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Numerical Simulation of the Settling Flux of Biodeposition in a Bay with Cage Culture Through Similarity Theory and a Simplified Pollution Source
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作者 LIU Yao CHEN Yifan GE Changzi 《Journal of Ocean University of China》 CAS CSCD 2024年第1期247-254,共8页
The settling flux of biodeposition affects the environmental quality of cage culture areas and determines their environmental carrying capacity.Simple and effective simulation of the settling flux of biodeposition is ... The settling flux of biodeposition affects the environmental quality of cage culture areas and determines their environmental carrying capacity.Simple and effective simulation of the settling flux of biodeposition is extremely important for determining the spatial distribution of biodeposition.Theoretically,biodeposition in cage culture areas without specific emission rules can be simplified as point source pollution.Fluent is a fluid simulation software that can simulate the dispersion of particulate matter simply and efficiently.Based on the simplification of pollution sources and bays,the settling flux of biodeposition can be easily and effectively simulated by Fluent fluid software.In the present work,the feasibility of this method was evaluated by simulation of the settling flux of biodeposition in Maniao Bay,Hainan Province,China,and 20 sampling sites were selected for determining the settling fluxes.At sampling sites P1,P2,P3,P4,P5,Z1,Z2,Z3,Z4,A1,A2,A3,A4,B1,B2,C1,C2,C3 and C4,the measured settling fluxes of biodeposition were 26.02,15.78,10.77,58.16,6.57,72.17,12.37,12.11,106.64,150.96,22.59,11.41,18.03,7.90,19.23,7.06,11.84,5.19 and 2.57 g d^(−1)m^(−2),respectively.The simulated settling fluxes of biodeposition at the corresponding sites were 16.03,23.98,8.87,46.90,4.52,104.77,16.03,8.35,180.83,213.06,39.10,17.47,20.98,9.78,23.25,7.84,15.90,6.06 and 1.65 g d^(−1)m^(−2),respectively.There was a positive correlation between the simulated settling fluxes and measured ones(R=0.94,P=2.22×10^(−9)<0.05),which implies that the spatial differentiation of biodeposition flux was well simulated.Moreover,the posterior difference ratio of the simulation was 0.38,and the small error probability was 0.94,which means that the simulated results reached an acceptable level from the perspective of relative error.Thus,if nonpoint source pollution is simplified to point source pollution and open waters are simplified based on similarity theory,the setting flux of biodeposition in the open waters can be simply and effectively simulated by the fluid simulation software Fluent. 展开更多
关键词 fluent fluid simulation software pollution source simplification posterior difference ratio similarity theory Spear-man correlation
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Growth and Diet Utilization Efficiencies of Overwinter Juvenile Mud Crabs Fed with Different Diets
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作者 Shengping ZHONG Yan JIANG +6 位作者 Changzi GE Xiaohui CAI Jianda SONG Yonghong LIU Lianghua HUANG Yinhui PENG Guoqiang HUANG 《Asian Agricultural Research》 2024年第11期36-43,共8页
[Objectives]To study the utilization efficiency of different diets for juvenile Scylla paramamosain.[Methods]Low-value fish,shrimp,clam and clamworm were fed to overwintering young mud crabs,and the performance of the... [Objectives]To study the utilization efficiency of different diets for juvenile Scylla paramamosain.[Methods]Low-value fish,shrimp,clam and clamworm were fed to overwintering young mud crabs,and the performance of the feed was evaluated by growth,feed utilization and energy allocation.[Results]Shrimp-fed mud crabs showed the best growth performance,while fish-fed mud crabs showed the worst growth performance and converted the least protein and energy for growth.Shrimp-fed mud crabs molted more frequently,and the dry matter mass and energy of Exuviation were significantly higher than those of fish-fed mud crabs.The shrimp-fed crabs also had significantly higher food intake than those fish-fed crabs.The order of feed conversion efficiency(FCE)of fish-fed mud crabs was Polychaete>clam>shrimp>fish,while the order of FCE calculated with FCE-P and FCE-E was Polychaete>clam>shrimp>fish.Fish-fed mud crabs had the least energy intake and the least energy for growth,molting,excretion,metabolism,and feces.Among the four treatments,the mud crabs fed on Polychaete had the largest proportion of energy used for growth,while the mud crabs fed on fish had the largest proportion of energy used for molting.The proportion of energy consumed by mud crabs fed on Polychaete was the smallest,which may be the main reason for the higher FCE-P and FCE-E of mud crabs fed on Polychaete.[Conclusions]The results of this experiment showed that the utilization of low-value fish by mud crabs was the worst,suggesting that fish should not be used as control or reference food when studying the formula feed of mud crabs. 展开更多
关键词 Mud crab(Scylla paramamosain) Natural feed GROWTH Feed conversion efficiency(FCE) Energy allocation
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An Efficient and Lightweight YOLOv8s Strawberry Maturity Detection Model
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作者 Yiming Cheng Guohao Feng Chunchang Zhang 《Journal of Agricultural Science and Technology(A)》 2024年第2期46-66,共21页
