This work’s goal was to compile a list of fishing-related violations in order to suggest ways to enhance the surveillance system.In order to accomplish this goal,the following approach was used:Executive consultation...This work’s goal was to compile a list of fishing-related violations in order to suggest ways to enhance the surveillance system.In order to accomplish this goal,the following approach was used:Executive consultation and archive exploitation;surveillance agent survey;surveillance system identification and description;identification of offenses and fleet involved in the Guinean exclusive and economic area in recent years;identification and categorization of offense causes;surveillance system evaluation;and suggestion for enhanced surveillance system measures.Monitoring of this strategy showed that:fishing operating zones,administrative paperwork,and fishing gear are all linked to the infractions committed in the Guinean exclusive and economic zone.Records show that there were 308 boardings between 2006 and 2021.IP(Intellectual Property)infringement rates are 59%,Motorized Artisanal Fishing is 25%,and Semi-industrial fishing is 16%.In Motorized Artisanal Fishing,the Guineans have committed 33,the Senegalese have committed 23,and the Leonese have committed 18.In Semi-industrial fishing,the Chinese have committed 17 and the Senegalese have committed 16.According to the stakeholder survey,Vessal Monitoring System monitored 79 vessels in industrial fishing and 49 in Semi-industrial fishing in 2021.Registration certificates,personnel,rescue gear,gross tonnage,coastal state fishing authority,and maritime radio license are typically the primary documents examined at sea.From 2006 to 2022,a total of 135 fleets-80 demersal trawlers,7 cephalopod boats,21 shrimp boats,22 pelagic trawlers,and 5 cargo ships-were implicated in violations in the Guinean exclusive and economic area.By integrating the automatic identification system and Vessal Monitoring systems for fisheries surveillance,establishing a marking system for fishing gear,investing in highly effective launches,and protecting the privacy of patrol activities,Guinea’s surveillance system might be improved more effectively.展开更多
The influences of different factors,including whether the transverse frames are actually built,longitudinal and transverse welding residual stresses,and unloaded edge boundaries,on the ultimate strength and failure mo...The influences of different factors,including whether the transverse frames are actually built,longitudinal and transverse welding residual stresses,and unloaded edge boundaries,on the ultimate strength and failure mode of a real hull bottom full-scale stiffened plate under axial compression and lateral pressure are investigated via numerical analysis.Result shows that the failure mode of the stiffened plate under axial compression is the tripping of the stiffeners.Whether transverse frames are built has little effect on the ultimate strength of the stiffened plate under axial compression,which can be replaced by the degree of freedom constraint.However,when lateral pressure is present,the transverse frame cannot be simply replaced by a free-degree constraint.The longitudinal residual stress has a greater effect on the ultimate strength,whereas the effect of the transverse residual stress is smaller.Stronger unloaded edge boundary conditions can slightly enhance the stiffness and ultimate strength of the stiffened plate.Under combined axial compression and lateral pressure,the failure mode of stiffened plates changes from the tripping of stiffeners to beam-column failure,as the lateral pressure increases.The ability of stiffened plates in which transverse frames are actually built out to resist beam-column shape deformation becomes weaker with lower ultimate strength.Stronger unloaded edge boundary conditions can improve the ability of stiffened plates to resist beam-column deformation and increase the ultimate strength.展开更多
In the process of developing oil and gas resources in the Arctic,the impact of icebergs can pose a considerable threat to the structural safety of semi-submersible mooring platforms in ice regions.On the basis of the ...In the process of developing oil and gas resources in the Arctic,the impact of icebergs can pose a considerable threat to the structural safety of semi-submersible mooring platforms in ice regions.On the basis of the arbitrary Lagrangian Eulerian(ALE)algorithm,a numerical model for the interaction between an iceberg and a semi-submersible mooring platform is built in this work.First,a mooring system with a link element is designed and validated.An ice material model for the target iceberg is built and validated.A numerical model for the interaction between an iceberg and a semi-submersible mooring platform is then built.A parametric study(cable angle,tension angle and number of cables)is carried out to study the performance of the mooring system.The collision process between the semi-submersible mooring platform and the iceberg in the polar marine environment can be predicted by the present numerical model,and then the optimal mooring arrangement scheme can be obtained.The research results in this work can provide a reference for the design of mooring systems.展开更多
Variable ballast systems are necessary for manned submersibles to adjust their buoyancy.In this paper,the design of a variable ballast system for a manned submersible is described.The variable ballast system uses a su...Variable ballast systems are necessary for manned submersibles to adjust their buoyancy.In this paper,the design of a variable ballast system for a manned submersible is described.The variable ballast system uses a super high pressure hydraulic seawater system.A super high pressure seawater pump and a deep-sea brushless DC motor are used to pump seawater into or from the variable ballast tank,increasing or decreasing the weight of the manned submersible.A magnetostrictive linear displacement transducer can detect the seawater level in the variable ballast tank.Some seawater valves are used to control pumping direction and control on-off states.The design and testing procedure for the valves is described.Finally,the future development of variable ballast systems and seawater hydraulic systems is projected.展开更多
