Atmospheric radiation is a major branch of atmospheric physics that encompasses the fundamental theories of atmospheric absorption,particle scattering(aerosols and clouds),and radiative transfer.Specifically,the simul...Atmospheric radiation is a major branch of atmospheric physics that encompasses the fundamental theories of atmospheric absorption,particle scattering(aerosols and clouds),and radiative transfer.Specifically,the simulations of atmospheric gaseous absorption and scattering properties of particles are the essential components of atmospheric radiative transfer models.Atmospheric radiation has important applications in weather,climate,data assimilation,remote sensing,and atmospheric detection studies.In PartⅠ,a comprehensive review of the progress in the field of gas absorption and particle scattering research over the past 30 years with a particular emphasis on the contributions from Chinese scientists is presented.The review of gas absorption includes the construction of absorption databases,the impact of different atmospheric absorption algorithms on radiative calculations,and their applications in weather and climate models and remote sensing.The review on particle scattering starts with the theoretical and computational methods and subsequently explores the optical modeling of aerosols and clouds in remote sensing and atmospheric models.Additionally,the paper discusses potential future research directions in this field.展开更多
The rapid development of two-dimensional(2D)transition-metal dichalcogenides has been possible owing to their special structures and remarkable properties.In particular,palladium diselenide(PdSe_(2))with a novel penta...The rapid development of two-dimensional(2D)transition-metal dichalcogenides has been possible owing to their special structures and remarkable properties.In particular,palladium diselenide(PdSe_(2))with a novel pentagonal structure and unique physical characteristics have recently attracted extensive research inter-est.Consequently,tremendous research progress has been achieved regarding the physics,chemistry,and electronics of PdSe_(2).Accordingly,in this review,we recapitulate and summarize the most recent research on PdSe_(2),including its structure,properties,synthesis,and appli-cations.First,a mechanical exfoliation method to obtain PdSe_(2) nanosheets is introduced,and large-area synthesis strate-gies are explained with respect to chemical vapor deposition and metal selenization.Next,the electronic and optoelectronic properties of PdSe_(2) and related hetero-structures,such as field-effect transistors,photodetectors,sensors,and thermoelec-tric devices,are discussed.Subsequently,the integration of systems into infrared image sensors on the basis of PdSe_(2) van der Waals heterostructures is explored.Finally,future opportunities are highlighted to serve as a general guide for physicists,chemists,materials scientists,and engineers.Therefore,this com-prehensive review may shed light on the research conducted by the 2D material community.展开更多
This article provides an overview of the application of bionic technology in marine cruising equipment,discussing its research progress and future development trends.Marine cruising is a crucial means of gaining insig...This article provides an overview of the application of bionic technology in marine cruising equipment,discussing its research progress and future development trends.Marine cruising is a crucial means of gaining insights into the marine environment and conducting scientific research.However,conventional marine cruising equipment faces numerous challenges when dealing with complex and ever-changing marine environments.Bionic technology,as a means of drawing inspiration from the structure and functions of living organisms,offers new approaches and methods to address the challenges faced by marine cruising equipment and has found widespread application.The article primarily focuses on the applications and historical developments of bionic technology in propulsion methods,drag reduction,and surface antifouling.It summarizes the design principles,manufacturing techniques,and optimization methods for marine biomimetic cruising equipment.Finally,this paper analyzes the achievements,challenges,and future directions of bionic technology in marine cruising equipment.The application of bionic technology in marine cruising equipment holds vast potential for development,enabling us to better confront the challenges of marine exploration and research by drawing wisdom from nature and driving advancements in marine science.展开更多
Wind farms generally consist of a single turbine installed with the same hub height. As the scale of turbines increases,wake interference between turbines becomes increasingly significant, especially for floating wind...Wind farms generally consist of a single turbine installed with the same hub height. As the scale of turbines increases,wake interference between turbines becomes increasingly significant, especially for floating wind turbines(FWT).Some researchers find that wind farms with multiple hub heights could increase the annual energy production(AEP),while previous studies also indicate that wake meandering could increase fatigue loading. This study investigates the wake interaction within a hybrid floating wind farm with multiple hub heights. In this study, FAST.Farm is employed to simulate a hybrid wind farm which consists of four semi-submersible FWTs(5MW and 15MW) with two different hub heights. Three typical wind speeds(below-rated, rated, and over-rated) are considered in this paper to investigate the wake meandering effects on the dynamics of two FWTs. Damage equivalent loads(DEL) of the turbine critical components are computed and analyzed for several arrangements determined by the different spacing of the four turbines. The result shows that the dynamic wake meandering significantly affects downstream turbines’ global loadings and load effects. Differences in DEL show that blade-root flapwise bending moments and mooring fairlead tensions are sensitive to the spacing of the turbines.展开更多
A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The...A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The main dimension, the special variable cross-section column and the cabin arrangement of the octagonal pontoon are introduced based on the result. The numerical simulation is adapted to study the effects of current incidence angles and reduced velocities on this platform’s sway motion response. The 300 m water depth equivalent truncated mooring system is adopted for the model tests. The model tests are carried out to check the reliability of numerical simulation. The results consist of surge, sway and yaw motions, as well as motion trajectories. The maximum sway amplitudes for different types of offshore platform is also studied. The main results show that the peak frequencies of sway motion under different current incidence angles and reduced velocities vary around the natural frequency. The analysis result of flow field indicates that the change of distribution of vortex in vertical presents significant influences on the VIM of platform. The trend of sway amplitude ratio curve of this new type FDPSO differs from the other types of platform. Under 45° current incidence angle, the sway amplitude of this new type of FDPSO is much smaller than those of other types of offshore platform at 4.4 ≤ V;≤ 8.9. The typical ‘8’ shape trajectory does not appear in the platform’s motion trajectories.展开更多