The manual picking of strawberries is inefficient and costly,limiting scalability and economic benefits.Mechanizing this process reduces labor demands,improves working conditions,and modernizes the strawberry industry... The manual picking of strawberries is inefficient and costly,limiting scalability and economic benefits.Mechanizing this process reduces labor demands,improves working conditions,and modernizes the strawberry industry.Target detection technology,crucial for mechanized picking,must accurately determine strawberry maturity.This study presents an enhanced YOLOv8s model addressing current machine learning issues like accuracy,parameters,and complexity.The improved model replaces the Bottleneck structure in C2f with the FasterNet network,integrates an efficient multi-scale attention mechanism,and uses the Ghost module in the backbone to reduce computational load while maintaining performance.It also introduces Wise-IoU for bounding box regression loss,improving recognition accuracy.The YOLOv8s-FEGW model achieves a 93.8%mAP in detecting strawberry ripeness,with significant reductions in parameters(36.8%),complexity(34.6%),and model size(37.7%),alongside a 12.7% Frames Per Second(FPS)boost.These enhancements result in excellent detection capabilities,supporting agricultural automation and intelligence. 展开更多
关键词 Automation equipment artificial intelligence efficient and lightweight YOLOv8s
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Furnace Temperature Curve Optimization Model Based on Differential Evolution Algorithm
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作者 Yiming Cheng 《Journal of Electronic Research and Application》 2024年第4期64-80,共17页
When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on ... When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on optimizing the furnace temperature curve under varying settings of reflow oven zone temperatures and conveyor belt speeds.To address this,the research sequentially develops a heat transfer model for reflow soldering,an optimization model for reflow furnace conditions using the differential evolution algorithm,and an evaluation and decision model combining the differential evolution algorithm with the Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)method.This approach aims to determine the optimal furnace temperature curve,zone temperatures of the reflow oven,and the conveyor belt speed. 展开更多
关键词 Furnace temperature curve Difference equations Differential evolution algorithms TOPSIS methods
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Steady State Analysis of Towed Marine Cables 被引量:8
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作者 王飞 黄国樑 邓德衡 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第2期239-244,共6页
Efficient numerical schemes were presented for the steady state solutions of towed marine cables. For most of towed systems,the steady state problem can be resolved into two-point boundary-value problem,or initial val... Efficient numerical schemes were presented for the steady state solutions of towed marine cables. For most of towed systems,the steady state problem can be resolved into two-point boundary-value problem,or initial value problem in some special cases where the initial values are available directly.A new technique was proposed and attempted to solve the two-point boundary-value problem rather than the conventional shooting method due to its algorithm complexity and low efficiency.First,the boundary conditions are transformed into a set of nonlinear governing equations about the initial values,then bisection method is employed to solve these nonlinear equations with the aid of 4th order Runge-Kutta method.In common sense,non-uniform (sheared) current is assumed,which varies in magnitude and direction with depth.The schemes are validated through the DE Zoysa's example,then several numerical examples are also presented to illustrate the numerical schemes. 展开更多
关键词 towed cable nested bisection method Runge-Kutta method non-uniform current numerical simulation
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Research Review on Marine Search and Rescue 被引量:2
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作者 CHEN Xinqiang SHI Chaojian +3 位作者 WANG Shengzheng WU Huafeng XU Tie KE Ruimin 《Journal of Shipping and Ocean Engineering》 2017年第3期112-120,共9页
Locating the marine target in a quick and precise way is the crucial point of implementing SAR (search and rescue) at sea, which involves aspects of developing SAR strategy and detects the marine targets. As the eff... Locating the marine target in a quick and precise way is the crucial point of implementing SAR (search and rescue) at sea, which involves aspects of developing SAR strategy and detects the marine targets. As the effect of marine target detection restricts the SAR result directly, the study has focused on reviewing the previous research about marine target detection, especially dim marine target detection. What's more, small target detection under complex sea status is one of the severe challenges which is research's hotspot and needs more endeavor. Current research results and future research directions are discussed in the paper. The findings can provide systematic view of implementing maritime search and rescue for field researchers and governors. 展开更多
关键词 Maritime accident search and rescue complex marine condition dim target detection smart ship.