This paper outlines the basic concept of knowledge graph and its unique advantages, and explains in detail its approach to processing complex data structures through data integration, relationship discovery and semant...This paper outlines the basic concept of knowledge graph and its unique advantages, and explains in detail its approach to processing complex data structures through data integration, relationship discovery and semantic understanding. Knowledge graphs utilize a combination of technologies such as entities, attributes, relationships, and semantic annotations to demonstrate indispensable functionality in standardization processes, and especially excel in achieving semantic connectivity. This paper systematically analyzes the role of knowledge graph in each level using the standards hierarchical model as a framework. In Level 1, knowledge graph supports information extraction and preliminary tagging;in Level 2, it realizes structured and semantic processing of documents;in Level 3, it facilitates complex relationship modeling and executive integration;and it lays the foundation for advanced intelligent applications, autonomous standards governance and dynamic automatic updating in Level 4 and 5. This paper provides an in-depth discussion of its future directions and possible challenges, including key topics such as optimizing the scalability of knowledge graphs and facilitating cross-domain knowledge fusion. It shows that knowledge graphs provide powerful technical support for standards digitization and offer new possibilities for realizing smart manufacturing and cross-domain collaboration.展开更多
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc...To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.展开更多
The operation of deep-sea underwater vehicles relies entirely on onboard batteries.However,the extreme deep-sea conditions,characterized by ultrahigh hydraulic pressure,low temperature,and seawater conductivity,pose s...The operation of deep-sea underwater vehicles relies entirely on onboard batteries.However,the extreme deep-sea conditions,characterized by ultrahigh hydraulic pressure,low temperature,and seawater conductivity,pose significant challenges for battery development.These conditions drive the need for specialized designs in deep-sea batteries,incorporating critical aspects of power generation,protection,distribution,and management.Over time,deep-sea battery technology has evolved through multiple generations,with lithium(Li)batteries emerging in recent decades as the preferred power source due to their high energy and reduced operational risks.Although the rapid progress of Li batteries has notably advanced the capabilities of underwater vehicles,critical technical issues remain unresolved.This review first systematically presents the whole picture of deep-sea battery manufacturing,focusing on Li batteries as the current mainstream solution for underwater power.It examines the key aspects of deep-sea Li battery development,including materials selection informed by electro-chemo-mechanics models,component modification and testing,and battery management systems specialized in software and hardware.Finally,it discusses the main challenges limiting the utilization of deep-sea batteries and outlines promising directions for future development.Based on the systematic reflection on deep-sea batteries and discussion on deep-sea Li batteries,this review aims to provide a research foundation for developing underwater power tailored for extreme environmental exploration.展开更多
Ice load on underwater vehicles breaking through ice covers from underneath is a significant concern for researchers in polar exploration,and the research on this problem is still in its early stages.Both mechanical e...Ice load on underwater vehicles breaking through ice covers from underneath is a significant concern for researchers in polar exploration,and the research on this problem is still in its early stages.Both mechanical experimental measurement and numerical simulation pose research challenges.This study focuses on the ice load of a cylinder structure breaking upward through the ice sheet form underneath in the Small Ice Model Basin of China Ship Scientific Research Center(CSSRC SIMB).A high-speed camera system was employed to observe the ice sheet failure during the tests,in which,with the loading position as center,local radial cracks and circumferential cracks were generated.A load sensor was used to measure the overall ice load during this process.Meanwhile,a numerical model was developed using LS-DYNA for validation and comparison.With this model,numerical simulation was conducted under various ice thicknesses and upgoing speeds to analyze the instantaneous curves of ice load.The calculation results were statistically analyzed under different working conditions to determine the influence of the factors on the ice load of the cylinder.The study explores the measurement method about ice load of objects vertically breaking through model ice sheet and is expected to provide some fundamental insights into the safety design of underwater structures operating in ice waters.展开更多
Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data...Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data that mooring system designers aim to acquire.To address the need for long-term continuous monitoring of mooring tension in deep-sea marine environments,this paper presents a mooring cable tension monitoring method based on the principle of direct mechanical measurement.The developed tension monitoring sensors were installed and applied in the mooring system of the"Yongle"scientific experimental platform.Over the course of one year,a substantial amount of in-situ tension monitoring data was obtained.Under wave heights of up to 1.24 m,the mooring tension on the floating platform reached 16.5 tons.Through frequency domain and time domain analysis,the spectral characteristics of mooring tension,including waveinduced force,slow drift force,and mooring cable elastic restoring force,were determined.The mooring cable elastic restoring force frequency was approximately half of that of the wave signal.Due to the characteristics of the hinge connection structure of the dual module floating platform,under some specific working conditions the wave-induced force was the maximum of the three different frequency forces,and restoring force was the smallest.展开更多
As a typical steel,the fatigue of marine high-strength steels has been emphasized by scholars.In this paper,the fatigue performance and crack growth mechanism of a high-strength steel for ships are investigated by exp...As a typical steel,the fatigue of marine high-strength steels has been emphasized by scholars.In this paper,the fatigue performance and crack growth mechanism of a high-strength steel for ships are investigated by experimental methods.First,the fatigue threshold test and fatigue crack growth rate test of this high-strength steel under different stress ratios were carried out.The influence of stress ratio on the fatigue properties of this steel was analyzed.Secondly,scanning electron microscope was used to analyze the crack growth specimen section of this steel.The crack growth and failure mechanism of this steel were revealed.Finally,based on the above research results,the stress ratio effect of high-strength steel was investigated from the perspectives of crack closure and driving force.Considering the fatigue behavior in the near-threshold stage and the destabilization stage,a fatigue crack growth behavior prediction model of highstrength steel was established.The accuracy of the model was verified by test data.Moreover,the applicability of the modified model to various materials and its excellent predictive ability were verified through comparison with literature data and existing models.展开更多
