The seriously range-ambiguous clutter is one of the main problems in clutter suppression for hypersonic vehicle-borne forward-looking radar. An approach based on the frequency diverse array (FDA) technique is proposed...The seriously range-ambiguous clutter is one of the main problems in clutter suppression for hypersonic vehicle-borne forward-looking radar. An approach based on the frequency diverse array (FDA) technique is proposed to mitigate the range ambiguous clutter. The frequency increment is designed to distinguish the clutter at ambiguous ranges and suppress the clutter by using a subspace projection algorithm. On the platform with high altitude or limited array antennas, the proposed method performs better for its independence of the elevation degrees-of-freedom (DOF). Finally, simulation results verify the effectiveness of the proposed method.展开更多
Monsoon has an important impact on the development of vegetation that subsequently has significant influence on the evolution of plant consumers.The diversities of forest dwellers or herbivores follow the evolution of...Monsoon has an important impact on the development of vegetation that subsequently has significant influence on the evolution of plant consumers.The diversities of forest dwellers or herbivores follow the evolution of the vegetation,and it is therefore possible to take such diversities as forest or vegetation dynamic proxies.The present work selected 36 Pleistocene faunas of large mammals from monsoon-dominated provinces in China as materials and calculated the diversities of forest dwellers and herbivores with different approaches,as well as the consensus gradient coefficients of all the selected faunas in different flora regionalized subkingdoms.The results show that with the evolution and transitions of the East Asian summer and winter monsoon intensities,the forest vitality decreased while steppe vitality increased gradually in a fluctuated way from the Early Pleistocene to the Late Pleistocene,especially in the provinces north of the Qinling-Huaihe Line.The analyses of such diversities of the faunas can help to determine the forest dynamic proxies.Moreover,the correlation of such proxies to loess-paleosol sequences and marine isotope stages can in turn help to improve the accuracy of dating fauna ages and paleoenvironment reconstruction.展开更多
【Objectives】Si and microbial application could relieve the crop replanting problems(CRPs).We further studied the change of key microorganisms that are related to the beneficial effects,aiming at provide reference fo...【Objectives】Si and microbial application could relieve the crop replanting problems(CRPs).We further studied the change of key microorganisms that are related to the beneficial effects,aiming at provide reference for the manufacture and application of both microbial agents and Si fertilizer in food lily production.【Methods】A field experiment was conducted over a three-year period,from March 2019 to March 2022.The experimental field had been continuously cultivated with lily for 9 years.Three treatments were established:silicon fertilizer(SF),microbial agents(“Special 8^(TM)”,MF),and combined application of silicon fertilizer and microbial agents(SMF).A control group with blank soil(CK)was also included.At seedling stage of Lanzhou lilies in 2020 and 2021,the shoot and bulb dry weight,and the plant height and stem diameter of Lanzhou lilies were investigated for calculation of seedling index.In July 2020,20 plants were selected in each plot,and root zone soils were sampled at a depth of 20 cm,10 cm away from the roots,and then mixed to form a composite sample.The soil available Si and organic matter content were analyzed,and the fungal community structure and some specific microbial groups in soils were determined with high-throughput sequencing of ITS.【Results】All the three treatments significantly enhanced the lily plant growth and the seedling index,compared to CK.Besides,SF and MF treatments increased the relative abundances(RA)and diversity of fungal communities,and altered the community structures.The RA of some specific groups were found to be significantly correlated with the seedling index and/or soil available Si.Of them,the RA of the genera Fusarium,Dactylonectria,Humicola,Stilbella,and the species Humicola_grisea showed a positive correlation,while that of the genera Mortierella,Stilbella,Holtermanniella,and the species Mortierella_fatshederae showed a negative correlation with seedling index.The genera Fusarium,Stilbella,the species Humicola_grisea,and Dactylonectria_estremocensis showed a positive correlation,while the genura Stilbella,and the species Mortierella fatshederae showed a negative correlation with available Si content.In the co-occurence network of top twenty fungal genera and top sixteen bacterial genera(RA>0.2%),Holtermanniella was the only genus that interacted with the bacteria and negatively correlated with bacterial genus Blastococcus.Holtermanniella was also the most densely connected genera,followed by the genus Fusarium,Didymella and Humicola.In addition,the genus Holtermanniella was the key species connecting fungal and bacterial community in soil.Fungal functional prediction revealed that SF,MF and SMF treatments decreased plant pathogens guilds and increased the beneficial guilds Ectomycorrhizal,plant saprophyte,leaf saprophyte,and arbuscular mycorrhizal compared to CK.【Conclusions】Combined application of silicon fertilizer and microbial agents can alleviate continuous replanting problems of Lanzhou lilies through restoring the fungal community diversity,and promoting plant residue depredation,thus reducing soil born disease incidence.The beneficial genus Humicola and its one species H.grisea acts as bioconversion,and the genus Acremonium acts as plant pathogen inhibitor.展开更多