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Novel Energy-Efficient Opportunistic Routing Protocol for Marine Wireless Sensor Networks Based on Compressed Sensing and Power Control
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作者 XIAN Jiangfeng WU Huafeng +4 位作者 MEI Xiaojun ZHANG Yuanyuan CHEN Xinqiang ZHANG Qiannan LIANG Linian 《Journal of Ocean University of China》 SCIE CAS CSCD 2022年第6期1504-1516,共13页
In marine wireless sensor networks(MWSNs),an appropriate routing protocol is the key to the collaborative collection and efficient transmission of massive data.However,designing an appropriate routing protocol under t... In marine wireless sensor networks(MWSNs),an appropriate routing protocol is the key to the collaborative collection and efficient transmission of massive data.However,designing an appropriate routing protocol under the condition of sparse marine node deployment,highly dynamic network topology,and limited node energy is complicated.Moreover,the absence of continuous endto-end connection introduces further difficulties in the design of routing protocols.In this case,we present a novel energy-efficient opportunistic routing(Novel Energy-Efficient Opportunistic Routing,NEOR)protocol for MWSNs that is based on compressed sensing and power control.First,a lightweight time-series prediction method-weighted moving average method is proposed to predict the packet advancement value such that the number of location information that is exchanged among a node and its neighbor nodes can be minimized.Second,an adaptive power control mechanism is presented to determine the optimal transmitting power and candidate nodeset on the basis of node mobility,packet advancement,communication link quality,and remaining node energy.Subsequently,a timer-based scheduling algorithm is utilized to coordinate packet forwarding to avoid packet conflict.Furthermore,we introduce the compressed sensing theory to compress perceptual data at source nodes and reconstruct the original data at sink nodes.Therefore,energy consumption in the MWSNs is greatly reduced due to the decrease in the amount of data perception and transmission.Numerical simulation experiments are carried out in a wide range of marine scenarios to verify the superiority of our approach over selected benchmark algorithms. 展开更多
关键词 marine wireless sensor networks opportunistic routing weighted moving average adaptive power control compressed sensing
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Compulsory Liability Insurance for Marine Drilling Platforms Pollution under Chinese Law
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作者 XU Tie ZHANG Pengfei 《Journal of Shipping and Ocean Engineering》 2016年第6期356-363,共8页
Compulsory liability insurance has widely existed in the field of marine insurance. However, marine drilling platforms have always been excluded from this system in China. In view of the special legal nature of oil po... Compulsory liability insurance has widely existed in the field of marine insurance. However, marine drilling platforms have always been excluded from this system in China. In view of the special legal nature of oil pollution compulsory liability insurance for marine drilling platforms, this paper analyzes a number of issues related to oil pollution compulsory liability insurance, elaborates on the necessity for China to implement the system and makes some suggestions about the implementation of that. 展开更多
关键词 Marine drilling platforms oil pollution compulsory liability insurance.
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Transfer Learning-Based Image Recognition of Nitrogen and Potassium Nutrient Stress in Rice 被引量:1
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作者 CHEN Lisu LI Wei +2 位作者 FENG Daolun WU Huafeng WANG Ke 《Rice science》 SCIE CSCD 2023年第2期100-103,I0014-I0019,共10页
Nitrogen(N) and potassium(K) are essential elements for rice growth. When N and K are in deficient rice, specific symptoms appear on the leaves that are similar and difficult to distinguish with the naked eye.