As the anode material of lithium-ion battery,silicon-based materials have a high theoretical capacity,but their volume changes greatly in the charging and discharging process.To ameliorate the volume expansion issue o...As the anode material of lithium-ion battery,silicon-based materials have a high theoretical capacity,but their volume changes greatly in the charging and discharging process.To ameliorate the volume expansion issue of silicobased anode materials,g-C_(3)N_(4)/Si nanocomposites are prepared by using the magnesium thermal reduction technique.It is well known that g-C_(3)N_(4)/Si nanocomposites can not only improve the electronic transmission ability,but also ameliorate the physical properties of the material for adapting the stress and strain caused by the volume expansion of silicon in the lithiation and delithiation process.When g-C_(3)N_(4)/Si electrode is evaluated,the initial discharge capacity of g-C_(3)N_(4)/Si nanocomposites is as high as 1033.3 mAh/g at 0.1 A/g,and its reversible capacity is maintained at 548 mAh/g after 400 cycles.Meanwhile,the improved rate capability is achieved with a relatively high reversible specific capacity of 218 mAh/g at 2.0 A/g.The superior lithium storage performances benefit from the unique g-C_(3)N_(4)/Si nanostructure,which improves electroconductivity,reduces volume expansion,and accelerates lithiumion transmission compared to pure silicon.展开更多
Herein,we develop cost-efficient superhigh-performance of engineering carbonaceous adsorbent from cigarette butts using combined wet-impregnated and re-dispersed method of KOH,which optimizes the implant approach of a...Herein,we develop cost-efficient superhigh-performance of engineering carbonaceous adsorbent from cigarette butts using combined wet-impregnated and re-dispersed method of KOH,which optimizes the implant approach of activator,breaking the restriction of selective capture of toluene using traditional activated carbon.The Brunauer-Emmett-Teller(BET)surface area and pore volume of targeted adsorbent can attain 3088 m^(2)·g^(-1) and 1.61 cm^(3)·g^(-1),respectively,by optimizing the temperaturedependent synthetic factor effect of the adsorbent.The adsorption capacity of resultant adsorbent for presenting volatile benzene and toluene shows a positive correlation with increasing carbonization temperature of carbon precursor.Besides,we demonstrated the unsmoked and smoked butts derived adsorbents afford feeble difference in saturated adsorbed capacity of volatile organic compounds(VOCs).The highest adsorption capacity of sample CF-800 for benzene and toluene in CF group is as high as 1268.1 and 1181.6 mg·g^(-1) respectively,slightly higher than that of sample UF-800,but far outperforming reported other adsorbents.The predicted adsorption selectivity of CF-800 and UF-800 for C_(7)H_(8)/H_(2)O(g)using the DIH(difference of isosteric heats)equation reach up to ca.3800 and 7500 respectively,indicating the weak adsorbability of water vapor on the developed adsorbent and greater superiority of the smoked butts derived adsorbents in selective capture of VOCs at low relative humidity in the competitive adsorption process for practical mixed VOCs.展开更多
Outgoing waves arising from high-velocity impacts between soil and structure can be reflected by the conventional truncated boundaries.Absorbing boundary conditions(ABCs),to attenuate the energy of the outward waves,a...Outgoing waves arising from high-velocity impacts between soil and structure can be reflected by the conventional truncated boundaries.Absorbing boundary conditions(ABCs),to attenuate the energy of the outward waves,are necessary to ensure the proper representation of the kinematic field and the accurate quantification of impact forces.In this paper,damping layer and dashpot ABCs are implemented in the material point method(MPM)with slight adjustments.Benchmark scenarios of different dynamic problems are modelled with the ABCs configured.Feasibility of the ABCs is assessed through the velocity fluctuations at specific observation points and the impact force fluctuations on the structures.The impact forces predicted by the MPM with ABCs are verified by comparison with those estimated using a computational fluid dynamics approach.展开更多
Herb residue vermicompost is thought to have high agriculture value,while its effects on soil microbial activities have not been fully understood.Here,soil microbial biomass,respiration and enzyme activities in soil p...Herb residue vermicompost is thought to have high agriculture value,while its effects on soil microbial activities have not been fully understood.Here,soil microbial biomass,respiration and enzyme activities in soil planted with maize were compared among treatments amended with herb residue vermicompost at rates of 25,50,75 and 100 g kg^(-1),chemical NPK fertilizer and no fertilizer(the control).Our results showed that soil microbial biomass carbon,respiration,and alkaline phosphatase,urease,and invertase activities were greater in soil amended with herb residue vermicompost than the unfertilized control(P<0.05).Compared with chemical fertilizer,herb residue vermicompost increased soil urease and alkaline phosphatase activities at each application rate,promoted soil respiration and microbial biomass carbon at the application rates of 50,75 and 100 g kg^(-1),and increased soil inverse activity at the application rates of 75 and 100 g kg^(-1).In conclusion,herb residue vermicompost supported greater soil microbial biomass,respiration and enzyme activities than conventional NPK fertilizer,and the effect was larger when higher rates of herb residue vermicompost were added.展开更多
PbO2/Co3O4 composites were prepared on a Ti substrate by means of a composite electrodeposition method in Pb2+ plating solution containing dissolved nano-Co3O4 particles. X-ray diffraction（XRD）, scanning electron mi...PbO2/Co3O4 composites were prepared on a Ti substrate by means of a composite electrodeposition method in Pb2+ plating solution containing dissolved nano-Co3O4 particles. X-ray diffraction（XRD）, scanning electron microscopy（SEM）, energy dispersive spectrometry（EDS） and transmission electron microscopy（TEM） were used to characterize the chemical composition and morphology of the PbO2/Co3O4 composites. The electrochemical and capacitance performance of the composites were investigated by cyclic voltammetry（CV）, charge-discharge tests and electrochemical impedance（EIS）. The results indicate that the composites comprise rutile phase Co3O4 and β-PbO2. In addition, the surface of the composite electrode is rough and porous. The PbO2/Co3O4 composites exhibit a high specific capacitance up to 215 F/g, which is ten times higher than that of the pure-PbO2 and two times higher than that of the pure-Co3O4 in 1 mol/L NaOH electrolytes.展开更多