The incidence and mortality rate of lung cancer rank among the highest worldwide,severely endangering human health and life.Metformin,an anti-diabetes drug,has been shown to elicit anticancer activities in various tum...The incidence and mortality rate of lung cancer rank among the highest worldwide,severely endangering human health and life.Metformin,an anti-diabetes drug,has been shown to elicit anticancer activities in various tumors.However,its underlying mechanisms remain elusive.In this work,we explore the role of receptor-interacting protein 1(RIP1)which plays a crucial role in the process of cell death,in metformin-induced anticancer activities in lung cancer.Metformin inhibits lung cancer cell proliferation in a dose-dependent manner and promotes apoptotic cell death,as evidenced by metformin-induced PARP and caspase cleavage.Furthermore,the pan-caspase inhibitor z-VAD-fmk reverses metformin-induced cell death.Western blot and qPCR results suggest that metformin markedly downregulates RIP1 expression without affecting its mRNA and ubiquitination levels(0 vs 80 mmol/L,100%vs 20%,100%vs 15%).Additionally,co-immunoprecipitation and immunofluorescence results reveal that metformin may suppress RIP1 expression in an Hsp70-dependent manner,as metformin promotes Hsp70 degradation,and Hsp70 endogenously interacts with RIP1.Subsequent CCK-8,flow cytometry,and Western blot analyses suggest that metformin decreases Hsp70/RIP1 expression through AMPK/PKA/GSK-3βaxis.Consistently,results from a subcutaneous transplant tumor model indicate that metformin retards tumor growth without affecting mouse body weight.Collectively,these data highlight the part of RIP1 in metformin-induced anticancer activities in lung cancer in vitro and in vivo,providing novel strategy for lung cancer administration.展开更多
Humans have always engaged with their surroundings and the ecology in which they live.However,during the industrial age,this contact has been more intense and has had a substantial impact on environment and ecosystems...Humans have always engaged with their surroundings and the ecology in which they live.However,during the industrial age,this contact has been more intense and has had a substantial impact on environment and ecosystems.For example,overexploitation of natural resources,mining,pollution,and deforestation are all elements that negatively affect biodiversity and natural resources.Few studies have been conducted to evaluate the damage caused,despite the significant uncontrolled pressure from human activity.However,maintaining its environment is essential to the survival of coastal fishing.Goal:This study’s goal was to evaluate how human activity affected Tabounsou’s coastal ecology in order to suggest remedial actions for sustainable management.The following was the methodological approach used:executive consultation and archival analysis;stakeholder survey(locals,farmers,salt producers,fishers,and loggers);inventory of species;anthropogenic activity inventory;evaluation of how human activity affects aquatic life in the research region;suggestion and action for sustainable management;Outcome:Executive consultation indicated that the main issues are:construction projects that reduce the estuary’s surface area;agricultural practices such as woodcutting and salt farming;the rise in resource exploitation;noncompliance with fisheries laws;and the catching of young fish.Eighty-three percent of fisherman ditch their nets on the coast after using them,but only seventeen percent burn them.With a 75%frequency rate,the same survey indicates that most fisherman fish around the coast.In the Tabounsou area,according to loggers’survey,68%of the wood cut is Rhizophora,24%is Avicennia,and 8%is Laguncularia.Three fish stocks,representing nine families and nine species,were identified by the species inventory.At 18%and 15%,respectively,the actors most frequently capture the species Pseudotolithus elongatus and Arius parkii.According to a poll of 30 farmers,90%of them apply fertilizer to their soil,while only 10%do not.During the dry season,salt is grown.According to two actors,Bougna Toro Toro produces 100 kg of salt per day,followed by Khoumawadé,which produces 80 kg,and Toumbibougni,which produces 70 kg.展开更多
During strong unsteady flow processes such as cavitation initiation and collapse,the volume changes generated by the materials transformation of cavitation phase transition seriously lag behind the volume evolution fo...During strong unsteady flow processes such as cavitation initiation and collapse,the volume changes generated by the materials transformation of cavitation phase transition seriously lag behind the volume evolution formed by the flow process.The phase transition and hydrodynamics are in a non-equilibrium state.A cavitation model that can describe such non-equilibrium phenomena is needed in numerical simulations of cavitation flow.The paper starts from the molecular dynamics’principle of phase change of matter,and based on the Maxwell velocity distribution form of molecular thermal motion,elaborates on the formation process of Hertz Knudsen formula for material exchange at the interface between liquid and vapor.On this basis,using the evolution equation of gas nucleus number density in water and the compressible state equation of vapor,a non-equilibrium cavitation model for phase transition and hydrodynamics is established.The simulation results of a vapor bubble collapse process in the non-equilibrium cavitation model show different behavior from the simulation results of the equilibrium cavitation model.The simulation results of the equilibrium cavitation model show that the vapor bubble collapses once and completely disappear,while the simulation results of the non-equilibrium cavitation model show multiple collapses and rebound,which is agreement with the experimental results of the vapor bubble collapse.展开更多