[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in t...[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.展开更多
This paper conducted a systematic survey and zoogeographical region analysis of the family Sphingidae in the Guokui Mountain,Heilongjiang Province.Collections were made from May 2023 to August 2024 using the light-tra...This paper conducted a systematic survey and zoogeographical region analysis of the family Sphingidae in the Guokui Mountain,Heilongjiang Province.Collections were made from May 2023 to August 2024 using the light-trap method.A total of 14 species and 11 subspecies from 18 genera and three subfamilies were recorded.One species(Ambulyx tobii)and two subspecies(Ambulyx japonica koreana and Clanis undulosa undulosa)were new records for Heilongjiang Province.The study showed that the subfamily Smerinthinae had the most species(subspecies),while the subfamily Sphinginae had the fewest.Among the world's zoogeographical region,most species(subspecies)in the Guokui Mountain belonged to the palearctic region,with eight species and seven subspecies were also found in the oriental region.This indicated a close biogeographic connection between the two regions.Among the Chinese zoogeographical regions,the northeastern territory,northern territory and northwestern territory had the most abundant species(subspecies).It was also found that the distribution pattern types of hawkmoths in the Guokui Mountain were diverse,with the'northeastern territory-northern territory-northwestern territory'and'northeastern territory-northern territorynorthwestern territory-western plateau-southwestern territory-central territory-southeastern territory'types having the most species(subspecies).In addition,the Guokui Mountain hawkmoths were mostly distributed interregionally.The distribution patterns that contained the northeastern territory were the most numerous,followed by the northern territory.The rich diversity of the family Sphingidae in the Guokui Mountain was closely related to the unique climate,environment and vegetation types in the area.The results could help to improve the biodiversity database of Heilongjiang Province and researches on hawkmoths.展开更多
The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term o...The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment.展开更多
When performing tasks,unmanned clusters often face a variety of strategy choices.One of the key issues in unmanned cluster tasks is the method through which to design autonomous collaboration and cooperative evolution...When performing tasks,unmanned clusters often face a variety of strategy choices.One of the key issues in unmanned cluster tasks is the method through which to design autonomous collaboration and cooperative evolution mechanisms that allow for unmanned clusters to maximize their overall task effective-ness under the condition of strategic diversity.This paper ana-lyzes these task requirements from three perspectives:the diver-sity of the decision space,information network construction,and the autonomous collaboration mechanism.Then,this paper pro-poses a method for solving the problem of strategy selection diversity under two network structures.Next,this paper presents a Moran-rule-based evolution dynamics model for unmanned cluster strategies and a vision-driven-mechanism-based evolu-tion dynamics model for unmanned cluster strategy in the con-text of strategy selection diversity according to various unmanned cluster application scenarios.Finally,this paper pro-vides a simulation analysis of the effects of relevant parameters such as the payoff factor and cluster size on cooperative evolu-tion in autonomous cluster collaboration for the two types of models.On this basis,this paper presents advice for effectively addressing diverse choices in unmanned cluster tasks,thereby providing decision support for practical applications of unmanned cluster tasks.展开更多
The Myb family of proteins is a group offunctionally diverse transcriptional activatorsfound in both plants and animals that ischaracterized by a conserved DNA bindingdomain of approximately 50 amino acids.Inplants,My...The Myb family of proteins is a group offunctionally diverse transcriptional activatorsfound in both plants and animals that ischaracterized by a conserved DNA bindingdomain of approximately 50 amino acids.Inplants,Myb proteins are involved in control展开更多
Because of the range-angle dependency in random log frequency diverse array(RD-log-FDA) radar, a method for designing beamspace transformation matrix in angle and range based on the receive signal has been proposed.It...Because of the range-angle dependency in random log frequency diverse array(RD-log-FDA) radar, a method for designing beamspace transformation matrix in angle and range based on the receive signal has been proposed.It is demonstrated that the designed beamspace transformation matrix basically meets the requirements of beam gain.However, there are some problems in the transformation matrix designed, such as unstable beam gain and high sidelobe.Hence, we propose an optimization method by adjusting array element spacing and random number in frequency offset to get the optimum beam gain.Therefore, particle swarm optimization(PSO) is used to find the optimal solution.The beam gain comparison before and after the optimization is obtained by simulation, and the results show that the optimized array after beamspace preprocessing has more stable beam gain, lower sidelobe, and higher resolution in parameter estimation.In conclusion, the RD-log-FDA is capable of forming desired beam gain in angle and distance through beamspace preprocessing, and suppressing interference signals in other areas.展开更多