A 2.5-mm Fe72.5B15.6Si7.8Nb1.7Zr1.7Cu0.7 glassy rod was successfully fabricated using copper mold casting.The introduction of Cu resulted in the formation of large quantities of a-Fe nanoparticles embedded in the glas...A 2.5-mm Fe72.5B15.6Si7.8Nb1.7Zr1.7Cu0.7 glassy rod was successfully fabricated using copper mold casting.The introduction of Cu resulted in the formation of large quantities of a-Fe nanoparticles embedded in the glassy matrix after isothermal annealing.The Fe72.5B15.6Si7.8Nb1.7Zr1.7Cu0.7 nanocrystalline alloy exhibited high saturation magnetization(~1.26 T) and a low coercive force(~0.8 A/m) after annealing at 833 K for 15 min due to the precipitation of ~15-nm-sized a-Fe nanoparticles in the glassy matrix.The structural evolution of the FeBSiNbZrCu amorphous alloy during the annealing process was discussed using a dual-cluster model.展开更多
The steered covariance matrix(STCM) and its inverse matrix should be calculated in each beam for steered minimum variance(STMV) . The inverse matrix needs complex computation and restricts its application in engineeri...The steered covariance matrix(STCM) and its inverse matrix should be calculated in each beam for steered minimum variance(STMV) . The inverse matrix needs complex computation and restricts its application in engineering. Combining the integration character of one-phase regressive filter with the iterative formula of inverse matrix,an STMV iterative algorithm is proposed. The computational cost of the iterative algorithm is reduced approximately to be 2/M times of the original one when there are M sensors,and is more advantaged for the realization of the algorithm in real time. Simulation results show that the STMV iterative algorithm can preserve the characters of STMV on high azimuth resolution and weak target detection while the computational cost reduced sharply. The analysis on sea trial data proves that the proposed algorithm can estimate each target's azimuth even when the source powers differ in large scales or their bearings are very approximate.展开更多
This paper focuses on the spatial registration algorithm under the earth-center earth-fixed(ECEF)coordinate system for multiple mobile platforms.The sensor measurement biases are discussed with the attitude informatio...This paper focuses on the spatial registration algorithm under the earth-center earth-fixed(ECEF)coordinate system for multiple mobile platforms.The sensor measurement biases are discussed with the attitude information of the platform into consideration.First,the biased measurement model is constructed.Besides,the maximum likelihood registration(MLR)algorithm is discussed to simultaneously estimate the measurement biases and the target state.Finally,an improved online MLR(IMLR)algorithm is proposed through a sliding window of adaptive size.Simulation results demonstrate that the proposed IMLR algorithm effectively improves the realtime ability of the system and can approach similar estimation accuracy to the conventional MLR algorithm.展开更多
A new dynamic model of a variable-length rope,which could be used for the transient analysis of a buoy-rope-generator(BRG)wave energy system,was proposed in this paper.The model started from the basic dynamic equation...A new dynamic model of a variable-length rope,which could be used for the transient analysis of a buoy-rope-generator(BRG)wave energy system,was proposed in this paper.The model started from the basic dynamic equations of variable mass system,and took into account the physical properties such as axial force,shear and bending.According to the principle of D'Alembert-Lagrange,the equivalent integral weak formulation was firstly obtained,and through consistent linearization and isoparametric discretization,the finite element model of the variable-length rope was then derived.The Bathe scheme was employed to solve the model numerically,based on its excellent performance in solving nonlinear dynamic problems,and an automatic time step size algorithm was designed according to the number of iterations of the two substeps of Bathe scheme.The procedures of rope mesh regeneration were also put forward,where only one variable-length element was always located at the top end of the rope,and the rest were all fixed-length elements.The proposed variable-length rope model and solution schemes were verified through comparison with the results of a tank experiment.Finally,the transient dynamics of a kind of BRG system was analyzed and discussed.展开更多
In recent years,the construction of offshore wind farms is developing rapidly.As the wake effect of the upstream wind turbines seriously affect the performance of the downstream wind turbines,the wake effect of offsho...In recent years,the construction of offshore wind farms is developing rapidly.As the wake effect of the upstream wind turbines seriously affect the performance of the downstream wind turbines,the wake effect of offshore wind turbines has become one of the research hotspots.First,this article reviews the research methods of wake effects,including CFD numerical simulation method,wind turbine wake model based on roughness and engineering wake models.However,there is no general model that can be used directly.Then it puts forward some factors that affect the wake of offshore wind turbines.The turbulence intensity in offshore wind fields is lower than that in onshore wind fields.This makes the wake recovery length of offshore wind turbines longer than that of onshore wind turbines.Floating offshore wind turbines are simultaneously disturbed by wind loads and wave loads.Unsteady movement of the platform caused by wave loads.It affects the development and changes of the wake of wind turbines.In this regard,the focus of research on the wake effects of offshore wind farms will be the proposal of accurate prediction models for the wake effects of sea wind farms.展开更多
This study investigates the fabrication of hydroxyapatite(HAP)nano-coating on a gold-quartz crystal sensor used for quartz crystal microbalance with dissipation(QCM-D)measur ement using an electr ophoretic deposition ...This study investigates the fabrication of hydroxyapatite(HAP)nano-coating on a gold-quartz crystal sensor used for quartz crystal microbalance with dissipation(QCM-D)measur ement using an electr ophoretic deposition technique.Surface morphology and thickness of the HAP coating are examined via scanning electron microscopy and nano-indention testing.Its repeatability is verified via QCM-D testing.Results show that electrophor etic deposition with ultr asonic treatment is feasible and cost-effective for fabricating nano-thick HAP coatings on a QCM-D gold-quartz crystal sensor surface.Both suspension concentration and electric-field str ength influence the compactness of HAP coatings.There exists a non-linear re lationship between HAP coating compactness and the suspension concentration/electric-field strength.When the HAP suspension concentration is 30 g/and the applied electric-field strength is 150 V/cm,the HAP coating on the QCM-D gold-quartz crystal sensor surface is uniform and compact with a thickness of 35 nm and is tightly bonded to the sensor surface.The obtained HAP-coated sensor is thus suitable for QCM-D measurement.展开更多