Chronic hepatitis B virus(HBV)infection remains a major health burden worldwide.To establish a persistence infection,HBV needs to evade both adaptive and innate immune surveillance.Multiple mechanisms for adaptive imm...Chronic hepatitis B virus(HBV)infection remains a major health burden worldwide.To establish a persistence infection,HBV needs to evade both adaptive and innate immune surveillance.Multiple mechanisms for adaptive immunity evasion have been established,but how HBV evades the innate surveillance is less clear.There are three types of host cells involving in the innate immune responses against HBV infection:Hepatocytes,hepatic nonparenchymal cells and conventional innate immune cells.Among these,hepatocytes are the only target cells that are susceptible to HBV infection and the only confirmed site where HBV replication takes place.This review focuses on the hepatocyte-intrinsic innate immunity;one of the earliest host defense responses.After entering hepatocytes,the viral components can be sensed by the cellular pattern recognition receptors.This triggers downstream antiviral responses capable of inhibiting viral replication and even degrading the viral DNA genome directly or indirectly.However,HBV has evolved a variety of sophisticated strategies to evade intracellular immune defense,resulting in the establishment of infection.Here,we provide insights into the mechanisms of the intrinsic innate immune response of hepatocytes and how HBV escapes these defense mechanisms.Hopefully,this will lay the foundation for the development of novel anti-HBV therapies.展开更多
Polymethyl methacrylate(PMMA)has the advantages of good transparency,corrosion resistance and light weight and can be used as the preferred material for pressure-resistant cabins of fully transparent submersibles.In t...Polymethyl methacrylate(PMMA)has the advantages of good transparency,corrosion resistance and light weight and can be used as the preferred material for pressure-resistant cabins of fully transparent submersibles.In this study,based on the fracture mechanics method,a calculation method for estimating the residual fatigue life of a PMMA manned cabin is proposed by improving the small-time scale fatigue crack growth rate model.This improved model is verified by the experimental data of the PMMA material.Then,through the Weibull and Gumbel combined distribution functions,the fatigue load spectrum suitable for the fully transparent manned cabin is fitted according to the dive data.A parametric analysis of the residual fatigue life of the fully transparent manned cabin under various initial crack sizes and dwell time is conducted,yielding valuable results.This study aims to increase the safety of fully transparent pressure-resistant cabins and offer insights for fatigue analysis of underwater structures utilizing PMMA materials.展开更多
The color difference of capsicum fruit is closely related to the type and content of pigment in the peel,which is mainly determined by anthocyanins,chlorophyll,and carotenoids.This study used green“CA59”and purple“...The color difference of capsicum fruit is closely related to the type and content of pigment in the peel,which is mainly determined by anthocyanins,chlorophyll,and carotenoids.This study used green“CA59”and purple“Z81”pepper fruits as parents to create the F2 generation.The fruit color of 466 F2 population was identified,and the extreme individuals from this population were selected for Bulked Segregant Analysis(BSA)using resequencing.Genetic analysis revealed that a pair of genes controls the expression of the purple fruit trait in capsicum.Using functional annotation,expression analysis,and sequencing analysis of candidate genes,it was determined that there were four genes in the region between InDel 67 and InDel 75(185,664,068 BP-186,514,350 bp)on chromosome 10,that is the linkage interval for pepper purple fruit.There are 7 SNPs in the CaMYB1 gene(Capann_59V1aChr10g016200)in the pepper variety“Z81”.Of these,4 SNPs are located in the gene’s coding region.These 4 SNPs lead to 2 mutations that do not change the amino acid sequence(synonymous mutations)and 2 mutations that do change the amino acid sequence(non-synonymous mutations).Additionally,the expression level of the CaMYB1 gene in the purple fruit of“Z81”is significantly higher than that in the green fruit of“CA59”.CaMYB1 is believed to be a crucial candidate gene in regulating anthocyanin production in purple capsicum fruit.A molecular marker,InDel 67,was successfully developed,with a total separation rate of 92.4%.展开更多
Addressing the issue of excessive cavitation pressure fluctuation on the propeller behind a catamaran,numerical simulation is conducted to assess the quality of the wake flow and to numerically predict the pressure fl...Addressing the issue of excessive cavitation pressure fluctuation on the propeller behind a catamaran,numerical simulation is conducted to assess the quality of the wake flow and to numerically predict the pressure fluctuation induced by the propeller cavitation.Additionally,the interaction between the wake vortex field and the propeller is investigated,revealing the presence of propeller-hull vortex.To improve the propeller's inflow quality,the impact of vortex generators on the wake flow and pressure fluctuation is numerically simulated.Then,numerical simulations are conducted to compare the cavitation pressure fluctuation of optimized propeller design,evaluating the effects of vortex generators at different spatial locations and angles of attack,to determine the optimal vortex generator scheme.A more comprehensive integrated control plan for the wake flow and the cavitation pressure fluctuation of the propeller behind the catamaran is finally formed.展开更多
The underwater launch of an axisymmetric body involves complex cavity-structure interactions.Studying the evolution of cavity pressure around an axisymmetric body is crucial for researching its motion stability.In thi...The underwater launch of an axisymmetric body involves complex cavity-structure interactions.Studying the evolution of cavity pressure around an axisymmetric body is crucial for researching its motion stability.In this work,we propose a deep neural network model for cavity pressure distribution recovery,called CPDR-net.This model can reconstruct the full-domain distribution of surface pressure based solely on the local pressure distribution.The CPDR-net model was trained using numerical simulation data with different launch depths and initial velocities,and subsequently tested on two simulation datasets under new conditions.Both training and testing datasets are obtained from the ventilated cavitating flow over an underwater axisymmetric vehicle.Results demonstrated that CPDR-net can accurately predict the pressure distribution along each longitudinal line of the axisymmetric body and provide the pressure evolution over time for each point on the surface.Thus,we can obtain the evolution of surface pressure distribution throughout the entire voyage process based on the CPDR-net model.The findings from this study may provide a valuable reference for subsequent research on underwater launches.展开更多