关键词 NUTRIENT POTASSIUM POTASSIUM
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生物柴油在船用低速机上的燃烧分析研究
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作者 魏存锋 江国和 +2 位作者 崔磊 吴刚 钟莎莎 《哈尔滨工程大学学报(英文版)》 CSCD 2023年第4期861-869,共9页
To study the applicability of biodiesel in marine engines,this research investigated the performance,combustion characteristics,and emission characteristics of biodiesel(B100),diesel,and a 50%volume blend of the two f... To study the applicability of biodiesel in marine engines,this research investigated the performance,combustion characteristics,and emission characteristics of biodiesel(B100),diesel,and a 50%volume blend of the two fuels(B50)in a marine engine.This study was conducted on a 4-cylinder,520 mm-bore,two-stroke,low-speed marine engine with a common rail fuel and exhaust gas charge system.The three fuels were tested at different loads from 25%–100%with a step size of 25%.Results showed that the fuel consumption of pure biodiesel increased by about 13.5%and 3.8%relative to that of diesel at 25%and 100%loads,respectively,and by about 6%at 50%and 75%loads.In-cylinder combustion pressure was slightly reduced when the engine ran on biofuel,and black carbon emissions from biodiesel were reduced by an average of 54.7%.Compared with those from diesel,the carbon CO and total hydrocarbon emissions from B100 were reduced by 11.3%and 39%,respectively.Nitroxide emissions were elevated for B100 and B50 under all loading conditions.The properties of B50 blended diesel lie between those of B100 and diesel.In terms of combustion characteristics and emissions,biodiesel can be used without changing the engine parameters and can effectively reduce pollution,such as black carbon and carbon monoxide. 展开更多
关键词 Low-speed engines EMISSIONS BIODIESEL Black carbon Low-carbon fuels
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载人潜水器支持母船水下辐射噪声评估和试验分析研究
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作者 邹祥依 江国和 叶林昌 《哈尔滨工程大学学报(英文版)》 CSCD 2023年第2期334-343,共10页
This study investigates the underwater radiated noise(URN)of a manned submersible support mother ship.To this end,a detailed finite element model of the hull and outflow field is established,and the vibration wet mode... This study investigates the underwater radiated noise(URN)of a manned submersible support mother ship.To this end,a detailed finite element model of the hull and outflow field is established,and the vibration wet mode of the scientific research ship is calculated.A combination of finite element and boundary element methods is used to analyze the spectral features of ship low-frequency URN.The URN source is comprehensively analyzed,the vibration energy is considered the basic parameter to describe the vibration,and the medium-and high-frequency URN of the ship are calculated using the statistical energy analysis.To obtain the full frequency-band URN of the ship,the risk position of exceeding the standard is determined,and the contribution of each main noise source in the ship to the URN is analyzed.The URN level of the ship is comprehensively measured in the free navigation state.The accuracy of the URN control evaluation model,and the method of the ship are verified.The data support for the ship to apply for the classification society certificate provides a scheme reference for the URN control of other scientific research ship in the future. 展开更多
关键词 Scientific research ship Manned submersible Mother ship Underwater radiated noise Noise source Experimental measurement
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Subducting passive continental margins with crustal (ultra)mafic intrusions: An underappreciated mechanism for recycling water back into the mantle
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作者 CaiCai Pan XiaoBo He 《Earth and Planetary Physics》 CAS CSCD 2023年第5期576-581,共6页
It is well known that outer rise bending-assisted oceanic plate hydration is an important mechanism for transporting substantial amounts of water into the mantle.A key question is:Are there other equally or more impor... It is well known that outer rise bending-assisted oceanic plate hydration is an important mechanism for transporting substantial amounts of water into the mantle.A key question is:Are there other equally or more important water transport mechanisms?Here we propose,for the first time,that subducting passive continental margins,particularly those with crustal(ultra)mafic intrusions,play a critical role in recycling water back into the mantle.Evidence for this mechanism is the exceptionally high outer rise seismicity observed in a subducting passive continental margin(i.e.,the northeastern South China Sea continental margin)near the northern Manila trench,characterized by a high-velocity lower crust that has been attributed to(ultra)mafic intrusions.Our interpretation of this correlation between high outer rise seismicity and lower crust(ultra)mafic intrusions is that(ultra)mafic intrusions alter the crustal rheology and increase brittle deformation in the lower crust in this region,thereby promoting lithospheric fracturing and plate hydration,which is evidenced by increased outer rise seismicity. 展开更多