Latent and sensible heat fluxes based on observations from a Black Pearl wave glider were estimated along the main stream of the Kuroshio Current from the East China Sea to the east coast of Japan,from December 2018 t...Latent and sensible heat fluxes based on observations from a Black Pearl wave glider were estimated along the main stream of the Kuroshio Current from the East China Sea to the east coast of Japan,from December 2018 to January 2019.It is found that the data obtained by the wave glider were comparable to the sea surface temperature data from the Operational Sea Surface Temperature and Sea Ice Analysis and the wind field data from WindSat.The Coupled Ocean Atmosphere Response Experiment 3.0(COARE 3.0)algorithm was used to calculate the change in air-sea turbulent heat flux along the Kuroshio.The averaged latent heat flux(LHF)and sensible heat flux(SHF)were 235 W/m^(2)and 134 W/m^(2),respectively,and the values in the Kuroshio were significant larger than those in the East China Sea.The LHF and SHF obtained from Objectively Analyzed Air-Sea Fluxes for the Global Oceans(OAFlux)were closer to those measured by the wave glider than those obtained from National Centers for Environmental Prediction(NCEP)reanalysis products.The maximum deviation occurred in the East China Sea and the recirculation zone of the Kuroshio(deviation of SHF>200 W/m^(2);deviation of LHF>400 W/m^(2)).This indicates that the NCEP and OAFlux products have large biases in areas with complex circulation.The wave glider has great potential to observe air-sea heat fluxes with a complex circulation structure.展开更多
Ultrasound has been used for antifouling on the surface of medical devices or food utensils,but it is rarely applied in marine anti-biofouling on underwater instruments.To understand whether ultrasonic antifouling is ...Ultrasound has been used for antifouling on the surface of medical devices or food utensils,but it is rarely applied in marine anti-biofouling on underwater instruments.To understand whether ultrasonic antifouling is suitable for underwater optical windows,the effect of ultrasonic conditions including frequency,power and duration on the removal of microbiofouling on the surface of polymethyl methacrylate(PMMA),a type of common optical material,was investigated in this study by three-factor and three-level orthogonal experiments.Before and after the ultrasonic treatment,both surface morphology and fouling degree of PMMA samples immersed in Escherichia coli suspension and seawater were characterized and quantified using laser scanning microscope.The results showed that ultrasonic treatment can effectively remove microfouling from the PMMA surface under suitable conditions.Ultrasonic technology has a great potential for the control of microfouling on the marine optical instruments.When compared with power and duration,ultrasonic frequency has a more significant effect on antifouling efficacy of ultrasound.It is useful for PMMA samples exposed to seawater within 2 days to conduct an antifouling treatment under the condition of an ultrasonic frequency of 20 kHz,ultrasonic power of 40 W,and ultrasonic duration of 7 min.展开更多
Dental erosion results in excessive tooth wear.The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood.In this study,the effects of fluoride(2...Dental erosion results in excessive tooth wear.The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood.In this study,the effects of fluoride(225 ppm F−)on the surface morphology and nano-mechanical and anti-wear properties of human tooth enamel were investigated to explore whether low-concentration NaF solution could help protect tooth enamel from erosion.In total,40 enamel samples were divided into 5 groups,viz.group O:original surface with no treatment,group F:fluoride treatment(NaF,225 ppm F−,pH 6.3),group E:erosion treatment(0.001 M citric acid,pH 3.2,3 min),group EF:erosion treatment and then fluorination and group FE:fluoride treatment and then erosion.The mechanical and anti-wear properties of enamel samples were examined using a nano-indentation/scratch technique.Both surface morphology and scratch morphology of enamel samples were observed with scanning electron microscopy.The results showed that,from the perspectives of surface morphology and anti-wear properties,fluorination with low-concentration fluoride(225 ppm F−)before erosion has a certain potential for protection against dental erosion.Fluoride treatment after erosion has no obvious impact on the remineralisation of eroded enamel.展开更多
Layered sodium manganese oxides(LSMOs),with two-dimensional channels for ion diffusion,have been regarded as the promising electrode materials in the application of asymmetric supercapacitors(ASCs).In this work,the la...Layered sodium manganese oxides(LSMOs),with two-dimensional channels for ion diffusion,have been regarded as the promising electrode materials in the application of asymmetric supercapacitors(ASCs).In this work,the layered Na0.5Mn2O4·1.5H2O was synthesized through a facile hydrothermal method by controlling the molar ratio of sodium and manganese.When the molar ratio of sodium to manganese is 3:1,Na0.5Mn2O4·1.5H2O has shown the best capacitance of 369 F/g with current density of 0.5 A/g,and maintained a capacitance of 265 F/g after 2000 cycles.The asymmetric supercapacitor consists of the sodium manages oxides as the positive electrode and active carbon(AC)as the negative electrode in 1 mol/L Na2SO4 solution.The voltage of the asymmetric supercapacitor has been expanded to 0~2 V with an energy density of 10.13 Wh/kg at a power density of 500 W/kg based on the total weight of both active electrode materials when the mass ratio of AC to Na0.5Mn2O4·1.5H2O was 3:1.展开更多
基金Supported by the National Natural Science Foundation of China(42275039 and 42022038)。
文摘Atmospheric radiation is a major branch of atmospheric physics that encompasses the fundamental theories of atmospheric absorption,particle scattering(aerosols and clouds),and radiative transfer.Specifically,the simulations of atmospheric gaseous absorption and scattering properties of particles are the essential components of atmospheric radiative transfer models.Atmospheric radiation has important applications in weather,climate,data assimilation,remote sensing,and atmospheric detection studies.In PartⅠ,a comprehensive review of the progress in the field of gas absorption and particle scattering research over the past 30 years with a particular emphasis on the contributions from Chinese scientists is presented.The review of gas absorption includes the construction of absorption databases,the impact of different atmospheric absorption algorithms on radiative calculations,and their applications in weather and climate models and remote sensing.The review on particle scattering starts with the theoretical and computational methods and subsequently explores the optical modeling of aerosols and clouds in remote sensing and atmospheric models.Additionally,the paper discusses potential future research directions in this field.