Dear Editor,This letter focuses on the fact that small objects with few pixels disappear in feature maps with large receptive fields, as the network deepens, in object detection tasks. Therefore, the detection of dens...Dear Editor,This letter focuses on the fact that small objects with few pixels disappear in feature maps with large receptive fields, as the network deepens, in object detection tasks. Therefore, the detection of dense small objects is challenging.展开更多
To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistat...To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.展开更多
文摘This work’s goal was to compile a list of fishing-related violations in order to suggest ways to enhance the surveillance system.In order to accomplish this goal,the following approach was used:Executive consultation and archive exploitation;surveillance agent survey;surveillance system identification and description;identification of offenses and fleet involved in the Guinean exclusive and economic area in recent years;identification and categorization of offense causes;surveillance system evaluation;and suggestion for enhanced surveillance system measures.Monitoring of this strategy showed that:fishing operating zones,administrative paperwork,and fishing gear are all linked to the infractions committed in the Guinean exclusive and economic zone.Records show that there were 308 boardings between 2006 and 2021.IP(Intellectual Property)infringement rates are 59%,Motorized Artisanal Fishing is 25%,and Semi-industrial fishing is 16%.In Motorized Artisanal Fishing,the Guineans have committed 33,the Senegalese have committed 23,and the Leonese have committed 18.In Semi-industrial fishing,the Chinese have committed 17 and the Senegalese have committed 16.According to the stakeholder survey,Vessal Monitoring System monitored 79 vessels in industrial fishing and 49 in Semi-industrial fishing in 2021.Registration certificates,personnel,rescue gear,gross tonnage,coastal state fishing authority,and maritime radio license are typically the primary documents examined at sea.From 2006 to 2022,a total of 135 fleets-80 demersal trawlers,7 cephalopod boats,21 shrimp boats,22 pelagic trawlers,and 5 cargo ships-were implicated in violations in the Guinean exclusive and economic area.By integrating the automatic identification system and Vessal Monitoring systems for fisheries surveillance,establishing a marking system for fishing gear,investing in highly effective launches,and protecting the privacy of patrol activities,Guinea’s surveillance system might be improved more effectively.
基金financially supported by the National Natural Science Foundation of China(Grant No.52001040),the Natural Science Foundation Project of Chongqing,Chongqing Science and Technology Commission(Grant No.cstc2021jcyj-msxmX0944)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202300710).
文摘The influences of different factors,including whether the transverse frames are actually built,longitudinal and transverse welding residual stresses,and unloaded edge boundaries,on the ultimate strength and failure mode of a real hull bottom full-scale stiffened plate under axial compression and lateral pressure are investigated via numerical analysis.Result shows that the failure mode of the stiffened plate under axial compression is the tripping of the stiffeners.Whether transverse frames are built has little effect on the ultimate strength of the stiffened plate under axial compression,which can be replaced by the degree of freedom constraint.However,when lateral pressure is present,the transverse frame cannot be simply replaced by a free-degree constraint.The longitudinal residual stress has a greater effect on the ultimate strength,whereas the effect of the transverse residual stress is smaller.Stronger unloaded edge boundary conditions can slightly enhance the stiffness and ultimate strength of the stiffened plate.Under combined axial compression and lateral pressure,the failure mode of stiffened plates changes from the tripping of stiffeners to beam-column failure,as the lateral pressure increases.The ability of stiffened plates in which transverse frames are actually built out to resist beam-column shape deformation becomes weaker with lower ultimate strength.Stronger unloaded edge boundary conditions can improve the ability of stiffened plates to resist beam-column deformation and increase the ultimate strength.
基金financially supported by the Open Project Program of Shandong Marine Aerospace Equipment Technological Innovation Center,Ludong University(Grant Nos.MAETIC202209 and MAETIC202201)Shandong Provincial Natural Science Foundation(Grant No.ZR2022QE092)+2 种基金China Postdoctoral Science Foundation(Grant No.2023M730829)Open Fund of the State Key Laboratory of Industrial Equipment Structural Analysis(Grant No.GZ23109)the National Natural Science Foundation of China(Grant Nos.52001284 and 52192694).
文摘In the process of developing oil and gas resources in the Arctic,the impact of icebergs can pose a considerable threat to the structural safety of semi-submersible mooring platforms in ice regions.On the basis of the arbitrary Lagrangian Eulerian(ALE)algorithm,a numerical model for the interaction between an iceberg and a semi-submersible mooring platform is built in this work.First,a mooring system with a link element is designed and validated.An ice material model for the target iceberg is built and validated.A numerical model for the interaction between an iceberg and a semi-submersible mooring platform is then built.A parametric study(cable angle,tension angle and number of cables)is carried out to study the performance of the mooring system.The collision process between the semi-submersible mooring platform and the iceberg in the polar marine environment can be predicted by the present numerical model,and then the optimal mooring arrangement scheme can be obtained.The research results in this work can provide a reference for the design of mooring systems.
基金Supported by the "863" Foundation under Grant No.2002AA401000
文摘Variable ballast systems are necessary for manned submersibles to adjust their buoyancy.In this paper,the design of a variable ballast system for a manned submersible is described.The variable ballast system uses a super high pressure hydraulic seawater system.A super high pressure seawater pump and a deep-sea brushless DC motor are used to pump seawater into or from the variable ballast tank,increasing or decreasing the weight of the manned submersible.A magnetostrictive linear displacement transducer can detect the seawater level in the variable ballast tank.Some seawater valves are used to control pumping direction and control on-off states.The design and testing procedure for the valves is described.Finally,the future development of variable ballast systems and seawater hydraulic systems is projected.
