2populations by transcriptome sequencing at7 and 14 days after pollination siliques.Of which,BnaC09g45400D encoded an adenine phosphoribosyltransferase 5(APT5)has a 48-bp InDel variation in the promoter of two parents.Candidate gene association analysis showed that this InDel variation was associated with SNPS in a nature population of rapeseed,where 54 accessions carrying the same haplotype as parent 6Q006 had higher SNPS than103 accessions carrying the same haplotype as parent 6W26.Collectively,the findings are helpful for rapeseed molecular breeding of SNPS,and provide new insight into the genetic and molecular mechanism of SNPS in rapeseed.
基金Supported by the National Basic Research Program of China(“973”Program:2014CB745100)the National Natural Science Foundation of China(21576197)+2 种基金Tianjin Research Program of Application Foundation and Advanced Technology(14JCQNJC06700)the Major Research Plan of Tianjin(16YFXTSF00460)Tianjin Penglai 19-3 Oil Spill Accident Compensation Project(19-3BC2014-03)
文摘Under the guidance of strain tolerance, a new combination method for crude oil-degrading bacterial consortium was studied. Firstly, more than 50 efficient crude oil-degrading and biosurfactant producing bacteria were isolated from petroleum-contaminated soil and water in Tianjin Binhai New Area Oil field, China. Twenty-four of them were selected for further study. These strains were identified as belonging Pseudornonas aeruginosa, Bacillus subtilis, Brevibacillus brevis, Achrornobacter sp., Acinetobacter venetianus, Lysinibacillus rnacroides, Klebsiella oxytoca, Stenotrophornonas rhizophila, Rhodococcus sp. and Bacillus thuringiensis. A shake-flask degradation test revealed that 12 of these strains could degrade over 50% of 1% crude oil concentration in 7 d. Of these, 8 strains were able to produce biosurfactants. Furthermore, environmental tolerance experiments indicated that the majority of the strains had the ability to adapt to extreme environments including high temperatures, alkaline en- vironments and high salinity environments. A mixed bacterial agent comprising the strains WB2, W2, W3 and HA was developed based on the environmental tolerance tests and subjected to the pilot-scale degradation test indicating that this bacterial agent could degrade 85.2% of 0.8% crude oil concentration in 60 d. Our results suggest that the application of this mixed agent could remediate crude oil polluted soils in saline and alkaline environments.
基金The Innovation and Enhancing School Project of Guangdong Ocean University under contract No.230419096the Joint Research on Exploration and Development Technology of Natural Gas Hydrate under contract No.2018YFE0208200+2 种基金the Teaching Team Project of Guangdong Ocean University under contract No.570220033the National Natural Science Fundation of China under contract Nos 42004103 and 41306050the Fund of Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)under contract No.ZJW-2019-08。
文摘The methane bubble plume attracts interest because it offers direct evidence of seafloor gas leakage and plays an indirect role in the exploration and identification of natural gas hydrate.In this study,based on established plume models and their migration sections,three amplitude-class attributes were extracted from three formations for the migration sections of five plumes,and the correlation between the gas content and seismic attribute was obtained.As the gas content increases,the amplitude attribute correspondingly increases,and the linear correlation is relatively good.Moreover,correlation coefficients between gas content and amplitude attributes are close to 1.0.By using linear fitting,the relation model between the gas content of the plume and the seismic attribute was obtained.The relation model was subsequently used to invert the gas content from a real databearing plume.Comparison of the gas content section of the plume with the attribute section and real seismic section reveals common distribution characteristics,namely,the color of the section in the lower right corner is dark.If the amplitude value is large in the seismic section of the real plume,the amplitude attribute value is also large in the corresponding attribute section,and the inverted value of the gas content is also large(because gas content and amplitude are linearly correlated),which indicates that the plume bubbles of the section in the lower right corner is intensively distributed.Finally,the obtained gas content section of the plume can reflect the distribution of the plume bubble content more simply and intuitively,from which the distribution law of seafloor bubbles can be deduced,and this lays a foundation for the further estimation of the gas content of the plume and hydrate reserves.