基金H.L.acknowledges the National Key Research and Development Program of China(2017YFB0405400)from the Ministry of Science and Technology(MOST)of Chinathe Natural Science Foundation for Distinguished Young Scientist of Shandong Province(Grant No.JQ201814)+6 种基金We thank the Project of“20 items of University”of Jinan(2018GXRC031)W.Z thanks Taishan Scholars Project Special Funds(tsqn201812083)and NSFC(No.52022037)The authors show their gratitude to the National Natural Science Foundation of China(NSFC grant No.51802113,51802116)the Natural Science Foundation of Shandong Province,China(grant No.ZR2019BEM040,ZR2018BEM015)M.H.R.thanks the National Science Foundation China(NSFC,Project 52071225)the National Science Center and the Czech Republic under the ERDF program“Institute of Environmental Technology-Excellent Research”(No.CZ.02.1.01/0.0/0.0/16_019/0000853)the Sino-German Research Institute for support(Project No.GZ 1400).
文摘The rapid development of two-dimensional(2D)transition-metal dichalcogenides has been possible owing to their special structures and remarkable properties.In particular,palladium diselenide(PdSe_(2))with a novel pentagonal structure and unique physical characteristics have recently attracted extensive research inter-est.Consequently,tremendous research progress has been achieved regarding the physics,chemistry,and electronics of PdSe_(2).Accordingly,in this review,we recapitulate and summarize the most recent research on PdSe_(2),including its structure,properties,synthesis,and appli-cations.First,a mechanical exfoliation method to obtain PdSe_(2) nanosheets is introduced,and large-area synthesis strate-gies are explained with respect to chemical vapor deposition and metal selenization.Next,the electronic and optoelectronic properties of PdSe_(2) and related hetero-structures,such as field-effect transistors,photodetectors,sensors,and thermoelec-tric devices,are discussed.Subsequently,the integration of systems into infrared image sensors on the basis of PdSe_(2) van der Waals heterostructures is explored.Finally,future opportunities are highlighted to serve as a general guide for physicists,chemists,materials scientists,and engineers.Therefore,this com-prehensive review may shed light on the research conducted by the 2D material community.
基金Supported by the Youth Science and Technology Innovation Program of Xiamen Ocean and Fisheries Development Special Funds(No.23ZHZB034QCB38).
文摘This article provides an overview of the application of bionic technology in marine cruising equipment,discussing its research progress and future development trends.Marine cruising is a crucial means of gaining insights into the marine environment and conducting scientific research.However,conventional marine cruising equipment faces numerous challenges when dealing with complex and ever-changing marine environments.Bionic technology,as a means of drawing inspiration from the structure and functions of living organisms,offers new approaches and methods to address the challenges faced by marine cruising equipment and has found widespread application.The article primarily focuses on the applications and historical developments of bionic technology in propulsion methods,drag reduction,and surface antifouling.It summarizes the design principles,manufacturing techniques,and optimization methods for marine biomimetic cruising equipment.Finally,this paper analyzes the achievements,challenges,and future directions of bionic technology in marine cruising equipment.The application of bionic technology in marine cruising equipment holds vast potential for development,enabling us to better confront the challenges of marine exploration and research by drawing wisdom from nature and driving advancements in marine science.
基金financially supported by the National Natural Science Foundation of China (Grant Nos.51909109 and 52101314)the Natural Science Foundation of Jiangsu Province (Grant No.BK20190967)。
文摘Wind farms generally consist of a single turbine installed with the same hub height. As the scale of turbines increases,wake interference between turbines becomes increasingly significant, especially for floating wind turbines(FWT).Some researchers find that wind farms with multiple hub heights could increase the annual energy production(AEP),while previous studies also indicate that wake meandering could increase fatigue loading. This study investigates the wake interaction within a hybrid floating wind farm with multiple hub heights. In this study, FAST.Farm is employed to simulate a hybrid wind farm which consists of four semi-submersible FWTs(5MW and 15MW) with two different hub heights. Three typical wind speeds(below-rated, rated, and over-rated) are considered in this paper to investigate the wake meandering effects on the dynamics of two FWTs. Damage equivalent loads(DEL) of the turbine critical components are computed and analyzed for several arrangements determined by the different spacing of the four turbines. The result shows that the dynamic wake meandering significantly affects downstream turbines’ global loadings and load effects. Differences in DEL show that blade-root flapwise bending moments and mooring fairlead tensions are sensitive to the spacing of the turbines.
基金financially supported by the National Natural Science Foundation of China(Grant No.51779109)the Natural Science Foundation of Jiangsu Province(Grant No.BK20171306)
文摘A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The main dimension, the special variable cross-section column and the cabin arrangement of the octagonal pontoon are introduced based on the result. The numerical simulation is adapted to study the effects of current incidence angles and reduced velocities on this platform’s sway motion response. The 300 m water depth equivalent truncated mooring system is adopted for the model tests. The model tests are carried out to check the reliability of numerical simulation. The results consist of surge, sway and yaw motions, as well as motion trajectories. The maximum sway amplitudes for different types of offshore platform is also studied. The main results show that the peak frequencies of sway motion under different current incidence angles and reduced velocities vary around the natural frequency. The analysis result of flow field indicates that the change of distribution of vortex in vertical presents significant influences on the VIM of platform. The trend of sway amplitude ratio curve of this new type FDPSO differs from the other types of platform. Under 45° current incidence angle, the sway amplitude of this new type of FDPSO is much smaller than those of other types of offshore platform at 4.4 ≤ V;≤ 8.9. The typical ‘8’ shape trajectory does not appear in the platform’s motion trajectories.
基金the National Natural Science Foundation of China(Grant Nos.51672114 and 51603091)the Natural Science Foundation of Jiangsu Province(BK20181469)+1 种基金the Joint Open Fund of Jiangsu Collaborative Innovation Center for Ecological Building Material and Environmental Protection Equipment and Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province,the Open Project of Key Laboratory for Ecological-Environment Materials of Jiangsu Province(JH201815)the Foundation from Marine Equipment and Technology Institute for Jiangsu University of Science and Technology,China(HZ20190004).