文摘This paper outlines the basic concept of knowledge graph and its unique advantages, and explains in detail its approach to processing complex data structures through data integration, relationship discovery and semantic understanding. Knowledge graphs utilize a combination of technologies such as entities, attributes, relationships, and semantic annotations to demonstrate indispensable functionality in standardization processes, and especially excel in achieving semantic connectivity. This paper systematically analyzes the role of knowledge graph in each level using the standards hierarchical model as a framework. In Level 1, knowledge graph supports information extraction and preliminary tagging;in Level 2, it realizes structured and semantic processing of documents;in Level 3, it facilitates complex relationship modeling and executive integration;and it lays the foundation for advanced intelligent applications, autonomous standards governance and dynamic automatic updating in Level 4 and 5. This paper provides an in-depth discussion of its future directions and possible challenges, including key topics such as optimizing the scalability of knowledge graphs and facilitating cross-domain knowledge fusion. It shows that knowledge graphs provide powerful technical support for standards digitization and offer new possibilities for realizing smart manufacturing and cross-domain collaboration.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX24_0714).
文摘To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.
基金support provided by National Key Research and Development Program of China(2023YFE0203000 and 2016YFC0300200)the NSAF(Grant No.U2330205)+3 种基金Full-Sea-Depth Battery Project(2020-XXXX-XX-246-00)Open project of Shaanxi Laboratory of Aerospace Power(2022ZY2-JCYJ-01-09)Fundamental Research Funds for the Central Universities,ND Basic Research Funds(G2022WD)the Innovation Team of Shaanxi Province。
文摘The operation of deep-sea underwater vehicles relies entirely on onboard batteries.However,the extreme deep-sea conditions,characterized by ultrahigh hydraulic pressure,low temperature,and seawater conductivity,pose significant challenges for battery development.These conditions drive the need for specialized designs in deep-sea batteries,incorporating critical aspects of power generation,protection,distribution,and management.Over time,deep-sea battery technology has evolved through multiple generations,with lithium(Li)batteries emerging in recent decades as the preferred power source due to their high energy and reduced operational risks.Although the rapid progress of Li batteries has notably advanced the capabilities of underwater vehicles,critical technical issues remain unresolved.This review first systematically presents the whole picture of deep-sea battery manufacturing,focusing on Li batteries as the current mainstream solution for underwater power.It examines the key aspects of deep-sea Li battery development,including materials selection informed by electro-chemo-mechanics models,component modification and testing,and battery management systems specialized in software and hardware.Finally,it discusses the main challenges limiting the utilization of deep-sea batteries and outlines promising directions for future development.Based on the systematic reflection on deep-sea batteries and discussion on deep-sea Li batteries,this review aims to provide a research foundation for developing underwater power tailored for extreme environmental exploration.
文摘Ice load on underwater vehicles breaking through ice covers from underneath is a significant concern for researchers in polar exploration,and the research on this problem is still in its early stages.Both mechanical experimental measurement and numerical simulation pose research challenges.This study focuses on the ice load of a cylinder structure breaking upward through the ice sheet form underneath in the Small Ice Model Basin of China Ship Scientific Research Center(CSSRC SIMB).A high-speed camera system was employed to observe the ice sheet failure during the tests,in which,with the loading position as center,local radial cracks and circumferential cracks were generated.A load sensor was used to measure the overall ice load during this process.Meanwhile,a numerical model was developed using LS-DYNA for validation and comparison.With this model,numerical simulation was conducted under various ice thicknesses and upgoing speeds to analyze the instantaneous curves of ice load.The calculation results were statistically analyzed under different working conditions to determine the influence of the factors on the ice load of the cylinder.The study explores the measurement method about ice load of objects vertically breaking through model ice sheet and is expected to provide some fundamental insights into the safety design of underwater structures operating in ice waters.
文摘Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data that mooring system designers aim to acquire.To address the need for long-term continuous monitoring of mooring tension in deep-sea marine environments,this paper presents a mooring cable tension monitoring method based on the principle of direct mechanical measurement.The developed tension monitoring sensors were installed and applied in the mooring system of the"Yongle"scientific experimental platform.Over the course of one year,a substantial amount of in-situ tension monitoring data was obtained.Under wave heights of up to 1.24 m,the mooring tension on the floating platform reached 16.5 tons.Through frequency domain and time domain analysis,the spectral characteristics of mooring tension,including waveinduced force,slow drift force,and mooring cable elastic restoring force,were determined.The mooring cable elastic restoring force frequency was approximately half of that of the wave signal.Due to the characteristics of the hinge connection structure of the dual module floating platform,under some specific working conditions the wave-induced force was the maximum of the three different frequency forces,and restoring force was the smallest.
文摘As a typical steel,the fatigue of marine high-strength steels has been emphasized by scholars.In this paper,the fatigue performance and crack growth mechanism of a high-strength steel for ships are investigated by experimental methods.First,the fatigue threshold test and fatigue crack growth rate test of this high-strength steel under different stress ratios were carried out.The influence of stress ratio on the fatigue properties of this steel was analyzed.Secondly,scanning electron microscope was used to analyze the crack growth specimen section of this steel.The crack growth and failure mechanism of this steel were revealed.Finally,based on the above research results,the stress ratio effect of high-strength steel was investigated from the perspectives of crack closure and driving force.Considering the fatigue behavior in the near-threshold stage and the destabilization stage,a fatigue crack growth behavior prediction model of highstrength steel was established.The accuracy of the model was verified by test data.Moreover,the applicability of the modified model to various materials and its excellent predictive ability were verified through comparison with literature data and existing models.