关键词 (ultra)mafic intrusion passive margin lithospheric fracturing outer rise plate hydration
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Simulation of anchor chain based on lumped mass method
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作者 Xiaobin Jiang Jian Gan Shiyang Teng 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2023年第4期311-319,共9页
In order to develop a anchoring operation simulation system and improve safety during anchoring operations,a relatively accurate mathematical model of anchoring operations needs to be established.In this paper,the str... In order to develop a anchoring operation simulation system and improve safety during anchoring operations,a relatively accurate mathematical model of anchoring operations needs to be established.In this paper,the stress condition of anchor chain under environmental and subsea geological conditions is further studied and the stress condition of anchor chain is analyzed based on the previous research.In this paper,a quasi-static model based on catenary method is used as the basis of dynamic analysis,and the dynamic model of anchor chain is established based on the concentrated mass method,which fully considers the influence of anchor chain weight,hydrodynamic force,ocean current and interaction with the seabed.The fourth-order Runge Kutta method was used to solve the model numerically,and a calculation procedure was developed.The accuracy of the model was verified by comparing the calculated results with the experimental results,indicating that the constructed anchor chain dynamics model has a high accuracy. 展开更多
关键词 Lump mass method Anchor chain Dynamic analysis
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Progressive Failure Analysis of Composite/Aluminum Riveted Joints Subjected to Pull-Through Loading
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作者 Yuxing Yang Yongjie Bao +2 位作者 Xueshu Liu Jinlong Wang Fengming Du 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第1期129-138,共10页
Out-of-plane mechanical properties of the riveted joints restrict the performance of the wing box assembly of airplane.It is necessary to investigate the pull-through performance of the composite/metal riveted joints ... Out-of-plane mechanical properties of the riveted joints restrict the performance of the wing box assembly of airplane.It is necessary to investigate the pull-through performance of the composite/metal riveted joints in order to guide the riveting design and ensure the safety of the wing box assembly.The progressive failure mechanism of composite/aluminum riveted joint subjected to pull-through loading was investigated by experiments and finite element method.A progressive damage model based on the Hashin-type criteria and zero-thickness cohesive zone method was developed by VUMAT subroutine,which was validated by both open-hole tensile test and three-point bending test.Predicted load-displacement response,failure modes and damage propagation were analysed and compared with the results of the pull-through tests.There are 4 obvious characteristic stages on the load-displacement curve of the pull-through test and that of the finite element model:first load take-up stage,damage stage,second load take-up stage and failure stage.Relative error of stiffness,first load peak and second load peak between finite element method and experiments were 8.1%,-3.3%and 10.6%,respectively.It was found that the specimen was mainly broken by rivet-penetration fracture and delamination of plies of the composite laminate.And the material within the scope of the rivet head is more dangerous with more serious tensile damages than other regions,especially for 90°plies.This study proposes a numerical method for damage prediction and reveals the progressive failure mechanism of the hybrid material riveted joints subjected to the pull-through loading. 展开更多
关键词 Composite/metal joints Riveted joints Pull-through test Progressive damage model
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Report and Phylogeny of a Novel Euplotes Species from China:E.mazeii n.sp.,and Review of E.balteatus(Alveolata,Ciliophora)
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作者 LIAN Chunyu JIANG Jiamei +6 位作者 XI Muchen DONG Jingyi MA Honggang AL-FARRAJ Saleh A STOECK Thorsten WANG Chundi SHAO Chen 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第3期831-841,共11页