文摘As the anode material of lithium-ion battery,silicon-based materials have a high theoretical capacity,but their volume changes greatly in the charging and discharging process.To ameliorate the volume expansion issue of silicobased anode materials,g-C_(3)N_(4)/Si nanocomposites are prepared by using the magnesium thermal reduction technique.It is well known that g-C_(3)N_(4)/Si nanocomposites can not only improve the electronic transmission ability,but also ameliorate the physical properties of the material for adapting the stress and strain caused by the volume expansion of silicon in the lithiation and delithiation process.When g-C_(3)N_(4)/Si electrode is evaluated,the initial discharge capacity of g-C_(3)N_(4)/Si nanocomposites is as high as 1033.3 mAh/g at 0.1 A/g,and its reversible capacity is maintained at 548 mAh/g after 400 cycles.Meanwhile,the improved rate capability is achieved with a relatively high reversible specific capacity of 218 mAh/g at 2.0 A/g.The superior lithium storage performances benefit from the unique g-C_(3)N_(4)/Si nanostructure,which improves electroconductivity,reduces volume expansion,and accelerates lithiumion transmission compared to pure silicon.
基金This work was financially supported by the National Natural Science Foundation of China(51672114,21908085,21806077)Natural Science Foundation of Jiangsu Province(BK20190961)+2 种基金Foundation from Marine Equipment and Technology Institute for Jiangsu University of Science and Technology(HZ20190004)Postdoctoral Research Foundation of Jiangsu Province(2020Z291)High-tech Ship Research Project of the Ministry of Industry and Information Technology(No.[2017]614).
文摘Herein,we develop cost-efficient superhigh-performance of engineering carbonaceous adsorbent from cigarette butts using combined wet-impregnated and re-dispersed method of KOH,which optimizes the implant approach of activator,breaking the restriction of selective capture of toluene using traditional activated carbon.The Brunauer-Emmett-Teller(BET)surface area and pore volume of targeted adsorbent can attain 3088 m^(2)·g^(-1) and 1.61 cm^(3)·g^(-1),respectively,by optimizing the temperaturedependent synthetic factor effect of the adsorbent.The adsorption capacity of resultant adsorbent for presenting volatile benzene and toluene shows a positive correlation with increasing carbonization temperature of carbon precursor.Besides,we demonstrated the unsmoked and smoked butts derived adsorbents afford feeble difference in saturated adsorbed capacity of volatile organic compounds(VOCs).The highest adsorption capacity of sample CF-800 for benzene and toluene in CF group is as high as 1268.1 and 1181.6 mg·g^(-1) respectively,slightly higher than that of sample UF-800,but far outperforming reported other adsorbents.The predicted adsorption selectivity of CF-800 and UF-800 for C_(7)H_(8)/H_(2)O(g)using the DIH(difference of isosteric heats)equation reach up to ca.3800 and 7500 respectively,indicating the weak adsorbability of water vapor on the developed adsorbent and greater superiority of the smoked butts derived adsorbents in selective capture of VOCs at low relative humidity in the competitive adsorption process for practical mixed VOCs.
基金the Key Science and Technology Plan of Power China Huadong Engineering Corporation(No.KY2018-ZD-01)China and the National Natural Science Foundations of China(No.51909248)。
文摘Outgoing waves arising from high-velocity impacts between soil and structure can be reflected by the conventional truncated boundaries.Absorbing boundary conditions(ABCs),to attenuate the energy of the outward waves,are necessary to ensure the proper representation of the kinematic field and the accurate quantification of impact forces.In this paper,damping layer and dashpot ABCs are implemented in the material point method(MPM)with slight adjustments.Benchmark scenarios of different dynamic problems are modelled with the ABCs configured.Feasibility of the ABCs is assessed through the velocity fluctuations at specific observation points and the impact force fluctuations on the structures.The impact forces predicted by the MPM with ABCs are verified by comparison with those estimated using a computational fluid dynamics approach.
基金was supported by the Natural Science Foundation of Shandong Province,China(ZR201801300002,ZR2016DM17,ZR2018ZB0523ZR2019PD004)+2 种基金the Natural Science Foundation of China(31700447 and 41201305)Science and Technology Fundamental Resources Investigation Program of China(2018FY100300)National Key Research and Development Program of China(2016YFD0201301 and 2016YFD0201200).
文摘Herb residue vermicompost is thought to have high agriculture value,while its effects on soil microbial activities have not been fully understood.Here,soil microbial biomass,respiration and enzyme activities in soil planted with maize were compared among treatments amended with herb residue vermicompost at rates of 25,50,75 and 100 g kg^(-1),chemical NPK fertilizer and no fertilizer(the control).Our results showed that soil microbial biomass carbon,respiration,and alkaline phosphatase,urease,and invertase activities were greater in soil amended with herb residue vermicompost than the unfertilized control(P<0.05).Compared with chemical fertilizer,herb residue vermicompost increased soil urease and alkaline phosphatase activities at each application rate,promoted soil respiration and microbial biomass carbon at the application rates of 50,75 and 100 g kg^(-1),and increased soil inverse activity at the application rates of 75 and 100 g kg^(-1).In conclusion,herb residue vermicompost supported greater soil microbial biomass,respiration and enzyme activities than conventional NPK fertilizer,and the effect was larger when higher rates of herb residue vermicompost were added.
基金Supported by the National Natural Science Foundation of China(No.51502117,No.21671084)Key Research&Development Plan of Zhenjiang City(No.SH2017051)+1 种基金Foundation from Marine Equipment and Technology Institute for Jiangsu University of Science and Technology(No.HZ20170015)Six Talent Peaks Project in Jiangsu Province(No.2014-XCL-008)
文摘PbO2/Co3O4 composites were prepared on a Ti substrate by means of a composite electrodeposition method in Pb2+ plating solution containing dissolved nano-Co3O4 particles. X-ray diffraction（XRD）, scanning electron microscopy（SEM）, energy dispersive spectrometry（EDS） and transmission electron microscopy（TEM） were used to characterize the chemical composition and morphology of the PbO2/Co3O4 composites. The electrochemical and capacitance performance of the composites were investigated by cyclic voltammetry（CV）, charge-discharge tests and electrochemical impedance（EIS）. The results indicate that the composites comprise rutile phase Co3O4 and β-PbO2. In addition, the surface of the composite electrode is rough and porous. The PbO2/Co3O4 composites exhibit a high specific capacitance up to 215 F/g, which is ten times higher than that of the pure-PbO2 and two times higher than that of the pure-Co3O4 in 1 mol/L NaOH electrolytes.