The range and angle information of the frequency diverse array(FDA) cannot be exclusively determined at the output of the array because of the range-angle coupled transmit beampattern. The best decoupling approach is ...The range and angle information of the frequency diverse array(FDA) cannot be exclusively determined at the output of the array because of the range-angle coupled transmit beampattern. The best decoupling approach is to form a dot-shaped beampattern rather than the S-shaped beampattern of the basic FDA.Considering the degradation of the output signal-to-interferenceplus-noise ratio(SINR) caused by the coupled beampattern, we propose a dot-shaped beamforming method based on the analyzed overlapping subarray-based using a logarithmic offset and a subarray-based planar FDA using a logarithmically increasing frequency offset, with elements transmitting at multiple frequencies. Several simulation results demonstrate the effectiveness of the proposed method in transmit energy focusing, sidelobe suppression and array resolution.展开更多
This paper studies the adaptive beamforming algorithm based on the frequency diverse array(FDA)array where the interference is located at the same angle(but different range)with the target.We take the cross subarray-b...This paper studies the adaptive beamforming algorithm based on the frequency diverse array(FDA)array where the interference is located at the same angle(but different range)with the target.We take the cross subarray-based FDA with sinusoidal frequency offset(CSB sin-FDA)as the receiving array instead of the basic FDA.The sampling covariance matrix under insufficient snapshot can be corrected by the automatic diagonal loading method.On the basis of decomposing the mismatched steering vector error into a vertical component and a parallel one,this paper searches the vertical component of the error by the quadratic constraint method.The numerical simulation verifies that the beamformer based on the CSB sin-FDA can effectively hold the mainlobe at the target position when the snapshot is insufficient or the steering vector is mismatched.展开更多
Laser in situ keratomileusis(LASIK)is a relatively new ophthalmic procedure in refractive surgery.It involves the use of a microkeratome to create a thin corneal flap followed by excimer laser ablation of the corneal ...Laser in situ keratomileusis(LASIK)is a relatively new ophthalmic procedure in refractive surgery.It involves the use of a microkeratome to create a thin corneal flap followed by excimer laser ablation of the corneal stroma and repositioning of the flap.However,complications are bound to occur when a surgical procedure is performed with increasing frequency.In some cases,serious complications such as keratectasia occurred.Risk factors for corneal keratectasia include a thin cornea at baseline,thick corneal flap,excessive ablation,irregular corneal thickness,diverse ablation rates,preexisting keratoconus or form fruste keratoconus,and high intraocular pressure(IOP)~[1].It is evident from incisional refractive surgery that the cornea is not mechanically inert.The mechanical environment of the central corneal tissue is also altered un-展开更多
The adaptive immune system produces a large and diverse set of antibodies,each with an individual evolutionary and clonal history.This so called"antibody repertoire"protects each individual against insults s...The adaptive immune system produces a large and diverse set of antibodies,each with an individual evolutionary and clonal history.This so called"antibody repertoire"protects each individual against insults such as infection and cancer,and responds to vaccination with B cell proliferation in response to the antigenic stimulation.Hybridomas and antigen-specific FACSbased analysis have given us much insight on how the immune system generates the complex and diverse immune response required to protect the body from the wide variety of potential pathogens.However,these methods have not been sufficient to make global and unbiased characterizations of the clonal structure of the immune system of a particular individual。展开更多
基于AutoCAD To ANSYS(ADINA)三维建模程序,利用AutoCAD生成ANSYS(ADINA)命令流文件、ANSYS完整建模和网格划分、FLAC计算、采用TECPLOT后处理的建模计算后处理流程,极大提高了数值仿真效率和精度。以大山口二级水电站引水隧洞围岩为例...基于AutoCAD To ANSYS(ADINA)三维建模程序,利用AutoCAD生成ANSYS(ADINA)命令流文件、ANSYS完整建模和网格划分、FLAC计算、采用TECPLOT后处理的建模计算后处理流程,极大提高了数值仿真效率和精度。以大山口二级水电站引水隧洞围岩为例进行围岩稳定性仿真分析,评价引水隧洞开挖后的稳定性,建议重点支护引水隧洞桩号1 200 m左右洞段,可适当加厚衬砌,断层或挤压破碎带与洞室开挖面交汇处施加一定数量的预应力锚索,在洞顶布设一定数量的监测点,并随时跟踪洞室关键点的位移发展情况。展开更多
基金supported by the National Natural Science Foundation of China(61301282)
文摘The seriously range-ambiguous clutter is one of the main problems in clutter suppression for hypersonic vehicle-borne forward-looking radar. An approach based on the frequency diverse array (FDA) technique is proposed to mitigate the range ambiguous clutter. The frequency increment is designed to distinguish the clutter at ambiguous ranges and suppress the clutter by using a subspace projection algorithm. On the platform with high altitude or limited array antennas, the proposed method performs better for its independence of the elevation degrees-of-freedom (DOF). Finally, simulation results verify the effectiveness of the proposed method.