基金The National Major Research High Resolution Sea Ice Model Development Program of China under contract No.2018YFA0605903the National Natural Science Foundation of China under contract No.41776192the Fundamental Research Funds for the Central Universities under contract No.202165005。
文摘Over the past decades,sea ice in the polar regions has been significantly affecting local and even hemispheric climate through a positive ice albedo feedback mechanism.The role of fast ice,as opposed to drift ice,has not been well-studied due to its relatively small coverage over the earth.In this paper,the optical properties and surface energy balance of land fast ice in spring are studied using in situ observations in Barrow,Alaska.The results show that the albedo of the fast ice varied between 0.57 and 0.85 while the transmittance increased from 1.3×10-3 to 4.1×10-3 during the observation period.Snowfall and air temperature affected the albedo and absorbance of sea ice,but the transmittance had no obvious relationship with precipitation or snow cover.Net solar shortwave radiation contributes to the surface energy balance with a positive 99.2%of the incident flux,with sensible heat flux for the remaining 0.8%.Meanwhile,the ice surface loses energy through the net longwave radiation by 18.7%of the total emission,while the latent heat flux accounts for only 0.1%.Heat conduction is also an important factor in the overall energy budget of sea ice,contributing 81.2%of the energy loss.Results of the radiative transfer model reveal that the spectral transmittance of the fast ice is determined by the thickness of snow and sea ice as well as the amount of inclusions.As major inclusions,the ice biota and particulates have a significant influence on the magnitude and distribution of the spectral transmittance.Based on the radiative transfer model,concentrations of chlorophyll and particulate in the fast ice are estimated at 5.51 mg/m^(2)and 95.79 g/m^(2),which are typical values in the spring in Barrow.
基金Project supported by the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2009AM017 and ZR2013FM019)the National Postdoctoral Project of China(Grant Nos.200902574 and 20080441150)+1 种基金the Fund from the Educational Department of Shandong Province,China(Grant No.J06P14)the Opening Foundation of State Key Laboratory of Minning Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology of China(Grant No.MDPC201602)
文摘Graphene’s optical absorption coefficient increases linearly with the number of layers making it more effective in the construction of optical tuning graphene-based devices. Refractive index(RI) is one of the important optical parameters of the graphene for accurately describing its optical characteristics and further applications. In view of the RI research of the multilayer graphene is lacking and existing measurement methods are complicated. Optical power tuning RI of multilayer graphene is investigated using a simple measurement and no temperature cross sensitivity all optical fiber sensing structure.Optical power tuning RI characteristics of multilayer graphene are studied by tuning the introducing broad band light power from 0.57 mW to 22.7 m W. Different thickness graphene coating shows different tuning efficiency. At 4.86-μm thickness,a 3.433-nm Bragg wavelength shift is obtained with 156.2-pm/mW wavelength versus optical power tuning sensitivity corresponding to 3.25×10~3 RI change and 0.154 URI/W(URI, unit of RI) RI optical power tuning efficiency.
基金The National Natural Science Foundation of China under contract No.42006037the Chinese Polar Environmental Comprehensive Investigation&Assessment Programs,Grant from the Scientific Research Fund of the Second Institute of Oceanography,MNR under contract No.JB904the National Key R&D Program of China under contract No.2019YFC1509102。
文摘Oceanic vertical mixing of the lower halocline water(LHW)in the Chukchi Borderland and Mendeleyev Ridge was studied based on in situ hydrographic and turbulent observations.The depth-averaged turbulent dissipation rate of LHW demonstrates a clear topographic dependence,with a mean value of 1.2×10^(-9) W/kg in the southwest of Canada Basin,1.5×10^(-9) W/kg in the Mendeleyev Abyssal Plain,2.4×10^(-9) W/kg on the Mendeleyev Ridge,and2.7×10^(-9) W/kg on the Chukchi Cap.Correspondingly,the mean depth-averaged vertical heat flux of the LHW is0.21 W/m^(2) in the southwest Canada Basin,0.30 W/m^(2) in the Mendeleyev Abyssal Plain,0.39 W/m^(2) on the Mendeleyev Ridge,and 0.46 W/m^(2) on the Chukchi Cap.However,in the presence of Pacific Winter Water,the upward heat released from Atlantic Water through the lower halocline can hardly contribute to the surface ocean.Further,the underlying mechanisms of diapycnal mixing in LHW—double diffusion and shear instability—was investigated.The mixing in LHW where double diffusion were observed is always relatively weaker,with corresponding dissipation rate ranging from 1.01×10^(-9) W/kg to 1.57×10^(-9) W/kg.The results also show a strong correlation between the depth-average dissipation rate and strain variance in the LHW,which indicates a close physical linkage between the turbulent mixing and internal wave activities.In addition,both surface wind forcing and semidiurnal tides significantly contribute to the turbulent mixing in the LHW.