基金financially supported by the National Key R&D Program of China(No.2016YFB1100103)the National Natural Science Foundation of China(No.51801079)+1 种基金the Natural Science Foundation for Young Scientists of Jiangsu,China(Nos.BK20180985 and BK20180987)the Natural Science Foundation in Higher Education of Jiangsu,China(No.18KJB430011).
文摘A 2.5-mm Fe72.5B15.6Si7.8Nb1.7Zr1.7Cu0.7 glassy rod was successfully fabricated using copper mold casting.The introduction of Cu resulted in the formation of large quantities of a-Fe nanoparticles embedded in the glassy matrix after isothermal annealing.The Fe72.5B15.6Si7.8Nb1.7Zr1.7Cu0.7 nanocrystalline alloy exhibited high saturation magnetization(~1.26 T) and a low coercive force(~0.8 A/m) after annealing at 833 K for 15 min due to the precipitation of ~15-nm-sized a-Fe nanoparticles in the glassy matrix.The structural evolution of the FeBSiNbZrCu amorphous alloy during the annealing process was discussed using a dual-cluster model.
文摘The steered covariance matrix(STCM) and its inverse matrix should be calculated in each beam for steered minimum variance(STMV) . The inverse matrix needs complex computation and restricts its application in engineering. Combining the integration character of one-phase regressive filter with the iterative formula of inverse matrix,an STMV iterative algorithm is proposed. The computational cost of the iterative algorithm is reduced approximately to be 2/M times of the original one when there are M sensors,and is more advantaged for the realization of the algorithm in real time. Simulation results show that the STMV iterative algorithm can preserve the characters of STMV on high azimuth resolution and weak target detection while the computational cost reduced sharply. The analysis on sea trial data proves that the proposed algorithm can estimate each target's azimuth even when the source powers differ in large scales or their bearings are very approximate.
基金the National Natural Science Foundation of China(No.61627810)the National Key Research and Development Program of China(No.2018YFB1305003)the Joint Fund of Advanced Aerospace Manufacturing Technology Research(No.2017-JCJQ-ZQ-031)。
文摘This paper focuses on the spatial registration algorithm under the earth-center earth-fixed(ECEF)coordinate system for multiple mobile platforms.The sensor measurement biases are discussed with the attitude information of the platform into consideration.First,the biased measurement model is constructed.Besides,the maximum likelihood registration(MLR)algorithm is discussed to simultaneously estimate the measurement biases and the target state.Finally,an improved online MLR(IMLR)algorithm is proposed through a sliding window of adaptive size.Simulation results demonstrate that the proposed IMLR algorithm effectively improves the realtime ability of the system and can approach similar estimation accuracy to the conventional MLR algorithm.
基金This work was funded by the National Natural Science Foundation of China(Grant No.51709102)the Natural Science Foundation of Hunan Province(Grant No.2019JJ50166)the Scientific Research Fund of Hunan Provincial Education Department(Grant No.19B184).
文摘A new dynamic model of a variable-length rope,which could be used for the transient analysis of a buoy-rope-generator(BRG)wave energy system,was proposed in this paper.The model started from the basic dynamic equations of variable mass system,and took into account the physical properties such as axial force,shear and bending.According to the principle of D'Alembert-Lagrange,the equivalent integral weak formulation was firstly obtained,and through consistent linearization and isoparametric discretization,the finite element model of the variable-length rope was then derived.The Bathe scheme was employed to solve the model numerically,based on its excellent performance in solving nonlinear dynamic problems,and an automatic time step size algorithm was designed according to the number of iterations of the two substeps of Bathe scheme.The procedures of rope mesh regeneration were also put forward,where only one variable-length element was always located at the top end of the rope,and the rest were all fixed-length elements.The proposed variable-length rope model and solution schemes were verified through comparison with the results of a tank experiment.Finally,the transient dynamics of a kind of BRG system was analyzed and discussed.
基金The work was sponsored by the Open Fund of Key Laboratory of Wind Energy and Solar Energy Technology(Inner Mongolia University of Technology),Ministry of Education(No.2020ZD01)in Chinathe Fund of Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)(ZJW-2019-02).
文摘In recent years,the construction of offshore wind farms is developing rapidly.As the wake effect of the upstream wind turbines seriously affect the performance of the downstream wind turbines,the wake effect of offshore wind turbines has become one of the research hotspots.First,this article reviews the research methods of wake effects,including CFD numerical simulation method,wind turbine wake model based on roughness and engineering wake models.However,there is no general model that can be used directly.Then it puts forward some factors that affect the wake of offshore wind turbines.The turbulence intensity in offshore wind fields is lower than that in onshore wind fields.This makes the wake recovery length of offshore wind turbines longer than that of onshore wind turbines.Floating offshore wind turbines are simultaneously disturbed by wind loads and wave loads.Unsteady movement of the platform caused by wave loads.It affects the development and changes of the wake of wind turbines.In this regard,the focus of research on the wake effects of offshore wind farms will be the proposal of accurate prediction models for the wake effects of sea wind farms.
基金the National Natural Science Foundation of China(51535010)the China Postdoctoral Science Foundation(2017M622241)+1 种基金the Special Funds for Shandong Province Postdoctoral Innovative Projects(201703094)the Fundamental Research Funds for the Central Universities(2682018QY01).