文摘Monsoon has an important impact on the development of vegetation that subsequently has significant influence on the evolution of plant consumers.The diversities of forest dwellers or herbivores follow the evolution of the vegetation,and it is therefore possible to take such diversities as forest or vegetation dynamic proxies.The present work selected 36 Pleistocene faunas of large mammals from monsoon-dominated provinces in China as materials and calculated the diversities of forest dwellers and herbivores with different approaches,as well as the consensus gradient coefficients of all the selected faunas in different flora regionalized subkingdoms.The results show that with the evolution and transitions of the East Asian summer and winter monsoon intensities,the forest vitality decreased while steppe vitality increased gradually in a fluctuated way from the Early Pleistocene to the Late Pleistocene,especially in the provinces north of the Qinling-Huaihe Line.The analyses of such diversities of the faunas can help to determine the forest dynamic proxies.Moreover,the correlation of such proxies to loess-paleosol sequences and marine isotope stages can in turn help to improve the accuracy of dating fauna ages and paleoenvironment reconstruction.
基金Key Research project of Gansu Province of China(22YF7NA108)National Natural Science Foundation of China(31860549)+1 种基金Industry Supporting Project from Education Department of Gansu Province(2023CYZC-49)Major Science and Technology project of Gansu province(24ZDNA006)。
文摘【Objectives】Si and microbial application could relieve the crop replanting problems(CRPs).We further studied the change of key microorganisms that are related to the beneficial effects,aiming at provide reference for the manufacture and application of both microbial agents and Si fertilizer in food lily production.【Methods】A field experiment was conducted over a three-year period,from March 2019 to March 2022.The experimental field had been continuously cultivated with lily for 9 years.Three treatments were established:silicon fertilizer(SF),microbial agents(“Special 8^(TM)”,MF),and combined application of silicon fertilizer and microbial agents(SMF).A control group with blank soil(CK)was also included.At seedling stage of Lanzhou lilies in 2020 and 2021,the shoot and bulb dry weight,and the plant height and stem diameter of Lanzhou lilies were investigated for calculation of seedling index.In July 2020,20 plants were selected in each plot,and root zone soils were sampled at a depth of 20 cm,10 cm away from the roots,and then mixed to form a composite sample.The soil available Si and organic matter content were analyzed,and the fungal community structure and some specific microbial groups in soils were determined with high-throughput sequencing of ITS.【Results】All the three treatments significantly enhanced the lily plant growth and the seedling index,compared to CK.Besides,SF and MF treatments increased the relative abundances(RA)and diversity of fungal communities,and altered the community structures.The RA of some specific groups were found to be significantly correlated with the seedling index and/or soil available Si.Of them,the RA of the genera Fusarium,Dactylonectria,Humicola,Stilbella,and the species Humicola_grisea showed a positive correlation,while that of the genera Mortierella,Stilbella,Holtermanniella,and the species Mortierella_fatshederae showed a negative correlation with seedling index.The genera Fusarium,Stilbella,the species Humicola_grisea,and Dactylonectria_estremocensis showed a positive correlation,while the genura Stilbella,and the species Mortierella fatshederae showed a negative correlation with available Si content.In the co-occurence network of top twenty fungal genera and top sixteen bacterial genera(RA>0.2%),Holtermanniella was the only genus that interacted with the bacteria and negatively correlated with bacterial genus Blastococcus.Holtermanniella was also the most densely connected genera,followed by the genus Fusarium,Didymella and Humicola.In addition,the genus Holtermanniella was the key species connecting fungal and bacterial community in soil.Fungal functional prediction revealed that SF,MF and SMF treatments decreased plant pathogens guilds and increased the beneficial guilds Ectomycorrhizal,plant saprophyte,leaf saprophyte,and arbuscular mycorrhizal compared to CK.【Conclusions】Combined application of silicon fertilizer and microbial agents can alleviate continuous replanting problems of Lanzhou lilies through restoring the fungal community diversity,and promoting plant residue depredation,thus reducing soil born disease incidence.The beneficial genus Humicola and its one species H.grisea acts as bioconversion,and the genus Acremonium acts as plant pathogen inhibitor.