基金Supported by Scientific Research Foundation of Hunan Provincial Department of Education(13B143)
文摘As a part of certain region,agricultural development has inevitable connection with regional urbanization,and they are highly heterogeneous and complementary in space. Their internal relationship is manifested as agricultural structure suits demand of urbanization development through adjustment in the process of urbanization,while urbanization is based on development of regional agriculture. From history of world agriculture and urbanization development,agriculture firstly provides primitive accumulation for urbanization development,and drives regional urbanization through promoting agricultural development. When urbanization develops to certain stage,urbanization accumulation increases and reaches the goal of " boosting urbanization through agriculture". If urbanization develops slowly,agricultural adjustment will lack motive force. On the contrary,weak agricultural development will lead to stagnation of urbanization. Therefore,adjustment of agricultural structure and urbanization development are interconnected,mutually promoted and restricted,and interdependent.
基金LHTD(20170003)and the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ).
文摘Background In recent decades,unmanned aerial vehicles(UAVs)have developed rapidly and been widely applied in many domains,including photography,reconstruction,monitoring,and search and rescue.In such applications,one key issue is path and view planning,which tells UAVs exactly where to fly and how to search.Methods With specific consideration for three popular UAV applications(scene reconstruction,environment exploration,and aerial cinematography),we present a survey that should assist researchers in positioning and evaluating their works in the context of existing solutions.Results/Conclusions It should also help newcomers and practitioners in related fields quickly gain an overview of the vast literature.In addition to the current research status,we analyze and elaborate on advantages,disadvantages,and potential explorative trends for each application domain.
基金support from the National Natural Science Foundation of China(Nos.21971107,22071101,22271147).
文摘This work describes intermolecular acylfluorination of gem-difluoroenynes using acyl fluorides as both acyl source and fluorine source.Trifluoromethyl-substituted allenones or furans could be selectively achieved via phosphine and silver catalysis.These approaches exhibit high regioselectivity,atom econ-omy and broad functionality tolerance.
基金Youth Talent Support Program of Fujian Province(Eyas Plan of Fujian Province)National Natural Science Foundation of China(62175205)Natural Science Foundation of Fujian Province(2020J06009)。
文摘Surface acoustic wave(SAW)resonators based on lithium tantalate(LT,LiTaO_(3))wafers are crucial elements of mobile communication filters.The use of intrinsic LT wafers typically brings about low fabrication accuracy of SAW resonators due to strong UV reflection in the lithography process.This hinders their resonance frequency control seriously in industrial manufacture.LT doping and chemical reduction could be applied to decrease the UV reflection of LT wafers for high lithographic precision.However,conventional methods fail to provide a fast and nondestructive approach to identify the UV performance of standard single-side polished LT wafers for highprecision frequency control.Here,we propose a convenient on-line sensing scheme based on the colorimetry of reduced Fe-doped LT wafers and build up an automatic testing system for industrial applications.The levels of Fe doping and chemical reduction are evaluated by the lightness and color difference of LT-based wafers.The correlation between the wafer visible colorimetry and UV reflection is established to refine the lithography process and specifically manipulate the frequency performance of SAW resonators.Our study provides a powerful tool for the fabrication control of SAW resonators and will inspire more applications on sophisticated devices of mobile communication.
基金This work was supported by the financial aid from the National Natural Science Foundation of China(Nos.22020102003,21834007,and 52103276)the National Key R&D Program of China(No.2020YFA0712102)+2 种基金the Program of Science and Technology Development Plan of Jilin Province of China(No.20220508076RC)the Natural Science Foundation of Guangdong Province of China(No.2022A1515010947)Guangzhou Basic and Applied Basic Research Foundation(No.202201011343).