文摘The incidence and mortality rate of lung cancer rank among the highest worldwide,severely endangering human health and life.Metformin,an anti-diabetes drug,has been shown to elicit anticancer activities in various tumors.However,its underlying mechanisms remain elusive.In this work,we explore the role of receptor-interacting protein 1(RIP1)which plays a crucial role in the process of cell death,in metformin-induced anticancer activities in lung cancer.Metformin inhibits lung cancer cell proliferation in a dose-dependent manner and promotes apoptotic cell death,as evidenced by metformin-induced PARP and caspase cleavage.Furthermore,the pan-caspase inhibitor z-VAD-fmk reverses metformin-induced cell death.Western blot and qPCR results suggest that metformin markedly downregulates RIP1 expression without affecting its mRNA and ubiquitination levels(0 vs 80 mmol/L,100%vs 20%,100%vs 15%).Additionally,co-immunoprecipitation and immunofluorescence results reveal that metformin may suppress RIP1 expression in an Hsp70-dependent manner,as metformin promotes Hsp70 degradation,and Hsp70 endogenously interacts with RIP1.Subsequent CCK-8,flow cytometry,and Western blot analyses suggest that metformin decreases Hsp70/RIP1 expression through AMPK/PKA/GSK-3βaxis.Consistently,results from a subcutaneous transplant tumor model indicate that metformin retards tumor growth without affecting mouse body weight.Collectively,these data highlight the part of RIP1 in metformin-induced anticancer activities in lung cancer in vitro and in vivo,providing novel strategy for lung cancer administration.
文摘Humans have always engaged with their surroundings and the ecology in which they live.However,during the industrial age,this contact has been more intense and has had a substantial impact on environment and ecosystems.For example,overexploitation of natural resources,mining,pollution,and deforestation are all elements that negatively affect biodiversity and natural resources.Few studies have been conducted to evaluate the damage caused,despite the significant uncontrolled pressure from human activity.However,maintaining its environment is essential to the survival of coastal fishing.Goal:This study’s goal was to evaluate how human activity affected Tabounsou’s coastal ecology in order to suggest remedial actions for sustainable management.The following was the methodological approach used:executive consultation and archival analysis;stakeholder survey(locals,farmers,salt producers,fishers,and loggers);inventory of species;anthropogenic activity inventory;evaluation of how human activity affects aquatic life in the research region;suggestion and action for sustainable management;Outcome:Executive consultation indicated that the main issues are:construction projects that reduce the estuary’s surface area;agricultural practices such as woodcutting and salt farming;the rise in resource exploitation;noncompliance with fisheries laws;and the catching of young fish.Eighty-three percent of fisherman ditch their nets on the coast after using them,but only seventeen percent burn them.With a 75%frequency rate,the same survey indicates that most fisherman fish around the coast.In the Tabounsou area,according to loggers’survey,68%of the wood cut is Rhizophora,24%is Avicennia,and 8%is Laguncularia.Three fish stocks,representing nine families and nine species,were identified by the species inventory.At 18%and 15%,respectively,the actors most frequently capture the species Pseudotolithus elongatus and Arius parkii.According to a poll of 30 farmers,90%of them apply fertilizer to their soil,while only 10%do not.During the dry season,salt is grown.According to two actors,Bougna Toro Toro produces 100 kg of salt per day,followed by Khoumawadé,which produces 80 kg,and Toumbibougni,which produces 70 kg.
文摘During strong unsteady flow processes such as cavitation initiation and collapse,the volume changes generated by the materials transformation of cavitation phase transition seriously lag behind the volume evolution formed by the flow process.The phase transition and hydrodynamics are in a non-equilibrium state.A cavitation model that can describe such non-equilibrium phenomena is needed in numerical simulations of cavitation flow.The paper starts from the molecular dynamics’principle of phase change of matter,and based on the Maxwell velocity distribution form of molecular thermal motion,elaborates on the formation process of Hertz Knudsen formula for material exchange at the interface between liquid and vapor.On this basis,using the evolution equation of gas nucleus number density in water and the compressible state equation of vapor,a non-equilibrium cavitation model for phase transition and hydrodynamics is established.The simulation results of a vapor bubble collapse process in the non-equilibrium cavitation model show different behavior from the simulation results of the equilibrium cavitation model.The simulation results of the equilibrium cavitation model show that the vapor bubble collapses once and completely disappear,while the simulation results of the non-equilibrium cavitation model show multiple collapses and rebound,which is agreement with the experimental results of the vapor bubble collapse.
基金Supported by Shenzhen Medical Research Fund,No.D2301010Shenzhen Science and Technology Program,No.RCYX20231211090346060。
文摘Chronic hepatitis B virus(HBV)infection remains a major health burden worldwide.To establish a persistence infection,HBV needs to evade both adaptive and innate immune surveillance.Multiple mechanisms for adaptive immunity evasion have been established,but how HBV evades the innate surveillance is less clear.There are three types of host cells involving in the innate immune responses against HBV infection:Hepatocytes,hepatic nonparenchymal cells and conventional innate immune cells.Among these,hepatocytes are the only target cells that are susceptible to HBV infection and the only confirmed site where HBV replication takes place.This review focuses on the hepatocyte-intrinsic innate immunity;one of the earliest host defense responses.After entering hepatocytes,the viral components can be sensed by the cellular pattern recognition receptors.This triggers downstream antiviral responses capable of inhibiting viral replication and even degrading the viral DNA genome directly or indirectly.However,HBV has evolved a variety of sophisticated strategies to evade intracellular immune defense,resulting in the establishment of infection.Here,we provide insights into the mechanisms of the intrinsic innate immune response of hepatocytes and how HBV escapes these defense mechanisms.Hopefully,this will lay the foundation for the development of novel anti-HBV therapies.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC2800600)the National Natural Science Foundation of China(Grant No.52071203).