The freshwater species,Euplotes mazeii n.sp.,and the marine species,E.balteatus(Dujardin,1841)Diesing,1850 were collected from China and investigated based on their living morphology,ciliary pattern,and small subunit ... The freshwater species,Euplotes mazeii n.sp.,and the marine species,E.balteatus(Dujardin,1841)Diesing,1850 were collected from China and investigated based on their living morphology,ciliary pattern,and small subunit ribosomal RNA(SSU rRNA)gene sequence data.Euplotes mazeii n.sp.was characterized by its small cell size((40-55)μm×(25-35)μm),nine frontoventral cirri,one marginal and two caudal cirri,seven dorsal kineties,and a double-eurystomus type of dorsal silverline system.Phylogenetic analyses based on molecular data confirmed the branching position of this new taxa within the genus Euplotes,with 5.01%(84 nucleotides)sequence variation,supporting the identification of a new species.We re-examined all described and supposedly conspecific populations and give a review of Euplotes balteatus.E.balteatus has been reported frequently;however,E.balteatus sensu Agamaliev,1968 is different from other populations in the number of marginal cirri or the type of silverline system,which suggests there might be a misidentification.The SSU rRNA gene sequences of two populations of E.balteatus from the studies of Chen et al.(2013)and Pan et al.(2012)differ from each other by more than 135 nucleotides,implying that the identity of the species currently associated with the SSU rRNA gene sequence in molecular databases requires further confirmation. 展开更多
关键词 BIODIVERSITY molecular analysis morphology systematic placement
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Comparative genomics of widespread and narrow-range white-bellied rats in the Niviventer niviventer species complex sheds light on invasive rodent success
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作者 Xin-Lai Wu Dan-Ping Mu +10 位作者 Qi-Sen Yang Yu Zhang Yu-Chun Li Anderson Feijó Ji-Long Cheng Zhi-Xin Wen Liang Lu Lin Xia Zhi-Jun Zhou Yan-Hua Qu De-Yan Ge 《Zoological Research》 SCIE CSCD 2023年第6期1052-1063,共12页
Widespread species that inhabit diverse environments possess large population sizes and exhibit a high capacity for environmental adaptation,thus enabling range expansion.In contrast,narrow-range species are confined ... Widespread species that inhabit diverse environments possess large population sizes and exhibit a high capacity for environmental adaptation,thus enabling range expansion.In contrast,narrow-range species are confined to restricted geographical areas and are ecologically adapted to narrow environmental conditions,thus limiting their ability to expand into novel environments.However,the genomic mechanisms underlying the differentiation between closely related species with varying distribution ranges remain poorly understood.The Niviventer niviventer species complex(NNSC),consisting of highly abundant wild rats in Southeast Asia and China,offers an excellent opportunity to investigate these questions due to the presence of both widespread and narrow-range species that are phylogenetically closely related.In the present study,we combined ecological niche modeling with phylogenetic analysis,which suggested that sister species cannot be both widespread and dominant within the same geographical region.Moreover,by assessing heterozygosity,linkage disequilibrium decay,and Tajima's D analysis,we found that widespread species exhibited higher genetic diversity than narrow-range species.In addition,by exploring the“genomic islands of speciation”,we identified 13 genes in highly divergent regions that were shared by the two widespread species,distinguishing them from their narrow-range counterparts.Functional annotation analysis indicated that these genes are involved in nervous system development and regulation.The adaptive evolution of these genes likely played an important role in the speciation of these widespread species. 展开更多
关键词 Niviventer niviventer species complex Widespread species Narrow-range species Speciation Genomic islands of differentiation PHYLOGENOMICS
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Fault diagnosis of a marine power-generation diesel engine based on the Gramian angular field and a convolutional neural network
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作者 Congyue LI Yihuai HU +1 位作者 Jiawei JIANG Dexin CUI 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2024年第6期470-482,共13页