文摘Achieving efficient integration of cancer diagnosis and therapy is of great significance to human health,but the construction of a multifunctional intelligent therapy system still faces great challenges.In this study,we report an integrated multifunctional nanocomposite constructed by a simple modular assembly technology.The nanocomposites are composed of three different nanomaterials:Fe_(3)O_(4),Au,and NaErF_(4):0.5%Tm@NaYF_(4)upconversion nanoparticles(UCNPs).In this design,Fe_(3)O_(4)nanoparticles have nanozyme effect of peroxidase-like activity,which can react with H_(2)O_(2)in the tumor microenvironment to generate hydroxyl radicals.Because of its magnetic properties,it can help the nanocomposites to aggregate under the induction of magnetic fields.Au nanoparticles exhibit nanozyme effect of glucose oxidase-like activity.It can catalyze the conversion of glucose to gluconic acid and H_(2)O_(2).Ingeniously,the generated H_(2)O_(2)provides a source of reactants for the reaction of the Fe_(3)O_(4)nanozyme.In addition,the photothermal effect of Au nanoparticles under 808 nm irradiation further enhanced the nanozyme activity of Fe_(3)O_(4)and Au nanoparticles.Besides,UCNPs can emit near-infrared(NIR)-II fluorescence under 808 nm irradiation,which can provide imaging-guided during cancer treatment.Then,the nanocomposites were further modified by poly(vinylpyrrolidone)(PVP)to obtain UCNPs/Au/Fe_(3)O_(4)-PVP with good biocompatibility and high-efficiency cancer treatment ability.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21773311 and 21972169)Hunan Provincial Science and Technology Plan Project(No.2017TP1001)Thanks for the software support provided by the High Performance Computing Center of CSU and NMR data support provided by the Institute of Chemistry Chinese Academy of Sciences.
文摘Small-molecule hydrogels based on amino acid derivatives have promising applications in many biological fields,including cell culture,drug delivery,and tissue engineering.Although these hydrogels have been widely reported to have low cytotoxicity,biocompatibility,and tunable bioactivity,problems such as harsh preparation conditions and complex material design hinder their application.Herein,by adjusting pH to induce non-covalent interactions between small-molecule tryptophan derivatives(N-[(phenylmethoxy)carbonyl]-L-tryptophan,Mw:338.35),we developed a self-assembled three-dimensional network hydrogel that can be rapidly formed in seconds.And the supramolecular self-assembly mechanism of the hydrogels was also investigated in detail through experimental characterizations and density functional theory calculation.As-prepared hydrogels also exhibit reversible pH-stimulated response and self-healing properties.This study details a research process for the simple and rapid preparation of tryptophan derivative-based hydrogels,which provides more reference ideas for the future development of materials based on other amino acid derivatives.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.52103276,51533009,and 22071271)the Natural Science Foundation of Guangdong Province of China(No.2022A1515010947)+2 种基金Guangzhou Basic and Applied Basic Research Foundation(No.202201011343)the Key Areas Research and Development Program of Guangzhou(202007020006)the Hundred Talents Program Startup Grant of Sun Yat-sen University.
文摘In the past few decades,significant progress in block copolymer self-assembly has been achieved in many fields,and with the development of nanoscience and nanotechnology,more and more complex situations need block copolymer self-assembly based nanoplatforms having more complex structures for specific multimodal or multiplexed applications.Through the combination of emulsification and self-assembly of the block copolymer,different materials with exotic architectures and functions could be combined within an entity,such as controlled vesicles,Janus particles,and composite particles which are more like ideal nanoplatforms.Various designs can show their different desired properties depending upon the application situation,including molecular delivery,surfactants,and multicolor encoding.This review will provide a complete summary of the optimization and the synthesis method for the recently designed emulsion confined block copolymer assemblies,and also the challenges and limitations this method faces,and the potential solutions in this field.
基金the financial support of the National Natural Science Foundation of China(grant nos.22193031,21961142022,21872150,and 22072160).
文摘Photodynamic therapy(PDT)has emerged as an efficient treatment for cancers in recent years.However,PDT is limited by low utilization of photosensitizers and tumor hypoxia.The short lifetime and diffusion radius of singlet oxygen(^(1)O_(2))further decrease the anticancer effect of PDT.Herein,we design and synthesize diameter-controllable photosensitizer nanoparticles(NPs)which can specifically accumulate on the mitochondria of cancer cells and increase the O_(2) concentrations nearby to enhance PDT efficacy.Catalase(CAT)molecules are initially conjugated with rose bengal(RB)via amide bonds and then self-assembled into CAT-RB NPs.The NPs show excellent enzyme activity in catalyzing the decomposition of hydrogen peroxide into O_(2),which makes the yield of 1O21.65-fold higher than that of free RB.The intracellular uptake efficiency of NPs is increased by up to 150 times compared with pure RB.After endocytosis,the NPs mainly located at mitochondria and ^(1)O_(2) can directly destroy mitochondria under irradiation,thereby greatly decreasing the production of adenosine triphosphate and further leading to the apoptosis of cancer cells.Moreover,CAT-RB NPs can accumulate in tumors and show excellent PDT effects in vivo.This work opens a unique path to break through the current limitations of PDT in cancer treatment.