文摘[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.
基金Supported by the Department of Ecology and Environment of Heilongjiang Province(HST2022ST003)。
文摘This paper conducted a systematic survey and zoogeographical region analysis of the family Sphingidae in the Guokui Mountain,Heilongjiang Province.Collections were made from May 2023 to August 2024 using the light-trap method.A total of 14 species and 11 subspecies from 18 genera and three subfamilies were recorded.One species(Ambulyx tobii)and two subspecies(Ambulyx japonica koreana and Clanis undulosa undulosa)were new records for Heilongjiang Province.The study showed that the subfamily Smerinthinae had the most species(subspecies),while the subfamily Sphinginae had the fewest.Among the world's zoogeographical region,most species(subspecies)in the Guokui Mountain belonged to the palearctic region,with eight species and seven subspecies were also found in the oriental region.This indicated a close biogeographic connection between the two regions.Among the Chinese zoogeographical regions,the northeastern territory,northern territory and northwestern territory had the most abundant species(subspecies).It was also found that the distribution pattern types of hawkmoths in the Guokui Mountain were diverse,with the'northeastern territory-northern territory-northwestern territory'and'northeastern territory-northern territorynorthwestern territory-western plateau-southwestern territory-central territory-southeastern territory'types having the most species(subspecies).In addition,the Guokui Mountain hawkmoths were mostly distributed interregionally.The distribution patterns that contained the northeastern territory were the most numerous,followed by the northern territory.The rich diversity of the family Sphingidae in the Guokui Mountain was closely related to the unique climate,environment and vegetation types in the area.The results could help to improve the biodiversity database of Heilongjiang Province and researches on hawkmoths.
文摘The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment.
基金supported by the National Natural Science Foundation of China(72471240).
文摘When performing tasks,unmanned clusters often face a variety of strategy choices.One of the key issues in unmanned cluster tasks is the method through which to design autonomous collaboration and cooperative evolution mechanisms that allow for unmanned clusters to maximize their overall task effective-ness under the condition of strategic diversity.This paper ana-lyzes these task requirements from three perspectives:the diver-sity of the decision space,information network construction,and the autonomous collaboration mechanism.Then,this paper pro-poses a method for solving the problem of strategy selection diversity under two network structures.Next,this paper presents a Moran-rule-based evolution dynamics model for unmanned cluster strategies and a vision-driven-mechanism-based evolu-tion dynamics model for unmanned cluster strategy in the con-text of strategy selection diversity according to various unmanned cluster application scenarios.Finally,this paper pro-vides a simulation analysis of the effects of relevant parameters such as the payoff factor and cluster size on cooperative evolu-tion in autonomous cluster collaboration for the two types of models.On this basis,this paper presents advice for effectively addressing diverse choices in unmanned cluster tasks,thereby providing decision support for practical applications of unmanned cluster tasks.
文摘The Myb family of proteins is a group offunctionally diverse transcriptional activatorsfound in both plants and animals that ischaracterized by a conserved DNA bindingdomain of approximately 50 amino acids.Inplants,Myb proteins are involved in control
基金supported by the National Natural Science Foundation of China (62001506)。
文摘Because of the range-angle dependency in random log frequency diverse array(RD-log-FDA) radar, a method for designing beamspace transformation matrix in angle and range based on the receive signal has been proposed.It is demonstrated that the designed beamspace transformation matrix basically meets the requirements of beam gain.However, there are some problems in the transformation matrix designed, such as unstable beam gain and high sidelobe.Hence, we propose an optimization method by adjusting array element spacing and random number in frequency offset to get the optimum beam gain.Therefore, particle swarm optimization(PSO) is used to find the optimal solution.The beam gain comparison before and after the optimization is obtained by simulation, and the results show that the optimized array after beamspace preprocessing has more stable beam gain, lower sidelobe, and higher resolution in parameter estimation.In conclusion, the RD-log-FDA is capable of forming desired beam gain in angle and distance through beamspace preprocessing, and suppressing interference signals in other areas.