文摘This study investigates the fabrication of hydroxyapatite(HAP)nano-coating on a gold-quartz crystal sensor used for quartz crystal microbalance with dissipation(QCM-D)measur ement using an electr ophoretic deposition technique.Surface morphology and thickness of the HAP coating are examined via scanning electron microscopy and nano-indention testing.Its repeatability is verified via QCM-D testing.Results show that electrophor etic deposition with ultr asonic treatment is feasible and cost-effective for fabricating nano-thick HAP coatings on a QCM-D gold-quartz crystal sensor surface.Both suspension concentration and electric-field str ength influence the compactness of HAP coatings.There exists a non-linear re lationship between HAP coating compactness and the suspension concentration/electric-field strength.When the HAP suspension concentration is 30 g/and the applied electric-field strength is 150 V/cm,the HAP coating on the QCM-D gold-quartz crystal sensor surface is uniform and compact with a thickness of 35 nm and is tightly bonded to the sensor surface.The obtained HAP-coated sensor is thus suitable for QCM-D measurement.
基金The National Key R&D Program of China under contract Nos 2017YFC0305904,2017YFC0305902 and 2017YFC0305804the National Natural Science Foundation of China under contract No.44006020+3 种基金the Guangdong Science and Technology Project under contract No.2019A1515111044the Shandong Provincial Key Research and Development Program(Major Scientific and Technological Innovation Project)under contract No.2019JZZY020701the Wenhai Program of Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2017WHZZB0101the CAS Key Technology Talent Program under contract No.202012292205。
文摘Latent and sensible heat fluxes based on observations from a Black Pearl wave glider were estimated along the main stream of the Kuroshio Current from the East China Sea to the east coast of Japan,from December 2018 to January 2019.It is found that the data obtained by the wave glider were comparable to the sea surface temperature data from the Operational Sea Surface Temperature and Sea Ice Analysis and the wind field data from WindSat.The Coupled Ocean Atmosphere Response Experiment 3.0(COARE 3.0)algorithm was used to calculate the change in air-sea turbulent heat flux along the Kuroshio.The averaged latent heat flux(LHF)and sensible heat flux(SHF)were 235 W/m^(2)and 134 W/m^(2),respectively,and the values in the Kuroshio were significant larger than those in the East China Sea.The LHF and SHF obtained from Objectively Analyzed Air-Sea Fluxes for the Global Oceans(OAFlux)were closer to those measured by the wave glider than those obtained from National Centers for Environmental Prediction(NCEP)reanalysis products.The maximum deviation occurred in the East China Sea and the recirculation zone of the Kuroshio(deviation of SHF>200 W/m^(2);deviation of LHF>400 W/m^(2)).This indicates that the NCEP and OAFlux products have large biases in areas with complex circulation.The wave glider has great potential to observe air-sea heat fluxes with a complex circulation structure.
基金This work was supported by the National Natural Science Foundation of China(51535010)the Special Funds for Shandong Province Postdoctoral Innovative Projects(201703094)the Fundamental Research Funds for the Central Universities(2682018QY01).
文摘Ultrasound has been used for antifouling on the surface of medical devices or food utensils,but it is rarely applied in marine anti-biofouling on underwater instruments.To understand whether ultrasonic antifouling is suitable for underwater optical windows,the effect of ultrasonic conditions including frequency,power and duration on the removal of microbiofouling on the surface of polymethyl methacrylate(PMMA),a type of common optical material,was investigated in this study by three-factor and three-level orthogonal experiments.Before and after the ultrasonic treatment,both surface morphology and fouling degree of PMMA samples immersed in Escherichia coli suspension and seawater were characterized and quantified using laser scanning microscope.The results showed that ultrasonic treatment can effectively remove microfouling from the PMMA surface under suitable conditions.Ultrasonic technology has a great potential for the control of microfouling on the marine optical instruments.When compared with power and duration,ultrasonic frequency has a more significant effect on antifouling efficacy of ultrasound.It is useful for PMMA samples exposed to seawater within 2 days to conduct an antifouling treatment under the condition of an ultrasonic frequency of 20 kHz,ultrasonic power of 40 W,and ultrasonic duration of 7 min.
基金supported by the National Natural Science Foundation of China(No.51535010).
文摘Dental erosion results in excessive tooth wear.The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood.In this study,the effects of fluoride(225 ppm F−)on the surface morphology and nano-mechanical and anti-wear properties of human tooth enamel were investigated to explore whether low-concentration NaF solution could help protect tooth enamel from erosion.In total,40 enamel samples were divided into 5 groups,viz.group O:original surface with no treatment,group F:fluoride treatment(NaF,225 ppm F−,pH 6.3),group E:erosion treatment(0.001 M citric acid,pH 3.2,3 min),group EF:erosion treatment and then fluorination and group FE:fluoride treatment and then erosion.The mechanical and anti-wear properties of enamel samples were examined using a nano-indentation/scratch technique.Both surface morphology and scratch morphology of enamel samples were observed with scanning electron microscopy.The results showed that,from the perspectives of surface morphology and anti-wear properties,fluorination with low-concentration fluoride(225 ppm F−)before erosion has a certain potential for protection against dental erosion.Fluoride treatment after erosion has no obvious impact on the remineralisation of eroded enamel.
文摘Layered sodium manganese oxides(LSMOs),with two-dimensional channels for ion diffusion,have been regarded as the promising electrode materials in the application of asymmetric supercapacitors(ASCs).In this work,the layered Na0.5Mn2O4·1.5H2O was synthesized through a facile hydrothermal method by controlling the molar ratio of sodium and manganese.When the molar ratio of sodium to manganese is 3:1,Na0.5Mn2O4·1.5H2O has shown the best capacitance of 369 F/g with current density of 0.5 A/g,and maintained a capacitance of 265 F/g after 2000 cycles.The asymmetric supercapacitor consists of the sodium manages oxides as the positive electrode and active carbon(AC)as the negative electrode in 1 mol/L Na2SO4 solution.The voltage of the asymmetric supercapacitor has been expanded to 0~2 V with an energy density of 10.13 Wh/kg at a power density of 500 W/kg based on the total weight of both active electrode materials when the mass ratio of AC to Na0.5Mn2O4·1.5H2O was 3:1.