文摘Polymethyl methacrylate(PMMA)has the advantages of good transparency,corrosion resistance and light weight and can be used as the preferred material for pressure-resistant cabins of fully transparent submersibles.In this study,based on the fracture mechanics method,a calculation method for estimating the residual fatigue life of a PMMA manned cabin is proposed by improving the small-time scale fatigue crack growth rate model.This improved model is verified by the experimental data of the PMMA material.Then,through the Weibull and Gumbel combined distribution functions,the fatigue load spectrum suitable for the fully transparent manned cabin is fitted according to the dive data.A parametric analysis of the residual fatigue life of the fully transparent manned cabin under various initial crack sizes and dwell time is conducted,yielding valuable results.This study aims to increase the safety of fully transparent pressure-resistant cabins and offer insights for fatigue analysis of underwater structures utilizing PMMA materials.
基金supported by the National Natural Science Foundation of China(U2IA20230)the Guangdong Modern Vegetable Industry Technology System Project(2024CXTD08)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(2024A1515010403)the Xizang Autonomous Region of Lhasa City Science and Technology Project(LSKJ202418)the Guangdong Provincial Department of Agriculture and Rural Affairs(Selection and Breeding of New High-Yielding and High-Quality Pepper Varieties)(2024-NPY-00-020).
文摘The color difference of capsicum fruit is closely related to the type and content of pigment in the peel,which is mainly determined by anthocyanins,chlorophyll,and carotenoids.This study used green“CA59”and purple“Z81”pepper fruits as parents to create the F2 generation.The fruit color of 466 F2 population was identified,and the extreme individuals from this population were selected for Bulked Segregant Analysis(BSA)using resequencing.Genetic analysis revealed that a pair of genes controls the expression of the purple fruit trait in capsicum.Using functional annotation,expression analysis,and sequencing analysis of candidate genes,it was determined that there were four genes in the region between InDel 67 and InDel 75(185,664,068 BP-186,514,350 bp)on chromosome 10,that is the linkage interval for pepper purple fruit.There are 7 SNPs in the CaMYB1 gene(Capann_59V1aChr10g016200)in the pepper variety“Z81”.Of these,4 SNPs are located in the gene’s coding region.These 4 SNPs lead to 2 mutations that do not change the amino acid sequence(synonymous mutations)and 2 mutations that do change the amino acid sequence(non-synonymous mutations).Additionally,the expression level of the CaMYB1 gene in the purple fruit of“Z81”is significantly higher than that in the green fruit of“CA59”.CaMYB1 is believed to be a crucial candidate gene in regulating anthocyanin production in purple capsicum fruit.A molecular marker,InDel 67,was successfully developed,with a total separation rate of 92.4%.
文摘Addressing the issue of excessive cavitation pressure fluctuation on the propeller behind a catamaran,numerical simulation is conducted to assess the quality of the wake flow and to numerically predict the pressure fluctuation induced by the propeller cavitation.Additionally,the interaction between the wake vortex field and the propeller is investigated,revealing the presence of propeller-hull vortex.To improve the propeller's inflow quality,the impact of vortex generators on the wake flow and pressure fluctuation is numerically simulated.Then,numerical simulations are conducted to compare the cavitation pressure fluctuation of optimized propeller design,evaluating the effects of vortex generators at different spatial locations and angles of attack,to determine the optimal vortex generator scheme.A more comprehensive integrated control plan for the wake flow and the cavitation pressure fluctuation of the propeller behind the catamaran is finally formed.
基金supported by the Leading Talent Project for Scientific and Technological Innovation in Zhejiang Province(Grant No.2023R5220).
文摘The underwater launch of an axisymmetric body involves complex cavity-structure interactions.Studying the evolution of cavity pressure around an axisymmetric body is crucial for researching its motion stability.In this work,we propose a deep neural network model for cavity pressure distribution recovery,called CPDR-net.This model can reconstruct the full-domain distribution of surface pressure based solely on the local pressure distribution.The CPDR-net model was trained using numerical simulation data with different launch depths and initial velocities,and subsequently tested on two simulation datasets under new conditions.Both training and testing datasets are obtained from the ventilated cavitating flow over an underwater axisymmetric vehicle.Results demonstrated that CPDR-net can accurately predict the pressure distribution along each longitudinal line of the axisymmetric body and provide the pressure evolution over time for each point on the surface.Thus,we can obtain the evolution of surface pressure distribution throughout the entire voyage process based on the CPDR-net model.The findings from this study may provide a valuable reference for subsequent research on underwater launches.
基金supported in part by the National Science Foundation of China(52371372)the Project of Science and Technology Commission of Shanghai Municipality,China(22JC1401400,21190780300)the 111 Project,China(D18003)
文摘Dear Editor,This letter focuses on the fact that small objects with few pixels disappear in feature maps with large receptive fields, as the network deepens, in object detection tasks. Therefore, the detection of dense small objects is challenging.
基金supported by the National Natural Science Foundation of China(grant numbers:52201334)sup-ported by National Key Laboratory of Ship Structural Safety(grant numbers:Naklas2024-KF015-s).
文摘To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.