基金supported by the National Natural Science Foundation of China(61503408)。
文摘The range and angle information of the frequency diverse array(FDA) cannot be exclusively determined at the output of the array because of the range-angle coupled transmit beampattern. The best decoupling approach is to form a dot-shaped beampattern rather than the S-shaped beampattern of the basic FDA.Considering the degradation of the output signal-to-interferenceplus-noise ratio(SINR) caused by the coupled beampattern, we propose a dot-shaped beamforming method based on the analyzed overlapping subarray-based using a logarithmic offset and a subarray-based planar FDA using a logarithmically increasing frequency offset, with elements transmitting at multiple frequencies. Several simulation results demonstrate the effectiveness of the proposed method in transmit energy focusing, sidelobe suppression and array resolution.
基金supported by the National Natural Science Foundation of China(61503408)
文摘This paper studies the adaptive beamforming algorithm based on the frequency diverse array(FDA)array where the interference is located at the same angle(but different range)with the target.We take the cross subarray-based FDA with sinusoidal frequency offset(CSB sin-FDA)as the receiving array instead of the basic FDA.The sampling covariance matrix under insufficient snapshot can be corrected by the automatic diagonal loading method.On the basis of decomposing the mismatched steering vector error into a vertical component and a parallel one,this paper searches the vertical component of the error by the quadratic constraint method.The numerical simulation verifies that the beamformer based on the CSB sin-FDA can effectively hold the mainlobe at the target position when the snapshot is insufficient or the steering vector is mismatched.
基金supported by the National Natural Science Foundation of China(11032008)Natural Science Foundation of Shanxi Province(2012011046-2)
文摘Laser in situ keratomileusis(LASIK)is a relatively new ophthalmic procedure in refractive surgery.It involves the use of a microkeratome to create a thin corneal flap followed by excimer laser ablation of the corneal stroma and repositioning of the flap.However,complications are bound to occur when a surgical procedure is performed with increasing frequency.In some cases,serious complications such as keratectasia occurred.Risk factors for corneal keratectasia include a thin cornea at baseline,thick corneal flap,excessive ablation,irregular corneal thickness,diverse ablation rates,preexisting keratoconus or form fruste keratoconus,and high intraocular pressure(IOP)~[1].It is evident from incisional refractive surgery that the cornea is not mechanically inert.The mechanical environment of the central corneal tissue is also altered un-
基金supported by the National Institutes of Health grant U19 A1057229(M.M. D.,X.H.,H.B.G.and S.R.Q.)a National Institutes of Health Pathway to Independence Award K99 AG040149(N.J.)a National Science Foundation graduate fellowship(J.A.W.)
文摘The adaptive immune system produces a large and diverse set of antibodies,each with an individual evolutionary and clonal history.This so called"antibody repertoire"protects each individual against insults such as infection and cancer,and responds to vaccination with B cell proliferation in response to the antigenic stimulation.Hybridomas and antigen-specific FACSbased analysis have given us much insight on how the immune system generates the complex and diverse immune response required to protect the body from the wide variety of potential pathogens.However,these methods have not been sufficient to make global and unbiased characterizations of the clonal structure of the immune system of a particular individual。
文摘基于AutoCAD To ANSYS(ADINA)三维建模程序,利用AutoCAD生成ANSYS(ADINA)命令流文件、ANSYS完整建模和网格划分、FLAC计算、采用TECPLOT后处理的建模计算后处理流程,极大提高了数值仿真效率和精度。以大山口二级水电站引水隧洞围岩为例进行围岩稳定性仿真分析,评价引水隧洞开挖后的稳定性,建议重点支护引水隧洞桩号1 200 m左右洞段,可适当加厚衬砌,断层或挤压破碎带与洞室开挖面交汇处施加一定数量的预应力锚索,在洞顶布设一定数量的监测点,并随时跟踪洞室关键点的位移发展情况。