Marine power-generation diesel engines operate in harsh environments.Their vibration signals are highly complex and the feature information exhibits a non-linear distribution.It is difficult to extract effective featu... Marine power-generation diesel engines operate in harsh environments.Their vibration signals are highly complex and the feature information exhibits a non-linear distribution.It is difficult to extract effective feature information from the network model,resulting in low fault-diagnosis accuracy.To address this problem,we propose a fault-diagnosis method that combines the Gramian angular field(GAF)with a convolutional neural network(CNN).Firstly,the vibration signals are transformed into 2D images by taking advantage of the GAF,which preserves the temporal correlation.The raw signals can be mapped to 2D image features such as texture and color.To integrate the feature information,the images of the Gramian angular summation field(GASF)and Gramian angular difference field(GADF)are fused by the weighted average fusion method.Secondly,the channel attention mechanism and temporal attention mechanism are introduced in the CNN model to optimize the CNN learning mechanism.Introducing the concept of residuals in the attention mechanism improves the feasibility of optimization.Finally,the weighted average fused images are fed into the CNN for feature extraction and fault diagnosis.The validity of the proposed method is verified by experiments with abnormal valve clearance.The average diagnostic accuracy is 98.40%.When−20 dB≤signal-to-noise ratio(SNR)≤20 dB,the diagnostic accuracy of the proposed method is higher than 94.00%.The proposed method has superior diagnostic performance.Moreover,it has a certain anti-noise capability and variable-load adaptive capability. 展开更多
关键词 Multi-attention mechanisms(MAM) Convolutional neural network(CNN) Gramian angular field(GAF) Image fusion Marine power-generation diesel engine Fault diagnosis
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Cultivating the uncultured:Harnessing the“sandwich agar plate”approach to isolate heme-dependent bacteria from marine sediment
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作者 Jing Zhang Qi-Yun Liang +6 位作者 Da-Shuai Mu Fengbai Lian Ya Gong Mengqi Ye Guan-Jun Chen Yuqi Ye Zong-Jun Du 《mLife》 CSCD 2024年第1期143-155,共13页
In the classical microbial isolation technique,the isolation process inevitably destroys all microbial interactions and thus makes it difficult to culture the many microorganisms that rely on these interactions for su... In the classical microbial isolation technique,the isolation process inevitably destroys all microbial interactions and thus makes it difficult to culture the many microorganisms that rely on these interactions for survival.In this study,we designed a simple coculture technique named the“sandwich agar plate method,”which maintains microbial interactions throughout the isolation and pure culture processes.The total yield of uncultured species in sandwich agar plates based on eight helper strains was almost 10-fold that of the control group.Many uncultured species displayed commensal lifestyles.Further study found that heme was the growth-promoting factor of some marine commensal bacteria.Subsequent genomic analysis revealed that heme auxotrophies were common in various biotopes and prevalent in many uncultured microbial taxa.Moreover,our study supported that the survival strategies of heme auxotrophy in different habitats varied considerably.These findings highlight that cocultivation based on the“sandwich agar plate method”could be developed and used to isolate more uncultured bacteria. 展开更多
关键词 CULTIVATION growth factors HEME sandwich agar plate uncultured bacteria
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Particle image velocimetry and numerical simulations of the hydrodynamic characteristics of an artificial reef 被引量:14
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作者 姜昭阳 梁振林 +2 位作者 刘扬 唐衍力 黄六一 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第5期949-956,共8页
This article reports a particle image velocimetry study and the comparative results of a numerical simulation into the hydrodynamic characteristics around an artificial reef.We reveal the process of flow separation an... This article reports a particle image velocimetry study and the comparative results of a numerical simulation into the hydrodynamic characteristics around an artificial reef.We reveal the process of flow separation and vortex evolution,and compare the force terms generated by our artificial reef model.The numerical simulation agrees well with experimental results,showing the applicability of computational fluid dynamics to the hydrodynamics of an artificial reef.Furthermore,we numerically simulate the hydrodynamics of the reef model for seven velocities.The results show that the drag coefficient is approximately 1.21 in a self-modeling region for Reynolds numbers between 2.123×104and 9×104.Therefore,the upwelling height and current width of the flow field do not change significantly when the inflow velocity increases.Our study indicates that computational fluid dynamics can be applied to study the hydrodynamics of an artificial reef and offer clues to its construction. 展开更多
关键词 artificial reef model particle image velocimetry (PIV) flow field hydrodynamic force self-modeling region
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